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Sample records for models perform poorly

  1. Temporal diagnostic analysis of the SWAT model to detect dominant periods of poor model performance

    Science.gov (United States)

    Guse, Björn; Reusser, Dominik E.; Fohrer, Nicola

    2013-04-01

    four reoccurring patterns of typical model performance, which can be related to different phases of the hydrograph. Overall, the baseflow cluster has the lowest performance. By combining the periods with poor model performance with the dominant model components during these phases, the groundwater module was detected as the model part with the highest potential for model improvements. The detection of dominant processes in periods of poor model performance enhances the understanding of the SWAT model. Based on this, concepts how to improve the SWAT model structure for the application in German lowland catchment are derived.

  2. 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.

  3. Stereotactic Radiosurgery for Poor Performance Status Patients

    Energy Technology Data Exchange (ETDEWEB)

    Kubicek, Gregory J., E-mail: kubicek-gregory@cooperhealth.edu [Department of Radiation Oncology, Cooper University Hospital, Camden, New Jersey (United States); Turtz, Alan [Department of Neurological Surgery, Cooper University Hospital, Camden, New Jersey (United States); Xue, Jinyu; Patel, Ashish; Richards, Gregory; LaCouture, Tamara [Department of Radiation Oncology, Cooper University Hospital, Camden, New Jersey (United States); Cappelli, Louis; Diestelkamp, Tim [Rowan Graduate School, Camden, New Jersey (United States); Saraiya, Piya [Department of Diagnostic Radiology, Cooper University Hospital, Camden, New Jersey (United States); Bexon, Anne [Department of Neurological Surgery, Cooper University Hospital, Camden, New Jersey (United States); Lerman, Nati [Department of Medical Oncology, Cooper University Hospital, Camden, New Jersey (United States); Goldman, Howard Warren [Department of Neurological Surgery, Cooper University Hospital, Camden, New Jersey (United States)

    2016-07-01

    Purpose: Patients with poor performance status (PS), usually defined as a Karnofsky Performance Status of 60 or less, were not eligible for randomized stereotactic radiosurgery (SRS) studies, and many guidelines suggest that whole-brain radiation therapy (WBRT) is the most appropriate treatment for poor PS patients. Methods and Materials: In this retrospective review of our SRS database, we identified 36 patients with PS of 60 or less treated with SRS for central nervous system (CNS) metastatic disease. PS, as defined by the Karnofsky Performance Status, was 60 (27 patients), 50 (8 patients), or 40 (1 patient). The median number of CNS lesions treated was 3. Results: Median overall survival (OS) was 7.2 months (range, 0.73-25.6 months). Fifteen patients (41%) were alive at 6 months, and 6 patients (16.6%) were alive at 1 year. There was no difference in OS in patients who underwent previous WBRT. There were no local failures or cases of radiation toxicity. Distant CNS failures were seen in 9 patients (25%). Conclusions: Our patients with poor PS had reasonable median OS and relatively low distant CNS failure rates. Patients in this patient population may be ideal candidates for SRS compared with WBRT given the low incidence of distant failure over their remaining lives and the favorable logistics of single-fraction treatment for these patients with debility and their caregivers.

  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. 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...

  7. Common Characteristics of Good and Poorly Performing AC Pavements

    Science.gov (United States)

    1999-12-01

    This report documents the analysis and findings of a study to identify the site conditions and design/construction features of : flexible pavements that lead to good performance and those that lead to poor performance. Data from the Long Term Pavemen...

  8. 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...

  9. 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

  10. Three-dimensional models of metal-poor stars

    International Nuclear Information System (INIS)

    Collet, R

    2008-01-01

    I present here the main results of recent realistic, three-dimensional (3D), hydrodynamical simulations of convection at the surface of metal-poor red giant stars. I discuss the application of these convection simulations as time-dependent, 3D, hydrodynamical model atmospheres to spectral line formation calculations and abundance analyses. The impact of 3D models on derived elemental abundances is investigated by means of a differential comparison of the line strengths predicted in 3D under the assumption of local thermodynamic equilibrium (LTE) with the results of analogous line formation calculations performed with classical, 1D, hydrostatic model atmospheres. The low surface temperatures encountered in the upper photospheric layers of 3D model atmospheres of very metal-poor stars cause spectral lines of neutral metals and molecules to appear stronger in 3D than in 1D calculations. Hence, 3D elemental abundances derived from such lines are significantly lower than estimated by analyses with 1D models. In particular, differential 3D-1D LTE abundances for C, N and O derived from CH, NH and OH lines are found to be in the range -0.5 to - 1 dex. Large negative differential 3D-1D corrections to the Fe abundance are also computed for weak low-excitation Fe i lines. The application of metal-poor 3D models to the spectroscopic analysis of extremely iron-poor halo stars is discussed.

  11. 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.

  12. Understanding Preclerkship Medical Students' Poor Performance in Prescription Writing.

    Science.gov (United States)

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

    2016-05-01

    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. 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 questionnaire with closed- and open-ended items. All 157 students participated in the study (response rate: 100.0%). The most frequently cited reasons for poor performance in OSPE stations were an inability to select the correct drugs (79.6%), treatment duration (69.4%), drug quantity (69.4%) and drug formulation (68.2%). Additionally, students reported inadequate time for completing the stations (68.8%). During focus group discussions, students reported other reasons for poor performance, including examination stress and the difficulty of the stations. Absenteeism was attributed to the length of each session (55.4%), lack of interest (50.3%), reliance on peers for information (48.4%) and optional attendance policies (47.1%). Repetitive material, large group sessions, unmet student expectations and the proximity of the sessions to summative examinations were also indicated to contribute to absenteeism according to open-ended responses or focus group discussions. This study suggests that AGU medical students perform poorly in prescription writing OSPE stations because of inadequate clinical pharmacology knowledge. Participation in prescription writing sessions needs to be enhanced by addressing the concerns identified in this study. Strategies to improve attendance and performance should take into account the learner-teacher relationship.

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

    Directory of Open Access Journals (Sweden)

    Henry James

    2016-05-01

    Full Text Available 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 questionnaire with closed- and open-ended items. Results: All 157 students participated in the study (response rate: 100.0%. The most frequently cited reasons for poor performance in OSPE stations were an inability to select the correct drugs (79.6%, treatment duration (69.4%, drug quantity (69.4% and drug formulation (68.2%. Additionally, students reported inadequate time for completing the stations (68.8%. During focus group discussions, students reported other reasons for poor performance, including examination stress and the difficulty of the stations. Absenteeism was attributed to the length of each session (55.4%, lack of interest (50.3%, reliance on peers for information (48.4% and optional attendance policies (47.1%. Repetitive material, large group sessions, unmet student expectations and the proximity of the sessions to summative examinations were also indicated to contribute to absenteeism according to open-ended responses or focus group discussions. Conclusion: This study suggests that AGU medical students perform poorly in prescription writing OSPE stations because of inadequate clinical pharmacology knowledge. Participation in prescription writing sessions needs to be enhanced by addressing the concerns identified in this study. Strategies to improve attendance and performance should take into account the learner-teacher relationship.

  14. 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.

  15. 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.

  16. Defining poor and optimum performance in an IVF programme.

    Science.gov (United States)

    Castilla, Jose A; Hernandez, Juana; Cabello, Yolanda; Lafuente, Alejandro; Pajuelo, Nuria; Marqueta, Javier; Coroleu, Buenaventura

    2008-01-01

    At present there is considerable interest in healthcare administration, among professionals and among the general public concerning the quality of programmes of assisted reproduction. There exist various methods for comparing and analysing the results of clinical activity, with graphical methods being the most commonly used for this purpose. As yet, there is no general consensus as to how the poor performance (PP) or optimum performance (OP) of assisted reproductive technologies should be defined. Data from the IVF/ICSI register of the Spanish Fertility Society were used to compare and analyse different definitions of PP or OP. The primary variable best reflecting the quality of an IVF/ICSI programme was taken to be the percentage of singleton births per IVF/ICSI cycle initiated. Of the 75 infertility clinics that took part in the SEF-2003 survey, data on births were provided by 58. A total of 25 462 cycles were analysed. The following graphical classification methods were used: ranking of the proportion of singleton births per cycles started in each centre (league table), Shewhart control charts, funnel plots, best and worst-case scenarios and state of the art methods. The clinics classified as producing PP or OP varied considerably depending on the classification method used. Only three were rated as providing 'PP' or 'OP' by all methods, unanimously. Another four clinics were classified as 'poor' or 'optimum' by all the methods except one. On interpreting the results derived from IVF/ICSI centres, it is essential to take into account the characteristics of the method used for this purpose.

  17. Identifying poor performance among doctors in NHS organizations.

    Science.gov (United States)

    Locke, Rachel; Scallan, Samantha; Leach, Camilla; Rickenbach, Mark

    2013-10-01

    To account for the means by which poor performance among career doctors is identified by National Health Service organizations, whether the tools are considered effective and how these processes may be strengthened in the light of revalidation and the requirement for doctors to demonstrate their fitness to practice. This study sought to look beyond the 'doctor as individual'; as well as considering the typical approaches to managing the practice of an individual, the systems within which the doctor is working were reviewed, as these are also relevant to standards of performance. A qualitative review was undertaken consisting of a literature review of current practice, a policy review of current documentation from 15 trusts in one deanery locality, and 14 semi-structured interviews with respondents with an overview of processes in use. The framework for the analysis of the data considered tools at three levels: individual, team and organizational. Tools are, in the main, reactive--with an individual focus. They rely on colleagues and others to speak out, so their effectiveness is hindered by a reluctance to do so. Tools can lack an evidence base for their use, and there is limited linking of data across contexts and tools. There is more work to be done in evaluating current tools and developing stronger processes. Linkage between data sources needs to be improved and proactive tools at the organizational level need further development to help with the early identification of performance issues. This would also assist in balancing a wider systems approach with a current over emphasis on individual doctors. © 2012 John Wiley & Sons Ltd.

  18. 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 ...

  19. 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.

  20. 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.

  1. Effect of exposure to good vs poor medical trainee performance on attending physician ratings of subsequent performances.

    Science.gov (United States)

    Yeates, Peter; O'Neill, Paul; Mann, Karen; Eva, Kevin W

    2012-12-05

    Competency-based models of education require assessments to be based on individuals' capacity to perform, yet the nature of human judgment may fundamentally limit the extent to which such assessment is accurately possible. To determine whether recent observations of the Mini Clinical Evaluation Exercise (Mini-CEX) performance of postgraduate year 1 physicians influence raters' scores of subsequent performances, consistent with either anchoring bias (scores biased similar to previous experience) or contrast bias (scores biased away from previous experience). Internet-based randomized, blinded experiment using videos of Mini-CEX assessments of postgraduate year 1 trainees interviewing new internal medicine patients. Participants were 41 attending physicians from England and Wales experienced with the Mini-CEX, with 20 watching and scoring 3 good trainee performances and 21 watching and scoring 3 poor performances. All then watched and scored the same 3 borderline video performances. The study was completed between July and November 2011. The primary outcome was scores assigned to the borderline videos, using a 6-point Likert scale (anchors included: 1, well below expectations; 3, borderline; 6, well above expectations). Associations were tested in a multivariable analysis that included participants' sex, years of practice, and the stringency index (within-group z score of initial 3 ratings). The mean rating scores assigned by physicians who viewed borderline video performances following exposure to good performances was 2.7 (95% CI, 2.4-3.0) vs 3.4 (95% CI, 3.1-3.7) following exposure to poor performances (difference of 0.67 [95% CI, 0.28-1.07]; P = .001). Borderline videos were categorized as consistent with failing scores in 33 of 60 assessments (55%) in those exposed to good performances and in 15 of 63 assessments (24%) in those exposed to poor performances (P performances compared with 25 of 63 assessments (39.5%) in those exposed to poor performances (P poor

  2. Three-dimensional models of metal-poor stars

    OpenAIRE

    Collet, R.

    2008-01-01

    I present here the main results of recent realistic, 3D, hydrodynamical simulations of convection at the surface of metal-poor red giant stars. I discuss the application of these convection simulations as time-dependent, 3D, hydrodynamical model atmospheres to spectral line formation calculations and abundance analyses. The impact of 3D models on derived elemental abundances is investigated by means of a differential comparison of the line strengths predicted in 3D under the assumption of loc...

  3. 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 ...

  4. 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,…

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

    African Journals Online (AJOL)

    epilepsy is associated with impairment in academic performance,3-7 which may limit .... investigated children and adolescents with mental retardation and so could have ... direct brain damage with resultant cognitive deficits. In addition, an.

  6. 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

  7. Poor Stroop performances in 15-year-old dyslexic teenagers.

    Science.gov (United States)

    Kapoula, Zoï; Lê, Thanh-Thuan; Bonnet, Audrey; Bourtoire, Pauline; Demule, Emilie; Fauvel, Caroline; Quilicci, Catherine; Yang, Qing

    2010-06-01

    The Stroop test enables interference between color naming and reading to be studied. Protopapas et al. (2007) reported more errors in an interference task and longer reaction times in 12.5-year-old dyslexics; also more Stroop interference with lower reading skills. The present study uses a version of the Stroop with four color cards and aims to test interference and flexibility in older dyslexic teenagers. The four cards are: color naming, reading, interference and flexibility. In the latter, subjects have to name the color of the word inhibiting reading except when the word is inside a box. This flexibility task enables the testing of the capacity for cognitive switching between tasks. Ten dyslexics (15.1 +/- 0.7 years old) and fourteen controls (14.3 +/- 1.6 years old) participated in the study. All performed the color naming, the reading, the interference and the flexibility tasks in the same order. Subsequently, they performed a sequence of 60 saccades left-right followed by the interference task. Generally, dyslexic teenagers behaved similarly to non-dyslexics as they showed fewer errors in reading and color than in the interference and flexibility tasks. However, they made more errors and needed more time to accomplish each task than non-dyslexics. The results suggest that the inhibitory and attention processes required by the Stroop test are dysfunctioning even in older dyslexics. In contrast, the study shows no evidence for particular difficulty in the flexibility task, which would constitute an argument against problems with mental switching. Following the execution of saccades, errors in the interference test were significantly reduced for dyslexics, while the time was reduced for both groups. The effects are attributed to visual attention training via saccades.

  8. Poor Performance in Mathematics: Is There a Basis for a Self-Worth Explanation for Women?

    Science.gov (United States)

    Thompson, Ted; Dinnel, Dale L.

    2007-01-01

    The self-worth theory of achievement motivation holds that in situations in which poor performance is likely to reveal low ability, certain students (known as self-worth protective students) intentionally withdraw effort in order to avoid the negative implications of poor performance in terms of damage to self-worth. In this study, evidence of…

  9. [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 < 65%, and being a poor sleeper were associated with increased risk of low performance. Sleep efficiency < 65% was statistically associated with poor 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.

  10. Iron nutrition and premenopausal women: effects of poor iron status on physical and neuropsychological performance.

    Science.gov (United States)

    McClung, James P; Murray-Kolb, Laura E

    2013-01-01

    Iron is a nutritionally essential trace element that functions through incorporation into proteins and enzymes, many of which contribute to physical and neuropsychological performance. Poor iron status, including iron deficiency (ID; diminished iron stores) and iron deficiency anemia (IDA; poor iron stores and diminished hemoglobin), affects billions of people worldwide. This review focuses on physical and neuropsychological outcomes associated with ID and IDA in premenopausal women, as the prevalence of ID and IDA is often greater in premenopausal women than other population demographics. Recent studies addressing the physiological effects of poor iron status on physical performance, including work productivity, voluntary activity, and athletic performance, are addressed. Similarly, the effects of iron status on neurological performance, including cognition, affect, and behavior, are summarized. Nutritional countermeasures for the prevention of poor iron status and the restoration of decrements in performance outcomes are described.

  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. 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 family history of school dysfunction (OR, 2.43; P = .02) and was negatively associated with higher IQ score (OR, 0.90; P 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.

  14. 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.

  15. The association of students requiring remediation in the internal medicine clerkship with poor performance during internship.

    Science.gov (United States)

    Hemann, Brian A; Durning, Steven J; Kelly, William F; Dong, Ting; Pangaro, Louis N; Hemmer, Paul A

    2015-04-01

    To determine whether the Uniformed Services University (USU) system of workplace performance assessment for students in the internal medicine clerkship at the USU continues to be a sensitive predictor of subsequent poor performance during internship, when compared with assessments in other USU third year clerkships. Utilizing Program Director survey results from 2007 through 2011 and U.S. Medical Licensing Examination (USMLE) Step 3 examination results as the outcomes of interest, we compared performance during internship for students who had less than passing performance in the internal medicine clerkship and required remediation, against students whose performance in the internal medicine clerkship was successful. We further analyzed internship ratings for students who received less than passing grades during the same time period on other third year clerkships such as general surgery, pediatrics, obstetrics and gynecology, family medicine, and psychiatry to evaluate whether poor performance on other individual clerkships were associated with future poor performance at the internship level. Results for this recent cohort of graduates were compared with previously published findings. The overall survey response rate for this 5 year cohort was 81% (689/853). Students who received a less than passing grade in the internal medicine clerkship and required further remediation were 4.5 times more likely to be given poor ratings in the domain of medical expertise and 18.7 times more likely to demonstrate poor professionalism during internship. Further, students requiring internal medicine remediation were 8.5 times more likely to fail USMLE Step 3. No other individual clerkship showed any statistically significant associations with performance at the intern level. On the other hand, 40% of students who successfully remediated and did graduate were not identified during internship as having poor performance. Unsuccessful clinical performance which requires remediation in

  16. 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.

  17. 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…

  18. 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.

  19. Evidence that communication impairment in schizophrenia is associated with generalized poor task performance.

    Science.gov (United States)

    Merrill, Anne M; Karcher, Nicole R; Cicero, David C; Becker, Theresa M; Docherty, Anna R; Kerns, John G

    2017-03-01

    People with schizophrenia exhibit wide-ranging cognitive deficits, including slower processing speed and decreased cognitive control. Disorganized speech symptoms, such as communication impairment, have been associated with poor cognitive control task performance (e.g., goal maintenance and working memory). Whether communication impairment is associated with poorer performance on a broader range of non-cognitive control measures is unclear. In the current study, people with schizophrenia (n =51) and non-psychiatric controls (n =26) completed speech interviews allowing for reliable quantitative assessment of communication impairment. Participants also completed multiple goal maintenance and working memory tasks. In addition, we also examined (a) simple measures of processing speed involving highly automatic prepotent responses and (b) a non-cognitive control measure of general task performance. Schizophrenia communication impairment was significantly associated with poor performance in all cognitive domains, with the largest association found with processing speed (r s =-0.52). Further, communication impairment was also associated with the non-cognitive control measure of poor general task performance (r s =-0.43). In contrast, alogia, a negative speech symptom, and positive symptoms were less if at all related to cognitive task performance. Overall, this study suggests that communication impairment in schizophrenia may be associated with relatively generalized poor cognitive task performance. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  20. [Attrition and poor performance in general practice training: age, competence and knowledge play a role].

    Science.gov (United States)

    Vermeulen, Margit I; Kuyvenhoven, Marijke M; Zuithoff, N P A Peter; van der Graaf, Yolanda; Pieters, H M Ron

    2011-01-01

    To investigate which determinants are related to poor performance and forced attrition in the first year residency in general practice (GP). Observational retrospective cohort study. We collected data relating to personal characteristics such as age, sex and clinical experience from residents who started the GP training in Utrecht, the Netherlands, in the period March 2005-August 2007. We also collected competence scores from the domains 'medical expertise', 'doctor-patient communication' and 'professionalism', as well as scores on a national GP knowledge test. The outcome measures were 'poor performance' and 'forced attrition'. Multivariate logistic regression was used to analyse correlations between personal characteristics, competence scores on the 3 domains and knowledge scores in the first trimester on the one hand and poor performance or forced attrition on the other. 215 residents started the GP training. In the first trimester a quarter of the residents had an insufficient score in 1 or more of the domains. Competence scores were mutually correlated, but did not correlate with the knowledge score. 18 residents showed poor performance and 3 were forced to stop their training. Poor performance and forced attrition were correlated with age (adjusted odds ratio (OR): 1.1; 95% CI: 1.0-1.3), insufficient knowledge (adjusted OR: 8.9; 3.0-26.3) and medical expertise (adjusted OR: 2.1; 1.1-4.0) at the beginning of the training. Age, insufficient knowledge of general practice, and insufficient competence in the domain of 'medical expertise' at the beginning of the training are risk factors for poor performance by residents and attrition from their GP training.

  1. 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.

  2. Reliable quantification of BOLD fMRI cerebrovascular reactivity despite poor breath-hold performance.

    Science.gov (United States)

    Bright, Molly G; Murphy, Kevin

    2013-12-01

    Cerebrovascular reactivity (CVR) can be mapped using BOLD fMRI to provide a clinical insight into vascular health that can be used to diagnose cerebrovascular disease. Breath-holds are a readily accessible method for producing the required arterial CO2 increases but their implementation into clinical studies is limited by concerns that patients will demonstrate highly variable performance of breath-hold challenges. This study assesses the repeatability of CVR measurements despite poor task performance, to determine if and how robust results could be achieved with breath-holds in patients. Twelve healthy volunteers were scanned at 3 T. Six functional scans were acquired, each consisting of 6 breath-hold challenges (10, 15, or 20 s duration) interleaved with periods of paced breathing. These scans simulated the varying breath-hold consistency and ability levels that may occur in patient data. Uniform ramps, time-scaled ramps, and end-tidal CO2 data were used as regressors in a general linear model in order to measure CVR at the grey matter, regional, and voxelwise level. The intraclass correlation coefficient (ICC) quantified the repeatability of the CVR measurement for each breath-hold regressor type and scale of interest across the variable task performances. The ramp regressors did not fully account for variability in breath-hold performance and did not achieve acceptable repeatability (ICC0.4). Further analysis of intra-subject CVR variability across the brain (ICCspatial and voxelwise correlation) supported the use of end-tidal CO2 data to extract robust whole-brain CVR maps, despite variability in breath-hold performance. We conclude that the incorporation of end-tidal CO2 monitoring into scanning enables robust, repeatable measurement of CVR that makes breath-hold challenges suitable for routine clinical practice. © 2013.

  3. 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...

  4. 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

    ... applied to local areas for poor performance? 666.420 Section 666.420 Employees' Benefits EMPLOYMENT AND... sanction be applied to local areas for poor performance? (a) If a local area fails to meet the levels of... achieving poor levels of performance; or (3) Requires other appropriate measures designed to improve the...

  5. 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…

  6. 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…

  7. 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

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

    NARCIS (Netherlands)

    Mombarg, Remo; Jelsma, Dorothee; Hartman, Esther

    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

  9. Exercising upper respiratory videoendoscopic evaluation of 100 nonracing performance horses with abnormal respiratory noise and/or poor performance.

    Science.gov (United States)

    Davidson, E J; Martin, B B; Boston, R C; Parente, E J

    2011-01-01

    Although well documented in racehorses, there is paucity in the literature regarding the prevalence of dynamic upper airway abnormalities in nonracing performance horses. To describe upper airway function of nonracing performance horses with abnormal respiratory noise and/or poor performance via exercising upper airway videoendoscopy. Medical records of nonracing performance horses admitted for exercising evaluation with a chief complaint of abnormal respiratory noise and/or poor performance were reviewed. All horses had video recordings of resting and exercising upper airway endoscopy. Relationships between horse demographics, resting endoscopic findings, treadmill intensity and implementation of head and neck flexion during exercise with exercising endoscopic findings were examined. Dynamic upper airway obstructions were observed in 72% of examinations. Head and neck flexion was necessary to obtain a diagnosis in 21 horses. Pharyngeal wall collapse was the most prevalent upper airway abnormality, observed in 31% of the examinations. Complex abnormalities were noted in 27% of the examinations. Resting laryngeal dysfunction was significantly associated with dynamic arytenoid collapse and the odds of detecting intermittent dorsal displacement of the soft palate (DDSP) during exercise in horses with resting DDSP was only 7.7%. Exercising endoscopic observations were different from the resting observations in 54% of examinations. Dynamic upper airway obstructions were common in nonracing performance horses with respiratory noise and/or poor performance. Resting endoscopy was only helpful in determining exercising abnormalities with recurrent laryngeal neuropathy. This study emphasises the importance of exercising endoscopic evaluation in nonracing performance horses with abnormal respiratory noise and/or poor performance for accurate assessment of dynamic upper airway function. © 2010 EVJ Ltd.

  10. 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

  11. 5 CFR 9701.408 - Developing performance and addressing poor performance.

    Science.gov (United States)

    2010-01-01

    ... HUMAN RESOURCES MANAGEMENT SYSTEM (DEPARTMENT OF HOMELAND SECURITY-OFFICE OF PERSONNEL MANAGEMENT) DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM Performance Management § 9701.408... constraints, a supervisor must— (1) Provide employees with the proper tools and technology to do the job; and...

  12. 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.

  13. Social Entrepreneurship : Creating new business models to serve the poor

    OpenAIRE

    Mair, Johanna (Prof.); Seelos, Christian

    2017-01-01

    The term “social entrepreneurship” (SE) is used to refer to the rapidly growing number of organizations that have created models for efficiently catering to basic human needs that existing markets and institutions have failed to satisfy. Social entrepreneurship combines the resourcefulness of traditional entrepreneurship with a mission to change society. One social entrepreneur, Ibrahim Abouleish, recently received the “Alternative Nobel Prize” for his Sekem initiative; in 2004, e-Bay founder...

  14. Models of alien species richness show moderate predictive accuracy and poor transferability

    Directory of Open Access Journals (Sweden)

    César Capinha

    2018-06-01

    Full Text Available Robust predictions of alien species richness are useful to assess global biodiversity change. Nevertheless, the capacity to predict spatial patterns of alien species richness remains largely unassessed. Using 22 data sets of alien species richness from diverse taxonomic groups and covering various parts of the world, we evaluated whether different statistical models were able to provide useful predictions of absolute and relative alien species richness, as a function of explanatory variables representing geographical, environmental and socio-economic factors. Five state-of-the-art count data modelling techniques were used and compared: Poisson and negative binomial generalised linear models (GLMs, multivariate adaptive regression splines (MARS, random forests (RF and boosted regression trees (BRT. We found that predictions of absolute alien species richness had a low to moderate accuracy in the region where the models were developed and a consistently poor accuracy in new regions. Predictions of relative richness performed in a superior manner in both geographical settings, but still were not good. Flexible tree ensembles-type techniques (RF and BRT were shown to be significantly better in modelling alien species richness than parametric linear models (such as GLM, despite the latter being more commonly applied for this purpose. Importantly, the poor spatial transferability of models also warrants caution in assuming the generality of the relationships they identify, e.g. by applying projections under future scenario conditions. Ultimately, our results strongly suggest that predictability of spatial variation in richness of alien species richness is limited. The somewhat more robust ability to rank regions according to the number of aliens they have (i.e. relative richness, suggests that models of aliens species richness may be useful for prioritising and comparing regions, but not for predicting exact species numbers.

  15. QUALITY OF LIFE AND HEALTH SELF-PERCEPTION IN CHILDREN WITH POOR SCHOOL PERFORMANCE.

    Science.gov (United States)

    Rezende, Bárbara Antunes; Lemos, Stela Maris Aguiar; Medeiros, Adriane Mesquita de

    2017-01-01

    To examine the association between quality of life and health self-perception of children with poor school performance, considering sociodemographic factors. An analytical, observational, cross-sectional study was conducted with 99 children aged 7 to 12 years receiving specialized educational assistance. Parents and legal guardians answered questions concerning the sociodemographic profile. For an assessment of the quality of life and proposed domains (autonomy, functioning, leisure, and family), the children completed the Autoquestionnarie Qualité de Vie Enfant Imagé (AUQEI) and answered a question concerning their self-perceived health. Data were analyzed using multiple linear regression, considering a 5% significance level. Among the evaluated children, 69 (69.7%) male participants with mean age of 8.7±1.5, 27% self-assessed their health status as poor/very poor, and 36.4% of the children reported having impaired quality of life. As for the domains assessed by AUQEI, there was statistical significance in the associations between family with age, autonomy with economic classification, and leisure and functioning with self-perceived health. The quality of life of children with academic underachievement is associated with their health self-perception and sociodemographic characteristics.

  16. 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

    To explore the link between companies investing in the health and well-being programs of their employees and stock market performance. 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. 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%. 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.

  17. 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

  18. 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

  19. 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

  20. Exercising videoendoscopic evaluation of 45 horses with respiratory noise and/or poor performance after laryngoplasty.

    Science.gov (United States)

    Davidson, Elizabeth J; Martin, Benson B; Rieger, Randall H; Parente, Eric J

    2010-12-01

    To (1) assess upper airway function by videoendoscopy in horses performing poorly after laryngoplasty and (2) establish whether dynamic collapse of the left arytenoid can be predicted by the degree of resting postsurgical abduction. Case series. Horses that had left laryngoplasty (n=45). Medical records (June 1993-December 2007) of horses evaluated for abnormal respiratory noise and/or poor performance after laryngoplasty were reviewed. Horses with video recordings of resting and exercising upper airway endoscopy were included and postsurgical abduction categorized. Horses with immediate postoperative endoscopy recordings were also evaluated and postsurgical abduction categorized. Relationships between resting postsurgical abduction and historical information with exercising endoscopic findings were examined. Dynamic collapse of the left arytenoid cartilage was probable in horses with no postsurgical abduction and could not be predicted in horses with grade 3 or 4 postsurgical abduction. Respiratory noise was associated with upper airway obstruction but was not specific for arytenoid collapse. Most horses with a left vocal fold had billowing of the fold during exercise. Other forms of dynamic collapse involved the right vocal fold, aryepiglottic folds, corniculate process of left arytenoid cartilage, dorsal displacement of soft palate, and pharyngeal collapse. Complex obstructions were observed in most examinations and in all horses with exercising collapse of the left arytenoid cartilage. There was no relationship between exercising collapse of the left arytenoid cartilage and grade 3 or 4 postsurgical abduction but was likely in horses with no abduction. © Copyright 2010 by The American College of Veterinary Surgeons.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Ion thruster performance model

    International Nuclear Information System (INIS)

    Brophy, J.R.

    1984-01-01

    A model of ion thruster performance is developed for high flux density cusped magnetic field thruster designs. This model is formulated in terms of the average energy required to produce an ion in the discharge chamber plasma and the fraction of these ions that are extracted to form the beam. The direct loss of high energy (primary) electrons from the plasma to the anode is shown to have a major effect on thruster performance. The model provides simple algebraic equations enabling one to calculate the beam ion energy cost, the average discharge chamber plasma ion energy cost, the primary electron density, the primary-to-Maxwellian electron density ratio and the Maxwellian electron temperature. Experiments indicate that the model correctly predicts the variation in plasma ion energy cost for changes in propellant gas (Ar, Kr, and Xe), grid transparency to neutral atoms, beam extraction area, discharge voltage, and discharge chamber wall temperature

  10. 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

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

    Science.gov (United States)

    Vitor-Silva, Sheila; Reyes-Lecca, Roberto C; Pinheiro, Tamam RA; Lacerda, Marcus VG

    2009-01-01

    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. vivax is responsible for

  12. Base Station Performance Model

    OpenAIRE

    Walsh, Barbara; Farrell, Ronan

    2005-01-01

    At present the testing of power amplifiers within base station transmitters is limited to testing at component level as opposed to testing at the system level. While the detection of catastrophic failure is possible, that of performance degradation is not. This paper proposes a base station model with respect to transmitter output power with the aim of introducing system level monitoring of the power amplifier behaviour within the base station. Our model reflects the expe...

  13. Performance modeling of Beamlet

    International Nuclear Information System (INIS)

    Auerbach, J.M.; Lawson, J.K.; Rotter, M.D.; Sacks, R.A.; Van Wonterghem, B.W.; Williams, W.H.

    1995-01-01

    Detailed modeling of beam propagation in Beamlet has been made to predict system performance. New software allows extensive use of optical component characteristics. This inclusion of real optical component characteristics has resulted in close agreement between calculated and measured beam distributions

  14. Low motor performance scores among overweight children: poor coordination or morphological constraints?

    Science.gov (United States)

    Chivers, Paola; Larkin, Dawne; Rose, Elizabeth; Beilin, Lawrence; Hands, Beth

    2013-10-01

    This study examined whether lower motor performance scores can be full attributed to poor coordination, or whether weight related morphological constraints may also affect motor performance. Data for 666 children and adolescents from the longitudinal Western Australian Pregnancy Cohort (Raine) Study were grouped into normal weight, overweight and obese categories based on the International Obesity Task Force cut points. Participants completed the 10-item McCarron Assessment of Neuromuscular Development (MAND) at the 10 and 14 year follow-up. The prevalence of overweight and obese participants classified with mild or moderate motor difficulties was not different from the normal weight group at 10 years (χ2 = 5.8 p = .215), but higher at 14 years (χ2 = 11.3 p = .023). There were no significant differences in overall motor performance scores between weight status groups at 10 years, but at 14 years, the normal weight group achieved better scores than the obese group (pobese groups on the jump task at 10 (pmotor competence are appropriate for an increasingly overweight and obese population. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. 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...

  16. ATR performance modeling concepts

    Science.gov (United States)

    Ross, Timothy D.; Baker, Hyatt B.; Nolan, Adam R.; McGinnis, Ryan E.; Paulson, Christopher R.

    2016-05-01

    Performance models are needed for automatic target recognition (ATR) development and use. ATRs consume sensor data and produce decisions about the scene observed. ATR performance models (APMs) on the other hand consume operating conditions (OCs) and produce probabilities about what the ATR will produce. APMs are needed for many modeling roles of many kinds of ATRs (each with different sensing modality and exploitation functionality combinations); moreover, there are different approaches to constructing the APMs. Therefore, although many APMs have been developed, there is rarely one that fits a particular need. Clarified APM concepts may allow us to recognize new uses of existing APMs and identify new APM technologies and components that better support coverage of the needed APMs. The concepts begin with thinking of ATRs as mapping OCs of the real scene (including the sensor data) to reports. An APM is then a mapping from explicit quantized OCs (represented with less resolution than the real OCs) and latent OC distributions to report distributions. The roles of APMs can be distinguished by the explicit OCs they consume. APMs used in simulations consume the true state that the ATR is attempting to report. APMs used online with the exploitation consume the sensor signal and derivatives, such as match scores. APMs used in sensor management consume neither of those, but estimate performance from other OCs. This paper will summarize the major building blocks for APMs, including knowledge sources, OC models, look-up tables, analytical and learned mappings, and tools for signal synthesis and exploitation.

  17. Effect of exposure to good vs poor medical trainee performance on attending physician ratings of subsequent performances

    OpenAIRE

    Yeates, Peter; O'Neill, Paul; Mann, Karen; Eva, Kevin W.

    2012-01-01

    Context: Competency-based models of education require assessments to be based on individuals' capacity to perform, yet the nature of human judgment may fundamentally limit the extent to which such assessment is accurately possible. Objective: To determine whether recent observations of the Mini Clinical Evaluation Exercise (Mini-CEX) performance of postgraduate year 1 physicians influence raters' scores of subsequent performances, consistent with either anchoring bias (scores biased similar t...

  18. 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. PMID:24151475

  19. 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.

  20. 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.

  1. 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.

  2. Singing with yourself: evidence for an inverse modeling account of poor-pitch singing.

    Science.gov (United States)

    Pfordresher, Peter Q; Mantell, James T

    2014-05-01

    Singing is a ubiquitous and culturally significant activity that humans engage in from an early age. Nevertheless, some individuals - termed poor-pitch singers - are unable to match target pitches within a musical semitone while singing. In the experiments reported here, we tested whether poor-pitch singing deficits would be reduced when individuals imitate recordings of themselves as opposed to recordings of other individuals. This prediction was based on the hypothesis that poor-pitch singers have not developed an abstract "inverse model" of the auditory-vocal system and instead must rely on sensorimotor associations that they have experienced directly, which is true for sequences an individual has already produced. In three experiments, participants, both accurate and poor-pitch singers, were better able to imitate sung recordings of themselves than sung recordings of other singers. However, this self-advantage was enhanced for poor-pitch singers. These effects were not a byproduct of self-recognition (Experiment 1), vocal timbre (Experiment 2), or the absolute pitch of target recordings (i.e., the advantage remains when recordings are transposed, Experiment 3). Results support the conceptualization of poor-pitch singing as an imitative deficit resulting from a deficient inverse model of the auditory-vocal system with respect to pitch. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. 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...... that a hypothetical poor economy with a high level of social trust, when beginning at a relative income level of 10%, may need about 150 years to reach 50% of the income level of the leading countries. However, the process of catching up may only begin after 150 years of relative stagnation for a hypothetical poor...

  4. 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...

  5. 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.

  6. 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...

  7. Using Predictive Modelling to Identify Students at Risk of Poor University Outcomes

    Science.gov (United States)

    Jia, Pengfei; Maloney, Tim

    2015-01-01

    Predictive modelling is used to identify students at risk of failing their first-year courses and not returning to university in the second year. Our aim is twofold. Firstly, we want to understand the factors that lead to poor first-year experiences at university. Secondly, we want to develop simple, low-cost tools that would allow universities to…

  8. Getting off on the Wrong Foot: Longitudinal Effects of Hispanic Students' Stability Attributions Following Poor Initial Test Performance

    Science.gov (United States)

    Cox, Cody B.; Yang, Yan

    2012-01-01

    Though studies have established that following poor performance, attributions to stable causes affect the performance of minority students, few studies have explored the impact of stability attributions over time. This study explored attributions following initial failure among a predominantly Hispanic student population. We measured students'…

  9. 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.

  10. Sustainable solar home systems model: Applying lessons from Bangladesh to Myanmar's rural poor

    DEFF Research Database (Denmark)

    Newcombe, Alex; Ackom, Emmanuel

    2017-01-01

    Myanmar's rural population has very low access to electricity, mainly due to low disposal income and the remoteness of communities. This paper attempts to test the potential applicability of Grameen Shakti-Infrastructure Development Company Limited (IDCOL), which is a Bangladeshi public private...... partnership microfinance model, to rural Myanmar towards enhanced solar home systems (SHS) deployment. Rural poor are enabled by this microfinancing scheme to own SHSs in a few years for as low as US$6.40 per month. The objectives of this paper are to assess the experience of Grameen Shakti-IDCOL and other...... similar projects for invaluable lessons, identify barriers to sustainable electrification for Myanmar's rural poor and to apply these lessons learned to overcome barriers by developing policy recommendations for sustainable electrification for rural poor in Myanmar. Recommendations are provided suggesting...

  11. 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.

  12. 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.

  13. Eye-Movement Patterns and Reader Characteristics of Students with Good and Poor Performance When Reading Scientific Text with Diagrams

    Science.gov (United States)

    Jian, Yu-Cin

    2017-01-01

    This study investigated the cognitive processes and reader characteristics of sixth graders who had good and poor performance when reading scientific text with diagrams. We first measured the reading ability and reading self-efficacy of sixth-grade participants, and then recorded their eye movements while they were reading an illustrated…

  14. 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

    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....

  15. Predictive performance models and multiple task performance

    Science.gov (United States)

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

    1989-01-01

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

  16. 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.

  17. Measurement error and timing of predictor values for multivariable risk prediction models are poorly reported.

    Science.gov (United States)

    Whittle, Rebecca; Peat, George; Belcher, John; Collins, Gary S; Riley, Richard D

    2018-05-18

    Measurement error in predictor variables may threaten the validity of clinical prediction models. We sought to evaluate the possible extent of the problem. A secondary objective was to examine whether predictors are measured at the intended moment of model use. A systematic search of Medline was used to identify a sample of articles reporting the development of a clinical prediction model published in 2015. After screening according to a predefined inclusion criteria, information on predictors, strategies to control for measurement error and intended moment of model use were extracted. Susceptibility to measurement error for each predictor was classified into low and high risk. Thirty-three studies were reviewed, including 151 different predictors in the final prediction models. Fifty-one (33.7%) predictors were categorised as high risk of error, however this was not accounted for in the model development. Only 8 (24.2%) studies explicitly stated the intended moment of model use and when the predictors were measured. Reporting of measurement error and intended moment of model use is poor in prediction model studies. There is a need to identify circumstances where ignoring measurement error in prediction models is consequential and whether accounting for the error will improve the predictions. Copyright © 2018. Published by Elsevier Inc.

  18. Modeling wind energy potential in a data-poor region: A geographic information systems model for Iraq

    Science.gov (United States)

    Khayyat, Abdulkareem Hawta Abdullah Kak Ahmed

    Scope and Method of Study: Most developing countries, including Iraq, have very poor wind data. Existing wind speed measurements of poor quality may therefore be a poor guide to where to look for the best wind resources. The main focus of this study is to examine how effectively a GIS spatial model estimates wind power potential in regions where high-quality wind data are very scarce, such as Iraq. The research used a mixture of monthly and hourly wind data from 39 meteorological stations. The study applied spatial analysis statistics and GIS techniques in modeling wind power potential. The model weighted important human, environmental and geographic factors that impact wind turbine siting, such as roughness length, land use⪉nd cover type, airport locations, road access, transmission lines, slope and aspect. Findings and Conclusions: The GIS model provided estimations for wind speed and wind power density and identified suitable areas for wind power projects. Using a high resolution (30*30m) digital elevation model DEM improved the GIS wind suitability model. The model identified areas suitable for wind farm development on different scales. The model showed that there are many locations available for large-scale wind turbines in the southern part of Iraq. Additionally, there are many places in central and northern parts (Kurdistan Region) for smaller scale wind turbine placement.

  19. Poor Physical Performance is Associated with Obesity Among University Students in China

    OpenAIRE

    Du, Tianhua; Zhu, Ergang; Jiao, Suhua

    2017-01-01

    Background The aim of this study was to explore the relationship between physical performance and BMI (body mass index) of university students in China. Material/Methods We conducted a cross-sectional study evaluating the physical performance and BMI of university students. BMI was calculated based on height and weight. Overweight and obesity were defined by the Working Group on Obesity references in China. Results A total of 2313 participants (978 males and 1335 females) were recruited in ou...

  20. Model-independent separation of poorly resolved hypperfine split spectra by a linear combination method

    International Nuclear Information System (INIS)

    Nagy, D.L.; Dengler, J.; Ritter, G.

    1988-01-01

    A model-independent evaluation of the components of poorly resolved Moessbauer spectra based on a linear combination method is possible if there is a parameter as a function of which the shape of the individual components do not but their intensities do change and the dependence of the intensities on this parameter is known. The efficiency of the method is demonstrated on the example of low temperature magnetically split spectra of the high-T c superconductor YBa 2 (Cu 0.9 Fe 0 .1 ) 3 O 7-y . (author)

  1. On the temperatures, colours, and ages of metal-poor stars predicted by stellar models

    International Nuclear Information System (INIS)

    Van den Berg, D A

    2008-01-01

    Most (but not all) of the investigations that have derived the effective temperatures of metal-poor, solar-neighbourhood field stars, from analyses of their spectra or from the infrared flux method, favour a T eff scale that is ∼100-120 K cooler than that given by stellar evolutionary models. This seems to be at odds with photometric results, given that the application of current colour-T eff relations to the observed subdwarf colours suggests a preference for hotter temperatures. Moreover, the predicted temperatures for main-sequence stars at the lowest metallicities ([Fe/H] eff for them unless some fundamental modification is made to the adopted physics. No such problems are found if the temperatures of metal-poor field stars are ∼100-120 K warmer than most determinations. In this case, stellar models would appear to provide consistent interpretations of both field and globular cluster (GC) stars of low metallicity. However, this would imply, e.g. that M 92 has an [Fe/H] value of approximately - 2.2, which is obtained from analyses of Fe I lines, instead of approximately equal to - 2.4, as derived from Fe II lines (and favoured by studies of three-dimensional model atmospheres). Finally, the age of the local, Population II subgiant HD 140283 (and GCs having similar metal abundances) is estimated to be ∼13 Gyr, if diffusive processes are taken into account.

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. Increased needle nitrogen contents did not improve shoot photosynthetic performance of mature nitrogen-poor Scots pine trees

    Directory of Open Access Journals (Sweden)

    Lasse Tarvainen

    2016-07-01

    Full Text Available Numerous studies have shown that temperate and boreal forests are limited by nitrogen (N availability. However, few studies have provided a detailed account of how carbon (C acquisition of such forests reacts to increasing N supply. We combined measurements of needle-scale biochemical photosynthetic capacities and continuous observations of shoot-scale photosynthetic performance from several canopy positions with simple mechanistic modelling to evaluate the photosynthetic responses of mature N-poor boreal Pinus sylvestris to N fertilization. The measurements were carried out in August 2013 on 90-year-old pine trees growing at Rosinedalsheden research site in northern Sweden. In spite of a nearly doubling of needle N content in response to the fertilization, no effect on the long-term shoot-scale C uptake was recorded. This lack of N-effect was due to strong light limitation of photosynthesis in all investigated canopy positions. The effect of greater N availability on needle photosynthetic capacities was also constrained by development of foliar P deficiency following N addition. Thus, P deficiency and accumulation of N in arginine appeared to contribute towards lower shoot-scale nitrogen-use efficiency in the fertilized trees, thereby additionally constraining tree-scale responses to increasing N availability. On the whole our study suggests that the C uptake response of the studied N-poor boreal P. sylvestris stand to enhanced N availability is constrained by the efficiency with which the additional N is utilized. This efficiency, in turn, depends on the ability of the trees to use the greater N availability for additional light capture. For stands that have not reached canopy closure, increase in leaf area following N fertilization would be the most effective way for improving light capture and C uptake while for mature stands an increased leaf area may have a rather limited effect on light capture owing to increased self-shading. This raises

  7. Increased Needle Nitrogen Contents Did Not Improve Shoot Photosynthetic Performance of Mature Nitrogen-Poor Scots Pine Trees.

    Science.gov (United States)

    Tarvainen, Lasse; Lutz, Martina; Räntfors, Mats; Näsholm, Torgny; Wallin, Göran

    2016-01-01

    Numerous studies have shown that temperate and boreal forests are limited by nitrogen (N) availability. However, few studies have provided a detailed account of how carbon (C) acquisition of such forests reacts to increasing N supply. We combined measurements of needle-scale biochemical photosynthetic capacities and continuous observations of shoot-scale photosynthetic performance from several canopy positions with simple mechanistic modeling to evaluate the photosynthetic responses of mature N-poor boreal Pinus sylvestris to N fertilization. The measurements were carried out in August 2013 on 90-year-old pine trees growing at Rosinedalsheden research site in northern Sweden. In spite of a nearly doubling of needle N content in response to the fertilization, no effect on the long-term shoot-scale C uptake was recorded. This lack of N-effect was due to strong light limitation of photosynthesis in all investigated canopy positions. The effect of greater N availability on needle photosynthetic capacities was also constrained by development of foliar phosphorus (P) deficiency following N addition. Thus, P deficiency and accumulation of N in arginine appeared to contribute toward lower shoot-scale nitrogen-use efficiency in the fertilized trees, thereby additionally constraining tree-scale responses to increasing N availability. On the whole our study suggests that the C uptake response of the studied N-poor boreal P. sylvestris stand to enhanced N availability is constrained by the efficiency with which the additional N is utilized. This efficiency, in turn, depends on the ability of the trees to use the greater N availability for additional light capture. For stands that have not reached canopy closure, increase in leaf area following N fertilization would be the most effective way for improving light capture and C uptake while for mature stands an increased leaf area may have a rather limited effect on light capture owing to increased self-shading. This raises the

  8. Matching Faces to Photographs: Poor Performance in Eyewitness Memory (without the Memory)

    Science.gov (United States)

    Megreya, Ahmed M.; Burton, A. Mike

    2008-01-01

    Eyewitness memory is known to be fallible. We describe 3 experiments that aim to establish baseline performance for recognition of unfamiliar faces. In Experiment 1, viewers were shown live actors or photos (targets), and then immediately presented with arrays of 10 faces (test items). Asked whether the target was present among the test items, and…

  9. 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…

  10. Managing poorly performing clinicians: health care providers' willingness to pay for independent help.

    Science.gov (United States)

    Watson, Verity; Sussex, Jon; Ryan, Mandy; Tetteh, Ebenezer

    2012-03-01

    To determine the willingness to pay (WTP) of senior managers in the UK National Health Service (NHS) for services to help manage performance concerns with doctors, dentists and pharmacists. A discrete choice experiment (DCE) was used to elicit senior managers' preferences for a support service to help manage clinical performance concerns. The DCE was based on: a literature review; interviews with support service providers and clinical professional bodies; and discussion groups with managers. From the DCE responses, we estimate marginal WTP for aspects of support services. 451 NHS managers completed the DCE questionnaire. NHS managers are willing to pay for: advice, 'facilitation', and behavioural, health, clinical and organisational assessments. Telephone advice with written confirmation was valued most highly. NHS managers were willing to pay £161.56 (CI: £160.81-£162.32) per year per whole time equivalent doctor, dentist or pharmacist, for support to help manage clinical performance concerns. Marginal WTP varied across respondent subgroups but was always positive. Health care managers valued help in managing the clinicians' performance, and were willing to pay for it from their organisations' limited funds. Their WTP exceeds the current cost of a UK body providing similar support. Establishing a central body to provide such services across a health care system, with the associated economies of scale including cumulative experience, is an option that policy makers should consider seriously. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  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. 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.

  13. 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.

  14. Poor Physical Performance is Associated with Obesity Among University Students in China.

    Science.gov (United States)

    Du, Tianhua; Zhu, Ergang; Jiao, Suhua

    2017-05-05

    BACKGROUND The aim of this study was to explore the relationship between physical performance and BMI (body mass index) of university students in China. MATERIAL AND METHODS We conducted a cross-sectional study evaluating the physical performance and BMI of university students. BMI was calculated based on height and weight. Overweight and obesity were defined by the Working Group on Obesity references in China. RESULTS A total of 2313 participants (978 males and 1335 females) were recruited in our study. The mean value of the 50-meter dash and standing long jump in male students was higher than in female students (Pobesity) and obesity for male students were 17.9% and 4.2%, respectively, and 5.1% and 0.5%, respectively, for female university students. BMI was weakly positively associated with the 50-meter dash score, but was negatively associated with the score for standing long jump and pull-ups. CONCLUSIONS Our study suggested that overweight and obesity are associated with physical performance of university students, especially in male students. University students should exercise more to improve physical health.

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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 (pperforming well on the DRT tests. CONCLUSION: Old, memory...

  20. 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.)

  1. 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

  2. Presence of neuropathic pain may explain poor performances on olfactory testing in diabetes mellitus patients.

    Science.gov (United States)

    Brady, Shauna; Lalli, Paul; Midha, Nisha; Chan, Ayechen; Garven, Alexandra; Chan, Cynthia; Toth, Cory

    2013-07-01

    Olfactory dysfunction in neurodegenerative conditions such as Parkinson's syndrome and Alzheimer's disease can hallmark disease onset. We hypothesized that patients with diabetes mellitus, a condition featuring peripheral and central neurodegeneration, would have decreased olfaction abilities. We examined participants with diabetic peripheral neuropathy, participants with diabetes without diabetic peripheral neuropathy, and control participants in blinded fashion using standardized Sniffin' Sticks. Diabetic peripheral neuropathy severity was quantified using the Utah Early Neuropathy Scale. Further subcategorization of diabetic peripheral neuropathy based on presence of neuropathic pain was performed with Douleur Neuropathique 4 Questionnaires. Participants with diabetes had decreased olfactory sensitivity, impaired olfactory discrimination abilities, and reduced odor identification skills when compared with controls. However, loss of olfaction ability was, at least partially, attributed to presence of neuropathic pain on subcategory assessment, although pain severity was not associated with dysfunction. Those participants with diabetes without diabetic peripheral neuropathy and those with diabetic peripheral neuropathy without neuropathic pain had similar olfactory function as controls in general. The presence of neuropathic pain, associated with limited attention and concentration, may explain at least a portion of the olfactory dysfunction witnessed in the diabetic patient population.

  3. The Poor Altmetric Performance of Publications Authored by Researchers in Mainland China

    Directory of Open Access Journals (Sweden)

    Xianwen Wang

    2016-10-01

    Full Text Available China’s scientific output has risen precipitously over the past decade; it is now the world’s second-largest producer of scientific papers, behind only the United States. The quality of China’s research is also on the rise (Van Noorden, 2016. The online visibility and impact of China’s research are also important issues worth exploring. In this study, we investigate the altmetric performance of publications in the field of Biotechnology and Applied Microbiology and published by authors from Chinese affiliations. We find that papers published by those authors from Chinese affiliations have much lower visibility on the social web than articles from other countries, when there is no significant difference for the citations. Fewer of China’s publications get tweeted, and those tweeted publications attract less social attention. A geographical analysis of tweeters shows that scholarly articles get most of their social attention from the authors’ home countries, a finding that is also confirmed by correlation and regression analysis. This situation, which is unfavorable for researchers from Chinese affiliations, is caused, in part, by the inaccessibility of mainstream social networking platforms in mainland China.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Demand Creation for Polio Vaccine in Persistently Poor-Performing Communities of Northern Nigeria: 2013-2014.

    Science.gov (United States)

    Warigon, Charity; Mkanda, Pascal; Muhammed, Ado; Etsano, Andrew; Korir, Charles; Bawa, Samuel; Gali, Emmanuel; Nsubuga, Peter; Erbeto, Tesfaya B; Gerlong, George; Banda, Richard; Yehualashet, Yared G; Vaz, Rui G

    2016-05-01

    Poliomyelitis remains a global threat despite availability of oral polio vaccine (OPV), proven to reduce the burden of the paralyzing disease. In Nigeria, children continue to miss the opportunity to be fully vaccinated, owing to factors such as unmet health needs and low uptake in security-compromised and underserved communities. We describe the implementation and evaluation of several activities to create demand for polio vaccination in persistently poor-performing local government areas (LGAs). We assessed the impact of various polio-related interventions, to measure the contribution of demand creation activities in 77 LGAs at very high risk for polio, located across 10 states in northern Nigeria. Interventions included provision of commodities along with the polio vaccine. There was an increasing trend in the number of children reached by different demand creation interventions. A total of 4 819 847 children were vaccinated at health camps alone. There was a reduction in the number of wards in which >10% of children were missed by supplementary immunization activities due to noncompliance with vaccination recommendations, a rise in the proportion of children who received ≥4 OPV doses, and a decrease in the proportion of children who were underimmunized or unimmunized. Demand creation interventions increased the uptake of polio vaccines in persistently poor-performing high-risk communities in northern Nigeria during September 2013-November 2014. © 2016 World Health Organization; licensee Oxford Journals.

  10. Comorbidity predicts poor prognosis in nasopharyngeal carcinoma: Development and validation of a predictive score model

    International Nuclear Information System (INIS)

    Guo, Rui; Chen, Xiao-Zhong; Chen, Lei; Jiang, Feng; Tang, Ling-Long; Mao, Yan-Ping; Zhou, Guan-Qun; Li, Wen-Fei; Liu, Li-Zhi; Tian, Li; Lin, Ai-Hua; Ma, Jun

    2015-01-01

    Background and purpose: The impact of comorbidity on prognosis in nasopharyngeal carcinoma (NPC) is poorly characterized. Material and methods: Using the Adult Comorbidity Evaluation-27 (ACE-27) system, we assessed the prognostic value of comorbidity and developed, validated and confirmed a predictive score model in a training set (n = 658), internal validation set (n = 658) and independent set (n = 652) using area under the receiver operating curve analysis. Results: Comorbidity was present in 40.4% of 1968 patients (mild, 30.1%; moderate, 9.1%; severe, 1.2%). Compared to an ACE-27 score ⩽1, patients with an ACE-27 score >1 in the training set had shorter overall survival (OS) and disease-free survival (DFS) (both P < 0.001), similar results were obtained in the other sets (P < 0.05). In multivariate analysis, ACE-27 score was a significant independent prognostic factor for OS and DFS. The combined risk score model including ACE-27 had superior prognostic value to TNM stage alone in the internal validation set (0.70 vs. 0.66; P = 0.02), independent set (0.73 vs. 0.67; P = 0.002) and all patients (0.71 vs. 0.67; P < 0.001). Conclusions: Comorbidity significantly affects prognosis, especially in stages II and III, and should be incorporated into the TNM staging system for NPC. Assessment of comorbidity may improve outcome prediction and help tailor individualized treatment

  11. Modeling the Release Kinetics of Poorly Water-Soluble Drug Molecules from Liposomal Nanocarriers

    Directory of Open Access Journals (Sweden)

    Stephan Loew

    2011-01-01

    Full Text Available Liposomes are frequently used as pharmaceutical nanocarriers to deliver poorly water-soluble drugs such as temoporfin, cyclosporine A, amphotericin B, and paclitaxel to their target site. Optimal drug delivery depends on understanding the release kinetics of the drug molecules from the host liposomes during the journey to the target site and at the target site. Transfer of drugs in model systems consisting of donor liposomes and acceptor liposomes is known from experimental work to typically exhibit a first-order kinetics with a simple exponential behavior. In some cases, a fast component in the initial transfer is present, in other cases the transfer is sigmoidal. We present and analyze a theoretical model for the transfer that accounts for two physical mechanisms, collisions between liposomes and diffusion of the drug molecules through the aqueous phase. Starting with the detailed distribution of drug molecules among the individual liposomes, we specify the conditions that lead to an apparent first-order kinetic behavior. We also discuss possible implications on the transfer kinetics of (1 high drug loading of donor liposomes, (2 attractive interactions between drug molecules within the liposomes, and (3 slow transfer of drugs between the inner and outer leaflets of the liposomes.

  12. 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.

  13. 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.

  14. Methylphenidate enhances cognitive performance in adults with poor baseline capacities regardless of attention-deficit/hyperactivity disorder diagnosis.

    Science.gov (United States)

    Agay, Nirit; Yechiam, Eldad; Carmel, Ziv; Levkovitz, Yechiel

    2014-04-01

    We compare the view that the effect of methylphenidate (MPH) is selective to individuals with attention-deficit/hyperactivity disorder (ADHD) with an alternative approach suggesting that its effect is more prominent for individuals with weak baseline capacities in relevant cognitive tasks. To evaluate theses 2 approaches, we administered sustained attention, working memory, and decision-making tasks to 20 ADHD adults and 19 control subjects, using a within-subject placebo-controlled design. The results demonstrated no main effects of MPH in the decision-making tasks. In the sustained attention and working-memory tasks, MPH enhanced performance of both ADHD and non-ADHD adults to a similar extent compared with placebo. Hence, the effect of MPH was not selective to ADHD adults. In addition, those benefitting most from MPH in all 3 task domains tended to be individuals with poor task performance. However, in most tasks, individuals whose performance was impaired by MPH were not necessarily better (or worse) performers. The findings suggest that the administration of MPH to adults with ADHD should consider not only clinical diagnosis but also their functional (performance-based) profile.

  15. 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

  16. Families at risk of poor parenting: a model for service delivery, assessment, and intervention.

    Science.gov (United States)

    Ayoub, C; Jacewitz, M M

    1982-01-01

    The At Risk Parent Child Program is a multidisciplinary network agency designed for the secondary prevention of poor parenting and the extremes of child abuse and neglect. This model system of service delivery emphasizes (1) the coordination of existing community resources to access a target population of families at risk of parenting problems, (2) the provision of multiple special services in a neutral location (ambulatory pediatric clinic), and (3) the importance of intensive individual contact with a clinical professional who serves as primary therapist, social advocate and service coordinator for client families. Identification and assessment of families is best done during prenatal and perinatal periods. Both formal and informal procedures for screening for risk factors are described, and a simple set of at risk criteria for use by hospital nursing staff is provided. Preventive intervention strategies include special medical, psychological, social and developmental services, offered in an inpatient; outpatient, or in-home setting. Matching family needs to modality and setting of treatment is a major program concern. All direct services to at risk families are supplied by professionals employed within existing local agencies (hospital, public health department, state guidance center, and medical school pediatric clinic). Multiple agency involvement allows a broad-based screening capacity which allows thousands of families routine access to program services. The administrative center of the network stands as an independent, community-funded core which coordinates and monitors direct clinical services, and provides local political advocacy for families at risk of parenting problems.

  17. Performability Modelling Tools, Evaluation Techniques and Applications

    NARCIS (Netherlands)

    Haverkort, Boudewijn R.H.M.

    1990-01-01

    This thesis deals with three aspects of quantitative evaluation of fault-tolerant and distributed computer and communication systems: performability evaluation techniques, performability modelling tools, and performability modelling applications. Performability modelling is a relatively new

  18. Creating a model to detect dairy cattle farms with poor welfare using a national database.

    Science.gov (United States)

    Krug, C; Haskell, M J; Nunes, T; Stilwell, G

    2015-12-01

    The objective of this study was to determine whether dairy farms with poor cow welfare could be identified using a national database for bovine identification and registration that monitors cattle deaths and movements. The welfare of dairy cattle was assessed using the Welfare Quality(®) protocol (WQ) on 24 Portuguese dairy farms and on 1930 animals. Five farms were classified as having poor welfare and the other 19 were classified as having good welfare. Fourteen million records from the national cattle database were analysed to identify potential welfare indicators for dairy farms. Fifteen potential national welfare indicators were calculated based on that database, and the link between the results on the WQ evaluation and the national cattle database was made using the identification code of each farm. Within the potential national welfare indicators, only two were significantly different between farms with good welfare and poor welfare, 'proportion of on-farm deaths' (ptree based on two variables, 'proportion of on-farm deaths' and 'calving-to-calving interval', and it was able to correctly identify 70% and 79% of the farms classified as having poor and good welfare, respectively. The national cattle database analysis could be useful in helping official veterinary services in detecting farms that have poor welfare and also in determining which welfare indicators are poor on each particular farm. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. 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.

  20. Data management system performance modeling

    Science.gov (United States)

    Kiser, Larry M.

    1993-01-01

    This paper discusses analytical techniques that have been used to gain a better understanding of the Space Station Freedom's (SSF's) Data Management System (DMS). The DMS is a complex, distributed, real-time computer system that has been redesigned numerous times. The implications of these redesigns have not been fully analyzed. This paper discusses the advantages and disadvantages for static analytical techniques such as Rate Monotonic Analysis (RMA) and also provides a rationale for dynamic modeling. Factors such as system architecture, processor utilization, bus architecture, queuing, etc. are well suited for analysis with a dynamic model. The significance of performance measures for a real-time system are discussed.

  1. 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.

  2. A coupled hydrological-hydraulic flood inundation model calibrated using post-event measurements and integrated uncertainty analysis in a poorly gauged Mediterranean basin

    Science.gov (United States)

    Hdeib, Rouya; Abdallah, Chadi; Moussa, Roger; Colin, Francois

    2017-04-01

    Developing flood inundation maps of defined exceedance probabilities is required to provide information on the flood hazard and the associated risk. A methodology has been developed to model flood inundation in poorly gauged basins, where reliable information on the hydrological characteristics of floods are uncertain and partially captured by the traditional rain-gauge networks. Flood inundation is performed through coupling a hydrological rainfall-runoff (RR) model (HEC-HMS) with a hydraulic model (HEC-RAS). The RR model is calibrated against the January 2013 flood event in the Awali River basin, Lebanon (300 km2), whose flood peak discharge was estimated by post-event measurements. The resulting flows of the RR model are defined as boundary conditions of the hydraulic model, which is run to generate the corresponding water surface profiles and calibrated against 20 post-event surveyed cross sections after the January-2013 flood event. An uncertainty analysis is performed to assess the results of the models. Consequently, the coupled flood inundation model is simulated with design storms and flood inundation maps are generated of defined exceedance probabilities. The peak discharges estimated by the simulated RR model were in close agreement with the results from different empirical and statistical methods. This methodology can be extended to other poorly gauged basins facing common stage-gauge failure or characterized by floods with a stage exceeding the gauge measurement level, or higher than that defined by the rating curve.

  3. 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.

  4. 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…

  5. Off gas condenser performance modelling

    International Nuclear Information System (INIS)

    Cains, P.W.; Hills, K.M.; Waring, S.; Pratchett, A.G.

    1989-12-01

    A suite of three programmes has been developed to model the ruthenium decontamination performance of a vitrification plant off-gas condenser. The stages of the model are: condensation of water vapour, NO x absorption in the condensate, RuO 4 absorption in the condensate. Juxtaposition of these stages gives a package that may be run on an IBM-compatible desktop PC. Experimental work indicates that the criterion [HNO 2 ] > 10 [RuO 4 ] used to determine RuO 4 destruction in solution is probably realistic under condenser conditions. Vapour pressures of RuO 4 over aqueous solutions at 70 o -90 o C are slightly lower than the values given by extrapolating the ln K p vs. T -1 relation derived from lower temperature data. (author)

  6. Data harmonization and model performance

    Science.gov (United States)

    The Joint Committee on Urban Storm Drainage of the International Association for Hydraulic Research (IAHR) and International Association on Water Pollution Research and Control (IAWPRC) was formed in 1982. The current committee members are (no more than two from a country): B. C. Yen, Chairman (USA); P. Harremoes, Vice Chairman (Denmark); R. K. Price, Secretary (UK); P. J. Colyer (UK), M. Desbordes (France), W. C. Huber (USA), K. Krauth (FRG), A. Sjoberg (Sweden), and T. Sueishi (Japan).The IAHR/IAWPRC Joint Committee is forming a Task Group on Data Harmonization and Model Performance. One objective is to promote international urban drainage data harmonization for easy data and information exchange. Another objective is to publicize available models and data internationally. Comments and suggestions concerning the formation and charge of the Task Group are welcome and should be sent to: B. C. Yen, Dept. of Civil Engineering, Univ. of Illinois, 208 N. Romine St., Urbana, IL 61801.

  7. 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.

  8. One-trial conditioned taste aversion in Lymnaea: good and poor performers in long-term memory acquisition.

    Science.gov (United States)

    Sugai, Rio; Azami, Sachiyo; Shiga, Hatsuki; Watanabe, Takayuki; Sadamoto, Hisayo; Kobayashi, Suguru; Hatakeyama, Dai; Fujito, Yutaka; Lukowiak, Ken; Ito, Etsuro

    2007-04-01

    In the majority of studies designed to elucidate the causal mechanisms of memory formation, certain members of the experimental cohort, even though subjected to exactly the same conditioning procedures, remember significantly better than others, whereas others show little or no long-term memory (LTM) formation. To begin to address the question of why this phenomenon occurs and thereby help clarify the causal mechanism of LTM formation, we used a conditioned taste aversion (CTA) procedure on individuals of the pond snail Lymnaea stagnalis and analyzed their subsequent behavior. Using sucrose as an appetitive stimulus and KCl as an aversive stimulus, we obtained a constant ratio of ;poor' to ;good' performers for CTA-LTM. We found that approximately 40% of trained snails possessed LTM following a one-trial conditioning procedure. When we examined the time-window necessary for the memory consolidation, we found that if we cooled snails to 4 degrees C for 30 min within 10 min after the one-trial conditioning, LTM was blocked. However, with delayed cooling (i.e. longer than 10 min), LTM was present. We could further interfere with LTM formation by inducing inhibitory learning (i.e. backward conditioning) after the one-trial conditioning. Finally, we examined whether we could motivate snails to acquire LTM by depriving them of food for 5 days before the one-trial conditioning. Food-deprived snails, however, failed to exhibit LTM following the one-trial conditioning. These results will help us begin to clarify why some individuals are better at learning and forming memory for specific tasks at the neuronal level.

  9. 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

  10. 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

  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. 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

  13. 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)

  14. Why Rural Community Day Secondary Schools Students' Performance in Physical Science Examinations Is Poor in Lilongwe Rural West Education District in Malawi

    Science.gov (United States)

    Mlangeni, Angstone Noel J. Thembachako; Chiotha, Sosten Staphael

    2015-01-01

    A study was conducted to investigate factors that affect students' poor performance in physical science examinations at Malawi School Certificate of Education and Junior Certificate of Education levels in Community day secondary schools (CDSS) in Lilongwe Rural West Education District in Malawi. Students' performance was collected from schools'…

  15. Does Taking One Step Back Get You Two Steps Forward? Grade Retention and School Performance in Poor Areas in Rural China

    Science.gov (United States)

    Chen, Xinxin; Liu, Chengfang; Zhang, Linxiu; Shi, Yaojiang; Rozelle, Scott

    2010-01-01

    Despite the rise in grade retention in poor areas in rural China recently, little work has been done to understand the impact of grade retention on the educational performance of students in these areas in rural China. This paper seeks to redress this shortcoming and examines the effect of grade retention on educational performance on 1649…

  16. 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.

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

    Science.gov (United States)

    Pajić, Nataša Z Bubić; Todosijević, Marija N; Vuleta, Gordana M; Cekić, Nebojša D; Dobričić, Vladimir D; Vučen, Sonja R; Čalija, Bojan R; Lukić, Milica Ž; Ilić, Tanja M; Savić, Snežana D

    2017-12-20

    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.

  18. REMO poor man's reanalysis

    Science.gov (United States)

    Ries, H.; Moseley, C.; Haensler, A.

    2012-04-01

    Reanalyses depict the state of the atmosphere as a best fit in space and time of many atmospheric observations in a physically consistent way. By essentially solving the data assimilation problem in a very accurate manner, reanalysis results can be used as reference for model evaluation procedures and as forcing data sets for different model applications. However, the spatial resolution of the most common and accepted reanalysis data sets (e.g. JRA25, ERA-Interim) ranges from approximately 124 km to 80 km. This resolution is too coarse to simulate certain small scale processes often associated with extreme events. In addition, many models need higher resolved forcing data ( e.g. land-surface models, tools for identifying and assessing hydrological extremes). Therefore we downscaled the ERA-Interim reanalysis over the EURO-CORDEX-Domain for the time period 1989 to 2008 to a horizontal resolution of approximately 12 km. The downscaling is performed by nudging REMO-simulations to lower and lateral boundary conditions of the reanalysis, and by re-initializing the model every 24 hours ("REMO in forecast mode"). In this study the three following questions will be addressed: 1.) Does the REMO poor man's reanalysis meet the needs (accuracy, extreme value distribution) in validation and forcing? 2.) What lessons can be learned about the model used for downscaling? As REMO is used as a pure downscaling procedure, any systematic deviations from ERA-Interim result from poor process modelling but not from predictability limitations. 3.) How much small scale information generated by the downscaling model is lost with frequent initializations? A comparison to a simulation that is performed in climate mode will be presented.

  19. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Carter, J.N. [Department of Earth Science and Engineering, Imperial College, London (United Kingdom)]. E-mail: j.n.carter@ic.ac.uk; Ballester, P.J. [Department of Earth Science and Engineering, Imperial College, London (United Kingdom); Tavassoli, Z. [Department of Earth Science and Engineering, Imperial College, London (United Kingdom); King, P.R. [Department of Earth Science and Engineering, Imperial College, London (United Kingdom)

    2006-10-15

    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.

  1. 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

  2. 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.

  3. Homeostasis model assessment of insulin resistance in relation to the poor functional outcomes in nondiabetic patients with ischemic stroke

    Science.gov (United States)

    Li, Siou; Yin, Changhao; Zhao, Weina; Zhu, Haifu; Xu, Dan; Xu, Qing; Jiao, Yang; Wang, Xue; Qiao, Hong

    2018-01-01

    Whether insulin resistance (IR) predicts worse functional outcome in ischemic stroke is still a matter of debate. The aim of the present study is to determine the association between IR and risk of poor outcome in 173 Chinese nondiabetic patients with acute ischemic stroke. This is a prospective, population-based cohort study. Insulin sensitivity, expressed by the homeostasis model assessment (HOMA) of insulin sensitivity (HOMA index = (fasting insulin × fasting glucose)/22.5). IR was defined by HOMA-IR index in the top quartile (Q4). Functional impairment was evaluated at discharge using the modified Rankin scale (mRS). The median (interquartile range) HOMA-IR was 2.14 (1.17–2.83), and Q4 was at least 2.83. There was a significantly positive correlation between HOMA-IR and National Institutes of Health Stroke Scale (r = 0.408; PIR group were associated with a higher risk of poor functional outcome (odds ratio (OR) = 3.23; 95% confidence interval (CI) = 1.75–5.08; P=0.001). In multivariate models comparing the third and fourth quartiles against the first quartile of the HOMA-IR, levels of HOMA-IR were associated with poor outcome, and the adjusted risk of poor outcome increased by 207% (OR = 3.05 (95% CI 1.70–4.89), P=0.006) and 429% (5.29 (3.05–9.80), PHOMA-IR to clinical examination variables (P=0.02). High HOMA-IR index is associated with a poor functional outcome in nondiabetic patients with acute ischemic stroke. PMID:29588341

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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

    . 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....

  11. 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.

  12. 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].

  13. 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 fee-for-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.

  14. 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.

  15. 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...

  16. 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

  17. 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…

  18. 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

  19. Strategy Choice in Solving Arithmetic Word Problems: Are There Differences between Students with Learning Disabilities, G-V Poor Performance, and Typical Achievement Students?

    Science.gov (United States)

    Gonzalez, Juan E. Jimenez; Espinel, Ana Isabel Garcia

    2002-01-01

    A study was designed to test whether there are differences between Spanish children (ages 7-9) with arithmetic learning disabilities (n=60), garden-variety (G-V) poor performance (n=44), and typical children (n=44) in strategy choice when solving arithmetic word problems. No significant differences were found between children with dyscalculia and…

  20. 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

  1. 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.

  2. Performance Modelling of Steam Turbine Performance using Fuzzy ...

    African Journals Online (AJOL)

    Performance Modelling of Steam Turbine Performance using Fuzzy Logic ... AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING AJOL · RESOURCES. Journal of Applied Sciences and Environmental Management ... A Fuzzy Inference System for predicting the performance of steam turbine

  3. 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...

  4. 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

  5. Photovoltaic array performance simulation models

    Energy Technology Data Exchange (ETDEWEB)

    Menicucci, D. F.

    1986-09-15

    The experience of the solar industry confirms that, despite recent cost reductions, the profitability of photovoltaic (PV) systems is often marginal and the configuration and sizing of a system is a critical problem for the design engineer. Construction and evaluation of experimental systems are expensive and seldom justifiable. A mathematical model or computer-simulation program is a desirable alternative, provided reliable results can be obtained. Sandia National Laboratories, Albuquerque (SNLA), has been studying PV-system modeling techniques in an effort to develop an effective tool to be used by engineers and architects in the design of cost-effective PV systems. This paper reviews two of the sources of error found in previous PV modeling programs, presents the remedies developed to correct these errors, and describes a new program that incorporates these improvements.

  6. Cognitive performance after mild traumatic brain injury: the impact of poor effort on test results and its relation to distress, personality and litigation.

    Science.gov (United States)

    Stulemeijer, Maja; Andriessen, Teuntje M J C; Brauer, Jolanda M P; Vos, Pieter E; Van Der Werf, Sieberen

    2007-03-01

    To compare consecutive Mild Traumatic Brain Injury (MTBI) patients with and without adequate effort on cognitive performance, litigation status, fatigue, distress and personality. (Neuro)psychological assessment was done 6 months post-injury in 110 patients from a cohort of 618 consecutive MTBI patients aged 18-60, who attended the emergency department of our level I trauma centre. Effort was tested with the Amsterdam Short Term Memory test. Thirty patients (27%) failed the effort test. Poor effort was associated with significantly poorer scores on seven out of eleven measures, covering all tested domains. Poor effort was associated with lower educational level and changes in work status, but not litigation. Furthermore, poor effort was related to high levels of distress, Type-D personality and fatigue. Even in a sample of non-referred MTBI patients, poor effort was common and was strongly associated with inferior test performance. These findings imply that effort testing should be part of all cognitive assessments, also outside mediolegal settings. Behavioural factors like distress and personality should be considered as potential threats to the validity of neuropsychological testing after MTBI.

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

    Science.gov (United States)

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

    2012-04-01

    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. 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. 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. 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. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  8. 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.

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

    Science.gov (United States)

    Syhakhang, Lamphone; Soukaloun, Douangdao; Tomson, Göran; Petzold, Max; Rehnberg, Clas; Wahlström, Rolf

    2011-01-06

    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. 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). 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). The lower expenditure for insured patients can help reduce the number of households experiencing catastrophic health

  10. 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

  11. Electrification in rural Bangladesh. A comprehensive analysis on Grameen Shakti's energy for the poor-business model

    Energy Technology Data Exchange (ETDEWEB)

    Weimar, Niclas D.H.

    2010-07-01

    People in industrialized countries enjoy nowadays the luxurious advantages of energy. Electricity has converted the former preindustrial economies and societies into highly industrialized, mechanized and automated ones. On the contrary, many rural areas in developing countries are suffering from the heavy lack of access to energy, such as Bangladesh. Grameen Shakti, a subsidiary of the world famous Grameen family set up by Nobel Laureate Muhammad Yunus, has created a market for renewable energy technologies in Bangladesh, though not in the industrial and commercial areas but in the very poor and energy-starved rural areas of the country. By employing a special market-based business model, Grameen Shakti provides rural households with access to renewable energy technologies and thus with electricity. The objective of this study is the analysis and depiction of the functionality of this business model, its structural aspects, implications as well as replication potential. (orig.)

  12. Maintenance Personnel Performance Simulation (MAPPS) model

    International Nuclear Information System (INIS)

    Siegel, A.I.; Bartter, W.D.; Wolf, J.J.; Knee, H.E.; Haas, P.M.

    1984-01-01

    A stochastic computer model for simulating the actions and behavior of nuclear power plant maintenance personnel is described. The model considers personnel, environmental, and motivational variables to yield predictions of maintenance performance quality and time to perform. The mode has been fully developed and sensitivity tested. Additional evaluation of the model is now taking place

  13. 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).

  14. 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.

  15. Iron-Coupled Anaerobic Oxidation of Methane Performed by a Mixed Bacterial-Archaeal Community Based on Poorly Reactive Minerals.

    Science.gov (United States)

    Bar-Or, Itay; Elvert, Marcus; Eckert, Werner; Kushmaro, Ariel; Vigderovich, Hanni; Zhu, Qingzeng; Ben-Dov, Eitan; Sivan, Orit

    2017-11-07

    Anaerobic oxidation of methane (AOM) was shown to reduce methane emissions by over 50% in freshwater systems, its main natural contributor to the atmosphere. In these environments iron oxides can become main agents for AOM, but the underlying mechanism for this process has remained enigmatic. By conducting anoxic slurry incubations with lake sediments amended with 13 C-labeled methane and naturally abundant iron oxides the process was evidenced by significant 13 C-enrichment of the dissolved inorganic carbon pool and most pronounced when poorly reactive iron minerals such as magnetite and hematite were applied. Methane incorporation into biomass was apparent by strong uptake of 13 C into fatty acids indicative of methanotrophic bacteria, associated with increasing copy numbers of the functional methane monooxygenase pmoA gene. Archaea were not directly involved in full methane oxidation, but their crucial participation, likely being mediators in electron transfer, was indicated by specific inhibition of their activity that fully stopped iron-coupled AOM. By contrast, inhibition of sulfur cycling increased 13 C-methane turnover, pointing to sulfur species involvement in a competing process. Our findings suggest that the mechanism of iron-coupled AOM is accomplished by a complex microbe-mineral reaction network, being likely representative of many similar but hidden interactions sustaining life under highly reducing low energy conditions.

  16. 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.

  17. Hypogammaglobulinemia and Poor Performance Status are Predisposing Factors for Vancomycin-Resistant Enterococcus Colonization in Patients with Hematological Malignancies

    Directory of Open Access Journals (Sweden)

    Elif Gülsüm Ümit

    2017-03-01

    Full Text Available Objective: Vancomycin-resistant enterococci (VRE are common pathogens of hospital-acquired infection. Long hospitalization periods, use of broadspectrum antibiotics, and immunosuppression are major risks for VRE colonization. We aimed to evaluate patients’ characteristics and factors that may contribute to VRE colonization. Materials and Methods: Data of 66 patients with colonization and 112 patients without colonization who were hospitalized in the hematology clinic were collected. Hematological malignancies, preexisting gastrointestinal complaints, the presence of hypogammaglobulinemia at the time of diagnosis, complications like neutropenic enterocolitis (NEC, and Eastern Cooperative Oncology Group (ECOG and Karnofsky performance statuses were recorded. Results: Ages of the patients ranged between 19 and 95 years (mean: 55.99. Karnofsky and ECOG scores were statistically related to VRE colonization (p7 days may also be accepted as a risk factor, independent of diagnosis or antibiotic use. Performance status is also an important factor for colonization, which may be related to poorer hygiene and increased external help.

  18. 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.

  19. 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,...

  20. 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

  1. 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.

  2. Poor correlation between handgrip strength and isokinetic performance of knee flexor and extensor muscles in community-dwelling elderly women.

    Science.gov (United States)

    Felicio, Diogo Carvalho; Pereira, Daniele Sirineu; Assumpção, Alexandra Miranda; de Jesus-Moraleida, Fabianna Resende; de Queiroz, Barbara Zille; da Silva, Juscelio Pereira; de Brito Rosa, Naysa Maciel; Dias, João Marcos Domingues; Pereira, Leani Souza Máximo

    2014-01-01

    To investigate the correlation between handgrip strength and performance of knee flexor and extensor muscles determined using an isokinetic dynamometer in community-dwelling elderly women. This was a cross-sectional study. Sample selection for the study was made by convenience, and 221 (71.07 ± 4.93 years) community-dwelling elderly women were included. Knee flexor and extensor muscle performance was measured using an isokinetic dynamometer Biodex System 3 Pro. The isokinetic variables chosen for analysis were peak torque, peak torque/bodyweight, total work/bodyweight, total work, average power, and agonist/antagonist ratio at the angular velocities of 60°/s and 180°/s. Assessment of handgrip strength was carried out using the Jamar dynamometer. Spearman's correlation coefficient was calculated to identify intervariable correlations. Only knee flexor peak torque (60°/s) and average power (60°/s), and knee extensor peak torque (180°/s) and total work (180°/s) were significantly (P women. © 2013 Japan Geriatrics Society.

  3. Stunting, selenium deficiency and anemia are associated with poor cognitive performance in preschool children from rural Ethiopia.

    Science.gov (United States)

    Gashu, Dawd; Stoecker, Barbara J; Bougma, Karim; Adish, Abdulaziz; Haki, Gulelat D; Marquis, Grace S

    2016-04-12

    Anthropometric characteristics and iron status affect cognitive performance in children. In addition, selenium can influence cognitive outcomes; protection of the brain from oxidative stress and its role in thyroid hormone metabolism are putative mechanisms. To investigate their association with cognitive performance, anthropometric indicators, iron biomarkers, and serum selenium of children (n = 541) of 54-60mo of age from rural Ethiopia were assessed. Cognitive assessment was conducted with the administration of two reasoning subtests of the Wechsler Preschool and Primary Scale of Intelligence and the school readiness test. Stunting was found in 41.4 % of children, 28.7 % were underweight, and 6.3 % were wasted. The mean score of stunted children was lower than that of non-stunted children on non-verbal reasoning (7.0 ± 3.2vs7.9 ± 3.1; p = 0.01) and the school readiness tests (4.3 ± 2.2 vs 3.3 ± 2.1; p 0.05). Selenium deficient children had lower scores on all cognitive tests than normal children (p malnutrition and micronutrient deficiency and address cognitive development in children.

  4. 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

  5. Work domain constraints for modelling surgical performance.

    Science.gov (United States)

    Morineau, Thierry; Riffaud, Laurent; Morandi, Xavier; Villain, Jonathan; Jannin, Pierre

    2015-10-01

    Three main approaches can be identified for modelling surgical performance: a competency-based approach, a task-based approach, both largely explored in the literature, and a less known work domain-based approach. The work domain-based approach first describes the work domain properties that constrain the agent's actions and shape the performance. This paper presents a work domain-based approach for modelling performance during cervical spine surgery, based on the idea that anatomical structures delineate the surgical performance. This model was evaluated through an analysis of junior and senior surgeons' actions. Twenty-four cervical spine surgeries performed by two junior and two senior surgeons were recorded in real time by an expert surgeon. According to a work domain-based model describing an optimal progression through anatomical structures, the degree of adjustment of each surgical procedure to a statistical polynomial function was assessed. Each surgical procedure showed a significant suitability with the model and regression coefficient values around 0.9. However, the surgeries performed by senior surgeons fitted this model significantly better than those performed by junior surgeons. Analysis of the relative frequencies of actions on anatomical structures showed that some specific anatomical structures discriminate senior from junior performances. The work domain-based modelling approach can provide an overall statistical indicator of surgical performance, but in particular, it can highlight specific points of interest among anatomical structures that the surgeons dwelled on according to their level of expertise.

  6. 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.

  7. 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.

  8. 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

    2014-01-01

    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. PMID:24978879

  9. Excessive Video Game Use, Sleep Deprivation, and Poor Work Performance Among U.S. Marines Treated in a Military Mental Health Clinic: A Case Series.

    Science.gov (United States)

    Eickhoff, Erin; Yung, Kathryn; Davis, Diane L; Bishop, Frank; Klam, Warren P; Doan, Andrew P

    2015-07-01

    Excessive use of video games may be associated with sleep deprivation, resulting in poor job performance and atypical mood disorders. Three active duty service members in the U.S. Marine Corps were offered mental health evaluation for sleep disturbance and symptoms of blunted affect, low mood, poor concentration, inability to focus, irritability, and drowsiness. All three patients reported insomnia as their primary complaint. When asked about online video games and sleep hygiene practices, all three patients reported playing video games from 30 hours to more than 60 hours per week in addition to maintaining a 40-hour or more workweek. Our patients endorsed sacrificing sleep to maintain their video gaming schedules without insight into the subsequent sleep deprivation. During the initial interviews, they exhibited blunted affects and depressed moods, but appeared to be activated with enthusiasm and joy when discussing their video gaming with the clinical provider. Our article illustrates the importance of asking about online video gaming in patients presenting with sleep disturbances, poor work performance, and depressive symptoms. Because excessive video gaming is becoming more prevalent worldwide, military mental health providers should ask about video gaming when patients report problems with sleep. Reprint & Copyright © 2015 Association of Military Surgeons of the U.S.

  10. 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 ...

  11. 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.

  12. Transmutation Fuel Performance Code Thermal Model Verification

    Energy Technology Data Exchange (ETDEWEB)

    Gregory K. Miller; Pavel G. Medvedev

    2007-09-01

    FRAPCON fuel performance code is being modified to be able to model performance of the nuclear fuels of interest to the Global Nuclear Energy Partnership (GNEP). The present report documents the effort for verification of the FRAPCON thermal model. It was found that, with minor modifications, FRAPCON thermal model temperature calculation agrees with that of the commercial software ABAQUS (Version 6.4-4). This report outlines the methodology of the verification, code input, and calculation results.

  13. Derivation of flood frequency curves in poorly gauged Mediterranean catchments using a simple stochastic hydrological rainfall-runoff model

    Science.gov (United States)

    Aronica, G. T.; Candela, A.

    2007-12-01

    SummaryIn this paper a Monte Carlo procedure for deriving frequency distributions of peak flows using a semi-distributed stochastic rainfall-runoff model is presented. The rainfall-runoff model here used is very simple one, with a limited number of parameters and practically does not require any calibration, resulting in a robust tool for those catchments which are partially or poorly gauged. The procedure is based on three modules: a stochastic rainfall generator module, a hydrologic loss module and a flood routing module. In the rainfall generator module the rainfall storm, i.e. the maximum rainfall depth for a fixed duration, is assumed to follow the two components extreme value (TCEV) distribution whose parameters have been estimated at regional scale for Sicily. The catchment response has been modelled by using the Soil Conservation Service-Curve Number (SCS-CN) method, in a semi-distributed form, for the transformation of total rainfall to effective rainfall and simple form of IUH for the flood routing. Here, SCS-CN method is implemented in probabilistic form with respect to prior-to-storm conditions, allowing to relax the classical iso-frequency assumption between rainfall and peak flow. The procedure is tested on six practical case studies where synthetic FFC (flood frequency curve) were obtained starting from model variables distributions by simulating 5000 flood events combining 5000 values of total rainfall depth for the storm duration and AMC (antecedent moisture conditions) conditions. The application of this procedure showed how Monte Carlo simulation technique can reproduce the observed flood frequency curves with reasonable accuracy over a wide range of return periods using a simple and parsimonious approach, limited data input and without any calibration of the rainfall-runoff model.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Intensive precipitation observation greatly improves hydrological modelling of the poorly gauged high mountain Mabengnong catchment in the Tibetan Plateau

    Science.gov (United States)

    Wang, Li; Zhang, Fan; Zhang, Hongbo; Scott, Christopher A.; Zeng, Chen; Shi, Xiaonan

    2018-01-01

    Precipitation is one of the most critical inputs for models used to improve understanding of hydrological processes. In high mountain areas, it is challenging to generate a reliable precipitation data set capturing the spatial and temporal heterogeneity due to the harsh climate, extreme terrain and the lack of observations. This study conducts intensive observation of precipitation in the Mabengnong catchment in the southeast of the Tibetan Plateau during July to August 2013. Because precipitation is greatly influenced by altitude, the observed data are used to characterize the precipitation gradient (PG) and hourly distribution (HD), showing that the average PG is 0.10, 0.28 and 0.26 mm/d/100 m and the average duration is around 0.1, 0.8 and 5.2 h for trace, light and moderate rain, respectively. A distributed biosphere hydrological model based on water and energy budgets with improved physical process for snow (WEB-DHM-S) is applied to simulate the hydrological processes with gridded precipitation data derived from a lower altitude meteorological station and the PG and HD characterized for the study area. The observed runoff, MODIS/Terra snow cover area (SCA) data, and MODIS/Terra land surface temperature (LST) data are used for model calibration and validation. Runoff, SCA and LST simulations all show reasonable results. Sensitivity analyses illustrate that runoff is largely underestimated without considering PG, indicating that short-term intensive precipitation observation has the potential to greatly improve hydrological modelling of poorly gauged high mountain catchments.

  19. 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.

  20. Diagnostic Performance of CT for Diagnosis of Fat-Poor Angiomyolipoma in Patients With Renal Masses: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Woo, Sungmin; Suh, Chong Hyun; Cho, Jeong Yeon; Kim, Sang Youn; Kim, Seung Hyup

    2017-11-01

    The purpose of this article is to systematically review and perform a meta-analysis of the diagnostic performance of CT for diagnosis of fat-poor angiomyolipoma (AML) in patients with renal masses. MEDLINE and EMBASE were systematically searched up to February 2, 2017. We included diagnostic accuracy studies that used CT for diagnosis of fat-poor AML in patients with renal masses, using pathologic examination as the reference standard. Two independent reviewers assessed the methodologic quality using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Sensitivity and specificity of included studies were calculated and were pooled and plotted in a hierarchic summary ROC plot. Sensitivity analyses using several clinically relevant covariates were performed to explore heterogeneity. Fifteen studies (2258 patients) were included. Pooled sensitivity and specificity were 0.67 (95% CI, 0.48-0.81) and 0.97 (95% CI, 0.89-0.99), respectively. Substantial and considerable heterogeneity was present with regard to sensitivity and specificity (I 2 = 91.21% and 78.53%, respectively). At sensitivity analyses, the specificity estimates were comparable and consistently high across all subgroups (0.93-1.00), but sensitivity estimates showed significant variation (0.14-0.82). Studies using pixel distribution analysis (n = 3) showed substantially lower sensitivity estimates (0.14; 95% CI, 0.04-0.40) compared with the remaining 12 studies (0.81; 95% CI, 0.76-0.85). CT shows moderate sensitivity and excellent specificity for diagnosis of fat-poor AML in patients with renal masses. When methods other than pixel distribution analysis are used, better sensitivity can be achieved.

  1. 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.

  2. Reduced ovulation rate, failure to be mated and fertilization failure/embryo loss are the underlying causes of poor reproductive performance in juvenile ewes.

    Science.gov (United States)

    Edwards, Sara J; Smaill, Bronwyn; O'Connell, Anne R; Johnstone, Peter D; Stevens, David R; Quirke, Laurel D; Farquhar, Philip A; Juengel, Jennifer L

    2016-04-01

    A ewe that is mated as a juvenile (producing a lamb at 1 year of age) will produce an average of only 0.6 lambs to weaning, compared to an average of 1.2 lambs in adult ewes. Understanding the underlying causes of this low reproductive efficiency and designing methods to improve or mitigate these effects could potentially increase adoption of mating juvenile ewes. In Experiment 1, 2 Cohorts of ewes, born a year apart, were mated in order to lamb at 1 and 2 years of age and the performance of the ewes at each age was compared. Onset of puberty, mating by the fertile ram, ovulation rate, early pregnancy (day 30-35) litter size, number of lambs born and number of lambs weaned were measured. In juvenile ewes, by day 35 of pregnancy, 43% of ova had failed to become a viable embryo and this early loss was the largest contributor to the poor reproductive performance observed. Compared with young adult ewes, ovulation rate was lower (pewes with a greater ovulation rate (pewes, failure to mate with the ram, lower ovulation rate and increased fertilisation failure/embryo loss underlie their poor reproductive performance. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Performance of different radiotherapy workload models

    International Nuclear Information System (INIS)

    Barbera, Lisa; Jackson, Lynda D.; Schulze, Karleen; Groome, Patti A.; Foroudi, Farshad; Delaney, Geoff P.; Mackillop, William J.

    2003-01-01

    Purpose: The purpose of this study was to evaluate the performance of different radiotherapy workload models using a prospectively collected dataset of patient and treatment information from a single center. Methods and Materials: Information about all individual radiotherapy treatments was collected for 2 weeks from the three linear accelerators (linacs) in our department. This information included diagnosis code, treatment site, treatment unit, treatment time, fields per fraction, technique, beam type, blocks, wedges, junctions, port films, and Eastern Cooperative Oncology Group (ECOG) performance status. We evaluated the accuracy and precision of the original and revised basic treatment equivalent (BTE) model, the simple and complex Addenbrooke models, the equivalent simple treatment visit (ESTV) model, fields per hour, and two local standards of workload measurement. Results: Data were collected for 2 weeks in June 2001. During this time, 151 patients were treated with 857 fractions. The revised BTE model performed better than the other models with a mean vertical bar observed - predicted vertical bar of 2.62 (2.44-2.80). It estimated 88.0% of treatment times within 5 min, which is similar to the previously reported accuracy of the model. Conclusion: The revised BTE model had similar accuracy and precision for data collected in our center as it did for the original dataset and performed the best of the models assessed. This model would have uses for patient scheduling, and describing workloads and case complexity

  4. 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...

  5. Poor performances of EuroSCORE and CARE score for prediction of perioperative mortality in octogenarians undergoing aortic valve replacement for aortic stenosis.

    Science.gov (United States)

    Chhor, Vibol; Merceron, Sybille; Ricome, Sylvie; Baron, Gabriel; Daoud, Omar; Dilly, Marie-Pierre; Aubier, Benjamin; Provenchere, Sophie; Philip, Ivan

    2010-08-01

    Although results of cardiac surgery are improving, octogenarians have a higher procedure-related mortality and more complications with increased length of stay in ICU. Consequently, careful evaluation of perioperative risk seems necessary. The aims of our study were to assess and compare the performances of EuroSCORE and CARE score in the prediction of perioperative mortality among octogenarians undergoing aortic valve replacement for aortic stenosis and to compare these predictive performances with those obtained in younger patients. This retrospective study included all consecutive patients undergoing cardiac surgery in our institution between November 2005 and December 2007. For each patient, risk assessment for mortality was performed using logistic EuroSCORE, additive EuroSCORE and CARE score. The main outcome measure was early postoperative mortality. Predictive performances of these scores were assessed by calibration and discrimination using goodness-of-fit test and area under the receiver operating characteristic curve, respectively. During this 2-year period, we studied 2117 patients, among whom 134/211 octogenarians and 335/1906 nonoctogenarians underwent an aortic valve replacement for aortic stenosis. When considering patients with aortic stenosis, discrimination was poor in octogenarians and the difference from nonoctogenarians was significant for each score (0.58, 0.59 and 0.56 vs. 0.82, 0.81 and 0.77 for additive EuroSCORE, logistic EuroSCORE and CARE score in octogenarians and nonoctogenarians, respectively, P performances of these scores are poor in octogenarians undergoing cardiac surgery, especially aortic valve replacement. Risk assessment and therapeutic decisions in octogenarians should not be made with these scoring systems alone.

  6. 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.

  7. Cost and Performance Model for Photovoltaic Systems

    Science.gov (United States)

    Borden, C. S.; Smith, J. H.; Davisson, M. C.; Reiter, L. J.

    1986-01-01

    Lifetime cost and performance (LCP) model assists in assessment of design options for photovoltaic systems. LCP is simulation of performance, cost, and revenue streams associated with photovoltaic power systems connected to electric-utility grid. LCP provides user with substantial flexibility in specifying technical and economic environment of application.

  8. 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.

  9. Performance engineering in the community atmosphere model

    International Nuclear Information System (INIS)

    Worley, P; Mirin, A; Drake, J; Sawyer, W

    2006-01-01

    The Community Atmosphere Model (CAM) is the atmospheric component of the Community Climate System Model (CCSM) and is the primary consumer of computer resources in typical CCSM simulations. Performance engineering has been an important aspect of CAM development throughout its existence. This paper briefly summarizes these efforts and their impacts over the past five years

  10. 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

  11. Performability assessment by model checking of Markov reward models

    NARCIS (Netherlands)

    Baier, Christel; Cloth, L.; Haverkort, Boudewijn R.H.M.; Hermanns, H.; Katoen, Joost P.

    2010-01-01

    This paper describes efficient procedures for model checking Markov reward models, that allow us to evaluate, among others, the performability of computer-communication systems. We present the logic CSRL (Continuous Stochastic Reward Logic) to specify performability measures. It provides flexibility

  12. 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

  13. Analytical performance modeling for computer systems

    CERN Document Server

    Tay, Y C

    2013-01-01

    This book is an introduction to analytical performance modeling for computer systems, i.e., writing equations to describe their performance behavior. It is accessible to readers who have taken college-level courses in calculus and probability, networking and operating systems. This is not a training manual for becoming an expert performance analyst. Rather, the objective is to help the reader construct simple models for analyzing and understanding the systems that they are interested in.Describing a complicated system abstractly with mathematical equations requires a careful choice of assumpti

  14. 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.

  15. 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

  16. Shock circle model for ejector performance evaluation

    International Nuclear Information System (INIS)

    Zhu, Yinhai; Cai, Wenjian; Wen, Changyun; Li, Yanzhong

    2007-01-01

    In this paper, a novel shock circle model for the prediction of ejector performance at the critical mode operation is proposed. By introducing the 'shock circle' at the entrance of the constant area chamber, a 2D exponential expression for velocity distribution is adopted to approximate the viscosity flow near the ejector inner wall. The advantage of the 'shock circle' analysis is that the calculation of ejector performance is independent of the flows in the constant area chamber and diffuser. Consequently, the calculation is even simpler than many 1D modeling methods and can predict the performance of critical mode operation ejectors much more accurately. The effectiveness of the method is validated by two experimental results reported earlier. The proposed modeling method using two coefficients is shown to produce entrainment ratio, efficiency and coefficient of performance (COP) accurately and much closer to experimental results than those of 1D analysis methods

  17. 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)

  18. 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.

  19. 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.

  20. 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

  1. Identifying subgroups among poor prognosis patients with nonseminomatous germ cell cancer by tree modelling: a validation study.

    NARCIS (Netherlands)

    M.R. van Dijk (Merel); E.W. Steyerberg (Ewout); S.P. Stenning; J.D.F. Habbema (Dik)

    2004-01-01

    textabstractBACKGROUND: In order to target intensive treatment strategies for poor prognosis patients with non-seminomatous germ cell cancer, those with the poorest prognosis should be identified. These patients might profit most from more intensive treatment strategies. For

  2. 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

  3. 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.

  4. 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

  5. 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

  6. Cetuximab plus FOLFOX for Patients with Metastatic Colorectal Cancer with Poor Performance Status and/or Severe Tumor-Related Complications

    Science.gov (United States)

    Shitara, Kohei; Yokota, Tomoya; Takahari, Daisuke; Shibata, Takashi; Sato, Yozo; Tajika, Masahiro; Ura, Takashi; Muro, Kei

    2010-01-01

    Introduction Cetuximab-based chemotherapy showed a statistically significantly higher response rate compared with chemotherapy such as FOLFOX. Therefore, FOLFOX plus cetuximab is suspected to be the best regimen to alleviate tumor-related symptoms with a high response rate. Case Report Here we present the results of 8 consecutive patients with metastatic colorectal cancer with poor performance status and/or severe complications who were treated with first-line FOLFOX with cetuximab. Six of 8 patients achieved an apparent clinical benefit, including radiological response and symptoms improvement. Two patients with BRAF mutation could achieve neither clinical benefit nor radiological response. Conclusion Although an optimal line of therapy with cetuximab is unclear yet with bevacizumab in mind, we propose that patients who need a tumor response to alleviate their symptoms due to advanced disease might be candidates for first-line cetuximab-based therapy as shown in our cases. Additionally, patients with BRAF mutant tumors might be important candidates for novel targeted therapy in the future to improve their poor prognosis. PMID:21347194

  7. Cetuximab plus FOLFOX for Patients with Metastatic Colorectal Cancer with Poor Performance Status and/or Severe Tumor-Related Complications

    Directory of Open Access Journals (Sweden)

    Kohei Shitara

    2010-07-01

    Full Text Available Introduction: Cetuximab-based chemotherapy showed a statistically significantly higher response rate compared with chemotherapy such as FOLFOX. Therefore, FOLFOX plus cetuximab is suspected to be the best regimen to alleviate tumor-related symptoms with a high response rate. Case Report: Here we present the results of 8 consecutive patients with metastatic colorectal cancer with poor performance status and/or severe complications who were treated with first-line FOLFOX with cetuximab. Six of 8 patients achieved an apparent clinical benefit, including radiological response and symptoms improvement. Two patients with BRAF mutation could achieve neither clinical benefit nor radiological response. Conclusion: Although an optimal line of therapy with cetuximab is unclear yet with bevacizumab in mind, we propose that patients who need a tumor response to alleviate their symptoms due to advanced disease might be candidates for first-line cetuximab-based therapy as shown in our cases. Additionally, patients with BRAF mutant tumors might be important candidates for novel targeted therapy in the future to improve their poor prognosis.

  8. 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.

  9. Wave and Wind Model Performance Metrics Tools

    Science.gov (United States)

    Choi, J. K.; Wang, D. W.

    2016-02-01

    Continual improvements and upgrades of Navy ocean wave and wind models are essential to the assurance of battlespace environment predictability of ocean surface wave and surf conditions in support of Naval global operations. Thus, constant verification and validation of model performance is equally essential to assure the progress of model developments and maintain confidence in the predictions. Global and regional scale model evaluations may require large areas and long periods of time. For observational data to compare against, altimeter winds and waves along the tracks from past and current operational satellites as well as moored/drifting buoys can be used for global and regional coverage. Using data and model runs in previous trials such as the planned experiment, the Dynamics of the Adriatic in Real Time (DART), we demonstrated the use of accumulated altimeter wind and wave data over several years to obtain an objective evaluation of the performance the SWAN (Simulating Waves Nearshore) model running in the Adriatic Sea. The assessment provided detailed performance of wind and wave models by using cell-averaged statistical variables maps with spatial statistics including slope, correlation, and scatter index to summarize model performance. Such a methodology is easily generalized to other regions and at global scales. Operational technology currently used by subject matter experts evaluating the Navy Coastal Ocean Model and the Hybrid Coordinate Ocean Model can be expanded to evaluate wave and wind models using tools developed for ArcMAP, a GIS application developed by ESRI. Recent inclusion of altimeter and buoy data into a format through the Naval Oceanographic Office's (NAVOCEANO) quality control system and the netCDF standards applicable to all model output makes it possible for the fusion of these data and direct model verification. Also, procedures were developed for the accumulation of match-ups of modelled and observed parameters to form a data base

  10. 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.

  11. Measurement-based reliability/performability models

    Science.gov (United States)

    Hsueh, Mei-Chen

    1987-01-01

    Measurement-based models based on real error-data collected on a multiprocessor system are described. Model development from the raw error-data to the estimation of cumulative reward is also described. A workload/reliability model is developed based on low-level error and resource usage data collected on an IBM 3081 system during its normal operation in order to evaluate the resource usage/error/recovery process in a large mainframe system. Thus, both normal and erroneous behavior of the system are modeled. The results provide an understanding of the different types of errors and recovery processes. The measured data show that the holding times in key operational and error states are not simple exponentials and that a semi-Markov process is necessary to model the system behavior. A sensitivity analysis is performed to investigate the significance of using a semi-Markov process, as opposed to a Markov process, to model the measured system.

  12. 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) ...

  13. A Procurement Performance Model for Construction Frameworks

    Directory of Open Access Journals (Sweden)

    Terence Y M Lam

    2015-07-01

    Full Text Available Collaborative construction frameworks have been developed in the United Kingdom (UK to create longer term relationships between clients and suppliers in order to improve project outcomes. Research undertaken into highways maintenance set within a major county council has confirmed that such collaborative procurement methods can improve time, cost and quality of construction projects. Building upon this and examining the same single case, this research aims to develop a performance model through identification of performance drivers in the whole project delivery process including pre and post contract phases. A priori performance model based on operational and sociological constructs was proposed and then checked by a pilot study. Factor analysis and central tendency statistics from the questionnaires as well as content analysis from the interview transcripts were conducted. It was confirmed that long term relationships, financial and non-financial incentives and stronger communication are the sociological behaviour factors driving performance. The interviews also established that key performance indicators (KPIs can be used as an operational measure to improve performance. With the posteriori performance model, client project managers can effectively collaboratively manage contractor performance through procurement measures including use of longer term and KPIs for the contract so that the expected project outcomes can be achieved. The findings also make significant contribution to construction framework procurement theory by identifying the interrelated sociological and operational performance drivers. This study is set predominantly in the field of highways civil engineering. It is suggested that building based projects or other projects that share characteristics are grouped together and used for further research of the phenomena discovered.

  14. Models for Automated Tube Performance Calculations

    International Nuclear Information System (INIS)

    Brunkhorst, C.

    2002-01-01

    High power radio-frequency systems, as typically used in fusion research devices, utilize vacuum tubes. Evaluation of vacuum tube performance involves data taken from tube operating curves. The acquisition of data from such graphical sources is a tedious process. A simple modeling method is presented that will provide values of tube currents for a given set of element voltages. These models may be used as subroutines in iterative solutions of amplifier operating conditions for a specific loading impedance

  15. 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.

  16. 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

  17. 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).

  18. 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)

  19. 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

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Short-course radiotherapy, with elective delay prior to surgery, in patients with unresectable rectal cancer who have poor performance status or significant co-morbidity

    International Nuclear Information System (INIS)

    Hatfield, Paul; Hingorani, Mohan; Radhakrishna, Ganesh; Cooper, Rachel; Melcher, Alan; Crellin, Adrian; Kwok-Williams, Michelle; Sebag-Montefiore, David

    2009-01-01

    Background and purpose: Standard treatment for rectal cancer which threatens the expected plane of resection on MRI imaging is long-course, pre-operative chemoradiotherapy (1.8-2 Gy, 25-28 fractions). Not all patients are suitable for this because of age, poor performance status or co-morbidities. We describe our experience of short-course (5 x 5 Gy) pre-operative radiotherapy with planned, delayed surgery (SCPRT-delay) in this patient group. Materials and methods: Between April 2001 and October 2007, 43 patients were selected for SCPRT-delay. The clinical records were retrospectively evaluated. Results: Median age was 82 (range 58-87). Forty-one patients had radiotherapy of which 26 (61%) were subsequently able to have surgery. Of these, R0, R1 and R2 resections were performed in 22, 2 and 2 patients, respectively. Treatment was well tolerated, although two patients required hospital admission for management of diarrhoea and one developed significant late small bowel toxicity, attributable to radiotherapy. In those undergoing R0 or R1 resection there have been no local recurrences (median follow-up 18 months). Median survival for the whole group was 23 months, although this was 44 months in those undergoing surgery. Conclusions: SCPRT-delay appears to be a useful alternative to long-course pre-operative chemoradiotherapy in this high-risk group of patients.

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. Multilevel Modeling of the Performance Variance

    Directory of Open Access Journals (Sweden)

    Alexandre Teixeira Dias

    2012-12-01

    Full Text Available Focusing on the identification of the role played by Industry on the relations between Corporate Strategic Factors and Performance, the hierarchical multilevel modeling method was adopted when measuring and analyzing the relations between the variables that comprise each level of analysis. The adequacy of the multilevel perspective to the study of the proposed relations was identified and the relative importance analysis point out to the lower relevance of industry as a moderator of the effects of corporate strategic factors on performance, when the latter was measured by means of return on assets, and that industry don‟t moderates the relations between corporate strategic factors and Tobin‟s Q. The main conclusions of the research are that the organizations choices in terms of corporate strategy presents a considerable influence and plays a key role on the determination of performance level, but that industry should be considered when analyzing the performance variation despite its role as a moderator or not of the relations between corporate strategic factors and performance.

  16. 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.

  17. 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)

  18. Combining satellite radar altimetry, SAR surface soil moisture and GRACE total storage changes for hydrological model calibration in a large poorly gauged catchment

    DEFF Research Database (Denmark)

    Milzow, Christian; Krogh, Pernille Engelbredt; Bauer-Gottwein, Peter

    2011-01-01

    The availability of data is a major challenge for hydrological modelling in large parts of the world. Remote sensing data can be exploited to improve models of ungauged or poorly gauged catchments. In this study we combine three datasets for calibration of a rainfall-runoff model of the poorly...... gauged Okavango catchment in Southern Africa: (i) surface soil moisture (SSM) estimates derived from radar measurements onboard the Envisat satellite; (ii) radar altimetry measurements by Envisat providing river stages in the tributaries of the Okavango catchment, down to a minimum river width of about...... one hundred meters; and (iii) temporal changes of the Earth's gravity field recorded by the Gravity Recovery and Climate Experiment (GRACE) caused by total water storage changes in the catchment. The SSM data are shown to be helpful in identifying periods with over-respectively underestimation...

  19. 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.

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

    Directory of Open Access Journals (Sweden)

    Marlene Perignon

    Full Text Available BACKGROUND: Nutrition is one of many factors affecting the cognitive development of children. In Cambodia, 55% of children <5 y were anemic and 40% stunted in 2010. Currently, no data exists on the nutritional status of Cambodian school-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 using Raven's Colored Progressive Matrices (RCPM and block design and picture completion, two standardized tests from the Wechsler Intelligence Scale for Children (WISC-III. RESULTS: The prevalence of anemia, iron, zinc, iodine and vitamin A deficiency were 15.7%; 51.2%, 92.8%, 17.3% and 0.7% respectively. The prevalence of stunting was 40.0%, including 10.9% of severe stunting. Stunted children scored significantly lower than non-stunted children on all tests. In RCPM test, boys with iron-deficiency anemia had lower scores than boys with normal iron status (-1.46, p<0.05. In picture completion test, children with normal iron status tended to score higher than iron-deficient children with anemia (-0.81; p = 0.067 or without anemia (-0.49; p = 0.064. Parasite infection was associated with an increase in risk of scoring below the median value in block design test (OR = 1.62; p<0.05, and with lower scores in other tests, for girls only (both p<0.05. CONCLUSION: Poor cognitive performance of Cambodian school-children was multifactorial and

  1. 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.

  2. Comparison of biexponential and monoexponential model of diffusion-weighted imaging for distinguishing between common renal cell carcinoma and fat poor angiomyolipoma

    International Nuclear Information System (INIS)

    Ding, Yuqin; Zeng, Mengsu; Rao, Shengxiang; Chen, Caizhong; Fu, Caixia

    2016-01-01

    To compare the diagnostic accuracy of intravoxel incoherent motion (IVIM)-derived parameters and apparent diffusion coefficient (ADC) in distinguishing between renal cell carcinoma (RCC) and fat poor angiomyolipoma (AML). Eighty-three patients with pathologically confirmed renal tumors were included in the study. All patients underwent renal 1.5T MRI, including IVIM protocol with 8 b values (0-800 s/mm"2). The ADC, diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) were calculated. One-way ANOVA was used for comparing ADC and IVIM-derived parameters among clear cell RCC (ccRCC), non-ccRCC and fat poor AML. The diagnostic performance of these parameters was evaluated by using receiver operating characteristic (ROC) analysis. The ADC were significantly greater in ccRCCs than that of non-ccRCCs and fat poor AMLs (each p 0.97 × 10"-"3 mm"2/s, D* < 28.03 × 10"-"3 mm"2/s, and f < 13.61% maximized the diagnostic sensitivity for distinguishing non-ccRCCs from fat poor AMLs. The final estimates of AUC (95% confidence interval), sensitivity, specificity, positive predictive value, negative predictive value and accuracy for the entire cohort were 0.875 (0.719-0.962), 100% (23/23), 75% (9/12), 88.5% (23/26), 100% (9/9), and 91.4% (32/35), respectively. The ADC and D showed similar diagnostic accuracy in distinguishing between ccRCCs and fat poor AMLs. The IVIM-derived parameters were better than ADC in discriminating non-ccRCCs from fat poor AMLs

  3. CASTOR detector. Model, objectives and simulated performance

    International Nuclear Information System (INIS)

    Angelis, A. L. S.; Mavromanolakis, G.; Panagiotou, A. D.; Aslanoglou, X.; Nicolis, N.; Lobanov, M.; Erine, S.; Kharlov, Y. V.; Bogolyubsky, M. Y.; Kurepin, A. B.; Chileev, K.; Wlodarczyk, Z.

    2001-01-01

    It is presented a phenomenological model describing the formation and evolution of a Centauro fireball in the baryon-rich region in nucleus-nucleus interactions in the upper atmosphere and at the LHC. The small particle multiplicity and imbalance of electromagnetic and hadronic content characterizing a Centauro event and also the strongly penetrating particles (assumed to be strangelets) frequently accompanying them can be naturally explained. It is described the CASTOR calorimeter, a sub detector of the ALICE experiment dedicated to the search for Centauro in the very forward, baryon-rich region of central Pb+Pb collisions at the LHC. The basic characteristics and simulated performance of the calorimeter are presented

  4. Combining satellite radar altimetry, SAR surface soil moisture and GRACE total storage changes for hydrological model calibration in a large poorly gauged catchment

    Directory of Open Access Journals (Sweden)

    C. Milzow

    2011-06-01

    Full Text Available The availability of data is a major challenge for hydrological modelling in large parts of the world. Remote sensing data can be exploited to improve models of ungauged or poorly gauged catchments. In this study we combine three datasets for calibration of a rainfall-runoff model of the poorly gauged Okavango catchment in Southern Africa: (i surface soil moisture (SSM estimates derived from radar measurements onboard the Envisat satellite; (ii radar altimetry measurements by Envisat providing river stages in the tributaries of the Okavango catchment, down to a minimum river width of about one hundred meters; and (iii temporal changes of the Earth's gravity field recorded by the Gravity Recovery and Climate Experiment (GRACE caused by total water storage changes in the catchment. The SSM data are shown to be helpful in identifying periods with over-respectively underestimation of the precipitation input. The accuracy of the radar altimetry data is validated on gauged subbasins of the catchment and altimetry data of an ungauged subbasin is used for model calibration. The radar altimetry data are important to condition model parameters related to channel morphology such as Manning's roughness. GRACE data are used to validate the model and to condition model parameters related to various storage compartments in the hydrological model (e.g. soil, groundwater, bank storage etc.. As precipitation input the FEWS-Net RFE, TRMM 3B42 and ECMWF ERA-Interim datasets are considered and compared.

  5. Comparison of biexponential and monoexponential model of diffusion-weighted imaging for distinguishing between common renal cell carcinoma and fat poor angiomyolipoma

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yuqin; Zeng, Mengsu; Rao, Shengxiang; Chen, Caizhong [Dept. of Radiology, Zhongshan Hospital, Fudan University, Shanghai Institute of Medical Imaging, Shanghai (China); Fu, Caixia [Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen (China)

    2016-11-15

    To compare the diagnostic accuracy of intravoxel incoherent motion (IVIM)-derived parameters and apparent diffusion coefficient (ADC) in distinguishing between renal cell carcinoma (RCC) and fat poor angiomyolipoma (AML). Eighty-three patients with pathologically confirmed renal tumors were included in the study. All patients underwent renal 1.5T MRI, including IVIM protocol with 8 b values (0-800 s/mm{sup 2}). The ADC, diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) were calculated. One-way ANOVA was used for comparing ADC and IVIM-derived parameters among clear cell RCC (ccRCC), non-ccRCC and fat poor AML. The diagnostic performance of these parameters was evaluated by using receiver operating characteristic (ROC) analysis. The ADC were significantly greater in ccRCCs than that of non-ccRCCs and fat poor AMLs (each p < 0.010, respectively). The D and D* among the three groups were significantly different (all p < 0.050). The f of non-ccRCCs were less than that of ccRCCs and fat poor AMLs (each p < 0.050, respectively). In ROC analysis, ADC and D showed similar area under the ROC curve (AUC) values (AUC = 0.955 and 0.964, respectively, p = 0.589) in distinguishing between ccRCCs and fat poor AMLs. The combination of D > 0.97 × 10{sup -3} mm{sup 2}/s, D* < 28.03 × 10{sup -3} mm{sup 2}/s, and f < 13.61% maximized the diagnostic sensitivity for distinguishing non-ccRCCs from fat poor AMLs. The final estimates of AUC (95% confidence interval), sensitivity, specificity, positive predictive value, negative predictive value and accuracy for the entire cohort were 0.875 (0.719-0.962), 100% (23/23), 75% (9/12), 88.5% (23/26), 100% (9/9), and 91.4% (32/35), respectively. The ADC and D showed similar diagnostic accuracy in distinguishing between ccRCCs and fat poor AMLs. The IVIM-derived parameters were better than ADC in discriminating non-ccRCCs from fat poor AMLs.

  6. 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.

  7. Application Of Hydrological Models In Poorly Gauged Watersheds A Review Of The Usage Of The Soil And Water Assessment Tool SWAT In Kenya

    Directory of Open Access Journals (Sweden)

    Wambugu Mwangi

    2017-08-01

    Full Text Available 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 inconsistent river monitoring data. Under data-scarce conditions and with the increasing land use intensification and urbanization modelling approaches become a useful tool in planning and management of water resources. In this paper we review the application and usability of the Soil and Water Assessment Tool SWAT model in conventional planning practice in the management of water resources is poorly-gauged tropical watersheds of Kenya. We assess the technical implications of the model in Intergrated Water Resources management IWRM and its applicability as a planning and management tool for water resources in the era of climate change.

  8. 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

  9. 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

  10. A systematic evaluation of solubility enhancing excipients to enable the generation of permeability data for poorly soluble compounds in Caco-2 model.

    Science.gov (United States)

    Shah, Devang; Paruchury, Sundeep; Matta, Muralikrishna; Chowan, Gajendra; Subramanian, Murali; Saxena, Ajay; Soars, Matthew G; Herbst, John; Haskell, Roy; Marathe, Punit; Mandlekar, Sandhya

    2014-01-01

    The study presented here identified and utilized a panel of solubility enhancing excipients to enable the generation of flux data in the Human colon carcinoma (Caco-2) system for compounds with poor solubility. Solubility enhancing excipients Dimethyl acetamide (DMA) 1 % v/v, polyethylene glycol (PEG) 400 1% v/v, povidone 1% w/v, poloxamer 188 2.5% w/v and bovine serum albumin (BSA) 4% w/v did not compromise Caco-2 monolayer integrity as assessed by trans-epithelial resistance measurement (TEER) and Lucifer yellow (LY) permeation. Further, these excipients did not affect P-glycoprotein (P-gp) mediated bidirectional transport of digoxin, permeabilities of high (propranolol) or low permeability (atenolol) compounds, and were found to be inert to Breast cancer resistant protein (BCRP) mediated transport of cladribine. This approach was validated further using poorly soluble tool compounds, atazanavir (poloxamer 188 2.5% w/v) and cyclosporine A (BSA 4% w/v) and also applied to new chemical entity (NCE) BMS-A in BSA 4% w/v, for which Caco-2 data could not be generated using the traditional methodology due to poor solubility (solubility of atazanavir by >8 fold whereas BSA 4% w/v increased the solubility of cyclosporine A and BMS-A by >2-4 fold thereby enabling permeability as well as efflux liability estimation in the Caco-2 model with reasonable recovery values. To conclude, addition of excipients such as poloxamer 188 2.5% w/v and BSA 4% w/v to HBSS leads to a significant improvement in the solubility of the poorly soluble compounds resulting in enhanced recoveries without modulating transporter-mediated efflux, expanding the applicability of Caco-2 assays to poorly soluble compounds.

  11. Elevated neutrophil and monocyte counts in peripheral blood are associated with poor survival in patients with metastatic melanoma: a prognostic model

    DEFF Research Database (Denmark)

    Schmidt, H; Bastholt, L; Geertsen, P

    2005-01-01

    factors in univariate analyses. Subsequently, a multivariate Cox's regression analysis identified elevated LDH (Pperformance status of 2 (P=0.008, hazard ratio 1.6) as independent prognostic factors for poor survival...... of several phase II protocols and the majority received treatment with intermediate dose subcutaneous IL-2 and interferon-alpha. Neutrophil and monocyte counts, lactate dehydrogenase (LDH), number of metastatic sites, location of metastases and performance status were all statistically significant prognostic...... survival of 12.6 months (95% confidence interval (CI), 11.4-13.8), 6.0 months (95% CI, 4.8-7.2) and 3.4 months (95% CI, 1.2-5.6), respectively. The low-risk group encompassed the majority of long-term survivors, whereas the patients in the high-risk group with a very poor prognosis should probably...

  12. Modelling saline intrusion for repository performance assessment

    International Nuclear Information System (INIS)

    Jackson, C.P.

    1989-04-01

    UK Nirex Ltd are currently considering the possibility of disposal of radioactive waste by burial in deep underground repositories. The natural pathway for radionuclides from such a repository to return to Man's immediate environment (the biosphere) is via groundwater. Thus analyses of the groundwater flow in the neighbourhood of a possible repository, and consequent radionuclide transport form an important part of a performance assessment for a repository. Some of the areas in the UK that might be considered as possible locations for a repository are near the coast. If a repository is located in a coastal region seawater may intrude into the groundwater flow system. As seawater is denser than fresh water buoyancy forces acting on the intruding saline water may have significant effects on the groundwater flow system, and consequently on the time for radionuclides to return to the biosphere. Further, the chemistry of the repository near-field may be strongly influenced by the salinity of the groundwater. It is therefore important for Nirex to have a capability for reliably modelling saline intrusion to an appropriate degree of accuracy in order to make performance assessments for a repository in a coastal region. This report describes work undertaken in the Nirex Research programme to provide such a capability. (author)

  13. 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

  14. 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.

  15. 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...

  16. [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.

  17. 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

  18. Baking oven improvement by performance modelling

    Energy Technology Data Exchange (ETDEWEB)

    1994-04-01

    The first phase of the project included both the derivation of an oven model and the development of a portable, rapid-response heat-flux sensor. Heat flux (defined as the instantaneous rate of heat flow per unit at the surface of the baking biscuit and expressed in W/cm[sup 2]) has been shown to be a more useful measure of oven performance than temperature alone. Fixed-point heat-flux sensors have already been developed and marketed, but a need was expressed at the start of this project for a travelling sensor which could be used to construct a more detailed picture of heat-flux variation in an oven. The travelling monitor developed can be used to measure variations in the heat flux experienced at the surface of products being baked in a travelling oven, both when oven conditions are fixed and when they are varied. It can also be used to identify the optimum locations within an oven for fixed heat-flux probes. It has been used effectively throughout the project for both purposes. Fuel savings of 18% and 21%, respectively, were achieved with two ovens. (author)

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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....

  4. 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

  5. Sesquiterpene lactone mix as a diagnostic tool for Asteraceae allergic contact dermatitis: chemical explanation for its poor performance and Sesquiterpene lactone mix II as a proposed improvement.

    Science.gov (United States)

    Jacob, Mathias; Brinkmann, Jürgen; Schmidt, Thomas J

    2012-05-01

    Two preparations are currently in use for the diagnosis of allergic contact dermatitis caused by Asteraceae: (i) Sesquiterpene lactone (SL) mix [three pure sesquiterpene lactones (STLs)], whose use has been questioned, owing to an insufficient rate of true-positive results; and (ii) Compositae mix, consisting of five Asteraceae extracts, which is problematic because of lack of standardization and questionable reproducibility. To analyse the reasons for the narrow sensitivity of SL mix from a chemoinformatic point of view, and to propose a solution by rational selection of alternative constituents for a new SL mix II covering a broader cohort of allergic patients. Structural and biological information on allergenic STLs was retrieved from databases and the literature, and molecular modelling and chemoinformatic computations were performed. An explanation for the insufficient hit rate of SL mix is that the three constituents possess extremely similar molecular structures/properties and do not represent well the structural diversity of allergenic STLs. STLs that are known as constituents of Compositae mix plants show much a wider diversity, which explains the higher positive rate. On the basis of their positions in chemical property space, a new collection of STLs that more evenly cover the overall structural diversity spectrum is proposed. SL mix II is likely to detect a larger number of patients sensitized to Asteraceae. © 2012 John Wiley & Sons A/S.

  6. Sustaining Team Performance: A Systems Model\\

    Science.gov (United States)

    1979-07-31

    member performance of specific behaviors" ( Nivea et al., 1978, p. 59). They have identified four major performance categories, and several performance...within the fire direction center several artillerymen work additively. The number of men in the fire direction center does not add steps to the sequence...Instructional strategies for training men of high and low aptitude. HumRRO-TR-73-10. Alexandria, VA: Human Resources Organization, April 1973. Blum, M.L. and

  7. [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

  8. Biomechanical modelling and evaluation of construction jobs for performance improvement.

    Science.gov (United States)

    Parida, Ratri; Ray, Pradip Kumar

    2012-01-01

    Occupational risk factors, such as awkward posture, repetition, lack of rest, insufficient illumination and heavy workload related to construction-related MMH activities may cause musculoskeletal disorders and poor performance of the workers, ergonomic design of construction worksystems was a critical need for improving their health and safety wherein a dynamic biomechanical models were required to be empirically developed and tested at a construction site of Tata Steel, the largest steel making company of India in private sector. In this study, a comprehensive framework is proposed for biomechanical evaluation of shovelling and grinding under diverse work environments. The benefit of such an analysis lies in its usefulness in setting guidelines for designing such jobs with minimization of risks of musculoskeletal disorders (MSDs) and enhancing correct methods of carrying out the jobs leading to reduced fatigue and physical stress. Data based on direct observations and videography were collected for the shovellers and grinders over a number of workcycles. Compressive forces and moments for a number of segments and joints are computed with respect to joint flexion and extension. The results indicate that moments and compressive forces at L5/S1 link are significant for shovellers while moments at elbow and wrist are significant for grinders.

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

    Directory of Open Access Journals (Sweden)

    Jorge Sánchez

    2016-03-01

    Conclusion: 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.

  10. 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

  11. 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

  12. 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.

  13. 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....

  14. 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.

  15. Modelling Flat Spring performance using FEA

    International Nuclear Information System (INIS)

    Fatola, B O; Keogh, P; Hicks, B

    2009-01-01

    This paper reports how the stiffness of a Flat Spring can be predicted using nonlinear Finite Element Analysis (FEA). The analysis of a Flat Spring is a nonlinear problem involving contact mechanics, geometric nonlinearity and material property nonlinearity. Research has been focused on improving the accuracy of the model by identifying and exploring the significant assumptions contributing to errors. This paper presents results from some of the models developed using FEA software. The validation process is shown to identify where improvements can be made to the model assumptions to increase the accuracy of prediction. The goal is to achieve an accuracy level of ±10 % as the intention is to replace practical testing with FEA modelling, thereby reducing the product development time and cost. Results from the FEA models are compared with experimental results to validate the accuracy.

  16. A metabolic way to investigate related hurdles causing poor bioavailability in oral delivery of isoacteoside in rats employing ultrahigh-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Cui, Qingling; Pan, Yingni; Yan, Xiaowei; Qu, Bao; Liu, Xiaoqiu; Xiao, Wei

    2017-02-28

    Isoacteoside (ISAT), a phenylethanoid glycoside that acts as the principal bioactive component in traditional Chinese medicines, possesses broad pharmacological effects such as neuroprotective, antihypertensive and hepatoprotective activities. However, its pharmaceutical development has been severely limited due to the poor oral bioavailability. It is essential and significant to investigate related hurdles leading to the poor bioavailability of isoacteoside. Whole animal metabolism studies were conducted in rats, followed by metabolic mechanism including gastrointestinal stability, intestinal flora metabolism and intestinal enzyme metabolism employing the powerful method ultrahigh-performance liquid chromatography combined with quadrupole time-of-flight tandem mass spectrometry (UPLC/QTOF-MS/MS). A simple, rapid and sensitive method has been developed which comprehensively revealed the underlying cause of poor bioavailability of ISAT in a metabolic manner. The prototype of ISAT and its combined metabolites have not been detected in plasma. Furthermore, the residual content of the parent compound in in vitro experiments was approximately 59%, 5% and barely none in intestinal bacteria, intestinal S9 and simulated intestinal juice at 6 h, respectively. The present work has demonstrated that the factors causing the poor bioavailability of isoacteoside should be attributed to the metabolism. In general, the metabolism that resulted from intestinal flora and intestinal enzymes were predominant reasons giving rise to the poor bioavailability of ISAT, which also suggested that metabolites might be responsible for the excellent pharmacological effect of ISAT. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  17. 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

  18. The Gaia-ESO Survey: Separating disk chemical substructures with cluster models. Evidence of a separate evolution in the metal-poor thin disk

    Science.gov (United States)

    Rojas-Arriagada, A.; Recio-Blanco, A.; de Laverny, P.; Schultheis, M.; Guiglion, G.; Mikolaitis, Š.; Kordopatis, G.; Hill, V.; Gilmore, G.; Randich, S.; Alfaro, E. J.; Bensby, T.; Koposov, S. E.; Costado, M. T.; Franciosini, E.; Hourihane, A.; Jofré, P.; Lardo, C.; Lewis, J.; Lind, K.; Magrini, L.; Monaco, L.; Morbidelli, L.; Sacco, G. G.; Worley, C. C.; Zaggia, S.; Chiappini, C.

    2016-02-01

    Context. Recent spectroscopic surveys have begun to explore the Galactic disk system on the basis of large data samples, with spatial distributions sampling regions well outside the solar neighborhood. In this way, they provide valuable information for testing spatial and temporal variations of disk structure kinematics and chemical evolution. Aims: The main purposes of this study are to demonstrate the usefulness of a rigorous mathematical approach to separate substructures of a stellar sample in the abundance-metallicity plane, and provide new evidence with which to characterize the nature of the metal-poor end of the thin disk sequence. Methods: We used a Gaussian mixture model algorithm to separate in the [Mg/Fe] vs. [Fe/H] plane a clean disk star subsample (essentially at RGC -0.25 dex) highlight a change in the slope at solar metallicity. This holds true at different radial regions of the Milky Way. The distribution of Galactocentric radial distances of the metal-poor part of the thin disk ([Fe/H] Cambridge Astronomy Survey Unit (CASU) at the Institute of Astronomy, University of Cambridge, and by the FLAMES/UVES reduction team at INAF/Osservatorio Astrofisico di Arcetri. These data have been obtained from the Gaia-ESO Survey Data Archive, prepared and hosted by the Wide Field Astronomy Unit, Institute for Astronomy, University of Edinburgh, which is funded by the UK Science and Technology Facilities Council.

  19. 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.

  20. The CREATIVE Decontamination Performance Evaluation Model

    National Research Council Canada - National Science Library

    Shelly, Erin E

    2008-01-01

    The project objective is to develop a semi-empirical, deterministic model to characterize and predict laboratory-scale decontaminant efficacy and hazards for a range of: chemical agents (current focus on HD...

  1. 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...

  2. Modelling of Supercapacitors: Factors Influencing Performance

    OpenAIRE

    Kroupa, M; Offer, GJ; Kosek, J

    2016-01-01

    The utilizable capacitance of Electrochemical Double Layer Capacitors (EDLCs) is a function of the frequency at which they are operated and this is strongly dependent on the construction and physical parameters of the device. We simulate the dynamic behavior of an EDLC using a spatially resolved model based on the porous electrode theory. The model of Verbrugge and Liu (J. Electrochem. Soc. 152, D79 (2005)) was extended with a dimension describing the transport into the carbon particle pores....

  3. 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

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. [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, pperformance (0.43 vs 0.27, 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.

  9. 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...

  10. 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

    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...... 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...

  11. Abstract 20854: A Tale of Self-Fulfilling Prophecies in Out-of-Hospital Cardiac Arrest: Emergency Medical Technicians Deliberately Perform Substandard CPR When Anticipating Poor Prognosis

    DEFF Research Database (Denmark)

    Bødtker, Henrik; Klausen, Troels M; Lauridsen, Kasper G

    2017-01-01

    ) if they believe resuscitation to be futile. Furthermore, to investigate if different patient and resuscitation attempt characteristics result in EMTs deliberately performing substandard CPR.Methods: This was a cross-sectional questionnaire survey study conducted in 2016 through 2017 including EMTs from a Danish...... and compressions). Overall, 22% and 51% would perform substandard CPR if the patient were 80 or 90 years old respectively, 46% if the patient was living in a nursing home and up to 31% due to comorbidity such as cancer. EMTs (51%) would deliberately perform substandard CPR in case of on-going bystander CPR >20...... minutes. EMTs (72%) felt competent to terminate resuscitation, but only 9% knew international termination guidelines.Conclusion: EMTs delay start of resuscitation if they anticipate resuscitation to be futile. Furthermore, they deliberately perform substandard CPR based on controversial patient...

  12. 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 ...

  13. HANDOVER MANAGEABILITY AND PERFORMANCE MODELING IN

    African Journals Online (AJOL)

    SOFTLINKS DIGITAL

    and Corporate Information Systems: A Proactive Mitigation. Response Model. 1 ... known malware variants, and more than ... has defined authentication as the process of identifying ... providing protection via Access Controls,. Encryption and ... to use their technical prowess to teach .... Developing and distributing approved.

  14. 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

  15. HANDOVER MANAGEABILITY AND PERFORMANCE MODELING IN

    African Journals Online (AJOL)

    SOFTLINKS DIGITAL

    Software is better modelled with the use of UML diagrams like use cases which ... analysis and design according to [1] is to transform the 'black .... The system request the user to enter his/her user_id .... The corresponding changes are saved.

  16. Mathematical modeling of optical glazing performance

    NARCIS (Netherlands)

    Nijnatten, van P.A.; Wittwer, V.; Granqvist, C.G.; Lampert, C.M.

    1994-01-01

    Mathematical modelling can be a powerful tool in the design and optimalization of glazing. By calculation, the specifications of a glazing design and the optimal design parameters can be predicted without building costly prototypes first. Furthermore, properties which are difficult to measure, like

  17. 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

  18. High-performance phase-field modeling

    KAUST Repository

    Vignal, Philippe; Sarmiento, Adel; Cortes, Adriano Mauricio; Dalcin, L.; Collier, N.; Calo, Victor M.

    2015-01-01

    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.

  19. 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...... often rely heavily on services provided by governments. We test this proposition using micro-level survey data from the Afrobaromenter. Multilevel regressions across 18 countries show that poor people are much more prone to experience having to pay bribes to government officials....

  20. Atmospheric statistical dynamic models. Model performance: the Lawrence Livermore Laboratoy Zonal Atmospheric Model

    International Nuclear Information System (INIS)

    Potter, G.L.; Ellsaesser, H.W.; MacCracken, M.C.; Luther, F.M.

    1978-06-01

    Results from the zonal model indicate quite reasonable agreement with observation in terms of the parameters and processes that influence the radiation and energy balance calculations. The model produces zonal statistics similar to those from general circulation models, and has also been shown to produce similar responses in sensitivity studies. Further studies of model performance are planned, including: comparison with July data; comparison of temperature and moisture transport and wind fields for winter and summer months; and a tabulation of atmospheric energetics. Based on these preliminary performance studies, however, it appears that the zonal model can be used in conjunction with more complex models to help unravel the problems of understanding the processes governing present climate and climate change. As can be seen in the subsequent paper on model sensitivity studies, in addition to reduced cost of computation, the zonal model facilitates analysis of feedback mechanisms and simplifies analysis of the interactions between processes

  1. Individualized Biomathematical Modeling of Fatigue and Performance

    Science.gov (United States)

    2008-05-29

    Interactions and Transitions 53 New Discoveries , Inventions, or Patent Disclosures 56 FA9550-06-1-0055 Individualized Biomathematical Modeling of Fatigue...Old Dominion University, not supported on grant) Daniel J. Mollicone, Ph.D. ( Pulsar Informatics, Inc., not supported on grant) Christopher G...Mott, M.S. ( Pulsar Informatics, Inc., not supported on grant) Erik Olofsen, M.S. (Leiden University, the Netherlands, not supported on grant

  2. Studies on dissolution enhancement and mathematical modeling of drug release of a poorly water-soluble drug using water-soluble carriers.

    Science.gov (United States)

    Ahuja, Naveen; Katare, Om Prakash; Singh, Bhupinder

    2007-01-01

    Role of various water-soluble carriers was studied for dissolution enhancement of a poorly soluble model drug, rofecoxib, using solid dispersion approach. Diverse carriers viz. polyethylene glycols (PEG 4000 and 6000), polyglycolized fatty acid ester (Gelucire 44/14), polyvinylpyrollidone K25 (PVP), poloxamers (Lutrol F127 and F68), polyols (mannitol, sorbitol), organic acid (citric acid) and hydrotropes (urea, nicotinamide) were investigated for the purpose. Phase-solubility studies revealed AL type of curves for each carrier, indicating linear increase in drug solubility with carrier concentration. The sign and magnitude of the thermodynamic parameter, Gibbs free energy of transfer, indicated spontaneity of solubilization process. All the solid dispersions showed dissolution improvement vis-à-vis pure drug to varying degrees, with citric acid, PVP and poloxamers as the most promising carriers. Mathematical modeling of in vitro dissolution data indicated the best fitting with Korsemeyer-Peppas model and the drug release kinetics primarily as Fickian diffusion. Solid state characterization of the drug-poloxamer binary system using XRD, FTIR, DSC and SEM techniques revealed distinct loss of drug crystallinity in the formulation, ostensibly accounting for enhancement in dissolution rate.

  3. 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,…

  4. 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.

  5. Accounting for the Poor

    OpenAIRE

    Robert M. Townsend

    2013-01-01

    Economists and other social scientists have long tried to understand the nature of poverty and how poor people make decisions. For example, T.W. Schultz, a Nobel Laureate, former professor of economics at the University of Chicago, and former president of the American Economic Association, spent his career working in development and agricultural economics. In his 1980 Nobel Prize acceptance speech, Schultz suggests that there is some accounting for the behavior of the poor in agriculture. "Fa...

  6. Cognitive performance after mild traumatic brain injury: the impact of poor effort on test results and its relation to distress, personality and litigation.

    NARCIS (Netherlands)

    Stulemeijer, M.; Andriessen, T.M.J.C.; Brauer, J.M.; Vos, P.E.; Werf, S.P. van der

    2007-01-01

    PRIMARY OBJECTIVE: To compare consecutive Mild Traumatic Brain Injury (MTBI) patients with and without adequate effort on cognitive performance, litigation status, fatigue, distress and personality. RESEARCH DESIGN: (Neuro)psychological assessment was done 6 months post-injury in 110 patients from a

  7. 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.

  8. 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

  9. 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

  10. 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

  11. 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...

  12. Mathematical Modeling Predicts that Increased HSV-2 Shedding in HIV-1 Infected Persons Is Due to Poor Immunologic Control in Ganglia and Genital Mucosa.

    Directory of Open Access Journals (Sweden)

    Joshua T Schiffer

    Full Text Available A signature feature of HIV infection is poor control of herpes virus infections, which reactivate from latency and cause opportunistic infections. While the general mechanism underlying this observation is deficient CD4+T-cell function, it is unknown whether increased severity of herpes virus infections is due primarily to poor immune control in latent or lytic sites of infection, or whether CD4+ immunodeficiency leads to more critical downstream deficits in humoral or cell-mediated immunologic responses. Here we compare genital shedding patterns of herpes simplex virus-2 (HSV-2 in 98 HIV infected and 98 HIV uninfected men matched on length of infection, HSV-1 serostatus and nationality. We demonstrate that high copy HSV-2 shedding is more frequent in HIV positive men, particularly in participants with CD4+ T-cell count <200/μL. Genital shedding is more frequent due to higher rate of shedding episodes, as well as a higher proportion of prolonged shedding episodes. Peak episode viral load was not found to differ between HIV infected and uninfected participants regardless of CD4+ T-cell count. We simulate a mathematical model which recapitulates these findings and identifies that rate of HSV-2 release from neural tissue increases, duration of mucosal cytolytic immune protection decreases, and cell-free viral lifespan increases in HIV infected participants. These results suggest that increased HSV-2 shedding in HIV infected persons may be caused by impaired immune function in both latent and lytic tissue compartments, with deficits in clearance of HSV-2 infected cells and extracellular virus.

  13. Characterization uncertainty and its effects on models and performance

    International Nuclear Information System (INIS)

    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

  14. 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

  15. New model performance index for engineering design of control systems

    Science.gov (United States)

    1970-01-01

    Performance index includes a model representing linear control-system design specifications. Based on a geometric criterion for approximation of the model by the actual system, the index can be interpreted directly in terms of the desired system response model without actually having the model's time response.

  16. Advanced Performance Modeling with Combined Passive and Active Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Dovrolis, Constantine [Georgia Inst. of Technology, Atlanta, GA (United States); Sim, Alex [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-04-15

    To improve the efficiency of resource utilization and scheduling of scientific data transfers on high-speed networks, the "Advanced Performance Modeling with combined passive and active monitoring" (APM) project investigates and models a general-purpose, reusable and expandable network performance estimation framework. The predictive estimation model and the framework will be helpful in optimizing the performance and utilization of networks as well as sharing resources with predictable performance for scientific collaborations, especially in data intensive applications. Our prediction model utilizes historical network performance information from various network activity logs as well as live streaming measurements from network peering devices. Historical network performance information is used without putting extra load on the resources by active measurement collection. Performance measurements collected by active probing is used judiciously for improving the accuracy of predictions.

  17. Analytic Ballistic Performance Model of Whipple Shields

    Science.gov (United States)

    Miller, J. E.; Bjorkman, M. D.; Christiansen, E. L.; Ryan, S. J.

    2015-01-01

    The dual-wall, Whipple shield is the shield of choice for lightweight, long-duration flight. The shield uses an initial sacrificial wall to initiate fragmentation and melt an impacting threat that expands over a void before hitting a subsequent shield wall of a critical component. The key parameters to this type of shield are the rear wall and its mass which stops the debris, as well as the minimum shock wave strength generated by the threat particle impact of the sacrificial wall and the amount of room that is available for expansion. Ensuring the shock wave strength is sufficiently high to achieve large scale fragmentation/melt of the threat particle enables the expansion of the threat and reduces the momentum flux of the debris on the rear wall. Three key factors in the shock wave strength achieved are the thickness of the sacrificial wall relative to the characteristic dimension of the impacting particle, the density and material cohesion contrast of the sacrificial wall relative to the threat particle and the impact speed. The mass of the rear wall and the sacrificial wall are desirable to minimize for launch costs making it important to have an understanding of the effects of density contrast and impact speed. An analytic model is developed here, to describe the influence of these three key factors. In addition this paper develops a description of a fourth key parameter related to fragmentation and its role in establishing the onset of projectile expansion.

  18. 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.)

  19. 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...

  20. 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.

  1. 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

  2. Vitamin D and parathyroid hormone are associated with gait instability and poor balance performance in mid-age to older aged women.

    Science.gov (United States)

    Bird, Marie-Louise; El Haber, Natalie; Batchelor, Frances; Hill, Keith; Wark, John D

    2018-01-01

    Vitamin D status and parathyroid hormone (PTH) levels influence the risk of accidental falls in older people, but the mechanisms underlying this effect remain unclear. Investigate the relationship between circulating PTH and 25 hydroxyvitamin D (25-OHD) levels and clinical tests of gait stability and balance as physical fall risk factors. We hypothesized that high levels of PTH and low 25-OHD levels would be significantly associated with gait stability and decreased balance performance. Observational cohort study. Australian community. 119 healthy, ambulatory female twin adults aged 47-80 years residing in Victoria, Australia. Serum PTH and 25-OHD levels with clinical tests of gait stability [double support duration (DSD)] and dynamic balance (Step Test). Associations were investigated by regression analysis and by comparing groups divided by tertiles of PTH (4.9pmol/L) and 25-OHD (75 nmol/L) using analysis of variance. Serum PTH was associated positively with DSD, with an increase of 10.6-15.7% when the mid and highest PTH tertiles were compared to the lowest tertile (p <0.025) when 25-OHD was included in the regression analysis. 25-OHD was significantly associated with DSD (greater by 10.6-11.1% when lowest and mid-tertiles compared with the highest 25-OHD tertile) (p <0.025) and dynamic balance (better performance by 12.6% in the highest compared with the lowest 25OHD tertile) (p <0.025). These findings reveal an important new relationship between parathyroid hormone and gait stability parameters and add to understanding of the role of 25-OHD in motor control of gait and dynamic balance in community-dwelling women across a wide age span. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Young adults perinatally infected with HIV perform more poorly on measures of executive functioning and motor speed than ethnically matched healthy controls.

    Science.gov (United States)

    Willen, Elizabeth J; Cuadra, Anai; Arheart, Kristopher L; Post, M J D; Govind, Varan

    2017-03-01

    Perinatal HIV is associated with significant neurocognitive morbidities, but few studies have examined cognitive impact of early HIV infection on patients surviving to adulthood. The purpose of this study was to evaluate neurocognitive outcomes among a cohort of perinatally infected young adults. Individuals between the ages of 18 and 24 with perinatal infection were recruited for this cross-sectional study along with similarly aged healthy controls. Participants completed an MRI and brief neuropsychological assessment battery. Multivariate analysis of covariance controlling for age, gender, race/ethnicity, and education was completed to detect differences between the HIV+ and control groups. Multivariable linear regression was performed to assess HIV-associated factors potentially impacting neuropsychological findings among the HIV+ group. Twenty-nine HIV+ young adults and 13 healthy controls were included in the study. After adjusting for age and sociodemographic variables, the HIV+ group scored lower on attention/working memory (Digit Span (p = .008) and Letter-Number Sequencing (p = .038)), set-shifting (DKEFS Trail Making Test Condition 4 (p = .026) and motor speed (DKEFS Trail Making Test Condition 5 (p = .003)). For the HIV+ group, nadir CD4 was associated with better Letter-Number Sequencing score (p = .029) and use of highly active antiretroviral therapy was associated with better performance on Category Fluency (p = .040). After controlling for sociodemographic variables, executive dysfunction persists among young adults with perinatal HIV infection in comparison to controls. Future studies to further elucidate the impact of executive dysfunction on independent living and functional outcomes are indicated.

  4. Carbon-enhanced metal-poor stars in SDSS/Segue. II. Comparison of CEMP-star frequencies with binary population-synthesis models

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Sun [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Suda, Takuma [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan); Beers, Timothy C. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Stancliffe, Richard J., E-mail: yslee@nmsu.edu [Argelander-Institut für Astronomie, Auf dem Hügel 71, D-53121 Bonn (Germany)

    2014-06-20

    We present a comparison of the frequencies of carbon-enhanced metal-poor (CEMP) giant and main-sequence turnoff (MSTO) stars with predictions from binary population-synthesis models involving asymptotic giant-branch (AGB) mass transfer. The giant and MSTO stars are selected from the Sloan Digital Sky Survey and the Sloan Extension for Galactic Understanding and Exploration. We consider two initial mass functions (IMFs)—a Salpeter IMF, and a mass function with a characteristic mass of 10 M {sub ☉}. For giant stars, the comparison indicates a good agreement between the observed CEMP frequencies and the AGB binary model using a Salpeter IMF for [Fe/H] > – 1.5, and a characteristic mass of 10 M {sub ☉} for [Fe/H] < – 2.5. This result suggests that the IMF shifted from high- to low-mass dominated in the early history of the Milky Way, which appears to have occurred at a 'chemical time' between [Fe/H] =–2.5 and [Fe/H] =–1.5. The CEMP frequency for the turnoff stars with [Fe/H] < – 3.0 is much higher than the AGB model prediction from the high-mass IMF, supporting the previous assertion that one or more additional mechanisms, not associated with AGB stars, are required for the production of carbon-rich material below [Fe/H] =–3.0. We also discuss possible effects of first dredge-up and extra mixing in red giants and internal mixing in turnoff stars on the derived CEMP frequencies.

  5. Performance Modeling of Communication Networks with Markov Chains

    CERN Document Server

    Mo, Jeonghoon

    2010-01-01

    This book is an introduction to Markov chain modeling with applications to communication networks. It begins with a general introduction to performance modeling in Chapter 1 where we introduce different performance models. We then introduce basic ideas of Markov chain modeling: Markov property, discrete time Markov chain (DTMe and continuous time Markov chain (CTMe. We also discuss how to find the steady state distributions from these Markov chains and how they can be used to compute the system performance metric. The solution methodologies include a balance equation technique, limiting probab

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. Switching performance of OBS network model under prefetched real traffic

    Science.gov (United States)

    Huang, Zhenhua; Xu, Du; Lei, Wen

    2005-11-01

    Optical Burst Switching (OBS) [1] is now widely considered as an efficient switching technique in building the next generation optical Internet .So it's very important to precisely evaluate the performance of the OBS network model. The performance of the OBS network model is variable in different condition, but the most important thing is that how it works under real traffic load. In the traditional simulation models, uniform traffics are usually generated by simulation software to imitate the data source of the edge node in the OBS network model, and through which the performance of the OBS network is evaluated. Unfortunately, without being simulated by real traffic, the traditional simulation models have several problems and their results are doubtable. To deal with this problem, we present a new simulation model for analysis and performance evaluation of the OBS network, which uses prefetched IP traffic to be data source of the OBS network model. The prefetched IP traffic can be considered as real IP source of the OBS edge node and the OBS network model has the same clock rate with a real OBS system. So it's easy to conclude that this model is closer to the real OBS system than the traditional ones. The simulation results also indicate that this model is more accurate to evaluate the performance of the OBS network system and the results of this model are closer to the actual situation.

  11. 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

  12. 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

  13. Statistical and Machine Learning Models to Predict Programming Performance

    OpenAIRE

    Bergin, Susan

    2006-01-01

    This thesis details a longitudinal study on factors that influence introductory programming success and on the development of machine learning models to predict incoming student performance. Although numerous studies have developed models to predict programming success, the models struggled to achieve high accuracy in predicting the likely performance of incoming students. Our approach overcomes this by providing a machine learning technique, using a set of three significant...

  14. 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…

  15. Increased functional connectivity in the default mode network in mild cognitive impairment: a maladaptive compensatory mechanism associated with poor semantic memory performance.

    Science.gov (United States)

    Gardini, Simona; Venneri, Annalena; Sambataro, Fabio; Cuetos, Fernando; Fasano, Fabrizio; Marchi, Massimo; Crisi, Girolamo; Caffarra, Paolo

    2015-01-01

    Semantic memory decline and changes of default mode network (DMN) connectivity have been reported in mild cognitive impairment (MCI). Only a few studies, however, have investigated the role of changes of activity in the DMN on semantic memory in this clinical condition. The present study aimed to investigate more extensively the relationship between semantic memory impairment and DMN intrinsic connectivity in MCI. Twenty-one MCI patients and 21 healthy elderly controls matched for demographic variables took part in this study. All participants underwent a comprehensive semantic battery including tasks of category fluency, visual naming and naming from definition for objects, actions and famous people, word-association for early and late acquired words and reading. A subgroup of the original sample (16 MCI patients and 20 healthy elderly controls) was also scanned with resting state functional magnetic resonance imaging and DMN connectivity was estimated using a seed-based approach. Compared with healthy elderly, patients showed an extensive semantic memory decline in category fluency, visual naming, naming from definition, words-association, and reading tasks. Patients presented increased DMN connectivity between the medial prefrontal regions and the posterior cingulate and between the posterior cingulate and the parahippocampus and anterior hippocampus. MCI patients also showed a significant negative correlation of medial prefrontal gyrus connectivity with parahippocampus and posterior hippocampus and visual naming performance. Our findings suggest that increasing DMN connectivity may contribute to semantic memory deficits in MCI, specifically in visual naming. Increased DMN connectivity with posterior cingulate and medio-temporal regions seems to represent a maladaptive reorganization of brain functions in MCI, which detrimentally contributes to cognitive impairment in this clinical population.

  16. 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.

  17. 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.

  18. 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

  19. FARMLAND: Model description and evaluation of model performance

    Energy Technology Data Exchange (ETDEWEB)

    Attwood, C; Fayers, C; Mayall, A; Brown, J; Simmonds, J R [National Radiological Protection Board, Chilton (United Kingdom)

    1996-09-01

    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.

  20. 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.

  1. 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.

  2. 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 ...

  3. A poor performance in comprehensive geriatric assessment is associated with increased fall risk in elders with hypertension: a cross-sectional study.

    Science.gov (United States)

    Chu, Jiao-Jiao; Chen, Xu-Jiao; Shen, Shan-Shan; Zhang, Xue-Feng; Chen, Ling-Yan; Zhang, Jing-Mei; He, Jing; Zhao, Jun-Feng

    2015-03-01

    Fall and serious fall injuries have become a major health concern for elders. Many factors including blood pressure and anti-hypertensive medication application were reported as hazards of fall. The purpose of this study was to determine if age related systemic functional decline related with increased fall risks in elderly patients with hypertension. A total of 342 elderly hypertension patients (age 79.5 ± 6.7 years, male 63.8%) were recruited to the study. Comprehensive geriatric assessment (CGA), including measurements about activity of daily living (ADL), nutrition, cognition, depression, numbers of prescription medication and number of clinical diagnosis, was conducted to evaluate the physical and mental status of each participants. Fall risk was evaluated by Morse fall scale, Tinetti performance oriented mobility assessment (POMA) and history of fall in the recent year. Participants were grouped into tertiles according to CGA score. Correlation between CGA and fall risk was analyzed through SPSS 18.0. Participants with higher CGA score were likely to be older, had a lower body mass index (BMI), and a higher prevalence of cardiovascular disease, chronic obstructive pulmonary disease (COPD), cerebrovascular disease and osteoarthropathia. Participants in higher tertile of CGA score got increased prevalence of fall risk than those in lower tertile (P fall scale (P fall risks. After adjusting age, BMI, benzodiazepine use, cardiovascular disease, cerebrovascular disease, COPD and osteoarthropathia, both history of fall in the recent year and rising Morse fall scale were significantly associated with ADL impairment (OR: 2.748, 95%CI: 1.598-4.725), (OR: 3.310, 95%CI: 1.893-5.788). Decreased Tinetti POMA score was associated with Mini-Mental State Examination (MMSE) (OR: 4.035, 95%CI: 2.100-7.751), ADL (OR: 2.380, 95%CI: 1.357-4.175) and shortened MNA form (MNA-SF) impairment (OR: 2.692, 95%CI: 1.147-6.319). In elderly adults with hypertension, impaired physical and

  4. 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

  5. Modelling Client Satisfaction Levels: The Impact of Contractor Performance

    Directory of Open Access Journals (Sweden)

    Robby Soetanto

    2012-11-01

    Full Text Available The performance of contractors is known to be a key determinant of client satisfaction.Here, using factor analysis, clients’ satisfaction is defined in several dimensions. Based onclients’ assessment of contractor performance, a number of satisfaction models developedusing the multiple regression (MR technique are presented. The models identify arange of variables encompassing contractor performance, project performance and respondent(i.e. client attributes as useful predictors of satisfaction levels. Contractor performanceattributes were found to be of utmost importance indicating that clientsatisfaction levels are mainly dependent on the performance of the contractor. Furthermore,findings suggest that subjectivity is to some extent prevalent in clients’ performanceassessment. The models demonstrate accurate and reliable predictive power as confirmedby validation tests. Contractors could use the models to help improve their performanceleading to more satisfied clients. This would also promote the development ofharmonious working relationships within the construction project coalition.

  6. Performance modeling of neighbor discovery in proactive routing protocols

    Directory of Open Access Journals (Sweden)

    Andres Medina

    2011-07-01

    Full Text Available It is well known that neighbor discovery is a critical component of proactive routing protocols in wireless ad hoc networks. However there is no formal study on the performance of proposed neighbor discovery mechanisms. This paper provides a detailed model of key performance metrics of neighbor discovery algorithms, such as node degree and the distribution of the distance to symmetric neighbors. The model accounts for the dynamics of neighbor discovery as well as node density, mobility, radio and interference. The paper demonstrates a method for applying these models to the evaluation of global network metrics. In particular, it describes a model of network connectivity. Validation of the models shows that the degree estimate agrees, within 5% error, with simulations for the considered scenarios. The work presented in this paper serves as a basis for the performance evaluation of remaining performance metrics of routing protocols, vital for large scale deployment of ad hoc networks.

  7. 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.

  8. 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

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

    International Nuclear Information System (INIS)

    Serne, R.J.

    1991-10-01

    Recently several articles have been published that question the appropriateness of the distribution coefficient, Rd, concept to quantify radionuclide migration. Several distinct issues are raised by various critics. In this paper I provide some perspective on 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

  10. 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...

  11. Impact of reactive settler models on simulated WWTP performance

    DEFF Research Database (Denmark)

    Gernaey, Krist; Jeppsson, Ulf; Batstone, Damien J.

    2006-01-01

    for an ASM1 case study. Simulations with a whole plant model including the non-reactive Takacs 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 Takacs settler. The second is a fully reactive ASM1 Takacs 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....

  12. 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...

  13. Planetary Suit Hip Bearing Model for Predicting Design vs. Performance

    Science.gov (United States)

    Cowley, Matthew S.; Margerum, Sarah; Harvil, Lauren; Rajulu, Sudhakar

    2011-01-01

    Designing a planetary suit is very complex and often requires difficult trade-offs between performance, cost, mass, and system complexity. In order to verifying that new suit designs meet requirements, full prototypes must eventually be built and tested with human subjects. Using computer models early in the design phase of new hardware development can be advantageous, allowing virtual prototyping to take place. Having easily modifiable models of the suit hard sections may reduce the time it takes to make changes to the hardware designs and then to understand their impact on suit and human performance. A virtual design environment gives designers the ability to think outside the box and exhaust design possibilities before building and testing physical prototypes with human subjects. Reductions in prototyping and testing may eventually reduce development costs. This study is an attempt to develop computer models of the hard components of the suit with known physical characteristics, supplemented with human subject performance data. Objectives: The primary objective was to develop an articulating solid model of the Mark III hip bearings to be used for evaluating suit design performance of the hip joint. Methods: Solid models of a planetary prototype (Mark III) suit s hip bearings and brief section were reverse-engineered from the prototype. The performance of the models was then compared by evaluating the mobility performance differences between the nominal hardware configuration and hardware modifications. This was accomplished by gathering data from specific suited tasks. Subjects performed maximum flexion and abduction tasks while in a nominal suit bearing configuration and in three off-nominal configurations. Performance data for the hip were recorded using state-of-the-art motion capture technology. Results: The results demonstrate that solid models of planetary suit hard segments for use as a performance design tool is feasible. From a general trend perspective

  14. Photovoltaic Reliability Performance Model v 2.0

    Energy Technology Data Exchange (ETDEWEB)

    2016-12-16

    PV-RPM is intended to address more “real world” situations by coupling a photovoltaic system performance model with a reliability model so that inverters, modules, combiner boxes, etc. can experience failures and be repaired (or left unrepaired). The model can also include other effects, such as module output degradation over time or disruptions such as electrical grid outages. In addition, PV-RPM is a dynamic probabilistic model that can be used to run many realizations (i.e., possible future outcomes) of a system’s performance using probability distributions to represent uncertain parameter inputs.

  15. Wind farms providing secondary frequency regulation: evaluating the performance of model-based receding horizon control

    Directory of Open Access Journals (Sweden)

    C. R. Shapiro

    2018-01-01

    Full Text Available This paper is an extended version of our paper presented at the 2016 TORQUE conference (Shapiro et al., 2016. We investigate the use of wind farms to provide secondary frequency regulation for a power grid using a model-based receding horizon control framework. In order to enable real-time implementation, the control actions are computed based on a time-varying one-dimensional wake model. This model describes wake advection and wake interactions, both of which play an important role in wind farm power production. In order to test the control strategy, it is implemented in a large-eddy simulation (LES model of an 84-turbine wind farm using the actuator disk turbine representation. Rotor-averaged velocity measurements at each turbine are used to provide feedback for error correction. The importance of including the dynamics of wake advection in the underlying wake model is tested by comparing the performance of this dynamic-model control approach to a comparable static-model control approach that relies on a modified Jensen model. We compare the performance of both control approaches using two types of regulation signals, RegA and RegD, which are used by PJM, an independent system operator in the eastern United States. The poor performance of the static-model control relative to the dynamic-model control demonstrates that modeling the dynamics of wake advection is key to providing the proposed type of model-based coordinated control of large wind farms. We further explore the performance of the dynamic-model control via composite performance scores used by PJM to qualify plants for regulation services or markets. Our results demonstrate that the dynamic-model-controlled wind farm consistently performs well, passing the qualification threshold for all fast-acting RegD signals. For the RegA signal, which changes over slower timescales, the dynamic-model control leads to average performance that surpasses the qualification threshold, but further

  16. Comparative study of turbulence model performance for axisymmetric sudden expansion flow

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Youngmin; Kim, Young In; Kim, Keung Koo; Yoon, Juhyeon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    In this study, the performance of turbulence models in predicting the turbulent flow in an axisymmetric sudden expansion with an expansion ratio of 4 is assessed for a Reynolds number of 5.6 Χ 10{sup 4}. The comparisons show that the standard k-ε and RSM models provide the best agreement with the experimental data, whereas the standard k-ω model gives poor predictions. Owing to its computational efficiency, the Reynolds Averaged Navier-Stokes (RANS) approach has been widely used for the prediction of turbulent flows and associated pressure losses in a variety of internal flow systems such as a diffuser, orifice, converging nozzle, and pipes with sudden expansion. However, the lack of a general turbulence model often leads to limited applications of a RANS approach, i. e., the accuracy and validity of solutions obtained from RANS equations vary with the turbulence model, flow regime, near-wall treatment, and configuration of the problem. In light of the foregoing, a large amount of turbulence research has been conducted to assess the performance of existing turbulence models for different flow fields. In this paper, the turbulent flow in an axisymmetric sudden expansion is numerically investigated for a Reynolds number of 5.6 Χ 10{sup 4}, with the aim of examining the performance of several turbulence models.

  17. Comparative study of turbulence model performance for axisymmetric sudden expansion flow

    International Nuclear Information System (INIS)

    Bae, Youngmin; Kim, Young In; Kim, Keung Koo; Yoon, Juhyeon

    2013-01-01

    In this study, the performance of turbulence models in predicting the turbulent flow in an axisymmetric sudden expansion with an expansion ratio of 4 is assessed for a Reynolds number of 5.6 Χ 10 4 . The comparisons show that the standard k-ε and RSM models provide the best agreement with the experimental data, whereas the standard k-ω model gives poor predictions. Owing to its computational efficiency, the Reynolds Averaged Navier-Stokes (RANS) approach has been widely used for the prediction of turbulent flows and associated pressure losses in a variety of internal flow systems such as a diffuser, orifice, converging nozzle, and pipes with sudden expansion. However, the lack of a general turbulence model often leads to limited applications of a RANS approach, i. e., the accuracy and validity of solutions obtained from RANS equations vary with the turbulence model, flow regime, near-wall treatment, and configuration of the problem. In light of the foregoing, a large amount of turbulence research has been conducted to assess the performance of existing turbulence models for different flow fields. In this paper, the turbulent flow in an axisymmetric sudden expansion is numerically investigated for a Reynolds number of 5.6 Χ 10 4 , with the aim of examining the performance of several turbulence models

  18. Data modelling and performance of data base systems

    International Nuclear Information System (INIS)

    Rossiter, B.N.

    1984-01-01

    The three main methods of data modelling, hierarchical, network, and relational are described together with their advantages and disadvantages. The hierarchical model has strictly limited applicability, but the other two are of general use, although the network model in many respects defines a storage structure whilst the relational model defines a logical structure. Because of this, network systems are more difficult to use than relational systems but are easier to tune to obtain efficient performance. More advanced models have been developed to capture more semantic detail, and two of these RM/T and the role model are discussed. (orig.)

  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. 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.

  1. Theoretical performance model for single image depth from defocus.

    Science.gov (United States)

    Trouvé-Peloux, Pauline; Champagnat, Frédéric; Le Besnerais, Guy; Idier, Jérôme

    2014-12-01

    In this paper we present a performance model for depth estimation using single image depth from defocus (SIDFD). Our model is based on an original expression of the Cramér-Rao bound (CRB) in this context. We show that this model is consistent with the expected behavior of SIDFD. We then study the influence on the performance of the optical parameters of a conventional camera such as the focal length, the aperture, and the position of the in-focus plane (IFP). We derive an approximate analytical expression of the CRB away from the IFP, and we propose an interpretation of the SIDFD performance in this domain. Finally, we illustrate the predictive capacity of our performance model on experimental data comparing several settings of a consumer camera.

  2. Modeling the Performance of Fast Mulipole Method on HPC platforms

    KAUST Repository

    Ibeid, Huda

    2012-01-01

    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

  3. Integrated Main Propulsion System Performance Reconstruction Process/Models

    Science.gov (United States)

    Lopez, Eduardo; Elliott, Katie; Snell, Steven; Evans, Michael

    2013-01-01

    The Integrated Main Propulsion System (MPS) Performance Reconstruction process provides the MPS post-flight data files needed for postflight reporting to the project integration management and key customers to verify flight performance. This process/model was used as the baseline for the currently ongoing Space Launch System (SLS) work. The process utilizes several methodologies, including multiple software programs, to model integrated propulsion system performance through space shuttle ascent. It is used to evaluate integrated propulsion systems, including propellant tanks, feed systems, rocket engine, and pressurization systems performance throughout ascent based on flight pressure and temperature data. The latest revision incorporates new methods based on main engine power balance model updates to model higher mixture ratio operation at lower engine power levels.

  4. Individualized Next-Generation Biomathematical Modeling of Fatigue and Performance

    National Research Council Canada - National Science Library

    Van Dongen, Hans P

    2006-01-01

    .... This project employed a cutting-edge technique called Bayesian forecasting to develop a novel biomathematical performance model to predict responses to sleep loss and circadian displacement for individual subjects...

  5. Computational Modeling of Human Multiple-Task Performance

    National Research Council Canada - National Science Library

    Kieras, David E; Meyer, David

    2005-01-01

    This is the final report for a project that was a continuation of an earlier, long-term project on the development and validation of the EPIC cognitive architecture for modeling human cognition and performance...

  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. 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...

  8. 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 ...

  9. Rising to the challenge : A model of contest performance

    OpenAIRE

    DesAutels, Philip; Berthon, Pierre; Salehi-Sangari, Esmail

    2011-01-01

    Contests are a ubiquitous form of promotion widely adopted by financial services advertisers, yet, paradoxically, academic research on them is conspicuous in its absence. This work addresses this gap by developing a model of contest engagement and performance. Using motivation theory, factors that drive participant engagement are modeled, and engagement's effect on experience and marketing success of the contest specified. Measures of contest performance, in-contest engagement and post-contes...

  10. A performance model for the communication in fast multipole methods on high-performance computing platforms

    KAUST Repository

    Ibeid, Huda; Yokota, Rio; Keyes, David E.

    2016-01-01

    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

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. A Model of Statistics Performance Based on Achievement Goal Theory.

    Science.gov (United States)

    Bandalos, Deborah L.; Finney, Sara J.; Geske, Jenenne A.

    2003-01-01

    Tests a model of statistics performance based on achievement goal theory. Both learning and performance goals affected achievement indirectly through study strategies, self-efficacy, and test anxiety. Implications of these findings for teaching and learning statistics are discussed. (Contains 47 references, 3 tables, 3 figures, and 1 appendix.)…

  16. 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

  17. 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…

  18. 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.

  19. Enhancing pavement performance prediction models for the Illinois Tollway System

    Directory of Open Access Journals (Sweden)

    Laxmikanth Premkumar

    2016-01-01

    Full Text Available Accurate pavement performance prediction represents an important role in prioritizing future maintenance and rehabilitation needs, and predicting future pavement condition in a pavement management system. The Illinois State Toll Highway Authority (Tollway with over 2000 lane miles of pavement utilizes the condition rating survey (CRS methodology to rate pavement performance. Pavement performance models developed in the past for the Illinois Department of Transportation (IDOT are used by the Tollway to predict the future condition of its network. The model projects future CRS ratings based on pavement type, thickness, traffic, pavement age and current CRS rating. However, with time and inclusion of newer pavement types there was a need to calibrate the existing pavement performance models, as well as, develop models for newer pavement types.This study presents the results of calibrating the existing models, and developing new models for the various pavement types in the Illinois Tollway network. The predicted future condition of the pavements is used in estimating its remaining service life to failure, which is of immediate use in recommending future maintenance and rehabilitation requirements for the network. Keywords: Pavement performance models, Remaining life, Pavement management

  20. 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 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.

  1. How motivation affects academic performance: a structural equation modelling analysis.

    Science.gov (United States)

    Kusurkar, R A; Ten Cate, Th J; Vos, C M P; Westers, P; Croiset, G

    2013-03-01

    Few studies in medical education have studied effect of quality of motivation on performance. Self-Determination Theory based on quality of motivation differentiates between Autonomous Motivation (AM) that originates within an individual and Controlled Motivation (CM) that originates from external sources. To determine whether Relative Autonomous Motivation (RAM, a measure of the balance between AM and CM) affects academic performance through good study strategy and higher study effort and compare this model between subgroups: males and females; students selected via two different systems namely qualitative and weighted lottery selection. Data on motivation, study strategy and effort was collected from 383 medical students of VU University Medical Center Amsterdam and their academic performance results were obtained from the student administration. Structural Equation Modelling analysis technique was used to test a hypothesized model in which high RAM would positively affect Good Study Strategy (GSS) and study effort, which in turn would positively affect academic performance in the form of grade point averages. This model fit well with the data, Chi square = 1.095, df = 3, p = 0.778, RMSEA model fit = 0.000. This model also fitted well for all tested subgroups of students. Differences were found in the strength of relationships between the variables for the different subgroups as expected. In conclusion, RAM positively correlated with academic performance through deep strategy towards study and higher study effort. This model seems valid in medical education in subgroups such as males, females, students selected by qualitative and weighted lottery selection.

  2. Enhancing pavement performance prediction models for the Illinois Tollway System

    OpenAIRE

    Laxmikanth Premkumar; William R. Vavrik

    2016-01-01

    Accurate pavement performance prediction represents an important role in prioritizing future maintenance and rehabilitation needs, and predicting future pavement condition in a pavement management system. The Illinois State Toll Highway Authority (Tollway) with over 2000 lane miles of pavement utilizes the condition rating survey (CRS) methodology to rate pavement performance. Pavement performance models developed in the past for the Illinois Department of Transportation (IDOT) are used by th...

  3. Comparative assessment of PV plant performance models considering climate effects

    DEFF Research Database (Denmark)

    Tina, Giuseppe; Ventura, Cristina; Sera, Dezso

    2017-01-01

    . The methodological approach is based on comparative tests of the analyzed models applied to two PV plants installed respectively in north of Denmark (Aalborg) and in the south of Italy (Agrigento). The different ambient, operating and installation conditions allow to understand how these factors impact the precision...... the performance of the studied PV plants with others, the efficiency of the systems has been estimated by both conventional Performance Ratio and Corrected Performance Ratio...

  4. Performing arts medicine: A research model for South Africa

    Directory of Open Access Journals (Sweden)

    Karendra Devroop

    2014-11-01

    Full Text Available Performing Arts Medicine has developed into a highly specialised field over the past three decades. The Performing Arts Medical Association (PAMA has been the leading proponent of this unique and innovative field with ground-breaking research studies, symposia, conferences and journals dedicated specifically to the medical problems of performing artists. Similar to sports medicine, performing arts medicine caters specifically for the medical problems of performing artists including musicians and dancers. In South Africa there is a tremendous lack of knowledge of the field and unlike our international counterparts, we do not have specialised clinical settings that cater for the medical problems of performing artists. There is also a tremendous lack of research on performance-related medical problems of performing artists in South Africa. Accordingly the purpose of this paper is to present an overview of the field of performing arts medicine, highlight some of the significant findings from recent research studies and present a model for conducting research into the field of performing arts medicine. It is hoped that this research model will lead to increased research on the medical problems of performing artists in South Africa.

  5. 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)

  6. 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

  7. Modelling the Performance of Product Integrated Photovoltaic (PIPV) Cells Indoors

    NARCIS (Netherlands)

    Apostolou, G.; Verwaal, M.; Reinders, Angelina H.M.E.

    2014-01-01

    In this paper we present a model, which have been developed for the estimation of the PV products’ cells’ performance in an indoor environment. The model computes the efficiency and power production of PV technologies, as a function of distance from natural and artificial light sources. It intents

  8. 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)

  9. Identification of human operator performance models utilizing time series analysis

    Science.gov (United States)

    Holden, F. M.; Shinners, S. M.

    1973-01-01

    The results of an effort performed by Sperry Systems Management Division for AMRL in applying time series analysis as a tool for modeling the human operator are presented. This technique is utilized for determining the variation of the human transfer function under various levels of stress. The human operator's model is determined based on actual input and output data from a tracking experiment.

  10. 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…

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

    African Journals Online (AJOL)

    Modeling and Performance Analysis of Manufacturing Systems in Footwear Industry. ... researcher to experiment with different variables and controls the manufacturing process ... In this study Arena simulation software is employed to model and measure ... for Authors · for Policy Makers · about Open Access · Journal Quality.

  13. Modeling the performance of low concentration photovoltaic systems

    Energy Technology Data Exchange (ETDEWEB)

    Reis, F. [SESUL, Faculdade de Ciencias da Universidade de Lisboa, 1749-016 Lisboa (Portugal); WS Energia, Ed. Tecnologia II 47, Taguspark, Oeiras (Portugal); Brito, M.C. [SESUL, Faculdade de Ciencias da Universidade de Lisboa, 1749-016 Lisboa (Portugal); Corregidor, V.; Wemans, J. [WS Energia, Ed. Tecnologia II 47, Taguspark, Oeiras (Portugal); Sorasio, G. [WS Energia, Ed. Tecnologia II 47, Taguspark, Oeiras (Portugal); Centro Richerche ISCAT, VS Pellico, 12037, Saluzzo (Italy)

    2010-07-15

    A theoretical model has been developed to describe the response of V-trough systems in terms of module temperature, power output and energy yield using as inputs the atmospheric conditions. The model was adjusted to DoubleSun {sup registered} concentration technology, which integrates dual-axis tracker and conventional mono-crystalline Si modules. The good agreement between model predictions and the results obtained at WS Energia laboratory, Portugal, validated the model. It is shown that DoubleSun {sup registered} technology increases up to 86% the yearly energy yield of conventional modules relative to a fixed flat-plate system. The model was also used to perform a sensitivity analysis, in order to highlight the relevance of the leading working parameters (such as irradiance) in system performance (energy yield and module temperature). Model results show that the operation module temperature is always below the maximum working temperature defined by the module manufacturers. (author)

  14. Sensitivity and uncertainty analyses for performance assessment modeling

    International Nuclear Information System (INIS)

    Doctor, P.G.

    1988-08-01

    Sensitivity and uncertainty analyses methods for computer models are being applied in performance assessment modeling in the geologic high level radioactive waste repository program. The models used in performance assessment tend to be complex physical/chemical models with large numbers of input variables. There are two basic approaches to sensitivity and uncertainty analyses: deterministic and statistical. The deterministic approach to sensitivity analysis involves numerical calculation or employs the adjoint form of a partial differential equation to compute partial derivatives; the uncertainty analysis is based on Taylor series expansions of the input variables propagated through the model to compute means and variances of the output variable. The statistical approach to sensitivity analysis involves a response surface approximation to the model with the sensitivity coefficients calculated from the response surface parameters; the uncertainty analysis is based on simulation. The methods each have strengths and weaknesses. 44 refs

  15. 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...

  16. Poorly Differentiated Thyroid Carcinoma.

    Science.gov (United States)

    Setia, Namrata; Barletta, Justine A

    2014-12-01

    Poorly differentiated thyroid carcinoma (PDTC) has been recognized for the past 30 years as an entity showing intermediate differentiation and clinical behavior between well-differentiated thyroid carcinomas (ie, papillary thyroid carcinoma and follicular thyroid carcinoma) and anaplastic thyroid carcinoma; however, there has been considerable controversy around the definition of PDTC. In this review, the evolution in the definition of PDTC, current diagnostic criteria, differential diagnoses, potentially helpful immunohistochemical studies, and molecular alterations are discussed with the aim of highlighting where the diagnosis of PDTC currently stands. Published by Elsevier Inc.

  17. Introducing Model Predictive Control for Improving Power Plant Portfolio Performance

    DEFF Research Database (Denmark)

    Edlund, Kristian Skjoldborg; Bendtsen, Jan Dimon; Børresen, Simon

    2008-01-01

    This paper introduces a model predictive control (MPC) approach for construction of a controller for balancing the power generation against consumption in a power system. The objective of the controller is to coordinate a portfolio consisting of multiple power plant units in the effort to perform...... reference tracking and disturbance rejection in an economically optimal way. The performance function is chosen as a mixture of the `1-norm and a linear weighting to model the economics of the system. Simulations show a significant improvement of the performance of the MPC compared to the current...

  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. MODELING SIMULATION AND PERFORMANCE STUDY OF GRIDCONNECTED PHOTOVOLTAIC ENERGY SYSTEM

    OpenAIRE

    Nagendra K; Karthik J; Keerthi Rao C; Kumar Raja Pemmadi

    2017-01-01

    This paper presents Modeling Simulation of grid connected Photovoltaic Energy System and performance study using MATLAB/Simulink. The Photovoltaic energy system is considered in three main parts PV Model, Power conditioning System and Grid interface. The Photovoltaic Model is inter-connected with grid through full scale power electronic devices. The simulation is conducted on the PV energy system at normal temperature and at constant load by using MATLAB.

  20. 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

  1. 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 %.

  2. A Perspective on Computational Human Performance Models as Design Tools

    Science.gov (United States)

    Jones, Patricia M.

    2010-01-01

    The design of interactive systems, including levels of automation, displays, and controls, is usually based on design guidelines and iterative empirical prototyping. A complementary approach is to use computational human performance models to evaluate designs. An integrated strategy of model-based and empirical test and evaluation activities is particularly attractive as a methodology for verification and validation of human-rated systems for commercial space. This talk will review several computational human performance modeling approaches and their applicability to design of display and control requirements.

  3. Two analytical models for evaluating performance of Gigabit Ethernet Hosts

    International Nuclear Information System (INIS)

    Salah, K.

    2006-01-01

    Two analytical models are developed to study the impact of interrupt overhead on operating system performance of network hosts when subjected to Gigabit network traffic. Under heavy network traffic, the system performance will be negatively affected due to interrupt overhead caused by incoming traffic. In particular, excessive latency and significant degradation in system throughput can be experienced. Also user application may livelock as the CPU power is mostly consumed by interrupt handling and protocol processing. In this paper we present and compare two analytical models that capture host behavior and evaluate its performance. The first model is based Markov processes and queuing theory, while the second, which is more accurate but more complex is a pure Markov process. For the most part both models give mathematically-equivalent closed-form solutions for a number of important system performance metrics. These metrics include throughput, latency and stability condition, CPU utilization of interrupt handling and protocol processing and CPU availability for user applications. The analysis yields insight into understanding and predicting the impact of system and network choices on the performance of interrupt-driven systems when subjected to light and heavy network loads. More, importantly, our analytical work can also be valuable in improving host performance. The paper gives guidelines and recommendations to address design and implementation issues. Simulation and reported experimental results show that our analytical models are valid and give a good approximation. (author)

  4. 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.

  5. 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.

  6. 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.

  7. Modelling and measurement of a moving magnet linear compressor performance

    International Nuclear Information System (INIS)

    Liang, Kun; Stone, Richard; Davies, Gareth; Dadd, Mike; Bailey, Paul

    2014-01-01

    A novel moving magnet linear compressor with clearance seals and flexure bearings has been designed and constructed. It is suitable for a refrigeration system with a compact heat exchanger, such as would be needed for CPU cooling. The performance of the compressor has been experimentally evaluated with nitrogen and a mathematical model has been developed to evaluate the performance of the linear compressor. The results from the compressor model and the measurements have been compared in terms of cylinder pressure, the ‘P–V’ loop, stroke, mass flow rate and shaft power. The cylinder pressure was not measured directly but was derived from the compressor dynamics and the motor magnetic force characteristics. The comparisons indicate that the compressor model is well validated and can be used to study the performance of this type of compressor, to help with design optimization and the identification of key parameters affecting the system transients. The electrical and thermodynamic losses were also investigated, particularly for the design point (stroke of 13 mm and pressure ratio of 3.0), since a full understanding of these can lead to an increase in compressor efficiency. - Highlights: • Model predictions of the performance of a novel moving magnet linear compressor. • Prototype linear compressor performance measurements using nitrogen. • Reconstruction of P–V loops using a model of the dynamics and electromagnetics. • Close agreement between the model and measurements for the P–V loops. • The design point motor efficiency was 74%, with potential improvements identified

  8. Charge-coupled-device X-ray detector performance model

    Science.gov (United States)

    Bautz, M. W.; Berman, G. E.; Doty, J. P.; Ricker, G. R.

    1987-01-01

    A model that predicts the performance characteristics of CCD detectors being developed for use in X-ray imaging is presented. The model accounts for the interactions of both X-rays and charged particles with the CCD and simulates the transport and loss of charge in the detector. Predicted performance parameters include detective and net quantum efficiencies, split-event probability, and a parameter characterizing the effective thickness presented by the detector to cosmic-ray protons. The predicted performance of two CCDs of different epitaxial layer thicknesses is compared. The model predicts that in each device incomplete recovery of the charge liberated by a photon of energy between 0.1 and 10 keV is very likely to be accompanied by charge splitting between adjacent pixels. The implications of the model predictions for CCD data processing algorithms are briefly discussed.

  9. 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.

  10. 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

  11. 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.

  12. Performance analysis of NOAA tropospheric signal delay model

    International Nuclear Information System (INIS)

    Ibrahim, Hassan E; El-Rabbany, Ahmed

    2011-01-01

    Tropospheric delay is one of the dominant global positioning system (GPS) errors, which degrades the positioning accuracy. Recent development in tropospheric modeling relies on implementation of more accurate numerical weather prediction (NWP) models. In North America one of the NWP-based tropospheric correction models is the NOAA Tropospheric Signal Delay Model (NOAATrop), which was developed by the US National Oceanic and Atmospheric Administration (NOAA). Because of its potential to improve the GPS positioning accuracy, the NOAATrop model became the focus of many researchers. In this paper, we analyzed the performance of the NOAATrop model and examined its effect on ionosphere-free-based precise point positioning (PPP) solution. We generated 3 year long tropospheric zenith total delay (ZTD) data series for the NOAATrop model, Hopfield model, and the International GNSS Services (IGS) final tropospheric correction product, respectively. These data sets were generated at ten IGS reference stations spanning Canada and the United States. We analyzed the NOAATrop ZTD data series and compared them with those of the Hopfield model. The IGS final tropospheric product was used as a reference. The analysis shows that the performance of the NOAATrop model is a function of both season (time of the year) and geographical location. However, its performance was superior to the Hopfield model in all cases. We further investigated the effect of implementing the NOAATrop model on the ionosphere-free-based PPP solution convergence and accuracy. It is shown that the use of the NOAATrop model improved the PPP solution convergence by 1%, 10% and 15% for the latitude, longitude and height components, respectively

  13. Modeling and prediction of flotation performance using support vector regression

    Directory of Open Access Journals (Sweden)

    Despotović Vladimir

    2017-01-01

    Full Text Available Continuous efforts have been made in recent year to improve the process of paper recycling, as it is of critical importance for saving the wood, water and energy resources. Flotation deinking is considered to be one of the key methods for separation of ink particles from the cellulose fibres. Attempts to model the flotation deinking process have often resulted in complex models that are difficult to implement and use. In this paper a model for prediction of flotation performance based on Support Vector Regression (SVR, is presented. Representative data samples were created in laboratory, under a variety of practical control variables for the flotation deinking process, including different reagents, pH values and flotation residence time. Predictive model was created that was trained on these data samples, and the flotation performance was assessed showing that Support Vector Regression is a promising method even when dataset used for training the model is limited.

  14. 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...... to narrowing the uncertainty and obtaining more robust estimates of future climate change in regions such as Alaska, Greenland, and the broader Arctic....... 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...

  15. Comparison of Simple Versus Performance-Based Fall Prediction Models

    Directory of Open Access Journals (Sweden)

    Shekhar K. Gadkaree BS

    2015-05-01

    Full Text Available Objective: To compare the predictive ability of standard falls prediction models based on physical performance assessments with more parsimonious prediction models based on self-reported data. Design: We developed a series of fall prediction models progressing in complexity and compared area under the receiver operating characteristic curve (AUC across models. Setting: National Health and Aging Trends Study (NHATS, which surveyed a nationally representative sample of Medicare enrollees (age ≥65 at baseline (Round 1: 2011-2012 and 1-year follow-up (Round 2: 2012-2013. Participants: In all, 6,056 community-dwelling individuals participated in Rounds 1 and 2 of NHATS. Measurements: Primary outcomes were 1-year incidence of “ any fall ” and “ recurrent falls .” Prediction models were compared and validated in development and validation sets, respectively. Results: A prediction model that included demographic information, self-reported problems with balance and coordination, and previous fall history was the most parsimonious model that optimized AUC for both any fall (AUC = 0.69, 95% confidence interval [CI] = [0.67, 0.71] and recurrent falls (AUC = 0.77, 95% CI = [0.74, 0.79] in the development set. Physical performance testing provided a marginal additional predictive value. Conclusion: A simple clinical prediction model that does not include physical performance testing could facilitate routine, widespread falls risk screening in the ambulatory care setting.

  16. Investigation into the performance of different models for predicting stutter.

    Science.gov (United States)

    Bright, Jo-Anne; Curran, James M; Buckleton, John S

    2013-07-01

    In this paper we have examined five possible models for the behaviour of the stutter ratio, SR. These were two log-normal models, two gamma models, and a two-component normal mixture model. A two-component normal mixture model was chosen with different behaviours of variance; at each locus SR was described with two distributions, both with the same mean. The distributions have difference variances: one for the majority of the observations and a second for the less well-behaved ones. We apply each model to a set of known single source Identifiler™, NGM SElect™ and PowerPlex(®) 21 DNA profiles to show the applicability of our findings to different data sets. SR determined from the single source profiles were compared to the calculated SR after application of the models. The model performance was tested by calculating the log-likelihoods and comparing the difference in Akaike information criterion (AIC). The two-component normal mixture model systematically outperformed all others, despite the increase in the number of parameters. This model, as well as performing well statistically, has intuitive appeal for forensic biologists and could be implemented in an expert system with a continuous method for DNA interpretation. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  17. Bayesian calibration of power plant models for accurate performance prediction

    International Nuclear Information System (INIS)

    Boksteen, Sowande Z.; Buijtenen, Jos P. van; Pecnik, Rene; Vecht, Dick van der

    2014-01-01

    Highlights: • Bayesian calibration is applied to power plant performance prediction. • Measurements from a plant in operation are used for model calibration. • A gas turbine performance model and steam cycle model are calibrated. • An integrated plant model is derived. • Part load efficiency is accurately predicted as a function of ambient conditions. - Abstract: Gas turbine combined cycles are expected to play an increasingly important role in the balancing of supply and demand in future energy markets. Thermodynamic modeling of these energy systems is frequently applied to assist in decision making processes related to the management of plant operation and maintenance. In most cases, model inputs, parameters and outputs are treated as deterministic quantities and plant operators make decisions with limited or no regard of uncertainties. As the steady integration of wind and solar energy into the energy market induces extra uncertainties, part load operation and reliability are becoming increasingly important. In the current study, methods are proposed to not only quantify various types of uncertainties in measurements and plant model parameters using measured data, but to also assess their effect on various aspects of performance prediction. The authors aim to account for model parameter and measurement uncertainty, and for systematic discrepancy of models with respect to reality. For this purpose, the Bayesian calibration framework of Kennedy and O’Hagan is used, which is especially suitable for high-dimensional industrial problems. The article derives a calibrated model of the plant efficiency as a function of ambient conditions and operational parameters, which is also accurate in part load. The article shows that complete statistical modeling of power plants not only enhances process models, but can also increases confidence in operational decisions

  18. THE USE OF NEURAL NETWORK TECHNOLOGY TO MODEL SWIMMING PERFORMANCE

    Directory of Open Access Journals (Sweden)

    António José Silva

    2007-03-01

    Full Text Available The aims of the present study were: to identify the factors which are able to explain the performance in the 200 meters individual medley and 400 meters front crawl events in young swimmers, to model the performance in those events using non-linear mathematic methods through artificial neural networks (multi-layer perceptrons and to assess the neural network models precision to predict the performance. A sample of 138 young swimmers (65 males and 73 females of national level was submitted to a test battery comprising four different domains: kinanthropometric evaluation, dry land functional evaluation (strength and flexibility, swimming functional evaluation (hydrodynamics, hydrostatic and bioenergetics characteristics and swimming technique evaluation. To establish a profile of the young swimmer non-linear combinations between preponderant variables for each gender and swim performance in the 200 meters medley and 400 meters font crawl events were developed. For this purpose a feed forward neural network was used (Multilayer Perceptron with three neurons in a single hidden layer. The prognosis precision of the model (error lower than 0.8% between true and estimated performances is supported by recent evidence. Therefore, we consider that the neural network tool can be a good approach in the resolution of complex problems such as performance modeling and the talent identification in swimming and, possibly, in a wide variety of sports

  19. 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

  20. The 'poor man's laryngogram'

    International Nuclear Information System (INIS)

    Bartelt, D.

    1991-01-01

    This paper is reassessment of an old method improved by well-directed application of well-known maneuvers of laryngo-pharyngeal function. Although not as visually attractive as a dedicated laryngogram (now hardly ever requested), it does render similarly reliable diagnostic information, which, supported, as occasionally necessary, by conventional tomography, can even surpass that given by the older technique. Its main advantage lies in providing cheap, quick, noninvasive studies with minimal descomfort for the patient. Should further investigation be necessary, for analysis of deep extension, modern cross-sectional imaging methods (especially MR) far surpass even dedicated laryngography in diagnostic value and can be based adequately on 'poor mans's laryngography'. Ways in which this method may be optimised, especially those involving laryngopharyngeal function, are briefly presented - with emphasis on relevant practical aspects - as are normal and abnormal findings. (orig.) [de

  1. 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.

  2. 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

  3. 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.

  4. Proficient brain for optimal performance: the MAP model perspective.

    Science.gov (United States)

    Bertollo, Maurizio; di Fronso, Selenia; Filho, Edson; Conforto, Silvia; Schmid, Maurizio; Bortoli, Laura; Comani, Silvia; Robazza, Claudio

    2016-01-01

    Background. The main goal of the present study was to explore theta and alpha event-related desynchronization/synchronization (ERD/ERS) activity during shooting performance. We adopted the idiosyncratic framework of the multi-action plan (MAP) model to investigate different processing modes underpinning four types of performance. In particular, we were interested in examining the neural activity associated with optimal-automated (Type 1) and optimal-controlled (Type 2) performances. Methods. Ten elite shooters (6 male and 4 female) with extensive international experience participated in the study. ERD/ERS analysis was used to investigate cortical dynamics during performance. A 4 × 3 (performance types × time) repeated measures analysis of variance was performed to test the differences among the four types of performance during the three seconds preceding the shots for theta, low alpha, and high alpha frequency bands. The dependent variables were the ERD/ERS percentages in each frequency band (i.e., theta, low alpha, high alpha) for each electrode site across the scalp. This analysis was conducted on 120 shots for each participant in three different frequency bands and the individual data were then averaged. Results. We found ERS to be mainly associated with optimal-automatic performance, in agreement with the "neural efficiency hypothesis." We also observed more ERD as related to optimal-controlled performance in conditions of "neural adaptability" and proficient use of cortical resources. Discussion. These findings are congruent with the MAP conceptualization of four performance states, in which unique psychophysiological states underlie distinct performance-related experiences. From an applied point of view, our findings suggest that the MAP model can be used as a framework to develop performance enhancement strategies based on cognitive and neurofeedback techniques.

  5. Proficient brain for optimal performance: the MAP model perspective

    Directory of Open Access Journals (Sweden)

    Maurizio Bertollo

    2016-05-01

    Full Text Available Background. The main goal of the present study was to explore theta and alpha event-related desynchronization/synchronization (ERD/ERS activity during shooting performance. We adopted the idiosyncratic framework of the multi-action plan (MAP model to investigate different processing modes underpinning four types of performance. In particular, we were interested in examining the neural activity associated with optimal-automated (Type 1 and optimal-controlled (Type 2 performances. Methods. Ten elite shooters (6 male and 4 female with extensive international experience participated in the study. ERD/ERS analysis was used to investigate cortical dynamics during performance. A 4 × 3 (performance types × time repeated measures analysis of variance was performed to test the differences among the four types of performance during the three seconds preceding the shots for theta, low alpha, and high alpha frequency bands. The dependent variables were the ERD/ERS percentages in each frequency band (i.e., theta, low alpha, high alpha for each electrode site across the scalp. This analysis was conducted on 120 shots for each participant in three different frequency bands and the individual data were then averaged. Results. We found ERS to be mainly associated with optimal-automatic performance, in agreement with the “neural efficiency hypothesis.” We also observed more ERD as related to optimal-controlled performance in conditions of “neural adaptability” and proficient use of cortical resources. Discussion. These findings are congruent with the MAP conceptualization of four performance states, in which unique psychophysiological states underlie distinct performance-related experiences. From an applied point of view, our findings suggest that the MAP model can be used as a framework to develop performance enhancement strategies based on cognitive and neurofeedback techniques.

  6. 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

  7. 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.

  8. Performance verification tests of JT-60SA CS model coil

    Energy Technology Data Exchange (ETDEWEB)

    Obana, Tetsuhiro, E-mail: obana.tetsuhiro@LHD.nifs.ac.jp [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Murakami, Haruyuki [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Takahata, Kazuya; Hamaguchi, Shinji; Chikaraishi, Hirotaka; Mito, Toshiyuki; Imagawa, Shinsaku [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Kizu, Kaname; Natsume, Kyohei; Yoshida, Kiyoshi [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan)

    2015-11-15

    Highlights: • The performance of the JT-60SA CS model coil was verified. • The CS model coil comprised a quad-pancake wound with a Nb{sub 3}Sn CIC conductor. • The CS model coil met the design requirements. - Abstract: As a final check of the coil manufacturing method of the JT-60 Super Advanced (JT-60SA) central solenoid (CS), we verified the performance of a CS model coil. The model coil comprised a quad-pancake wound with a Nb{sub 3}Sn cable-in-conduit conductor. Measurements of the critical current, joint resistance, pressure drop, and magnetic field were conducted in the verification tests. In the critical-current measurement, the critical current of the model coil coincided with the estimation derived from a strain of −0.62% for the Nb{sub 3}Sn strands. As a result, critical-current degradation caused by the coil manufacturing process was not observed. The results of the performance verification tests indicate that the model coil met the design requirements. Consequently, the manufacturing process of the JT-60SA CS was established.

  9. 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

    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......, 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...... and test our research hypotheses. Using a cross-industry sample of 153 innovative firms, we find that corporate foresight can be validly and reliably measured by our measurement instrument. The results of the structural model support the hypothesized positive effects of corporate foresight on all...

  10. A Bibliometric Analysis and Review on Performance Modeling Literature

    Directory of Open Access Journals (Sweden)

    Barbara Livieri

    2015-04-01

    Full Text Available In management practice, performance indicators are considered as a prerequisite to make informed decisions in line with the organization’s goals. On the other hand, indicators summarizes compound phenomena in a few digits, which can induce to inadequate decisions, biased by information loss and conflicting values. Model driven approaches in enterprise engineering can be very effective to avoid these pitfalls, or to take it under control. For that reason, “performance modeling” has the numbers to play a primary role in the “model driven enterprise” scenario, together with process, information and other enterprise-related aspects. In this perspective, we propose a systematic review of the literature on performance modeling in order to retrieve, classify, and summarize existing research, identify the core authors and define areas and opportunities for future research.

  11. 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.

  12. Cassini Radar EQM Model: Instrument Description and Performance Status

    Science.gov (United States)

    Borgarelli, L.; Faustini, E. Zampolini; Im, E.; Johnson, W. T. K.

    1996-01-01

    The spaeccraft of the Cassini Mission is planned to be launched towards Saturn in October 1997. The mission is designed to study the physical structure and chemical composition of Titan. The results of the tests performed on the Cassini radar engineering qualification model (EQM) are summarized. The approach followed in the verification and evaluation of the performance of the radio frequency subsystem EQM is presented. The results show that the instrument satisfies the relevant mission requirements.

  13. Modeling Operator Performance in Low Task Load Supervisory Domains

    Science.gov (United States)

    2011-06-01

    important to model the best and 65 worst performers separately. It is easy to see that the best performers were better multitaskers and more directed...the expected population this research will influence is expected to contain men and women between the ages of 18 and 50 with an interest in using...for your patience and great sense of humor. I could not ask for a better thesis reader. Thank you, Amy D’Agostino, for taking the time to read my

  14. 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 ...

  15. Applying mathematical models to predict resident physician performance and alertness on traditional and novel work schedules.

    Science.gov (United States)

    Klerman, Elizabeth B; Beckett, Scott A; Landrigan, Christopher P

    2016-09-13

    In 2011 the U.S. Accreditation Council for Graduate Medical Education began limiting first year resident physicians (interns) to shifts of ≤16 consecutive hours. Controversy persists regarding the effectiveness of this policy for reducing errors and accidents while promoting education and patient care. Using a mathematical model of the effects of circadian rhythms and length of time awake on objective performance and subjective alertness, we quantitatively compared predictions for traditional intern schedules to those that limit work to ≤ 16 consecutive hours. We simulated two traditional schedules and three novel schedules using the mathematical model. The traditional schedules had extended duration work shifts (≥24 h) with overnight work shifts every second shift (including every third night, Q3) or every third shift (including every fourth night, Q4) night; the novel schedules had two different cross-cover (XC) night team schedules (XC-V1 and XC-V2) and a Rapid Cycle Rotation (RCR) schedule. Predicted objective performance and subjective alertness for each work shift were computed for each individual's schedule within a team and then combined for the team as a whole. Our primary outcome was the amount of time within a work shift during which a team's model-predicted objective performance and subjective alertness were lower than that expected after 16 or 24 h of continuous wake in an otherwise rested individual. The model predicted fewer hours with poor performance and alertness, especially during night-time work hours, for all three novel schedules than for either the traditional Q3 or Q4 schedules. Three proposed schedules that eliminate extended shifts may improve performance and alertness compared with traditional Q3 or Q4 schedules. Predicted times of worse performance and alertness were at night, which is also a time when supervision of trainees is lower. Mathematical modeling provides a quantitative comparison approach with potential to aid

  16. Delay model and performance testing for FPGA carry chain TDC

    International Nuclear Information System (INIS)

    Kang Xiaowen; Liu Yaqiang; Cui Junjian Yang Zhangcan; Jin Yongjie

    2011-01-01

    Time-of-flight (TOF) information would improve the performance of PET (position emission tomography). TDC design is a key technique. It proposed Carry Chain TDC Delay model. Through changing the significant delay parameter of model, paper compared the difference of TDC performance, and finally realized Time-to-Digital Convertor (TDC) based on Carry Chain Method using FPGA EP2C20Q240C8N with 69 ps LSB, max error below 2 LSB. Such result could meet the TOF demand. It also proposed a Coaxial Cable Measuring method for TDC testing, without High-precision test equipment. (authors)

  17. 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).

  18. 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

  19. 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.

  20. Titan I propulsion system modeling and possible performance improvements

    Science.gov (United States)

    Giusti, Oreste

    This thesis features the Titan I propulsion systems and offers data-supported suggestions for improvements to increase performance. The original propulsion systems were modeled both graphically in CAD and via equations. Due to the limited availability of published information, it was necessary to create a more detailed, secondary set of models. Various engineering equations---pertinent to rocket engine design---were implemented in order to generate the desired extra detail. This study describes how these new models were then imported into the ESI CFD Suite. Various parameters are applied to these imported models as inputs that include, for example, bi-propellant combinations, pressure, temperatures, and mass flow rates. The results were then processed with ESI VIEW, which is visualization software. The output files were analyzed for forces in the nozzle, and various results were generated, including sea level thrust and ISP. Experimental data are provided to compare the original engine configuration models to the derivative suggested improvement models.

  1. Software life cycle dynamic simulation model: The organizational performance submodel

    Science.gov (United States)

    Tausworthe, Robert C.

    1985-01-01

    The submodel structure of a software life cycle dynamic simulation model is described. The software process is divided into seven phases, each with product, staff, and funding flows. The model is subdivided into an organizational response submodel, a management submodel, a management influence interface, and a model analyst interface. The concentration here is on the organizational response model, which simulates the performance characteristics of a software development subject to external and internal influences. These influences emanate from two sources: the model analyst interface, which configures the model to simulate the response of an implementing organization subject to its own internal influences, and the management submodel that exerts external dynamic control over the production process. A complete characterization is given of the organizational response submodel in the form of parameterized differential equations governing product, staffing, and funding levels. The parameter values and functions are allocated to the two interfaces.

  2. 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.

  3. Balancing Model Performance and Simplicity to Predict Postoperative Primary Care Blood Pressure Elevation.

    Science.gov (United States)

    Schonberger, Robert B; Dai, Feng; Brandt, Cynthia A; Burg, Matthew M

    2015-09-01

    Because of uncertainty regarding the reliability of perioperative blood pressures and traditional notions downplaying the role of anesthesiologists in longitudinal patient care, there is no consensus for anesthesiologists to recommend postoperative primary care blood pressure follow-up for patients presenting for surgery with an increased blood pressure. The decision of whom to refer should ideally be based on a predictive model that balances performance with ease-of-use. If an acceptable decision rule was developed, a new practice paradigm integrating the surgical encounter into broader public health efforts could be tested, with the goal of reducing long-term morbidity from hypertension among surgical patients. Using national data from US veterans receiving surgical care, we determined the prevalence of poorly controlled outpatient clinic blood pressures ≥140/90 mm Hg, based on the mean of up to 4 readings in the year after surgery. Four increasingly complex logistic regression models were assessed to predict this outcome. The first included the mean of 2 preoperative blood pressure readings; other models progressively added a broad array of demographic and clinical data. After internal validation, the C-statistics and the Net Reclassification Index between the simplest and most complex models were assessed. The performance characteristics of several simple blood pressure referral thresholds were then calculated. Among 215,621 patients, poorly controlled outpatient clinic blood pressure was present postoperatively in 25.7% (95% confidence interval [CI], 25.5%-25.9%) including 14.2% (95% CI, 13.9%-14.6%) of patients lacking a hypertension history. The most complex prediction model demonstrated statistically significant, but clinically marginal, improvement in discrimination over a model based on preoperative blood pressure alone (C-statistic, 0.736 [95% CI, 0.734-0.739] vs 0.721 [95% CI, 0.718-0.723]; P for difference 1 of 4 patients (95% CI, 25

  4. 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....

  5. 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.

  6. Decline Curve Based Models for Predicting Natural Gas Well Performance

    OpenAIRE

    Kamari, Arash; Mohammadi, Amir H.; Lee, Moonyong; Mahmood, Tariq; Bahadori, Alireza

    2016-01-01

    The productivity of a gas well declines over its production life as cannot cover economic policies. To overcome such problems, the production performance of gas wells should be predicted by applying reliable methods to analyse the decline trend. Therefore, reliable models are developed in this study on the basis of powerful artificial intelligence techniques viz. the artificial neural network (ANN) modelling strategy, least square support vector machine (LSSVM) approach, adaptive neuro-fuzzy ...

  7. Health, safety and environmental unit performance assessment model under uncertainty (case study: steel industry).

    Science.gov (United States)

    Shamaii, Azin; Omidvari, Manouchehr; Lotfi, Farhad Hosseinzadeh

    2017-01-01

    Performance assessment is a critical objective of management systems. As a result of the non-deterministic and qualitative nature of performance indicators, assessments are likely to be influenced by evaluators' personal judgments. Furthermore, in developing countries, performance assessments by the Health, Safety and Environment (HSE) department are based solely on the number of accidents. A questionnaire is used to conduct the study in one of the largest steel production companies in Iran. With respect to health, safety, and environment, the results revealed that control of disease, fire hazards, and air pollution are of paramount importance, with coefficients of 0.057, 0.062, and 0.054, respectively. Furthermore, health and environment indicators were found to be the most common causes of poor performance. Finally, it was shown that HSE management systems can affect the majority of performance safety indicators in the short run, whereas health and environment indicators require longer periods of time. The objective of this study is to present an HSE-MS unit performance assessment model in steel industries. Moreover, we seek to answer the following question: what are the factors that affect HSE unit system in the steel industry? Also, for each factor, the extent of impact on the performance of the HSE management system in the organization is determined.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Wavefront control performance modeling with WFIRST shaped pupil coronagraph testbed

    Science.gov (United States)

    Zhou, Hanying; Nemati, Bijian; Krist, John; Cady, Eric; Kern, Brian; Poberezhskiy, Ilya

    2017-09-01

    NASA's WFIRST mission includes a coronagraph instrument (CGI) for direct imaging of exoplanets. Significant improvement in CGI model fidelity has been made recently, alongside a testbed high contrast demonstration in a simulated dynamic environment at JPL. We present our modeling method and results of comparisons to testbed's high order wavefront correction performance for the shaped pupil coronagraph. Agreement between model prediction and testbed result at better than a factor of 2 has been consistently achieved in raw contrast (contrast floor, chromaticity, and convergence), and with that comes good agreement in contrast sensitivity to wavefront perturbations and mask lateral shear.

  13. 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)

  14. 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.

  15. 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…

  16. Influence of horizontal resolution and ensemble size on model performance

    CSIR Research Space (South Africa)

    Dalton, A

    2014-10-01

    Full Text Available Conference of South African Society for Atmospheric Sciences (SASAS), Potchefstroom, 1-2 October 2014 Influence of horizontal resolution and ensemble size on model performance Amaris Dalton*¹, Willem A. Landman ¹ʾ² ¹Departmen of Geography, Geo...

  17. Performance and Cognitive Assessment in 3-D Modeling

    Science.gov (United States)

    Fahrer, Nolan E.; Ernst, Jeremy V.; Branoff, Theodore J.; Clark, Aaron C.

    2011-01-01

    The purpose of this study was to investigate identifiable differences between performance and cognitive assessment scores in a 3-D modeling unit of an engineering drafting course curriculum. The study aimed to provide further investigation of the need of skill-based assessments in engineering/technical graphics courses to potentially increase…

  18. 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 ... Since the .... The investigation hubs are a local brewing company ..... Industrial Engineers, Systems Engineers, Operations ... responsibility the overall management of the new system lies.

  19. INFORMATION SYSTEM FOR MODELING ECONOMIC AND FINANCIAL PERFORMANCES

    Directory of Open Access Journals (Sweden)

    Boldeanu Dana Maria

    2009-05-01

    Full Text Available The analysis of the most important financial and economic indicators at the level of some organizations from the same sector of activity, the selection of performance ratios and generating a particular analysis model help companies to move from the desire

  20. A multilateral modelling of Youth Soccer Performance Index (YSPI)

    Science.gov (United States)

    Bisyri Husin Musawi Maliki, Ahmad; Razali Abdullah, Mohamad; Juahir, Hafizan; Abdullah, Farhana; Ain Shahirah Abdullah, Nurul; Muazu Musa, Rabiu; Musliha Mat-Rasid, Siti; Adnan, Aleesha; Azura Kosni, Norlaila; Muhamad, Wan Siti Amalina Wan; Afiqah Mohamad Nasir, Nur

    2018-04-01

    This study aims to identify the most dominant factors that influencing performance of soccer player and to predict group performance for soccer players. A total of 184 of youth soccer players from Malaysia sport school and six soccer academy encompasses as respondence of the study. Exploratory factor analysis (EFA) and Confirmatory factor analysis (CFA) were computed to identify the most dominant factors whereas reducing the initial 26 parameters with recommended >0.5 of factor loading. Meanwhile, prediction of the soccer performance was predicted by regression model. CFA revealed that sit and reach, vertical jump, VO2max, age, weight, height, sitting height, calf circumference (cc), medial upper arm circumference (muac), maturation, bicep, triceps, subscapular, suprailiac, 5M, 10M, and 20M speed were the most dominant factors. Further index analysis forming Youth Soccer Performance Index (YSPI) resulting by categorizing three groups namely, high, moderate, and low. The regression model for this study was significant set as p < 0.001 and R2 is 0.8222 which explained that the model contributed a total of 82% prediction ability to predict the whole set of the variables. The significant parameters in contributing prediction of YSPI are discussed. As a conclusion, the precision of the prediction models by integrating a multilateral factor reflecting for predicting potential soccer player and hopefully can create a competitive soccer games.