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Sample records for error cleere study

  1. The contributions of near work and outdoor activity to the correlation between siblings in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study.

    Science.gov (United States)

    Jones-Jordan, Lisa A; Sinnott, Loraine T; Graham, Nicholas D; Cotter, Susan A; Kleinstein, Robert N; Manny, Ruth E; Mutti, Donald O; Twelker, J Daniel; Zadnik, Karla

    2014-09-09

    We determined the correlation between sibling refractive errors adjusted for shared and unique environmental factors using data from the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study. Refractive error from subjects' last study visits was used to estimate the intraclass correlation coefficient (ICC) between siblings. The correlation models used environmental factors (diopter-hours and outdoor/sports activity) assessed annually from parents by survey to adjust for shared and unique environmental exposures when estimating the heritability of refractive error (2*ICC). Data from 700 families contributed to the between-sibling correlation for spherical equivalent refractive error. The mean age of the children at the last visit was 13.3 ± 0.90 years. Siblings engaged in similar amounts of near and outdoor activities (correlations ranged from 0.40-0.76). The ICC for spherical equivalent, controlling for age, sex, ethnicity, and site was 0.367 (95% confidence interval [CI] = 0.304, 0.420), with an estimated heritability of no more than 0.733. After controlling for these variables, and near and outdoor/sports activities, the resulting ICC was 0.364 (95% CI = 0.304, 0.420; estimated heritability no more than 0.728, 95% CI = 0.608, 0.850). The ICCs did not differ significantly between male-female and single sex pairs. Adjusting for shared family and unique, child-specific environmental factors only reduced the estimate of refractive error correlation between siblings by 0.5%. Consistent with a lack of association between myopia progression and either near work or outdoor/sports activity, substantial common environmental exposures had little effect on this correlation. Genetic effects appear to have the major role in determining the similarity of refractive error between siblings. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  2. Error studies for SNS Linac. Part 1: Transverse errors

    International Nuclear Information System (INIS)

    Crandall, K.R.

    1998-01-01

    The SNS linac consist of a radio-frequency quadrupole (RFQ), a drift-tube linac (DTL), a coupled-cavity drift-tube linac (CCDTL) and a coupled-cavity linac (CCL). The RFQ and DTL are operated at 402.5 MHz; the CCDTL and CCL are operated at 805 MHz. Between the RFQ and DTL is a medium-energy beam-transport system (MEBT). This error study is concerned with the DTL, CCDTL and CCL, and each will be analyzed separately. In fact, the CCL is divided into two sections, and each of these will be analyzed separately. The types of errors considered here are those that affect the transverse characteristics of the beam. The errors that cause the beam center to be displaced from the linac axis are quad displacements and quad tilts. The errors that cause mismatches are quad gradient errors and quad rotations (roll)

  3. Error studies of Halbach Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, S. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2017-03-02

    These error studies were done on the Halbach magnets for the CBETA “First Girder” as described in note [CBETA001]. The CBETA magnets have since changed slightly to the lattice in [CBETA009]. However, this is not a large enough change to significantly affect the results here. The QF and BD arc FFAG magnets are considered. For each assumed set of error distributions and each ideal magnet, 100 random magnets with errors are generated. These are then run through an automated version of the iron wire multipole cancellation algorithm. The maximum wire diameter allowed is 0.063” as in the proof-of-principle magnets. Initially, 32 wires (2 per Halbach wedge) are tried, then if this does not achieve 1e-­4 level accuracy in the simulation, 48 and then 64 wires. By “1e-4 accuracy”, it is meant the FOM defined by √(Σn≥sextupole an 2+bn 2) is less than 1 unit, where the multipoles are taken at the maximum nominal beam radius, R=23mm for these magnets. The algorithm initially uses 20 convergence interations. If 64 wires does not achieve 1e-­4 accuracy, this is increased to 50 iterations to check for slow converging cases. There are also classifications for magnets that do not achieve 1e-4 but do achieve 1e-3 (FOM ≤ 10 units). This is technically within the spec discussed in the Jan 30, 2017 review; however, there will be errors in practical shimming not dealt with in the simulation, so it is preferable to do much better than the spec in the simulation.

  4. Study of Errors among Nursing Students

    Directory of Open Access Journals (Sweden)

    Ella Koren

    2007-09-01

    Full Text Available The study of errors in the health system today is a topic of considerable interest aimed at reducing errors through analysis of the phenomenon and the conclusions reached. Errors that occur frequently among health professionals have also been observed among nursing students. True, in most cases they are actually “near errors,” but these could be a future indicator of therapeutic reality and the effect of nurses' work environment on their personal performance. There are two different approaches to such errors: (a The EPP (error prone person approach lays full responsibility at the door of the individual involved in the error, whether a student, nurse, doctor, or pharmacist. According to this approach, handling consists purely in identifying and penalizing the guilty party. (b The EPE (error prone environment approach emphasizes the environment as a primary contributory factor to errors. The environment as an abstract concept includes components and processes of interpersonal communications, work relations, human engineering, workload, pressures, technical apparatus, and new technologies. The objective of the present study was to examine the role played by factors in and components of personal performance as compared to elements and features of the environment. The study was based on both of the aforementioned approaches, which, when combined, enable a comprehensive understanding of the phenomenon of errors among the student population as well as a comparison of factors contributing to human error and to error deriving from the environment. The theoretical basis of the study was a model that combined both approaches: one focusing on the individual and his or her personal performance and the other focusing on the work environment. The findings emphasize the work environment of health professionals as an EPE. However, errors could have been avoided by means of strict adherence to practical procedures. The authors examined error events in the

  5. A Comparative Study on Error Analysis

    DEFF Research Database (Denmark)

    Wu, Xiaoli; Zhang, Chun

    2015-01-01

    Title: A Comparative Study on Error Analysis Subtitle: - Belgian (L1) and Danish (L1) learners’ use of Chinese (L2) comparative sentences in written production Xiaoli Wu, Chun Zhang Abstract: Making errors is an inevitable and necessary part of learning. The collection, classification and analysis...... the occurrence of errors either in linguistic or pedagogical terms. The purpose of the current study is to demonstrate the theoretical and practical relevance of error analysis approach in CFL by investigating two cases - (1) Belgian (L1) learners’ use of Chinese (L2) comparative sentences in written production...... of errors in the written and spoken production of L2 learners has a long tradition in L2 pedagogy. Yet, in teaching and learning Chinese as a foreign language (CFL), only handful studies have been made either to define the ‘error’ in a pedagogically insightful way or to empirically investigate...

  6. Study of WATCH GRB error boxes

    DEFF Research Database (Denmark)

    Gorosabel, J.; Castro-Tirado, A. J.; Lund, Niels

    1995-01-01

    We have studied the first WATCH GRB Catalogue ofγ-ray Bursts in order to find correlations between WATCH GRB error boxes and a great variety of celestial objects present in 33 different catalogues. No particular class of objects has been found to be significantly correlated with the WATCH GRBs....

  7. Nursing Errors in Intensive Care Unit by Human Error Identification in Systems Tool: A Case Study

    Directory of Open Access Journals (Sweden)

    Nezamodini

    2016-03-01

    Full Text Available Background Although health services are designed and implemented to improve human health, the errors in health services are a very common phenomenon and even sometimes fatal in this field. Medical errors and their cost are global issues with serious consequences for the patients’ community that are preventable and require serious attention. Objectives The current study aimed to identify possible nursing errors applying human error identification in systems tool (HEIST in the intensive care units (ICUs of hospitals. Patients and Methods This descriptive research was conducted in the intensive care unit of a hospital in Khuzestan province in 2013. Data were collected through observation and interview by nine nurses in this section in a period of four months. Human error classification was based on Rose and Rose and Swain and Guttmann models. According to HEIST work sheets the guide questions were answered and error causes were identified after the determination of the type of errors. Results In total 527 errors were detected. The performing operation on the wrong path had the highest frequency which was 150, and the second rate with a frequency of 136 was doing the tasks later than the deadline. Management causes with a frequency of 451 were the first rank among identified errors. Errors mostly occurred in the system observation stage and among the performance shaping factors (PSFs, time was the most influencing factor in occurrence of human errors. Conclusions Finally, in order to prevent the occurrence and reduce the consequences of identified errors the following suggestions were proposed : appropriate training courses, applying work guidelines and monitoring their implementation, increasing the number of work shifts, hiring professional workforce, equipping work space with appropriate facilities and equipment.

  8. Dissociable genetic contributions to error processing: a multimodal neuroimaging study.

    Directory of Open Access Journals (Sweden)

    Yigal Agam

    Full Text Available Neuroimaging studies reliably identify two markers of error commission: the error-related negativity (ERN, an event-related potential, and functional MRI activation of the dorsal anterior cingulate cortex (dACC. While theorized to reflect the same neural process, recent evidence suggests that the ERN arises from the posterior cingulate cortex not the dACC. Here, we tested the hypothesis that these two error markers also have different genetic mediation.We measured both error markers in a sample of 92 comprised of healthy individuals and those with diagnoses of schizophrenia, obsessive-compulsive disorder or autism spectrum disorder. Participants performed the same task during functional MRI and simultaneously acquired magnetoencephalography and electroencephalography. We examined the mediation of the error markers by two single nucleotide polymorphisms: dopamine D4 receptor (DRD4 C-521T (rs1800955, which has been associated with the ERN and methylenetetrahydrofolate reductase (MTHFR C677T (rs1801133, which has been associated with error-related dACC activation. We then compared the effects of each polymorphism on the two error markers modeled as a bivariate response.We replicated our previous report of a posterior cingulate source of the ERN in healthy participants in the schizophrenia and obsessive-compulsive disorder groups. The effect of genotype on error markers did not differ significantly by diagnostic group. DRD4 C-521T allele load had a significant linear effect on ERN amplitude, but not on dACC activation, and this difference was significant. MTHFR C677T allele load had a significant linear effect on dACC activation but not ERN amplitude, but the difference in effects on the two error markers was not significant.DRD4 C-521T, but not MTHFR C677T, had a significant differential effect on two canonical error markers. Together with the anatomical dissociation between the ERN and error-related dACC activation, these findings suggest that

  9. Students’ Written Production Error Analysis in the EFL Classroom Teaching: A Study of Adult English Learners Errors

    Directory of Open Access Journals (Sweden)

    Ranauli Sihombing

    2016-12-01

    Full Text Available Errors analysis has become one of the most interesting issues in the study of Second Language Acquisition. It can not be denied that some teachers do not know a lot about error analysis and related theories of how L1, L2 or foreign language acquired. In addition, the students often feel upset since they find a gap between themselves and the teachers for the errors the students make and the teachers’ understanding about the error correction. The present research aims to investigate what errors adult English learners make in written production of English. The significances of the study is to know what errors students make in writing that the teachers can find solution to the errors the students make for a better English language teaching and learning especially in teaching English for adults. The study employed qualitative method. The research was undertaken at an airline education center in Bandung. The result showed that syntax errors are more frequently found than morphology errors, especially in terms of verb phrase errors. It is recommended that it is important for teacher to know the theory of second language acquisition in order to know how the students learn and produce theirlanguage. In addition, it will be advantages for teachers if they know what errors students frequently make in their learning, so that the teachers can give solution to the students for a better English language learning achievement.   DOI: https://doi.org/10.24071/llt.2015.180205

  10. Coherent error study in a retarding field energy analyzer

    International Nuclear Information System (INIS)

    Cui, Y.; Zou, Y.; Reiser, M.; Kishek, R.A.; Haber, I.; Bernal, S.; O'Shea, P.G.

    2005-01-01

    A novel cylindrical retarding electrostatic field energy analyzer for low-energy beams has been designed, simulated, and tested with electron beams of several keV, in which space charge effects play an important role. A cylindrical focusing electrode is used to overcome the beam expansion inside the device due to space-charge forces, beam emittance, etc. In this paper, we present the coherent error analysis for this energy analyzer with beam envelope equation including space charge and emittance effects. The study shows that this energy analyzer can achieve very high resolution (with relative error of around 10 -5 ) if taking away the coherent errors by using proper focusing voltages. The theoretical analysis is compared with experimental results

  11. Impact of exposure measurement error in air pollution epidemiology: effect of error type in time-series studies.

    Science.gov (United States)

    Goldman, Gretchen T; Mulholland, James A; Russell, Armistead G; Strickland, Matthew J; Klein, Mitchel; Waller, Lance A; Tolbert, Paige E

    2011-06-22

    Two distinctly different types of measurement error are Berkson and classical. Impacts of measurement error in epidemiologic studies of ambient air pollution are expected to depend on error type. We characterize measurement error due to instrument imprecision and spatial variability as multiplicative (i.e. additive on the log scale) and model it over a range of error types to assess impacts on risk ratio estimates both on a per measurement unit basis and on a per interquartile range (IQR) basis in a time-series study in Atlanta. Daily measures of twelve ambient air pollutants were analyzed: NO2, NOx, O3, SO2, CO, PM10 mass, PM2.5 mass, and PM2.5 components sulfate, nitrate, ammonium, elemental carbon and organic carbon. Semivariogram analysis was applied to assess spatial variability. Error due to this spatial variability was added to a reference pollutant time-series on the log scale using Monte Carlo simulations. Each of these time-series was exponentiated and introduced to a Poisson generalized linear model of cardiovascular disease emergency department visits. Measurement error resulted in reduced statistical significance for the risk ratio estimates for all amounts (corresponding to different pollutants) and types of error. When modelled as classical-type error, risk ratios were attenuated, particularly for primary air pollutants, with average attenuation in risk ratios on a per unit of measurement basis ranging from 18% to 92% and on an IQR basis ranging from 18% to 86%. When modelled as Berkson-type error, risk ratios per unit of measurement were biased away from the null hypothesis by 2% to 31%, whereas risk ratios per IQR were attenuated (i.e. biased toward the null) by 5% to 34%. For CO modelled error amount, a range of error types were simulated and effects on risk ratio bias and significance were observed. For multiplicative error, both the amount and type of measurement error impact health effect estimates in air pollution epidemiology. By modelling

  12. Calculation of track and vertex errors for detector design studies

    International Nuclear Information System (INIS)

    Harr, R.

    1995-01-01

    The Kalman Filter technique has come into wide use for charged track reconstruction in high-energy physics experiments. It is also well suited for detector design studies, allowing for the efficient estimation of optimal track covariance matrices without the need of a hit level Monte Carlo simulation. Although much has been published about the Kalman filter equations, there is a lack of previous literature explaining how to implement the equations. In this paper, the operators necessary to implement the Kalman filter equations for two common detector configurations are worked out: a central detector in a uniform solenoidal magnetic field, and a fixed-target detector with no magnetic field in the region of the interactions. With the track covariance matrices in hand, vertex and invariant mass errors are readily calculable. These quantities are particularly interesting for evaluating experiments designed to study weakly decaying particles which give rise to displaced vertices. The optimal vertex errors are obtained via a constrained vertex fit. Solutions are presented to the constrained vertex problem with and without kinematic constraints. Invariant mass errors are obtained via propagation of errors; the use of vertex constrained track parameters is discussed. Many of the derivations are new or previously unpublished

  13. Sensitivity of dose-finding studies to observation errors.

    Science.gov (United States)

    Zohar, Sarah; O'Quigley, John

    2009-11-01

    The purpose of Phase I designs is to estimate the MTD (maximum tolerated dose, in practice a dose with some given acceptable rate of toxicity) while, at the same time, minimizing the number of patients treated at doses too far removed from the MTD. Our purpose here is to investigate the sensitivity of conclusions from dose-finding designs to recording or observation errors. Certain toxicities may go undetected and, conversely, certain non-toxicities may be incorrectly recorded as dose-limiting toxicities. Recording inaccuracies would be expected to have an influence on final and within trial recommendations and, in this paper, we study in greater depth this question. We focus, in particular on three designs used currently; the standard '3+3' design, the grouped up-and-down design [M. Gezmu, N. Flournoy, Group up-and-down designs for dose finding. Journal of Statistical Planning and Inference 2006; 136 (6): 1749-1764.] and the continual reassessment method (CRM, [J. O'Quigley, M. Pepe, L. Fisher, Continual reassessment method: a practical design for phase 1 clinical trials in cancer. Biometrics 1990; 46 (1): 33-48.]). A non-toxicity incorrectly recorded as a toxicity (error of first kind) has a greater influence in general than the converse (error of second kind). These results are illustrated via figures which suggest that the standard '3+3' design in particular is sensitive to errors of the second kind. Such errors can have a very important impact on drug development in that, if carried through to the Phase 2 and Phase 3 studies, we can significantly increase the probability of failure to detect efficacy as a result of having delivered an inadequate dose.

  14. A Corpus-based Study of EFL Learners’ Errors in IELTS Essay Writing

    OpenAIRE

    Hoda Divsar; Robab Heydari

    2017-01-01

    The present study analyzed different types of errors in the EFL learners’ IELTS essays. In order to determine the major types of errors, a corpus of 70 IELTS examinees’ writings were collected, and their errors were extracted and categorized qualitatively. Errors were categorized based on a researcher-developed error-coding scheme into 13 aspects. Based on the descriptive statistical analyses, the frequency of each error type was calculated and the commonest errors committed by the EFL learne...

  15. Study of systematic errors in the luminosity measurement

    International Nuclear Information System (INIS)

    Arima, Tatsumi

    1993-01-01

    The experimental systematic error in the barrel region was estimated to be 0.44 %. This value is derived considering the systematic uncertainties from the dominant sources but does not include uncertainties which are being studied. In the end cap region, the study of shower behavior and clustering effect is under way in order to determine the angular resolution at the low angle edge of the Liquid Argon Calorimeter. We also expect that the systematic error in this region will be less than 1 %. The technical precision of theoretical uncertainty is better than 0.1 % comparing the Tobimatsu-Shimizu program and BABAMC modified by ALEPH. To estimate the physical uncertainty we will use the ALIBABA [9] which includes O(α 2 ) QED correction in leading-log approximation. (J.P.N.)

  16. Study of systematic errors in the luminosity measurement

    Energy Technology Data Exchange (ETDEWEB)

    Arima, Tatsumi [Tsukuba Univ., Ibaraki (Japan). Inst. of Applied Physics

    1993-04-01

    The experimental systematic error in the barrel region was estimated to be 0.44 %. This value is derived considering the systematic uncertainties from the dominant sources but does not include uncertainties which are being studied. In the end cap region, the study of shower behavior and clustering effect is under way in order to determine the angular resolution at the low angle edge of the Liquid Argon Calorimeter. We also expect that the systematic error in this region will be less than 1 %. The technical precision of theoretical uncertainty is better than 0.1 % comparing the Tobimatsu-Shimizu program and BABAMC modified by ALEPH. To estimate the physical uncertainty we will use the ALIBABA [9] which includes O({alpha}{sup 2}) QED correction in leading-log approximation. (J.P.N.).

  17. Human error in maintenance: An investigative study for the factories of the future

    International Nuclear Information System (INIS)

    Dhillon, B S

    2014-01-01

    This paper presents a study of human error in maintenance. Many different aspects of human error in maintenance considered useful for the factories of the future are studied, including facts, figures, and examples; occurrence of maintenance error in equipment life cycle, elements of a maintenance person's time, maintenance environment and the causes for the occurrence of maintenance error, types and typical maintenance errors, common maintainability design errors and useful design guidelines to reduce equipment maintenance errors, maintenance work instructions, and maintenance error analysis methods

  18. Awareness of Diagnostic Error among Japanese Residents: a Nationwide Study.

    Science.gov (United States)

    Nishizaki, Yuji; Shinozaki, Tomohiro; Kinoshita, Kensuke; Shimizu, Taro; Tokuda, Yasuharu

    2018-04-01

    Residents' understanding of diagnostic error may differ between countries. We sought to explore the relationship between diagnostic error knowledge and self-study, clinical knowledge, and experience. Our nationwide study involved postgraduate year 1 and 2 (PGY-1 and -2) Japanese residents. The Diagnostic Error Knowledge Assessment Test (D-KAT) and General Medicine In-Training Examination (GM-ITE) were administered at the end of the 2014 academic year. D-KAT scores were compared with the benchmark scores of US residents. Associations between D-KAT score and gender, PGY, emergency department (ED) rotations per month, mean number of inpatients handled at any given time, and mean daily minutes of self-study were also analyzed, both with and without adjusting for GM-ITE scores. Student's t test was used for comparisons with linear mixed models and structural equation models (SEM) to explore associations with D-KAT or GM-ITE scores. The mean D-KAT score among Japanese PGY-2 residents was significantly lower than that of their US PGY-2 counterparts (6.2 vs. 8.3, p ITE scores correlated with ED rotations (≥6 rotations: 2.14; 0.16-4.13; p = 0.03), inpatient caseloads (5-9 patients: 1.79; 0.82-2.76; p ITE scores (ß = 0.37, 95% CI: 0.34-0.41) and indirectly associated with ED rotations (ß = 0.06, 95% CI: 0.02-0.10), inpatient caseload (ß = 0.04, 95% CI: 0.003-0.08), and average daily minutes of study (ß = 0.13, 95% CI: 0.09-0.17). Knowledge regarding diagnostic error among Japanese residents was poor compared with that among US residents. D-KAT scores correlated strongly with GM-ITE scores, and the latter scores were positively associated with a greater number of ED rotations, larger caseload (though only up to 15 patients), and more time spent studying.

  19. Learning from Errors: An Exploratory Study Among Dutch Auditors

    NARCIS (Netherlands)

    Gold, A.H.; van Mourik, O.; Van Dyck, Cathy; Wallage, P.

    2017-01-01

    Despite the presence of substantial quality control measures present at audit firms, results from regulator inspections suggest that auditors make errors during their work. According to the error management literature, even though errors often lead to negative immediate consequences, they also offer

  20. Learning from Errors: An Exploratory Study Among Dutch Auditors

    NARCIS (Netherlands)

    Gold, A.H.; Van Dyck, Cathy; Wallage, P.

    Despite the presence of substantial quality control measures present at audit firms, results from regulator inspections suggest that auditors make errors during their work. According to the error management literature, even though errors often lead to negative immediate consequences, they also offer

  1. Learning from Errors: An Exploratory Study Among Dutch Auditors

    NARCIS (Netherlands)

    Gold, A.H.; Van Dyck, Cathy; Wallage, P.

    2016-01-01

    Despite the presence of substantial quality control measures present at audit firms, results from regulator inspections suggest that auditors make errors during their work. According to the error management literature, even though errors often lead to negative immediate consequences, they also offer

  2. Electronic error-reporting systems: a case study into the impact on nurse reporting of medical errors.

    Science.gov (United States)

    Lederman, Reeva; Dreyfus, Suelette; Matchan, Jessica; Knott, Jonathan C; Milton, Simon K

    2013-01-01

    Underreporting of errors in hospitals persists despite the claims of technology companies that electronic systems will facilitate reporting. This study builds on previous analyses to examine error reporting by nurses in hospitals using electronic media. This research asks whether the electronic media creates additional barriers to error reporting, and, if so, what practical steps can all hospitals take to reduce these barriers. This is a mixed-method case study nurses' use of an error reporting system, RiskMan, in two hospitals. The case study involved one large private hospital and one large public hospital in Victoria, Australia, both of which use the RiskMan medical error reporting system. Information technology-based error reporting systems have unique access problems and time demands and can encourage nurses to develop alternative reporting mechanisms. This research focuses on nurses and raises important findings for hospitals using such systems or considering installation. This article suggests organizational and technical responses that could reduce some of the identified barriers. Crown Copyright © 2013. Published by Mosby, Inc. All rights reserved.

  3. Retinal dysfunction and refractive errors: an electrophysiological study of children

    Science.gov (United States)

    Flitcroft, D I; Adams, G G W; Robson, A G; Holder, G E

    2005-01-01

    Aims: To evaluate the relation between refractive error and electrophysiological retinal abnormalities in children referred for investigation of reduced vision. Methods: The study group comprised 123 consecutive patients referred over a 14 month period from the paediatric service of Moorfields Eye Hospital for electrophysiological investigation of reduced vision. Subjects were divided into five refractive categories according to their spectacle correction: high myopia (⩽−6D), low myopia (>−6D and ⩽−0.75D), emmetropia (>−0.75 and 1.5D) and ERG abnormalities (18/35 with high astigmatism v 20/88 without, χ2 test, p = 0.002). There was no significant variation in frequency of abnormalities between low myopes, emmetropes, and low hyperopes. The rate of abnormalities was very similar in both high myopes (8/15) and high hyperopes (5/10). Conclusions: High ametropia and astigmatism in children being investigated for poor vision are associated with a higher rate of retinal electrophysiological abnormalities. An increased rate of refractive errors in the presence of retinal pathology is consistent with the hypothesis that the retina is involved in the process of emmetropisation. Electrophysiological testing should be considered in cases of high ametropia in childhood to rule out associated retinal pathology. PMID:15774929

  4. Aerogel Antennas Communications Study Using Error Vector Magnitude Measurements

    Science.gov (United States)

    Miranda, Felix A.; Mueller, Carl H.; Meador, Mary Ann B.

    2014-01-01

    This presentation discusses an aerogel antennas communication study using error vector magnitude (EVM) measurements. The study was performed using 2x4 element polyimide (PI) aerogel-based phased arrays designed for operation at 5 GHz as transmit (Tx) and receive (Rx) antennas separated by a line of sight (LOS) distance of 8.5 meters. The results of the EVM measurements demonstrate that polyimide aerogel antennas work appropriately to support digital communication links with typically used modulation schemes such as QPSK and 4 DQPSK. As such, PI aerogel antennas with higher gain, larger bandwidth and lower mass than typically used microwave laminates could be suitable to enable aerospace-to- ground communication links with enough channel capacity to support voice, data and video links from CubeSats, unmanned air vehicles (UAV), and commercial aircraft.

  5. Aerogel Antennas Communications Study Using Error Vector Magnitude Measurements

    Science.gov (United States)

    Miranda, Felix A.; Mueller, Carl H.; Meador, Mary Ann B.

    2014-01-01

    This paper discusses an aerogel antennas communication study using error vector magnitude (EVM) measurements. The study was performed using 4x2 element polyimide (PI) aerogel-based phased arrays designed for operation at 5 GHz as transmit (Tx) and receive (Rx) antennas separated by a line of sight (LOS) distance of 8.5 meters. The results of the EVM measurements demonstrate that polyimide aerogel antennas work appropriately to support digital communication links with typically used modulation schemes such as QPSK and pi/4 DQPSK. As such, PI aerogel antennas with higher gain, larger bandwidth and lower mass than typically used microwave laminates could be suitable to enable aerospace-to-ground communication links with enough channel capacity to support voice, data and video links from cubesats, unmanned air vehicles (UAV), and commercial aircraft.

  6. Errors and discrepancies in the administration of intravenous infusions: a mixed methods multihospital observational study

    OpenAIRE

    Lyons, I.; Furniss, D.; Blandford, A.; Chumbley, G.; Iacovides, I.; Wei, L.; Cox, A.; Mayer, A.; Vos, J.; Galal-Edeen, G. H.; Schnock, K. O.; Dykes, P. C.; Bates, D. W.; Franklin, B. D.

    2018-01-01

    INTRODUCTION: Intravenous medication administration has traditionally been regarded as error prone, with high potential for harm. A recent US multisite study revealed few potentially harmful errors despite a high overall error rate. However, there is limited evidence about infusion practices in England and how they relate to prevalence and types of error. OBJECTIVES: To determine the prevalence, types and severity of errors and discrepancies in infusion administration in English hospitals, an...

  7. A dose error evaluation study for 4D dose calculations

    Science.gov (United States)

    Milz, Stefan; Wilkens, Jan J.; Ullrich, Wolfgang

    2014-10-01

    Previous studies have shown that respiration induced motion is not negligible for Stereotactic Body Radiation Therapy. The intrafractional breathing induced motion influences the delivered dose distribution on the underlying patient geometry such as the lung or the abdomen. If a static geometry is used, a planning process for these indications does not represent the entire dynamic process. The quality of a full 4D dose calculation approach depends on the dose coordinate transformation process between deformable geometries. This article provides an evaluation study that introduces an advanced method to verify the quality of numerical dose transformation generated by four different algorithms. The used transformation metric value is based on the deviation of the dose mass histogram (DMH) and the mean dose throughout dose transformation. The study compares the results of four algorithms. In general, two elementary approaches are used: dose mapping and energy transformation. Dose interpolation (DIM) and an advanced concept, so called divergent dose mapping model (dDMM), are used for dose mapping. The algorithms are compared to the basic energy transformation model (bETM) and the energy mass congruent mapping (EMCM). For evaluation 900 small sample regions of interest (ROI) are generated inside an exemplary lung geometry (4DCT). A homogeneous fluence distribution is assumed for dose calculation inside the ROIs. The dose transformations are performed with the four different algorithms. The study investigates the DMH-metric and the mean dose metric for different scenarios (voxel sizes: 8 mm, 4 mm, 2 mm, 1 mm 9 different breathing phases). dDMM achieves the best transformation accuracy in all measured test cases with 3-5% lower errors than the other models. The results of dDMM are reasonable and most efficient in this study, although the model is simple and easy to implement. The EMCM model also achieved suitable results, but the approach requires a more complex

  8. Medication errors in home care: a qualitative focus group study.

    Science.gov (United States)

    Berland, Astrid; Bentsen, Signe Berit

    2017-11-01

    To explore registered nurses' experiences of medication errors and patient safety in home care. The focus of care for older patients has shifted from institutional care towards a model of home care. Medication errors are common in this situation and can result in patient morbidity and mortality. An exploratory qualitative design with focus group interviews was used. Four focus group interviews were conducted with 20 registered nurses in home care. The data were analysed using content analysis. Five categories were identified as follows: lack of information, lack of competence, reporting medication errors, trade name products vs. generic name products, and improving routines. Medication errors occur frequently in home care and can threaten the safety of patients. Insufficient exchange of information and poor communication between the specialist and home-care health services, and between general practitioners and healthcare workers can lead to medication errors. A lack of competence in healthcare workers can also lead to medication errors. To prevent these, it is important that there should be up-to-date information and communication between healthcare workers during the transfer of patients from specialist to home care. Ensuring competence among healthcare workers with regard to medication is also important. In addition, there should be openness and accurate reporting of medication errors, as well as in setting routines for the preparation, alteration and administration of medicines. To prevent medication errors in home care, up-to-date information and communication between healthcare workers is important when patients are transferred from specialist to home care. It is also important to ensure adequate competence with regard to medication, and that there should be openness when medication errors occur, as well as in setting routines for the preparation, alteration and administration of medications. © 2017 John Wiley & Sons Ltd.

  9. Empirical study of the GARCH model with rational errors

    International Nuclear Information System (INIS)

    Chen, Ting Ting; Takaishi, Tetsuya

    2013-01-01

    We use the GARCH model with a fat-tailed error distribution described by a rational function and apply it to stock price data on the Tokyo Stock Exchange. To determine the model parameters we perform Bayesian inference to the model. Bayesian inference is implemented by the Metropolis-Hastings algorithm with an adaptive multi-dimensional Student's t-proposal density. In order to compare our model with the GARCH model with the standard normal errors, we calculate the information criteria AIC and DIC, and find that both criteria favor the GARCH model with a rational error distribution. We also calculate the accuracy of the volatility by using the realized volatility and find that a good accuracy is obtained for the GARCH model with a rational error distribution. Thus we conclude that the GARCH model with a rational error distribution is superior to the GARCH model with the normal errors and it can be used as an alternative GARCH model to those with other fat-tailed distributions

  10. A Corpus-based Study of EFL Learners’ Errors in IELTS Essay Writing

    Directory of Open Access Journals (Sweden)

    Hoda Divsar

    2017-03-01

    Full Text Available The present study analyzed different types of errors in the EFL learners’ IELTS essays. In order to determine the major types of errors, a corpus of 70 IELTS examinees’ writings were collected, and their errors were extracted and categorized qualitatively. Errors were categorized based on a researcher-developed error-coding scheme into 13 aspects. Based on the descriptive statistical analyses, the frequency of each error type was calculated and the commonest errors committed by the EFL learners in IELTS essays were identified. The results indicated that the two most frequent errors that IELTS candidates committed were related to word choice and verb forms. Based on the research results, pedagogical implications highlight analyzing EFL learners’ writing errors as a useful basis for instructional purposes including creating pedagogical teaching materials that are in line with learners’ linguistic strengths and weaknesses.

  11. A comparative study of voluntarily reported medication errors among ...

    African Journals Online (AJOL)

    errors among adult patients in intensive care (IC) and non-. IC settings in Riyadh, ... safety “To err is human: Building a safer health care system” .... regression analysis was used to identify factors affecting the .... that work in non-ICU areas are less likely to report such ... ve.org/read), which permit unrestricted use, distribution ...

  12. GY SAMPLING THEORY IN ENVIRONMENTAL STUDIES 2: SUBSAMPLING ERROR MEASUREMENTS

    Science.gov (United States)

    Sampling can be a significant source of error in the measurement process. The characterization and cleanup of hazardous waste sites require data that meet site-specific levels of acceptable quality if scientifically supportable decisions are to be made. In support of this effort,...

  13. Study of Periodic Fabrication Error of Optical Splitter Device Performance

    OpenAIRE

    Ab-Rahman, Mohammad Syuhaimi; Ater, Foze Saleh; Jumari, Kasmiran; Mohammad, Rahmah

    2012-01-01

    In this paper, the effect of fabrication errors (FEs) on the performance of 1×4 optical power splitter is investigated in details. The FE, which is assumed to take regular shape, is considered in each section of the device. Simulation result show that FE has a significant effect on the output power especially when it occurs in coupling regions.

  14. Human Error Analysis in a Permit to Work System: A Case Study in a Chemical Plant

    Directory of Open Access Journals (Sweden)

    Mehdi Jahangiri

    2016-03-01

    Conclusion: The SPAR-H method applied in this study could analyze and quantify the potential human errors and extract the required measures for reducing the error probabilities in PTW system. Some suggestions to reduce the likelihood of errors, especially in the field of modifying the performance shaping factors and dependencies among tasks are provided.

  15. Numerical study of the systematic error in Monte Carlo schemes for semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Muscato, Orazio [Univ. degli Studi di Catania (Italy). Dipt. di Matematica e Informatica; Di Stefano, Vincenza [Univ. degli Studi di Messina (Italy). Dipt. di Matematica; Wagner, Wolfgang [Weierstrass-Institut fuer Angewandte Analysis und Stochastik (WIAS) im Forschungsverbund Berlin e.V. (Germany)

    2008-07-01

    The paper studies the convergence behavior of Monte Carlo schemes for semiconductors. A detailed analysis of the systematic error with respect to numerical parameters is performed. Different sources of systematic error are pointed out and illustrated in a spatially one-dimensional test case. The error with respect to the number of simulation particles occurs during the calculation of the internal electric field. The time step error, which is related to the splitting of transport and electric field calculations, vanishes sufficiently fast. The error due to the approximation of the trajectories of particles depends on the ODE solver used in the algorithm. It is negligible compared to the other sources of time step error, when a second order Runge-Kutta solver is used. The error related to the approximate scattering mechanism is the most significant source of error with respect to the time step. (orig.)

  16. AN ERROR ANALYSIS OF ARGUMENTATIVE ESSAY (CASE STUDY AT UNIVERSITY MUHAMMADIYAH OF METRO

    Directory of Open Access Journals (Sweden)

    Fenny - Thresia

    2015-10-01

    Full Text Available The purpose of this study was study analyze the students’ error in writing argumentative essay. The researcher focuses on errors of verb, concord and learner language. This study took 20 students as the subject of research from the third semester. The data took from observation and documentation. Based on the result of the data analysis there are some errors still found on the student’s argumentative essay in English writing? The common errors which repeatedly appear are verb. The second is concord, and learner languages are the smallest error. From 20 samples that took, the frequency the errors of verb are 12 items (60%, concord are 8 items (40%, learner languages are 7 items (35%. As a result, verb has the biggest number of common errors.

  17. Factors associated with reporting nursing errors in Iran: a qualitative study

    Directory of Open Access Journals (Sweden)

    Hashemi Fatemeh

    2012-10-01

    Full Text Available Abstract Background Reporting the professional errors for improving patient safety is considered essential not only in hospitals, but also in ambulatory care centers. Unfortunately, a great number of nurses, similar to most clinicians, do not report their errors. Therefore, the present study aimed to clarify the factors associated with reporting the nursing errors through the experiences of clinical nurses and nursing managers. Methods A total of 115 nurses working in the hospitals and specialized clinics affiliated to Tehran and Shiraz Universities of Medical Sciences, Iran participated in this qualitative study. The study data were collected through a semi-structured group discussion conducted in 17 sessions and analyzed by inductive content analysis approach. Results The main categories emerged in this study were: a general approaches of the nurses towards errors, b barriers in reporting the nursing errors, and c motivators in error reporting. Conclusion Error reporting provides extremely valuable information for preventing future errors and improving the patient safety. Overall, regarding motivators and barriers in reporting the nursing errors, it is necessary to enact regulations in which the ways of reporting the error and its constituent elements, such as the notion of the error, are clearly identified.

  18. Medication prescribing errors in a public teaching hospital in India: A prospective study.

    Directory of Open Access Journals (Sweden)

    Pote S

    2007-03-01

    Full Text Available Background: To prevent medication errors in prescribing, one needs to know their types and relative occurrence. Such errors are a great cause of concern as they have the potential to cause patient harm. The aim of this study was to determine the nature and types of medication prescribing errors in an Indian setting.Methods: The medication errors were analyzed in a prospective observational study conducted in 3 medical wards of a public teaching hospital in India. The medication errors were analyzed by means of Micromedex Drug-Reax database.Results: Out of 312 patients, only 304 were included in the study. Of the 304 cases, 103 (34% cases had at least one error. The total number of errors found was 157. The drug-drug interactions were the most frequently (68.2% occurring type of error, which was followed by incorrect dosing interval (12% and dosing errors (9.5%. The medication classes involved most were antimicrobial agents (29.4%, cardiovascular agents (15.4%, GI agents (8.6% and CNS agents (8.2%. The moderate errors contributed maximum (61.8% to the total errors when compared to the major (25.5% and minor (12.7% errors. The results showed that the number of errors increases with age and number of medicines prescribed.Conclusion: The results point to the establishment of medication error reporting at each hospital and to share the data with other hospitals. The role of clinical pharmacist in this situation appears to be a strong intervention; and the clinical pharmacist, initially, could confine to identification of the medication errors.

  19. Errors in translation made by English major students: A study on types and causes

    Directory of Open Access Journals (Sweden)

    Pattanapong Wongranu

    2017-05-01

    Full Text Available Many Thai English major students have problems when they translate Thai texts into English, as numerous errors can be found. Therefore, a study of translation errors is needed to find solutions to these problems. The objectives of this research were: 1 to examine types of translation errors in translation from Thai into English, 2 to determine the types of translation errors that are most common, and 3 to find possible explanations for the causes of errors. The results of this study will be used to improve translation teaching and the course “Translation from Thai into English”. The participants were 26 third-year, English major students at Kasetsart University. The data were collected from the students' exercises and examinations. Interviews and stimulated recall were also used to determine translation problems and causes of errors. The data were analyzed by considering the frequency and percentage, and by content analysis. The results shows that the most frequent translation errors were syntactic errors (65%, followed by semantic errors (26.5% and miscellaneous errors (8.5%, respectively. The causes of errors found in this study included translation procedures, carelessness, low self-confidence, and anxiety. It is recommended that more class time be spent to address the problematic points. In addition, more authentic translation and group work should be implemented to increase self-confidence and decrease anxiety.

  20. Correcting the Standard Errors of 2-Stage Residual Inclusion Estimators for Mendelian Randomization Studies.

    Science.gov (United States)

    Palmer, Tom M; Holmes, Michael V; Keating, Brendan J; Sheehan, Nuala A

    2017-11-01

    Mendelian randomization studies use genotypes as instrumental variables to test for and estimate the causal effects of modifiable risk factors on outcomes. Two-stage residual inclusion (TSRI) estimators have been used when researchers are willing to make parametric assumptions. However, researchers are currently reporting uncorrected or heteroscedasticity-robust standard errors for these estimates. We compared several different forms of the standard error for linear and logistic TSRI estimates in simulations and in real-data examples. Among others, we consider standard errors modified from the approach of Newey (1987), Terza (2016), and bootstrapping. In our simulations Newey, Terza, bootstrap, and corrected 2-stage least squares (in the linear case) standard errors gave the best results in terms of coverage and type I error. In the real-data examples, the Newey standard errors were 0.5% and 2% larger than the unadjusted standard errors for the linear and logistic TSRI estimators, respectively. We show that TSRI estimators with modified standard errors have correct type I error under the null. Researchers should report TSRI estimates with modified standard errors instead of reporting unadjusted or heteroscedasticity-robust standard errors. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health.

  1. Proportion of medication error reporting and associated factors among nurses: a cross sectional study.

    Science.gov (United States)

    Jember, Abebaw; Hailu, Mignote; Messele, Anteneh; Demeke, Tesfaye; Hassen, Mohammed

    2018-01-01

    A medication error (ME) is any preventable event that may cause or lead to inappropriate medication use or patient harm. Voluntary reporting has a principal role in appreciating the extent and impact of medication errors. Thus, exploration of the proportion of medication error reporting and associated factors among nurses is important to inform service providers and program implementers so as to improve the quality of the healthcare services. Institution based quantitative cross-sectional study was conducted among 397 nurses from March 6 to May 10, 2015. Stratified sampling followed by simple random sampling technique was used to select the study participants. The data were collected using structured self-administered questionnaire which was adopted from studies conducted in Australia and Jordan. A pilot study was carried out to validate the questionnaire before data collection for this study. Bivariate and multivariate logistic regression models were fitted to identify factors associated with the proportion of medication error reporting among nurses. An adjusted odds ratio with 95% confidence interval was computed to determine the level of significance. The proportion of medication error reporting among nurses was found to be 57.4%. Regression analysis showed that sex, marital status, having made a medication error and medication error experience were significantly associated with medication error reporting. The proportion of medication error reporting among nurses in this study was found to be higher than other studies.

  2. Study on analysis from sources of error for Airborne LIDAR

    Science.gov (United States)

    Ren, H. C.; Yan, Q.; Liu, Z. J.; Zuo, Z. Q.; Xu, Q. Q.; Li, F. F.; Song, C.

    2016-11-01

    With the advancement of Aerial Photogrammetry, it appears that to obtain geo-spatial information of high spatial and temporal resolution provides a new technical means for Airborne LIDAR measurement techniques, with unique advantages and broad application prospects. Airborne LIDAR is increasingly becoming a new kind of space for earth observation technology, which is mounted by launching platform for aviation, accepting laser pulses to get high-precision, high-density three-dimensional coordinate point cloud data and intensity information. In this paper, we briefly demonstrates Airborne laser radar systems, and that some errors about Airborne LIDAR data sources are analyzed in detail, so the corresponding methods is put forwarded to avoid or eliminate it. Taking into account the practical application of engineering, some recommendations were developed for these designs, which has crucial theoretical and practical significance in Airborne LIDAR data processing fields.

  3. Implementing an error disclosure coaching model: A multicenter case study.

    Science.gov (United States)

    White, Andrew A; Brock, Douglas M; McCotter, Patricia I; Shannon, Sarah E; Gallagher, Thomas H

    2017-01-01

    National guidelines call for health care organizations to provide around-the-clock coaching for medical error disclosure. However, frontline clinicians may not always seek risk managers for coaching. As part of a demonstration project designed to improve patient safety and reduce malpractice liability, we trained multidisciplinary disclosure coaches at 8 health care organizations in Washington State. The training was highly rated by participants, although not all emerged confident in their coaching skill. This multisite intervention can serve as a model for other organizations looking to enhance existing disclosure capabilities. Success likely requires cultural change and repeated practice opportunities for coaches. © 2017 American Society for Healthcare Risk Management of the American Hospital Association.

  4. Error or "act of God"? A study of patients' and operating room team members' perceptions of error definition, reporting, and disclosure.

    Science.gov (United States)

    Espin, Sherry; Levinson, Wendy; Regehr, Glenn; Baker, G Ross; Lingard, Lorelei

    2006-01-01

    Calls abound for a culture change in health care to improve patient safety. However, effective change cannot proceed without a clear understanding of perceptions and beliefs about error. In this study, we describe and compare operative team members' and patients' perceptions of error, reporting of error, and disclosure of error. Thirty-nine interviews of team members (9 surgeons, 9 nurses, 10 anesthesiologists) and patients (11) were conducted at 2 teaching hospitals using 4 scenarios as prompts. Transcribed responses to open questions were analyzed by 2 researchers for recurrent themes using the grounded-theory method. Yes/no answers were compared across groups using chi-square analyses. Team members and patients agreed on what constitutes an error. Deviation from standards and negative outcome were emphasized as definitive features. Patients and nurse professionals differed significantly in their perception of whether errors should be reported. Nurses were willing to report only events within their disciplinary scope of practice. Although most patients strongly advocated full disclosure of errors (what happened and how), team members preferred to disclose only what happened. When patients did support partial disclosure, their rationales varied from that of team members. Both operative teams and patients define error in terms of breaking the rules and the concept of "no harm no foul." These concepts pose challenges for treating errors as system failures. A strong culture of individualism pervades nurses' perception of error reporting, suggesting that interventions are needed to foster collective responsibility and a constructive approach to error identification.

  5. ERROR ANALYSIS IN THE TRAVEL WRITING MADE BY THE STUDENTS OF ENGLISH STUDY PROGRAM

    Directory of Open Access Journals (Sweden)

    Vika Agustina

    2015-05-01

    Full Text Available This study was conducted to identify the kinds of errors in surface strategy taxonomy and to know the dominant type of errors made by the fifth semester students of English Department of one State University in Malang-Indonesia in producing their travel writing. The type of research of this study is document analysis since it analyses written materials, in this case travel writing texts. The analysis finds that the grammatical errors made by the students based on surface strategy taxonomy theory consist of four types. They are (1 omission, (2 addition, (3 misformation and (4 misordering. The most frequent errors occuring in misformation are in the use of tense form. Secondly, the errors are in omission of noun/verb inflection. The next error, there are many clauses that contain unnecessary phrase added there.

  6. The study of error for analysis in dynamic image from the error of count rates in Nal (Tl) scintillation camera

    International Nuclear Information System (INIS)

    Oh, Joo Young; Kang, Chun Goo; Kim, Jung Yul; Oh, Ki Baek; Kim, Jae Sam; Park, Hoon Hee

    2013-01-01

    This study is aimed to evaluate the effect of T 1/2 upon count rates in the analysis of dynamic scan using NaI (Tl) scintillation camera, and suggest a new quality control method with this effects. We producted a point source with '9 9m TcO 4 - of 18.5 to 185 MBq in the 2 mL syringes, and acquired 30 frames of dynamic images with 10 to 60 seconds each using Infinia gamma camera (GE, USA). In the second experiment, 90 frames of dynamic images were acquired from 74 MBq point source by 5 gamma cameras (Infinia 2, Forte 2, Argus 1). There were not significant differences in average count rates of the sources with 18.5 to 92.5 MBq in the analysis of 10 to 60 seconds/frame with 10 seconds interval in the first experiment (p>0.05). But there were significantly low average count rates with the sources over 111 MBq activity at 60 seconds/frame (p<0.01). According to the second analysis results of linear regression by count rates of 5 gamma cameras those were acquired during 90 minutes, counting efficiency of fourth gamma camera was most low as 0.0064%, and gradient and coefficient of variation was high as 0.0042 and 0.229 each. We could not find abnormal fluctuation in χ 2 test with count rates (p>0.02), and we could find the homogeneity of variance in Levene's F-test among the gamma cameras (p>0.05). At the correlation analysis, there was only correlation between counting efficiency and gradient as significant negative correlation (r=-0.90, p<0.05). Lastly, according to the results of calculation of T 1/2 error from change of gradient with -0.25% to +0.25%, if T 1/2 is relatively long, or gradient is high, the error increase relationally. When estimate the value of 4th camera which has highest gradient from the above mentioned result, we could not see T 1/2 error within 60 minutes at that value. In conclusion, it is necessary for the scintillation gamma camera in medical field to manage hard for the quality of radiation measurement. Especially, we found a

  7. A prospective, multicenter study of pharmacist activities resulting in medication error interception in the emergency department.

    Science.gov (United States)

    Patanwala, Asad E; Sanders, Arthur B; Thomas, Michael C; Acquisto, Nicole M; Weant, Kyle A; Baker, Stephanie N; Merritt, Erica M; Erstad, Brian L

    2012-05-01

    The primary objective of this study is to determine the activities of pharmacists that lead to medication error interception in the emergency department (ED). This was a prospective, multicenter cohort study conducted in 4 geographically diverse academic and community EDs in the United States. Each site had clinical pharmacy services. Pharmacists at each site recorded their medication error interceptions for 250 hours of cumulative time when present in the ED (1,000 hours total for all 4 sites). Items recorded included the activities of the pharmacist that led to medication error interception, type of orders, phase of medication use process, and type of error. Independent evaluators reviewed all medication errors. Descriptive analyses were performed for all variables. A total of 16,446 patients presented to the EDs during the study, resulting in 364 confirmed medication error interceptions by pharmacists. The pharmacists' activities that led to medication error interception were as follows: involvement in consultative activities (n=187; 51.4%), review of medication orders (n=127; 34.9%), and other (n=50; 13.7%). The types of orders resulting in medication error interceptions were written or computerized orders (n=198; 54.4%), verbal orders (n=119; 32.7%), and other (n=47; 12.9%). Most medication error interceptions occurred during the prescribing phase of the medication use process (n=300; 82.4%) and the most common type of error was wrong dose (n=161; 44.2%). Pharmacists' review of written or computerized medication orders accounts for only a third of medication error interceptions. Most medication error interceptions occur during consultative activities. Copyright © 2011. Published by Mosby, Inc.

  8. A second study of the prediction of cognitive errors using the 'CREAM' technique

    International Nuclear Information System (INIS)

    Collier, Steve; Andresen, Gisle

    2000-03-01

    Some human errors, such as errors of commission and knowledge-based errors, are not adequately modelled in probabilistic safety assessments. Even qualitative methods for handling these sorts of errors are comparatively underdeveloped. The 'Cognitive Reliability and Error Analysis Method' (CREAM) was recently developed for prediction of cognitive error modes. It has not yet been comprehensively established how reliable, valid and generally useful it could be to researchers and practitioners. A previous study of CREAM at Halden was promising, showing a relationship between errors predicted in advance and those that actually occurred in simulated fault scenarios. The present study continues this work. CREAM was used to make predictions of cognitive error modes throughout two rather difficult fault scenarios. Predictions were made of the most likely cognitive error mode, were one to occur at all, at several points throughout the expected scenarios, based upon the scenario design and description. Each scenario was then run 15 times with different operators. Error modes occurring during simulations were later scored using the task description for the scenario, videotapes of operator actions, eye-track recording, operators' verbal protocols and an expert's concurrent commentary. The scoring team had no previous substantive knowledge of the experiment or the techniques used, so as to provide a more stringent test of the data and knowledge needed for scoring. The scored error modes were then compared with the CREAM predictions to assess the degree of agreement. Some cognitive error modes were predicted successfully, but the results were generally not so encouraging as the previous study. Several problems were found with both the CREAM technique and the data needed to complete the analysis. It was felt that further development was needed before this kind of analysis can be reliable and valid, either in a research setting or as a practitioner's tool in a safety assessment

  9. Error floor behavior study of LDPC codes for concatenated codes design

    Science.gov (United States)

    Chen, Weigang; Yin, Liuguo; Lu, Jianhua

    2007-11-01

    Error floor behavior of low-density parity-check (LDPC) codes using quantized decoding algorithms is statistically studied with experimental results on a hardware evaluation platform. The results present the distribution of the residual errors after decoding failure and reveal that the number of residual error bits in a codeword is usually very small using quantized sum-product (SP) algorithm. Therefore, LDPC code may serve as the inner code in a concatenated coding system with a high code rate outer code and thus an ultra low error floor can be achieved. This conclusion is also verified by the experimental results.

  10. Sensitivity of risk parameters to human errors in reactor safety study for a PWR

    International Nuclear Information System (INIS)

    Samanta, P.K.; Hall, R.E.; Swoboda, A.L.

    1981-01-01

    Sensitivities of the risk parameters, emergency safety system unavailabilities, accident sequence probabilities, release category probabilities and core melt probability were investigated for changes in the human error rates within the general methodological framework of the Reactor Safety Study (RSS) for a Pressurized Water Reactor (PWR). Impact of individual human errors were assessed both in terms of their structural importance to core melt and reliability importance on core melt probability. The Human Error Sensitivity Assessment of a PWR (HESAP) computer code was written for the purpose of this study. The code employed point estimate approach and ignored the smoothing technique applied in RSS. It computed the point estimates for the system unavailabilities from the median values of the component failure rates and proceeded in terms of point values to obtain the point estimates for the accident sequence probabilities, core melt probability, and release category probabilities. The sensitivity measure used was the ratio of the top event probability before and after the perturbation of the constituent events. Core melt probability per reactor year showed significant increase with the increase in the human error rates, but did not show similar decrease with the decrease in the human error rates due to the dominance of the hardware failures. When the Minimum Human Error Rate (M.H.E.R.) used is increased to 10 -3 , the base case human error rates start sensitivity to human errors. This effort now allows the evaluation of new error rate data along with proposed changes in the man machine interface

  11. Prevalence of Refractive Error in Singaporean Chinese Children: The Strabismus, Amblyopia, and Refractive Error in Young Singaporean Children (STARS) Study

    OpenAIRE

    Dirani, Mohamed; Chan, Yiong-Huak; Gazzard, Gus; Hornbeak, Dana Marie; Leo, Seo-Wei; Selvaraj, Prabakaran; Zhou, Brendan; Young, Terri L.; Mitchell, Paul; Varma, Rohit; Wong, Tien Yin; Saw, Seang-Mei

    2010-01-01

    Using population-based data, the authors report, for the first time, the prevalence of refractive error in Singaporean Chinese children aged 6 to 72 months. In selected regions of Singapore, myopia has been shown to affect more than 80% of adults; therefore, this paper provides insights into the development of refractive error at a very young age.

  12. Female residents experiencing medical errors in general internal medicine: a qualitative study.

    Science.gov (United States)

    Mankaka, Cindy Ottiger; Waeber, Gérard; Gachoud, David

    2014-07-10

    Doctors, especially doctors-in-training such as residents, make errors. They have to face the consequences even though today's approach to errors emphasizes systemic factors. Doctors' individual characteristics play a role in how medical errors are experienced and dealt with. The role of gender has previously been examined in a few quantitative studies that have yielded conflicting results. In the present study, we sought to qualitatively explore the experience of female residents with respect to medical errors. In particular, we explored the coping mechanisms displayed after an error. This study took place in the internal medicine department of a Swiss university hospital. Within a phenomenological framework, semi-structured interviews were conducted with eight female residents in general internal medicine. All interviews were audiotaped, fully transcribed, and thereafter analyzed. Seven main themes emerged from the interviews: (1) A perception that there is an insufficient culture of safety and error; (2) The perceived main causes of errors, which included fatigue, work overload, inadequate level of competences in relation to assigned tasks, and dysfunctional communication; (3) Negative feelings in response to errors, which included different forms of psychological distress; (4) Variable attitudes of the hierarchy toward residents involved in an error; (5) Talking about the error, as the core coping mechanism; (6) Defensive and constructive attitudes toward one's own errors; and (7) Gender-specific experiences in relation to errors. Such experiences consisted in (a) perceptions that male residents were more confident and therefore less affected by errors than their female counterparts and (b) perceptions that sexist attitudes among male supervisors can occur and worsen an already painful experience. This study offers an in-depth account of how female residents specifically experience and cope with medical errors. Our interviews with female residents convey the

  13. Operator errors

    International Nuclear Information System (INIS)

    Knuefer; Lindauer

    1980-01-01

    Besides that at spectacular events a combination of component failure and human error is often found. Especially the Rasmussen-Report and the German Risk Assessment Study show for pressurised water reactors that human error must not be underestimated. Although operator errors as a form of human error can never be eliminated entirely, they can be minimized and their effects kept within acceptable limits if a thorough training of personnel is combined with an adequate design of the plant against accidents. Contrary to the investigation of engineering errors, the investigation of human errors has so far been carried out with relatively small budgets. Intensified investigations in this field appear to be a worthwhile effort. (orig.)

  14. [Responsibility due to medication errors in France: a study based on SHAM insurance data].

    Science.gov (United States)

    Theissen, A; Orban, J-C; Fuz, F; Guerin, J-P; Flavin, P; Albertini, S; Maricic, S; Saquet, D; Niccolai, P

    2015-03-01

    The safe medication practices at the hospital constitute a major public health problem. Drug supply chain is a complex process, potentially source of errors and damages for the patient. SHAM insurances are the biggest French provider of medical liability insurances and a relevant source of data on the health care complications. The main objective of the study was to analyze the type and cause of medication errors declared to SHAM and having led to a conviction by a court. We did a retrospective study on insurance claims provided by SHAM insurances with a medication error and leading to a condemnation over a 6-year period (between 2005 and 2010). Thirty-one cases were analysed, 21 for scheduled activity and 10 for emergency activity. Consequences of claims were mostly serious (12 deaths, 14 serious complications, 5 simple complications). The types of medication errors were a drug monitoring error (11 cases), an administration error (5 cases), an overdose (6 cases), an allergy (4 cases), a contraindication (3 cases) and an omission (2 cases). Intravenous route of administration was involved in 19 of 31 cases (61%). The causes identified by the court expert were an error related to service organization (11), an error related to medical practice (11) or nursing practice (13). Only one claim was due to the hospital pharmacy. The claim related to drug supply chain is infrequent but potentially serious. These data should help strengthen quality approach in risk management. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  15. Quantification and handling of sampling errors in instrumental measurements: a case study

    DEFF Research Database (Denmark)

    Andersen, Charlotte Møller; Bro, R.

    2004-01-01

    in certain situations, the effect of systematic errors is also considerable. The relevant errors contributing to the prediction error are: error in instrumental measurements (x-error), error in reference measurements (y-error), error in the estimated calibration model (regression coefficient error) and model...

  16. Neural Bases of Unconscious Error Detection in a Chinese Anagram Solution Task: Evidence from ERP Study.

    Directory of Open Access Journals (Sweden)

    Hua-Zhan Yin

    Full Text Available In everyday life, error monitoring and processing are important for improving ongoing performance in response to a changing environment. However, detecting an error is not always a conscious process. The temporal activation patterns of brain areas related to cognitive control in the absence of conscious awareness of an error remain unknown. In the present study, event-related potentials (ERPs in the brain were used to explore the neural bases of unconscious error detection when subjects solved a Chinese anagram task. Our ERP data showed that the unconscious error detection (UED response elicited a more negative ERP component (N2 than did no error (NE and detect error (DE responses in the 300-400-ms time window, and the DE elicited a greater late positive component (LPC than did the UED and NE in the 900-1200-ms time window after the onset of the anagram stimuli. Taken together with the results of dipole source analysis, the N2 (anterior cingulate cortex might reflect unconscious/automatic conflict monitoring, and the LPC (superior/medial frontal gyrus might reflect conscious error recognition.

  17. Decreasing scoring errors on Wechsler Scale Vocabulary, Comprehension, and Similarities subtests: a preliminary study.

    Science.gov (United States)

    Linger, Michele L; Ray, Glen E; Zachar, Peter; Underhill, Andrea T; LoBello, Steven G

    2007-10-01

    Studies of graduate students learning to administer the Wechsler scales have generally shown that training is not associated with the development of scoring proficiency. Many studies report on the reduction of aggregated administration and scoring errors, a strategy that does not highlight the reduction of errors on subtests identified as most prone to error. This study evaluated the development of scoring proficiency specifically on the Wechsler (WISC-IV and WAIS-III) Vocabulary, Comprehension, and Similarities subtests during training by comparing a set of 'early test administrations' to 'later test administrations.' Twelve graduate students enrolled in an intelligence-testing course participated in the study. Scoring errors (e.g., incorrect point assignment) were evaluated on the students' actual practice administration test protocols. Errors on all three subtests declined significantly when scoring errors on 'early' sets of Wechsler scales were compared to those made on 'later' sets. However, correcting these subtest scoring errors did not cause significant changes in subtest scaled scores. Implications for clinical instruction and future research are discussed.

  18. Assessment of the uncertainty associated with systematic errors in digital instruments: an experimental study on offset errors

    International Nuclear Information System (INIS)

    Attivissimo, F; Giaquinto, N; Savino, M; Cataldo, A

    2012-01-01

    This paper deals with the assessment of the uncertainty due to systematic errors, particularly in A/D conversion-based instruments. The problem of defining and assessing systematic errors is briefly discussed, and the conceptual scheme of gauge repeatability and reproducibility is adopted. A practical example regarding the evaluation of the uncertainty caused by the systematic offset error is presented. The experimental results, obtained under various ambient conditions, show that modelling the variability of systematic errors is more problematic than suggested by the ISO 5725 norm. Additionally, the paper demonstrates the substantial difference between the type B uncertainty evaluation, obtained via the maximum entropy principle applied to manufacturer's specifications, and the type A (experimental) uncertainty evaluation, which reflects actually observable reality. Although it is reasonable to assume a uniform distribution of the offset error, experiments demonstrate that the distribution is not centred and that a correction must be applied. In such a context, this work motivates a more pragmatic and experimental approach to uncertainty, with respect to the directions of supplement 1 of GUM. (paper)

  19. Study of on-machine error identification and compensation methods for micro machine tools

    International Nuclear Information System (INIS)

    Wang, Shih-Ming; Yu, Han-Jen; Lee, Chun-Yi; Chiu, Hung-Sheng

    2016-01-01

    Micro machining plays an important role in the manufacturing of miniature products which are made of various materials with complex 3D shapes and tight machining tolerance. To further improve the accuracy of a micro machining process without increasing the manufacturing cost of a micro machine tool, an effective machining error measurement method and a software-based compensation method are essential. To avoid introducing additional errors caused by the re-installment of the workpiece, the measurement and compensation method should be on-machine conducted. In addition, because the contour of a miniature workpiece machined with a micro machining process is very tiny, the measurement method should be non-contact. By integrating the image re-constructive method, camera pixel correction, coordinate transformation, the error identification algorithm, and trajectory auto-correction method, a vision-based error measurement and compensation method that can on-machine inspect the micro machining errors and automatically generate an error-corrected numerical control (NC) program for error compensation was developed in this study. With the use of the Canny edge detection algorithm and camera pixel calibration, the edges of the contour of a machined workpiece were identified and used to re-construct the actual contour of the work piece. The actual contour was then mapped to the theoretical contour to identify the actual cutting points and compute the machining errors. With the use of a moving matching window and calculation of the similarity between the actual and theoretical contour, the errors between the actual cutting points and theoretical cutting points were calculated and used to correct the NC program. With the use of the error-corrected NC program, the accuracy of a micro machining process can be effectively improved. To prove the feasibility and effectiveness of the proposed methods, micro-milling experiments on a micro machine tool were conducted, and the results

  20. Writing Skill and Categorical Error Analysis: A Study of First Year Undergraduate University Students

    Directory of Open Access Journals (Sweden)

    Adnan Satariyan

    2014-09-01

    Full Text Available Abstract This study identifies and analyses the common errors in writing skill of the first year students of Azad University of South Tehran Branch in relation to their first language (L1, the type of high school they graduated, and their exposure to media and technology in order to learn English. It also determines the categories in which the errors are committed (content, organisation/discourse, vocabulary, mechanics, or syntax and whether or not there is a significant difference in the percentage of errors committed and these categories. Participants of this study are 190 first year students that are asked to write an essay. An error analysis model adapted from Brown (2001 and Gayeta (2002 is then used to evaluate the essay writings in terms of content, organisation, vocabulary, mechanics, and syntax or language use. The results of the study show that the students have greater difficulties in organisation, content, and vocabulary and experience less difficulties in mechanics and syntax.

  1. SIMulation of Medication Error induced by Clinical Trial drug labeling: the SIMME-CT study.

    Science.gov (United States)

    Dollinger, Cecile; Schwiertz, Vérane; Sarfati, Laura; Gourc-Berthod, Chloé; Guédat, Marie-Gabrielle; Alloux, Céline; Vantard, Nicolas; Gauthier, Noémie; He, Sophie; Kiouris, Elena; Caffin, Anne-Gaelle; Bernard, Delphine; Ranchon, Florence; Rioufol, Catherine

    2016-06-01

    To assess the impact of investigational drug labels on the risk of medication error in drug dispensing. A simulation-based learning program focusing on investigational drug dispensing was conducted. The study was undertaken in an Investigational Drugs Dispensing Unit of a University Hospital of Lyon, France. Sixty-three pharmacy workers (pharmacists, residents, technicians or students) were enrolled. Ten risk factors were selected concerning label information or the risk of confusion with another clinical trial. Each risk factor was scored independently out of 5: the higher the score, the greater the risk of error. From 400 labels analyzed, two groups were selected for the dispensing simulation: 27 labels with high risk (score ≥3) and 27 with low risk (score ≤2). Each question in the learning program was displayed as a simulated clinical trial prescription. Medication error was defined as at least one erroneous answer (i.e. error in drug dispensing). For each question, response times were collected. High-risk investigational drug labels correlated with medication error and slower response time. Error rates were significantly 5.5-fold higher for high-risk series. Error frequency was not significantly affected by occupational category or experience in clinical trials. SIMME-CT is the first simulation-based learning tool to focus on investigational drug labels as a risk factor for medication error. SIMME-CT was also used as a training tool for staff involved in clinical research, to develop medication error risk awareness and to validate competence in continuing medical education. © The Author 2016. Published by Oxford University Press in association with the International Society for Quality in Health Care; all rights reserved.

  2. Measuring the relationship between interruptions, multitasking and prescribing errors in an emergency department: a study protocol.

    Science.gov (United States)

    Raban, Magdalena Z; Walter, Scott R; Douglas, Heather E; Strumpman, Dana; Mackenzie, John; Westbrook, Johanna I

    2015-10-13

    Interruptions and multitasking are frequent in clinical settings, and have been shown in the cognitive psychology literature to affect performance, increasing the risk of error. However, comparatively less is known about their impact on errors in clinical work. This study will assess the relationship between prescribing errors, interruptions and multitasking in an emergency department (ED) using direct observations and chart review. The study will be conducted in an ED of a 440-bed teaching hospital in Sydney, Australia. Doctors will be shadowed at proximity by observers for 2 h time intervals while they are working on day shift (between 0800 and 1800). Time stamped data on tasks, interruptions and multitasking will be recorded on a handheld computer using the validated Work Observation Method by Activity Timing (WOMBAT) tool. The prompts leading to interruptions and multitasking will also be recorded. When doctors prescribe medication, type of chart and chart sections written on, along with the patient's medical record number (MRN) will be recorded. A clinical pharmacist will access patient records and assess the medication orders for prescribing errors. The prescribing error rate will be calculated per prescribing task and is defined as the number of errors divided by the number of medication orders written during the prescribing task. The association between prescribing error rates, and rates of prompts, interruptions and multitasking will be assessed using statistical modelling. Ethics approval has been obtained from the hospital research ethics committee. Eligible doctors will be provided with written information sheets and written consent will be obtained if they agree to participate. Doctor details and MRNs will be kept separate from the data on prescribing errors, and will not appear in the final data set for analysis. Study results will be disseminated in publications and feedback to the ED. Published by the BMJ Publishing Group Limited. For permission

  3. Dose variations caused by setup errors in intracranial stereotactic radiotherapy: A PRESAGE study

    International Nuclear Information System (INIS)

    Teng, Kieyin; Gagliardi, Frank; Alqathami, Mamdooh; Ackerly, Trevor; Geso, Moshi

    2014-01-01

    Stereotactic radiotherapy (SRT) requires tight margins around the tumor, thus producing a steep dose gradient between the tumor and the surrounding healthy tissue. Any setup errors might become clinically significant. To date, no study has been performed to evaluate the dosimetric variations caused by setup errors with a 3-dimensional dosimeter, the PRESAGE. This research aimed to evaluate the potential effect that setup errors have on the dose distribution of intracranial SRT. Computed tomography (CT) simulation of a CIRS radiosurgery head phantom was performed with 1.25-mm slice thickness. An ideal treatment plan was generated using Brainlab iPlan. A PRESAGE was made for every treatment with and without errors. A prescan using the optical CT scanner was carried out. Before treatment, the phantom was imaged using Brainlab ExacTrac. Actual radiotherapy treatments with and without errors were carried out with the Novalis treatment machine. Postscan was performed with an optical CT scanner to analyze the dose irradiation. The dose variation between treatments with and without errors was determined using a 3-dimensional gamma analysis. Errors are clinically insignificant when the passing ratio of the gamma analysis is 95% and above. Errors were clinically significant when the setup errors exceeded a 0.7-mm translation and a 0.5° rotation. The results showed that a 3-mm translation shift in the superior-inferior (SI), right-left (RL), and anterior-posterior (AP) directions and 2° couch rotation produced a passing ratio of 53.1%. Translational and rotational errors of 1.5 mm and 1°, respectively, generated a passing ratio of 62.2%. Translation shift of 0.7 mm in the directions of SI, RL, and AP and a 0.5° couch rotation produced a passing ratio of 96.2%. Preventing the occurrences of setup errors in intracranial SRT treatment is extremely important as errors greater than 0.7 mm and 0.5° alter the dose distribution. The geometrical displacements affect dose delivery

  4. Systematic Error Study for ALICE charged-jet v2 Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Heinz, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Soltz, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-07-18

    We study the treatment of systematic errors in the determination of v2 for charged jets in √ sNN = 2:76 TeV Pb-Pb collisions by the ALICE Collaboration. Working with the reported values and errors for the 0-5% centrality data we evaluate the Χ2 according to the formulas given for the statistical and systematic errors, where the latter are separated into correlated and shape contributions. We reproduce both the Χ2 and p-values relative to a null (zero) result. We then re-cast the systematic errors into an equivalent co-variance matrix and obtain identical results, demonstrating that the two methods are equivalent.

  5. Study on Network Error Analysis and Locating based on Integrated Information Decision System

    Science.gov (United States)

    Yang, F.; Dong, Z. H.

    2017-10-01

    Integrated information decision system (IIDS) integrates multiple sub-system developed by many facilities, including almost hundred kinds of software, which provides with various services, such as email, short messages, drawing and sharing. Because the under-layer protocols are different, user standards are not unified, many errors are occurred during the stages of setup, configuration, and operation, which seriously affect the usage. Because the errors are various, which may be happened in different operation phases, stages, TCP/IP communication protocol layers, sub-system software, it is necessary to design a network error analysis and locating tool for IIDS to solve the above problems. This paper studies on network error analysis and locating based on IIDS, which provides strong theory and technology supports for the running and communicating of IIDS.

  6. Effects of Lexico-syntactic Errors on Teaching Materials: A Study of Textbooks Written by Nigerians

    Directory of Open Access Journals (Sweden)

    Peace Chinwendu Israel

    2014-01-01

    Full Text Available This study examined lexico-syntactic errors in selected textbooks written by Nigerians. Our focus was on the educated bilinguals (acrolect who acquired their primary, secondary and tertiary education in Nigeria and the selected textbooks were textbooks published by Vanity Publishers/Press. The participants (authors cut across the three major ethnic groups in Nigeria – Hausa, Igbo and Yoruba and the selection of the textbooks covered the major disciplines of study. We adopted the descriptive research design and specifically employed the survey method to accomplish the purpose of our exploratory research.  The lexico-syntactic errors in the selected textbooks were identified and classified into various categories. These errors were not different from those identified over the years in students’ essays and exam scripts. This buttressed our argument that students are merely the conveyor belt of errors contained in the teaching material and that we can analyse the students’ lexico-syntactic errors in tandem with errors contained in the material used in teaching.

  7. Predictive error detection in pianists: A combined ERP and motion capture study

    Directory of Open Access Journals (Sweden)

    Clemens eMaidhof

    2013-09-01

    Full Text Available Performing a piece of music involves the interplay of several cognitive and motor processes and requires extensive training to achieve a high skill level. However, even professional musicians commit errors occasionally. Previous event-related potential (ERP studies have investigated the neurophysiological correlates of pitch errors during piano performance, and reported pre-error negativity already occurring approximately 70-100 ms before the error had been committed and audible. It was assumed that this pre-error negativity reflects predictive control processes that compare predicted consequences with actual consequences of one’s own actions. However, in previous investigations, correct and incorrect pitch events were confounded by their different tempi. In addition, no data about the underlying movements were available. In the present study, we exploratively recorded the ERPs and 3D movement data of pianists’ fingers simultaneously while they performed fingering exercises from memory. Results showed a pre-error negativity for incorrect keystrokes when both correct and incorrect keystrokes were performed with comparable tempi. Interestingly, even correct notes immediately preceding erroneous keystrokes elicited a very similar negativity. In addition, we explored the possibility of computing ERPs time-locked to a kinematic landmark in the finger motion trajectories defined by when a finger makes initial contact with the key surface, that is, at the onset of tactile feedback. Results suggest that incorrect notes elicited a small difference after the onset of tactile feedback, whereas correct notes preceding incorrect ones elicited negativity before the onset of tactile feedback. The results tentatively suggest that tactile feedback plays an important role in error-monitoring during piano performance, because the comparison between predicted and actual sensory (tactile feedback may provide the information necessary for the detection of an

  8. Prediction-error variance in Bayesian model updating: a comparative study

    Science.gov (United States)

    Asadollahi, Parisa; Li, Jian; Huang, Yong

    2017-04-01

    In Bayesian model updating, the likelihood function is commonly formulated by stochastic embedding in which the maximum information entropy probability model of prediction error variances plays an important role and it is Gaussian distribution subject to the first two moments as constraints. The selection of prediction error variances can be formulated as a model class selection problem, which automatically involves a trade-off between the average data-fit of the model class and the information it extracts from the data. Therefore, it is critical for the robustness in the updating of the structural model especially in the presence of modeling errors. To date, three ways of considering prediction error variances have been seem in the literature: 1) setting constant values empirically, 2) estimating them based on the goodness-of-fit of the measured data, and 3) updating them as uncertain parameters by applying Bayes' Theorem at the model class level. In this paper, the effect of different strategies to deal with the prediction error variances on the model updating performance is investigated explicitly. A six-story shear building model with six uncertain stiffness parameters is employed as an illustrative example. Transitional Markov Chain Monte Carlo is used to draw samples of the posterior probability density function of the structure model parameters as well as the uncertain prediction variances. The different levels of modeling uncertainty and complexity are modeled through three FE models, including a true model, a model with more complexity, and a model with modeling error. Bayesian updating is performed for the three FE models considering the three aforementioned treatments of the prediction error variances. The effect of number of measurements on the model updating performance is also examined in the study. The results are compared based on model class assessment and indicate that updating the prediction error variances as uncertain parameters at the model

  9. Review of human error analysis methodologies and case study for accident management

    International Nuclear Information System (INIS)

    Jung, Won Dae; Kim, Jae Whan; Lee, Yong Hee; Ha, Jae Joo

    1998-03-01

    In this research, we tried to establish the requirements for the development of a new human error analysis method. To achieve this goal, we performed a case study as following steps; 1. review of the existing HEA methods 2. selection of those methods which are considered to be appropriate for the analysis of operator's tasks in NPPs 3. choice of tasks for the application, selected for the case study: HRMS (Human reliability management system), PHECA (Potential Human Error Cause Analysis), CREAM (Cognitive Reliability and Error Analysis Method). And, as the tasks for the application, 'bleed and feed operation' and 'decision-making for the reactor cavity flooding' tasks are chosen. We measured the applicability of the selected methods to the NPP tasks, and evaluated the advantages and disadvantages between each method. The three methods are turned out to be applicable for the prediction of human error. We concluded that both of CREAM and HRMS are equipped with enough applicability for the NPP tasks, however, compared two methods. CREAM is thought to be more appropriate than HRMS from the viewpoint of overall requirements. The requirements for the new HEA method obtained from the study can be summarized as follows; firstly, it should deal with cognitive error analysis, secondly, it should have adequate classification system for the NPP tasks, thirdly, the description on the error causes and error mechanisms should be explicit, fourthly, it should maintain the consistency of the result by minimizing the ambiguity in each step of analysis procedure, fifty, it should be done with acceptable human resources. (author). 25 refs., 30 tabs., 4 figs

  10. The use of adaptive radiation therapy to reduce setup error: a prospective clinical study

    International Nuclear Information System (INIS)

    Yan Di; Wong, John; Vicini, Frank; Robertson, John; Horwitz, Eric; Brabbins, Donald; Cook, Carla; Gustafson, Gary; Stromberg, Jannifer; Martinez, Alvaro

    1996-01-01

    Purpose: Adaptive Radiation Therapy (ART) is a closed-loop feedback process where each patients treatment is adaptively optimized according to the individual variation information measured during the course of treatment. The process aims to maximize the benefits of treatment for the individual patient. A prospective study is currently being conducted to test the feasibility and effectiveness of ART for clinical use. The present study is limited to compensating the effects of systematic setup error. Methods and Materials: The study includes 20 patients treated on a linear accelerator equipped with a computer controlled multileaf collimator (MLC) and a electronic portal imaging device (EPID). Alpha cradles are used to immobilize those patients treated for disease in the thoracic and abdominal regions, and thermal plastic masks for the head and neck. Portal images are acquired daily. Setup error of each treatment field is quantified off-line every day. As determined from an earlier retrospective study of different clinical sites, the measured setup variation from the first 4 to 9 days, are used to estimate systematic setup error and the standard deviation of random setup error for each field. Setup adjustment is made if estimated systematic setup error of the treatment field was larger than or equal to 2 mm. Instead of the conventional approach of repositioning the patient, setup correction is implemented by reshaping MLC to compensate for the estimated systematic error. The entire process from analysis of portal images to the implementation of the modified MLC field is performed via computer network. Systematic and random setup errors of the treatment after adjustment are compared with those prior to adjustment. Finally, the frequency distributions of block overlap cumulated throughout the treatment course are evaluated. Results: Sixty-seven percent of all treatment fields were reshaped to compensate for the estimated systematic errors. At the time of this writing

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

    Science.gov (United States)

    Strobach, Tilo; Schütz, Anja; Schubert, Torsten

    2015-01-01

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

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

    Science.gov (United States)

    Strobach, Tilo; Schütz, Anja; Schubert, Torsten

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Tilo eStrobach

    2015-04-01

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

  14. Perceptions and Attitudes towards Medication Error Reporting in Primary Care Clinics: A Qualitative Study in Malaysia.

    Science.gov (United States)

    Samsiah, A; Othman, Noordin; Jamshed, Shazia; Hassali, Mohamed Azmi

    2016-01-01

    To explore and understand participants' perceptions and attitudes towards the reporting of medication errors (MEs). A qualitative study using in-depth interviews of 31 healthcare practitioners from nine publicly funded, primary care clinics in three states in peninsular Malaysia was conducted for this study. The participants included family medicine specialists, doctors, pharmacists, pharmacist assistants, nurses and assistant medical officers. The interviews were audiotaped and transcribed verbatim. Analysis of the data was guided by the framework approach. Six themes and 28 codes were identified. Despite the availability of a reporting system, most of the participants agreed that MEs were underreported. The nature of the error plays an important role in determining the reporting. The reporting system, organisational factors, provider factors, reporter's burden and benefit of reporting also were identified. Healthcare practitioners in primary care clinics understood the importance of reporting MEs to improve patient safety. Their perceptions and attitudes towards reporting of MEs were influenced by many factors which affect the decision-making process of whether or not to report. Although the process is complex, it primarily is determined by the severity of the outcome of the errors. The participants voluntarily report the errors if they are familiar with the reporting system, what error to report, when to report and what form to use.

  15. Random and correlated errors in gold standards used in nutritional epidemiology: implications for validation studies

    Science.gov (United States)

    The measurement error correction de-attenuation factor was estimated from two studies using recovery biomarkers. One study, the Observing Protein and Energy Nutrition (OPEN), was unable to adequately account for within-person variation in protein and energy intake estimated by recovery biomarkers, ...

  16. A Study of Trial and Error Learning in Technology, Engineering, and Design Education

    Science.gov (United States)

    Franzen, Marissa Marie Sloan

    2016-01-01

    The purpose of this research study was to determine if trial and error learning was an effective, practical, and efficient learning method for Technology, Engineering, and Design Education students at the post-secondary level. A mixed methods explanatory research design was used to measure the viability of the learning source. The study sample was…

  17. A vignette study to examine health care professionals' attitudes towards patient involvement in error prevention.

    Science.gov (United States)

    Schwappach, David L B; Frank, Olga; Davis, Rachel E

    2013-10-01

    Various authorities recommend the participation of patients in promoting patient safety, but little is known about health care professionals' (HCPs') attitudes towards patients' involvement in safety-related behaviours. To investigate how HCPs evaluate patients' behaviours and HCP responses to patient involvement in the behaviour, relative to different aspects of the patient, the involved HCP and the potential error. Cross-sectional fractional factorial survey with seven factors embedded in two error scenarios (missed hand hygiene, medication error). Each survey included two randomized vignettes that described the potential error, a patient's reaction to that error and the HCP response to the patient. Twelve hospitals in Switzerland. A total of 1141 HCPs (response rate 45%). Approval of patients' behaviour, HCP response to the patient, anticipated effects on the patient-HCP relationship, HCPs' support for being asked the question, affective response to the vignettes. Outcomes were measured on 7-point scales. Approval of patients' safety-related interventions was generally high and largely affected by patients' behaviour and correct identification of error. Anticipated effects on the patient-HCP relationship were much less positive, little correlated with approval of patients' behaviour and were mainly determined by the HCP response to intervening patients. HCPs expressed more favourable attitudes towards patients intervening about a medication error than about hand sanitation. This study provides the first insights into predictors of HCPs' attitudes towards patient engagement in safety. Future research is however required to assess the generalizability of the findings into practice before training can be designed to address critical issues. © 2012 John Wiley & Sons Ltd.

  18. Prevalence of refractive errors in the European adult population: the Gutenberg Health Study (GHS).

    Science.gov (United States)

    Wolfram, Christian; Höhn, René; Kottler, Ulrike; Wild, Philipp; Blettner, Maria; Bühren, Jens; Pfeiffer, Norbert; Mirshahi, Alireza

    2014-07-01

    To study the distribution of refractive errors among adults of European descent. Population-based eye study in Germany with 15010 participants aged 35-74 years. The study participants underwent a detailed ophthalmic examination according to a standardised protocol. Refractive error was determined by an automatic refraction device (Humphrey HARK 599) without cycloplegia. Definitions for the analysis were myopia +0.5 D, astigmatism >0.5 cylinder D and anisometropia >1.0 D difference in the spherical equivalent between the eyes. Exclusion criterion was previous cataract or refractive surgery. 13959 subjects were eligible. Refractive errors ranged from -21.5 to +13.88 D. Myopia was present in 35.1% of this study sample, hyperopia in 31.8%, astigmatism in 32.3% and anisometropia in 13.5%. The prevalence of myopia decreased, while the prevalence of hyperopia, astigmatism and anisometropia increased with age. 3.5% of the study sample had no refractive correction for their ametropia. Refractive errors affect the majority of the population. The Gutenberg Health Study sample contains more myopes than other study cohorts in adult populations. Our findings do not support the hypothesis of a generally lower prevalence of myopia among adults in Europe as compared with East Asia.

  19. Medication Errors in an Internal Intensive Care Unit of a Large Teaching Hospital: A Direct Observation Study

    Directory of Open Access Journals (Sweden)

    Saadat Delfani

    2012-06-01

    Full Text Available Medication errors account for about 78% of serious medical errors in intensive care unit (ICU. So far no study has been performed in Iran to evaluate all type of possible medication errors in ICU. Therefore the objective of this study was to reveal the frequency, type and consequences of all type of errors in an ICU of a large teaching hospital. The prospective observational study was conducted in an 11 bed internal ICU of a university hospital in Shiraz. In each shift all processes that were performed on one selected patient was observed and recorded by a trained pharmacist. Observer would intervene only if medication error would cause substantial harm. The data was evaluated and then were entered in a form that was designed for this purpose. The study continued for 38 shifts. During this period, a total of 442 errors per 5785 opportunities for errors (7.6% occurred. Of those, there were 9.8% administration errors, 6.8% prescribing errors, 3.3% transcription errors and, 2.3% dispensing errors. Totally 45 interventions were made, 40% of interventions result in the correction of errors. The most common causes of errors were observed to be: rule violations, slip and memory lapses and lack of drug knowledge. According to our results, the rate of errors is alarming and requires implementation of a serious solution. Since our system lacks a well-organize detection and reporting mechanism, there is no means for preventing errors in the first place. Hence, as the first step we must implement a system where errors are routinely detected and reported.

  20. Abstract probabilistic CNOT gate model based on double encoding: study of the errors and physical realizability

    Science.gov (United States)

    Gueddana, Amor; Attia, Moez; Chatta, Rihab

    2015-03-01

    In this work, we study the error sources standing behind the non-perfect linear optical quantum components composing a non-deterministic quantum CNOT gate model, which performs the CNOT function with a success probability of 4/27 and uses a double encoding technique to represent photonic qubits at the control and the target. We generalize this model to an abstract probabilistic CNOT version and determine the realizability limits depending on a realistic range of the errors. Finally, we discuss physical constraints allowing the implementation of the Asymmetric Partially Polarizing Beam Splitter (APPBS), which is at the heart of correctly realizing the CNOT function.

  1. The causes of prescribing errors in English general practices: a qualitative study.

    Science.gov (United States)

    Slight, Sarah P; Howard, Rachel; Ghaleb, Maisoon; Barber, Nick; Franklin, Bryony Dean; Avery, Anthony J

    2013-10-01

    Few detailed studies exist of the underlying causes of prescribing errors in the UK. To examine the causes of prescribing and monitoring errors in general practice and provide recommendations for how they may be overcome. Qualitative interview and focus group study with purposive sampling of English general practices. General practice staff from 15 general practices across three PCTs in England participated in a combination of semi-structured interviews (n = 34) and six focus groups (n = 46). Thematic analysis informed by Reason's Accident Causation Model was used. Seven categories of high-level error-producing conditions were identified: the prescriber, the patient, the team, the working environment, the task, the computer system, and the primary-secondary care interface. These were broken down to reveal various error-producing conditions: the prescriber's therapeutic training, drug knowledge and experience, knowledge of the patient, perception of risk, and their physical and emotional health; the patient's characteristics and the complexity of the individual clinical case; the importance of feeling comfortable within the practice team was highlighted, as well as the safety implications of GPs signing prescriptions generated by nurses when they had not seen the patient for themselves; the working environment with its extensive workload, time pressures, and interruptions; and computer-related issues associated with mis-selecting drugs from electronic pick-lists and overriding alerts were all highlighted as possible causes of prescribing errors and were often interconnected. Complex underlying causes of prescribing and monitoring errors in general practices were highlighted, several of which are amenable to intervention.

  2. [Medication errors in a hospital emergency department: study of the current situation and critical points for improving patient safety].

    Science.gov (United States)

    Pérez-Díez, Cristina; Real-Campaña, José Manuel; Noya-Castro, María Carmen; Andrés-Paricio, Felicidad; Reyes Abad-Sazatornil, María; Bienvenido Povar-Marco, Javier

    2017-01-01

    To determine the frequency of medication errors and incident types in a tertiary-care hospital emergency department. To quantify and classify medication errors and identify critical points where measures should be implemented to improve patient safety. Prospective direct-observation study to detect errors made in June and July 2016. The overall error rate was 23.7%. The most common errors were made while medications were administered (10.9%). We detected 1532 incidents: 53.6% on workdays (P=.001), 43.1% during the afternoon/evening shift (P=.004), and 43.1% in observation areas (P=.004). The medication error rate was significant. Most errors and incidents occurred during the afternoon/evening shift and in the observation area. Most errors were related to administration of medications.

  3. Correcting for multivariate measurement error by regression calibration in meta-analyses of epidemiological studies.

    NARCIS (Netherlands)

    Kromhout, D.

    2009-01-01

    Within-person variability in measured values of multiple risk factors can bias their associations with disease. The multivariate regression calibration (RC) approach can correct for such measurement error and has been applied to studies in which true values or independent repeat measurements of the

  4. The northern European geoid: a case study on long-wavelength geoid errors

    DEFF Research Database (Denmark)

    Omang, O.C.D.; Forsberg, René

    2002-01-01

    . This method of removing lower-order terms in the Stokes kernel appears to improve the geoid. The best fit to the global positioning system (GPS) leveling points is obtained with a degree of modification of approximately 30. In addition to the study of modification errors, the results of different methods...

  5. Water displacement leg volumetry in clinical studies - A discussion of error sources

    Science.gov (United States)

    2010-01-01

    Background Water displacement leg volumetry is a highly reproducible method, allowing the confirmation of efficacy of vasoactive substances. Nevertheless errors of its execution and the selection of unsuitable patients are likely to negatively affect the outcome of clinical studies in chronic venous insufficiency (CVI). Discussion Placebo controlled double-blind drug studies in CVI were searched (Cochrane Review 2005, MedLine Search until December 2007) and assessed with regard to efficacy (volume reduction of the leg), patient characteristics, and potential methodological error sources. Almost every second study reported only small drug effects (≤ 30 mL volume reduction). As the most relevant error source the conduct of volumetry was identified. Because the practical use of available equipment varies, volume differences of more than 300 mL - which is a multifold of a potential treatment effect - have been reported between consecutive measurements. Other potential error sources were insufficient patient guidance or difficulties with the transition from the Widmer CVI classification to the CEAP (Clinical Etiological Anatomical Pathophysiological) grading. Summary Patients should be properly diagnosed with CVI and selected for stable oedema and further clinical symptoms relevant for the specific study. Centres require a thorough training on the use of the volumeter and on patient guidance. Volumetry should be performed under constant conditions. The reproducibility of short term repeat measurements has to be ensured. PMID:20070899

  6. A prospective three-step intervention study to prevent medication errors in drug handling in paediatric care.

    Science.gov (United States)

    Niemann, Dorothee; Bertsche, Astrid; Meyrath, David; Koepf, Ellen D; Traiser, Carolin; Seebald, Katja; Schmitt, Claus P; Hoffmann, Georg F; Haefeli, Walter E; Bertsche, Thilo

    2015-01-01

    To prevent medication errors in drug handling in a paediatric ward. One in five preventable adverse drug events in hospitalised children is caused by medication errors. Errors in drug prescription have been studied frequently, but data regarding drug handling, including drug preparation and administration, are scarce. A three-step intervention study including monitoring procedure was used to detect and prevent medication errors in drug handling. After approval by the ethics committee, pharmacists monitored drug handling by nurses on an 18-bed paediatric ward in a university hospital prior to and following each intervention step. They also conducted a questionnaire survey aimed at identifying knowledge deficits. Each intervention step targeted different causes of errors. The handout mainly addressed knowledge deficits, the training course addressed errors caused by rule violations and slips, and the reference book addressed knowledge-, memory- and rule-based errors. The number of patients who were subjected to at least one medication error in drug handling decreased from 38/43 (88%) to 25/51 (49%) following the third intervention, and the overall frequency of errors decreased from 527 errors in 581 processes (91%) to 116/441 (26%). The issue of the handout reduced medication errors caused by knowledge deficits regarding, for instance, the correct 'volume of solvent for IV drugs' from 49-25%. Paediatric drug handling is prone to errors. A three-step intervention effectively decreased the high frequency of medication errors by addressing the diversity of their causes. Worldwide, nurses are in charge of drug handling, which constitutes an error-prone but often-neglected step in drug therapy. Detection and prevention of errors in daily routine is necessary for a safe and effective drug therapy. Our three-step intervention reduced errors and is suitable to be tested in other wards and settings. © 2014 John Wiley & Sons Ltd.

  7. Modeling misidentification errors in capture-recapture studies using photographic identification of evolving marks

    Science.gov (United States)

    Yoshizaki, J.; Pollock, K.H.; Brownie, C.; Webster, R.A.

    2009-01-01

    Misidentification of animals is potentially important when naturally existing features (natural tags) are used to identify individual animals in a capture-recapture study. Photographic identification (photoID) typically uses photographic images of animals' naturally existing features as tags (photographic tags) and is subject to two main causes of identification errors: those related to quality of photographs (non-evolving natural tags) and those related to changes in natural marks (evolving natural tags). The conventional methods for analysis of capture-recapture data do not account for identification errors, and to do so requires a detailed understanding of the misidentification mechanism. Focusing on the situation where errors are due to evolving natural tags, we propose a misidentification mechanism and outline a framework for modeling the effect of misidentification in closed population studies. We introduce methods for estimating population size based on this model. Using a simulation study, we show that conventional estimators can seriously overestimate population size when errors due to misidentification are ignored, and that, in comparison, our new estimators have better properties except in cases with low capture probabilities (<0.2) or low misidentification rates (<2.5%). ?? 2009 by the Ecological Society of America.

  8. Correcting for multivariate measurement error by regression calibration in meta-analyses of epidemiological studies

    DEFF Research Database (Denmark)

    Tybjærg-Hansen, Anne

    2009-01-01

    Within-person variability in measured values of multiple risk factors can bias their associations with disease. The multivariate regression calibration (RC) approach can correct for such measurement error and has been applied to studies in which true values or independent repeat measurements...... of the risk factors are observed on a subsample. We extend the multivariate RC techniques to a meta-analysis framework where multiple studies provide independent repeat measurements and information on disease outcome. We consider the cases where some or all studies have repeat measurements, and compare study......-specific, averaged and empirical Bayes estimates of RC parameters. Additionally, we allow for binary covariates (e.g. smoking status) and for uncertainty and time trends in the measurement error corrections. Our methods are illustrated using a subset of individual participant data from prospective long-term studies...

  9. Apology in cases of medical error disclosure: Thoughts based on a preliminary study.

    Science.gov (United States)

    Dahan, Sonia; Ducard, Dominique; Caeymaex, Laurence

    2017-01-01

    Disclosing medical errors is considered necessary by patients, ethicists, and health care professionals. Literature insists on the framing of this disclosure and describes the apology as appropriate and necessary. However, this policy seems difficult to put into practice. Few works have explored the function and meaning of the apology. The aim of this study was to explore the role ascribed to apology in communication between healthcare professionals and patients when disclosing a medical error, and to discuss these findings using a linguistic and philosophical perspective. Qualitative exploratory study, based on face-to-face semi-structured interviews, with seven physicians in a neonatal unit in France. Discourse analysis. Four themes emerged. Difference between apology in everyday life and in the medical encounter; place of the apology in the process of disclosure together with explanations, regrets, empathy and ways to avoid repeating the error; effects of the apology were to allow the patient-physician relationship undermined by the error, to be maintained, responsibility to be accepted, the first steps towards forgiveness to be taken, and a less hierarchical doctor-patient relationship to be created; ways of expressing apology ("I am sorry") reflected regrets and empathy more than an explicit apology. This study highlights how the act of apology can be seen as a "language act" as described by philosophers Austin and Searle, and how it functions as a technique for making amends following a wrongdoing and as an action undertaken in order that neither party should lose face, thus echoing the sociologist Goffmann's interaction theory. This interpretation also accords with the views of Lazare, for whom the function of apology is a restoration of dignity after the humiliation of the error. This approach to the apology illustrates how meaning and impact of real-life language acts can be clarified by philosophical and sociological ideas.

  10. Negative control exposure studies in the presence of measurement error: implications for attempted effect estimate calibration.

    Science.gov (United States)

    Sanderson, Eleanor; Macdonald-Wallis, Corrie; Davey Smith, George

    2018-04-01

    Negative control exposure studies are increasingly being used in epidemiological studies to strengthen causal inference regarding an exposure-outcome association when unobserved confounding is thought to be present. Negative control exposure studies contrast the magnitude of association of the negative control, which has no causal effect on the outcome but is associated with the unmeasured confounders in the same way as the exposure, with the magnitude of the association of the exposure with the outcome. A markedly larger effect of the exposure on the outcome than the negative control on the outcome strengthens inference that the exposure has a causal effect on the outcome. We investigate the effect of measurement error in the exposure and negative control variables on the results obtained from a negative control exposure study. We do this in models with continuous and binary exposure and negative control variables using analysis of the bias of the estimated coefficients and Monte Carlo simulations. Our results show that measurement error in either the exposure or negative control variables can bias the estimated results from the negative control exposure study. Measurement error is common in the variables used in epidemiological studies; these results show that negative control exposure studies cannot be used to precisely determine the size of the effect of the exposure variable, or adequately adjust for unobserved confounding; however, they can be used as part of a body of evidence to aid inference as to whether a causal effect of the exposure on the outcome is present.

  11. Medication knowledge, certainty, and risk of errors in health care: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Johansson Inger

    2011-07-01

    Full Text Available Abstract Background Medication errors are often involved in reported adverse events. Drug therapy, prescribed by physicians, is mostly carried out by nurses, who are expected to master all aspects of medication. Research has revealed the need for improved knowledge in drug dose calculation, and medication knowledge as a whole is poorly investigated. The purpose of this survey was to study registered nurses' medication knowledge, certainty and estimated risk of errors, and to explore factors associated with good results. Methods Nurses from hospitals and primary health care establishments were invited to carry out a multiple-choice test in pharmacology, drug management and drug dose calculations (score range 0-14. Self-estimated certainty in each answer was recorded, graded from 0 = very uncertain to 3 = very certain. Background characteristics and sense of coping were recorded. Risk of error was estimated by combining knowledge and certainty scores. The results are presented as mean (±SD. Results Two-hundred and three registered nurses participated (including 16 males, aged 42.0 (9.3 years with a working experience of 12.4 (9.2 years. Knowledge scores in pharmacology, drug management and drug dose calculations were 10.3 (1.6, 7.5 (1.6, and 11.2 (2.0, respectively, and certainty scores were 1.8 (0.4, 1.9 (0.5, and 2.0 (0.6, respectively. Fifteen percent of the total answers showed a high risk of error, with 25% in drug management. Independent factors associated with high medication knowledge were working in hospitals (p Conclusions Medication knowledge was found to be unsatisfactory among practicing nurses, with a significant risk for medication errors. The study revealed a need to improve the nurses' basic knowledge, especially when referring to drug management.

  12. Organizational Climate, Stress, and Error in Primary Care: The MEMO Study

    Science.gov (United States)

    2005-05-01

    quality, and errors. This model was derived from our earlier work, the Physician Worklife Study14,15 as well as the pioneering work of Lazarus and... Worklife Study instrument,14, 15 and included our five-item global job satisfaction measure and a newly implemented four-item job stress measure.21...measures of practice emphasis with respect to issues such as work–home balance , professionalism, and diversity in office staff, as well as single

  13. Visual acuity measures do not reliably detect childhood refractive error--an epidemiological study.

    Directory of Open Access Journals (Sweden)

    Lisa O'Donoghue

    Full Text Available PURPOSE: To investigate the utility of uncorrected visual acuity measures in screening for refractive error in white school children aged 6-7-years and 12-13-years. METHODS: The Northern Ireland Childhood Errors of Refraction (NICER study used a stratified random cluster design to recruit children from schools in Northern Ireland. Detailed eye examinations included assessment of logMAR visual acuity and cycloplegic autorefraction. Spherical equivalent refractive data from the right eye were used to classify significant refractive error as myopia of at least 1DS, hyperopia as greater than +3.50DS and astigmatism as greater than 1.50DC, whether it occurred in isolation or in association with myopia or hyperopia. RESULTS: Results are presented from 661 white 12-13-year-old and 392 white 6-7-year-old school-children. Using a cut-off of uncorrected visual acuity poorer than 0.20 logMAR to detect significant refractive error gave a sensitivity of 50% and specificity of 92% in 6-7-year-olds and 73% and 93% respectively in 12-13-year-olds. In 12-13-year-old children a cut-off of poorer than 0.20 logMAR had a sensitivity of 92% and a specificity of 91% in detecting myopia and a sensitivity of 41% and a specificity of 84% in detecting hyperopia. CONCLUSIONS: Vision screening using logMAR acuity can reliably detect myopia, but not hyperopia or astigmatism in school-age children. Providers of vision screening programs should be cognisant that where detection of uncorrected hyperopic and/or astigmatic refractive error is an aspiration, current UK protocols will not effectively deliver.

  14. A simulation study on the variation of virtual NMR signals by winding, bobbin, spacer error of HTS magnet

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jun Seong; Lee, Woo Seung; Kim, Jin Sub; Song, Seung Hyun; Nam, Seok Ho; Jeon, Hae Ryong; Beak, Geon Woo; Ko, Tae Kuk [Yonsei University, Seoul (Korea, Republic of)

    2016-09-15

    Recently, production technique and property of the High-Temperature Superconductor (HTS) tape have been improved. Thus, the study on applying an HTS magnet to the high magnetic field application is rapidly increased. A Nuclear Magnetic Resonance (NMR) spectrometer requires high magnitude and homogeneous of central magnetic field. However, the HTS magnet has fabrication errors because shape of HTS is tape and HTS magnet is manufactured by winding HTS tape to the bobbin. The fabrication errors are winding error, bobbin diameter error, spacer thickness error and so on. The winding error occurs when HTS tape is departed from the arranged position on the bobbin. The bobbin diameter and spacer thickness error occur since the diameter of bobbin and spacer are inaccurate. These errors lead magnitude and homogeneity of central magnetic field to be different from its ideal design. The purpose of this paper is to investigate the effect of winding error, bobbin diameter error and spacer thickness error on the central field and field homogeneity of HTS magnet using the virtual NMR signals in MATLAB simulation.

  15. Study of run time errors of the ATLAS Pixel Detector in the 2012 data taking period

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00339072

    2013-05-16

    The high resolution silicon Pixel detector is critical in event vertex reconstruction and in particle track reconstruction in the ATLAS detector. During the pixel data taking operation, some modules (Silicon Pixel sensor +Front End Chip+ Module Control Chip (MCC)) go to an auto-disable state, where the Modules don’t send the data for storage. Modules become operational again after reconfiguration. The source of the problem is not fully understood. One possible source of the problem is traced to the occurrence of single event upset (SEU) in the MCC. Such a module goes to either a Timeout or Busy state. This report is the study of different types and rates of errors occurring in the Pixel data taking operation. Also, the study includes the error rate dependency on Pixel detector geometry.

  16. The impact of a closed-loop electronic prescribing and administration system on prescribing errors, administration errors and staff time: a before-and-after study.

    Science.gov (United States)

    Franklin, Bryony Dean; O'Grady, Kara; Donyai, Parastou; Jacklin, Ann; Barber, Nick

    2007-08-01

    To assess the impact of a closed-loop electronic prescribing, automated dispensing, barcode patient identification and electronic medication administration record (EMAR) system on prescribing and administration errors, confirmation of patient identity before administration, and staff time. Before-and-after study in a surgical ward of a teaching hospital, involving patients and staff of that ward. Closed-loop electronic prescribing, automated dispensing, barcode patient identification and EMAR system. Percentage of new medication orders with a prescribing error, percentage of doses with medication administration errors (MAEs) and percentage given without checking patient identity. Time spent prescribing and providing a ward pharmacy service. Nursing time on medication tasks. Prescribing errors were identified in 3.8% of 2450 medication orders pre-intervention and 2.0% of 2353 orders afterwards (pMedical staff required 15 s to prescribe a regular inpatient drug pre-intervention and 39 s afterwards (p = 0.03; t test). Time spent providing a ward pharmacy service increased from 68 min to 98 min each weekday (p = 0.001; t test); 22% of drug charts were unavailable pre-intervention. Time per drug administration round decreased from 50 min to 40 min (p = 0.006; t test); nursing time on medication tasks outside of drug rounds increased from 21.1% to 28.7% (p = 0.006; chi(2) test). A closed-loop electronic prescribing, dispensing and barcode patient identification system reduced prescribing errors and MAEs, and increased confirmation of patient identity before administration. Time spent on medication-related tasks increased.

  17. The impact of a closed‐loop electronic prescribing and administration system on prescribing errors, administration errors and staff time: a before‐and‐after study

    Science.gov (United States)

    Franklin, Bryony Dean; O'Grady, Kara; Donyai, Parastou; Jacklin, Ann; Barber, Nick

    2007-01-01

    Objectives To assess the impact of a closed‐loop electronic prescribing, automated dispensing, barcode patient identification and electronic medication administration record (EMAR) system on prescribing and administration errors, confirmation of patient identity before administration, and staff time. Design, setting and participants Before‐and‐after study in a surgical ward of a teaching hospital, involving patients and staff of that ward. Intervention Closed‐loop electronic prescribing, automated dispensing, barcode patient identification and EMAR system. Main outcome measures Percentage of new medication orders with a prescribing error, percentage of doses with medication administration errors (MAEs) and percentage given without checking patient identity. Time spent prescribing and providing a ward pharmacy service. Nursing time on medication tasks. Results Prescribing errors were identified in 3.8% of 2450 medication orders pre‐intervention and 2.0% of 2353 orders afterwards (pMedical staff required 15 s to prescribe a regular inpatient drug pre‐intervention and 39 s afterwards (p = 0.03; t test). Time spent providing a ward pharmacy service increased from 68 min to 98 min each weekday (p = 0.001; t test); 22% of drug charts were unavailable pre‐intervention. Time per drug administration round decreased from 50 min to 40 min (p = 0.006; t test); nursing time on medication tasks outside of drug rounds increased from 21.1% to 28.7% (p = 0.006; χ2 test). Conclusions A closed‐loop electronic prescribing, dispensing and barcode patient identification system reduced prescribing errors and MAEs, and increased confirmation of patient identity before administration. Time spent on medication‐related tasks increased. PMID:17693676

  18. In-plant reliability data base for nuclear plant components: a feasibility study on human error information

    International Nuclear Information System (INIS)

    Borkowski, R.J.; Fragola, J.R.; Schurman, D.L.; Johnson, J.W.

    1984-03-01

    This report documents the procedure and final results of a feasibility study which examined the usefulness of nuclear plant maintenance work requests in the IPRDS as tools for understanding human error and its influence on component failure and repair. Developed in this study were (1) a set of criteria for judging the quality of a plant maintenance record set for studying human error; (2) a scheme for identifying human errors in the maintenance records; and (3) two taxonomies (engineering-based and psychology-based) for categorizing and coding human error-related events

  19. Study of wavefront error and polarization of a side mounted infrared window

    Science.gov (United States)

    Liu, Jiaguo; Li, Lin; Hu, Xinqi; Yu, Xin

    2008-03-01

    The wavefront error and polarization of a side mounted infrared window made of ZnS are studied. The Infrared windows suffer from temperature gradient and stress during their launch process. Generally, the gradient in temperature changes the refractive index of the material whereas stress produces deformation and birefringence. In this paper, a thermal finite element analysis (FEA) of an IR window is presented. For this purpose, we employed an FEA program Ansys to obtain the time-varying temperature field. The deformation and stress of the window are derived from a structural FEA with the aerodynamic force and the temperature field previously obtained as being the loads. The deformation, temperature field, stress field, ray tracing and Jones Calculus are used to calculate the wavefront error and the change of polarization state.

  20. Simulation study on heterogeneous variance adjustment for observations with different measurement error variance

    DEFF Research Database (Denmark)

    Pitkänen, Timo; Mäntysaari, Esa A; Nielsen, Ulrik Sander

    2013-01-01

    of variance correction is developed for the same observations. As automated milking systems are becoming more popular the current evaluation model needs to be enhanced to account for the different measurement error variances of observations from automated milking systems. In this simulation study different...... models and different approaches to account for heterogeneous variance when observations have different measurement error variances were investigated. Based on the results we propose to upgrade the currently applied models and to calibrate the heterogeneous variance adjustment method to yield same genetic......The Nordic Holstein yield evaluation model describes all available milk, protein and fat test-day yields from Denmark, Finland and Sweden. In its current form all variance components are estimated from observations recorded under conventional milking systems. Also the model for heterogeneity...

  1. Wind Power Forecasting Error Frequency Analyses for Operational Power System Studies: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Florita, A.; Hodge, B. M.; Milligan, M.

    2012-08-01

    The examination of wind power forecasting errors is crucial for optimal unit commitment and economic dispatch of power systems with significant wind power penetrations. This scheduling process includes both renewable and nonrenewable generators, and the incorporation of wind power forecasts will become increasingly important as wind fleets constitute a larger portion of generation portfolios. This research considers the Western Wind and Solar Integration Study database of wind power forecasts and numerical actualizations. This database comprises more than 30,000 locations spread over the western United States, with a total wind power capacity of 960 GW. Error analyses for individual sites and for specific balancing areas are performed using the database, quantifying the fit to theoretical distributions through goodness-of-fit metrics. Insights into wind-power forecasting error distributions are established for various levels of temporal and spatial resolution, contrasts made among the frequency distribution alternatives, and recommendations put forth for harnessing the results. Empirical data are used to produce more realistic site-level forecasts than previously employed, such that higher resolution operational studies are possible. This research feeds into a larger work of renewable integration through the links wind power forecasting has with various operational issues, such as stochastic unit commitment and flexible reserve level determination.

  2. Financial impact of errors in business forecasting: a comparative study of linear models and neural networks

    Directory of Open Access Journals (Sweden)

    Claudimar Pereira da Veiga

    2012-08-01

    Full Text Available The importance of demand forecasting as a management tool is a well documented issue. However, it is difficult to measure costs generated by forecasting errors and to find a model that assimilate the detailed operation of each company adequately. In general, when linear models fail in the forecasting process, more complex nonlinear models are considered. Although some studies comparing traditional models and neural networks have been conducted in the literature, the conclusions are usually contradictory. In this sense, the objective was to compare the accuracy of linear methods and neural networks with the current method used by the company. The results of this analysis also served as input to evaluate influence of errors in demand forecasting on the financial performance of the company. The study was based on historical data from five groups of food products, from 2004 to 2008. In general, one can affirm that all models tested presented good results (much better than the current forecasting method used, with mean absolute percent error (MAPE around 10%. The total financial impact for the company was 6,05% on annual sales.

  3. Medication Errors in a Swiss Cardiovascular Surgery Department: A Cross-Sectional Study Based on a Novel Medication Error Report Method

    Directory of Open Access Journals (Sweden)

    Kaspar Küng

    2013-01-01

    Full Text Available The purpose of this study was (1 to determine frequency and type of medication errors (MEs, (2 to assess the number of MEs prevented by registered nurses, (3 to assess the consequences of ME for patients, and (4 to compare the number of MEs reported by a newly developed medication error self-reporting tool to the number reported by the traditional incident reporting system. We conducted a cross-sectional study on ME in the Cardiovascular Surgery Department of Bern University Hospital in Switzerland. Eligible registered nurses ( involving in the medication process were included. Data on ME were collected using an investigator-developed medication error self reporting tool (MESRT that asked about the occurrence and characteristics of ME. Registered nurses were instructed to complete a MESRT at the end of each shift even if there was no ME. All MESRTs were completed anonymously. During the one-month study period, a total of 987 MESRTs were returned. Of the 987 completed MESRTs, 288 (29% indicated that there had been an ME. Registered nurses reported preventing 49 (5% MEs. Overall, eight (2.8% MEs had patient consequences. The high response rate suggests that this new method may be a very effective approach to detect, report, and describe ME in hospitals.

  4. Study on the methodology for predicting and preventing errors to improve reliability of maintenance task in nuclear power plant

    International Nuclear Information System (INIS)

    Hanafusa, Hidemitsu; Iwaki, Toshio; Embrey, D.

    2000-01-01

    The objective of this study was to develop and effective methodology for predicting and preventing errors in nuclear power plant maintenance tasks. A method was established by which chief maintenance personnel can predict and reduce errors when reviewing the maintenance procedures and while referring to maintenance supporting systems and methods in other industries including aviation and chemical plant industries. The method involves the following seven steps: 1. Identification of maintenance tasks. 2. Specification of important tasks affecting safety. 3. Assessment of human errors occurring during important tasks. 4. Identification of Performance Degrading Factors. 5. Dividing important tasks into sub-tasks. 6. Extraction of errors using Predictive Human Error Analysis (PHEA). 7. Development of strategies for reducing errors and for recovering from errors. By way of a trial, this method was applied to the pump maintenance procedure in nuclear power plants. This method is believed to be capable of identifying the expected errors in important tasks and supporting the development of error reduction measures. By applying this method, the number of accidents resulting form human errors during maintenance can be reduced. Moreover, the maintenance support base using computers was developed. (author)

  5. Systematic Analysis of Video Data from Different Human-Robot Interaction Studies: A Categorisation of Social Signals During Error Situations

    OpenAIRE

    Manuel eGiuliani; Nicole eMirnig; Gerald eStollnberger; Susanne eStadler; Roland eBuchner; Manfred eTscheligi

    2015-01-01

    Human?robot interactions are often affected by error situations that are caused by either the robot or the human. Therefore, robots would profit from the ability to recognize when error situations occur. We investigated the verbal and non-verbal social signals that humans show when error situations occur in human?robot interaction experiments. For that, we analyzed 201 videos of five human?robot interaction user studies with varying tasks from four independent projects. The analysis shows tha...

  6. Accounting for response misclassification and covariate measurement error improves power and reduces bias in epidemiologic studies.

    Science.gov (United States)

    Cheng, Dunlei; Branscum, Adam J; Stamey, James D

    2010-07-01

    To quantify the impact of ignoring misclassification of a response variable and measurement error in a covariate on statistical power, and to develop software for sample size and power analysis that accounts for these flaws in epidemiologic data. A Monte Carlo simulation-based procedure is developed to illustrate the differences in design requirements and inferences between analytic methods that properly account for misclassification and measurement error to those that do not in regression models for cross-sectional and cohort data. We found that failure to account for these flaws in epidemiologic data can lead to a substantial reduction in statistical power, over 25% in some cases. The proposed method substantially reduced bias by up to a ten-fold margin compared to naive estimates obtained by ignoring misclassification and mismeasurement. We recommend as routine practice that researchers account for errors in measurement of both response and covariate data when determining sample size, performing power calculations, or analyzing data from epidemiological studies. 2010 Elsevier Inc. All rights reserved.

  7. Study of Error Propagation in the Transformations of Dynamic Thermal Models of Buildings

    Directory of Open Access Journals (Sweden)

    Loïc Raillon

    2017-01-01

    Full Text Available Dynamic behaviour of a system may be described by models with different forms: thermal (RC networks, state-space representations, transfer functions, and ARX models. These models, which describe the same process, are used in the design, simulation, optimal predictive control, parameter identification, fault detection and diagnosis, and so on. Since more forms are available, it is interesting to know which one is the most suitable by estimating the sensitivity of the model to transform into a physical model, which is represented by a thermal network. A procedure for the study of error by Monte Carlo simulation and of factor prioritization is exemplified on a simple, but representative, thermal model of a building. The analysis of the propagation of errors and of the influence of the errors on the parameter estimation shows that the transformation from state-space representation to transfer function is more robust than the other way around. Therefore, if only one model is chosen, the state-space representation is preferable.

  8. A study on mechanical errors in Cone Beam Computed Tomography (CBCT) System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yi Seong; Yoo, Eun Jeong; Choi, Kyoung Sik [Dept. of Radiation Oncology, Anyang SAM Hospital, Anyang (Korea, Republic of); Lee, Jong Woo [Dept. of Radiation Oncology, Konkuk University Medical Center, Seoul (Korea, Republic of); Suh, Tae Suk [Dept. of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of); Kim, Jeong Koo [Dept. of Radiological Science, Hanseo University, Seosan (Korea, Republic of)

    2013-06-15

    This study investigated the rate of setup variance by the rotating unbalance of gantry in image-guided radiation therapy. The equipments used linear accelerator(Elekta Synergy ™, UK) and a three-dimensional volume imaging mode(3D Volume View) in cone beam computed tomography(CBCT) system. 2D images obtained by rotating 360°and 180° were reconstructed to 3D image. Catpan503 phantom and homogeneous phantom were used to measure the setup errors. Ball-bearing phantom was used to check the rotation axis of the CBCT. The volume image from CBCT using Catphan503 phantom and homogeneous phantom were analyzed and compared to images from conventional CT in the six dimensional view(X, Y, Z, Roll, Pitch, and Yaw). The variance ratio of setup error were difference in X 0.6 mm, Y 0.5 mm, Z 0.5 mm when the gantry rotated 360° in orthogonal coordinate. whereas rotated 180°, the error measured 0.9 mm, 0.2 mm, 0.3 mm in X, Y, Z respectively. In the rotating coordinates, the more increased the rotating unbalance, the more raised average ratio of setup errors. The resolution of CBCT images showed 2 level of difference in the table recommended. CBCT had a good agreement compared to each recommended values which is the mechanical safety, geometry accuracy and image quality. The rotating unbalance of gentry vary hardly in orthogonal coordinate. However, in rotating coordinate of gantry exceeded the ±1° of recommended value. Therefore, when we do sophisticated radiation therapy six dimensional correction is needed.

  9. Calculation errors of Set-up in patients with tumor location of prostate. Exploratory study; Calculo de errores de Set-up en pacientes con localizacion tumoral de prostata. Estudio exploratorio

    Energy Technology Data Exchange (ETDEWEB)

    Donis Gil, S.; Robayna Duque, B. E.; Jimenez Sosa, A.; Hernandez Armas, O.; Gonzalez Martin, A. E.; Hernandez Armas, J.

    2013-07-01

    The calculation of SM is done from errors in positioning (set-up). These errors are calculated from movements in 3D of the patient. This paper is an exploratory study of 20 patients with tumor location of prostate in which errors of set-up for two protocols of work are evaluated. (Author)

  10. Pediatric Nurses' Perceptions of Medication Safety and Medication Error: A Mixed Methods Study.

    Science.gov (United States)

    Alomari, Albara; Wilson, Val; Solman, Annette; Bajorek, Beata; Tinsley, Patricia

    2017-05-30

    This study aims to outline the current workplace culture of medication practice in a pediatric medical ward. The objective is to explore the perceptions of nurses in a pediatric clinical setting as to why medication administration errors occur. As nurses have a central role in the medication process, it is essential to explore nurses' perceptions of the factors influencing the medication process. Without this understanding, it is difficult to develop effective prevention strategies aimed at reducing medication administration errors. Previous studies were limited to exploring a single and specific aspect of medication safety. The methods used in these studies were limited to survey designs which may lead to incomplete or inadequate information being provided. This study is phase 1 on an action research project. Data collection included a direct observation of nurses during medication preparation and administration, audit based on the medication policy, and guidelines and focus groups with nursing staff. A thematic analysis was undertaken by each author independently to analyze the observation notes and focus group transcripts. Simple descriptive statistics were used to analyze the audit data. The study was conducted in a specialized pediatric medical ward. Four key themes were identified from the combined quantitative and qualitative data: (1) understanding medication errors, (2) the busy-ness of nurses, (3) the physical environment, and (4) compliance with medication policy and practice guidelines. Workload, frequent interruptions to process, poor physical environment design, lack of preparation space, and impractical medication policies are identified as barriers to safe medication practice. Overcoming these barriers requires organizations to review medication process policies and engage nurses more in medication safety research and in designing clinical guidelines for their own practice.

  11. Human error analysis project (HEAP) - The fourth pilot study: verbal data for analysis of operator performance

    International Nuclear Information System (INIS)

    Braarud, Per Oeyvind; Droeyvoldsmo, Asgeir; Hollnagel, Erik

    1997-06-01

    This report is the second report from the Pilot study No. 4 within the Human Error Analyses Project (HEAP). The overall objective of HEAP is to provide a better understanding and explicit modelling of how and why ''cognitive errors'' occur. This study investigated the contribution from different verbal data sources for analysis of control room operator's performance. Operator's concurrent verbal report, retrospective verbal report, and process expert's comments were compared for their contribution to an operator performance measure. This study looked into verbal protocols for single operator and for team. The main findings of the study were that all the three verbal data sources could be used to study performance. There was a relative high overlap between the data sources, but also a unique contribution from each source. There was a common pattern in the types of operator activities the data sources gave information about. The operator's concurrent protocol overall contained slightly more information on the operator's activities than the other two verbal sources. The study also showed that concurrent verbal protocol is feasible and useful for analysis of team's activities during a scenario. (author)

  12. Linking Errors between Two Populations and Tests: A Case Study in International Surveys in Education

    Directory of Open Access Journals (Sweden)

    Dirk Hastedt

    2015-06-01

    Full Text Available This simulation study was prompted by the current increased interest in linking national studies to international large-scale assessments (ILSAs such as IEA's TIMSS, IEA's PIRLS, and OECD's PISA. Linkage in this scenario is achieved by including items from the international assessments in the national assessments on the premise that the average achievement scores from the latter can be linked to the international metric. In addition to raising issues associated with different testing conditions, administrative procedures, and the like, this approach also poses psychometric challenges. This paper endeavors to shed some light on the effects that can be expected, the linkage errors in particular, by countries using this practice. The ILSA selected for this simulation study was IEA TIMSS 2011, and the three countries used as the national assessment cases were Botswana, Honduras, and Tunisia, all of which participated in TIMSS 2011. The items selected as items common to the simulated national tests and the international test came from the Grade 4 TIMSS 2011 mathematics items that IEA released into the public domain after completion of this assessment. The findings of the current study show that linkage errors seemed to achieve acceptable levels if 30 or more items were used for the linkage, although the errors were still significantly higher compared to the TIMSS' cutoffs. Comparison of the estimated country averages based on the simulated national surveys and the averages based on the international TIMSS assessment revealed only one instance across the three countries of the estimates approaching parity. Also, the percentages of students in these countries who actually reached the defined benchmarks on the TIMSS achievement scale differed significantly from the results based on TIMSS and the results for the simulated national assessments. As a conclusion, we advise against using groups of released items from international assessments in national

  13. Measurement error in epidemiologic studies of air pollution based on land-use regression models.

    Science.gov (United States)

    Basagaña, Xavier; Aguilera, Inmaculada; Rivera, Marcela; Agis, David; Foraster, Maria; Marrugat, Jaume; Elosua, Roberto; Künzli, Nino

    2013-10-15

    Land-use regression (LUR) models are increasingly used to estimate air pollution exposure in epidemiologic studies. These models use air pollution measurements taken at a small set of locations and modeling based on geographical covariates for which data are available at all study participant locations. The process of LUR model development commonly includes a variable selection procedure. When LUR model predictions are used as explanatory variables in a model for a health outcome, measurement error can lead to bias of the regression coefficients and to inflation of their variance. In previous studies dealing with spatial predictions of air pollution, bias was shown to be small while most of the effect of measurement error was on the variance. In this study, we show that in realistic cases where LUR models are applied to health data, bias in health-effect estimates can be substantial. This bias depends on the number of air pollution measurement sites, the number of available predictors for model selection, and the amount of explainable variability in the true exposure. These results should be taken into account when interpreting health effects from studies that used LUR models.

  14. Organizational Climate, Stress, and Error in Primary Care: The MEMO Study

    National Research Council Canada - National Science Library

    Linzer, Mark; Manwell, Linda B; Mundt, Marlon; Williams, Eric; Maguire, Ann; McMurray, Julia; Plane, Mary B

    2005-01-01

    .... Physician surveys assessed office environment and organizational climate (OC). Stress was measured using a 4-item scale, past errors were self reported, and the likelihood of future errors was self-assessed using the OSPRE...

  15. Barriers to the medication error reporting process within the Irish National Ambulance Service, a focus group study.

    Science.gov (United States)

    Byrne, Eamonn; Bury, Gerard

    2018-02-08

    Incident reporting is vital to identifying pre-hospital medication safety issues because literature suggests that the majority of errors pre-hospital are self-identified. In 2016, the National Ambulance Service (NAS) reported 11 medication errors to the national body with responsibility for risk management and insurance cover. The Health Information and Quality Authority in 2014 stated that reporting of clinical incidents, of which medication errors are a subset, was not felt to be representative of the actual events occurring. Even though reporting systems are in place, the levels appear to be well below what might be expected. Little data is available to explain this apparent discrepancy. To identify, investigate and document the barriers to medication error reporting within the NAS. An independent moderator led four focus groups in March of 2016. A convenience sample of 18 frontline Paramedics and Advanced Paramedics from Cork City and County discussed medication errors and the medication error reporting process. The sessions were recorded and anonymised, and the data was analysed using a process of thematic analysis. Practitioners understood the value of reporting errors. Barriers to reporting included fear of consequences and ridicule, procedural ambiguity, lack of feedback and a perceived lack of both consistency and confidentiality. The perceived consequences for making an error included professional, financial, litigious and psychological. Staff appeared willing to admit errors in a psychologically safe environment. Barriers to reporting are in line with international evidence. Time constraints prevented achievement of thematic saturation. Further study is warranted.

  16. Conflict monitoring in speech processing : An fMRI study of error detection in speech production and perception

    NARCIS (Netherlands)

    Gauvin, Hanna; De Baene, W.; Brass, Marcel; Hartsuiker, Robert

    2016-01-01

    To minimize the number of errors in speech, and thereby facilitate communication, speech is monitored before articulation. It is, however, unclear at which level during speech production monitoring takes place, and what mechanisms are used to detect and correct errors. The present study investigated

  17. Error Analysis for Arithmetic Word Problems--A Case Study of Primary Three Students in One Singapore School

    Science.gov (United States)

    Cheng, Lu Pien

    2015-01-01

    In this study, ways in which 9-year old students from one Singapore school solved 1-step and 2-step word problems based on the three semantic structures were examined. The students' work and diagrams provided insights into the range of errors in word problem solving for 1- step and 2-step word problems. In particular, the errors provided some…

  18. Evaluating Method Engineer Performance: an error classification and preliminary empirical study

    Directory of Open Access Journals (Sweden)

    Steven Kelly

    1998-11-01

    Full Text Available We describe an approach to empirically test the use of metaCASE environments to model methods. Both diagrams and matrices have been proposed as a means for presenting the methods. These different paradigms may have their own effects on how easily and well users can model methods. We extend Batra's classification of errors in data modelling to cover metamodelling, and use it to measure the performance of a group of metamodellers using either diagrams or matrices. The tentative results from this pilot study confirm the usefulness of the classification, and show some interesting differences between the paradigms.

  19. Medication errors with the use of allopurinol and colchicine: a retrospective study of a national, anonymous Internet-accessible error reporting system.

    Science.gov (United States)

    Mikuls, Ted R; Curtis, Jeffrey R; Allison, Jeroan J; Hicks, Rodney W; Saag, Kenneth G

    2006-03-01

    To more closely assess medication errors in gout care, we examined data from a national, Internet-accessible error reporting program over a 5-year reporting period. We examined data from the MEDMARX database, covering the period from January 1, 1999 through December 31, 2003. For allopurinol and colchicine, we examined error severity, source, type, contributing factors, and healthcare personnel involved in errors, and we detailed errors resulting in patient harm. Causes of error and the frequency of other error characteristics were compared for gout medications versus other musculoskeletal treatments using the chi-square statistic. Gout medication errors occurred in 39% (n = 273) of facilities participating in the MEDMARX program. Reported errors were predominantly from the inpatient hospital setting and related to the use of allopurinol (n = 524), followed by colchicine (n = 315), probenecid (n = 50), and sulfinpyrazone (n = 2). Compared to errors involving other musculoskeletal treatments, allopurinol and colchicine errors were more often ascribed to problems with physician prescribing (7% for other therapies versus 23-39% for allopurinol and colchicine, p < 0.0001) and less often due to problems with drug administration or nursing error (50% vs 23-27%, p < 0.0001). Our results suggest that inappropriate prescribing practices are characteristic of errors occurring with the use of allopurinol and colchicine. Physician prescribing practices are a potential target for quality improvement interventions in gout care.

  20. Quantification of human errors in level-1 PSA studies in NUPEC/JINS

    International Nuclear Information System (INIS)

    Hirano, M.; Hirose, M.; Sugawara, M.; Hashiba, T.

    1991-01-01

    THERP (Technique for Human Error Rate Prediction) method is mainly adopted to evaluate the pre-accident and post-accident human error rates. Performance shaping factors are derived by taking Japanese operational practice into account. Several examples of human error rates with calculational procedures are presented. The important human interventions of typical Japanese NPPs are also presented. (orig./HP)

  1. Learning from Errors at Work: A Replication Study in Elder Care Nursing

    Science.gov (United States)

    Leicher, Veronika; Mulder, Regina H.; Bauer, Johannes

    2013-01-01

    Learning from errors is an important way of learning at work. In this article, we analyse conditions under which elder care nurses use errors as a starting point for the engagement in social learning activities (ESLA) in the form of joint reflection with colleagues on potential causes of errors and ways to prevent them in future. The goal of our…

  2. Prevalence, Nature, Severity and Risk Factors for Prescribing Errors in Hospital Inpatients: Prospective Study in 20 UK Hospitals.

    Science.gov (United States)

    Ashcroft, Darren M; Lewis, Penny J; Tully, Mary P; Farragher, Tracey M; Taylor, David; Wass, Valerie; Williams, Steven D; Dornan, Tim

    2015-09-01

    It has been suggested that doctors in their first year of post-graduate training make a disproportionate number of prescribing errors. This study aimed to compare the prevalence of prescribing errors made by first-year post-graduate doctors with that of errors by senior doctors and non-medical prescribers and to investigate the predictors of potentially serious prescribing errors. Pharmacists in 20 hospitals over 7 prospectively selected days collected data on the number of medication orders checked, the grade of prescriber and details of any prescribing errors. Logistic regression models (adjusted for clustering by hospital) identified factors predicting the likelihood of prescribing erroneously and the severity of prescribing errors. Pharmacists reviewed 26,019 patients and 124,260 medication orders; 11,235 prescribing errors were detected in 10,986 orders. The mean error rate was 8.8 % (95 % confidence interval [CI] 8.6-9.1) errors per 100 medication orders. Rates of errors for all doctors in training were significantly higher than rates for medical consultants. Doctors who were 1 year (odds ratio [OR] 2.13; 95 % CI 1.80-2.52) or 2 years in training (OR 2.23; 95 % CI 1.89-2.65) were more than twice as likely to prescribe erroneously. Prescribing errors were 70 % (OR 1.70; 95 % CI 1.61-1.80) more likely to occur at the time of hospital admission than when medication orders were issued during the hospital stay. No significant differences in severity of error were observed between grades of prescriber. Potentially serious errors were more likely to be associated with prescriptions for parenteral administration, especially for cardiovascular or endocrine disorders. The problem of prescribing errors in hospitals is substantial and not solely a problem of the most junior medical prescribers, particularly for those errors most likely to cause significant patient harm. Interventions are needed to target these high-risk errors by all grades of staff and hence

  3. Impact of Stewardship Interventions on Antiretroviral Medication Errors in an Urban Medical Center: A 3-Year, Multiphase Study.

    Science.gov (United States)

    Zucker, Jason; Mittal, Jaimie; Jen, Shin-Pung; Cheng, Lucy; Cennimo, David

    2016-03-01

    There is a high prevalence of HIV infection in Newark, New Jersey, with University Hospital admitting approximately 600 HIV-infected patients per year. Medication errors involving antiretroviral therapy (ART) could significantly affect treatment outcomes. The goal of this study was to evaluate the effectiveness of various stewardship interventions in reducing the prevalence of prescribing errors involving ART. This was a retrospective review of all inpatients receiving ART for HIV treatment during three distinct 6-month intervals over a 3-year period. During the first year, the baseline prevalence of medication errors was determined. During the second year, physician and pharmacist education was provided, and a computerized order entry system with drug information resources and prescribing recommendations was implemented. Prospective audit of ART orders with feedback was conducted in the third year. Analyses and comparisons were made across the three phases of this study. Of the 334 patients with HIV admitted in the first year, 45% had at least one antiretroviral medication error and 38% had uncorrected errors at the time of discharge. After education and computerized order entry, significant reductions in medication error rates were observed compared to baseline rates; 36% of 315 admissions had at least one error and 31% had uncorrected errors at discharge. While the prevalence of antiretroviral errors in year 3 was similar to that of year 2 (37% of 276 admissions), there was a significant decrease in the prevalence of uncorrected errors at discharge (12%) with the use of prospective review and intervention. Interventions, such as education and guideline development, can aid in reducing ART medication errors, but a committed stewardship program is necessary to elicit the greatest impact. © 2016 Pharmacotherapy Publications, Inc.

  4. Enhancing Intervention for Residual Rhotic Errors Via App-Delivered Biofeedback: A Case Study.

    Science.gov (United States)

    Byun, Tara McAllister; Campbell, Heather; Carey, Helen; Liang, Wendy; Park, Tae Hong; Svirsky, Mario

    2017-06-22

    Recent research suggests that visual-acoustic biofeedback can be an effective treatment for residual speech errors, but adoption remains limited due to barriers including high cost and lack of familiarity with the technology. This case study reports results from the first participant to complete a course of visual-acoustic biofeedback using a not-for-profit iOS app, Speech Therapist's App for /r/ Treatment. App-based biofeedback treatment for rhotic misarticulation was provided in weekly 30-min sessions for 20 weeks. Within-treatment progress was documented using clinician perceptual ratings and acoustic measures. Generalization gains were assessed using acoustic measures of word probes elicited during baseline, treatment, and maintenance sessions. Both clinician ratings and acoustic measures indicated that the participant significantly improved her rhotic production accuracy in trials elicited during treatment sessions. However, these gains did not transfer to generalization probes. This study provides a proof-of-concept demonstration that app-based biofeedback is a viable alternative to costlier dedicated systems. Generalization of gains to contexts without biofeedback remains a challenge that requires further study. App-delivered biofeedback could enable clinician-research partnerships that would strengthen the evidence base while providing enhanced treatment for children with residual rhotic errors. https://doi.org/10.23641/asha.5116318.

  5. Evaluating physician performance at individualizing care: a pilot study tracking contextual errors in medical decision making.

    Science.gov (United States)

    Weiner, Saul J; Schwartz, Alan; Yudkowsky, Rachel; Schiff, Gordon D; Weaver, Frances M; Goldberg, Julie; Weiss, Kevin B

    2007-01-01

    Clinical decision making requires 2 distinct cognitive skills: the ability to classify patients' conditions into diagnostic and management categories that permit the application of research evidence and the ability to individualize or-more specifically-to contextualize care for patients whose circumstances and needs require variation from the standard approach to care. The purpose of this study was to develop and test a methodology for measuring physicians' performance at contextualizing care and compare it to their performance at planning biomedically appropriate care. First, the authors drafted 3 cases, each with 4 variations, 3 of which are embedded with biomedical and/or contextual information that is essential to planning care. Once the cases were validated as instruments for assessing physician performance, 54 internal medicine residents were then presented with opportunities to make these preidentified biomedical or contextual errors, and data were collected on information elicitation and error making. The case validation process was successful in that, in the final iteration, the physicians who received the contextual variant of cases proposed an alternate plan of care to those who received the baseline variant 100% of the time. The subsequent piloting of these validated cases unmasked previously unmeasured differences in physician performance at contextualizing care. The findings, which reflect the performance characteristics of the study population, are presented. This pilot study demonstrates a methodology for measuring physician performance at contextualizing care and illustrates the contribution of such information to an overall assessment of physician practice.

  6. Comparative Study of Communication Error between Conventional and Digital MCR Operators in NPPs

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Geun; Seong, Poong Hyun [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2015-05-15

    In this regard, the appropriate communication is directly related to the efficient and safe system operation, and inappropriate communication is one of the main causes of the accidents in various industries since inappropriate communications can cause a lack of necessary information exchange between operators and lead to serious consequences in large process systems such as nuclear power plants. According to the study conducted by Y. Hirotsu in 2001, about 25 percents of human error caused incidents in NPPs were related to communication issues. Also, other studies were reported that 85 percents of human error caused incidents in aviation industry and 92 percents in railway industry were related to communication problems. Accordingly, the importance of the efforts for reducing inappropriate communications has been emphasized in order to enhance the safety of pre-described systems. As a result, the average ratio of inappropriate communication in digital MCRs was slightly higher than that in conventional MCRs when the average ratio of no communication in digital MCRs was much smaller than that in conventional MCRs. Regarding the average ratio of inappropriate communication, it can be inferred that operators are still more familiar to the conventional MCRs than digital MCRs. More case studies are required for more delicate comparison since there were only three examined cases for digital MCRs. However, similar result is expected because there are no differences in communication method, although there are many differences in the way of procedure proceeding.

  7. Reducing Individual Variation for fMRI Studies in Children by Minimizing Template Related Errors.

    Directory of Open Access Journals (Sweden)

    Jian Weng

    Full Text Available Spatial normalization is an essential process for group comparisons in functional MRI studies. In practice, there is a risk of normalization errors particularly in studies involving children, seniors or diseased populations and in regions with high individual variation. One way to minimize normalization errors is to create a study-specific template based on a large sample size. However, studies with a large sample size are not always feasible, particularly for children studies. The performance of templates with a small sample size has not been evaluated in fMRI studies in children. In the current study, this issue was encountered in a working memory task with 29 children in two groups. We compared the performance of different templates: a study-specific template created by the experimental population, a Chinese children template and the widely used adult MNI template. We observed distinct differences in the right orbitofrontal region among the three templates in between-group comparisons. The study-specific template and the Chinese children template were more sensitive for the detection of between-group differences in the orbitofrontal cortex than the MNI template. Proper templates could effectively reduce individual variation. Further analysis revealed a correlation between the BOLD contrast size and the norm index of the affine transformation matrix, i.e., the SFN, which characterizes the difference between a template and a native image and differs significantly across subjects. Thereby, we proposed and tested another method to reduce individual variation that included the SFN as a covariate in group-wise statistics. This correction exhibits outstanding performance in enhancing detection power in group-level tests. A training effect of abacus-based mental calculation was also demonstrated, with significantly elevated activation in the right orbitofrontal region that correlated with behavioral response time across subjects in the trained group.

  8. Comprehensive Anti-error Study on Power Grid Dispatching Based on Regional Regulation and Integration

    Science.gov (United States)

    Zhang, Yunju; Chen, Zhongyi; Guo, Ming; Lin, Shunsheng; Yan, Yinyang

    2018-01-01

    With the large capacity of the power system, the development trend of the large unit and the high voltage, the scheduling operation is becoming more frequent and complicated, and the probability of operation error increases. This paper aims at the problem of the lack of anti-error function, single scheduling function and low working efficiency for technical support system in regional regulation and integration, the integrated construction of the error prevention of the integrated architecture of the system of dispatching anti - error of dispatching anti - error of power network based on cloud computing has been proposed. Integrated system of error prevention of Energy Management System, EMS, and Operation Management System, OMS have been constructed either. The system architecture has good scalability and adaptability, which can improve the computational efficiency, reduce the cost of system operation and maintenance, enhance the ability of regional regulation and anti-error checking with broad development prospects.

  9. Management-changing errors in the recall of radiologic results — A pilot study

    International Nuclear Information System (INIS)

    Brus-Ramer, M.; Yerubandi, V.; Newhouse, J.H.

    2012-01-01

    Aim: To evaluate the occurrence of alterations to diagnostic information from radiological studies, which are altered by person-to-person communication and/or faulty recall, and whether they affect patient management Materials and methods: A structured telephone survey was conducted at a large tertiary care medical centre of house staff managing inpatients who had undergone chest, abdominal, or pelvic computed tomography (CT) or magnetic resonance imaging (MRI) and remained in the hospital at least 2 days later. Fifty-six physicians were surveyed regarding 98 patient cases. Each physician was asked how he or she first became aware of the results of the study. Each was then asked to recall the substance of radiological interpretation and to compare it with the radiology report. Each was then asked to assess the level of difference between the interpretations and whether management was affected. Results were correlated with the route by which interviewees became aware of the report, the report length, and whether the managing service was medical or surgical. Results: In nearly 15% (14/98) of cases, differences between the recalled and official results were such that patient management could have been (11.2%) or had already been affected (3.1%). There was no significant correlation between errors and either the route of report communication or the report length. Conclusion: There was a substantial rate of error in the recall and/or transmission of diagnostic radiological information, which was sufficiently severe to affect patient management.

  10. Study of principle error sources in gamma spectrometry. Application to cross sections measurement

    International Nuclear Information System (INIS)

    Majah, M. Ibn.

    1985-01-01

    The principle error sources in gamma spectrometry have been studied in purpose to measure cross sections with great precision. Three error sources have been studied: dead time and pile up which depend on counting rate, and coincidence effect that depends on the disintegration scheme of the radionuclide in question. A constant frequency pulse generator has been used to correct the counting loss due to dead time and pile up in cases of long and short disintegration periods. The loss due to coincidence effect can reach 25% and over, depending on the disintegration scheme and on the distance source-detector. After establishing the correction formula and verifying its validity for four examples: iron 56, scandium 48, antimony 120 and gold 196 m, an application has been done by measuring cross sections of nuclear reactions that lead to long disintegration periods which need short distance source-detector counting and thus correcting the loss due to dead time effect, pile up and coincidence effect. 16 refs., 45 figs., 25 tabs. (author)

  11. An empirical study on the human error recovery failure probability when using soft controls in NPP advanced MCRs

    International Nuclear Information System (INIS)

    Jang, Inseok; Kim, Ar Ryum; Jung, Wondea; Seong, Poong Hyun

    2014-01-01

    Highlights: • Many researchers have tried to understand human recovery process or step. • Modeling human recovery process is not sufficient to be applied to HRA. • The operation environment of MCRs in NPPs has changed by adopting new HSIs. • Recovery failure probability in a soft control operation environment is investigated. • Recovery failure probability here would be important evidence for expert judgment. - Abstract: It is well known that probabilistic safety assessments (PSAs) today consider not just hardware failures and environmental events that can impact upon risk, but also human error contributions. Consequently, the focus on reliability and performance management has been on the prevention of human errors and failures rather than the recovery of human errors. However, the recovery of human errors is as important as the prevention of human errors and failures for the safe operation of nuclear power plants (NPPs). For this reason, many researchers have tried to find a human recovery process or step. However, modeling the human recovery process is not sufficient enough to be applied to human reliability analysis (HRA), which requires human error and recovery probabilities. In this study, therefore, human error recovery failure probabilities based on predefined human error modes were investigated by conducting experiments in the operation mockup of advanced/digital main control rooms (MCRs) in NPPs. To this end, 48 subjects majoring in nuclear engineering participated in the experiments. In the experiments, using the developed accident scenario based on tasks from the standard post trip action (SPTA), the steam generator tube rupture (SGTR), and predominant soft control tasks, which are derived from the loss of coolant accident (LOCA) and the excess steam demand event (ESDE), all error detection and recovery data based on human error modes were checked with the performance sheet and the statistical analysis of error recovery/detection was then

  12. Automated evaluation of setup errors in carbon ion therapy using PET: Feasibility study

    International Nuclear Information System (INIS)

    Kuess, Peter; Hopfgartner, Johannes; Georg, Dietmar; Helmbrecht, Stephan; Fiedler, Fine; Birkfellner, Wolfgang; Enghardt, Wolfgang

    2013-01-01

    Purpose: To investigate the possibility of detecting patient mispositioning in carbon-ion therapy with particle therapy positron emission tomography (PET) in an automated image registration based manner. Methods: Tumors in the head and neck (H and N), pelvic, lung, and brain region were investigated. Biologically optimized carbon ion treatment plans were created with TRiP98. From these treatment plans, the reference β + -activity distributions were calculated using a Monte Carlo simulation. Setup errors were simulated by shifting or rotating the computed tomography (CT). The expected β + activity was calculated for each plan with shifts. Finally, the reference particle therapy PET images were compared to the “shifted” β + -activity distribution simulations using the Pearson's correlation coefficient (PCC). To account for different PET monitoring options the inbeam PET was compared to three different inroom scenarios. Additionally, the dosimetric effects of the CT misalignments were investigated. Results: The automated PCC detection of patient mispositioning was possible in the investigated indications for cranio-caudal shifts of 4 mm and more, except for prostate tumors. In the rather homogeneous pelvic region, the generated β + -activity distribution of the reference and compared PET image were too much alike. Thus, setup errors in this region could not be detected. Regarding lung lesions the detection strongly depended on the exact tumor location: in the center of the lung tumor misalignments could be detected down to 2 mm shifts while resolving shifts of tumors close to the thoracic wall was more challenging. Rotational shifts in the H and N and lung region of +6° and more could be detected using inroom PET and partly using inbeam PET. Comparing inroom PET to inbeam PET no obvious trend was found. However, among the inroom scenarios a longer measurement time was found to be advantageous. Conclusions: This study scopes the use of various particle therapy

  13. Practical Insights from Initial Studies Related to Human Error Analysis Project (HEAP)

    International Nuclear Information System (INIS)

    Follesoe, Knut; Kaarstad, Magnhild; Droeivoldsmo, Asgeir; Hollnagel, Erik; Kirwan; Barry

    1996-01-01

    This report presents practical insights made from an analysis of the three initial studies in the Human Error Analysis Project (HEAP), and the first study in the US NRC Staffing Project. These practical insights relate to our understanding of diagnosis in Nuclear Power Plant (NPP) emergency scenarios and, in particular, the factors that influence whether a diagnosis will succeed or fail. The insights reported here focus on three inter-related areas: (1) the diagnostic strategies and styles that have been observed in single operator and team-based studies; (2) the qualitative aspects of the key operator support systems, namely VDU interfaces, alarms, training and procedures, that have affected the outcome of diagnosis; and (3) the overall success rates of diagnosis and the error types that have been observed in the various studies. With respect to diagnosis, certain patterns have emerged from the various studies, depending on whether operators were alone or in teams, and on their familiarity with the process. Some aspects of the interface and alarm systems were found to contribute to diagnostic failures while others supported performance and recovery. Similar results were found for training and experience. Furthermore, the availability of procedures did not preclude the need for some diagnosis. With respect to HRA and PSA, it was possible to record the failure types seen in the studies, and in some cases to give crude estimates of the failure likelihood for certain scenarios. Although these insights are interim in nature, they do show the type of information that can be derived from these studies. More importantly, they clarify aspects of our understanding of diagnosis in NPP emergencies, including implications for risk assessment, operator support systems development, and for research into diagnosis in a broader range of fields than the nuclear power industry. (author)

  14. Relationship between refractive error and ocular biometrics in twin children: the Guangzhou Twin Eye Study.

    Science.gov (United States)

    Wang, Decai; Liu, Bin; Huang, Shengsong; Huang, Wenyong; He, Mingguang

    2014-09-01

    A cross-sectional study was conducted to explore the relationship between refractive error and ocular biometrics in children from the Guangzhou twin eye study. Twin participants aged 7-15 years were selected from Guangzhou Twin Eye Study. Ocular examinations included visual acuity measurement, ocular motility evaluation, autorefraction under cycloplegia, and anterior segment, media, and fundus examination. Axial length (AL), anterior chamber depth (ACD), and corneal curvature radius were measured using partial coherence laser interferometry. A multivariate linear regression model was used for statistical analysis. Twin children from Guangzhou city showed a decreased spherical equivalent with age, whereas both AL and ACD were increased and corneal curvature radius remained unchanged. When adjusted by age and gender, the data from 77% of twins presenting with spherical equivalent changes indicated that these were caused by predictable variables (R2 = 0.77, P biometrics. Refractive status is largely determined by axial length as the major factor.

  15. An Experimental Study of Medical Error Explanations: Do Apology, Empathy, Corrective Action, and Compensation Alter Intentions and Attitudes?

    Science.gov (United States)

    Nazione, Samantha; Pace, Kristin

    2015-01-01

    Medical malpractice lawsuits are a growing problem in the United States, and there is much controversy regarding how to best address this problem. The medical error disclosure framework suggests that apologizing, expressing empathy, engaging in corrective action, and offering compensation after a medical error may improve the provider-patient relationship and ultimately help reduce the number of medical malpractice lawsuits patients bring to medical providers. This study provides an experimental examination of the medical error disclosure framework and its effect on amount of money requested in a lawsuit, negative intentions, attitudes, and anger toward the provider after a medical error. Results suggest empathy may play a large role in providing positive outcomes after a medical error.

  16. Radiographer and radiologist perception error in reporting double contrast barium enemas: A pilot study

    International Nuclear Information System (INIS)

    Booth, Alison M.; Mannion, Richard A.J.

    2005-01-01

    Purpose: The practice of radiographers performing double contrast barium enemas (DCBE) is now widespread and in many centres the radiographer's opinion is, at least, contributing to a dual reporting system [Bewell J, Chapman AH. Radiographer performed barium enemas - results of a survey to assess progress. Radiography 1996;2:199-205; Leslie A, Virjee JP. Detection of colorectal carcinoma on double contrast barium enema when double reporting is routinely performed: an audit of current practice. Clin Radiol 2001;57:184-7; Culpan DG, Mitchell AJ, Hughes S, Nutman M, Chapman AH. Double contrast barium enema sensitivity: a comparison of studies by radiographers and radiologists. Clin Radiol 2002;57:604-7]. To ensure this change in practice does not lead to an increase in reporting errors, this study aimed to compare the perception abilities of radiographers with those of radiologists. Methods: Three gastro-intestinal (GI) radiographers and three consultant radiologists independently reported on a selection of 50 DCBE examinations, including the level of certainty in their comments for each examination. A blinded comparison of the results with an independent 'standard report' was recorded. Results: The results demonstrate there was no significant difference in perception error for any of the levels of certainty, for single reporting, for double reading by a radiographer/radiologist or by two radiologists. Conclusions: The study shows that radiographers can perceive abnormalities on DCBE at similar sensitivities and specificities as radiologists. While the participants in the study may be typical of a district general hospital, the nature of the study gives it limited external validity. As a pilot, the results demonstrate that, with slight modification, the methodology could be used for a larger study

  17. Fluid dynamic analysis and experimental study of a low radiation error temperature sensor

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jie, E-mail: yangjie396768@163.com [Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing 210044 (China); School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Liu, Qingquan, E-mail: andyucd@163.com [Jiangsu Key Laboratory of Meteorological Observation and Information Processing, Nanjing 210044 (China); Jiangsu Collaborative Innovation Center on Atmospheric Environment and Equipment Technology, Nanjing 210044 (China); Dai, Wei, E-mail: daiweiilove@163.com [Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing 210044 (China); School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Ding, Renhui, E-mail: drhabcd@sina.com [Jiangsu Meteorological Observation Center, Nanjing 210008 (China)

    2017-01-30

    To improve the air temperature observation accuracy, a low radiation error temperature sensor is proposed. A Computational Fluid Dynamics (CFD) method is implemented to obtain radiation errors under various environmental conditions. The low radiation error temperature sensor, a naturally ventilated radiation shield, a thermometer screen and an aspirated temperature measurement platform are characterized in the same environment to conduct the intercomparison. The aspirated platform served as an air temperature reference. The mean radiation errors of the naturally ventilated radiation shield and the thermometer screen are 0.57 °C and 0.32 °C, respectively. In contrast, the mean radiation error of the low radiation error temperature sensor is 0.05 °C. The low radiation error temperature sensor proposed in this research may be helpful to provide a relatively accurate air temperature measurement result. - Highlights: • A CFD method is applied to obtain a quantitative solution of radiation error. • A temperature sensor is proposed to minimize radiation error. • The radiation error of the temperature sensor is on the order of 0.05 °C.

  18. Error Patterns

    NARCIS (Netherlands)

    Hoede, C.; Li, Z.

    2001-01-01

    In coding theory the problem of decoding focuses on error vectors. In the simplest situation code words are $(0,1)$-vectors, as are the received messages and the error vectors. Comparison of a received word with the code words yields a set of error vectors. In deciding on the original code word,

  19. Modeling and Experimental Study of Soft Error Propagation Based on Cellular Automaton

    OpenAIRE

    He, Wei; Wang, Yueke; Xing, Kefei; Yang, Jianwei

    2016-01-01

    Aiming to estimate SEE soft error performance of complex electronic systems, a soft error propagation model based on cellular automaton is proposed and an estimation methodology based on circuit partitioning and error propagation is presented. Simulations indicate that different fault grade jamming and different coupling factors between cells are the main parameters influencing the vulnerability of the system. Accelerated radiation experiments have been developed to determine the main paramet...

  20. A phantom-based study for assessing the error and uncertainty of a neuronavigation system

    OpenAIRE

    Natalia Izquierdo-Cifuentes; Genaro Daza-Santacoloma; Walter Serna-Serna

    2017-01-01

    This document describes a calibration protocol with the intention to introduce a guide to standardize the metrological vocabulary among manufacturers of image-guided surgery systems. Two stages were developed to measure the errors and estimate the uncertainty of a neuronavigator in different situations, on the first one it was determined a mechanical error on a virtual model of an acrylic phantom, on the second it was determined a coordinate error on the computerized axial tomography scan of ...

  1. Study of errors in absolute flux density measurements of Cassiopeia A

    International Nuclear Information System (INIS)

    Kanda, M.

    1975-10-01

    An error analysis for absolute flux density measurements of Cassiopeia A is discussed. The lower-bound quadrature-accumulation error for state-of-the-art measurements of the absolute flux density of Cas A around 7 GHz is estimated to be 1.71% for 3 sigma limits. The corresponding practicable error for the careful but not state-of-the-art measurement is estimated to be 4.46% for 3 sigma limits

  2. Prevalence and risk factors of undercorrected refractive errors among Singaporean Malay adults: the Singapore Malay Eye Study.

    Science.gov (United States)

    Rosman, Mohamad; Wong, Tien Y; Tay, Wan-Ting; Tong, Louis; Saw, Seang-Mei

    2009-08-01

    To describe the prevalence and the risk factors of undercorrected refractive error in an adult urban Malay population. This population-based, cross-sectional study was conducted in Singapore in 3280 Malay adults, aged 40 to 80 years. All individuals were examined at a centralized clinic and underwent standardized interviews and assessment of refractive errors and presenting and best corrected visual acuities. Distance presenting visual acuity was monocularly measured by using a logarithm of the minimum angle of resolution (logMAR) number chart at a distance of 4 m, with the participants wearing their "walk-in" optical corrections (spectacles or contact lenses), if any. Refraction was determined by subjective refraction by trained, certified study optometrists. Best corrected visual acuity was monocularly assessed and recorded in logMAR scores using the same test protocol as was used for presenting visual acuity. Undercorrected refractive error was defined as an improvement of at least 0.2 logMAR (2 lines equivalent) in the best corrected visual acuity compared with the presenting visual acuity in the better eye. The mean age of the subjects included in our study was 58 +/- 11 years, and 52% of the subjects were women. The prevalence rate of undercorrected refractive error among Singaporean Malay adults in our study (n = 3115) was 20.4% (age-standardized prevalence rate, 18.3%). More of the women had undercorrected refractive error than the men (21.8% vs. 18.8%, P = 0.04). Undercorrected refractive error was also more common in subjects older than 50 years than in subjects aged 40 to 49 years (22.6% vs. 14.3%, P Malay adults with refractive errors was higher than that of the Singaporean Chinese adults with refractive errors. Undercorrected refractive error is a significant cause of correctable visual impairment among Singaporean Malay adults, affecting one in five persons.

  3. Comparison of community and hospital pharmacists' attitudes and behaviors on medication error disclosure to the patient: A pilot study.

    Science.gov (United States)

    Kim, ChungYun; Mazan, Jennifer L; Quiñones-Boex, Ana C

    To determine pharmacists' attitudes and behaviors on medication errors and their disclosure and to compare community and hospital pharmacists on such views. An online questionnaire was developed from previous studies on physicians' disclosure of errors. Questionnaire items included demographics, environment, personal experiences, and attitudes on medication errors and the disclosure process. An invitation to participate along with the link to the questionnaire was electronically distributed to members of two Illinois pharmacy associations. A follow-up reminder was sent 4 weeks after the original message. Data were collected for 3 months, and statistical analyses were performed with the use of IBM SPSS version 22.0. The overall response rate was 23.3% (n = 422). The average employed respondent was a 51-year-old white woman with a BS Pharmacy degree working in a hospital pharmacy as a clinical staff member. Regardless of practice settings, pharmacist respondents agreed that medication errors were inevitable and that a disclosure process is necessary. Respondents from community and hospital settings were further analyzed to assess any differences. Community pharmacist respondents were more likely to agree that medication errors were inevitable and that pharmacists should address the patient's emotions when disclosing an error. Community pharmacist respondents were also more likely to agree that the health care professional most closely involved with the error should disclose the error to the patient and thought that it was the pharmacists' responsibility to disclose the error. Hospital pharmacist respondents were more likely to agree that it was important to include all details in a disclosure process and more likely to disagree on putting a "positive spin" on the event. Regardless of practice setting, responding pharmacists generally agreed that errors should be disclosed to patients. There were, however, significant differences in their attitudes and behaviors

  4. Compensation of kinematic geometric parameters error and comparative study of accuracy testing for robot

    Science.gov (United States)

    Du, Liang; Shi, Guangming; Guan, Weibin; Zhong, Yuansheng; Li, Jin

    2014-12-01

    Geometric error is the main error of the industrial robot, and it plays a more significantly important fact than other error facts for robot. The compensation model of kinematic error is proposed in this article. Many methods can be used to test the robot accuracy, therefore, how to compare which method is better one. In this article, a method is used to compare two methods for robot accuracy testing. It used Laser Tracker System (LTS) and Three Coordinate Measuring instrument (TCM) to test the robot accuracy according to standard. According to the compensation result, it gets the better method which can improve the robot accuracy apparently.

  5. Modeling and Experimental Study of Soft Error Propagation Based on Cellular Automaton

    Directory of Open Access Journals (Sweden)

    Wei He

    2016-01-01

    Full Text Available Aiming to estimate SEE soft error performance of complex electronic systems, a soft error propagation model based on cellular automaton is proposed and an estimation methodology based on circuit partitioning and error propagation is presented. Simulations indicate that different fault grade jamming and different coupling factors between cells are the main parameters influencing the vulnerability of the system. Accelerated radiation experiments have been developed to determine the main parameters for raw soft error vulnerability of the module and coupling factors. Results indicate that the proposed method is feasible.

  6. Multivariate Error Covariance Estimates by Monte-Carlo Simulation for Assimilation Studies in the Pacific Ocean

    Science.gov (United States)

    Borovikov, Anna; Rienecker, Michele M.; Keppenne, Christian; Johnson, Gregory C.

    2004-01-01

    One of the most difficult aspects of ocean state estimation is the prescription of the model forecast error covariances. The paucity of ocean observations limits our ability to estimate the covariance structures from model-observation differences. In most practical applications, simple covariances are usually prescribed. Rarely are cross-covariances between different model variables used. Here a comparison is made between a univariate Optimal Interpolation (UOI) scheme and a multivariate OI algorithm (MvOI) in the assimilation of ocean temperature. In the UOI case only temperature is updated using a Gaussian covariance function and in the MvOI salinity, zonal and meridional velocities as well as temperature, are updated using an empirically estimated multivariate covariance matrix. Earlier studies have shown that a univariate OI has a detrimental effect on the salinity and velocity fields of the model. Apparently, in a sequential framework it is important to analyze temperature and salinity together. For the MvOI an estimation of the model error statistics is made by Monte-Carlo techniques from an ensemble of model integrations. An important advantage of using an ensemble of ocean states is that it provides a natural way to estimate cross-covariances between the fields of different physical variables constituting the model state vector, at the same time incorporating the model's dynamical and thermodynamical constraints as well as the effects of physical boundaries. Only temperature observations from the Tropical Atmosphere-Ocean array have been assimilated in this study. In order to investigate the efficacy of the multivariate scheme two data assimilation experiments are validated with a large independent set of recently published subsurface observations of salinity, zonal velocity and temperature. For reference, a third control run with no data assimilation is used to check how the data assimilation affects systematic model errors. While the performance of the

  7. A Conceptual Design Study for the Error Field Correction Coil Power Supply in JT-60SA

    International Nuclear Information System (INIS)

    Matsukawa, M.; Shimada, K.; Yamauchi, K.; Gaio, E.; Ferro, A.; Novello, L.

    2013-01-01

    This paper describes a conceptual design study for the circuit configuration of the Error Field Correction Coil (EFCC) power supply (PS) to maximize the expected performance with reasonable cost in JT-60SA. The EFCC consists of eighteen sector coils installed inside the vacuum vessel, six in the toroidal direction and three in the poloidal direction, each one rated for 30 kA-turn. As a result, star point connection is proposed for each group of six EFCC coils installed cyclically in the toroidal direction for decoupling with poloidal field coils. In addition, a six phase inverter which is capable of controlling each phase current was chosen as PS topology to ensure higher flexibility of operation with reasonable cost.

  8. Pressurized water reactor monitoring. Study of detection, diagnostic and estimation methods (least error squares and filtering)

    International Nuclear Information System (INIS)

    Gillet, M.

    1986-07-01

    This thesis presents a study for the surveillance of the ''primary coolant circuit inventory monitoring'' of a pressurized water reactor. A reference model is developed in view of an automatic system ensuring detection and diagnostic in real time. The methods used for the present application are statistical tests and a method related to pattern recognition. The estimation of failures detected, difficult owing to the non-linearity of the problem, is treated by the least error squares method of the predictor or corrector type, and by filtering. It is in this frame that a new optimized method with superlinear convergence is developed, and that a segmented linearization of the model is introduced, in view of a multiple filtering [fr

  9. On the a priori estimation of collocation error covariance functions: a feasibility study

    DEFF Research Database (Denmark)

    Arabelos, D.N.; Forsberg, René; Tscherning, C.C.

    2007-01-01

    and the associated error covariance functions were conducted in the Arctic region north of 64 degrees latitude. The correlation between the known features of the data and the parameters variance and correlation length of the computed error covariance functions was estimated using multiple regression analysis...

  10. Drug administration errors in an institution for individuals with intellectual disability : an observational study

    NARCIS (Netherlands)

    van den Bemt, P M L A; Robertz, R; de Jong, A L; van Roon, E N; Leufkens, H G M

    BACKGROUND: Medication errors can result in harm, unless barriers to prevent them are present. Drug administration errors are less likely to be prevented, because they occur in the last stage of the drug distribution process. This is especially the case in non-alert patients, as patients often form

  11. The study of CD side to side error in line/space pattern caused by post-exposure bake effect

    Science.gov (United States)

    Huang, Jin; Guo, Eric; Ge, Haiming; Lu, Max; Wu, Yijun; Tian, Mingjing; Yan, Shichuan; Wang, Ran

    2016-10-01

    In semiconductor manufacturing, as the design rule has decreased, the ITRS roadmap requires crucial tighter critical dimension (CD) control. CD uniformity is one of the necessary parameters to assure good performance and reliable functionality of any integrated circuit (IC) [1] [2], and towards the advanced technology nodes, it is a challenge to control CD uniformity well. The study of corresponding CD Uniformity by tuning Post-Exposure bake (PEB) and develop process has some significant progress[3], but CD side to side error happening to some line/space pattern are still found in practical application, and the error has approached to over the uniformity tolerance. After details analysis, even though use several developer types, the CD side to side error has not been found significant relationship to the developing. In addition, it is impossible to correct the CD side to side error by electron beam correction as such error does not appear in all Line/Space pattern masks. In this paper the root cause of CD side to side error is analyzed and the PEB module process are optimized as a main factor for improvement of CD side to side error.

  12. Study of maintenance skill-work based on PSFs and error category

    International Nuclear Information System (INIS)

    Nagata, Manabu; Yukimachi, Takeo; Hasegawa, Toshio

    2001-01-01

    In this investigation, the skill-types of skill-work are clarified according to the human error data on the maintenance works at nuclear power plants. At first, the causal PSFs of the errors are extracted from the data and some of the skill-types are characterized as results from factor analysis. Moreover, the skill-work model is reexamined on the basis of the contents of the human error data and the error category corresponding to the data. Furthermore, integrating the tendency of the causal PSFs and the actual error category concerning each skill-type, an extended skill-work model was developed with a flow-chart representation as a tentative stage of the investigation. (author)

  13. Using a site-specific technical error to establish training responsiveness: a preliminary explorative study.

    Science.gov (United States)

    Weatherwax, Ryan M; Harris, Nigel K; Kilding, Andrew E; Dalleck, Lance C

    2018-01-01

    Even though cardiorespiratory fitness (CRF) training elicits numerous health benefits, not all individuals have positive training responses following a structured CRF intervention. It has been suggested that the technical error (TE), a combination of biological variability and measurement error, should be used to establish specific training responsiveness criteria to gain further insight on the effectiveness of the training program. To date, most training interventions use an absolute change or a TE from previous findings, which do not take into consideration the training site and equipment used to establish training outcomes or the specific cohort being evaluated. The purpose of this investigation was to retrospectively analyze training responsiveness of two CRF training interventions using two common criteria and a site-specific TE. Sixteen men and women completed two maximal graded exercise tests and verification bouts to identify maximal oxygen consumption (VO 2 max) and establish a site-specific TE. The TE was then used to retrospectively analyze training responsiveness in comparison to commonly used criteria: percent change of >0% and >+5.6% in VO 2 max. The TE was found to be 7.7% for relative VO 2 max. χ 2 testing showed significant differences in all training criteria for each intervention and pooled data from both interventions, except between %Δ >0 and %Δ >+7.7% in one of the investigations. Training nonresponsiveness ranged from 11.5% to 34.6%. Findings from the present study support the utility of site-specific TE criterion to quantify training responsiveness. A similar methodology of establishing a site-specific and even cohort specific TE should be considered to establish when true cardiorespiratory training adaptations occur.

  14. Medication errors with the use of allopurinol and colchicine : A retrospective study of a national, anonymous Internet-accessible error reporting system

    NARCIS (Netherlands)

    Mikuls, TR; Curtis, [No Value; Allison, JJ; Hicks, RW; Saag, KG

    Objectives. To more closely assess medication errors in gout care, we examined data from a national, Internet-accessible error reporting program over a 5-year reporting period. Methods. We examined data from the MEDMARX (TM) database, covering the period from January 1, 1999 through December 31,

  15. (How) do we learn from errors? A prospective study of the link between the ward's learning practices and medication administration errors.

    Science.gov (United States)

    Drach-Zahavy, A; Somech, A; Admi, H; Peterfreund, I; Peker, H; Priente, O

    2014-03-01

    Attention in the ward should shift from preventing medication administration errors to managing them. Nevertheless, little is known in regard with the practices nursing wards apply to learn from medication administration errors as a means of limiting them. To test the effectiveness of four types of learning practices, namely, non-integrated, integrated, supervisory and patchy learning practices in limiting medication administration errors. Data were collected from a convenient sample of 4 hospitals in Israel by multiple methods (observations and self-report questionnaires) at two time points. The sample included 76 wards (360 nurses). Medication administration error was defined as any deviation from prescribed medication processes and measured by a validated structured observation sheet. Wards' use of medication administration technologies, location of the medication station, and workload were observed; learning practices and demographics were measured by validated questionnaires. Results of the mixed linear model analysis indicated that the use of technology and quiet location of the medication cabinet were significantly associated with reduced medication administration errors (estimate=.03, perrors (estimate=.04, plearning practices, supervisory learning was the only practice significantly linked to reduced medication administration errors (estimate=-.04, plearning were significantly linked to higher levels of medication administration errors (estimate=-.03, plearning was not associated with it (p>.05). How wards manage errors might have implications for medication administration errors beyond the effects of typical individual, organizational and technology risk factors. Head nurse can facilitate learning from errors by "management by walking around" and monitoring nurses' medication administration behaviors. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Study of the Switching Errors in an RSFQ Switch by Using a Computerized Test Setup

    International Nuclear Information System (INIS)

    Kim, Se Hoon; Baek, Seung Hun; Yang, Jung Kuk; Kim, Jun Ho; Kang, Joon Hee

    2005-01-01

    The problem of fluctuation-induced digital errors in a rapid single flux quantum (RSFQ) circuit has been a very important issue. In this work, we calculated the bit error rate of an RSFQ switch used in superconductive arithmetic logic unit (ALU). RSFQ switch should have a very low error rate in the optimal bias. Theoretical estimates of the RSFQ error rate are on the order of 10 -50 per bit operation. In this experiment, we prepared two identical circuits placed in parallel. Each circuit was composed of 10 Josephson transmission lines (JTLs) connected in series with an RSFQ switch placed in the middle of the 10 JTLs. We used a splitter to feed the same input signal to both circuits. The outputs of the two circuits were compared with an RSFQ exclusive OR (XOR) to measure the bit error rate of the RSFQ switch. By using a computerized bit-error-rate test setup, we measured the bit error rate of 2.18 x 10 -12 when the bias to the RSFQ switch was 0.398 mA that was quite off from the optimum bias of 0.6 mA.

  17. Consanguinity, endogamy and inborn errors of metabolism in Oman: a cross-sectional study.

    Science.gov (United States)

    Al-Thihli, Khalid; Al-Murshedi, Fathiya; Al-Hashmi, Nadia; Al-Mamari, Watfa; Islam, M Mazharul; Al-Yahyaee, Said A

    2014-01-01

    The Sultanate of Oman, like many other Arab countries, has relatively high rates of consanguinity. Reports suggest that the incidence of inborn errors of metabolism (IEM) is also high in Oman. This retrospective cross-sectional study was designed to evaluate the number of patients with IEM being followed at the only two tertiary centers in Oman treating such patients, and to calculate the consanguinity rates among these families. The electronic medical records of all patients were reviewed for demographic and clinical characteristics. A total of 285 patients with IEM were being followed at the 2 centers involved; 162 (56.8%) were male and 123 (43.2%) were female. The history of consanguinity was documented or available for 241 patients: 229 patients (95%) were born to consanguineous parents related as second cousins or closer. First-cousin marriages were reported in 191 families (79.3%), while 31 patients (12.9%) were born to second cousins. The parents of 5 patients (2%) were related as double first cousins, and 2 patients (1%) were born to first cousins once removed. The average coefficient of inbreeding (F) in our study was 0.081. Seventeen patients (6%) had associated comorbid conditions other than IEM. Our study highlights the clinical burden of IEM in Oman and emphasizes the high consanguinity rates among the parents of affected patients. © 2014 S. Karger AG, Basel

  18. Berkson error adjustment and other exposure surrogates in occupational case-control studies, with application to the Canadian INTEROCC study.

    Science.gov (United States)

    Oraby, Tamer; Sivaganesan, Siva; Bowman, Joseph D; Kincl, Laurel; Richardson, Lesley; McBride, Mary; Siemiatycki, Jack; Cardis, Elisabeth; Krewski, Daniel

    2018-05-01

    Many epidemiological studies assessing the relationship between exposure and disease are carried out without data on individual exposures. When this barrier is encountered in occupational studies, the subject exposures are often evaluated with a job-exposure matrix (JEM), which consists of mean exposure for occupational categories measured on a comparable group of workers. One of the objectives of the seven-country case-control study of occupational exposure and brain cancer risk, INTEROCC, was to investigate the relationship of occupational exposure to electromagnetic fields (EMF) in different frequency ranges and brain cancer risk. In this paper, we use the Canadian data from INTEROCC to estimate the odds of developing brain tumours due to occupational exposure to EMF. The first step was to find the best EMF exposure surrogate among the arithmetic mean, the geometric mean, and the mean of log-normal exposure distribution for each occupation in the JEM, in comparison to Berkson error adjustments via numerical approximation of the likelihood function. Contrary to previous studies of Berkson errors in JEMs, we found that the geometric mean was the best exposure surrogate. This analysis provided no evidence that cumulative lifetime exposure to extremely low frequency magnetic fields increases brain cancer risk, a finding consistent with other recent epidemiological studies.

  19. Modeling misidentification errors that result from use of genetic tags in capture-recapture studies

    Science.gov (United States)

    Yoshizaki, J.; Brownie, C.; Pollock, K.H.; Link, W.A.

    2011-01-01

    Misidentification of animals is potentially important when naturally existing features (natural tags) such as DNA fingerprints (genetic tags) are used to identify individual animals. For example, when misidentification leads to multiple identities being assigned to an animal, traditional estimators tend to overestimate population size. Accounting for misidentification in capture-recapture models requires detailed understanding of the mechanism. Using genetic tags as an example, we outline a framework for modeling the effect of misidentification in closed population studies when individual identification is based on natural tags that are consistent over time (non-evolving natural tags). We first assume a single sample is obtained per animal for each capture event, and then generalize to the case where multiple samples (such as hair or scat samples) are collected per animal per capture occasion. We introduce methods for estimating population size and, using a simulation study, we show that our new estimators perform well for cases with moderately high capture probabilities or high misidentification rates. In contrast, conventional estimators can seriously overestimate population size when errors due to misidentification are ignored. ?? 2009 Springer Science+Business Media, LLC.

  20. Study of dosimetry errors in the framework of a concerted international study about the risk of cancer in nuclear industry workers. Study of the errors made on dose estimations of 100 to 3000 keV photons

    International Nuclear Information System (INIS)

    Thierry Chef, I.

    2000-01-01

    Ionizing radiations are uncontested factors of cancer risk and the radioprotection standards are defined on the basis of epidemiological studies of persons exposed to high doses of radiations (atomic bombs and therapeutic medical exposures). An epidemiological study of cancer risk has been carried out on nuclear industry workers from 17 countries in order to check these standards and to directly evaluate the risk linked with long duration exposures to low doses. The techniques used to measure the workers' doses have changed with time and these evolutions have been different in the different countries considered. The study of dosimetry errors aims at estimating the compatibility of the doses with respect to the periods of time and to the countries, and at quantifying the errors that could have disturbed the dose measurements during the first years and their consideration in the risk estimation. A compilation of the information available about dosimetry in the participating countries has been performed and the main sources of errors have been identified. Experiments have been carried out to test the response of the dosimeters used and to evaluate the conditions of exposure inside the companies. The biases and uncertainties have been estimated per company and per period of time and the most important correspond to the oldest measurements performed. This study contributes also to improve the knowledge of the working conditions and of the preciseness of dose estimations. (J.S.)

  1. Sleep quality, posttraumatic stress, depression, and human errors in train drivers: a population-based nationwide study in South Korea.

    Science.gov (United States)

    Jeon, Hong Jin; Kim, Ji-Hae; Kim, Bin-Na; Park, Seung Jin; Fava, Maurizio; Mischoulon, David; Kang, Eun-Ho; Roh, Sungwon; Lee, Dongsoo

    2014-12-01

    Human error is defined as an unintended error that is attributable to humans rather than machines, and that is important to avoid to prevent accidents. We aimed to investigate the association between sleep quality and human errors among train drivers. Cross-sectional. Population-based. A sample of 5,480 subjects who were actively working as train drivers were recruited in South Korea. The participants were 4,634 drivers who completed all questionnaires (response rate 84.6%). None. The Pittsburgh Sleep Quality Index (PSQI), the Center for Epidemiologic Studies Depression Scale (CES-D), the Impact of Event Scale-Revised (IES-R), the State-Trait Anxiety Inventory (STAI), and the Korean Occupational Stress Scale (KOSS). Of 4,634 train drivers, 349 (7.5%) showed more than one human error per 5 y. Human errors were associated with poor sleep quality, higher PSQI total scores, short sleep duration at night, and longer sleep latency. Among train drivers with poor sleep quality, those who experienced severe posttraumatic stress showed a significantly higher number of human errors than those without. Multiple logistic regression analysis showed that human errors were significantly associated with poor sleep quality and posttraumatic stress, whereas there were no significant associations with depression, trait and state anxiety, and work stress after adjusting for age, sex, education years, marital status, and career duration. Poor sleep quality was found to be associated with more human errors in train drivers, especially in those who experienced severe posttraumatic stress. © 2014 Associated Professional Sleep Societies, LLC.

  2. FIASCO II failure to achieve a satisfactory cardiac outcome study: the elimination of system errors.

    Science.gov (United States)

    Farid, Shakil; Page, Aravinda; Jenkins, David; Jones, Mark T; Freed, Darren; Nashef, Samer A M

    2013-07-01

    Death in low-risk cardiac surgical patients provides a simple and accessible method by which modifiable causes of death can be identified. In the first FIASCO study published in 2009, local potentially modifiable causes of preventable death in low-risk patients with a logistic EuroSCORE of 0-2 undergoing cardiac surgery were inadequate myocardial protection and lack of clarity in the chain of responsibility. As a result, myocardial protection was improved, and a formalized system introduced to ensure clarity of the chain of responsibility in the care of all cardiac surgical patients. The purpose of the current study was to re-audit outcomes in low-risk patients to see if improvements have been achieved. Patients with a logistic EuroSCORE of 0-2 who had cardiac surgery from January 2006 to August 2012 were included. Data were prospectively collected and retrospectively analysed. The case notes of patients who died in hospital were subject to internal and external review and classified according to preventability. Two thousand five hundred and forty-nine patients with a logistic EuroSCORE of 0-2 underwent cardiac surgery during the study period. Seven deaths occurred in truly low-risk patients, giving a mortality of 0.27%. Of the seven, three were considered preventable and four non-preventable. Mortality was marginally lower than in our previous study (0.37%), and no death occurred as a result of inadequate myocardial protection or communication failures. We postulate that the regular study of such events in all institutions may unmask systemic errors that can be remedied to prevent or reduce future occurrences. We encourage all units to use this methodology to detect any similarly modifiable factors in their practice.

  3. Recent study, but not retrieval, of knowledge protects against learning errors.

    Science.gov (United States)

    Mullet, Hillary G; Umanath, Sharda; Marsh, Elizabeth J

    2014-11-01

    Surprisingly, people incorporate errors into their knowledge bases even when they have the correct knowledge stored in memory (e.g., Fazio, Barber, Rajaram, Ornstein, & Marsh, 2013). We examined whether heightening the accessibility of correct knowledge would protect people from later reproducing misleading information that they encountered in fictional stories. In Experiment 1, participants studied a series of target general knowledge questions and their correct answers either a few minutes (high accessibility of knowledge) or 1 week (low accessibility of knowledge) before exposure to misleading story references. In Experiments 2a and 2b, participants instead retrieved the answers to the target general knowledge questions either a few minutes or 1 week before the rest of the experiment. Reading the relevant knowledge directly before the story-reading phase protected against reproduction of the misleading story answers on a later general knowledge test, but retrieving that same correct information did not. Retrieving stored knowledge from memory might actually enhance the encoding of relevant misinformation.

  4. Task errors by emergency physicians are associated with interruptions, multitasking, fatigue and working memory capacity: a prospective, direct observation study.

    Science.gov (United States)

    Westbrook, Johanna I; Raban, Magdalena Z; Walter, Scott R; Douglas, Heather

    2018-01-09

    Interruptions and multitasking have been demonstrated in experimental studies to reduce individuals' task performance. These behaviours are frequently used by clinicians in high-workload, dynamic clinical environments, yet their effects have rarely been studied. To assess the relative contributions of interruptions and multitasking by emergency physicians to prescribing errors. 36 emergency physicians were shadowed over 120 hours. All tasks, interruptions and instances of multitasking were recorded. Physicians' working memory capacity (WMC) and preference for multitasking were assessed using the Operation Span Task (OSPAN) and Inventory of Polychronic Values. Following observation, physicians were asked about their sleep in the previous 24 hours. Prescribing errors were used as a measure of task performance. We performed multivariate analysis of prescribing error rates to determine associations with interruptions and multitasking, also considering physician seniority, age, psychometric measures, workload and sleep. Physicians experienced 7.9 interruptions/hour. 28 clinicians were observed prescribing 239 medication orders which contained 208 prescribing errors. While prescribing, clinicians were interrupted 9.4 times/hour. Error rates increased significantly if physicians were interrupted (rate ratio (RR) 2.82; 95% CI 1.23 to 6.49) or multitasked (RR 1.86; 95% CI 1.35 to 2.56) while prescribing. Having below-average sleep showed a >15-fold increase in clinical error rate (RR 16.44; 95% CI 4.84 to 55.81). WMC was protective against errors; for every 10-point increase on the 75-point OSPAN, a 19% decrease in prescribing errors was observed. There was no effect of polychronicity, workload, physician gender or above-average sleep on error rates. Interruptions, multitasking and poor sleep were associated with significantly increased rates of prescribing errors among emergency physicians. WMC mitigated the negative influence of these factors to an extent. These

  5. A study of the effect of measurement error in predictor variables in nondestructive assay

    International Nuclear Information System (INIS)

    Burr, Tom L.; Knepper, Paula L.

    2000-01-01

    It is not widely known that ordinary least squares estimates exhibit bias if there are errors in the predictor variables. For example, enrichment measurements are often fit to two predictors: Poisson-distributed count rates in the region of interest and in the background. Both count rates have at least random variation due to counting statistics. Therefore, the parameter estimates will be biased. In this case, the effect of bias is a minor issue because there is almost no interest in the parameters themselves. Instead, the parameters will be used to convert count rates into estimated enrichment. In other cases, this bias source is potentially more important. For example, in tomographic gamma scanning, there is an emission stage which depends on predictors (the 'system matrix') that are estimated with error during the transmission stage. In this paper, we provide background information for the impact and treatment of errors in predictors, present results of candidate methods of compensating for the effect, review some of the nondestructive assay situations where errors in predictors occurs, and provide guidance for when errors in predictors should be considered in nondestructive assay

  6. Shared and unshared exposure measurement error in occupational cohort studies and their effects on statistical inference in proportional hazards models

    Science.gov (United States)

    Laurier, Dominique; Rage, Estelle

    2018-01-01

    Exposure measurement error represents one of the most important sources of uncertainty in epidemiology. When exposure uncertainty is not or only poorly accounted for, it can lead to biased risk estimates and a distortion of the shape of the exposure-response relationship. In occupational cohort studies, the time-dependent nature of exposure and changes in the method of exposure assessment may create complex error structures. When a method of group-level exposure assessment is used, individual worker practices and the imprecision of the instrument used to measure the average exposure for a group of workers may give rise to errors that are shared between workers, within workers or both. In contrast to unshared measurement error, the effects of shared errors remain largely unknown. Moreover, exposure uncertainty and magnitude of exposure are typically highest for the earliest years of exposure. We conduct a simulation study based on exposure data of the French cohort of uranium miners to compare the effects of shared and unshared exposure uncertainty on risk estimation and on the shape of the exposure-response curve in proportional hazards models. Our results indicate that uncertainty components shared within workers cause more bias in risk estimation and a more severe attenuation of the exposure-response relationship than unshared exposure uncertainty or exposure uncertainty shared between individuals. These findings underline the importance of careful characterisation and modeling of exposure uncertainty in observational studies. PMID:29408862

  7. Justifications of policy-error correction: a case study of error correction in the Three Mile Island Nuclear Power Plant Accident

    International Nuclear Information System (INIS)

    Kim, Y.P.

    1982-01-01

    The sensational Three Mile Island Nuclear Power Plant Accident of 1979 raised many policy problems. Since the TMI accident, many authorities in the nation, including the President's Commission on TMI, Congress, GAO, as well as NRC, have researched lessons and recommended various corrective measures for the improvement of nuclear regulatory policy. As an effort to translate the recommendations into effective actions, the NRC developed the TMI Action Plan. How sound are these corrective actions. The NRC approach to the TMI Action Plan is justifiable to the extent that decisions were reached by procedures to reduce the effects of judgmental bias. Major findings from the NRC's effort to justify the corrective actions include: (A) The deficiencies and errors in the operations at the Three Mile Island Plant were not defined through a process of comprehensive analysis. (B) Instead, problems were identified pragmatically and segmentally, through empirical investigations. These problems tended to take one of two forms - determinate problems subject to regulatory correction on the basis of available causal knowledge, and indeterminate problems solved by interim rules plus continuing study. The information to justify the solution was adjusted to the problem characteristics. (C) Finally, uncertainty in the determinate problems was resolved by seeking more causal information, while efforts to resolve indeterminate problems relied upon collective judgment and a consensus rule governing decisions about interim resolutions

  8. A phantom-based study for assessing the error and uncertainty of a neuronavigation system

    Directory of Open Access Journals (Sweden)

    Natalia Izquierdo-Cifuentes

    2017-01-01

    Full Text Available This document describes a calibration protocol with the intention to introduce a guide to standardize the metrological vocabulary among manufacturers of image-guided surgery systems. Two stages were developed to measure the errors and estimate the uncertainty of a neuronavigator in different situations, on the first one it was determined a mechanical error on a virtual model of an acrylic phantom, on the second it was determined a coordinate error on the computerized axial tomography scan of the same phantom. Ten standard coordinates of the phantom were compared with the coordinates generated by the NeuroCPS. After measurement model was established, there were identified the sources of uncertainty and the data was processed according the guide to the expression of uncertainty in measurement.

  9. Monte Carlo simulation of expert judgments on human errors in chemical analysis--a case study of ICP-MS.

    Science.gov (United States)

    Kuselman, Ilya; Pennecchi, Francesca; Epstein, Malka; Fajgelj, Ales; Ellison, Stephen L R

    2014-12-01

    Monte Carlo simulation of expert judgments on human errors in a chemical analysis was used for determination of distributions of the error quantification scores (scores of likelihood and severity, and scores of effectiveness of a laboratory quality system in prevention of the errors). The simulation was based on modeling of an expert behavior: confident, reasonably doubting and irresolute expert judgments were taken into account by means of different probability mass functions (pmfs). As a case study, 36 scenarios of human errors which may occur in elemental analysis of geological samples by ICP-MS were examined. Characteristics of the score distributions for three pmfs of an expert behavior were compared. Variability of the scores, as standard deviation of the simulated score values from the distribution mean, was used for assessment of the score robustness. A range of the score values, calculated directly from elicited data and simulated by a Monte Carlo method for different pmfs, was also discussed from the robustness point of view. It was shown that robustness of the scores, obtained in the case study, can be assessed as satisfactory for the quality risk management and improvement of a laboratory quality system against human errors. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Refractive error, ocular biometry, and lens opalescence in an adult population: the Los Angeles Latino Eye Study.

    Science.gov (United States)

    Shufelt, Chrisandra; Fraser-Bell, Samantha; Ying-Lai, Mei; Torres, Mina; Varma, Rohit

    2005-12-01

    To characterize age- and gender-related differences in refractive error, ocular biometry, and lens opalescence (NOP) in a population-based sample of adult Latinos. Also assessed were the determinants of age-related refractive differences. Participants in the Los Angeles Latino Eye Study (LALES), a population-based study of Latinos aged 40 years and more, underwent an ophthalmic examination, including ultrasonic measurements of axial length (AL), vitreous chamber depth (VCD), anterior chamber depth (ACD), lens thickness (LT), and noncycloplegic automated and subjective refraction. Corneal curvature/power (CP) was measured using an autorefractor. NOP was graded at the slit lamp by an ophthalmologist using the Lens Opacity Classification System II. Age- and gender-related differences were calculated. Multiple regression models were used to identify the determinants of age-related refractive differences. Of the 6357 LALES participants, 5588 phakic individuals with biometric data were included in this analysis. Older individuals had shallower ACDs, thicker lenses, more NOP, and more hyperopia compared to younger individuals (P or = 0.05). Women had significantly shorter AL, shallower ACD and VCD, than did men (P < or = 0.01). The strongest determinants of refractive error were AL (primarily VCD) and CP. NOP was a small but significant determinant of refractive error in older individuals. Age- and gender-related differences in ocular biometric, refractive error, and NOP measurements are present in adult Latinos. While the relative contribution of NOP in determining refractive error is small, it is greater in older persons compared to younger individuals.

  11. Einstein's error

    International Nuclear Information System (INIS)

    Winterflood, A.H.

    1980-01-01

    In discussing Einstein's Special Relativity theory it is claimed that it violates the principle of relativity itself and that an anomalous sign in the mathematics is found in the factor which transforms one inertial observer's measurements into those of another inertial observer. The apparent source of this error is discussed. Having corrected the error a new theory, called Observational Kinematics, is introduced to replace Einstein's Special Relativity. (U.K.)

  12. The Iatroref study: medical errors are associated with symptoms of depression in ICU staff but not burnout or safety culture.

    Science.gov (United States)

    Garrouste-Orgeas, Maité; Perrin, Marion; Soufir, Lilia; Vesin, Aurélien; Blot, François; Maxime, Virginie; Beuret, Pascal; Troché, Gilles; Klouche, Kada; Argaud, Laurent; Azoulay, Elie; Timsit, Jean-François

    2015-02-01

    Staff behaviours to optimise patient safety may be influenced by burnout, depression and strength of the safety culture. We evaluated whether burnout, symptoms of depression and safety culture affected the frequency of medical errors and adverse events (selected using Delphi techniques) in ICUs. Prospective, observational, multicentre (31 ICUs) study from August 2009 to December 2011. Burnout, depression symptoms and safety culture were evaluated using the Maslach Burnout Inventory (MBI), CES-Depression scale and Safety Attitudes Questionnaire, respectively. Of 1,988 staff members, 1,534 (77.2 %) participated. Frequencies of medical errors and adverse events were 804.5/1,000 and 167.4/1,000 patient-days, respectively. Burnout prevalence was 3 or 40 % depending on the definition (severe emotional exhaustion, depersonalisation and low personal accomplishment; or MBI score greater than -9). Depression symptoms were identified in 62/330 (18.8 %) physicians and 188/1,204 (15.6 %) nurses/nursing assistants. Median safety culture score was 60.7/100 [56.8-64.7] in physicians and 57.5/100 [52.4-61.9] in nurses/nursing assistants. Depression symptoms were an independent risk factor for medical errors. Burnout was not associated with medical errors. The safety culture score had a limited influence on medical errors. Other independent risk factors for medical errors or adverse events were related to ICU organisation (40 % of ICU staff off work on the previous day), staff (specific safety training) and patients (workload). One-on-one training of junior physicians during duties and existence of a hospital risk-management unit were associated with lower risks. The frequency of selected medical errors in ICUs was high and was increased when staff members had symptoms of depression.

  13. Pilotaje en la detección de errores de prescripción de citostáticos Pilot study in the detection of errors in cytostatics prescription

    Directory of Open Access Journals (Sweden)

    María Antonieta Arbesú Michelena

    2004-12-01

    Full Text Available Dada la alta toxicidad de los citostáticos, resulta importante conocer la prevalencia de los errores de medicación ya que pueden provocar graves consecuencias en la respuesta al tratamiento de cada paciente. Con el objetivo de trazar una estrategia relacionada con la disminución de los posibles errores de prescripción se realizó un estudio piloto durante la semana comprendida entre el 15 y el 21 de diciembre de 2003, en el Servicio Quimioterapia Oncológica del Instituto de Oncología y Radiobiología, en 43 órdenes médicas. Los errores para el presente trabajo se clasificaron en errores por omisión (que dificultan la comprobación por parte del farmacéutico y errores de incorrección (que pueden ser potencialmente graves para el paciente. El total de errores fue de 299; en el caso de los errores por omisión, se destacan la no firma por el facultativo en las 43 prescripciones, así como el uso de abreviaturas, siglas o nombres comerciales en el 88,4 %. En relación con los errores graves se aprecia la no inclusión del peso y la talla en ninguna orden médica, la superficie corporal (sc errónea por encima en 15 casos (34,8 %, la subdosificación en 41 ocasiones (47,7 % y la no correspondencia del Protocolo según las Normas Institucionales con 17 incorrecciones. Se pudo conocer que la ocurrencia de errores de prescripción es alta en el Servicio, lo que demuestra que es importante protocolizar las órdenes médicas, lo que permitirá la disminución en el porcentaje de errores detectados en este estudio piloto y continuar profundizando al respecto.Due to the high toxicity of cytostatics it is important to know the prevalence of errors in medication, since they can cause serious consequences in the reponse to the treatment of every patient. In order to lay down a strategy related to the reduction of the possible errors in prescription, a pilot study was conducted in December 15-21, 2003, at the Oncological Chemotherapy Service of the

  14. A study on fatigue measurement of operators for human error prevention in NPPs

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Oh Yeon; Il, Jang Tong; Meiling, Luo; Hee, Lee Young [KAERI, Daejeon (Korea, Republic of)

    2012-10-15

    The identification and the analysis of individual factor of operators, which is one of the various causes of adverse effects in human performance, is not easy in NPPs. There are work types (including shift), environment, personality, qualification, training, education, cognition, fatigue, job stress, workload, etc in individual factors for the operators. Research at the Finnish Institute of Occupational Health (FIOH) reported that a 'burn out (extreme fatigue)' is related to alcohol dependent habits and must be dealt with using a stress management program. USNRC (U.S. Nuclear Regulatory Commission) developed FFD (Fitness for Duty) for improving the task efficiency and preventing human errors. 'Managing Fatigue' of 10CFR26 presented as requirements to control operator fatigue in NPPs. The committee explained that excessive fatigue is due to stressful work environments, working hours, shifts, sleep disorders, and unstable circadian rhythms. In addition, an International Labor Organization (ILO) developed and suggested a checklist to manage fatigue and job stress. In domestic, a systematic evaluation way is presented by the Final Safety Analysis Report (FSAR) chapter 18, Human Factors, in the licensing process. However, it almost focused on the interface design such as HMI (Human Machine Interface), not individual factors. In particular, because our country is in a process of the exporting the NPP to UAE, the development and setting of fatigue management technique is important and urgent to present the technical standard and FFD criteria to UAE. And also, it is anticipated that the domestic regulatory body applies the FFD program as the regulation requirement so that a preparation for that situation is required. In this paper, advanced researches are investigated to find the fatigue measurement and evaluation methods of operators in a high reliability industry. Also, this study tries to review the NRC report and discuss the causal factors and

  15. A study on fatigue measurement of operators for human error prevention in NPPs

    International Nuclear Information System (INIS)

    Ju, Oh Yeon; Il, Jang Tong; Meiling, Luo; Hee, Lee Young

    2012-01-01

    The identification and the analysis of individual factor of operators, which is one of the various causes of adverse effects in human performance, is not easy in NPPs. There are work types (including shift), environment, personality, qualification, training, education, cognition, fatigue, job stress, workload, etc in individual factors for the operators. Research at the Finnish Institute of Occupational Health (FIOH) reported that a 'burn out (extreme fatigue)' is related to alcohol dependent habits and must be dealt with using a stress management program. USNRC (U.S. Nuclear Regulatory Commission) developed FFD (Fitness for Duty) for improving the task efficiency and preventing human errors. 'Managing Fatigue' of 10CFR26 presented as requirements to control operator fatigue in NPPs. The committee explained that excessive fatigue is due to stressful work environments, working hours, shifts, sleep disorders, and unstable circadian rhythms. In addition, an International Labor Organization (ILO) developed and suggested a checklist to manage fatigue and job stress. In domestic, a systematic evaluation way is presented by the Final Safety Analysis Report (FSAR) chapter 18, Human Factors, in the licensing process. However, it almost focused on the interface design such as HMI (Human Machine Interface), not individual factors. In particular, because our country is in a process of the exporting the NPP to UAE, the development and setting of fatigue management technique is important and urgent to present the technical standard and FFD criteria to UAE. And also, it is anticipated that the domestic regulatory body applies the FFD program as the regulation requirement so that a preparation for that situation is required. In this paper, advanced researches are investigated to find the fatigue measurement and evaluation methods of operators in a high reliability industry. Also, this study tries to review the NRC report and discuss the causal factors and management

  16. Are Divorce Studies Trustworthy? The Effects of Survey Nonresponse and Response Errors

    Science.gov (United States)

    Mitchell, Colter

    2010-01-01

    Researchers rely on relationship data to measure the multifaceted nature of families. This article speaks to relationship data quality by examining the ramifications of different types of error on divorce estimates, models predicting divorce behavior, and models employing divorce as a predictor. Comparing matched survey and divorce certificate…

  17. Electrophysiological Endophenotypes and the Error-Related Negativity (ERN) in Autism Spectrum Disorder: A Family Study

    Science.gov (United States)

    Clawson, Ann; South, Mikle; Baldwin, Scott A.; Larson, Michael J.

    2017-01-01

    We examined the error-related negativity (ERN) as an endophenotype of ASD by comparing the ERN in families of ASD probands to control families. We hypothesized that ASD probands and families would display reduced-amplitude ERN relative to controls. Participants included 148 individuals within 39 families consisting of a mother, father, sibling,…

  18. Source Memory Errors Associated with Reports of Posttraumatic Flashbacks: A Proof of Concept Study

    Science.gov (United States)

    Brewin, Chris R.; Huntley, Zoe; Whalley, Matthew G.

    2012-01-01

    Flashbacks are involuntary, emotion-laden images experienced by individuals with posttraumatic stress disorder (PTSD). The qualities of flashbacks could under certain circumstances lead to source memory errors. Participants with PTSD wrote a trauma narrative and reported the experience of flashbacks. They were later presented with stimuli from…

  19. Error-enhanced augmented proprioceptive feedback in stroke rehabilitation training : a pilot study

    NARCIS (Netherlands)

    Molier, Birgit I.; de Boer, Jacintha; Prange, Gerdienke B.; Jannink, Michiel J.A.

    2009-01-01

    Augmented feedback plays an essential role in stroke rehabilitation therapy. When a force is applied to the arm, an augmented sensory (proprioceptive) cue is provided. The question was to find out if stroke patients can learn reach-and retrieval movements with error-enhanced augmented sensory

  20. A study and simulation of the impact of high-order aberrations to overlay error distribution

    Science.gov (United States)

    Sun, G.; Wang, F.; Zhou, C.

    2011-03-01

    With reduction of design rules, a number of corresponding new technologies, such as i-HOPC, HOWA and DBO have been proposed and applied to eliminate overlay error. When these technologies are in use, any high-order error distribution needs to be clearly distinguished in order to remove the underlying causes. Lens aberrations are normally thought to mainly impact the Matching Machine Overlay (MMO). However, when using Image-Based overlay (IBO) measurement tools, aberrations become the dominant influence on single machine overlay (SMO) and even on stage repeatability performance. In this paper, several measurements of the error distributions of the lens of SMEE SSB600/10 prototype exposure tool are presented. Models that characterize the primary influence from lens magnification, high order distortion, coma aberration and telecentricity are shown. The contribution to stage repeatability (as measured with IBO tools) from the above errors was predicted with simulator and compared to experiments. Finally, the drift of every lens distortion that impact to SMO over several days was monitored and matched with the result of measurements.

  1. Systematic analysis of video data from different human–robot interaction studies: a categorization of social signals during error situations

    Science.gov (United States)

    Giuliani, Manuel; Mirnig, Nicole; Stollnberger, Gerald; Stadler, Susanne; Buchner, Roland; Tscheligi, Manfred

    2015-01-01

    Human–robot interactions are often affected by error situations that are caused by either the robot or the human. Therefore, robots would profit from the ability to recognize when error situations occur. We investigated the verbal and non-verbal social signals that humans show when error situations occur in human–robot interaction experiments. For that, we analyzed 201 videos of five human–robot interaction user studies with varying tasks from four independent projects. The analysis shows that there are two types of error situations: social norm violations and technical failures. Social norm violations are situations in which the robot does not adhere to the underlying social script of the interaction. Technical failures are caused by technical shortcomings of the robot. The results of the video analysis show that the study participants use many head movements and very few gestures, but they often smile, when in an error situation with the robot. Another result is that the participants sometimes stop moving at the beginning of error situations. We also found that the participants talked more in the case of social norm violations and less during technical failures. Finally, the participants use fewer non-verbal social signals (for example smiling, nodding, and head shaking), when they are interacting with the robot alone and no experimenter or other human is present. The results suggest that participants do not see the robot as a social interaction partner with comparable communication skills. Our findings have implications for builders and evaluators of human–robot interaction systems. The builders need to consider including modules for recognition and classification of head movements to the robot input channels. The evaluators need to make sure that the presence of an experimenter does not skew the results of their user studies. PMID:26217266

  2. Systematic analysis of video data from different human-robot interaction studies: a categorization of social signals during error situations.

    Science.gov (United States)

    Giuliani, Manuel; Mirnig, Nicole; Stollnberger, Gerald; Stadler, Susanne; Buchner, Roland; Tscheligi, Manfred

    2015-01-01

    Human-robot interactions are often affected by error situations that are caused by either the robot or the human. Therefore, robots would profit from the ability to recognize when error situations occur. We investigated the verbal and non-verbal social signals that humans show when error situations occur in human-robot interaction experiments. For that, we analyzed 201 videos of five human-robot interaction user studies with varying tasks from four independent projects. The analysis shows that there are two types of error situations: social norm violations and technical failures. Social norm violations are situations in which the robot does not adhere to the underlying social script of the interaction. Technical failures are caused by technical shortcomings of the robot. The results of the video analysis show that the study participants use many head movements and very few gestures, but they often smile, when in an error situation with the robot. Another result is that the participants sometimes stop moving at the beginning of error situations. We also found that the participants talked more in the case of social norm violations and less during technical failures. Finally, the participants use fewer non-verbal social signals (for example smiling, nodding, and head shaking), when they are interacting with the robot alone and no experimenter or other human is present. The results suggest that participants do not see the robot as a social interaction partner with comparable communication skills. Our findings have implications for builders and evaluators of human-robot interaction systems. The builders need to consider including modules for recognition and classification of head movements to the robot input channels. The evaluators need to make sure that the presence of an experimenter does not skew the results of their user studies.

  3. An Empirical Study on Human Performance according to the Physical Environment (Potential Human Error Hazard) in Nuclear Power Plants

    International Nuclear Information System (INIS)

    Kim, Ar Ryum; Jang, In Seok; Seong, Proong Hyun

    2014-01-01

    The management of the physical environment for safety is more effective than a nuclear industry. Despite the physical environment such as lighting, noise satisfy with management standards, it can be background factors may cause human error and affect human performance. Because the consequence of extremely human error and human performance is high according to the physical environment, requirement standard could be covered with specific criteria. Particularly, in order to avoid human errors caused by an extremely low or rapidly-changing intensity illumination and masking effect such as power disconnection, plans for better visual environment and better function performances should be made as a careful study on efficient ways to manage and continue the better conditions is conducted

  4. Improving image quality in Electrical Impedance Tomography (EIT using Projection Error Propagation-based Regularization (PEPR technique: A simulation study

    Directory of Open Access Journals (Sweden)

    Tushar Kanti Bera

    2011-03-01

    Full Text Available A Projection Error Propagation-based Regularization (PEPR method is proposed and the reconstructed image quality is improved in Electrical Impedance Tomography (EIT. A projection error is produced due to the misfit of the calculated and measured data in the reconstruction process. The variation of the projection error is integrated with response matrix in each iterations and the reconstruction is carried out in EIDORS. The PEPR method is studied with the simulated boundary data for different inhomogeneity geometries. Simulated results demonstrate that the PEPR technique improves image reconstruction precision in EIDORS and hence it can be successfully implemented to increase the reconstruction accuracy in EIT.>doi:10.5617/jeb.158 J Electr Bioimp, vol. 2, pp. 2-12, 2011

  5. Assessing type I error and power of multistate Markov models for panel data-A simulation study.

    Science.gov (United States)

    Cassarly, Christy; Martin, Renee' H; Chimowitz, Marc; Peña, Edsel A; Ramakrishnan, Viswanathan; Palesch, Yuko Y

    2017-01-01

    Ordinal outcomes collected at multiple follow-up visits are common in clinical trials. Sometimes, one visit is chosen for the primary analysis and the scale is dichotomized amounting to loss of information. Multistate Markov models describe how a process moves between states over time. Here, simulation studies are performed to investigate the type I error and power characteristics of multistate Markov models for panel data with limited non-adjacent state transitions. The results suggest that the multistate Markov models preserve the type I error and adequate power is achieved with modest sample sizes for panel data with limited non-adjacent state transitions.

  6. A Simulation Study on Patient Setup Errors in External Beam Radiotherapy Using an Anthropomorphic 4D Phantom

    Directory of Open Access Journals (Sweden)

    Payam Samadi Miandoab

    2016-12-01

    Full Text Available Introduction Patient set-up optimization is required in radiotherapy to fill the accuracy gap between personalized treatment planning and uncertainties in the irradiation set-up. In this study, we aimed to develop a new method based on neural network to estimate patient geometrical setup using 4-dimensional (4D XCAT anthropomorphic phantom. Materials and Methods To access 4D modeling of motion of dynamic organs, a phantom employs non-uniform rational B-splines (NURBS-based Cardiac-Torso method with spline-based model to generate 4D computed tomography (CT images. First, to generate all the possible roto-translation positions, the 4D CT images were imported to Medical Image Data Examiner (AMIDE. Then, for automatic, real time verification of geometrical setup, an artificial neural network (ANN was proposed to estimate patient displacement, using training sets. Moreover, three external motion markers were synchronized with a patient couch position as reference points. In addition, the technique was validated through simulated activities by using reference 4D CT data acquired from five patients. Results The results indicated that patient geometrical set-up is highly depended on the comprehensiveness of training set. By using ANN model, the average patient setup error in XCAT phantom was reduced from 17.26 mm to 0.50 mm. In addition, in the five real patients, these average errors were decreased from 18.26 mm to 1.48 mm various breathing phases ranging from inhalation to exhalation were taken into account for patient setup. Uncertainty error assessment and different setup errors were obtained from each respiration phase. Conclusion This study proposed a new method for alignment of patient setup error using ANN model. Additionally, our correlation model (ANN could estimate true patient position with less error.

  7. Study of Frequency of Errors and Areas of Weaknesses in Business Communications Classes at Kapiolani Community College.

    Science.gov (United States)

    Uehara, Soichi

    This study was made to determine the most prevalent errors, areas of weakness, and their frequency in the writing of letters so that a course in business communications classes at Kapiolani Community College (Hawaii) could be prepared that would help students learn to write effectively. The 55 participating students were divided into two groups…

  8. Nine Loci for Ocular Axial Length Identified through Genome-wide Association Studies, Including Shared Loci with Refractive Error

    NARCIS (Netherlands)

    Cheng, Ching-Yu; Schache, Maria; Ikram, M. Kamran; Young, Terri L.; Guggenheim, Jeremy A.; Vitart, Veronique; Macgregor, Stuart; Verhoeven, Virginie J. M.; Barathi, Veluchamy A.; Liao, Jiemin; Hysi, Pirro G.; Bailey-Wilson, Joan E.; St Pourcain, Beate; Kemp, John P.; McMahon, George; Timpson, Nicholas J.; Evans, David M.; Montgomery, Grant W.; Mishra, Aniket; Wang, Ya Xing; Wang, Jie Jin; Rochtchina, Elena; Polasek, Ozren; Wright, Alan F.; Amin, Najaf; van Leeuwen, Elisabeth M.; Wilson, James F.; Pennell, Craig E.; van Duijn, Cornelia M.; de Jong, Paulus T. V. M.; Vingerling, Johannes R.; Zhou, Xin; Chen, Peng; Li, Ruoying; Tay, Wan-Ting; Zheng, Yingfeng; Chew, Merwyn; Burdon, Kathryn P.; Craig, Jamie E.; Iyengar, Sudha K.; Igo, Robert P.; Lass, Jonathan H.; Chew, Emily Y.; Haller, Toomas; Mihailov, Evelin; Metspalu, Andres; Wedenoja, Juho; Simpson, Claire L.; Wojciechowski, Robert; Chen, Wei

    2013-01-01

    Refractive errors are common eye disorders of public health importance worldwide. Ocular axial length (AL) is the major determinant of refraction and thus of myopia and hyperopia. We conducted a meta-analysis of genome-wide association studies for AL, combining 12,531 Europeans and 8,216 Asians. We

  9. N-acetylated metabolites in urine: proton nuclear magnetic resonance spectroscopic study on patients with inborn errors of metabolism.

    NARCIS (Netherlands)

    Engelke, U.F.H.; Liebrand-van Sambeek, M.L.F.; Jong, J.G.N. de; Leroy, J.G.; Morava, E.; Smeitink, J.A.M.; Wevers, R.A.

    2004-01-01

    BACKGROUND: There is no comprehensive analytical technique to analyze N-acetylated metabolites in urine. Many of these compounds are involved in inborn errors of metabolism. In the present study, we examined the potential of proton nuclear magnetic resonance ((1)H-NMR) spectroscopy as a tool to

  10. Study on a new framework of Human Reliability Analysis to evaluate soft control execution error in advanced MCRs of NPPs

    International Nuclear Information System (INIS)

    Jang, Inseok; Kim, Ar Ryum; Jung, Wondea; Seong, Poong Hyun

    2016-01-01

    Highlights: • The operation environment of MCRs in NPPs has changed by adopting new HSIs. • The operation action in NPP Advanced MCRs is performed by soft control. • New HRA framework should be considered in the HRA for advanced MCRs. • HRA framework for evaluation of soft control execution human error is suggested. • Suggested method will be helpful to analyze human reliability in advance MCRs. - Abstract: Since the Three Mile Island (TMI)-2 accident, human error has been recognized as one of the main causes of Nuclear Power Plant (NPP) accidents, and numerous studies related to Human Reliability Analysis (HRA) have been carried out. Most of these methods were developed considering the conventional type of Main Control Rooms (MCRs). However, the operating environment of MCRs in NPPs has changed with the adoption of new Human-System Interfaces (HSIs) that are based on computer-based technologies. The MCRs that include these digital technologies, such as large display panels, computerized procedures, and soft controls, are called advanced MCRs. Among the many features of advanced MCRs, soft controls are a particularly important feature because operating actions in NPP advanced MCRs are performed by soft control. Due to the differences in interfaces between soft control and hardwired conventional type control, different Human Error Probabilities (HEPs) and a new HRA framework should be considered in the HRA for advanced MCRs. To this end, a new framework of a HRA method for evaluating soft control execution human error is suggested by performing a soft control task analysis and the literature regarding widely accepted human error taxonomies is reviewed. Moreover, since most current HRA databases deal with operation in conventional MCRs and are not explicitly designed to deal with digital HSIs, empirical analysis of human error and error recovery considering soft controls under an advanced MCR mockup are carried out to collect human error data, which is

  11. Three-dimensional ray-tracing model for the study of advanced refractive errors in keratoconus.

    Science.gov (United States)

    Schedin, Staffan; Hallberg, Per; Behndig, Anders

    2016-01-20

    We propose a numerical three-dimensional (3D) ray-tracing model for the analysis of advanced corneal refractive errors. The 3D modeling was based on measured corneal elevation data by means of Scheimpflug photography. A mathematical description of the measured corneal surfaces from a keratoconus (KC) patient was used for the 3D ray tracing, based on Snell's law of refraction. A model of a commercial intraocular lens (IOL) was included in the analysis. By modifying the posterior IOL surface, it was shown that the imaging quality could be significantly improved. The RMS values were reduced by approximately 50% close to the retina, both for on- and off-axis geometries. The 3D ray-tracing model can constitute a basis for simulation of customized IOLs that are able to correct the advanced, irregular refractive errors in KC.

  12. Studying and comparing spectrum efficiency and error probability in GMSK and DBPSK modulation schemes

    Directory of Open Access Journals (Sweden)

    Juan Mario Torres Nova

    2008-09-01

    Full Text Available Gaussian minimum shift keying (GMSK and differential binary phase shift keying (DBPSK are two digital modulation schemes which are -frequently used in radio communication systems; however, there is interdependence in the use of its benefits (spectral efficiency, low bit error rate, low inter symbol interference, etc. Optimising one parameter creates problems for another; for example, the GMSK scheme succeeds in reducing bandwidth when introducing a Gaussian filter into an MSK (minimum shift ke-ying modulator in exchange for increasing inter-symbol interference in the system. The DBPSK scheme leads to lower error pro-bability, occupying more bandwidth; it likewise facilitates synchronous data transmission due to the receiver’s bit delay when re-covering a signal.

  13. Refractive error study in young subjects: results from a rural area in Paraguay

    Directory of Open Access Journals (Sweden)

    Isabel Signes-Soler

    2017-03-01

    Full Text Available AIM: To evaluate the distribution of refractive error in young subjects in a rural area of Paraguay in the context of an international cooperation campaign for the prevention of blindness. METHODS: A sample of 1466 young subjects (ranging from 3 to 22 years old, with a mean age of 11.21±3.63 years old, were examined to assess their distance visual acuity (VA and refractive error. The first screening examination performed by trained volunteers, included visual acuity testing, autokeratometry and non-cycloplegic autorefraction. Inclusion criteria for a second complete cycloplegic eye examination by an optometrist were VA <20/25 (0.10 logMAR or 0.8 decimal and/or corneal astigmatism ≥1.50 D. RESULTS: An uncorrected distance VA of 0 logMAR (1.0 decimal was found in 89.2% of children. VA <20/25 and/or corneal astigmatism ≥1.50 D was found in 3.9% of children (n=57, with a prevalence of hyperopia of 5.2% (0.2% of the total in this specific group. Furthermore, myopia (spherical equivalent ≤-0.5 D was found in 37.7% of the refracted children (0.5% of the total. The prevalence of refractive astigmatism (cylinder ≤-1.50 D was 15.8% (0.6% of the total. Visual impairment (VI (0.05≤VA≤0.3 was found in 12/114 (0.4% of the refracted eyes. Main causes for VI were refractive error (58%, retinal problems (17%, 2/12, albinism (17%, 2/12 and unknown (8%, 1/12. CONCLUSION: A low prevalence of refractive error has been found in this rural area of Paraguay, with higher prevalence of myopia than of hyperopia.

  14. A Case–Control Study Investigating Simulated Driving Errors in Ischemic Stroke and Subarachnoid Hemorrhage

    Directory of Open Access Journals (Sweden)

    Megan A. Hird

    2018-02-01

    Full Text Available BackgroundStroke can affect a variety of cognitive, perceptual, and motor abilities that are important for safe driving. Results of studies assessing post-stroke driving ability are quite variable in the areas and degree of driving impairment among patients. This highlights the need to consider clinical characteristics, including stroke subtype, when assessing driving performance.MethodsWe compared the simulated driving performance of 30 chronic stroke patients (>3 months, including 15 patients with ischemic stroke (IS and 15 patients with subarachnoid hemorrhage (SAH, and 20 age-matched controls. A preliminary analysis was performed, subdividing IS patients into right (n = 8 and left (n = 6 hemispheric lesions and SAH patients into middle cerebral artery (MCA, n = 5 and anterior communicating artery (n = 6 territory. A secondary analysis was conducted to investigate the cognitive correlates of driving.ResultsNine patients (30% exhibited impaired simulated driving performance, including four patients with IS (26.7% and five patients with SAH (33.3%. Both patients with IS (2.3 vs. 0.3, U = 76, p < 0.05 and SAH (1.5 vs. 0.3, U = 45, p < 0.001 exhibited difficulty with lane maintenance (% distance out of lane compared to controls. In addition, patients with IS exhibited difficulty with speed maintenance (% distance over speed limit; 8.9 vs. 4.1, U = 81, p < 0.05, whereas SAH patients exhibited difficulty with turning performance (total turning errors; 5.4 vs. 1.6, U = 39.5, p < 0.001. The Trail Making Test (TMT and Useful Field of View test were significantly associated with lane maintenance among patients with IS (rs > 0.6, p < 0.05. No cognitive tests showed utility among patients with SAH.ConclusionBoth IS and SAH exhibited difficulty with lane maintenance. Patients with IS additionally exhibited difficulty with speed maintenance, whereas SAH patients exhibited difficulty with turning

  15. Comparison of different spatial transformations applied to EEG data: A case study of error processing.

    Science.gov (United States)

    Cohen, Michael X

    2015-09-01

    The purpose of this paper is to compare the effects of different spatial transformations applied to the same scalp-recorded EEG data. The spatial transformations applied are two referencing schemes (average and linked earlobes), the surface Laplacian, and beamforming (a distributed source localization procedure). EEG data were collected during a speeded reaction time task that provided a comparison of activity between error vs. correct responses. Analyses focused on time-frequency power, frequency band-specific inter-electrode connectivity, and within-subject cross-trial correlations between EEG activity and reaction time. Time-frequency power analyses showed similar patterns of midfrontal delta-theta power for errors compared to correct responses across all spatial transformations. Beamforming additionally revealed error-related anterior and lateral prefrontal beta-band activity. Within-subject brain-behavior correlations showed similar patterns of results across the spatial transformations, with the correlations being the weakest after beamforming. The most striking difference among the spatial transformations was seen in connectivity analyses: linked earlobe reference produced weak inter-site connectivity that was attributable to volume conduction (zero phase lag), while the average reference and Laplacian produced more interpretable connectivity results. Beamforming did not reveal any significant condition modulations of connectivity. Overall, these analyses show that some findings are robust to spatial transformations, while other findings, particularly those involving cross-trial analyses or connectivity, are more sensitive and may depend on the use of appropriate spatial transformations. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. What are incident reports telling us? A comparative study at two Australian hospitals of medication errors identified at audit, detected by staff and reported to an incident system.

    Science.gov (United States)

    Westbrook, Johanna I; Li, Ling; Lehnbom, Elin C; Baysari, Melissa T; Braithwaite, Jeffrey; Burke, Rosemary; Conn, Chris; Day, Richard O

    2015-02-01

    To (i) compare medication errors identified at audit and observation with medication incident reports; (ii) identify differences between two hospitals in incident report frequency and medication error rates; (iii) identify prescribing error detection rates by staff. Audit of 3291 patient records at two hospitals to identify prescribing errors and evidence of their detection by staff. Medication administration errors were identified from a direct observational study of 180 nurses administering 7451 medications. Severity of errors was classified. Those likely to lead to patient harm were categorized as 'clinically important'. Two major academic teaching hospitals in Sydney, Australia. Rates of medication errors identified from audit and from direct observation were compared with reported medication incident reports. A total of 12 567 prescribing errors were identified at audit. Of these 1.2/1000 errors (95% CI: 0.6-1.8) had incident reports. Clinically important prescribing errors (n = 539) were detected by staff at a rate of 218.9/1000 (95% CI: 184.0-253.8), but only 13.0/1000 (95% CI: 3.4-22.5) were reported. 78.1% (n = 421) of clinically important prescribing errors were not detected. A total of 2043 drug administrations (27.4%; 95% CI: 26.4-28.4%) contained ≥ 1 errors; none had an incident report. Hospital A had a higher frequency of incident reports than Hospital B, but a lower rate of errors at audit. Prescribing errors with the potential to cause harm frequently go undetected. Reported incidents do not reflect the profile of medication errors which occur in hospitals or the underlying rates. This demonstrates the inaccuracy of using incident frequency to compare patient risk or quality performance within or across hospitals. New approaches including data mining of electronic clinical information systems are required to support more effective medication error detection and mitigation. © The Author 2015. Published by Oxford University Press in association

  17. Exploring behavioural determinants relating to health professional reporting of medication errors: a qualitative study using the Theoretical Domains Framework.

    Science.gov (United States)

    Alqubaisi, Mai; Tonna, Antonella; Strath, Alison; Stewart, Derek

    2016-07-01

    Effective and efficient medication reporting processes are essential in promoting patient safety. Few qualitative studies have explored reporting of medication errors by health professionals, and none have made reference to behavioural theories. The objective was to describe and understand the behavioural determinants of health professional reporting of medication errors in the United Arab Emirates (UAE). This was a qualitative study comprising face-to-face, semi-structured interviews within three major medical/surgical hospitals of Abu Dhabi, the UAE. Health professionals were sampled purposively in strata of profession and years of experience. The semi-structured interview schedule focused on behavioural determinants around medication error reporting, facilitators, barriers and experiences. The Theoretical Domains Framework (TDF; a framework of theories of behaviour change) was used as a coding framework. Ethical approval was obtained from a UK university and all participating hospital ethics committees. Data saturation was achieved after interviewing ten nurses, ten pharmacists and nine physicians. Whilst it appeared that patient safety and organisational improvement goals and intentions were behavioural determinants which facilitated reporting, there were key determinants which deterred reporting. These included the beliefs of the consequences of reporting (lack of any feedback following reporting and impacting professional reputation, relationships and career progression), emotions (fear and worry) and issues related to the environmental context (time taken to report). These key behavioural determinants which negatively impact error reporting can facilitate the development of an intervention, centring on organisational safety and reporting culture, to enhance reporting effectiveness and efficiency.

  18. Mixtures of Berkson and classical covariate measurement error in the linear mixed model: Bias analysis and application to a study on ultrafine particles.

    Science.gov (United States)

    Deffner, Veronika; Küchenhoff, Helmut; Breitner, Susanne; Schneider, Alexandra; Cyrys, Josef; Peters, Annette

    2018-03-13

    The ultrafine particle measurements in the Augsburger Umweltstudie, a panel study conducted in Augsburg, Germany, exhibit measurement error from various sources. Measurements of mobile devices show classical possibly individual-specific measurement error; Berkson-type error, which may also vary individually, occurs, if measurements of fixed monitoring stations are used. The combination of fixed site and individual exposure measurements results in a mixture of the two error types. We extended existing bias analysis approaches to linear mixed models with a complex error structure including individual-specific error components, autocorrelated errors, and a mixture of classical and Berkson error. Theoretical considerations and simulation results show, that autocorrelation may severely change the attenuation of the effect estimations. Furthermore, unbalanced designs and the inclusion of confounding variables influence the degree of attenuation. Bias correction with the method of moments using data with mixture measurement error partially yielded better results compared to the usage of incomplete data with classical error. Confidence intervals (CIs) based on the delta method achieved better coverage probabilities than those based on Bootstrap samples. Moreover, we present the application of these new methods to heart rate measurements within the Augsburger Umweltstudie: the corrected effect estimates were slightly higher than their naive equivalents. The substantial measurement error of ultrafine particle measurements has little impact on the results. The developed methodology is generally applicable to longitudinal data with measurement error. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Learning from Errors

    Science.gov (United States)

    Metcalfe, Janet

    2017-01-01

    Although error avoidance during learning appears to be the rule in American classrooms, laboratory studies suggest that it may be a counterproductive strategy, at least for neurologically typical students. Experimental investigations indicate that errorful learning followed by corrective feedback is beneficial to learning. Interestingly, the…

  20. The Applicability of Standard Error of Measurement and Minimal Detectable Change to Motor Learning Research-A Behavioral Study.

    Science.gov (United States)

    Furlan, Leonardo; Sterr, Annette

    2018-01-01

    Motor learning studies face the challenge of differentiating between real changes in performance and random measurement error. While the traditional p -value-based analyses of difference (e.g., t -tests, ANOVAs) provide information on the statistical significance of a reported change in performance scores, they do not inform as to the likely cause or origin of that change, that is, the contribution of both real modifications in performance and random measurement error to the reported change. One way of differentiating between real change and random measurement error is through the utilization of the statistics of standard error of measurement (SEM) and minimal detectable change (MDC). SEM is estimated from the standard deviation of a sample of scores at baseline and a test-retest reliability index of the measurement instrument or test employed. MDC, in turn, is estimated from SEM and a degree of confidence, usually 95%. The MDC value might be regarded as the minimum amount of change that needs to be observed for it to be considered a real change, or a change to which the contribution of real modifications in performance is likely to be greater than that of random measurement error. A computer-based motor task was designed to illustrate the applicability of SEM and MDC to motor learning research. Two studies were conducted with healthy participants. Study 1 assessed the test-retest reliability of the task and Study 2 consisted in a typical motor learning study, where participants practiced the task for five consecutive days. In Study 2, the data were analyzed with a traditional p -value-based analysis of difference (ANOVA) and also with SEM and MDC. The findings showed good test-retest reliability for the task and that the p -value-based analysis alone identified statistically significant improvements in performance over time even when the observed changes could in fact have been smaller than the MDC and thereby caused mostly by random measurement error, as opposed

  1. Power and sample size calculations in the presence of phenotype errors for case/control genetic association studies

    Directory of Open Access Journals (Sweden)

    Finch Stephen J

    2005-04-01

    Full Text Available Abstract Background Phenotype error causes reduction in power to detect genetic association. We present a quantification of phenotype error, also known as diagnostic error, on power and sample size calculations for case-control genetic association studies between a marker locus and a disease phenotype. We consider the classic Pearson chi-square test for independence as our test of genetic association. To determine asymptotic power analytically, we compute the distribution's non-centrality parameter, which is a function of the case and control sample sizes, genotype frequencies, disease prevalence, and phenotype misclassification probabilities. We derive the non-centrality parameter in the presence of phenotype errors and equivalent formulas for misclassification cost (the percentage increase in minimum sample size needed to maintain constant asymptotic power at a fixed significance level for each percentage increase in a given misclassification parameter. We use a linear Taylor Series approximation for the cost of phenotype misclassification to determine lower bounds for the relative costs of misclassifying a true affected (respectively, unaffected as a control (respectively, case. Power is verified by computer simulation. Results Our major findings are that: (i the median absolute difference between analytic power with our method and simulation power was 0.001 and the absolute difference was no larger than 0.011; (ii as the disease prevalence approaches 0, the cost of misclassifying a unaffected as a case becomes infinitely large while the cost of misclassifying an affected as a control approaches 0. Conclusion Our work enables researchers to specifically quantify power loss and minimum sample size requirements in the presence of phenotype errors, thereby allowing for more realistic study design. For most diseases of current interest, verifying that cases are correctly classified is of paramount importance.

  2. Ergonomic study of biorhythm effect on the 62 occurrence of human errors and accidents in automobile manufacturing industry

    OpenAIRE

    2012-01-01

    Background and Aim: According to the biorhythm theory when the phase shift from positive to negative and vice versa people experience a critical an unstable day that prone them to error and accident. The purpose of this study is to determine this relationship in one of the automobile manufacturing industry. . Materials and Methods: At first 1280 person incident entered the study was reviewed and then the critical days of each biological cycle was determined using the software Easy Biorh...

  3. A study of redundancy management strategy for tetrad strap-down inertial systems. [error detection codes

    Science.gov (United States)

    Hruby, R. J.; Bjorkman, W. S.; Schmidt, S. F.; Carestia, R. A.

    1979-01-01

    Algorithms were developed that attempt to identify which sensor in a tetrad configuration has experienced a step failure. An algorithm is also described that provides a measure of the confidence with which the correct identification was made. Experimental results are presented from real-time tests conducted on a three-axis motion facility utilizing an ortho-skew tetrad strapdown inertial sensor package. The effects of prediction errors and of quantization on correct failure identification are discussed as well as an algorithm for detecting second failures through prediction.

  4. Development of a simulation program to study error propagation in the reprocessing input accountancy measurements

    International Nuclear Information System (INIS)

    Sanfilippo, L.

    1987-01-01

    A physical model and a computer program have been developed to simulate all the measurement operations involved with the Isotopic Dilution Analysis technique currently applied in the Volume - Concentration method for the Reprocessing Input Accountancy, together with their errors or uncertainties. The simulator is apt to easily solve a number of problems related to the measurement sctivities of the plant operator and the inspector. The program, written in Fortran 77, is based on a particular Montecarlo technique named ''Random Sampling''; a full description of the code is reported

  5. A feasibility study of mutual information based setup error estimation for radiotherapy

    International Nuclear Information System (INIS)

    Kim, Jeongtae; Fessler, Jeffrey A.; Lam, Kwok L.; Balter, James M.; Haken, Randall K. ten

    2001-01-01

    We have investigated a fully automatic setup error estimation method that aligns DRRs (digitally reconstructed radiographs) from a three-dimensional planning computed tomography image onto two-dimensional radiographs that are acquired in a treatment room. We have chosen a MI (mutual information)-based image registration method, hoping for robustness to intensity differences between the DRRs and the radiographs. The MI-based estimator is fully automatic since it is based on the image intensity values without segmentation. Using 10 repeated scans of an anthropomorphic chest phantom in one position and two single scans in two different positions, we evaluated the performance of the proposed method and a correlation-based method against the setup error determined by fiducial marker-based method. The mean differences between the proposed method and the fiducial marker-based method were smaller than 1 mm for translational parameters and 0.8 degree for rotational parameters. The standard deviations of estimates from the proposed method due to detector noise were smaller than 0.3 mm and 0.07 degree for the translational parameters and rotational parameters, respectively

  6. ERRORS MEASUREMENT OF INTERPOLATION METHODS FOR GEOID MODELS: STUDY CASE IN THE BRAZILIAN REGION

    Directory of Open Access Journals (Sweden)

    Daniel Arana

    Full Text Available Abstract: The geoid is an equipotential surface regarded as the altimetric reference for geodetic surveys and it therefore, has several practical applications for engineers. In recent decades the geodetic community has concentrated efforts on the development of highly accurate geoid models through modern techniques. These models are supplied through regular grids which users need to make interpolations. Yet, little information can be obtained regarding the most appropriate interpolation method to extract information from the regular grid of geoidal models. The use of an interpolator that does not represent the geoid surface appropriately can impair the quality of geoid undulations and consequently the height transformation. This work aims to quantify the magnitude of error that comes from a regular mesh of geoid models. The analysis consisted of performing a comparison between the interpolation of the MAPGEO2015 program and three interpolation methods: bilinear, cubic spline and neural networks Radial Basis Function. As a result of the experiments, it was concluded that 2.5 cm of the 18 cm error of the MAPGEO2015 validation is caused by the use of interpolations in the 5'x5' grid.

  7. Limit of detection in the presence of instrumental and non-instrumental errors: study of the possible sources of error and application to the analysis of 41 elements at trace levels by inductively coupled plasma-mass spectrometry technique

    International Nuclear Information System (INIS)

    Badocco, Denis; Lavagnini, Irma; Mondin, Andrea; Tapparo, Andrea; Pastore, Paolo

    2015-01-01

    In this paper the detection limit was estimated when signals were affected by two error contributions, namely instrumental errors and operational-non-instrumental errors. The detection limit was theoretically obtained following the hypothesis testing schema implemented with the calibration curve methodology. The experimental calibration design was based on J standards measured I times with non-instrumental errors affecting each standard systematically but randomly among the J levels. A two-component variance regression was performed to determine the calibration curve and to define the detection limit in these conditions. The detection limit values obtained from the calibration at trace levels of 41 elements by ICP-MS resulted larger than those obtainable from a one component variance regression. The role of the reagent impurities on the instrumental errors was ascertained and taken into account. Environmental pollution was studied as source of non-instrumental errors. The environmental pollution role was evaluated by Principal Component Analysis technique (PCA) applied to a series of nine calibrations performed in fourteen months. The influence of the seasonality of the environmental pollution on the detection limit was evidenced for many elements usually present in the urban air particulate. The obtained results clearly indicated the need of using the two-component variance regression approach for the calibration of all the elements usually present in the environment at significant concentration levels. - Highlights: • Limit of detection was obtained considering a two variance component regression. • Calibration data may be affected by instrumental and operational conditions errors. • Calibration model was applied to determine 41 elements at trace level by ICP-MS. • Non instrumental errors were evidenced by PCA analysis

  8. Methods for Estimation of Radiation Risk in Epidemiological Studies Accounting for Classical and Berkson Errors in Doses

    KAUST Repository

    Kukush, Alexander

    2011-01-16

    With a binary response Y, the dose-response model under consideration is logistic in flavor with pr(Y=1 | D) = R (1+R)(-1), R = λ(0) + EAR D, where λ(0) is the baseline incidence rate and EAR is the excess absolute risk per gray. The calculated thyroid dose of a person i is expressed as Dimes=fiQi(mes)/Mi(mes). Here, Qi(mes) is the measured content of radioiodine in the thyroid gland of person i at time t(mes), Mi(mes) is the estimate of the thyroid mass, and f(i) is the normalizing multiplier. The Q(i) and M(i) are measured with multiplicative errors Vi(Q) and ViM, so that Qi(mes)=Qi(tr)Vi(Q) (this is classical measurement error model) and Mi(tr)=Mi(mes)Vi(M) (this is Berkson measurement error model). Here, Qi(tr) is the true content of radioactivity in the thyroid gland, and Mi(tr) is the true value of the thyroid mass. The error in f(i) is much smaller than the errors in ( Qi(mes), Mi(mes)) and ignored in the analysis. By means of Parametric Full Maximum Likelihood and Regression Calibration (under the assumption that the data set of true doses has lognormal distribution), Nonparametric Full Maximum Likelihood, Nonparametric Regression Calibration, and by properly tuned SIMEX method we study the influence of measurement errors in thyroid dose on the estimates of λ(0) and EAR. The simulation study is presented based on a real sample from the epidemiological studies. The doses were reconstructed in the framework of the Ukrainian-American project on the investigation of Post-Chernobyl thyroid cancers in Ukraine, and the underlying subpolulation was artificially enlarged in order to increase the statistical power. The true risk parameters were given by the values to earlier epidemiological studies, and then the binary response was simulated according to the dose-response model.

  9. Methods for estimation of radiation risk in epidemiological studies accounting for classical and Berkson errors in doses.

    Science.gov (United States)

    Kukush, Alexander; Shklyar, Sergiy; Masiuk, Sergii; Likhtarov, Illya; Kovgan, Lina; Carroll, Raymond J; Bouville, Andre

    2011-02-16

    With a binary response Y, the dose-response model under consideration is logistic in flavor with pr(Y=1 | D) = R (1+R)(-1), R = λ(0) + EAR D, where λ(0) is the baseline incidence rate and EAR is the excess absolute risk per gray. The calculated thyroid dose of a person i is expressed as Dimes=fiQi(mes)/Mi(mes). Here, Qi(mes) is the measured content of radioiodine in the thyroid gland of person i at time t(mes), Mi(mes) is the estimate of the thyroid mass, and f(i) is the normalizing multiplier. The Q(i) and M(i) are measured with multiplicative errors Vi(Q) and ViM, so that Qi(mes)=Qi(tr)Vi(Q) (this is classical measurement error model) and Mi(tr)=Mi(mes)Vi(M) (this is Berkson measurement error model). Here, Qi(tr) is the true content of radioactivity in the thyroid gland, and Mi(tr) is the true value of the thyroid mass. The error in f(i) is much smaller than the errors in ( Qi(mes), Mi(mes)) and ignored in the analysis. By means of Parametric Full Maximum Likelihood and Regression Calibration (under the assumption that the data set of true doses has lognormal distribution), Nonparametric Full Maximum Likelihood, Nonparametric Regression Calibration, and by properly tuned SIMEX method we study the influence of measurement errors in thyroid dose on the estimates of λ(0) and EAR. The simulation study is presented based on a real sample from the epidemiological studies. The doses were reconstructed in the framework of the Ukrainian-American project on the investigation of Post-Chernobyl thyroid cancers in Ukraine, and the underlying subpolulation was artificially enlarged in order to increase the statistical power. The true risk parameters were given by the values to earlier epidemiological studies, and then the binary response was simulated according to the dose-response model.

  10. Optical design and studies of a tiled single grating pulse compressor for enhanced parametric space and compensation of tiling errors

    Science.gov (United States)

    Daiya, D.; Patidar, R. K.; Sharma, J.; Joshi, A. S.; Naik, P. A.; Gupta, P. D.

    2017-04-01

    A new optical design of tiled single grating pulse compressor has been proposed, set-up and studied. The parametric space, i.e. the laser beam diameters that can be accommodated in the pulse compressor for the given range of compression lengths, has been calculated and shown to have up to two fold enhancement in comparison to our earlier proposed optical designs. The new optical design of the tiled single grating pulse compressor has an additional advantage of self compensation of various tiling errors like longitudinal and lateral piston, tip and groove density mismatch, compared to the earlier designs. Experiments have been carried out for temporal compression of 650 ps positively chirped laser pulses, at central wavelength 1054 nm, down to 235 fs in the tiled grating pulse compressor set up with the proposed design. Further, far field studies have been performed to show the desired compensation of the tiling errors takes place in the new compressor.

  11. Assessing type I error and power of multistate Markov models for panel data-A simulation study

    OpenAIRE

    Cassarly, Christy; Martin, Renee’ H.; Chimowitz, Marc; Peña, Edsel A.; Ramakrishnan, Viswanathan; Palesch, Yuko Y.

    2016-01-01

    Ordinal outcomes collected at multiple follow-up visits are common in clinical trials. Sometimes, one visit is chosen for the primary analysis and the scale is dichotomized amounting to loss of information. Multistate Markov models describe how a process moves between states over time. Here, simulation studies are performed to investigate the type I error and power characteristics of multistate Markov models for panel data with limited non-adjacent state transitions. The results suggest that ...

  12. Estimation of glucose kinetics in fetal-maternal studies: Potential errors, solutions, and limitations

    International Nuclear Information System (INIS)

    Menon, R.K.; Bloch, C.A.; Sperling, M.A.

    1990-01-01

    We investigated whether errors occur in the estimation of ovine maternal-fetal glucose (Glc) kinetics using the isotope dilution technique when the Glc pool is rapidly expanded by exogenous (protocol A) or endogenous (protocol C) Glc entry and sought possible solutions (protocol B). In protocol A (n = 8), after attaining steady-state Glc specific activity (SA) by [U-14C]glucose (period 1), infusion of Glc (period 2) predictably decreased Glc SA, whereas. [U-14C]glucose concentration unexpectedly rose from 7,208 +/- 367 (means +/- SE) in period 1 to 8,558 +/- 308 disintegrations/min (dpm) per ml in period 2 (P less than 0.01). Fetal endogenous Glc production (EGP) was negligible during period 1 (0.44 +/- 1.0), but yielded a physiologically impossible negative value of -2.1 +/- 0.72 mg.kg-1.min-1 during period 2. When the fall in Glc SA during Glc infusion was prevented by addition of [U-14C]glucose admixed with the exogenous Glc (protocol B; n = 7), EGP was no longer negative. In protocol C (n = 6), sequential infusions of four increasing doses of epinephrine serially decreased SA, whereas tracer Glc increased from 7,483 +/- 608 to 11,525 +/- 992 dpm/ml plasma (P less than 0.05), imposing an obligatory underestimation of EGP. Thus a tracer mixing problem leads to erroneous estimations of fetal Glc utilization and Glc production via the three-compartment model in sheep when the Glc pool is expanded exogenously or endogenously. These errors can be minimized by maintaining the Glc SA relatively constant

  13. Report from LHC MDs 1391 and 1483: Tests of new methods for study of nonlinear errors in the LHC experimental insertions

    CERN Document Server

    Maclean, Ewen Hamish; Fuchsberger, Kajetan; Giovannozzi, Massimo; Persson, Tobias Hakan Bjorn; Tomas Garcia, Rogelio; CERN. Geneva. ATS Department

    2017-01-01

    Nonlinear errors in experimental insertions can pose a significant challenge to the operability of low-β∗ colliders. Previously such errors in the LHC have been studied via their feed-down to tune and coupling under the influence of the nominal crossing angle bumps. This method has proved useful in validating various components of the magnetic model. To understand and correct those errors where significant discrepancies exist with the magnetic model however, will require further development of this technique, in addition to the application of novel methods. In 2016 studies were performed to test new methods for the study of the IR-nonlinear errors.

  14. Education influences the association between genetic variants and refractive error: a meta-analysis of five Singapore studies

    Science.gov (United States)

    Fan, Qiao; Wojciechowski, Robert; Kamran Ikram, M.; Cheng, Ching-Yu; Chen, Peng; Zhou, Xin; Pan, Chen-Wei; Khor, Chiea-Chuen; Tai, E-Shyong; Aung, Tin; Wong, Tien-Yin; Teo, Yik-Ying; Saw, Seang-Mei

    2014-01-01

    Refractive error is a complex ocular trait governed by both genetic and environmental factors and possibly their interplay. Thus far, data on the interaction between genetic variants and environmental risk factors for refractive errors are largely lacking. By using findings from recent genome-wide association studies, we investigated whether the main environmental factor, education, modifies the effect of 40 single nucleotide polymorphisms on refractive error among 8461 adults from five studies including ethnic Chinese, Malay and Indian residents of Singapore. Three genetic loci SHISA6-DNAH9, GJD2 and ZMAT4-SFRP1 exhibited a strong association with myopic refractive error in individuals with higher secondary or university education (SHISA6-DNAH9: rs2969180 A allele, β = −0.33 D, P = 3.6 × 10–6; GJD2: rs524952 A allele, β = −0.31 D, P = 1.68 × 10−5; ZMAT4-SFRP1: rs2137277 A allele, β = −0.47 D, P = 1.68 × 10−4), whereas the association at these loci was non-significant or of borderline significance in those with lower secondary education or below (P for interaction: 3.82 × 10−3–4.78 × 10−4). The evidence for interaction was strengthened when combining the genetic effects of these three loci (P for interaction = 4.40 × 10−8), and significant interactions with education were also observed for axial length and myopia. Our study shows that low level of education may attenuate the effect of risk alleles on myopia. These findings further underline the role of gene–environment interactions in the pathophysiology of myopia. PMID:24014484

  15. The preliminary study on the inductory signal triggering the error-prone DNA repair function in mammalian cells

    International Nuclear Information System (INIS)

    Su Zaozhong; Luo Zuyu

    1989-01-01

    The nature of the signal triggering error-prone DNA repair function in mammalian cells was studied from two notions: (1) Does the inducing signal result from the direct hitting the cellular targets by DNA-damaging agents? (2) Is inhibition of DNA replication a prerequisite condition for the triggering effect? Thus, the ultraviolet (UV)-irradiated exogenous DNAs were introduced into human and rat cells by transfection. The results showed that this transfection was able to induce the error-prone repair as efficient as direct UV-irradiation to cells. Moreover, the two inductory treaetments expressed similar kinetics and dose-responses. No matter whether the introduced DNAs initiated replication, they exhibited the incuctory activity. Therefore, it can be considered that DNA lesions itself, not the direct interaction of DNA-damaging agents with specific cellular targets, serve as a triggering signal for the inductory process. Inhibition of DNA replication is not a prerequisite for the inductory signal

  16. The analysis of human error as causes in the maintenance of machines: a case study in mining companies

    Directory of Open Access Journals (Sweden)

    Kovacevic, Srdja

    2016-12-01

    Full Text Available This paper describes the two-step method used to analyse the factors and aspects influencing human error during the maintenance of mining machines. The first step is the cause-effect analysis, supported by brainstorming, where five factors and 21 aspects are identified. During the second step, the group fuzzy analytic hierarchy process is used to rank the identified factors and aspects. A case study is done on mining companies in Serbia. The key aspects are ranked according to an analysis that included experts who assess risks in mining companies (a maintenance engineer, a technologist, an ergonomist, a psychologist, and an organisational scientist. Failure to follow technical maintenance instructions, poor organisation of the training process, inadequate diagnostic equipment, and a lack of understanding of the work process are identified as the most important causes of human error.

  17. A Benchmark Study on Error Assessment and Quality Control of CCS Reads Derived from the PacBio RS.

    Science.gov (United States)

    Jiao, Xiaoli; Zheng, Xin; Ma, Liang; Kutty, Geetha; Gogineni, Emile; Sun, Qiang; Sherman, Brad T; Hu, Xiaojun; Jones, Kristine; Raley, Castle; Tran, Bao; Munroe, David J; Stephens, Robert; Liang, Dun; Imamichi, Tomozumi; Kovacs, Joseph A; Lempicki, Richard A; Huang, Da Wei

    2013-07-31

    PacBio RS, a newly emerging third-generation DNA sequencing platform, is based on a real-time, single-molecule, nano-nitch sequencing technology that can generate very long reads (up to 20-kb) in contrast to the shorter reads produced by the first and second generation sequencing technologies. As a new platform, it is important to assess the sequencing error rate, as well as the quality control (QC) parameters associated with the PacBio sequence data. In this study, a mixture of 10 prior known, closely related DNA amplicons were sequenced using the PacBio RS sequencing platform. After aligning Circular Consensus Sequence (CCS) reads derived from the above sequencing experiment to the known reference sequences, we found that the median error rate was 2.5% without read QC, and improved to 1.3% with an SVM based multi-parameter QC method. In addition, a De Novo assembly was used as a downstream application to evaluate the effects of different QC approaches. This benchmark study indicates that even though CCS reads are post error-corrected it is still necessary to perform appropriate QC on CCS reads in order to produce successful downstream bioinformatics analytical results.

  18. Establishing error management process for power plants. A study on entire picture of the process and introduction stages

    International Nuclear Information System (INIS)

    Hirotsu, Yuko; Fujimoto, Junzo; Sugihara, Yoshikuni; Takeda, Daisuke

    2009-01-01

    The purpose of this study is to establish a management process for a power plant to positively find out actual and/or potential problems that may possibility cause a serious human factor event, and to take effective measures. Firstly, detail steps for error management process utilizing human factor event data has been examined through an application at a plant. Secondly, basic steps for evaluating the degree of execution, enhancement and usefulness of each human performance activity and for identifying unsafe acts and uneasy human performance states were established based on literature searching and our experiences on plant evaluation. Finally, an entire picture of error management process was proposed by unifying the steps studied above. In addition, as stages for introducing and establishing the above proposed error management process into a power plant, a basic idea of supplementing an insufficient part of the process with a phased approach after comparing the above proposed management process and the existing human performance activities at the plant was introduced. (author)

  19. A simulation study to quantify the impacts of exposure measurement error on air pollution health risk estimates in copollutant time-series models.

    Science.gov (United States)

    Dionisio, Kathie L; Chang, Howard H; Baxter, Lisa K

    2016-11-25

    Exposure measurement error in copollutant epidemiologic models has the potential to introduce bias in relative risk (RR) estimates. A simulation study was conducted using empirical data to quantify the impact of correlated measurement errors in time-series analyses of air pollution and health. ZIP-code level estimates of exposure for six pollutants (CO, NO x , EC, PM 2.5 , SO 4 , O 3 ) from 1999 to 2002 in the Atlanta metropolitan area were used to calculate spatial, population (i.e. ambient versus personal), and total exposure measurement error. Empirically determined covariance of pollutant concentration pairs and the associated measurement errors were used to simulate true exposure (exposure without error) from observed exposure. Daily emergency department visits for respiratory diseases were simulated using a Poisson time-series model with a main pollutant RR = 1.05 per interquartile range, and a null association for the copollutant (RR = 1). Monte Carlo experiments were used to evaluate the impacts of correlated exposure errors of different copollutant pairs. Substantial attenuation of RRs due to exposure error was evident in nearly all copollutant pairs studied, ranging from 10 to 40% attenuation for spatial error, 3-85% for population error, and 31-85% for total error. When CO, NO x or EC is the main pollutant, we demonstrated the possibility of false positives, specifically identifying significant, positive associations for copollutants based on the estimated type I error rate. The impact of exposure error must be considered when interpreting results of copollutant epidemiologic models, due to the possibility of attenuation of main pollutant RRs and the increased probability of false positives when measurement error is present.

  20. Optimal classifier selection and negative bias in error rate estimation: an empirical study on high-dimensional prediction

    Directory of Open Access Journals (Sweden)

    Boulesteix Anne-Laure

    2009-12-01

    Full Text Available Abstract Background In biometric practice, researchers often apply a large number of different methods in a "trial-and-error" strategy to get as much as possible out of their data and, due to publication pressure or pressure from the consulting customer, present only the most favorable results. This strategy may induce a substantial optimistic bias in prediction error estimation, which is quantitatively assessed in the present manuscript. The focus of our work is on class prediction based on high-dimensional data (e.g. microarray data, since such analyses are particularly exposed to this kind of bias. Methods In our study we consider a total of 124 variants of classifiers (possibly including variable selection or tuning steps within a cross-validation evaluation scheme. The classifiers are applied to original and modified real microarray data sets, some of which are obtained by randomly permuting the class labels to mimic non-informative predictors while preserving their correlation structure. Results We assess the minimal misclassification rate over the different variants of classifiers in order to quantify the bias arising when the optimal classifier is selected a posteriori in a data-driven manner. The bias resulting from the parameter tuning (including gene selection parameters as a special case and the bias resulting from the choice of the classification method are examined both separately and jointly. Conclusions The median minimal error rate over the investigated classifiers was as low as 31% and 41% based on permuted uninformative predictors from studies on colon cancer and prostate cancer, respectively. We conclude that the strategy to present only the optimal result is not acceptable because it yields a substantial bias in error rate estimation, and suggest alternative approaches for properly reporting classification accuracy.

  1. Towards more reliable automated multi-dose dispensing: retrospective follow-up study on medication dose errors and product defects.

    Science.gov (United States)

    Palttala, Iida; Heinämäki, Jyrki; Honkanen, Outi; Suominen, Risto; Antikainen, Osmo; Hirvonen, Jouni; Yliruusi, Jouko

    2013-03-01

    To date, little is known on applicability of different types of pharmaceutical dosage forms in an automated high-speed multi-dose dispensing process. The purpose of the present study was to identify and further investigate various process-induced and/or product-related limitations associated with multi-dose dispensing process. The rates of product defects and dose dispensing errors in automated multi-dose dispensing were retrospectively investigated during a 6-months follow-up period. The study was based on the analysis of process data of totally nine automated high-speed multi-dose dispensing systems. Special attention was paid to the dependence of multi-dose dispensing errors/product defects and pharmaceutical tablet properties (such as shape, dimensions, weight, scored lines, coatings, etc.) to profile the most suitable forms of tablets for automated dose dispensing systems. The relationship between the risk of errors in dose dispensing and tablet characteristics were visualized by creating a principal component analysis (PCA) model for the outcome of dispensed tablets. The two most common process-induced failures identified in the multi-dose dispensing are predisposal of tablet defects and unexpected product transitions in the medication cassette (dose dispensing error). The tablet defects are product-dependent failures, while the tablet transitions are dependent on automated multi-dose dispensing systems used. The occurrence of tablet defects is approximately twice as common as tablet transitions. Optimal tablet preparation for the high-speed multi-dose dispensing would be a round-shaped, relatively small/middle-sized, film-coated tablet without any scored line. Commercial tablet products can be profiled and classified based on their suitability to a high-speed multi-dose dispensing process.

  2. Comparative study of anatomical normalization errors in SPM and 3D-SSP using digital brain phantom.

    Science.gov (United States)

    Onishi, Hideo; Matsutake, Yuki; Kawashima, Hiroki; Matsutomo, Norikazu; Amijima, Hizuru

    2011-01-01

    In single photon emission computed tomography (SPECT) cerebral blood flow studies, two major algorithms are widely used statistical parametric mapping (SPM) and three-dimensional stereotactic surface projections (3D-SSP). The aim of this study is to compare an SPM algorithm-based easy Z score imaging system (eZIS) and a 3D-SSP system in the errors of anatomical standardization using 3D-digital brain phantom images. We developed a 3D-brain digital phantom based on MR images to simulate the effects of head tilt, perfusion defective region size, and count value reduction rate on the SPECT images. This digital phantom was used to compare the errors of anatomical standardization by the eZIS and the 3D-SSP algorithms. While the eZIS allowed accurate standardization of the images of the phantom simulating a head in rotation, lateroflexion, anteflexion, or retroflexion without angle dependency, the standardization by 3D-SSP was not accurate enough at approximately 25° or more head tilt. When the simulated head contained perfusion defective regions, one of the 3D-SSP images showed an error of 6.9% from the true value. Meanwhile, one of the eZIS images showed an error as large as 63.4%, revealing a significant underestimation. When required to evaluate regions with decreased perfusion due to such causes as hemodynamic cerebral ischemia, the 3D-SSP is desirable. In a statistical image analysis, we must reconfirm the image after anatomical standardization by all means.

  3. Comparative study of anatomical normalization errors in SPM and 3D-SSP using digital brain phantom

    International Nuclear Information System (INIS)

    Onishi, Hideo; Matsutomo, Norikazu; Matsutake, Yuki; Kawashima, Hiroki; Amijima, Hizuru

    2011-01-01

    In single photon emission computed tomography (SPECT) cerebral blood flow studies, two major algorithms are widely used statistical parametric mapping (SPM) and three-dimensional stereotactic surface projections (3D-SSP). The aim of this study is to compare an SPM algorithm-based easy Z score imaging system (eZIS) and a 3D-SSP system in the errors of anatomical standardization using 3D-digital brain phantom images. We developed a 3D-brain digital phantom based on MR images to simulate the effects of head tilt, perfusion defective region size, and count value reduction rate on the SPECT images. This digital phantom was used to compare the errors of anatomical standardization by the eZIS and the 3D-SSP algorithms. While the eZIS allowed accurate standardization of the images of the phantom simulating a head in rotation, lateroflexion, anteflexion, or retroflexion without angle dependency, the standardization by 3D-SSP was not accurate enough at approximately 25 deg or more head tilt. When the simulated head contained perfusion defective regions, one of the 3D-SSP images showed an error of 6.9% from the true value. Meanwhile, one of the eZIS images showed an error as large as 63.4%, revealing a significant underestimation. When required to evaluate regions with decreased perfusion due to such causes as hemodynamic cerebral ischemia, the 3D-SSP is desirable. In a statistical image analysis, we must reconfirm the image after anatomical standardization by all means. (author)

  4. Uncorrected refractive errors.

    Science.gov (United States)

    Naidoo, Kovin S; Jaggernath, Jyoti

    2012-01-01

    Global estimates indicate that more than 2.3 billion people in the world suffer from poor vision due to refractive error; of which 670 million people are considered visually impaired because they do not have access to corrective treatment. Refractive errors, if uncorrected, results in an impaired quality of life for millions of people worldwide, irrespective of their age, sex and ethnicity. Over the past decade, a series of studies using a survey methodology, referred to as Refractive Error Study in Children (RESC), were performed in populations with different ethnic origins and cultural settings. These studies confirmed that the prevalence of uncorrected refractive errors is considerably high for children in low-and-middle-income countries. Furthermore, uncorrected refractive error has been noted to have extensive social and economic impacts, such as limiting educational and employment opportunities of economically active persons, healthy individuals and communities. The key public health challenges presented by uncorrected refractive errors, the leading cause of vision impairment across the world, require urgent attention. To address these issues, it is critical to focus on the development of human resources and sustainable methods of service delivery. This paper discusses three core pillars to addressing the challenges posed by uncorrected refractive errors: Human Resource (HR) Development, Service Development and Social Entrepreneurship.

  5. Uncorrected refractive errors

    Directory of Open Access Journals (Sweden)

    Kovin S Naidoo

    2012-01-01

    Full Text Available Global estimates indicate that more than 2.3 billion people in the world suffer from poor vision due to refractive error; of which 670 million people are considered visually impaired because they do not have access to corrective treatment. Refractive errors, if uncorrected, results in an impaired quality of life for millions of people worldwide, irrespective of their age, sex and ethnicity. Over the past decade, a series of studies using a survey methodology, referred to as Refractive Error Study in Children (RESC, were performed in populations with different ethnic origins and cultural settings. These studies confirmed that the prevalence of uncorrected refractive errors is considerably high for children in low-and-middle-income countries. Furthermore, uncorrected refractive error has been noted to have extensive social and economic impacts, such as limiting educational and employment opportunities of economically active persons, healthy individuals and communities. The key public health challenges presented by uncorrected refractive errors, the leading cause of vision impairment across the world, require urgent attention. To address these issues, it is critical to focus on the development of human resources and sustainable methods of service delivery. This paper discusses three core pillars to addressing the challenges posed by uncorrected refractive errors: Human Resource (HR Development, Service Development and Social Entrepreneurship.

  6. The persistence of error: a study of retracted articles on the Internet and in personal libraries.

    Science.gov (United States)

    Davis, Philip M

    2012-07-01

    To determine the accessibility of retracted articles residing on non-publisher websites and in personal libraries. Searches were performed to locate Internet copies of 1,779 retracted articles identified in MEDLINE, published between 1973 and 2010, excluding the publishers' website. Found copies were classified by article version and location. Mendeley (a bibliographic software) was searched for copies residing in personal libraries. Non-publisher websites provided 321 publicly accessible copies for 289 retracted articles: 304 (95%) copies were the publisher' versions, and 13 (4%) were final manuscripts. PubMed Central had 138 (43%) copies; educational websites 94 (29%); commercial websites 24 (7%); advocacy websites 16 (5%); and institutional repositories 10 (3%). Just 16 [corrected] (5%) full-article views included a retraction statement. Personal Mendeley libraries contained records for 1,340 (75%) retracted articles, shared by 3.4 users, on average. The benefits of decentralized access to scientific articles may come with the cost of promoting incorrect, invalid, or untrustworthy science. Automated methods to deliver status updates to readers may reduce the persistence of error in the scientific literature.

  7. A Recent Revisit Study on the Human Error Events of Nuclear Facilities in Korea

    International Nuclear Information System (INIS)

    Lee, Y.-H.

    2016-01-01

    After Fukushima accident we have launched two new projects in Korea. One is for the development of the countermeasures for human errors in nuclear facilities, and the other is for the safety culture of nuclear power plant itself. There had happened several succeeding events that turned out to be the typical flags of the human and organizational factor issues for the safety of the other socio-technical systems as well as nuclear power plants in Korea. The second safety culture project was an ambitious development to establish an infra system utilising system dynamics, business process modeling and big-data techniques to provide effective and efficient information basis to various interest parties related to the nuclear power plants. However the project has been drastically cancelled last year without any further discussion on the original issues raised before in Korea. It may come not only from the conflicting perspectives among the different approaches to nuclear safety culture but also from the misunderstandings on the human factors for the nuclear safety.

  8. A study on the operator's errors of commission (EOC) in accident scenarios of nuclear power plants: methodology development and application

    International Nuclear Information System (INIS)

    Kim, Jae Whan; Jung, Won Dea; Park, Jin Kyun; Kang, Da Il

    2003-04-01

    As the concern on the operator's inappropriate interventions, the so-called Errors Of Commission (EOCs), that can exacerbate the plant safety has been raised, much of interest in the identification and analysis of EOC events from the risk assessment perspective has been increased. Also, one of the items in need of improvement for the conventional PSA and HRA that consider only the system-demanding human actions is the inclusion of the operator's EOC events into the PSA model. In this study, we propose a methodology for identifying and analysing human errors of commission that might be occurring from the failures in situation assessment and decision making during accident progressions given an initiating event. In order to achieve this goal, the following research items have been performed: Firstly, we analysed the error causes or situations contributed to the occurrence of EOCs in several incidents/accidents of nuclear power plants. Secondly, limitations of the advanced HRAs in treating EOCs were reviewed, and a requirement for a new methodology for analysing EOCs was established. Thirdly, based on these accomplishments a methodology for identifying and analysing EOC events inducible from the failures in situation assessment and decision making was proposed and applied to all the accident sequences of YGN 3 and 4 NPP which resulted in the identification of about 10 EOC situations

  9. Dosimetric impact of systematic MLC positional errors on step and shoot IMRT for prostate cancer: a planning study

    International Nuclear Information System (INIS)

    Ung, N.M.; Wee, L.; Harper, C.S.

    2010-01-01

    Full text: The positional accuracy of multi leaf collimators (MLC) is crucial in ensuring precise delivery of intensity-modulated radiotherapy (IMRT). The aim of this planning study was to investigate the dosimetric impact of systematic MLC errors on step and shoot IMRT of prostate cancer. Twelve MLC leaf banks perturbations were introduced to six prostate IMRT treatment plans to simulate MLC systematic errors. Dose volume histograms (OYHs) were generated for the extraction of dose endpoint parameters. Plans were evaluated in terms of changes to the defined endpoint dose parameters, conformity index (CI) and healthy tissue avoidance (HTA) to planning target volume (PTY), rectum and bladder. Negative perturbations of MLC had been found to produce greater changes to endpoint dose parameters than positive perturbations of MLC (p < 0.05). Negative and positive synchronized MLC perturbations of I mm resulted in median changes of -2.32 and 1.78%, respectively to 095% of PTY whereas asynchronized MLC perturbations of the same direction and magnitude resulted in median changes of 1.18 and 0.90%, respectively. Doses to rectum were generally more sensitive to systematic MLC errors compared to bladder. Synchronized MLC perturbations of I mm resulted in median changes of endpoint dose parameters to both rectum and bladder from about I to 3%. Maximum reduction of -4.44 and -7.29% were recorded for CI and HTA, respectively, due to synchronized MLC perturbation of I mm. In summary, MLC errors resulted in measurable amount of dose changes to PTY and surrounding critical structures in prostate LMRT. (author)

  10. Diagnostic errors in pediatric radiology

    International Nuclear Information System (INIS)

    Taylor, George A.; Voss, Stephan D.; Melvin, Patrice R.; Graham, Dionne A.

    2011-01-01

    Little information is known about the frequency, types and causes of diagnostic errors in imaging children. Our goals were to describe the patterns and potential etiologies of diagnostic error in our subspecialty. We reviewed 265 cases with clinically significant diagnostic errors identified during a 10-year period. Errors were defined as a diagnosis that was delayed, wrong or missed; they were classified as perceptual, cognitive, system-related or unavoidable; and they were evaluated by imaging modality and level of training of the physician involved. We identified 484 specific errors in the 265 cases reviewed (mean:1.8 errors/case). Most discrepancies involved staff (45.5%). Two hundred fifty-eight individual cognitive errors were identified in 151 cases (mean = 1.7 errors/case). Of these, 83 cases (55%) had additional perceptual or system-related errors. One hundred sixty-five perceptual errors were identified in 165 cases. Of these, 68 cases (41%) also had cognitive or system-related errors. Fifty-four system-related errors were identified in 46 cases (mean = 1.2 errors/case) of which all were multi-factorial. Seven cases were unavoidable. Our study defines a taxonomy of diagnostic errors in a large academic pediatric radiology practice and suggests that most are multi-factorial in etiology. Further study is needed to define effective strategies for improvement. (orig.)

  11. Impact of automated dispensing cabinets on medication selection and preparation error rates in an emergency department: a prospective and direct observational before-and-after study.

    Science.gov (United States)

    Fanning, Laura; Jones, Nick; Manias, Elizabeth

    2016-04-01

    The implementation of automated dispensing cabinets (ADCs) in healthcare facilities appears to be increasing, in particular within Australian hospital emergency departments (EDs). While the investment in ADCs is on the increase, no studies have specifically investigated the impacts of ADCs on medication selection and preparation error rates in EDs. Our aim was to assess the impact of ADCs on medication selection and preparation error rates in an ED of a tertiary teaching hospital. Pre intervention and post intervention study involving direct observations of nurses completing medication selection and preparation activities before and after the implementation of ADCs in the original and new emergency departments within a 377-bed tertiary teaching hospital in Australia. Medication selection and preparation error rates were calculated and compared between these two periods. Secondary end points included the impact on medication error type and severity. A total of 2087 medication selection and preparations were observed among 808 patients pre and post intervention. Implementation of ADCs in the new ED resulted in a 64.7% (1.96% versus 0.69%, respectively, P = 0.017) reduction in medication selection and preparation errors. All medication error types were reduced in the post intervention study period. There was an insignificant impact on medication error severity as all errors detected were categorised as minor. The implementation of ADCs could reduce medication selection and preparation errors and improve medication safety in an ED setting. © 2015 John Wiley & Sons, Ltd.

  12. An Analysis of Errors Committed by Saudi Non-English Major Students in the English Paragraph Writing: A Study of Comparisons

    Directory of Open Access Journals (Sweden)

    Mohammed Nuruzzaman

    2018-01-01

    Full Text Available The present study investigates the writing errors of ninety Saudi non-English major undergraduate students of different proficiency levels from three faculties, who studied English as a foundation course at the English Language Center in the College of Languages &Translation at King Khalid University, Saudi Arabia in the academic year 2016-17. The findings reveal that the common errors the Saudi EFL students make in writing English paragraphs fall under four categories namely grammar, lexis, semantics and mechanics. Then it compares the categories, types and frequency of errors committed by these three groups of students. Among these categories, grammar has been observed as the most error-prone area where students commit errors the most. The study also posits that among the three groups, the students of the College of Medicine make the minimum errors in all the types and the highest number of errors is committed by the students of Engineering College. The College of Computer Science is in the second position in making errors. The frequency of error types is also found different among these three groups.

  13. Study protocol: the empirical investigation of methods to correct for measurement error in biobanks with dietary assessment

    Directory of Open Access Journals (Sweden)

    Masson Lindsey F

    2011-10-01

    Full Text Available Abstract Background The Public Population Project in Genomics (P3G is an organisation that aims to promote collaboration between researchers in the field of population-based genomics. The main objectives of P3G are to encourage collaboration between researchers and biobankers, optimize study design, promote the harmonization of information use in biobanks, and facilitate transfer of knowledge between interested parties. The importance of calibration and harmonisation of methods for environmental exposure assessment to allow pooling of data across studies in the evaluation of gene-environment interactions has been recognised by P3G, which has set up a methodological group on calibration with the aim of; 1 reviewing the published methodological literature on measurement error correction methods with assumptions and methods of implementation; 2 reviewing the evidence available from published nutritional epidemiological studies that have used a calibration approach; 3 disseminating information in the form of a comparison chart on approaches to perform calibration studies and how to obtain correction factors in order to support research groups collaborating within the P3G network that are unfamiliar with the methods employed; 4 with application to the field of nutritional epidemiology, including gene-diet interactions, ultimately developing a inventory of the typical correction factors for various nutrients. Methods/Design Systematic review of (a the methodological literature on methods to correct for measurement error in epidemiological studies; and (b studies that have been designed primarily to investigate the association between diet and disease and have also corrected for measurement error in dietary intake. Discussion The conduct of a systematic review of the methodological literature on calibration will facilitate the evaluation of methods to correct for measurement error and the design of calibration studies for the prospective pooling of

  14. Preventing Errors in Laterality

    OpenAIRE

    Landau, Elliot; Hirschorn, David; Koutras, Iakovos; Malek, Alexander; Demissie, Seleshie

    2014-01-01

    An error in laterality is the reporting of a finding that is present on the right side as on the left or vice versa. While different medical and surgical specialties have implemented protocols to help prevent such errors, very few studies have been published that describe these errors in radiology reports and ways to prevent them. We devised a system that allows the radiologist to view reports in a separate window, displayed in a simple font and with all terms of laterality highlighted in sep...

  15. Medication Errors - A Review

    OpenAIRE

    Vinay BC; Nikhitha MK; Patel Sunil B

    2015-01-01

    In this present review article, regarding medication errors its definition, medication error problem, types of medication errors, common causes of medication errors, monitoring medication errors, consequences of medication errors, prevention of medication error and managing medication errors have been explained neatly and legibly with proper tables which is easy to understand.

  16. Al Hirschfeld's NINA as a prototype search task for studying perceptual error in radiology

    Science.gov (United States)

    Nodine, Calvin F.; Kundel, Harold L.

    1997-04-01

    Artist Al Hirschfeld has been hiding the word NINA (his daughter's name) in line drawings of theatrical scenes that have appeared in the New York Times for over 50 years. This paper shows how Hirschfeld's search task of finding the name NINA in his drawings illustrates basic perceptual principles of detection, discrimination and decision-making commonly encountered in radiology search tasks. Hirschfeld's hiding of NINA is typically accomplished by camouflaging the letters of the name and blending them into scenic background details such as wisps of hair and folds of clothing. In a similar way, pulmonary nodules and breast lesions are camouflaged by anatomic features of the chest or breast image. Hirschfeld's hidden NINAs are sometimes missed because they are integrated into a Gestalt overview rather than differentiated from background features during focal scanning. This may be similar to overlooking an obvious nodule behind the heart in a chest x-ray image. Because it is a search game, Hirschfeld assigns a number to each drawing to indicate how many NINAs he has hidden so as not to frustrate his viewers. In the radiologists' task, the number of targets detected in a medical image is determined by combining perceptual input with probabilities generated from clinical history and viewing experience. Thus, in the absence of truth, searching for abnormalities in x-ray images creates opportunities for recognition and decision errors (e.g. false positives and false negatives). We illustrate how camouflage decreases the conspicuity of both artistic and radiographic targets, compare detection performance of radiologists with lay persons searching for NINAs, and, show similarities and differences between scanning strategies of the two groups based on eye-position data.

  17. EEG Theta Dynamics within Frontal and Parietal Cortices for Error Processing during Reaching Movements in a Prism Adaptation Study Altering Visuo-Motor Predictive Planning.

    Science.gov (United States)

    Arrighi, Pieranna; Bonfiglio, Luca; Minichilli, Fabrizio; Cantore, Nicoletta; Carboncini, Maria Chiara; Piccotti, Emily; Rossi, Bruno; Andre, Paolo

    2016-01-01

    Modulation of frontal midline theta (fmθ) is observed during error commission, but little is known about the role of theta oscillations in correcting motor behaviours. We investigate EEG activity of healthy partipants executing a reaching task under variable degrees of prism-induced visuo-motor distortion and visual occlusion of the initial arm trajectory. This task introduces directional errors of different magnitudes. The discrepancy between predicted and actual movement directions (i.e. the error), at the time when visual feedback (hand appearance) became available, elicits a signal that triggers on-line movement correction. Analysis were performed on 25 EEG channels. For each participant, the median value of the angular error of all reaching trials was used to partition the EEG epochs into high- and low-error conditions. We computed event-related spectral perturbations (ERSP) time-locked either to visual feedback or to the onset of movement correction. ERSP time-locked to the onset of visual feedback showed that fmθ increased in the high- but not in the low-error condition with an approximate time lag of 200 ms. Moreover, when single epochs were sorted by the degree of motor error, fmθ started to increase when a certain level of error was exceeded and, then, scaled with error magnitude. When ERSP were time-locked to the onset of movement correction, the fmθ increase anticipated this event with an approximate time lead of 50 ms. During successive trials, an error reduction was observed which was associated with indices of adaptations (i.e., aftereffects) suggesting the need to explore if theta oscillations may facilitate learning. To our knowledge this is the first study where the EEG signal recorded during reaching movements was time-locked to the onset of the error visual feedback. This allowed us to conclude that theta oscillations putatively generated by anterior cingulate cortex activation are implicated in error processing in semi-naturalistic motor

  18. A simulation study to quantify the impacts of exposure measurement error on air pollution health risk estimates in copollutant time-series models.

    Science.gov (United States)

    BackgroundExposure measurement error in copollutant epidemiologic models has the potential to introduce bias in relative risk (RR) estimates. A simulation study was conducted using empirical data to quantify the impact of correlated measurement errors in time-series analyses of a...

  19. Computational fluid dynamics analysis and experimental study of a low measurement error temperature sensor used in climate observation.

    Science.gov (United States)

    Yang, Jie; Liu, Qingquan; Dai, Wei

    2017-02-01

    To improve the air temperature observation accuracy, a low measurement error temperature sensor is proposed. A computational fluid dynamics (CFD) method is implemented to obtain temperature errors under various environmental conditions. Then, a temperature error correction equation is obtained by fitting the CFD results using a genetic algorithm method. The low measurement error temperature sensor, a naturally ventilated radiation shield, a thermometer screen, and an aspirated temperature measurement platform are characterized in the same environment to conduct the intercomparison. The aspirated platform served as an air temperature reference. The mean temperature errors of the naturally ventilated radiation shield and the thermometer screen are 0.74 °C and 0.37 °C, respectively. In contrast, the mean temperature error of the low measurement error temperature sensor is 0.11 °C. The mean absolute error and the root mean square error between the corrected results and the measured results are 0.008 °C and 0.01 °C, respectively. The correction equation allows the temperature error of the low measurement error temperature sensor to be reduced by approximately 93.8%. The low measurement error temperature sensor proposed in this research may be helpful to provide a relatively accurate air temperature result.

  20. Error Budgeting

    Energy Technology Data Exchange (ETDEWEB)

    Vinyard, Natalia Sergeevna [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Perry, Theodore Sonne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Usov, Igor Olegovich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-04

    We calculate opacity from k (hn)=-ln[T(hv)]/pL, where T(hv) is the transmission for photon energy hv, p is sample density, and L is path length through the sample. The density and path length are measured together by Rutherford backscatter. Δk = $\\partial k$\\ $\\partial T$ ΔT + $\\partial k$\\ $\\partial (pL)$. We can re-write this in terms of fractional error as Δk/k = Δ1n(T)/T + Δ(pL)/(pL). Transmission itself is calculated from T=(U-E)/(V-E)=B/B0, where B is transmitted backlighter (BL) signal and B0 is unattenuated backlighter signal. Then ΔT/T=Δln(T)=ΔB/B+ΔB0/B0, and consequently Δk/k = 1/T (ΔB/B + ΔB$_0$/B$_0$ + Δ(pL)/(pL). Transmission is measured in the range of 0.2

  1. Uncertainty quantification and error analysis

    Energy Technology Data Exchange (ETDEWEB)

    Higdon, Dave M [Los Alamos National Laboratory; Anderson, Mark C [Los Alamos National Laboratory; Habib, Salman [Los Alamos National Laboratory; Klein, Richard [Los Alamos National Laboratory; Berliner, Mark [OHIO STATE UNIV.; Covey, Curt [LLNL; Ghattas, Omar [UNIV OF TEXAS; Graziani, Carlo [UNIV OF CHICAGO; Seager, Mark [LLNL; Sefcik, Joseph [LLNL; Stark, Philip [UC/BERKELEY; Stewart, James [SNL

    2010-01-01

    UQ studies all sources of error and uncertainty, including: systematic and stochastic measurement error; ignorance; limitations of theoretical models; limitations of numerical representations of those models; limitations on the accuracy and reliability of computations, approximations, and algorithms; and human error. A more precise definition for UQ is suggested below.

  2. Thermodynamics of Error Correction

    Directory of Open Access Journals (Sweden)

    Pablo Sartori

    2015-12-01

    Full Text Available Information processing at the molecular scale is limited by thermal fluctuations. This can cause undesired consequences in copying information since thermal noise can lead to errors that can compromise the functionality of the copy. For example, a high error rate during DNA duplication can lead to cell death. Given the importance of accurate copying at the molecular scale, it is fundamental to understand its thermodynamic features. In this paper, we derive a universal expression for the copy error as a function of entropy production and work dissipated by the system during wrong incorporations. Its derivation is based on the second law of thermodynamics; hence, its validity is independent of the details of the molecular machinery, be it any polymerase or artificial copying device. Using this expression, we find that information can be copied in three different regimes. In two of them, work is dissipated to either increase or decrease the error. In the third regime, the protocol extracts work while correcting errors, reminiscent of a Maxwell demon. As a case study, we apply our framework to study a copy protocol assisted by kinetic proofreading, and show that it can operate in any of these three regimes. We finally show that, for any effective proofreading scheme, error reduction is limited by the chemical driving of the proofreading reaction.

  3. Assessment of errors associated with plot size and lateral movement of nitrogen-15 when studying fertilizer recovery under field conditions

    International Nuclear Information System (INIS)

    Sanchez, C.A.; Blackmer, A.M.; Horton, R.; Timmons, D.R.

    1987-01-01

    The high cost of 15 N-labeled fertilizers encourages the use of field plots having minimum size. If plot size is reduced too much, however, lateral movement of N near the plots by mass flow or diffusion within the soil or by translocation through plant roots can become a significant source of error in determinations of fertilizer N recovery. This study was initiated to assess the importance of lateral movement of labeled fertilizer when unconfined plots are used to determine recovery of fertilizer. Corn grain samples were collected at various positions inside and outside 15 N plots, and the 15 N contents of these samples were determined. The data were fit to mathematical models to estimate the extent to which lateral movement of fertilizer N caused errors in determined values of fertilizer recovery for the first, second, and third crops following fertilization. These models also were used to predict the plot size needed for similar 15 N-tracer studies in the future. The results of these studies indicate that 15 N plots having a size of 2 by 2 m are sufficiently large for determining recovery of fertilizer N for corn crops under most conditions. Where lateral movement of fertilizer N in soils is suspected to be a problem, we recommend collection of a few plant samples outside the 15 N plots as insurance against misleading conclusions concerning fertilizer N recovery

  4. APPLICATION OF SIX SIGMA METHODOLOGY TO REDUCE MEDICATION ERRORS IN THE OUTPATIENT PHARMACY UNIT: A CASE STUDY FROM THE KING FAHD UNIVERSITY HOSPITAL, SAUDI ARABIA

    Directory of Open Access Journals (Sweden)

    Ahmed Al Kuwaiti

    2016-06-01

    Full Text Available Medication errors will affect the patient safety and quality of healthcare. The aim of this study is to analyze the effect of Six Sigma (DMAIC methodology in reducing medication errors in the outpatient pharmacy of King Fahd Hospital of the University, Saudi Arabia. It was conducted through the five phases of Define, Measure, Analyze, Improve, Control (DMAIC model using various quality tools. The goal was fixed as to reduce medication errors in an outpatient pharmacy by 20%. After implementation of improvement strategies, there was a marked reduction of defects and also improvement of their sigma rating. Especially, Parts per million (PPM of prescription/data entry errors reduced from 56,000 to 5,000 and its sigma rating improved from 3.09 to 4.08. This study concluded that the Six Sigma (DMAIC methodology is found to be more significant in reducing medication errors and ensuring patient safety.

  5. A STUDY OF ERRORS IN THE THIRD SINGULAR PRONOUNS OF SIMPLE PRESENT TENSE BY USING INTERLANGUAGE ANALYSIS AS AN APPROACH. A CASE STUDY

    Directory of Open Access Journals (Sweden)

    Salmon Pandarangga

    2015-03-01

    Full Text Available The purpose of this study is to analyze factors contributing to errors made in learning English as a target language (TL. Employing a case study research, the participant was interviewed for approximately 30 minutes about daily activities and experiences in learning English. This research focuses in analysing the participant‟s use of third singular pronoun in simple present tense. The findings revealed that errors made by TL learners are mainly influenced by some factorsrelated to their TL‟s and native language‟s (NL knowledge, systems and rules. These factors are coexisted and interconnected in TL learners‟ minds. This is against Robert Lado‟s argument which mentioned that learner made errors in TL learning because of the interference from NL. The study provides pedagogical implications that TL teachers should perceive errors made by the learners as a sign of language learning and development; therefore they should not be discouraged to learn. Also, TL teachers should be aware of their very important roles to help, to guide and to lead the learners‟ progress in learning the TL. The future subsequent studies should consider of involving more sample size over a longer period of time as to obtain to a more generalized finding.

  6. Dosimetric impact of systematic MLC positional errors on step and shoot IMRT for prostate cancer: a planning study

    International Nuclear Information System (INIS)

    Ung, N.M.; Harper, C.S.; Wee, L.

    2011-01-01

    Full text: The positional accuracy of multileaf collimators (MLC) is crucial in ensuring precise delivery of intensity-modulated radiotherapy (IMRT). The aim of this planning study was to investigate the dosimetric impact of systematic MLC positional errors on step and shoot IMRT of prostate cancer. A total of 12 perturbations of MLC leaf banks were introduced to six prostate IMRT treatment plans to simulate MLC systematic positional errors. Dose volume histograms (DVHs) were generated for the extraction of dose endpoint parameters. Plans were evaluated in terms of changes to the defined endpoint dose parameters, conformity index (CI) and healthy tissue avoidance (HTA) to planning target volume (PTV), rectum and bladder. Negative perturbations of MLC had been found to produce greater changes to endpoint dose parameters than positive perturbations of MLC (p 9 5 of -1.2 and 0.9% respectively. Negative and positive synchronised MLC perturbations of I mm in one direction resulted in median changes in D 9 5 of -2.3 and 1.8% respectively. Doses to rectum were generally more sensitive to systematic MLC en-ors compared to bladder (p < 0.01). Negative and positive synchronised MLC perturbations of I mm in one direction resulted in median changes in endpoint dose parameters of rectum and bladder from 1.0 to 2.5%. Maximum reduction of -4.4 and -7.3% were recorded for conformity index (CI) and healthy tissue avoidance (HT A) respectively due to synchronised MLC perturbation of 1 mm. MLC errors resulted in dosimetric changes in IMRT plans for prostate. (author)

  7. Evaluation and Comparison of the Processing Methods of Airborne Gravimetry Concerning the Errors Effects on Downward Continuation Results: Case Studies in Louisiana (USA) and the Tibetan Plateau (China).

    Science.gov (United States)

    Zhao, Qilong; Strykowski, Gabriel; Li, Jiancheng; Pan, Xiong; Xu, Xinyu

    2017-05-25

    Gravity data gaps in mountainous areas are nowadays often filled in with the data from airborne gravity surveys. Because of the errors caused by the airborne gravimeter sensors, and because of rough flight conditions, such errors cannot be completely eliminated. The precision of the gravity disturbances generated by the airborne gravimetry is around 3-5 mgal. A major obstacle in using airborne gravimetry are the errors caused by the downward continuation. In order to improve the results the external high-accuracy gravity information e.g., from the surface data can be used for high frequency correction, while satellite information can be applying for low frequency correction. Surface data may be used to reduce the systematic errors, while regularization methods can reduce the random errors in downward continuation. Airborne gravity surveys are sometimes conducted in mountainous areas and the most extreme area of the world for this type of survey is the Tibetan Plateau. Since there are no high-accuracy surface gravity data available for this area, the above error minimization method involving the external gravity data cannot be used. We propose a semi-parametric downward continuation method in combination with regularization to suppress the systematic error effect and the random error effect in the Tibetan Plateau; i.e., without the use of the external high-accuracy gravity data. We use a Louisiana airborne gravity dataset from the USA National Oceanic and Atmospheric Administration (NOAA) to demonstrate that the new method works effectively. Furthermore, and for the Tibetan Plateau we show that the numerical experiment is also successfully conducted using the synthetic Earth Gravitational Model 2008 (EGM08)-derived gravity data contaminated with the synthetic errors. The estimated systematic errors generated by the method are close to the simulated values. In addition, we study the relationship between the downward continuation altitudes and the error effect. The

  8. Evaluation and Comparison of the Processing Methods of Airborne Gravimetry Concerning the Errors Effects on Downward Continuation Results: Case Studies in Louisiana (USA) and the Tibetan Plateau (China)

    Science.gov (United States)

    Zhao, Q.

    2017-12-01

    Gravity data gaps in mountainous areas are nowadays often filled in with the data from airborne gravity surveys. Because of the errors caused by the airborne gravimeter sensors, and because of rough flight conditions, such errors cannot be completely eliminated. The precision of the gravity disturbances generated by the airborne gravimetry is around 3-5 mgal. A major obstacle in using airborne gravimetry are the errors caused by the downward continuation. In order to improve the results the external high-accuracy gravity information e.g., from the surface data can be used for high frequency correction, while satellite information can be applying for low frequency correction. Surface data may be used to reduce the systematic errors, while regularization methods can reduce the random errors in downward continuation. Airborne gravity surveys are sometimes conducted in mountainous areas and the most extreme area of the world for this type of survey is the Tibetan Plateau. Since there are no high-accuracy surface gravity data available for this area, the above error minimization method involving the external gravity data cannot be used. We propose a semi-parametric downward continuation method in combination with regularization to suppress the systematic error effect and the random error effect in the Tibetan Plateau; i.e., without the use of the external high-accuracy gravity data. We use a Louisiana airborne gravity dataset from the USA National Oceanic and Atmospheric Administration (NOAA) to demonstrate that the new method works effectively. Furthermore, and for the Tibetan Plateau we show that the numerical experiment is also successfully conducted using the synthetic Earth Gravitational Model 2008 (EGM08)-derived gravity data contaminated with the synthetic errors. The estimated systematic errors generated by the method are close to the simulated values. In addition, we study the relationship between the downward continuation altitudes and the error effect. The

  9. Linking Errors between Two Populations and Tests: A Case Study in International Surveys in Education

    Science.gov (United States)

    Hastedt, Dirk; Desa, Deana

    2015-01-01

    This simulation study was prompted by the current increased interest in linking national studies to international large-scale assessments (ILSAs) such as IEA's TIMSS, IEA's PIRLS, and OECD's PISA. Linkage in this scenario is achieved by including items from the international assessments in the national assessments on the premise that the average…

  10. Predictors of Errors of Novice Java Programmers

    Science.gov (United States)

    Bringula, Rex P.; Manabat, Geecee Maybelline A.; Tolentino, Miguel Angelo A.; Torres, Edmon L.

    2012-01-01

    This descriptive study determined which of the sources of errors would predict the errors committed by novice Java programmers. Descriptive statistics revealed that the respondents perceived that they committed the identified eighteen errors infrequently. Thought error was perceived to be the main source of error during the laboratory programming…

  11. Potential errors and misuse of statistics in studies on leakage in endodontics.

    Science.gov (United States)

    Lucena, C; Lopez, J M; Pulgar, R; Abalos, C; Valderrama, M J

    2013-04-01

    To assess the quality of the statistical methodology used in studies of leakage in Endodontics, and to compare the results found using appropriate versus inappropriate inferential statistical methods. The search strategy used the descriptors 'root filling' 'microleakage', 'dye penetration', 'dye leakage', 'polymicrobial leakage' and 'fluid filtration' for the time interval 2001-2010 in journals within the categories 'Dentistry, Oral Surgery and Medicine' and 'Materials Science, Biomaterials' of the Journal Citation Report. All retrieved articles were reviewed to find potential pitfalls in statistical methodology that may be encountered during study design, data management or data analysis. The database included 209 papers. In all the studies reviewed, the statistical methods used were appropriate for the category attributed to the outcome variable, but in 41% of the cases, the chi-square test or parametric methods were inappropriately selected subsequently. In 2% of the papers, no statistical test was used. In 99% of cases, a statistically 'significant' or 'not significant' effect was reported as a main finding, whilst only 1% also presented an estimation of the magnitude of the effect. When the appropriate statistical methods were applied in the studies with originally inappropriate data analysis, the conclusions changed in 19% of the cases. Statistical deficiencies in leakage studies may affect their results and interpretation and might be one of the reasons for the poor agreement amongst the reported findings. Therefore, more effort should be made to standardize statistical methodology. © 2012 International Endodontic Journal.

  12. Learning from Errors

    Directory of Open Access Journals (Sweden)

    MA. Lendita Kryeziu

    2015-06-01

    Full Text Available “Errare humanum est”, a well known and widespread Latin proverb which states that: to err is human, and that people make mistakes all the time. However, what counts is that people must learn from mistakes. On these grounds Steve Jobs stated: “Sometimes when you innovate, you make mistakes. It is best to admit them quickly, and get on with improving your other innovations.” Similarly, in learning new language, learners make mistakes, thus it is important to accept them, learn from them, discover the reason why they make them, improve and move on. The significance of studying errors is described by Corder as: “There have always been two justifications proposed for the study of learners' errors: the pedagogical justification, namely that a good understanding of the nature of error is necessary before a systematic means of eradicating them could be found, and the theoretical justification, which claims that a study of learners' errors is part of the systematic study of the learners' language which is itself necessary to an understanding of the process of second language acquisition” (Corder, 1982; 1. Thus the importance and the aim of this paper is analyzing errors in the process of second language acquisition and the way we teachers can benefit from mistakes to help students improve themselves while giving the proper feedback.

  13. A Study of the Spelling Errors committed by Students of English in Saudi Arabia: Exploration and Remedial Measures

    Directory of Open Access Journals (Sweden)

    Paikar Fatima Mazhar Hameed

    2016-02-01

    Full Text Available The craziness of English spelling has undeniably perplexed learners, especially in an EFL context as in the Kingdom of Saudi Arabia. In these situations, among other obstacles, learners also have to tackle the perpetual and unavoidable problem of MT interference. Sadly, this perplexity takes the shape of a real problem in the language classroom where the English teacher has a tough time rationalizing with the learners why ‘cough’ is not spelt as /kuf/ or ‘knee’ has to do with a silent /k/. It is observed that students of English as second/foreign language in Saudi Arabia commit spelling errors that cause not only a lot of confusion to the teachers but also lower the self-esteem of the students concerned. The current study aims to identify the key problem areas as far as English spelling ability of Saudi EFL learners is concerned. It aims to also suggest remedial and pedagogical measures to improve the learners’ competence in this crucial, though hitherto, nascent skill area in the Saudi education system. Keywords: EFL; error-pattern, spelling instructions, orthography, phonology, vocabulary, language skills, language users

  14. Nurses' systems thinking competency, medical error reporting, and the occurrence of adverse events: a cross-sectional study.

    Science.gov (United States)

    Hwang, Jee-In; Park, Hyeoun-Ae

    2017-12-01

    Healthcare professionals' systems thinking is emphasized for patient safety. To report nurses' systems thinking competency, and its relationship with medical error reporting and the occurrence of adverse events. A cross-sectional survey using a previously validated Systems Thinking Scale (STS), was conducted. Nurses from two teaching hospitals were invited to participate in the survey. There were 407 (60.3%) completed surveys. The mean STS score was 54.5 (SD 7.3) out of 80. Nurses with higher STS scores were more likely to report medical errors (odds ratio (OR) = 1.05; 95% confidence interval (CI) = 1.02-1.08) and were less likely to be involved in the occurrence of adverse events (OR = 0.96; 95% CI = 0.93-0.98). Nurses showed moderate systems thinking competency. Systems thinking was a significant factor associated with patient safety. Impact Statement: The findings of this study highlight the importance of enhancing nurses' systems thinking capacity to promote patient safety.

  15. Preanalytical errors in primary healthcare: a questionnaire study of information search procedures, test request management and test tube labelling.

    Science.gov (United States)

    Söderberg, Johan; Brulin, Christine; Grankvist, Kjell; Wallin, Olof

    2009-01-01

    Most errors in laboratory medicine occur in the preanalytical phase and are the result of human mistakes. This study investigated information search procedures, test request management and test tube labelling in primary healthcare compared to the same procedures amongst clinical laboratory staff. A questionnaire was completed by 317 venous blood sampling staff in 70 primary healthcare centres and in two clinical laboratories (response rate = 94%). Correct procedures were not always followed. Only 60% of the primary healthcare staff reported that they always sought information in the updated, online laboratory manual. Only 12% reported that they always labelled the test tubes prior to drawing blood samples. No major differences between primary healthcare centres and clinical laboratories were found, except for test tube labelling, whereby the laboratory staff reported better practices. Re-education and access to documented routines were not clearly associated with better practices. The preanalytical procedure in the surveyed primary healthcare centres was associated with a risk of errors which could affect patient safety. To improve patient safety in laboratory testing, all healthcare providers should survey their preanalytical procedures and improve the total testing process with a systems perspective.

  16. Studying the effect of perceptual errors on the decisions made by the ...

    African Journals Online (AJOL)

    The factors that the investors are not aware of their effectiveness and make investment decisions. The main purpose of the present research is to study the perceptual factors affecting on the decision making process of the investors and the effect of information on these factors. For this aim, 385 investors of Tehran Stock ...

  17. Measurement Error Correction Formula for Cluster-Level Group Differences in Cluster Randomized and Observational Studies

    Science.gov (United States)

    Cho, Sun-Joo; Preacher, Kristopher J.

    2016-01-01

    Multilevel modeling (MLM) is frequently used to detect cluster-level group differences in cluster randomized trial and observational studies. Group differences on the outcomes (posttest scores) are detected by controlling for the covariate (pretest scores) as a proxy variable for unobserved factors that predict future attributes. The pretest and…

  18. Error Patterns in Word Reading among Primary School Children: A Cross-Orthographic Study

    Science.gov (United States)

    Guron, Louise Miller; Lundberg, Ingvar

    2004-01-01

    A comparative investigation of word reading efficiency indicates that different strategies may be used by English and Swedish early readers. In a first study, 328 native English speakers from UK Years 3 and 6 completed a pen-and-paper word recognition task (the "Wordchains" test). Results were analysed for frequency and type of errors…

  19. A Study on Large Display Panel Design for the Countermeasures against Team Errors within the Main Control Room of APR-1400

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sa Kil; Lee, Yong Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The personal aspect of human errors has been mainly overcome by virtue of the education and training. However, in the system aspect, the education and training system needs to be reconsidered for more effective reduction of human errors affected from various systems hazards. Traditionally the education and training systems are mainly not focused on team skills such as communication, situational awareness, and coordination, etc. but individual knowledge, skill, and attitude. However, the team factor is one of the crucial issues to reduce the human errors in most industries. In this study, we identify the emerging types of team errors, especially, in digitalized control room of nuclear power plants such as the APR-1400 main control room. Most works in nuclear industry are to be performed by a team of more than two persons. Even though the individual errors can be detected and recovered by the qualified others and/or the well trained team, it is rather seldom that the errors by team could be easily detected and properly recovered by the team itself. Note that the team is defined as two or more people who are appropriately interacting with each other, and the team is a dependent aggregate, which accomplishes a valuable goal. Team error is one of the typical organizational errors that may occur during performing operations in nuclear power plants. The large display panel is a representative feature of digitalized control room. As a group-view display, the large display panel provides plant overview to the operators. However, in terms of team performance and team errors, the large display panel is on a discussion board still because the large display panel was designed just a concept of passive display. In this study, we will propose revised large display panel which is integrated with several alternative interfaces against feasible team errors.

  20. A Study on Large Display Panel Design for the Countermeasures against Team Errors within the Main Control Room of APR-1400

    International Nuclear Information System (INIS)

    Kim, Sa Kil; Lee, Yong Hee

    2015-01-01

    The personal aspect of human errors has been mainly overcome by virtue of the education and training. However, in the system aspect, the education and training system needs to be reconsidered for more effective reduction of human errors affected from various systems hazards. Traditionally the education and training systems are mainly not focused on team skills such as communication, situational awareness, and coordination, etc. but individual knowledge, skill, and attitude. However, the team factor is one of the crucial issues to reduce the human errors in most industries. In this study, we identify the emerging types of team errors, especially, in digitalized control room of nuclear power plants such as the APR-1400 main control room. Most works in nuclear industry are to be performed by a team of more than two persons. Even though the individual errors can be detected and recovered by the qualified others and/or the well trained team, it is rather seldom that the errors by team could be easily detected and properly recovered by the team itself. Note that the team is defined as two or more people who are appropriately interacting with each other, and the team is a dependent aggregate, which accomplishes a valuable goal. Team error is one of the typical organizational errors that may occur during performing operations in nuclear power plants. The large display panel is a representative feature of digitalized control room. As a group-view display, the large display panel provides plant overview to the operators. However, in terms of team performance and team errors, the large display panel is on a discussion board still because the large display panel was designed just a concept of passive display. In this study, we will propose revised large display panel which is integrated with several alternative interfaces against feasible team errors

  1. Human Error Analysis Project (HEAP) - The Fourth Pilot Study: Scoring and Analysis of Raw Data Types

    International Nuclear Information System (INIS)

    Hollnagel, Erik; Braarud; Per Oeyvind; Droeivoldsmo, Asgeir; Follesoe; Knut; Helgar, Stein; Kaarstad, Magnhild

    1996-01-01

    Pilot study No. 4 rounded off the series of pilot studies by looking at the important issue of the quality of the various data sources. The preceding experiments had clearly shown that that it was necessary to use both concurrent and interrupted verbal protocols, and also that information about eye movements was very valuable. The effort and resources needed to analyse a combination of the different data sources is, however, significant, and it was therefore important to find out whether one or more of the data sources could replace another. In order to determine this issue, pilot study No. 4 looked specifically at the quality of information provided by different data sources. The main hypotheses were that information about operators' diagnosis and decision making would be provided by verbal protocols, expert commentators, and auto-confrontation protocols, that the data sources would be valid, and that they would complement each other. The study used three main data sources: (1) concurrent verbal protocols, which were the operators' verbalisations during the experiment; (2) expert commentator reports, which were descriptions by process experts of the operators' performance; and (3) auto-confrontation, which were the operators' comments on their performance based on a replay of the performance recording minus the concurrent verbal protocol. Additional data sources were eye movement recordings, process data, alarms, etc. The three main data sources were treated as independent variables and applied according to an experimental design that facilitated the test of the main hypotheses. The pilot study produced altogether 59 verbal protocols, some of which were in Finnish. After a translation into English, each protocol was analysed and scored according to a specific scheme. The scoring was designed to facilitate the evaluation of the experimental hypotheses. Due to the considerable work involved, the analysis process has only been partly completed, and no firm results

  2. Sensitivity to Measurement Errors in Studies on Prosocial Choice using a Two-Choice Paradigm

    Directory of Open Access Journals (Sweden)

    Sikorska Julia

    2016-12-01

    Full Text Available Research on prosocial behaviors in primates often relies on the two-choice paradigm. Motoric lateralization is a surprisingly big problem in this field of research research, as it may influence which lever will ultimately be chosen by the actor. The results of lateralization studies on primates do not form a clear picture of that phenomenon, which makes it difficult to address the problem during research. The authors discuss possible ways of managing this confounding variable.

  3. Extent and Determinants of Error in Doctors' Prognoses in Terminally Ill Patients: Prospective Cohort Study

    OpenAIRE

    Lamont, Elizabeth; Christakis, Nicholas

    2000-01-01

    Objective: To describe doctors' prognostic accuracy in terminally ill patients and to evaluate the determinants of that accuracy. Design: Prospective cohort study. Setting: Five outpatient hospice programmes in Chicago. Participants: 343 doctors provided survival estimates for 468 terminally ill patients at the time of hospice referral. Main outcome measures: Patients' estimated and actual survival. Results: Median survival was 24 days. Only 20% (92/468) of predictions were acc...

  4. Prevalence and risk factors for refractive errors in the South Indian adult population: The Andhra Pradesh Eye disease study

    Directory of Open Access Journals (Sweden)

    Sannapaneni Krishnaiah

    2008-12-01

    Full Text Available Sannapaneni Krishnaiah1,2,3, Marmamula Srinivas1,2,3, Rohit C Khanna1,2, Gullapalli N Rao1,2,31L V Prasad Eye Institute, Banjara Hills, Hyderabad, India; 2International Center for Advancement of Rural Eye Care, L V Prasad Eye Institute, Banjara Hills, Hyderabad, India; 3Vision CRC, University of New South Wales, Sydney, NSW, AustraliaAim: To report the prevalence, risk factors and associated population attributable risk percentage (PAR for refractive errors in the South Indian adult population.Methods: A population-based cross-sectional epidemiologic study was conducted in the Indian state of Andhra Pradesh. A multistage cluster, systematic, stratified random sampling method was used to obtain participants (n = 10293 for this study.Results: The age-gender-area-adjusted prevalence rates in those ≥40 years of age were determined for myopia (spherical equivalent [SE] < −0.5 D 34.6% (95% confidence interval [CI]: 33.1–36.1, high-myopia (SE < −5.0 D 4.5% (95% CI: 3.8–5.2, hyperopia (SE > +0.5 D 18.4% (95% CI: 17.1–19.7, astigmatism (cylinder < −0.5 D 37.6% (95% CI: 36–39.2, and anisometropia (SE difference between right and left eyes >0.5 D 13.0% (95% CI: 11.9–14.1. The prevalence of myopia, astigmatism, high-myopia, and anisometropia significantly increased with increasing age (all p < 0.0001. There was no gender difference in prevalence rates in any type of refractive error, though women had a significantly higher rate of hyperopia than men (p < 0.0001. Hyperopia was significantly higher among those with a higher educational level (odds ratio [OR] 2.49; 95% CI: 1.51–3.95 and significantly higher among the hypertensive group (OR 1.24; 95% CI: 1.03–1.49. The severity of lens nuclear opacity was positively associated with myopia and negatively associated with hyperopia.Conclusions: The prevalence of myopia in this adult Indian population is much higher than in similarly aged white populations. These results confirm the previously

  5. Refractive error, visual acuity and causes of vision loss in children in Shandong, China. The Shandong Children Eye Study.

    Directory of Open Access Journals (Sweden)

    Jian Feng Wu

    Full Text Available PURPOSE: To examine the prevalence of refractive errors and prevalence and causes of vision loss among preschool and school children in East China. METHODS: Using a random cluster sampling in a cross-sectional school-based study design, children with an age of 4-18 years were selected from kindergartens, primary schools, and junior and senior high schools in the rural Guanxian County and the city of Weihai. All children underwent a complete ocular examination including measurement of uncorrected (UCVA and best corrected visual acuity (BCVA and auto-refractometry under cycloplegia. Myopia was defined as refractive error of ≤-0.5 diopters (D, high myopia as ≤ -6.0D, and amblyopia as BCVA ≤ 20/32 without any obvious reason for vision reduction and with strabismus or refractive errors as potential reasons. RESULTS: Out of 6364 eligible children, 6026 (94.7% children participated. Prevalence of myopia (overall: 36.9 ± 0.6%;95% confidence interval (CI:36.0,38.0 increased (P<0.001 from 1.7 ± 1.2% (95%CI:0.0,4.0 in the 4-years olds to 84.6 ± 3.2% (95%CI:78.0,91.0 in 17-years olds. Myopia was associated with older age (OR:1.56;95%CI:1.52,1.60;P<0.001, female gender (OR:1.22;95%CI:1.08,1.39;P = 0.002 and urban region (OR:2.88;95%CI:2.53,3.29;P<0.001. Prevalence of high myopia (2.0 ± 0.2% increased from 0.7 ± 0.3% (95%CI:0.1,1.3 in 10-years olds to 13.9 ± 3.0 (95%CI:7.8,19.9 in 17-years olds. It was associated with older age (OR:1.50;95%CI:1.41,1.60;P<0.001 and urban region (OR:3.11;95%CI:2.08,4.66;P<0.001. Astigmatism (≥ 0.75D (36.3 ± 0.6%;95%CI:35.0,38.0 was associated with older age (P<0.001;OR:1.06;95%CI:1.04,1.09, more myopic refractive error (P<0.001;OR:0.94;95%CI:0.91,0.97 and urban region (P<0.001;OR:1.47;95%CI:1.31,1.64. BCVA was ≤ 20/40 in the better eye in 19 (0.32% children. UCVA ≤ 20/40 in at least one eye was found in 2046 (34.05% children, with undercorrected refractive error as cause in 1975 (32.9% children. Amblyopia

  6. Effects of measurement errors on psychometric measurements in ergonomics studies: Implications for correlations, ANOVA, linear regression, factor analysis, and linear discriminant analysis.

    Science.gov (United States)

    Liu, Yan; Salvendy, Gavriel

    2009-05-01

    This paper aims to demonstrate the effects of measurement errors on psychometric measurements in ergonomics studies. A variety of sources can cause random measurement errors in ergonomics studies and these errors can distort virtually every statistic computed and lead investigators to erroneous conclusions. The effects of measurement errors on five most widely used statistical analysis tools have been discussed and illustrated: correlation; ANOVA; linear regression; factor analysis; linear discriminant analysis. It has been shown that measurement errors can greatly attenuate correlations between variables, reduce statistical power of ANOVA, distort (overestimate, underestimate or even change the sign of) regression coefficients, underrate the explanation contributions of the most important factors in factor analysis and depreciate the significance of discriminant function and discrimination abilities of individual variables in discrimination analysis. The discussions will be restricted to subjective scales and survey methods and their reliability estimates. Other methods applied in ergonomics research, such as physical and electrophysiological measurements and chemical and biomedical analysis methods, also have issues of measurement errors, but they are beyond the scope of this paper. As there has been increasing interest in the development and testing of theories in ergonomics research, it has become very important for ergonomics researchers to understand the effects of measurement errors on their experiment results, which the authors believe is very critical to research progress in theory development and cumulative knowledge in the ergonomics field.

  7. Optical 'dampening' of the refractive error to axial length ratio: implications for outcome measures in myopia control studies.

    Science.gov (United States)

    Cruickshank, Fiona E; Logan, Nicola S

    2018-05-01

    To gauge the extent to which differences in the refractive error axial length relationship predicted by geometrical optics are observed in actual refractive/biometric data. This study is a retrospective analysis of existing data. Right eye refractive error [RX] and axial length [AXL] data were collected on 343 6-to-7-year-old children [mean 7.18 years (S.D. 0.35)], 294 12-to-13-year-old children [mean 13.12 years (S.D. 0.32)] and 123 young adults aged 18-to-25-years [mean 20.56 years (S.D. 1.91)]. Distance RX was measured with the Shin-Nippon NVision-K 5001 infrared open-field autorefractor. Child participants were cyclopleged prior to data collection (1% Cyclopentolate Hydrochloride). Myopia was defined as a mean spherical equivalent [MSE] ≤-0.50 D. Axial length was measured using the Zeiss IOLMaster 500. Optical modelling was based on ray tracing and manipulation of parameters of a Gullstrand reduced model eye. There was a myopic shift in mean MSE with age (6-7 years +0.87 D, 12-13 years -0.06 D and 18-25 years -1.41 D), associated with an increase in mean AXL (6-7 years 22.70 mm, 12-13 years 23.49 mm and 18-25 years 23.98 mm). There was a significant negative correlation between MSE and AXL for all age groups (all p theory predicts that there will be a reduction in the RX: AXL ratio with longer eyes. The participant data although adhering to this theory show a reduced effect, with eyes with longer axial lengths having a lower refractive error to axial length ratio than predicted by model eye calculations. We propose that in myopia control intervention studies when comparing efficacy, consideration should be given to the dampening effect seen with a longer eye. © 2018 The Authors. Ophthalmic and Physiological Optics published by John Wiley & Sons Ltd on behalf of College of Optometrists.

  8. Diffraction study of duty-cycle error in ferroelectric quasi-phase-matching gratings with Gaussian beam illumination

    Science.gov (United States)

    Dwivedi, Prashant Povel; Kumar, Challa Sesha Sai Pavan; Choi, Hee Joo; Cha, Myoungsik

    2016-02-01

    Random duty-cycle error (RDE) is inherent in the fabrication of ferroelectric quasi-phase-matching (QPM) gratings. Although a small RDE may not affect the nonlinearity of QPM devices, it enhances non-phase-matched parasitic harmonic generations, limiting the device performance in some applications. Recently, we demonstrated a simple method for measuring the RDE in QPM gratings by analyzing the far-field diffraction pattern obtained by uniform illumination (Dwivedi et al. in Opt Express 21:30221-30226, 2013). In the present study, we used a Gaussian beam illumination for the diffraction experiment to measure noise spectra that are less affected by the pedestals of the strong diffraction orders. Our results were compared with our calculations based on a random grating model, demonstrating improved resolution in the RDE estimation.

  9. Avoiding Systematic Errors in Isometric Squat-Related Studies without Pre-Familiarization by Using Sufficient Numbers of Trials

    Directory of Open Access Journals (Sweden)

    Pekünlü Ekim

    2014-10-01

    Full Text Available There is no scientific evidence in the literature indicating that maximal isometric strength measures can be assessed within 3 trials. We questioned whether the results of isometric squat-related studies in which maximal isometric squat strength (MISS testing was performed using limited numbers of trials without pre-familiarization might have included systematic errors, especially those resulting from acute learning effects. Forty resistance-trained male participants performed 8 isometric squat trials without pre-familiarization. The highest measures in the first “n” trials (3 ≤ n ≤ 8 of these 8 squats were regarded as MISS obtained using 6 different MISS test methods featuring different numbers of trials (The Best of n Trials Method [BnT]. When B3T and B8T were paired with other methods, high reliability was found between the paired methods in terms of intraclass correlation coefficients (0.93-0.98 and coefficients of variation (3.4-7.0%. The Wilcoxon’s signed rank test indicated that MISS obtained using B3T and B8T were lower (p < 0.001 and higher (p < 0.001, respectively, than those obtained using other methods. The Bland- Altman method revealed a lack of agreement between any of the paired methods. Simulation studies illustrated that increasing the number of trials to 9-10 using a relatively large sample size (i.e., ≥ 24 could be an effective means of obtaining the actual MISS values of the participants. The common use of a limited number of trials in MISS tests without pre-familiarization appears to have no solid scientific base. Our findings suggest that the number of trials should be increased in commonly used MISS tests to avoid learning effect-related systematic errors

  10. Electrochemical sensors applied to pollution monitoring: Measurement error and gas ratio bias - A volcano plume case study

    Science.gov (United States)

    Roberts, T. J.; Saffell, J. R.; Oppenheimer, C.; Lurton, T.

    2014-06-01

    There is an increasing scientific interest in the use of miniature electrochemical sensors to detect and quantify atmospheric trace gases. This has led to the development of ‘Multi-Gas' systems applied to measurements of both volcanic gas emissions, and urban air pollution. However, such measurements are subject to uncertainties introduced by sensor response time, a critical issue that has received limited attention to date. Here, a detailed analysis of output from an electrochemical SO2 sensor and two H2S sensors (contrasting in their time responses and cross-sensitivities) demonstrates how instrument errors arise under the conditions of rapidly fluctuating (by dilution) gas abundances, leading to scatter and importantly bias in the reported gas ratios. In a case study at Miyakejima volcano (Japan), electrochemical sensors were deployed at both the crater-rim and downwind locations, thereby exposed to rapidly fluctuating and smoothly varying plume gas concentrations, respectively. Discrepancies in the H2S/SO2 gas mixing ratios derived from these measurements are attributed to the sensors' differing time responses to SO2 and H2S under fluctuating plume conditions, with errors magnified by the need to correct for SO2 interference in the H2S readings. Development of a sensor response model that reproduces sensor t90 behaviour (the time required to reach 90% of the final signal following a step change in gas abundance) during calibration enabled this measurement error to be simulated numerically. The sensor response times were characterised as SO2 sensor (t90 ~ 13 s), H2S sensor without interference (t90 ~ 11 s), and H2S sensor with interference (t90 ~ 20 s to H2S and ~ 32 s to SO2). We show that a method involving data integration between periods of episodic plume exposure identifiable in the sensor output yields a less biased H2S/SO2 ratio estimate than that derived from standard analysis approaches. For the Miyakejima crater-rim dataset this method yields highly

  11. The effect of a clinical pharmacist-led training programme on intravenous medication errors : a controlled before and after study

    NARCIS (Netherlands)

    Nguyen, Huong; Pham, Hong-Tham; Vo, Dang-Khoa; Nguyen, Tuan-Dung; van den Heuvel, Edwin R.; Haaijer-Ruskamp, Flora M.; Taxis, Katja

    Background Little is known about interventions to reduce intravenous medication administration errors in hospitals, especially in low-and middle-income countries. Objective To assess the effect of a clinical pharmacist-led training programme on clinically relevant errors during intravenous

  12. The Relationships Among Perceived Patients' Safety Culture, Intention to Report Errors, and Leader Coaching Behavior of Nurses in Korea: A Pilot Study.

    Science.gov (United States)

    Ko, YuKyung; Yu, Soyoung

    2017-09-01

    This study was undertaken to explore the correlations among nurses' perceptions of patient safety culture, their intention to report errors, and leader coaching behaviors. The participants (N = 289) were nurses from 5 Korean hospitals with approximately 300 to 500 beds each. Sociodemographic variables, patient safety culture, intention to report errors, and coaching behavior were measured using self-report instruments. Data were analyzed using descriptive statistics, Pearson correlation coefficient, the t test, and the Mann-Whitney U test. Nurses' perceptions of patient safety culture and their intention to report errors showed significant differences between groups of nurses who rated their leaders as high-performing or low-performing coaches. Perceived coaching behavior showed a significant, positive correlation with patient safety culture and intention to report errors, i.e., as nurses' perceptions of coaching behaviors increased, so did their ratings of patient safety culture and error reporting. There is a need in health care settings for coaching by nurse managers to provide quality nursing care and thus improve patient safety. Programs that are systematically developed and implemented to enhance the coaching behaviors of nurse managers are crucial to the improvement of patient safety and nursing care. Moreover, a systematic analysis of the causes of malpractice, as opposed to a focus on the punitive consequences of errors, could increase error reporting and therefore promote a culture in which a higher level of patient safety can thrive.

  13. Quantifying errors and omissions in alien species lists: The introduction status of Melaleuca species in South Africa as a case study

    Directory of Open Access Journals (Sweden)

    Llewellyn Jacobs

    2017-01-01

    Full Text Available Introduced species lists provide essential background information for biological invasions research and management. The compilation of these lists is, however, prone to a variety of errors. We highlight the frequency and consequences of such errors using introduced Melaleuca (sensu lato, including Callistemon species in South Africa as a case study. We examined 111 herbarium specimens from South Africa and noted the categories and sub-categories of errors that occurred in identification. We also used information from herbarium specimens and distribution data collected in the field to determine whether a species was introduced, naturalized and invasive. We found that 72% of the specimens were not named correctly. These were due to human error (70% (misidentification, and improved identifications and species identification problems (30% (synonyms arising from inclusion of Callistemon, and unresolved taxonomy. At least 36 Melaleuca species have been introduced to South Africa, and field observations indicate that ten of these have naturalized, including five that are invasive. While most of the errors likely have negligible impact on management, we highlight one case where incorrect identification lead to an inappropriate management approach and some instances of errors in published lists. Invasive species lists need to be carefully reviewed to minimise errors, and herbarium specimens supported by DNA identification are required where identification using morphological features is particularly challenging.

  14. Interfractional and intrafractional errors assessed by daily cone-beam computed tomography in nasopharyngeal carcinoma treated with intensity-modulated radiation therapy. A prospective study

    International Nuclear Information System (INIS)

    Lu Heming; Lin Hui; Feng Guosheng

    2012-01-01

    This prospective study was to assess interfractional and intrafractional errors and to estimate appropriate margins for planning target volume (PTV) by using daily cone-beam computed tomography (CBCT) guidance in nasopharyngeal carcinoma (NPC). Daily pretreatment and post-treatment CBCT scans were acquired separately after initial patient setup and after the completion of each treatment fraction in 10 patients treated with intensity-modulated radiation therapy (IMRT). Online corrections were made before treatment if any translational setup error was found. Interfractional and intrafractional errors were recorded in the right-left (RL), superior-inferior (SI) and anterior-posterior (AP) directions. For the translational shifts, interfractional errors >2 mm occurred in 21.7% of measurements in the RL direction, 12.7% in the SI direction and 34.1% in the AP direction, respectively. Online correction resulted in 100% of residual errors ≤2 mm in the RL and SI directions, and 95.5% of residual errors ≤2 mm in the AP direction. No residual errors >3 mm occurred in the three directions. For the rotational shifts, a significant reduction was found in the magnitudes of residual errors compared with those of interfractional errors. A margin of 4.9 mm, 4.0 mm and 6.3 mm was required in the RL, SI and AP directions, respectively, when daily CBCT scans were not performed. With daily CBCT, the margins were reduced to 1.2 mm in all directions. In conclusion, daily CBCT guidance is an effective modality to improve the accuracy of IMRT for NPC. The online correction could result in a 70-81% reduction in margin size. (author)

  15. Modeling coherent errors in quantum error correction

    Science.gov (United States)

    Greenbaum, Daniel; Dutton, Zachary

    2018-01-01

    Analysis of quantum error correcting codes is typically done using a stochastic, Pauli channel error model for describing the noise on physical qubits. However, it was recently found that coherent errors (systematic rotations) on physical data qubits result in both physical and logical error rates that differ significantly from those predicted by a Pauli model. Here we examine the accuracy of the Pauli approximation for noise containing coherent errors (characterized by a rotation angle ɛ) under the repetition code. We derive an analytic expression for the logical error channel as a function of arbitrary code distance d and concatenation level n, in the small error limit. We find that coherent physical errors result in logical errors that are partially coherent and therefore non-Pauli. However, the coherent part of the logical error is negligible at fewer than {ε }-({dn-1)} error correction cycles when the decoder is optimized for independent Pauli errors, thus providing a regime of validity for the Pauli approximation. Above this number of correction cycles, the persistent coherent logical error will cause logical failure more quickly than the Pauli model would predict, and this may need to be combated with coherent suppression methods at the physical level or larger codes.

  16. Comparison of adsorption equilibrium models and error functions for the study of sulfate removal by calcium hydroxyapatite microfibrillated cellulose composite.

    Science.gov (United States)

    Hokkanen, Sanna; Bhatnagar, Amit; Koistinen, Ari; Kangas, Teija; Lassi, Ulla; Sillanpää, Mika

    2018-04-01

    In the present study, the adsorption of sulfates of sodium sulfate (Na 2 SO 4 ) and sodium lauryl sulfate (SLS) by calcium hydroxyapatite-modified microfibrillated cellulose was studied in the aqueous solution. The adsorbent was characterized using elemental analysis, Fourier transform infrared, scanning electron microscope and elemental analysis in order to gain the information on its structure and physico-chemical properties. The adsorption studies were conducted in batch mode. The effects of solution pH, contact time, the initial concentration of sulfate and the effect of competing anions were studied on the performance of synthesized adsorbent for sulfate removal. Adsorption kinetics indicated very fast adsorption rate for sulfate of both sources (Na 2 SO 4 and SLS) and the adsorption process was well described by the pseudo-second-order kinetic model. Experimental maximum adsorption capacities were found to be 34.53 mg g -1 for sulfates of SLS and 7.35 mg g -1 for sulfates of Na 2 SO 4. The equilibrium data were described by the Langmuir, Sips, Freundlich, Toth and Redlich-Peterson isotherm models using five different error functions.

  17. EEG Theta Dynamics within Frontal and Parietal Cortices for Error Processing during Reaching Movements in a Prism Adaptation Study Altering Visuo-Motor Predictive Planning.

    Directory of Open Access Journals (Sweden)

    Pieranna Arrighi

    Full Text Available Modulation of frontal midline theta (fmθ is observed during error commission, but little is known about the role of theta oscillations in correcting motor behaviours. We investigate EEG activity of healthy partipants executing a reaching task under variable degrees of prism-induced visuo-motor distortion and visual occlusion of the initial arm trajectory. This task introduces directional errors of different magnitudes. The discrepancy between predicted and actual movement directions (i.e. the error, at the time when visual feedback (hand appearance became available, elicits a signal that triggers on-line movement correction. Analysis were performed on 25 EEG channels. For each participant, the median value of the angular error of all reaching trials was used to partition the EEG epochs into high- and low-error conditions. We computed event-related spectral perturbations (ERSP time-locked either to visual feedback or to the onset of movement correction. ERSP time-locked to the onset of visual feedback showed that fmθ increased in the high- but not in the low-error condition with an approximate time lag of 200 ms. Moreover, when single epochs were sorted by the degree of motor error, fmθ started to increase when a certain level of error was exceeded and, then, scaled with error magnitude. When ERSP were time-locked to the onset of movement correction, the fmθ increase anticipated this event with an approximate time lead of 50 ms. During successive trials, an error reduction was observed which was associated with indices of adaptations (i.e., aftereffects suggesting the need to explore if theta oscillations may facilitate learning. To our knowledge this is the first study where the EEG signal recorded during reaching movements was time-locked to the onset of the error visual feedback. This allowed us to conclude that theta oscillations putatively generated by anterior cingulate cortex activation are implicated in error processing in semi

  18. Error Modeling and Experimental Study of a Flexible Joint 6-UPUR Parallel Six-Axis Force Sensor.

    Science.gov (United States)

    Zhao, Yanzhi; Cao, Yachao; Zhang, Caifeng; Zhang, Dan; Zhang, Jie

    2017-09-29

    By combining a parallel mechanism with integrated flexible joints, a large measurement range and high accuracy sensor is realized. However, the main errors of the sensor involve not only assembly errors, but also deformation errors of its flexible leg. Based on a flexible joint 6-UPUR (a kind of mechanism configuration where U-universal joint, P-prismatic joint, R-revolute joint) parallel six-axis force sensor developed during the prephase, assembly and deformation error modeling and analysis of the resulting sensors with a large measurement range and high accuracy are made in this paper. First, an assembly error model is established based on the imaginary kinematic joint method and the Denavit-Hartenberg (D-H) method. Next, a stiffness model is built to solve the stiffness matrix. The deformation error model of the sensor is obtained. Then, the first order kinematic influence coefficient matrix when the synthetic error is taken into account is solved. Finally, measurement and calibration experiments of the sensor composed of the hardware and software system are performed. Forced deformation of the force-measuring platform is detected by using laser interferometry and analyzed to verify the correctness of the synthetic error model. In addition, the first order kinematic influence coefficient matrix in actual circumstances is calculated. By comparing the condition numbers and square norms of the coefficient matrices, the conclusion is drawn theoretically that it is very important to take into account the synthetic error for design stage of the sensor and helpful to improve performance of the sensor in order to meet needs of actual working environments.

  19. Error Modeling and Experimental Study of a Flexible Joint 6-UPUR Parallel Six-Axis Force Sensor

    Directory of Open Access Journals (Sweden)

    Yanzhi Zhao

    2017-09-01

    Full Text Available By combining a parallel mechanism with integrated flexible joints, a large measurement range and high accuracy sensor is realized. However, the main errors of the sensor involve not only assembly errors, but also deformation errors of its flexible leg. Based on a flexible joint 6-UPUR (a kind of mechanism configuration where U-universal joint, P-prismatic joint, R-revolute joint parallel six-axis force sensor developed during the prephase, assembly and deformation error modeling and analysis of the resulting sensors with a large measurement range and high accuracy are made in this paper. First, an assembly error model is established based on the imaginary kinematic joint method and the Denavit-Hartenberg (D-H method. Next, a stiffness model is built to solve the stiffness matrix. The deformation error model of the sensor is obtained. Then, the first order kinematic influence coefficient matrix when the synthetic error is taken into account is solved. Finally, measurement and calibration experiments of the sensor composed of the hardware and software system are performed. Forced deformation of the force-measuring platform is detected by using laser interferometry and analyzed to verify the correctness of the synthetic error model. In addition, the first order kinematic influence coefficient matrix in actual circumstances is calculated. By comparing the condition numbers and square norms of the coefficient matrices, the conclusion is drawn theoretically that it is very important to take into account the synthetic error for design stage of the sensor and helpful to improve performance of the sensor in order to meet needs of actual working environments.

  20. Use of two-part regression calibration model to correct for measurement error in episodically consumed foods in a single-replicate study design: EPIC case study.

    Science.gov (United States)

    Agogo, George O; van der Voet, Hilko; van't Veer, Pieter; Ferrari, Pietro; Leenders, Max; Muller, David C; Sánchez-Cantalejo, Emilio; Bamia, Christina; Braaten, Tonje; Knüppel, Sven; Johansson, Ingegerd; van Eeuwijk, Fred A; Boshuizen, Hendriek

    2014-01-01

    In epidemiologic studies, measurement error in dietary variables often attenuates association between dietary intake and disease occurrence. To adjust for the attenuation caused by error in dietary intake, regression calibration is commonly used. To apply regression calibration, unbiased reference measurements are required. Short-term reference measurements for foods that are not consumed daily contain excess zeroes that pose challenges in the calibration model. We adapted two-part regression calibration model, initially developed for multiple replicates of reference measurements per individual to a single-replicate setting. We showed how to handle excess zero reference measurements by two-step modeling approach, how to explore heteroscedasticity in the consumed amount with variance-mean graph, how to explore nonlinearity with the generalized additive modeling (GAM) and the empirical logit approaches, and how to select covariates in the calibration model. The performance of two-part calibration model was compared with the one-part counterpart. We used vegetable intake and mortality data from European Prospective Investigation on Cancer and Nutrition (EPIC) study. In the EPIC, reference measurements were taken with 24-hour recalls. For each of the three vegetable subgroups assessed separately, correcting for error with an appropriately specified two-part calibration model resulted in about three fold increase in the strength of association with all-cause mortality, as measured by the log hazard ratio. Further found is that the standard way of including covariates in the calibration model can lead to over fitting the two-part calibration model. Moreover, the extent of adjusting for error is influenced by the number and forms of covariates in the calibration model. For episodically consumed foods, we advise researchers to pay special attention to response distribution, nonlinearity, and covariate inclusion in specifying the calibration model.

  1. Common Mechanisms Underlying Refractive Error Identified in Functional Analysis of Gene Lists From Genome-Wide Association Study Results in 2 European British Cohorts

    Science.gov (United States)

    Hysi, Pirro G.; Mahroo, Omar A.; Cumberland, Phillippa; Wojciechowski, Robert; Williams, Katie M.; Young, Terri L.; Mackey, David A.; Rahi, Jugnoo S.; Hammond, Christopher J.

    2014-01-01

    IMPORTANCE To date, relatively few genes responsible for a fraction of heritability have been identified by means of large genetic association studies of refractive error. OBJECTIVE To explore the genetic mechanisms that lead to refractive error in the general population. DESIGN, SETTING, AND PARTICIPANTS Genome-wide association studies were carried out in 2 British population-based independent cohorts (N = 5928 participants) to identify genes moderately associated with refractive error. MAIN OUTCOMES AND MEASURES Enrichment analyses were used to identify sets of genes overrepresented in both cohorts. Enriched groups of genes were compared between both participating cohorts as a further measure against random noise. RESULTS Groups of genes enriched at highly significant statistical levels were remarkably consistent in both cohorts. In particular, these results indicated that plasma membrane (P = 7.64 × 10−30), cell-cell adhesion (P = 2.42 × 10−18), synaptic transmission (P = 2.70 × 10−14), calcium ion binding (P = 3.55 × 10−15), and cation channel activity (P = 2.77 × 10−14) were significantly overrepresented in relation to refractive error. CONCLUSIONS AND RELEVANCE These findings provide evidence that development of refractive error in the general population is related to the intensity of photosignal transduced from the retina, which may have implications for future interventions to minimize this disorder. Pathways connected to the procession of the nerve impulse are major mechanisms involved in the development of refractive error in populations of European origin. PMID:24264139

  2. Medication Errors in Hospitals: A Study of Factors Affecting Nursing Reporting in a Selected Center Affiliated with Shahid Beheshti University of Medical Sciences

    Directory of Open Access Journals (Sweden)

    HamidReza Mirzaee

    2015-10-01

    Full Text Available Background: Medication errors are mentioned as the most common important challenges threatening healthcare system in all countries worldwide. This study is conducted to investigate the most significant factors in refusal to report medication errors among nursing staff.Methods: The cross-sectional study was conducted on all nursing staff of a selected Education& Treatment Center in 2013. Data was collected through a teacher made questionnaire. The questionnaires’ face and content validity was confirmed by experts and for measuring its reliability test-retest was used. Data was analyzed by descriptive and analytic statistics. 16th  version of SPSS was also used for related statistics.Results: The most important factors in refusal to report medication errors respectively are: lack of reporting system in the hospital(3.3%, non-significance of reporting medication errors to hospital authorities and lack of appropriate feedback(3.1%, and lack of a clear definition for a medication error (3%. there was a significant relationship between the most important factors of refusal to report medication errors and work shift (p:0.002, age(p:0.003, gender(p:0.005, work experience(p<0.001 and employment type of nurses(p:0.002.Conclusion: Factors pertaining to management in hospitals as well as the fear of the consequences of reporting are two broad fields among the factors that make nurses not report their medication errors. In this regard, providing enough education to nurses, boosting the job security for nurses, management support and revising related processes and definitions are some factors that can help decreasing medication errors and increasing their report in case of occurrence.

  3. Human Errors in Decision Making

    OpenAIRE

    Mohamad, Shahriari; Aliandrina, Dessy; Feng, Yan

    2005-01-01

    The aim of this paper was to identify human errors in decision making process. The study was focused on a research question such as: what could be the human error as a potential of decision failure in evaluation of the alternatives in the process of decision making. Two case studies were selected from the literature and analyzed to find the human errors contribute to decision fail. Then the analysis of human errors was linked with mental models in evaluation of alternative step. The results o...

  4. Learning curves, taking instructions, and patient safety: using a theoretical domains framework in an interview study to investigate prescribing errors among trainee doctors

    Directory of Open Access Journals (Sweden)

    Duncan Eilidh M

    2012-09-01

    Full Text Available Abstract Background Prescribing errors are a major source of morbidity and mortality and represent a significant patient safety concern. Evidence suggests that trainee doctors are responsible for most prescribing errors. Understanding the factors that influence prescribing behavior may lead to effective interventions to reduce errors. Existing investigations of prescribing errors have been based on Human Error Theory but not on other relevant behavioral theories. The aim of this study was to apply a broad theory-based approach using the Theoretical Domains Framework (TDF to investigate prescribing in the hospital context among a sample of trainee doctors. Method Semistructured interviews, based on 12 theoretical domains, were conducted with 22 trainee doctors to explore views, opinions, and experiences of prescribing and prescribing errors. Content analysis was conducted, followed by applying relevance criteria and a novel stage of critical appraisal, to identify which theoretical domains could be targeted in interventions to improve prescribing. Results Seven theoretical domains met the criteria of relevance: “social professional role and identity,” “environmental context and resources,” “social influences,” “knowledge,” “skills,” “memory, attention, and decision making,” and “behavioral regulation.” From critical appraisal of the interview data, “beliefs about consequences” and “beliefs about capabilities” were also identified as potentially important domains. Interrelationships between domains were evident. Additionally, the data supported theoretical elaboration of the domain behavioral regulation. Conclusions In this investigation of hospital-based prescribing, participants’ attributions about causes of errors were used to identify domains that could be targeted in interventions to improve prescribing. In a departure from previous TDF practice, critical appraisal was used to identify additional domains

  5. Learning curves, taking instructions, and patient safety: using a theoretical domains framework in an interview study to investigate prescribing errors among trainee doctors.

    Science.gov (United States)

    Duncan, Eilidh M; Francis, Jill J; Johnston, Marie; Davey, Peter; Maxwell, Simon; McKay, Gerard A; McLay, James; Ross, Sarah; Ryan, Cristín; Webb, David J; Bond, Christine

    2012-09-11

    Prescribing errors are a major source of morbidity and mortality and represent a significant patient safety concern. Evidence suggests that trainee doctors are responsible for most prescribing errors. Understanding the factors that influence prescribing behavior may lead to effective interventions to reduce errors. Existing investigations of prescribing errors have been based on Human Error Theory but not on other relevant behavioral theories. The aim of this study was to apply a broad theory-based approach using the Theoretical Domains Framework (TDF) to investigate prescribing in the hospital context among a sample of trainee doctors. Semistructured interviews, based on 12 theoretical domains, were conducted with 22 trainee doctors to explore views, opinions, and experiences of prescribing and prescribing errors. Content analysis was conducted, followed by applying relevance criteria and a novel stage of critical appraisal, to identify which theoretical domains could be targeted in interventions to improve prescribing. Seven theoretical domains met the criteria of relevance: "social professional role and identity," "environmental context and resources," "social influences," "knowledge," "skills," "memory, attention, and decision making," and "behavioral regulation." From critical appraisal of the interview data, "beliefs about consequences" and "beliefs about capabilities" were also identified as potentially important domains. Interrelationships between domains were evident. Additionally, the data supported theoretical elaboration of the domain behavioral regulation. In this investigation of hospital-based prescribing, participants' attributions about causes of errors were used to identify domains that could be targeted in interventions to improve prescribing. In a departure from previous TDF practice, critical appraisal was used to identify additional domains that should also be targeted, despite participants' perceptions that they were not relevant to

  6. Nine Loci for Ocular Axial Length Identified through Genome-wide Association Studies, Including Shared Loci with Refractive Error

    Science.gov (United States)

    Cheng, Ching-Yu; Schache, Maria; Ikram, M. Kamran; Young, Terri L.; Guggenheim, Jeremy A.; Vitart, Veronique; MacGregor, Stuart; Verhoeven, Virginie J.M.; Barathi, Veluchamy A.; Liao, Jiemin; Hysi, Pirro G.; Bailey-Wilson, Joan E.; St. Pourcain, Beate; Kemp, John P.; McMahon, George; Timpson, Nicholas J.; Evans, David M.; Montgomery, Grant W.; Mishra, Aniket; Wang, Ya Xing; Wang, Jie Jin; Rochtchina, Elena; Polasek, Ozren; Wright, Alan F.; Amin, Najaf; van Leeuwen, Elisabeth M.; Wilson, James F.; Pennell, Craig E.; van Duijn, Cornelia M.; de Jong, Paulus T.V.M.; Vingerling, Johannes R.; Zhou, Xin; Chen, Peng; Li, Ruoying; Tay, Wan-Ting; Zheng, Yingfeng; Chew, Merwyn; Rahi, Jugnoo S.; Hysi, Pirro G.; Yoshimura, Nagahisa; Yamashiro, Kenji; Miyake, Masahiro; Delcourt, Cécile; Maubaret, Cecilia; Williams, Cathy; Guggenheim, Jeremy A.; Northstone, Kate; Ring, Susan M.; Davey-Smith, George; Craig, Jamie E.; Burdon, Kathryn P.; Fogarty, Rhys D.; Iyengar, Sudha K.; Igo, Robert P.; Chew, Emily; Janmahasathian, Sarayut; Iyengar, Sudha K.; Igo, Robert P.; Chew, Emily; Janmahasathian, Sarayut; Stambolian, Dwight; Wilson, Joan E. Bailey; MacGregor, Stuart; Lu, Yi; Jonas, Jost B.; Xu, Liang; Saw, Seang-Mei; Baird, Paul N.; Rochtchina, Elena; Mitchell, Paul; Wang, Jie Jin; Jonas, Jost B.; Nangia, Vinay; Hayward, Caroline; Wright, Alan F.; Vitart, Veronique; Polasek, Ozren; Campbell, Harry; Vitart, Veronique; Rudan, Igor; Vatavuk, Zoran; Vitart, Veronique; Paterson, Andrew D.; Hosseini, S. Mohsen; Iyengar, Sudha K.; Igo, Robert P.; Fondran, Jeremy R.; Young, Terri L.; Feng, Sheng; Verhoeven, Virginie J.M.; Klaver, Caroline C.; van Duijn, Cornelia M.; Metspalu, Andres; Haller, Toomas; Mihailov, Evelin; Pärssinen, Olavi; Wedenoja, Juho; Wilson, Joan E. Bailey; Wojciechowski, Robert; Baird, Paul N.; Schache, Maria; Pfeiffer, Norbert; Höhn, René; Pang, Chi Pui; Chen, Peng; Meitinger, Thomas; Oexle, Konrad; Wegner, Aharon; Yoshimura, Nagahisa; Yamashiro, Kenji; Miyake, Masahiro; Pärssinen, Olavi; Yip, Shea Ping; Ho, Daniel W.H.; Pirastu, Mario; Murgia, Federico; Portas, Laura; Biino, Genevra; Wilson, James F.; Fleck, Brian; Vitart, Veronique; Stambolian, Dwight; Wilson, Joan E. Bailey; Hewitt, Alex W.; Ang, Wei; Verhoeven, Virginie J.M.; Klaver, Caroline C.; van Duijn, Cornelia M.; Saw, Seang-Mei; Wong, Tien-Yin; Teo, Yik-Ying; Fan, Qiao; Cheng, Ching-Yu; Zhou, Xin; Ikram, M. Kamran; Saw, Seang-Mei; Teo, Yik-Ying; Fan, Qiao; Cheng, Ching-Yu; Zhou, Xin; Ikram, M. Kamran; Saw, Seang-Mei; Wong, Tien-Yin; Teo, Yik-Ying; Fan, Qiao; Cheng, Ching-Yu; Zhou, Xin; Ikram, M. Kamran; Saw, Seang-Mei; Wong, Tien-Yin; Teo, Yik-Ying; Fan, Qiao; Cheng, Ching-Yu; Zhou, Xin; Ikram, M. Kamran; Saw, Seang-Mei; Tai, E-Shyong; Teo, Yik-Ying; Fan, Qiao; Cheng, Ching-Yu; Zhou, Xin; Ikram, M. Kamran; Saw, Seang-Mei; Teo, Yik-Ying; Fan, Qiao; Cheng, Ching-Yu; Zhou, Xin; Ikram, M. Kamran; Mackey, David A.; MacGregor, Stuart; Hammond, Christopher J.; Hysi, Pirro G.; Deangelis, Margaret M.; Morrison, Margaux; Zhou, Xiangtian; Chen, Wei; Paterson, Andrew D.; Hosseini, S. Mohsen; Mizuki, Nobuhisa; Meguro, Akira; Lehtimäki, Terho; Mäkelä, Kari-Matti; Raitakari, Olli; Kähönen, Mika; Burdon, Kathryn P.; Craig, Jamie E.; Iyengar, Sudha K.; Igo, Robert P.; Lass, Jonathan H.; Reinhart, William; Belin, Michael W.; Schultze, Robert L.; Morason, Todd; Sugar, Alan; Mian, Shahzad; Soong, Hunson Kaz; Colby, Kathryn; Jurkunas, Ula; Yee, Richard; Vital, Mark; Alfonso, Eduardo; Karp, Carol; Lee, Yunhee; Yoo, Sonia; Hammersmith, Kristin; Cohen, Elisabeth; Laibson, Peter; Rapuano, Christopher; Ayres, Brandon; Croasdale, Christopher; Caudill, James; Patel, Sanjay; Baratz, Keith; Bourne, William; Maguire, Leo; Sugar, Joel; Tu, Elmer; Djalilian, Ali; Mootha, Vinod; McCulley, James; Bowman, Wayne; Cavanaugh, H. Dwight; Verity, Steven; Verdier, David; Renucci, Ann; Oliva, Matt; Rotkis, Walter; Hardten, David R.; Fahmy, Ahmad; Brown, Marlene; Reeves, Sherman; Davis, Elizabeth A.; Lindstrom, Richard; Hauswirth, Scott; Hamilton, Stephen; Lee, W. Barry; Price, Francis; Price, Marianne; Kelly, Kathleen; Peters, Faye; Shaughnessy, Michael; Steinemann, Thomas; Dupps, B.J.; Meisler, David M.; Mifflin, Mark; Olson, Randal; Aldave, Anthony; Holland, Gary; Mondino, Bartly J.; Rosenwasser, George; Gorovoy, Mark; Dunn, Steven P.; Heidemann, David G.; Terry, Mark; Shamie, Neda; Rosenfeld, Steven I.; Suedekum, Brandon; Hwang, David; Stone, Donald; Chodosh, James; Galentine, Paul G.; Bardenstein, David; Goddard, Katrina; Chin, Hemin; Mannis, Mark; Varma, Rohit; Borecki, Ingrid; Chew, Emily Y.; Haller, Toomas; Mihailov, Evelin; Metspalu, Andres; Wedenoja, Juho; Simpson, Claire L.; Wojciechowski, Robert; Höhn, René; Mirshahi, Alireza; Zeller, Tanja; Pfeiffer, Norbert; Lackner, Karl J.; Donnelly, Peter; Barroso, Ines; Blackwell, Jenefer M.; Bramon, Elvira; Brown, Matthew A.; Casas, Juan P.; Corvin, Aiden; Deloukas, Panos; Duncanson, Audrey; Jankowski, Janusz; Markus, Hugh S.; Mathew, Christopher G.; Palmer, Colin N.A.; Plomin, Robert; Rautanen, Anna; Sawcer, Stephen J.; Trembath, Richard C.; Viswanathan, Ananth C.; Wood, Nicholas W.; Spencer, Chris C.A.; Band, Gavin; Bellenguez, Céline; Freeman, Colin; Hellenthal, Garrett; Giannoulatou, Eleni; Pirinen, Matti; Pearson, Richard; Strange, Amy; Su, Zhan; Vukcevic, Damjan; Donnelly, Peter; Langford, Cordelia; Hunt, Sarah E.; Edkins, Sarah; Gwilliam, Rhian; Blackburn, Hannah; Bumpstead, Suzannah J.; Dronov, Serge; Gillman, Matthew; Gray, Emma; Hammond, Naomi; Jayakumar, Alagurevathi; McCann, Owen T.; Liddle, Jennifer; Potter, Simon C.; Ravindrarajah, Radhi; Ricketts, Michelle; Waller, Matthew; Weston, Paul; Widaa, Sara; Whittaker, Pamela; Barroso, Ines; Deloukas, Panos; Mathew, Christopher G.; Blackwell, Jenefer M.; Brown, Matthew A.; Corvin, Aiden; Spencer, Chris C.A.; Bettecken, Thomas; Meitinger, Thomas; Oexle, Konrad; Pirastu, Mario; Portas, Laura; Nag, Abhishek; Williams, Katie M.; Yonova-Doing, Ekaterina; Klein, Ronald; Klein, Barbara E.; Hosseini, S. Mohsen; Paterson, Andrew D.; Genuth, S.; Nathan, D.M.; Zinman, B.; Crofford, O.; Crandall, J.; Reid, M.; Brown-Friday, J.; Engel, S.; Sheindlin, J.; Martinez, H.; Shamoon, H.; Engel, H.; Phillips, M.; Gubitosi-Klug, R.; Mayer, L.; Pendegast, S.; Zegarra, H.; Miller, D.; Singerman, L.; Smith-Brewer, S.; Novak, M.; Quin, J.; Dahms, W.; Genuth, Saul; Palmert, M.; Brillon, D.; Lackaye, M.E.; Kiss, S.; Chan, R.; Reppucci, V.; Lee, T.; Heinemann, M.; Whitehouse, F.; Kruger, D.; Jones, J.K.; McLellan, M.; Carey, J.D.; Angus, E.; Thomas, A.; Galprin, A.; Bergenstal, R.; Johnson, M.; Spencer, M.; Morgan, K.; Etzwiler, D.; Kendall, D.; Aiello, Lloyd Paul; Golden, E.; Jacobson, A.; Beaser, R.; Ganda, O.; Hamdy, O.; Wolpert, H.; Sharuk, G.; Arrigg, P.; Schlossman, D.; Rosenzwieg, J.; Rand, L.; Nathan, D.M.; Larkin, M.; Ong, M.; Godine, J.; Cagliero, E.; Lou, P.; Folino, K.; Fritz, S.; Crowell, S.; Hansen, K.; Gauthier-Kelly, C.; Service, J.; Ziegler, G.; Luttrell, L.; Caulder, S.; Lopes-Virella, M.; Colwell, J.; Soule, J.; Fernandes, J.; Hermayer, K.; Kwon, S.; Brabham, M.; Blevins, A.; Parker, J.; Lee, D.; Patel, N.; Pittman, C.; Lindsey, P.; Bracey, M.; Lee, K.; Nutaitis, M.; Farr, A.; Elsing, S.; Thompson, T.; Selby, J.; Lyons, T.; Yacoub-Wasef, S.; Szpiech, M.; Wood, D.; Mayfield, R.; Molitch, M.; Schaefer, B.; Jampol, L.; Lyon, A.; Gill, M.; Strugula, Z.; Kaminski, L.; Mirza, R.; Simjanoski, E.; Ryan, D.; Kolterman, O.; Lorenzi, G.; Goldbaum, M.; Sivitz, W.; Bayless, M.; Counts, D.; Johnsonbaugh, S.; Hebdon, M.; Salemi, P.; Liss, R.; Donner, T.; Gordon, J.; Hemady, R.; Kowarski, A.; Ostrowski, D.; Steidl, S.; Jones, B.; Herman, W.H.; Martin, C.L.; Pop-Busui, R.; Sarma, A.; Albers, J.; Feldman, E.; Kim, K.; Elner, S.; Comer, G.; Gardner, T.; Hackel, R.; Prusak, R.; Goings, L.; Smith, A.; Gothrup, J.; Titus, P.; Lee, J.; Brandle, M.; Prosser, L.; Greene, D.A.; Stevens, M.J.; Vine, A.K.; Bantle, J.; Wimmergren, N.; Cochrane, A.; Olsen, T.; Steuer, E.; Rath, P.; Rogness, B.; Hainsworth, D.; Goldstein, D.; Hitt, S.; Giangiacomo, J.; Schade, D.S.; Canady, J.L.; Chapin, J.E.; Ketai, L.H.; Braunstein, C.S.; Bourne, P.A.; Schwartz, S.; Brucker, A.; Maschak-Carey, B.J.; Baker, L.; Orchard, T.; Silvers, N.; Ryan, C.; Songer, T.; Doft, B.; Olson, S.; Bergren, R.L.; Lobes, L.; Rath, P. Paczan; Becker, D.; Rubinstein, D.; Conrad, P.W.; Yalamanchi, S.; Drash, A.; Morrison, A.; Bernal, M.L.; Vaccaro-Kish, J.; Malone, J.; Pavan, P.R.; Grove, N.; Iyer, M.N.; Burrows, A.F.; Tanaka, E.A.; Gstalder, R.; Dagogo-Jack, S.; Wigley, C.; Ricks, H.; Kitabchi, A.; Murphy, M.B.; Moser, S.; Meyer, D.; Iannacone, A.; Chaum, E.; Yoser, S.; Bryer-Ash, M.; Schussler, S.; Lambeth, H.; Raskin, P.; Strowig, S.; Zinman, B.; Barnie, A.; Devenyi, R.; Mandelcorn, M.; Brent, M.; Rogers, S.; Gordon, A.; Palmer, J.; Catton, S.; Brunzell, J.; Wessells, H.; de Boer, I.H.; Hokanson, J.; Purnell, J.; Ginsberg, J.; Kinyoun, J.; Deeb, S.; Weiss, M.; Meekins, G.; Distad, J.; Van Ottingham, L.; Dupre, J.; Harth, J.; Nicolle, D.; Driscoll, M.; Mahon, J.; Canny, C.; May, M.; Lipps, J.; Agarwal, A.; Adkins, T.; Survant, L.; Pate, R.L.; Munn, G.E.; Lorenz, R.; Feman, S.; White, N.; Levandoski, L.; Boniuk, I.; Grand, G.; Thomas, M.; Joseph, D.D.; Blinder, K.; Shah, G.; Boniuk; Burgess; Santiago, J.; Tamborlane, W.; Gatcomb, P.; Stoessel, K.; Taylor, K.; Goldstein, J.; Novella, S.; Mojibian, H.; Cornfeld, D.; Lima, J.; Bluemke, D.; Turkbey, E.; van der Geest, R.J.; Liu, C.; Malayeri, A.; Jain, A.; Miao, C.; Chahal, H.; Jarboe, R.; Maynard, J.; Gubitosi-Klug, R.; Quin, J.; Gaston, P.; Palmert, M.; Trail, R.; Dahms, W.; Lachin, J.; Cleary, P.; Backlund, J.; Sun, W.; Braffett, B.; Klumpp, K.; Chan, K.; Diminick, L.; Rosenberg, D.; Petty, B.; Determan, A.; Kenny, D.; Rutledge, B.; Younes, Naji; Dews, L.; Hawkins, M.; Cowie, C.; Fradkin, J.; Siebert, C.; Eastman, R.; Danis, R.; Gangaputra, S.; Neill, S.; Davis, M.; Hubbard, L.; Wabers, H.; Burger, M.; Dingledine, J.; Gama, V.; Sussman, R.; Steffes, M.; Bucksa, J.; Nowicki, M.; Chavers, B.; O’Leary, D.; Polak, J.; Harrington, A.; Funk, L.; Crow, R.; Gloeb, B.; Thomas, S.; O’Donnell, C.; Soliman, E.; Zhang, Z.M.; Prineas, R.; Campbell, C.; Ryan, C.; Sandstrom, D.; Williams, T.; Geckle, M.; Cupelli, E.; Thoma, F.; Burzuk, B.; Woodfill, T.; Low, P.; Sommer, C.; Nickander, K.; Budoff, M.; Detrano, R.; Wong, N.; Fox, M.; Kim, L.; Oudiz, R.; Weir, G.; Espeland, M.; Manolio, T.; Rand, L.; Singer, D.; Stern, M.; Boulton, A.E.; Clark, C.; D’Agostino, R.; Lopes-Virella, M.; Garvey, W.T.; Lyons, T.J.; Jenkins, A.; Virella, G.; Jaffa, A.; Carter, Rickey; Lackland, D.; Brabham, M.; McGee, D.; Zheng, D.; Mayfield, R.K.; Boright, A.; Bull, S.; Sun, L.; Scherer, S.; Zinman, B.; Natarajan, R.; Miao, F.; Zhang, L.; Chen;, Z.; Nathan, D.M.; Makela, Kari-Matti; Lehtimaki, Terho; Kahonen, Mika; Raitakari, Olli; Yoshimura, Nagahisa; Matsuda, Fumihiko; Chen, Li Jia; Pang, Chi Pui; Yip, Shea Ping; Yap, Maurice K.H.; Meguro, Akira; Mizuki, Nobuhisa; Inoko, Hidetoshi; Foster, Paul J.; Zhao, Jing Hua; Vithana, Eranga; Tai, E-Shyong; Fan, Qiao; Xu, Liang; Campbell, Harry; Fleck, Brian; Rudan, Igor; Aung, Tin; Hofman, Albert; Uitterlinden, André G.; Bencic, Goran; Khor, Chiea-Chuen; Forward, Hannah; Pärssinen, Olavi; Mitchell, Paul; Rivadeneira, Fernando; Hewitt, Alex W.; Williams, Cathy; Oostra, Ben A.; Teo, Yik-Ying; Hammond, Christopher J.; Stambolian, Dwight; Mackey, David A.; Klaver, Caroline C.W.; Wong, Tien-Yin; Saw, Seang-Mei; Baird, Paul N.

    2013-01-01

    Refractive errors are common eye disorders of public health importance worldwide. Ocular axial length (AL) is the major determinant of refraction and thus of myopia and hyperopia. We conducted a meta-analysis of genome-wide association studies for AL, combining 12,531 Europeans and 8,216 Asians. We identified eight genome-wide significant loci for AL (RSPO1, C3orf26, LAMA2, GJD2, ZNRF3, CD55, MIP, and ALPPL2) and confirmed one previously reported AL locus (ZC3H11B). Of the nine loci, five (LAMA2, GJD2, CD55, ALPPL2, and ZC3H11B) were associated with refraction in 18 independent cohorts (n = 23,591). Differential gene expression was observed for these loci in minus-lens-induced myopia mouse experiments and human ocular tissues. Two of the AL genes, RSPO1 and ZNRF3, are involved in Wnt signaling, a pathway playing a major role in the regulation of eyeball size. This study provides evidence of shared genes between AL and refraction, but importantly also suggests that these traits may have unique pathways. PMID:24144296

  7. Study of the Ultimate Error of the Axis Tolerance Feature and Its Pose Decoupling Based on an Area Coordinate System

    Directory of Open Access Journals (Sweden)

    Qungui Du

    2018-03-01

    Full Text Available Manufacturing error and assembly error should be taken into consideration during evaluation and analysis of accurate product performance in the design phase. Traditional tolerance analysis methods establish error propagation model based on dimension chains with tolerance values being regarded as error boundaries, and obtain the limit of target feature error through optimization methods or conducting statistical analysis with the tolerance domain being the boundary. As deviations of the tolerance feature (TF on degrees of freedom (DOF have coupling relations, accurate deviations on all DOF may not be obtained, even though these deviations constitute the basis for product performance analysis. Therefore, taking the widely used shaft-hole fit as an example, a pose decoupling model of the axis TF was proposed based on an area coordinate system. This model realized decoupling analysis of any pose of the axis TF within the tolerance domain. As proposed by the authors, by combining a tolerance analysis model based on tracking local coordinate systems, ultimate pose analysis of the closed-loop system, namely the target feature, as well as statistical analysis could be further implemented. This method contributed to analysis of true product performance with arbitrary error in the product design phase from the angle of tolerance, therefore, shortening the product research and development cycle. This method is demonstrated through applying it to a real-life example.

  8. A comparison of medication administration errors from original medication packaging and multi-compartment compliance aids in care homes: A prospective observational study.

    Science.gov (United States)

    Gilmartin-Thomas, Julia Fiona-Maree; Smith, Felicity; Wolfe, Rory; Jani, Yogini

    2017-07-01

    No published study has been specifically designed to compare medication administration errors between original medication packaging and multi-compartment compliance aids in care homes, using direct observation. Compare the effect of original medication packaging and multi-compartment compliance aids on medication administration accuracy. Prospective observational. Ten Greater London care homes. Nurses and carers administering medications. Between October 2014 and June 2015, a pharmacist researcher directly observed solid, orally administered medications in tablet or capsule form at ten purposively sampled care homes (five only used original medication packaging and five used both multi-compartment compliance aids and original medication packaging). The medication administration error rate was calculated as the number of observed doses administered (or omitted) in error according to medication administration records, compared to the opportunities for error (total number of observed doses plus omitted doses). Over 108.4h, 41 different staff (35 nurses, 6 carers) were observed to administer medications to 823 residents during 90 medication administration rounds. A total of 2452 medication doses were observed (1385 from original medication packaging, 1067 from multi-compartment compliance aids). One hundred and seventy eight medication administration errors were identified from 2493 opportunities for error (7.1% overall medication administration error rate). A greater medication administration error rate was seen for original medication packaging than multi-compartment compliance aids (9.3% and 3.1% respectively, risk ratio (RR)=3.9, 95% confidence interval (CI) 2.4 to 6.1, ppackaging (from original medication packaging-only care homes) and multi-compartment compliance aids (RR=2.3, 95%CI 1.1 to 4.9, p=0.03), and between original medication packaging and multi-compartment compliance aids within care homes that used a combination of both medication administration

  9. A multiobserver study of the effects of including point-of-care patient photographs with portable radiography: a means to detect wrong-patient errors.

    Science.gov (United States)

    Tridandapani, Srini; Ramamurthy, Senthil; Provenzale, James; Obuchowski, Nancy A; Evanoff, Michael G; Bhatti, Pamela

    2014-08-01

    To evaluate whether the presence of facial photographs obtained at the point-of-care of portable radiography leads to increased detection of wrong-patient errors. In this institutional review board-approved study, 166 radiograph-photograph combinations were obtained from 30 patients. Consecutive radiographs from the same patients resulted in 83 unique pairs (ie, a new radiograph and prior, comparison radiograph) for interpretation. To simulate wrong-patient errors, mismatched pairs were generated by pairing radiographs from different patients chosen randomly from the sample. Ninety radiologists each interpreted a unique randomly chosen set of 10 radiographic pairs, containing up to 10% mismatches (ie, error pairs). Radiologists were randomly assigned to interpret radiographs with or without photographs. The number of mismatches was identified, and interpretation times were recorded. Ninety radiologists with 21 ± 10 (mean ± standard deviation) years of experience were recruited to participate in this observer study. With the introduction of photographs, the proportion of errors detected increased from 31% (9 of 29) to 77% (23 of 30; P = .006). The odds ratio for detection of error with photographs to detection without photographs was 7.3 (95% confidence interval: 2.29-23.18). Observer qualifications, training, or practice in cardiothoracic radiology did not influence sensitivity for error detection. There is no significant difference in interpretation time for studies without photographs and those with photographs (60 ± 22 vs. 61 ± 25 seconds; P = .77). In this observer study, facial photographs obtained simultaneously with portable chest radiographs increased the identification of any wrong-patient errors, without substantial increase in interpretation time. This technique offers a potential means to increase patient safety through correct patient identification. Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.

  10. Application of a repeat-measure biomarker measurement error model to 2 validation studies: examination of the effect of within-person variation in biomarker measurements.

    Science.gov (United States)

    Preis, Sarah Rosner; Spiegelman, Donna; Zhao, Barbara Bojuan; Moshfegh, Alanna; Baer, David J; Willett, Walter C

    2011-03-15

    Repeat-biomarker measurement error models accounting for systematic correlated within-person error can be used to estimate the correlation coefficient (ρ) and deattenuation factor (λ), used in measurement error correction. These models account for correlated errors in the food frequency questionnaire (FFQ) and the 24-hour diet recall and random within-person variation in the biomarkers. Failure to account for within-person variation in biomarkers can exaggerate correlated errors between FFQs and 24-hour diet recalls. For 2 validation studies, ρ and λ were calculated for total energy and protein density. In the Automated Multiple-Pass Method Validation Study (n=471), doubly labeled water (DLW) and urinary nitrogen (UN) were measured twice in 52 adults approximately 16 months apart (2002-2003), yielding intraclass correlation coefficients of 0.43 for energy (DLW) and 0.54 for protein density (UN/DLW). The deattenuated correlation coefficient for protein density was 0.51 for correlation between the FFQ and the 24-hour diet recall and 0.49 for correlation between the FFQ and the biomarker. Use of repeat-biomarker measurement error models resulted in a ρ of 0.42. These models were similarly applied to the Observing Protein and Energy Nutrition Study (1999-2000). In conclusion, within-person variation in biomarkers can be substantial, and to adequately assess the impact of correlated subject-specific error, this variation should be assessed in validation studies of FFQs. © The Author 2011. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved.

  11. Error analysis of equilibrium studies for the almond shell activated carbon adsorption of Cr(VI) from aqueous solutions

    International Nuclear Information System (INIS)

    Demirbas, E.; Kobya, M.; Konukman, A.E.S.

    2008-01-01

    In this study, the preparation of activated carbon from almond shell with H 2 SO 4 activation and its ability to remove toxic hexavalent chromium from aqueous solutions are reported. The influences of several operating parameters such as pH, particle size and temperature on the adsorption capacity were investigated. Adsorption of Cr(VI) is found to be highly pH, particle size and temperature dependent. Four adsorption isotherm models namely, Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich were used to analyze the equilibrium data. The Langmuir isotherm provided the best correlation for Cr(VI) onto the almond shell activated carbon (ASC). Adsorption capacity was calculated from the Langmuir isotherm as 190.3 mg/g at 323 K. Thermodynamic parameters were evaluated and the adsorption was endothermic showing monolayer adsorption of Cr(VI). Five error functions were used to treat the equilibrium data using non-linear optimization techniques for evaluating the fit of the isotherm equations. The highest correlation for the isotherm equations in this system was obtained for the Freundlich isotherm. ASC is found to be inexpensive and effective adsorbent for removal of Cr(VI) from aqueous solutions

  12. Design of robust adaptive controller and feedback error learning for rehabilitation in Parkinson's disease: a simulation study.

    Science.gov (United States)

    Rouhollahi, Korosh; Emadi Andani, Mehran; Karbassi, Seyed Mahdi; Izadi, Iman

    2017-02-01

    Deep brain stimulation (DBS) is an efficient therapy to control movement disorders of Parkinson's tremor. Stimulation of one area of basal ganglia (BG) by DBS with no feedback is the prevalent opinion. Reduction of additional stimulatory signal delivered to the brain is the advantage of using feedback. This results in reduction of side effects caused by the excessive stimulation intensity. In fact, the stimulatory intensity of controllers is decreased proportional to reduction of hand tremor. The objective of this study is to design a new controller structure to decrease three indicators: (i) the hand tremor; (ii) the level of delivered stimulation in disease condition; and (iii) the ratio of the level of delivered stimulation in health condition to disease condition. For this purpose, the authors offer a new closed-loop control structure to stimulate two areas of BG simultaneously. One area (STN: subthalamic nucleus) is stimulated by an adaptive controller with feedback error learning. The other area (GPi: globus pallidus internal) is stimulated by a partial state feedback (PSF) controller. Considering the three indicators, the results show that, stimulating two areas simultaneously leads to better performance compared with stimulating one area only. It is shown that both PSF and adaptive controllers are robust regarding system parameter uncertainties. In addition, a method is proposed to update the parameters of the BG model in real time. As a result, the parameters of the controllers can be updated based on the new parameters of the BG model.

  13. Learning from prescribing errors

    OpenAIRE

    Dean, B

    2002-01-01

    

 The importance of learning from medical error has recently received increasing emphasis. This paper focuses on prescribing errors and argues that, while learning from prescribing errors is a laudable goal, there are currently barriers that can prevent this occurring. Learning from errors can take place on an individual level, at a team level, and across an organisation. Barriers to learning from prescribing errors include the non-discovery of many prescribing errors, lack of feedback to th...

  14. Accurate recapture identification for genetic mark–recapture studies with error-tolerant likelihood-based match calling and sample clustering

    Science.gov (United States)

    Sethi, Suresh; Linden, Daniel; Wenburg, John; Lewis, Cara; Lemons, Patrick R.; Fuller, Angela K.; Hare, Matthew P.

    2016-01-01

    Error-tolerant likelihood-based match calling presents a promising technique to accurately identify recapture events in genetic mark–recapture studies by combining probabilities of latent genotypes and probabilities of observed genotypes, which may contain genotyping errors. Combined with clustering algorithms to group samples into sets of recaptures based upon pairwise match calls, these tools can be used to reconstruct accurate capture histories for mark–recapture modelling. Here, we assess the performance of a recently introduced error-tolerant likelihood-based match-calling model and sample clustering algorithm for genetic mark–recapture studies. We assessed both biallelic (i.e. single nucleotide polymorphisms; SNP) and multiallelic (i.e. microsatellite; MSAT) markers using a combination of simulation analyses and case study data on Pacific walrus (Odobenus rosmarus divergens) and fishers (Pekania pennanti). A novel two-stage clustering approach is demonstrated for genetic mark–recapture applications. First, repeat captures within a sampling occasion are identified. Subsequently, recaptures across sampling occasions are identified. The likelihood-based matching protocol performed well in simulation trials, demonstrating utility for use in a wide range of genetic mark–recapture studies. Moderately sized SNP (64+) and MSAT (10–15) panels produced accurate match calls for recaptures and accurate non-match calls for samples from closely related individuals in the face of low to moderate genotyping error. Furthermore, matching performance remained stable or increased as the number of genetic markers increased, genotyping error notwithstanding.

  15. Heuristic errors in clinical reasoning.

    Science.gov (United States)

    Rylander, Melanie; Guerrasio, Jeannette

    2016-08-01

    Errors in clinical reasoning contribute to patient morbidity and mortality. The purpose of this study was to determine the types of heuristic errors made by third-year medical students and first-year residents. This study surveyed approximately 150 clinical educators inquiring about the types of heuristic errors they observed in third-year medical students and first-year residents. Anchoring and premature closure were the two most common errors observed amongst third-year medical students and first-year residents. There was no difference in the types of errors observed in the two groups. Errors in clinical reasoning contribute to patient morbidity and mortality Clinical educators perceived that both third-year medical students and first-year residents committed similar heuristic errors, implying that additional medical knowledge and clinical experience do not affect the types of heuristic errors made. Further work is needed to help identify methods that can be used to reduce heuristic errors early in a clinician's education. © 2015 John Wiley & Sons Ltd.

  16. Laboratory errors and patient safety.

    Science.gov (United States)

    Miligy, Dawlat A

    2015-01-01

    Laboratory data are extensively used in medical practice; consequently, laboratory errors have a tremendous impact on patient safety. Therefore, programs designed to identify and reduce laboratory errors, as well as, setting specific strategies are required to minimize these errors and improve patient safety. The purpose of this paper is to identify part of the commonly encountered laboratory errors throughout our practice in laboratory work, their hazards on patient health care and some measures and recommendations to minimize or to eliminate these errors. Recording the encountered laboratory errors during May 2008 and their statistical evaluation (using simple percent distribution) have been done in the department of laboratory of one of the private hospitals in Egypt. Errors have been classified according to the laboratory phases and according to their implication on patient health. Data obtained out of 1,600 testing procedure revealed that the total number of encountered errors is 14 tests (0.87 percent of total testing procedures). Most of the encountered errors lay in the pre- and post-analytic phases of testing cycle (representing 35.7 and 50 percent, respectively, of total errors). While the number of test errors encountered in the analytic phase represented only 14.3 percent of total errors. About 85.7 percent of total errors were of non-significant implication on patients health being detected before test reports have been submitted to the patients. On the other hand, the number of test errors that have been already submitted to patients and reach the physician represented 14.3 percent of total errors. Only 7.1 percent of the errors could have an impact on patient diagnosis. The findings of this study were concomitant with those published from the USA and other countries. This proves that laboratory problems are universal and need general standardization and bench marking measures. Original being the first data published from Arabic countries that

  17. An empirical study on the basic human error probabilities for NPP advanced main control room operation using soft control

    International Nuclear Information System (INIS)

    Jang, Inseok; Kim, Ar Ryum; Harbi, Mohamed Ali Salem Al; Lee, Seung Jun; Kang, Hyun Gook; Seong, Poong Hyun

    2013-01-01

    Highlights: ► The operation environment of MCRs in NPPs has changed by adopting new HSIs. ► The operation action in NPP Advanced MCRs is performed by soft control. ► Different basic human error probabilities (BHEPs) should be considered. ► BHEPs in a soft control operation environment are investigated empirically. ► This work will be helpful to verify if soft control has positive or negative effects. -- Abstract: By adopting new human–system interfaces that are based on computer-based technologies, the operation environment of main control rooms (MCRs) in nuclear power plants (NPPs) has changed. The MCRs that include these digital and computer technologies, such as large display panels, computerized procedures, soft controls, and so on, are called Advanced MCRs. Among the many features in Advanced MCRs, soft controls are an important feature because the operation action in NPP Advanced MCRs is performed by soft control. Using soft controls such as mouse control, touch screens, and so on, operators can select a specific screen, then choose the controller, and finally manipulate the devices. However, because of the different interfaces between soft control and hardwired conventional type control, different basic human error probabilities (BHEPs) should be considered in the Human Reliability Analysis (HRA) for advanced MCRs. Although there are many HRA methods to assess human reliabilities, such as Technique for Human Error Rate Prediction (THERP), Accident Sequence Evaluation Program (ASEP), Human Error Assessment and Reduction Technique (HEART), Human Event Repository and Analysis (HERA), Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR), Cognitive Reliability and Error Analysis Method (CREAM), and so on, these methods have been applied to conventional MCRs, and they do not consider the new features of advance MCRs such as soft controls. As a result, there is an insufficient database for assessing human reliabilities in advanced

  18. A Preliminary Study on the Measures to Assess the Organizational Safety: The Cultural Impact on Human Error Potential

    International Nuclear Information System (INIS)

    Lee, Yong Hee; Lee, Yong Hee

    2011-01-01

    The Fukushima I nuclear accident following the Tohoku earthquake and tsunami on 11 March 2011 occurred after twelve years had passed since the JCO accident which was caused as a result of an error made by JCO employees. These accidents, along with the Chernobyl accident, associated with characteristic problems of various organizations caused severe social and economic disruptions and have had significant environmental and health impact. The cultural problems with human errors occur for various reasons, and different actions are needed to prevent different errors. Unfortunately, much of the research on organization and human error has shown widely various or different results which call for different approaches. In other words, we have to find more practical solutions from various researches for nuclear safety and lead a systematic approach to organizational deficiency causing human error. This paper reviews Hofstede's criteria, IAEA safety culture, safety areas of periodic safety review (PSR), teamwork and performance, and an evaluation of HANARO safety culture to verify the measures used to assess the organizational safety

  19. Somatotopic mapping of piano fingering errors in sensorimotor experts: TMS studies in pianists and visually trained musically naives.

    Science.gov (United States)

    Candidi, Matteo; Sacheli, Lucia Maria; Mega, Ilaria; Aglioti, Salvatore Maria

    2014-02-01

    Virtuosic musical performance requires fine sensorimotor skills and high predictive control of the fast finger movements that produce the intended sounds, and cannot be corrected once the notes have been played. The anticipatory nature of motor control in experts explains why musical performance is barely affected by auditory feedback. Using single-pulse transcranial magnetic stimulation, we provide evidence that, in expert pianists (Experiment 1), the observation of a mute piano fingering error induces 1) a time-locked facilitation of hand corticospinal representation which occurred 300 and 700 ms but not 100 ms after error onset, and 2) a somatotopic corticospinal facilitation of the very same finger that commits the error. In a second experiment, we show that no corticospinal modulation is found in non-pianist naïve individuals who were experimentally trained to visually detect the observed fingering errors (Experiment 2). This is the first evidence showing that the refined somatosensory and motor skills of musicians exceed the domain of individual motor control and may provide the brain with fine anticipatory, simulative error monitoring systems for the evaluation of others' movements.

  20. A Preliminary Study on the Measures to Assess the Organizational Safety: The Cultural Impact on Human Error Potential

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Hee; Lee, Yong Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-10-15

    The Fukushima I nuclear accident following the Tohoku earthquake and tsunami on 11 March 2011 occurred after twelve years had passed since the JCO accident which was caused as a result of an error made by JCO employees. These accidents, along with the Chernobyl accident, associated with characteristic problems of various organizations caused severe social and economic disruptions and have had significant environmental and health impact. The cultural problems with human errors occur for various reasons, and different actions are needed to prevent different errors. Unfortunately, much of the research on organization and human error has shown widely various or different results which call for different approaches. In other words, we have to find more practical solutions from various researches for nuclear safety and lead a systematic approach to organizational deficiency causing human error. This paper reviews Hofstede's criteria, IAEA safety culture, safety areas of periodic safety review (PSR), teamwork and performance, and an evaluation of HANARO safety culture to verify the measures used to assess the organizational safety

  1. A Sensitivity Study of Human Errors in Optimizing Surveillance Test Interval (STI) and Allowed Outage Time (AOT) of Standby Safety System

    International Nuclear Information System (INIS)

    Chung, Dae Wook; Shin, Won Ky; You, Young Woo; Yang, Hui Chang

    1998-01-01

    In most cases, the surveillance test intervals (STIs), allowed outage times (AOTS) and testing strategies of safety components in nuclear power plant are prescribed in plant technical specifications. And, in general, it is required that standby safety system shall be redundant (i.e., composed of multiple components) and these components are tested by either staggered test strategy or sequential test strategy. In this study, a linear model is presented to incorporate the effects of human errors associated with test into the evaluation of unavailability. The average unavailabilities of 1/4, 2/4 redundant systems are computed considering human error and testing strategy. The adverse effects of test on system unavailability, such as component wear and test-induced transient have been modelled. The final outcome of this study would be the optimized human error domain from 3-D human error sensitivity analysis by selecting finely classified segment. The results of sensitivity analysis show that the STI and AOT can be optimized provided human error probability is maintained within allowable range. (authors)

  2. The preliminary study of setup errors' impact on dose distribution of image guide radiation therapy for head and neck cancer

    International Nuclear Information System (INIS)

    Xu Luying; Pan Jianji; Wang Xiaoliang; Bai Penggang; Li Qixin; Fei Zhaodong; Chen Chuanben; Ma Liqin; Tang Tianlan

    2011-01-01

    Objective: To measure the set-up errors of patients with head and neck (H and N) cancer during the image guided intensity-modulated radiotherapy (IMRT) treatment and analyze the impact of setup errors on dose distribution; then to further investigate the necessity of adjustment online for H and N cancer during IMRT treatment. Methods: Cone-beam CT (CBCT) scanning of thirty patients with H and N cancer were acquired by once weekly with a total of 6 times during IMRT treatment. The CBCT images and the original planning CT images were matched by the bony structure and worked out the translational errors of the x, y, z axis, as well as rotational errors. The dose distributions were recalculated based on the data of each setup error. The dose of planning target volume (PTV) and organs at risk were calculated in the re-planning, and than compared with the original plan by paired t-test. Results: The mean value of x, y, z axis translational set-up errors were (1.06 ± 0.95)mm, (0.95 ± 0.77)mm and (1.31 ± 1.07)mm, respectively. The rotational error of x, y, z axis were (1.04 ±0.791), (1.06 ±0.89) and (0.81 ±0.61 ), respectively. PTV 95% volume dose (D 95 ) and PTV minimal dose of re-planning for 6 times set-up were lower than original plan (6526.6 cGy : 6630.3 cGy, t =3.98, P =0.000 and 5632.6 cGy : 5792.5 cGy, t =- 2.89, P =0.007). Brain stem received 45 Gydose volume (V 45 ) and 1% brain stem volume dose (D 01 )were higher than original plan (3.54% : 2.75%, t =3.84, P =0.001 and 5129.7 cGy : 4919.3 cGy, t =4.36, P =0.000). Conclusions: The set-up errors led to the dose of PTV D 95 obviously insufficient and significantly increased V 45 , D 01 of the brainstem. So, adjustment online is necessary for H and N cancer during IMRT treatment. (authors)

  3. Individual and Contextual Factors Influencing Engagement in Learning Activities after Errors at Work: A Replication Study in a German Retail Bank

    Science.gov (United States)

    Leicher, Veronika; Mulder, Regina H.

    2016-01-01

    Purpose: The purpose of this replication study is to identify relevant individual and contextual factors influencing learning from errors at work and to determine if the predictors for learning activities are the same for the domains of nursing and retail banking. Design/methodology/approach: A cross-sectional replication study was carried out in…

  4. An Analysis of Errors Committed by Saudi Non-English Major Students in the English Paragraph Writing: A Study of Comparisons

    Science.gov (United States)

    Nuruzzaman, Mohammed; Islam, A. B. M. Shafiqul; Shuchi, Israt Jahan

    2018-01-01

    The present study investigates the writing errors of ninety Saudi non-English major undergraduate students of different proficiency levels from three faculties, who studied English as a foundation course at the English Language Center in the College of Languages &Translation at King Khalid University, Saudi Arabia in the academic year 2016-17.…

  5. Error-correction coding

    Science.gov (United States)

    Hinds, Erold W. (Principal Investigator)

    1996-01-01

    This report describes the progress made towards the completion of a specific task on error-correcting coding. The proposed research consisted of investigating the use of modulation block codes as the inner code of a concatenated coding system in order to improve the overall space link communications performance. The study proposed to identify and analyze candidate codes that will complement the performance of the overall coding system which uses the interleaved RS (255,223) code as the outer code.

  6. A study of total measurement error in tomographic gamma scanning to assay nuclear material with emphasis on a bias issue for low-activity samples

    International Nuclear Information System (INIS)

    Burr, T.L.; Mercer, D.J.; Prettyman, T.H.

    1998-01-01

    Field experience with the tomographic gamma scanner to assay nuclear material suggests that the analysis techniques can significantly impact the assay uncertainty. For example, currently implemented image reconstruction methods exhibit a positive bias for low-activity samples. Preliminary studies indicate that bias reduction could be achieved at the expense of increased random error variance. In this paper, the authors examine three possible bias sources: (1) measurement error in the estimated transmission matrix, (2) the positivity constraint on the estimated mass of nuclear material, and (3) improper treatment of the measurement error structure. The authors present results from many small-scale simulation studies to examine this bias/variance tradeoff for a few image reconstruction methods in the presence of the three possible bias sources

  7. CORRELATION OF FUNDUS CHANGES IN RELATION TO REFRACTIVE ERROR IN PATIENTS WITH MYOPIA- A CLINICAL PROSPECTIVE STUDY

    Directory of Open Access Journals (Sweden)

    Balasubramanian M. Manickavelu

    2018-01-01

    Full Text Available BACKGROUND Retina is unique among the complex element of the central nervous system and the special senses. It may be readily viewed during life and it is sufficiently transparent, so that alterations within and adjacent to it may be observed in vivo. The peripheral retina owing to its thinness comparing to that of the central part, poorly-developed retinal cells, absence of large blood vessels, relatively insensitive to light, less resistance to traction, forms a seat for various lesions, which are potentially dangerous for the vision. It is in myopia that we meet the most frequent and the most obvious anomalies in the fundus changes, which bear some relation to the degree of myopia and appeal to be concerned with it either as a cause or effect or perhaps both. The aim of our study is to correlate fundus changes in relation to refractive error in patients with myopia. MATERIALS AND METHODS In our study, 100 cases of myopic (-6D:50 cases patients were selected. Detailed evaluation done. History of refractive error includes duration, age at which spectacles were worn for the first time. Time of last change of spectacles, family history of myopia, history of other symptoms like progressive loss of vision, defective vision related to day or night, sudden loss of vision, flashes and floaters. Anterior segment was examined followed by the recording of initial visual acuity and the best corrected visual acuity was noted. IOP was measured for all the cases using Schiotz tonometry. Axial length was measured in all the cases. Fundus examined with direct ophthalmoscope, indirect ophthalmoscope, 3 mirror and 90D lens. Bscan was done in few cases. The media, disc, vessels, macula and the surrounding retina were examined. The periphery was examined with indentation method. The various fundus features and pathological lesions in different degrees of myopia were noted. RESULTS Females were comparatively more affected. Highest incidence was seen in the younger

  8. Barriers to medical error reporting

    Directory of Open Access Journals (Sweden)

    Jalal Poorolajal

    2015-01-01

    Full Text Available Background: This study was conducted to explore the prevalence of medical error underreporting and associated barriers. Methods: This cross-sectional study was performed from September to December 2012. Five hospitals, affiliated with Hamadan University of Medical Sciences, in Hamedan,Iran were investigated. A self-administered questionnaire was used for data collection. Participants consisted of physicians, nurses, midwives, residents, interns, and staffs of radiology and laboratory departments. Results: Overall, 50.26% of subjects had committed but not reported medical errors. The main reasons mentioned for underreporting were lack of effective medical error reporting system (60.0%, lack of proper reporting form (51.8%, lack of peer supporting a person who has committed an error (56.0%, and lack of personal attention to the importance of medical errors (62.9%. The rate of committing medical errors was higher in men (71.4%, age of 50-40 years (67.6%, less-experienced personnel (58.7%, educational level of MSc (87.5%, and staff of radiology department (88.9%. Conclusions: This study outlined the main barriers to reporting medical errors and associated factors that may be helpful for healthcare organizations in improving medical error reporting as an essential component for patient safety enhancement.

  9. Two-dimensional errors

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    This chapter addresses the extension of previous work in one-dimensional (linear) error theory to two-dimensional error analysis. The topics of the chapter include the definition of two-dimensional error, the probability ellipse, the probability circle, elliptical (circular) error evaluation, the application to position accuracy, and the use of control systems (points) in measurements

  10. Part two: Error propagation

    International Nuclear Information System (INIS)

    Picard, R.R.

    1989-01-01

    Topics covered in this chapter include a discussion of exact results as related to nuclear materials management and accounting in nuclear facilities; propagation of error for a single measured value; propagation of error for several measured values; error propagation for materials balances; and an application of error propagation to an example of uranium hexafluoride conversion process

  11. Learning from Errors

    OpenAIRE

    Martínez-Legaz, Juan Enrique; Soubeyran, Antoine

    2003-01-01

    We present a model of learning in which agents learn from errors. If an action turns out to be an error, the agent rejects not only that action but also neighboring actions. We find that, keeping memory of his errors, under mild assumptions an acceptable solution is asymptotically reached. Moreover, one can take advantage of big errors for a faster learning.

  12. A study on the critical factors of human error in civil aviation: An early warning management perspective in Bangladesh

    Directory of Open Access Journals (Sweden)

    Md. Salah Uddin Rajib

    2015-01-01

    Full Text Available The safety of civil aviation will be more secured if the errors in all the facets can be reduced. Like the other industrial sectors, human resource is one of the most complex and sensitive resources for the civil aviation. The error of human resources can cause fatal disasters. In these days, a good volume of researches have been conducted on the disaster of civil aviation. The researchers have identified the causes of the civil aviation disasters from various perspectives. They identified the areas where more concern is needed to reduce the disastrous impacts. This paper aims to find out the critical factors of human error in civil aviation in a developing country (Bangladesh as it is accepted that human error is one of main causes of civil aviation disasters. The paper reviews the previous research to find out the critical factors conceptually. Fuzzy analytical hierarchy process (FAHP has been used to find out the critical factors systematically. Analyses indicate that the concentration on precondition for unsafe acts (including sub-factors is required to ensure the aviation safety.

  13. Association Between Workarounds and Medication Administration Errors in Bar Code-Assisted Medication Administration : Protocol of a Multicenter Study

    NARCIS (Netherlands)

    van der Veen, Willem; van den Bemt, Patricia Mla; Bijlsma, Maarten; de Gier, Han J; Taxis, Katja

    2017-01-01

    BACKGROUND: Information technology-based methods such as bar code-assisted medication administration (BCMA) systems have the potential to reduce medication administration errors (MAEs) in hospitalized patients. In practice, however, systems are often not used as intended, leading to workarounds.

  14. Can the error detection mechanism benefit from training the working memory? A comparison between dyslexics and controls--an ERP study.

    Directory of Open Access Journals (Sweden)

    Tzipi Horowitz-Kraus

    Full Text Available BACKGROUND: Based on the relationship between working memory and error detection, we investigated the capacity of adult dyslexic readers' working memory to change as a result of training, and the impact of training on the error detection mechanism. METHODOLOGY: 27 dyslexics and 34 controls, all university students, participated in the study. ERP methodology and behavioral measures were employed prior to, immediately after, and 6 months after training. The CogniFit Personal Coach Program, which consists of 24 sessions of direct training of working memory skills, was used. FINDINGS: Both groups of readers gained from the training program but the dyslexic readers gained significantly more. In the dyslexic group, digit span increased from 9.84+/-3.15 to 10.79+/-3.03. Working memory training significantly increased the number of words per minute read correctly by 14.73%. Adult brain activity changed as a result of training, evidenced by an increase in both working memory capacity and the amplitude of the Error-related Negativity (ERN component (24.71%. When ERN amplitudes increased, the percentage of errors on the Sternberg tests decreased. CONCLUSIONS: We suggest that by expanding the working memory capacity, larger units of information are retained in the system, enabling more effective error detection. The crucial functioning of the central-executive as a sub-component of the working memory is also discussed.

  15. Generalized Gaussian Error Calculus

    CERN Document Server

    Grabe, Michael

    2010-01-01

    For the first time in 200 years Generalized Gaussian Error Calculus addresses a rigorous, complete and self-consistent revision of the Gaussian error calculus. Since experimentalists realized that measurements in general are burdened by unknown systematic errors, the classical, widespread used evaluation procedures scrutinizing the consequences of random errors alone turned out to be obsolete. As a matter of course, the error calculus to-be, treating random and unknown systematic errors side by side, should ensure the consistency and traceability of physical units, physical constants and physical quantities at large. The generalized Gaussian error calculus considers unknown systematic errors to spawn biased estimators. Beyond, random errors are asked to conform to the idea of what the author calls well-defined measuring conditions. The approach features the properties of a building kit: any overall uncertainty turns out to be the sum of a contribution due to random errors, to be taken from a confidence inter...

  16. Medication errors: prescribing faults and prescription errors.

    Science.gov (United States)

    Velo, Giampaolo P; Minuz, Pietro

    2009-06-01

    1. Medication errors are common in general practice and in hospitals. Both errors in the act of writing (prescription errors) and prescribing faults due to erroneous medical decisions can result in harm to patients. 2. Any step in the prescribing process can generate errors. Slips, lapses, or mistakes are sources of errors, as in unintended omissions in the transcription of drugs. Faults in dose selection, omitted transcription, and poor handwriting are common. 3. Inadequate knowledge or competence and incomplete information about clinical characteristics and previous treatment of individual patients can result in prescribing faults, including the use of potentially inappropriate medications. 4. An unsafe working environment, complex or undefined procedures, and inadequate communication among health-care personnel, particularly between doctors and nurses, have been identified as important underlying factors that contribute to prescription errors and prescribing faults. 5. Active interventions aimed at reducing prescription errors and prescribing faults are strongly recommended. These should be focused on the education and training of prescribers and the use of on-line aids. The complexity of the prescribing procedure should be reduced by introducing automated systems or uniform prescribing charts, in order to avoid transcription and omission errors. Feedback control systems and immediate review of prescriptions, which can be performed with the assistance of a hospital pharmacist, are also helpful. Audits should be performed periodically.

  17. Effect of fatigue on landing performance assessed with the landing error scoring system (less) in patients after ACL reconstruction. A pilot study

    NARCIS (Netherlands)

    Gokeler, A; Eppinga, P; Dijkstra, P U; Welling, Wouter; Padua, D A; Otten, E.; Benjaminse, A

    BACKGROUND: Fatigue has been shown to affect performance of hop tests in patients after anterior cruciate ligament reconstruction (ACLR) compared to uninjured controls (CTRL). This may render the hop test less sensitive in detecting landing errors. The primary purpose of this study was to

  18. On-ward participation of a hospital pharmacist in a Dutch intensive care unit reduces prescribing errors and related patient harm: an intervention study

    NARCIS (Netherlands)

    Klopotowska, J.E.; Kuiper, R.; van Kan, H.J.; de Pont, A.C.; Dijkgraaf, M.G.; Lie-A-Huen, L.; Vroom, M.B.; Smorenburg, S.M.

    2010-01-01

    Introduction: Patients admitted to an intensive care unit (ICU) are at high risk for prescribing errors and related adverse drug events (ADEs). An effective intervention to decrease this risk, based on studies conducted mainly in North America, is on-ward participation of a clinical pharmacist in an

  19. On-ward participation of a hospital pharmacist in a Dutch intensive care unit reduces prescribing errors and related patient harm: an intervention study

    NARCIS (Netherlands)

    Klopotowska, Joanna E.; Kuiper, Rob; van Kan, Hendrikus J.; de Pont, Anne-Cornelie; Dijkgraaf, Marcel G.; Lie-A-Huen, Loraine; Vroom, Margreeth B.; Smorenburg, Susanne M.

    2010-01-01

    Patients admitted to an intensive care unit (ICU) are at high risk for prescribing errors and related adverse drug events (ADEs). An effective intervention to decrease this risk, based on studies conducted mainly in North America, is on-ward participation of a clinical pharmacist in an ICU team. As

  20. Correcting AUC for Measurement Error.

    Science.gov (United States)

    Rosner, Bernard; Tworoger, Shelley; Qiu, Weiliang

    2015-12-01

    Diagnostic biomarkers are used frequently in epidemiologic and clinical work. The ability of a diagnostic biomarker to discriminate between subjects who develop disease (cases) and subjects who do not (controls) is often measured by the area under the receiver operating characteristic curve (AUC). The diagnostic biomarkers are usually measured with error. Ignoring measurement error can cause biased estimation of AUC, which results in misleading interpretation of the efficacy of a diagnostic biomarker. Several methods have been proposed to correct AUC for measurement error, most of which required the normality assumption for the distributions of diagnostic biomarkers. In this article, we propose a new method to correct AUC for measurement error and derive approximate confidence limits for the corrected AUC. The proposed method does not require the normality assumption. Both real data analyses and simulation studies show good performance of the proposed measurement error correction method.

  1. Errors, error detection, error correction and hippocampal-region damage: data and theories.

    Science.gov (United States)

    MacKay, Donald G; Johnson, Laura W

    2013-11-01

    This review and perspective article outlines 15 observational constraints on theories of errors, error detection, and error correction, and their relation to hippocampal-region (HR) damage. The core observations come from 10 studies with H.M., an amnesic with cerebellar and HR damage but virtually no neocortical damage. Three studies examined the detection of errors planted in visual scenes (e.g., a bird flying in a fish bowl in a school classroom) and sentences (e.g., I helped themselves to the birthday cake). In all three experiments, H.M. detected reliably fewer errors than carefully matched memory-normal controls. Other studies examined the detection and correction of self-produced errors, with controls for comprehension of the instructions, impaired visual acuity, temporal factors, motoric slowing, forgetting, excessive memory load, lack of motivation, and deficits in visual scanning or attention. In these studies, H.M. corrected reliably fewer errors than memory-normal and cerebellar controls, and his uncorrected errors in speech, object naming, and reading aloud exhibited two consistent features: omission and anomaly. For example, in sentence production tasks, H.M. omitted one or more words in uncorrected encoding errors that rendered his sentences anomalous (incoherent, incomplete, or ungrammatical) reliably more often than controls. Besides explaining these core findings, the theoretical principles discussed here explain H.M.'s retrograde amnesia for once familiar episodic and semantic information; his anterograde amnesia for novel information; his deficits in visual cognition, sentence comprehension, sentence production, sentence reading, and object naming; and effects of aging on his ability to read isolated low frequency words aloud. These theoretical principles also explain a wide range of other data on error detection and correction and generate new predictions for future test. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Error Detection-Based Model to Assess Educational Outcomes in Crisis Resource Management Training: A Pilot Study.

    Science.gov (United States)

    Bouhabel, Sarah; Kay-Rivest, Emily; Nhan, Carol; Bank, Ilana; Nugus, Peter; Fisher, Rachel; Nguyen, Lily Hp

    2017-06-01

    Otolaryngology-head and neck surgery (OTL-HNS) residents face a variety of difficult, high-stress situations, which may occur early in their training. Since these events occur infrequently, simulation-based learning has become an important part of residents' training and is already well established in fields such as anesthesia and emergency medicine. In the domain of OTL-HNS, it is gradually gaining in popularity. Crisis Resource Management (CRM), a program adapted from the aviation industry, aims to improve outcomes of crisis situations by attempting to mitigate human errors. Some examples of CRM principles include cultivating situational awareness; promoting proper use of available resources; and improving rapid decision making, particularly in high-acuity, low-frequency clinical situations. Our pilot project sought to integrate CRM principles into an airway simulation course for OTL-HNS residents, but most important, it evaluated whether learning objectives were met, through use of a novel error identification model.

  3. Per-pixel bias-variance decomposition of continuous errors in data-driven geospatial modeling: A case study in environmental remote sensing

    Science.gov (United States)

    Gao, Jing; Burt, James E.

    2017-12-01

    This study investigates the usefulness of a per-pixel bias-variance error decomposition (BVD) for understanding and improving spatially-explicit data-driven models of continuous variables in environmental remote sensing (ERS). BVD is a model evaluation method originated from machine learning and have not been examined for ERS applications. Demonstrated with a showcase regression tree model mapping land imperviousness (0-100%) using Landsat images, our results showed that BVD can reveal sources of estimation errors, map how these sources vary across space, reveal the effects of various model characteristics on estimation accuracy, and enable in-depth comparison of different error metrics. Specifically, BVD bias maps can help analysts identify and delineate model spatial non-stationarity; BVD variance maps can indicate potential effects of ensemble methods (e.g. bagging), and inform efficient training sample allocation - training samples should capture the full complexity of the modeled process, and more samples should be allocated to regions with more complex underlying processes rather than regions covering larger areas. Through examining the relationships between model characteristics and their effects on estimation accuracy revealed by BVD for both absolute and squared errors (i.e. error is the absolute or the squared value of the difference between observation and estimate), we found that the two error metrics embody different diagnostic emphases, can lead to different conclusions about the same model, and may suggest different solutions for performance improvement. We emphasize BVD's strength in revealing the connection between model characteristics and estimation accuracy, as understanding this relationship empowers analysts to effectively steer performance through model adjustments.

  4. Preliminary study of the correlation between refractive error and corneal refractive power, corneal asphericity in myopic eye

    Directory of Open Access Journals (Sweden)

    Qi-Chao Han

    2014-05-01

    Full Text Available AIM: To investigate the correlation between myopic refractive error and relative factors, including the corneal refractive power, posterior refractive power, axial length, corneal asphericity coefficient Q value, central cornea thickness(CCTand intraocular pressure(IOP. METHODS:According to the degree of myopia measured by subjective refraction, 138 myopia patients were divided into three subgroups: mild group(-1.00D--3.00D, moderate group(-3.25D--6.00D, high group(>6.00D. The Pentacam anterior segment tomographer(Germany, Oculus Companywas used to measure the corneal refractive power, posterior refractive power, and corneal asphericity in the right eye. IOP, CCT and axial length were measured by a non-contact tonometer and A-scan ultrasonic, respectively. The data was analyzed with a Pearson correlation analysis and one-way ANOVA. RESULTS: The myopic refractive error was negatively correlated with the axial length(r=-0.682, Pr=0.009, P=0.925. The axial length was negatively correlated with corneal refractive power(r=-0.554, Pr=0.674, Pr=-0.375, P=0.01. There was no significantly correlation between the myopic refractive error and CCT, IOP(r=-0.138, P=0.141; r=-0.121, P=0.157. CONCLUSION:The corneal refractive power plays the role of emmetropization during the development of myopia. There is clinic significance for the correlation between Q value and refractive error, IOP to guide the corneal refractive surgery.

  5. Deadline pressure and human error: a study of human failures on a particle accelerator at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Tiagha, E.A.

    1982-01-01

    The decline in industrial efficiency may be linked to decreased reliability of complex automatic systems. This decline threatens the viability of complex organizations in industrialized economies. Industrial engineering techniques that minimize system failure by increasing the reliability of systems hardware are well developed in comparison with those available to reduce human operator errors. The problem of system reliability and the associated costs of breakdown can be reduced if we understand how highly skilled technical personnel function in complex operations and systems. The purpose of this research is to investigate how human errors are affected by deadline pressures, technical communication and other socio-dynamic factors. Through the analysis of a technologically complex particle accelerator prototype at Brookhaven National Laboratory, two failure mechanisms: (1) physical defects in the production process and (2) human operator errors were identified. Two instruments were used to collect information on human failures: objective laboratory data and a human failure questionnaire. The results of human failures from the objective data were used to test for the deadline hypothesis and also to validate the human failure questionnaire. To explain why the human failures occurred, data were collected from a four-part, closed choice questionnaire administered to two groups of scientists, engineers, and technicians, working together against a deadline to produce an engineering prototype of a particle accelerator

  6. Adjustment errors of sunstones in the first step of sky-polarimetric Viking navigation: studies with dichroic cordierite/ tourmaline and birefringent calcite crystals.

    Science.gov (United States)

    Száz, Dénes; Farkas, Alexandra; Blahó, Miklós; Barta, András; Egri, Ádám; Kretzer, Balázs; Hegedüs, Tibor; Jäger, Zoltán; Horváth, Gábor

    2016-01-01

    According to an old but still unproven theory, Viking navigators analysed the skylight polarization with dichroic cordierite or tourmaline, or birefringent calcite sunstones in cloudy/foggy weather. Combining these sunstones with their sun-dial, they could determine the position of the occluded sun, from which the geographical northern direction could be guessed. In psychophysical laboratory experiments, we studied the accuracy of the first step of this sky-polarimetric Viking navigation. We measured the adjustment error e of rotatable cordierite, tourmaline and calcite crystals when the task was to determine the direction of polarization of white light as a function of the degree of linear polarization p. From the obtained error functions e(p), the thresholds p* above which the first step can still function (i.e. when the intensity change seen through the rotating analyser can be sensed) were derived. Cordierite is about twice as reliable as tourmaline. Calcite sunstones have smaller adjustment errors if the navigator looks for that orientation of the crystal where the intensity difference between the two spots seen in the crystal is maximal, rather than minimal. For higher p (greater than p crit) of incident light, the adjustment errors of calcite are larger than those of the dichroic cordierite (p crit=20%) and tourmaline (p crit=45%), while for lower p (less than p crit) calcite usually has lower adjustment errors than dichroic sunstones. We showed that real calcite crystals are not as ideal sunstones as it was believed earlier, because they usually contain scratches, impurities and crystal defects which increase considerably their adjustment errors. Thus, cordierite and tourmaline can also be at least as good sunstones as calcite. Using the psychophysical e(p) functions and the patterns of the degree of skylight polarization measured by full-sky imaging polarimetry, we computed how accurately the northern direction can be determined with the use of the Viking

  7. Effect of the Absorbed Photosynthetically Active Radiation Estimation Error on Net Primary Production Estimation - A Study with MODIS FPAR and TOMS Ultraviolet Reflective Products

    International Nuclear Information System (INIS)

    Kobayashi, H.; Matsunaga, T.; Hoyano, A.

    2002-01-01

    Absorbed photosynthetically active radiation (APAR), which is defined as downward solar radiation in 400-700 nm absorbed by vegetation, is one of the significant variables for Net Primary Production (NPP) estimation from satellite data. Toward the reduction of the uncertainties in the global NPP estimation, it is necessary to clarify the APAR accuracy. In this paper, first we proposed the improved PAR estimation method based on Eck and Dye's method in which the ultraviolet (UV) reflectivity data derived from Total Ozone Mapping Spectrometer (TOMS) at the top of atmosphere were used for clouds transmittance estimation. The proposed method considered the variable effects of land surface UV reflectivity on the satellite-observed UV data. Monthly mean PAR comparisons between satellite-derived and ground-based data at various meteorological stations in Japan indicated that the improved PAR estimation method reduced the bias errors in the summer season. Assuming the relative error of the fraction of PAR (FPAR) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) to be 10%, we estimated APAR relative errors to be 10-15%. Annual NPP is calculated using APAR derived from MODIS/ FPAR and the improved PAR estimation method. It is shown that random and bias errors of annual NPP in a 1 km resolution pixel are less than 4% and 6% respectively. The APAR bias errors due to the PAR bias errors also affect the estimated total NPP. We estimated the most probable total annual NPP in Japan by subtracting the bias PAR errors. It amounts about 248 MtC/yr. Using the improved PAR estimation method, and Eck and Dye's method, total annual NPP is 4% and 9% difference from most probable value respectively. The previous intercomparison study among using fifteen NPP models4) showed that global NPP estimations among NPP models are 44.4-66.3 GtC/yr (coefficient of variation = 14%). Hence we conclude that the NPP estimation uncertainty due to APAR estimation error is small

  8. Systematic review of ERP and fMRI studies investigating inhibitory control and error processing in people with substance dependence and behavioural addictions

    Science.gov (United States)

    Luijten, Maartje; Machielsen, Marise W.J.; Veltman, Dick J.; Hester, Robert; de Haan, Lieuwe; Franken, Ingmar H.A.

    2014-01-01

    Background Several current theories emphasize the role of cognitive control in addiction. The present review evaluates neural deficits in the domains of inhibitory control and error processing in individuals with substance dependence and in those showing excessive addiction-like behaviours. The combined evaluation of event-related potential (ERP) and functional magnetic resonance imaging (fMRI) findings in the present review offers unique information on neural deficits in addicted individuals. Methods We selected 19 ERP and 22 fMRI studies using stop-signal, go/no-go or Flanker paradigms based on a search of PubMed and Embase. Results The most consistent findings in addicted individuals relative to healthy controls were lower N2, error-related negativity and error positivity amplitudes as well as hypoactivation in the anterior cingulate cortex (ACC), inferior frontal gyrus and dorsolateral prefrontal cortex. These neural deficits, however, were not always associated with impaired task performance. With regard to behavioural addictions, some evidence has been found for similar neural deficits; however, studies are scarce and results are not yet conclusive. Differences among the major classes of substances of abuse were identified and involve stronger neural responses to errors in individuals with alcohol dependence versus weaker neural responses to errors in other substance-dependent populations. Limitations Task design and analysis techniques vary across studies, thereby reducing comparability among studies and the potential of clinical use of these measures. Conclusion Current addiction theories were supported by identifying consistent abnormalities in prefrontal brain function in individuals with addiction. An integrative model is proposed, suggesting that neural deficits in the dorsal ACC may constitute a hallmark neurocognitive deficit underlying addictive behaviours, such as loss of control. PMID:24359877

  9. How Do Simulated Error Experiences Impact Attitudes Related to Error Prevention?

    Science.gov (United States)

    Breitkreuz, Karen R; Dougal, Renae L; Wright, Melanie C

    2016-10-01

    The objective of this project was to determine whether simulated exposure to error situations changes attitudes in a way that may have a positive impact on error prevention behaviors. Using a stratified quasi-randomized experiment design, we compared risk perception attitudes of a control group of nursing students who received standard error education (reviewed medication error content and watched movies about error experiences) to an experimental group of students who reviewed medication error content and participated in simulated error experiences. Dependent measures included perceived memorability of the educational experience, perceived frequency of errors, and perceived caution with respect to preventing errors. Experienced nursing students perceived the simulated error experiences to be more memorable than movies. Less experienced students perceived both simulated error experiences and movies to be highly memorable. After the intervention, compared with movie participants, simulation participants believed errors occurred more frequently. Both types of education increased the participants' intentions to be more cautious and reported caution remained higher than baseline for medication errors 6 months after the intervention. This study provides limited evidence of an advantage of simulation over watching movies describing actual errors with respect to manipulating attitudes related to error prevention. Both interventions resulted in long-term impacts on perceived caution in medication administration. Simulated error experiences made participants more aware of how easily errors can occur, and the movie education made participants more aware of the devastating consequences of errors.

  10. Clinical and Radiographic Evaluation of Procedural Errors during Preparation of Curved Root Canals with Hand and Rotary Instruments: A Randomized Clinical Study

    Science.gov (United States)

    Khanna, Rajesh; Handa, Aashish; Virk, Rupam Kaur; Ghai, Deepika; Handa, Rajni Sharma; Goel, Asim

    2017-01-01

    Background: The process of cleaning and shaping the canal is not an easy goal to obtain, as canal curvature played a significant role during the instrumentation of the curved canals. Aim: The present in vivo study was conducted to evaluate procedural errors during the preparation of curved root canals using hand Nitiflex and rotary K3XF instruments. Materials and Methods: Procedural errors such as ledge formation, instrument separation, and perforation (apical, furcal, strip) were determined in sixty patients, divided into two groups. In Group I, thirty teeth in thirty patients were prepared using hand Nitiflex system, and in Group II, thirty teeth in thirty patients were prepared using K3XF rotary system. The evaluation was done clinically as well as radiographically. The results recorded from both groups were compiled and put to statistical analysis. Statistical Analysis: Chi-square test was used to compare the procedural errors (instrument separation, ledge formation, and perforation). Results: In the present study, both hand Nitiflex and rotary K3XF showed ledge formation and instrument separation. Although ledge formation and instrument separation by rotary K3XF file system was less as compared to hand Nitiflex. No perforation was seen in both the instrument groups. Conclusion: Canal curvature played a significant role during the instrumentation of the curved canals. Procedural errors such as ledge formation and instrument separation by rotary K3XF file system were less as compared to hand Nitiflex. PMID:29042727

  11. Studying the errors in the estimation of the variation of energy by the "patched-conics" model in the three-dimensional swing-by

    Science.gov (United States)

    Negri, Rodolfo Batista; Prado, Antonio Fernando Bertachini de Almeida; Sukhanov, Alexander

    2017-11-01

    The swing-by maneuver is a technique used to change the energy of a spacecraft by using a close approach in a celestial body. This procedure was used many times in real missions. Usually, the first approach to design this type of mission is based on the "patched-conics" model, which splits the maneuver into three "two-body dynamics." This approach causes an error in the estimation of the energy variations, which depends on the geometry of the maneuver and the system of primaries considered. Therefore, the goal of the present paper is to study the errors caused by this approximation. The comparison of the results are made with the trajectories obtained using the more realistic restricted three-body problem, assumed here to be the "real values" for the maneuver. The results shown here describe the effects of each parameter involved in the swing-by. Some examples using bodies in the solar system are used in this part of the paper. The study is then generalized to cover different mass parameters, and its influence is analyzed to give an idea of the amount of the error expected for a given system of primaries. The results presented here may help in estimating errors in the preliminary mission analysis using the "patched-conics" approach.

  12. Field error lottery

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, C.J.; McVey, B. (Los Alamos National Lab., NM (USA)); Quimby, D.C. (Spectra Technology, Inc., Bellevue, WA (USA))

    1990-01-01

    The level of field errors in an FEL is an important determinant of its performance. We have computed 3D performance of a large laser subsystem subjected to field errors of various types. These calculations have been guided by simple models such as SWOOP. The technique of choice is utilization of the FELEX free electron laser code that now possesses extensive engineering capabilities. Modeling includes the ability to establish tolerances of various types: fast and slow scale field bowing, field error level, beam position monitor error level, gap errors, defocusing errors, energy slew, displacement and pointing errors. Many effects of these errors on relative gain and relative power extraction are displayed and are the essential elements of determining an error budget. The random errors also depend on the particular random number seed used in the calculation. The simultaneous display of the performance versus error level of cases with multiple seeds illustrates the variations attributable to stochasticity of this model. All these errors are evaluated numerically for comprehensive engineering of the system. In particular, gap errors are found to place requirements beyond mechanical tolerances of {plus minus}25{mu}m, and amelioration of these may occur by a procedure utilizing direct measurement of the magnetic fields at assembly time. 4 refs., 12 figs.

  13. Comparison of error-based and errorless learning for people with severe traumatic brain injury: study protocol for a randomized control trial.

    Science.gov (United States)

    Ownsworth, Tamara; Fleming, Jennifer; Tate, Robyn; Shum, David H K; Griffin, Janelle; Schmidt, Julia; Lane-Brown, Amanda; Kendall, Melissa; Chevignard, Mathilde

    2013-11-05

    Poor skills generalization poses a major barrier to successful outcomes of rehabilitation after traumatic brain injury (TBI). Error-based learning (EBL) is a relatively new intervention approach that aims to promote skills generalization by teaching people internal self-regulation skills, or how to anticipate, monitor and correct their own errors. This paper describes the protocol of a study that aims to compare the efficacy of EBL and errorless learning (ELL) for improving error self-regulation, behavioral competency, awareness of deficits and long-term outcomes after TBI. This randomized, controlled trial (RCT) has two arms (EBL and ELL); each arm entails 8 × 2 h training sessions conducted within the participants' homes. The first four sessions involve a meal preparation activity, and the final four sessions incorporate a multitasking errand activity. Based on a sample size estimate, 135 participants with severe TBI will be randomized into either the EBL or ELL condition. The primary outcome measure assesses error self-regulation skills on a task related to but distinct from training. Secondary outcomes include measures of self-monitoring and self-regulation, behavioral competency, awareness of deficits, role participation and supportive care needs. Assessments will be conducted at pre-intervention, post-intervention, and at 6-months post-intervention. This study seeks to determine the efficacy and long-term impact of EBL for training internal self-regulation strategies following severe TBI. In doing so, the study will advance theoretical understanding of the role of errors in task learning and skills generalization. EBL has the potential to reduce the length and costs of rehabilitation and lifestyle support because the techniques could enhance generalization success and lifelong application of strategies after TBI. ACTRN12613000585729.

  14. Prescription Errors in Psychiatry

    African Journals Online (AJOL)

    Arun Kumar Agnihotri

    clinical pharmacists in detecting errors before they have a (sometimes serious) clinical impact should not be underestimated. Research on medication error in mental health care is limited. .... participation in ward rounds and adverse drug.

  15. [Study on the Effects and Compensation Effect of Recording Parameters Error on Imaging Performance of Holographic Grating in On-Line Spectral Diagnose].

    Science.gov (United States)

    Jiang, Yan-xiu; Bayanheshig; Yang, Shuo; Zhao, Xu-long; Wu, Na; Li, Wen-hao

    2016-03-01

    To making the high resolution grating, a numerical calculation was used to analyze the effect of recording parameters on groove density, focal curve and imaging performance of the grating and their compensation. Based on Fermat' s principle, light path function and aberration, the effect on imaging performance of the grating was analyzed. In the case of fixed using parameters, the error of the recording angle has a greater influence on imaging performance, therefore the gain of the weight of recording angle can improve the accuracy of the recording angle values in the optimization; recording distance has little influence on imaging performance; the relative errors of recording parameters cause the change of imaging performance of the grating; the results indicate that recording parameter errors can be compensated by adjusting its corresponding parameter. The study can give theoretical guidance to the fabrication for high resolution varied-line-space plane holographic grating in on-line spectral diagnostic and reduce the alignment difficulty by analyze the main error effect the imaging performance and propose the compensation method.

  16. A GENERAL STUDY OF THE INFLUENCE OF CATASTROPHIC PHOTOMETRIC REDSHIFT ERRORS ON COSMOLOGY WITH COSMIC SHEAR TOMOGRAPHY

    International Nuclear Information System (INIS)

    Hearin, Andrew P.; Zentner, Andrew R.; Ma Zhaoming; Huterer, Dragan

    2010-01-01

    A goal of forthcoming imaging surveys is to use weak gravitational lensing shear measurements to constrain dark energy. A challenge to this program is that redshifts to the lensed, source galaxies must be determined using photometric, rather than spectroscopic, information. We quantify the importance of uncalibrated photometric redshift outliers to the dark energy goals of forthcoming imaging surveys in a manner that does not assume any particular photometric redshift technique or template. In so doing, we provide an approximate blueprint for computing the influence of specific outlier populations on dark energy constraints. We find that outlier populations whose photo-z distributions are tightly localized about a significantly biased redshift must be controlled to a per-galaxy rate of (1-3) x 10 -3 to insure that systematic errors on dark energy parameters are rendered negligible. In the complementary limit, a subset of imaged galaxies with uncalibrated photometric redshifts distributed over a broad range must be limited to fewer than a per-galaxy error rate of F cat ∼ -4 . Additionally, we explore the relative importance of calibrating the photo-z's of a core set of relatively well-understood galaxies as compared to the need to identify potential catastrophic photo-z outliers. We discuss the degradation of the statistical constraints on dark energy parameters induced by excising source galaxies at high- and low-photometric redshifts, concluding that removing galaxies with photometric redshifts z ph ∼> 2.4 and z ph ∼< 0.3 may mitigate damaging catastrophic redshift outliers at a relatively small (∼<20%) cost in statistical error. In an Appendix, we show that forecasts for the degradation in dark energy parameter constraints due to uncertain photometric redshifts depend sensitively on the treatment of the nonlinear matter power spectrum. In particular, previous work using Peacock and Dodds may have overestimated the photo-z calibration requirements of

  17. Human errors in NPP operations

    International Nuclear Information System (INIS)

    Sheng Jufang

    1993-01-01

    Based on the operational experiences of nuclear power plants (NPPs), the importance of studying human performance problems is described. Statistical analysis on the significance or frequency of various root-causes and error-modes from a large number of human-error-related events demonstrate that the defects in operation/maintenance procedures, working place factors, communication and training practices are primary root-causes, while omission, transposition, quantitative mistake are the most frequent among the error-modes. Recommendations about domestic research on human performance problem in NPPs are suggested

  18. Valuing Errors for Learning: Espouse or Enact?

    Science.gov (United States)

    Grohnert, Therese; Meuwissen, Roger H. G.; Gijselaers, Wim H.

    2017-01-01

    Purpose: This study aims to investigate how organisations can discourage covering up and instead encourage learning from errors through a supportive learning from error climate. In explaining professionals' learning from error behaviour, this study distinguishes between espoused (verbally expressed) and enacted (behaviourally expressed) values…

  19. Endoscopic localization of colorectal cancer: Study of its accuracy and possible error factors Localización endoscópica del cáncer colorrectal: estudio de su precisión y posibles factores de error

    Directory of Open Access Journals (Sweden)

    Fernando Borda

    2012-11-01

    Full Text Available Introduction: accurate preoperative localization of colorectal cancer (CRC is very important, with a wide range of published error rates. Aim: to determine accuracy of endoscopic localization of CRC in comparison with preoperative computed tomography (CT. To analyse variables that could be associated with a wrong endoscopic localization. Patients and methods: endoscopic and CT localization of a series of CRC without previous surgery were reviewed. We studied the concordance between endoscopic and radiologic localization against operative findings comparing accuracy of endoscopy and CT. We analysed the frequency of wrong endoscopic diagnoses with regard to a series of patient, endoscopy and tumor variables. Results: two hundred thirty seven CRC in 223 patients were studied. Concordance with surgical localization was: colonoscopy = 0.87 and CT = 0.69. Endoscopic localization accuracy was: 91.1%; CT: 76.2%: p = 0.00001; OR = 3.22 (1.82-5.72. Obstructive cancer presented a higher rate of wrong localization: 18 vs. 5.7% in non-obstructive tumors (p = 0.0034; OR = 3.65 (1.35-9.96. Endoscopic localization mistakes varied depending on tumor location, being more frequent in descending colon: 36.3%, p = 0.014; OR = 6.23 (1.38-26.87 and cecum: 23.1%, p = 0.007; OR = 3.92 (1.20-12.43. Conclusions: endoscopic accuracy for CRC localization was very high and significantly better than CT accuracy. Obstructive tumor and those located in the descending colon or cecum were associated with a significant increase of the error risk of CRC endoscopic localization.Introducción: una correcta localización preoperatoria del cáncer colorrectal (CCR es muy importante, siendo variables las tasas de error de localización endoscópica publicadas. Objetivo: determinar la precisión de la localización endoscópica del CCR, comparándola con la del TAC preoperatorio. Analizar las variables que pudieran asociarse a una localización endoscópica errónea. Pacientes y m

  20. Effects of registration error on parametric response map analysis: a simulation study using liver CT-perfusion images

    International Nuclear Information System (INIS)

    Lausch, A; Lee, T Y; Wong, E; Jensen, N K G; Chen, J; Lock, M

    2014-01-01

    Purpose: To investigate the effects of registration error (RE) on parametric response map (PRM) analysis of pre and post-radiotherapy (RT) functional images. Methods: Arterial blood flow maps (ABF) were generated from the CT-perfusion scans of 5 patients with hepatocellular carcinoma. ABF values within each patient map were modified to produce seven new ABF maps simulating 7 distinct post-RT functional change scenarios. Ground truth PRMs were generated for each patient by comparing the simulated and original ABF maps. Each simulated ABF map was then deformed by different magnitudes of realistic respiratory motion in order to simulate RE. PRMs were generated for each of the deformed maps and then compared to the ground truth PRMs to produce estimates of RE-induced misclassification. Main findings: The percentage of voxels misclassified as decreasing, no change, and increasing, increased with RE For all patients, increasing RE was observed to increase the number of high post-RT ABF voxels associated with low pre-RT ABF voxels and vice versa. 3 mm of average tumour RE resulted in 18-45% tumour voxel misclassification rates. Conclusions: RE induced misclassification posed challenges for PRM analysis in the liver where registration accuracy tends to be lower. Quantitative understanding of the sensitivity of the PRM method to registration error is required if PRMs are to be used to guide radiation therapy dose painting techniques.

  1. Markov chain beam randomization: a study of the impact of PLANCK beam measurement errors on cosmological parameter estimation

    Science.gov (United States)

    Rocha, G.; Pagano, L.; Górski, K. M.; Huffenberger, K. M.; Lawrence, C. R.; Lange, A. E.

    2010-04-01

    We introduce a new method to propagate uncertainties in the beam shapes used to measure the cosmic microwave background to cosmological parameters determined from those measurements. The method, called markov chain beam randomization (MCBR), randomly samples from a set of templates or functions that describe the beam uncertainties. The method is much faster than direct numerical integration over systematic “nuisance” parameters, and is not restricted to simple, idealized cases as is analytic marginalization. It does not assume the data are normally distributed, and does not require Gaussian priors on the specific systematic uncertainties. We show that MCBR properly accounts for and provides the marginalized errors of the parameters. The method can be generalized and used to propagate any systematic uncertainties for which a set of templates is available. We apply the method to the Planck satellite, and consider future experiments. Beam measurement errors should have a small effect on cosmological parameters as long as the beam fitting is performed after removal of 1/f noise.

  2. Quantile Regression With Measurement Error

    KAUST Repository

    Wei, Ying

    2009-08-27

    Regression quantiles can be substantially biased when the covariates are measured with error. In this paper we propose a new method that produces consistent linear quantile estimation in the presence of covariate measurement error. The method corrects the measurement error induced bias by constructing joint estimating equations that simultaneously hold for all the quantile levels. An iterative EM-type estimation algorithm to obtain the solutions to such joint estimation equations is provided. The finite sample performance of the proposed method is investigated in a simulation study, and compared to the standard regression calibration approach. Finally, we apply our methodology to part of the National Collaborative Perinatal Project growth data, a longitudinal study with an unusual measurement error structure. © 2009 American Statistical Association.

  3. An Error Analysis on TFL Learners’ Writings

    Directory of Open Access Journals (Sweden)

    Arif ÇERÇİ

    2016-12-01

    Full Text Available The main purpose of the present study is to identify and represent TFL learners’ writing errors through error analysis. All the learners started learning Turkish as foreign language with A1 (beginner level and completed the process by taking C1 (advanced certificate in TÖMER at Gaziantep University. The data of the present study were collected from 14 students’ writings in proficiency exams for each level. The data were grouped as grammatical, syntactic, spelling, punctuation, and word choice errors. The ratio and categorical distributions of identified errors were analyzed through error analysis. The data were analyzed through statistical procedures in an effort to determine whether error types differ according to the levels of the students. The errors in this study are limited to the linguistic and intralingual developmental errors

  4. Errors in otology.

    Science.gov (United States)

    Kartush, J M

    1996-11-01

    Practicing medicine successfully requires that errors in diagnosis and treatment be minimized. Malpractice laws encourage litigators to ascribe all medical errors to incompetence and negligence. There are, however, many other causes of unintended outcomes. This article describes common causes of errors and suggests ways to minimize mistakes in otologic practice. Widespread dissemination of knowledge about common errors and their precursors can reduce the incidence of their occurrence. Consequently, laws should be passed to allow for a system of non-punitive, confidential reporting of errors and "near misses" that can be shared by physicians nationwide.

  5. AN ANALYSIS OF GRAMMATICAL ERRORS IN SPEECH AT THE STUDENTS OF ENGLISH EDUCATION STUDY PROGRAM OF MUHAMMADIYAH UNIVERSITY OF METRO ACADEMIC YEAR 2013/2014

    Directory of Open Access Journals (Sweden)

    Septian Dwi Sondiana

    2017-02-01

    Full Text Available The objectives of the research are to find out the types of grammatical errors in English students’ speech; to find out the percentage of grammatical errors in English students’ speech; to find out the factors influencing English students’ grammatical errors in their speech. Based on the data, the students have problem in producing verb group, errors in subject-verb agreement, errors in the use of articles, errors in the use of prepositions, errors in noun pluralization, errors in the use of pronouns, and errors in the use of conjunctions. It shows that Anisa made eleven sentences in 2 minutes 28 seconds. She made eight errors. Dewi made seven sentences in 1 minutes 57 seconds. She made five errors. Fatika made sixteen sentences in 4 minutes 14 seconds. She made eight errors. Fitri made sixteen sentences in 4 minutes 23 seconds. She made seven errors. Ibnu  made  ten sentences in 2 minutes 18 seconds. He made eight errors. Linda made fiveteen sentences in 3 minutes 7 seconds. She made eight errors. Musli made fourteen sentences in 2 minutes 39 seconds. She made six errors. Nyoman made twelve sentences in 3 minutes 43 seconds. He made nine errors. Pera made ten sentences in 2 minutes 23 seconds. She made seven errors. Sri made fourteen sentences in 6 minutes 34 seconds. She made eleven errors. And about the percentages of errors, here is the data; Anisa: 72,73% of errors; Dewi: 71,4% of errors; Fatika: 50% of errors; Fitri: 43,75% of errors; Ibnu: 80% of errors; Linda: 53,3% of errors; Musli: 42,8% of errors; Nyoman: 75% of errors; Pera: 70% of errors; Sri: 78,57% of errors. Based on interview, it shows it can be concluded the factors influence of English students’ grammatical errors in their speech when their speak using grammar rule. The internal factors are; The first, the students are still difficult to make feeling, for example; confident, feel scary, when they are speaking in public. The second, the students are not mastered in

  6. An adaptive orienting theory of error processing.

    Science.gov (United States)

    Wessel, Jan R

    2018-03-01

    The ability to detect and correct action errors is paramount to safe and efficient goal-directed behaviors. Existing work on the neural underpinnings of error processing and post-error behavioral adaptations has led to the development of several mechanistic theories of error processing. These theories can be roughly grouped into adaptive and maladaptive theories. While adaptive theories propose that errors trigger a cascade of processes that will result in improved behavior after error commission, maladaptive theories hold that error commission momentarily impairs behavior. Neither group of theories can account for all available data, as different empirical studies find both impaired and improved post-error behavior. This article attempts a synthesis between the predictions made by prominent adaptive and maladaptive theories. Specifically, it is proposed that errors invoke a nonspecific cascade of processing that will rapidly interrupt and inhibit ongoing behavior and cognition, as well as orient attention toward the source of the error. It is proposed that this cascade follows all unexpected action outcomes, not just errors. In the case of errors, this cascade is followed by error-specific, controlled processing, which is specifically aimed at (re)tuning the existing task set. This theory combines existing predictions from maladaptive orienting and bottleneck theories with specific neural mechanisms from the wider field of cognitive control, including from error-specific theories of adaptive post-error processing. The article aims to describe the proposed framework and its implications for post-error slowing and post-error accuracy, propose mechanistic neural circuitry for post-error processing, and derive specific hypotheses for future empirical investigations. © 2017 Society for Psychophysiological Research.

  7. [Medical errors: inevitable but preventable].

    Science.gov (United States)

    Giard, R W

    2001-10-27

    Medical errors are increasingly reported in the lay press. Studies have shown dramatic error rates of 10 percent or even higher. From a methodological point of view, studying the frequency and causes of medical errors is far from simple. Clinical decisions on diagnostic or therapeutic interventions are always taken within a clinical context. Reviewing outcomes of interventions without taking into account both the intentions and the arguments for a particular action will limit the conclusions from a study on the rate and preventability of errors. The interpretation of the preventability of medical errors is fraught with difficulties and probably highly subjective. Blaming the doctor personally does not do justice to the actual situation and especially the organisational framework. Attention for and improvement of the organisational aspects of error are far more important then litigating the person. To err is and will remain human and if we want to reduce the incidence of faults we must be able to learn from our mistakes. That requires an open attitude towards medical mistakes, a continuous effort in their detection, a sound analysis and, where feasible, the institution of preventive measures.

  8. Random and systematic errors in case–control studies calculating the injury risk of driving under the influence of psychoactive substances

    DEFF Research Database (Denmark)

    Houwing, Sjoerd; Hagenzieker, Marjan; Mathijssen, René P.M.

    2013-01-01

    Between 2006 and 2010, six population based case-control studies were conducted as part of the European research-project DRUID (DRiving Under the Influence of Drugs, alcohol and medicines). The aim of these case-control studies was to calculate odds ratios indicating the relative risk of serious....... The list of indicators that was identified in this study is useful both as guidance for systematic reviews and meta-analyses and for future epidemiological studies in the field of driving under the influence to minimize sources of errors already at the start of the study. © 2013 Published by Elsevier Ltd....

  9. Error field considerations for BPX

    International Nuclear Information System (INIS)

    LaHaye, R.J.

    1992-01-01

    Irregularities in the position of poloidal and/or toroidal field coils in tokamaks produce resonant toroidal asymmetries in the vacuum magnetic fields. Otherwise stable tokamak discharges become non-linearly unstable to disruptive locked modes when subjected to low level error fields. Because of the field errors, magnetic islands are produced which would not otherwise occur in tearing mode table configurations; a concomitant reduction of the total confinement can result. Poloidal and toroidal asymmetries arise in the heat flux to the divertor target. In this paper, the field errors from perturbed BPX coils are used in a field line tracing code of the BPX equilibrium to study these deleterious effects. Limits on coil irregularities for device design and fabrication are computed along with possible correcting coils for reducing such field errors

  10. Numerical optimization with computational errors

    CERN Document Server

    Zaslavski, Alexander J

    2016-01-01

    This book studies the approximate solutions of optimization problems in the presence of computational errors. A number of results are presented on the convergence behavior of algorithms in a Hilbert space; these algorithms are examined taking into account computational errors. The author illustrates that algorithms generate a good approximate solution, if computational errors are bounded from above by a small positive constant. Known computational errors are examined with the aim of determining an approximate solution. Researchers and students interested in the optimization theory and its applications will find this book instructive and informative. This monograph contains 16 chapters; including a chapters devoted to the subgradient projection algorithm, the mirror descent algorithm, gradient projection algorithm, the Weiszfelds method, constrained convex minimization problems, the convergence of a proximal point method in a Hilbert space, the continuous subgradient method, penalty methods and Newton’s meth...

  11. Dual processing and diagnostic errors.

    Science.gov (United States)

    Norman, Geoff

    2009-09-01

    In this paper, I review evidence from two theories in psychology relevant to diagnosis and diagnostic errors. "Dual Process" theories of thinking, frequently mentioned with respect to diagnostic error, propose that categorization decisions can be made with either a fast, unconscious, contextual process called System 1 or a slow, analytical, conscious, and conceptual process, called System 2. Exemplar theories of categorization propose that many category decisions in everyday life are made by unconscious matching to a particular example in memory, and these remain available and retrievable individually. I then review studies of clinical reasoning based on these theories, and show that the two processes are equally effective; System 1, despite its reliance in idiosyncratic, individual experience, is no more prone to cognitive bias or diagnostic error than System 2. Further, I review evidence that instructions directed at encouraging the clinician to explicitly use both strategies can lead to consistent reduction in error rates.

  12. Acoustic Evidence for Phonologically Mismatched Speech Errors

    Science.gov (United States)

    Gormley, Andrea

    2015-01-01

    Speech errors are generally said to accommodate to their new phonological context. This accommodation has been validated by several transcription studies. The transcription methodology is not the best choice for detecting errors at this level, however, as this type of error can be difficult to perceive. This paper presents an acoustic analysis of…

  13. Average beta-beating from random errors

    CERN Document Server

    Tomas Garcia, Rogelio; Langner, Andy Sven; Malina, Lukas; Franchi, Andrea; CERN. Geneva. ATS Department

    2018-01-01

    The impact of random errors on average β-beating is studied via analytical derivations and simulations. A systematic positive β-beating is expected from random errors quadratic with the sources or, equivalently, with the rms β-beating. However, random errors do not have a systematic effect on the tune.

  14. Naming game with learning errors in communications

    OpenAIRE

    Lou, Yang; Chen, Guanrong

    2014-01-01

    Naming game simulates the process of naming an objective by a population of agents organized in a certain communication network topology. By pair-wise iterative interactions, the population reaches a consensus state asymptotically. In this paper, we study naming game with communication errors during pair-wise conversations, where errors are represented by error rates in a uniform probability distribution. First, a model of naming game with learning errors in communications (NGLE) is proposed....

  15. Visual disability, visual function, and myopia among rural chinese secondary school children: the Xichang Pediatric Refractive Error Study (X-PRES)--report 1.

    Science.gov (United States)

    Congdon, Nathan; Wang, Yunfei; Song, Yue; Choi, Kai; Zhang, Mingzhi; Zhou, Zhongxia; Xie, Zhenling; Li, Liping; Liu, Xueyu; Sharma, Abhishek; Wu, Bin; Lam, Dennis S C

    2008-07-01

    To evaluate visual acuity, visual function, and prevalence of refractive error among Chinese secondary-school children in a cross-sectional school-based study. Uncorrected, presenting, and best corrected visual acuity, cycloplegic autorefraction with refinement, and self-reported visual function were assessed in a random, cluster sample of rural secondary school students in Xichang, China. Among the 1892 subjects (97.3% of the consenting children, 84.7% of the total sample), mean age was 14.7 +/- 0.8 years, 51.2% were female, and 26.4% were wearing glasses. The proportion of children with uncorrected, presenting, and corrected visual disability (visual disability when tested without correction, 98.7% was due to refractive error, while only 53.8% (414/770) of these children had appropriate correction. The girls had significantly (P visual disability and myopia visual function (ANOVA trend test, P Visual disability in this population was common, highly correctable, and frequently uncorrected. The impact of refractive error on self-reported visual function was significant. Strategies and studies to understand and remove barriers to spectacle wear are needed.

  16. The error in total error reduction.

    Science.gov (United States)

    Witnauer, James E; Urcelay, Gonzalo P; Miller, Ralph R

    2014-02-01

    Most models of human and animal learning assume that learning is proportional to the discrepancy between a delivered outcome and the outcome predicted by all cues present during that trial (i.e., total error across a stimulus compound). This total error reduction (TER) view has been implemented in connectionist and artificial neural network models to describe the conditions under which weights between units change. Electrophysiological work has revealed that the activity of dopamine neurons is correlated with the total error signal in models of reward learning. Similar neural mechanisms presumably support fear conditioning, human contingency learning, and other types of learning. Using a computational modeling approach, we compared several TER models of associative learning to an alternative model that rejects the TER assumption in favor of local error reduction (LER), which assumes that learning about each cue is proportional to the discrepancy between the delivered outcome and the outcome predicted by that specific cue on that trial. The LER model provided a better fit to the reviewed data than the TER models. Given the superiority of the LER model with the present data sets, acceptance of TER should be tempered. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Estimation of error in maximal intensity projection-based internal target volume of lung tumors: a simulation and comparison study using dynamic magnetic resonance imaging.

    Science.gov (United States)

    Cai, Jing; Read, Paul W; Baisden, Joseph M; Larner, James M; Benedict, Stanley H; Sheng, Ke

    2007-11-01

    To evaluate the error in four-dimensional computed tomography (4D-CT) maximal intensity projection (MIP)-based lung tumor internal target volume determination using a simulation method based on dynamic magnetic resonance imaging (dMRI). Eight healthy volunteers and six lung tumor patients underwent a 5-min MRI scan in the sagittal plane to acquire dynamic images of lung motion. A MATLAB program was written to generate re-sorted dMRI using 4D-CT acquisition methods (RedCAM) by segmenting and rebinning the MRI scans. The maximal intensity projection images were generated from RedCAM and dMRI, and the errors in the MIP-based internal target area (ITA) from RedCAM (epsilon), compared with those from dMRI, were determined and correlated with the subjects' respiratory variability (nu). Maximal intensity projection-based ITAs from RedCAM were comparatively smaller than those from dMRI in both phantom studies (epsilon = -21.64% +/- 8.23%) and lung tumor patient studies (epsilon = -20.31% +/- 11.36%). The errors in MIP-based ITA from RedCAM correlated linearly (epsilon = -5.13nu - 6.71, r(2) = 0.76) with the subjects' respiratory variability. Because of the low temporal resolution and retrospective re-sorting, 4D-CT might not accurately depict the excursion of a moving tumor. Using a 4D-CT MIP image to define the internal target volume might therefore cause underdosing and an increased risk of subsequent treatment failure. Patient-specific respiratory variability might also be a useful predictor of the 4D-CT-induced error in MIP-based internal target volume determination.

  18. Moderation of the Relationship Between Reward Expectancy and Prediction Error-Related Ventral Striatal Reactivity by Anhedonia in Unmedicated Major Depressive Disorder: Findings From the EMBARC Study

    Science.gov (United States)

    Greenberg, Tsafrir; Chase, Henry W.; Almeida, Jorge R.; Stiffler, Richelle; Zevallos, Carlos R.; Aslam, Haris A.; Deckersbach, Thilo; Weyandt, Sarah; Cooper, Crystal; Toups, Marisa; Carmody, Thomas; Kurian, Benji; Peltier, Scott; Adams, Phillip; McInnis, Melvin G.; Oquendo, Maria A.; McGrath, Patrick J.; Fava, Maurizio; Weissman, Myrna; Parsey, Ramin; Trivedi, Madhukar H.; Phillips, Mary L.

    2016-01-01

    Objective Anhedonia, disrupted reward processing, is a core symptom of major depressive disorder. Recent findings demonstrate altered reward-related ventral striatal reactivity in depressed individuals, but the extent to which this is specific to anhedonia remains poorly understood. The authors examined the effect of anhedonia on reward expectancy (expected outcome value) and prediction error-(discrepancy between expected and actual outcome) related ventral striatal reactivity, as well as the relationship between these measures. Method A total of 148 unmedicated individuals with major depressive disorder and 31 healthy comparison individuals recruited for the multisite EMBARC (Establishing Moderators and Biosignatures of Antidepressant Response in Clinical Care) study underwent functional MRI during a well-validated reward task. Region of interest and whole-brain data were examined in the first- (N=78) and second- (N=70) recruited cohorts, as well as the total sample, of depressed individuals, and in healthy individuals. Results Healthy, but not depressed, individuals showed a significant inverse relationship between reward expectancy and prediction error-related right ventral striatal reactivity. Across all participants, and in depressed individuals only, greater anhedonia severity was associated with a reduced reward expectancy-prediction error inverse relationship, even after controlling for other symptoms. Conclusions The normal reward expectancy and prediction error-related ventral striatal reactivity inverse relationship concords with conditioning models, predicting a shift in ventral striatal responding from reward outcomes to reward cues. This study shows, for the first time, an absence of this relationship in two cohorts of unmedicated depressed individuals and a moderation of this relationship by anhedonia, suggesting reduced reward-contingency learning with greater anhedonia. These findings help elucidate neural mechanisms of anhedonia, as a step toward

  19. Moderation of the Relationship Between Reward Expectancy and Prediction Error-Related Ventral Striatal Reactivity by Anhedonia in Unmedicated Major Depressive Disorder: Findings From the EMBARC Study.

    Science.gov (United States)

    Greenberg, Tsafrir; Chase, Henry W; Almeida, Jorge R; Stiffler, Richelle; Zevallos, Carlos R; Aslam, Haris A; Deckersbach, Thilo; Weyandt, Sarah; Cooper, Crystal; Toups, Marisa; Carmody, Thomas; Kurian, Benji; Peltier, Scott; Adams, Phillip; McInnis, Melvin G; Oquendo, Maria A; McGrath, Patrick J; Fava, Maurizio; Weissman, Myrna; Parsey, Ramin; Trivedi, Madhukar H; Phillips, Mary L

    2015-09-01

    Anhedonia, disrupted reward processing, is a core symptom of major depressive disorder. Recent findings demonstrate altered reward-related ventral striatal reactivity in depressed individuals, but the extent to which this is specific to anhedonia remains poorly understood. The authors examined the effect of anhedonia on reward expectancy (expected outcome value) and prediction error- (discrepancy between expected and actual outcome) related ventral striatal reactivity, as well as the relationship between these measures. A total of 148 unmedicated individuals with major depressive disorder and 31 healthy comparison individuals recruited for the multisite EMBARC (Establishing Moderators and Biosignatures of Antidepressant Response in Clinical Care) study underwent functional MRI during a well-validated reward task. Region of interest and whole-brain data were examined in the first- (N=78) and second- (N=70) recruited cohorts, as well as the total sample, of depressed individuals, and in healthy individuals. Healthy, but not depressed, individuals showed a significant inverse relationship between reward expectancy and prediction error-related right ventral striatal reactivity. Across all participants, and in depressed individuals only, greater anhedonia severity was associated with a reduced reward expectancy-prediction error inverse relationship, even after controlling for other symptoms. The normal reward expectancy and prediction error-related ventral striatal reactivity inverse relationship concords with conditioning models, predicting a shift in ventral striatal responding from reward outcomes to reward cues. This study shows, for the first time, an absence of this relationship in two cohorts of unmedicated depressed individuals and a moderation of this relationship by anhedonia, suggesting reduced reward-contingency learning with greater anhedonia. These findings help elucidate neural mechanisms of anhedonia, as a step toward identifying potential biosignatures

  20. Statistical methods and errors in family medicine articles between 2010 and 2014-Suez Canal University, Egypt: A cross-sectional study.

    Science.gov (United States)

    Nour-Eldein, Hebatallah

    2016-01-01

    With limited statistical knowledge of most physicians it is not uncommon to find statistical errors in research articles. To determine the statistical methods and to assess the statistical errors in family medicine (FM) research articles that were published between 2010 and 2014. This was a cross-sectional study. All 66 FM research articles that were published over 5 years by FM authors with affiliation to Suez Canal University were screened by the researcher between May and August 2015. Types and frequencies of statistical methods were reviewed in all 66 FM articles. All 60 articles with identified inferential statistics were examined for statistical errors and deficiencies. A comprehensive 58-item checklist based on statistical guidelines was used to evaluate the statistical quality of FM articles. Inferential methods were recorded in 62/66 (93.9%) of FM articles. Advanced analyses were used in 29/66 (43.9%). Contingency tables 38/66 (57.6%), regression (logistic, linear) 26/66 (39.4%), and t-test 17/66 (25.8%) were the most commonly used inferential tests. Within 60 FM articles with identified inferential statistics, no prior sample size 19/60 (31.7%), application of wrong statistical tests 17/60 (28.3%), incomplete documentation of statistics 59/60 (98.3%), reporting P value without test statistics 32/60 (53.3%), no reporting confidence interval with effect size measures 12/60 (20.0%), use of mean (standard deviation) to describe ordinal/nonnormal data 8/60 (13.3%), and errors related to interpretation were mainly for conclusions without support by the study data 5/60 (8.3%). Inferential statistics were used in the majority of FM articles. Data analysis and reporting statistics are areas for improvement in FM research articles.

  1. Errors in Neonatology

    OpenAIRE

    Antonio Boldrini; Rosa T. Scaramuzzo; Armando Cuttano

    2013-01-01

    Introduction: Danger and errors are inherent in human activities. In medical practice errors can lean to adverse events for patients. Mass media echo the whole scenario. Methods: We reviewed recent published papers in PubMed database to focus on the evidence and management of errors in medical practice in general and in Neonatology in particular. We compared the results of the literature with our specific experience in Nina Simulation Centre (Pisa, Italy). Results: In Neonatology the main err...

  2. Eliminating US hospital medical errors.

    Science.gov (United States)

    Kumar, Sameer; Steinebach, Marc

    2008-01-01

    Healthcare costs in the USA have continued to rise steadily since the 1980s. Medical errors are one of the major causes of deaths and injuries of thousands of patients every year, contributing to soaring healthcare costs. The purpose of this study is to examine what has been done to deal with the medical-error problem in the last two decades and present a closed-loop mistake-proof operation system for surgery processes that would likely eliminate preventable medical errors. The design method used is a combination of creating a service blueprint, implementing the six sigma DMAIC cycle, developing cause-and-effect diagrams as well as devising poka-yokes in order to develop a robust surgery operation process for a typical US hospital. In the improve phase of the six sigma DMAIC cycle, a number of poka-yoke techniques are introduced to prevent typical medical errors (identified through cause-and-effect diagrams) that may occur in surgery operation processes in US hospitals. It is the authors' assertion that implementing the new service blueprint along with the poka-yokes, will likely result in the current medical error rate to significantly improve to the six-sigma level. Additionally, designing as many redundancies as possible in the delivery of care will help reduce medical errors. Primary healthcare providers should strongly consider investing in adequate doctor and nurse staffing, and improving their education related to the quality of service delivery to minimize clinical errors. This will lead to an increase in higher fixed costs, especially in the shorter time frame. This paper focuses additional attention needed to make a sound technical and business case for implementing six sigma tools to eliminate medical errors that will enable hospital managers to increase their hospital's profitability in the long run and also ensure patient safety.

  3. Systematic Procedural Error

    National Research Council Canada - National Science Library

    Byrne, Michael D

    2006-01-01

    .... This problem has received surprisingly little attention from cognitive psychologists. The research summarized here examines such errors in some detail both empirically and through computational cognitive modeling...

  4. Human errors and mistakes

    International Nuclear Information System (INIS)

    Wahlstroem, B.

    1993-01-01

    Human errors have a major contribution to the risks for industrial accidents. Accidents have provided important lesson making it possible to build safer systems. In avoiding human errors it is necessary to adapt the systems to their operators. The complexity of modern industrial systems is however increasing the danger of system accidents. Models of the human operator have been proposed, but the models are not able to give accurate predictions of human performance. Human errors can never be eliminated, but their frequency can be decreased by systematic efforts. The paper gives a brief summary of research in human error and it concludes with suggestions for further work. (orig.)

  5. Medication Administration Errors Involving Paediatric In-Patients in a ...

    African Journals Online (AJOL)

    The drug mostly associated with error was gentamicin with 29 errors (1.2 %). Conclusion: During the study, a high frequency of error was observed. There is a need to modify the way information is handled and shared by professionals as wrong time error was the most implicated error. Attention should also be given to IV ...

  6. Child and family experiences with inborn errors of metabolism: a qualitative interview study with representatives of patient groups.

    Science.gov (United States)

    Khangura, Sara D; Tingley, Kylie; Chakraborty, Pranesh; Coyle, Doug; Kronick, Jonathan B; Laberge, Anne-Marie; Little, Julian; Miller, Fiona A; Mitchell, John J; Prasad, Chitra; Siddiq, Shabnaz; Siriwardena, Komudi; Sparkes, Rebecca; Speechley, Kathy N; Stockler, Sylvia; Trakadis, Yannis; Wilson, Brenda J; Wilson, Kumanan; Potter, Beth K

    2016-01-01

    Patient-centered health care for children with inborn errors of metabolism (IEM) and their families is important and requires an understanding of patient experiences, needs, and priorities. IEM-specific patient groups have emerged as important voices within these rare disease communities and are uniquely positioned to contribute to this understanding. We conducted qualitative interviews with IEM patient group representatives to increase understanding of patient and family experiences, needs, and priorities and inform patient-centered research and care. We developed a sampling frame of patient groups representing IEM disease communities from Canada, the United States, and United Kingdom. With consent, we interviewed participants to explore their views on experiences, needs, and outcomes that are most important to children with IEM and their families. We analyzed the data using a qualitative descriptive approach to identify key themes and sub-themes. We interviewed 18 organizational representatives between February 28 and September 17, 2014, representing 16 IEMs and/or disease categories. Twelve participants voluntarily self-identified as parents and/or were themselves patients. Three key themes emerged from the coded data: managing the uncertainty associated with raising and caring for a child with a rare disease; challenges associated with the affected child's life transitions, and; the collective struggle for improved outcomes and interventions that rare disease communities navigate. Health care providers can support children with IEM and their families by acknowledging and reducing uncertainty, supporting families through children's life transitions, and contributing to rare disease communities' progress toward improved interventions, experiences, and outcomes.

  7. Study on relationship of performance shaping factor in human error probability with prevalent stress of PUSPATI TRIGA reactor operators

    Science.gov (United States)

    Rahim, Ahmad Nabil Bin Ab; Mohamed, Faizal; Farid, Mohd Fairus Abdul; Fazli Zakaria, Mohd; Sangau Ligam, Alfred; Ramli, Nurhayati Binti

    2018-01-01

    Human factor can be affected by prevalence stress measured using Depression, Anxiety and Stress Scale (DASS). From the respondents feedback can be summarized that the main factor causes the highest prevalence stress is due to the working conditions that require operators to handle critical situation and make a prompt critical decisions. The relationship between the prevalence stress and performance shaping factors found that PSFFitness and PSFWork Process showed positive Pearson’s Correlation with the score of .763 and .826 while the level of significance, p = .028 and p = .012. These positive correlations with good significant values between prevalence stress and human performance shaping factor (PSF) related to fitness, work processes and procedures. The higher the stress level of the respondents, the higher the score of selected for the PSFs. This is due to the higher levels of stress lead to deteriorating physical health and cognitive also worsened. In addition, the lack of understanding in the work procedures can also be a factor that causes a growing stress. The higher these values will lead to the higher the probabilities of human error occur. Thus, monitoring the level of stress among operators RTP is important to ensure the safety of RTP.

  8. A study on the operator's errors of commission (EOC) in accident scenarios of nuclear power plants: methodology development and application

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Whan; Jung, Won Dea; Park, Jin Kyun; Kang, Da Il

    2003-04-01

    As the concern on the operator's inappropriate interventions, the so-called Errors Of Commission (EOCs), that can exacerbate the plant safety has been raised, much of interest in the identification and analysis of EOC events from the risk assessment perspective has been increased. Also, one of the items in need of improvement for the conventional PSA and HRA that consider only the system-demanding human actions is the inclusion of the operator's EOC events into the PSA model. In this study, we propose a methodology for identifying and analysing human errors of commission that might be occurring from the failures in situation assessment and decision making during accident progressions given an initiating event. In order to achieve this goal, the following research items have been performed: Firstly, we analysed the error causes or situations contributed to the occurrence of EOCs in several incidents/accidents of nuclear power plants. Secondly, limitations of the advanced HRAs in treating EOCs were reviewed, and a requirement for a new methodology for analysing EOCs was established. Thirdly, based on these accomplishments a methodology for identifying and analysing EOC events inducible from the failures in situation assessment and decision making was proposed and applied to all the accident sequences of YGN 3 and 4 NPP which resulted in the identification of about 10 EOC situations.

  9. Towards a systematic assessment of errors in diffusion Monte Carlo calculations of semiconductors: Case study of zinc selenide and zinc oxide

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jaehyung [Department of Mechanical Science and Engineering, 1206 W Green Street, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Wagner, Lucas K. [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Ertekin, Elif, E-mail: ertekin@illinois.edu [Department of Mechanical Science and Engineering, 1206 W Green Street, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); International Institute for Carbon Neutral Energy Research - WPI-I" 2CNER, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2015-12-14

    The fixed node diffusion Monte Carlo (DMC) method has attracted interest in recent years as a way to calculate properties of solid materials with high accuracy. However, the framework for the calculation of properties such as total energies, atomization energies, and excited state energies is not yet fully established. Several outstanding questions remain as to the effect of pseudopotentials, the magnitude of the fixed node error, and the size of supercell finite size effects. Here, we consider in detail the semiconductors ZnSe and ZnO and carry out systematic studies to assess the magnitude of the energy differences arising from controlled and uncontrolled approximations in DMC. The former include time step errors and supercell finite size effects for ground and optically excited states, and the latter include pseudopotentials, the pseudopotential localization approximation, and the fixed node approximation. We find that for these compounds, the errors can be controlled to good precision using modern computational resources and that quantum Monte Carlo calculations using Dirac-Fock pseudopotentials can offer good estimates of both cohesive energy and the gap of these systems. We do however observe differences in calculated optical gaps that arise when different pseudopotentials are used.

  10. Error-related anterior cingulate cortex activity and the prediction of conscious error awareness

    Directory of Open Access Journals (Sweden)

    Catherine eOrr

    2012-06-01

    Full Text Available Research examining the neural mechanisms associated with error awareness has consistently identified dorsal anterior cingulate activity (ACC as necessary but not predictive of conscious error detection. Two recent studies (Steinhauser and Yeung, 2010; Wessel et al. 2011 have found a contrary pattern of greater dorsal ACC activity (in the form of the error-related negativity during detected errors, but suggested that the greater activity may instead reflect task influences (e.g., response conflict, error probability and or individual variability (e.g., statistical power. We re-analyzed fMRI BOLD data from 56 healthy participants who had previously been administered the Error Awareness Task, a motor Go/No-go response inhibition task in which subjects make errors of commission of which they are aware (Aware errors, or unaware (Unaware errors. Consistent with previous data, the activity in a number of cortical regions was predictive of error awareness, including bilateral inferior parietal and insula cortices, however in contrast to previous studies, including our own smaller sample studies using the same task, error-related dorsal ACC activity was significantly greater during aware errors when compared to unaware errors. While the significantly faster RT for aware errors (compared to unaware was consistent with the hypothesis of higher response conflict increasing ACC activity, we could find no relationship between dorsal ACC activity and the error RT difference. The data suggests that individual variability in error awareness is associated with error-related dorsal ACC activity, and therefore this region may be important to conscious error detection, but it remains unclear what task and individual factors influence error awareness.

  11. Determination of fission products and actinides by inductively coupled plasma-mass spectrometry using isotope dilution analysis. A study of random and systematic errors

    International Nuclear Information System (INIS)

    Ignacio Garcia Alonso, Jose

    1995-01-01

    The theory of the propagation of errors (random and systematic) for isotope dilution analysis (IDA) has been applied to the analysis of fission products and actinide elements by inductively coupled plasma-mass spectrometry (ICP-MS). Systematic errors in ID-ICP-MS arising from mass-discrimination (mass bias), detector non-linearity and isobaric interferences in the measured isotopes have to be corrected for in order to achieve accurate results. The mass bias factor and the detector dead-time can be determined by using natural elements with well-defined isotope abundances. A combined method for the simultaneous determination of both factors is proposed. On the other hand, isobaric interferences for some fission products and actinides cannot be eliminated using mathematical corrections (due to the unknown isotope abundances in the sample) and a chemical separation is necessary. The theory for random error propagation in IDA has been applied to the determination of non-natural elements by ICP-MS taking into account all possible sources of uncertainty with pulse counting detection. For the analysis of fission products, the selection of the right spike isotope composition and spike to sample ratio can be performed by applying conventional random propagation theory. However, it has been observed that, in the experimental determination of the isotope abundances of the fission product elements to be determined, the correction for mass-discrimination and the correction for detector dead-time losses contribute to the total random uncertainty. For the instrument used in the experimental part of this study, it was found that the random uncertainty on the measured isotope ratios followed Poisson statistics for low counting rates whereas, for high counting rates, source instability was the main source of error

  12. TENDENCY OF PLAYERS IS TRIAL AND ERROR: CASE STUDY OF COGNITIVE CLASSIFICATION IN THE COGNITIVE SKILL GAMES

    Directory of Open Access Journals (Sweden)

    Moh. Aries Syufagi

    2012-07-01

    Full Text Available To assess the cognitive level of player ability is difficult; many instruments are potentially biased, unreliable, and invalid test. Whereas, in serious game is important to know the cognitive level. If the cognitive level can be measured well, the mastery learning can be achieved. Mastery learning is the core of the learning process in serious game. To classify the cognitive level of players, researchers propose a Cognitive Skill Game (CSG. CSG improves this cognitive concept to monitor how players interact with the game. This game employs Learning Vector Quantization (LVQ for optimizing the cognitive skill input classification of the player. Training data in LVQ use data observation from the teacher. Populations of cognitive skill classification in this research are pupils when playing the game. Mostly players cognitive skill game have cognitive skill category are Trial and Error. Some of them have Expert category, and a few included in the group carefully. Thus, the general level of skill of the player is still low. Untuk menilai tingkat kognitif dari kemampuan pemain sangatlah sulit; banyak instrumen yang berpotensi bias, tidak dapat diandalkan, dan merupakan tes yang tidak valid. Padahal, dalam serious game penting untuk mengetahui tingkat kognitif. Jika tingkat kognitif dapat diukur dengan baik, penguasaan pembelajaran dapat dicapai. Penguasaan belajar adalah inti dari proses belajar dalam serious game. Untuk mengklasifikasikan tingkat kognitif pemain, kami mengusulkan Cognitive Skill Game (CSG. CSG meningkatkan konsep kognitif untuk memantau bagaimana pemain berinteraksi dengan permainan. Permainan ini menggunakan Learning Vector Quantization (LVQ untuk mengoptimalkan input klasifikasi keterampilan kognitif pemain. Data trining dalam observasi LVQ menggunakan data dari guru. Populasi klasifikasi keterampilan kognitif dalam penelitian ini adalah siswa saat memainkan permainan. Sebagian besar pemain CSG berkategori keterampilan kognitif

  13. Action errors, error management, and learning in organizations.

    Science.gov (United States)

    Frese, Michael; Keith, Nina

    2015-01-03

    Every organization is confronted with errors. Most errors are corrected easily, but some may lead to negative consequences. Organizations often focus on error prevention as a single strategy for dealing with errors. Our review suggests that error prevention needs to be supplemented by error management--an approach directed at effectively dealing with errors after they have occurred, with the goal of minimizing negative and maximizing positive error consequences (examples of the latter are learning and innovations). After defining errors and related concepts, we review research on error-related processes affected by error management (error detection, damage control). Empirical evidence on positive effects of error management in individuals and organizations is then discussed, along with emotional, motivational, cognitive, and behavioral pathways of these effects. Learning from errors is central, but like other positive consequences, learning occurs under certain circumstances--one being the development of a mind-set of acceptance of human error.

  14. Comparison between calorimeter and HLNC errors

    International Nuclear Information System (INIS)

    Goldman, A.S.; De Ridder, P.; Laszlo, G.

    1991-01-01

    This paper summarizes an error analysis that compares systematic and random errors of total plutonium mass estimated for high-level neutron coincidence counter (HLNC) and calorimeter measurements. This task was part of an International Atomic Energy Agency (IAEA) study on the comparison of the two instruments to determine if HLNC measurement errors met IAEA standards and if the calorimeter gave ''significantly'' better precision. Our analysis was based on propagation of error models that contained all known sources of errors including uncertainties associated with plutonium isotopic measurements. 5 refs., 2 tabs

  15. Prevention of hospital payment errors and implications for case management: a study of nine hospitals with a high proportion of short-term admissions over time.

    Science.gov (United States)

    Hightower, Rebecca E

    2008-01-01

    Since the publication of the first analysis of Medicare payment error rates in 1998, the Office of Inspector General and the Centers for Medicare & Medicaid Services have focused resources on Medicare payment error prevention programs, now referred to as the Hospital Payment Monitoring Program. The purpose of the Hospital Payment Monitoring Program is to educate providers of Medicare Part A services in strategies to improve medical record documentation and decrease the potential for payment errors through appropriate claims completion. Although the payment error rates by state (and dollars paid in error) have decreased significantly, opportunities for improvement remain as demonstrated in this study of nine hospitals with a high proportion of short-term admissions over time. Previous studies by the Quality Improvement Organization had focused on inpatient stays of 1 day or less, a primary target due to the large amount of Medicare dollars spent on these admissions. Random review of Louisiana Medicare admissions revealed persistent medical record documentation and process issues regardless of length of stay as well as the opportunity for significant future savings to the Medicare Trust Fund. The purpose of this study was to determine whether opportunities for improvement in reduction of payment error continue to exist for inpatient admissions of greater than 1 day, despite focused education provided by Louisiana Health Care Review, the Louisiana Medicare Quality Improvement Organization, from 1999 to 2005, and to work individually with the nine selected hospitals to assist them in reducing the number of unnecessary short-term admissions and billing errors in each hospital by a minimum of 50% by the end of the study period. Inpatient Short-Term Acute Care Hospitals. A sample of claims for short-term stays (defined as an inpatient admission with a length of stay of 3 days or less excluding deaths, interim bills for those still a patient and those who left against

  16. Spacecraft and propulsion technician error

    Science.gov (United States)

    Schultz, Daniel Clyde

    Commercial aviation and commercial space similarly launch, fly, and land passenger vehicles. Unlike aviation, the U.S. government has not established maintenance policies for commercial space. This study conducted a mixed methods review of 610 U.S. space launches from 1984 through 2011, which included 31 failures. An analysis of the failure causal factors showed that human error accounted for 76% of those failures, which included workmanship error accounting for 29% of the failures. With the imminent future of commercial space travel, the increased potential for the loss of human life demands that changes be made to the standardized procedures, training, and certification to reduce human error and failure rates. Several recommendations were made by this study to the FAA's Office of Commercial Space Transportation, space launch vehicle operators, and maintenance technician schools in an effort to increase the safety of the space transportation passengers.

  17. The effect of the TIM program (Transfer ICU Medication reconciliation) on medication transfer errors in two Dutch intensive care units : Design of a prospective 8-month observational study with a before and after period

    NARCIS (Netherlands)

    B.E. Bosma (Bertha); E. Meuwese (Edmé); S.S. Tan (Siok Swan); J. van Bommel (Jasper); Melief, P.H.G.J. (Piet Herman Gerard Jan); N.G.M. Hunfeld (Nicola); P.M.L.A. van den Bemt (Patricia)

    2017-01-01

    markdownabstract__Background:__ The transfer of patients to and from the Intensive Care Unit (ICU) is prone to medication errors. The aim of the present study is to determine whether the number of medication errors at ICU admission and discharge and the associated potential harm and costs are

  18. Errors and violations

    International Nuclear Information System (INIS)

    Reason, J.

    1988-01-01

    This paper is in three parts. The first part summarizes the human failures responsible for the Chernobyl disaster and argues that, in considering the human contribution to power plant emergencies, it is necessary to distinguish between: errors and violations; and active and latent failures. The second part presents empirical evidence, drawn from driver behavior, which suggest that errors and violations have different psychological origins. The concluding part outlines a resident pathogen view of accident causation, and seeks to identify the various system pathways along which errors and violations may be propagated

  19. Analysis of errors in forensic science

    Directory of Open Access Journals (Sweden)

    Mingxiao Du

    2017-01-01

    Full Text Available Reliability of expert testimony is one of the foundations of judicial justice. Both expert bias and scientific errors affect the reliability of expert opinion, which in turn affects the trustworthiness of the findings of fact in legal proceedings. Expert bias can be eliminated by replacing experts; however, it may be more difficult to eliminate scientific errors. From the perspective of statistics, errors in operation of forensic science include systematic errors, random errors, and gross errors. In general, process repetition and abiding by the standard ISO/IEC:17025: 2005, general requirements for the competence of testing and calibration laboratories, during operation are common measures used to reduce errors that originate from experts and equipment, respectively. For example, to reduce gross errors, the laboratory can ensure that a test is repeated several times by different experts. In applying for forensic principles and methods, the Federal Rules of Evidence 702 mandate that judges consider factors such as peer review, to ensure the reliability of the expert testimony. As the scientific principles and methods may not undergo professional review by specialists in a certain field, peer review serves as an exclusive standard. This study also examines two types of statistical errors. As false-positive errors involve a higher possibility of an unfair decision-making, they should receive more attention than false-negative errors.

  20. Error management process for power stations

    International Nuclear Information System (INIS)

    Hirotsu, Yuko; Takeda, Daisuke; Fujimoto, Junzo; Nagasaka, Akihiko

    2016-01-01

    The purpose of this study is to establish 'error management process for power stations' for systematizing activities for human error prevention and for festering continuous improvement of these activities. The following are proposed by deriving concepts concerning error management process from existing knowledge and realizing them through application and evaluation of their effectiveness at a power station: an entire picture of error management process that facilitate four functions requisite for maraging human error prevention effectively (1. systematizing human error prevention tools, 2. identifying problems based on incident reports and taking corrective actions, 3. identifying good practices and potential problems for taking proactive measures, 4. prioritizeng human error prevention tools based on identified problems); detail steps for each activity (i.e. developing an annual plan for human error prevention, reporting and analyzing incidents and near misses) based on a model of human error causation; procedures and example of items for identifying gaps between current and desired levels of executions and outputs of each activity; stages for introducing and establishing the above proposed error management process into a power station. By giving shape to above proposals at a power station, systematization and continuous improvement of activities for human error prevention in line with the actual situation of the power station can be expected. (author)

  1. Analysis of error patterns in clinical radiotherapy

    International Nuclear Information System (INIS)

    Macklis, Roger; Meier, Tim; Barrett, Patricia; Weinhous, Martin

    1996-01-01

    Purpose: Until very recently, prescription errors and adverse treatment events have rarely been studied or reported systematically in oncology. We wished to understand the spectrum and severity of radiotherapy errors that take place on a day-to-day basis in a high-volume academic practice and to understand the resource needs and quality assurance challenges placed on a department by rapid upswings in contract-based clinical volumes requiring additional operating hours, procedures, and personnel. The goal was to define clinical benchmarks for operating safety and to detect error-prone treatment processes that might function as 'early warning' signs. Methods: A multi-tiered prospective and retrospective system for clinical error detection and classification was developed, with formal analysis of the antecedents and consequences of all deviations from prescribed treatment delivery, no matter how trivial. A department-wide record-and-verify system was operational during this period and was used as one method of treatment verification and error detection. Brachytherapy discrepancies were analyzed separately. Results: During the analysis year, over 2000 patients were treated with over 93,000 individual fields. A total of 59 errors affecting a total of 170 individual treated fields were reported or detected during this period. After review, all of these errors were classified as Level 1 (minor discrepancy with essentially no potential for negative clinical implications). This total treatment delivery error rate (170/93, 332 or 0.18%) is significantly better than corresponding error rates reported for other hospital and oncology treatment services, perhaps reflecting the relatively sophisticated error avoidance and detection procedures used in modern clinical radiation oncology. Error rates were independent of linac model and manufacturer, time of day (normal operating hours versus late evening or early morning) or clinical machine volumes. There was some relationship to

  2. Characteristics of pediatric chemotherapy medication errors in a national error reporting database.

    Science.gov (United States)

    Rinke, Michael L; Shore, Andrew D; Morlock, Laura; Hicks, Rodney W; Miller, Marlene R

    2007-07-01

    Little is known regarding chemotherapy medication errors in pediatrics despite studies suggesting high rates of overall pediatric medication errors. In this study, the authors examined patterns in pediatric chemotherapy errors. The authors queried the United States Pharmacopeia MEDMARX database, a national, voluntary, Internet-accessible error reporting system, for all error reports from 1999 through 2004 that involved chemotherapy medications and patients aged error reports, 85% reached the patient, and 15.6% required additional patient monitoring or therapeutic intervention. Forty-eight percent of errors originated in the administering phase of medication delivery, and 30% originated in the drug-dispensing phase. Of the 387 medications cited, 39.5% were antimetabolites, 14.0% were alkylating agents, 9.3% were anthracyclines, and 9.3% were topoisomerase inhibitors. The most commonly involved chemotherapeutic agents were methotrexate (15.3%), cytarabine (12.1%), and etoposide (8.3%). The most common error types were improper dose/quantity (22.9% of 327 cited error types), wrong time (22.6%), omission error (14.1%), and wrong administration technique/wrong route (12.2%). The most common error causes were performance deficit (41.3% of 547 cited error causes), equipment and medication delivery devices (12.4%), communication (8.8%), knowledge deficit (6.8%), and written order errors (5.5%). Four of the 5 most serious errors occurred at community hospitals. Pediatric chemotherapy errors often reached the patient, potentially were harmful, and differed in quality between outpatient and inpatient areas. This study indicated which chemotherapeutic agents most often were involved in errors and that administering errors were common. Investigation is needed regarding targeted medication administration safeguards for these high-risk medications. Copyright (c) 2007 American Cancer Society.

  3. Sensation seeking and error processing.

    Science.gov (United States)

    Zheng, Ya; Sheng, Wenbin; Xu, Jing; Zhang, Yuanyuan

    2014-09-01

    Sensation seeking is defined by a strong need for varied, novel, complex, and intense stimulation, and a willingness to take risks for such experience. Several theories propose that the insensitivity to negative consequences incurred by risks is one of the hallmarks of sensation-seeking behaviors. In this study, we investigated the time course of error processing in sensation seeking by recording event-related potentials (ERPs) while high and low sensation seekers performed an Eriksen flanker task. Whereas there were no group differences in ERPs to correct trials, sensation seeking was associated with a blunted error-related negativity (ERN), which was female-specific. Further, different subdimensions of sensation seeking were related to ERN amplitude differently. These findings indicate that the relationship between sensation seeking and error processing is sex-specific. Copyright © 2014 Society for Psychophysiological Research.

  4. Reward positivity: Reward prediction error or salience prediction error?

    Science.gov (United States)

    Heydari, Sepideh; Holroyd, Clay B

    2016-08-01

    The reward positivity is a component of the human ERP elicited by feedback stimuli in trial-and-error learning and guessing tasks. A prominent theory holds that the reward positivity reflects a reward prediction error signal that is sensitive to outcome valence, being larger for unexpected positive events relative to unexpected negative events (Holroyd & Coles, 2002). Although the theory has found substantial empirical support, most of these studies have utilized either monetary or performance feedback to test the hypothesis. However, in apparent contradiction to the theory, a recent study found that unexpected physical punishments also elicit the reward positivity (Talmi, Atkinson, & El-Deredy, 2013). The authors of this report argued that the reward positivity reflects a salience prediction error rather than a reward prediction error. To investigate this finding further, in the present study participants navigated a virtual T maze and received feedback on each trial under two conditions. In a reward condition, the feedback indicated that they would either receive a monetary reward or not and in a punishment condition the feedback indicated that they would receive a small shock or not. We found that the feedback stimuli elicited a typical reward positivity in the reward condition and an apparently delayed reward positivity in the punishment condition. Importantly, this signal was more positive to the stimuli that predicted the omission of a possible punishment relative to stimuli that predicted a forthcoming punishment, which is inconsistent with the salience hypothesis. © 2016 Society for Psychophysiological Research.

  5. Help prevent hospital errors

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000618.htm Help prevent hospital errors To use the sharing features ... in the hospital. If You Are Having Surgery, Help Keep Yourself Safe Go to a hospital you ...

  6. Pedal Application Errors

    Science.gov (United States)

    2012-03-01

    This project examined the prevalence of pedal application errors and the driver, vehicle, roadway and/or environmental characteristics associated with pedal misapplication crashes based on a literature review, analysis of news media reports, a panel ...

  7. Rounding errors in weighing

    International Nuclear Information System (INIS)

    Jeach, J.L.

    1976-01-01

    When rounding error is large relative to weighing error, it cannot be ignored when estimating scale precision and bias from calibration data. Further, if the data grouping is coarse, rounding error is correlated with weighing error and may also have a mean quite different from zero. These facts are taken into account in a moment estimation method. A copy of the program listing for the MERDA program that provides moment estimates is available from the author. Experience suggests that if the data fall into four or more cells or groups, it is not necessary to apply the moment estimation method. Rather, the estimate given by equation (3) is valid in this instance. 5 tables

  8. Spotting software errors sooner

    International Nuclear Information System (INIS)

    Munro, D.

    1989-01-01

    Static analysis is helping to identify software errors at an earlier stage and more cheaply than conventional methods of testing. RTP Software's MALPAS system also has the ability to check that a code conforms to its original specification. (author)

  9. Errors in energy bills

    International Nuclear Information System (INIS)

    Kop, L.

    2001-01-01

    On request, the Dutch Association for Energy, Environment and Water (VEMW) checks the energy bills for her customers. It appeared that in the year 2000 many small, but also big errors were discovered in the bills of 42 businesses

  10. Medical Errors Reduction Initiative

    National Research Council Canada - National Science Library

    Mutter, Michael L

    2005-01-01

    The Valley Hospital of Ridgewood, New Jersey, is proposing to extend a limited but highly successful specimen management and medication administration medical errors reduction initiative on a hospital-wide basis...

  11. The surveillance error grid.

    Science.gov (United States)

    Klonoff, David C; Lias, Courtney; Vigersky, Robert; Clarke, William; Parkes, Joan Lee; Sacks, David B; Kirkman, M Sue; Kovatchev, Boris

    2014-07-01

    Currently used error grids for assessing clinical accuracy of blood glucose monitors are based on out-of-date medical practices. Error grids have not been widely embraced by regulatory agencies for clearance of monitors, but this type of tool could be useful for surveillance of the performance of cleared products. Diabetes Technology Society together with representatives from the Food and Drug Administration, the American Diabetes Association, the Endocrine Society, and the Association for the Advancement of Medical Instrumentation, and representatives of academia, industry, and government, have developed a new error grid, called the surveillance error grid (SEG) as a tool to assess the degree of clinical risk from inaccurate blood glucose (BG) monitors. A total of 206 diabetes clinicians were surveyed about the clinical risk of errors of measured BG levels by a monitor. The impact of such errors on 4 patient scenarios was surveyed. Each monitor/reference data pair was scored and color-coded on a graph per its average risk rating. Using modeled data representative of the accuracy of contemporary meters, the relationships between clinical risk and monitor error were calculated for the Clarke error grid (CEG), Parkes error grid (PEG), and SEG. SEG action boundaries were consistent across scenarios, regardless of whether the patient was type 1 or type 2 or using insulin or not. No significant differences were noted between responses of adult/pediatric or 4 types of clinicians. Although small specific differences in risk boundaries between US and non-US clinicians were noted, the panel felt they did not justify separate grids for these 2 types of clinicians. The data points of the SEG were classified in 15 zones according to their assigned level of risk, which allowed for comparisons with the classic CEG and PEG. Modeled glucose monitor data with realistic self-monitoring of blood glucose errors derived from meter testing experiments plotted on the SEG when compared to

  12. Design for Error Tolerance

    DEFF Research Database (Denmark)

    Rasmussen, Jens

    1983-01-01

    An important aspect of the optimal design of computer-based operator support systems is the sensitivity of such systems to operator errors. The author discusses how a system might allow for human variability with the use of reversibility and observability.......An important aspect of the optimal design of computer-based operator support systems is the sensitivity of such systems to operator errors. The author discusses how a system might allow for human variability with the use of reversibility and observability....

  13. The Study on Bone Mineral Density Measurement Error in Accordance with Change in ROI by Utilizing Dual Energy X-ray Absorptiometry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yun Hong [Dept. of Diagnostic Radiology, Korea University Guro Hospital, Seoul (Korea, Republic of); Lee, In Ja [Dept. of Radiological Technology, Dongnam Health College, Suwon (Korea, Republic of); Yong, Hyung Jin [Dept. of Medicine Physics, The Graduate School of Biomedical Science Korea University, Seoul (Korea, Republic of)

    2012-03-15

    Dual Energy X-ray Absorptiometry(DEXA) is commonly used to diagnose Osteoporosis. The errors of DEXA bone density operation are caused by operator, bone mineral density meter, blood testing, patient. We focus on operator error then study about how much influence operator's region of intest(ROI) in bone testing result. During from March to July in 2011. 50 patients ware selected respectively from 30, 40, 50, 60, and 70 age groups who came to Korea University Medical Center(KUMC) for their Osteoporosis treatment. A-test was performed with usually ROI and B-test was performed with most widely ROI. Then, We compare A-test and B-test for find maximum difference of T-score error which occurred operator ROI controlling. Standard deviation of T-score of B-test showed 0.1 higher then A-test in femur neck. Standard deviation of B-test showed 0.2 higher then A-test in Ward's area which in Greater trocanter and Inter trocanter. Standard deviation of B-test showed 0,1 lower then A-test in L-1. Bone density testing about Two hundred patients results are as follow. When operator ROI was changed wider than normal ROI, bone density of femur was measured more higher but bone density of L-spine was measured more lower then normal bone density. That means, sometime DEXA bone density testing result is dependent by operator ROI controlling. This is relevant with the patient's medicine and health insurance, thus, tester always keep the size of ROI for to prevent any problem in the patient.

  14. Apologies and Medical Error

    Science.gov (United States)

    2008-01-01

    One way in which physicians can respond to a medical error is to apologize. Apologies—statements that acknowledge an error and its consequences, take responsibility, and communicate regret for having caused harm—can decrease blame, decrease anger, increase trust, and improve relationships. Importantly, apologies also have the potential to decrease the risk of a medical malpractice lawsuit and can help settle claims by patients. Patients indicate they want and expect explanations and apologies after medical errors and physicians indicate they want to apologize. However, in practice, physicians tend to provide minimal information to patients after medical errors and infrequently offer complete apologies. Although fears about potential litigation are the most commonly cited barrier to apologizing after medical error, the link between litigation risk and the practice of disclosure and apology is tenuous. Other barriers might include the culture of medicine and the inherent psychological difficulties in facing one’s mistakes and apologizing for them. Despite these barriers, incorporating apology into conversations between physicians and patients can address the needs of both parties and can play a role in the effective resolution of disputes related to medical error. PMID:18972177

  15. Reporting Errors in Siblings’ Survival Histories and Their Impact on Adult Mortality Estimates: Results From a Record Linkage Study in Senegal

    Science.gov (United States)

    Helleringer, Stéphane; Pison, Gilles; Kanté, Almamy M.; Duthé, Géraldine; Andro, Armelle

    2014-01-01

    Estimates of adult mortality in countries with limited vital registration (e.g., sub-Saharan Africa) are often derived from information about the survival of a respondent’s siblings. We evaluated the completeness and accuracy of such data through a record linkage study conducted in Bandafassi, located in southeastern Senegal. We linked at the individual level retrospective siblings’ survival histories (SSH) reported by female respondents (n = 268) to prospective mortality data and genealogies collected through a health and demographic surveillance system (HDSS). Respondents often reported inaccurate lists of siblings. Additions to these lists were uncommon, but omissions were frequent: respondents omitted 3.8 % of their live sisters, 9.1 % of their deceased sisters, and 16.6 % of their sisters who had migrated out of the DSS area. Respondents underestimated the age at death of the siblings they reported during the interview, particularly among siblings who had died at older ages (≥45 years). Restricting SSH data to person-years and events having occurred during a recent reference period reduced list errors but not age and date errors. Overall, SSH data led to a 20 % underestimate of 45q15 relative to HDSS data. Our study suggests new quality improvement strategies for SSH data and demonstrates the potential use of HDSS data for the validation of “unconventional” demographic techniques. PMID:24493063

  16. Reporting errors in siblings' survival histories and their impact on adult mortality estimates: results from a record linkage study in Senegal.

    Science.gov (United States)

    Helleringer, Stéphane; Pison, Gilles; Kanté, Almamy M; Duthé, Géraldine; Andro, Armelle

    2014-04-01

    Estimates of adult mortality in countries with limited vital registration (e.g., sub-Saharan Africa) are often derived from information about the survival of a respondent's siblings. We evaluated the completeness and accuracy of such data through a record linkage study conducted in Bandafassi, located in southeastern Senegal. We linked at the individual level retrospective siblings' survival histories (SSH) reported by female respondents (n = 268) to prospective mortality data and genealogies collected through a health and demographic surveillance system (HDSS). Respondents often reported inaccurate lists of siblings. Additions to these lists were uncommon, but omissions were frequent: respondents omitted 3.8 % of their live sisters, 9.1 % of their deceased sisters, and 16.6 % of their sisters who had migrated out of the DSS area. Respondents underestimated the age at death of the siblings they reported during the interview, particularly among siblings who had died at older ages (≥45 years). Restricting SSH data to person-years and events having occurred during a recent reference period reduced list errors but not age and date errors. Overall, SSH data led to a 20 % underestimate of 45 q 15 relative to HDSS data. Our study suggests new quality improvement strategies for SSH data and demonstrates the potential use of HDSS data for the validation of "unconventional" demographic techniques.

  17. Validating Domains of Patient Contextual Factors Essential to Preventing Contextual Errors: A Qualitative Study Conducted at Chicago Area Veterans Health Administration Sites.

    Science.gov (United States)

    Binns-Calvey, Amy E; Malhiot, Alex; Kostovich, Carol T; LaVela, Sherri L; Stroupe, Kevin; Gerber, Ben S; Burkhart, Lisa; Weiner, Saul J; Weaver, Frances M

    2017-09-01

    "Patient context" indicates patient circumstances and characteristics or states that are essential to address when planning patient care. Specific patient "contextual factors," if overlooked, result in an inappropriate plan of care, a medical error termed a "contextual error." The myriad contextual factors that constitute patient context have been grouped into broad domains to create a taxonomy of challenges to consider when planning care. This study sought to validate a previously identified list of contextual domains. This qualitative study used directed content analysis. In 2014, 19 Department of Veterans Affairs (VA) providers (84% female) and 49 patients (86% male) from two VA medical centers and four outpatient clinics in the Chicago area participated in semistructured interviews and focus groups. Topics included patient-specific, community, and resource-related factors that affect patients' abilities to manage their care. Transcripts were analyzed with a previously identified list of contextual domains as a framework. Analysis of responses revealed that patients and providers identified the same 10 domains previously published, plus 3 additional ones. Based on comments made by patients and providers, the authors created a revised list of 12 domains from themes that emerged. Six pertain to patient circumstances such as access to care and financial situation, and 6 to patient characteristics/states including skills, abilities, and knowledge. Contextual factors in patients' lives may be essential to address for effective care planning. The rubric developed can serve as a "contextual differential" for clinicians to consider when addressing challenges patients face when planning their care.

  18. A Monte Carlo Study of Levene's Test of Homogeneity of Variance: Empirical Frequencies of Type I Error in Normal Distributions.

    Science.gov (United States)

    Neel, John H.; Stallings, William M.

    An influential statistics test recommends a Levene text for homogeneity of variance. A recent note suggests that Levene's test is upwardly biased for small samples. Another report shows inflated Alpha estimates and low power. Neither study utilized more than two sample sizes. This Monte Carlo study involved sampling from a normal population for…

  19. A Mobile Device App to Reduce Medication Errors and Time to Drug Delivery During Pediatric Cardiopulmonary Resuscitation: Study Protocol of a Multicenter Randomized Controlled Crossover Trial.

    Science.gov (United States)

    Siebert, Johan N; Ehrler, Frederic; Lovis, Christian; Combescure, Christophe; Haddad, Kevin; Gervaix, Alain; Manzano, Sergio

    2017-08-22

    During pediatric cardiopulmonary resuscitation (CPR), vasoactive drug preparation for continuous infusions is complex and time-consuming. The need for individual specific weight-based drug dose calculation and preparation places children at higher risk than adults for medication errors. Following an evidence-based and ergonomic driven approach, we developed a mobile device app called Pediatric Accurate Medication in Emergency Situations (PedAMINES), intended to guide caregivers step-by-step from preparation to delivery of drugs requiring continuous infusion. In a prior single center randomized controlled trial, medication errors were reduced from 70% to 0% by using PedAMINES when compared with conventional preparation methods. The purpose of this study is to determine whether the use of PedAMINES in both university and smaller hospitals reduces medication dosage errors (primary outcome), time to drug preparation (TDP), and time to drug delivery (TDD) (secondary outcomes) during pediatric CPR when compared with conventional preparation methods. This is a multicenter, prospective, randomized controlled crossover trial with 2 parallel groups comparing PedAMINES with a conventional and internationally used drug infusion rate table in the preparation of continuous drug infusion. The evaluation setting uses a simulation-based pediatric CPR cardiac arrest scenario with a high-fidelity manikin. The study involving 120 certified nurses (sample size) will take place in the resuscitation rooms of 3 tertiary pediatric emergency departments and 3 smaller hospitals. After epinephrine-induced return of spontaneous circulation, nurses will be asked to prepare a continuous infusion of dopamine using either PedAMINES (intervention group) or the infusion table (control group) and then prepare a continuous infusion of norepinephrine by crossing the procedure. The primary outcome is the medication dosage error rate. The secondary outcome is the time in seconds elapsed since the oral

  20. Sensitivity of HER-2/neu antibodies in archival tissue samples: potential source of error in immunohistochemical studies of oncogene expression.

    Science.gov (United States)

    Press, M F; Hung, G; Godolphin, W; Slamon, D J

    1994-05-15

    HER-2/neu oncogene amplification and overexpression of breast cancer tissue has been correlated with poor prognosis in women with both node-positive and node-negative disease. However, several studies have not confirmed this association. Review of these studies reveals the presence of considerable methodological variability including differences in study size, follow-up time, techniques and reagents. The majority of papers with clinical follow-up information are immunohistochemical studies using archival, paraffin-embedded breast cancers, and a variety of HER-2/neu antibodies have been used in these studies. Very little information, however, is available about the ability of the antibodies to detect overexpression following tissue processing for paraffin-embedding. Therefore, a series of antibodies, reported in the literature or commercially available, were evaluated to assess their sensitivity and specificity as immunohistochemical reagents. Paraffin-embedded samples of 187 breast cancers, previously characterized as frozen specimens for HER-2/neu amplification by Southern blot and for overexpression by Northern blot, Western blot, and immunohistochemistry, were used. Two multitumor paraffin-embedded tissue blocks were prepared from the previously analyzed breast cancers as a panel of cases to test a series of previously studied and/or commercially available anti-HER-2/neu antibodies. Immunohistochemical staining results obtained with 7 polyclonal and 21 monoclonal antibodies in sections from paraffin-embedded blocks of these breast cancers were compared. The ability of these antibodies to detect overexpression was extremely variable, providing an important explantation for the variable overexpression rate reported in the literature.

  1. Study of systematic errors in the determination of total Hg levels in the range -5% in inorganic and organic matrices with two reliable spectrometrical determination procedures

    International Nuclear Information System (INIS)

    Kaiser, G.; Goetz, D.; Toelg, G.; Max-Planck-Institut fuer Metallforschung, Stuttgart; Knapp, G.; Maichin, B.; Spitzy, H.

    1978-01-01

    In the determiniation of Hg at ng/g and pg/g levels systematic errors are due to faults in the analytical methods such as intake, preparation and decomposition of a sample. The sources of these errors have been studied both with 203 Hg-radiotracer techniques and two multi-stage procedures developed for the determiniation of trace levels. The emission spectrometrie (OES-MIP) procedure includes incineration of the sample in a microwave induced oxygen plasma (MIP), the isolation and enrichment on a gold absorbent and its excitation in an argon plasma (MIP). The emitted Hg-radiation (253,7 nm) is evaluated photometrically with a semiconductor element. The detection limit of the OES-MIP procedure was found to be 0,01 ng, the coefficient of variation 5% for 1 ng Hg. The second procedure combines a semi-automated wet digestion method (HCLO 3 /HNO 3 ) with a reduction-aeration (ascorbic acid/SnCl 2 ), and the flameless atomic absorption technique (253,7 nm). The detection limit of this procedure was found to be 0,5 ng, the coefficient of variation 5% for 5 ng Hg. (orig.) [de

  2. The potentiometric and laser RAMAN study of the hydrolysis of uranyl chloride under physiological conditions and the effect of systematic and random errors on the hydrolysis constants

    International Nuclear Information System (INIS)

    Deschenes, L.L.; Kramer, G.H.; Monserrat, K.J.; Robinson, P.A.

    1986-12-01

    The hydrolysis of uranyl ions in 0.15 mol/L (Na)C1 solution at 37 degrees Celsius has been studied by potentiometric titration. The results were consistent with the formation of (UO 2 ) 2 (OH) 2 , (UO 2 ) 3 (OH) 4 , (UO 2 ) 3 (OH) 5 and (UO 2 ) 4 (OH) 7 . The stability constants, which were evaluated using a version of MINIQUAD, were found to be: log β 22 = -5.693 ± 0.007, log β 34 = -11.499 ± 0.024, log β 35 = -16.001 ± 0.050, log β 47 = -21.027 ± 0.051. Laser Raman spectroscopy has been used to identify the products including (UO 2 ) 4 (OH) 7 species. The difficulties in identifying the chemical species in solution and the effect of small errors on this selection has also been investigated by computer simulation. The results clearly indicate that small errors can lead to the selection of species that may not exist

  3. Ergonomic study of biorhythm effect on the 62 occurrence of human errors and accidents in automobile manufacturing industry

    Directory of Open Access Journals (Sweden)

    2012-03-01

    Conclusion: This study showed that the frequency of accidents in critical days and negative section of physical cycle was more than expected. Also the frequency of accidents in critical days and negative section of emotional and intellectual cycle was less than expected. Due to the physical nature of the work activities in the automobile manufacturing industry can be stated that the study showed that in physical work activities, frequency of accidents in critical days and negative section of physical cycle in which the person is not physically ready to do the job was more than expected.

  4. Real-time beam monitoring for error detection in IMRT plans and impact on dose-volume histograms. A multi-center study

    Energy Technology Data Exchange (ETDEWEB)

    Marrazzo, Livia; Arilli, Chiara; Casati, Marta [Careggi University Hospital, Medical Physic Unit, Florence (Italy); Pasler, Marlies [Lake Constance Radiation Oncology Center, Singen-Friedrichshafen (Germany); Kusters, Martijn; Canters, Richard [Radboud University Medical Center, Department of Radiation Oncology, Nijmegen (Netherlands); Fedeli, Luca; Calusi, Silvia [University of Florence, Department of Experimental and Clinical Biomedical Sciences ' ' Mario Serio' ' , Florence (Italy); Talamonti, Cinzia; Pallotta, Stefania [Careggi University Hospital, Medical Physic Unit, Florence (Italy); University of Florence, Department of Experimental and Clinical Biomedical Sciences ' ' Mario Serio' ' , Florence (Italy); Simontacchi, Gabriele [Careggi University Hospital, Radiation Oncology Unit, Florence (Italy); Livi, Lorenzo [University of Florence, Department of Experimental and Clinical Biomedical Sciences ' ' Mario Serio' ' , Florence (Italy); Careggi University Hospital, Radiation Oncology Unit, Florence (Italy)

    2018-03-15

    This study aimed to test the sensitivity of a transmission detector for online dose monitoring of intensity-modulated radiation therapy (IMRT) for detecting small delivery errors. Furthermore, the correlation of changes in detector output induced by small delivery errors with other metrics commonly employed to quantify the deviations between calculated and delivered dose distributions was investigated. Transmission detector measurements were performed at three institutions. Seven types of errors were induced in nine clinical step-and-shoot (S and S) IMRT plans by modifying the number of monitor units (MU) and introducing small deviations in leaf positions. Signal reproducibility was investigated for short- and long-term stability. Calculated dose distributions were compared in terms of γ passing rates and dose-volume histogram (DVH) metrics (e.g., D{sub mean}, D{sub x%}, V{sub x%}). The correlation between detector signal variations, γ passing rates, and DVH parameters was investigated. Both short- and long-term reproducibility was within 1%. Dose variations down to 1 MU (∇signal 1.1 ± 0.4%) as well as changes in field size and positions down to 1 mm (∇signal 2.6 ± 1.0%) were detected, thus indicating high error-detection sensitivity. A moderate correlation of detector signal was observed with γ passing rates (R{sup 2} = 0.57-0.70), while a good correlation was observed with DVH metrics (R{sup 2} = 0.75-0.98). The detector is capable of detecting small delivery errors in MU and leaf positions, and is thus a highly sensitive dose monitoring device for S and S IMRT for clinical practice. The results of this study indicate a good correlation of detector signal with DVH metrics; therefore, clinical action levels can be defined based on the presented data. (orig.) [German] In dieser Arbeit wurde die Sensitivitaet bezueglich der Fehlererkennung eines Transmissionsdetektors fuer die Online-Dosisueberwachung von intensitaetsmodulierter Strahlentherapie (IMRT

  5. Collection of offshore human error probability data

    International Nuclear Information System (INIS)

    Basra, Gurpreet; Kirwan, Barry

    1998-01-01

    Accidents such as Piper Alpha have increased concern about the effects of human errors in complex systems. Such accidents can in theory be predicted and prevented by risk assessment, and in particular human reliability assessment (HRA), but HRA ideally requires qualitative and quantitative human error data. A research initiative at the University of Birmingham led to the development of CORE-DATA, a Computerised Human Error Data Base. This system currently contains a reasonably large number of human error data points, collected from a variety of mainly nuclear-power related sources. This article outlines a recent offshore data collection study, concerned with collecting lifeboat evacuation data. Data collection methods are outlined and a selection of human error probabilities generated as a result of the study are provided. These data give insights into the type of errors and human failure rates that could be utilised to support offshore risk analyses

  6. Compact disk error measurements

    Science.gov (United States)

    Howe, D.; Harriman, K.; Tehranchi, B.

    1993-01-01

    The objectives of this project are as follows: provide hardware and software that will perform simple, real-time, high resolution (single-byte) measurement of the error burst and good data gap statistics seen by a photoCD player read channel when recorded CD write-once discs of variable quality (i.e., condition) are being read; extend the above system to enable measurement of the hard decision (i.e., 1-bit error flags) and soft decision (i.e., 2-bit error flags) decoding information that is produced/used by the Cross Interleaved - Reed - Solomon - Code (CIRC) block decoder employed in the photoCD player read channel; construct a model that uses data obtained via the systems described above to produce meaningful estimates of output error rates (due to both uncorrected ECC words and misdecoded ECC words) when a CD disc having specific (measured) error statistics is read (completion date to be determined); and check the hypothesis that current adaptive CIRC block decoders are optimized for pressed (DAD/ROM) CD discs. If warranted, do a conceptual design of an adaptive CIRC decoder that is optimized for write-once CD discs.

  7. Measurement errors in the assessment of exposure to solar ultraviolet radiation and its impact on risk estimates in epidemiological studies.

    Science.gov (United States)

    Dadvand, Payam; Basagaña, Xavier; Barrera-Gómez, Jose; Diffey, Brian; Nieuwenhuijsen, Mark

    2011-07-01

    To date, many studies addressing long-term effects of ultraviolet radiation (UVR) exposure on human health have relied on a range of surrogates such as the latitude of the city of residence, ambient UVR levels, or time spent outdoors to estimate personal UVR exposure. This study aimed to differentiate the contributions of personal behaviour and ambient UVR levels on facial UVR exposure and to evaluate the impact of using UVR exposure surrogates on detecting exposure-outcome associations. Data on time-activity, holiday behaviour, and ambient UVR levels were obtained for adult (aged 25-55 years old) indoor workers in six European cities: Athens (37°N), Grenoble (45°N), Milan (45°N), Prague (50°N), Oxford (52°N), and Helsinki (60°N). Annual UVR facial exposure levels were simulated for 10,000 subjects for each city, using a behavioural UVR exposure model. Within-city variations of facial UVR exposure were three times larger than the variation between cities, mainly because of time-activity patterns. In univariate models, ambient UVR levels, latitude and time spent outdoors, each accounted for less than one fourth of the variation in facial exposure levels. Use of these surrogates to assess long-term exposure to UVR resulted in requiring more than four times more participants to achieve similar statistical power to the study that applied simulated facial exposure. Our results emphasise the importance of integrating both personal behaviour and ambient UVR levels/latitude in exposure assessment methodologies.

  8. Human errors related to maintenance and modifications

    International Nuclear Information System (INIS)

    Laakso, K.; Pyy, P.; Reiman, L.

    1998-01-01

    The focus in human reliability analysis (HRA) relating to nuclear power plants has traditionally been on human performance in disturbance conditions. On the other hand, some studies and incidents have shown that also maintenance errors, which have taken place earlier in plant history, may have an impact on the severity of a disturbance, e.g. if they disable safety related equipment. Especially common cause and other dependent failures of safety systems may significantly contribute to the core damage risk. The first aim of the study was to identify and give examples of multiple human errors which have penetrated the various error detection and inspection processes of plant safety barriers. Another objective was to generate numerical safety indicators to describe and forecast the effectiveness of maintenance. A more general objective was to identify needs for further development of maintenance quality and planning. In the first phase of this operational experience feedback analysis, human errors recognisable in connection with maintenance were looked for by reviewing about 4400 failure and repair reports and some special reports which cover two nuclear power plant units on the same site during 1992-94. A special effort was made to study dependent human errors since they are generally the most serious ones. An in-depth root cause analysis was made for 14 dependent errors by interviewing plant maintenance foremen and by thoroughly analysing the errors. A more simple treatment was given to maintenance-related single errors. The results were shown as a distribution of errors among operating states i.a. as regards the following matters: in what operational state the errors were committed and detected; in what operational and working condition the errors were detected, and what component and error type they were related to. These results were presented separately for single and dependent maintenance-related errors. As regards dependent errors, observations were also made

  9. Errors in Neonatology

    Directory of Open Access Journals (Sweden)

    Antonio Boldrini

    2013-06-01

    Full Text Available Introduction: Danger and errors are inherent in human activities. In medical practice errors can lean to adverse events for patients. Mass media echo the whole scenario. Methods: We reviewed recent published papers in PubMed database to focus on the evidence and management of errors in medical practice in general and in Neonatology in particular. We compared the results of the literature with our specific experience in Nina Simulation Centre (Pisa, Italy. Results: In Neonatology the main error domains are: medication and total parenteral nutrition, resuscitation and respiratory care, invasive procedures, nosocomial infections, patient identification, diagnostics. Risk factors include patients’ size, prematurity, vulnerability and underlying disease conditions but also multidisciplinary teams, working conditions providing fatigue, a large variety of treatment and investigative modalities needed. Discussion and Conclusions: In our opinion, it is hardly possible to change the human beings but it is likely possible to change the conditions under they work. Voluntary errors report systems can help in preventing adverse events. Education and re-training by means of simulation can be an effective strategy too. In Pisa (Italy Nina (ceNtro di FormazIone e SimulazioNe NeonAtale is a simulation center that offers the possibility of a continuous retraining for technical and non-technical skills to optimize neonatological care strategies. Furthermore, we have been working on a novel skill trainer for mechanical ventilation (MEchatronic REspiratory System SImulator for Neonatal Applications, MERESSINA. Finally, in our opinion national health policy indirectly influences risk for errors. Proceedings of the 9th International Workshop on Neonatology · Cagliari (Italy · October 23rd-26th, 2013 · Learned lessons, changing practice and cutting-edge research

  10. LIBERTARISMO & ERROR CATEGORIAL

    Directory of Open Access Journals (Sweden)

    Carlos G. Patarroyo G.

    2009-01-01

    Full Text Available En este artículo se ofrece una defensa del libertarismo frente a dos acusaciones según las cuales éste comete un error categorial. Para ello, se utiliza la filosofía de Gilbert Ryle como herramienta para explicar las razones que fundamentan estas acusaciones y para mostrar por qué, pese a que ciertas versiones del libertarismo que acuden a la causalidad de agentes o al dualismo cartesiano cometen estos errores, un libertarismo que busque en el indeterminismo fisicalista la base de la posibilidad de la libertad humana no necesariamente puede ser acusado de incurrir en ellos.

  11. Libertarismo & Error Categorial

    OpenAIRE

    PATARROYO G, CARLOS G

    2009-01-01

    En este artículo se ofrece una defensa del libertarismo frente a dos acusaciones según las cuales éste comete un error categorial. Para ello, se utiliza la filosofía de Gilbert Ryle como herramienta para explicar las razones que fundamentan estas acusaciones y para mostrar por qué, pese a que ciertas versiones del libertarismo que acuden a la causalidad de agentes o al dualismo cartesiano cometen estos errores, un libertarismo que busque en el indeterminismo fisicalista la base de la posibili...

  12. Error Free Software

    Science.gov (United States)

    1985-01-01

    A mathematical theory for development of "higher order" software to catch computer mistakes resulted from a Johnson Space Center contract for Apollo spacecraft navigation. Two women who were involved in the project formed Higher Order Software, Inc. to develop and market the system of error analysis and correction. They designed software which is logically error-free, which, in one instance, was found to increase productivity by 600%. USE.IT defines its objectives using AXES -- a user can write in English and the system converts to computer languages. It is employed by several large corporations.

  13. Optimization of DSC MRI Echo Times for CBV Measurements Using Error Analysis in a Pilot Study of High-Grade Gliomas.

    Science.gov (United States)

    Bell, L C; Does, M D; Stokes, A M; Baxter, L C; Schmainda, K M; Dueck, A C; Quarles, C C

    2017-09-01

    The optimal TE must be calculated to minimize the variance in CBV measurements made with DSC MR imaging. Simulations can be used to determine the influence of the TE on CBV, but they may not adequately recapitulate the in vivo heterogeneity of precontrast T2*, contrast agent kinetics, and the biophysical basis of contrast agent-induced T2* changes. The purpose of this study was to combine quantitative multiecho DSC MRI T2* time curves with error analysis in order to compute the optimal TE for a traditional single-echo acquisition. Eleven subjects with high-grade gliomas were scanned at 3T with a dual-echo DSC MR imaging sequence to quantify contrast agent-induced T2* changes in this retrospective study. Optimized TEs were calculated with propagation of error analysis for high-grade glial tumors, normal-appearing white matter, and arterial input function estimation. The optimal TE is a weighted average of the T2* values that occur as a contrast agent bolus transverses a voxel. The mean optimal TEs were 30.0 ± 7.4 ms for high-grade glial tumors, 36.3 ± 4.6 ms for normal-appearing white matter, and 11.8 ± 1.4 ms for arterial input function estimation (repeated-measures ANOVA, P optimal TE values for high-grade gliomas, and mean values of all 3 ROIs were statistically significant. The optimal TE for the arterial input function estimation is much shorter; this finding implies that quantitative DSC MR imaging acquisitions would benefit from multiecho acquisitions. In the case of a single-echo acquisition, the optimal TE prescribed should be 30-35 ms (without a preload) and 20-30 ms (with a standard full-dose preload). © 2017 by American Journal of Neuroradiology.

  14. Modelling and mitigation of soft-errors in CMOS processors

    NARCIS (Netherlands)

    Rohani, A.

    2014-01-01

    The topic of this thesis is about soft-errors in digital systems. Different aspects of soft-errors have been addressed here, including an accurate simulation model to emulate soft-errors in a gate-level net list, a simulation framework to study the impact of soft-errors in a VHDL design and an

  15. Error Analysis of Determining Airplane Location by Global Positioning System

    OpenAIRE

    Hajiyev, Chingiz; Burat, Alper

    1999-01-01

    This paper studies the error analysis of determining airplane location by global positioning system (GPS) using statistical testing method. The Newton Rhapson method positions the airplane at the intersection point of four spheres. Absolute errors, relative errors and standard deviation have been calculated The results show that the positioning error of the airplane varies with the coordinates of GPS satellite and the airplane.

  16. Awareness of technology-induced errors and processes for identifying and preventing such errors.

    Science.gov (United States)

    Bellwood, Paule; Borycki, Elizabeth M; Kushniruk, Andre W

    2015-01-01

    There is a need to determine if organizations working with health information technology are aware of technology-induced errors and how they are addressing and preventing them. The purpose of this study was to: a) determine the degree of technology-induced error awareness in various Canadian healthcare organizations, and b) identify those processes and procedures that are currently in place to help address, manage, and prevent technology-induced errors. We identified a lack of technology-induced error awareness among participants. Participants identified there was a lack of well-defined procedures in place for reporting technology-induced errors, addressing them when they arise, and preventing them.

  17. A study of respiration-correlated cone-beam CT scans to correct target positioning errors in radiotherapy of thoracic cancer

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, J. P.; McNamara, J.; Yorke, E.; Pham, H.; Rimner, A.; Rosenzweig, K. E.; Mageras, G. S. [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York 10065 (United States); Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York 10065 (United States); Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York 10065 (United States)

    2012-10-15

    Purpose: There is increasingly widespread usage of cone-beam CT (CBCT) for guiding radiation treatment in advanced-stage lung tumors, but difficulties associated with daily CBCT in conventionally fractionated treatments include imaging dose to the patient, increased workload and longer treatment times. Respiration-correlated cone-beam CT (RC-CBCT) can improve localization accuracy in mobile lung tumors, but further increases the time and workload for conventionally fractionated treatments. This study investigates whether RC-CBCT-guided correction of systematic tumor deviations in standard fractionated lung tumor radiation treatments is more effective than 2D image-based correction of skeletal deviations alone. A second study goal compares respiration-correlated vs respiration-averaged images for determining tumor deviations. Methods: Eleven stage II-IV nonsmall cell lung cancer patients are enrolled in an IRB-approved prospective off-line protocol using RC-CBCT guidance to correct for systematic errors in GTV position. Patients receive a respiration-correlated planning CT (RCCT) at simulation, daily kilovoltage RC-CBCT scans during the first week of treatment and weekly scans thereafter. Four types of correction methods are compared: (1) systematic error in gross tumor volume (GTV) position, (2) systematic error in skeletal anatomy, (3) daily skeletal corrections, and (4) weekly skeletal corrections. The comparison is in terms of weighted average of the residual GTV deviations measured from the RC-CBCT scans and representing the estimated residual deviation over the treatment course. In the second study goal, GTV deviations computed from matching RCCT and RC-CBCT are compared to deviations computed from matching respiration-averaged images consisting of a CBCT reconstructed using all projections and an average-intensity-projection CT computed from the RCCT. Results: Of the eleven patients in the GTV-based systematic correction protocol, two required no correction

  18. A study of respiration-correlated cone-beam CT scans to correct target positioning errors in radiotherapy of thoracic cancer

    International Nuclear Information System (INIS)

    Santoro, J. P.; McNamara, J.; Yorke, E.; Pham, H.; Rimner, A.; Rosenzweig, K. E.; Mageras, G. S.

    2012-01-01

    Purpose: There is increasingly widespread usage of cone-beam CT (CBCT) for guiding radiation treatment in advanced-stage lung tumors, but difficulties associated with daily CBCT in conventionally fractionated treatments include imaging dose to the patient, increased workload and longer treatment times. Respiration-correlated cone-beam CT (RC-CBCT) can improve localization accuracy in mobile lung tumors, but further increases the time and workload for conventionally fractionated treatments. This study investigates whether RC-CBCT-guided correction of systematic tumor deviations in standard fractionated lung tumor radiation treatments is more effective than 2D image-based correction of skeletal deviations alone. A second study goal compares respiration-correlated vs respiration-averaged images for determining tumor deviations. Methods: Eleven stage II–IV nonsmall cell lung cancer patients are enrolled in an IRB-approved prospective off-line protocol using RC-CBCT guidance to correct for systematic errors in GTV position. Patients receive a respiration-correlated planning CT (RCCT) at simulation, daily kilovoltage RC-CBCT scans during the first week of treatment and weekly scans thereafter. Four types of correction methods are compared: (1) systematic error in gross tumor volume (GTV) position, (2) systematic error in skeletal anatomy, (3) daily skeletal corrections, and (4) weekly skeletal corrections. The comparison is in terms of weighted average of the residual GTV deviations measured from the RC-CBCT scans and representing the estimated residual deviation over the treatment course. In the second study goal, GTV deviations computed from matching RCCT and RC-CBCT are compared to deviations computed from matching respiration-averaged images consisting of a CBCT reconstructed using all projections and an average-intensity-projection CT computed from the RCCT. Results: Of the eleven patients in the GTV-based systematic correction protocol, two required no correction

  19. Preventing Medication Error Based on Knowledge Management Against Adverse Event

    OpenAIRE

    Hastuti, Apriyani Puji; Nursalam, Nursalam; Triharini, Mira

    2017-01-01

    Introductions: Medication error is one of many types of errors that could decrease the quality and safety of healthcare. Increasing number of adverse events (AE) reflects the number of medication errors. This study aimed to develop a model of medication error prevention based on knowledge management. This model is expected to improve knowledge and skill of nurses to prevent medication error which is characterized by the decrease of adverse events (AE). Methods: This study consisted of two sta...

  20. Error Correcting Codes

    Indian Academy of Sciences (India)

    Science and Automation at ... the Reed-Solomon code contained 223 bytes of data, (a byte ... then you have a data storage system with error correction, that ..... practical codes, storing such a table is infeasible, as it is generally too large.

  1. Error Correcting Codes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 3. Error Correcting Codes - Reed Solomon Codes. Priti Shankar. Series Article Volume 2 Issue 3 March ... Author Affiliations. Priti Shankar1. Department of Computer Science and Automation, Indian Institute of Science, Bangalore 560 012, India ...

  2. PREVALENCE OF REFRACTIVE ERROR, STRABISMUS AND AMBLYOPIA AMONG CHILDREN WITH NORMAL DEVELOPMENT OR GLOBAL DEVELOPMENTAL DELAY/INTELLECTUAL DISABILITY ATTENDING OPHTHALMOLOGY OPD AT KLES HOSPITAL, BELAGAVI- A RETROSPECTIVE STUDY

    Directory of Open Access Journals (Sweden)

    Smitha K. S

    2017-04-01

    Full Text Available BACKGROUND Global developmental delay/intellectual disability are on a rise in children in the present time. Ocular and visual anomalies are frequently associated with it of which refractive errors are the most frequent. This if goes unnoticed leads to strabismus and amblyopia. MATERIALS AND METHODS This study aims to assess the prevalence of refractive error, strabismus and amblyopia among children with normal development or global developmental delay/intellectual disability attending ophthalmology OPD at KLES Hospital, Belagavi. Case records of all 200 new patients less than or equal to 12 years of age group who attended KLES, Dr. Prabhakar Kore Hospital between January 2015 and December 2015 were retrospectively reviewed. RESULTS The male:female ratio was 1.22:1. Out of the total evaluated 200 cases, 130 cases were with normal development and 70 with GDD/ID. Refractive errors were 85%, whereas the cases of amblyopia was 45.50% and strabismus 39.50%. Amblyopia with refractive error having GDD/ID was stastically significant as compared to amblyopia with refractive error having normal development (p=0.001. CONCLUSION Refractive error was the most common ocular disorder seen. Refractive error with amblyopia is more in children with GDD/ID as compared to normal children. Owing to the high percentage of visual anomalies, ophthalmological referral becomes essential in children with developmental anomalies.

  3. Challenge and Error: Critical Events and Attention-Related Errors

    Science.gov (United States)

    Cheyne, James Allan; Carriere, Jonathan S. A.; Solman, Grayden J. F.; Smilek, Daniel

    2011-01-01

    Attention lapses resulting from reactivity to task challenges and their consequences constitute a pervasive factor affecting everyday performance errors and accidents. A bidirectional model of attention lapses (error [image omitted] attention-lapse: Cheyne, Solman, Carriere, & Smilek, 2009) argues that errors beget errors by generating attention…

  4. Team errors: definition and taxonomy

    International Nuclear Information System (INIS)

    Sasou, Kunihide; Reason, James

    1999-01-01

    In error analysis or error management, the focus is usually upon individuals who have made errors. In large complex systems, however, most people work in teams or groups. Considering this working environment, insufficient emphasis has been given to 'team errors'. This paper discusses the definition of team errors and its taxonomy. These notions are also applied to events that have occurred in the nuclear power industry, aviation industry and shipping industry. The paper also discusses the relations between team errors and Performance Shaping Factors (PSFs). As a result, the proposed definition and taxonomy are found to be useful in categorizing team errors. The analysis also reveals that deficiencies in communication, resource/task management, excessive authority gradient, excessive professional courtesy will cause team errors. Handling human errors as team errors provides an opportunity to reduce human errors

  5. Comparing classifiers for pronunciation error detection

    NARCIS (Netherlands)

    Strik, H.; Truong, K.; Wet, F. de; Cucchiarini, C.

    2007-01-01

    Providing feedback on pronunciation errors in computer assisted language learning systems requires that pronunciation errors be detected automatically. In the present study we compare four types of classifiers that can be used for this purpose: two acoustic-phonetic classifiers (one of which employs

  6. Comparison of Prediction-Error-Modelling Criteria

    DEFF Research Database (Denmark)

    Jørgensen, John Bagterp; Jørgensen, Sten Bay

    2007-01-01

    Single and multi-step prediction-error-methods based on the maximum likelihood and least squares criteria are compared. The prediction-error methods studied are based on predictions using the Kalman filter and Kalman predictors for a linear discrete-time stochastic state space model, which is a r...

  7. Error and uncertainty in scientific practice

    NARCIS (Netherlands)

    Boumans, M.; Hon, G.; Petersen, A.C.

    2014-01-01

    Assessment of error and uncertainty is a vital component of both natural and social science. Empirical research involves dealing with all kinds of errors and uncertainties, yet there is significant variance in how such results are dealt with. Contributors to this volume present case studies of

  8. Error Detection and Error Classification: Failure Awareness in Data Transfer Scheduling

    Energy Technology Data Exchange (ETDEWEB)

    Louisiana State University; Balman, Mehmet; Kosar, Tevfik

    2010-10-27

    Data transfer in distributed environment is prone to frequent failures resulting from back-end system level problems, like connectivity failure which is technically untraceable by users. Error messages are not logged efficiently, and sometimes are not relevant/useful from users point-of-view. Our study explores the possibility of an efficient error detection and reporting system for such environments. Prior knowledge about the environment and awareness of the actual reason behind a failure would enable higher level planners to make better and accurate decisions. It is necessary to have well defined error detection and error reporting methods to increase the usability and serviceability of existing data transfer protocols and data management systems. We investigate the applicability of early error detection and error classification techniques and propose an error reporting framework and a failure-aware data transfer life cycle to improve arrangement of data transfer operations and to enhance decision making of data transfer schedulers.

  9. Imagery of Errors in Typing

    Science.gov (United States)

    Rieger, Martina; Martinez, Fanny; Wenke, Dorit

    2011-01-01

    Using a typing task we investigated whether insufficient imagination of errors and error corrections is related to duration differences between execution and imagination. In Experiment 1 spontaneous error imagination was investigated, whereas in Experiment 2 participants were specifically instructed to imagine errors. Further, in Experiment 2 we…

  10. SU-D-201-01: A Multi-Institutional Study Quantifying the Impact of Simulated Linear Accelerator VMAT Errors for Nasopharynx

    International Nuclear Information System (INIS)

    Pogson, E; Hansen, C; Blake, S; Thwaites, D; Arumugam, S; Juresic, J; Ochoa, C; Yakobi, J; Haman, A; Trtovac, A; Holloway, L

    2016-01-01

    Purpose: To quantify the impact of differing magnitudes of simulated linear accelerator errors on the dose to the target volume and organs at risk for nasopharynx VMAT. Methods: Ten nasopharynx cancer patients were retrospectively replanned twice with one full arc VMAT by two institutions. Treatment uncertainties (gantry angle and collimator in degrees, MLC field size and MLC shifts in mm) were introduced into these plans at increments of 5,2,1,−1,−2 and −5. This was completed using an in-house Python script within Pinnacle3 and analysed using 3DVH and MatLab. The mean and maximum dose were calculated for the Planning Target Volume (PTV1), parotids, brainstem, and spinal cord and then compared to the original baseline plan. The D1cc was also calculated for the spinal cord and brainstem. Patient average results were compared across institutions. Results: Introduced gantry angle errors had the smallest effect of dose, no tolerances were exceeded for one institution, and the second institutions VMAT plans were only exceeded for gantry angle of ±5° affecting different sided parotids by 14–18%. PTV1, brainstem and spinal cord tolerances were exceeded for collimator angles of ±5 degrees, MLC shifts and MLC field sizes of ±1 and beyond, at the first institution. At the second institution, sensitivity to errors was marginally higher for some errors including the collimator error producing doses exceeding tolerances above ±2 degrees, and marginally lower with tolerances exceeded above MLC shifts of ±2. The largest differences occur with MLC field sizes, with both institutions reporting exceeded tolerances, for all introduced errors (±1 and beyond). Conclusion: The plan robustness for VMAT nasopharynx plans has been demonstrated. Gantry errors have the least impact on patient doses, however MLC field sizes exceed tolerances even with relatively low introduced errors and also produce the largest errors. This was consistent across both departments. The authors

  11. SU-D-201-01: A Multi-Institutional Study Quantifying the Impact of Simulated Linear Accelerator VMAT Errors for Nasopharynx

    Energy Technology Data Exchange (ETDEWEB)

    Pogson, E [Institute of Medical Physics, The University of Sydney, Sydney, NSW (Australia); Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW (Australia); Ingham Institute for Applied Medical Research, Sydney, NSW (Australia); Hansen, C [Laboratory of Radiation Physics, Odense University Hospital, Odense (Denmark); Institute of Clinical Research, University of Southern Denmark, Odense (Denmark); Blake, S; Thwaites, D [Institute of Medical Physics, The University of Sydney, Sydney, NSW (Australia); Arumugam, S; Juresic, J; Ochoa, C; Yakobi, J; Haman, A; Trtovac, A [Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW (Australia); Holloway, L [Institute of Medical Physics, The University of Sydney, Sydney, NSW (Australia); Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW (Australia); Ingham Institute for Applied Medical Research, Sydney, NSW (Australia); South Western Sydney Clinical School, University of New South Wales, Sydney, NSW (Australia); University of Wollongong, Wollongong, NSW (Australia)

    2016-06-15

    Purpose: To quantify the impact of differing magnitudes of simulated linear accelerator errors on the dose to the target volume and organs at risk for nasopharynx VMAT. Methods: Ten nasopharynx cancer patients were retrospectively replanned twice with one full arc VMAT by two institutions. Treatment uncertainties (gantry angle and collimator in degrees, MLC field size and MLC shifts in mm) were introduced into these plans at increments of 5,2,1,−1,−2 and −5. This was completed using an in-house Python script within Pinnacle3 and analysed using 3DVH and MatLab. The mean and maximum dose were calculated for the Planning Target Volume (PTV1), parotids, brainstem, and spinal cord and then compared to the original baseline plan. The D1cc was also calculated for the spinal cord and brainstem. Patient average results were compared across institutions. Results: Introduced gantry angle errors had the smallest effect of dose, no tolerances were exceeded for one institution, and the second institutions VMAT plans were only exceeded for gantry angle of ±5° affecting different sided parotids by 14–18%. PTV1, brainstem and spinal cord tolerances were exceeded for collimator angles of ±5 degrees, MLC shifts and MLC field sizes of ±1 and beyond, at the first institution. At the second institution, sensitivity to errors was marginally higher for some errors including the collimator error producing doses exceeding tolerances above ±2 degrees, and marginally lower with tolerances exceeded above MLC shifts of ±2. The largest differences occur with MLC field sizes, with both institutions reporting exceeded tolerances, for all introduced errors (±1 and beyond). Conclusion: The plan robustness for VMAT nasopharynx plans has been demonstrated. Gantry errors have the least impact on patient doses, however MLC field sizes exceed tolerances even with relatively low introduced errors and also produce the largest errors. This was consistent across both departments. The authors

  12. The Errors of Our Ways: Understanding Error Representations in Cerebellar-Dependent Motor Learning.

    Science.gov (United States)

    Popa, Laurentiu S; Streng, Martha L; Hewitt, Angela L; Ebner, Timothy J

    2016-04-01

    The cerebellum is essential for error-driven motor learning and is strongly implicated in detecting and correcting for motor errors. Therefore, elucidating how motor errors are represented in the cerebellum is essential in understanding cerebellar function, in general, and its role in motor learning, in particular. This review examines how motor errors are encoded in the cerebellar cortex in the context of a forward internal model that generates predictions about the upcoming movement and drives learning and adaptation. In this framework, sensory prediction errors, defined as the discrepancy between the predicted consequences of motor commands and the sensory feedback, are crucial for both on-line movement control and motor learning. While many studies support the dominant view that motor errors are encoded in the complex spike discharge of Purkinje cells, others have failed to relate complex spike activity with errors. Given these limitations, we review recent findings in the monkey showing that complex spike modulation is not necessarily required for motor learning or for simple spike adaptation. Also, new results demonstrate that the simple spike discharge provides continuous error signals that both lead and lag the actual movements in time, suggesting errors are encoded as both an internal prediction of motor commands and the actual sensory feedback. These dual error representations have opposing effects on simple spike discharge, consistent with the signals needed to generate sensory prediction errors used to update a forward internal model.

  13. MAX-DOAS measurements of HONO slant column densities during the MAD-CAT campaign: inter-comparison, sensitivity studies on spectral analysis settings, and error budget

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2017-10-01

    about half of the systematic difference between the real measurements.The differences of HONO delta SCDs retrieved in the selected three spectral ranges 335–361, 335–373 and 335–390 nm are considerable (up to 0.57  ×  1015 molecules cm−2 for both real measurements and synthetic spectra. We performed sensitivity studies to quantify the dominant systematic error sources and to find a recommended DOAS setting in the three spectral ranges. The results show that water vapour absorption, temperature and wavelength dependence of O4 absorption, temperature dependence of Ring spectrum, and polynomial and intensity offset correction all together dominate the systematic errors. We recommend a fit range of 335–373 nm for HONO retrievals. In such fit range the overall systematic uncertainty is about 0.87  ×  1015 molecules cm−2, much smaller than those in the other two ranges. The typical random uncertainty is estimated to be about 0.16  ×  1015 molecules cm−2, which is only 25 % of the total systematic uncertainty for most of the instruments in the MAD-CAT campaign. In summary for most of the MAX-DOAS instruments for elevation angle below 5°, half daytime measurements (usually in the morning of HONO delta SCD can be over the detection limit of 0.2  ×  1015 molecules cm−2 with an uncertainty of  ∼  0.9  ×  1015 molecules cm−2.

  14. The socio-economic patterning of survey participation and non-response error in a multilevel study of food purchasing behaviour: area- and individual-level characteristics.

    Science.gov (United States)

    Turrell, Gavin; Patterson, Carla; Oldenburg, Brian; Gould, Trish; Roy, Marie-Andree

    2003-04-01

    To undertake an assessment of survey participation and non-response error in a population-based study that examined the relationship between socio-economic position and food purchasing behaviour. The study was conducted in Brisbane City (Australia) in 2000. The sample was selected using a stratified two-stage cluster design. Respondents were recruited using a range of strategies that attempted to maximise the involvement of persons from disadvantaged backgrounds: respondents were contacted by personal visit and data were collected using home-based face-to-face interviews; multiple call-backs on different days and at different times were used; and a financial gratuity was provided. Non-institutionalised residents of private dwellings located in 50 small areas that differed in their socio-economic characteristics. Rates of survey participation - measured by non-contacts, exclusions, dropped cases, response rates and completions - were similar across areas, suggesting that residents of socio-economically advantaged and disadvantaged areas were equally likely to be recruited. Individual-level analysis, however, showed that respondents and non-respondents differed significantly in their sociodemographic and food purchasing characteristics: non-respondents were older, less educated and exhibited different purchasing behaviours. Misclassification bias probably accounted for the inconsistent pattern of association between the area- and individual-level results. Estimates of bias due to non-response indicated that although respondents and non-respondents were qualitatively different, the magnitude of error associated with this differential was minimal. Socio-economic position measured at the individual level is a strong and consistent predictor of survey non-participation. Future studies that set out to examine the relationship between socio-economic position and diet need to adopt sampling strategies and data collection methods that maximise the likelihood of recruiting

  15. Correction of refractive errors

    Directory of Open Access Journals (Sweden)

    Vladimir Pfeifer

    2005-10-01

    Full Text Available Background: Spectacles and contact lenses are the most frequently used, the safest and the cheapest way to correct refractive errors. The development of keratorefractive surgery has brought new opportunities for correction of refractive errors in patients who have the need to be less dependent of spectacles or contact lenses. Until recently, RK was the most commonly performed refractive procedure for nearsighted patients.Conclusions: The introduction of excimer laser in refractive surgery has given the new opportunities of remodelling the cornea. The laser energy can be delivered on the stromal surface like in PRK or deeper on the corneal stroma by means of lamellar surgery. In LASIK flap is created with microkeratome in LASEK with ethanol and in epi-LASIK the ultra thin flap is created mechanically.

  16. Error-Free Software

    Science.gov (United States)

    1989-01-01

    001 is an integrated tool suited for automatically developing ultra reliable models, simulations and software systems. Developed and marketed by Hamilton Technologies, Inc. (HTI), it has been applied in engineering, manufacturing, banking and software tools development. The software provides the ability to simplify the complex. A system developed with 001 can be a prototype or fully developed with production quality code. It is free of interface errors, consistent, logically complete and has no data or control flow errors. Systems can be designed, developed and maintained with maximum productivity. Margaret Hamilton, President of Hamilton Technologies, also directed the research and development of USE.IT, an earlier product which was the first computer aided software engineering product in the industry to concentrate on automatically supporting the development of an ultrareliable system throughout its life cycle. Both products originated in NASA technology developed under a Johnson Space Center contract.

  17. Minimum Tracking Error Volatility

    OpenAIRE

    Luca RICCETTI

    2010-01-01

    Investors assign part of their funds to asset managers that are given the task of beating a benchmark. The risk management department usually imposes a maximum value of the tracking error volatility (TEV) in order to keep the risk of the portfolio near to that of the selected benchmark. However, risk management does not establish a rule on TEV which enables us to understand whether the asset manager is really active or not and, in practice, asset managers sometimes follow passively the corres...

  18. Satellite Photometric Error Determination

    Science.gov (United States)

    2015-10-18

    Satellite Photometric Error Determination Tamara E. Payne, Philip J. Castro, Stephen A. Gregory Applied Optimization 714 East Monument Ave, Suite...advocate the adoption of new techniques based on in-frame photometric calibrations enabled by newly available all-sky star catalogs that contain highly...filter systems will likely be supplanted by the Sloan based filter systems. The Johnson photometric system is a set of filters in the optical

  19. Video Error Correction Using Steganography

    Science.gov (United States)

    Robie, David L.; Mersereau, Russell M.

    2002-12-01

    The transmission of any data is always subject to corruption due to errors, but video transmission, because of its real time nature must deal with these errors without retransmission of the corrupted data. The error can be handled using forward error correction in the encoder or error concealment techniques in the decoder. This MPEG-2 compliant codec uses data hiding to transmit error correction information and several error concealment techniques in the decoder. The decoder resynchronizes more quickly with fewer errors than traditional resynchronization techniques. It also allows for perfect recovery of differentially encoded DCT-DC components and motion vectors. This provides for a much higher quality picture in an error-prone environment while creating an almost imperceptible degradation of the picture in an error-free environment.

  20. Video Error Correction Using Steganography

    Directory of Open Access Journals (Sweden)

    Robie David L

    2002-01-01

    Full Text Available The transmission of any data is always subject to corruption due to errors, but video transmission, because of its real time nature must deal with these errors without retransmission of the corrupted data. The error can be handled using forward error correction in the encoder or error concealment techniques in the decoder. This MPEG-2 compliant codec uses data hiding to transmit error correction information and several error concealment techniques in the decoder. The decoder resynchronizes more quickly with fewer errors than traditional resynchronization techniques. It also allows for perfect recovery of differentially encoded DCT-DC components and motion vectors. This provides for a much higher quality picture in an error-prone environment while creating an almost imperceptible degradation of the picture in an error-free environment.

  1. Comparing Absolute Error with Squared Error for Evaluating Empirical Models of Continuous Variables: Compositions, Implications, and Consequences

    Science.gov (United States)

    Gao, J.

    2014-12-01

    Reducing modeling error is often a major concern of empirical geophysical models. However, modeling errors can be defined in different ways: When the response variable is continuous, the most commonly used metrics are squared (SQ) and absolute (ABS) errors. For most applications, ABS error is the more natural, but SQ error is mathematically more tractable, so is often used as a substitute with little scientific justification. Existing literature has not thoroughly investigated the implications of using SQ error in place of ABS error, especially not geospatially. This study compares the two metrics through the lens of bias-variance decomposition (BVD). BVD breaks down the expected modeling error of each model evaluation point into bias (systematic error), variance (model sensitivity), and noise (observation instability). It offers a way to probe the composition of various error metrics. I analytically derived the BVD of ABS error and compared it with the well-known SQ error BVD, and found that not only the two metrics measure the characteristics of the probability distributions of modeling errors differently, but also the effects of these characteristics on the overall expected error are different. Most notably, under SQ error all bias, variance, and noise increase expected error, while under ABS error certain parts of the error components reduce expected error. Since manipulating these subtractive terms is a legitimate way to reduce expected modeling error, SQ error can never capture the complete story embedded in ABS error. I then empirically compared the two metrics with a supervised remote sensing model for mapping surface imperviousness. Pair-wise spatially-explicit comparison for each error component showed that SQ error overstates all error components in comparison to ABS error, especially variance-related terms. Hence, substituting ABS error with SQ error makes model performance appear worse than it actually is, and the analyst would more likely accept a

  2. Use of a urinary sugars biomarker to assess measurement error in self-reported sugars intake in the Nutrition and Physical Activity Assessment Study (NPAAS)

    Science.gov (United States)

    Tasevska, Natasha; Midthune, Douglas; Tinker, Lesley F.; Potischman, Nancy; Lampe, Johanna W.; Neuhouser, Marian L.; Beasley, Jeannette M.; Van Horn, Linda; Prentice, Ross L.; Kipnis, Victor

    2014-01-01

    Background Measurement error (ME) in self-reported sugars intake may be obscuring the association between sugars and cancer risk in nutritional epidemiologic studies. Methods We used 24-hour urinary sucrose and fructose as a predictive biomarker for total sugars, to assess ME in self-reported sugars intake. The Nutrition and Physical Activity Assessment Study (NPAAS) is a biomarker study within the Women’s Health Initiative (WHI) Observational Study, that includes 450 post-menopausal women aged 60–91. Food Frequency Questionnaires (FFQ), 4-day food records (4DFR) and three 24-h dietary recalls (24HRs) were collected along with sugars and energy dietary biomarkers. Results Using the biomarker, we found self-reported sugars to be substantially and roughly equally misreported across the FFQ, 4DFR and 24HR. All instruments were associated with considerable intake- and person-specific bias. Three 24HRs would provide the least attenuated risk estimate for sugars (attenuation factor, AF=0.57), followed by FFQ (AF=0.48), and 4DFR (AF=0.32), in studies of energy-adjusted sugars and disease risk. In calibration models, self-reports explained little variation in true intake (5–6% for absolute sugars; 7–18% for sugars density). Adding participants’ characteristics somewhat improved the percentage variation explained (16–18% for absolute sugars; 29–40% for sugars density). Conclusions None of the self-report instruments provided a good estimate of sugars intake, although overall 24HRs seemed to perform the best. Impact Assuming the calibrated sugars biomarker is unbiased, this analysis suggests that, measuring the biomarker in a subsample of the study population for calibration purposes may be necessary for obtaining unbiased risk estimates in cancer association studies. PMID:25234237

  3. Evaluation and comparison of the processing methods of airborne gravimetry concerning the errors effects on downward continuation results: Case studies in Louisiana (USA) and the Tibetan Plateau (China)

    DEFF Research Database (Denmark)

    Zhao, Qilong; Strykowski, Gabriel; Li, Jiancheng

    2017-01-01

    and the most extreme area of the world for this type of survey is the Tibetan Plateau. Since there are no high-accuracy surface gravity data available for this area, the above error minimization method involving the external gravity data cannot be used. We propose a semi-parametric downward continuation method...... in combination with regularization to suppress the systematic error effect and the random error effect in the Tibetan Plateau; i.e., without the use of the external high-accuracy gravity data. We use a Louisiana airborne gravity dataset from the USA National Oceanic and Atmospheric Administration (NOAA......) to demonstrate that the new method works effectively. Furthermore, and for the Tibetan Plateau we show that the numerical experiment is also successfully conducted using the synthetic Earth Gravitational Model 2008 (EGM08)-derived gravity data contaminated with the synthetic errors. The estimated systematic...

  4. Error-related brain activity and error awareness in an error classification paradigm.

    Science.gov (United States)

    Di Gregorio, Francesco; Steinhauser, Marco; Maier, Martin E

    2016-10-01

    Error-related brain activity has been linked to error detection enabling adaptive behavioral adjustments. However, it is still unclear which role error awareness plays in this process. Here, we show that the error-related negativity (Ne/ERN), an event-related potential reflecting early error monitoring, is dissociable from the degree of error awareness. Participants responded to a target while ignoring two different incongruent distractors. After responding, they indicated whether they had committed an error, and if so, whether they had responded to one or to the other distractor. This error classification paradigm allowed distinguishing partially aware errors, (i.e., errors that were noticed but misclassified) and fully aware errors (i.e., errors that were correctly classified). The Ne/ERN was larger for partially aware errors than for fully aware errors. Whereas this speaks against the idea that the Ne/ERN foreshadows the degree of error awareness, it confirms the prediction of a computational model, which relates the Ne/ERN to post-response conflict. This model predicts that stronger distractor processing - a prerequisite of error classification in our paradigm - leads to lower post-response conflict and thus a smaller Ne/ERN. This implies that the relationship between Ne/ERN and error awareness depends on how error awareness is related to response conflict in a specific task. Our results further indicate that the Ne/ERN but not the degree of error awareness determines adaptive performance adjustments. Taken together, we conclude that the Ne/ERN is dissociable from error awareness and foreshadows adaptive performance adjustments. Our results suggest that the relationship between the Ne/ERN and error awareness is correlative and mediated by response conflict. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Myopia, spectacle wear, and risk of bicycle accidents among rural Chinese secondary school students: the Xichang Pediatric Refractive Error Study report no. 7.

    Science.gov (United States)

    Zhang, Mingzhi; Congdon, Nathan; Li, Liping; Song, Yue; Choi, Kai; Wang, Yunfei; Zhou, Zhongxia; Liu, Xiaojian; Sharma, Abhishek; Chen, Weihong; Lam, Dennis S C

    2009-06-01

    To study the effect of myopia and spectacle wear on bicycle-related injuries in rural Chinese students. Myopia is common among Chinese students but few studies have examined its effect on daily activities. Data on visual acuity, refractive error, current spectacle wear, and history of bicycle use and accidents during the past 3 years were sought from 1891 students undergoing eye examinations in rural Guangdong province. Refractive and accident data were available for 1539 participants (81.3%), among whom the mean age was 14.6 years, 52.5% were girls, 26.8% wore glasses, and 12.9% had myopia of less than -4 diopters in both eyes. More than 90% relied on bicycles to get to school daily. A total of 2931 accidents were reported by 423 participants, with 68 requiring medical attention. Male sex (odds ratio, 1.55; P accident, but habitual visual acuity and myopia were unassociated with the crash risk, after adjusting for age, sex, time spent riding, and risky riding behaviors. These results may be consistent with data on motor vehicle accidents implicating peripheral vision (potentially compromised by spectacle wear) more strongly than central visual acuity in mediating crash risk.

  6. Study on operator’s SA reliability in digital NPPs. Part 1: The analysis method of operator’s errors of situation awareness

    International Nuclear Information System (INIS)

    Li, Peng-cheng; Zhang, Li; Dai, Li-cao; Li, Xiao-Fang

    2017-01-01

    Highlights: • The model of ESA is established from an organization perspective, and it is new perspective. • The detailed classification system of ESA is developed based on the built ESA model. It is useful to identify the cause chain and root causes of organization causing ESA. • The analysis method of ESA is also constructed to guide the investigation of ESA event. A case study is provided to illustrate the concrete application of the method. - Abstract: Situation awareness (SA) is a key element that impacts operator’s decision-making and performance in nuclear power plants (NPPs). The subsequent complex cognitive activities cannot be correctly completed due to errors of situation awareness (ESA), which will lead to disastrous consequences. In order to investigate and analyze operator’s ESA in the digitized main control room (DMCR) of a nuclear power plant, the model of ESA is established, the classification system of ESA is developed based on the built ESA model, and the analysis method of ESA is also constructed on the basis of the observation of simulator and operator surveys. Finally, a case study is provided to illustrate the concrete application of the method. It provides a theoretical and practical support for the operator’s SAE analysis in a digitized main control room of a nuclear power plant.

  7. Spelling Errors of Dyslexic Children in Bosnian Language with Transparent Orthography

    Science.gov (United States)

    Duranovic, Mirela

    2017-01-01

    The purpose of this study was to explore the nature of spelling errors made by children with dyslexia in Bosnian language with transparent orthography. Three main error categories were distinguished: phonological, orthographic, and grammatical errors. An analysis of error type showed 86% of phonological errors, 10% of orthographic errors, and 4%…

  8. Repeated speech errors: evidence for learning.

    Science.gov (United States)

    Humphreys, Karin R; Menzies, Heather; Lake, Johanna K

    2010-11-01

    Three experiments elicited phonological speech errors using the SLIP procedure to investigate whether there is a tendency for speech errors on specific words to reoccur, and whether this effect can be attributed to implicit learning of an incorrect mapping from lemma to phonology for that word. In Experiment 1, when speakers made a phonological speech error in the study phase of the experiment (e.g. saying "beg pet" in place of "peg bet") they were over four times as likely to make an error on that same item several minutes later at test. A pseudo-error condition demonstrated that the effect is not simply due to a propensity for speakers to repeat phonological forms, regardless of whether or not they have been made in error. That is, saying "beg pet" correctly at study did not induce speakers to say "beg pet" in error instead of "peg bet" at test. Instead, the effect appeared to be due to learning of the error pathway. Experiment 2 replicated this finding, but also showed that after 48 h, errors made at study were no longer more likely to reoccur. As well as providing constraints on the longevity of the effect, this provides strong evidence that the error reoccurrences observed are not due to item-specific difficulty that leads individual speakers to make habitual mistakes on certain items. Experiment 3 showed that the diminishment of the effect 48 h later is not due to specific extra practice at the task. We discuss how these results fit in with a larger view of language as a dynamic system that is constantly adapting in response to experience. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Bias correction by use of errors-in-variables regression models in studies with K-X-ray fluorescence bone lead measurements.

    Science.gov (United States)

    Lamadrid-Figueroa, Héctor; Téllez-Rojo, Martha M; Angeles, Gustavo; Hernández-Ávila, Mauricio; Hu, Howard

    2011-01-01

    In-vivo measurement of bone lead by means of K-X-ray fluorescence (KXRF) is the preferred biological marker of chronic exposure to lead. Unfortunately, considerable measurement error associated with KXRF estimations can introduce bias in estimates of the effect of bone lead when this variable is included as the exposure in a regression model. Estimates of uncertainty reported by the KXRF instrument reflect the variance of the measurement error and, although they can be used to correct the measurement error bias, they are seldom used in epidemiological statistical analyzes. Errors-in-variables regression (EIV) allows for correction of bias caused by measurement error in predictor variables, based on the knowledge of the reliability of such variables. The authors propose a way to obtain reliability coefficients for bone lead measurements from uncertainty data reported by the KXRF instrument and compare, by the use of Monte Carlo simulations, results obtained using EIV regression models vs. those obtained by the standard procedures. Results of the simulations show that Ordinary Least Square (OLS) regression models provide severely biased estimates of effect, and that EIV provides nearly unbiased estimates. Although EIV effect estimates are more imprecise, their mean squared error is much smaller than that of OLS estimates. In conclusion, EIV is a better alternative than OLS to estimate the effect of bone lead when measured by KXRF. Copyright © 2010 Elsevier Inc. All rights reserved.

  10. Heuristics and Cognitive Error in Medical Imaging.

    Science.gov (United States)

    Itri, Jason N; Patel, Sohil H

    2018-05-01

    The field of cognitive science has provided important insights into mental processes underlying the interpretation of imaging examinations. Despite these insights, diagnostic error remains a major obstacle in the goal to improve quality in radiology. In this article, we describe several types of cognitive bias that lead to diagnostic errors in imaging and discuss approaches to mitigate cognitive biases and diagnostic error. Radiologists rely on heuristic principles to reduce complex tasks of assessing probabilities and predicting values into simpler judgmental operations. These mental shortcuts allow rapid problem solving based on assumptions and past experiences. Heuristics used in the interpretation of imaging studies are generally helpful but can sometimes result in cognitive biases that lead to significant errors. An understanding of the causes of cognitive biases can lead to the development of educational content and systematic improvements that mitigate errors and improve the quality of care provided by radiologists.

  11. Error Resilient Video Compression Using Behavior Models

    Directory of Open Access Journals (Sweden)

    Jacco R. Taal

    2004-03-01

    Full Text Available Wireless and Internet video applications are inherently subjected to bit errors and packet errors, respectively. This is especially so if constraints on the end-to-end compression and transmission latencies are imposed. Therefore, it is necessary to develop methods to optimize the video compression parameters and the rate allocation of these applications that take into account residual channel bit errors. In this paper, we study the behavior of a predictive (interframe video encoder and model the encoders behavior using only the statistics of the original input data and of the underlying channel prone to bit errors. The resulting data-driven behavior models are then used to carry out group-of-pictures partitioning and to control the rate of the video encoder in such a way that the overall quality of the decoded video with compression and channel errors is optimized.

  12. [Errors in Peruvian medical journals references].

    Science.gov (United States)

    Huamaní, Charles; Pacheco-Romero, José

    2009-01-01

    References are fundamental in our studies; an adequate selection is asimportant as an adequate description. To determine the number of errors in a sample of references found in Peruvian medical journals. We reviewed 515 scientific papers references selected by systematic randomized sampling and corroborated reference information with the original document or its citation in Pubmed, LILACS or SciELO-Peru. We found errors in 47,6% (245) of the references, identifying 372 types of errors; the most frequent were errors in presentation style (120), authorship (100) and title (100), mainly due to spelling mistakes (91). References error percentage was high, varied and multiple. We suggest systematic revision of references in the editorial process as well as to extend the discussion on this theme. references, periodicals, research, bibliometrics.

  13. Learning mechanisms to limit medication administration errors.

    Science.gov (United States)

    Drach-Zahavy, Anat; Pud, Dorit

    2010-04-01

    This paper is a report of a study conducted to identify and test the effectiveness of learning mechanisms applied by the nursing staff of hospital wards as a means of limiting medication administration errors. Since the influential report ;To Err Is Human', research has emphasized the role of team learning in reducing medication administration errors. Nevertheless, little is known about the mechanisms underlying team learning. Thirty-two hospital wards were randomly recruited. Data were collected during 2006 in Israel by a multi-method (observations, interviews and administrative data), multi-source (head nurses, bedside nurses) approach. Medication administration error was defined as any deviation from procedures, policies and/or best practices for medication administration, and was identified using semi-structured observations of nurses administering medication. Organizational learning was measured using semi-structured interviews with head nurses, and the previous year's reported medication administration errors were assessed using administrative data. The interview data revealed four learning mechanism patterns employed in an attempt to learn from medication administration errors: integrated, non-integrated, supervisory and patchy learning. Regression analysis results demonstrated that whereas the integrated pattern of learning mechanisms was associated with decreased errors, the non-integrated pattern was associated with increased errors. Supervisory and patchy learning mechanisms were not associated with errors. Superior learning mechanisms are those that represent the whole cycle of team learning, are enacted by nurses who administer medications to patients, and emphasize a system approach to data analysis instead of analysis of individual cases.

  14. TU-AB-201-05: Automatic Adaptive Per-Operative Re-Planning for HDR Prostate Brachytherapy - a Simulation Study On Errors in Needle Positioning

    International Nuclear Information System (INIS)

    Borot de Battisti, M; Maenhout, M; Lagendijk, J J W; Van Vulpen, M; Moerland, M A; Senneville, B Denis de; Hautvast, G; Binnekamp, D

    2015-01-01

    Purpose: To develop adaptive planning with feedback for MRI-guided focal HDR prostate brachytherapy with a single divergent needle robotic implant device. After each needle insertion, the dwell positions for that needle are calculated and the positioning of remaining needles and dosimetry are both updated based on MR imaging. Methods: Errors in needle positioning may occur due to inaccurate needle insertion (caused by e.g. the needle’s bending) and unpredictable changes in patient anatomy. Consequently, the dose plan quality might dramatically decrease compared to the preplan. In this study, a procedure was developed to re-optimize, after each needle insertion, the remaining needle angulations, source positions and dwell times in order to obtain an optimal coverage (D95% PTV>19 Gy) without exceeding the constraints of the organs at risk (OAR) (D10% urethra<21 Gy, D1cc bladder<12 Gy and D1cc rectum<12 Gy). Complete HDR procedures with 6 needle insertions were simulated for a patient MR-image set with PTV, prostate, urethra, bladder and rectum delineated. Random angulation errors, modeled by a Gaussian distribution (standard deviation of 3 mm at the needle’s tip), were generated for each needle insertion. We compared the final dose parameters for the situations (I) without re-optimization and (II) with the automatic feedback. Results: The computation time of replanning was below 100 seconds on a current desk computer. For the patient tested, a clinically acceptable dose plan was achieved while applying the automatic feedback (median(range) in Gy, D95% PTV: 19.9(19.3–20.3), D10% urethra: 13.4(11.9–18.0), D1cc rectum: 11.0(10.7–11.6), D1cc bladder: 4.9(3.6–6.8)). This was not the case without re-optimization (median(range) in Gy, D95% PTV: 19.4(14.9–21.3), D10% urethra: 12.6(11.0–15.7), D1cc rectum: 10.9(8.9–14.1), D1cc bladder: 4.8(4.4–5.2)). Conclusion: An automatic guidance strategy for HDR prostate brachytherapy was developed to compensate

  15. Minimum Error Entropy Classification

    CERN Document Server

    Marques de Sá, Joaquim P; Santos, Jorge M F; Alexandre, Luís A

    2013-01-01

    This book explains the minimum error entropy (MEE) concept applied to data classification machines. Theoretical results on the inner workings of the MEE concept, in its application to solving a variety of classification problems, are presented in the wider realm of risk functionals. Researchers and practitioners also find in the book a detailed presentation of practical data classifiers using MEE. These include multi‐layer perceptrons, recurrent neural networks, complexvalued neural networks, modular neural networks, and decision trees. A clustering algorithm using a MEE‐like concept is also presented. Examples, tests, evaluation experiments and comparison with similar machines using classic approaches, complement the descriptions.

  16. Assessment of quality of life of the children and parents affected by inborn errors of metabolism with restricted diet: preliminary results of a cross-sectional study.

    Science.gov (United States)

    Fabre, Alexandre; Baumstarck, Karine; Cano, Aline; Loundou, Anderson; Berbis, Julie; Chabrol, Brigitte; Auquier, Pascal

    2013-09-19

    The development in therapeutic strategies has increased survival of children affected by inborn errors of metabolism with restricted diet (IEMRD). These diseases have mild- and long-term consequences on the health. Little is known about the impact on the quality of life (QoL) of children and their families. The aims of this study were: to compare the QoL of the children and parents affected by IEMRD with the QoL of the general population and one pathology associated with long-term consequences. This cross-sectional study was performed at the French Reference Center for inborn metabolic disorders (Marseille, France). Inclusion criteria were: a child with a diagnosis of organic aciduria, urea cycle defect, or maple syrups urine disease (MSUD). Socio-demographics, clinical data, and QoL were recorded. Twenty-one of 32 eligible families were included during a planned routine visit. Ten (47%, 95% CI 27-69%) children were affected by organic aciduria, six (29%, 95% CI 10-48%) by urea cycle defects, and five (24%, 95% CI 6-42%) by MSUD. Among the younger children, the general well-being was significantly lower in the children with IEMRD than in the leukemia children (58 ± 16 versus 76 ± 15, p = 0.012), and among the older children, the leisure activities were significantly lower in the children with IEMRD than in the leukemia children (29 ± 18 versus 62 ± 22, p eating and neurologic disorders, enteral nutrition, and feeding modalities. The children and the parents of children affected presented altered 'physical' and 'social' QoL scores compared with the norms and patients with leukemia and their families. Future studies based on larger cohort studies should determine the different weights of potential predictive factors of QoL.

  17. Sugar-sweetened beverage intake and cardiovascular risk factor profile in youth with type 1 diabetes: application of measurement error methodology in the SEARCH Nutrition Ancillary Study.

    Science.gov (United States)

    Liese, Angela D; Crandell, Jamie L; Tooze, Janet A; Kipnis, Victor; Bell, Ronny; Couch, Sarah C; Dabelea, Dana; Crume, Tessa L; Mayer-Davis, Elizabeth J

    2015-08-14

    The SEARCH Nutrition Ancillary Study aims to investigate the role of dietary intake on the development of long-term complications of type 1 diabetes in youth, and capitalise on measurement error (ME) adjustment methodology. Using the National Cancer Institute (NCI) method for episodically consumed foods, we evaluated the relationship between sugar-sweetened beverage (SSB) intake and cardiovascular risk factor profile, with the application of ME adjustment methodology. The calibration sample included 166 youth with two FFQ and three 24 h dietary recall data within 1 month. The full sample included 2286 youth with type 1 diabetes. SSB intake was significantly associated with higher TAG, total and LDL-cholesterol concentrations, after adjusting for energy, age, diabetes duration, race/ethnicity, sex and education. The estimated effect size was larger (model coefficients increased approximately 3-fold) after the application of the NCI method than without adjustment for ME. Compared with individuals consuming one serving of SSB every 2 weeks, those who consumed one serving of SSB every 2 d had 3.7 mg/dl (0.04 mmol/l) higher TAG concentrations and 4.0 mg/dl (0.10 mmol/l) higher total cholesterol and LDL-cholesterol concentrations, after adjusting for ME and covariates. SSB intake was not associated with measures of adiposity and blood pressure. Our findings suggest that SSB intake is significantly related to increased lipid levels in youth with type 1 diabetes, and that estimates of the effect size of SSB on lipid levels are severely attenuated in the presence of ME. Future studies in youth with diabetes should consider a design that will allow for the adjustment for ME when studying the influence of diet on health status.

  18. Common Errors in Ecological Data Sharing

    Directory of Open Access Journals (Sweden)

    Robert B. Cook

    2013-04-01

    Full Text Available Objectives: (1 to identify common errors in data organization and metadata completeness that would preclude a “reader” from being able to interpret and re-use the data for a new purpose; and (2 to develop a set of best practices derived from these common errors that would guide researchers in creating more usable data products that could be readily shared, interpreted, and used.Methods: We used directed qualitative content analysis to assess and categorize data and metadata errors identified by peer reviewers of data papers published in the Ecological Society of America’s (ESA Ecological Archives. Descriptive statistics provided the relative frequency of the errors identified during the peer review process.Results: There were seven overarching error categories: Collection & Organization, Assure, Description, Preserve, Discover, Integrate, and Analyze/Visualize. These categories represent errors researchers regularly make at each stage of the Data Life Cycle. Collection & Organization and Description errors were some of the most common errors, both of which occurred in over 90% of the papers.Conclusions: Publishing data for sharing and reuse is error prone, and each stage of the Data Life Cycle presents opportunities for mistakes. The most common errors occurred when the researcher did not provide adequate metadata to enable others to interpret and potentially re-use the data. Fortunately, there are ways to minimize these mistakes through carefully recording all details about study context, data collection, QA/ QC, and analytical procedures from the beginning of a research project and then including this descriptive information in the metadata.

  19. Towards reporting standards for neuropsychological study results: A proposal to minimize communication errors with standardized qualitative descriptors for normalized test scores.

    Science.gov (United States)

    Schoenberg, Mike R; Rum, Ruba S

    2017-11-01

    Rapid, clear and efficient communication of neuropsychological results is essential to benefit patient care. Errors in communication are a lead cause of medical errors; nevertheless, there remains a lack of consistency in how neuropsychological scores are communicated. A major limitation in the communication of neuropsychological results is the inconsistent use of qualitative descriptors for standardized test scores and the use of vague terminology. PubMed search from 1 Jan 2007 to 1 Aug 2016 to identify guidelines or consensus statements for the description and reporting of qualitative terms to communicate neuropsychological test scores was conducted. The review found the use of confusing and overlapping terms to describe various ranges of percentile standardized test scores. In response, we propose a simplified set of qualitative descriptors for normalized test scores (Q-Simple) as a means to reduce errors in communicating test results. The Q-Simple qualitative terms are: 'very superior', 'superior', 'high average', 'average', 'low average', 'borderline' and 'abnormal/impaired'. A case example illustrates the proposed Q-Simple qualitative classification system to communicate neuropsychological results for neurosurgical planning. The Q-Simple qualitative descriptor system is aimed as a means to improve and standardize communication of standardized neuropsychological test scores. Research are needed to further evaluate neuropsychological communication errors. Conveying the clinical implications of neuropsychological results in a manner that minimizes risk for communication errors is a quintessential component of evidence-based practice. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Detected-jump-error-correcting quantum codes, quantum error designs, and quantum computation

    International Nuclear Information System (INIS)

    Alber, G.; Mussinger, M.; Beth, Th.; Charnes, Ch.; Delgado, A.; Grassl, M.

    2003-01-01

    The recently introduced detected-jump-correcting quantum codes are capable of stabilizing qubit systems against spontaneous decay processes arising from couplings to statistically independent reservoirs. These embedded quantum codes exploit classical information about which qubit has emitted spontaneously and correspond to an active error-correcting code embedded in a passive error-correcting code. The construction of a family of one-detected-jump-error-correcting quantum codes is shown and the optimal redundancy, encoding, and recovery as well as general properties of detected-jump-error-correcting quantum codes are discussed. By the use of design theory, multiple-jump-error-correcting quantum codes can be constructed. The performance of one-jump-error-correcting quantum codes under nonideal conditions is studied numerically by simulating a quantum memory and Grover's algorithm

  1. Wind power error estimation in resource assessments.

    Directory of Open Access Journals (Sweden)

    Osvaldo Rodríguez

    Full Text Available Estimating the power output is one of the elements that determine the techno-economic feasibility of a renewable project. At present, there is a need to develop reliable methods that achieve this goal, thereby contributing to wind power penetration. In this study, we propose a method for wind power error estimation based on the wind speed measurement error, probability density function, and wind turbine power curves. This method uses the actual wind speed data without prior statistical treatment based on 28 wind turbine power curves, which were fitted by Lagrange's method, to calculate the estimate wind power output and the corresponding error propagation. We found that wind speed percentage errors of 10% were propagated into the power output estimates, thereby yielding an error of 5%. The proposed error propagation complements the traditional power resource assessments. The wind power estimation error also allows us to estimate intervals for the power production leveled cost or the investment time return. The implementation of this method increases the reliability of techno-economic resource assessment studies.

  2. Wind power error estimation in resource assessments.

    Science.gov (United States)

    Rodríguez, Osvaldo; Del Río, Jesús A; Jaramillo, Oscar A; Martínez, Manuel

    2015-01-01

    Estimating the power output is one of the elements that determine the techno-economic feasibility of a renewable project. At present, there is a need to develop reliable methods that achieve this goal, thereby contributing to wind power penetration. In this study, we propose a method for wind power error estimation based on the wind speed measurement error, probability density function, and wind turbine power curves. This method uses the actual wind speed data without prior statistical treatment based on 28 wind turbine power curves, which were fitted by Lagrange's method, to calculate the estimate wind power output and the corresponding error propagation. We found that wind speed percentage errors of 10% were propagated into the power output estimates, thereby yielding an error of 5%. The proposed error propagation complements the traditional power resource assessments. The wind power estimation error also allows us to estimate intervals for the power production leveled cost or the investment time return. The implementation of this method increases the reliability of techno-economic resource assessment studies.

  3. Standard Errors for Matrix Correlations.

    Science.gov (United States)

    Ogasawara, Haruhiko

    1999-01-01

    Derives the asymptotic standard errors and intercorrelations for several matrix correlations assuming multivariate normality for manifest variables and derives the asymptotic standard errors of the matrix correlations for two factor-loading matrices. (SLD)

  4. Time-order errors and standard-position effects in duration discrimination: An experimental study and an analysis by the sensation-weighting model.

    Science.gov (United States)

    Hellström, Åke; Rammsayer, Thomas H

    2015-10-01

    Studies have shown that the discriminability of successive time intervals depends on the presentation order of the standard (St) and the comparison (Co) stimuli. Also, this order affects the point of subjective equality. The first effect is here called the standard-position effect (SPE); the latter is known as the time-order error. In the present study, we investigated how these two effects vary across interval types and standard durations, using Hellström's sensation-weighting model to describe the results and relate them to stimulus comparison mechanisms. In Experiment 1, four modes of interval presentation were used, factorially combining interval type (filled, empty) and sensory modality (auditory, visual). For each mode, two presentation orders (St-Co, Co-St) and two standard durations (100 ms, 1,000 ms) were used; half of the participants received correctness feedback, and half of them did not. The interstimulus interval was 900 ms. The SPEs were negative (i.e., a smaller difference limen for St-Co than for Co-St), except for the filled-auditory and empty-visual 100-ms standards, for which a positive effect was obtained. In Experiment 2, duration discrimination was investigated for filled auditory intervals with four standards between 100 and 1,000 ms, an interstimulus interval of 900 ms, and no feedback. Standard duration interacted with presentation order, here yielding SPEs that were negative for standards of 100 and 1,000 ms, but positive for 215 and 464 ms. Our findings indicate that the SPE can be positive as well as negative, depending on the interval type and standard duration, reflecting the relative weighting of the stimulus information, as is described by the sensation-weighting model.

  5. Error forecasting schemes of error correction at receiver

    International Nuclear Information System (INIS)

    Bhunia, C.T.

    2007-08-01

    To combat error in computer communication networks, ARQ (Automatic Repeat Request) techniques are used. Recently Chakraborty has proposed a simple technique called the packet combining scheme in which error is corrected at the receiver from the erroneous copies. Packet Combining (PC) scheme fails: (i) when bit error locations in erroneous copies are the same and (ii) when multiple bit errors occur. Both these have been addressed recently by two schemes known as Packet Reversed Packet Combining (PRPC) Scheme, and Modified Packet Combining (MPC) Scheme respectively. In the letter, two error forecasting correction schemes are reported, which in combination with PRPC offer higher throughput. (author)

  6. A study of the positioning errors of head and neck in the process of intensity modulation radiated therapy of nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Lin Chengguang; Lin Liuwen; Liu Bingti; Liu Xiaomao; Li Guowen

    2011-01-01

    Objective: To investigate the positioning errors of head and neck during intensity-modulated radiation therapy of nasopharyngeal carcinoma. Methods: Nineteen patients with middle-advanced nasopharyngeal carcinoma (T 2-4 N 1-3 M 0 ), treated by intensity-modulated radiation therapy, underwent repeated CT during their 6-week treatment course. All the patients were immobilized by head-neck-shoulder thermoplastic mask. We evaluated their anatomic landmark coordinated in a total of 66 repeated CT data sets and respective x, y, z shifts relative to their position in the planning CT. Results: The positioning error of the neck was 2.44 mm ± 2.24 mm, 2.05 mm ± 1.42 mm, 1.83 mm ± 1.53 mm in x, y, z respectively. And that of the head was 1.05 mm ± 0.87 mm, 1.23 mm ± 1.05 mm, 1.17 mm ± 1.55 mm respectively. The positioning error between neck and head have respectively statistical difference (t=-6.58, -5.28, -3.42, P=0.000, 0.000, 0.001). The system error of the neck was 2.33, 1.67 and 1.56 higher than that of the head, respectively in left-right, vertical and head-foot directions; and the random error of neck was 2.57, 1.34 and 0.99 higher than that of head respectively. Conclusions: In the process of the intensity-modulated radiation therapy of nasopharyngeal carcinoma, with the immobilization by head-neck-shoulder thermoplastic mask, the positioning error of neck is higher than that of head. (authors)

  7. Condom Use Errors and Problems: A Comparative Study of HIV-Positive Versus HIV-Negative Young Black Men Who Have Sex With Men.

    Science.gov (United States)

    Crosby, Richard; Mena, Leandro; Yarber, William L; Graham, Cynthia A; Sanders, Stephanie A; Milhausen, Robin R

    2015-11-01

    To describe self-reported frequencies of selected condom use errors and problems among young (age, 15-29 years) black men who have sex with men (YBMSM) and to compare the observed prevalence of these errors/problems by HIV serostatus. Between September 2012 October 2014, electronic interview data were collected from 369 YBMSM attending a federally supported sexually transmitted infection clinic located in the southern United States. Seventeen condom use errors and problems were assessed. χ(2) Tests were used to detect significant differences in the prevalence of these 17 errors and problems between HIV-negative and HIV-positive men. The recall period was the past 90 days. The overall mean (SD) number of errors/problems was 2.98 (2.29). The mean (SD) for HIV-negative men was 2.91 (2.15), and the mean (SD) for HIV-positive men was 3.18 (2.57). These means were not significantly different (t = 1.02, df = 367, P = 0.31). Only 2 significant differences were observed between HIV-negative and HIV-positive men. Breakage (P = 0.002) and slippage (P = 0.005) were about twice as likely among HIV-positive men. Breakage occurred for nearly 30% of the HIV-positive men compared with approximately 15% among HIV-negative men. Slippage occurred for approximately 16% of the HIV-positive men compared with approximately 9% among HIV-negative men. A need exists to help YBMSM acquire the skills needed to avert breakage and slippage issues that could lead to HIV transmission. Beyond these 2 exceptions, condom use errors and problems were ubiquitous in this population regardless of HIV serostatus. Clinic-based intervention is warranted for these young men, including education about correct condom use and provision of free condoms and long-lasting lubricants.

  8. Evaluating a medical error taxonomy.

    OpenAIRE

    Brixey, Juliana; Johnson, Todd R.; Zhang, Jiajie

    2002-01-01

    Healthcare has been slow in using human factors principles to reduce medical errors. The Center for Devices and Radiological Health (CDRH) recognizes that a lack of attention to human factors during product development may lead to errors that have the potential for patient injury, or even death. In response to the need for reducing medication errors, the National Coordinating Council for Medication Errors Reporting and Prevention (NCC MERP) released the NCC MERP taxonomy that provides a stand...

  9. Imaging and dosimetric errors in 4D PET/CT-guided radiotherapy from patient-specific