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Sample records for strong external validity

  1. Checklists for external validity

    DEFF Research Database (Denmark)

    Dyrvig, Anne-Kirstine; Kidholm, Kristian; Gerke, Oke

    2014-01-01

    to an implementation setting. In this paper, currently available checklists on external validity are identified, assessed and used as a basis for proposing a new improved instrument. METHOD: A systematic literature review was carried out in Pubmed, Embase and Cinahl on English-language papers without time restrictions....... The retrieved checklist items were assessed for (i) the methodology used in primary literature, justifying inclusion of each item; and (ii) the number of times each item appeared in checklists. RESULTS: Fifteen papers were identified, presenting a total of 21 checklists for external validity, yielding a total...... of 38 checklist items. Empirical support was considered the most valid methodology for item inclusion. Assessment of methodological justification showed that none of the items were supported empirically. Other kinds of literature justified the inclusion of 22 of the items, and 17 items were included...

  2. Quantum electrodynamics in strong external fields

    International Nuclear Information System (INIS)

    Mueller, B.; Rafelski, J.; Kirsch, J.

    1981-05-01

    We review the theoretical description of quantum electrodynamics in the presence of strong and supercritical fields. In particular, the process of the spontaneous vacuum decay accompanied by the observable positron emission in heavy ion collisions is described. Emphasis is put on the proper formulation of many-body aspects in the framework of quantum field theory. The extension of the theory to the description of Bose fields and many-body effects is presented, and the Klein paradox is resolved. Some implications of the theoretical methods developed here are presented concerning non-abelian gauge theories and the quark confinement puzzle. (orig.)

  3. Confinement of laser plasma expansion with strong external magnetic field

    Science.gov (United States)

    Tang, Hui-bo; Hu, Guang-yue; Liang, Yi-han; Tao, Tao; Wang, Yu-lin; Hu, Peng; Zhao, Bin; Zheng, Jian

    2018-05-01

    The evolutions of laser ablation plasma, expanding in strong (∼10 T) transverse external magnetic field, were investigated in experiments and simulations. The experimental results show that the magnetic field pressure causes the plasma decelerate and accumulate at the plasma-field interface, and then form a low-density plasma bubble. The saturation size of the plasma bubble has a scaling law on laser energy and magnetic field intensity. Magnetohydrodynamic simulation results support the observation and find that the scaling law (V max ∝ E p /B 2, where V max is the maximum volume of the plasma bubble, E p is the absorbed laser energy, and B is the magnetic field intensity) is effective in a broad laser energy range from several joules to kilo-joules, since the plasma is always in the state of magnetic field frozen while expanding. About 15% absorbed laser energy converts into magnetic field energy stored in compressed and curved magnetic field lines. The duration that the plasma bubble comes to maximum size has another scaling law t max ∝ E p 1/2/B 2. The plasma expanding dynamics in external magnetic field have a similar character with that in underdense gas, which indicates that the external magnetic field may be a feasible approach to replace the gas filled in hohlraum to suppress the wall plasma expansion and mitigate the stimulated scattering process in indirect drive ignition.

  4. Geochemistry Model Validation Report: External Accumulation Model

    International Nuclear Information System (INIS)

    Zarrabi, K.

    2001-01-01

    The purpose of this Analysis and Modeling Report (AMR) is to validate the External Accumulation Model that predicts accumulation of fissile materials in fractures and lithophysae in the rock beneath a degrading waste package (WP) in the potential monitored geologic repository at Yucca Mountain. (Lithophysae are voids in the rock having concentric shells of finely crystalline alkali feldspar, quartz, and other materials that were formed due to entrapped gas that later escaped, DOE 1998, p. A-25.) The intended use of this model is to estimate the quantities of external accumulation of fissile material for use in external criticality risk assessments for different types of degrading WPs: U.S. Department of Energy (DOE) Spent Nuclear Fuel (SNF) codisposed with High Level Waste (HLW) glass, commercial SNF, and Immobilized Plutonium Ceramic (Pu-ceramic) codisposed with HLW glass. The scope of the model validation is to (1) describe the model and the parameters used to develop the model, (2) provide rationale for selection of the parameters by comparisons with measured values, and (3) demonstrate that the parameters chosen are the most conservative selection for external criticality risk calculations. To demonstrate the applicability of the model, a Pu-ceramic WP is used as an example. The model begins with a source term from separately documented EQ6 calculations; where the source term is defined as the composition versus time of the water flowing out of a breached waste package (WP). Next, PHREEQC, is used to simulate the transport and interaction of the source term with the resident water and fractured tuff below the repository. In these simulations the primary mechanism for accumulation is mixing of the high pH, actinide-laden source term with resident water; thus lowering the pH values sufficiently for fissile minerals to become insoluble and precipitate. In the final section of the model, the outputs from PHREEQC, are processed to produce mass of accumulation

  5. Convergent validity test, construct validity test and external validity test of the David Liberman algorithm

    Directory of Open Access Journals (Sweden)

    David Maldavsky

    2013-08-01

    Full Text Available The author first exposes a complement of a previous test about convergent validity, then a construct validity test and finally an external validity test of the David Liberman algorithm.  The first part of the paper focused on a complementary aspect, the differential sensitivity of the DLA 1 in an external comparison (to other methods, and 2 in an internal comparison (between two ways of using the same method, the DLA.  The construct validity test exposes the concepts underlined to DLA, their operationalization and some corrections emerging from several empirical studies we carried out.  The external validity test examines the possibility of using the investigation of a single case and its relation with the investigation of a more extended sample.

  6. Reconceptualising the external validity of discrete choice experiments.

    Science.gov (United States)

    Lancsar, Emily; Swait, Joffre

    2014-10-01

    External validity is a crucial but under-researched topic when considering using discrete choice experiment (DCE) results to inform decision making in clinical, commercial or policy contexts. We present the theory and tests traditionally used to explore external validity that focus on a comparison of final outcomes and review how this traditional definition has been empirically tested in health economics and other sectors (such as transport, environment and marketing) in which DCE methods are applied. While an important component, we argue that the investigation of external validity should be much broader than a comparison of final outcomes. In doing so, we introduce a new and more comprehensive conceptualisation of external validity, closely linked to process validity, that moves us from the simple characterisation of a model as being or not being externally valid on the basis of predictive performance, to the concept that external validity should be an objective pursued from the initial conceptualisation and design of any DCE. We discuss how such a broader definition of external validity can be fruitfully used and suggest innovative ways in which it can be explored in practice.

  7. External Validation of a Prediction Model for Successful External Cephalic Version

    NARCIS (Netherlands)

    de Hundt, Marcella; Vlemmix, Floortje; Kok, Marjolein; van der Steeg, Jan W.; Bais, Joke M.; Mol, Ben W.; van der Post, Joris A.

    2012-01-01

    We sought external validation of a prediction model for the probability of a successful external cephalic version (ECV). We evaluated the performance of the prediction model with calibration and discrimination. For clinical practice, we developed a score chart to calculate the probability of a

  8. External validation of EPIWIN biodegradation models.

    Science.gov (United States)

    Posthumus, R; Traas, T P; Peijnenburg, W J G M; Hulzebos, E M

    2005-01-01

    The BIOWIN biodegradation models were evaluated for their suitability for regulatory purposes. BIOWIN includes the linear and non-linear BIODEG and MITI models for estimating the probability of rapid aerobic biodegradation and an expert survey model for primary and ultimate biodegradation estimation. Experimental biodegradation data for 110 newly notified substances were compared with the estimations of the different models. The models were applied separately and in combinations to determine which model(s) showed the best performance. The results of this study were compared with the results of other validation studies and other biodegradation models. The BIOWIN models predict not-readily biodegradable substances with high accuracy in contrast to ready biodegradability. In view of the high environmental concern of persistent chemicals and in view of the large number of not-readily biodegradable chemicals compared to the readily ones, a model is preferred that gives a minimum of false positives without a corresponding high percentage false negatives. A combination of the BIOWIN models (BIOWIN2 or BIOWIN6) showed the highest predictive value for not-readily biodegradability. However, the highest score for overall predictivity with lowest percentage false predictions was achieved by applying BIOWIN3 (pass level 2.75) and BIOWIN6.

  9. Assessing Discriminative Performance at External Validation of Clinical Prediction Models.

    Directory of Open Access Journals (Sweden)

    Daan Nieboer

    Full Text Available External validation studies are essential to study the generalizability of prediction models. Recently a permutation test, focusing on discrimination as quantified by the c-statistic, was proposed to judge whether a prediction model is transportable to a new setting. We aimed to evaluate this test and compare it to previously proposed procedures to judge any changes in c-statistic from development to external validation setting.We compared the use of the permutation test to the use of benchmark values of the c-statistic following from a previously proposed framework to judge transportability of a prediction model. In a simulation study we developed a prediction model with logistic regression on a development set and validated them in the validation set. We concentrated on two scenarios: 1 the case-mix was more heterogeneous and predictor effects were weaker in the validation set compared to the development set, and 2 the case-mix was less heterogeneous in the validation set and predictor effects were identical in the validation and development set. Furthermore we illustrated the methods in a case study using 15 datasets of patients suffering from traumatic brain injury.The permutation test indicated that the validation and development set were homogenous in scenario 1 (in almost all simulated samples and heterogeneous in scenario 2 (in 17%-39% of simulated samples. Previously proposed benchmark values of the c-statistic and the standard deviation of the linear predictors correctly pointed at the more heterogeneous case-mix in scenario 1 and the less heterogeneous case-mix in scenario 2.The recently proposed permutation test may provide misleading results when externally validating prediction models in the presence of case-mix differences between the development and validation population. To correctly interpret the c-statistic found at external validation it is crucial to disentangle case-mix differences from incorrect regression coefficients.

  10. Internal and external validation of an ESTRO delineation guideline

    DEFF Research Database (Denmark)

    Eldesoky, Ahmed R.; Yates, Esben Svitzer; Nyeng, Tine B

    2016-01-01

    Background and purpose To internally and externally validate an atlas based automated segmentation (ABAS) in loco-regional radiation therapy of breast cancer. Materials and methods Structures of 60 patients delineated according to the ESTRO consensus guideline were included in four categorized...... and axillary nodal levels and poor agreement for interpectoral, internal mammary nodal regions and LADCA. Correcting ABAS significantly improved all the results. External validation of ABAS showed comparable results. Conclusions ABAS is a clinically useful tool for segmenting structures in breast cancer loco...

  11. Development and external validation of a new PTA assessment scale

    NARCIS (Netherlands)

    Jacobs, B.; van Ekert, J.; Vernooy, L.P.; Dieperink, P.; Andriessen, T.M.J.C.; Hendriks, M.P.; van Vugt, A.B.; Emons, M.A.; Borm, G.F.; Vos, P.E.

    2012-01-01

    BACKGROUND: Post-traumatic amnesia (PTA) is a key symptom of traumatic brain injury (TBI). Accurate assessment of PTA is imperative in guiding clinical decision making. Our aim was to develop and externally validate a short, examiner independent and practical PTA scale, by selecting the most

  12. EXTERNAL VALIDATION OF THE DIABETES EARLY READMISSION RISK INDICATOR (DERRI™).

    Science.gov (United States)

    Rubin, Daniel J; Recco, Dominic; Turchin, Alexander; Zhao, Huaqing; Golden, Sherita Hill

    2018-04-06

    The Diabetes Early Readmission Risk Indicator (DERRI ™ ) was previously developed and internally validated as a tool to predict the risk of all-cause readmission within 30 days of discharge (30-d readmission) of hospitalized patients with diabetes. In this study, the predictive performance of the DERRI ™ with and without additional predictors was assessed in an external sample. We conducted a retrospective cohort study of adult patients with diabetes discharged from 2 academic medical centers between 1/1/2000 and 12/31/2014. We applied the previously developed DERRI ™ , which includes admission laboratory results, sociodemographics, a diagnosis of certain comorbidities, and recent discharge information, and evaluated the effect of adding metabolic indicators on predictive performance using multivariable logistic regression. Total cholesterol and A1c were selected based on clinical relevance and univariate association with 30-d readmission. Among 105,974 discharges, 19,032 (18.0%) were followed by 30-d readmission for any cause. The DERRI ™ had a C-statistic of 0.634 for 30-d readmission. Total cholesterol (TC) was the lipid parameter most strongly associated with 30-d readmission. The DERRI ™ predictors, A1c, and TC were significantly associated with 30-d readmission; however, their addition to the DERRI ™ did not significantly change model performance (C-statistic 0.643 [95% CI, 0.638-0.647], p=0.92). Performance of the DERRI ™ in this external cohort was modest but comparable to other readmission prediction models. Addition of A1c and TC to the DERRI ™ did not significantly improve performance. Although the DERRI ™ may be useful to direct resources toward diabetes patients at higher risk, better prediction is needed. DERRI = Diabetes Early Readmission Risk Indicator; TC = Total cholesterol; A1c = hemoglobin A1c; HDL-C = high-density lipoprotein cholesterol; LDL-C = low-density lipoprotein cholesterol; DKA = diabetic ketoacidosis; HHS

  13. Development and external validation of a new PTA assessment scale

    Directory of Open Access Journals (Sweden)

    Jacobs Bram

    2012-08-01

    Full Text Available Abstract Background Post-traumatic amnesia (PTA is a key symptom of traumatic brain injury (TBI. Accurate assessment of PTA is imperative in guiding clinical decision making. Our aim was to develop and externally validate a short, examiner independent and practical PTA scale, by selecting the most discriminative items from existing scales and using a three-word memory test. Methods Mild, moderate and severe TBI patients and control subjects were assessed in two separate cohorts, one for derivation and one for validation, using a questionnaire comprised of items from existing PTA scales. We tested which individual items best discriminated between TBI patients and controls, represented by sensitivity and specificity. We then created our PTA scale based on these results. This new scale was externally evaluated for its discriminative value using Receiver Operating Characteristic (ROC analysis and compared to existing PTA scales. Results The derivation cohort included 126 TBI patients and 31 control subjects; the validation cohort consisted of 132 patients and 30 controls. A set of seven items was eventually selected to comprise the new PTA scale: age, name of hospital, time, day of week, month, mode of transport and recall of three words. This scale demonstrated adequate discriminative values compared to existing PTA scales on three consecutive administrations in the validation cohort. Conclusion We introduce a valid, practical and examiner independent PTA scale, which is suitable for mild TBI patients at the emergency department and yet still valuable for the follow-up of more severely injured TBI patients.

  14. Particle production in field theories coupled to strong external sources, I: Formalism and main results

    International Nuclear Information System (INIS)

    Gelis, Francois; Venugopalan, Raju

    2006-01-01

    We develop a formalism for particle production in a field theory coupled to a strong time-dependent external source. An example of such a theory is the color glass condensate. We derive a formula, in terms of cut vacuum-vacuum Feynman graphs, for the probability of producing a given number of particles. This formula is valid to all orders in the coupling constant. The distribution of multiplicities is non-Poissonian, even in the classical approximation. We investigate an alternative method of calculating the mean multiplicity. At leading order, the average multiplicity can be expressed in terms of retarded solutions of classical equations of motion. We demonstrate that the average multiplicity at next-to-leading order can be formulated as an initial value problem by solving equations of motion for small fluctuation fields with retarded boundary conditions. The variance of the distribution can be calculated in a similar fashion. Our formalism therefore provides a framework to compute from first principles particle production in proton-nucleus and nucleus-nucleus collisions beyond leading order in the coupling constant and to all orders in the source density. We also provide a transparent interpretation (in conventional field theory language) of the well-known Abramovsky-Gribov-Kancheli (AGK) cancellations. Explicit connections are made between the framework for multi-particle production developed here and the framework of reggeon field theory

  15. Threshold for strong thermal dephasing in periodically poled KTP in external cavity frequency doubling

    DEFF Research Database (Denmark)

    Lundeman, Jesper Holm; Jensen, Ole Bjarlin; Andersen, Peter E.

    2009-01-01

    We present a measurement series of the efficiency of periodically poled KTP used for second-harmonic generation in an external phase-locked cavity. Due to the high absorption (0.01 cm^−1) in the PPKTP crystal at the pump wavelength a strong thermal dephasing of the periodically poled grating...

  16. Spin polarization in high density quark matter under a strong external magnetic field

    DEFF Research Database (Denmark)

    Tsue, Yasuhiko; Da Providência, João; Providência, Constança

    2016-01-01

    In high density quark matter under a strong external magnetic field, possible phases are investigated by using the two-flavor Nambu-Jona-Lasinio (NJL) model with tensor-type four-point interaction between quarks, as well as the axial-vector-type four-point interaction. In the tensor-type interact...

  17. Validation of a scenario-based assessment of critical thinking using an externally validated tool.

    Science.gov (United States)

    Buur, Jennifer L; Schmidt, Peggy; Smylie, Dean; Irizarry, Kris; Crocker, Carlos; Tyler, John; Barr, Margaret

    2012-01-01

    With medical education transitioning from knowledge-based curricula to competency-based curricula, critical thinking skills have emerged as a major competency. While there are validated external instruments for assessing critical thinking, many educators have created their own custom assessments of critical thinking. However, the face validity of these assessments has not been challenged. The purpose of this study was to compare results from a custom assessment of critical thinking with the results from a validated external instrument of critical thinking. Students from the College of Veterinary Medicine at Western University of Health Sciences were administered a custom assessment of critical thinking (ACT) examination and the externally validated instrument, California Critical Thinking Skills Test (CCTST), in the spring of 2011. Total scores and sub-scores from each exam were analyzed for significant correlations using Pearson correlation coefficients. Significant correlations between ACT Blooms 2 and deductive reasoning and total ACT score and deductive reasoning were demonstrated with correlation coefficients of 0.24 and 0.22, respectively. No other statistically significant correlations were found. The lack of significant correlation between the two examinations illustrates the need in medical education to externally validate internal custom assessments. Ultimately, the development and validation of custom assessments of non-knowledge-based competencies will produce higher quality medical professionals.

  18. Properties of color-flavor locked strange quark matter in an external strong magnetic field

    Institute of Scientific and Technical Information of China (English)

    崔帅帅; 彭光雄; 陆振烟; 彭程; 徐建峰

    2015-01-01

    The properties of color-flavor locked strange quark matter in an external strong magnetic field are investigated in a quark model with density-dependent quark masses. Parameters are determined by stability arguments. It is found that the minimum energy per baryon of the color-flavor locked (MCFL) matter decreases with increasing magnetic-field strength in a certain range, which makes MCFL matter more stable than other phases within a proper magnitude of the external magnetic field. However, if the energy of the field itself is added, the total energy per baryon will increase.

  19. External validity of post-stroke interventional gait rehabilitation studies.

    Science.gov (United States)

    Kafri, Michal; Dickstein, Ruth

    2017-01-01

    Gait rehabilitation is a major component of stroke rehabilitation, and is supported by extensive research. The objective of this review was to examine the external validity of intervention studies aimed at improving gait in individuals post-stroke. To that end, two aspects of these studies were assessed: subjects' exclusion criteria and the ecological validity of the intervention, as manifested by the intervention's technological complexity and delivery setting. Additionally, we examined whether the target population as inferred from the titles/abstracts is broader than the population actually represented by the reported samples. We systematically researched PubMed for intervention studies to improve gait post-stroke, working backwards from the beginning of 2014. Exclusion criteria, the technological complexity of the intervention (defined as either elaborate or simple), setting, and description of the target population in the titles/abstracts were recorded. Fifty-two studies were reviewed. The samples were exclusive, with recurrent stroke, co-morbidities, cognitive status, walking level, and residency being major reasons for exclusion. In one half of the studies, the intervention was elaborate. Descriptions of participants in the title/abstract in almost one half of the studies included only the diagnosis (stroke or comparable terms) and its stage (acute, subacute, and chronic). The external validity of a substantial number of intervention studies about rehabilitation of gait post-stroke appears to be limited by exclusivity of the samples as well as by deficiencies in ecological validity of the interventions. These limitations are not accurately reflected in the titles or abstracts of the studies.

  20. Review of external validity reporting in childhood obesity prevention research.

    Science.gov (United States)

    Klesges, Lisa M; Dzewaltowski, David A; Glasgow, Russell E

    2008-03-01

    The translation and dissemination of prevention intervention evidence into practice is needed to address significant public health issues such as childhood obesity. Increased attention to and reporting of external validity information in research publications would allow for better understanding of generalizability issues relevant to successful translation. To demonstrate this potential, recent reports of childhood obesity prevention interventions were evaluated on the extent to which external validity dimensions were reported. Childhood obesity prevention studies that were controlled, long-term research trials published between 1980 and 2004 that reported a behavioral target of physical activity and/or healthy eating along with at least one anthropometric outcome were identified in 2005. Studies were summarized between 2005 and 2006 using review criteria developed by Green and Glasgow in 2006. Nineteen publications met selection criteria. In general, all studies lacked full reporting on potential generalizability and dissemination elements. Median reporting over all elements was 34.5%; the mode was 0% with a range of 0% to 100%. Most infrequent were reports of setting level selection criteria and representativeness, characteristics regarding intervention staff, implementation of intervention content, costs, and program sustainability. The evidence base for future prevention interventions can be improved by enhancing the reporting of contextual and generalizability elements central to translational research. Such efforts face practical hurdles but could provide additional explanation for variability in intervention outcomes, insights into successful adaptations of interventions, and help guide policy decisions.

  1. External Validation of the HERNIAscore: An Observational Study.

    Science.gov (United States)

    Cherla, Deepa V; Moses, Maya L; Mueck, Krislynn M; Hannon, Craig; Ko, Tien C; Kao, Lillian S; Liang, Mike K

    2017-09-01

    The HERNIAscore is a ventral incisional hernia (VIH) risk assessment tool that uses only preoperative variables and predictable intraoperative variables. The aim of this study was to validate and modify, if needed, the HERNIAscore in an external dataset. This was a retrospective observational study of all patients undergoing resection for gastrointestinal malignancy from 2011 through 2015 at a safety-net hospital. The primary end point was clinical postoperative VIH. Patients were stratified into low-risk, medium-risk, and high-risk groups based on HERNIAscore. A revised HERNIAscore was calculated with the addition of earlier abdominal operation as a categorical variable. Cox regression of incisional hernia with stratification by risk class was performed. Incidence rates of clinical VIH formation within each risk class were also calculated. Two hundred and forty-seven patents were enrolled. On Cox regression, in addition to the 3 variables of the HERNIAscore (BMI, COPD, and incision length), earlier abdominal operation was also predictive of VIH. The revised HERNIAscore demonstrated improved predictive accuracy for clinical VIH. Although the original HERNIAscore effectively stratified the risk of an incisional radiographic VIH developing, the revised HERNIAscore provided a statistically significant stratification for both clinical and radiographic VIHs in this patient cohort. We have externally validated and improved the HERNIAscore. The revised HERNIAscore uses BMI, incision length, COPD, and earlier abdominal operation to predict risk of postoperative incisional hernia. Future research should assess methods to prevent incisional hernias in moderate-to-high risk patients. Copyright © 2017 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  2. External Validation of the Acoustic Voice Quality Index Version 03.01 With Extended Representativity.

    Science.gov (United States)

    Barsties, Ben; Maryn, Youri

    2016-07-01

    The Acoustic Voice Quality Index (AVQI) is an objective method to quantify the severity of overall voice quality in concatenated continuous speech and sustained phonation segments. Recently, AVQI was successfully modified to be more representative and ecologically valid because the internal consistency of AVQI was balanced out through equal proportion of the 2 speech types. The present investigation aims to explore its external validation in a large data set. An expert panel of 12 speech-language therapists rated the voice quality of 1058 concatenated voice samples varying from normophonia to severe dysphonia. The Spearman rank-order correlation coefficients (r) were used to measure concurrent validity. The AVQI's diagnostic accuracy was evaluated with several estimates of its receiver operating characteristics (ROC). Finally, 8 of the 12 experts were chosen because of reliability criteria. A strong correlation was identified between AVQI and auditoryperceptual rating (r = 0.815, P = .000). It indicated that 66.4% of the auditory-perceptual rating's variation was explained by AVQI. Additionally, the ROC results showed again the best diagnostic outcome at a threshold of AVQI = 2.43. This study highlights external validation and diagnostic precision of the AVQI version 03.01 as a robust and ecologically valid measurement to objectify voice quality. © The Author(s) 2016.

  3. Frequency and time domain analysis of an external cavity laser with strong filtered optical feedback

    DEFF Research Database (Denmark)

    Detoma, Enrico; Tromborg, Bjarne; Montrosset, Ivo

    The stability properties of an external cavity laser with strong grating-filtered optical feedback to an anti-reflection coated facet are studied with a general frequency domain model. The model takes into account non-linear effects like four wave mixing and gain compression. A small......-signal analysis in the frequency domain allows a calculation of the range of operation without mode hopping around the grating reflectivity peak. This region should be as large as possible for proper operation of the tunable laser source. The analysis shows this stabilizing effect of mode coupling and gain...

  4. Experimental validation of a radio frequency photogun as external electron

    NARCIS (Netherlands)

    Stragier, X.F.D.; Luiten, O.J.; Geer, van der S.B.; Wiel, van der M.J.

    2011-01-01

    A purpose-built RF-photogun as external electron injector for a laser wakefield accelerator has been thoroughly tested. Different properties of the RF-photogun have been measured such as energy, energy spread and transverse emittance. The focus of this study is the investigation of the smallest

  5. The Internal, External, and Diagnostic Validity of Sluggish Cognitive Tempo: A Meta-Analysis and Critical Review

    Science.gov (United States)

    Becker, Stephen P.; Leopold, Daniel R.; Burns, G. Leonard; Jarrett, Matthew A.; Langberg, Joshua M.; Marshall, Stephen A.; McBurnett, Keith; Waschbusch, Daniel A.; Willcutt, Erik G.

    2015-01-01

    Objective To conduct the first meta-analysis evaluating the internal and external validity of the sluggish cognitive tempo (SCT) construct as related to or distinct from attention-deficit/hyperactivity disorder (ADHD) and as associated with functional impairment and neuropsychological functioning. Method Electronic databases were searched through September 2015 for studies examining the factor structure and/or correlates of SCT in children or adults. The search procedures identified 73 papers. The core SCT behaviors included across studies, as well as factor loadings and reliability estimates, were reviewed to evaluate internal validity. Pooled correlation effect sizes using random effects models were used to evaluate SCT in relation to external validity domains (i.e., demographics, other psychopathologies, functional impairment, and neuropsychological functioning). Results Strong support was found for the internal validity of the SCT construct. Specifically, across factor analytic studies including over 19,000 individuals, 13 SCT items loaded consistently on an SCT factor as opposed to an ADHD factor. Findings also support the reliability (i.e., internal consistency, test-retest reliability, inter-rater reliability) of SCT. In terms of external validity, there is some indication that SCT may increase with age (r = 0.11) and be associated with lower socioeconomic status (r = 0.10). Modest (potentially negligible) support was found for SCT symptoms being higher in males than females in children (r = 0.05) but not adults. SCT is more strongly associated with ADHD inattention (r = 0.63 in children, r = 0.72 in adults) than with ADHD hyperactivity-impulsivity (r = 0.32 in children, r = 0.46 in adults), and it likewise appears that SCT is more strongly associated with internalizing symptoms than with externalizing symptoms. SCT is associated with significant global, social, and academic impairment (rs = 0.38–0.44). Effects for neuropsychological functioning are mixed

  6. External Validity in the Study of Human Development: Theoretical and Methodological Issues

    Science.gov (United States)

    Hultsch, David F.; Hickey, Tom

    1978-01-01

    An examination of the concept of external validity from two theoretical perspectives: a traditional mechanistic approach and a dialectical organismic approach. Examines the theoretical and methodological implications of these perspectives. (BD)

  7. External review and validation of the Swedish national inpatient register

    Directory of Open Access Journals (Sweden)

    Kim Jeong-Lim

    2011-06-01

    Full Text Available Abstract Background The Swedish National Inpatient Register (IPR, also called the Hospital Discharge Register, is a principal source of data for numerous research projects. The IPR is part of the National Patient Register. The Swedish IPR was launched in 1964 (psychiatric diagnoses from 1973 but complete coverage did not begin until 1987. Currently, more than 99% of all somatic (including surgery and psychiatric hospital discharges are registered in the IPR. A previous validation of the IPR by the National Board of Health and Welfare showed that 85-95% of all diagnoses in the IPR are valid. The current paper describes the history, structure, coverage and quality of the Swedish IPR. Methods and results In January 2010, we searched the medical databases, Medline and HighWire, using the search algorithm "validat* (inpatient or hospital discharge Sweden". We also contacted 218 members of the Swedish Society of Epidemiology and an additional 201 medical researchers to identify papers that had validated the IPR. In total, 132 papers were reviewed. The positive predictive value (PPV was found to differ between diagnoses in the IPR, but is generally 85-95%. Conclusions In conclusion, the validity of the Swedish IPR is high for many but not all diagnoses. The long follow-up makes the register particularly suitable for large-scale population-based research, but for certain research areas the use of other health registers, such as the Swedish Cancer Register, may be more suitable.

  8. Renormalization of quantum electrodynamics in an arbitrarily strong time independent external field. [Perturbation theory

    Energy Technology Data Exchange (ETDEWEB)

    Dosch, H G [Heidelberg Univ. (F.R. Germany). Inst. fuer Theoretische Physik; Mueller, V F [Trier-Kaiserslautern Univ., Kaiserslautern (F.R. Germany). Fachbereich Physik

    1975-01-01

    Extending the inductive renormalization procedure of Epstein and Glaser which is essentially based on locality, we show that quantum electrodynamics in an external time independent electromagnetic field has a renormalizable formal perturbation expansion. The interaction involving the quantized radiation field but not the action of the external field is treated by perturbation theory. It turns out that vacuum polarization is undetermined in the framework of such a theory.

  9. External Validity and Model Validity: A Conceptual Approach for Systematic Review Methodology

    Directory of Open Access Journals (Sweden)

    Raheleh Khorsan

    2014-01-01

    Full Text Available Background. Evidence rankings do not consider equally internal (IV, external (EV, and model validity (MV for clinical studies including complementary and alternative medicine/integrative health care (CAM/IHC research. This paper describe this model and offers an EV assessment tool (EVAT© for weighing studies according to EV and MV in addition to IV. Methods. An abbreviated systematic review methodology was employed to search, assemble, and evaluate the literature that has been published on EV/MV criteria. Standard databases were searched for keywords relating to EV, MV, and bias-scoring from inception to Jan 2013. Tools identified and concepts described were pooled to assemble a robust tool for evaluating these quality criteria. Results. This study assembled a streamlined, objective tool to incorporate for the evaluation of quality of EV/MV research that is more sensitive to CAM/IHC research. Conclusion. Improved reporting on EV can help produce and provide information that will help guide policy makers, public health researchers, and other scientists in their selection, development, and improvement in their research-tested intervention. Overall, clinical studies with high EV have the potential to provide the most useful information about “real-world” consequences of health interventions. It is hoped that this novel tool which considers IV, EV, and MV on equal footing will better guide clinical decision making.

  10. The Complex Way to Laser Diode Spectra: Example of an External Cavity Laser With Strong Optical Feedback

    DEFF Research Database (Denmark)

    Detoma, Enrico; Tromborg, Bjarne; Montrosset, Ivo

    2005-01-01

    An external cavity laser with strong grating-filtered feedback to an antireflection-coated facet is studied with a time-domain integral equation for the electric field, which reproduces the modes of the oscillation condition as steady-state solutions. For each mode, the stability and spectral...... to simulate the large signal time evolution after start from unstable modes....

  11. External validation of a clinical scoring system for the risk of gestational diabetes mellitus

    NARCIS (Netherlands)

    van Leeuwen, M.; Opmeer, B. C.; Zweers, E. J. K.; van Ballegooie, E.; ter Brugge, H. G.; de Valk, H. W.; Visser, G. H. A.; Mol, B. W. J.

    Aim: A prediction rule for gestational diabetes mellitus (GDM) could be helpful in early detection and increased efficiency of screening. A prediction rule by means of a clinical scoring system is available, but has never been validated externally. The aim of this study was to validate the scoring

  12. External K+ dependence of strong inward rectifier K+ channel conductance is caused not by K+ but by competitive pore blockade by external Na.

    Science.gov (United States)

    Ishihara, Keiko

    2018-06-15

    Strong inward rectifier K + (sKir) channels determine the membrane potentials of many types of excitable and nonexcitable cells, most notably the resting potentials of cardiac myocytes. They show little outward current during membrane depolarization (i.e., strong inward rectification) because of the channel blockade by cytoplasmic polyamines, which depends on the deviation of the membrane potential from the K + equilibrium potential ( V - E K ) when the extracellular K + concentration ([K + ] out ) is changed. Because their open - channel conductance is apparently proportional to the "square root" of [K + ] out , increases/decreases in [K + ] out enhance/diminish outward currents through sKir channels at membrane potentials near their reversal potential, which also affects, for example, the repolarization and action-potential duration of cardiac myocytes. Despite its importance, however, the mechanism underlying the [K + ] out dependence of the open sKir channel conductance has remained elusive. By studying Kir2.1, the canonical member of the sKir channel family, we first show that the outward currents of Kir2.1 are observed under the external K + -free condition when its inward rectification is reduced and that the complete inhibition of the currents at 0 [K + ] out results solely from pore blockade caused by the polyamines. Moreover, the noted square-root proportionality of the open sKir channel conductance to [K + ] out is mediated by the pore blockade by the external Na + , which is competitive with the external K + Our results show that external K + itself does not activate or facilitate K + permeation through the open sKir channel to mediate the apparent external K + dependence of its open channel conductance. The paradoxical increase/decrease in outward sKir channel currents during alternations in [K + ] out , which is physiologically relevant, is caused by competition from impermeant extracellular Na . © 2018 Ishihara.

  13. Extension of the Nambu-Jona-Lasinio model predictions at high temperatures and strong external magnetic field

    International Nuclear Information System (INIS)

    Gomes, Karina P.; Farias, R.L.S.; Pinto, M.B.; Krein, G.

    2013-01-01

    Full text: Recently much attention is dedicated to understand the effects of an external magnetic field on the QCD phase diagram. Actually there is a contradiction in the literature: while effective models of QCD like the Nambu-Jona- Lasinio model (NJL) and linear sigma model predict an increase of the critical temperature of chiral symmetry restoration a function of the magnetic field, recent lattice results shows the opposite behavior. The NJL model is nonrenormalizable; then the high momentum part of the model has to be regularized in a phenomenological way. The common practice is to regularize the divergent loop amplitudes with a three-dimensional momentum cutoff, which also sets the energy-momentum scale for the validity of the model. That is, the model cannot be used for studying phenomena involving momenta running in loops larger than the cutoff. In particular, the model cannot be used to study quark matter at high densities. One of the symptoms of this problem is the prediction of vanishing superconducting gaps at high baryon densities, a feature of the model that is solely caused by the use of a regularizing momentum cutoff of the divergent vacuum and also in finite loop integrals. In a renormalizable theory all the dependence on the cutoff can be removed in favor of running physical parameters, like the coupling constants of QED and QCD. The running is given by the renormalization group equations of the theory and is controlled by an energy scale that is adjusted to the scale of the experimental conditions under consideration. In a recent publication, Casalbuoni et al. have introduced the concept of a running coupling constant for the NJL model to extend the applicability of the model to high density. Their arguments are based on making the cutoff density dependent, using an analogy with the natural cutoff of the Debye frequency of phonon oscillations in an ordinary solid. In the present work we follow such an approach introducing a magnetic field

  14. Pragmatic controlled clinical trials in primary care: the struggle between external and internal validity

    Directory of Open Access Journals (Sweden)

    Birtwhistle Richard

    2003-12-01

    Full Text Available Abstract Background Controlled clinical trials of health care interventions are either explanatory or pragmatic. Explanatory trials test whether an intervention is efficacious; that is, whether it can have a beneficial effect in an ideal situation. Pragmatic trials measure effectiveness; they measure the degree of beneficial effect in real clinical practice. In pragmatic trials, a balance between external validity (generalizability of the results and internal validity (reliability or accuracy of the results needs to be achieved. The explanatory trial seeks to maximize the internal validity by assuring rigorous control of all variables other than the intervention. The pragmatic trial seeks to maximize external validity to ensure that the results can be generalized. However the danger of pragmatic trials is that internal validity may be overly compromised in the effort to ensure generalizability. We are conducting two pragmatic randomized controlled trials on interventions in the management of hypertension in primary care. We describe the design of the trials and the steps taken to deal with the competing demands of external and internal validity. Discussion External validity is maximized by having few exclusion criteria and by allowing flexibility in the interpretation of the intervention and in management decisions. Internal validity is maximized by decreasing contamination bias through cluster randomization, and decreasing observer and assessment bias, in these non-blinded trials, through baseline data collection prior to randomization, automating the outcomes assessment with 24 hour ambulatory blood pressure monitors, and blinding the data analysis. Summary Clinical trials conducted in community practices present investigators with difficult methodological choices related to maintaining a balance between internal validity (reliability of the results and external validity (generalizability. The attempt to achieve methodological purity can

  15. External validation and comparison of three pediatric clinical dehydration scales.

    Directory of Open Access Journals (Sweden)

    Joshua Jauregui

    Full Text Available OBJECTIVE: To prospectively validate three popular clinical dehydration scales and overall physician gestalt in children with vomiting or diarrhea relative to the criterion standard of percent weight change with rehydration. METHODS: We prospectively enrolled a non-consecutive cohort of children ≤ 18 years of age with an acute episode of diarrhea or vomiting. Patient weight, clinical scale variables and physician clinical impression, or gestalt, were recorded before and after fluid resuscitation in the emergency department and upon hospital discharge. The percent weight change from presentation to discharge was used to calculate the degree of dehydration, with a weight change of ≥ 5% considered significant dehydration. Receiver operating characteristics (ROC curves were constructed for each of the three clinical scales and physician gestalt. Sensitivity and specificity were calculated based on the best cut-points of the ROC curve. RESULTS: We approached 209 patients, and of those, 148 were enrolled and 113 patients had complete data for analysis. Of these, 10.6% had significant dehydration based on our criterion standard. The Clinical Dehydration Scale (CDS and Gorelick scales both had an area under the ROC curve (AUC statistically different from the reference line with AUCs of 0.72 (95% CI 0.60, 0.84 and 0.71 (95% CI 0.57, 0.85 respectively. The World Health Organization (WHO scale and physician gestalt had AUCs of 0.61 (95% CI 0.45, 0.77 and 0.61 (0.44, 0.78 respectively, which were not statistically significant. CONCLUSION: The Gorelick scale and Clinical Dehydration Scale were fair predictors of dehydration in children with diarrhea or vomiting. The World Health Organization scale and physician gestalt were not helpful predictors of dehydration in our cohort.

  16. External validation and comparison of three pediatric clinical dehydration scales.

    Science.gov (United States)

    Jauregui, Joshua; Nelson, Daniel; Choo, Esther; Stearns, Branden; Levine, Adam C; Liebmann, Otto; Shah, Sachita P

    2014-01-01

    To prospectively validate three popular clinical dehydration scales and overall physician gestalt in children with vomiting or diarrhea relative to the criterion standard of percent weight change with rehydration. We prospectively enrolled a non-consecutive cohort of children ≤ 18 years of age with an acute episode of diarrhea or vomiting. Patient weight, clinical scale variables and physician clinical impression, or gestalt, were recorded before and after fluid resuscitation in the emergency department and upon hospital discharge. The percent weight change from presentation to discharge was used to calculate the degree of dehydration, with a weight change of ≥ 5% considered significant dehydration. Receiver operating characteristics (ROC) curves were constructed for each of the three clinical scales and physician gestalt. Sensitivity and specificity were calculated based on the best cut-points of the ROC curve. We approached 209 patients, and of those, 148 were enrolled and 113 patients had complete data for analysis. Of these, 10.6% had significant dehydration based on our criterion standard. The Clinical Dehydration Scale (CDS) and Gorelick scales both had an area under the ROC curve (AUC) statistically different from the reference line with AUCs of 0.72 (95% CI 0.60, 0.84) and 0.71 (95% CI 0.57, 0.85) respectively. The World Health Organization (WHO) scale and physician gestalt had AUCs of 0.61 (95% CI 0.45, 0.77) and 0.61 (0.44, 0.78) respectively, which were not statistically significant. The Gorelick scale and Clinical Dehydration Scale were fair predictors of dehydration in children with diarrhea or vomiting. The World Health Organization scale and physician gestalt were not helpful predictors of dehydration in our cohort.

  17. Secular Orbit Evolution in Systems with a Strong External Perturber—A Simple and Accurate Model

    Energy Technology Data Exchange (ETDEWEB)

    Andrade-Ines, Eduardo [Institute de Mécanique Céleste et des Calcul des Éphémérides—Observatoire de Paris, 77 Avenue Denfert Rochereau, F-75014 Paris (France); Eggl, Siegfried, E-mail: eandrade.ines@gmail.com, E-mail: siegfried.eggl@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, 91109 Pasadena, CA (United States)

    2017-04-01

    We present a semi-analytical correction to the seminal solution for the secular motion of a planet’s orbit under gravitational influence of an external perturber derived by Heppenheimer. A comparison between analytical predictions and numerical simulations allows us to determine corrective factors for the secular frequency and forced eccentricity in the coplanar restricted three-body problem. The correction is given in the form of a polynomial function of the system’s parameters that can be applied to first-order forced eccentricity and secular frequency estimates. The resulting secular equations are simple, straight forward to use, and improve the fidelity of Heppenheimers solution well beyond higher-order models. The quality and convergence of the corrected secular equations are tested for a wide range of parameters and limits of its applicability are given.

  18. External validation of the ability of the DRAGON score to predict outcome after thrombolysis treatment

    DEFF Research Database (Denmark)

    Ovesen, Christian Aavang; Christensen, Anders; Nielsen, J K

    2013-01-01

    Easy-to-perform and valid assessment scales for the effect of thrombolysis are essential in hyperacute stroke settings. Because of this we performed an external validation of the DRAGON scale proposed by Strbian et al. in a Danish cohort. All patients treated with intravenous recombinant plasmino......Easy-to-perform and valid assessment scales for the effect of thrombolysis are essential in hyperacute stroke settings. Because of this we performed an external validation of the DRAGON scale proposed by Strbian et al. in a Danish cohort. All patients treated with intravenous recombinant...... and their modified Rankin Scale (mRS) was assessed after 3 months. Three hundred and three patients were included in the analysis. The DRAGON scale proved to have a good discriminative ability for predicting highly unfavourable outcome (mRS 5-6) (area under the curve-receiver operating characteristic [AUC-ROC]: 0...

  19. External validation of the NOBLADS score, a risk scoring system for severe acute lower gastrointestinal bleeding.

    Directory of Open Access Journals (Sweden)

    Tomonori Aoki

    Full Text Available We aimed to evaluate the generalizability of NOBLADS, a severe lower gastrointestinal bleeding (LGIB prediction model which we had previously derived when working at a different institution, using an external validation cohort. NOBLADS comprises the following factors: non-steroidal anti-inflammatory drug use, no diarrhea, no abdominal tenderness, blood pressure ≤ 100 mmHg, antiplatelet drug use, albumin < 3.0 g/dL, disease score ≥ 2, and syncope.We retrospectively analyzed 511 patients emergently hospitalized for acute LGIB at the University of Tokyo Hospital, from January 2009 to August 2016. The areas under the receiver operating characteristic curves (ROCs-AUCs for severe bleeding (continuous and/or recurrent bleeding were compared between the original derivation cohort and the external validation cohort.Severe LGIB occurred in 44% of patients. Several clinical factors were significantly different between the external and derivation cohorts (p < 0.05, including background, laboratory data, NOBLADS scores, and diagnosis. The NOBLADS score predicted the severity of LGIB with an AUC value of 0.74 in the external validation cohort and one of 0.77 in the derivation cohort. In the external validation cohort, the score predicted the risk for blood transfusion need (AUC, 0.71, but was not adequate for predicting intervention need (AUC, 0.54. The in-hospital mortality rate was higher in patients with a score ≥ 5 than in those with a score < 5 (AUC, 0.83.Although the external validation cohort clinically differed from the derivation cohort in many ways, we confirmed the moderately high generalizability of NOBLADS, a clinical risk score for severe LGIB. Appropriate triage using this score may support early decision-making in various hospitals.

  20. Supercritical Nonlinear Vibration of a Fluid-Conveying Pipe Subjected to a Strong External Excitation

    Directory of Open Access Journals (Sweden)

    Yan-Lei Zhang

    2016-01-01

    Full Text Available Nonlinear vibration of a fluid-conveying pipe subjected to a transverse external harmonic excitation is investigated in the case with two-to-one internal resonance. The excitation amplitude is in the same magnitude of the transverse displacement. The fluid in the pipes flows in the speed larger than the critical speed so that the straight configuration becomes an unstable equilibrium and two curved configurations bifurcate as stable equilibriums. The motion measured from each of curved equilibrium configurations is governed by a nonlinear integro-partial-differential equation with variable coefficients. The Galerkin method is employed to discretize the governing equation into a gyroscopic system consisting of a set of coupled nonlinear ordinary differential equations. The method of multiple scales is applied to analyze approximately the gyroscopic system. A set of first-order ordinary differential equations governing the modulations of the amplitude and the phase are derived via the method. In the supercritical regime, the subharmonic, superharmonic, and combination resonances are examined in the presence of the 2 : 1 internal resonance. The steady-state responses and their stabilities are determined. The various jump phenomena in the amplitude-frequency response curves are demonstrated. The effects of the viscosity, the excitation amplitude, the nonlinearity, and the flow speed are observed. The analytical results are supported by the numerical integration.

  1. Measurement of dipole-moment in atomic transitions under strong external magnetic field

    International Nuclear Information System (INIS)

    Nittoh, Koichi; Kuwako, Akira; Ikehara, Tadashi; Yoshida, Tadashi; Watanabe, Takasi; Yoguchi, Itaru; Suzuki, Kazuhiro.

    1996-01-01

    Obtaining an accurate value of the electric dipole moment μ is essential in the fields of laser application technologies. A direct way of measuring the electric dipole moment μ is to observe the Rabi-oscillation which manifests itself in the coherent photo-excitation behavior of atoms. In the case of the elements which have large angular momenta, identifying the Rabi-oscillation in their excitation behavior becomes rather difficult. We proposed an accurate and straightforward method of determining the electric-dipole moment μ between multi-fold degenerate levels. The point is to remove the degeneracy by applying an external magnetic field with the aid of the Zeeman effect and, then, to realize a degeneration free coherent excitation. As a result, we can observe the Rabi-oscillations explicitly in the excitation υs. laser-fluence curves. The present method provides a reliable basis of experimental determination of μ. As an example, we applied the present method to a transition to 0-17,362 cm -1 level in uranium and obtained the value μ=0.86±0.06 (Debye). (author)

  2. Supply Networks and Value Creation in High Innovation and Strong Network Externalities Industry

    Directory of Open Access Journals (Sweden)

    Fernando Claro Tomaselli

    2013-12-01

    Full Text Available The rapid developing product and service markets and developments in information technologies have accelerated growth in outsourcing of peripheral activities and critical business as well, enhancing the importance of network supply chain management. This paper analyzes the dynamics of supply chain management and the creation of value in an industry with strong network effects and constantly introduction of disruptive technologies, the videogame industry. This industry evolves at a high velocity, with a lifecycle of five to six years for consoles, which features a new generation of consoles, where new companies and technologies appear and disappear at each generation.

  3. Ehrenfest's theorem and the validity of the two-step model for strong-field ionization

    DEFF Research Database (Denmark)

    Shvetsov-Shilovskiy, Nikolay; Dimitrovski, Darko; Madsen, Lars Bojer

    By comparison with the solution of the time-dependent Schrodinger equation we explore the validity of the two-step semiclassical model for strong-field ionization in elliptically polarized laser pulses. We find that the discrepancy between the two-step model and the quantum theory correlates...

  4. The Main Concept Analysis in Cantonese Aphasic Oral Discourse: External Validation and Monitoring Chronic Aphasia

    Science.gov (United States)

    Kong, Anthony Pak-Hin

    2011-01-01

    Purpose: The 1st aim of this study was to further establish the external validity of the main concept (MC) analysis by examining its relationship with the Cantonese Linguistic Communication Measure (CLCM; Kong, 2006; Kong & Law, 2004)--an established quantitative system for narrative production--and the Cantonese version of the Western Aphasia…

  5. Analysis of internal and external validity criteria for a computerized visual search task: A pilot study.

    Science.gov (United States)

    Richard's, María M; Introzzi, Isabel; Zamora, Eliana; Vernucci, Santiago

    2017-01-01

    Inhibition is one of the main executive functions, because of its fundamental role in cognitive and social development. Given the importance of reliable and computerized measurements to assessment inhibitory performance, this research intends to analyze the internal and external criteria of validity of a computerized conjunction search task, to evaluate the role of perceptual inhibition. A sample of 41 children (21 females and 20 males), aged between 6 and 11 years old (M = 8.49, SD = 1.47), intentionally selected from a private management school of Mar del Plata (Argentina), middle socio-economic level were assessed. The Conjunction Search Task from the TAC Battery, Coding and Symbol Search tasks from Wechsler Intelligence Scale for Children were used. Overall, results allow us to confirm that the perceptual inhibition task form TAC presents solid rates of internal and external validity that make a valid measurement instrument of this process.

  6. External validation of models predicting the individual risk of metachronous peritoneal carcinomatosis from colon and rectal cancer.

    Science.gov (United States)

    Segelman, J; Akre, O; Gustafsson, U O; Bottai, M; Martling, A

    2016-04-01

    To externally validate previously published predictive models of the risk of developing metachronous peritoneal carcinomatosis (PC) after resection of nonmetastatic colon or rectal cancer and to update the predictive model for colon cancer by adding new prognostic predictors. Data from all patients with Stage I-III colorectal cancer identified from a population-based database in Stockholm between 2008 and 2010 were used. We assessed the concordance between the predicted and observed probabilities of PC and utilized proportional-hazard regression to update the predictive model for colon cancer. When applied to the new validation dataset (n = 2011), the colon and rectal cancer risk-score models predicted metachronous PC with a concordance index of 79% and 67%, respectively. After adding the subclasses of pT3 and pT4 stage and mucinous tumour to the colon cancer model, the concordance index increased to 82%. In validation of external and recent cohorts, the predictive accuracy was strong in colon cancer and moderate in rectal cancer patients. The model can be used to identify high-risk patients for planned second-look laparoscopy/laparotomy for possible subsequent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. Colorectal Disease © 2015 The Association of Coloproctology of Great Britain and Ireland.

  7. Prediction of prostate cancer in unscreened men: external validation of a risk calculator.

    Science.gov (United States)

    van Vugt, Heidi A; Roobol, Monique J; Kranse, Ries; Määttänen, Liisa; Finne, Patrik; Hugosson, Jonas; Bangma, Chris H; Schröder, Fritz H; Steyerberg, Ewout W

    2011-04-01

    Prediction models need external validation to assess their value beyond the setting where the model was derived from. To assess the external validity of the European Randomized study of Screening for Prostate Cancer (ERSPC) risk calculator (www.prostatecancer-riskcalculator.com) for the probability of having a positive prostate biopsy (P(posb)). The ERSPC risk calculator was based on data of the initial screening round of the ERSPC section Rotterdam and validated in 1825 and 531 men biopsied at the initial screening round in the Finnish and Swedish sections of the ERSPC respectively. P(posb) was calculated using serum prostate specific antigen (PSA), outcome of digital rectal examination (DRE), transrectal ultrasound and ultrasound assessed prostate volume. The external validity was assessed for the presence of cancer at biopsy by calibration (agreement between observed and predicted outcomes), discrimination (separation of those with and without cancer), and decision curves (for clinical usefulness). Prostate cancer was detected in 469 men (26%) of the Finnish cohort and in 124 men (23%) of the Swedish cohort. Systematic miscalibration was present in both cohorts (mean predicted probability 34% versus 26% observed, and 29% versus 23% observed, both pscreened men, but overestimated the risk of a positive biopsy. Further research is necessary to assess the performance and applicability of the ERSPC risk calculator when a clinical setting is considered rather than a screening setting. Copyright © 2010 Elsevier Ltd. All rights reserved.

  8. External validation of the Cairns Prediction Model (CPM) to predict conversion from laparoscopic to open cholecystectomy.

    Science.gov (United States)

    Hu, Alan Shiun Yew; Donohue, Peter O'; Gunnarsson, Ronny K; de Costa, Alan

    2018-03-14

    Valid and user-friendly prediction models for conversion to open cholecystectomy allow for proper planning prior to surgery. The Cairns Prediction Model (CPM) has been in use clinically in the original study site for the past three years, but has not been tested at other sites. A retrospective, single-centred study collected ultrasonic measurements and clinical variables alongside with conversion status from consecutive patients who underwent laparoscopic cholecystectomy from 2013 to 2016 in The Townsville Hospital, North Queensland, Australia. An area under the curve (AUC) was calculated to externally validate of the CPM. Conversion was necessary in 43 (4.2%) out of 1035 patients. External validation showed an area under the curve of 0.87 (95% CI 0.82-0.93, p = 1.1 × 10 -14 ). In comparison with most previously published models, which have an AUC of approximately 0.80 or less, the CPM has the highest AUC of all published prediction models both for internal and external validation. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

  9. External validation of multivariable prediction models: a systematic review of methodological conduct and reporting

    Science.gov (United States)

    2014-01-01

    Background Before considering whether to use a multivariable (diagnostic or prognostic) prediction model, it is essential that its performance be evaluated in data that were not used to develop the model (referred to as external validation). We critically appraised the methodological conduct and reporting of external validation studies of multivariable prediction models. Methods We conducted a systematic review of articles describing some form of external validation of one or more multivariable prediction models indexed in PubMed core clinical journals published in 2010. Study data were extracted in duplicate on design, sample size, handling of missing data, reference to the original study developing the prediction models and predictive performance measures. Results 11,826 articles were identified and 78 were included for full review, which described the evaluation of 120 prediction models. in participant data that were not used to develop the model. Thirty-three articles described both the development of a prediction model and an evaluation of its performance on a separate dataset, and 45 articles described only the evaluation of an existing published prediction model on another dataset. Fifty-seven percent of the prediction models were presented and evaluated as simplified scoring systems. Sixteen percent of articles failed to report the number of outcome events in the validation datasets. Fifty-four percent of studies made no explicit mention of missing data. Sixty-seven percent did not report evaluating model calibration whilst most studies evaluated model discrimination. It was often unclear whether the reported performance measures were for the full regression model or for the simplified models. Conclusions The vast majority of studies describing some form of external validation of a multivariable prediction model were poorly reported with key details frequently not presented. The validation studies were characterised by poor design, inappropriate handling

  10. Large-scale external validation and comparison of prognostic models: an application to chronic obstructive pulmonary disease

    NARCIS (Netherlands)

    Guerra, Beniamino; Haile, Sarah R.; Lamprecht, Bernd; Ramírez, Ana S.; Martinez-Camblor, Pablo; Kaiser, Bernhard; Alfageme, Inmaculada; Almagro, Pere; Casanova, Ciro; Esteban-González, Cristóbal; Soler-Cataluña, Juan J.; de-Torres, Juan P.; Miravitlles, Marc; Celli, Bartolome R.; Marin, Jose M.; ter Riet, Gerben; Sobradillo, Patricia; Lange, Peter; Garcia-Aymerich, Judith; Antó, Josep M.; Turner, Alice M.; Han, MeiLan K.; Langhammer, Arnulf; Leivseth, Linda; Bakke, Per; Johannessen, Ane; Oga, Toru; Cosio, Borja; Ancochea-Bermúdez, Julio; Echazarreta, Andres; Roche, Nicolas; Burgel, Pierre-Régis; Sin, Don D.; Soriano, Joan B.; Puhan, Milo A.

    2018-01-01

    External validations and comparisons of prognostic models or scores are a prerequisite for their use in routine clinical care but are lacking in most medical fields including chronic obstructive pulmonary disease (COPD). Our aim was to externally validate and concurrently compare prognostic scores

  11. Estimating mortality from external causes using data from retrospective surveys: A validation study in Niakhar (Senegal

    Directory of Open Access Journals (Sweden)

    Gilles Pison

    2018-03-01

    Full Text Available Background: In low- and middle-income countries (LMICs, data on causes of death is often inaccurate or incomplete. In this paper, we test whether adding a few questions about injuries and accidents to mortality questionnaires used in representative household surveys would yield accurate estimates of the extent of mortality due to external causes (accidents, homicides, or suicides. Methods: We conduct a validation study in Niakhar (Senegal, during which we compare reported survey data to high-quality prospective records of deaths collected by a health and demographic surveillance system (HDSS. Results: Survey respondents more frequently list the deaths of their adult siblings who die of external causes than the deaths of those who die from other causes. The specificity of survey data is high, but sensitivity is low. Among reported deaths, less than 60Š of the deaths classified as due to external causes by the HDSS are also classified as such by survey respondents. Survey respondents better report deaths due to road-traffic accidents than deaths from suicides and homicides. Conclusions: Asking questions about deaths resulting from injuries and accidents during surveys might help measure mortality from external causes in LMICs, but the resulting data displays systematic bias in a rural population of Senegal. Future studies should 1 investigate whether similar biases also apply in other settings and 2 test new methods to further improve the accuracy of survey data on mortality from external causes. Contribution: This study helps strengthen the monitoring of sustainable development targets in LMICs by validating a simple approach for the measurement of mortality from external causes.

  12. External Validation of Prediction Models for Pneumonia in Primary Care Patients with Lower Respiratory Tract Infection

    DEFF Research Database (Denmark)

    Schierenberg, Alwin; Minnaard, Margaretha C; Hopstaken, Rogier M

    2016-01-01

    BACKGROUND: Pneumonia remains difficult to diagnose in primary care. Prediction models based on signs and symptoms (S&S) serve to minimize the diagnostic uncertainty. External validation of these models is essential before implementation into routine practice. In this study all published S&S mode...... discriminative accuracy coupled with reasonable to good calibration across the IPD of different study populations. This model is therefore the main candidate for primary care use....

  13. Achieving external validity in home advantage research: generalizing crowd noise effects

    Directory of Open Access Journals (Sweden)

    Tony D Myers

    2014-06-01

    Full Text Available Different factors have been postulated to explain the home advantage phenomenon in sport. One plausible explanation investigated has been the influence of a partisan home crowd on sports officials’ decisions. Different types of studies have tested the crowd influence hypothesis including purposefully designed experiments. However, while experimental studies investigating crowd influences have high levels of internal validity, they suffer from a lack of external validity; decision-making in a laboratory setting bearing little resemblance to decision-making in live sports settings. This focused review initially considers threats to external validity in applied and theoretical experimental research. Discussing how such threats can be addressed using representative design by focusing on a recently published study that arguably provides the first experimental evidence of the impact of live crowd noise on officials in sport. The findings of this controlled experiment conducted in a real tournament setting offer some confirmation of the validity of laboratory experimental studies in the area. Finally directions for future research and the future conduct of crowd noise studies are discussed.

  14. Review and evaluation of performance measures for survival prediction models in external validation settings

    Directory of Open Access Journals (Sweden)

    M. Shafiqur Rahman

    2017-04-01

    Full Text Available Abstract Background When developing a prediction model for survival data it is essential to validate its performance in external validation settings using appropriate performance measures. Although a number of such measures have been proposed, there is only limited guidance regarding their use in the context of model validation. This paper reviewed and evaluated a wide range of performance measures to provide some guidelines for their use in practice. Methods An extensive simulation study based on two clinical datasets was conducted to investigate the performance of the measures in external validation settings. Measures were selected from categories that assess the overall performance, discrimination and calibration of a survival prediction model. Some of these have been modified to allow their use with validation data, and a case study is provided to describe how these measures can be estimated in practice. The measures were evaluated with respect to their robustness to censoring and ease of interpretation. All measures are implemented, or are straightforward to implement, in statistical software. Results Most of the performance measures were reasonably robust to moderate levels of censoring. One exception was Harrell’s concordance measure which tended to increase as censoring increased. Conclusions We recommend that Uno’s concordance measure is used to quantify concordance when there are moderate levels of censoring. Alternatively, Gönen and Heller’s measure could be considered, especially if censoring is very high, but we suggest that the prediction model is re-calibrated first. We also recommend that Royston’s D is routinely reported to assess discrimination since it has an appealing interpretation. The calibration slope is useful for both internal and external validation settings and recommended to report routinely. Our recommendation would be to use any of the predictive accuracy measures and provide the corresponding predictive

  15. External validity of the Indonesian Wechsler Adult Intelligence Scale - Fourth edition (WAIS-IV-ID)

    NARCIS (Netherlands)

    Suwartono, C.; Hidajat, L.L.; Halim, M.S.; Hendriks, M.P.H.; Kessels, R.P.C.

    2016-01-01

    The Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV-ID) has been adapted and proved to be valid for its internal structure for Indonesian population. The same structure found as in the American WAIS-IV (WAIS-IV-US; Suwartono, Hendriks, Hidajat, Halim, & Kessels, 2015). Despite its strong

  16. Multicentre validation of IMRT pre-treatment verification: Comparison of in-house and external audit

    International Nuclear Information System (INIS)

    Jornet, Núria; Carrasco, Pablo; Beltrán, Mercè; Calvo, Juan Francisco; Escudé, Lluís; Hernández, Victor; Quera, Jaume; Sáez, Jordi

    2014-01-01

    Background and purpose: We performed a multicentre intercomparison of IMRT optimisation and dose planning and IMRT pre-treatment verification methods and results. The aims were to check consistency between dose plans and to validate whether in-house pre-treatment verification results agreed with those of an external audit. Materials and methods: Participating centres used two mock cases (prostate and head and neck) for the intercomparison and audit. Compliance to dosimetric goals and total number of MU per plan were collected. A simple quality index to compare the different plans was proposed. We compared gamma index pass rates using the centre’s equipment and methodology to those of an external audit. Results: While for the prostate case, all centres fulfilled the dosimetric goals and plan quality was homogeneous, that was not the case for the head and neck case. The number of MU did not correlate with the plan quality index. Pre-treatment verifications results of the external audit did not agree with those of the in-house measurements for two centres: being within tolerance for in-house measurements and unacceptable for the audit or the other way round. Conclusions: Although all plans fulfilled dosimetric constraints, plan quality is highly dependent on the planner expertise. External audits are an excellent tool to detect errors in IMRT implementation and cannot be replaced by intercomparison using results obtained by centres

  17. Development and external validation of a prognostic nomogram for metastatic uveal melanoma.

    Directory of Open Access Journals (Sweden)

    Sara Valpione

    Full Text Available Approximately 50% of patients with uveal melanoma (UM will develop metastatic disease, usually involving the liver. The outcome of metastatic UM (mUM is generally poor and no standard therapy has been established. Additionally, clinicians lack a validated prognostic tool to evaluate these patients. The aim of this work was to develop a reliable prognostic nomogram for clinicians.Two cohorts of mUM patients, from Veneto Oncology Institute (IOV (N=152 and Mayo Clinic (MC (N=102, were analyzed to develop and externally validate, a prognostic nomogram.The median survival of mUM was 17.2 months in the IOV cohort and 19.7 in the MC cohort. Percentage of liver involvement (HR 1.6, elevated levels of serum LDH (HR 1.6, and a WHO performance status=1 (HR 1.5 or 2-3 (HR 4.6 were associated with worse prognosis. Longer disease-free interval from diagnosis of UM to that of mUM conferred a survival advantage (HR 0.9. The nomogram had a concordance probability of 0.75 (SE .006 in the development dataset (IOV, and 0.80 (SE .009 in the external validation (MC. Nomogram predictions were well calibrated.The nomogram, which includes percentage of liver involvement, LDH levels, WHO performance status and disease free-interval accurately predicts the prognosis of mUM and could be useful for decision-making and risk stratification for clinical trials.

  18. Achieving external validity in home advantage research: generalizing crowd noise effects.

    Science.gov (United States)

    Myers, Tony D

    2014-01-01

    Different factors have been postulated to explain the home advantage phenomenon in sport. One plausible explanation investigated has been the influence of a partisan home crowd on sports officials' decisions. Different types of studies have tested the crowd influence hypothesis including purposefully designed experiments. However, while experimental studies investigating crowd influences have high levels of internal validity, they suffer from a lack of external validity; decision-making in a laboratory setting bearing little resemblance to decision-making in live sports settings. This focused review initially considers threats to external validity in applied and theoretical experimental research. Discussing how such threats can be addressed using representative design by focusing on a recently published study that arguably provides the first experimental evidence of the impact of live crowd noise on officials in sport. The findings of this controlled experiment conducted in a real tournament setting offer a level of confirmation of the findings of laboratory studies in the area. Finally directions for future research and the future conduct of crowd noise studies are discussed.

  19. When all children comprehend: increasing the external validity of narrative comprehension development research

    Science.gov (United States)

    Burris, Silas E.; Brown, Danielle D.

    2014-01-01

    Narratives, also called stories, can be found in conversations, children's play interactions, reading material, and television programs. From infancy to adulthood, narrative comprehension processes interpret events and inform our understanding of physical and social environments. These processes have been extensively studied to ascertain the multifaceted nature of narrative comprehension. From this research we know that three overlapping processes (i.e., knowledge integration, goal structure understanding, and causal inference generation) proposed by the constructionist paradigm are necessary for narrative comprehension, narrative comprehension has a predictive relationship with children's later reading performance, and comprehension processes are generalizable to other contexts. Much of the previous research has emphasized internal and predictive validity; thus, limiting the generalizability of previous findings. We are concerned these limitations may be excluding underrepresented populations from benefits and implications identified by early comprehension processes research. This review identifies gaps in extant literature regarding external validity and argues for increased emphasis on externally valid research. We highlight limited research on narrative comprehension processes in children from low-income and minority populations, and argue for changes in comprehension assessments. Specifically, we argue both on- and off-line assessments should be used across various narrative types (e.g., picture books, televised narratives) with traditionally underserved and underrepresented populations. We propose increasing the generalizability of narrative comprehension processes research can inform persistent reading achievement gaps, and have practical implications for how children learn from narratives. PMID:24659973

  20. Adapting social neuroscience measures for schizophrenia clinical trials, part 3: fathoming external validity.

    Science.gov (United States)

    Olbert, Charles M; Penn, David L; Kern, Robert S; Lee, Junghee; Horan, William P; Reise, Steven P; Ochsner, Kevin N; Marder, Stephen R; Green, Michael F

    2013-11-01

    It is unknown whether measures adapted from social neuroscience linked to specific neural systems will demonstrate relationships to external variables. Four paradigms adapted from social neuroscience were administered to 173 clinically stable outpatients with schizophrenia to determine their relationships to functionally meaningful variables and to investigate their incremental validity beyond standard measures of social and nonsocial cognition. The 4 paradigms included 2 that assess perception of nonverbal social and action cues (basic biological motion and emotion in biological motion) and 2 that involve higher level inferences about self and others' mental states (self-referential memory and empathic accuracy). Overall, social neuroscience paradigms showed significant relationships to functional capacity but weak relationships to community functioning; the paradigms also showed weak correlations to clinical symptoms. Evidence for incremental validity beyond standard measures of social and nonsocial cognition was mixed with additional predictive power shown for functional capacity but not community functioning. Of the newly adapted paradigms, the empathic accuracy task had the broadest external validity. These results underscore the difficulty of translating developments from neuroscience into clinically useful tasks with functional significance.

  1. When All Children Comprehend: Increasing the External Validity of Narrative Comprehension Development Research

    Directory of Open Access Journals (Sweden)

    Silas E. Burris

    2014-03-01

    Full Text Available Narratives, also called stories, can be found in conversations, children’s play interactions, reading material, and television programs. From infancy to adulthood, narrative comprehension processes interpret events and inform our understanding of physical and social environments. These processes have been extensively studied to ascertain the multifaceted nature of narrative comprehension. From this research we know that three overlapping processes (i.e., knowledge integration, goal structure understanding, and causal inference generation proposed by the constructionist paradigm are necessary for narrative comprehension, narrative comprehension has a predictive relationship with children’s later reading performance, and comprehension processes are generalizable to other contexts. Much of the previous research has emphasized internal and predictive validity; thus, limiting the generalizability of previous findings. We are concerned these limitations may be excluding underrepresented populations from benefits and implications identified by early comprehension processes research. This review identifies gaps in extant literature regarding external validity and argues for increased emphasis on externally valid research. We highlight limited research on narrative comprehension processes in children from low-income and minority populations, and argue for changes in comprehension assessments. Specifically, we argue both on- and off-line assessments should be used across various narrative types (e.g., picture books, televised narratives with traditionally underserved and underrepresented populations. We propose increasing the generalizability narrative comprehension processes research can inform persistent reading achievement gaps, and have practical implications for how children learn from narratives.

  2. Predicting Overall Survival After Stereotactic Ablative Radiation Therapy in Early-Stage Lung Cancer: Development and External Validation of the Amsterdam Prognostic Model

    Energy Technology Data Exchange (ETDEWEB)

    Louie, Alexander V., E-mail: Dr.alexlouie@gmail.com [Department of Radiation Oncology, VU University Medical Center, Amsterdam (Netherlands); Department of Radiation Oncology, London Regional Cancer Program, University of Western Ontario, London, Ontario (Canada); Department of Epidemiology, Harvard School of Public Health, Harvard University, Boston, Massachusetts (United States); Haasbeek, Cornelis J.A. [Department of Radiation Oncology, VU University Medical Center, Amsterdam (Netherlands); Mokhles, Sahar [Department of Cardio-Thoracic Surgery, Erasmus University Medical Center, Rotterdam (Netherlands); Rodrigues, George B. [Department of Radiation Oncology, London Regional Cancer Program, University of Western Ontario, London, Ontario (Canada); Stephans, Kevin L. [Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio (United States); Lagerwaard, Frank J. [Department of Radiation Oncology, VU University Medical Center, Amsterdam (Netherlands); Palma, David A. [Department of Radiation Oncology, London Regional Cancer Program, University of Western Ontario, London, Ontario (Canada); Videtic, Gregory M.M. [Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio (United States); Warner, Andrew [Department of Radiation Oncology, London Regional Cancer Program, University of Western Ontario, London, Ontario (Canada); Takkenberg, Johanna J.M. [Department of Cardio-Thoracic Surgery, Erasmus University Medical Center, Rotterdam (Netherlands); Reddy, Chandana A. [Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio (United States); Maat, Alex P.W.M. [Department of Cardio-Thoracic Surgery, Erasmus University Medical Center, Rotterdam (Netherlands); Woody, Neil M. [Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio (United States); Slotman, Ben J.; Senan, Suresh [Department of Radiation Oncology, VU University Medical Center, Amsterdam (Netherlands)

    2015-09-01

    Purpose: A prognostic model for 5-year overall survival (OS), consisting of recursive partitioning analysis (RPA) and a nomogram, was developed for patients with early-stage non-small cell lung cancer (ES-NSCLC) treated with stereotactic ablative radiation therapy (SABR). Methods and Materials: A primary dataset of 703 ES-NSCLC SABR patients was randomly divided into a training (67%) and an internal validation (33%) dataset. In the former group, 21 unique parameters consisting of patient, treatment, and tumor factors were entered into an RPA model to predict OS. Univariate and multivariate models were constructed for RPA-selected factors to evaluate their relationship with OS. A nomogram for OS was constructed based on factors significant in multivariate modeling and validated with calibration plots. Both the RPA and the nomogram were externally validated in independent surgical (n=193) and SABR (n=543) datasets. Results: RPA identified 2 distinct risk classes based on tumor diameter, age, World Health Organization performance status (PS) and Charlson comorbidity index. This RPA had moderate discrimination in SABR datasets (c-index range: 0.52-0.60) but was of limited value in the surgical validation cohort. The nomogram predicting OS included smoking history in addition to RPA-identified factors. In contrast to RPA, validation of the nomogram performed well in internal validation (r{sup 2}=0.97) and external SABR (r{sup 2}=0.79) and surgical cohorts (r{sup 2}=0.91). Conclusions: The Amsterdam prognostic model is the first externally validated prognostication tool for OS in ES-NSCLC treated with SABR available to individualize patient decision making. The nomogram retained strong performance across surgical and SABR external validation datasets. RPA performance was poor in surgical patients, suggesting that 2 different distinct patient populations are being treated with these 2 effective modalities.

  3. External gear pumps operating with non-Newtonian fluids: Modelling and experimental validation

    Science.gov (United States)

    Rituraj, Fnu; Vacca, Andrea

    2018-06-01

    External Gear Pumps are used in various industries to pump non-Newtonian viscoelastic fluids like plastics, paints, inks, etc. For both design and analysis purposes, it is often a matter of interest to understand the features of the displacing action realized by meshing of the gears and the description of the behavior of the leakages for this kind of pumps. However, very limited work can be found in literature about methodologies suitable to model such phenomena. This article describes the technique of modelling external gear pumps that operate with non-Newtonian fluids. In particular, it explains how the displacing action of the unit can be modelled using a lumped parameter approach which involves dividing fluid domain into several control volumes and internal flow connections. This work is built upon the HYGESim simulation tool, conceived by the authors' research team in the last decade, which is for the first time extended for the simulation of non-Newtonian fluids. The article also describes several comparisons between simulation results and experimental data obtained from numerous experiments performed for validation of the presented methodology. Finally, operation of external gear pump with fluids having different viscosity characteristics is discussed.

  4. Derivation and External Validation of Prediction Models for Advanced Chronic Kidney Disease Following Acute Kidney Injury.

    Science.gov (United States)

    James, Matthew T; Pannu, Neesh; Hemmelgarn, Brenda R; Austin, Peter C; Tan, Zhi; McArthur, Eric; Manns, Braden J; Tonelli, Marcello; Wald, Ron; Quinn, Robert R; Ravani, Pietro; Garg, Amit X

    2017-11-14

    Some patients will develop chronic kidney disease after a hospitalization with acute kidney injury; however, no risk-prediction tools have been developed to identify high-risk patients requiring follow-up. To derive and validate predictive models for progression of acute kidney injury to advanced chronic kidney disease. Data from 2 population-based cohorts of patients with a prehospitalization estimated glomerular filtration rate (eGFR) of more than 45 mL/min/1.73 m2 and who had survived hospitalization with acute kidney injury (defined by a serum creatinine increase during hospitalization > 0.3 mg/dL or > 50% of their prehospitalization baseline), were used to derive and validate multivariable prediction models. The risk models were derived from 9973 patients hospitalized in Alberta, Canada (April 2004-March 2014, with follow-up to March 2015). The risk models were externally validated with data from a cohort of 2761 patients hospitalized in Ontario, Canada (June 2004-March 2012, with follow-up to March 2013). Demographic, laboratory, and comorbidity variables measured prior to discharge. Advanced chronic kidney disease was defined by a sustained reduction in eGFR less than 30 mL/min/1.73 m2 for at least 3 months during the year after discharge. All participants were followed up for up to 1 year. The participants (mean [SD] age, 66 [15] years in the derivation and internal validation cohorts and 69 [11] years in the external validation cohort; 40%-43% women per cohort) had a mean (SD) baseline serum creatinine level of 1.0 (0.2) mg/dL and more than 20% had stage 2 or 3 acute kidney injury. Advanced chronic kidney disease developed in 408 (2.7%) of 9973 patients in the derivation cohort and 62 (2.2%) of 2761 patients in the external validation cohort. In the derivation cohort, 6 variables were independently associated with the outcome: older age, female sex, higher baseline serum creatinine value, albuminuria, greater severity of acute kidney injury, and higher

  5. The use of Geographic Information System (GIS) and non-GIS methods to assess the external validity of samples postcollection.

    Science.gov (United States)

    Richardson, Esther; Good, Margaret; McGrath, Guy; More, Simon J

    2009-09-01

    External validity is fundamental to veterinary diagnostic investigation, reflecting the accuracy with which sample results can be extrapolated to a broader population of interest. Probability sampling methods are routinely used during the collection of samples from populations, specifically to maximize external validity. Nonprobability sampling (e.g., of blood samples collected as part of routine surveillance programs or laboratory submissions) may provide useful data for further posthoc epidemiological analysis, adding value to the collection and submission of samples. As the sample has already been submitted, the analyst or investigator does not have any control over the sampling methodology, and hence external validity as routine probability sampling methods may not have been employed. The current study describes several Geographic Information System (GIS) and non-GIS methods, applied posthoc, to assess the external validity of samples collected using both probability and nonprobability sampling methods. These methods could equally be employed for inspecting other datasets. Mapping was conducted using ArcView 9.1. Based on this posthoc assessment, results from the random field sample could provide an externally valid, albeit relatively imprecise, estimate of national disease prevalence, of disease prevalence in 3 of the 4 provinces (all but Ulster, in the north and northwest, where sample size was small), and in beef and dairy herds. This study provides practical methods for examining the external validity of samples postcollection.

  6. Development and External Validation of a Prognostic Nomogram for Metastatic Uveal Melanoma

    Science.gov (United States)

    Valpione, Sara; Moser, Justin C.; Parrozzani, Raffaele; Bazzi, Marco; Mansfield, Aaron S.; Mocellin, Simone; Pigozzo, Jacopo; Midena, Edoardo; Markovic, Svetomir N.; Aliberti, Camillo; Campana, Luca G.; Chiarion-Sileni, Vanna

    2015-01-01

    Background Approximately 50% of patients with uveal melanoma (UM) will develop metastatic disease, usually involving the liver. The outcome of metastatic UM (mUM) is generally poor and no standard therapy has been established. Additionally, clinicians lack a validated prognostic tool to evaluate these patients. The aim of this work was to develop a reliable prognostic nomogram for clinicians. Patients and Methods Two cohorts of mUM patients, from Veneto Oncology Institute (IOV) (N=152) and Mayo Clinic (MC) (N=102), were analyzed to develop and externally validate, a prognostic nomogram. Results The median survival of mUM was 17.2 months in the IOV cohort and 19.7 in the MC cohort. Percentage of liver involvement (HR 1.6), elevated levels of serum LDH (HR 1.6), and a WHO performance status=1 (HR 1.5) or 2–3 (HR 4.6) were associated with worse prognosis. Longer disease-free interval from diagnosis of UM to that of mUM conferred a survival advantage (HR 0.9). The nomogram had a concordance probability of 0.75 (SE .006) in the development dataset (IOV), and 0.80 (SE .009) in the external validation (MC). Nomogram predictions were well calibrated. Conclusions The nomogram, which includes percentage of liver involvement, LDH levels, WHO performance status and disease free-interval accurately predicts the prognosis of mUM and could be useful for decision-making and risk stratification for clinical trials. PMID:25780931

  7. Development and Validation of a Mobile Device-based External Ventricular Drain Simulator.

    Science.gov (United States)

    Morone, Peter J; Bekelis, Kimon; Root, Brandon K; Singer, Robert J

    2017-10-01

    Multiple external ventricular drain (EVD) simulators have been created, yet their cost, bulky size, and nonreusable components limit their accessibility to residency programs. To create and validate an animated EVD simulator that is accessible on a mobile device. We developed a mobile-based EVD simulator that is compatible with iOS (Apple Inc., Cupertino, California) and Android-based devices (Google, Mountain View, California) and can be downloaded from the Apple App and Google Play Store. Our simulator consists of a learn mode, which teaches users the procedure, and a test mode, which assesses users' procedural knowledge. Twenty-eight participants, who were divided into expert and novice categories, completed the simulator in test mode and answered a postmodule survey. This was graded using a 5-point Likert scale, with 5 representing the highest score. Using the survey results, we assessed the module's face and content validity, whereas construct validity was evaluated by comparing the expert and novice test scores. Participants rated individual survey questions pertaining to face and content validity a median score of 4 out of 5. When comparing test scores, generated by the participants completing the test mode, the experts scored higher than the novices (mean, 71.5; 95% confidence interval, 69.2 to 73.8 vs mean, 48; 95% confidence interval, 44.2 to 51.6; P mobile-based EVD simulator that is inexpensive, reusable, and accessible. Our results demonstrate that this simulator is face, content, and construct valid. Copyright © 2017 by the Congress of Neurological Surgeons

  8. Prognosis in moderate and severe traumatic brain injury: External validation of the IMPACT models and the role of extracranial injuries

    NARCIS (Netherlands)

    Lingsma, Hester; Andriessen, Teuntje M. J. C.; Haitsema, Iain; Horn, Janneke; van der Naalt, Joukje; Franschman, Gaby; Maas, Andrew I. R.; Vos, Pieter E.; Steyerberg, Ewout W.

    2013-01-01

    BACKGROUND: Several prognostic models to predict outcome in traumatic brain injury (TBI) have been developed, but few are externally validated. We aimed to validate the International Mission on Prognosis and Analysis of Clinical Trials in TBI (IMPACT) prognostic models in a recent unselected patient

  9. The relationship between external and internal validity of randomized controlled trials: A sample of hypertension trials from China

    Directory of Open Access Journals (Sweden)

    Xin Zhang

    2015-10-01

    Conclusion: Several components relate to the external validity of RCTs do associate with the internal validity, that do not stand in an easy relationship to each other. Regarding the poor reporting, other possible links between two variables need to trace in the future methodological researches.

  10. External validation of the ability of the DRAGON score to predict outcome after thrombolysis treatment.

    Science.gov (United States)

    Ovesen, C; Christensen, A; Nielsen, J K; Christensen, H

    2013-11-01

    Easy-to-perform and valid assessment scales for the effect of thrombolysis are essential in hyperacute stroke settings. Because of this we performed an external validation of the DRAGON scale proposed by Strbian et al. in a Danish cohort. All patients treated with intravenous recombinant plasminogen activator between 2009 and 2011 were included. Upon admission all patients underwent physical and neurological examination using the National Institutes of Health Stroke Scale along with non-contrast CT scans and CT angiography. Patients were followed up through the Outpatient Clinic and their modified Rankin Scale (mRS) was assessed after 3 months. Three hundred and three patients were included in the analysis. The DRAGON scale proved to have a good discriminative ability for predicting highly unfavourable outcome (mRS 5-6) (area under the curve-receiver operating characteristic [AUC-ROC]: 0.89; 95% confidence interval [CI] 0.81-0.96; pDRAGON scale provided good discriminative capability (AUC-ROC: 0.89; 95% CI 0.78-1.0; p=0.003) for highly unfavourable outcome. We confirmed the validity of the DRAGON scale in predicting outcome after thrombolysis treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. External validation of the NUn score for predicting anastomotic leakage after oesophageal resection.

    Science.gov (United States)

    Paireder, Matthias; Jomrich, Gerd; Asari, Reza; Kristo, Ivan; Gleiss, Andreas; Preusser, Matthias; Schoppmann, Sebastian F

    2017-08-29

    Early detection of anastomotic leakage (AL) after oesophageal resection for malignancy is crucial. This retrospective study validates a risk score, predicting AL, which includes C-reactive protein, albumin and white cell count in patients undergoing oesophageal resection between 2003 and 2014. For validation of the NUn score a receiver operating characteristic (ROC) curve is estimated. Area under the ROC curve (AUC) is reported with 95% confidence interval (CI). Among 258 patients (79.5% male) 32 patients showed signs of anastomotic leakage (12.4%). NUn score in our data has a median of 9.3 (range 6.2-17.6). The odds ratio for AL was 1.31 (CI 1.03-1.67; p = 0.028). AUC for AL was 0.59 (CI 0.47-0.72). Using the original cutoff value of 10, the sensitivity was 45.2% an the specificity was 73.8%. This results in a positive predictive value of 19.4% and a negative predictive value of 90.6%. The proportion of variation in AL occurrence, which is explained by the NUn score, was 2.5% (PEV = 0.025). This study provides evidence for an external validation of a simple risk score for AL after oesophageal resection. In this cohort, the NUn score is not useful due to its poor discrimination.

  12. Derivation and external validation of a case mix model for the standardized reporting of 30-day stroke mortality rates.

    Science.gov (United States)

    Bray, Benjamin D; Campbell, James; Cloud, Geoffrey C; Hoffman, Alex; James, Martin; Tyrrell, Pippa J; Wolfe, Charles D A; Rudd, Anthony G

    2014-11-01

    Case mix adjustment is required to allow valid comparison of outcomes across care providers. However, there is a lack of externally validated models suitable for use in unselected stroke admissions. We therefore aimed to develop and externally validate prediction models to enable comparison of 30-day post-stroke mortality outcomes using routine clinical data. Models were derived (n=9000 patients) and internally validated (n=18 169 patients) using data from the Sentinel Stroke National Audit Program, the national register of acute stroke in England and Wales. External validation (n=1470 patients) was performed in the South London Stroke Register, a population-based longitudinal study. Models were fitted using general estimating equations. Discrimination and calibration were assessed using receiver operating characteristic curve analysis and correlation plots. Two final models were derived. Model A included age (<60, 60-69, 70-79, 80-89, and ≥90 years), National Institutes of Health Stroke Severity Score (NIHSS) on admission, presence of atrial fibrillation on admission, and stroke type (ischemic versus primary intracerebral hemorrhage). Model B was similar but included only the consciousness component of the NIHSS in place of the full NIHSS. Both models showed excellent discrimination and calibration in internal and external validation. The c-statistics in external validation were 0.87 (95% confidence interval, 0.84-0.89) and 0.86 (95% confidence interval, 0.83-0.89) for models A and B, respectively. We have derived and externally validated 2 models to predict mortality in unselected patients with acute stroke using commonly collected clinical variables. In settings where the ability to record the full NIHSS on admission is limited, the level of consciousness component of the NIHSS provides a good approximation of the full NIHSS for mortality prediction. © 2014 American Heart Association, Inc.

  13. External validation of a decision tree early warning score using only laboratory data

    DEFF Research Database (Denmark)

    Holm Atkins, Tara E; Öhman, Malin C; Brabrand, Mikkel

    2018-01-01

    INTRODUCTION: Early warning scores (EWS) have been developed to identify the degree of illness severity among acutely ill patients. One system, The Laboratory Decision Tree Early Warning Score (LDT-EWS) is wholly laboratory data based. Laboratory data was used in the development of a rare...... computerized method, developing a decision tree analysis. This article externally validates LDT-EWS, which is obligatory for an EWS before clinical use. METHOD: We conducted a retrospective review of prospectively collected data based on a time limited sample of all patients admitted through the medical......) and calibration (precision) as Hosmer-Lemeshow Goodness of fit test. RESULTS: A total of 5858 patients were admitted and 4902 included (83.7%). In-hospital mortality in our final dataset (n=4902) was 3.5%. Discriminatory power (95% CI), identifying in-hospital death was 0.809 (0.777-0.842). Calibration was good...

  14. External validation of the Society of Thoracic Surgeons General Thoracic Surgery Database.

    Science.gov (United States)

    Magee, Mitchell J; Wright, Cameron D; McDonald, Donna; Fernandez, Felix G; Kozower, Benjamin D

    2013-11-01

    The Society of Thoracic Surgeons (STS) General Thoracic Surgery Database (GTSD) reports outstanding results for lung and esophageal cancer resection. However, a major weakness of the GTSD has been the lack of validation of this voluntary registry. The purpose of this study was to perform an external, independent audit to assess the accuracy of the data collection process and the quality of the database. An independent firm was contracted to audit 5% of sites randomly selected from the GTDB in 2011. Audits were performed remotely to maximize the number of audits performed and reduce cost. Auditors compared lobectomy cases submitted to the GTSD with the hospital operative logs to evaluate completeness of the data. In addition, 20 lobectomy records from each site were audited in detail. Agreement rates were calculated for 32 individual data elements, 7 data categories pertaining to patient status or care delivery, and an overall agreement rate for each site. Six process variables were also evaluated to assess best practice for data collection and submission. Ten sites were audited from the 222 participants. Comparison of the 559 submitted lobectomy cases with operative logs from each site identified 28 omissions, a 94.6% agreement rate (discrepancies/site range, 2 to 27). Importantly, cases not submitted had no mortality or major morbidity, indicating a lack of purposeful omission. The aggregate agreement rates for all categories were greater than 90%. The overall data accuracy was 94.9%. External audits of the GTSD validate the accuracy and completeness of the data. Careful examination of unreported cases demonstrated no purposeful omission or gaming. Although these preliminary results are quite good, it is imperative that the audit process is refined and continues to expand along with the GTSD to insure reliability of the database. The audit results are currently being incorporated into educational and quality improvement processes to add further value. Copyright

  15. External validation of the MRI-DRAGON score: early prediction of stroke outcome after intravenous thrombolysis.

    Science.gov (United States)

    Turc, Guillaume; Aguettaz, Pierre; Ponchelle-Dequatre, Nelly; Hénon, Hilde; Naggara, Olivier; Leclerc, Xavier; Cordonnier, Charlotte; Leys, Didier; Mas, Jean-Louis; Oppenheim, Catherine

    2014-01-01

    The aim of our study was to validate in an independent cohort the MRI-DRAGON score, an adaptation of the (CT-) DRAGON score to predict 3-month outcome in acute ischemic stroke patients undergoing MRI before intravenous thrombolysis (IV-tPA). We reviewed consecutive (2009-2013) anterior circulation stroke patients treated within 4.5 hours by IV-tPA in the Lille stroke unit (France), where MRI is the first-line pretherapeutic work-up. We assessed the discrimination and calibration of the MRI-DRAGON score to predict poor 3-month outcome, defined as modified Rankin Score >2, using c-statistic and the Hosmer-Lemeshow test, respectively. We included 230 patients (mean ±SD age 70.4±16.0 years, median [IQR] baseline NIHSS 8 [5]-[14]; poor outcome in 78(34%) patients). The c-statistic was 0.81 (95%CI 0.75-0.87), and the Hosmer-Lemeshow test was not significant (p = 0.54). The MRI-DRAGON score showed good prognostic performance in the external validation cohort. It could therefore be used to inform the patient's relatives about long-term prognosis and help to identify poor responders to IV-tPA alone, who may be candidates for additional therapeutic strategies, if they are otherwise eligible for such procedures based on the institutional criteria.

  16. External validation of the MRI-DRAGON score: early prediction of stroke outcome after intravenous thrombolysis.

    Directory of Open Access Journals (Sweden)

    Guillaume Turc

    Full Text Available The aim of our study was to validate in an independent cohort the MRI-DRAGON score, an adaptation of the (CT- DRAGON score to predict 3-month outcome in acute ischemic stroke patients undergoing MRI before intravenous thrombolysis (IV-tPA.We reviewed consecutive (2009-2013 anterior circulation stroke patients treated within 4.5 hours by IV-tPA in the Lille stroke unit (France, where MRI is the first-line pretherapeutic work-up. We assessed the discrimination and calibration of the MRI-DRAGON score to predict poor 3-month outcome, defined as modified Rankin Score >2, using c-statistic and the Hosmer-Lemeshow test, respectively.We included 230 patients (mean ±SD age 70.4±16.0 years, median [IQR] baseline NIHSS 8 [5]-[14]; poor outcome in 78(34% patients. The c-statistic was 0.81 (95%CI 0.75-0.87, and the Hosmer-Lemeshow test was not significant (p = 0.54.The MRI-DRAGON score showed good prognostic performance in the external validation cohort. It could therefore be used to inform the patient's relatives about long-term prognosis and help to identify poor responders to IV-tPA alone, who may be candidates for additional therapeutic strategies, if they are otherwise eligible for such procedures based on the institutional criteria.

  17. Triviality-quantum decoherence of quantum chromodynamics SU(∞) in the presence of an external strong white-noise electromagnetic field

    International Nuclear Information System (INIS)

    Botelho, Luiz C.L.

    2004-01-01

    We analyze the triviality-quantum decoherence of Euclidean quantum chromodynamics in the gauge invariant quark current sector in the presence of a very strong external white-noise electromagnetic (strength) field within the context of QCD in the 't Hooft limit of a large number of colors

  18. The relationship between external and internal validity of randomized controlled trials: A sample of hypertension trials from China.

    Science.gov (United States)

    Zhang, Xin; Wu, Yuxia; Ren, Pengwei; Liu, Xueting; Kang, Deying

    2015-10-30

    To explore the relationship between the external validity and the internal validity of hypertension RCTs conducted in China. Comprehensive literature searches were performed in Medline, Embase, Cochrane Central Register of Controlled Trials (CCTR), CBMdisc (Chinese biomedical literature database), CNKI (China National Knowledge Infrastructure/China Academic Journals Full-text Database) and VIP (Chinese scientific journals database) as well as advanced search strategies were used to locate hypertension RCTs. The risk of bias in RCTs was assessed by a modified scale, Jadad scale respectively, and then studies with 3 or more grading scores were included for the purpose of evaluating of external validity. A data extract form including 4 domains and 25 items was used to explore relationship of the external validity and the internal validity. Statistic analyses were performed by using SPSS software, version 21.0 (SPSS, Chicago, IL). 226 hypertension RCTs were included for final analysis. RCTs conducted in university affiliated hospitals (P internal validity. Multi-center studies (median = 4.0, IQR = 2.0) were scored higher internal validity score than single-center studies (median = 3.0, IQR = 1.0) (P internal validity (P = 0.004). Multivariate regression indicated sample size, industry-funding, quality of life (QOL) taken as measure and the university affiliated hospital as trial setting had statistical significance (P external validity of RCTs do associate with the internal validity, that do not stand in an easy relationship to each other. Regarding the poor reporting, other possible links between two variables need to trace in the future methodological researches.

  19. Serum Gamma-Glutamyl-Transferase Independently Predicts Outcome After Transarterial Chemoembolization of Hepatocellular Carcinoma: External Validation

    Energy Technology Data Exchange (ETDEWEB)

    Guiu, Boris, E-mail: boris.guiu@chu-dijon.fr; Deschamps, Frederic [Institut Gustave Roussy, Department of Interventional Radiology (France); Boulin, Mathieu [University Hospital, INSERM U866 (France); Boige, Valerie; Malka, David; Ducreux, Michel [Institut Gustave Roussy, Department of Digestive Oncology (France); Hillon, Patrick [University Hospital, INSERM U866 (France); Baere, Thierry de [Institut Gustave Roussy, Department of Interventional Radiology (France)

    2012-10-15

    Purpose: An Asian study showed that gamma glutamyl transpeptidase (GGT) can predict survival after transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). This study was designed to validate in a European population this biomarker as an independent predictor of outcome after TACE of HCC and to determine a threshold value for clinical use. Methods: In 88 consecutive patients treated by TACE for HCC, the optimal threshold for GGT serum level was determined by a ROC analysis. Endpoints were time-to-treatment failure (TTTF) and overall survival (OS). All multivariate models were internally validated using bootstrapping (90 replications). Results: Median follow-up lasted 373 days, and median overall survival was 748 days. The optimal threshold for GGT was 165 U/L (sensitivity: 89.3%; specificity: 56.7%; area under the ROC curve: 0.7515). Median TTTF was shorter when GGT was {>=}165 U/L (281 days vs. 850 days; P < 0.001). GGT {>=}165 U/L (hazard ratio (HR) = 2.06; P = 0.02), WHO PS of 2 (HR = 5.4; P = 0.002), and tumor size (HR = 1.12; P = 0.014) were independently associated with shorter TTTF. Median OS was shorter when GGT was {>=}165 U/L (508 days vs. not reached; P < 0.001). GGT {>=} 165 U/L (HR = 3.05; P = 0.029), WHO PS of 2 (HR = 12.95; P < 0.001), alfa-fetoprotein (HR = 2.9; P = 0.01), and tumor size (HR = 1.096; P = 0.013) were independently associated with shorter OS. The results were confirmed by bootstrapping. Conclusions: Our results provide in a European population the external validation of GGT as an independent predictor of outcome after TACE of HCC. A serum level of GGT {>=} 165 U/L is independently associated with both shorter TTTF and OS.

  20. Serum Gamma-Glutamyl-Transferase Independently Predicts Outcome After Transarterial Chemoembolization of Hepatocellular Carcinoma: External Validation

    International Nuclear Information System (INIS)

    Guiu, Boris; Deschamps, Frédéric; Boulin, Mathieu; Boige, Valérie; Malka, David; Ducreux, Michel; Hillon, Patrick; Baère, Thierry de

    2012-01-01

    Purpose: An Asian study showed that gamma glutamyl transpeptidase (GGT) can predict survival after transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). This study was designed to validate in a European population this biomarker as an independent predictor of outcome after TACE of HCC and to determine a threshold value for clinical use. Methods: In 88 consecutive patients treated by TACE for HCC, the optimal threshold for GGT serum level was determined by a ROC analysis. Endpoints were time-to-treatment failure (TTTF) and overall survival (OS). All multivariate models were internally validated using bootstrapping (90 replications). Results: Median follow-up lasted 373 days, and median overall survival was 748 days. The optimal threshold for GGT was 165 U/L (sensitivity: 89.3%; specificity: 56.7%; area under the ROC curve: 0.7515). Median TTTF was shorter when GGT was ≥165 U/L (281 days vs. 850 days; P < 0.001). GGT ≥165 U/L (hazard ratio (HR) = 2.06; P = 0.02), WHO PS of 2 (HR = 5.4; P = 0.002), and tumor size (HR = 1.12; P = 0.014) were independently associated with shorter TTTF. Median OS was shorter when GGT was ≥165 U/L (508 days vs. not reached; P < 0.001). GGT ≥ 165 U/L (HR = 3.05; P = 0.029), WHO PS of 2 (HR = 12.95; P < 0.001), alfa-fetoprotein (HR = 2.9; P = 0.01), and tumor size (HR = 1.096; P = 0.013) were independently associated with shorter OS. The results were confirmed by bootstrapping. Conclusions: Our results provide in a European population the external validation of GGT as an independent predictor of outcome after TACE of HCC. A serum level of GGT ≥ 165 U/L is independently associated with both shorter TTTF and OS.

  1. Prevalence of diabetes treatment effect modifiers: the external validity of trials to older adults.

    Science.gov (United States)

    Weiss, Carlos O; Boyd, Cynthia M; Wolff, Jennifer L; Leff, Bruce

    2012-08-01

    Potential treatment effect modifiers (TEMs) are specific diseases or conditions with a well-described mechanism for treatment effect modification. The prevalence of TEMs in older adults with type 2 diabetes mellitus (DM) is unknown. Objectives were to 1) determine the prevalence of pre-specified potential TEMs; 2) demonstrate the potential impact of TEMs in the older adult population using a simulated trial; 3) identify TEM combinations associated with number of hospitalizations to test construct validity. Data are from the nationally-representative United States National Health and Examination Survey, 1999-2004: 8646 Civilian, non-institutionalized adults aged 45-64 or 65+ years, including 1443 with DM. TEMs were anemia, congestive heart failure, liver inflammation, polypharmacy, renal insufficiency, cognitive impairment, dizziness, frequent mental distress, mobility difficulty, and visual impairment. A trial was simulated to examine prevalence of potential TEM impact. The cross-sectional association between TEM patterns and number of hospitalizations was estimated to assess construct validity. The prevalence of TEMs was substantial such that 19.0% (95% CI 14.8-23.2) of middle-aged adults and 38.0% (95% CI 33.4-42.5) of older adults had any two. A simulated trial with modest levels of interaction suggested the prevalence of TEMs could nullify treatment benefit in 3.9-27.2% of older adults with DM. Compared to having DM alone, hospitalization rate was increased by several combinations of TEMs with substantial prevalence. We provide national benchmarks that can be used to evaluate TEM prevalence reported by clinical trials of DM, and correspondingly their external validity to older adults.

  2. Predicting the success of IVF: external validation of the van Loendersloot's model.

    Science.gov (United States)

    Sarais, Veronica; Reschini, Marco; Busnelli, Andrea; Biancardi, Rossella; Paffoni, Alessio; Somigliana, Edgardo

    2016-06-01

    Is the predictive model for IVF success proposed by van Loendersloot et al. valid in a different geographical and cultural context? The model discriminates well but was less accurate than in the original context where it was developed. Several independent groups have developed models that combine different variables with the aim of estimating the chance of pregnancy with IVF but only four of them have been externally validated. One of these four, the van Loendersloot's model, deserves particular attention and further investigation for at least three reasons; (i) the reported area under the receiver operating characteristics curve (c-statistics) in the temporal validation setting was the highest reported to date (0.68), (ii) the perspective of the model is clinically wise since it includes variables obtained from previous failed cycles, if any, so it can be applied to any women entering an IVF cycle, (iii) the model lacks external validation in a geographically different center. Retrospective cohort study of women undergoing oocyte retrieval for IVF between January 2013 and December 2013 at the infertility unit of the Fondazione Ca' Granda, Ospedale Maggiore Policlinico of Milan, Italy. Only the first oocyte retrieval cycle performed during the study period was included in the study. Women with previous IVF cycles were excluded if the last one before the study cycle was in another center. The main outcome was the cumulative live birth rate per oocytes retrieval. Seven hundred seventy-two women were selected. Variables included in the van Loendersloot's model and the relative weights (beta) were used. The variable resulting from this combination (Y) was transformed into a probability. The discriminatory capacity was assessed using the c-statistics. Calibration was made using a logistic regression that included Y as the unique variable and live birth as the outcome. Data are presented using both the original and the calibrated models. Performance was evaluated

  3. Development and validation of the ExPRESS instrument for primary health care providers' evaluation of external supervision.

    Science.gov (United States)

    Schriver, Michael; Cubaka, Vincent Kalumire; Vedsted, Peter; Besigye, Innocent; Kallestrup, Per

    2018-01-01

    External supervision of primary health care facilities to monitor and improve services is common in low-income countries. Currently there are no tools to measure the quality of support in external supervision in these countries. To develop a provider-reported instrument to assess the support delivered through external supervision in Rwanda and other countries. "External supervision: Provider Evaluation of Supervisor Support" (ExPRESS) was developed in 18 steps, primarily in Rwanda. Content validity was optimised using systematic search for related instruments, interviews, translations, and relevance assessments by international supervision experts as well as local experts in Nigeria, Kenya, Uganda and Rwanda. Construct validity and reliability were examined in two separate field tests, the first using exploratory factor analysis and a test-retest design, the second for confirmatory factor analysis. We included 16 items in section A ('The most recent experience with an external supervisor'), and 13 items in section B ('The overall experience with external supervisors'). Item-content validity index was acceptable. In field test I, test-retest had acceptable kappa values and exploratory factor analysis suggested relevant factors in sections A and B used for model hypotheses. In field test II, models were tested by confirmatory factor analysis fitting a 4-factor model for section A, and a 3-factor model for section B. ExPRESS is a promising tool for evaluation of the quality of support of primary health care providers in external supervision of primary health care facilities in resource-constrained settings. ExPRESS may be used as specific feedback to external supervisors to help identify and address gaps in the supervision they provide. Further studies should determine optimal interpretation of scores and the number of respondents needed per supervisor to obtain precise results, as well as test the functionality of section B.

  4. Can Findings from Randomized Controlled Trials of Social Skills Training in Autism Spectrum Disorder Be Generalized? The Neglected Dimension of External Validity

    Science.gov (United States)

    Jonsson, Ulf; Olsson, Nora Choque; Bölte, Sven

    2016-01-01

    Systematic reviews have traditionally focused on internal validity, while external validity often has been overlooked. In this study, we systematically reviewed determinants of external validity in the accumulated randomized controlled trials of social skills group interventions for children and adolescents with autism spectrum disorder. We…

  5. Clinical endpoint adjudication in a contemporary all-comers coronary stent investigation: methodology and external validation.

    Science.gov (United States)

    Vranckx, Pascal; McFadden, Eugene; Cutlip, Donald E; Mehran, Roxana; Swart, Michael; Kint, P P; Zijlstra, Felix; Silber, Sigmund; Windecker, Stephan; Serruys, Patrick W C J

    2013-01-01

    Globalisation in coronary stent research calls for harmonization of clinical endpoint definitions and event adjudication. Little has been published about the various processes used for event adjudication or their impact on outcome reporting. We performed a validation of the clinical event committee (CEC) adjudication process on 100 suspected events in the RESOLUTE All-comers trial (Resolute-AC). Two experienced Clinical Research Organisations (CRO) that had already extensive internal validation processes in place, participated in the study. After initial adjudication by the primary-CEC, events were cross-adjudicated by an external-CEC using the same definitions. Major discrepancies affecting the primary end point of target-lesion failure (TLF), a composite of cardiac death, target vessel myocardial infarction (TV-MI), or clinically-indicated target-lesion revascularization (CI-TLR), were analysed by an independent oversight committee who provided recommendations for harmonization. Discordant adjudications were reconsidered by the primary CEC. Subsequently, the RAC database was interrogated for cases that based on these recommendations merited re-adjudication and these cases were also re-adjudicated by the primary CEC. Final discrepancies in adjudication of individual components of TLF occurred in 7 out of 100 events in 5 patients. Discrepancies for the (hierarchical) primary endpoint occurred in 5 events (2 cardiac deaths and 3 TV-MI). After application of harmonization recommendations to the overall RAC population (n=2292), the primary CEC adjudicated 3 additional clinical-TLRs and considered 1 TV-MI as no event. A harmonization process provided a high level of concordance for event adjudication and improved accuracy for final event reporting. These findings suggest it is feasible to pool clinical event outcome data across clinical trials even when different CECs are responsible for event adjudication. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Multicentre external validation of the BIMC model for solid solitary pulmonary nodule malignancy prediction

    Energy Technology Data Exchange (ETDEWEB)

    Soardi, Gian Alberto; Perandini, Simone; Motton, Massimiliano; Montemezzi, Stefania [AOUI Verona, UOC Radiologia, Ospedale Maggiore di Borgo Trento, Verona (Italy); Larici, Anna Rita; Del Ciello, Annemilia [Universita Cattolica del Sacro Cuore, Dipartimento di Scienze Radiologiche, Roma (Italy); Rizzardi, Giovanna [UO Chirurgia Toracica, Ospedale Humanitas Gavazzeni, Bergamo (Italy); Solazzo, Antonio [UO Radiologia, Ospedale Humanitas Gavazzeni, Bergamo (Italy); Mancino, Laura [UO Pneumologia, Ospedale dell' Angelo di Mestre, Mestre (Italy); Bernhart, Marco [UO Radiologia, Ospedale dell' Angelo di Mestre, Mestre (Italy)

    2017-05-15

    To provide multicentre external validation of the Bayesian Inference Malignancy Calculator (BIMC) model by assessing diagnostic accuracy in a cohort of solitary pulmonary nodules (SPNs) collected in a clinic-based setting. To assess model impact on SPN decision analysis and to compare findings with those obtained via the Mayo Clinic model. Clinical and imaging data were retrospectively collected from 200 patients from three centres. Accuracy was assessed by means of receiver-operating characteristic (ROC) areas under the curve (AUCs). Decision analysis was performed by adopting both the American College of Chest Physicians (ACCP) and the British Thoracic Society (BTS) risk thresholds. ROC analysis showed an AUC of 0.880 (95 % CI, 0.832-0.928) for the BIMC model and of 0.604 (95 % CI, 0.524-0.683) for the Mayo Clinic model. Difference was 0.276 (95 % CI, 0.190-0.363, P < 0.0001). Decision analysis showed a slightly reduced number of false-negative and false-positive results when using ACCP risk thresholds. The BIMC model proved to be an accurate tool when characterising SPNs. In a clinical setting it can distinguish malignancies from benign nodules with minimal errors by adopting current ACCP or BTS risk thresholds and guiding lesion-tailored diagnostic and interventional procedures during the work-up. (orig.)

  7. An External Independent Validation of APACHE IV in a Malaysian Intensive Care Unit.

    Science.gov (United States)

    Wong, Rowena S Y; Ismail, Noor Azina; Tan, Cheng Cheng

    2015-04-01

    Intensive care unit (ICU) prognostic models are predominantly used in more developed nations such as the United States, Europe and Australia. These are not that popular in Southeast Asian countries due to costs and technology considerations. The purpose of this study is to evaluate the suitability of the acute physiology and chronic health evaluation (APACHE) IV model in a single centre Malaysian ICU. A prospective study was conducted at the single centre ICU in Hospital Sultanah Aminah (HSA) Malaysia. External validation of APACHE IV involved a cohort of 916 patients who were admitted in 2009. Model performance was assessed through its calibration and discrimination abilities. A first-level customisation using logistic regression approach was also applied to improve model calibration. APACHE IV exhibited good discrimination, with an area under receiver operating characteristic (ROC) curve of 0.78. However, the model's overall fit was observed to be poor, as indicated by the Hosmer-Lemeshow goodness-of-fit test (Ĉ = 113, P discrimination was not affected. APACHE IV is not suitable for application in HSA ICU, without further customisation. The model's lack of fit in the Malaysian study is attributed to differences in the baseline characteristics between HSA ICU and APACHE IV datasets. Other possible factors could be due to differences in clinical practice, quality and services of health care systems between Malaysia and the United States.

  8. Effort-Based Decision-Making Paradigms for Clinical Trials in Schizophrenia: Part 2—External Validity and Correlates.

    Science.gov (United States)

    Horan, William P; Reddy, L Felice; Barch, Deanna M; Buchanan, Robert W; Dunayevich, Eduardo; Gold, James M; Marder, Steven R; Wynn, Jonathan K; Young, Jared W; Green, Michael F

    2015-09-01

    Effort-based decision making has strong conceptual links to the motivational disturbances that define a key subdomain of negative symptoms. However, the extent to which effort-based decision-making performance relates to negative symptoms, and other clinical and functionally important variables has yet to be systematically investigated. In 94 clinically stable outpatients with schizophrenia, we examined the external validity of 5 effort-based paradigms, including the Effort Expenditure for Rewards, Balloon Effort, Grip Strength Effort, Deck Choice Effort, and Perceptual Effort tasks. These tasks covered 3 types of effort: physical, cognitive, and perceptual. Correlations between effort related performance and 6 classes of variables were examined, including: (1) negative symptoms, (2) clinically rated motivation and community role functioning, (3) self-reported motivational traits, (4) neurocognition, (5) other psychiatric symptoms and clinical/demographic characteristics, and (6) subjective valuation of monetary rewards. Effort paradigms showed small to medium relationships to clinical ratings of negative symptoms, motivation, and functioning, with the pattern more consistent for some measures than others. They also showed small to medium relations with neurocognitive functioning, but were generally unrelated to other psychiatric symptoms, self-reported traits, antipsychotic medications, side effects, and subjective valuation of money. There were relatively strong interrelationships among the effort measures. In conjunction with findings from a companion psychometric article, all the paradigms warrant further consideration and development, and 2 show the strongest potential for clinical trial use at this juncture. © The Author 2015. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  9. External validity of sentiment mining reports: Can current methods identify demographic biases, event biases, and manipulation of reviews?

    NARCIS (Netherlands)

    Wijnhoven, Alphonsus B.J.M.; Bloemen, Oscar

    2014-01-01

    Many publications in sentiment mining provide new techniques for improved accuracy in extracting features and corresponding sentiments in texts. For the external validity of these sentiment reports, i.e., the applicability of the results to target audiences, it is important to well analyze data of

  10. A Psychometric Validation of the Internal and External Motivation to Respond without Prejudice toward People with Disabilities Scale

    Science.gov (United States)

    Pruett, Steven R.; Deiches, Jon; Pfaller, Joseph; Moser, Erin; Chan, Fong

    2014-01-01

    Objective: To determine the factorial validity of the Internal and External Motivation to Respond without Prejudice toward People with Disabilities Scale (D-IMS/EMS). Design: A quantitative descriptive design using factor analysis. Participants: 233 rehabilitation counseling and rehabilitation services students. Results: Both exploratory and…

  11. External validation of a normal tissue complication probability model for radiation-induced hypothyroidism in an independent cohort

    DEFF Research Database (Denmark)

    Rønjom, Marianne F; Brink, Carsten; Bentzen, Søren M

    2015-01-01

    blood tests in the validation cohort relative to the original cohort. However, Pearson's correlation coefficients between model and clinical outcome were high: r = 0.97 estimated by the original model versus the original cohort, and r = 0.97 estimated by the original model versus the new cohort....... CONCLUSION: Dmean and Vthyroid were significant predictors of RIHT in both cohorts. The original NTCP model demonstrated external validity owing to high Pearson's correlation coefficients between estimated and observed incidence rates of RIHT in the original as well as in the validation cohort. This model...

  12. Methods for evaluating physical processes in strong external fields at e{sup +}e{sup -} colliders. Furry picture and quasi-classical approach

    Energy Technology Data Exchange (ETDEWEB)

    Porto, Stefano [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Hartin, Anthony [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Moortgat-Pick, Gudrid [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-04-15

    Future linear colliders designs, ILC and CLIC, are expected to be powerful machines for the discovery of Physics Beyond the Standard Model and subsequent precision studies. However, due to the intense beams (high luminosity, high energy), strong electromagnetic fields occur in the beam-beam interaction region. In the context of precision high energy physics, the presence of such strong fields may yield sensitive corrections to the observed electron-positron processes. The Furry picture of quantum states gives a conceptually simple tool to treat physics processes in an external field. A generalization of the quasi-classical operator method (QOM) as an approximation is considered too.

  13. Differentiating weak ties and strong ties among external sources of influences for enterprise resource planning (ERP) adoption

    Science.gov (United States)

    Aubert, Benoit; Léger, Pierre-Majorique; Larocque, Denis

    2012-05-01

    Enterprise resource planning (ERP) systems represent a major IT adoption decision. ERP adoption decisions, in the chemicals and allied products sectors, were examined between 1994 and 2005. Networks of strong ties and weak ties partners are investigated. Results show that neighbouring companies linked with strong ties can have an influence on organisations making such adoption decision. Past decisions made by major trading partners have a significant influence on the decision to adopt an ERP system for a given organisation. This reflects the complex nature of the knowledge required for such adoption.

  14. External validation of scoring systems in risk stratification of upper gastrointestinal bleeding.

    Science.gov (United States)

    Anchu, Anna Cherian; Mohsina, Subair; Sureshkumar, Sathasivam; Mahalakshmy, T; Kate, Vikram

    2017-03-01

    The aim of this study was to externally validate the four commonly used scoring systems in the risk stratification of patients with upper gastrointestinal bleed (UGIB). Patients of UGIB who underwent endoscopy within 24 h of presentation were stratified prospectively using the pre-endoscopy Rockall score (PRS) >0, complete Rockall score (CRS) >2, Glasgow Blatchford bleeding scores (GBS) >3, and modified GBS (m-GBS) >3 scores. Patients were followed up to 30 days. Prognostic accuracy of the scores was done by comparing areas under curve (AUC) in terms of overall risk stratification, re-bleeding, mortality, need for intervention, and length of hospitalization. One hundred and seventy-five patients were studied. All four scores performed better in the overall risk stratification on AUC [PRS = 0.566 (CI: 0.481-0.651; p-0.043)/CRS = 0.712 (CI: 0.634-0.790); p0.001); m-GBS = 0.802 (CI: 0.734-0.871; pbleed [AUC-0.679 (CI: 0.579-0.780; p = 0.003)]. All the scoring systems except PRS were found to be significantly better in detecting 30-day mortality with a high AUC (CRS = 0.798; p-0.042)/GBS = 0.833; p-0.023); m-GBS = 0.816; p-0.031). All four scores demonstrated significant accuracy in the risk stratification of non-variceal patients; however, only GBS and m-GBS were significant in variceal etiology. Higher cutoff scores achieved better sensitivity/specificity [RS > 0 (50/60.8), CRS > 1 (87.5/50.6), GBS > 7 (88.5/63.3), m-GBS > 7(82.3/72.6)] in the risk stratification. GBS and m-GBS appear to be more valid in risk stratification of UGIB patients in this region. Higher cutoff values achieved better predictive accuracy.

  15. Characteristics of a multisensor system for non invasive glucose monitoring with external validation and prospective evaluation.

    Science.gov (United States)

    Caduff, Andreas; Mueller, Martin; Megej, Alexander; Dewarrat, Francois; Suri, Roland E; Klisic, Jelena; Donath, Marc; Zakharov, Pavel; Schaub, Dominik; Stahel, Werner A; Talary, Mark S

    2011-05-15

    The Multisensor Glucose Monitoring System (MGMS) features non invasive sensors for dielectric characterisation of the skin and underlying tissue in a wide frequency range (1 kHz-100 MHz, 1 and 2 GHz) as well as optical characterisation. In this paper we describe the results of using an MGMS in a miniaturised housing with fully integrated sensors and battery. Six patients with Type I Diabetes Mellitus (age 44±16 y; BMI 24.1±1.3 kg/m(2), duration of diabetes 27±12 y; HbA1c 7.3±1.0%) wore a single Multisensor at the upper arm position and performed a total of 45 in-clinic study days with 7 study days per patient on average (min. 5 and max. 10). Glucose changes were induced either orally or by i.v. glucose administration and the blood glucose was measured routinely. Several prospective data evaluation routines were applied to evaluate the data. The results are shown using one of the restrictive data evaluation routines, where measurements from the first 22 study days were used to train a linear regression model. The global model was then prospectively applied to the data of the remaining 23 study days to allow for an external validation of glucose prediction. The model application yielded a Mean Absolute Relative Difference of 40.8%, a Mean Absolute Difference of 51.9 mg dL(-1), and a correlation of 0.84 on average per study day. The Clarke error grid analyses showed 89.0% in A+B, 4.5% in C, 4.6% in D and 1.9% in the E region. Prospective application of a global, purely statistical model, demonstrates that glucose variations can be tracked non invasively by the MGMS in most cases under these conditions. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. European Randomized Study of Screening for Prostate Cancer Risk Calculator: External Validation, Variability, and Clinical Significance.

    Science.gov (United States)

    Gómez-Gómez, Enrique; Carrasco-Valiente, Julia; Blanca-Pedregosa, Ana; Barco-Sánchez, Beatriz; Fernandez-Rueda, Jose Luis; Molina-Abril, Helena; Valero-Rosa, Jose; Font-Ugalde, Pilar; Requena-Tapia, Maria José

    2017-04-01

    To externally validate the European Randomized Study of Screening for Prostate Cancer (ERSPC) risk calculator (RC) and to evaluate its variability between 2 consecutive prostate-specific antigen (PSA) values. We prospectively catalogued 1021 consecutive patients before prostate biopsy for suspicion of prostate cancer (PCa). The risk of PCa and significant PCa (Gleason score ≥7) from 749 patients was calculated according to ERSPC-RC (digital rectal examination-based version 3 of 4) for 2 consecutive PSA tests per patient. The calculators' predictions were analyzed using calibration plots and the area under the receiver operating characteristic curve (area under the curve). Cohen kappa coefficient was used to compare the ability and variability. Of 749 patients, PCa was detected in 251 (33.5%) and significant PCa was detected in 133 (17.8%). Calibration plots showed an acceptable parallelism and similar discrimination ability for both PSA levels with an area under the curve of 0.69 for PCa and 0.74 for significant PCa. The ERSPC showed 226 (30.2%) unnecessary biopsies with the loss of 10 significant PCa. The variability of the RC was 16% for PCa and 20% for significant PCa, and a higher variability was associated with a reduced risk of significant PCa. We can conclude that the performance of the ERSPC-RC in the present cohort shows a high similitude between the 2 PSA levels; however, the RC variability value is associated with a decreased risk of significant PCa. The use of the ERSPC in our cohort detects a high number of unnecessary biopsies. Thus, the incorporation of ERSPC-RC could help the clinical decision to carry out a prostate biopsy. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. External validity of randomized controlled trials of glycaemic control and vascular disease: how representative are participants?

    Science.gov (United States)

    Saunders, C; Byrne, C D; Guthrie, B; Lindsay, R S; McKnight, J A; Philip, S; Sattar, N; Walker, J J; Wild, S H

    2013-03-01

    To describe the proportion of people with Type 2 diabetes living in Scotland who meet eligibility criteria for inclusion in several large randomized controlled trials of glycaemic control to inform physicians and guideline developers about the generalizibility of trial results. A literature review was performed to identify large trials assessing the impact of glycaemic control on risk of macrovascular disease. Inclusion and exclusion criteria from each trial were applied to data on the population of people with a diagnosis of Type 2 diabetes living in Scotland in 2008 (n = 180,590) in a population-based cross-sectional study and the number and proportion of people eligible for each trial was determined. Seven trials were identified. The proportion of people with Type 2 diabetes who met the eligibility criteria for the trials ranged from 3.5 to 50.7%. Trial participants were younger at age of diagnosis of diabetes and at time of trial recruitment than in the Scottish study population. The application of upper age criteria excluded the largest proportion of patients, with up to 39% of people with Type 2 diabetes ineligible for a trial with the most stringent criteria based on age alone. We found that many of the large trials of glycaemic control among people with Type 2 diabetes have limited external validity when applied to a population-based cohort of people with Type 2 diabetes. In particular, the age distribution of trial participants often does not reflect that of people with Type 2 diabetes in a contemporary British population. © 2012 The Authors. Diabetic Medicine © 2012 Diabetes UK.

  18. External validity of randomized controlled trials in older adults, a systematic review.

    Directory of Open Access Journals (Sweden)

    Floor J van Deudekom

    Full Text Available To critically assess the external validity of randomized controlled trials (RCTs it is important to know what older adults have been enrolled in the trials. The aim of this systematic review is to study what proportion of trials specifically designed for older patients report on somatic status, physical and mental functioning, social environment and frailty in the patient characteristics.PubMed was searched for articles published in 2012 and only RCTs were included. Articles were further excluded if not conducted with humans or only secondary analyses were reported. A random sample of 10% was drawn. The current review analyzed this random sample and further selected trials when the reported mean age was ≥ 60 years. We extracted geriatric assessments from the population descriptives or the in- and exclusion criteria.In total 1396 trials were analyzed and 300 trials included. The median of the reported mean age was 66 (IQR 63-70 and the median percentage of men in the trials was 60 (IQR 45-72. In 34% of the RCTs specifically designed for older patients somatic status, physical and mental functioning, social environment or frailty were reported in the population descriptives or the in- and exclusion criteria. Physical and mental functioning was reported most frequently (22% and 14%. When selecting RCTs on a mean age of 70 or 80 years the report of geriatric assessments in the patient characteristics was 46% and 85% respectively but represent only 5% and 1% of the trials.Somatic status, physical and mental functioning, social environment and frailty are underreported even in RCTs specifically designed for older patients published in 2012. Therefore, it is unclear for clinicians to which older patients the results can be applied. We recommend systematic to transparently report these relevant characteristics of older participants included in RCTs.

  19. External validation of prognostic models to predict risk of gestational diabetes mellitus in one Dutch cohort: prospective multicentre cohort study.

    NARCIS (Netherlands)

    Lamain-de Ruiter, M.; Kwee, A.; Naaktgeboren, C.A.; Groot, I. de; Evers, I.M.; Groenendaal, F.; Hering, Y.R.; Huisjes, A.J.M.; Kirpestein, C.; Monincx, W.M.; Siljee, J.E.; Zelfde, A. van't; Oirschot, C.M. van; Vankan-Buitelaar, S.A.; Vonk, M.A.A.W.; Wiegers, T.A.; Zwart, J.J.; Franx, A.; Moons, K.G.M.; Koster, M.P.H.

    2016-01-01

    Objective: To perform an external validation and direct comparison of published prognostic models for early prediction of the risk of gestational diabetes mellitus, including predictors applicable in the first trimester of pregnancy. Design: External validation of all published prognostic models in

  20. Assessing the external validity of model-based estimates of the incidence of heart attack in England: a modelling study

    Directory of Open Access Journals (Sweden)

    Peter Scarborough

    2016-11-01

    Full Text Available Abstract Background The DisMod II model is designed to estimate epidemiological parameters on diseases where measured data are incomplete and has been used to provide estimates of disease incidence for the Global Burden of Disease study. We assessed the external validity of the DisMod II model by comparing modelled estimates of the incidence of first acute myocardial infarction (AMI in England in 2010 with estimates derived from a linked dataset of hospital records and death certificates. Methods Inputs for DisMod II were prevalence rates of ever having had an AMI taken from a population health survey, total mortality rates and AMI mortality rates taken from death certificates. By definition, remission rates were zero. We estimated first AMI incidence in an external dataset from England in 2010 using a linked dataset including all hospital admissions and death certificates since 1998. 95 % confidence intervals were derived around estimates from the external dataset and DisMod II estimates based on sampling variance and reported uncertainty in prevalence estimates respectively. Results Estimates of the incidence rate for the whole population were higher in the DisMod II results than the external dataset (+54 % for men and +26 % for women. Age-specific results showed that the DisMod II results over-estimated incidence for all but the oldest age groups. Confidence intervals for the DisMod II and external dataset estimates did not overlap for most age groups. Conclusion By comparison with AMI incidence rates in England, DisMod II did not achieve external validity for age-specific incidence rates, but did provide global estimates of incidence that are of similar magnitude to measured estimates. The model should be used with caution when estimating age-specific incidence rates.

  1. Production of large volume, strongly magnetized laser-produced plasmas by use of pulsed external magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Albertazzi, B. [LULI, Ecole Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau (France); INRS-EMT, Varennes, Quebec J3X 1S2 (Canada); Beard, J.; Billette, J.; Portugall, O. [LNCMI, UPR 3228, CNRS-UFJ-UPS-INSA, 31400 Toulouse (France); Ciardi, A. [LERMA, Observatoire de Paris, Ecole Normale Superieure, Universite Pierre et Marie Curie, CNRS UMR 8112, Paris (France); Vinci, T.; Albrecht, J.; Chen, S. N.; Da Silva, D.; Hirardin, B.; Nakatsutsumi, M.; Romagnagni, L.; Simond, S.; Veuillot, E.; Fuchs, J. [LULI, Ecole Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau (France); Burris-Mog, T.; Dittrich, S.; Herrmannsdoerfer, T.; Kroll, F.; Nitsche, S. [Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany); and others

    2013-04-15

    The production of strongly magnetized laser plasmas, of interest for laboratory astrophysics and inertial confinement fusion studies, is presented. This is achieved by coupling a 16 kV pulse-power system. This is achieved by coupling a 16 kV pulse-power system, which generates a magnetic field by means of a split coil, with the ELFIE laser facility at Ecole Polytechnique. In order to influence the plasma dynamics in a significant manner, the system can generate, repetitively and without debris, high amplitude magnetic fields (40 T) in a manner compatible with a high-energy laser environment. A description of the system and preliminary results demonstrating the possibility to magnetically collimate plasma jets are given.

  2. Multiple Score Comparison: a network meta-analysis approach to comparison and external validation of prognostic scores

    Directory of Open Access Journals (Sweden)

    Sarah R. Haile

    2017-12-01

    Full Text Available Abstract Background Prediction models and prognostic scores have been increasingly popular in both clinical practice and clinical research settings, for example to aid in risk-based decision making or control for confounding. In many medical fields, a large number of prognostic scores are available, but practitioners may find it difficult to choose between them due to lack of external validation as well as lack of comparisons between them. Methods Borrowing methodology from network meta-analysis, we describe an approach to Multiple Score Comparison meta-analysis (MSC which permits concurrent external validation and comparisons of prognostic scores using individual patient data (IPD arising from a large-scale international collaboration. We describe the challenges in adapting network meta-analysis to the MSC setting, for instance the need to explicitly include correlations between the scores on a cohort level, and how to deal with many multi-score studies. We propose first using IPD to make cohort-level aggregate discrimination or calibration scores, comparing all to a common comparator. Then, standard network meta-analysis techniques can be applied, taking care to consider correlation structures in cohorts with multiple scores. Transitivity, consistency and heterogeneity are also examined. Results We provide a clinical application, comparing prognostic scores for 3-year mortality in patients with chronic obstructive pulmonary disease using data from a large-scale collaborative initiative. We focus on the discriminative properties of the prognostic scores. Our results show clear differences in performance, with ADO and eBODE showing higher discrimination with respect to mortality than other considered scores. The assumptions of transitivity and local and global consistency were not violated. Heterogeneity was small. Conclusions We applied a network meta-analytic methodology to externally validate and concurrently compare the prognostic properties

  3. External validation of the ITA.LI.CA prognostic system for patients with hepatocellular carcinoma: A multicenter cohort study.

    Science.gov (United States)

    Borzio, Mauro; Dionigi, Elena; Rossini, Angelo; Marignani, Massimo; Sacco, Rodolfo; De Sio, Ilario; Bertolini, Emanuela; Francica, Giampiero; Giacomin, Anna; Parisi, Giancarlo; Vicari, Susanna; Toldi, Anna; Salmi, Andrea; Boccia, Sergio; Mitra, Mario; Fornari, Fabio

    2017-11-22

    Several staging systems for hepatocellular carcinoma (HCC) have been developed. The Barcelona Clinic Liver Cancer staging system is considered the best in predicting survival, although limitations have emerged. Recently, the Italian Liver Cancer (ITA.LI.CA) prognostic system, integrating ITA.LI.CA tumor staging (stages 0, A, B1-3, C) with the Child-Turcotte-Pugh score, Eastern Cooperative Oncology Group performance status, and alpha-fetoprotein with a strong ability to predict survival, was proposed. The aim of our study was to provide an external validation of the ITA.LI.CA system in an independent real-life occidental cohort of HCCs. From September 2008 to April 2016, 1,508 patients with cirrhosis and incident HCC were consecutively enrolled in 27 Italian institutions. Clinical, tumor, and treatment-related variables were collected, and patients were stratified according to scores of the Barcelona Clinic Liver Cancer system, ITA.LI.CA prognostic system, Hong Kong Liver Cancer system, Cancer of the Liver Italian Program, Japanese Integrated System, and model to estimate survival in ambulatory patients with hepatocellular carcinoma. Harrell's C-index, Akaike information criterion, and likelihood-ratio test were used to compare the predictive ability of the different systems. A subgroup analysis for treatment category (curative versus palliative) was performed. Median follow-up was 44 months (interquartile range, 23-63 months), and median overall survival was 34 months (interquartile range, 13-82 months). Median age was 71 years, and patients were mainly male individuals and hepatitis C virus carriers. According to ITA.LI.CA tumor staging, 246 patients were in stage 0, 472 were in stage A, 657 were in stages B1/3, and 133 were in stage C. The ITA.LI.CA prognostic system showed the best discriminatory ability (C-index = 0.77) and monotonicity of gradients compared to other systems, and its superiority was also confirmed after stratification for treatment strategy

  4. External Validation Study of First Trimester Obstetric Prediction Models (Expect Study I): Research Protocol and Population Characteristics.

    Science.gov (United States)

    Meertens, Linda Jacqueline Elisabeth; Scheepers, Hubertina Cj; De Vries, Raymond G; Dirksen, Carmen D; Korstjens, Irene; Mulder, Antonius Lm; Nieuwenhuijze, Marianne J; Nijhuis, Jan G; Spaanderman, Marc Ea; Smits, Luc Jm

    2017-10-26

    A number of first-trimester prediction models addressing important obstetric outcomes have been published. However, most models have not been externally validated. External validation is essential before implementing a prediction model in clinical practice. The objective of this paper is to describe the design of a study to externally validate existing first trimester obstetric prediction models, based upon maternal characteristics and standard measurements (eg, blood pressure), for the risk of pre-eclampsia (PE), gestational diabetes mellitus (GDM), spontaneous preterm birth (PTB), small-for-gestational-age (SGA) infants, and large-for-gestational-age (LGA) infants among Dutch pregnant women (Expect Study I). The results of a pilot study on the feasibility and acceptability of the recruitment process and the comprehensibility of the Pregnancy Questionnaire 1 are also reported. A multicenter prospective cohort study was performed in The Netherlands between July 1, 2013 and December 31, 2015. First trimester obstetric prediction models were systematically selected from the literature. Predictor variables were measured by the Web-based Pregnancy Questionnaire 1 and pregnancy outcomes were established using the Postpartum Questionnaire 1 and medical records. Information about maternal health-related quality of life, costs, and satisfaction with Dutch obstetric care was collected from a subsample of women. A pilot study was carried out before the official start of inclusion. External validity of the models will be evaluated by assessing discrimination and calibration. Based on the pilot study, minor improvements were made to the recruitment process and online Pregnancy Questionnaire 1. The validation cohort consists of 2614 women. Data analysis of the external validation study is in progress. This study will offer insight into the generalizability of existing, non-invasive first trimester prediction models for various obstetric outcomes in a Dutch obstetric population

  5. Development and external validation of a risk-prediction model to predict 5-year overall survival in advanced larynx cancer.

    Science.gov (United States)

    Petersen, Japke F; Stuiver, Martijn M; Timmermans, Adriana J; Chen, Amy; Zhang, Hongzhen; O'Neill, James P; Deady, Sandra; Vander Poorten, Vincent; Meulemans, Jeroen; Wennerberg, Johan; Skroder, Carl; Day, Andrew T; Koch, Wayne; van den Brekel, Michiel W M

    2018-05-01

    TNM-classification inadequately estimates patient-specific overall survival (OS). We aimed to improve this by developing a risk-prediction model for patients with advanced larynx cancer. Cohort study. We developed a risk prediction model to estimate the 5-year OS rate based on a cohort of 3,442 patients with T3T4N0N+M0 larynx cancer. The model was internally validated using bootstrapping samples and externally validated on patient data from five external centers (n = 770). The main outcome was performance of the model as tested by discrimination, calibration, and the ability to distinguish risk groups based on tertiles from the derivation dataset. The model performance was compared to a model based on T and N classification only. We included age, gender, T and N classification, and subsite as prognostic variables in the standard model. After external validation, the standard model had a significantly better fit than a model based on T and N classification alone (C statistic, 0.59 vs. 0.55, P statistic to 0.68. A risk prediction model for patients with advanced larynx cancer, consisting of readily available clinical variables, gives more accurate estimations of the estimated 5-year survival rate when compared to a model based on T and N classification alone. 2c. Laryngoscope, 128:1140-1145, 2018. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

  6. Respiration of the external mycelium in the arbuscular mycorrhizal symbiosis shows strong dependence on recent photosynthates and acclimation to temperature.

    Science.gov (United States)

    Heinemeyer, A; Ineson, P; Ostle, N; Fitter, A H

    2006-01-01

    * Although arbuscular mycorrhizal (AM) fungi are a major pathway in the global carbon cycle, their basic biology and, in particular, their respiratory response to temperature remain obscure. * A pulse label of the stable isotope (13)C was applied to Plantago lanceolata, either uninoculated or inoculated with the AM fungus Glomus mosseae. The extra-radical mycelium (ERM) of the fungus was allowed to grow into a separate hyphal compartment excluding roots. We determined the carbon costs of the ERM and tested for a direct temperature effect on its respiration by measuring total carbon and the (13)C:(12)C ratio of respired CO(2). With a second pulse we tested for acclimation of ERM respiration after 2 wk of soil warming. * Root colonization remained unchanged between the two pulses but warming the hyphal compartment increased ERM length. delta(13)C signals peaked within the first 10 h and were higher in mycorrhizal treatments. The concentration of CO(2) in the gas samples fluctuated diurnally and was highest in the mycorrhizal treatments but was unaffected by temperature. Heating increased ERM respiration only after the first pulse and reduced specific ERM respiration rates after the second pulse; however, both pulses strongly depended on radiation flux. * The results indicate a fast ERM acclimation to temperature, and that light is the key factor controlling carbon allocation to the fungus.

  7. Predicting the 6-month risk of severe hypoglycemia among adults with diabetes: Development and external validation of a prediction model.

    Science.gov (United States)

    Schroeder, Emily B; Xu, Stan; Goodrich, Glenn K; Nichols, Gregory A; O'Connor, Patrick J; Steiner, John F

    2017-07-01

    To develop and externally validate a prediction model for the 6-month risk of a severe hypoglycemic event among individuals with pharmacologically treated diabetes. The development cohort consisted of 31,674 Kaiser Permanente Colorado members with pharmacologically treated diabetes (2007-2015). The validation cohorts consisted of 38,764 Kaiser Permanente Northwest members and 12,035 HealthPartners members. Variables were chosen that would be available in electronic health records. We developed 16-variable and 6-variable models, using a Cox counting model process that allows for the inclusion of multiple 6-month observation periods per person. Across the three cohorts, there were 850,992 6-month observation periods, and 10,448 periods with at least one severe hypoglycemic event. The six-variable model contained age, diabetes type, HgbA1c, eGFR, history of a hypoglycemic event in the prior year, and insulin use. Both prediction models performed well, with good calibration and c-statistics of 0.84 and 0.81 for the 16-variable and 6-variable models, respectively. In the external validation cohorts, the c-statistics were 0.80-0.84. We developed and validated two prediction models for predicting the 6-month risk of hypoglycemia. The 16-variable model had slightly better performance than the 6-variable model, but in some practice settings, use of the simpler model may be preferred. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Psychological capital: Internal and external validity of the Psychological Capital Questionnaire (PCQ-24 on a South African sample

    Directory of Open Access Journals (Sweden)

    Gina Görgens-Ekermans

    2013-10-01

    Research purpose: The objectives of this study were to investigate the internal validity (construct and discriminant validity, reliability and external validity (relationship with theoretically relevant variables, namely stress, burnout and work engagement of the PCQ-24. Motivation for the study: Multiple studies have underscored the value of PsyCap within the workplace. In order to harness the full potential of the construct in the South African environment, sound measurement thereof, evidenced by a psychometrically sound instrument, is needed. Research design, approach and method: A cross-sectional survey design was used. The sample consisted of employees at managerial and non-managerial levels, from a medium-sized construction company in the Western Cape, South Africa. In addition to PsyCap, perceived stress, work-related burnout and work engagement were measured. Main findings: The results provided preliminary evidence of construct and discriminant validity, reliability and significant relations with external theoretically relevant variables. Practical/managerial implications: Researchers may confidently use the PCQ-24 to measure the construct of PsyCap and investigate relations with workplace outcomes in the South African environment, informing human relations practices. Contribution/value-add: Preliminary evidence of the psychometric properties of the PCQ-24, which measures the construct of PsyCap (consisting of hope, self-efficacy, resilience and optimism on a South African sample, was provided in this study.

  9. The SCEC Broadband Platform: Open-Source Software for Strong Ground Motion Simulation and Validation

    Science.gov (United States)

    Silva, F.; Goulet, C. A.; Maechling, P. J.; Callaghan, S.; Jordan, T. H.

    2016-12-01

    The Southern California Earthquake Center (SCEC) Broadband Platform (BBP) is a carefully integrated collection of open-source scientific software programs that can simulate broadband (0-100 Hz) ground motions for earthquakes at regional scales. The BBP can run earthquake rupture and wave propagation modeling software to simulate ground motions for well-observed historical earthquakes and to quantify how well the simulated broadband seismograms match the observed seismograms. The BBP can also run simulations for hypothetical earthquakes. In this case, users input an earthquake location and magnitude description, a list of station locations, and a 1D velocity model for the region of interest, and the BBP software then calculates ground motions for the specified stations. The BBP scientific software modules implement kinematic rupture generation, low- and high-frequency seismogram synthesis using wave propagation through 1D layered velocity structures, several ground motion intensity measure calculations, and various ground motion goodness-of-fit tools. These modules are integrated into a software system that provides user-defined, repeatable, calculation of ground-motion seismograms, using multiple alternative ground motion simulation methods, and software utilities to generate tables, plots, and maps. The BBP has been developed over the last five years in a collaborative project involving geoscientists, earthquake engineers, graduate students, and SCEC scientific software developers. The SCEC BBP software released in 2016 can be compiled and run on recent Linux and Mac OS X systems with GNU compilers. It includes five simulation methods, seven simulation regions covering California, Japan, and Eastern North America, and the ability to compare simulation results against empirical ground motion models (aka GMPEs). The latest version includes updated ground motion simulation methods, a suite of new validation metrics and a simplified command line user interface.

  10. Design of a master Fastbus for the data acquisition of the DELPHI external detector. Measurement of the strong interaction coupling constant in the Z neutral boson hadronic decay

    International Nuclear Information System (INIS)

    Chorowicz, V.

    1990-05-01

    The thesis was prepared at the Delphi experiment. The work, performed in the LPNHE-Paris group, consists of two steps: the data acquisition at the Delphi External Detector and the analysis of the hadronic data, in order to extract the coupling constant of the strong interactions at √s = 91 GeV. In the first part of the thesis, the constraints relating to the data acquisition and the Delphi output are discussed. The data acquisition system of the External Detector and the implementation of the AM29000 on the main Fastbus are described. The AM29000 is a RISC type processor, which can support the high frequencies expected from the beam luminosity increase at LEP. This module will replace front end freeing monitor which is presently controlled by a 68020 microprocessor. In the second part of the thesis, the data acquired at Delphi from September to December 1989 is analyzed. The investigation is focused on the hadronic events in order to obtain the Standard Model basic parameter: the Λ QCD , which determines the energy dependence of the strong interactions coupling constant. A method based on the measurement of the energy-energy correlations in the hadronic jets is used and the results are discussed. The Λ QCD value is obtained by fitting the theoretical expected value to the distribution of the energy-energy correlations asymmetry [fr

  11. Clinical prediction models for bronchopulmonary dysplasia: a systematic review and external validation study

    NARCIS (Netherlands)

    Onland, Wes; Debray, Thomas P.; Laughon, Matthew M.; Miedema, Martijn; Cools, Filip; Askie, Lisa M.; Asselin, Jeanette M.; Calvert, Sandra A.; Courtney, Sherry E.; Dani, Carlo; Durand, David J.; Marlow, Neil; Peacock, Janet L.; Pillow, J. Jane; Soll, Roger F.; Thome, Ulrich H.; Truffert, Patrick; Schreiber, Michael D.; van Reempts, Patrick; Vendettuoli, Valentina; Vento, Giovanni; van Kaam, Anton H.; Moons, Karel G.; Offringa, Martin

    2013-01-01

    Bronchopulmonary dysplasia (BPD) is a common complication of preterm birth. Very different models using clinical parameters at an early postnatal age to predict BPD have been developed with little extensive quantitative validation. The objective of this study is to review and validate clinical

  12. Internal and External Validation of a multivariable Model to Define Hospital-Acquired Pneumonia After Esophagectomy

    NARCIS (Netherlands)

    Weijs, Teus J; Seesing, Maarten F J; van Rossum, Peter S N; Koëter, Marijn; van der Sluis, Pieter C; Luyer, Misha D P; Ruurda, Jelle P; Nieuwenhuijzen, Grard A P; van Hillegersberg, Richard

    BACKGROUND: Pneumonia is an important complication following esophagectomy; however, a wide range of pneumonia incidence is reported. The lack of one generally accepted definition prevents valid inter-study comparisons. We aimed to simplify and validate an existing scoring model to define pneumonia

  13. External validation of approaches to prediction of falls during hospital rehabilitation stays and development of a new simpler tool

    Directory of Open Access Journals (Sweden)

    Angela Vratsistas-Curto

    2017-12-01

    Full Text Available Objectives: To test the external validity of 4 approaches to fall prediction in a rehabilitation setting (Predict_FIRST, Ontario Modified STRATIFY (OMS, physiotherapists’ judgement of fall risk (PT_Risk, and falls in the past year (Past_Falls, and to develop and test the validity of a simpler tool for fall prediction in rehabilitation (Predict_CM2. Participants: A total of 300 consecutively-admitted rehabilitation inpatients. Methods: Prospective inception cohort study. Falls during the rehabilitation stay were monitored. Potential predictors were extracted from medical records. Results: Forty-one patients (14% fell during their rehabilitation stay. The external validity, area under the receiver operating characteristic curve (AUC, for predicting future fallers was: 0.71 (95% confidence interval (95% CI: 0.61–0.81 for OMS (Total_Score; 0.66 (95% CI: 0.57–0.74 for Predict_FIRST; 0.65 (95% CI 0.57–0.73 for PT_Risk; and 0.52 for Past_Falls (95% CI: 0.46–0.60. A simple 3-item tool (Predict_CM2 was developed from the most predictive individual items (impaired mobility/transfer ability, impaired cognition, and male sex. The accuracy of Predict_CM2 was 0.73 (95% CI: 0.66–0.81, comparable to OMS (Total_Score (p = 0.52, significantly better than Predict_FIRST (p = 0.04, and Past_Falls (p < 0.001, and approaching significantly better than PT_Risk (p = 0.09. Conclusion: Predict_CM2 is a simpler screening tool with similar accuracy for predicting fallers in rehabilitation to OMS (Total_Score and better accuracy than Predict_FIRST or Past_Falls. External validation of Predict_CM2 is required.

  14. External validation of prognostic models to predict risk of gestational diabetes mellitus in one Dutch cohort: prospective multicentre cohort study.

    Science.gov (United States)

    Lamain-de Ruiter, Marije; Kwee, Anneke; Naaktgeboren, Christiana A; de Groot, Inge; Evers, Inge M; Groenendaal, Floris; Hering, Yolanda R; Huisjes, Anjoke J M; Kirpestein, Cornel; Monincx, Wilma M; Siljee, Jacqueline E; Van 't Zelfde, Annewil; van Oirschot, Charlotte M; Vankan-Buitelaar, Simone A; Vonk, Mariska A A W; Wiegers, Therese A; Zwart, Joost J; Franx, Arie; Moons, Karel G M; Koster, Maria P H

    2016-08-30

     To perform an external validation and direct comparison of published prognostic models for early prediction of the risk of gestational diabetes mellitus, including predictors applicable in the first trimester of pregnancy.  External validation of all published prognostic models in large scale, prospective, multicentre cohort study.  31 independent midwifery practices and six hospitals in the Netherlands.  Women recruited in their first trimester (diabetes mellitus of any type were excluded.  Discrimination of the prognostic models was assessed by the C statistic, and calibration assessed by calibration plots.  3723 women were included for analysis, of whom 181 (4.9%) developed gestational diabetes mellitus in pregnancy. 12 prognostic models for the disorder could be validated in the cohort. C statistics ranged from 0.67 to 0.78. Calibration plots showed that eight of the 12 models were well calibrated. The four models with the highest C statistics included almost all of the following predictors: maternal age, maternal body mass index, history of gestational diabetes mellitus, ethnicity, and family history of diabetes. Prognostic models had a similar performance in a subgroup of nulliparous women only. Decision curve analysis showed that the use of these four models always had a positive net benefit.  In this external validation study, most of the published prognostic models for gestational diabetes mellitus show acceptable discrimination and calibration. The four models with the highest discriminative abilities in this study cohort, which also perform well in a subgroup of nulliparous women, are easy models to apply in clinical practice and therefore deserve further evaluation regarding their clinical impact. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  15. Nonlinear Site Response Validation Studies Using KIK-net Strong Motion Data

    Science.gov (United States)

    Asimaki, D.; Shi, J.

    2014-12-01

    Earthquake simulations are nowadays producing realistic ground motion time-series in the range of engineering design applications. Of particular significance to engineers are simulations of near-field motions and large magnitude events, for which observations are scarce. With the engineering community slowly adopting the use of simulated ground motions, site response models need to be re-evaluated in terms of their capabilities and limitations to 'translate' the simulated time-series from rock surface output to structural analyses input. In this talk, we evaluate three one-dimensional site response models: linear viscoelastic, equivalent linear and nonlinear. We evaluate the performance of the models by comparing predictions to observations at 30 downhole stations of the Japanese network KIK-Net that have recorded several strong events, including the 2011 Tohoku earthquake. Velocity profiles are used as the only input to all models, while additional parameters such as quality factor, density and nonlinear dynamic soil properties are estimated from empirical correlations. We quantify the differences of ground surface predictions and observations in terms of both seismological and engineering intensity measures, including bias ratios of peak ground response and visual comparisons of elastic spectra, and inelastic to elastic deformation ratio for multiple ductility ratios. We observe that PGV/Vs,30 — as measure of strain— is a better predictor of site nonlinearity than PGA, and that incremental nonlinear analyses are necessary to produce reliable estimates of high-frequency ground motion components at soft sites. We finally discuss the implications of our findings on the parameterization of nonlinear amplification factors in GMPEs, and on the extensive use of equivalent linear analyses in probabilistic seismic hazard procedures.

  16. SU-C-BRF-05: Design and Geometric Validation of An Externally and Internally Deformable, Programmable Lung Motion Phantom

    International Nuclear Information System (INIS)

    Cheung, Y; Sawant, A

    2014-01-01

    Purpose: Most clinically-deployed strategies for respiratory motion management in lung radiotherapy (e.g., gating, tracking) use external markers that serve as surrogates for tumor motion. However, typical lung phantoms used to validate these strategies are rigid-exterior+rigid-interior or rigid-exterior+deformable-interior. Neither class adequately represents the human anatomy, which is deformable internally as well as externally. We describe the construction and experimental validation of a more realistic, externally- and internally-deformable, programmable lung phantom. Methods: The outer shell of a commercially-available lung phantom (RS- 1500, RSD Inc.) was used. The shell consists of a chest cavity with a flexible anterior surface, and embedded vertebrae, rib-cage and sternum. A 3-axis platform was programmed with sinusoidal and six patient-recorded lung tumor trajectories. The platform was used to drive a rigid foam ‘diaphragm’ that compressed/decompressed the phantom interior. Experimental characterization comprised of mapping the superior-inferior (SI) and anterior-posterior (AP) trajectories of external and internal radioopaque markers with kV x-ray fluoroscopy and correlating these with optical surface monitoring using the in-room VisionRT system. Results: The phantom correctly reproduced the programmed motion as well as realistic effects such as hysteresis. The reproducibility of marker trajectories over multiple runs for sinusoidal as well as patient traces, as characterized by fluoroscopy, was within 0.4 mm RMS error for internal as well as external markers. The motion trajectories of internal and external markers as measured by fluoroscopy were found to be highly correlated (R=0.97). Furthermore, motion trajectories of arbitrary points on the deforming phantom surface, as recorded by the VisionRT system also showed a high correlation with respect to the fluoroscopically-measured trajectories of internal markers (R=0.92). Conclusion: We have

  17. External validation of the A2SD2 and ISAN scales for predicting infectious respiratory complications of ischaemic stroke.

    Science.gov (United States)

    Ramírez-Moreno, J M; Martínez-Acevedo, M; Cordova, R; Roa, A M; Constantino, A B; Ceberino, D; Muñoz, P

    2016-10-21

    Pneumonia as a complication of stroke is associated with poor outcomes. The A2DS2 and ISAN scales were developed by German and English researchers, respectively, to predict in-hospital stroke-associated pneumonia. We conducted an external validation study of these scales in a series of consecutive patients admitted to our hospital due to ischaemic stroke. These predictive models were applied to a sample of 340 consecutive patients admitted to hospital in 2015 due to stroke. Discrimination was assessed by calculating the area under the ROC curve for diagnostic efficacy. Calibration was assessed using the Hosmer-Lemeshow goodness-of-fit test and graphing the corresponding curve. Logistic regression analysis was performed to determine the independent predictors of respiratory infection secondary to stroke. We included 285 patients, of whom 45 (15.8%) had respiratory infection after stroke according to the study criteria. Mean age was 71.01±12.62 years; men accounted for 177 of the patients (62.1%). Seventy-two patients (25.3%) had signs or symptoms of dysphagia, 42 (14.7%) had atrial fibrillation, and 14 (4.9%) were functionally dependent before stroke; the median NIHSS score was 4 points. Mean scores on A2DS2 and ISAN were 3.25±2.54 and 6.49±3.64, respectively. Our analysis showed that higher A2DS2 scores were associated with an increased risk of infection (OR=1.576; 95% CI: 1.363-1.821); the same was true for ISAN scores (OR=1.350; 95% CI: 1.214-1.501). High scores on A2DS2 and ISAN were found to be a strong predictor of respiratory infection associated with acute stroke in a cohort of consecutive patients with stroke. These easy-to-use scales are promising tools for predicting this complication in routine clinical practice. Copyright © 2016 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  18. External validation of blood eosinophils, FE(NO) and serum periostin as surrogates for sputum eosinophils in asthma.

    Science.gov (United States)

    Wagener, A H; de Nijs, S B; Lutter, R; Sousa, A R; Weersink, E J M; Bel, E H; Sterk, P J

    2015-02-01

    Monitoring sputum eosinophils in asthma predicts exacerbations and improves management of asthma. Thus far, blood eosinophils and FE(NO) show contradictory results in predicting eosinophilic airway inflammation. More recently, serum periostin was proposed as a novel biomarker for eosinophilic inflammation. Quantifying the mutual relationships of blood eosinophils, FE(NO), and serum periostin with sputum eosinophils by external validation in two independent cohorts across various severities of asthma. The first cohort consisted of 110 patients with mild to moderate asthma (external validation cohort). The replication cohort consisted of 37 patients with moderate to severe asthma. Both cohorts were evaluated cross-sectionally. Sputum was induced for the assessment of eosinophils. In parallel, blood eosinophil counts, serum periostin concentrations and FENO were assessed. The diagnostic accuracy of these markers to identify eosinophilic asthma (sputum eosinophils ≥3%) was calculated using receiver operating characteristics area under the curve (ROC AUC). In the external validation cohort, ROC AUC for blood eosinophils was 89% (peosinophilic from non-eosinophilic airway inflammation (ROC AUC=55%, p=0.44). When combining these three variables, no improvement was seen. The diagnostic value of blood eosinophils was confirmed in the replication cohort (ROC AUC 85%, peosinophils had the highest accuracy in the identification of sputum eosinophilia in asthma. The use of blood eosinophils can facilitate individualised treatment and management of asthma. NTR1846 and NTR2364. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  19. Evaluating health inequity interventions: applying a contextual (external) validity framework to programs funded by the Canadian Health Services Research Foundation.

    Science.gov (United States)

    Phillips, Kaye; Müller-Clemm, Werner; Ysselstein, Margaretha; Sachs, Jonathan

    2013-02-01

    Including context in the measurement and evaluation of health in equity interventions is critical to understanding how events that occur in an intervention's environment might contribute to or impede its success. This study adapted and piloted a contextual validity assessment framework on a selection of health inequity-related programs funded by the Canadian Health Services Research Foundation (CHSRF) between 1998 and 2006. The two overarching objectives of this study were (1) to determine the relative amount and quality of attention given to conceptualizing, measuring and validating context within CHSRF funded research final reports related to health-inequity; and (2) to contribute evaluative evidence towards the incorporation of context into the assessment and measurement of health inequity interventions. The study found that of the 42/146 CHSRF programs and projects, judged to be related to health inequity 20 adequately reported on the conceptualization, measurement and validation of context. Amongst these health-inequity related project reports, greatest emphasis was placed on describing the socio-political and economical context over actually measuring and validating contextual evidence. Applying a contextual validity assessment framework was useful for distinguishing between the descriptive (conceptual) versus empirical (measurement and validation) inclusion of documented contextual evidence. Although contextual validity measurement frameworks needs further development, this study contributes insight into identifying funded research related to health inequities and preliminary criteria for assessing interventions targeted at specific populations and jurisdictions. This study also feeds a larger critical dialogue (albeit beyond the scope of this study) regarding the relevance and utility of using evaluative techniques for understanding how specific external conditions support or impede the successful implementation of health inequity interventions. Copyright

  20. The impact of crowd noise on officiating in Muay Thai: achieving external validity in an experimental setting

    Directory of Open Access Journals (Sweden)

    Tony D Myers

    2012-09-01

    Full Text Available Numerous factors have been proposed to explain the home advantage in sport. Several authors have suggested that a partisan home crowd enhances home advantage and that this is at least in part a consequence of their influence on officiating. However, while experimental studies examining this phenomenon have high levels of internal validity (since only the ‘crowd noise’ intervention is allowed to vary, they suffer from a lack of external validity, with decision-making in a laboratory setting typically bearing little resemblance to decision-making in live sports settings. Conversely, observational and quasi-experimental studies with high levels of external validity suffer from low levels of internal validity as countless factors besides crowd noise vary. The present study provides a unique opportunity to address these criticisms, by conducting a controlled experiment on the impact of crowd noise on officiating in a live tournament setting. Seventeen qualified judges officiated on thirty Thai boxing bouts in a live international tournament setting featuring ‘home’ and ‘away’ boxers. In each bout, judges were randomised into a ‘noise’ (live sound or ‘no crowd noise’ (noise cancelling headphones and white noise condition, resulting in 59 judgements in the ‘no crowd noise’ and 61 in the ‘crowd noise’ condition. The results provide the first experimental evidence of the impact of live crowd noise on officials in sport. A cross-classified statistical model indicated that crowd noise had a statistically significant impact, equating to just over half a point per bout (in the context of five round bouts with the ‘ten point must’ scoring system shared with professional boxing. The practical significance of the findings, their implications for officiating and for the future conduct of crowd noise studies are discussed.

  1. The impact of crowd noise on officiating in muay thai: achieving external validity in an experimental setting.

    Science.gov (United States)

    Myers, Tony; Balmer, Nigel

    2012-01-01

    Numerous factors have been proposed to explain the home advantage in sport. Several authors have suggested that a partisan home crowd enhances home advantage and that this is at least in part a consequence of their influence on officiating. However, while experimental studies examining this phenomenon have high levels of internal validity (since only the "crowd noise" intervention is allowed to vary), they suffer from a lack of external validity, with decision-making in a laboratory setting typically bearing little resemblance to decision-making in live sports settings. Conversely, observational and quasi-experimental studies with high levels of external validity suffer from low levels of internal validity as countless factors besides crowd noise vary. The present study provides a unique opportunity to address these criticisms, by conducting a controlled experiment on the impact of crowd noise on officiating in a live tournament setting. Seventeen qualified judges officiated on thirty Thai boxing bouts in a live international tournament setting featuring "home" and "away" boxers. In each bout, judges were randomized into a "noise" (live sound) or "no crowd noise" (noise-canceling headphones and white noise) condition, resulting in 59 judgments in the "no crowd noise" and 61 in the "crowd noise" condition. The results provide the first experimental evidence of the impact of live crowd noise on officials in sport. A cross-classified statistical model indicated that crowd noise had a statistically significant impact, equating to just over half a point per bout (in the context of five round bouts with the "10-point must" scoring system shared with professional boxing). The practical significance of the findings, their implications for officiating and for the future conduct of crowd noise studies are discussed.

  2. Sample size calculation to externally validate scoring systems based on logistic regression models.

    Directory of Open Access Journals (Sweden)

    Antonio Palazón-Bru

    Full Text Available A sample size containing at least 100 events and 100 non-events has been suggested to validate a predictive model, regardless of the model being validated and that certain factors can influence calibration of the predictive model (discrimination, parameterization and incidence. Scoring systems based on binary logistic regression models are a specific type of predictive model.The aim of this study was to develop an algorithm to determine the sample size for validating a scoring system based on a binary logistic regression model and to apply it to a case study.The algorithm was based on bootstrap samples in which the area under the ROC curve, the observed event probabilities through smooth curves, and a measure to determine the lack of calibration (estimated calibration index were calculated. To illustrate its use for interested researchers, the algorithm was applied to a scoring system, based on a binary logistic regression model, to determine mortality in intensive care units.In the case study provided, the algorithm obtained a sample size with 69 events, which is lower than the value suggested in the literature.An algorithm is provided for finding the appropriate sample size to validate scoring systems based on binary logistic regression models. This could be applied to determine the sample size in other similar cases.

  3. The Subaxial Cervical Spine Injury Classification System: an external agreement validation study

    NARCIS (Netherlands)

    Middendorp, J.J. van; Audige, L.; Bartels, R.H.M.A.; Bolger, C.; Deverall, H.; Dhoke, P.; Diekerhof, C.H.; Govaert, G.A.; Guimera, V.; Koller, H.; Morris, S.A.; Setiobudi, T.; Hosman, A.J.F.

    2013-01-01

    BACKGROUND CONTEXT: In 2007, the Subaxial Cervical Spine Injury Classification (SLIC) system was introduced demonstrating moderate reliability in an internal validation study. PURPOSE: To assess the agreement on the SLIC system using clinical data from a spinal trauma population and whether the SLIC

  4. The Subaxial Cervical Spine Injury Classification System : an external agreement validation study

    NARCIS (Netherlands)

    van Middendorp, Joost J.; Audige, Laurent; Bartels, Ronald H.; Bolger, Ciaran; Deverall, Hamish; Dhoke, Priyesh; Diekerhof, Carel H.; Govaert, Geertje A. M.; Guimera, Vicente; Koller, Heiko; Morris, Stephen A. C.; Setiobudi, Tony; Hosman, Allard J. F.

    BACKGROUND CONTEXT: In 2007, the Subaxial Cervical Spine Injury Classification (SLIC) system was introduced demonstrating moderate reliability in an internal validation study. PURPOSE: To assess the agreement on the SLIC system using clinical data from a spinal trauma population and whether the SLIC

  5. Parametric oesophageal multiple swallow scintigraphy for validation of dysphageal symptoms during external beam irradiation of mediastinal tumours

    Energy Technology Data Exchange (ETDEWEB)

    Brandt-Mainz, K.; Eising, E.G.; Bockisch, A. [Essen Univ. (Gesamthochschule) (Germany). Klinik und Poliklinik fuer Nuklearmedizin; Mallek, D. von; Poettgen, C.; Stuschke, M.; Sack, H. [Klinik und Poliklinik fuer Strahlentherapie, Universitaetsklinikum Essen (Germany)

    2001-03-01

    The aim of the study was to evaluate dysphageal symptoms and to measure the effect of local analgesic treatment using parametric oesophageal multiple swallow scintigraphy (PES) during external beam irradiation of the mediastinal region. Fifteen patients (most with lung cancer) with dysphagia grade II underwent PES during external beam radiotherapy of the mediastinum before and after application of local analgesics. Dynamic parametric condensed images were recorded. The intensity of clinical symptoms was correlated with the emptying rate at 10 s (ER-10 s) and the mean transit time (MTT). Visual analysis of the images was performed and the results were correlated with the fields of irradiation portals. Of the 15 patients, 12 showed a correlation between irradiation portals and the region of oesophageal motility disorder. Concordant results of clinical symptoms and PES data were found. In nine patients with a decrease in dysphagia following local analgesia, an increase in mean ER-10 s and a decrease in MTT were observed. In three patients with deterioration in clinical symptoms after analgesic treatment, a similar decrease in mean ER-10 s was found, though MTT remained constant. In three patients with normal values, motility disorders were detected in the dynamic study. In conclusion, PES was found to be a sensitive tool for the validation of dysphageal symptoms in patients during external beam irradiation of mediastinal tumours and for the evaluation and quantification of the efficacy of local analgesic treatment. Additional visual analysis of the dynamic study is helpful in diagnosing minimal disorders. (orig.)

  6. Parametric oesophageal multiple swallow scintigraphy for validation of dysphageal symptoms during external beam irradiation of mediastinal tumours

    International Nuclear Information System (INIS)

    Brandt-Mainz, K.; Eising, E.G.; Bockisch, A.

    2001-01-01

    The aim of the study was to evaluate dysphageal symptoms and to measure the effect of local analgesic treatment using parametric oesophageal multiple swallow scintigraphy (PES) during external beam irradiation of the mediastinal region. Fifteen patients (most with lung cancer) with dysphagia grade II underwent PES during external beam radiotherapy of the mediastinum before and after application of local analgesics. Dynamic parametric condensed images were recorded. The intensity of clinical symptoms was correlated with the emptying rate at 10 s (ER-10 s) and the mean transit time (MTT). Visual analysis of the images was performed and the results were correlated with the fields of irradiation portals. Of the 15 patients, 12 showed a correlation between irradiation portals and the region of oesophageal motility disorder. Concordant results of clinical symptoms and PES data were found. In nine patients with a decrease in dysphagia following local analgesia, an increase in mean ER-10 s and a decrease in MTT were observed. In three patients with deterioration in clinical symptoms after analgesic treatment, a similar decrease in mean ER-10 s was found, though MTT remained constant. In three patients with normal values, motility disorders were detected in the dynamic study. In conclusion, PES was found to be a sensitive tool for the validation of dysphageal symptoms in patients during external beam irradiation of mediastinal tumours and for the evaluation and quantification of the efficacy of local analgesic treatment. Additional visual analysis of the dynamic study is helpful in diagnosing minimal disorders. (orig.)

  7. External validation of the use of vignettes in cross-country health studies

    DEFF Research Database (Denmark)

    Datta Gupta, Nabanita; Kristensen, Nicolai; Pozzoli, Dario

    2010-01-01

    Cross-country comparisons of subjective assessments are rendered difficult if not impossible because of sub-population specific response style. To correct for this, the use of vignettes has become increasingly popular, notably within cross-country health studies. However, the validity of vignette...... and vignettes. Our results indicate that the assumption of RC is not innocuous and that our extended model relaxing this assumption improves the fit and significantly changes the cross-country rankings of health vis-a-vis the standard Chopit model.......Cross-country comparisons of subjective assessments are rendered difficult if not impossible because of sub-population specific response style. To correct for this, the use of vignettes has become increasingly popular, notably within cross-country health studies. However, the validity of vignettes...

  8. External Validation of the Use of Vignettes in Cross-Country Health Studies

    DEFF Research Database (Denmark)

    Datta Gupta, Nabanita; Kristensen, Nicolai; Pozzoli, Dario

    Cross-country comparisons of subjective assessments are rendered difficult if not impossible because of sub-population specific response style. To correct for this, the use of vignettes has become increasingly popular, notably within cross-country health studies. However, the validity of vignette...... and vignettes. Our results indicate that the assumption of RC is not innocuous and that our extended model relaxing this assumption improves the fit and significantly changes the cross-country rankings of health vis-à-vis the standard Chopit model.......Cross-country comparisons of subjective assessments are rendered difficult if not impossible because of sub-population specific response style. To correct for this, the use of vignettes has become increasingly popular, notably within cross-country health studies. However, the validity of vignettes...

  9. External validation of the use of vignettes in cross-country health studies

    DEFF Research Database (Denmark)

    Gupta, Nabanita Datta; Kristensen, Nicolai; Pozzoli, Dario

    Cross-country comparisons of subjective assessments are rendered difficult if not impossible because of sub-population specific response style. To correct for this, the use of vignettes has become increasingly popular, notably within cross-country health studies. However, the validity of vignette...... and vignettes. Our results indicate that the assumption of RC is not innocous and that our extended model relaxing this assumption improves the fit and significantly changes the cross-country rankings of health vis-\\'{a}-vis the standard Chopit model.......Cross-country comparisons of subjective assessments are rendered difficult if not impossible because of sub-population specific response style. To correct for this, the use of vignettes has become increasingly popular, notably within cross-country health studies. However, the validity of vignettes...

  10. The predictive and external validity of the STarT Back Tool in Danish primary care.

    Science.gov (United States)

    Morsø, Lars; Kent, Peter; Albert, Hanne B; Hill, Jonathan C; Kongsted, Alice; Manniche, Claus

    2013-08-01

    The STarT Back Tool (SBT) was recently translated into Danish and its concurrent validity described. This study tested the predictive validity of the Danish SBT. Danish primary care patients (n = 344) were compared to a UK cohort. SBT subgroup validity for predicting high activity limitation at 3 months' follow-up was assessed using descriptive proportions, relative risks, AUC and odds ratios. The SBT had a statistically similar predictive ability in Danish primary care as in UK primary care. Unadjusted relative risks for poor clinical outcome on activity limitation in the Danish cohort were 2.4 (1.7-3.4) for the medium-risk subgroup and 2.8 (1.8-3.8) for the high-risk subgroup versus 3.1 (2.5-3.9) and 4.5 (3.6-5.6) for the UK cohort. Adjusting for confounders appeared to explain the lower predictive ability of the Danish high-risk group. The Danish SBT distinguished between low- and medium-risk subgroups with a similar predictive ability of the UK SBT. That distinction is useful information for informing patients about their expected prognosis and may help guiding clinicians' choice of treatment. However, cross-cultural differences in the SBT psychosocial subscale may reduce the predictive ability of the high-risk subgroup in Danish primary care.

  11. Development, external validation and clinical usefulness of a practical prediction model for radiation-induced dysphagia in lung cancer patients

    International Nuclear Information System (INIS)

    Dehing-Oberije, Cary; De Ruysscher, Dirk; Petit, Steven; Van Meerbeeck, Jan; Vandecasteele, Katrien; De Neve, Wilfried; Dingemans, Anne Marie C.; El Naqa, Issam; Deasy, Joseph; Bradley, Jeff; Huang, Ellen; Lambin, Philippe

    2010-01-01

    Introduction: Acute dysphagia is a distressing dose-limiting toxicity occurring frequently during concurrent chemo-radiation or high-dose radiotherapy for lung cancer. It can lead to treatment interruptions and thus jeopardize survival. Although a number of predictive factors have been identified, it is still not clear how these could offer assistance for treatment decision making in daily clinical practice. Therefore, we have developed and validated a nomogram to predict this side-effect. In addition, clinical usefulness was assessed by comparing model predictions to physicians' predictions. Materials and methods: Clinical data from 469 inoperable lung cancer patients, treated with curative intent, were collected prospectively. A prediction model for acute radiation-induced dysphagia was developed. Model performance was evaluated by the c-statistic and assessed using bootstrapping as well as two external datasets. In addition, a prospective study was conducted comparing model to physicians' predictions in 138 patients. Results: The final multivariate model consisted of age, gender, WHO performance status, mean esophageal dose (MED), maximum esophageal dose (MAXED) and overall treatment time (OTT). The c-statistic, assessed by bootstrapping, was 0.77. External validation yielded an AUC of 0.94 on the Ghent data and 0.77 on the Washington University St. Louis data for dysphagia ≥ grade 3. Comparing model predictions to the physicians' predictions resulted in an AUC of 0.75 versus 0.53, respectively. Conclusions: The proposed model performed well was successfully validated and demonstrated the ability to predict acute severe dysphagia remarkably better than the physicians. Therefore, this model could be used in clinical practice to identify patients at high or low risk.

  12. Validation of strong-motion stochastic model using observed ground motion records in north-east India

    Directory of Open Access Journals (Sweden)

    Dipok K. Bora

    2016-03-01

    Full Text Available We focused on validation of applicability of semi-empirical technique (spectral models and stochastic simulation for the estimation of ground-motion characteristics in the northeastern region (NER of India. In the present study, it is assumed that the point source approximation in far field is valid. The one-dimensional stochastic point source seismological model of Boore (1983 (Boore, DM. 1983. Stochastic simulation of high frequency ground motions based on seismological models of the radiated spectra. Bulletin of Seismological Society of America, 73, 1865–1894. is used for modelling the acceleration time histories. Total ground-motion records of 30 earthquakes of magnitudes lying between MW 4.2 and 6.2 in NER India from March 2008 to April 2013 are used for this study. We considered peak ground acceleration (PGA and pseudospectral acceleration (response spectrum amplitudes with 5% damping ratio at three fundamental natural periods, namely: 0.3, 1.0, and 3.0 s. The spectral models, which work well for PGA, overestimate the pseudospectral acceleration. It seems that there is a strong influence of local site amplification and crustal attenuation (kappa, which control spectral amplitudes at different frequencies. The results would allow analysing regional peculiarities of ground-motion excitation and propagation and updating seismic hazard assessment, both the probabilistic and deterministic approaches.

  13. Development of strong-sense validation benchmarks for the fluoride salt-cooled high-temperature reactor

    International Nuclear Information System (INIS)

    Blandford, E. D.

    2012-01-01

    The Fluoride salt-cooled High-temperature Reactor (FHR) is a class of reactor concepts currently under development for the U. S. Dept. of Energy. The FHR is defined as a Generation IV reactor that features low-pressure liquid fluoride salt cooling, coated-particle fuel, a high-temperature power cycle, and fully passive decay heat rejection. Recent experimental work using simulant fluids have been performed to demonstrate key 'proof of principle' FHR concepts and have helped inform the reactor design process. An important element of developing FHR technology is to sufficiently validate the predictive accuracy of the computer codes used to model system response. This paper presents a set of thermal-hydraulics experiments, defined as Strong-Sense Benchmarks (SSB's), which will help establish the FHR validation domain for simulant fluid suitability. These SSB's are more specifically designed to investigate single-phase natural circulation which is the dominant mode of FHR decay heat removal during off-normal conditions. SSB s should be viewed as engineering reference standards and differ from traditional confirmatory experiments in the sense that they are more focused on fundamental physics as opposed to reproducing high levels of physical similarity with the prototypical design. (authors)

  14. Opportunistic screening for osteoporosis on routine computed tomography? An external validation study

    Energy Technology Data Exchange (ETDEWEB)

    Buckens, Constantinus F. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Universitair Medisch Centrum Utrecht, Department of Radiology, Utrecht (Netherlands); Dijkhuis, Gawein; Jong, Pim A. de [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Keizer, Bart de [University Medical Center Utrecht, Department of Nuclear Medicine, Utrecht (Netherlands); Verhaar, Harald J. [University Medical Center Utrecht, Department of Geriatric Medicine, Utrecht (Netherlands)

    2015-07-15

    Opportunistic screening for osteoporosis using computed tomography (CT) examinations that happen to visualise the spine can be used to identify patients with osteoporosis. We sought to verify the diagnostic performance of vertebral Hounsfield unit (HU) measurements on routine CT examinations for diagnosing osteoporosis in a separate, external population. Consecutive patients who underwent a CT examination of the chest or abdomen and had also received a dual-energy X-ray absorptiometry (DXA) test were retrospectively included. CTs were evaluated for vertebral fractures and vertebral attenuation (density) values were measured. Diagnostic performance measures and the area under the receiver operator characteristics curve (AUC) for diagnosing osteoporosis were calculated. Three hundred and two patients with a mean age of 57.9 years were included, of which 82 (27 %) had osteoporosis according to DXA and 65 (22 %) had vertebral fractures. The diagnostic performance for vertebral HU measurements was modest, with a maximal AUC of 0.74 (0.68 - 0.80). At that optimal threshold the sensitivity was 62 % (51 - 72 %) and the specificity was 79 % (74 - 84 %). We confirmed that simple trabecular vertebral density measurements on routine CT contain diagnostic information related to bone mineral density as measured by DXA, albeit with substantially lower diagnostic accuracy than previously reported. (orig.)

  15. Opportunistic screening for osteoporosis on routine computed tomography? An external validation study

    International Nuclear Information System (INIS)

    Buckens, Constantinus F.; Dijkhuis, Gawein; Jong, Pim A. de; Keizer, Bart de; Verhaar, Harald J.

    2015-01-01

    Opportunistic screening for osteoporosis using computed tomography (CT) examinations that happen to visualise the spine can be used to identify patients with osteoporosis. We sought to verify the diagnostic performance of vertebral Hounsfield unit (HU) measurements on routine CT examinations for diagnosing osteoporosis in a separate, external population. Consecutive patients who underwent a CT examination of the chest or abdomen and had also received a dual-energy X-ray absorptiometry (DXA) test were retrospectively included. CTs were evaluated for vertebral fractures and vertebral attenuation (density) values were measured. Diagnostic performance measures and the area under the receiver operator characteristics curve (AUC) for diagnosing osteoporosis were calculated. Three hundred and two patients with a mean age of 57.9 years were included, of which 82 (27 %) had osteoporosis according to DXA and 65 (22 %) had vertebral fractures. The diagnostic performance for vertebral HU measurements was modest, with a maximal AUC of 0.74 (0.68 - 0.80). At that optimal threshold the sensitivity was 62 % (51 - 72 %) and the specificity was 79 % (74 - 84 %). We confirmed that simple trabecular vertebral density measurements on routine CT contain diagnostic information related to bone mineral density as measured by DXA, albeit with substantially lower diagnostic accuracy than previously reported. (orig.)

  16. External validation of a measurement tool to assess systematic reviews (AMSTAR.

    Directory of Open Access Journals (Sweden)

    Beverley J Shea

    Full Text Available BACKGROUND: Thousands of systematic reviews have been conducted in all areas of health care. However, the methodological quality of these reviews is variable and should routinely be appraised. AMSTAR is a measurement tool to assess systematic reviews. METHODOLOGY: AMSTAR was used to appraise 42 reviews focusing on therapies to treat gastro-esophageal reflux disease, peptic ulcer disease, and other acid-related diseases. Two assessors applied the AMSTAR to each review. Two other assessors, plus a clinician and/or methodologist applied a global assessment to each review independently. CONCLUSIONS: The sample of 42 reviews covered a wide range of methodological quality. The overall scores on AMSTAR ranged from 0 to 10 (out of a maximum of 11 with a mean of 4.6 (95% CI: 3.7 to 5.6 and median 4.0 (range 2.0 to 6.0. The inter-observer agreement of the individual items ranged from moderate to almost perfect agreement. Nine items scored a kappa of >0.75 (95% CI: 0.55 to 0.96. The reliability of the total AMSTAR score was excellent: kappa 0.84 (95% CI: 0.67 to 1.00 and Pearson's R 0.96 (95% CI: 0.92 to 0.98. The overall scores for the global assessment ranged from 2 to 7 (out of a maximum score of 7 with a mean of 4.43 (95% CI: 3.6 to 5.3 and median 4.0 (range 2.25 to 5.75. The agreement was lower with a kappa of 0.63 (95% CI: 0.40 to 0.88. Construct validity was shown by AMSTAR convergence with the results of the global assessment: Pearson's R 0.72 (95% CI: 0.53 to 0.84. For the AMSTAR total score, the limits of agreement were -0.19+/-1.38. This translates to a minimum detectable difference between reviews of 0.64 'AMSTAR points'. Further validation of AMSTAR is needed to assess its validity, reliability and perceived utility by appraisers and end users of reviews across a broader range of systematic reviews.

  17. Predicting AKI in emergency admissions: an external validation study of the acute kidney injury prediction score (APS).

    Science.gov (United States)

    Hodgson, L E; Dimitrov, B D; Roderick, P J; Venn, R; Forni, L G

    2017-03-08

    Hospital-acquired acute kidney injury (HA-AKI) is associated with a high risk of mortality. Prediction models or rules may identify those most at risk of HA-AKI. This study externally validated one of the few clinical prediction rules (CPRs) derived in a general medicine cohort using clinical information and data from an acute hospitals electronic system on admission: the acute kidney injury prediction score (APS). External validation in a single UK non-specialist acute hospital (2013-2015, 12 554 episodes); four cohorts: adult medical and general surgical populations, with and without a known preadmission baseline serum creatinine (SCr). Performance assessed by discrimination using area under the receiver operating characteristic curves (AUCROC) and calibration. HA-AKI incidence within 7 days (kidney disease: improving global outcomes (KDIGO) change in SCr) was 8.1% (n=409) of medical patients with known baseline SCr, 6.6% (n=141) in those without a baseline, 4.9% (n=204) in surgical patients with baseline and 4% (n=49) in those without. Across the four cohorts AUCROC were: medical with known baseline 0.65 (95% CIs 0.62 to 0.67) and no baseline 0.71 (0.67 to 0.75), surgical with baseline 0.66 (0.62 to 0.70) and no baseline 0.68 (0.58 to 0.75). For calibration, in medicine and surgical cohorts with baseline SCr, Hosmer-Lemeshow p values were non-significant, suggesting acceptable calibration. In the medical cohort, at a cut-off of five points on the APS to predict HA-AKI, positive predictive value was 16% (13-18%) and negative predictive value 94% (93-94%). Of medical patients with HA-AKI, those with an APS ≥5 had a significantly increased risk of death (28% vs 18%, OR 1.8 (95% CI 1.1 to 2.9), p=0.015). On external validation the APS on admission shows moderate discrimination and acceptable calibration to predict HA-AKI and may be useful as a severity marker when HA-AKI occurs. Harnessing linked data from primary care may be one way to achieve more accurate

  18. The development and validation of dried blood spots for external quality assurance of syphilis serology

    Directory of Open Access Journals (Sweden)

    Smit Pieter W

    2013-02-01

    Full Text Available Abstract Background Syphilis causes up to 1,500,000 congenital syphilis cases annually. These could be prevented if all pregnant women were screened, and those with syphilis treated with a single dose of penicillin before 28 weeks gestation. In recent years, rapid point-of-care tests have allowed greater access to syphilis screening, especially in rural or remote areas, but the lack of quality assurance of rapid testing has been a concern. We determined the feasibility of using dried blood spots (DBS as specimens for quality assurance of syphilis serological assays. Methods We developed DBS extraction protocols for use with Treponema pallidum particle agglutination assay (TPPA, Treponema pallidum haemagglutination assay (TPHA and an enzyme immunoassay (EIA and compared the results with those using matching plasma samples from the same patient. Results Since DBS samples showed poor performance with TPHA and EIA (TPHA sensitivity was 50.5% (95% confidence interval: 39.9–61.2% and EIA specificity was 50.4% (95% CI: 43.7–57.1%, only the DBS TPPA was used in the final evaluation. DBS TPPA showed an sensitivity of 95.5% (95% CI: 91.3–98.0% and a specificity of 99.0% (95% CI: 98.1–99.5% compared to TPPA using plasma samples as a reference. Conclusion DBS samples can be recommended for use with TPPA, and may be of value for external quality assurance of point-of-care syphilis testing.

  19. External validation of the clinical dehydration scale for children with acute gastroenteritis.

    Science.gov (United States)

    Bailey, Benoit; Gravel, Jocelyn; Goldman, Ran D; Friedman, Jeremy N; Parkin, Patricia C

    2010-06-01

    The objective was to validate the clinical dehydration scale (CDS) for children with gastroenteritis in a different pediatric emergency department (ED) from where it was initially derived and validated. A prospective cohort study was performed in a tertiary care pediatric ED over a 1-year period. A sample of triage nurses were trained in applying the CDS. The CDS consists of four clinical characteristics (general appearance, eyes, mucous membranes, and tears), each of which are scored 0, 1, or 2 for a total score of 0 to 8, with 0 representing no dehydration; 1 to 4, some dehydration; and 5 to 8, moderate/severe dehydration. Children 1 month to 5 years of age with vomiting and/or diarrhea who had the CDS documented at triage and a final diagnosis of gastroenteritis, gastritis, or enteritis were enrolled. Exclusion criteria included a chronic disease, treatment with intravenous (IV) rehydration within the previous 24 hours, visit to the ED for the same illness in the 7 days prior to arrival, and diarrhea of more than 10 days' duration. The primary outcome was the length of stay (LOS) in the ED from the time of seeing a physician to discharge, analyzed with a Kruskal-Wallis test. From April 2008 to March 2009, 150 patients with a mean (+/-SD) age of 22 (+/-14) months (range = 4 months to 4 years) were enrolled. Fifty-six patients had no dehydration, 74 had some dehydration, and 20 had moderate/severe dehydration. The median LOS in the ED after being seen by a physician was significantly longer as children appeared more dehydrated according to the CDS: 54 minutes (interquartile range [IQR] = 26-175 minutes), 128 minutes (IQR = 25-334 minutes), and 425 minutes (IQR = 218-673 minutes) for the no, some, and moderate/severe dehydration groups, respectively (p children with gastroenteritis in a different pediatric center than the original one where it was developed. It is a good predictor of LOS in the ED after being seen by a physician. (c) 2010 by the Society for

  20. The combination of energy-dependent internal adaptation mechanisms and external factors enables Listeria monocytogenes to express a strong starvation survival response during multiple-nutrient starvation.

    Science.gov (United States)

    Lungu, Bwalya; Saldivar, Joshua C; Story, Robert; Ricke, Steven C; Johnson, Michael G

    2010-05-01

    of cells and external nutrients/factors enables L. monocytogenes to express a strong SSR.

  1. External Validation and Optimization of International Consensus Clinical Target Volumes for Adjuvant Radiation Therapy in Bladder Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, Abhinav V. [Department of Radiation and Cellular Oncology, University of Chicago Pritzker School of Medicine, Chicago, Illinois (United States); Christodouleas, John P. [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Wu, Tianming [Department of Radiation and Cellular Oncology, University of Chicago Pritzker School of Medicine, Chicago, Illinois (United States); Smith, Norman D.; Steinberg, Gary D. [Section of Urology, Department of Surgery, University of Chicago Pritzker School of Medicine, Chicago, Illinois (United States); Liauw, Stanley L., E-mail: sliauw@radonc.uchicago.edu [Department of Radiation and Cellular Oncology, University of Chicago Pritzker School of Medicine, Chicago, Illinois (United States)

    2017-03-15

    Purpose: International consensus (IC) clinical target volumes (CTVs) have been proposed to standardize radiation field design in the treatment of patients at high risk of locoregional failure (LRF) after radical cystectomy. The purpose of this study was to externally validate the IC CTVs in a cohort of postsurgical patients followed up for LRF and identify revisions that might improve the IC CTVs' performance. Methods and Materials: Among 334 patients with pT3 to pT4 bladder cancer treated with radical cystectomy, LRF developed in 58 (17%), of whom 52 had computed tomography scans available for review. Images with LRF were exported into a treatment planning system, and IC CTVs were contoured and evaluated for adequacy of coverage of each LRF with respect to both the patient and each of 6 pelvic subsites: common iliac (CI) region, obturator region (OR), external and internal iliac region, presacral region, cystectomy bed, or other pelvic site. Revisions to the IC contours were proposed based on the findings. Results: Of the 52 patients with documented LRF, 13 (25%) had LRFs that were outside of the IC CTV involving 17 pelvic subsites: 5 near the CI CTV, 5 near the OR CTV, 1 near the external and internal iliac region, and 6 near the cystectomy bed. The 5 CI failures were located superior to the CTV, and the 5 OR failures were located medial to the CTV. Increasing the superior boundary of the CI to a vessel-based definition of the aortic bifurcation, as well as increasing the medial extension of the OR by an additional 9 mm, decreased the number of patients with LRF outside of the IC CTV to 7 (13%). Conclusions: Modified IC CTVs inclusive of a slight adjustment superiorly for the CI region and medially for the OR may reduce the risk of pelvic failure in patients treated with adjuvant radiation therapy.

  2. Development and external multicenter validation of Chinese Prostate Cancer Consortium prostate cancer risk calculator for initial prostate biopsy.

    Science.gov (United States)

    Chen, Rui; Xie, Liping; Xue, Wei; Ye, Zhangqun; Ma, Lulin; Gao, Xu; Ren, Shancheng; Wang, Fubo; Zhao, Lin; Xu, Chuanliang; Sun, Yinghao

    2016-09-01

    Substantial differences exist in the relationship of prostate cancer (PCa) detection rate and prostate-specific antigen (PSA) level between Western and Asian populations. Classic Western risk calculators, European Randomized Study for Screening of Prostate Cancer Risk Calculator, and Prostate Cancer Prevention Trial Risk Calculator, were shown to be not applicable in Asian populations. We aimed to develop and validate a risk calculator for predicting the probability of PCa and high-grade PCa (defined as Gleason Score sum 7 or higher) at initial prostate biopsy in Chinese men. Urology outpatients who underwent initial prostate biopsy according to the inclusion criteria were included. The multivariate logistic regression-based Chinese Prostate Cancer Consortium Risk Calculator (CPCC-RC) was constructed with cases from 2 hospitals in Shanghai. Discriminative ability, calibration and decision curve analysis were externally validated in 3 CPCC member hospitals. Of the 1,835 patients involved, PCa was identified in 338/924 (36.6%) and 294/911 (32.3%) men in the development and validation cohort, respectively. Multivariate logistic regression analyses showed that 5 predictors (age, logPSA, logPV, free PSA ratio, and digital rectal examination) were associated with PCa (Model 1) or high-grade PCa (Model 2), respectively. The area under the curve of Model 1 and Model 2 was 0.801 (95% CI: 0.771-0.831) and 0.826 (95% CI: 0.796-0.857), respectively. Both models illustrated good calibration and substantial improvement in decision curve analyses than any single predictors at all threshold probabilities. Higher predicting accuracy, better calibration, and greater clinical benefit were achieved by CPCC-RC, compared with European Randomized Study for Screening of Prostate Cancer Risk Calculator and Prostate Cancer Prevention Trial Risk Calculator in predicting PCa. CPCC-RC performed well in discrimination and calibration and decision curve analysis in external validation compared

  3. External validation of the Cardiff model of information sharing to reduce community violence: natural experiment.

    Science.gov (United States)

    Boyle, Adrian A; Snelling, Katrina; White, Laura; Ariel, Barak; Ashelford, Lawrence

    2013-12-01

    Community violence is a substantial problem for the NHS. Information sharing of emergency department data with community safety partnerships (CSP) has been associated with substantial reductions in assault attendances in emergency departments supported by academic institutions. We sought to validate these findings in a setting not supported by a public health or academic structure. We instituted anonymous data sharing with the police to reduce community violence, and increased involvement with the local CSP. We measured the effectiveness of this approach with routinely collected data at the emergency department and the police. We used police data from 2009, and emergency department data from 2000. Initially, the number of assault patients requiring emergency department treatment rose after we initiated data sharing. After improving the data flows, the number of assault patients fell back to the predata-sharing level. There was no change in the number of hospital admissions during the study period. There were decreases in the numbers of violent crimes against the person, with and without injury, recorded by the police. We have successfully implemented data sharing in our institution without the support of an academic institution. This has been associated with reductions in violent crime, but it is not clear whether this association is causal.

  4. External validation of structure-biodegradation relationship (SBR) models for predicting the biodegradability of xenobiotics.

    Science.gov (United States)

    Devillers, J; Pandard, P; Richard, B

    2013-01-01

    Biodegradation is an important mechanism for eliminating xenobiotics by biotransforming them into simple organic and inorganic products. Faced with the ever growing number of chemicals available on the market, structure-biodegradation relationship (SBR) and quantitative structure-biodegradation relationship (QSBR) models are increasingly used as surrogates of the biodegradation tests. Such models have great potential for a quick and cheap estimation of the biodegradation potential of chemicals. The Estimation Programs Interface (EPI) Suite™ includes different models for predicting the potential aerobic biodegradability of organic substances. They are based on different endpoints, methodologies and/or statistical approaches. Among them, Biowin 5 and 6 appeared the most robust, being derived from the largest biodegradation database with results obtained only from the Ministry of International Trade and Industry (MITI) test. The aim of this study was to assess the predictive performances of these two models from a set of 356 chemicals extracted from notification dossiers including compatible biodegradation data. Another set of molecules with no more than four carbon atoms and substituted by various heteroatoms and/or functional groups was also embodied in the validation exercise. Comparisons were made with the predictions obtained with START (Structural Alerts for Reactivity in Toxtree). Biowin 5 and Biowin 6 gave satisfactorily prediction results except for the prediction of readily degradable chemicals. A consensus model built with Biowin 1 allowed the diminution of this tendency.

  5. Modification and validation of an analytical source model for external beam radiotherapy Monte Carlo dose calculations

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, Scott E., E-mail: sedavids@utmb.edu [Radiation Oncology, The University of Texas Medical Branch, Galveston, Texas 77555 (United States); Cui, Jing [Radiation Oncology, University of Southern California, Los Angeles, California 90033 (United States); Kry, Stephen; Ibbott, Geoffrey S.; Followill, David S. [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Deasy, Joseph O. [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York 10065 (United States); Vicic, Milos [Department of Applied Physics, University of Belgrade, Belgrade 11000 (Serbia); White, R. Allen [Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

    2016-08-15

    Purpose: A dose calculation tool, which combines the accuracy of the dose planning method (DPM) Monte Carlo code and the versatility of a practical analytical multisource model, which was previously reported has been improved and validated for the Varian 6 and 10 MV linear accelerators (linacs). The calculation tool can be used to calculate doses in advanced clinical application studies. One shortcoming of current clinical trials that report dose from patient plans is the lack of a standardized dose calculation methodology. Because commercial treatment planning systems (TPSs) have their own dose calculation algorithms and the clinical trial participant who uses these systems is responsible for commissioning the beam model, variation exists in the reported calculated dose distributions. Today’s modern linac is manufactured to tight specifications so that variability within a linac model is quite low. The expectation is that a single dose calculation tool for a specific linac model can be used to accurately recalculate dose from patient plans that have been submitted to the clinical trial community from any institution. The calculation tool would provide for a more meaningful outcome analysis. Methods: The analytical source model was described by a primary point source, a secondary extra-focal source, and a contaminant electron source. Off-axis energy softening and fluence effects were also included. The additions of hyperbolic functions have been incorporated into the model to correct for the changes in output and in electron contamination with field size. A multileaf collimator (MLC) model is included to facilitate phantom and patient dose calculations. An offset to the MLC leaf positions was used to correct for the rudimentary assumed primary point source. Results: Dose calculations of the depth dose and profiles for field sizes 4 × 4 to 40 × 40 cm agree with measurement within 2% of the maximum dose or 2 mm distance to agreement (DTA) for 95% of the data

  6. Validation of numerical solvers for liquid metal flow in a complex geometry in the presence of a strong magnetic field

    Science.gov (United States)

    Patel, Anita; Pulugundla, Gautam; Smolentsev, Sergey; Abdou, Mohamed; Bhattacharyay, Rajendraprasad

    2018-04-01

    Following the magnetohydrodynamic (MHD) code validation and verification proposal by Smolentsev et al. (Fusion Eng Des 100:65-72, 2015), we perform code to code and code to experiment comparisons between two computational solvers, FLUIDYN and HIMAG, which are presently considered as two of the prospective CFD tools for fusion blanket applications. In such applications, an electrically conducting breeder/coolant circulates in the blanket ducts in the presence of a strong plasma-confining magnetic field at high Hartmann numbers, it{Ha} (it{Ha}^2 is the ratio between electromagnetic and viscous forces) and high interaction parameters, it{N} (it{N} is the ratio of electromagnetic to inertial forces). The main objective of this paper is to provide the scientific and engineering community with common references to assist fusion researchers in the selection of adequate computational means to be used for blanket design and analysis. As an initial validation case, the two codes are applied to the classic problem of a laminar fully developed MHD flows in a rectangular duct. Both codes demonstrate a very good agreement with the analytical solution for it{Ha} up to 15, 000. To address the capabilities of the two codes to properly resolve complex geometry flows, we consider a case of three-dimensional developing MHD flow in a geometry comprising of a series of interconnected electrically conducting rectangular ducts. The computed electric potential distributions for two flows (Case A) it{Ha}=515, it{N}=3.2 and (Case B) it{Ha}=2059, it{N}=63.8 are in very good agreement with the experimental data, while the comparisons for the MHD pressure drop are still unsatisfactory. To better interpret the observed differences, the obtained numerical data are analyzed against earlier theoretical and experimental studies for flows that involve changes in the relative orientation between the flow and the magnetic field.

  7. External validation of the endometriosis fertility index (EFI) staging system for predicting non-ART pregnancy after endometriosis surgery.

    Science.gov (United States)

    Tomassetti, C; Geysenbergh, B; Meuleman, C; Timmerman, D; Fieuws, S; D'Hooghe, T

    2013-05-01

    Can the ability of the endometriosis fertility index (EFI) to predict non-assisted reproductive technology (ART) pregnancy after endometriosis surgery be confirmed by an external validation study? The significant relationship between the EFI score and the time to non-ART pregnancy observed in our study represents an external validation of this scoring system. The EFI was previously developed and tested prospectively in a single center, but up to now no external validation has been published. Our data provide validation of the EFI in an external fertility unit on a robust scientific basis, to identify couples with a good prognosis for spontaneous conception who can therefore defer ART treatment, regardless of their revised American Fertility Society (rAFS) endometriosis staging. Retrospective cohort study where the EFI was calculated based on history and detailed surgical findings, and related to pregnancy outcome in 233 women attempting non-ART conception immediately after surgery; all data used for EFI calculation and analysis of reproductive outcome had been collected prospectively as part of another study. The EFI score was calculated (score 0-10) for 233 women with all rAFS endometriosis stages (minimal-mild, n = 75; moderate-severe, n = 158) after endometriosis surgery (1 September 2006-30 September 2010) in a university hospital-based reproductive medicine unit with combined expertise in reproductive surgery and medically assisted reproduction. All participants attempted non-ART conception immediately after surgery by natural intercourse, ovulation induction with timed intercourse or intrauterine insemination (with or without ovulation induction or controlled ovarian stimulation). All analyses were performed for three different definitions of pregnancy [overall (any HCG >25 IU/l), clinical and ongoing >20 weeks]. Six groups were distinguished (EFI scores 1-3, 4, 5, 6, 7+8, 9+10), and Kaplan-Meier (K-M) estimates for cumulative pregnancy rate were calculated

  8. Validation of the Jarzynski relation for a system with strong thermal coupling: an isothermal ideal gas model.

    Science.gov (United States)

    Baule, A; Evans, R M L; Olmsted, P D

    2006-12-01

    We revisit the paradigm of an ideal gas under isothermal conditions. A moving piston performs work on an ideal gas in a container that is strongly coupled to a heat reservoir. The thermal coupling is modeled by stochastic scattering at the boundaries. In contrast to recent studies of an adiabatic ideal gas with a piston [R.C. Lua and A.Y. Grosberg, J. Phys. Chem. B 109, 6805 (2005); I. Bena, Europhys. Lett. 71, 879 (2005)], the container and piston stay in contact with the heat bath during the work process. Under this condition the heat reservoir as well as the system depend on the work parameter lambda and microscopic reversibility is broken for a moving piston. Our model is thus not included in the class of systems for which the nonequilibrium work theorem has been derived rigorously either by Hamiltonian [C. Jarzynski, J. Stat. Mech. (2004) P09005] or stochastic methods [G.E. Crooks, J. Stat. Phys. 90, 1481 (1998)]. Nevertheless the validity of the nonequilibrium work theorem is confirmed both numerically for a wide range of parameter values and analytically in the limit of a very fast moving piston, i.e., in the far nonequilibrium regime.

  9. External validation and calibration of IVFpredict: a national prospective cohort study of 130,960 in vitro fertilisation cycles.

    Directory of Open Access Journals (Sweden)

    Andrew D A C Smith

    Full Text Available Accurately predicting the probability of a live birth after in vitro fertilisation (IVF is important for patients, healthcare providers and policy makers. Two prediction models (Templeton and IVFpredict have been previously developed from UK data and are widely used internationally. The more recent of these, IVFpredict, was shown to have greater predictive power in the development dataset. The aim of this study was external validation of the two models and comparison of their predictive ability.130,960 IVF cycles undertaken in the UK in 2008-2010 were used to validate and compare the Templeton and IVFpredict models. Discriminatory power was calculated using the area under the receiver-operator curve and calibration assessed using a calibration plot and Hosmer-Lemeshow statistic. The scaled modified Brier score, with measures of reliability and resolution, were calculated to assess overall accuracy. Both models were compared after updating for current live birth rates to ensure that the average observed and predicted live birth rates were equal. The discriminative power of both methods was comparable: the area under the receiver-operator curve was 0.628 (95% confidence interval (CI: 0.625-0.631 for IVFpredict and 0.616 (95% CI: 0.613-0.620 for the Templeton model. IVFpredict had markedly better calibration and higher diagnostic accuracy, with calibration plot intercept of 0.040 (95% CI: 0.017-0.063 and slope of 0.932 (95% CI: 0.839-1.025 compared with 0.080 (95% CI: 0.044-0.117 and 1.419 (95% CI: 1.149-1.690 for the Templeton model. Both models underestimated the live birth rate, but this was particularly marked in the Templeton model. Updating the models to reflect improvements in live birth rates since the models were developed enhanced their performance, but IVFpredict remained superior.External validation in a large population cohort confirms IVFpredict has superior discrimination and calibration for informing patients, clinicians and

  10. Physical activity promotion in Latin American populations: a systematic review on issues of internal and external validity.

    Science.gov (United States)

    Galaviz, Karla I; Harden, Samantha M; Smith, Erin; Blackman, Kacie Ca; Berrey, Leanna M; Mama, Scherezade K; Almeida, Fabio A; Lee, Rebecca E; Estabrooks, Paul A

    2014-06-17

    The purpose of this review was to determine the degree to which physical activity interventions for Latin American populations reported on internal and external validity factors using the RE-AIM framework (reach & representativeness, effectiveness, adoption, implementation, maintenance). We systematically identified English (PubMed; EbscoHost) and Spanish (SCIELO; Biblioteca Virtual en Salud) language studies published between 2001 and 2012 that tested physical activity, exercise, or fitness promotion interventions in Latin American populations. Cross-sectional/descriptive studies, conducted in Brazil or Spain, published in Portuguese, not including a physical activity/fitness/exercise outcome, and with one time point assessment were excluded. We reviewed 192 abstracts and identified 46 studies that met the eligibility criteria (34 in English, 12 in Spanish). A validated 21-item RE-AIM abstraction tool was used to determine the quality of reporting across studies (0-7 = low, 8-14 = moderate, and 15-21 = high). The number of indicators reported ranged from 3-14 (mean = 8.1 ± 2.6), with the majority of studies falling in the moderate quality reporting category. English and Spanish language articles did not differ on the number of indicators reported (8.1 vs. 8.3, respectively). However, Spanish articles reported more across reach indicators (62% vs. 43% of indicators), while English articles reported more across effectiveness indicators (69% vs 62%). Across RE-AIM dimensions, indicators for reach (48%), efficacy/effectiveness (67%), and implementation (41%) were reported more often than indicators of adoption (25%) and maintenance (10%). Few studies reported on the representativeness of participants, staff that delivered interventions, or the settings where interventions were adopted. Only 13% of the studies reported on quality of life and/or potential negative outcomes, 20% reported on intervention fidelity, and 11% on cost of implementation

  11. External validation of the Intensive Care National Audit & Research Centre (ICNARC) risk prediction model in critical care units in Scotland.

    Science.gov (United States)

    Harrison, David A; Lone, Nazir I; Haddow, Catriona; MacGillivray, Moranne; Khan, Angela; Cook, Brian; Rowan, Kathryn M

    2014-01-01

    Risk prediction models are used in critical care for risk stratification, summarising and communicating risk, supporting clinical decision-making and benchmarking performance. However, they require validation before they can be used with confidence, ideally using independently collected data from a different source to that used to develop the model. The aim of this study was to validate the Intensive Care National Audit & Research Centre (ICNARC) model using independently collected data from critical care units in Scotland. Data were extracted from the Scottish Intensive Care Society Audit Group (SICSAG) database for the years 2007 to 2009. Recoding and mapping of variables was performed, as required, to apply the ICNARC model (2009 recalibration) to the SICSAG data using standard computer algorithms. The performance of the ICNARC model was assessed for discrimination, calibration and overall fit and compared with that of the Acute Physiology And Chronic Health Evaluation (APACHE) II model. There were 29,626 admissions to 24 adult, general critical care units in Scotland between 1 January 2007 and 31 December 2009. After exclusions, 23,269 admissions were included in the analysis. The ICNARC model outperformed APACHE II on measures of discrimination (c index 0.848 versus 0.806), calibration (Hosmer-Lemeshow chi-squared statistic 18.8 versus 214) and overall fit (Brier's score 0.140 versus 0.157; Shapiro's R 0.652 versus 0.621). Model performance was consistent across the three years studied. The ICNARC model performed well when validated in an external population to that in which it was developed, using independently collected data.

  12. Update of the German Diabetes Risk Score and external validation in the German MONICA/KORA study.

    Science.gov (United States)

    Mühlenbruch, Kristin; Ludwig, Tonia; Jeppesen, Charlotte; Joost, Hans-Georg; Rathmann, Wolfgang; Meisinger, Christine; Peters, Annette; Boeing, Heiner; Thorand, Barbara; Schulze, Matthias B

    2014-06-01

    Several published diabetes prediction models include information about family history of diabetes. The aim of this study was to extend the previously developed German Diabetes Risk Score (GDRS) with family history of diabetes and to validate the updated GDRS in the Multinational MONItoring of trends and determinants in CArdiovascular Diseases (MONICA)/German Cooperative Health Research in the Region of Augsburg (KORA) study. We used data from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study for extending the GDRS, including 21,846 participants. Within 5 years of follow-up 492 participants developed diabetes. The definition of family history included information about the father, the mother and/or sibling/s. Model extension was evaluated by discrimination and reclassification. We updated the calculation of the score and absolute risks. External validation was performed in the MONICA/KORA study comprising 11,940 participants with 315 incident cases after 5 years of follow-up. The basic ROC-AUC of 0.856 (95%-CI: 0.842-0.870) was improved by 0.007 (0.003-0.011) when parent and sibling history was included in the GDRS. The net reclassification improvement was 0.110 (0.072-0.149), respectively. For the updated score we demonstrated good calibration across all tenths of risk. In MONICA/KORA, the ROC-AUC was 0.837 (0.819-0.855); regarding calibration we saw slight overestimation of absolute risks. Inclusion of the number of diabetes-affected parents and sibling history improved the prediction of type 2 diabetes. Therefore, we updated the GDRS algorithm accordingly. Validation in another German cohort study showed good discrimination and acceptable calibration for the vast majority of individuals. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. Right Heart End-Systolic Remodeling Index Strongly Predicts Outcomes in Pulmonary Arterial Hypertension: Comparison With Validated Models.

    Science.gov (United States)

    Amsallem, Myriam; Sweatt, Andrew J; Aymami, Marie C; Kuznetsova, Tatiana; Selej, Mona; Lu, HongQuan; Mercier, Olaf; Fadel, Elie; Schnittger, Ingela; McConnell, Michael V; Rabinovitch, Marlene; Zamanian, Roham T; Haddad, Francois

    2017-06-01

    Right ventricular (RV) end-systolic dimensions provide information on both size and function. We investigated whether an internally scaled index of end-systolic dimension is incremental to well-validated prognostic scores in pulmonary arterial hypertension. From 2005 to 2014, 228 patients with pulmonary arterial hypertension were prospectively enrolled. RV end-systolic remodeling index (RVESRI) was defined by lateral length divided by septal height. The incremental values of RV free wall longitudinal strain and RVESRI to risk scores were determined. Mean age was 49±14 years, 78% were female, 33% had connective tissue disease, 52% were in New York Heart Association class ≥III, and mean pulmonary vascular resistance was 11.2±6.4 WU. RVESRI and right atrial area were strongly connected to the other right heart metrics. Three zones of adaptation (adapted, maladapted, and severely maladapted) were identified based on the RVESRI to RV systolic pressure relationship. During a mean follow-up of 3.9±2.4 years, the primary end point of death, transplant, or admission for heart failure was reached in 88 patients. RVESRI was incremental to risk prediction scores in pulmonary arterial hypertension, including the Registry to Evaluate Early and Long-Term PAH Disease Management score, the Pulmonary Hypertension Connection equation, and the Mayo Clinic model. Using multivariable analysis, New York Heart Association class III/IV, RVESRI, and log NT-proBNP (N-Terminal Pro-B-Type Natriuretic Peptide) were retained (χ 2 , 62.2; P right heart metrics, RVESRI demonstrated the best test-retest characteristics. RVESRI is a simple reproducible prognostic marker in patients with pulmonary arterial hypertension. © 2017 American Heart Association, Inc.

  14. Predictors of outcome after elective endovascular abdominal aortic aneurysm repair and external validation of a risk prediction model.

    Science.gov (United States)

    Wisniowski, Brendan; Barnes, Mary; Jenkins, Jason; Boyne, Nicholas; Kruger, Allan; Walker, Philip J

    2011-09-01

    Endovascular abdominal aortic aneurysm (AAA) repair (EVAR) has been associated with lower operative mortality and morbidity than open surgery but comparable long-term mortality and higher delayed complication and reintervention rates. Attention has therefore been directed to identifying preoperative and operative variables that influence outcomes after EVAR. Risk-prediction models, such as the EVAR Risk Assessment (ERA) model, have also been developed to help surgeons plan EVAR procedures. The aims of this study were (1) to describe outcomes of elective EVAR at the Royal Brisbane and Women's Hospital (RBWH), (2) to identify preoperative and operative variables predictive of outcomes after EVAR, and (3) to externally validate the ERA model. All elective EVAR procedures at the RBWH before July 1, 2009, were reviewed. Descriptive analyses were performed to determine the outcomes. Univariate and multivariate analyses were performed to identify preoperative and operative variables predictive of outcomes after EVAR. Binomial logistic regression analyses were used to externally validate the ERA model. Before July 1, 2009, 197 patients (172 men), who were a mean age of 72.8 years, underwent elective EVAR at the RBWH. Operative mortality was 1.0%. Survival was 81.1% at 3 years and 63.2% at 5 years. Multivariate analysis showed predictors of survival were age (P = .0126), American Society of Anesthesiologists (ASA) score (P = .0180), and chronic obstructive pulmonary disease (P = .0348) at 3 years and age (P = .0103), ASA score (P = .0006), renal failure (P = .0048), and serum creatinine (P = .0022) at 5 years. Aortic branch vessel score was predictive of initial (30-day) type II endoleak (P = .0015). AAA tortuosity was predictive of midterm type I endoleak (P = .0251). Female sex was associated with lower rates of initial clinical success (P = .0406). The ERA model fitted RBWH data well for early death (C statistic = .906), 3-year survival (C statistic = .735), 5-year

  15. Modeling and simulation of maintenance treatment in first-line non-small cell lung cancer with external validation

    International Nuclear Information System (INIS)

    Han, Kelong; Claret, Laurent; Sandler, Alan; Das, Asha; Jin, Jin; Bruno, Rene

    2016-01-01

    Maintenance treatment (MTx) in responders following first-line treatment has been investigated and practiced for many cancers. Modeling and simulation may support interpretation of interim data and development decisions. We aimed to develop a modeling framework to simulate overall survival (OS) for MTx in NSCLC using tumor growth inhibition (TGI) data. TGI metrics were estimated using longitudinal tumor size data from two Phase III first-line NSCLC studies evaluating bevacizumab and erlotinib as MTx in 1632 patients. Baseline prognostic factors and TGI metric estimates were assessed in multivariate parametric models to predict OS. The OS model was externally validated by simulating a third independent NSCLC study (n = 253) based on interim TGI data (up to progression-free survival database lock). The third study evaluated pemetrexed + bevacizumab vs. bevacizumab alone as MTx. Time-to-tumor-growth (TTG) was the best TGI metric to predict OS. TTG, baseline tumor size, ECOG score, Asian ethnicity, age, and gender were significant covariates in the final OS model. The OS model was qualified by simulating OS distributions and hazard ratios (HR) in the two studies used for model-building. Simulations of the third independent study based on interim TGI data showed that pemetrexed + bevacizumab MTx was unlikely to significantly prolong OS vs. bevacizumab alone given the current sample size (predicted HR: 0.81; 95 % prediction interval: 0.59–1.09). Predicted median OS was 17.3 months and 14.7 months in both arms, respectively. These simulations are consistent with the results of the final OS analysis published 2 years later (observed HR: 0.87; 95 % confidence interval: 0.63–1.21). Final observed median OS was 17.1 months and 13.2 months in both arms, respectively, consistent with our predictions. A robust TGI-OS model was developed for MTx in NSCLC. TTG captures treatment effect. The model successfully predicted the OS outcomes of an independent study based on interim

  16. Modeling and simulation of maintenance treatment in first-line non-small cell lung cancer with external validation.

    Science.gov (United States)

    Han, Kelong; Claret, Laurent; Sandler, Alan; Das, Asha; Jin, Jin; Bruno, Rene

    2016-07-13

    Maintenance treatment (MTx) in responders following first-line treatment has been investigated and practiced for many cancers. Modeling and simulation may support interpretation of interim data and development decisions. We aimed to develop a modeling framework to simulate overall survival (OS) for MTx in NSCLC using tumor growth inhibition (TGI) data. TGI metrics were estimated using longitudinal tumor size data from two Phase III first-line NSCLC studies evaluating bevacizumab and erlotinib as MTx in 1632 patients. Baseline prognostic factors and TGI metric estimates were assessed in multivariate parametric models to predict OS. The OS model was externally validated by simulating a third independent NSCLC study (n = 253) based on interim TGI data (up to progression-free survival database lock). The third study evaluated pemetrexed + bevacizumab vs. bevacizumab alone as MTx. Time-to-tumor-growth (TTG) was the best TGI metric to predict OS. TTG, baseline tumor size, ECOG score, Asian ethnicity, age, and gender were significant covariates in the final OS model. The OS model was qualified by simulating OS distributions and hazard ratios (HR) in the two studies used for model-building. Simulations of the third independent study based on interim TGI data showed that pemetrexed + bevacizumab MTx was unlikely to significantly prolong OS vs. bevacizumab alone given the current sample size (predicted HR: 0.81; 95 % prediction interval: 0.59-1.09). Predicted median OS was 17.3 months and 14.7 months in both arms, respectively. These simulations are consistent with the results of the final OS analysis published 2 years later (observed HR: 0.87; 95 % confidence interval: 0.63-1.21). Final observed median OS was 17.1 months and 13.2 months in both arms, respectively, consistent with our predictions. A robust TGI-OS model was developed for MTx in NSCLC. TTG captures treatment effect. The model successfully predicted the OS outcomes of an independent study

  17. Process evaluation to explore internal and external validity of the "Act in Case of Depression" care program in nursing homes.

    Science.gov (United States)

    Leontjevas, Ruslan; Gerritsen, Debby L; Koopmans, Raymond T C M; Smalbrugge, Martin; Vernooij-Dassen, Myrra J F J

    2012-06-01

    A multidisciplinary, evidence-based care program to improve the management of depression in nursing home residents was implemented and tested using a stepped-wedge design in 23 nursing homes (NHs): "Act in case of Depression" (AiD). Before effect analyses, to evaluate AiD process data on sampling quality (recruitment and randomization, reach) and intervention quality (relevance and feasibility, extent to which AiD was performed), which can be used for understanding internal and external validity. In this article, a model is presented that divides process evaluation data into first- and second-order process data. Qualitative and quantitative data based on personal files of residents, interviews of nursing home professionals, and a research database were analyzed according to the following process evaluation components: sampling quality and intervention quality. Nursing home. The pattern of residents' informed consent rates differed for dementia special care units and somatic units during the study. The nursing home staff was satisfied with the AiD program and reported that the program was feasible and relevant. With the exception of the first screening step (nursing staff members using a short observer-based depression scale), AiD components were not performed fully by NH staff as prescribed in the AiD protocol. Although NH staff found the program relevant and feasible and was satisfied with the program content, individual AiD components may have different feasibility. The results on sampling quality implied that statistical analyses of AiD effectiveness should account for the type of unit, whereas the findings on intervention quality implied that, next to the type of unit, analyses should account for the extent to which individual AiD program components were performed. In general, our first-order process data evaluation confirmed internal and external validity of the AiD trial, and this evaluation enabled further statistical fine tuning. The importance of

  18. External Validity of Randomized Controlled Trials on Alzheimer’s Disease: The Biases of Frailty and Biological Aging

    Directory of Open Access Journals (Sweden)

    Marco Canevelli

    2017-11-01

    Full Text Available To date, the external validity of randomized controlled trials (RCTs on Alzheimer’s disease (AD has been assessed only considering monodimensional variables. Nevertheless, looking at isolated and single characteristics cannot guarantee a sufficient level of appreciation of the AD patients’ complexity. The only way to understand whether the two worlds (i.e., research and clinics deal with the same type of patients is to adopt multidimensional approaches more holistically reflecting the biological age of the individual. In the present study, we compared measures of frailty/biological aging [assessed by a Frailty Index (FI] of a sample of patients with AD resulted eligible and subsequently included in phase III RCTs compared to patients referring to the same clinical service, but not considered for inclusion. The “RCT sample” and the “real world sample” were found to be statistically similar for all the considered sociodemographic and clinical variables. Nevertheless, the “real world sample” was found to be significantly frailer compared to the “RCT sample,” as indicated by higher FI scores [0.28 (SD 0.1 vs. 0.17 (SD 0.1; p < 0.001, respectively]. Moreover, when assessing the relationship between FI and age, we found that the correlation was almost null in the “RCT sample” (Spearman’s r = 0.01; p = 0.98, while it was statistically significant in the “real world sample” (r = 0.49; p = 0.02. The application of too rigid designs may result in the poor representativeness of RCT samples. It may even imply the study of a condition biologically different from that observed in the “real world.” The adoption of multidimensional measures capable to capture the individual’s biological age may facilitate evaluating the external validity of clinical studies, implicitly improving the interpretation of the results and their translation in the clinical arena.

  19. Protection of Mobile Agents Execution Using a Modified Self-Validating Branch-Based Software Watermarking with External Sentinel

    Science.gov (United States)

    Tomàs-Buliart, Joan; Fernández, Marcel; Soriano, Miguel

    Critical infrastructures are usually controlled by software entities. To monitor the well-function of these entities, a solution based in the use of mobile agents is proposed. Some proposals to detect modifications of mobile agents, as digital signature of code, exist but they are oriented to protect software against modification or to verify that an agent have been executed correctly. The aim of our proposal is to guarantee that the software is being executed correctly by a non trusted host. The way proposed to achieve this objective is by the improvement of the Self-Validating Branch-Based Software Watermarking by Myles et al.. The proposed modification is the incorporation of an external element called sentinel which controls branch targets. This technique applied in mobile agents can guarantee the correct operation of an agent or, at least, can detect suspicious behaviours of a malicious host during the execution of the agent instead of detecting when the execution of the agent have finished.

  20. External Validation of Risk Prediction Scores for Invasive Candidiasis in a Medical/Surgical Intensive Care Unit: An Observational Study

    Science.gov (United States)

    Ahmed, Armin; Baronia, Arvind Kumar; Azim, Afzal; Marak, Rungmei S. K.; Yadav, Reema; Sharma, Preeti; Gurjar, Mohan; Poddar, Banani; Singh, Ratender Kumar

    2017-01-01

    Background: The aim of this study was to conduct external validation of risk prediction scores for invasive candidiasis. Methods: We conducted a prospective observational study in a 12-bedded adult medical/surgical Intensive Care Unit (ICU) to evaluate Candida score >3, colonization index (CI) >0.5, corrected CI >0.4 (CCI), and Ostrosky's clinical prediction rule (CPR). Patients' characteristics and risk factors for invasive candidiasis were noted. Patients were divided into two groups; invasive candidiasis and no-invasive candidiasis. Results: Of 198 patients, 17 developed invasive candidiasis. Discriminatory power (area under receiver operator curve [AUROC]) for Candida score, CI, CCI, and CPR were 0.66, 0.67, 0.63, and 0.62, respectively. A large number of patients in the no-invasive candidiasis group (114 out of 181) were exposed to antifungal agents during their stay in ICU. Subgroup analysis was carried out after excluding such patients from no-invasive candidiasis group. AUROC of Candida score, CI, CCI, and CPR were 0.7, 0.7, 0.65, and 0.72, respectively, and positive predictive values (PPVs) were in the range of 25%–47%, along with negative predictive values (NPVs) in the range of 84%–96% in the subgroup analysis. Conclusion: Currently available risk prediction scores have good NPV but poor PPV. They are useful for selecting patients who are not likely to benefit from antifungal therapy. PMID:28904481

  1. External Validation of the ISAN, A2DS2, and AIS-APS Scores for Predicting Stroke-Associated Pneumonia.

    Science.gov (United States)

    Zapata-Arriaza, Elena; Moniche, Francisco; Blanca, Pardo-Galiana; Bustamante, Alejandro; Escudero-Martínez, Irene; Uclés, Oscar; Ollero-Ortiz, Ángela; Sánchez-García, Jose Antonio; Gamero, Miguel Ángel; Quesada, Ángeles; Vidal De Francisco, Diana; Romera, Mercedes; De la Cruz, Carlos; Sanz, Gema; Montaner, Joan

    2018-03-01

    The Prestroke Independence, Sex, Age, National Institutes of Health Stroke Scale (ISAN), Age, Atrial Fibrillation, Dysphagia, male sex, and National Institutes of Health Stroke Scale (A2DS2), and acute ischemic stroke-associated pneumonia score (AIS-APS) scores were created to predict stroke-associated pneumonia (SAP), one of the most important medical stroke complications. External validation of all such scores in an acute stroke population was the aim of our study. Patients with ischemic or hemorrhagic stroke were prospectively enrolled in the multicenter Stroke-Induced Pneumonia in Andalucía project between October 2014 and May 2016. Receiver operating characteristic curves and linear regression analyses were used to determine discrimination ability of the scores. The Hosmer-Lemeshow goodness-of-fit test and the plot of observed versus predicted SAP risk were used to assess model calibration. Among 201 included patients, SAP rate was 15.5% (31). Higher ISAN, A2DS2, and AIS-APS scores were related to SAP (all P manage SAP. The AIS-APS score would be recommendable for the development of future clinical trials. Copyright © 2018 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  2. Analysis of risk factors for schizophrenia with two different case definitions: a nationwide register-based external validation study.

    Science.gov (United States)

    Sørensen, Holger J; Larsen, Janne T; Mors, Ole; Nordentoft, Merete; Mortensen, Preben B; Petersen, Liselotte

    2015-03-01

    Different case definitions of schizophrenia have been used in register based research. However, no previous study has externally validated two different case definitions of schizophrenia against a wide range of risk factors for schizophrenia. We investigated hazard ratios (HRs) for a wide range of risk factors for ICD-10 DCR schizophrenia using a nationwide Danish sample of 2,772,144 residents born in 1955-1997. We compared one contact only (OCO) (the case definition of schizophrenia used in Danish register based studies) with two or more contacts (TMC) (a case definition of at least 2 inpatient contacts with schizophrenia). During the follow-up, the OCO definition included 15,074 and the TMC 7562 cases; i.e. half as many. The TMC case definition appeared to select for a worse illness course. A wide range of risk factors were uniformly associated with both case definitions and only slightly higher risk estimates were found for the TMC definition. Choosing at least 2 inpatient contacts with schizophrenia (TMC) instead of the currently used case definition would result in almost similar risk estimates for many well-established risk factors. However, this would also introduce selection and include considerably fewer cases and reduce power of e.g. genetic studies based on register-diagnosed cases only. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Validation of an amino-acid-based radionuclide therapy plus external beam radiotherapy in heterotopic glioblastoma models

    Energy Technology Data Exchange (ETDEWEB)

    Israel, Ina [Department of Nuclear Medicine, University of Wuerzburg, D-97080 Wuerzburg (Germany); Blass, Georg [Department of Radiotherapy and Radiooncology, Saarland University Medical Center, Homburg (Germany); Reiners, Christoph [Department of Nuclear Medicine, University of Wuerzburg, D-97080 Wuerzburg (Germany); Samnick, Samuel, E-mail: samnick_s@klinik.uni-wuerzburg.d [Department of Nuclear Medicine, University of Wuerzburg, D-97080 Wuerzburg (Germany)

    2011-05-15

    Background and purpose: Malignant gliomas represent a major therapeutic challenge because no efficient treatment is currently available. p-[{sup 131}I]iodo-L-phenylalanine ([{sup 131}I]IPA) is a glioma avid radiopharmaceutical that demonstrated antiproliferative and tumoricidal effects in gliomas. The present study validated the therapeutic efficiency of [{sup 131}I]IPA combined with external beam radiotherapy in experimental gliomas. Materials and methods: Glioma cells derived from the primary human A1207, T5135, Tx3868 and M059K glioblastoma cell lines or rat F98 glioma cell line were treated with various doses of [{sup 131}I]IPA, external photon irradiation (RT) or combined [{sup 131}I]IPA/RT treatment. Responsiveness of glioma cells to the different therapy modalities was investigated at 24, 48 and 72 h after treatments by trypan blue, WST-1 assay, propidium iodide and bisbenzimide staining as well as by clonogenic assay. In addition, the therapy-induced DNA damage and repair were evaluated using phosphorylated histone H2AX ({gamma}-H2AX). In vivo, the effectiveness of the combination treatment was validated in human Tx3868 and A1207 glioblastoma xenografts in CD1 nu/nu mice and RNU rats. Results: In vitro, the combination treatment resulted in a greater than additive increase in cytotoxic effect in glioma cell lines. Cell survival rate following a treatment with 1.0 {mu}Ci (37 kBq) of [{sup 131}I]IPA amounted to 70%{+-}15% and 60%{+-}10% after 48 and 72 h, respectively, and decreased under 20% after additional RT with 5 Gy. At higher RT doses, cell survival rate decreased below 5%. As a measure of DNA double-strand break, nuclear {gamma}-H2AX foci were determined as a function of time. Within 24 h, the number of {gamma}-H2AX foci per cell was significantly greater after combined modality compared with the individual treatments. In vivo, when combined with RT, the radionuclide therapy with [{sup 131}I]IPA resulted in an extended tumor growth delay, a reduction

  4. Triviality - quantum decoherence of Fermionic quantum chromodynamics SU (Nc) in the presence of an external strong U (∞) flavored constant noise field

    International Nuclear Information System (INIS)

    Botelho, Luiz C.L.

    2008-01-01

    We analyze the triviality-quantum decoherence of Euclidean quantum chromodynamics in the gauge invariant quark current sector in the presence of an external U (∞) flavor constant charged white noise reservoir. (author)

  5. Predicting new service adoption with conjoint analysis : External validity of BDM-based incentive-aligned and dual-response choice designs

    NARCIS (Netherlands)

    Wlömert, Nils; Eggers, Felix

    2016-01-01

    In this paper, we compare the standard, single-response choice-based con- joint (CBC) approach with three extended CBC procedures in terms of their external predictive validity and their ability to realistically capture consumers’ willingness to pay: (1) an incentive-aligned CBC mechanism (IA-CBC),

  6. Poor quality of external validity reporting limits generalizability of overweight and/or obesity lifestyle prevention interventions in young adults: a systematic review.

    Science.gov (United States)

    Partridge, S R; Juan, S J-H; McGeechan, K; Bauman, A; Allman-Farinelli, M

    2015-01-01

    Young adulthood is a high-risk life stage for weight gain. Evidence is needed to translate behavioural approaches into community practice to prevent weight gain in young adults. This systematic review assessed the effectiveness and reporting of external validity components in prevention interventions. The search was limited to randomized controlled trial (RCT) lifestyle interventions for the prevention of weight gain in young adults (18-35 years). Mean body weight and/or body mass index (BMI) change were the primary outcomes. External validity, quality assessment and risk of bias tools were applied to all studies. Twenty-one RCTs were identified through 14 major electronic databases. Over half of the studies were effective in the short term for significantly reducing body weight and/or BMI; however, few showed long-term maintenance. All studies lacked full reporting on external validity components. Description of the intervention components and participant attrition rates were reported by most studies. However, few studies reported the representativeness of participants, effectiveness of recruitment methods, process evaluation detail or costs. It is unclear from the information reported how to implement the interventions into community practice. Integrated reporting of intervention effectiveness and enhanced reporting of external validity components are needed for the translation and potential upscale of prevention strategies. © 2014 World Obesity.

  7. Predictive Accuracy of the PanCan Lung Cancer Risk Prediction Model -External Validation based on CT from the Danish Lung Cancer Screening Trial

    NARCIS (Netherlands)

    Wille, M.M.W.; Riel, S.J. van; Saghir, Z.; Dirksen, A.; Pedersen, J.H.; Jacobs, C.; Thomsen, L.H.u.; Scholten, E.T.; Skovgaard, L.T.; Ginneken, B. van

    2015-01-01

    Lung cancer risk models should be externally validated to test generalizability and clinical usefulness. The Danish Lung Cancer Screening Trial (DLCST) is a population-based prospective cohort study, used to assess the discriminative performances of the PanCan models.From the DLCST database, 1,152

  8. External validation of two prediction models identifying employees at risk of high sickness absence : cohort study with 1-year follow-up

    NARCIS (Netherlands)

    Roelen, Corne A. M.; Bultmann, Ute; van Rhenen, Willem; van der Klink, Jac J. L.; Twisk, Jos W. R.; Heymans, Martijn W.

    2013-01-01

    Background: Two models including age, self-rated health (SRH) and prior sickness absence (SA) were found to predict high SA in health care workers. The present study externally validated these prediction models in a population of office workers and investigated the effect of adding gender as a

  9. External validation and comparison of two variants of the Elixhauser comorbidity measures for all-cause mortality.

    Directory of Open Access Journals (Sweden)

    Yannick Fortin

    Full Text Available Assessing prevalent comorbidities is a common approach in health research for identifying clinical differences between individuals. The objective of this study was to validate and compare the predictive performance of two variants of the Elixhauser comorbidity measures (ECM for inhospital mortality at index and at 1-year in the Cerner Health Facts® (HF U.S.We estimated the prevalence of select comorbidities for individuals 18 to 89 years of age who received care at Cerner contributing health facilities between 2002 and 2011 using the AHRQ (version 3.7 and the Quan Enhanced ICD-9-CM ECMs. External validation of the ECMs was assessed with measures of discrimination [c-statistics], calibration [Hosmer-Lemeshow goodness-of-fit test, Brier Score, calibration curves], added predictive ability [Net Reclassification Improvement], and overall model performance [R2]. Of 3,273,298 patients with a mean age of 43.9 years and a female composition of 53.8%, 1.0% died during their index encounter and 1.5% were deceased at 1-year. Calibration measures were equivalent between the two ECMs. Calibration performance was acceptable when predicting inhospital mortality at index, although recalibration is recommended for predicting inhospital mortality at 1 year. Discrimination was marginally better with the Quan ECM compared the AHRQ ECM when predicting inhospital mortality at index (cQuan = 0.887, 95% CI: 0.885-0.889 vs. cAHRQ = 0.880, 95% CI: 0.878-0.882; p < .0001 and at 1-year (cQuan = 0.884, 95% CI: 0.883-0.886 vs. cAHRQ = 0.880, 95% CI: 0.878-0.881, p < .0001. Both the Quan and the AHRQ ECMs demonstrated excellent discrimination for inhospital mortality of all-causes in Cerner Health Facts®, a HIPAA compliant observational research and privacy-protected data warehouse. While differences in discrimination performance between the ECMs were statistically significant, they are not likely clinically meaningful.

  10. External Validation of Contact Surface Area as a Predictor of Postoperative Renal Function in Patients Undergoing Partial Nephrectomy.

    Science.gov (United States)

    Haifler, Miki; Ristau, Benjamin T; Higgins, Andrew M; Smaldone, Marc C; Kutikov, Alexander; Zisman, Amnon; Uzzo, Robert G

    2017-09-20

    We sought to externally validate a mathematical formula for tumor contact surface area as a predictor of postoperative renal function in patients undergoing partial nephrectomy for renal cell carcinoma. We queried a prospectively maintained kidney cancer database for patients who underwent partial nephrectomy between 2014 and 2016. Contact surface area was calculated using data obtained from preoperative cross-sectional imaging. The correlation between contact surface area and perioperative variables was examined. The correlation between postoperative renal functional outcomes, contact surface area and the R.E.N.A.L. (radius, exophytic/endophytic properties, nearness of tumor to collecting system or sinus, anterior/posterior, location relative to polar lines and tumor touches main renal artery or vein) nephrometry score was also assessed. A total of 257 patients who underwent partial nephrectomy had sufficient data to enter the study. Median contact surface area was 14.5 cm 2 (IQR 6.2-36) and the median nephrometry score was 9 (IQR 7-10). Spearman correlation analysis showed that contact surface area correlated with estimated blood loss (r s = 0.42, p contact surface area and nephrometry score were independent predictors of the absolute change in the estimated glomerular filtration rate (each p contact surface area was a better predictor of a greater than 20% postoperative decline in the estimated glomerular filtration rate compared with the nephrometry score (AUC 0.94 vs 0.80). Contact surface area correlated with the change in postoperative renal function after partial nephrectomy. It can be used in conjunction with the nephrometry score to counsel patients about the risk of renal functional decline after partial nephrectomy. Copyright © 2018 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  11. Fast ignition realization experiment with high-contrast kilo-joule peta-watt LFEX laser and strong external magnetic field

    Science.gov (United States)

    Fujioka, Shinsuke; Arikawa, Yasunobu; Kojima, Sadaoki; Johzaki, Tomoyuki; Nagatomo, Hideo; Sawada, Hiroshi; Lee, Seung Ho; Shiroto, Takashi; Ohnishi, Naofumi; Morace, Alessio; Vaisseau, Xavier; Sakata, Shohei; Abe, Yuki; Matsuo, Kazuki; Farley Law, King Fai; Tosaki, Shota; Yogo, Akifumi; Shigemori, Keisuke; Hironaka, Yoichiro; Zhang, Zhe; Sunahara, Atsushi; Ozaki, Tetsuo; Sakagami, Hitoshi; Mima, Kunioki; Fujimoto, Yasushi; Yamanoi, Kohei; Norimatsu, Takayoshi; Tokita, Shigeki; Nakata, Yoshiki; Kawanaka, Junji; Jitsuno, Takahisa; Miyanaga, Noriaki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Kondo, Kotaro; Bailly-Grandvaux, Mathieu; Bellei, Claudio; Santos, João Jorge; Azechi, Hiroshi

    2016-05-01

    plasma. Following the above improvements, conversion of 13% of the LFEX laser energy to a low energy portion of the REB, whose slope temperature is 0.7 MeV, which is close to the ponderomotive scaling value, was achieved. To meet the second requirement, the compression of a solid spherical ball with a diameter of 200-μm to form a dense core with an areal density of ˜0.07 g/cm2 was induced by a laser-driven spherically converging shock wave. Converging shock compression is more hydrodynamically stable compared to shell implosion, while a hot spot cannot be generated with a solid ball target. Solid ball compression is preferable also for compressing an external magnetic field to collimate the REB to the fuel core, due to the relatively small magnetic Reynolds number of the shock compressed region. To meet the third requirement, we have generated a strong kilo-tesla magnetic field using a laser-driven capacitor-coil target. The strength and time history of the magnetic field were characterized with proton deflectometry and a B-dot probe. Guidance of the REB using a 0.6-kT field in a planar geometry has been demonstrated at the LULI 2000 laser facility. In a realistic FI scenario, a magnetic mirror is formed between the REB generation point and the fuel core. The effects of the strong magnetic field on not only REB transport but also plasma compression were studied using numerical simulations. According to the transport calculations, the heating efficiency can be improved from 0.4% to 4% by the GEKKO and LFEX laser system by meeting the three requirements described above. This efficiency is scalable to 10% of the heating efficiency by increasing the areal density of the fuel core.

  12. Fast ignition realization experiment with high-contrast kilo-joule peta-watt LFEX laser and strong external magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Fujioka, Shinsuke, E-mail: sfujioka@ile.osaka-u.ac.jp; Arikawa, Yasunobu; Kojima, Sadaoki; Nagatomo, Hideo; Lee, Seung Ho; Morace, Alessio; Vaisseau, Xavier; Sakata, Shohei; Abe, Yuki; Matsuo, Kazuki; Farley Law, King Fai; Tosaki, Shota; Yogo, Akifumi; Shigemori, Keisuke; Hironaka, Yoichiro; Fujimoto, Yasushi; Yamanoi, Kohei; Norimatsu, Takayoshi; Tokita, Shigeki; Nakata, Yoshiki [Institute of Laser Engineering, Osaka University, 2-6 Yamada-Oka, Suita, Osaka 565-0871 Japan (Japan); and others

    2016-05-15

    by imploding plasma. Following the above improvements, conversion of 13% of the LFEX laser energy to a low energy portion of the REB, whose slope temperature is 0.7 MeV, which is close to the ponderomotive scaling value, was achieved. To meet the second requirement, the compression of a solid spherical ball with a diameter of 200-μm to form a dense core with an areal density of ∼0.07 g/cm{sup 2} was induced by a laser-driven spherically converging shock wave. Converging shock compression is more hydrodynamically stable compared to shell implosion, while a hot spot cannot be generated with a solid ball target. Solid ball compression is preferable also for compressing an external magnetic field to collimate the REB to the fuel core, due to the relatively small magnetic Reynolds number of the shock compressed region. To meet the third requirement, we have generated a strong kilo-tesla magnetic field using a laser-driven capacitor-coil target. The strength and time history of the magnetic field were characterized with proton deflectometry and a B-dot probe. Guidance of the REB using a 0.6-kT field in a planar geometry has been demonstrated at the LULI 2000 laser facility. In a realistic FI scenario, a magnetic mirror is formed between the REB generation point and the fuel core. The effects of the strong magnetic field on not only REB transport but also plasma compression were studied using numerical simulations. According to the transport calculations, the heating efficiency can be improved from 0.4% to 4% by the GEKKO and LFEX laser system by meeting the three requirements described above. This efficiency is scalable to 10% of the heating efficiency by increasing the areal density of the fuel core.

  13. External validation of a publicly available computer assisted diagnostic tool for mammographic mass lesions with two high prevalence research datasets.

    Science.gov (United States)

    Benndorf, Matthias; Burnside, Elizabeth S; Herda, Christoph; Langer, Mathias; Kotter, Elmar

    2015-08-01

    Lesions detected at mammography are described with a highly standardized terminology: the breast imaging-reporting and data system (BI-RADS) lexicon. Up to now, no validated semantic computer assisted classification algorithm exists to interactively link combinations of morphological descriptors from the lexicon to a probabilistic risk estimate of malignancy. The authors therefore aim at the external validation of the mammographic mass diagnosis (MMassDx) algorithm. A classification algorithm like MMassDx must perform well in a variety of clinical circumstances and in datasets that were not used to generate the algorithm in order to ultimately become accepted in clinical routine. The MMassDx algorithm uses a naïve Bayes network and calculates post-test probabilities of malignancy based on two distinct sets of variables, (a) BI-RADS descriptors and age ("descriptor model") and (b) BI-RADS descriptors, age, and BI-RADS assessment categories ("inclusive model"). The authors evaluate both the MMassDx (descriptor) and MMassDx (inclusive) models using two large publicly available datasets of mammographic mass lesions: the digital database for screening mammography (DDSM) dataset, which contains two subsets from the same examinations-a medio-lateral oblique (MLO) view and cranio-caudal (CC) view dataset-and the mammographic mass (MM) dataset. The DDSM contains 1220 mass lesions and the MM dataset contains 961 mass lesions. The authors evaluate discriminative performance using area under the receiver-operating-characteristic curve (AUC) and compare this to the BI-RADS assessment categories alone (i.e., the clinical performance) using the DeLong method. The authors also evaluate whether assigned probabilistic risk estimates reflect the lesions' true risk of malignancy using calibration curves. The authors demonstrate that the MMassDx algorithms show good discriminatory performance. AUC for the MMassDx (descriptor) model in the DDSM data is 0.876/0.895 (MLO/CC view) and AUC

  14. External validation of the DRAGON score in an elderly Spanish population: prediction of stroke prognosis after IV thrombolysis.

    Science.gov (United States)

    Giralt-Steinhauer, Eva; Rodríguez-Campello, Ana; Cuadrado-Godia, Elisa; Ois, Ángel; Jiménez-Conde, Jordi; Soriano-Tárraga, Carolina; Roquer, Jaume

    2013-01-01

    Intravenous (i.v.) thrombolysis within 4.5 h of symptom onset has proven efficacy in acute ischemic stroke treatment, although half of all outcomes are unfavorable. The recently published DRAGON score aims to predict the 3-month outcome in stroke patients who have received i.v. alteplase. The purpose of this study was an external validation of the results of the DRAGON score in a Spanish cohort. Patients with acute stroke treated with alteplase were prospectively registered in our BasicMar database. We collected demographic characteristics, vascular risk factors, the time from stroke onset to treatment, baseline serum glucose levels and stroke severity for this population. We then reviewed hyperdense cerebral artery signs and signs of early infarct on the admission CT scan. We calculated the DRAGON score and used the developers' 3-month prognosis categories: good [modified Rankin Scale score (mRS) 0-2], poor (mRS 3-6) and miserable (mRS 5-6) outcome. Discrimination was tested using the area under the receiver operator curve (AUC-ROC). Calibration was assessed by the Hosmer-Lemeshow test. Our final cohort of 297 patients was older (median age 74 years, IQR 65-80) and had more risk factors and severe strokes [median National Institutes of Health Stroke Scale (NIHSS) points 13, IQR 7-19] than the original study population. Poor prognosis was observed in 143 (48.1%) patients. Higher DRAGON scores were associated with a higher risk of poor prognosis. None of our treated stroke patients with a DRAGON score ≥8 at admission experienced a favorable outcome after 3 months. All DRAGON variables were significantly associated with a worse outcome in the multivariate analysis except for onset-to-treatment time (p = 0.334). Discrimination to predict poor prognosis was very good (AUC-ROC 0.84) and the score had good Hosmer-Lemeshow calibration (p = 0.84). The DRAGON score is easy to perform and offers a rapid, reliable prediction of poor prognosis in acute-stroke patients

  15. Multisite external validation of a risk prediction model for the diagnosis of blood stream infections in febrile pediatric oncology patients without severe neutropenia.

    Science.gov (United States)

    Esbenshade, Adam J; Zhao, Zhiguo; Aftandilian, Catherine; Saab, Raya; Wattier, Rachel L; Beauchemin, Melissa; Miller, Tamara P; Wilkes, Jennifer J; Kelly, Michael J; Fernbach, Alison; Jeng, Michael; Schwartz, Cindy L; Dvorak, Christopher C; Shyr, Yu; Moons, Karl G M; Sulis, Maria-Luisa; Friedman, Debra L

    2017-10-01

    Pediatric oncology patients are at an increased risk of invasive bacterial infection due to immunosuppression. The risk of such infection in the absence of severe neutropenia (absolute neutrophil count ≥ 500/μL) is not well established and a validated prediction model for blood stream infection (BSI) risk offers clinical usefulness. A 6-site retrospective external validation was conducted using a previously published risk prediction model for BSI in febrile pediatric oncology patients without severe neutropenia: the Esbenshade/Vanderbilt (EsVan) model. A reduced model (EsVan2) excluding 2 less clinically reliable variables also was created using the initial EsVan model derivative cohort, and was validated using all 5 external validation cohorts. One data set was used only in sensitivity analyses due to missing some variables. From the 5 primary data sets, there were a total of 1197 febrile episodes and 76 episodes of bacteremia. The overall C statistic for predicting bacteremia was 0.695, with a calibration slope of 0.50 for the original model and a calibration slope of 1.0 when recalibration was applied to the model. The model performed better in predicting high-risk bacteremia (gram-negative or Staphylococcus aureus infection) versus BSI alone, with a C statistic of 0.801 and a calibration slope of 0.65. The EsVan2 model outperformed the EsVan model across data sets with a C statistic of 0.733 for predicting BSI and a C statistic of 0.841 for high-risk BSI. The results of this external validation demonstrated that the EsVan and EsVan2 models are able to predict BSI across multiple performance sites and, once validated and implemented prospectively, could assist in decision making in clinical practice. Cancer 2017;123:3781-3790. © 2017 American Cancer Society. © 2017 American Cancer Society.

  16. Real external predictivity of QSAR models: how to evaluate it? Comparison of different validation criteria and proposal of using the concordance correlation coefficient.

    Science.gov (United States)

    Chirico, Nicola; Gramatica, Paola

    2011-09-26

    The main utility of QSAR models is their ability to predict activities/properties for new chemicals, and this external prediction ability is evaluated by means of various validation criteria. As a measure for such evaluation the OECD guidelines have proposed the predictive squared correlation coefficient Q(2)(F1) (Shi et al.). However, other validation criteria have been proposed by other authors: the Golbraikh-Tropsha method, r(2)(m) (Roy), Q(2)(F2) (Schüürmann et al.), Q(2)(F3) (Consonni et al.). In QSAR studies these measures are usually in accordance, though this is not always the case, thus doubts can arise when contradictory results are obtained. It is likely that none of the aforementioned criteria is the best in every situation, so a comparative study using simulated data sets is proposed here, using threshold values suggested by the proponents or those widely used in QSAR modeling. In addition, a different and simple external validation measure, the concordance correlation coefficient (CCC), is proposed and compared with other criteria. Huge data sets were used to study the general behavior of validation measures, and the concordance correlation coefficient was shown to be the most restrictive. On using simulated data sets of a more realistic size, it was found that CCC was broadly in agreement, about 96% of the time, with other validation measures in accepting models as predictive, and in almost all the examples it was the most precautionary. The proposed concordance correlation coefficient also works well on real data sets, where it seems to be more stable, and helps in making decisions when the validation measures are in conflict. Since it is conceptually simple, and given its stability and restrictiveness, we propose the concordance correlation coefficient as a complementary, or alternative, more prudent measure of a QSAR model to be externally predictive.

  17. Development and external validation of a clinical prognostic score for death in visceral leishmaniasis patients in a high HIV co-infection burden area in Ethiopia.

    Directory of Open Access Journals (Sweden)

    Charles Abongomera

    Full Text Available In Ethiopia, case fatality rates among subgroups of visceral leishmaniasis (VL patients are high. A clinical prognostic score for death in VL patients could contribute to optimal management and reduction of these case fatality rates. We aimed to identify predictors of death from VL, and to develop and externally validate a clinical prognostic score for death in VL patients, in a high HIV co-infection burden area in Ethiopia.We conducted a retrospective cohort study in north west Ethiopia. Predictors with an adjusted likelihood ratio ≥1.5 or ≤0.67 were retained to calculate the predictor score. The derivation cohort consisted of 1686 VL patients treated at an upgraded health center and the external validation cohort consisted of 404 VL patients treated in hospital. There were 99 deaths in the derivation cohort and 53 deaths in the external validation cohort. The predictors of death were: age >40 years (score +1; HIV seropositive (score +1; HIV seronegative (score -1; hemoglobin ≤6.5 g/dl (score +1; bleeding (score +1; jaundice (score +1; edema (score +1; ascites (score +2 and tuberculosis (score +1. The total predictor score per patient ranged from -1 to +5. A score of -1, indicated a low risk of death (1.0%, a score of 0 an intermediate risk of death (3.8% and a score of +1 to +5, a high risk of death (10.4-85.7%. The area under the receiver operating characteristic curve was 0.83 (95% confidence interval: 0.79-0.87 in derivation, and 0.78 (95% confidence interval: 0.72-0.83 in external validation.The overall performance of the score was good. The score can enable the early detection of VL cases at high risk of death, which can inform operational, clinical management guidelines, and VL program management. Implementation of focused strategies could contribute to optimal management and reduction of the case fatality rates.

  18. External validation and clinical utility of a prediction model for 6-month mortality in patients undergoing hemodialysis for end-stage kidney disease.

    Science.gov (United States)

    Forzley, Brian; Er, Lee; Chiu, Helen Hl; Djurdjev, Ognjenka; Martinusen, Dan; Carson, Rachel C; Hargrove, Gaylene; Levin, Adeera; Karim, Mohamud

    2018-02-01

    End-stage kidney disease is associated with poor prognosis. Health care professionals must be prepared to address end-of-life issues and identify those at high risk for dying. A 6-month mortality prediction model for patients on dialysis derived in the United States is used but has not been externally validated. We aimed to assess the external validity and clinical utility in an independent cohort in Canada. We examined the performance of the published 6-month mortality prediction model, using discrimination, calibration, and decision curve analyses. Data were derived from a cohort of 374 prevalent dialysis patients in two regions of British Columbia, Canada, which included serum albumin, age, peripheral vascular disease, dementia, and answers to the "the surprise question" ("Would I be surprised if this patient died within the next year?"). The observed mortality in the validation cohort was 11.5% at 6 months. The prediction model had reasonable discrimination (c-stat = 0.70) but poor calibration (calibration-in-the-large = -0.53 (95% confidence interval: -0.88, -0.18); calibration slope = 0.57 (95% confidence interval: 0.31, 0.83)) in our data. Decision curve analysis showed the model only has added value in guiding clinical decision in a small range of threshold probabilities: 8%-20%. Despite reasonable discrimination, the prediction model has poor calibration in this external study cohort; thus, it may have limited clinical utility in settings outside of where it was derived. Decision curve analysis clarifies limitations in clinical utility not apparent by receiver operating characteristic curve analysis. This study highlights the importance of external validation of prediction models prior to routine use in clinical practice.

  19. STRONG POINTS AND INTERNAL AND EXTERNAL VULNERABILITIES OF THE MILITARY COMMUNICATIONS AND INFORMATICS SYSTEMS AND NETWORKS DEVELOPED IN THE ROMANIAN ARMED FORCES UNDER THE CIRCUMSTANCES OF THE CURRENT SECURITY CHALLENGES

    Directory of Open Access Journals (Sweden)

    Constantin MINCU

    2015-12-01

    Full Text Available The author briefly presents a series of recent aspects in the current geopolitical context regarding some strong points as well as internal and external vulnerabilities of the military communication and informatics systems and networks developed in the Romanian Armed Forces since 1997. In the second section we referred to the evolutions in austerity and hostility conditions of the main operational and technical sequels of Romanian Armed Forces Transmissions System - STAR (RTP/RMNC. Furthermore, we presented some strong points of the achieved systems and principles taken into account along the modernization and transformation effort (regarding the NATO criteria and requirements, as well as their internal and external vulnerabilities identified following a thorough analysis.

  20. The SCEC Broadband Platform: A Collaborative Open-Source Software Package for Strong Ground Motion Simulation and Validation

    Science.gov (United States)

    Silva, F.; Maechling, P. J.; Goulet, C. A.; Somerville, P.; Jordan, T. H.

    2014-12-01

    The Southern California Earthquake Center (SCEC) Broadband Platform is a collaborative software development project involving geoscientists, earthquake engineers, graduate students, and the SCEC Community Modeling Environment. The SCEC Broadband Platform (BBP) is open-source scientific software that can generate broadband (0-100Hz) ground motions for earthquakes, integrating complex scientific modules that implement rupture generation, low and high-frequency seismogram synthesis, non-linear site effects calculation, and visualization into a software system that supports easy on-demand computation of seismograms. The Broadband Platform operates in two primary modes: validation simulations and scenario simulations. In validation mode, the Platform runs earthquake rupture and wave propagation modeling software to calculate seismograms for a well-observed historical earthquake. Then, the BBP calculates a number of goodness of fit measurements that quantify how well the model-based broadband seismograms match the observed seismograms for a certain event. Based on these results, the Platform can be used to tune and validate different numerical modeling techniques. In scenario mode, the Broadband Platform can run simulations for hypothetical (scenario) earthquakes. In this mode, users input an earthquake description, a list of station names and locations, and a 1D velocity model for their region of interest, and the Broadband Platform software then calculates ground motions for the specified stations. Working in close collaboration with scientists and research engineers, the SCEC software development group continues to add new capabilities to the Broadband Platform and to release new versions as open-source scientific software distributions that can be compiled and run on many Linux computer systems. Our latest release includes 5 simulation methods, 7 simulation regions covering California, Japan, and Eastern North America, the ability to compare simulation results

  1. Validation of the prognostic gene portfolio, ClinicoMolecular Triad Classification, using an independent prospective breast cancer cohort and external patient populations.

    Science.gov (United States)

    Wang, Dong-Yu; Done, Susan J; Mc Cready, David R; Leong, Wey L

    2014-07-04

    Using genome-wide expression profiles of a prospective training cohort of breast cancer patients, ClinicoMolecular Triad Classification (CMTC) was recently developed to classify breast cancers into three clinically relevant groups to aid treatment decisions. CMTC was found to be both prognostic and predictive in a large external breast cancer cohort in that study. This study serves to validate the reproducibility of CMTC and its prognostic value using independent patient cohorts. An independent internal cohort (n = 284) and a new external cohort (n = 2,181) were used to validate the association of CMTC between clinicopathological factors, 12 known gene signatures, two molecular subtype classifiers, and 19 oncogenic signalling pathway activities, and to reproduce the abilities of CMTC to predict clinical outcomes of breast cancer. In addition, we also updated the outcome data of the original training cohort (n = 147). The original training cohort reached a statistically significant difference (p value of the triad classification was reproduced in the second independent internal cohort and the new external validation cohort. CMTC achieved even higher prognostic significance when all available patients were analyzed (n = 4,851). Oncogenic pathways Myc, E2F1, Ras and β-catenin were again implicated in the high-risk groups. Both prospective internal cohorts and the independent external cohorts reproduced the triad classification of CMTC and its prognostic significance. CMTC is an independent prognostic predictor, and it outperformed 12 other known prognostic gene signatures, molecular subtype classifications, and all other standard prognostic clinicopathological factors. Our results support further development of CMTC portfolio into a guide for personalized breast cancer treatments.

  2. Validation of the prognostic gene portfolio, ClinicoMolecular Triad Classification, using an independent prospective breast cancer cohort and external patient populations

    Science.gov (United States)

    2014-01-01

    Introduction Using genome-wide expression profiles of a prospective training cohort of breast cancer patients, ClinicoMolecular Triad Classification (CMTC) was recently developed to classify breast cancers into three clinically relevant groups to aid treatment decisions. CMTC was found to be both prognostic and predictive in a large external breast cancer cohort in that study. This study serves to validate the reproducibility of CMTC and its prognostic value using independent patient cohorts. Methods An independent internal cohort (n = 284) and a new external cohort (n = 2,181) were used to validate the association of CMTC between clinicopathological factors, 12 known gene signatures, two molecular subtype classifiers, and 19 oncogenic signalling pathway activities, and to reproduce the abilities of CMTC to predict clinical outcomes of breast cancer. In addition, we also updated the outcome data of the original training cohort (n = 147). Results The original training cohort reached a statistically significant difference (p risk groups. Conclusions Both prospective internal cohorts and the independent external cohorts reproduced the triad classification of CMTC and its prognostic significance. CMTC is an independent prognostic predictor, and it outperformed 12 other known prognostic gene signatures, molecular subtype classifications, and all other standard prognostic clinicopathological factors. Our results support further development of CMTC portfolio into a guide for personalized breast cancer treatments. PMID:24996446

  3. Development of risk assessment methodology against natural external hazards for sodium-cooled fast reactors: project overview and strong Wind PRA methodology - 15031

    International Nuclear Information System (INIS)

    Yamano, H.; Nishino, H.; Kurisaka, K.; Okano, Y.; Sakai, T.; Yamamoto, T.; Ishizuka, Y.; Geshi, N.; Furukawa, R.; Nanayama, F.; Takata, T.; Azuma, E.

    2015-01-01

    This paper describes mainly strong wind probabilistic risk assessment (PRA) methodology development in addition to the project overview. In this project, to date, the PRA methodologies against snow, tornado and strong wind were developed as well as the hazard evaluation methodologies. For the volcanic eruption hazard, ash fallout simulation was carried out to contribute to the development of the hazard evaluation methodology. For the forest fire hazard, the concept of the hazard evaluation methodology was developed based on fire simulation. Event sequence assessment methodology was also developed based on plant dynamics analysis coupled with continuous Markov chain Monte Carlo method in order to apply to the event sequence against snow. In developing the strong wind PRA methodology, hazard curves were estimated by using Weibull and Gumbel distributions based on weather data recorded in Japan. The obtained hazard curves were divided into five discrete categories for event tree quantification. Next, failure probabilities for decay heat removal related components were calculated as a product of two probabilities: i.e., a probability for the missiles to enter the intake or out-take in the decay heat removal system, and fragility caused by the missile impacts. Finally, based on the event tree, the core damage frequency was estimated about 6*10 -9 /year by multiplying the discrete hazard probabilities in the Gumbel distribution by the conditional decay heat removal failure probabilities. A dominant sequence was led by the assumption that the operators could not extinguish fuel tank fire caused by the missile impacts and the fire induced loss of the decay heat removal system. (authors)

  4. Development and validation of a computational model to study the effect of foot constraint on ankle injury due to external rotation.

    Science.gov (United States)

    Wei, Feng; Hunley, Stanley C; Powell, John W; Haut, Roger C

    2011-02-01

    Recent studies, using two different manners of foot constraint, potted and taped, document altered failure characteristics in the human cadaver ankle under controlled external rotation of the foot. The posterior talofibular ligament (PTaFL) was commonly injured when the foot was constrained in potting material, while the frequency of deltoid ligament injury was higher for the taped foot. In this study an existing multibody computational modeling approach was validated to include the influence of foot constraint, determine the kinematics of the joint under external foot rotation, and consequently obtain strains in various ligaments. It was hypothesized that the location of ankle injury due to excessive levels of external foot rotation is a function of foot constraint. The results from this model simulation supported this hypothesis and helped to explain the mechanisms of injury in the cadaver experiments. An excessive external foot rotation might generate a PTaFL injury for a rigid foot constraint, and an anterior deltoid ligament injury for a pliant foot constraint. The computational models may be further developed and modified to simulate the human response for different shoe designs, as well as on various athletic shoe-surface interfaces, so as to provide a computational basis for optimizing athletic performance with minimal injury risk.

  5. A computable phenotype for asthma case identification in adult and pediatric patients: External validation in the Chicago Area Patient-Outcomes Research Network (CAPriCORN).

    Science.gov (United States)

    Afshar, Majid; Press, Valerie G; Robison, Rachel G; Kho, Abel N; Bandi, Sindhura; Biswas, Ashvini; Avila, Pedro C; Kumar, Harsha Vardhan Madan; Yu, Byung; Naureckas, Edward T; Nyenhuis, Sharmilee M; Codispoti, Christopher D

    2017-10-13

    Comprehensive, rapid, and accurate identification of patients with asthma for clinical care and engagement in research efforts is needed. The original development and validation of a computable phenotype for asthma case identification occurred at a single institution in Chicago and demonstrated excellent test characteristics. However, its application in a diverse payer mix, across different health systems and multiple electronic health record vendors, and in both children and adults was not examined. The objective of this study is to externally validate the computable phenotype across diverse Chicago institutions to accurately identify pediatric and adult patients with asthma. A cohort of 900 asthma and control patients was identified from the electronic health record between January 1, 2012 and November 30, 2014. Two physicians at each site independently reviewed the patient chart to annotate cases. The inter-observer reliability between the physician reviewers had a κ-coefficient of 0.95 (95% CI 0.93-0.97). The accuracy, sensitivity, specificity, negative predictive value, and positive predictive value of the computable phenotype were all above 94% in the full cohort. The excellent positive and negative predictive values in this multi-center external validation study establish a useful tool to identify asthma cases in in the electronic health record for research and care. This computable phenotype could be used in large-scale comparative-effectiveness trials.

  6. External Validity of a Risk Stratification Score Predicting Early Distant Brain Failure and Salvage Whole Brain Radiation Therapy After Stereotactic Radiosurgery for Brain Metastases.

    Science.gov (United States)

    Press, Robert H; Boselli, Danielle M; Symanowski, James T; Lankford, Scott P; McCammon, Robert J; Moeller, Benjamin J; Heinzerling, John H; Fasola, Carolina E; Burri, Stuart H; Patel, Kirtesh R; Asher, Anthony L; Sumrall, Ashley L; Curran, Walter J; Shu, Hui-Kuo G; Crocker, Ian R; Prabhu, Roshan S

    2017-07-01

    A scoring system using pretreatment factors was recently published for predicting the risk of early (≤6 months) distant brain failure (DBF) and salvage whole brain radiation therapy (WBRT) after stereotactic radiosurgery (SRS) alone. Four risk factors were identified: (1) lack of prior WBRT; (2) melanoma or breast histologic features; (3) multiple brain metastases; and (4) total volume of brain metastases external patient population. We reviewed the records of 247 patients with 388 brain metastases treated with SRS between 2010 at 2013 at Levine Cancer Institute. The Press (Emory) risk score was calculated and applied to the validation cohort population, and subsequent risk groups were analyzed using cumulative incidence. The low-risk (LR) group had a significantly lower risk of early DBF than did the high-risk (HR) group (22.6% vs 44%, P=.004), but there was no difference between the HR and intermediate-risk (IR) groups (41.2% vs 44%, P=.79). Total lesion volume externally valid, but the model was able to stratify between 2 levels (LR and not-LR [combined IR and HR]) for early (≤6 months) DBF. These results reinforce the importance of validating predictive models in independent cohorts. Further refinement of this scoring system with molecular information and in additional contemporary patient populations is warranted. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. External validation of a PCA-3-based nomogram for predicting prostate cancer and high-grade cancer on initial prostate biopsy.

    Science.gov (United States)

    Greene, Daniel J; Elshafei, Ahmed; Nyame, Yaw A; Kara, Onder; Malkoc, Ercan; Gao, Tianming; Jones, J Stephen

    2016-08-01

    The aim of this study was to externally validate a previously developed PCA3-based nomogram for the prediction of prostate cancer (PCa) and high-grade (intermediate and/or high-grade) prostate cancer (HGPCa) at the time of initial prostate biopsy. A retrospective review was performed on a cohort of 336 men from a large urban academic medical center. All men had serum PSA PCa, PSA at diagnosis, PCA3, total prostate volume (TPV), and abnormal finding on digital rectal exam (DRE). These variables were used to test the accuracy (concordance index) and calibration of a previously published PCA3 nomogram. Biopsy confirms PCa and HGPCa in 51.0% and 30.4% of validation patients, respectively. This differed from the original cohort in that it had significantly more PCa and HGPCA (51% vs. 44%, P = 0.019; and 30.4% vs. 19.1%, P PCa detection the concordance index was 75% and 77% for overall PCa and HGPCa, respectively. Calibration for overall PCa was good. This represents the first external validation of a PCA3-based prostate cancer predictive nomogram in a North American population. Prostate 76:1019-1023, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  8. Structure-independent cross-validation between residual dipolar couplings originating from internal and external orienting media

    International Nuclear Information System (INIS)

    Barbieri, Renato; Bertini, Ivano; Lee, Yong-Min; Luchinat, Claudio; Velders, Aldrik H.

    2002-01-01

    Lanthanide-substituted calcium binding proteins are known to partially orient in high magnetic fields. Orientation provides residual dipolar couplings (rdc's). Two of these systems, Tm 3+ - and Dy 3+ -substituted calbindin D 9k , dissolved in an external orienting medium (nonionic liquid crystalline phase) provide rdc values which are the sum of those induced by the lanthanides and by the liquid crystalline phase on the native calcium binding protein. This structure-independent check shows the innocence of the orienting medium with respect to the structure of the protein in solution. Furthermore, the simultaneous use of lanthanide substitution and external orienting media provides a further effective tool to control and tune the orientation tensor

  9. External validation of a clinical prediction rule to predict full recovery and ongoing moderate/severe disability following acute whiplash injury.

    Science.gov (United States)

    Ritchie, Carrie; Hendrikz, Joan; Jull, Gwendolen; Elliott, James; Sterling, Michele

    2015-04-01

    Retrospective secondary analysis of data. To investigate the external validity of the whiplash clinical prediction rule (CPR). We recently derived a whiplash CPR to consolidate previously established prognostic factors for poor recovery from a whiplash injury and predicted 2 recovery pathways. Prognostic factors for full recovery were being less than 35 years of age and having an initial Neck Disability Index (NDI) score of 32% or less. Prognostic factors for ongoing moderate/severe pain and disability were being 35 years of age or older, having an initial NDI score of 40% or more, and the presence of hyperarousal symptoms. Validation is required to confirm the reproducibility and accuracy of this CPR. Clinician feedback on the usefulness of the CPR is also important to gauge acceptability. A secondary analysis of data from 101 individuals with acute whiplash-associated disorder who had previously participated in either a randomized controlled clinical trial or prospective cohort study was performed using accuracy statistics. Full recovery was defined as NDI score at 6 months of 10% or less, and ongoing moderate/severe pain and disability were defined as an NDI score at 6 months of 30% or greater. In addition, a small sample of physical therapists completed an anonymous survey on the clinical acceptability and usability of the tool. Results The positive predictive value of ongoing moderate/severe pain and disability was 90.9% in the validation cohort, and the positive predictive value of full recovery was 80.0%. Surveyed physical therapists reported that the whiplash CPR was simple, understandable, would be easy to use, and was an acceptable prognostic tool. External validation of the whiplash CPR confirmed the reproducibility and accuracy of this dual-pathway tool for individuals with acute whiplash-associated disorder. Further research is needed to assess prospective validation, the impact of inclusion on practice, and to examine the efficacy of linking treatment

  10. External validation of a biomarker and clinical prediction model for hospital mortality in acute respiratory distress syndrome.

    Science.gov (United States)

    Zhao, Zhiguo; Wickersham, Nancy; Kangelaris, Kirsten N; May, Addison K; Bernard, Gordon R; Matthay, Michael A; Calfee, Carolyn S; Koyama, Tatsuki; Ware, Lorraine B

    2017-08-01

    Mortality prediction in ARDS is important for prognostication and risk stratification. However, no prediction models have been independently validated. A combination of two biomarkers with age and APACHE III was superior in predicting mortality in the NHLBI ARDSNet ALVEOLI trial. We validated this prediction tool in two clinical trials and an observational cohort. The validation cohorts included 849 patients from the NHLBI ARDSNet Fluid and Catheter Treatment Trial (FACTT), 144 patients from a clinical trial of sivelestat for ARDS (STRIVE), and 545 ARDS patients from the VALID observational cohort study. To evaluate the performance of the prediction model, the area under the receiver operating characteristic curve (AUC), model discrimination, and calibration were assessed, and recalibration methods were applied. The biomarker/clinical prediction model performed well in all cohorts. Performance was better in the clinical trials with an AUC of 0.74 (95% CI 0.70-0.79) in FACTT, compared to 0.72 (95% CI 0.67-0.77) in VALID, a more heterogeneous observational cohort. The AUC was 0.73 (95% CI 0.70-0.76) when FACTT and VALID were combined. We validated a mortality prediction model for ARDS that includes age, APACHE III, surfactant protein D, and interleukin-8 in a variety of clinical settings. Although the model performance as measured by AUC was lower than in the original model derivation cohort, the biomarker/clinical model still performed well and may be useful for risk assessment for clinical trial enrollment, an issue of increasing importance as ARDS mortality declines, and better methods are needed for selection of the most severely ill patients for inclusion.

  11. Project on Elite Athlete Commitment (PEAK): III. An examination of the external validity across gender, and the expansion and clarification of the Sport Commitment Model.

    Science.gov (United States)

    Scanlan, Tara K; Russell, David G; Magyar, T Michelle; Scanlan, Larry A

    2009-12-01

    The Sport Commitment Model was further tested using the Scanlan Collaborative Interview Method to examine its generalizability to New Zealand's elite female amateur netball team, the Silver Ferns. Results supported or clarified Sport Commitment Model predictions, revealed avenues for model expansion, and elucidated the functions of perceived competence and enjoyment in the commitment process. A comparison and contrast of the in-depth interview data from the Silver Ferns with previous interview data from a comparable elite team of amateur male athletes allowed assessment of model external validity, tested the generalizability of the underlying mechanisms, and separated gender differences from discrepancies that simply reflected team or idiosyncratic differences.

  12. External validation of the Blunt Abdominal Trauma in Children (BATiC) score : Ruling out significant abdominal injury in children

    NARCIS (Netherlands)

    de Jong, Willem-Jan J.; Stoepker, Leon; Nellensteijn, David R.; Groen, Henk; El Moumni, Mostafa; Hulscher, Jan B.

    BACKGROUND: The aim of this study was to validate the use of the Blunt Abdominal Trauma in Children (BATiC) score. The BATiC score uses only readily available laboratory parameters, ultrasound results, and results from physical examination and does therefore not carry any risk of additional

  13. External Validation and Update of a Prediction Rule for the Duration of Sickness Absence Due to Common Mental Disorders

    NARCIS (Netherlands)

    Norder, Giny; Roelen, Corne A. M.; van der Klink, Jac J. L.; Bultmann, Ute; Sluiter, J. K.; Nieuwenhuijsen, K.

    Purpose The objective of the present study was to validate an existing prediction rule (including age, education, depressive/anxiety symptoms, and recovery expectations) for predictions of the duration of sickness absence due to common mental disorders (CMDs) and investigate the added value of

  14. Prognosis of patients with nonspecific neck pain: development and external validation of a prediction rule for persistence of complaints

    NARCIS (Netherlands)

    Schellingerhout, J.M.; Heijmans, M.W.; Verhagen, A.P.; Lewis, M.; de Vet, H.C.W.; Koes, B.W.

    2010-01-01

    Study Design.: Reanalysis of data from 3 randomized controlled trials. Objective.: Development and validation of a prediction rule that estimates the probability of complaints persisting for at least 6 months in patients presenting with nonspecific neck pain in primary care. Sumary of Background

  15. Examining Evidence for External and Consequential Validity of the First Term General Chemistry Exam from the ACS Examinations Institute

    Science.gov (United States)

    Lewis, Scott E.

    2014-01-01

    Validity of educational research instruments and student assessments has appropriately become a growing interest in the chemistry education research community. Of particular concern is an attention to the consequences to students that result from the interpretation of assessment scores and whether those consequences are swayed by invalidity within…

  16. STRUCTURE AND VALIDATION OF A CONTEXTUAL QUALITY OF LIFE SCALE FOR PEOPLE WITH INTELLECTUAL DISABILITIES IN SOCIAL SERVICES: AN ORGANIZATION-ORIENTED MEASURE FROM AN EXTERNAL PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Carolina Moliner

    2013-09-01

    Full Text Available The aim of this study is to develop and validate a scale on the Quality of Life (QoL of people with intellectual disabilities as assessed by family members (external perspective. The instrument measures improvement in QoL due to actions by organizations delivering services to individuals with intellectual disabilities (organization-oriented measure. In order to design the items for the scale, focus groups were set up with professionals dedicated to attending to individuals with intellectual disabilities. An initial scale of 20 items was constructed by consensus. A total of 1195 family members answered the questionnaire. In order to assess the structure of the scale, EFA recommended deleting 3 overlapping items. The final scale consisted of 17 items (α=95 and was composed of four main dimensions: self-determination (SD, social inclusion (SI, rights (RI and overall improvement (OI, which explained 74.83% of the variance. Finally, the consistency and validity were assessed. Convergent validity and discriminant validity were satisfactory. Moreover, CFA confirmed the structure of the scale. Main conclusions, limitations and practical implications are discussed.

  17. External Validation of a Case-Mix Adjustment Model for the Standardized Reporting of 30-Day Stroke Mortality Rates in China.

    Science.gov (United States)

    Yu, Ping; Pan, Yuesong; Wang, Yongjun; Wang, Xianwei; Liu, Liping; Ji, Ruijun; Meng, Xia; Jing, Jing; Tong, Xu; Guo, Li; Wang, Yilong

    2016-01-01

    A case-mix adjustment model has been developed and externally validated, demonstrating promise. However, the model has not been thoroughly tested among populations in China. In our study, we evaluated the performance of the model in Chinese patients with acute stroke. The case-mix adjustment model A includes items on age, presence of atrial fibrillation on admission, National Institutes of Health Stroke Severity Scale (NIHSS) score on admission, and stroke type. Model B is similar to Model A but includes only the consciousness component of the NIHSS score. Both model A and B were evaluated to predict 30-day mortality rates in 13,948 patients with acute stroke from the China National Stroke Registry. The discrimination of the models was quantified by c-statistic. Calibration was assessed using Pearson's correlation coefficient. The c-statistic of model A in our external validation cohort was 0.80 (95% confidence interval, 0.79-0.82), and the c-statistic of model B was 0.82 (95% confidence interval, 0.81-0.84). Excellent calibration was reported in the two models with Pearson's correlation coefficient (0.892 for model A, pcase-mix adjustment model could be used to effectively predict 30-day mortality rates in Chinese patients with acute stroke.

  18. External Validation of a Case-Mix Adjustment Model for the Standardized Reporting of 30-Day Stroke Mortality Rates in China.

    Directory of Open Access Journals (Sweden)

    Ping Yu

    Full Text Available A case-mix adjustment model has been developed and externally validated, demonstrating promise. However, the model has not been thoroughly tested among populations in China. In our study, we evaluated the performance of the model in Chinese patients with acute stroke.The case-mix adjustment model A includes items on age, presence of atrial fibrillation on admission, National Institutes of Health Stroke Severity Scale (NIHSS score on admission, and stroke type. Model B is similar to Model A but includes only the consciousness component of the NIHSS score. Both model A and B were evaluated to predict 30-day mortality rates in 13,948 patients with acute stroke from the China National Stroke Registry. The discrimination of the models was quantified by c-statistic. Calibration was assessed using Pearson's correlation coefficient.The c-statistic of model A in our external validation cohort was 0.80 (95% confidence interval, 0.79-0.82, and the c-statistic of model B was 0.82 (95% confidence interval, 0.81-0.84. Excellent calibration was reported in the two models with Pearson's correlation coefficient (0.892 for model A, p<0.001; 0.927 for model B, p = 0.008.The case-mix adjustment model could be used to effectively predict 30-day mortality rates in Chinese patients with acute stroke.

  19. A general psychopathology factor (P factor) in children: Structural model analysis and external validation through familial risk and child global executive function.

    Science.gov (United States)

    Martel, Michelle M; Pan, Pedro M; Hoffmann, Maurício S; Gadelha, Ary; do Rosário, Maria C; Mari, Jair J; Manfro, Gisele G; Miguel, Eurípedes C; Paus, Tomás; Bressan, Rodrigo A; Rohde, Luis A; Salum, Giovanni A

    2017-01-01

    High rates of comorbidities and poor validity of disorder diagnostic criteria for mental disorders hamper advances in mental health research. Recent work has suggested the utility of continuous cross-cutting dimensions, including general psychopathology and specific factors of externalizing and internalizing (e.g., distress and fear) syndromes. The current study evaluated the reliability of competing structural models of psychopathology and examined external validity of the best fitting model on the basis of family risk and child global executive function (EF). A community sample of 8,012 families from Brazil with children ages 6-12 years completed structured interviews about the child and parental psychiatric syndromes, and a subsample of 2,395 children completed tasks assessing EF (i.e., working memory, inhibitory control, and time processing). Confirmatory factor analyses tested a series of structural models of psychopathology in both parents and children. The model with a general psychopathology factor ("P factor") with 3 specific factors (fear, distress, and externalizing) exhibited the best fit. The general P factor accounted for most of the variance in all models, with little residual variance explained by each of the 3 specific factors. In addition, associations between child and parental factors were mainly significant for the P factors and nonsignificant for the specific factors from the respective models. Likewise, the child P factor-but not the specific factors-was significantly associated with global child EF. Overall, our results provide support for a latent overarching P factor characterizing child psychopathology, supported by familial associations and child EF. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  20. External validation of three dimensional conformal radiotherapy based NTCP models for patient-rated xerostomia and sticky saliva among patients treated with intensity modulated radiotherapy

    International Nuclear Information System (INIS)

    Beetz, Ivo; Schilstra, Cornelis; Luijk, Peter van; Christianen, Miranda E.M.C.; Doornaert, Patricia; Bijl, Henk P.; Chouvalova, Olga; Heuvel, Edwin R. van den; Steenbakkers, Roel J.H.M.; Langendijk, Johannes A.

    2012-01-01

    Purpose: The purpose of this study was to investigate the ability of predictive models for patient-rated xerostomia (XER 6M ) and sticky saliva (STIC 6M ) at 6 months after completion of primary (chemo)radiation developed in head and neck cancer patients treated with 3D-conformal radiotherapy (3D-CRT) to predict outcome in patients treated with intensity modulated radiotherapy (IMRT). Methods and materials: Recently, we published the results of a prospective study on predictive models for patient-rated xerostomia and sticky saliva in head and neck cancer patients treated with 3D-CRT (3D-CRT based NTCP models). The 3D-CRT based model for XER 6M consisted of three factors, including the mean parotid dose, age, and baseline xerostomia (none versus a bit). The 3D-CRT based model for STIC 6M consisted of the mean submandibular dose, age, the mean sublingual dose, and baseline sticky saliva (none versus a bit). In the current study, a population consisting of 162 patients treated with IMRT was used to test the external validity of these 3D-CRT based models. External validity was described by the explained variation (R 2 Nagelkerke) and the Brier score. The discriminative abilities of the models were calculated using the area under the receiver operating curve (AUC) and calibration (i.e. the agreement between predicted and observed outcome) was assessed with the Hosmer–Lemeshow “goodness-of-fit” test. Results: Overall model performance of the 3D-CRT based predictive models for XER 6M and STIC 6M was significantly worse in terms of the Brier score and R 2 Nagelkerke among patients treated with IMRT. Moreover the AUC for both 3D-CRT based models in the IMRT treated patients were markedly lower. The Hosmer–Lemeshow test showed a significant disagreement for both models between predicted risk and observed outcome. Conclusion: 3D-CRT based models for patient-rated xerostomia and sticky saliva among head and neck cancer patients treated with primary radiotherapy or

  1. Development and External Validation of Prognostic Model for 2-Year Survival of Non-Small-Cell Lung Cancer Patients Treated With Chemoradiotherapy

    International Nuclear Information System (INIS)

    Dehing-Oberije, Cary; Yu Shipeng; De Ruysscher, Dirk; Meersschout, Sabine; Van Beek, Karen; Lievens, Yolande; Van Meerbeeck, Jan; De Neve, Wilfried; Rao, Bharat Ph.D.; Weide, Hiska van der; Lambin, Philippe

    2009-01-01

    Purpose: Radiotherapy, combined with chemotherapy, is the treatment of choice for a large group of non-small-cell lung cancer (NSCLC) patients. Recent developments in the treatment of these patients have led to improved survival. However, the clinical TNM stage is highly inaccurate for the prediction of survival, and alternatives are lacking. The objective of this study was to develop and validate a prediction model for survival of NSCLC patients, treated with chemoradiotherapy. Patients and Methods: The clinical data from 377 consecutive inoperable NSCLC patients, Stage I-IIIB, treated radically with chemoradiotherapy were collected. A prognostic model for 2-year survival was developed, using 2-norm support vector machines. The performance of the model was expressed as the area under the curve of the receiver operating characteristic and assessed using leave-one-out cross-validation, as well as two external data sets. Results: The final multivariate model consisted of gender, World Health Organization performance status, forced expiratory volume in 1 s, number of positive lymph node stations, and gross tumor volume. The area under the curve, assessed by leave-one-out cross-validation, was 0.74, and application of the model to the external data sets yielded an area under the curve of 0.75 and 0.76. A high- and low-risk group could be clearly identified using a risk score based on the model. Conclusion: The multivariate model performed very well and was able to accurately predict the 2-year survival of NSCLC patients treated with chemoradiotherapy. The model could support clinicians in the treatment decision-making process.

  2. External validation of leukocytosis and neutrophilia as a prognostic marker in anal carcinoma treated with definitive chemoradiation.

    Science.gov (United States)

    Schernberg, Antoine; Huguet, Florence; Moureau-Zabotto, Laurence; Chargari, Cyrus; Rivin Del Campo, Eleonor; Schlienger, Michel; Escande, Alexandre; Touboul, Emmanuel; Deutsch, Eric

    2017-07-01

    To validate the prognostic value of leukocyte disorders in anal squamous cell carcinoma (SCC) patients receiving definitive concurrent chemoradiation. Bi-institutional clinical records from consecutive patients treated between 2001 and 2015 with definitive chemoradiation for anal SCC were retrospectively reviewed. Prognostic value of pretreatment leukocyte disorders was examined, with focus on patterns of relapse and survival. Leukocytosis and neutrophilia were defined as leukocyte or neutrophil count exceeding 10G/L and 7G/L, respectively. We identified 133 patients, treated in two institutions. Eight% and 7% displayed baseline leukocytosis and neutrophilia, respectively. Estimated 3-year overall survival (OS) and progression-free survival (PFS) were 88% and 77%, respectively. In univariate analysis, both leukocytosis and neutrophilia were associated with worse OS, PFS (p<0.01), locoregional control (LRC) and Distant Metastasis Control (DMC) (p<0.05), also after stratification by each institution. In multivariate analysis, leukocytosis and neutrophilia remained as independent risk factors associated with poorer OS, PFS, LRC and DMC (p<0.05). This study validates leukocytosis and neutrophilia as independent prognostic factors in anal SCC patients treated with definitive chemoradiation. Although prospective confirmation is warranted, it is suggested that the leukocyte and neutrophil count parameters are clinically relevant biomarkers to be considered for further clinical investigations. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Unavailability of thymidine kinase does not preclude the use of German comprehensive prognostic index: results of an external validation analysis in early chronic lymphocytic leukemia and comparison with MD Anderson Cancer Center model.

    Science.gov (United States)

    Molica, Stefano; Giannarelli, Diana; Mirabelli, Rosanna; Levato, Luciano; Russo, Antonio; Linardi, Maria; Gentile, Massimo; Morabito, Fortunato

    2016-01-01

    A comprehensive prognostic index that includes clinical (i.e., age, sex, ECOG performance status), serum (i.e., ß2-microglobulin, thymidine kinase [TK]), and molecular (i.e., IGVH mutational status, del 17p, del 11q) markers developed by the German CLL Study Group (GCLLSG) was externally validated in a prospective, community-based cohort consisting of 338 patients with early chronic lymphocytic leukemia (CLL) using as endpoint the time to first treatment (TTFT). Because serum TK was not available, a slightly modified version of the model based on seven instead of eight prognostic variables was used. By German index, 62.9% of patients were scored as having low-risk CLL (score 0-2), whereas 37.1% had intermediate-risk CLL (score 3-5). This stratification translated into a significant difference in the TTFT [HR = 4.21; 95% C.I. (2.71-6.53); P reliability [HR = 2.73; 95% C.I. (1.79-4.17); P German score. The c-statistic of the MDACC model was 0.65 (range, 0.53-0.78) a level below that of the German index [0.71 (range, 0.60-0.82)] and below the accepted 0.7 threshold necessary to have value at the individual patient level. Results of this external comparative validation analysis strongly support the German score as the benchmark for comparison of any novel prognostic scheme aimed at evaluating the TTFT in patients with early CLL even when a modified version which does not include TK is utilized. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. External validation of the DHAKA score and comparison with the current IMCI algorithm for the assessment of dehydration in children with diarrhoea: a prospective cohort study.

    Science.gov (United States)

    Levine, Adam C; Glavis-Bloom, Justin; Modi, Payal; Nasrin, Sabiha; Atika, Bita; Rege, Soham; Robertson, Sarah; Schmid, Christopher H; Alam, Nur H

    2016-10-01

    Dehydration due to diarrhoea is a leading cause of child death worldwide, yet no clinical tools for assessing dehydration have been validated in resource-limited settings. The Dehydration: Assessing Kids Accurately (DHAKA) score was derived for assessing dehydration in children with diarrhoea in a low-income country setting. In this study, we aimed to externally validate the DHAKA score in a new population of children and compare its accuracy and reliability to the current Integrated Management of Childhood Illness (IMCI) algorithm. DHAKA was a prospective cohort study done in children younger than 60 months presenting to the International Centre for Diarrhoeal Disease Research, Bangladesh, with acute diarrhoea (defined by WHO as three or more loose stools per day for less than 14 days). Local nurses assessed children and classified their dehydration status using both the DHAKA score and the IMCI algorithm. Serial weights were obtained and dehydration status was established by percentage weight change with rehydration. We did regression analyses to validate the DHAKA score and compared the accuracy and reliability of the DHAKA score and IMCI algorithm with receiver operator characteristic (ROC) curves and the weighted κ statistic. This study was registered with ClinicalTrials.gov, number NCT02007733. Between March 22, 2015, and May 15, 2015, 496 patients were included in our primary analyses. On the basis of our criterion standard, 242 (49%) of 496 children had no dehydration, 184 (37%) of 496 had some dehydration, and 70 (14%) of 496 had severe dehydration. In multivariable regression analyses, each 1-point increase in the DHAKA score predicted an increase of 0·6% in the percentage dehydration of the child and increased the odds of both some and severe dehydration by a factor of 1·4. Both the accuracy and reliability of the DHAKA score were significantly greater than those of the IMCI algorithm. The DHAKA score is the first clinical tool for assessing

  5. Development of Decision Support Formulas for the Prediction of Bladder Outlet Obstruction and Prostatic Surgery in Patients With Lower Urinary Tract Symptom/Benign Prostatic Hyperplasia: Part II, External Validation and Usability Testing of a Smartphone App

    Directory of Open Access Journals (Sweden)

    Min Soo Choo

    2017-04-01

    Full Text Available Purpose We aimed to externally validate the prediction model we developed for having bladder outlet obstruction (BOO and requiring prostatic surgery using 2 independent data sets from tertiary referral centers, and also aimed to validate a mobile app for using this model through usability testing. Methods Formulas and nomograms predicting whether a subject has BOO and needs prostatic surgery were validated with an external validation cohort from Seoul National University Bundang Hospital and Seoul Metropolitan Government-Seoul National University Boramae Medical Center between January 2004 and April 2015. A smartphone-based app was developed, and 8 young urologists were enrolled for usability testing to identify any human factor issues of the app. Results A total of 642 patients were included in the external validation cohort. No significant differences were found in the baseline characteristics of major parameters between the original (n=1,179 and the external validation cohort, except for the maximal flow rate. Predictions of requiring prostatic surgery in the validation cohort showed a sensitivity of 80.6%, a specificity of 73.2%, a positive predictive value of 49.7%, and a negative predictive value of 92.0%, and area under receiver operating curve of 0.84. The calibration plot indicated that the predictions have good correspondence. The decision curve showed also a high net benefit. Similar evaluation results using the external validation cohort were seen in the predictions of having BOO. Overall results of the usability test demonstrated that the app was user-friendly with no major human factor issues. Conclusions External validation of these newly developed a prediction model demonstrated a moderate level of discrimination, adequate calibration, and high net benefit gains for predicting both having BOO and requiring prostatic surgery. Also a smartphone app implementing the prediction model was user-friendly with no major human factor issue.

  6. Dengue score as a diagnostic predictor for pleural effusion and/or ascites: external validation and clinical application.

    Science.gov (United States)

    Suwarto, Suhendro; Hidayat, Mohammad Jauharsyah; Widjaya, Bing

    2018-02-23

    The Dengue Score is a model for predicting pleural effusion and/or ascites and uses the hematocrit (Hct), albumin concentration, platelet count and aspartate aminotransferase (AST) ratio as independent variables. As this metric has not been validated, we conducted a study to validate the Dengue Score and assess its clinical application. A retrospective study was performed at a private hospital in Jakarta, Indonesia. Patients with dengue infection hospitalized from January 2011 through March 2016 were included. The Dengue Score was calculated using four parameters: Hct increase≥15.1%, serum albumin≤3.49 mg/dL, platelet count≤49,500/μL and AST ratio ≥ 2.51. Each parameter was scored as 1 if present and 0 if absent. To validate the Dengue Score, goodness-of-fit was used to assess calibration, and the area under the receiver operating characteristic curve (AROC) was used to assess discrimination. Associations between clinical parameters and Dengue Score groups were determined by bivariate analysis. A total of 207 patients were included in this study. The calibration of the Dengue Score was acceptable (Hosmer-Lemeshow test, p = 0.11), and the score's discriminative ability was good (AROC = 0.88 (95% CI: 0.83-0.92)). At a cutoff of ≥2, the Dengue Score had a positive predictive value (PPV) of 79.03% and a negative predictive value (NPV) of 90.36% for the diagnostic prediction of pleural effusion and/or ascites. Compared with the Dengue Score ≤ 1 group, the Dengue Score = 2 group was significantly associated with hemoconcentration> 20% (p = 0.029), severe thrombocytopenia (p = 0.029), and increased length of hospital stay (p = 0.003). Compared with the Dengue Score = 2 group, the Dengue Score ≥ 3 group was significantly associated with hemoconcentration> 20% (p = 0.001), severe thrombocytopenia (p = 0.024), severe dengue (p = 0.039), and increased length of hospital stay (p = 0.011). The Dengue Score performed well and can

  7. Efficacy and External Validity of Electronic and Mobile Phone-Based Interventions Promoting Vegetable Intake in Young Adults: Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Nour, Monica; Chen, Juliana; Allman-Farinelli, Margaret

    2016-04-08

    Young adults (18-35 years) remain among the lowest vegetable consumers in many western countries. The digital era offers opportunities to engage this age group in interventions in new and appealing ways. This systematic review evaluated the efficacy and external validity of electronic (eHealth) and mobile phone (mHealth) -based interventions that promote vegetable intake in young adults. We searched several electronic databases for studies published between 1990 and 2015, and 2 independent authors reviewed the quality and risk of bias of the eligible papers and extracted data for analyses. The primary outcome of interest was the change in vegetable intake postintervention. Where possible, we calculated effect sizes (Cohen d and 95% CIs) for comparison. A random effects model was applied to the data for meta-analysis. Reach and representativeness of participants, intervention implementation, and program maintenance were assessed to establish external validity. Published validation studies were consulted to determine the validity of tools used to measure intake. We applied the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to evaluate the overall quality of the body of evidence. Of the 14 studies that met the selection criteria, we included 12 in the meta-analysis. In the meta-analysis, 7 studies found positive effects postintervention for fruit and vegetable intake, Cohen d 0.14-0.56 (pooled effect size 0.22, 95% CI 0.11-0.33, I(2)=68.5%, P=.002), and 4 recorded positive effects on vegetable intake alone, Cohen d 0.11-0.40 (pooled effect size 0.15, 95% CI 0.04-0.28, I(2)=31.4%, P=.2). These findings should be interpreted with caution due to variability in intervention design and outcome measures. With the majority of outcomes documented as a change in combined fruit and vegetable intake, it was difficult to determine intervention effects on vegetable consumption specifically. Measurement of intake was most commonly by self

  8. Predictive Accuracy of the PanCan Lung Cancer Risk Prediction Model -External Validation based on CT from the Danish Lung Cancer Screening Trial

    DEFF Research Database (Denmark)

    Winkler Wille, Mathilde M.; van Riel, Sarah J.; Saghir, Zaigham

    2015-01-01

    Objectives: Lung cancer risk models should be externally validated to test generalizability and clinical usefulness. The Danish Lung Cancer Screening Trial (DLCST) is a population-based prospective cohort study, used to assess the discriminative performances of the PanCan models. Methods: From...... the DLCST database, 1,152 nodules from 718 participants were included. Parsimonious and full PanCan risk prediction models were applied to DLCST data, and also coefficients of the model were recalculated using DLCST data. Receiver operating characteristics (ROC) curves and area under the curve (AUC) were...... used to evaluate risk discrimination. Results: AUCs of 0.826–0.870 were found for DLCST data based on PanCan risk prediction models. In the DLCST, age and family history were significant predictors (p = 0.001 and p = 0.013). Female sex was not confirmed to be associated with higher risk of lung cancer...

  9. Model-based clinical dose optimization for phenobarbital in neonates: An illustration of the importance of data sharing and external validation.

    Science.gov (United States)

    Völler, Swantje; Flint, Robert B; Stolk, Leo M; Degraeuwe, Pieter L J; Simons, Sinno H P; Pokorna, Paula; Burger, David M; de Groot, Ronald; Tibboel, Dick; Knibbe, Catherijne A J

    2017-11-15

    Particularly in the pediatric clinical pharmacology field, data-sharing offers the possibility of making the most of all available data. In this study, we utilize previously collected therapeutic drug monitoring (TDM) data of term and preterm newborns to develop a population pharmacokinetic model for phenobarbital. We externally validate the model using prospective phenobarbital data from an ongoing pharmacokinetic study in preterm neonates. TDM data from 53 neonates (gestational age (GA): 37 (24-42) weeks, bodyweight: 2.7 (0.45-4.5) kg; postnatal age (PNA): 4.5 (0-22) days) contained information on dosage histories, concentration and covariate data (including birth weight, actual weight, post-natal age (PNA), postmenstrual age, GA, sex, liver and kidney function, APGAR-score). Model development was carried out using NONMEM ® 7.3. After assessment of model fit, the model was validated using data of 17 neonates included in the DINO (Drug dosage Improvement in NeOnates)-study. Modelling of 229 plasma concentrations, ranging from 3.2 to 75.2mg/L, resulted in a one compartment model for phenobarbital. Clearance (CL) and volume (V d ) for a child with a birthweight of 2.6kg at PNA day 4.5 was 0.0091L/h (9%) and 2.38L (5%), respectively. Birthweight and PNA were the best predictors for CL maturation, increasing CL by 36.7% per kg birthweight and 5.3% per postnatal day of living, respectively. The best predictor for the increase in V d was actual bodyweight (0.31L/kg). External validation showed that the model can adequately predict the pharmacokinetics in a prospective study. Data-sharing can help to successfully develop and validate population pharmacokinetic models in neonates. From the results it seems that both PNA and bodyweight are required to guide dosing of phenobarbital in term and preterm neonates. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  10. External Validation of a Decision Tool To Guide Post-Operative Management of Patients with Secondary Peritonitis.

    Science.gov (United States)

    Atema, Jasper J; Ram, Kim; Schultz, Marcus J; Boermeester, Marja A

    Timely identification of patients in need of an intervention for abdominal sepsis after initial surgical management of secondary peritonitis is vital but complex. The aim of this study was to validate a decision tool for this purpose and to evaluate its potential to guide post-operative management. A prospective cohort study was conducted on consecutive adult patients undergoing surgery for secondary peritonitis in a single hospital. Assessments using the decision tool, based on one intra-operative and five post-operative variables, were performed on the second and third post-operative days and when the patients' clinical status deteriorated. Scores were compared with the clinical reference standard of persistent sepsis based on the clinical course or findings at imaging or surgery. Additionally, the potential of the decision tool to guide management in terms of diagnostic imaging in three previously defined score categories (low, intermediate, and high) was evaluated. A total of 161 assessments were performed in 69 patients. The majority of cases of secondary peritonitis (68%) were caused by perforation of the gastrointestinal tract. Post-operative persistent sepsis occurred in 28 patients. The discriminative capacity of the decision tool score was fair (area under the curve of the receiver operating characteristic = 0.79). The incidence rate differed significantly between the three score categories (p peritonitis, the decision tool score predicts with fair accuracy whether persistent sepsis is present.

  11. Multicenter external validation of two malignancy risk prediction models in patients undergoing 18F-FDG-PET for solitary pulmonary nodule evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Perandini, Simone; Soardi, G.A.; Signorini, M.; Motton, M.; Montemezzi, S. [Azienda Ospedaliera Universitaria Integrata di Verona, UOC Radiologia, Ospedale Maggiore di Borgo Trento, Verona (Italy); Larici, A.R.; Del Ciello, A. [Universita Cattolica del Sacro Cuore, Dipartimento di Scienze Radiologiche, Roma (Italy); Rizzardi, G. [Ospedale Humanitas Gavazzeni, UO Chirurgia Toracica, Bergamo (Italy); Solazzo, A. [Ospedale Humanitas Gavazzeni, UO Radiologia, Bergamo (Italy); Mancino, L.; Zeraj, F. [Ospedale dell' Angelo di Mestre, UO Pneumologia, Venezia (Italy); Bernhart, M. [Ospedale dell' Angelo di Mestre, UO Radiologia, Venezia (Italy)

    2017-05-15

    To achieve multicentre external validation of the Herder and Bayesian Inference Malignancy Calculator (BIMC) models. Two hundred and fifty-nine solitary pulmonary nodules (SPNs) collected from four major hospitals which underwent 18-FDG-PET characterization were included in this multicentre retrospective study. The Herder model was tested on all available lesions (group A). A subgroup of 180 SPNs (group B) was used to provide unbiased comparison between the Herder and BIMC models. Receiver operating characteristic (ROC) area under the curve (AUC) analysis was performed to assess diagnostic accuracy. Decision analysis was performed by adopting the risk threshold stated in British Thoracic Society (BTS) guidelines. Unbiased comparison performed In Group B showed a ROC AUC for the Herder model of 0.807 (95 % CI 0.742-0.862) and for the BIMC model of 0.822 (95 % CI 0.758-0.875). Both the Herder and the BIMC models were proven to accurately predict the risk of malignancy when tested on a large multicentre external case series. The BIMC model seems advantageous on the basis of a more favourable decision analysis. (orig.)

  12. Multicenter external validation of two malignancy risk prediction models in patients undergoing 18F-FDG-PET for solitary pulmonary nodule evaluation

    International Nuclear Information System (INIS)

    Perandini, Simone; Soardi, G.A.; Signorini, M.; Motton, M.; Montemezzi, S.; Larici, A.R.; Del Ciello, A.; Rizzardi, G.; Solazzo, A.; Mancino, L.; Zeraj, F.; Bernhart, M.

    2017-01-01

    To achieve multicentre external validation of the Herder and Bayesian Inference Malignancy Calculator (BIMC) models. Two hundred and fifty-nine solitary pulmonary nodules (SPNs) collected from four major hospitals which underwent 18-FDG-PET characterization were included in this multicentre retrospective study. The Herder model was tested on all available lesions (group A). A subgroup of 180 SPNs (group B) was used to provide unbiased comparison between the Herder and BIMC models. Receiver operating characteristic (ROC) area under the curve (AUC) analysis was performed to assess diagnostic accuracy. Decision analysis was performed by adopting the risk threshold stated in British Thoracic Society (BTS) guidelines. Unbiased comparison performed In Group B showed a ROC AUC for the Herder model of 0.807 (95 % CI 0.742-0.862) and for the BIMC model of 0.822 (95 % CI 0.758-0.875). Both the Herder and the BIMC models were proven to accurately predict the risk of malignancy when tested on a large multicentre external case series. The BIMC model seems advantageous on the basis of a more favourable decision analysis. (orig.)

  13. External validation and newly development of a nomogram to predict overall survival of abiraterone-treated, castration-resistant patients with metastatic prostate cancer

    Directory of Open Access Journals (Sweden)

    Yun-Jie Yang

    2018-01-01

    Full Text Available Abiraterone acetate is approved for the treatment of castration-resistant prostate cancer (CRPC; however, its effects vary. An accurate prediction model to identify patient groups that will benefit from abiraterone treatment is therefore urgently required. The Chi model exhibits a good profile for risk classification, although its utility for the chemotherapy-naive group is unclear. This study aimed to externally validate the Chi model and develop a new nomogram to predict overall survival (OS. We retrospectively analyzed a cohort of 110 patients. Patients were distributed among good-, intermediate-, and poor-risk groups, according to the Chi model. The good-, intermediate-, and poor-risk groups had a sample size of 59 (53.6%, 34 (30.9%, and 17 (15.5% in our dataset, and a median OS of 48.4, 29.1, and 10.5 months, respectively. The C-index of external validation of Chi model was 0.726. Univariate and multivariate analyses identified low hemoglobin concentrations (<110 g l−1, liver metastasis, and a short time interval from androgen deprivation therapy to abiraterone initiation (<36 months as predictors of OS. Accordingly, a new nomogram was developed with a C-index equal to 0.757 (95% CI, 0.678–0.836. In conclusion, the Chi model predicted the prognosis of abiraterone-treated, chemotherapy-naive patients with mCRPC, and we developed a new nomogram to predict the overall survival of this group of patients with less parameters.

  14. In-vivo dosimetry in external radiotherapy with amorphous silicon Portal Imaging Devices: from method to clinical validation

    International Nuclear Information System (INIS)

    Boissard, Philippe

    2012-01-01

    In vivo dose verification is used to prevent major deviations between the prescribed dose and the dose really delivered to the patient. This quality control was, nationally and internationally, widely recommended by scientific organizations. In France, its implementation and its use are now regulated. To do this, small detectors are fixed on the patient skin at the beginning of the treatment. However, the treatment delay is increased and not all treatment techniques could be assessed, such as IMRT plans (Intensity Modulated Radiation Therapy). In this context, Transit dosimetry performed with Electronic Portal Imaging Devices (EPIDs) appears as an interesting alternative for in vivo dose verification. During the treatment session, a transit dose is measured with the EPID, in two dimensions, and the dose in the patient is estimated from back projection of the portal dose. This work presents a quick and simple alternative method for verification of dose delivered to the patient using photon beams. Verifications in cases of complexes patient shapes and Intensity Modulated Radiation Therapy (IMRT) have been improved by using a Clarkson-Cunningham's integration method. 46 phantom test cases were designed to assess the accuracy of the method for 4, 6, 10 and 20 MV photon beams. For some points of interest the dose reconstructed by the method is compared to the dose measured with an ionization chamber. An additional in vivo uncertainty due to day to day deviations is defined and investigated. In the same time, a clinical study was driven during three years. In vivo dosimetry was performed for 494 patients treated for various tumors sites. Most of the patients were treated for a prostate cancer using IMRT. The in vivo dose is here compared to the dose calculated by the Treatment Planning System, TPS. The results of these two ways of validations are within the accepted tolerance of classical in vivo dosimetry. From the phantom study, we have estimated that the standard

  15. Validation and evaluation of measuring methods for the 3D documentation of external injuries in the field of forensic medicine.

    Science.gov (United States)

    Buck, Ursula; Buße, Kirsten; Campana, Lorenzo; Schyma, Christian

    2018-03-01

    Three-dimensional (3D) measurement techniques are gaining importance in many areas. The latest developments brought more cost-effective, user-friendly, and faster technologies onto the market. Which 3D techniques are suitable in the field of forensic medicine and what are their advantages and disadvantages? This wide-ranging study evaluated and validated various 3D measurement techniques for the forensic requirements. High-tech methods as well as low-budget systems have been tested and compared in terms of accuracy, ease of use, expenditure of time, mobility, cost, necessary knowhow, and their limitations. Within this study, various commercial measuring systems of the different techniques were tested. Based on the first results, one measuring system was selected for each technique, which appeared to be the most suitable for the forensic application or is already established in forensic medicine. A body of a deceased, a face and an injury of a living person, and a shoe sole were recorded by 11 people with different professions and previous knowledge using the selected systems. The results were assessed and the personal experiences were evaluated using a questionnaire. In addition, precision investigations were carried out using test objects. The study shows that the hand-held scanner and photogrammetry are very suitable for the 3D documentation of forensic medical findings. Their moderate acquisition costs and easy operation could lead to more frequent application in forensic medicine in the future. For special applications, the stripe-light scanner still has its justification due to its high precision, the flexible application area, and the high reliability. The results show that, thanks to the technological advances, the 3D measurement technology will have more and more impact on the routine of the forensic medical examination.

  16. Regional Externalities

    NARCIS (Netherlands)

    Heijman, W.J.M.

    2007-01-01

    The book offers practical and theoretical insights in regional externalities. Regional externalities are a specific subset of externalities that can be defined as externalities where space plays a dominant role. This class of externalities can be divided into three categories: (1) externalities

  17. External Validation of Health Economic Decision Models for Chronic Obstructive Pulmonary Disease (COPD): Report of the Third COPD Modeling Meeting.

    Science.gov (United States)

    Hoogendoorn, Martine; Feenstra, Talitha L; Asukai, Yumi; Briggs, Andrew H; Hansen, Ryan N; Leidl, Reiner; Risebrough, Nancy; Samyshkin, Yevgeniy; Wacker, Margarethe; Rutten-van Mölken, Maureen P M H

    2017-03-01

    To validate outcomes of presently available chronic obstructive pulmonary disease (COPD) cost-effectiveness models against results of two large COPD trials-the 3-year TOwards a Revolution in COPD Health (TORCH) trial and the 4-year Understanding Potential Long-term Impacts on Function with Tiotropium (UPLIFT) trial. Participating COPD modeling groups simulated the outcomes for the placebo-treated groups of the TORCH and UPLIFT trials using baseline characteristics of the trial populations as input. Groups then simulated treatment effectiveness by using relative reductions in annual decline in lung function and exacerbation frequency observed in the most intensively treated group compared with placebo as input for the models. Main outcomes were (change in) total/severe exacerbations and mortality. Furthermore, the absolute differences in total exacerbations and quality-adjusted life-years (QALYs) were used to approximate the cost per exacerbation avoided and the cost per QALY gained. Of the six participating models, three models reported higher total exacerbation rates than observed in the TORCH trial (1.13/patient-year) (models: 1.22-1.48). Four models reported higher rates than observed in the UPLIFT trial (0.85/patient-year) (models: 1.13-1.52). Two models reported higher mortality rates than in the TORCH trial (15.2%) (models: 20.0% and 30.6%) and the UPLIFT trial (16.3%) (models: 24.8% and 36.0%), whereas one model reported lower rates (9.8% and 12.1%, respectively). Simulation of treatment effectiveness showed that the absolute reduction in total exacerbations, the gain in QALYs, and the cost-effectiveness ratios did not differ from the trials, except for one model. Although most of the participating COPD cost-effectiveness models reported higher total exacerbation rates than observed in the trials, estimates of the absolute treatment effect and cost-effectiveness ratios do not seem different from the trials in most models. Copyright © 2017 International

  18. Predictive accuracy of the PanCan lung cancer risk prediction model - external validation based on CT from the Danish Lung Cancer Screening Trial

    International Nuclear Information System (INIS)

    Winkler Wille, Mathilde M.; Dirksen, Asger; Riel, Sarah J. van; Jacobs, Colin; Scholten, Ernst T.; Ginneken, Bram van; Saghir, Zaigham; Pedersen, Jesper Holst; Hohwue Thomsen, Laura; Skovgaard, Lene T.

    2015-01-01

    Lung cancer risk models should be externally validated to test generalizability and clinical usefulness. The Danish Lung Cancer Screening Trial (DLCST) is a population-based prospective cohort study, used to assess the discriminative performances of the PanCan models. From the DLCST database, 1,152 nodules from 718 participants were included. Parsimonious and full PanCan risk prediction models were applied to DLCST data, and also coefficients of the model were recalculated using DLCST data. Receiver operating characteristics (ROC) curves and area under the curve (AUC) were used to evaluate risk discrimination. AUCs of 0.826-0.870 were found for DLCST data based on PanCan risk prediction models. In the DLCST, age and family history were significant predictors (p = 0.001 and p = 0.013). Female sex was not confirmed to be associated with higher risk of lung cancer; in fact opposing effects of sex were observed in the two cohorts. Thus, female sex appeared to lower the risk (p = 0.047 and p = 0.040) in the DLCST. High risk discrimination was validated in the DLCST cohort, mainly determined by nodule size. Age and family history of lung cancer were significant predictors and could be included in the parsimonious model. Sex appears to be a less useful predictor. (orig.)

  19. Development and external validation of nomograms to predict the risk of skeletal metastasis at the time of diagnosis and skeletal metastasis-free survival in nasopharyngeal carcinoma.

    Science.gov (United States)

    Yang, Lin; Xia, Liangping; Wang, Yan; He, Shasha; Chen, Haiyang; Liang, Shaobo; Peng, Peijian; Hong, Shaodong; Chen, Yong

    2017-09-06

    The skeletal system is the most common site of distant metastasis in nasopharyngeal carcinoma (NPC); various prognostic factors have been reported for skeletal metastasis, though most studies have focused on a single factor. We aimed to establish nomograms to effectively predict skeletal metastasis at initial diagnosis (SMAD) and skeletal metastasis-free survival (SMFS) in NPC. A total of 2685 patients with NPC who received bone scintigraphy (BS) and/or 18F-deoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) and 2496 patients without skeletal metastasis were retrospectively assessed to develop individual nomograms for SMAD and SMFS. The models were validated externally using separate cohorts of 1329 and 1231 patients treated at two other institutions. Five independent prognostic factors were included in each nomogram. The SMAD nomogram had a significantly higher c-index than the TNM staging system (training cohort, P = 0.005; validation cohort, P system (P skeletal metastasis, which may improve counseling and facilitate individualized management of patients with NPC.

  20. Predictive accuracy of the PanCan lung cancer risk prediction model - external validation based on CT from the Danish Lung Cancer Screening Trial

    Energy Technology Data Exchange (ETDEWEB)

    Winkler Wille, Mathilde M.; Dirksen, Asger [Gentofte Hospital, Department of Respiratory Medicine, Hellerup (Denmark); Riel, Sarah J. van; Jacobs, Colin; Scholten, Ernst T.; Ginneken, Bram van [Radboud University Medical Center, Department of Radiology and Nuclear Medicine, Nijmegen (Netherlands); Saghir, Zaigham [Herlev Hospital, Department of Respiratory Medicine, Herlev (Denmark); Pedersen, Jesper Holst [Copenhagen University Hospital, Department of Thoracic Surgery, Rigshospitalet, Koebenhavn Oe (Denmark); Hohwue Thomsen, Laura [Hvidovre Hospital, Department of Respiratory Medicine, Hvidovre (Denmark); Skovgaard, Lene T. [University of Copenhagen, Department of Biostatistics, Koebenhavn Oe (Denmark)

    2015-10-15

    Lung cancer risk models should be externally validated to test generalizability and clinical usefulness. The Danish Lung Cancer Screening Trial (DLCST) is a population-based prospective cohort study, used to assess the discriminative performances of the PanCan models. From the DLCST database, 1,152 nodules from 718 participants were included. Parsimonious and full PanCan risk prediction models were applied to DLCST data, and also coefficients of the model were recalculated using DLCST data. Receiver operating characteristics (ROC) curves and area under the curve (AUC) were used to evaluate risk discrimination. AUCs of 0.826-0.870 were found for DLCST data based on PanCan risk prediction models. In the DLCST, age and family history were significant predictors (p = 0.001 and p = 0.013). Female sex was not confirmed to be associated with higher risk of lung cancer; in fact opposing effects of sex were observed in the two cohorts. Thus, female sex appeared to lower the risk (p = 0.047 and p = 0.040) in the DLCST. High risk discrimination was validated in the DLCST cohort, mainly determined by nodule size. Age and family history of lung cancer were significant predictors and could be included in the parsimonious model. Sex appears to be a less useful predictor. (orig.)

  1. Assessment of generalizability, applicability and predictability (GAP) for evaluating external validity in studies of universal family-based prevention of alcohol misuse in young people: systematic methodological review of randomized controlled trials.

    Science.gov (United States)

    Fernandez-Hermida, Jose Ramon; Calafat, Amador; Becoña, Elisardo; Tsertsvadze, Alexander; Foxcroft, David R

    2012-09-01

    To assess external validity characteristics of studies from two Cochrane Systematic Reviews of the effectiveness of universal family-based prevention of alcohol misuse in young people. Two reviewers used an a priori developed external validity rating form and independently assessed three external validity dimensions of generalizability, applicability and predictability (GAP) in randomized controlled trials. The majority (69%) of the included 29 studies were rated 'unclear' on the reporting of sufficient information for judging generalizability from sample to study population. Ten studies (35%) were rated 'unclear' on the reporting of sufficient information for judging applicability to other populations and settings. No study provided an assessment of the validity of the trial end-point measures for subsequent mortality, morbidity, quality of life or other economic or social outcomes. Similarly, no study reported on the validity of surrogate measures using established criteria for assessing surrogate end-points. Studies evaluating the benefits of family-based prevention of alcohol misuse in young people are generally inadequate at reporting information relevant to generalizability of the findings or implications for health or social outcomes. Researchers, study authors, peer reviewers, journal editors and scientific societies should take steps to improve the reporting of information relevant to external validity in prevention trials. © 2012 The Authors. Addiction © 2012 Society for the Study of Addiction.

  2. External Validation of Fatty Liver Index for Identifying Ultrasonographic Fatty Liver in a Large-Scale Cross-Sectional Study in Taiwan

    Science.gov (United States)

    Fang, Kuan-Chieh; Wang, Yuan-Chen; Huo, Teh-Ia; Huang, Yi-Hsiang; Yang, Hwai-I; Su, Chien-Wei; Lin, Han-Chieh; Lee, Fa-Yauh; Wu, Jaw-Ching; Lee, Shou-Dong

    2015-01-01

    Background and Aims The fatty liver index (FLI) is an algorithm involving the waist circumference, body mass index, and serum levels of triglyceride and gamma-glutamyl transferase to identify fatty liver. Although some studies have attempted to validate the FLI, few studies have been conducted for external validation among Asians. We attempted to validate FLI to predict ultrasonographic fatty liver in Taiwanese subjects. Methods We enrolled consecutive subjects who received health check-up services at the Taipei Veterans General Hospital from 2002 to 2009. Ultrasonography was applied to diagnose fatty liver. The ability of the FLI to detect ultrasonographic fatty liver was assessed by analyzing the area under the receiver operating characteristic (AUROC) curve. Results Among the 29,797 subjects enrolled in this study, fatty liver was diagnosed in 44.5% of the population. Subjects with ultrasonographic fatty liver had a significantly higher FLI than those without fatty liver by multivariate analysis (odds ratio 1.045; 95% confidence interval, CI 1.044–1.047, pfatty liver (AUROC: 0.827, 95% confidence interval, 0.822–0.831). An FLI fatty liver. Moreover, an FLI ≥ 35 (positive likelihood ratio (LR+) 3.12) for males and ≥ 20 (LR+ 4.43) for females rule in ultrasonographic fatty liver. Conclusions FLI could accurately identify ultrasonographic fatty liver in a large-scale population in Taiwan but with lower cut-off value than the Western population. Meanwhile the cut-off value was lower in females than in males. PMID:25781622

  3. External validation of fatty liver index for identifying ultrasonographic fatty liver in a large-scale cross-sectional study in Taiwan.

    Directory of Open Access Journals (Sweden)

    Bi-Ling Yang

    Full Text Available The fatty liver index (FLI is an algorithm involving the waist circumference, body mass index, and serum levels of triglyceride and gamma-glutamyl transferase to identify fatty liver. Although some studies have attempted to validate the FLI, few studies have been conducted for external validation among Asians. We attempted to validate FLI to predict ultrasonographic fatty liver in Taiwanese subjects.We enrolled consecutive subjects who received health check-up services at the Taipei Veterans General Hospital from 2002 to 2009. Ultrasonography was applied to diagnose fatty liver. The ability of the FLI to detect ultrasonographic fatty liver was assessed by analyzing the area under the receiver operating characteristic (AUROC curve.Among the 29,797 subjects enrolled in this study, fatty liver was diagnosed in 44.5% of the population. Subjects with ultrasonographic fatty liver had a significantly higher FLI than those without fatty liver by multivariate analysis (odds ratio 1.045; 95% confidence interval, CI 1.044-1.047, p< 0.001. Moreover, FLI had the best discriminative ability to identify patients with ultrasonographic fatty liver (AUROC: 0.827, 95% confidence interval, 0.822-0.831. An FLI < 25 (negative likelihood ratio (LR- 0.32 for males and <10 (LR- 0.26 for females rule out ultrasonographic fatty liver. Moreover, an FLI ≥ 35 (positive likelihood ratio (LR+ 3.12 for males and ≥ 20 (LR+ 4.43 for females rule in ultrasonographic fatty liver.FLI could accurately identify ultrasonographic fatty liver in a large-scale population in Taiwan but with lower cut-off value than the Western population. Meanwhile the cut-off value was lower in females than in males.

  4. Mapping the EORTC QLQ-C30 onto the EQ-5D-3L: assessing the external validity of existing mapping algorithms.

    Science.gov (United States)

    Doble, Brett; Lorgelly, Paula

    2016-04-01

    To determine the external validity of existing mapping algorithms for predicting EQ-5D-3L utility values from EORTC QLQ-C30 responses and to establish their generalizability in different types of cancer. A main analysis (pooled) sample of 3560 observations (1727 patients) and two disease severity patient samples (496 and 93 patients) with repeated observations over time from Cancer 2015 were used to validate the existing algorithms. Errors were calculated between observed and predicted EQ-5D-3L utility values using a single pooled sample and ten pooled tumour type-specific samples. Predictive accuracy was assessed using mean absolute error (MAE) and standardized root-mean-squared error (RMSE). The association between observed and predicted EQ-5D utility values and other covariates across the distribution was tested using quantile regression. Quality-adjusted life years (QALYs) were calculated using observed and predicted values to test responsiveness. Ten 'preferred' mapping algorithms were identified. Two algorithms estimated via response mapping and ordinary least-squares regression using dummy variables performed well on number of validation criteria, including accurate prediction of the best and worst QLQ-C30 health states, predicted values within the EQ-5D tariff range, relatively small MAEs and RMSEs, and minimal differences between estimated QALYs. Comparison of predictive accuracy across ten tumour type-specific samples highlighted that algorithms are relatively insensitive to grouping by tumour type and affected more by differences in disease severity. Two of the 'preferred' mapping algorithms suggest more accurate predictions, but limitations exist. We recommend extensive scenario analyses if mapped utilities are used in cost-utility analyses.

  5. Development and External Validation of the Korean Prostate Cancer Risk Calculator for High-Grade Prostate Cancer: Comparison with Two Western Risk Calculators in an Asian Cohort.

    Science.gov (United States)

    Park, Jae Young; Yoon, Sungroh; Park, Man Sik; Choi, Hoon; Bae, Jae Hyun; Moon, Du Geon; Hong, Sung Kyu; Lee, Sang Eun; Park, Chanwang; Byun, Seok-Soo

    2017-01-01

    We developed the Korean Prostate Cancer Risk Calculator for High-Grade Prostate Cancer (KPCRC-HG) that predicts the probability of prostate cancer (PC) of Gleason score 7 or higher at the initial prostate biopsy in a Korean cohort (http://acl.snu.ac.kr/PCRC/RISC/). In addition, KPCRC-HG was validated and compared with internet-based Western risk calculators in a validation cohort. Using a logistic regression model, KPCRC-HG was developed based on the data from 602 previously unscreened Korean men who underwent initial prostate biopsies. Using 2,313 cases in a validation cohort, KPCRC-HG was compared with the European Randomized Study of Screening for PC Risk Calculator for high-grade cancer (ERSPCRC-HG) and the Prostate Cancer Prevention Trial Risk Calculator 2.0 for high-grade cancer (PCPTRC-HG). The predictive accuracy was assessed using the area under the receiver operating characteristic curve (AUC) and calibration plots. PC was detected in 172 (28.6%) men, 120 (19.9%) of whom had PC of Gleason score 7 or higher. Independent predictors included prostate-specific antigen levels, digital rectal examination findings, transrectal ultrasound findings, and prostate volume. The AUC of the KPCRC-HG (0.84) was higher than that of the PCPTRC-HG (0.79, pexternal validation. Calibration plots also revealed better performance of KPCRC-HG and ERSPCRC-HG than that of PCPTRC-HG on external validation. At a cut-off of 5% for KPCRC-HG, 253 of the 2,313 men (11%) would not have been biopsied, and 14 of the 614 PC cases with Gleason score 7 or higher (2%) would not have been diagnosed. KPCRC-HG is the first web-based high-grade prostate cancer prediction model in Korea. It had higher predictive accuracy than PCPTRC-HG in a Korean population and showed similar performance with ERSPCRC-HG in a Korean population. This prediction model could help avoid unnecessary biopsy and reduce overdiagnosis and overtreatment in clinical settings.

  6. Efficacy and External Validity of Electronic and Mobile Phone-Based Interventions Promoting Vegetable Intake in Young Adults: A Systematic Review Protocol.

    Science.gov (United States)

    Nour, Monica Marina; Chen, Juliana; Allman-Farinelli, Margaret

    2015-07-28

    Despite social marketing campaigns and behavior change interventions, young adults remain among the lowest consumers of vegetables. The digital era offers potential new avenues for both social marketing and individually tailored programs, through texting, web, and mobile applications. The effectiveness and generalizability of such programs have not been well documented. The aim of this systematic review is to evaluate the efficacy and external validity of social marketing, electronic, and mobile phone-based (mHealth) interventions aimed at increasing vegetable intake in young adults. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) protocol will be used to conduct this systematic review. The search strategy will be executed across eleven electronic databases using combinations of the following search terms: "online intervention", "computer-assisted therapy", "internet", "website", "cell phones", "cyber", "telemedicine", "email", "social marketing", "social media", "mass media", "young adult", and "fruit and vegetables". The reference lists of included studies will also be searched for additional citations. Titles and abstracts will be screened against inclusion criteria and full texts of potentially eligible papers will be assessed by two independent reviewers. Data from eligible papers will be extracted. Quality and risk of bias will be assessed using the Effective Public Health Practice Project (EPHPP) Quality Assessment Tool for Quantitative Studies and The Cochrane Collaboration Risk of Bias assessment tool respectively. The external validity of the studies will be determined based on components such as reach, adoption, and representativeness of participants; intervention implementation and adaption; and program maintenance and institutionalization. Results will be reported quantitatively and qualitatively. Our research is in progress. A draft of the systematic review is currently being produced for publication by the end of 2015

  7. External Validation of the Prestroke Independence, Sex, Age, National Institutes of Health Stroke Scale Score for Predicting Pneumonia After Stroke Using Data From the China National Stroke Registry.

    Science.gov (United States)

    Zhang, Runhua; Ji, Ruijun; Pan, Yuesong; Jiang, Yong; Liu, Gaifen; Wang, Yilong; Wang, Yongjun

    2017-05-01

    Pneumonia is an important risk factor for mortality and morbidity after stroke. The Prestroke Independence, Sex, Age, National Institutes of Health Stroke Scale (ISAN) score was shown to be a useful tool for predicting stroke-associated pneumonia based on UK multicenter cohort study. We aimed to externally validate the score using data from the China National Stroke Registry (CNSR). Eligible patients with acute ischemic stroke (AIS) and intracerebral hemorrhage (ICH) in the CNSR from 2007 to 2008 were included. The area under the receiver operating characteristic (AUC) curve was used to evaluate discrimination. The Hosmer-Lemeshow goodness of fit test and Pearson correlation coefficient were performed to assess calibration of the model. A total of 19,333 patients (AIS = 14400; ICH = 4933) were included and the overall pneumonia rate was 12.7%. The AUC was .76 (95% confidence interval [CI]: .75-.78) for the subgroup of AIS and .70 (95% CI: .68-.72) for the subgroup of ICH. The Hosmer-Lemeshow test showed the ISAN score with the good calibration for AIS and ICH (P = .177 and .405, respectively). The plot of observed versus predicted pneumonia rates suggested higher correlation for patients with AIS than with ICH (Pearson correlation coefficient = .99 and .83, respectively). The ISAN score was a useful tool for predicting in-hospital pneumonia after acute stroke, especially for patients with AIS. Further validations need to be done in different populations. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  8. International External Validation Study of the 2014 European Society of Cardiology Guidelines on Sudden Cardiac Death Prevention in Hypertrophic Cardiomyopathy (EVIDENCE-HCM).

    Science.gov (United States)

    O'Mahony, Constantinos; Jichi, Fatima; Ommen, Steve R; Christiaans, Imke; Arbustini, Eloisa; Garcia-Pavia, Pablo; Cecchi, Franco; Olivotto, Iacopo; Kitaoka, Hiroaki; Gotsman, Israel; Carr-White, Gerald; Mogensen, Jens; Antoniades, Loizos; Mohiddin, Saidi A; Maurer, Mathew S; Tang, Hak Chiaw; Geske, Jeffrey B; Siontis, Konstantinos C; Mahmoud, Karim D; Vermeer, Alexa; Wilde, Arthur; Favalli, Valentina; Guttmann, Oliver P; Gallego-Delgado, Maria; Dominguez, Fernando; Tanini, Ilaria; Kubo, Toru; Keren, Andre; Bueser, Teofila; Waters, Sarah; Issa, Issa F; Malcolmson, James; Burns, Tom; Sekhri, Neha; Hoeger, Christopher W; Omar, Rumana Z; Elliott, Perry M

    2018-03-06

    Identification of people with hypertrophic cardiomyopathy (HCM) who are at risk of sudden cardiac death (SCD) and require a prophylactic implantable cardioverter defibrillator is challenging. In 2014, the European Society of Cardiology proposed a new risk stratification method based on a risk prediction model (HCM Risk-SCD) that estimates the 5-year risk of SCD. The aim was to externally validate the 2014 European Society of Cardiology recommendations in a geographically diverse cohort of patients recruited from the United States, Europe, the Middle East, and Asia. This was an observational, retrospective, longitudinal cohort study. The cohort consisted of 3703 patients. Seventy three (2%) patients reached the SCD end point within 5 years of follow-up (5-year incidence, 2.4% [95% confidence interval {CI}, 1.9-3.0]). The validation study revealed a calibration slope of 1.02 (95% CI, 0.93-1.12), C-index of 0.70 (95% CI, 0.68-0.72), and D-statistic of 1.17 (95% CI, 1.05-1.29). In a complete case analysis (n= 2147; 44 SCD end points at 5 years), patients with a predicted 5-year risk of <4% (n=1524; 71%) had an observed 5-year SCD incidence of 1.4% (95% CI, 0.8-2.2); patients with a predicted risk of ≥6% (n=297; 14%) had an observed SCD incidence of 8.9% (95% CI, 5.96-13.1) at 5 years. For every 13 (297/23) implantable cardioverter defibrillator implantations in patients with an estimated 5-year SCD risk ≥6%, 1 patient can potentially be saved from SCD. This study confirms that the HCM Risk-SCD model provides accurate prognostic information that can be used to target implantable cardioverter defibrillator therapy in patients at the highest risk of SCD. © 2017 American Heart Association, Inc.

  9. External validation of the simple clinical score and the HOTEL score, two scores for predicting short-term mortality after admission to an acute medical unit.

    Science.gov (United States)

    Stræde, Mia; Brabrand, Mikkel

    2014-01-01

    Clinical scores can be of aid to predict early mortality after admission to a medical admission unit. A developed scoring system needs to be externally validated to minimise the risk of the discriminatory power and calibration to be falsely elevated. We performed the present study with the objective of validating the Simple Clinical Score (SCS) and the HOTEL score, two existing risk stratification systems that predict mortality for medical patients based solely on clinical information, but not only vital signs. Pre-planned prospective observational cohort study. Danish 460-bed regional teaching hospital. We included 3046 consecutive patients from 2 October 2008 until 19 February 2009. 26 (0.9%) died within one calendar day and 196 (6.4%) died within 30 days. We calculated SCS for 1080 patients. We found an AUROC of 0.960 (95% confidence interval [CI], 0.932 to 0.988) for 24-hours mortality and 0.826 (95% CI, 0.774-0.879) for 30-day mortality, and goodness-of-fit test, χ(2) = 2.68 (10 degrees of freedom), P = 0.998 and χ(2) = 4.00, P = 0.947, respectively. We included 1470 patients when calculating the HOTEL score. Discriminatory power (AUROC) was 0.931 (95% CI, 0.901-0.962) for 24-hours mortality and goodness-of-fit test, χ(2) = 5.56 (10 degrees of freedom), P = 0.234. We find that both the SCS and HOTEL scores showed an excellent to outstanding ability in identifying patients at high risk of dying with good or acceptable precision.

  10. Multi-Institutional External Validation of Seminal Vesicle Invasion Nomograms: Head-to-Head Comparison of Gallina Nomogram Versus 2007 Partin Tables

    International Nuclear Information System (INIS)

    Zorn, Kevin C.; Capitanio, Umberto; Jeldres, Claudio; Arjane, Philippe; Perrotte, Paul; Shariat, Shahrokh F.; Lee, David I.; Shalhav, Arieh L.; Zagaja, Gregory P.; Shikanov, Sergey A.; Gofrit, Ofer N.; Thong, Alan E.; Albala, David M.; Sun, Leon; Karakiewicz, Pierre I.

    2009-01-01

    Purpose: The Partin tables represent one of the most widely used prostate cancer staging tools for seminal vesicle invasion (SVI) prediction. Recently, Gallina et al. reported a novel staging tool for the prediction of SVI that further incorporated the use of the percentage of positive biopsy cores. We performed an external validation of the Gallina et al. nomogram and the 2007 Partin tables in a large, multi-institutional North American cohort of men treated with robotic-assisted radical prostatectomy. Methods and Materials: Clinical and pathologic data were prospectively gathered from 2,606 patients treated with robotic-assisted radical prostatectomy at one of four North American robotic referral centers between 2002 and 2007. Discrimination was quantified with the area under the receiver operating characteristics curve. The calibration compared the predicted and observed SVI rates throughout the entire range of predictions. Results: At robotic-assisted radical prostatectomy, SVI was recorded in 4.2% of patients. The discriminant properties of the Gallina et al. nomogram resulted in 81% accuracy compared with 78% for the 2007 Partin tables. The Gallina et al. nomogram overestimated the true rate of SVI. Conversely, the Partin tables underestimated the true rate of SVI. Conclusion: The Gallina et al. nomogram offers greater accuracy (81%) than the 2007 Partin tables (78%). However, both tools are associated with calibration limitations that need to be acknowledged and considered before their implementation into clinical practice.

  11. Predicting Failure in Early Acute Prosthetic Joint Infection Treated With Debridement, Antibiotics, and Implant Retention: External Validation of the KLIC Score.

    Science.gov (United States)

    Löwik, Claudia A M; Jutte, Paul C; Tornero, Eduard; Ploegmakers, Joris J W; Knobben, Bas A S; de Vries, Astrid J; Zijlstra, Wierd P; Dijkstra, Baukje; Soriano, Alex; Wouthuyzen-Bakker, Marjan

    2018-03-27

    Debridement, antibiotics, and implant retention (DAIR) is a widely used treatment modality for early acute prosthetic joint infection (PJI). A preoperative risk score was previously designed for predicting DAIR failure, consisting of chronic renal failure (K), liver cirrhosis (L), index surgery (I), cemented prosthesis (C), and C-reactive protein >115 mg/L (KLIC). The aim of this study was to validate the KLIC score in an external cohort. We retrospectively evaluated patients with early acute PJI treated with DAIR between 2006 and 2016 in 3 Dutch hospitals. Early acute PJI was defined as infection-related death within 60 days after debridement. A total of 386 patients were included. Failure occurred in 148 patients (38.3%). Patients with KLIC scores of ≤2, 2.5-3.5, 4-5, 5.5-6.5, and ≥7 had failure rates of 27.9%, 37.1%, 49.3%, 54.5%, and 85.7%, respectively (P < .001). The receiver-operating characteristic curve showed an area under the curve of 0.64 (95% confidence interval 0.59-0.69). A KLIC score higher than 6 points showed a specificity of 97.9%. The KLIC score is a relatively good preoperative risk score for DAIR failure in patients with early acute PJI and appears to be most useful in clinical practice for patients with low or high KLIC scores. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. SU-E-J-244: Development and Validation of a Knowledge Based Planning Model for External Beam Radiation Therapy of Locally Advanced Non-Small Cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Z; Kennedy, A [Sarah Cannon, Nashville, TN (United States); Larsen, E; Hayes, C; Grow, A [North Florida Cancer Center, Gainesville, FL (United States); Bahamondes, S.; Zheng, Y; Wu, X [JFK Comprehensive Cancer Institute, Lake Worth, FL (United States); Choi, M; Pai, S [Good Samaritan Hospital, Los Gatos, CA (United States); Li, J [Doctors Hospital of Augusta, Augusta, GA (United States); Cranford, K [Trident Medical Center, Charleston, SC (United States)

    2015-06-15

    Purpose: The study aims to develop and validate a knowledge based planning (KBP) model for external beam radiation therapy of locally advanced non-small cell lung cancer (LA-NSCLC). Methods: RapidPlan™ technology was used to develop a lung KBP model. Plans from 65 patients with LA-NSCLC were used to train the model. 25 patients were treated with VMAT, and the other patients were treated with IMRT. Organs-at-risk (OARs) included right lung, left lung, heart, esophagus, and spinal cord. DVH and geometric distribution DVH were extracted from the treated plans. The model was trained using principal component analysis and step-wise multiple regression. Box plot and regression plot tools were used to identify geometric outliers and dosimetry outliers and help fine-tune the model. The validation was performed by (a) comparing predicted DVH boundaries to actual DVHs of 63 patients and (b) using an independent set of treatment planning data. Results: 63 out of 65 plans were included in the final KBP model with PTV volume ranging from 102.5cc to 1450.2cc. Total treatment dose prescription varied from 50Gy to 70Gy based on institutional guidelines. One patient was excluded due to geometric outlier where 2.18cc of spinal cord was included in PTV. The other patient was excluded due to dosimetric outlier where the dose sparing to spinal cord was heavily enforced in the clinical plan. Target volume, OAR volume, OAR overlap volume percentage to target, and OAR out-of-field volume were included in the trained model. Lungs and heart had two principal component scores of GEDVH, whereas spinal cord and esophagus had three in the final model. Predicted DVH band (mean ±1 standard deviation) represented 66.2±3.6% of all DVHs. Conclusion: A KBP model was developed and validated for radiotherapy of LA-NSCLC in a commercial treatment planning system. The clinical implementation may improve the consistency of IMRT/VMAT planning.

  13. Contracting for Competitive Supply Chains under Network Externalities and Demand Uncertainty

    Directory of Open Access Journals (Sweden)

    Xiaojing Liu

    2016-01-01

    Full Text Available Based on network externalities and demand uncertainty environment, supply chain competition model is built; we identify the valid mechanism for the alternative range of profit-sharing contracts and also analyze the effect of product substitutability coefficient and network externalities on the alliance and profit-sharing contract. The results show that the vertical alliance contributes profit improvement to both the manufacturer and the retailer when the impact of network externalities on the product substitutability is not strong. However, vertical alliance will be out of operation when the effect of network externalities on the product substitutability is strong.

  14. External Validation and Evaluation of Reliability and Validity of the Modified Seoul National University Renal Stone Complexity Scoring System to Predict Stone-Free Status After Retrograde Intrarenal Surgery.

    Science.gov (United States)

    Park, Juhyun; Kang, Minyong; Jeong, Chang Wook; Oh, Sohee; Lee, Jeong Woo; Lee, Seung Bae; Son, Hwancheol; Jeong, Hyeon; Cho, Sung Yong

    2015-08-01

    The modified Seoul National University Renal Stone Complexity scoring system (S-ReSC-R) for retrograde intrarenal surgery (RIRS) was developed as a tool to predict stone-free rate (SFR) after RIRS. We externally validated the S-ReSC-R. We retrospectively reviewed 159 patients who underwent RIRS. The S-ReSC-R was assigned from 1 to 12 according to the location and number of sites involved. The stone-free status was defined as no evidence of a stone or with clinically insignificant residual fragment stones less than 2 mm. Interobserver and test-retest reliabilities were evaluated. Statistical performance of the prediction model was assessed by its predictive accuracy, predictive probability, and clinical usefulness. Overall SFR was 73.0%. The SFRs were 86.7%, 70.2%, and 48.6% in low-score (1-2), intermediate-score (3-4), and high-score (5-12) groups, respectively (pR revealed an area under the curve (AUC) of 0.731 (95% CI 0.650-0.813). The AUC of the three-titered S-ReSC-R was 0.701 (95% CI 0.609-0.794). The calibration plot showed that the predicted probability of SFR had a concordance comparable to that of observed frequency. The Hosmer-Lemeshow goodness of fit test revealed a p-value of 0.01 for the S-ReSC-R and 0.90 for the three-titered S-ReSC-R. Interobserver and test-retest reliabilities revealed an almost perfect level of agreement. The present study proved the predictive value of S-ReSC-R to predict SFR following RIRS in an independent cohort. Interobserver and test-retest reliabilities confirmed that S-ReSC-R was reliable and valid.

  15. External validation of the GrazeIn model of pasture dry matter intake and milk yield prediction for cows managed at different calving dates and stocking rates

    International Nuclear Information System (INIS)

    Roca-Fernández, A.I.; González-Rodríguez, A.

    2017-01-01

    The aim was to evaluate the prediction accuracy of pasture dry matter intake (PDMI) and milk yield (MY) predicted by the GrazeIn model using a database representing 124 PDMI measurements at paddock level and 2232 MY measurements at cow level. External validation of the model was conducted using data collected from a trial carried out with Holstein-Friesian cows (n=72) while grazed 28 paddocks and were managed in a 2×2 factorial design by considering two calving dates (CD), with different number of days in milk (DIM), early (E, 29 DIM) vs. middle (M, 167 DIM), and two stocking rates (SR), medium (M, 3.9 cows ha-1) vs. high (H, 4.8 cows ha-1), under a rotational grazing system. Cows were randomly assigned to four grazing scenarios (EM, EH, MM and MH). The mean observed PDMI of the total database was 14.2 kg DM cow-1 day-1 while GrazeIn predicted a mean PDMI for the database of 13.8 kg DM cow-1 day-1. The mean bias was −0.4 kg DM cow-1 day-1. GrazeIn predicted PDMI for the total database with a relative prediction error (RPE) of 10.0% at paddock level. The mean observed MY of the database was 23.2 kg cow-1 day-1 while GrazeIn predicted a MY for the database of 23.1 kg cow-1 day-1. The mean bias was –0.1 kg cow-1 day-1. GrazeIn predicted MY for the total database with a mean RPE of 17.3% at cow level. For the scenarios investigated, GrazeIn predicted PDMI and MY with a low level of error which made it a suitable tool for decision support systems.

  16. External validation of the PROFUND index in polypathological patients from internal medicine and acute geriatrics departments in Aragón.

    Science.gov (United States)

    Díez-Manglano, Jesús; Cabrerizo García, José Luis; García-Arilla Calvo, Ernesto; Jimeno Saínz, Araceli; Calvo Beguería, Eva; Martínez-Álvarez, Rosa M; Bejarano Tello, Esperanza; Caudevilla Martínez, Aránzazu

    2015-12-01

    The objective of the study was to validate externally and prospectively the PROFUND index to predict survival of polypathological patients after a year. An observational, prospective and multicenter study was performed. Polypathological patients admitted to an internal medicine or geriatrics department and attended by investigators consecutively between March 1 and June 30, 2011 were included. Data concerning age, gender, comorbidity, Barthel and Lawton-Brody indexes, Pfeiffer questionnaire, socio-familial Gijon scale, delirium, number of drugs and number of admissions during the previous year were gathered for each patient. The PROFUND index was calculated. The follow-up lasted 1 year. A Cox proportional regression model was calculated, and was used to analyze the association of the variables to mortality and C-statistic. 465 polypathological patients, 333 from internal medicine and 132 from geriatrics, were included. One-year mortality is associated with age [hazard ratio (HR) 1.52 95 % CI 1.04-2.12; p = 0.01], presence of neoplasia [HR 2.68 95 % CI 1.71-4.18; p = 0.0001] and dependence for basic activities of daily living [HR 2.34 95 % CI 1.61-3.40; p = 0.0009]. In predicting mortality, the PROFUND index shows good discrimination in patients from internal medicine (C-statistics 0.725 95 % CI 0.670-0.781), but a poor one in those from geriatrics (0.546 95 % CI 0.448-0.644). The PROFUND index is a reliable tool for predicting mortality in internal medicine PP patients.

  17. Performance of an easy-to-use prediction model for renal patient survival: an external validation study using data from the ERA-EDTA Registry.

    Science.gov (United States)

    Hemke, Aline C; Heemskerk, Martin B A; van Diepen, Merel; Kramer, Anneke; de Meester, Johan; Heaf, James G; Abad Diez, José Maria; Torres Guinea, Marta; Finne, Patrik; Brunet, Philippe; Vikse, Bjørn E; Caskey, Fergus J; Traynor, Jamie P; Massy, Ziad A; Couchoud, Cécile; Groothoff, Jaap W; Nordio, Maurizio; Jager, Kitty J; Dekker, Friedo W; Hoitsma, Andries J

    2018-01-16

    An easy-to-use prediction model for long-term renal patient survival based on only four predictors [age, primary renal disease, sex and therapy at 90 days after the start of renal replacement therapy (RRT)] has been developed in The Netherlands. To assess the usability of this model for use in Europe, we externally validated the model in 10 European countries. Data from the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry were used. Ten countries that reported individual patient data to the registry on patients starting RRT in the period 1995-2005 were included. Patients prediction model was evaluated for the 10- (primary endpoint), 5- and 3-year survival predictions by assessing the calibration and discrimination outcomes. We used a data set of 136 304 patients from 10 countries. The calibration in the large and calibration plots for 10 deciles of predicted survival probabilities showed average differences of 1.5, 3.2 and 3.4% in observed versus predicted 10-, 5- and 3-year survival, with some small variation on the country level. The concordance index, indicating the discriminatory power of the model, was 0.71 in the complete ERA-EDTA Registry cohort and varied according to country level between 0.70 and 0.75. A prediction model for long-term renal patient survival developed in a single country, based on only four easily available variables, has a comparably adequate performance in a wide range of other European countries. © The Author(s) 2018. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. External validation of the GrazeIn model of pasture dry matter intake and milk yield prediction for cows managed at different calving dates and stocking rates

    Energy Technology Data Exchange (ETDEWEB)

    Roca-Fernández, A.I.; González-Rodríguez, A.

    2017-07-01

    The aim was to evaluate the prediction accuracy of pasture dry matter intake (PDMI) and milk yield (MY) predicted by the GrazeIn model using a database representing 124 PDMI measurements at paddock level and 2232 MY measurements at cow level. External validation of the model was conducted using data collected from a trial carried out with Holstein-Friesian cows (n=72) while grazed 28 paddocks and were managed in a 2×2 factorial design by considering two calving dates (CD), with different number of days in milk (DIM), early (E, 29 DIM) vs. middle (M, 167 DIM), and two stocking rates (SR), medium (M, 3.9 cows ha-1) vs. high (H, 4.8 cows ha-1), under a rotational grazing system. Cows were randomly assigned to four grazing scenarios (EM, EH, MM and MH). The mean observed PDMI of the total database was 14.2 kg DM cow-1 day-1 while GrazeIn predicted a mean PDMI for the database of 13.8 kg DM cow-1 day-1. The mean bias was −0.4 kg DM cow-1 day-1. GrazeIn predicted PDMI for the total database with a relative prediction error (RPE) of 10.0% at paddock level. The mean observed MY of the database was 23.2 kg cow-1 day-1 while GrazeIn predicted a MY for the database of 23.1 kg cow-1 day-1. The mean bias was –0.1 kg cow-1 day-1. GrazeIn predicted MY for the total database with a mean RPE of 17.3% at cow level. For the scenarios investigated, GrazeIn predicted PDMI and MY with a low level of error which made it a suitable tool for decision support systems.

  19. Externalities - an analysis using the EU ExternE-results

    International Nuclear Information System (INIS)

    2003-10-01

    The EU project ExternE quantified the externalities for the different energy technologies. In this work, the ExternE results are used in a MARKAL-analysis for the Nordic countries. The analysis does not go into detail, but gives some interesting indications: The external costs are not fully covered in the Nordic energy systems, the present taxes and charges are not high enough. The emissions from the energy systems would be strongly reduced, if taxes/environmental charges were set at the level ExternE calculate. The emissions from power production would be reduced most. Renewable energy sources and natural gas dominate the energy systems in the ExternE case

  20. External validation of heart-type fatty acid binding protein, high-sensitivity cardiac troponin, and electrocardiography as rule-out for acute myocardial infarction.

    Science.gov (United States)

    Van Hise, Christopher B; Greenslade, Jaimi H; Parsonage, William; Than, Martin; Young, Joanna; Cullen, Louise

    2018-02-01

    To externally validate a clinical decision rule incorporating heart fatty acid binding protein (h-FABP), high-sensitivity troponin (hs-cTn) and electrocardiogram (ECG) for the detection of acute myocardial infarction (AMI) on presentation to the Emergency Department. We also investigated whether this clinical decision rule improved identification of AMI over algorithms incorporating hs-cTn and ECG only. This study included data from 789 patients from the Brisbane ADAPT cohort and 441 patients from the Christchurch TIMI RCT cohort. The primary outcome was index AMI. Sensitivity, specificity, positive predictive value and negative predictive value were used to assess the diagnostic accuracy of the algorithms. 1230 patients were recruited, including 112 (9.1%) with AMI. The algorithm including h-FABP and hs-cTnT had 100% sensitivity and 32.4% specificity. The algorithm utilising h-FABP and hs-cTnI had similar sensitivity (99.1%) and higher specificity (43.4%). The hs-cTnI and hs-cTnT algorithms without h-FABP both had a sensitivity of 98.2%; a result that was not significantly different from either algorithm incorporating h-FABP. Specificity was higher for the hs-cTnI algorithm (68.1%) compared to the hs-cTnT algorithm (33.0%). The specificity of the algorithm incorporating hs-cTnI alone was also significantly higher than both of the algorithms incorporating h-FABP (p<0.01). For patients presenting to the Emergency Department with chest pain, an algorithm incorporating h-FABP, hs-cTn and ECG has high accuracy and can rule out up to 40% of patients. An algorithm incorporating only hs-cTn and ECG has similar sensitivity and may rule out a higher proportion of patients. Each of the algorithms can be used to safely identify patients as low risk for AMI on presentation to the Emergency Department. Copyright © 2017 The Canadian Society of Clinical Chemists. All rights reserved.

  1. Evaluating the predictive accuracy and the clinical benefit of a nomogram aimed to predict survival in node-positive prostate cancer patients: External validation on a multi-institutional database.

    Science.gov (United States)

    Bianchi, Lorenzo; Schiavina, Riccardo; Borghesi, Marco; Bianchi, Federico Mineo; Briganti, Alberto; Carini, Marco; Terrone, Carlo; Mottrie, Alex; Gacci, Mauro; Gontero, Paolo; Imbimbo, Ciro; Marchioro, Giansilvio; Milanese, Giulio; Mirone, Vincenzo; Montorsi, Francesco; Morgia, Giuseppe; Novara, Giacomo; Porreca, Angelo; Volpe, Alessandro; Brunocilla, Eugenio

    2018-04-06

    To assess the predictive accuracy and the clinical value of a recent nomogram predicting cancer-specific mortality-free survival after surgery in pN1 prostate cancer patients through an external validation. We evaluated 518 prostate cancer patients treated with radical prostatectomy and pelvic lymph node dissection with evidence of nodal metastases at final pathology, at 10 tertiary centers. External validation was carried out using regression coefficients of the previously published nomogram. The performance characteristics of the model were assessed by quantifying predictive accuracy, according to the area under the curve in the receiver operating characteristic curve and model calibration. Furthermore, we systematically analyzed the specificity, sensitivity, positive predictive value and negative predictive value for each nomogram-derived probability cut-off. Finally, we implemented decision curve analysis, in order to quantify the nomogram's clinical value in routine practice. External validation showed inferior predictive accuracy as referred to in the internal validation (65.8% vs 83.3%, respectively). The discrimination (area under the curve) of the multivariable model was 66.7% (95% CI 60.1-73.0%) by testing with receiver operating characteristic curve analysis. The calibration plot showed an overestimation throughout the range of predicted cancer-specific mortality-free survival rates probabilities. However, in decision curve analysis, the nomogram's use showed a net benefit when compared with the scenarios of treating all patients or none. In an external setting, the nomogram showed inferior predictive accuracy and suboptimal calibration characteristics as compared to that reported in the original population. However, decision curve analysis showed a clinical net benefit, suggesting a clinical implication to correctly manage pN1 prostate cancer patients after surgery. © 2018 The Japanese Urological Association.

  2. Intermittency in Hall-magnetohydrodynamics with a strong guide field

    OpenAIRE

    Imazio, P. Rodriguez; Martin, L. N.; Dmitruk, P.; Mininni, P. D.

    2013-01-01

    We present a detailed study of intermittency in the velocity and magnetic field fluctuations of compressible Hall-magnetohydrodynamic turbulence with an external guide field. To solve the equations numerically, a reduced model valid when a strong guide field is present is used. Different values for the ion skin depth are considered in the simulations. The resulting data are analyzed computing field increments in several directions perpendicular to the guide field, and building structure funct...

  3. <strong>Mini-project>

    DEFF Research Database (Denmark)

    Katajainen, Jyrki

    2008-01-01

    In this project the goal is to develop the safe * family of containers for the CPH STL. The containers to be developed should be safer and more reliable than any of the existing implementations. A special focus should be put on strong exception safety since none of the existing prototypes available...

  4. The Prospective External Validation of International Ovarian Tumor Analysis (IOTA) Simple Rules in the Hands of Level I and II Examiners.

    Science.gov (United States)

    Knafel, A; Banas, T; Nocun, A; Wiechec, M; Jach, R; Ludwin, A; Kabzinska-Turek, M; Pietrus, M; Pitynski, K

    2016-10-01

    Objective: To externally validate the International Ovarian Tumor Analysis (IOTA) Simple Rules (SR) by examiners with different levels of sonographic experience defined by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) and to assess the morphological ultrasound features of the adnexal tumors classified as inconclusive based on IOTA SR. Materials and Methods: In the two-year prospective study adnexal tumors were assessed preoperatively with transvaginal ultrasound by examiners with different levels of experience (level 1- IOTA SR1, level 2-IOTA SR2). Additionally, an expert (level 3) evaluated all tumors by subjective assessment (SA). If the rules could not be applied, the tumors were considered inconclusive. The final diagnosis was based on the histopathological result of the removed mass. The diagnostic performance measures for the assessed model were sensitivity, specificity, negative (LR-) and positive(LR+) likelihood ratios, accuracy (ACC) and diagnostic odds ratio (DOR). Results: 226 women with adnexal tumors scheduled for surgery were included in the stutdy. The prevalence of malignancy was 36.3 % in the group of all studied tumors and was 52.5 % in the inconclusive group (n = 40) (p = 0.215). Fewer tumors were classified as inconclusive by level 2 examiners compared to level 1 examiners [20 (8.8 %) vs. 40 (17.7 %); p = 0.008], resulting from the discrepancy in the evaluation of acoustic shadows and the vascularization within the tumor. For level 1 examiners a diagnostic strategy using IOTA SR1 +MA (assuming malignancy when SR inconclusive) achieved a sensitivity, specificity and DOR of 96.3 %, 81.9 %, 13.624 respectively. For level 2 examiners the diagnostic strategy for IOTA SR2 +MA achieved a sensitivity, specificity and DOR of 95.1 %, 89.6 %, 137,143, respectively. Adding SA by an expert (or level 3 examiner) when IOTA SR were not applicable improved the specificity of the test and

  5. Strong interactions

    International Nuclear Information System (INIS)

    Froissart, Marcel

    1976-01-01

    Strong interactions are introduced by their more obvious aspect: nuclear forces. In hadron family, the nucleon octet, OMEGA - decuplet, and quark triply are successively considered. Pion wave having been put at the origin of nuclear forces, low energy phenomena are described, the force being explained as an exchange of structure corresponding to a Regge trajectory in a variable rotating state instead of the exchange of a well defined particle. At high energies the concepts of pomeron, parton and stratons are introduced, pionization and fragmentation are briefly differentiated [fr

  6. External validation of Vascular Study Group of New England risk predictive model of mortality after elective abdominal aorta aneurysm repair in the Vascular Quality Initiative and comparison against established models.

    Science.gov (United States)

    Eslami, Mohammad H; Rybin, Denis V; Doros, Gheorghe; Siracuse, Jeffrey J; Farber, Alik

    2018-01-01

    The purpose of this study is to externally validate a recently reported Vascular Study Group of New England (VSGNE) risk predictive model of postoperative mortality after elective abdominal aortic aneurysm (AAA) repair and to compare its predictive ability across different patients' risk categories and against the established risk predictive models using the Vascular Quality Initiative (VQI) AAA sample. The VQI AAA database (2010-2015) was queried for patients who underwent elective AAA repair. The VSGNE cases were excluded from the VQI sample. The external validation of a recently published VSGNE AAA risk predictive model, which includes only preoperative variables (age, gender, history of coronary artery disease, chronic obstructive pulmonary disease, cerebrovascular disease, creatinine levels, and aneurysm size) and planned type of repair, was performed using the VQI elective AAA repair sample. The predictive value of the model was assessed via the C-statistic. Hosmer-Lemeshow method was used to assess calibration and goodness of fit. This model was then compared with the Medicare, Vascular Governance Northwest model, and Glasgow Aneurysm Score for predicting mortality in VQI sample. The Vuong test was performed to compare the model fit between the models. Model discrimination was assessed in different risk group VQI quintiles. Data from 4431 cases from the VSGNE sample with the overall mortality rate of 1.4% was used to develop the model. The internally validated VSGNE model showed a very high discriminating ability in predicting mortality (C = 0.822) and good model fit (Hosmer-Lemeshow P = .309) among the VSGNE elective AAA repair sample. External validation on 16,989 VQI cases with an overall 0.9% mortality rate showed very robust predictive ability of mortality (C = 0.802). Vuong tests yielded a significant fit difference favoring the VSGNE over then Medicare model (C = 0.780), Vascular Governance Northwest (0.774), and Glasgow Aneurysm Score (0

  7. Prognostic index for patients with parotid carcinoma - External validation using the nationwide 1985-1994 Dutch Head and Neck Oncology Cooperative Group database

    NARCIS (Netherlands)

    Vander Poorten, Vincent L. M.; Hart, Augustinus A. M.; van der Laan, Bernardus F. A. M.; Baatenburg de Jong, Robert J.; Manni, Johannes J.; Marres, Henri A. M.; Meeuwis, Cees A.; Lubsen, Herman; Terhaard, Chris H. J.; Balm, Alfonsus J. M.

    2003-01-01

    BACKGROUND. Validation of the prognostic indices for the recurrence-free interval of patients with parotid carcinoma, the development of which was described in a previous report, is needed to be confident of their generalizability and justified prospective use. METHODS. The Dutch Cooperative Group

  8. A clinical decision rule for the use of plain radiography in children after acute wrist injury: development and external validation of the Amsterdam Pediatric Wrist Rules

    Energy Technology Data Exchange (ETDEWEB)

    Slaar, Annelie; Maas, Mario; Rijn, Rick R. van [University of Amsterdam, Department of Radiology, Academic Medical Centre, Meibergdreef 9, 1105, AZ, Amsterdam (Netherlands); Walenkamp, Monique M.J.; Bentohami, Abdelali; Goslings, J.C. [University of Amsterdam, Trauma Unit, Department of Surgery, Academic Medical Centre, Amsterdam (Netherlands); Steyerberg, Ewout W. [Erasmus MC - University Medical Centre, Department of Public Health, Rotterdam (Netherlands); Jager, L.C. [University of Amsterdam, Emergency Department, Academic Medical Centre, Amsterdam (Netherlands); Sosef, Nico L. [Spaarne Hospital, Department of Surgery, Hoofddorp (Netherlands); Velde, Romuald van [Tergooi Hospitals, Department of Surgery, Hilversum (Netherlands); Ultee, Jan M. [Sint Lucas Andreas Hospital, Department of Surgery, Amsterdam (Netherlands); Schep, Niels W.L. [University of Amsterdam, Trauma Unit, Department of Surgery, Academic Medical Centre, Amsterdam (Netherlands); Maasstadziekenhuis Rotterdam, Department of Surgery, Rotterdam (Netherlands)

    2016-01-15

    In most hospitals, children with acute wrist trauma are routinely referred for radiography. To develop and validate a clinical decision rule to decide whether radiography in children with wrist trauma is required. We prospectively developed and validated a clinical decision rule in two study populations. All children who presented in the emergency department of four hospitals with pain following wrist trauma were included and evaluated for 18 clinical variables. The outcome was a wrist fracture diagnosed by plain radiography. Included in the study were 787 children. The prediction model consisted of six variables: age, swelling of the distal radius, visible deformation, distal radius tender to palpation, anatomical snuffbox tender to palpation, and painful or abnormal supination. The model showed an area under the receiver operator characteristics curve of 0.79 (95% CI: 0.76-0.83). The sensitivity and specificity were 95.9% and 37.3%, respectively. The use of this model would have resulted in a 22% absolute reduction of radiographic examinations. In a validation study, 7/170 fractures (4.1%, 95% CI: 1.7-8.3%) would have been missed using the decision model. The decision model may be a valuable tool to decide whether radiography in children after wrist trauma is required. (orig.)

  9. A clinical decision rule for the use of plain radiography in children after acute wrist injury: development and external validation of the Amsterdam Pediatric Wrist Rules

    International Nuclear Information System (INIS)

    Slaar, Annelie; Maas, Mario; Rijn, Rick R. van; Walenkamp, Monique M.J.; Bentohami, Abdelali; Goslings, J.C.; Steyerberg, Ewout W.; Jager, L.C.; Sosef, Nico L.; Velde, Romuald van; Ultee, Jan M.; Schep, Niels W.L.

    2016-01-01

    In most hospitals, children with acute wrist trauma are routinely referred for radiography. To develop and validate a clinical decision rule to decide whether radiography in children with wrist trauma is required. We prospectively developed and validated a clinical decision rule in two study populations. All children who presented in the emergency department of four hospitals with pain following wrist trauma were included and evaluated for 18 clinical variables. The outcome was a wrist fracture diagnosed by plain radiography. Included in the study were 787 children. The prediction model consisted of six variables: age, swelling of the distal radius, visible deformation, distal radius tender to palpation, anatomical snuffbox tender to palpation, and painful or abnormal supination. The model showed an area under the receiver operator characteristics curve of 0.79 (95% CI: 0.76-0.83). The sensitivity and specificity were 95.9% and 37.3%, respectively. The use of this model would have resulted in a 22% absolute reduction of radiographic examinations. In a validation study, 7/170 fractures (4.1%, 95% CI: 1.7-8.3%) would have been missed using the decision model. The decision model may be a valuable tool to decide whether radiography in children after wrist trauma is required. (orig.)

  10. Externality or sustainability economics?

    International Nuclear Information System (INIS)

    Bergh, Jeroen C.J.M. van den

    2010-01-01

    In an effort to develop 'sustainability economics' Baumgaertner and Quaas (2010) neglect the central concept of environmental economics-'environmental externality'. This note proposes a possible connection between the concepts of environmental externality and sustainability. In addition, attention is asked for other aspects of 'sustainability economics', namely the distinction weak/strong sustainability, spatial sustainability and sustainable trade, distinctive sustainability policy, and the ideas of early 'sustainability economists'. I argue that both sustainability and externalities reflect a systems perspective and propose that effective sustainability solutions require that more attention is given to system feedbacks, notably other-regarding preferences and social interactions, and energy and environmental rebound. The case of climate change and policy is used to illustrate particular statements. As a conclusion, a list of 20 insights and suggestions for research is offered. (author)

  11. Discrimination of Clover and Citrus Honeys from Egypt According to Floral Type Using Easily Assessable Physicochemical Parameters and Discriminant Analysis: An External Validation of the Chemometric Approach

    Directory of Open Access Journals (Sweden)

    Ioannis K. Karabagias

    2018-05-01

    Full Text Available Twenty-two honey samples, namely clover and citrus honeys, were collected from the greater Cairo area during the harvesting year 2014–2015. The main purpose of the present study was to characterize the aforementioned honey types and to investigate whether the use of easily assessable physicochemical parameters, including color attributes in combination with chemometrics, could differentiate honey floral origin. Parameters taken into account were: pH, electrical conductivity, ash, free acidity, lactonic acidity, total acidity, moisture content, total sugars (degrees Brix-°Bx, total dissolved solids and their ratio to total acidity, salinity, CIELAB color parameters, along with browning index values. Results showed that all honey samples analyzed met the European quality standards set for honey and had variations in the aforementioned physicochemical parameters depending on floral origin. Application of linear discriminant analysis showed that eight physicochemical parameters, including color, could classify Egyptian honeys according to floral origin (p < 0.05. Correct classification rate was 95.5% using the original method and 90.9% using the cross validation method. The discriminatory ability of the developed model was further validated using unknown honey samples. The overall correct classification rate was not affected. Specific physicochemical parameter analysis in combination with chemometrics has the potential to enhance the differences in floral honeys produced in a given geographical zone.

  12. Validity and reliability of isometric muscle strength measurements of hip abduction and abduction with external hip rotation in a bent-hip position using a handheld dynamometer with a belt.

    Science.gov (United States)

    Aramaki, Hidefumi; Katoh, Munenori; Hiiragi, Yukinobu; Kawasaki, Tsubasa; Kurihara, Tomohisa; Ohmi, Yorikatsu

    2016-07-01

    [Purpose] This study aimed to investigate the relatedness, reliability, and validity of isometric muscle strength measurements of hip abduction and abduction with an external hip rotation in a bent-hip position using a handheld dynamometer with a belt. [Subjects and Methods] Twenty healthy young adults, with a mean age of 21.5 ± 0.6 years were included. Isometric hip muscle strength in the subjects' right legs was measured under two posture positions using two devices: a handheld dynamometer with a belt and an isokinetic dynamometer. Reliability was evaluated using an intra-class correlation coefficient (ICC); relatedness and validity were evaluated using Pearson's product moment correlation coefficient. Differences in measurements of devices were assessed by two-way ANOVA. [Results] ICC (1, 1) was ≥0.9; significant positive correlations in measurements were found between the two devices under both conditions. No main effect was found between the measurement values. [Conclusion] Our findings revealed that there was relatedness, reliability, and validity of this method for isometric muscle strength measurements using a handheld dynamometer with a belt.

  13. External Validation of the ASTER GDEM2, GMTED2010 and CGIAR-CSI- SRTM v4.1 Free Access Digital Elevation Models (DEMs in Tunisia and Algeria

    Directory of Open Access Journals (Sweden)

    Djamel Athmania

    2014-05-01

    Full Text Available Digital Elevation Models (DEMs including Advanced Spaceborne Thermal Emission and Reflection Radiometer-Global Digital Elevation Model (ASTER GDEM, Shuttle Radar Topography Mission (SRTM, and Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010 are freely available for nearly the entire earth’s surface. DEMs that are usually subject to errors need to be evaluated using reference elevation data of higher accuracy. This work was performed to assess the vertical accuracy of the ASTER GDEM version 2, (ASTER GDEM2, the Consultative Group on International Agriculture Research-Consortium for Spatial Information (CGIAR-CSI SRTM version 4.1 (SRTM v4.1 and the systematic subsample GMTED2010, at their original spatial resolution, using Global Navigation Satellite Systems (GNSS validation points. Two test sites, the Anaguid Saharan platform in southern Tunisia and the Tebessa basin in north eastern Algeria, were chosen for accuracy assessment of the above mentioned DEMs, based on geostatistical and statistical measurements. Within the geostatistical approach, empirical variograms of each DEM were compared with those of the GPS validation points. Statistical measures were computed from the elevation differences between the DEM pixel value and the corresponding GPS point. For each DEM, a Root Mean Square Error (RMSE was determined for model validation. In addition, statistical tools such as frequency histograms and Q-Q plots were used to evaluate error distributions in each DEM. The results indicate that the vertical accuracy of SRTM model is much higher than ASTER GDEM2 and GMTED2010 for both sites. In Anaguid test site, the vertical accuracy of SRTM is estimated 3.6 m (in terms of RMSE 5.3 m and 4.5 m for the ASTERGDEM2 and GMTED2010 DEMs, respectively. In Tebessa test site, the overall vertical accuracy shows a RMSE of 9.8 m, 8.3 m and 9.6 m for ASTER GDEM 2, SRTM and GMTED2010 DEM, respectively. This work is the first study to report the

  14. External Validation and Recalibration of Risk Prediction Models for Acute Traumatic Brain Injury among Critically Ill Adult Patients in the United Kingdom.

    Science.gov (United States)

    Harrison, David A; Griggs, Kathryn A; Prabhu, Gita; Gomes, Manuel; Lecky, Fiona E; Hutchinson, Peter J A; Menon, David K; Rowan, Kathryn M

    2015-10-01

    This study validates risk prediction models for acute traumatic brain injury (TBI) in critical care units in the United Kingdom and recalibrates the models to this population. The Risk Adjustment In Neurocritical care (RAIN) Study was a prospective, observational cohort study in 67 adult critical care units. Adult patients admitted to critical care following acute TBI with a last pre-sedation Glasgow Coma Scale score of less than 15 were recruited. The primary outcomes were mortality and unfavorable outcome (death or severe disability, assessed using the Extended Glasgow Outcome Scale) at six months following TBI. Of 3626 critical care unit admissions, 2975 were analyzed. Following imputation of missing outcomes, mortality at six months was 25.7% and unfavorable outcome 57.4%. Ten risk prediction models were validated from Hukkelhoven and colleagues, the Medical Research Council (MRC) Corticosteroid Randomisation After Significant Head Injury (CRASH) Trial Collaborators, and the International Mission for Prognosis and Analysis of Clinical Trials in TBI (IMPACT) group. The model with the best discrimination was the IMPACT "Lab" model (C index, 0.779 for mortality and 0.713 for unfavorable outcome). This model was well calibrated for mortality at six months but substantially under-predicted the risk of unfavorable outcome. Recalibration of the models resulted in small improvements in discrimination and excellent calibration for all models. The risk prediction models demonstrated sufficient statistical performance to support their use in research and audit but fell below the level required to guide individual patient decision-making. The published models for unfavorable outcome at six months had poor calibration in the UK critical care setting and the models recalibrated to this setting should be used in future research.

  15. Prediction of high-grade vesicoureteral reflux after pediatric urinary tract infection: external validation study of procalcitonin-based decision rule.

    Directory of Open Access Journals (Sweden)

    Sandrine Leroy

    Full Text Available Predicting vesico-ureteral reflux (VUR ≥3 at the time of the first urinary tract infection (UTI would make it possible to restrict cystography to high-risk children. We previously derived the following clinical decision rule for that purpose: cystography should be performed in cases with ureteral dilation and a serum procalcitonin level ≥0.17 ng/mL, or without ureteral dilatation when the serum procalcitonin level ≥0.63 ng/mL. The rule yielded a 86% sensitivity with a 46% specificity. We aimed to test its reproducibility.A secondary analysis of prospective series of children with a first UTI. The rule was applied, and predictive ability was calculated.The study included 413 patients (157 boys, VUR ≥3 in 11% from eight centers in five countries. The rule offered a 46% specificity (95% CI, 41-52, not different from the one in the derivation study. However, the sensitivity significantly decreased to 64% (95%CI, 50-76, leading to a difference of 20% (95%CI, 17-36. In all, 16 (34% patients among the 47 with VUR ≥3 were misdiagnosed by the rule. This lack of reproducibility might result primarily from a difference between derivation and validation populations regarding inflammatory parameters (CRP, PCT; the validation set samples may have been collected earlier than for the derivation one.The rule built to predict VUR ≥3 had a stable specificity (ie. 46%, but a decreased sensitivity (ie. 64% because of the time variability of PCT measurement. Some refinement may be warranted.

  16. External validation of equations to estimate resting energy expenditure in 14952 adults with overweight and obesity and 1948 adults with normal weight from Italy.

    Science.gov (United States)

    Bedogni, Giorgio; Bertoli, Simona; Leone, Alessandro; De Amicis, Ramona; Lucchetti, Elisa; Agosti, Fiorenza; Marazzi, Nicoletta; Battezzati, Alberto; Sartorio, Alessandro

    2017-11-24

    We cross-validated 28 equations to estimate resting energy expenditure (REE) in a very large sample of adults with overweight or obesity. 14952 Caucasian men and women with overweight or obesity and 1498 with normal weight were studied. REE was measured using indirect calorimetry and estimated using two meta-regression equations and 26 other equations. The correct classification fraction (CCF) was defined as the fraction of subjects whose estimated REE was within 10% of measured REE. The highest CCF was 79%, 80%, 72%, 64%, and 63% in subjects with normal weight, overweight, class 1 obesity, class 2 obesity, and class 3 obesity, respectively. The Henry weight and height and Mifflin equations performed equally well with CCFs of 77% vs. 77% for subjects with normal weight, 80% vs. 80% for those with overweight, 72% vs. 72% for those with class 1 obesity, 64% vs. 63% for those with class 2 obesity, and 61% vs. 60% for those with class 3 obesity. The Sabounchi meta-regression equations offered an improvement over the above equations only for class 3 obesity (63%). The accuracy of REE equations decreases with increasing values of body mass index. The Henry weight & height and Mifflin equations are similarly accurate and the Sabounchi equations offer an improvement only in subjects with class 3 obesity. Copyright © 2017 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  17. External Validation of the Simple Clinical Score and the HOTEL Score, Two Scores for Predicting Short-Term Mortality after Admission to an Acute Medical Unit

    DEFF Research Database (Denmark)

    Stræde, Mia; Brabrand, Mikkel

    2014-01-01

    with the objective of validating the Simple Clinical Score (SCS) and the HOTEL score, two existing risk stratification systems that predict mortality for medical patients based solely on clinical information, but not only vital signs. METHODS: Pre-planned prospective observational cohort study. SETTING: Danish 460.......932 to 0.988) for 24-hours mortality and 0.826 (95% CI, 0.774-0.879) for 30-day mortality, and goodness-of-fit test, χ2 = 2.68 (10 degrees of freedom), P = 0.998 and χ2 = 4.00, P = 0.947, respectively. We included 1470 patients when calculating the HOTEL score. Discriminatory power (AUROC) was 0.931 (95......% CI, 0.901-0.962) for 24-hours mortality and goodness-of-fit test, χ2 = 5.56 (10 degrees of freedom), P = 0.234. CONCLUSION: We find that both the SCS and HOTEL scores showed an excellent to outstanding ability in identifying patients at high risk of dying with good or acceptable precision....

  18. Case-finding for common mental disorders of anxiety and depression in primary care: an external validation of routinely collected data.

    Science.gov (United States)

    John, Ann; McGregor, Joanne; Fone, David; Dunstan, Frank; Cornish, Rosie; Lyons, Ronan A; Lloyd, Keith R

    2016-03-15

    The robustness of epidemiological research using routinely collected primary care electronic data to support policy and practice for common mental disorders (CMD) anxiety and depression would be greatly enhanced by appropriate validation of diagnostic codes and algorithms for data extraction. We aimed to create a robust research platform for CMD using population-based, routinely collected primary care electronic data. We developed a set of Read code lists (diagnosis, symptoms, treatments) for the identification of anxiety and depression in the General Practice Database (GPD) within the Secure Anonymised Information Linkage Databank at Swansea University, and assessed 12 algorithms for Read codes to define cases according to various criteria. Annual incidence rates were calculated per 1000 person years at risk (PYAR) to assess recording practice for these CMD between January 1(st) 2000 and December 31(st) 2009. We anonymously linked the 2799 MHI-5 Caerphilly Health and Social Needs Survey (CHSNS) respondents aged 18 to 74 years to their routinely collected GP data in SAIL. We estimated the sensitivity, specificity and positive predictive value of the various algorithms using the MHI-5 as the gold standard. The incidence of combined depression/anxiety diagnoses remained stable over the ten-year period in a population of over 500,000 but symptoms increased from 6.5 to 20.7 per 1000 PYAR. A 'historical' GP diagnosis for depression/anxiety currently treated plus a current diagnosis (treated or untreated) resulted in a specificity of 0.96, sensitivity 0.29 and PPV 0.76. Adding current symptom codes improved sensitivity (0.32) with a marginal effect on specificity (0.95) and PPV (0.74). We have developed an algorithm with a high specificity and PPV of detecting cases of anxiety and depression from routine GP data that incorporates symptom codes to reflect GP coding behaviour. We have demonstrated that using diagnosis and current treatment alone to identify cases for

  19. External validation of a multivariable claims-based rule for predicting in-hospital mortality and 30-day post-pulmonary embolism complications

    Directory of Open Access Journals (Sweden)

    Craig I. Coleman

    2016-10-01

    Full Text Available Abstract Background Low-risk pulmonary embolism (PE patients may be candidates for outpatient treatment or abbreviated hospital stay. There is a need for a claims-based prediction rule that payers/hospitals can use to risk stratify PE patients. We sought to validate the In-hospital Mortality for PulmonAry embolism using Claims daTa (IMPACT prediction rule for in-hospital and 30-day outcomes. Methods We used the Optum Research Database from 1/2008-3/2015 and included adults hospitalized for PE (415.1x in the primary position or secondary position when accompanied by a primary code for a PE complication and having continuous medical and prescription coverage for ≥6-months prior and 3-months post-inclusion or until death. In-hospital and 30-day mortality and 30-day complications (recurrent venous thromboembolism, rehospitalization or death were assessed and prognostic accuracies of IMPACT with 95 % confidence intervals (CIs were calculated. Results In total, 47,531 PE patients were included. In-hospital and 30-day mortality occurred in 7.9 and 9.4 % of patients and 20.8 % experienced any complication within 30-days. Of the 19.5 % of patients classified as low-risk by IMPACT, 2.0 % died in-hospital, resulting in a sensitivity and specificity of 95.2 % (95 % CI, 94.4–95.8 and 20.7 % (95 % CI, 20.4–21.1. Only 1 additional low-risk patient died within 30-days of admission and 12.2 % experienced a complication, translating into a sensitivity and specificity of 95.9 % (95 % CI, 95.3–96.5 and 21.1 % (95 % CI, 20.7–21.5 for mortality and 88.5 % (95 % CI, 87.9–89.2 and 21.6 % (95 % CI, 21.2–22.0 for any complication. Conclusion IMPACT had acceptable sensitivity for predicting in-hospital and 30-day mortality or complications and may be valuable for retrospective risk stratification of PE patients.

  20. External validation of a multivariable claims-based rule for predicting in-hospital mortality and 30-day post-pulmonary embolism complications.

    Science.gov (United States)

    Coleman, Craig I; Peacock, W Frank; Fermann, Gregory J; Crivera, Concetta; Weeda, Erin R; Hull, Michael; DuCharme, Mary; Becker, Laura; Schein, Jeff R

    2016-10-22

    Low-risk pulmonary embolism (PE) patients may be candidates for outpatient treatment or abbreviated hospital stay. There is a need for a claims-based prediction rule that payers/hospitals can use to risk stratify PE patients. We sought to validate the In-hospital Mortality for PulmonAry embolism using Claims daTa (IMPACT) prediction rule for in-hospital and 30-day outcomes. We used the Optum Research Database from 1/2008-3/2015 and included adults hospitalized for PE (415.1x in the primary position or secondary position when accompanied by a primary code for a PE complication) and having continuous medical and prescription coverage for ≥6-months prior and 3-months post-inclusion or until death. In-hospital and 30-day mortality and 30-day complications (recurrent venous thromboembolism, rehospitalization or death) were assessed and prognostic accuracies of IMPACT with 95 % confidence intervals (CIs) were calculated. In total, 47,531 PE patients were included. In-hospital and 30-day mortality occurred in 7.9 and 9.4 % of patients and 20.8 % experienced any complication within 30-days. Of the 19.5 % of patients classified as low-risk by IMPACT, 2.0 % died in-hospital, resulting in a sensitivity and specificity of 95.2 % (95 % CI, 94.4-95.8) and 20.7 % (95 % CI, 20.4-21.1). Only 1 additional low-risk patient died within 30-days of admission and 12.2 % experienced a complication, translating into a sensitivity and specificity of 95.9 % (95 % CI, 95.3-96.5) and 21.1 % (95 % CI, 20.7-21.5) for mortality and 88.5 % (95 % CI, 87.9-89.2) and 21.6 % (95 % CI, 21.2-22.0) for any complication. IMPACT had acceptable sensitivity for predicting in-hospital and 30-day mortality or complications and may be valuable for retrospective risk stratification of PE patients.

  1. Radiation effects on relativistic electrons in strong external fields

    International Nuclear Information System (INIS)

    Iqbal, Khalid

    2013-01-01

    The effects of radiation of high energy electron beams are a major issue in almost all types of charged particle accelerators. The objective of this thesis is both the analytical and numerical study of radiation effects. Due to its many applications the study of the self force has become a very active and productive field of research. The main part of this thesis is devoted to the study of radiation effects in laser-based plasma accelerators. Analytical models predict the existence of radiation effects. The investigation of radiation reaction show that in laser-based plasma accelerators, the self force effects lower the energy gain and emittance for moderate energies electron beams and increase the relative energy spread. However, for relatively high energy electron beams, the self radiation and retardation (radiation effects of one electron on the other electron of the system) effects increase the transverse emittance of the beam. The energy gain decreases to even lower value and relative energy spread increases to even higher value due to high radiation losses. The second part of this thesis investigates with radiation reaction in focused laser beams. Radiation effects are very weak even for high energy electrons. The radiation-free acceleration and the simple practical setup make direct acceleration in a focused laser beam very attractive. The results presented in this thesis can be helpful for the optimization of future electron acceleration experiments, in particular in the case of laser-plasma accelerators.

  2. EXTERNAL EVIDENCE IN THE VALIDATION OF MENTALISTIC ...

    African Journals Online (AJOL)

    rical nature of his mentalistic theories, grammatical as well as general linguistic. The obvious way .... process of language acquisition or growth the cognitive system character- ized by the general ... then, abstract in a dual sense: in the sense of ...

  3. PHOSPHORUS SORPTION ISOTHERMS AND EXTERNAL ...

    African Journals Online (AJOL)

    ACSS

    Zhang et al., 2005). For instance, in strongly acidic soils with pH<5.5 and high P sorbing soils, application of rock phosphate is more effective and cheaper than using TSP (Bationo et al., 2011). Moreover, it enables determination of the external P.

  4. High Intensity Compton Scattering in a strong plane wave field of general form

    International Nuclear Information System (INIS)

    Hartin, A.; Moortgat-Pick, G.; Hamburg Univ.

    2011-06-01

    Photon emission by an electron embedded in a strong external field of general form is studied theoretically. The external field considered is a plane wave electromagnetic field of any number of components, period and polarisation. Exact, Volkov solutions of the Dirac equation with the 4-potential of the general external field are obtained. The photon emission is considered in the usual perturbation theory using the Volkov solutions to represent the electron. An expression for the transition probability of this process is obtained after the usual spin and polarisation sums, trace calculation and phase space integration. The final transition probability in the general case contains a single sum over contributions from external field photons, an integration over one of the phase space components and the Fourier transforms of the Volkov phases. The validity of the general expression is established by considering specific external fields. Known specific analytic forms of the transition probability are obtained after substitution of the 4-potential for a circularly polarised and constant crossed external field. As an example usage of the general result for the transition probability, the case of two circularly polarised external fields separated by a phase difference is studied both analytically and numerically. (orig.)

  5. High Intensity Compton Scattering in a strong plane wave field of general form

    Energy Technology Data Exchange (ETDEWEB)

    Hartin, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Moortgat-Pick, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2011-06-15

    Photon emission by an electron embedded in a strong external field of general form is studied theoretically. The external field considered is a plane wave electromagnetic field of any number of components, period and polarisation. Exact, Volkov solutions of the Dirac equation with the 4-potential of the general external field are obtained. The photon emission is considered in the usual perturbation theory using the Volkov solutions to represent the electron. An expression for the transition probability of this process is obtained after the usual spin and polarisation sums, trace calculation and phase space integration. The final transition probability in the general case contains a single sum over contributions from external field photons, an integration over one of the phase space components and the Fourier transforms of the Volkov phases. The validity of the general expression is established by considering specific external fields. Known specific analytic forms of the transition probability are obtained after substitution of the 4-potential for a circularly polarised and constant crossed external field. As an example usage of the general result for the transition probability, the case of two circularly polarised external fields separated by a phase difference is studied both analytically and numerically. (orig.)

  6. Extracting the emitter orientation in organic light-emitting diodes from external quantum efficiency measurements

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Tobias D., E-mail: Tobias.Schmidt@physik.uni-augsburg.de; Reichardt, Lukas J.; Wehrmeister, Sebastian; Scholz, Bert J.; Mayr, Christian; Brütting, Wolfgang, E-mail: Wolfgang.Bruetting@physik.uni-augsburg.de [Institute of Physics, University of Augsburg, 86135 Augsburg (Germany); Rausch, Andreas F.; Wehlus, Thomas; Reusch, Thilo C. G. [OSRAM OLED GmbH, Wernerwerkstrasse 2, 93049 Regensburg (Germany); Ciarnáin, Rossá Mac; Danz, Norbert [Fraunhofer Institute for Applied Optics and Precision Engineering, 07745 Jena (Germany)

    2014-07-28

    Emitter orientation will play a major role in future applications of organic light-emitting diodes due to its strong impact on the efficiency of the devices. Up to now, determining the orientation of transition dipole moments required elaborate angular-dependent measurements of the light emission pattern. In this paper, we present a simplified and straightforward method to extract the emitter orientation from external quantum efficiency measurements. We demonstrate the validity of the method on three different dye-doped emitting systems.

  7. Strong cosmic censorship and the strong curvature singularities

    International Nuclear Information System (INIS)

    Krolak, A.

    1987-01-01

    Conditions are given under which any asymptotically simple and empty space-time that has a partial Cauchy surface with an asymptotically simple past is globally hyperbolic. It is shown that this result suggests that the Cauchy horizons of the type occurring in Reissner--Nordstroem and Kerr space-times are unstable. This in turn gives support for the validity of the strong cosmic censorship hypothesis

  8. Rydberg atoms in strong fields

    International Nuclear Information System (INIS)

    Kleppner, D.; Tsimmerman, M.

    1985-01-01

    Experimental and theoretical achievements in studying Rydberg atoms in external fields are considered. Only static (or quasistatic) fields and ''one-electron'' atoms, i.e. atoms that are well described by one-electron states, are discussed. Mainly behaviour of alkali metal atoms in electric field is considered. The state of theoretical investigations for hydrogen atom in magnetic field is described, but experimental data for atoms of alkali metals are presented as an illustration. Results of the latest experimental and theoretical investigations into the structure of Rydberg atoms in strong fields are presented

  9. Modified multiple time scale method for solving strongly nonlinear damped forced vibration systems

    Science.gov (United States)

    Razzak, M. A.; Alam, M. Z.; Sharif, M. N.

    2018-03-01

    In this paper, modified multiple time scale (MTS) method is employed to solve strongly nonlinear forced vibration systems. The first-order approximation is only considered in order to avoid complexicity. The formulations and the determination of the solution procedure are very easy and straightforward. The classical multiple time scale (MS) and multiple scales Lindstedt-Poincare method (MSLP) do not give desire result for the strongly damped forced vibration systems with strong damping effects. The main aim of this paper is to remove these limitations. Two examples are considered to illustrate the effectiveness and convenience of the present procedure. The approximate external frequencies and the corresponding approximate solutions are determined by the present method. The results give good coincidence with corresponding numerical solution (considered to be exact) and also provide better result than other existing results. For weak nonlinearities with weak damping effect, the absolute relative error measures (first-order approximate external frequency) in this paper is only 0.07% when amplitude A = 1.5 , while the relative error gives MSLP method is surprisingly 28.81%. Furthermore, for strong nonlinearities with strong damping effect, the absolute relative error found in this article is only 0.02%, whereas the relative error obtained by MSLP method is 24.18%. Therefore, the present method is not only valid for weakly nonlinear damped forced systems, but also gives better result for strongly nonlinear systems with both small and strong damping effect.

  10. Delirium risk stratification in consecutive unselected admissions to acute medicine: validation of a susceptibility score based on factors identified externally in pooled data for use at entry to the acute care pathway.

    Science.gov (United States)

    Pendlebury, Sarah T; Lovett, Nicola G; Smith, Sarah C; Wharton, Rose; Rothwell, Peter M

    2017-03-01

    recognition of prevalent delirium and prediction of incident delirium may be difficult at first assessment. We therefore aimed to validate a pragmatic delirium susceptibility (for any, prevalent and incident delirium) score for use in front-line clinical practice in a consecutive cohort of older acute medicine patients. consecutive patients aged ≥65 years over two 8-week periods (2010-12) were screened prospectively for delirium using the Confusion Assessment Method (CAM), and delirium was diagnosed using the DSM IV criteria. The delirium susceptibility score was the sum of weighted risk factors derived using pooled data from UK-NICE guidelines: age >80 = 2, cognitive impairment (cognitive score below cut-off/dementia) = 2, severe illness (systemic inflammatory response syndrome) = 1, infection = 1, visual impairment = 1. Score reliability was determined by the area under the receiver operating curve (AUC). among 308 consecutive patients aged ≥65 years (mean age/SD = 81/8 years, 164 (54%) female), AUC was 0.78 (95% CI 0.71-0.84) for any delirium; 0.71 (0.64-0.79), for prevalent delirium; 0.81 (0.70-0.92), for incident delirium; odds ratios (ORs) for risk score 5-7 versus delirium, 8.1 (2.2-29.7), P = 0.002 for prevalent delirium, and 25.0 (3.0-208.9) P = 0.003 for incident delirium, with corresponding relative risks of 5.4, 4.7 and 13. Higher risk scores were associated with frailty markers, increased care needs and poor outcomes. the externally derived delirium susceptibility score reliably identified prevalent and incident delirium using clinical data routinely available at initial patient assessment and might therefore aid recognition of vulnerability in acute medical admissions early in the acute care pathway. © The Author 2016. Published by Oxford University Press on behalf of the British Geriatrics Society.

  11. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1979-01-01

    The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)

  12. Regulating multiple externalities

    DEFF Research Database (Denmark)

    Waldo, Staffan; Jensen, Frank; Nielsen, Max

    2016-01-01

    Open access is a well-known externality problem in fisheries causing excess capacity and overfishing. Due to global warming, externality problems from CO2 emissions have gained increased interest. With two externality problems, a first-best optimum can be achieved by using two regulatory instrume......Open access is a well-known externality problem in fisheries causing excess capacity and overfishing. Due to global warming, externality problems from CO2 emissions have gained increased interest. With two externality problems, a first-best optimum can be achieved by using two regulatory...

  13. ExternE National Implementation Finland

    Energy Technology Data Exchange (ETDEWEB)

    Pingoud, K; Maelkki, H; Wihersaari, M; Pirilae, P [VTT Energy, Espoo (Finland); Hongisto, M [Imatran Voima Oy, Vantaa (Finland); Siitonen, S [Ekono Energy Ltd, Espoo (Finland); Johansson, M [Finnish Environment Institute, Helsinki (Finland)

    1999-07-01

    ExternE National Implementation is a continuation of the ExternE Project, funded in part by the European Commission's Joule III Programme. This study is the result of the ExternE National Implementation Project for Finland. Three fuel cycles were selected for the Finnish study: coal, peat and wood-derived biomass, which together are responsible for about 40% of total electricity generation in Finland and about 75% of the non-nuclear fuel based generation. The estimated external costs or damages were dominated by the global warming (GW) impacts in the coal and peat fuel cycles, but knowledge of the true GW impacts is still uncertain. From among other impacts that were valued in monetary terms the human health damages due to airborne emissions dominated in all the three fuel cycles. Monetary valuation for ecosystem impacts is not possible using the ExternE methodology at present. The Meri-Pori power station representing the coal fuel cycle is one of the world's cleanest and most efficient coal-fired power plants with a condensing turbine. The coal is imported mainly from Poland. The estimated health damages were about 4 mECU/kWh, crop damages an order of magnitude lower and damages caused to building materials two orders of magnitude lower. The power stations of the peat and biomass fuel cycles are of CHP type, generating electricity and heat for the district heating systems of two cities. Their fuels are of domestic origin. The estimated health damages allocated to electricity generation were about 5 and 6 mECU/kWh, respectively. The estimates were case-specific and thus an generalisation of the results to the whole electricity generation in Finland is unrealistic. Despite the uncertainties and limitations of the methodology, it is a promising tool in the comparison of similar kinds of fuel cycles, new power plants and pollution abatement technologies and different plant locations with each other. (orig.)

  14. ExternE National Implementation Finland

    International Nuclear Information System (INIS)

    Pingoud, K.; Maelkki, H.; Wihersaari, M.; Pirilae, P.; Hongisto, M.; Siitonen, S.; Johansson, M.

    1999-01-01

    ExternE National Implementation is a continuation of the ExternE Project, funded in part by the European Commission's Joule III Programme. This study is the result of the ExternE National Implementation Project for Finland. Three fuel cycles were selected for the Finnish study: coal, peat and wood-derived biomass, which together are responsible for about 40% of total electricity generation in Finland and about 75% of the non-nuclear fuel based generation. The estimated external costs or damages were dominated by the global warming (GW) impacts in the coal and peat fuel cycles, but knowledge of the true GW impacts is still uncertain. From among other impacts that were valued in monetary terms the human health damages due to airborne emissions dominated in all the three fuel cycles. Monetary valuation for ecosystem impacts is not possible using the ExternE methodology at present. The Meri-Pori power station representing the coal fuel cycle is one of the world's cleanest and most efficient coal-fired power plants with a condensing turbine. The coal is imported mainly from Poland. The estimated health damages were about 4 mECU/kWh, crop damages an order of magnitude lower and damages caused to building materials two orders of magnitude lower. The power stations of the peat and biomass fuel cycles are of CHP type, generating electricity and heat for the district heating systems of two cities. Their fuels are of domestic origin. The estimated health damages allocated to electricity generation were about 5 and 6 mECU/kWh, respectively. The estimates were case-specific and thus an generalisation of the results to the whole electricity generation in Finland is unrealistic. Despite the uncertainties and limitations of the methodology, it is a promising tool in the comparison of similar kinds of fuel cycles, new power plants and pollution abatement technologies and different plant locations with each other. (orig.)

  15. ExternE National Implementation Finland

    Energy Technology Data Exchange (ETDEWEB)

    Pingoud, K.; Maelkki, H.; Wihersaari, M.; Pirilae, P. [VTT Energy, Espoo (Finland); Hongisto, M. [Imatran Voima Oy, Vantaa (Finland); Siitonen, S. [Ekono Energy Ltd, Espoo (Finland); Johansson, M. [Finnish Environment Institute, Helsinki (Finland)

    1999-07-01

    ExternE National Implementation is a continuation of the ExternE Project, funded in part by the European Commission's Joule III Programme. This study is the result of the ExternE National Implementation Project for Finland. Three fuel cycles were selected for the Finnish study: coal, peat and wood-derived biomass, which together are responsible for about 40% of total electricity generation in Finland and about 75% of the non-nuclear fuel based generation. The estimated external costs or damages were dominated by the global warming (GW) impacts in the coal and peat fuel cycles, but knowledge of the true GW impacts is still uncertain. From among other impacts that were valued in monetary terms the human health damages due to airborne emissions dominated in all the three fuel cycles. Monetary valuation for ecosystem impacts is not possible using the ExternE methodology at present. The Meri-Pori power station representing the coal fuel cycle is one of the world's cleanest and most efficient coal-fired power plants with a condensing turbine. The coal is imported mainly from Poland. The estimated health damages were about 4 mECU/kWh, crop damages an order of magnitude lower and damages caused to building materials two orders of magnitude lower. The power stations of the peat and biomass fuel cycles are of CHP type, generating electricity and heat for the district heating systems of two cities. Their fuels are of domestic origin. The estimated health damages allocated to electricity generation were about 5 and 6 mECU/kWh, respectively. The estimates were case-specific and thus an generalisation of the results to the whole electricity generation in Finland is unrealistic. Despite the uncertainties and limitations of the methodology, it is a promising tool in the comparison of similar kinds of fuel cycles, new power plants and pollution abatement technologies and different plant locations with each other. (orig.)

  16. Intermittency in Hall-magnetohydrodynamics with a strong guide field

    International Nuclear Information System (INIS)

    Rodriguez Imazio, P.; Martin, L. N.; Dmitruk, P.; Mininni, P. D.

    2013-01-01

    We present a detailed study of intermittency in the velocity and magnetic field fluctuations of compressible Hall-magnetohydrodynamic turbulence with an external guide field. To solve the equations numerically, a reduced model valid when a strong guide field is present is used. Different values for the ion skin depth are considered in the simulations. The resulting data are analyzed computing field increments in several directions perpendicular to the guide field, and building structure functions and probability density functions. In the magnetohydrodynamic limit, we recover the usual results with the magnetic field being more intermittent than the velocity field. In the presence of the Hall effect, field fluctuations at scales smaller than the ion skin depth show a substantial decrease in the level of intermittency, with close to monofractal scaling

  17. External Otitis (Swimmer's Ear)

    Science.gov (United States)

    ... otitis. Fungal external otitis (otomycosis), typically caused by Aspergillus niger or Candida albicans, is less common. Boils are ... in the ear. Fungal external otitis caused by Aspergillus niger usually causes grayish black or yellow dots (called ...

  18. ExternE: Externalities of energy Vol. 2. Methodology

    International Nuclear Information System (INIS)

    Berry, J.; Holland, M.; Watkiss, P.

    1995-01-01

    This report describes the methodology used by the ExternE Project of the European Commission (DGXII) JOULE Programme for assessment of the external costs of energy. It is one of a series of reports describing analysis of nuclear, fossil and renewable fuel cycles for assessment of the externalities associated with electricity generation. Part I of the report deals with analysis of impacts, and Part II with the economic valuation of those impacts. Analysis is conducted on a marginal basis, to allow the effect of an incremental investment in a given technology to be quantified. Attention has been paid to the specificity of results with respect to the location of fuel cycle activities, the precise technologies used, and the type and source of fuel. The main advantages of this detailed approach are as follows: It takes full and proper account of the variability of impacts that might result from different power projects; It is more transparent than analysis based on hypothetically 'representative' cases for each of the different fuel cycles; It provides a framework for consistent comparison between fuel cycles. A wide variety of impacts have been considered. These include the effects of air pollution on the natural and human environment, consequences of accidents in the workplace, impacts of noise and visual intrusion on amenity, and the effects of climate change arising from the release of greenhouse gases. Wherever possible we have used the 'impact pathway' or 'damage function' approach to follow the analysis from identification of burdens (e.g. emissions) through to impact assessment and then valuation in monetary terms. This has required a detailed knowledge of the technologies involved, pollutant dispersion, analysis of effects on human and environmental health, and economics. In view of this the project brought together a multi-disciplinary team with experts from many European countries and the USA. The spatial and temporal ranges considered in the analysis are

  19. ASH External Web Portal (External Portal) -

    Data.gov (United States)

    Department of Transportation — The ASH External Web Portal is a web-based portal that provides single sign-on functionality, making the web portal a single location from which to be authenticated...

  20. Abortion: Strong's counterexamples fail

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2009-01-01

    This paper shows that the counterexamples proposed by Strong in 2008 in the Journal of Medical Ethics to Marquis's argument against abortion fail. Strong's basic idea is that there are cases--for example, terminally ill patients--where killing an adult human being is prima facie seriously morally...

  1. Strong Langmuir turbulence

    International Nuclear Information System (INIS)

    Goldman, M.V.

    1984-01-01

    After a brief discussion of beam-excited Langmuir turbulence in the solar wind, we explain the criteria for wave-particle, three-wave and strong turbulence interactions. We then present the results of a numerical integration of the Zakharov equations, which describe the strong turbulence saturation of a weak (low-density) high energy, bump-on-tail beam instability. (author)

  2. TIMES-SS - A promising tool for the assessment of skin sensitization hazard. A characterization with respect to the OECD validation principles for (Q)SARs and an external evaluation for predictivity

    DEFF Research Database (Denmark)

    Patlewicz, Grace; Dimitrov, Sabcho D.; Low, Lawrence K.

    2007-01-01

    principles are met and in particular the results from an external evaluation exercise that was recently carried out. As part of this exercise, data were generated for 40 new chemicals in the murine local lymph node assay (LLNA) and then compared with predictions made by TIMES-SS. The results were promising...

  3. Unification of electromagnetic, strong and weak interaction

    International Nuclear Information System (INIS)

    Duong Van Phi; Duong Anh Duc

    1993-09-01

    The Unification of Electromagnetic, Strong and Weak Interactions is realized in the framework of the Quantum Field Theory, established in an 8-dimensional Unified Space. Two fundamental, spinor and vector field equations are considered. The first of the matter particles and the second is of the gauge particles. Interaction Lagrangians are formed from the external and internal currents and the external and internal vector field operators. Generators of the local gauge transformations are the combinations of the matrices of the first field equation. (author). 15 refs

  4. ExternE: Externalities of energy Vol. 1. Summary

    International Nuclear Information System (INIS)

    Holland, M.; Berry, J.

    1995-01-01

    There is a growing requirement for policy analysts to take account of the environment in their decision making and to undertake the specified cost-benefit analysis. Within the European Union this is reflected in the 5th Environmental Action Programme, and the Commission's White Paper entitled 'Growth, competitiveness, employment and the ways forward to the 21st century'. This has led to a need for evaluation of environmental externalities. The ExternE Project commenced in 1991 as the European part of a collaborative study between the European Commission and the US Department of Energy. It aims to be the first systematic approach to the evaluation of external costs of a wide range of different fuel cycles. The project will result in an operational accounting framework for the quantification and monetarisation of priority environmental and other externalities. This framework will allow the calculation of the marginal external costs and benefits for specific power plants, at specific sites using specified technologies. There are three major phases in the project. Phase 1 was undertaken in collaboration with the US Department of Energy. In this phase the teams jointly developed the conceptual approach and methodology and shared scientific information for application to a number of fuel cycles. On the European side work concentrated on the nuclear and coal fuel cycles which together were expected to raise many of the fundamental issues in fuel cycle analysis. The project is currently nearing completion of Phase 2. During this phase the methodology has been applied to a wide range of different fossil, nuclear and renewable fuel cycles for power generation and energy conservation options. Also a series of National Implementation Programmes is underway in which the methodology and accounting framework are being applied to reference sites throughout Europe. In addition the general methodology is being extended to address the evaluation of externalities associated with

  5. Externalities of fuel cycles 'ExternE' project. Summary report

    International Nuclear Information System (INIS)

    Holland, M.; Berry, J.

    1994-01-01

    There is a growing requirement for policy analysts to take account of the environment in their decision making and to undertake the specified cost-benefit analysis. Within the European Union this is reflected in the 5th Environmental Action Programme, and the Commission's White Paper entitled 'Growth, competitiveness, employment and the ways forward to the 21st century'. This has led to a need for evaluation of environmental externalities. The ExternE Project commenced in 1991 as the European part of a collaborative study between the European Commission and the US Department of Energy. It aims to be the first systematic approach to the evaluation of external costs of a wide range of different fuel cycles. The project will result in an operational accounting framework for the quantification and monetarisation of priority environmental and other externalities. This framework will allow the calculation of the marginal external costs and benefits for specific power plants, at specific sites using specified technologies. There are three major phases in the project. Phase I was undertaken in collaboration with the US Department of Energy. In this phase the teams jointly developed the conceptual approach and methodology and shared scientific information for application to a number of fuel cycles. On the European side work concentrated on the nuclear and coal fuel cycles which together were expected to raise many of the fundamental issues in fuel cycle analysis. The project is currently nearing completion of Phase 2. During this phase the methodology has been applied to a wide range of different fossil, nuclear and renewable fuel cycles for power generation and energy conservation options. Also a series of National Implementation Programmes are underway in which the methodology and accounting framework are being applied to reference sites throughout Europe. In addition the general methodology is being extended to address the evaluation of externalities associated with

  6. Strong intrinsic motivation

    OpenAIRE

    Dessi, Roberta; Rustichini, Aldo

    2015-01-01

    A large literature in psychology, and more recently in economics, has argued that monetary rewards can reduce intrinsic motivation. We investigate whether the negative impact persists when intrinsic motivation is strong, and test this hypothesis experimentally focusing on the motivation to undertake interesting and challenging tasks, informative about individual ability. We find that this type of task can generate strong intrinsic motivation, that is impervious to the effect of monetary incen...

  7. Bitcoin Meets Strong Consistency

    OpenAIRE

    Decker, Christian; Seidel, Jochen; Wattenhofer, Roger

    2014-01-01

    The Bitcoin system only provides eventual consistency. For everyday life, the time to confirm a Bitcoin transaction is prohibitively slow. In this paper we propose a new system, built on the Bitcoin blockchain, which enables strong consistency. Our system, PeerCensus, acts as a certification authority, manages peer identities in a peer-to-peer network, and ultimately enhances Bitcoin and similar systems with strong consistency. Our extensive analysis shows that PeerCensus is in a secure state...

  8. Strong gravity and supersymmetry

    International Nuclear Information System (INIS)

    Chamseddine, Ali H.; Salam, A.; Strathdee, J.

    1977-11-01

    A supersymmetric theory is constructed for a strong f plus a weak g graviton, together with their accompanying massive gravitinos, by gaugin the gradel 0Sp(2,2,1)x 0Sp(2,2,1) structure. The mixing term between f and g fields, which makes the strong graviton massive, can be introduced through a spontaneous symmetry-breaking mechanism implemented in this note by constructing a non-linear realization of the symmetry group

  9. External radiation surveillance

    International Nuclear Information System (INIS)

    Antonio, E.J.

    1995-01-01

    This section of the 1994 Hanford Site Environmental Report describes how external radiation was measured, how surveys were performed, and the results of these measurements and surveys. External radiation exposure rates were measured at locations on and off the Hanford Site using thermoluminescent dosimeters (TLD). External radiation and contamination surveys were also performed with portable radiation survey instruments at locations on and around the Hanford Site

  10. External radiation surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, E.J.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report describes how external radiation was measured, how surveys were performed, and the results of these measurements and surveys. External radiation exposure rates were measured at locations on and off the Hanford Site using thermoluminescent dosimeters (TLD). External radiation and contamination surveys were also performed with portable radiation survey instruments at locations on and around the Hanford Site.

  11. External noise distinguishes attention mechanisms.

    Science.gov (United States)

    Lu, Z L; Dosher, B A

    1998-05-01

    We developed and tested a powerful method for identifying and characterizing the effect of attention on performance in visual tasks as due to signal enhancement, distractor exclusion, or internal noise suppression. Based on a noisy Perceptual Template Model (PTM) of a human observer, the method adds increasing amounts of external noise (white gaussian random noise) to the visual stimulus and observes the effect on performance of a perceptual task for attended and unattended stimuli. The three mechanisms of attention yield three "signature" patterns of performance. The general framework for characterizing the mechanisms of attention is used here to investigate the attentional mechanisms in a concurrent location-cued orientation discrimination task. Test stimuli--Gabor patches tilted slightly to the right or left--always appeared on both the left and the right of fixation, and varied independently. Observers were cued on each trial to attend to the left, the right, or evenly to both stimuli, and decide the direction of tilt of both test stimuli. For eight levels of added external noise and three attention conditions (attended, unattended, and equal), subjects' contrast threshold levels were determined. At low levels of external noise, attention affected threshold contrast: threshold contrasts for non-attended stimuli were systematically higher than for equal attention stimuli, which were, in turn, higher than for attended stimuli. Specifically, when the rms contrast of the external noise is below 10%, there is a consistent 17% elevation of contrast threshold from attended to unattended condition across all three subjects. For higher levels of external noise, attention conditions did not affect threshold contrast values at all. These strong results are characteristic of a signal enhancement, or equivalently, an internal additive noise reduction mechanism of attention.

  12. ExternE: Externalities of energy Vol. 5. Nuclear

    International Nuclear Information System (INIS)

    Dreicer, M.; Tort, V.; Manen, P.

    1995-01-01

    Since the early 1970s, there has been increased interest in the environmental impacts that are caused by the generation of electricity. The comparative risk assessment studies at that time used mainly deaths and injuries as impact indicators. By the end of the 1980s studies changed to the assessment of the costs imposed on society and the environment that were not included in the market price of the energy produced, the so-called external costs. The preliminary studies that were published set the conceptual basis, grounded in neo-classical economics, for the valuation of the health and environmental impacts that could be assessed. As a consequence of the many questions raised by the methodologies employed by these early studies, Directorate General XII (DG XII) of the Commission of the European Communities established a collaborative research programme with the United States Department of Energy to identify an appropriate methodology for this type of work. Following the completion of this collaboration, the DG XII programme has continued as the ExternE project. The main objective of the work carried out at CEPN was to develop an impact pathway methodology for the nuclear fuel cycle that would be consistent with the methodologies developed for other fuel cycles, without loosing the nuclear-specific techniques required for a proper evaluation. In this way, comparisons between the different fuel cycles would be possible. This report presents the methodology and demonstration of the results in the context of the French nuclear fuel cycle. The United States team at Oak Ridge National Laboratory has previously issued a draft report on the results of their assessment. The French fuel cycle was broken down into 8 separate stages. Reference sites and 1990s technology were chosen to represent the total nuclear fuel cycle, as it exists today. In addition, the transportation of material between the sites was considered. The facilities are assessed for routine operation, except

  13. External quality control of Pléiades orthoimagery – Part II: Geometric testing and validation of a Pléiades-1B orthoproduct covering Maussane test site

    OpenAIRE

    GRAZZINI Jacopo; AASTRAND Paer

    2013-01-01

    The goal of the current report is to provide with a final statement on the geometric capabilities of Pléiades sensors through the Quality Control (QC) of Pléiades-1B orthocorrected imagery following the recent validation of Pléiades-1A. Namely, the validation process aims at measuring the influence of different factors on the geometric accuracy of Pléiades-1B orthoimagery. For that purpose, a light benchmarking is implemented as: • a single far-from-nadir image datasetis evaluated using 2 ...

  14. Final guidance document for extended Level 2 PSA Volume 1. Summary report for external hazards implementation in extended L2 PSA, validation of SAMG strategy and complement of ASAMPSA2 L2PSA guidance

    International Nuclear Information System (INIS)

    Loeffler, H.; Raimond, E.

    2016-01-01

    The present document is a summary of the deliverables produced within the ASAMPSA-E project for extended L2 PSA. These deliverables are: D30.7 vol. 2, 'Implementing external Events modelling in Level 2 PSA': D30.7 vol. 3: 'Verification and improvement of SAM strategy: D30.7 vol. 4: 'Consideration of shutdown states, spent fuel pools and recent R and D results'. Among many others, the following summary statements are provided: Analyses of external events: - No need for new methodology, - It is necessary to develop L1 PSA first and then clearly defined boundary conditions for the L2 PSA must be generated, - The remaining challenge is how to address adverse environmental conditions due to external hazards. Multi units: - No practical methodology exists to treat the problem, - A new methodology is necessary to be developed first for the L1 PSA. This should, from the beginning, take into account the specific needs of L2 PSA so that the boundary conditions for subsequent level 2 analysis can be generated adequately. SAM strategies verification and improvement: - L2 PSA methodology can usefully by applied and experience exists for internal initiating events L2 PSA, - How to address adverse environmental conditions due to external hazards - needs for new methodology or examples of experience, - How to model the decision process when there is a conflict of interest - needs for new methodology or examples of experience. For L2 PSA in shutdown states with open RPV, some new technical issues (fission product release, thermal load to structures above RPV) have to be addressed. Spent fuel pool issues have been developed, in particular: - Heat load from the melting spent fuel to structures above (e.g. to the containment roof) is a severe challenge for the plant and for the present-day, methodology is missing. Recent R and D achievements with relevance for L2 PSA: - Basic research has been continued in the radiochemistry (iodine and ruthenium chemistry) field, but the existing

  15. Strongly interacting Fermi gases

    Directory of Open Access Journals (Sweden)

    Bakr W.

    2013-08-01

    Full Text Available Strongly interacting gases of ultracold fermions have become an amazingly rich test-bed for many-body theories of fermionic matter. Here we present our recent experiments on these systems. Firstly, we discuss high-precision measurements on the thermodynamics of a strongly interacting Fermi gas across the superfluid transition. The onset of superfluidity is directly observed in the compressibility, the chemical potential, the entropy, and the heat capacity. Our measurements provide benchmarks for current many-body theories on strongly interacting fermions. Secondly, we have studied the evolution of fermion pairing from three to two dimensions in these gases, relating to the physics of layered superconductors. In the presence of p-wave interactions, Fermi gases are predicted to display toplogical superfluidity carrying Majorana edge states. Two possible avenues in this direction are discussed, our creation and direct observation of spin-orbit coupling in Fermi gases and the creation of fermionic molecules of 23Na 40K that will feature strong dipolar interactions in their absolute ground state.

  16. A strong comeback

    International Nuclear Information System (INIS)

    Marier, D.

    1992-01-01

    This article presents the results of a financial rankings survey which show a strong economic activity in the independent energy industry. The topics of the article include advisor turnover, overseas banks, and the increase in public offerings. The article identifies the top project finance investors for new projects and restructurings and rankings for lenders

  17. [External cephalic version].

    Science.gov (United States)

    Navarro-Santana, B; Duarez-Coronado, M; Plaza-Arranz, J

    2016-08-01

    To analyze the rate of successful external cephalic versions in our center and caesarean sections that would be avoided with the use of external cephalic versions. From January 2012 to March 2016 external cephalic versions carried out at our center, which were a total of 52. We collected data about female age, gestational age at the time of the external cephalic version, maternal body mass index (BMI), fetal variety and situation, fetal weight, parity, location of the placenta, amniotic fluid index (ILA), tocolysis, analgesia, and newborn weight at birth, minor adverse effects (dizziness, hypotension and maternal pain) and major adverse effects (tachycardia, bradycardia, decelerations and emergency cesarean section). 45% of the versions were unsuccessful and 55% were successful. The percentage of successful vaginal delivery in versions was 84% (4% were instrumental) and 15% of caesarean sections. With respect to the variables studied, only significant differences in birth weight were found; suggesting that birth weight it is related to the outcome of external cephalic version. Probably we did not find significant differences due to the number of patients studied. For women with breech presentation, we recommend external cephalic version before the expectant management or performing a cesarean section. The external cephalic version increases the proportion of fetuses in cephalic presentation and also decreases the rate of caesarean sections.

  18. Piezosurgery in External Dacryocystorhinostomy.

    Science.gov (United States)

    Czyz, Craig N; Fowler, Amy M; Dutton, Jonathan J; Cahill, Kenneth V; Foster, Jill A; Hill, Robert H; Everman, Kelly R; Nabavi, Cameron B

    Dacryocystorhinostomy (DCR) can be performed via an external or endoscopic approach. The use of ultrasonic or piezosurgery has been well described for endoscopic DCRs but is lacking for external DCRs. This study presents a case series of external DCRs performed using piezosurgery evaluating results and complications. Prospective, consecutive case series of patients undergoing primary external DCR for lacrimal drainage insufficiency. A standard external DCR technique was used using 1 of 2 piezosurgery systems for all bone incision. All patients received silicone intubation to the lacrimal system. Surgical outcome was measured in terms of patient-reported epiphora as follows: 1) complete resolution, 2) improvement >50%, 3) improvement 50% improvement. There were 4 patients (7%) who had <50% improvement. There was 1 (2%) intraoperative complication and 2 (4%) postoperative complications recorded. Piezourgery is a viable modality for performing external DCRs. The lack of surgical complications shows a potential for decreased soft tissues damage. The surgical success rate based on patient-reported epiphora is similar to those published for mechanical external DCRs. This modality may benefit the novice surgeon in the reduction of soft and mucosal tissue damage.

  19. Strong moduli stabilization and phenomenology

    CERN Document Server

    Dudas, Emilian; Mambrini, Yann; Mustafayev, Azar; Olive, Keith A

    2013-01-01

    We describe the resulting phenomenology of string theory/supergravity models with strong moduli stabilization. The KL model with F-term uplifting, is one such example. Models of this type predict universal scalar masses equal to the gravitino mass. In contrast, A-terms receive highly suppressed gravity mediated contributions. Under certain conditions, the same conclusion is valid for gaugino masses, which like A-terms, are then determined by anomalies. In such models, we are forced to relatively large gravitino masses (30-1000 TeV). We compute the low energy spectrum as a function of m_{3/2}. We see that the Higgs masses naturally takes values between 125-130 GeV. The lower limit is obtained from the requirement of chargino masses greater than 104 GeV, while the upper limit is determined by the relic density of dark matter (wino-like).

  20. Electrophoresis in strong electric fields.

    Science.gov (United States)

    Barany, Sandor

    2009-01-01

    Two kinds of non-linear electrophoresis (ef) that can be detected in strong electric fields (several hundred V/cm) are considered. The first ("classical" non-linear ef) is due to the interaction of the outer field with field-induced ionic charges in the electric double layer (EDL) under conditions, when field-induced variations of electrolyte concentration remain to be small comparatively to its equilibrium value. According to the Shilov theory, the non-linear component of the electrophoretic velocity for dielectric particles is proportional to the cubic power of the applied field strength (cubic electrophoresis) and to the second power of the particles radius; it is independent of the zeta-potential but is determined by the surface conductivity of particles. The second one, the so-called "superfast electrophoresis" is connected with the interaction of a strong outer field with a secondary diffuse layer of counterions (space charge) that is induced outside the primary (classical) diffuse EDL by the external field itself because of concentration polarization. The Dukhin-Mishchuk theory of "superfast electrophoresis" predicts quadratic dependence of the electrophoretic velocity of unipolar (ionically or electronically) conducting particles on the external field gradient and linear dependence on the particle's size in strong electric fields. These are in sharp contrast to the laws of classical electrophoresis (no dependence of V(ef) on the particle's size and linear dependence on the electric field gradient). A new method to measure the ef velocity of particles in strong electric fields is developed that is based on separation of the effects of sedimentation and electrophoresis using videoimaging and a new flowcell and use of short electric pulses. To test the "classical" non-linear electrophoresis, we have measured the ef velocity of non-conducting polystyrene, aluminium-oxide and (semiconductor) graphite particles as well as Saccharomice cerevisiae yeast cells as a

  1. Strong Electroweak Symmetry Breaking

    CERN Document Server

    Grinstein, Benjamin

    2011-01-01

    Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...

  2. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.

    2011-01-01

    We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

  3. Performance of Multiple Risk Assessment Tools to Predict Mortality for Adult Respiratory Distress Syndrome with Extracorporeal Membrane Oxygenation Therapy: An External Validation Study Based on Chinese Single-center Data

    Directory of Open Access Journals (Sweden)

    Lei Huang

    2016-01-01

    Conclusions: The RESP, APCHAE II, and SOFA scorings systems show good predictive value for intra-hospital survival of ARDS patients treated with ECMO in our single-center evaluation. Future validation should include a larger study with either more patients' data at single-center or by integration of domestic multi-center data. Development of a scoring system with national characteristics might be warranted.

  4. Validation of the D'amico risk groups classification, valuation of high-risk patients with or without hormonal therapy and complications of patients with adenocarcinoma of the prostate, after treatment with external radiotherapy, Hospital Calderon Guardia, 2003-2004

    International Nuclear Information System (INIS)

    Lopez Arias, Ever Roy

    2008-01-01

    D'amico risk groups have been classified to estimate the probability of biochemical recurrence after treatment for localized prostate cancer. The evolution of patients that have received external radiotherapy were analyzed according to the risk group. The medical records of 50 patients between 2003 and 2004 have been assessed and has observed the evolution of Prostatic Specific Antigen after treatment ends, at Hospital Calderon Guardia. Adverse reactions resulting from radiotherapy treatment and the organs most affected by the same have been documented nith the possibility to compare the results of similar studies in the literature. The best performance is given by receiving concomitant hormonal therapy that high risk patients of D'amico without receiving. (author) [es

  5. Automated External Defibrillator

    Science.gov (United States)

    ... leads to a 10 percent reduction in survival. Training To Use an Automated External Defibrillator Learning how to use an AED and taking a CPR (cardiopulmonary resuscitation) course are helpful. However, if trained ...

  6. Energy policy and externalities

    International Nuclear Information System (INIS)

    Bertel, E.; Fraser, P.

    2002-01-01

    External costs of energy have been assessed in a number of authoritative and reliable studies based upon widely accepted methodologies such as life cycle analysis (LCA). However, although those costs are recognised by most stakeholders and decision makers, results from analytical work on externalities and LCA studies are seldom used in policy making. The International Energy Agency (IEA) and the Nuclear Energy Agency (NEA) convened a joint workshop in November 2001 to offer experts and policy makers an opportunity to present state-of-the-art results from analytical work on externalities and debate issues related to the relevance of external costs and LCA for policy-making purposes. The findings from the workshop highlight the need for further work in the field and the potential rote of international organisations like the IEA and the NEA in this context. (authors)

  7. Externally Verifiable Oblivious RAM

    Directory of Open Access Journals (Sweden)

    Gancher Joshua

    2017-04-01

    Full Text Available We present the idea of externally verifiable oblivious RAM (ORAM. Our goal is to allow a client and server carrying out an ORAM protocol to have disputes adjudicated by a third party, allowing for the enforcement of penalties against an unreliable or malicious server. We give a security definition that guarantees protection not only against a malicious server but also against a client making false accusations. We then give modifications of the Path ORAM [15] and Ring ORAM [9] protocols that meet this security definition. These protocols both have the same asymptotic runtimes as the semi-honest original versions and require the external verifier to be involved only when the client or server deviates from the protocol. Finally, we implement externally verified ORAM, along with an automated cryptocurrency contract to use as the external verifier.

  8. External wave-launcher study. Final report

    International Nuclear Information System (INIS)

    1983-01-01

    The rationale for liquid dielectrically-loaded external wave-guide launchers is discussed. The arguments are strongly indicative that a liquid dielectric-filled waveguide system could be a practical technique for launching ICRH power into a fusion reactor. A detailed summary of the work performed in the study is presented

  9. Weld pool visual sensing without external illumination

    DEFF Research Database (Denmark)

    Liu, Jinchao; Fan, Zhun; Olsen, Soren Ingvor

    2011-01-01

    Visual sensing in arc welding has become more and more important, but still remains challenging because of the harsh environment with extremely strong illumination from the arc. This paper presents a low-cost camera-based sensor system, without using external Illumination, but nevertheless able...

  10. Strongly intensive quantities

    International Nuclear Information System (INIS)

    Gorenstein, M. I.; Gazdzicki, M.

    2011-01-01

    Analysis of fluctuations of hadron production properties in collisions of relativistic particles profits from use of measurable intensive quantities which are independent of system size variations. The first family of such quantities was proposed in 1992; another is introduced in this paper. Furthermore we present a proof of independence of volume fluctuations for quantities from both families within the framework of the grand canonical ensemble. These quantities are referred to as strongly intensive ones. Influence of conservation laws and resonance decays is also discussed.

  11. Strong-coupling approximations

    International Nuclear Information System (INIS)

    Abbott, R.B.

    1984-03-01

    Standard path-integral techniques such as instanton calculations give good answers for weak-coupling problems, but become unreliable for strong-coupling. Here we consider a method of replacing the original potential by a suitably chosen harmonic oscillator potential. Physically this is motivated by the fact that potential barriers below the level of the ground-state energy of a quantum-mechanical system have little effect. Numerically, results are good, both for quantum-mechanical problems and for massive phi 4 field theory in 1 + 1 dimensions. 9 references, 6 figures

  12. A novel strong tracking finite-difference extended Kalman filter for nonlinear eye tracking

    Institute of Scientific and Technical Information of China (English)

    ZHANG ZuTao; ZHANG JiaShu

    2009-01-01

    Non-Intrusive methods for eye tracking are Important for many applications of vision-based human computer interaction. However, due to the high nonlinearity of eye motion, how to ensure the robust-ness of external interference and accuracy of eye tracking poses the primary obstacle to the integration of eye movements into today's interfaces. In this paper, we present a strong tracking finite-difference extended Kalman filter algorithm, aiming to overcome the difficulty In modeling nonlinear eye tracking. In filtering calculation, strong tracking factor is introduced to modify a priori covariance matrix and im-prove the accuracy of the filter. The filter uses finite-difference method to calculate partial derivatives of nonlinear functions for eye tracking. The latest experimental results show the validity of our method for eye tracking under realistic conditions.

  13. Seven-day mortality can be predicted in medical patients by blood pressure, age, respiratory rate, loss of independence, and peripheral oxygen saturation (the PARIS score: a prospective cohort study with external validation.

    Directory of Open Access Journals (Sweden)

    Mikkel Brabrand

    Full Text Available Most existing risk stratification systems predicting mortality in emergency departments or admission units are complex in clinical use or have not been validated to a level where use is considered appropriate. We aimed to develop and validate a simple system that predicts seven-day mortality of acutely admitted medical patients using routinely collected variables obtained within the first minutes after arrival.This observational prospective cohort study used three independent cohorts at the medical admission units at a regional teaching hospital and a tertiary university hospital and included all adult (≥ 15 years patients. Multivariable logistic regression analysis was used to identify the clinical variables that best predicted the endpoint. From this, we developed a simplified model that can be calculated without specialized tools or loss of predictive ability. The outcome was defined as seven-day all-cause mortality. 76 patients (2.5% met the endpoint in the development cohort, 57 (2.0% in the first validation cohort, and 111 (4.3% in the second. Systolic blood Pressure, Age, Respiratory rate, loss of Independence, and peripheral oxygen Saturation were associated with the endpoint (full model. Based on this, we developed a simple score (range 0-5, ie, the PARIS score, by dichotomizing the variables. The ability to identify patients at increased risk (discriminatory power and calibration was excellent for all three cohorts using both models. For patients with a PARIS score ≥ 3, sensitivity was 62.5-74.0%, specificity 85.9-91.1%, positive predictive value 11.2-17.5%, and negative predictive value 98.3-99.3%. Patients with a score ≤ 1 had a low mortality (≤ 1%; with 2, intermediate mortality (2-5%; and ≥ 3, high mortality (≥ 10%.Seven-day mortality can be predicted upon admission with high sensitivity and specificity and excellent negative predictive values.

  14. Strongly disordered superconductors

    International Nuclear Information System (INIS)

    Muttalib, K.A.

    1982-01-01

    We examine some universal effects of strong non-magnetic disorder on the electron-phonon and electron-electron interactions in a superconductor. In particular we explicitly take into account the effect of slow diffusion of electrons in a disordered medium by working in an exact impurity eigenstate representation. We find that the normal diffusion of electrons characterized by a constant diffusion coefficient does not lead to any significant correction to the electron-phonon or the effective electron-electron interactions in a superconductor. We then consider sufficiently strong disorder where Anderson localization of electrons becomes important and determine the effect of localization on the electron-electron interactions. We find that due to localization, the diffusion of electrons becomes anomalous in the sense that the diffusion coefficient becomes scale dependent. This results in an increase in the effective electron-electron interaction with increasing disorder. We propose that this provides a natural explanation for the unusual sensitivity of the transition temperature T/sub c/ of the high T/sub c/ superconductors (T/sub c/ > 10 0 K) to damage effects

  15. Strong Coupling Holography

    CERN Document Server

    Dvali, Gia

    2009-01-01

    We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4+d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this effect for orbifold planes, as well as for the solitonic branes and string theoretic D-branes. In all cases the emergence of a 4D strong coupling scale from bulk holography is a persistent phenomenon. The effect turns out to be insensitive even to such extreme deformations of the brane action that seemingly shield 4D theory from the bulk gravity effects. A well understood example of such deformation is given by large 4D Einstein term in the 3-brane action, which is known to suppress the strength of 5D gravity at short distances and change the 5D Newton's law into the four-dimensional one. Nevertheless, we observe that the ...

  16. Strongly interacting matter in magnetic fields

    CERN Document Server

    Landsteiner, Karl; Schmitt, Andreas; Yee, Ho-Ung

    2013-01-01

    The physics of strongly interacting matter in an external magnetic field is presently emerging as a topic of great cross-disciplinary interest for particle, nuclear, astro- and condensed matter physicists. It is known that strong magnetic fields are created in heavy ion collisions, an insight that has made it possible to study a variety of surprising and intriguing phenomena that emerge from the interplay of quantum anomalies, the topology of non-Abelian gauge fields, and the magnetic field. In particular, the non-trivial topological configurations of the gluon field induce a non-dissipative electric current in the presence of a magnetic field. These phenomena have led to an extended formulation of relativistic hydrodynamics, called chiral magnetohydrodynamics. Hitherto unexpected applications in condensed matter physics include graphene and topological insulators. Other fields of application include astrophysics, where strong magnetic fields exist in magnetars and pulsars. Last but not least, an important ne...

  17. LIGO: The strong belief

    CERN Multimedia

    Antonella Del Rosso

    2016-01-01

    Twenty years of designing, building and testing a number of innovative technologies, with the strong belief that the endeavour would lead to a historic breakthrough. The Bulletin publishes an abstract of the Courier’s interview with Barry Barish, one of the founding fathers of LIGO.   The plots show the signals of gravitational waves detected by the twin LIGO observatories at Livingston, Louisiana, and Hanford, Washington. (Image: Caltech/MIT/LIGO Lab) On 11 February, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations published a historic paper in which they showed a gravitational signal emitted by the merger of two black holes. These results come after 20 years of hard work by a large collaboration of scientists operating the two LIGO observatories in the US. Barry Barish, Linde Professor of Physics, Emeritus at the California Institute of Technology and former Director of the Global Design Effort for the Internat...

  18. Strongly interacting Higgs bosons

    International Nuclear Information System (INIS)

    Appelquist, T.; Bernard, C.

    1980-01-01

    The sensitivity of present-energy weak interactions to a strongly interacting heavy-Higgs-boson sector is discussed. The gauged nonlinear sigma model, which is the limit of the linear model as the Higgs-boson mass goes to infinity, is used to organize and catalogue all possible heavy-Higgs-boson effects. As long as the SU(2)/sub L/ x SU(2)/sub R/ symmetry of the Higgs sector is preserved, these effects are found to be small, of the order of the square of the gauge coupling times logarithms (but not powers) of the Higgs-boson mass divided by the W mass. We work in the context of a simplified model with gauge group SU(2)/sub L/; the extension to SU(2)/sub L/ x U(1) is briefly discussed

  19. Determination of external measurements in aim to solve inverse heat conduction problem in piping

    International Nuclear Information System (INIS)

    Blanc, G.; Raynaud, M.; Chau, T.H.

    1995-01-01

    The inverse heat conduction problem (IHCP) to be solved involves with the reconstruction of unknown thermal loadings applied on piping internal wall. Only external temperature measurements are available as data. Different approaches can be found in the literature for solving this ill-posed problem. The most frequently used among them is the function specification method proposed by Professor BECK. However, for multidimensional IHCP, the accuracy of the solution strongly depends on the number of sensors and their location. This work focuses on the determination of minimal number and locations of the external thermocouples to get the most complete estimation of internal heat flux in a straight pipe. It more particularly concerns the preparation of experimental validation tests which will be performed on the ESTHER mock-up of Electricite de France (EDF). (authors). 4 refs., 9 figs

  20. External validation of the fatty liver index and lipid accumulation product indices, using 1H-magnetic resonance spectroscopy, to identify hepatic steatosis in healthy controls and obese, insulin-resistant individuals.

    Science.gov (United States)

    Cuthbertson, Daniel J; Weickert, Martin O; Lythgoe, Daniel; Sprung, Victoria S; Dobson, Rebecca; Shoajee-Moradie, Fariba; Umpleby, Margot; Pfeiffer, Andreas F H; Thomas, E Louise; Bell, Jimmy D; Jones, Helen; Kemp, Graham J

    2014-11-01

    Simple clinical algorithms including the fatty liver index (FLI) and lipid accumulation product (LAP) have been developed as surrogate markers for non-alcoholic fatty liver disease (NAFLD), constructed using (semi-quantitative) ultrasonography. This study aimed to validate FLI and LAP as measures of hepatic steatosis, as determined quantitatively by proton magnetic resonance spectroscopy (1H-MRS). Data were collected from 168 patients with NAFLD and 168 controls who had undergone clinical, biochemical and anthropometric assessment. Values of FLI and LAP were determined and assessed both as predictors of the presence of hepatic steatosis (liver fat>5.5%) and of actual liver fat content, as measured by 1H-MRS. The discriminative ability of FLI and LAP was estimated using the area under the receiver operator characteristic curve (AUROC). As FLI can also be interpreted as a predictive probability of hepatic steatosis, we assessed how well calibrated it was in our cohort. Linear regression with prediction intervals was used to assess the ability of FLI and LAP to predict liver fat content. Further validation was provided in 54 patients with type 2 diabetes mellitus. FLI, LAP and alanine transferase discriminated between patients with and without steatosis with an AUROC of 0.79 (IQR=0.74, 0.84), 0.78 (IQR=0.72, 0.83) and 0.83 (IQR=0.79, 0.88) respectively although could not quantitatively predict liver fat. Additionally, the algorithms accurately matched the observed percentages of patients with hepatic steatosis in our cohort. FLI and LAP may be used to identify patients with hepatic steatosis clinically or for research purposes but could not predict liver fat content. © 2014 European Society of Endocrinology.

  1. Malignant external otitis

    International Nuclear Information System (INIS)

    Dupuch, K.M.; Iryboz, T.; Firat, M.; Levy, C.; Tubiana, J.M.

    1991-01-01

    This paper illustrates the value of CT and MR in early diagnosis and spread of malignant external otitis. The authors retrospectively analyzed 15 patients with proved malignant external otitis examined with postcontrast high-resolution CT (15/15) and MR (6/15) (T1- and T2-weighting). Gallium studies were done in 6/15 patients. Early diagnosis was made when CT demonstrated a soft-tissue mass of the external auditory canal associated with scattered zones of cortical bone erosions (13/15). Spread of the disease was better delineated by MR than CT, especially skull base extension (6/15). Temporomandibular joint involvement with extension into parotid or/and masticator spaces 6/15 was as well detected with CT as with MR. If CT remains the first and best procedure for diagnosis, MR - despite its cost - appears a good procedure to depict exact anatomic spread, allowing therapeutic management

  2. Productivity Change and Externalities

    DEFF Research Database (Denmark)

    Kravtsova, Victoria

    2014-01-01

    This paper contributes to the analysis of the impact of externalities on the host country's total factor productivity by taking into account different dimensions of spillover effects. Namely, engagement in exporting and foreign ownership is generally perceived as being beneficial to individual...... firms and the economy as a whole. The approach used in the current research accounts for different internal as well as external factors that individual firms face and evaluates the effect on changes in productivity, technology as well as the efficiency of domestic firms. The empirical analysis focuses...... on Hungary. While the country leads the group of post-socialist countries in the amount of attracted foreign direct investments (FDI) the effect of this policy on the economy remains unclear. The research finds that different externalities play a different role in productivity, technological and efficiency...

  3. Metasurface external cavity laser

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Luyao, E-mail: luyaoxu.ee@ucla.edu; Curwen, Christopher A.; Williams, Benjamin S. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); California NanoSystems Institute, University of California, Los Angeles, California 90095 (United States); Hon, Philip W. C.; Itoh, Tatsuo [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Chen, Qi-Sheng [Northrop Grumman Aerospace Systems, Redondo Beach, California 90278 (United States)

    2015-11-30

    A vertical-external-cavity surface-emitting-laser is demonstrated in the terahertz range, which is based upon an amplifying metasurface reflector composed of a sub-wavelength array of antenna-coupled quantum-cascade sub-cavities. Lasing is possible when the metasurface reflector is placed into a low-loss external cavity such that the external cavity—not the sub-cavities—determines the beam properties. A near-Gaussian beam of 4.3° × 5.1° divergence is observed and an output power level >5 mW is achieved. The polarized response of the metasurface allows the use of a wire-grid polarizer as an output coupler that is continuously tunable.

  4. The External Mind

    DEFF Research Database (Denmark)

    , Extended Mind and Distributed Cognition by Claudio Paolucci pp. 69-96 The Social Horizon of Embodied Language and Material Symbols by Riccardo Fusaroli pp. 97-123 Semiotics and Theories of Situated/Distributed Action and Cognition: a Dialogue and Many Intersections by Tommaso Granelli pp. 125-167 Building......The External Mind: an Introduction by Riccardo Fusaroli, Claudio Paolucci pp. 3-31 The sign of the Hand: Symbolic Practices and the Extended Mind by Massimiliano Cappuccio, Michael Wheeler pp. 33-55 The Overextended Mind by Shaun Gallagher pp. 57-68 The "External Mind": Semiotics, Pragmatism...

  5. Strong-interaction nonuniversality

    International Nuclear Information System (INIS)

    Volkas, R.R.; Foot, R.; He, X.; Joshi, G.C.

    1989-01-01

    The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements

  6. John Strong (1941 - 2006)

    CERN Multimedia

    Wickens, F

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on Monday 31st July, a few days before his 65th birthday John started his career working with a group from Westfield College, under the leadership of Ted Bellamy. He obtained his PhD and spent the early part of his career on experiments at Rutherford Appleton Laboratory (RAL), but after the early 1970s his research was focussed on experiments in CERN. Over the years he made a number of notable contributions to experiments in CERN: The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras to record the sparks in the spark chambers; He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems; He was responsible for the second level trigger system for the ALEPH detector and spent five years leading a team that designed and built the system, which ran for twelve years with only minor interventions. Following ALEPH he tur...

  7. Stirring Strongly Coupled Plasma

    CERN Document Server

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim

    2009-01-01

    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  8. Topics in strong Langmuir turbulence

    International Nuclear Information System (INIS)

    Skoric, M.M.

    1981-01-01

    This thesis discusses certain aspects of the turbulence of a fully ionised non-isothermal plasma dominated by the Langmuir mode. Some of the basic properties of strongly turbulent plasmas are reviewed. In particular, interest is focused on the state of Langmuir turbulence, that is the turbulence of a simple externally unmagnetized plasma. The problem of the existence and dynamics of Langmuir collapse is discussed, often met as a non-linear stage of the modulational instability in the framework of the Zakharov equations (i.e. simple time-averaged dynamical equations). Possible macroscopic consequences of such dynamical turbulent models are investigated. In order to study highly non-linear collapse dynamics in its advanced stage, a set of generalized Zakharov equations are derived. Going beyond the original approximation, the author includes the effects of higher electron non-linearities and a breakdown of slow-timescale quasi-neutrality. He investigates how these corrections may influence the collapse stabilisation. Recently, it has been realised that the modulational instability in a Langmuir plasma will be accompanied by the collisionless-generation of a slow-timescale magnetic field. Accordingly, a novel physical situation has emerged which is investigated in detail. The stability of monochromatic Langmuir waves in a self-magnetized Langmuir plasma, is discussed, and the existence of a novel magneto-modulational instability shown. The wave collapse dynamics is investigated and a physical interpretation of the basic results is given. A problem of the transient analysis of an interaction of time-dependent electromagnetic pulses with linear cold plasma media is investigated. (Auth.)

  9. The External Networking Behaviour of Public Managers

    DEFF Research Database (Denmark)

    Hansen, Morten Balle; Villadsen, Anders Ryom

    2017-01-01

    There has been an increasing focus on managerial external networking behaviour within public administration. While most previous quantitative research has analysed such behaviour one-dimensionally, we suggest a two-dimensional conceptualization based on the concepts of weak and strong ties....... Utilizing measures resembling previous research, we explore the utility of the approach in an exploratory study of Danish local government. Our findings suggest that the two dimensions of external networking behaviour are distinct. We discuss our approach compared to previous approaches and argue...

  10. Criterion Validity of the Child's Challenging Behavior Scale, Version 2 (CCBS-2).

    Science.gov (United States)

    Bourke-Taylor, Helen M; Cordier, Reinie; Pallant, Julie F

    The Child's Challenging Behavior Scale, Version 2 (CCBS-2), measures maternal rating of a child's challenging behaviors that compromise maternal mental health. The CCBS-2, the Child Behavior Checklist (CBCL), and the Strengths and Difficulties Questionnaire (SDQ) were compared in a sample of typically developing young Australian children. Criterion validity was investigated by correlating the CCBS-2 with "gold standard" measures (CBCL and SDQ subscales). Data were collected in a cross-sectional survey of mothers (N = 336) of children ages 3-9 yr. Correlations with the CBCL externalizing subscales demonstrated moderate (ρ = .46) to strong (ρ = .66) correlations. Correlations with the SDQ externalizing behaviors subscales were moderate (ρ = .35) to strong (ρ = .60). The criterion validity established in this study strengthens the psychometric properties that support ongoing development of the CCBS-2 as an efficient tool that may identify children in need of further evaluation. Copyright © 2018 by the American Occupational Therapy Association, Inc.

  11. External costs of electricity

    International Nuclear Information System (INIS)

    Rabl, A.; Spadaro, J.V.

    2005-01-01

    This article presents a synthesis of the ExternE project (External costs of Energy) of the European community about the external costs of power generation. Pollution impacts are calculated using an 'impact pathways' analysis, i.e. an analysis of the emission - dispersion - dose-response function - cost evaluation chain. Results are presented for different fuel cycles (with several technological variants) with their confidence intervals. The environmental impact costs are particularly high for coal: for instance, in France, for coal-fired power plants it is of the same order as the electricity retail price. For natural gas, this cost is about a third of the one for coal. On the contrary, the environmental impact costs for nuclear and renewable energies are low, typically of few per cent of the electricity price. The main part of these costs corresponds to the sanitary impacts, in particular the untimely mortality. In order to avoid any controversy about the cost evaluation of mortality, the reduction of the expectation of life due to the different fuel cycles is also indicated and the risks linked with nuclear energy are presented using several comparisons. (J.S.)

  12. On parabolic external maps

    DEFF Research Database (Denmark)

    Lomonaco, Luna; Petersen, Carsten Lunde; Shen, Weixiao

    2017-01-01

    We prove that any C1+BV degree d ≥ 2 circle covering h having all periodic orbits weakly expanding, is conjugate by a C1+BV diffeomorphism to a metrically expanding map. We use this to connect the space of parabolic external maps (coming from the theory of parabolic-like maps) to metrically expan...

  13. Stochastic Control - External Models

    DEFF Research Database (Denmark)

    Poulsen, Niels Kjølstad

    2005-01-01

    This note is devoted to control of stochastic systems described in discrete time. We are concerned with external descriptions or transfer function model, where we have a dynamic model for the input output relation only (i.e.. no direct internal information). The methods are based on LTI systems...

  14. Plasmon instability under four external fields

    International Nuclear Information System (INIS)

    Pereira, R.B.; Fonseca, A.L.A.; Nunes, O.A.C.

    1998-01-01

    The plasmon instability in a laboratory produced plasma in the presence of four external fields, namely two laser fields, one strong magnetic field and one static electric field, is discussed. The method of unitary transformations is used to transform the problem of electron motion under the four external fields to that of an electron in the presence only of crossed electric and magnetic fields. A kinetic equation for the plasmon population is derived from which the damping (amplification) rate is calculated. We found that the joint action of the four fields results in a relatively larger amplification rate for some values of the static electric field in contrast to the case where no electric field is present. It was also found that the plasmon growth rate favors plasmon wave vectors in an extremely narrow band i.e., the plasmon instability in four external fields is a very selective mechanism for plasmon excitation. (author)

  15. ExternE transport methodology for external cost evaluation of air pollution

    DEFF Research Database (Denmark)

    Jensen, S. S.; Berkowicz, R.; Brandt, J.

    The report describes how the human exposure estimates based on NERI's human exposure modelling system (AirGIS) can improve the Danish data used for exposure factors in the ExternE Transport methodology. Initially, a brief description of the ExternE Tranport methodology is given and it is summarised...

  16. Some dynamical properties of very strong double layers in a triple plasma device

    International Nuclear Information System (INIS)

    Carpenter, T.; Torven, S.

    1987-01-01

    Experimental results on three dynamic properties of very strong double layers observed in a triple plasma device are presented. First, it is observed that when an inductance of sufficient size is inserted in series with the external bias supply used to produce the double layer, disruptions in the plasma current occur accompanied by disruptions in the double layer potential. Second, it is observed that with all external reactances reduced as much as possible, a sort of jitter-motion occurs in the position of the double layer around its equilibrium position. Third, when the external bias supply is pulsed, the initial potential distribution is observed to have an essentially uniform slope, as in the case of a vacuum capacitor. The disruption phenomenon may be explained in terms of the behavior of the potential structure as a function of the bias voltage and this explanation is discussed along with the experimental evidence for its validity. A comparable understanding of the other two phenomena has not been achieved, but in both cases there are qualitative difference between the behavior reported here and what has been observed in Q-machines and these difference are discussed. (author)

  17. External Monitoring and Dynamic Behavior in Mutual Funds

    Directory of Open Access Journals (Sweden)

    Jian Wang

    2016-01-01

    Full Text Available This paper studies the impact of external monitoring on the behavior in mutual funds. Specifically, we investigate how and why external monitoring can alleviate contracting inefficiency caused by information asymmetry between investors and the manager. It is shown that efficiency loss emerges when investors contract with the manager just relying on her investment return history. The establishment of external monitoring that provides investors more information about the manager’s ability can improve contracting efficiency, which converges to first-best as external monitoring strengthens. These results provide strong support for tightening supervision in mutual fund industry.

  18. Strong environmental coupling in a Josephson parametric amplifier

    International Nuclear Information System (INIS)

    Mutus, J. Y.; White, T. C.; Barends, R.; Chen, Yu; Chen, Z.; Chiaro, B.; Dunsworth, A.; Jeffrey, E.; Kelly, J.; Neill, C.; O'Malley, P. J. J.; Roushan, P.; Sank, D.; Vainsencher, A.; Wenner, J.; Cleland, A. N.; Martinis, John M.; Megrant, A.; Sundqvist, K. M.

    2014-01-01

    We present a lumped-element Josephson parametric amplifier designed to operate with strong coupling to the environment. In this regime, we observe broadband frequency dependent amplification with multi-peaked gain profiles. We account for this behavior using the “pumpistor” model which allows for frequency dependent variation of the external impedance. Using this understanding, we demonstrate control over the complexity of gain profiles through added variation in the environment impedance at a given frequency. With strong coupling to a suitable external impedance, we observe a significant increase in dynamic range, and large amplification bandwidth up to 700 MHz giving near quantum-limited performance.

  19. Validade de construto da versão brasileira do Inventário Espectral de Externalização: evidências a partir de uma amostra de estudantes universitários Construct validity of the Brazilian version of the Externalizing Spectrum Inventory: evidence from a university student sample

    Directory of Open Access Journals (Sweden)

    Hudson Wander de Carvalho

    2010-01-01

    Full Text Available CONTEXTO: Externalização é uma dimensão das diferenças individuais que dá substrato e unifica traços impulsivos e agressivos de personalidade a transtornos mentais relacionados ao uso de substância e à conduta antissocial. OBJETIVOS: O presente estudo objetivou apresentar indicadores de validade de construto da versão brasileira do Inventário Espectral de Externalização. MÉTODO: Trata-se de um estudo psicométrico de orientação correlacional. Foram utilizadas duas técnicas clássicas de representação de construto: análise exploratória de fatores comuns e análise de consistência interna. A amostra consistiu de 258 participantes de ambos os sexos, provenientes de diferentes cursos universitários de duas instituições públicas do estado de Minas Gerais. RESULTADOS: A análise fatorial resultou em um modelo de um fator de segunda ordem (Externalização com três fatores de primeira ordem (dimensões de agressão, de uso de substância e de impulsividade/alienação. Os coeficientes alfa mostraram-se bastante elevados, com índices acima de 0,9 tanto para os três fatores de primeira ordem quanto para o fator geral. CONCLUSÃO: Combinados, os resultados trazem evidências de validade e de fidedignidade para a versão brasileira do Inventário Espectral de Externalização no que tange à sua aplicabilidade a estudantes universitários.BACKGROUND: Externalizing is a dimension of individual differences that undergirds and unites aggressive and impulsive personality traits to psychopathological disorders related to substance use and antisocial behavior. OBJECTIVES: The present study aims to establish parameters of construct validity for the Brazilian version of the Externalizing Spectrum Inventory. METHOD: This is a psychometrical correlacional study design. Two classical techniques of construct representation were implemented: unweighted least squares exploratory factor analysis and internal consistency analysis. The sample

  20. Environmental external effects from wind power based on the EU ExternE methodology

    DEFF Research Database (Denmark)

    Ibsen, Liselotte Schleisner; Nielsen, Per Sieverts

    1998-01-01

    of the Danish part of the project is to implement the framework for externality evaluation, for three different power plants located in Denmark. The paper will focus on the assessment of the impacts of the whole fuel cycles for wind, natural gas and biogas. Priority areas for environmental impact assessment......The European Commission has launched a major study project, ExternE, to develop a methodology to quantify externalities. A “National Implementation Phase”, was started under the Joule II programme with the purpose of implementing the ExternE methodology in all member states. The main objective...

  1. External corners as heat bridges

    Energy Technology Data Exchange (ETDEWEB)

    Berber, J.

    1984-08-01

    The maximum additional heat loss in vertical external corners depending on wall thickness is determined. In order to amire at a low k-value, a much smaller wall thickness is required in externally insulated walls than in monolithic constructions; the greater loss of heat bridge with external insulation stands in contrast to a higher loss in thick, monolithic walls. In relation to total losses, the additional losses through external corners are practically negligible.

  2. [External pancreatic fistulas management].

    Science.gov (United States)

    Stepan, E V; Ermolov, A S; Rogal', M L; Teterin, Yu S

    The main principles of treatment of external postoperative pancreatic fistulas are viewed in the article. Pancreatic trauma was the reason of pancreatic fistula in 38.7% of the cases, operations because of acute pancreatitis - in 25.8%, and pancreatic pseudocyst drainage - in 35.5%. 93 patients recovered after the treatment. Complex conservative treatment of EPF allowed to close fistulas in 74.2% of the patients with normal patency of the main pancreatic duct (MPD). The usage of octreotide 600-900 mcg daily for at least 5 days to decrease pancreatic secretion was an important part of the conservative treatment. Endoscopic papillotomy was performed in patients with major duodenal papilla obstruction and interruption of transporting of pancreatic secretion to duodenum. Stent of the main pancreatic duct was indicated in patients with extended pancreatic duct stenosis to normalize transport of pancreatic secretion to duodenum. Surgical formation of anastomosis between distal part of the main pancreatic duct and gastro-intestinal tract was carried out when it was impossible to fulfill endoscopic stenting of pancreatic duct either because of its interruption and diastasis between its ends, or in the cases of unsuccessful conservative treatment of external pancreatic fistula caused by drainage of pseudocyst.

  3. Modal response of interior mass based upon external measurements

    International Nuclear Information System (INIS)

    Chow, C T; Eli, M; Jorgensen, B R; Woehrle, T.

    1999-01-01

    Modal response testing has been used to predict the motion of interior masses of a system in which only external instrumentation is allowed. Testing of this form may occasionally be necessary in validation of a computer model, but also has potential as a tool for validating individual assemblies in a QA process. Examination of the external frequency response and mode shapes can offer insight into interior response. The interpretation of these results is improved through parallel analytical solutions. A simple, three-mass model has been examined experimentally and analytically to demonstrate modal theory. These results show the limitations of the external measurement in predicting internal response due to transmissibility. A procedure for utilizing external testing is described. The question posed through this research is whether or not modal correlation analysis can be adapted for use in systems for which instrumentation of critical components is missing

  4. Explicating Validity

    Science.gov (United States)

    Kane, Michael T.

    2016-01-01

    How we choose to use a term depends on what we want to do with it. If "validity" is to be used to support a score interpretation, validation would require an analysis of the plausibility of that interpretation. If validity is to be used to support score uses, validation would require an analysis of the appropriateness of the proposed…

  5. External Validity: From Do-calculus to Transportability Across Populations

    Science.gov (United States)

    2012-05-01

    experiments with a different version. Their analysis is a special case of the theory developed in this paper (Petersen, 2011). A related application is...described below. 4 J. PEARL AND E. BAREINBOIM expected effect of a given intervention. Auxiliary to C, a causal model should also yield an estimand Qi(P...and used to confirm or disconfirm the model against the data. The structure of this inferential exercise is shown schematically in Figure 1. For a

  6. Conceptual Elaboration Sequencing: An External Validation Study in Nursing Education

    Science.gov (United States)

    Kinderman, Kathy T.

    2012-01-01

    Nursing education is a knowledge domain that requires higher order thinking (critical thinking) for making decisions that impact outcomes of human health. The goal of nursing education is to develop novice experts in nursing knowledge and clinical practice. In order to achieve this goal, nursing education must employ instructional approaches that…

  7. Identifying and Evaluating External Validity Evidence for Passing Scores

    Science.gov (United States)

    Davis-Becker, Susan L.; Buckendahl, Chad W.

    2013-01-01

    A critical component of the standard setting process is collecting evidence to evaluate the recommended cut scores and their use for making decisions and classifying students based on test performance. Kane (1994, 2001) proposed a framework by which practitioners can identify and evaluate evidence of the results of the standard setting from (1)…

  8. External Measures of Cognition

    Directory of Open Access Journals (Sweden)

    Osvaldo eCairo

    2011-10-01

    Full Text Available The human brain is undoubtedly the most impressive, complex and intricate organ that has evolved over time. It is also probably the least understood, and for that reason, the one that is currently attracting the most attention. In fact, the number of comparative analyses that focus on the evolution of brain size in Homo sapiens and other species has increased dramatically in recent years. In neuroscience, no other issue has generated so much interest and been the topic of so many heated debates as the difference in brain size between socially defined population groups, both its connotations and implications. For over a century, external measures of cognition have been related to intelligence. However, it is still unclear whether these measures actually correspond to cognitive abilities. In summary, this paper must be reviewed with this premise in mind.

  9. Hanford External Dosimetry Program

    International Nuclear Information System (INIS)

    Fix, J.J.

    1990-10-01

    This document describes the Hanford External Dosimetry Program as it is administered by Pacific Northwest Laboratory (PNL) in support of the US Department of Energy (DOE) and its Hanford contractors. Program services include administrating the Hanford personnel dosimeter processing program and ensuring that the related dosimeter data accurately reflect occupational dose received by Hanford personnel or visitors. Specific chapters of this report deal with the following subjects: personnel dosimetry organizations at Hanford and the associated DOE and contractor exposure guidelines; types, characteristics, and procurement of personnel dosimeters used at Hanford; personnel dosimeter identification, acceptance testing, accountability, and exchange; dosimeter processing and data recording practices; standard sources, calibration factors, and calibration processes (including algorithms) used for calibrating Hanford personnel dosimeters; system operating parameters required for assurance of dosimeter processing quality control; special dose evaluation methods applied for individuals under abnormal circumstances (i.e., lost results, etc.); and methods for evaluating personnel doses from nuclear accidents. 1 ref., 14 figs., 5 tabs

  10. Bevalac external beamline optics

    Energy Technology Data Exchange (ETDEWEB)

    Kalnins, J.G.; Krebs, G.F.; Tekawa, M.M.; Alonso, J.R.

    1987-04-01

    This handbook is intended as an aid for tuning the external particle beam (EPB) lines at the Lawrence Berkeley Laboratory's Bevalac. The information contained within will be useful to the Bevalac's Main Control Room and experimenters alike. First, some general information is given concerning the EPB lines and beam optics. Next, each beam line is described in detail: schematics of the beam line components are shown, all the variables required to run a beam transport program are presented, beam envelopes are given with wire chamber pictures and magnet currents, focal points and magnifications. Some preliminary scaling factors are then presented which should aid in choosing a given EPB magnet's current for a given central Bevalac field. Finally, some tuning hints are suggested.

  11. Bevalac external beamline optics

    International Nuclear Information System (INIS)

    Kalnins, J.G.; Krebs, G.F.; Tekawa, M.M.; Alonso, J.R.

    1987-04-01

    This handbook is intended as an aid for tuning the external particle beam (EPB) lines at the Lawrence Berkeley Laboratory's Bevalac. The information contained within will be useful to the Bevalac's Main Control Room and experimenters alike. First, some general information is given concerning the EPB lines and beam optics. Next, each beam line is described in detail: schematics of the beam line components are shown, all the variables required to run a beam transport program are presented, beam envelopes are given with wire chamber pictures and magnet currents, focal points and magnifications. Some preliminary scaling factors are then presented which should aid in choosing a given EPB magnet's current for a given central Bevalac field. Finally, some tuning hints are suggested

  12. Operationalizing Proneness to Externalizing Psychopathology as a Multivariate Psychophysiological Phenotype

    Science.gov (United States)

    Nelson, Lindsay D.; Patrick, Christopher J.; Bernat, Edward M.

    2010-01-01

    The externalizing dimension is viewed as a broad dispositional factor underlying risk for numerous disinhibitory disorders. Prior work has documented deficits in event-related brain potential (ERP) responses in individuals prone to externalizing problems. Here, we constructed a direct physiological index of externalizing vulnerability from three ERP indicators and evaluated its validity in relation to criterion measures in two distinct domains: psychometric and physiological. The index was derived from three ERP measures that covaried in their relations with externalizing proneness the error-related negativity and two variants of the P3. Scores on this ERP composite predicted psychometric criterion variables and accounted for externalizing-related variance in P3 response from a separate task. These findings illustrate how a diagnostic construct can be operationalized as a composite (multivariate) psychophysiological variable (phenotype). PMID:20573054

  13. Simulation of weak and strong Langmuir collapse regimes

    International Nuclear Information System (INIS)

    Hadzievski, L.R.; Skoric, M.M.; Kono, M.; Sato, T.

    1998-01-01

    In order to check the validity of the self-similar solutions and the existence of weak and strong collapse regimes, direct two dimensional simulation of the time evolution of a Langmuir soliton instability is performed. Simulation is based on the Zakharov model of strong Langmuir turbulence in a weakly magnetized plasma accounting for the full ion dynamics. For parameters considered, agreement with self-similar dynamics of the weak collapse type is found with no evidence of the strong Langmuir collapse. (author)

  14. Electroweak processes in external active media

    CERN Document Server

    Kuznetsov, Alexander

    2013-01-01

    Expanding on the concept of the authors’ previous book “Electroweak Processes in External Electromagnetic Fields,” this new book systematically describes the investigation methods for the effects of external active media, both strong electromagnetic fields and hot dense plasma, in quantum processes. Solving the solar neutrino puzzle in a unique experiment conducted with the help of the heavy-water detector at the Sudbery Neutrino Observatory, along with another neutrino experiments, brings to the fore electroweak physics in an active external medium. It is effectively demonstrated that processes of neutrino interactions with active media of astrophysical objects may lead, under some physical conditions, to such interesting effects as neutrino-driven shockwave revival in a supernova explosion, a “cherry stone shooting” mechanism for pulsar natal kick, and a neutrino pulsar. It is also shown how poor estimates of particle dispersion in external active media sometimes lead to confusion. The book...

  15. Quantum electrodynamics of strong fields

    International Nuclear Information System (INIS)

    Greiner, W.

    1983-01-01

    Quantum Electrodynamics of Strong Fields provides a broad survey of the theoretical and experimental work accomplished, presenting papers by a group of international researchers who have made significant contributions to this developing area. Exploring the quantum theory of strong fields, the volume focuses on the phase transition to a charged vacuum in strong electric fields. The contributors also discuss such related topics as QED at short distances, precision tests of QED, nonperturbative QCD and confinement, pion condensation, and strong gravitational fields In addition, the volume features a historical paper on the roots of quantum field theory in the history of quantum physics by noted researcher Friedrich Hund

  16. Instabilities in strongly coupled plasmas

    CERN Document Server

    Kalman, G J

    2003-01-01

    The conventional Vlasov treatment of beam-plasma instabilities is inappropriate when the plasma is strongly coupled. In the strongly coupled liquid state, the strong correlations between the dust grains fundamentally affect the conditions for instability. In the crystalline state, the inherent anisotropy couples the longitudinal and transverse polarizations, and results in unstable excitations in both polarizations. We summarize analyses of resonant and non-resonant, as well as resistive instabilities. We consider both ion-dust streaming and dust beam-plasma instabilities. Strong coupling, in general, leads to an enhancement of the growth rates. In the crystalline phase, a resonant transverse instability can be excited.

  17. Bright branes for strongly coupled plasmas

    International Nuclear Information System (INIS)

    Mateos, David; Patino, Leonardo

    2007-01-01

    We use holographic techniques to study photon production in a class of finite temperature, strongly coupled, large-N c SU(N c ) quark-gluon plasmas with N f c quark flavours. Our results are valid to leading order in the electromagnetic coupling constant but non-perturbatively in the SU(N c ) interactions. The spectral function of electromagnetic currents and other related observables exhibit an interesting structure as a function of the photon frequency and the quark mass. We discuss possible implications for heavy ion collision experiments

  18. Circuit electromechanics with single photon strong coupling

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Zheng-Yuan, E-mail: zyxue@scnu.edu.cn; Yang, Li-Na [Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, and School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Zhou, Jian, E-mail: jianzhou8627@163.com [Department of Electronic Communication Engineering, Anhui Xinhua University, Hefei 230088 (China); Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, and School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China)

    2015-07-13

    In circuit electromechanics, the coupling strength is usually very small. Here, replacing the capacitor in circuit electromechanics by a superconducting flux qubit, we show that the coupling among the qubit and the two resonators can induce effective electromechanical coupling which can attain the strong coupling regime at the single photon level with feasible experimental parameters. We use dispersive couplings among two resonators and the qubit while the qubit is also driven by an external classical field. These couplings form a three-wave mixing configuration among the three elements where the qubit degree of freedom can be adiabatically eliminated, and thus results in the enhanced coupling between the two resonators. Therefore, our work constitutes the first step towards studying quantum nonlinear effect in circuit electromechanics.

  19. Strong ground motion prediction using virtual earthquakes.

    Science.gov (United States)

    Denolle, M A; Dunham, E M; Prieto, G A; Beroza, G C

    2014-01-24

    Sedimentary basins increase the damaging effects of earthquakes by trapping and amplifying seismic waves. Simulations of seismic wave propagation in sedimentary basins capture this effect; however, there exists no method to validate these results for earthquakes that have not yet occurred. We present a new approach for ground motion prediction that uses the ambient seismic field. We apply our method to a suite of magnitude 7 scenario earthquakes on the southern San Andreas fault and compare our ground motion predictions with simulations. Both methods find strong amplification and coupling of source and structure effects, but they predict substantially different shaking patterns across the Los Angeles Basin. The virtual earthquake approach provides a new approach for predicting long-period strong ground motion.

  20. Short proofs of strong normalization

    OpenAIRE

    Wojdyga, Aleksander

    2008-01-01

    This paper presents simple, syntactic strong normalization proofs for the simply-typed lambda-calculus and the polymorphic lambda-calculus (system F) with the full set of logical connectives, and all the permutative reductions. The normalization proofs use translations of terms and types to systems, for which strong normalization property is known.

  1. Strong-back safety latch

    International Nuclear Information System (INIS)

    DeSantis, G.N.

    1995-01-01

    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch

  2. Patterns of strong coupling for LHC searches

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Da [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics,Chinese Academy of Sciences, Beijing, People’s Republic of (China); Theoretical Particle Physics Laboratory, Institute of Physics,EPFL, CH-1015 Lausanne (Switzerland); Pomarol, Alex [CERN, Theoretical Physics Department,1211 Geneva 23 (Switzerland); Dept. de Física and IFAE-BIST,Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Rattazzi, Riccardo [Theoretical Particle Physics Laboratory, Institute of Physics,EPFL, CH-1015 Lausanne (Switzerland); Riva, Francesco [CERN, Theoretical Physics Department,1211 Geneva 23 (Switzerland)

    2016-11-23

    Even though the Standard Model (SM) is weakly coupled at the Fermi scale, a new strong dynamics involving its degrees of freedom may conceivably lurk at slightly higher energies, in the multi TeV range. Approximate symmetries provide a structurally robust context where, within the low energy description, the dimensionless SM couplings are weak, while the new strong dynamics manifests itself exclusively through higher-derivative interactions. We present an exhaustive classification of such scenarios in the form of effective field theories, paying special attention to new classes of models where the strong dynamics involves, along with the Higgs boson, the SM gauge bosons and/or the fermions. The IR softness of the new dynamics suppresses its effects at LEP energies, but deviations are in principle detectable at the LHC, even at energies below the threshold for production of new states. We believe our construction provides the so far unique structurally robust context where to motivate several LHC searches in Higgs physics, diboson production, or WW scattering. Perhaps surprisingly, the interplay between weak coupling, strong coupling and derivatives, which is controlled by symmetries, can override the naive expansion in operator dimension, providing instances where dimension-8 dominates dimension-6, well within the domain of validity of the low energy effective theory. This result reveals the limitations of an analysis that is both ambitiously general and restricted to dimension-6 operators.

  3. Strongly nonlinear evolution of low-frequency wave packets in a dispersive plasma

    Science.gov (United States)

    Vasquez, Bernard J.

    1993-01-01

    The evolution of strongly nonlinear, strongly modulated wave packets is investigated in a dispersive plasma using a hybrid numerical code. These wave packets have amplitudes exceeding the strength of the external magnetic field, along which they propagate. Alfven (left helicity) wave packets show strong steepening for p Schrodinger (DNLS) equation.

  4. The ExternE project: methodology, objectives and limitations

    International Nuclear Information System (INIS)

    Rabl, A.; Spadaro, J.V.

    2002-01-01

    This paper presents a summary of recent studies on external costs of energy systems, in particular the ExternE (External Costs of Energy) Project of the European Commission. To evaluate the impact and damage cost of a pollutant, one needs to carry out an impact pathway analysis; this involves the calculation of increased pollutant concentrations in all affected regions due to an incremental emission (e.g. μg/m 3 of particles, using models of atmospheric dispersion and chemistry), followed by the calculation of physical impacts (e.g. number of cases of asthma due to these particles, using a dose-response function). The entire so-called fuel chain (or fuel cycle) is evaluated and compared on the basis of delivered end use energy. Even though the uncertainties are large, the results provide substantial evidence that the classical air pollutants (particles, NO x and SO x ) from the combustion of fossil fuels impose a heavy toll, in addition to the cost of global warming. The external costs are especially large for coal; even for 'good current technology' they may be comparable to the price of electricity. For natural gas the external costs are about a third to a half of coal. The external costs of nuclear are small compared to the price of electricity (at most a few %), and so are the external costs of most renewable energy systems. (authors)

  5. External coating of colonic anastomoses

    DEFF Research Database (Denmark)

    Pommergaard, Hans-Christian; Achiam, Michael Patrick; Rosenberg, Jacob

    2012-01-01

    Colon anastomotic leakage remains both a frequent and serious complication in gastrointestinal surgery. External coating of colonic anastomoses has been proposed as a means to lower the rate of this complication. The aim of this review was to evaluate existing studies on external coating of colonic...

  6. Retrofitting Systems for External Walls

    DEFF Research Database (Denmark)

    Rose, Jørgen

    1997-01-01

    In this report, 9 different external and internal retrofitting systems are analyzed using numerical calculations. The analysis focuses on the thermal bridge effects in the different systems, and on this basis it is discussed whether internal or external retrofitting has the most advantages...

  7. Performance Targets and External Benchmarking

    DEFF Research Database (Denmark)

    Friis, Ivar; Hansen, Allan; Vámosi, Tamás S.

    Research on relative performance measures, transfer pricing, beyond budgeting initiatives, target costing, piece rates systems and value based management has for decades underlined the importance of external benchmarking in performance management. Research conceptualises external benchmarking...... as a market mechanism that can be brought inside the firm to provide incentives for continuous improvement and the development of competitive advances. However, whereas extant research primarily has focused on the importance and effects of using external benchmarks, less attention has been directed towards...... the conditions upon which the market mechanism is performing within organizations. This paper aims to contribute to research by providing more insight to the conditions for the use of external benchmarking as an element in performance management in organizations. Our study explores a particular type of external...

  8. Malignant external otitis: CT evaluation

    International Nuclear Information System (INIS)

    Curtin, H.D.; Wolfe, P.; May, M.

    1982-01-01

    Malignant external otitis is an aggressive infection caused by Pseudomonas aeruginosa that most often occurs in elderly diabetics. Malignant external otitis often spreads inferiorly from the external canal to involve the subtemporal area and progresses medially towards the petrous apex leading to multiple cranial nerve palsies. The computed tomographic (CT) findings in malignant external otitis include obliteration of the normal fat planes in the subtemporal area as well as patchy destruction of the bony cortex of the mastoid. The point of exit of the various cranial nerves can be identified on CT scans, and the extent of the inflammatory mass correlates well with the clinical findings. Four cases of malignant external otitis are presented. In each case CT provided a good demonstration of involvement of the soft tissues at the base of the skull

  9. Prediction models for successful external cephalic version: a systematic review.

    Science.gov (United States)

    Velzel, Joost; de Hundt, Marcella; Mulder, Frederique M; Molkenboer, Jan F M; Van der Post, Joris A M; Mol, Ben W; Kok, Marjolein

    2015-12-01

    To provide an overview of existing prediction models for successful ECV, and to assess their quality, development and performance. We searched MEDLINE, EMBASE and the Cochrane Library to identify all articles reporting on prediction models for successful ECV published from inception to January 2015. We extracted information on study design, sample size, model-building strategies and validation. We evaluated the phases of model development and summarized their performance in terms of discrimination, calibration and clinical usefulness. We collected different predictor variables together with their defined significance, in order to identify important predictor variables for successful ECV. We identified eight articles reporting on seven prediction models. All models were subjected to internal validation. Only one model was also validated in an external cohort. Two prediction models had a low overall risk of bias, of which only one showed promising predictive performance at internal validation. This model also completed the phase of external validation. For none of the models their impact on clinical practice was evaluated. The most important predictor variables for successful ECV described in the selected articles were parity, placental location, breech engagement and the fetal head being palpable. One model was assessed using discrimination and calibration using internal (AUC 0.71) and external validation (AUC 0.64), while two other models were assessed with discrimination and calibration, respectively. We found one prediction model for breech presentation that was validated in an external cohort and had acceptable predictive performance. This model should be used to council women considering ECV. Copyright © 2015. Published by Elsevier Ireland Ltd.

  10. Testing the role of external debt in environmental degradation: empirical evidence from Turkey.

    Science.gov (United States)

    Katircioglu, Salih; Celebi, Aysem

    2018-03-01

    This study investigates the role of external debt stock in Turkey, which has suffered from heavy (external and domestic) debt stock for many years. Annual data from 1960 to 2013 was analyzed using time series analysis in order to study this. The results confirm the validity of the conventional environmental Kuznets curve (EKC) in the case of Turkey. However, this study also found that Turkey's external debt stock did not influence the Turkish economy's long-term EKC behavior. Fortunately, the results suggest that there are important interactions among external debt stock, CO 2 emissions, energy consumption, and real income; that is, changes in external debt volume precede changes in these aggregates' volumes.

  11. FACTAR validation

    International Nuclear Information System (INIS)

    Middleton, P.B.; Wadsworth, S.L.; Rock, R.C.; Sills, H.E.; Langman, V.J.

    1995-01-01

    A detailed strategy to validate fuel channel thermal mechanical behaviour codes for use of current power reactor safety analysis is presented. The strategy is derived from a validation process that has been recently adopted industry wide. Focus of the discussion is on the validation plan for a code, FACTAR, for application in assessing fuel channel integrity safety concerns during a large break loss of coolant accident (LOCA). (author)

  12. Strong coupling phase in QED

    International Nuclear Information System (INIS)

    Aoki, Ken-ichi

    1988-01-01

    Existence of a strong coupling phase in QED has been suggested in solutions of the Schwinger-Dyson equation and in Monte Carlo simulation of lattice QED. In this article we recapitulate the previous arguments, and formulate the problem in the modern framework of the renormalization theory, Wilsonian renormalization. This scheme of renormalization gives the best understanding of the basic structure of a field theory especially when it has a multi-phase structure. We resolve some misleading arguments in the previous literature. Then we set up a strategy to attack the strong phase, if any. We describe a trial; a coupled Schwinger-Dyson equation. Possible picture of the strong coupling phase QED is presented. (author)

  13. External costs related to power production technologies. ExternE national implementation for Denmark

    International Nuclear Information System (INIS)

    Schleisner, L.; Sieverts Nielsen, P.

    1997-12-01

    The objective of the ExternE National Implementation project has been to establish a comprehensive and comparable set of data on externalities of power generation for all EU member states and Norway. The tasks include the application of the ExternE methodology to the most important fuel cycles for each country as well as to update the already existing results; to aggregate these site- and technology-specific results to more general figures. The current report covers the results of the national implementation for Denmark. Three different fuel cycles have been chosen as case studies. These are fuel cycles for an offshore wind farm and a wind farm on land, a decentralised CHP plant based on natural gas and a decentralised CHP plant based on biogas. The report covers all the details of the application of the methodology to these fuel cycles aggregation to a national level. (au) EU-JOULE 3. 59 tabs., 25 ills., 61 refs

  14. External costs related to power production technologies. ExternE national implementation for Denmark

    Energy Technology Data Exchange (ETDEWEB)

    Schleisner, L; Sieverts Nielsen, P

    1997-12-01

    The objective of the ExternE National Implementation project has been to establish a comprehensive and comparable set of data on externalities of power generation for all EU member states and Norway. The tasks include the application of the ExternE methodology to the most important fuel cycles for each country as well as to update the already existing results; to aggregate these site- and technology-specific results to more general figures. The current report covers the results of the national implementation for Denmark. Three different fuel cycles have been chosen as case studies. These are fuel cycles for an offshore wind farm and a wind farm on land, a decentralised CHP plant based on natural gas and a decentralised CHP plant based on biogas. The report covers all the details of the application of the methodology to these fuel cycles aggregation to a national level. (au) EU-JOULE 3. 59 tabs., 25 ills., 61 refs.

  15. Strong interactions at high energy

    International Nuclear Information System (INIS)

    Anselmino, M.

    1995-01-01

    Spin effects in strong interaction high energy processes are subtle phenomena which involve both short and long distance physics and test perturbative and non perturbative aspects of QCD. Moreover, depending on quantities like interferences between different amplitudes and relative phases, spin observables always test a theory at a fundamental quantum mechanical level; it is then no surprise that spin data are often difficult to accommodate within the existing models. A report is made on the main issues and contributions discussed in the parallel Session on the open-quote open-quote Strong interactions at high energy close-quote close-quote in this Conference. copyright 1995 American Institute of Physics

  16. Strong-field dissociation dynamics

    International Nuclear Information System (INIS)

    DiMauro, L.F.; Yang, Baorui.

    1993-01-01

    The strong-field dissociation behavior of diatomic molecules is examined under two distinctive physical scenarios. In the first scenario, the dissociation of the isolated hydrogen and deuterium molecular ions is discussed. The dynamics of above-threshold dissociation (ATD) are investigated over a wide range of green and infrared intensities and compared to a dressed-state model. The second situation arises when strong-field neutral dissociation is followed by ionization of the atomic fragments. The study results in a direct measure of the atomic fragment's ac-Stark shift by observing the intensity-dependent shifts in the electron or nuclear fragment kinetic energy. 8 figs., 14 refs

  17. External effects in Swiss hydropower

    International Nuclear Information System (INIS)

    Hauenstein, W.; Bonvin, J.; Vouillamoz, J.

    1999-01-01

    The article discusses the external costs and benefits of hydropower that are not internalised in normal book-keeping. Several negative and positive effects are discussed. The results of a study that addressed the difficult task of quantifying these external effects are presented. An assessment of the results gained shows that difficulties are to be met regarding system limits, methods of expressing the effects in monetary terms and ethical factors. The report also examines the consideration of external effects as a correction factor for falsified market prices for electricity

  18. The SATISPSY-22: development and validation of a French hospitalized patients' satisfaction questionnaire in psychiatry.

    Science.gov (United States)

    Zendjidjian, X Y; Auquier, P; Lançon, C; Loundou, A; Parola, N; Faugère, M; Boyer, L

    2015-01-01

    The aim of our study was to develop a specific French self-administered instrument for measuring hospitalized patients' satisfaction in psychiatry based on exclusive patient point of view: the SATISPSY-22. The development of the SATISPSY was undertaken in three steps: item generation, item reduction, and validation. The content of the SATISPSY was derived from 80 interviews with patients hospitalized in psychiatry. Using item response and classical test theories, item reduction was performed in 2 hospitals on 270 responders. The validation was based on construct validity, reliability, and some aspects of external validity. The SATISPSY contains 22 items describing 6 dimensions (staff, quality of care, personal experience, information, activity, and food). The six-factor structure accounted for 78.0% of the total variance. Each item achieved the 0.40 standard for item-internal consistency, and the Cronbach's alpha coefficients were>0.70. Scores of dimensions were strongly positively correlated with Visual Analogue Scale scores. Significant associations with socioeconomic and clinical indicators showed good discriminant and external validity. INFIT statistics were ranged from 0.71 to 1.25. The SATISPSY-22 presents satisfactory psychometric properties, enabling patient feedback to be incorporated in a continuous quality health care improvement strategy. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  19. Strong Decomposition of Random Variables

    DEFF Research Database (Denmark)

    Hoffmann-Jørgensen, Jørgen; Kagan, Abram M.; Pitt, Loren D.

    2007-01-01

    A random variable X is stongly decomposable if X=Y+Z where Y=Φ(X) and Z=X-Φ(X) are independent non-degenerated random variables (called the components). It is shown that at least one of the components is singular, and we derive a necessary and sufficient condition for strong decomposability...... of a discrete random variable....

  20. Strong coupling electroweak symmetry breaking

    International Nuclear Information System (INIS)

    Barklow, T.L.; Burdman, G.; Chivukula, R.S.

    1997-04-01

    The authors review models of electroweak symmetry breaking due to new strong interactions at the TeV energy scale and discuss the prospects for their experimental tests. They emphasize the direct observation of the new interactions through high-energy scattering of vector bosons. They also discuss indirect probes of the new interactions and exotic particles predicted by specific theoretical models

  1. Strong coupling electroweak symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Barklow, T.L. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Burdman, G. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Physics; Chivukula, R.S. [Boston Univ., MA (United States). Dept. of Physics

    1997-04-01

    The authors review models of electroweak symmetry breaking due to new strong interactions at the TeV energy scale and discuss the prospects for their experimental tests. They emphasize the direct observation of the new interactions through high-energy scattering of vector bosons. They also discuss indirect probes of the new interactions and exotic particles predicted by specific theoretical models.

  2. The colours of strong interaction

    International Nuclear Information System (INIS)

    1995-01-01

    The aim of this session is to draw a consistent framework about the different ways to consider strong interaction. A large part is dedicated to theoretical work and the latest experimental results obtained at the first electron collider HERA are discussed. (A.C.)

  3. Resonance double magnetic bremsstrahlung in a strong magnetic field

    International Nuclear Information System (INIS)

    Fomin, P.I.; Kholodov, R.I.

    2003-01-01

    The possibility of resonance double magnetic bremsstrahlung in the approximation of weakly excited electron states in a strong external magnetic field is analyzed. The differential probability of this process in the Breit-Wigner form is obtained. The probability of double magnetic bremsstrahlung (second-order process of perturbation theory) is compared with the probability of magnetic bremsstrahlung (first-order process of perturbation theory)

  4. Induced photoassociation in the field of a strong electomagnetic wave

    International Nuclear Information System (INIS)

    Zaretskij, D.F.; Lomonosov, V.V.; Lyul'ka, V.A.

    1979-01-01

    The quantum-mechanical problem of the stimulated transition of a system in the field of a strong electromagnetic wave from the continuous spectrum to a bound state possessing a finite lifetime is considered. The expressions obtained are employed to calculate stimulated production of mesic atoms and mesic molecules (ddμ). It is demonstrated that in an external electromagnetic field the probability for production of this type may considerably increase

  5. Introducing external cephalic version in a Malaysian setting.

    Science.gov (United States)

    Yong, Stephen P Y

    2007-02-01

    To assess the outcome of external cephalic version for routine management of malpresenting foetuses at term. Prospective observational study. Tertiary teaching hospital, Malaysia. From September 2003 to June 2004, a study involving 41 pregnant women with malpresentation at term was undertaken. An external cephalic version protocol was implemented. Data were collected for identifying characteristics associated with success or failure of external cephalic version. Maternal and foetal outcome measures including success rate of external cephalic version, maternal and foetal complications, and characteristics associated with success or failure; engagement of presenting part, placental location, direction of version, attempts at version, use of intravenous tocolytic agent, eventual mode of delivery, Apgar scores, birth weights, and maternal satisfaction with the procedure. Data were available for 38 women. External cephalic version was successful in 63% of patients; the majority (75%) of whom achieved a vaginal delivery. Multiparity (odds ratio=34.0; 95% confidence interval, 0.67-1730) and high amniotic fluid index (4.9; 1.3-18.2) were associated with successful external cephalic version. Engagement of presenting part (odds ratio=0.0001; 95% confidence interval, 0.00001-0.001) and a need to resort to backward somersault (0.02; 0.00001-0.916) were associated with poor success rates. Emergency caesarean section rate for foetal distress directly resulting from external cephalic version was 8%, but there was no perinatal or maternal adverse outcome. The majority (74%) of women were satisfied with external cephalic version. External cephalic version has acceptable success rates. Multiparity, liquor volume, engagement of presenting part, and the need for backward somersault were strong predictors of outcome. External cephalic version is relatively safe, simple to learn and perform, and associated with maternal satisfaction. Modern obstetric units should routinely offer the

  6. Perturbation Solutions of the Quintic Duffing Equation with Strong Nonlinearities

    Directory of Open Access Journals (Sweden)

    Mehmet Pakdemirli

    Full Text Available The quintic Duffing equation with strong nonlinearities is considered. Perturbation solutions are constructed using two different techniques: The classical multiple scales method (MS and the newly developed multiple scales Lindstedt Poincare method (MSLP. The validity criteria for admissible solutions are derived. Both approximate solutions are contrasted with the numerical solutions. It is found that MSLP provides compatible solution with the numerical solution for strong nonlinearities whereas MS solution fail to produce physically acceptable solution for large perturbation parameters.

  7. Control of external radiation exposure

    International Nuclear Information System (INIS)

    Abd Nasir Ibrahim; Azali Muhammad; Ab Razak Hamzah; Abd Aziz Mohamed; Mohammad Pauzi Ismail

    2004-01-01

    The following subjects are discussed - Control of external radiation exposure: working time, working distance, shielding: Total Linear Attenuation Coefficient, Half-Value Layer (HVL), Tenth-Value Layer (TVL); Build-up Factor

  8. Estimating parameters of chaotic systems synchronized by external driving signal

    International Nuclear Information System (INIS)

    Wu Xiaogang; Wang Zuxi

    2007-01-01

    Noise-induced synchronization (NIS) has evoked great research interests recently. Two uncoupled identical chaotic systems can achieve complete synchronization (CS) by feeding a common noise with appropriate intensity. Actually, NIS belongs to the category of external feedback control (EFC). The significance of applying EFC in secure communication lies in fact that the trajectory of chaotic systems is disturbed so strongly by external driving signal that phase space reconstruction attack fails. In this paper, however, we propose an approach that can accurately estimate the parameters of the chaotic systems synchronized by external driving signal through chaotic transmitted signal, driving signal and their derivatives. Numerical simulation indicates that this approach can estimate system parameters and external coupling strength under two driving modes in a very rapid manner, which implies that EFC is not superior to other methods in secure communication

  9. External costs related to power production technologies. ExternE national implementation for Denmark

    International Nuclear Information System (INIS)

    Schleisner, L.; Sieverts Nielsen, P.

    1997-12-01

    The objective of the ExternE National Implementation project has been to establish a comprehensive and comparable set of data on externalities of power generation for all EU member states and Norway. The tasks include the application of the ExternE methodology to the most important fuel cycles for each country as well as to update the already existing results, to aggregate these site- and technology-specific results to more general figures. The current report covers the detailed information concerning the ExternE methodology. Importance is attached to the computer system used in the project and the assessment of air pollution effects on health, materials and ecological effects. Also the assessment of global warming damages are described. Finally the report covers the detailed information concerning the national implementation for Denmark for an offshore wind farm and a wind farm on land, a decentralised CHP plant based on natural gas and a decentralised CHP plant base on biogas. (au) EU-JOULE 3. 79 tabs., 11 ills., 201 refs

  10. External costs related to power production technologies. ExternE national implementation for Denmark

    Energy Technology Data Exchange (ETDEWEB)

    Schleisner, L; Sieverts Nielsen, P [eds.

    1997-12-01

    The objective of the ExternE National Implementation project has been to establish a comprehensive and comparable set of data on externalities of power generation for all EU member states and Norway. The tasks include the application of the ExternE methodology to the most important fuel cycles for each country as well as to update the already existing results, to aggregate these site- and technology-specific results to more general figures. The current report covers the detailed information concerning the ExternE methodology. Importance is attached to the computer system used in the project and the assessment of air pollution effects on health, materials and ecological effects. Also the assessment of global warming damages are described. Finally the report covers the detailed information concerning the national implementation for Denmark for an offshore wind farm and a wind farm on land, a decentralised CHP plant based on natural gas and a decentralised CHP plant base on biogas. (au) EU-JOULE 3. 79 tabs., 11 ills., 201 refs.

  11. On the relationship between emotional and external eating behavior

    NARCIS (Netherlands)

    Van Strien, T; Schippers, G.M.; Cox, W M

    1995-01-01

    Although there is a strong relationship between emotional and external eating, separate subscales for these behaviors have been constructed in the Dutch Eating Behavior Questionnaire. This study tries to establish whether this distinction is justified. We studied relationships among self-reported (

  12. Fluxon interaction with external rf radiation in Josephson junctions

    DEFF Research Database (Denmark)

    Kivshar, Yuri S.; Olsen, Ole H.; Samuelsen, Mogens Rugholm

    1993-01-01

    . It is shown that due to excitation of a standing linear wave by the driving force, the fluxon motion is strongly influenced by a periodic (averaged) potential similar to the Peierls-Nabarro potential in a discrete chain. This effective potential decreases in the direction of the boundary where the external rf...

  13. Externalities of energy. Swedish implementation of the ExternE methodology

    International Nuclear Information System (INIS)

    Nilsson, Maans; Gullberg, M.

    1998-01-01

    The growing interest for developing economic instruments for efficient environmental policies has opened up a large area of multi-disciplinary research. ExternE is an example of this research, combining disciplines such as engineering, ecology, immunology and economics expertise to create new knowledge about how environmental pressures from energy production affect our nature and society. The ExternE Project aims to identify and, as far as possible quantify the externalities of energy production in Europe. The Stockholm Environment Institute has carried out a preliminary aggregation: -Coal Fuel Cycle: centred around Vaesteraas Kraftvaermeverk, Vaesteraas. This is the largest co-generation plant in Sweden, with four blocks and a maximum co-generation output of 520 MW electricity and 950 MW heat. The analysis is carried out on boiler B4. -Biomass Fuel Cycle: centred around Haendeloeverket, Norrkoeping. This plant predominately burns forestry residues, but a variety of fuels are combusted. Haendeloeverket has an installed capacity of 100 MW electricity and 375 MW heat, in a total of three boilers and two back-pressure turbines. The analysis is carried out on boiler P13. -Hydro Fuel Cycle: Klippens Kraftstation, Storuman. Built in 1990-1994, it is the youngest hydro power station in Sweden. It has been designed and built with significant efforts to account for and protect environmental values. Installed capacity is 28 MW. The environmental impact assessment from the construction of this plant is carried out, but the evaluation is still not finalized. The preliminary aggregation aimed to test whether ExternE results could be used to make estimates for the entire Swedish electricity production system. Hence, national results as well as results from other partner countries in ExternE has been applied

  14. Urban Sprawl and Transportation Externalities

    OpenAIRE

    Holcombe, Randall G.; Williams, DeEdgra W.

    2010-01-01

    One argument in support of minimizing urban sprawl is that sprawl creates transportation externalities. A problem with empirically examining the relationship between sprawl and transportation externalities is that sprawl is a difficult concept to quantify. This paper uses a measure of sprawl designed by Ewing, Pendall, and Chen (2002) to examine the relationship between sprawl and commute times, automobile ownership, miles driven, fatal auto accidents, air pollution, and highway expenditures....

  15. Conceptual challenges for internalising externalities

    DEFF Research Database (Denmark)

    Miguel, Brandão; Weidema, Bo Pedersen

    2013-01-01

    We analyse a number of different externalities to identify conceptual challenges for the practical implementation of their internalisation. Three issues were identified: i) The balance between compensation and technology change and the respective effects on the nominal and real GDP; ii...... geographical and especially temporal distance between the benefitting actor and the victim of the external cost, the involvement of a non-governmental intermediate actor becomes increasingly necessary to provide the short-term capital required to ensure a successful implementation....

  16. Parallel External Memory Graph Algorithms

    DEFF Research Database (Denmark)

    Arge, Lars Allan; Goodrich, Michael T.; Sitchinava, Nodari

    2010-01-01

    In this paper, we study parallel I/O efficient graph algorithms in the Parallel External Memory (PEM) model, one o f the private-cache chip multiprocessor (CMP) models. We study the fundamental problem of list ranking which leads to efficient solutions to problems on trees, such as computing lowest...... an optimal speedup of ¿(P) in parallel I/O complexity and parallel computation time, compared to the single-processor external memory counterparts....

  17. Internal hiring or external recruitment?

    OpenAIRE

    DeVaro, Jed

    2016-01-01

    Hiring is one of a firm’s most important decisions. When an employer fills a vacancy with one of its own workers (through promotion or lateral transfer), it forgoes the opportunity to fill the position with a new hire from outside the firm. Although both internal and external hiring methods are used, firms frequently have a bias favoring insiders. Internal and external hires differ in observable characteristics (such as skill levels), as do the employers making each type of hiring decision. U...

  18. The Impact of Recipient Site External Expansion in Fat Grafting Surgical Outcomes

    Directory of Open Access Journals (Sweden)

    Carlo M. Oranges, MD

    2018-02-01

    Conclusions:. External expansion and fat grafting is a promising technique for breast reconstruction and augmentation. However, due to the overall low level of evidence of the available studies, further research is needed to validate the procedure.

  19. Adaptation and Validation of the Psychological Need Thwarting Scale in Spanish Physical Education Teachers.

    Science.gov (United States)

    Cuevas, Ricardo; Sánchez-Oliva, David; Bartholomew, Kimberley J; Ntoumanis, Nikos; García-Calvo, Tomás

    2015-07-20

    Drawing from self-determination theory (SDT; Deci & Ryan, 1985; Ryan & Deci, 2002), the aim of the study was to adapt and validate a Spanish version of the Psychological Need Thwarting Scale (PNTS; Bartholomew, Ntoumanis, Ryan, & Thørgersen-Ntoumani, 2011) in the educational domain. Psychological need thwarting and burnout were assessed in 619 physical education teachers from several high schools in Spain. Overall, the adapted measure demonstrated good content, factorial (χ2/gl = 4.87, p < .01, CFI = .95, IFI = .96, TLI = .94, RMSEA = .08, SRMR = .05), and external validity, as well as internal consistency (α ≥ .81) and invariance across gender. Moreover, burnout was strongly predicted by teachers' perceptions of competence (β = .53, p ≤ .01), autonomy (β = .34, p ≤ .01), and relatedness (β = .31, p ≤ .01) need thwarting. In conclusion, these results support the Spanish version of the PNTS as a valid and reliable instrument for assessing the understudied concept of psychological need thwarting in teachers.

  20. Strongly Correlated Systems Theoretical Methods

    CERN Document Server

    Avella, Adolfo

    2012-01-01

    The volume presents, for the very first time, an exhaustive collection of those modern theoretical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciates consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as po...

  1. Strongly correlated systems numerical methods

    CERN Document Server

    Mancini, Ferdinando

    2013-01-01

    This volume presents, for the very first time, an exhaustive collection of those modern numerical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and material science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciate consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as possi...

  2. Strongly correlated systems experimental techniques

    CERN Document Server

    Mancini, Ferdinando

    2015-01-01

    The continuous evolution and development of experimental techniques is at the basis of any fundamental achievement in modern physics. Strongly correlated systems (SCS), more than any other, need to be investigated through the greatest variety of experimental techniques in order to unveil and crosscheck the numerous and puzzling anomalous behaviors characterizing them. The study of SCS fostered the improvement of many old experimental techniques, but also the advent of many new ones just invented in order to analyze the complex behaviors of these systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. The volume presents a representative collection of the modern experimental techniques specifically tailored for the analysis of strongly correlated systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognize...

  3. Flavour Democracy in Strong Unification

    CERN Document Server

    Abel, S A; Abel, Steven; King, Steven

    1998-01-01

    We show that the fermion mass spectrum may naturally be understood in terms of flavour democratic fixed points in supersymmetric theories which have a large domain of attraction in the presence of "strong unification". Our approach provides an alternative to the approximate Yukawa texture zeroes of the Froggatt-Nielsen mechanism. We discuss a particular model based on a broken gauged $SU(3)_L\\times SU(3)_R$ family symmetry which illustrates our approach.

  4. String dynamics at strong coupling

    International Nuclear Information System (INIS)

    Hull, C.M.

    1996-01-01

    The dynamics of superstring, supergravity and M-theories and their compactifications are probed by studying the various perturbation theories that emerge in the strong and weak-coupling limits for various directions in coupling constant space. The results support the picture of an underlying non-perturbative theory that, when expanded perturbatively in different coupling constants, gives different perturbation theories, which can be perturbative superstring theories or superparticle theories. The p-brane spectrum is considered in detail and a criterion found to establish which p-branes govern the strong-coupling dynamics. In many cases there are competing conjectures in the literature, and this analysis decides between them. In other cases, new results are found. The chiral 6-dimensional theory resulting from compactifying the type IIB string on K 3 is studied in detail and it is found that certain strong-coupling limits appear to give new theories, some of which hint at the possibility of a 12-dimensional origin. (orig.)

  5. Translation and validation of the German version of the Bournemouth Questionnaire for Neck Pain

    Directory of Open Access Journals (Sweden)

    Soklic Marina

    2012-01-01

    Full Text Available Abstract Background Clinical outcome measures are important tools to monitor patient improvement during treatment as well as to document changes for research purposes. The short-form Bournemouth questionnaire for neck pain patients (BQN was developed from the biopsychosocial model and measures pain, disability, cognitive and affective domains. It has been shown to be a valid and reliable outcome measure in English, French and Dutch and more sensitive to change compared to other questionnaires. The purpose of this study was to translate and validate a German version of the Bournemouth questionnaire for neck pain patients. Methods German translation and back translation into English of the BQN was done independently by four persons and overseen by an expert committee. Face validity of the German BQN was tested on 30 neck pain patients in a single chiropractic practice. Test-retest reliability was evaluated on 31 medical students and chiropractors before and after a lecture. The German BQN was then assessed on 102 first time neck pain patients at two chiropractic practices for internal consistency, external construct validity, external longitudinal construct validity and sensitivity to change compared to the German versions of the Neck Disability Index (NDI and the Neck Pain and Disability Scale (NPAD. Results Face validity testing lead to minor changes to the German BQN. The Intraclass Correlation Coefficient for the test-retest reliability was 0.99. The internal consistency was strong for all 7 items of the BQN with Cronbach α's of .79 and .80 for the pre and post-treatment total scores. External construct validity and external longitudinal construct validity using Pearson's correlation coefficient showed statistically significant correlations for all 7 scales of the BQN with the other questionnaires. The German BQN showed greater responsiveness compared to the other questionnaires for all scales. Conclusions The German BQN is a valid and

  6. External Correlates of the MMPI-2 Content Component Scales in Mental Health Inpatients

    Science.gov (United States)

    Green, Bradley A.; Handel, Richard W.; Archer, Robert P.

    2006-01-01

    External correlates of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) Content Component Scales were identified using an inpatient sample of 544 adults. The Brief Psychiatric Rating Scale (BPRS) and Symptom Checklist 90-Revised (SCL-90-R) produced correlates of the Content Component Scales, demonstrating external validity with…

  7. Approaches in estimation of external cost for fuel cycles in the ExternE project

    International Nuclear Information System (INIS)

    Afanas'ev, A.A.; Maksimenko, B.N.

    1998-01-01

    The purposes, content and main results of studies realized within the frameworks of the International Project ExternE which is the first comprehensive attempt to develop general approach to estimation of external cost for different fuel cycles based on utilization of nuclear and fossil fuels, as well as on renewable power sources are discussed. The external cost of a fuel cycle is treated as social and environmental expenditures which are not taken into account by energy producers and consumers, i.e. these are expenditures not included into commercial cost nowadays. The conclusion on applicability of the approach suggested for estimation of population health hazards and environmental impacts connected with electric power generation growth (expressed in money or some other form) is made

  8. Towards TDDFT for Strongly Correlated Materials

    Directory of Open Access Journals (Sweden)

    Shree Ram Acharya

    2016-09-01

    Full Text Available We present some details of our recently-proposed Time-Dependent Density-Functional Theory (TDDFT for strongly-correlated materials in which the exchange-correlation (XC kernel is derived from the charge susceptibility obtained using Dynamical Mean-Field Theory (the TDDFT + DMFT approach. We proceed with deriving the expression for the XC kernel for the one-band Hubbard model by solving DMFT equations via two approaches, the Hirsch–Fye Quantum Monte Carlo (HF-QMC and an approximate low-cost perturbation theory approach, and demonstrate that the latter gives results that are comparable to the exact HF-QMC solution. Furthermore, through a variety of applications, we propose a simple analytical formula for the XC kernel. Additionally, we use the exact and approximate kernels to examine the nonhomogeneous ultrafast response of two systems: a one-band Hubbard model and a Mott insulator YTiO3. We show that the frequency dependence of the kernel, i.e., memory effects, is important for dynamics at the femtosecond timescale. We also conclude that strong correlations lead to the presence of beats in the time-dependent electric conductivity in YTiO3, a feature that could be tested experimentally and that could help validate the few approximations used in our formulation. We conclude by proposing an algorithm for the generalization of the theory to non-linear response.

  9. Impact of external conditions on energy consumption in industrial halls

    Science.gov (United States)

    Żabnieńśka-Góra, Alina

    2017-11-01

    The energy demand for heating the halls buildings is high. The impact on this may have the technology of production, building construction and technology requirements (HVAC systems). The isolation of the external partitions, the location of the object in relation to the surrounding buildings and the degree of the interior insolation (windows and skylights) are important in the context of energy consumption. The article discusses the impact of external conditions, wind and sunlight on energy demand in the industrial hall. The building model was prepared in IDA ICE 4.0 simulation software. Model validation was done based on measurements taken in the analyzed building.

  10. Strongly nonlinear dynamics of electrolytes in large ac voltages

    DEFF Research Database (Denmark)

    Olesen, Laurits Højgaard; Bazant, Martin Z.; Bruus, Henrik

    2010-01-01

    to suppress the strongly nonlinear regime in the limit of concentrated electrolytes, ionic liquids, and molten salts. Beyond the model problem, our reduced equations for thin double layers, based on uniformly valid matched asymptotic expansions, provide a useful mathematical framework to describe additional...

  11. Theory of Spin Waves in Strongly Anisotropic Magnets

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker; Cooke, J. F.

    1976-01-01

    A new infinite-order perturbation approach to the theory of spin waves in strongly anisotropic magnets is introduced. The system is transformed into one with effective two-ion anisotropy and considerably reduced ground-state corrections. A general expression for the spin-wave energy, valid to any...

  12. PREFACE: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Saxena, Siddharth S.; Littlewood, P. B.

    2012-07-01

    This special section is dedicated to the Strongly Correlated Electron Systems Conference (SCES) 2011, which was held from 29 August-3 September 2011, in Cambridge, UK. SCES'2011 is dedicated to 100 years of superconductivity and covers a range of topics in the area of strongly correlated systems. The correlated electronic and magnetic materials featured include f-electron based heavy fermion intermetallics and d-electron based transition metal compounds. The selected papers derived from invited presentations seek to deepen our understanding of the rich physical phenomena that arise from correlation effects. The focus is on quantum phase transitions, non-Fermi liquid phenomena, quantum magnetism, unconventional superconductivity and metal-insulator transitions. Both experimental and theoretical work is presented. Based on fundamental advances in the understanding of electronic materials, much of 20th century materials physics was driven by miniaturisation and integration in the electronics industry to the current generation of nanometre scale devices. The achievements of this industry have brought unprecedented advances to society and well-being, and no doubt there is much further to go—note that this progress is founded on investments and studies in the fundamentals of condensed matter physics from more than 50 years ago. Nevertheless, the defining challenges for the 21st century will lie in the discovery in science, and deployment through engineering, of technologies that can deliver the scale needed to have an impact on the sustainability agenda. Thus the big developments in nanotechnology may lie not in the pursuit of yet smaller transistors, but in the design of new structures that can revolutionise the performance of solar cells, batteries, fuel cells, light-weight structural materials, refrigeration, water purification, etc. The science presented in the papers of this special section also highlights the underlying interest in energy-dense materials, which

  13. Atoms in strong laser fields

    International Nuclear Information System (INIS)

    L'Huillier, A.

    2002-01-01

    When a high-power laser focuses into a gas of atoms, the electromagnetic field becomes of the same magnitude as the Coulomb field which binds a 1s electron in a hydrogen atom. 3 highly non-linear phenomena can happen: 1) ATI (above threshold ionization): electrons initially in the ground state absorb a large number of photons, many more than the minimum number required for ionization; 2) multiple ionization: many electrons can be emitted one at a time, in a sequential process, or simultaneously in a mechanism called direct or non-sequential; and 3) high order harmonic generation (HHG): efficient photon emission in the extreme ultraviolet range, in the form of high-order harmonics of the fundamental laser field can occur. The theoretical problem consists in solving the time dependent Schroedinger equation (TDSE) that describes the interaction of a many-electron atom with a laser field. A number of methods have been proposed to solve this problem in the case of a hydrogen atom or a single-active electron atom in a strong laser field. A large effort is presently being devoted to go beyond the single-active approximation. The understanding of the physics of the interaction between atoms and strong laser fields has been provided by a very simple model called ''simple man's theory''. A unified view of HHG, ATI, and non-sequential ionization, originating from the simple man's model and the strong field approximation, expressed in terms of electrons trajectories or quantum paths is slowly emerging. (A.C.)

  14. Strong versions of Bell's theorem

    International Nuclear Information System (INIS)

    Stapp, H.P.

    1994-01-01

    Technical aspects of a recently constructed strong version of Bell's theorem are discussed. The theorem assumes neither hidden variables nor factorization, and neither determinism nor counterfactual definiteness. It deals directly with logical connections. Hence its relationship with modal logic needs to be described. It is shown that the proof can be embedded in an orthodox modal logic, and hence its compatibility with modal logic assured, but that this embedding weakens the theorem by introducing as added assumptions the conventionalities of the particular modal logic that is adopted. This weakening is avoided in the recent proof by using directly the set-theoretic conditions entailed by the locality assumption

  15. Strongly interacting light dark matter

    International Nuclear Information System (INIS)

    Bruggisser, Sebastian; Riva, Francesco; Urbano, Alfredo

    2016-07-01

    In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM) can appear weakly coupled at small-energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo-Nambu-Goldstone Bosons and Goldstini) are interesting targets for LHC missing-energy searches.

  16. Weak consistency and strong paraconsistency

    Directory of Open Access Journals (Sweden)

    Gemma Robles

    2009-11-01

    Full Text Available In a standard sense, consistency and paraconsistency are understood as, respectively, the absence of any contradiction and as the absence of the ECQ (“E contradictione quodlibet” rule that allows us to conclude any well formed formula from any contradiction. The aim of this paper is to explain the concepts of weak consistency alternative to the standard one, the concepts of paraconsistency related to them and the concept of strong paraconsistency, all of which have been defined by the author together with José M. Méndez.

  17. On the strong CP problem

    Energy Technology Data Exchange (ETDEWEB)

    Dowrick, N.J. (Dept. of Physics, Oxford (United Kingdom)); McDougall, N.A. (National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan))

    1992-07-09

    We show that two well-known solutions to the strong CP problem, the axion and a massless quark, may be understood in terms of the mechanism recently proposed by Samuel where long-range interactions between topological charges may be responsible for the removal of CP violation. We explain how the axion and a QCD meson (identified as the {eta}' if all quarks are massless) suppress fluctuations in global topological charge by almost identical dynamical although the masses, couplings and relevant length scales are very different. Furthermore, we elucidate the precise origin of the {eta}' mass. (orig.).

  18. Scalar strong interaction hadron theory

    CERN Document Server

    Hoh, Fang Chao

    2015-01-01

    The scalar strong interaction hadron theory, SSI, is a first principles' and nonlocal theory at quantum mechanical level that provides an alternative to low energy QCD and Higgs related part of the standard model. The quark-quark interaction is scalar rather than color-vectorial. A set of equations of motion for mesons and another set for baryons have been constructed. This book provides an account of the present state of a theory supposedly still at its early stage of development. This work will facilitate researchers interested in entering into this field and serve as a basis for possible future development of this theory.

  19. Estimation of strong ground motion

    International Nuclear Information System (INIS)

    Watabe, Makoto

    1993-01-01

    Fault model has been developed to estimate a strong ground motion in consideration of characteristics of seismic source and propagation path of seismic waves. There are two different approaches in the model. The first one is a theoretical approach, while the second approach is a semi-empirical approach. Though the latter is more practical than the former to be applied to the estimation of input motions, it needs at least the small-event records, the value of the seismic moment of the small event and the fault model of the large event

  20. Strong Mechanoluminescence from Oxynitridosilicate Phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lin; Xu Chaonan; Yamada, Hiroshi, E-mail: cn-xu@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), 807-1 Shuku, Tosu, Saga 841-0052 (Japan)

    2011-10-29

    We successfully developed a novel Mechanoluminescence (ML) material with water resistance, oxynitridosilicate; BaSi{sub 2}O{sub 2}N{sub 2}: Eu{sup 2+}. The crystal structure, photoluminescence (PL) and ML properties were characterized. The ML of BaSi{sub 2}O{sub 2}N{sub 2}: Eu{sup 2+} is so strong that the blue-green emission can be observed by the naked eyes clearly. In addition, it shows superior water resistance property. No changes were found in the ML intensities during the total water treatment test.

  1. Construct Validity of the MMPI-2-RF Triarchic Psychopathy Scales in Correctional and Collegiate Samples.

    Science.gov (United States)

    Kutchen, Taylor J; Wygant, Dustin B; Tylicki, Jessica L; Dieter, Amy M; Veltri, Carlo O C; Sellbom, Martin

    2017-01-01

    This study examined the MMPI-2-RF (Ben-Porath & Tellegen, 2008/2011) Triarchic Psychopathy scales recently developed by Sellbom et al. ( 2016 ) in 3 separate groups of male correctional inmates and 2 college samples. Participants were administered a diverse battery of psychopathy specific measures (e.g., Psychopathy Checklist-Revised [Hare, 2003 ], Psychopathic Personality Inventory-Revised [Lilienfeld & Widows, 2005 ], Triarchic Psychopathy Measure [Patrick, 2010 ]), omnibus personality and psychopathology measures such as the Personality Assessment Inventory (Morey, 2007 ) and Personality Inventory for DSM-5 (Krueger, Derringer, Markon, Watson, & Skodol, 2012 ), and narrow-band measures that capture conceptually relevant constructs. Our results generally evidenced strong support for the convergent and discriminant validity for the MMPI-2-RF Triarchic scales. Boldness was largely associated with measures of fearless dominance, social potency, and stress immunity. Meanness showed strong relationships with measures of callousness, aggression, externalizing tendencies, and poor interpersonal functioning. Disinhibition exhibited strong associations with poor impulse control, stimulus seeking, and general externalizing proclivities. Our results provide additional construct validation to both the triarchic model and MMPI-2-RF Triarchic scales. Given the widespread use of the MMPI-2-RF in correctional and forensic settings, our results have important implications for clinical assessment in these 2 areas, where psychopathy is a highly relevant construct.

  2. Bursting pressure of autofrettaged cylinders with inclined external cracks

    International Nuclear Information System (INIS)

    Seifi, Rahman; Babalhavaeji, Majid

    2012-01-01

    Autofrettaging a pressure vessel improves its pressure capacity. This is reliable if there isn’t any crack or other type of flaws. In this paper, the effects of external surface cracks on bursting pressure of autofrettaged cylinders are studied. It is observed that bursting pressure decreases considerably (up to 30%) due to external cracks in the cylinders without autofrettage. This reduction increases for high levels of the applied autofrettage. External axial cracks have more effects than inclined cracks. Comparing experimental and numerical results show that the numerical methods can acceptably predict the bursting pressure of the autofrettaged cracked cylinders. These predictions are valid when the fracture parameter (J-Integral) is calculated from the modified equation that takes into account the effects of residual stresses. - Highlights: ► Modified J-Integral can be used for study of autofrettaged cracked cylinders. ► External axial cracks reduce considerably the pressure capacity of cylinders. ► External circumferential cracks have not considerable effects on bursting pressure. ► Autofrettage has contrary effects on external crack in compared with internal crack.

  3. Bursting pressure of autofrettaged cylinders with inclined external cracks

    Energy Technology Data Exchange (ETDEWEB)

    Seifi, Rahman, E-mail: rseifi@basu.ac.ir [Mechanical Engineering Department, Faculty of Engineering, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of); Babalhavaeji, Majid [Mechanical Engineering Department, Faculty of Engineering, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of)

    2012-01-15

    Autofrettaging a pressure vessel improves its pressure capacity. This is reliable if there isn't any crack or other type of flaws. In this paper, the effects of external surface cracks on bursting pressure of autofrettaged cylinders are studied. It is observed that bursting pressure decreases considerably (up to 30%) due to external cracks in the cylinders without autofrettage. This reduction increases for high levels of the applied autofrettage. External axial cracks have more effects than inclined cracks. Comparing experimental and numerical results show that the numerical methods can acceptably predict the bursting pressure of the autofrettaged cracked cylinders. These predictions are valid when the fracture parameter (J-Integral) is calculated from the modified equation that takes into account the effects of residual stresses. - Highlights: Black-Right-Pointing-Pointer Modified J-Integral can be used for study of autofrettaged cracked cylinders. Black-Right-Pointing-Pointer External axial cracks reduce considerably the pressure capacity of cylinders. Black-Right-Pointing-Pointer External circumferential cracks have not considerable effects on bursting pressure. Black-Right-Pointing-Pointer Autofrettage has contrary effects on external crack in compared with internal crack.

  4. External circuit integration with electromagnetic particle in cell modeling of plasma focus devices

    International Nuclear Information System (INIS)

    Seng, Y. S.; Lee, P.; Rawat, R. S.

    2015-01-01

    The pinch performance of a plasma focus (PF) device is sensitive to the physical conditions of the breakdown phase. It is therefore essential to model and study the initial phase in order to optimize device performance. An external circuit is self consistently coupled to the electromagnetic particle in cell code to model the breakdown and initial lift phase of the United Nations University/International Centre for Theoretical Physics (UNU-ICTP) plasma focus device. Gas breakdown during the breakdown phase is simulated successfully, following a drop in the applied voltage across the device and a concurrent substantial rise in the circuit current. As a result, the plasma becomes magnetized, with the growing value of the magnetic field over time leading to the gradual lift off of the well formed current sheath into the axial acceleration phase. This lifting off, with simultaneous outward sheath motion along the anode and vertical cathode, and the strong magnetic fields in the current sheath region, was demonstrated in this work, and hence validates our method of coupling the external circuit to PF devices. Our method produces voltage waveforms that are qualitatively similar to the observed experimental voltage profiles of the UNU-ICTP device. Values of the mean electron energy before and after voltage breakdown turned out to be different, with the values after breakdown being much lower. In both cases, the electron energy density function turned out to be non-Maxwellian

  5. Effective lagrangian for strong interactions

    International Nuclear Information System (INIS)

    Jain, P.

    1988-01-01

    We attempt to construct a realistic phenomenological Lagrangian in order to describe strong interactions. This is in general a very complicated problem and we shall explore its various aspects. We first include the vector mesons by writing down the most general chiral invariant terms proportional to the Levi-Civita symbol ε μναβ . These terms involve three unknown coefficients, which are calculated by using the experimental results of strong interaction processes. We then calculate the static nucleon properties by finding the solitonic excitations of this model. The results turn out to be, as is also the case for most other vector-pseudoscalar Lagrangians, better than the Skyrme model but are still somewhat different from the experiments. Another aspect that we shall study is the incorporation of scale anomaly of QCD into the Skyrme model. We thus introduce a scalar glueball in our Lagrangian. Here we find an interesting result that the effective glue field dynamically forms a bag for the soliton. Depending on the values of the parameters, we get either a deep bag or a shallow bag. However by including the scalar meson, we find that to get realistic scalar sector we must have the shallow bag. Finally we show some intriguing connections between the chiral quark model, in which the nucleon is described as a solitonic excitation, and the ordinary potential binding quark model

  6. EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Ronning, Filip; Batista, Cristian

    2011-03-01

    Strongly correlated electrons is an exciting and diverse field in condensed matter physics. This special issue aims to capture some of that excitement and recent developments in the field. Given that this issue was inspired by the 2010 International Conference on Strongly Correlated Electron Systems (SCES 2010), we briefly give some history in order to place this issue in context. The 2010 International Conference on Strongly Correlated Electron Systems was held in Santa Fe, New Mexico, a reunion of sorts from the 1989 International Conference on the Physics of Highly Correlated Electron Systems that also convened in Santa Fe. SCES 2010—co-chaired by John Sarrao and Joe Thompson—followed the tradition of earlier conferences, in this century, hosted by Buzios (2008), Houston (2007), Vienna (2005), Karlsruhe (2004), Krakow (2002) and Ann Arbor (2001). Every three years since 1997, SCES has joined the International Conference on Magnetism (ICM), held in Recife (2000), Rome (2003), Kyoto (2006) and Karlsruhe (2009). Like its predecessors, SCES 2010 topics included strongly correlated f- and d-electron systems, heavy-fermion behaviors, quantum-phase transitions, non-Fermi liquid phenomena, unconventional superconductivity, and emergent states that arise from electronic correlations. Recent developments from studies of quantum magnetism and cold atoms complemented the traditional subjects and were included in SCES 2010. 2010 celebrated the 400th anniversary of Santa Fe as well as the birth of astronomy. So what's the connection to SCES? The Dutch invention of the first practical telescope and its use by Galileo in 1610 and subsequent years overturned dogma that the sun revolved about the earth. This revolutionary, and at the time heretical, conclusion required innovative combinations of new instrumentation, observation and mathematics. These same combinations are just as important 400 years later and are the foundation of scientific discoveries that were discussed

  7. Lessons learned from external hazards

    Energy Technology Data Exchange (ETDEWEB)

    Peinador, Miguel; Zerger, Benoit [European Commisison Joint Research Centre, Petten (Netherlands). Inst. for Energy and Transport; Ramos, Manuel Martin [European Commission Joint Research Centre, Brussels (Belgium). Nuclear Safety and Security Coordination; Wattrelos, Didier [Institut de Radioprotection et de Surete Nucleaire (IRSN), Fontenay-aux-Roses (France); Maqua, Michael [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Koeln (Germany)

    2014-01-15

    This paper presents a study performed by the European Clearinghouse of the Joint Research Centre on Operational Experience for nuclear power plants in cooperation with IRSN and GRS covering events reported by nuclear power plants in relation to external hazards. It summarizes the review of 235 event reports from 3 different databases. The events were grouped in 9 categories according to the nature of the external hazard involved, and the specific lessons learned and recommendations that can be derived from each of these categories are presented. Additional 'cross-cutting' recommendations covering several or all the external hazards considered are also discussed. These recommendations can be useful in preventing this type of events from happening again or in limiting their consequences. The study was launched in 2010 and therefore it does not cover the Fukushima event. This paper presents the main findings and recommendations raised by this study. (orig.)

  8. Strong Selective Adsorption of Polymers.

    Science.gov (United States)

    Ge, Ting; Rubinstein, Michael

    2015-06-09

    A scaling theory is developed for selective adsorption of polymers induced by the strong binding between specific monomers and complementary surface adsorption sites. By "selective" we mean specific attraction between a subset of all monomers, called "sticky", and a subset of surface sites, called "adsorption sites". We demonstrate that, in addition to the expected dependence on the polymer volume fraction ϕ bulk in the bulk solution, selective adsorption strongly depends on the ratio between two characteristic length scales, the root-mean-square distance l between neighboring sticky monomers along the polymer, and the average distance d between neighboring surface adsorption sites. The role of the ratio l / d arises from the fact that a polymer needs to deform to enable the spatial commensurability between its sticky monomers and the surface adsorption sites for selective adsorption. We study strong selective adsorption of both telechelic polymers with two end monomers being sticky and multisticker polymers with many sticky monomers between sticky ends. For telechelic polymers, we identify four adsorption regimes at l / d 1, we expect that the adsorption layer at exponentially low ϕ bulk consists of separated unstretched loops, while as ϕ bulk increases the layer crosses over to a brush of extended loops with a second layer of weakly overlapping tails. For multisticker chains, in the limit of exponentially low ϕ bulk , adsorbed polymers are well separated from each other. As l / d increases, the conformation of an individual polymer changes from a single-end-adsorbed "mushroom" to a random walk of loops. For high ϕ bulk , adsorbed polymers at small l / d are mushrooms that cover all the adsorption sites. At sufficiently large l / d , adsorbed multisticker polymers strongly overlap. We anticipate the formation of a self-similar carpet and with increasing l / d a two-layer structure with a brush of loops covered by a self-similar carpet. As l / d exceeds the

  9. IPEEE review of external events of the Asco I nuclear plant

    International Nuclear Information System (INIS)

    Aleman, A.; Canadell, F.; Beltran, F.; Pifarre, D.; Hernandez, H.; Gasca, C.

    2012-01-01

    During the risk analysis update of Asco NPP (2010), it has been carried out a review of the vulnerabilities against severe accidents caused by external events (individual Plant Examination of external Events, IPEEE). The assessment has includent analysis of accidents in industrial and military facilities nearby and transportation accidents (i.e., rail, road and aircraft impact) release of hazardous materials on site, external flooding, turbine missiles and strong winds. (Author)

  10. Infancy Parenting and Externalizing Psychopathology from Childhood through Adulthood: Developmental Trends

    OpenAIRE

    Lorber, Michael F.; Egeland, Byron

    2009-01-01

    Developmental models and previous findings suggest that early parenting is more strongly associated with externalizing problems in early childhood than in adolescence. In this brief report, we addressed the question of whether the association of poor quality infancy parenting and externalizing problems “rebounds” in adulthood. Poor quality infancy parenting was associated with externalizing problems at kindergarten and first grade (mother report), as well as at 23 and 26 years (self-report). ...

  11. Validity and Reliability in Social Science Research

    Science.gov (United States)

    Drost, Ellen A.

    2011-01-01

    In this paper, the author aims to provide novice researchers with an understanding of the general problem of validity in social science research and to acquaint them with approaches to developing strong support for the validity of their research. She provides insight into these two important concepts, namely (1) validity; and (2) reliability, and…

  12. External dosimetry sources and shielding

    International Nuclear Information System (INIS)

    Calisto, Washington

    1994-01-01

    A definition of external dosimetry r external sources dosimetry,physical and mathematical treatment of the interaction of gamma radiation with a minimal area in that direction. Concept of attenuation coefficient, cumulated effect by polyenergetic sources, exposition rate, units, cumulated dose,shielding, foton shielding, depth calculation, materials used for shielding.Beta shielding, consideration of range and maximum β energy , low stopping radiation by use of low Z shielding. Tables for β energy of β emitters, I (tau) factor, energy-range curves for β emitters in aqueous media, gamma attenuation factors for U, W and Pb. Y factor for bone tissue,muscle and air, build-up factors

  13. Strongly correlated quantum transport out-of-equilibrium

    Science.gov (United States)

    Dutt, Prasenjit

    The revolutionary advances in nanotechnology and nanofabrication have facilitated the precise control and manipulation of mesoscopic systems where quantum effects are pronounced. Quantum devices with tunable gates have made it possible to access regimes far beyond the purview of linear response theory. In particular, the influence of strong voltage and thermal biases has led to the observation of novel phenomena where the non-equilibrium characteristics of the system are of paramount importance. We study transport through quantum-impurity systems in the regime of strong correlations and determine the effects of large temperature and potential gradients on its many-body physics. In Part I of this thesis we focus on the steady-state dynamics of the system, a commonly encountered experimental scenario. For a system consisting of several leads composed of non-interacting electrons, each individually coupled to a quantum impurity with interactions and maintained at different chemical potentials, we reformulate the system in terms of an effective-equilibrium density matrix. This density matrix has a simple Boltzmann-like form in terms of the system's Lippmann-Schwinger (scattering) operators. We elaborate the conditions for this description to be valid based on the microscopic Hamiltonian of the system. We then prove the equivalence of physical observables computed using this formulation with corresponding expressions in the Schwinger-Keldysh approach and provide a dictionary between Green's functions in either scheme. An imaginary-time functional integral framework to compute finite temperature Green's functions is proposed and used to develop a novel perturbative expansion in the interaction strength which is exact in all other system parameters. We use these tools to study the fate of the Abrikosov-Suhl regime on the Kondo-correlated quantum dot due to the effects of bias and external magnetic fields. Next, we expand the domain of this formalism to additionally

  14. Strongly Deterministic Population Dynamics in Closed Microbial Communities

    Directory of Open Access Journals (Sweden)

    Zak Frentz

    2015-10-01

    Full Text Available Biological systems are influenced by random processes at all scales, including molecular, demographic, and behavioral fluctuations, as well as by their interactions with a fluctuating environment. We previously established microbial closed ecosystems (CES as model systems for studying the role of random events and the emergent statistical laws governing population dynamics. Here, we present long-term measurements of population dynamics using replicate digital holographic microscopes that maintain CES under precisely controlled external conditions while automatically measuring abundances of three microbial species via single-cell imaging. With this system, we measure spatiotemporal population dynamics in more than 60 replicate CES over periods of months. In contrast to previous studies, we observe strongly deterministic population dynamics in replicate systems. Furthermore, we show that previously discovered statistical structure in abundance fluctuations across replicate CES is driven by variation in external conditions, such as illumination. In particular, we confirm the existence of stable ecomodes governing the correlations in population abundances of three species. The observation of strongly deterministic dynamics, together with stable structure of correlations in response to external perturbations, points towards a possibility of simple macroscopic laws governing microbial systems despite numerous stochastic events present on microscopic levels.

  15. Infancy Parenting and Externalizing Psychopathology from Childhood through Adulthood: Developmental Trends

    Science.gov (United States)

    Lorber, Michael F.; Egeland, Byron

    2009-01-01

    Developmental models and previous findings suggest that early parenting is more strongly associated with externalizing problems in early childhood than it is in adolescence. In this article, the authors address whether the association of poor-quality infancy parenting and externalizing problems "rebounds" in adulthood. Poor-quality infancy…

  16. Strong growth for Queensland mining

    Energy Technology Data Exchange (ETDEWEB)

    1990-10-01

    The Queensland mining industry experienced strong growth during 1989-90 as shown in the latest statistics released by the Department of Resource Industries. The total value of Queensland mineral and energy production rose to a new record of $5.1 billion, an increase of 16.5% on 1988-89 production. A major contributing factor was a 20.9 percent increase in the value of coal production. While the quantity of coal produced rose only 1.1 percent, the substantial increase in the value of coal production is attributable to higher coal prices negotiated for export contracts. In Australian dollar terms coal, gold, lead, zinc and crude oil on average experienced higher international prices than in the previous year. Only copper and silver prices declined. 3 tabs.

  17. Strongly interacting W's and Z's

    International Nuclear Information System (INIS)

    Gaillard, M.K.

    1984-01-01

    The study focussed primarily on the dynamics of a strongly interacting W, Z(SIW) sector, with the aim of sharpening predictions for total W, Z yield and W, Z multiplicities expected from WW fusion for various scenarios. Specific issues raised in the context of the general problem of modeling SIW included the specificity of the technicolor (or, equivalently, QCD) model, whether or not a composite scalar model can be evaded, and whether the standard model necessarily implies an I = J = O state (≅ Higgs particle) that is relatively ''light'' (M ≤ hundreds of TeV). The consensus on the last issue was that existing arguments are inconclusive. While the author shall briefly address compositeness and alternatives to the technicolor model, quantitative estimates will be of necessity based on technicolor or an extrapolation of pion data

  18. Uniquely Strongly Clean Group Rings

    Institute of Scientific and Technical Information of China (English)

    WANG XIU-LAN

    2012-01-01

    A ring R is called clean if every element is the sum of an idempotent and a unit,and R is called uniquely strongly clean (USC for short) if every element is uniquely the sum of an idempotent and a unit that commute.In this article,some conditions on a ring R and a group G such that RG is clean are given.It is also shown that if G is a locally finite group,then the group ring RG is USC if and only if R is USC,and G is a 2-group.The left uniquely exchange group ring,as a middle ring of the uniquely clean ring and the USC ring,does not possess this property,and so does the uniquely exchange group ring.

  19. Economical evaluation of electricity generation considering externalities

    International Nuclear Information System (INIS)

    El-Kordy, M.N.; Badr, M.A.; Abed, K.A.; Ibrahim, Said M.A.

    2002-01-01

    The economics of renewable energy are the largest barrier to renewable penetration. Nevertheless, the strong desire to reduce environmental emissions is considered a great support for renewable energy sources. In this paper, a full analysis for the cost of the kWh of electricity generated from different systems actually used in Egypt is presented. Also renewable energy systems are proposed and their costs are analyzed. The analysis considers the external cost of emissions from different generating systems. A proposed large scale PV plant of 3.3 MW, and a wind farm 11.25 MW grid connected at different sites are investigated. A life cycle cost analysis for each system was performed using the present value criterion. The comparison results showed that wind energy generation has the lowest cost, followed by a combined cycle-natural gas fired system. A photovoltaic system still uses comparatively expensive technology for electricity generation; even when external costs are considered the capital cost of photovoltaic needs to be reduced by about 60% in order to be economically competitive. (Author)

  20. The impact of employee communication and perceived external prestige on organizational identification

    NARCIS (Netherlands)

    A. Smidts (Ale); C.B.M. van Riel (Cees); A.Th.H. Pruyn

    2000-01-01

    textabstractEmployees' Organizational Identification (OI) is measured in a customer service organization. Particularly the effects of employee communication and perceived external prestige (PEP) on OI were evaluated. Results show that employee communication affects OI more strongly than PEP. One

  1. Eating styles in the morbidly obese: restraint eating, but not emotional and external eating, predicts dietary behaviour.

    Science.gov (United States)

    Brogan, Amy; Hevey, David

    2013-01-01

    The research explored (1) the relationships between self-reported eating style (restraint, emotional and external eating) and dietary intake and (2) emotional eater status as a moderator of food intake when emotional, in a morbidly obese population. A sample of 57 obese participants (BMI: M = 51.84, SD = 8.66) completed a five-day food diary together with a reflective diary, which assessed eating style and positive and negative affect daily. A dietician-scored food pyramid analysis of intake. Restraint eating was the only predictor (negative) of overall food intake and the variable most strongly associated with the consumption of top-shelf foods. Emotional and external eating were unrelated to food intake. Emotional eater status did not moderate food intake in response to positive and negative mood states. The findings indicated largely analogous relationships between eating style and dietary intake in this obese sample compared with previous results from healthy populations. The lack of predictive validity for emotional eating scales (when emotional) raises questions over people's ability to adequately assess their eating style and consequently, the overall validity of emotional eater scales.

  2. Environmental externalities related to power production on biogas and natural gas based on the EU ExternE methodology

    DEFF Research Database (Denmark)

    Nielsen, Per Sieverts; Ibsen, Liselotte Schleisner

    1998-01-01

    This paper assesses the environmental impacts and external costs from selected electricity generation systems in Denmark. The assessment is carried out as part of the ExternE National Implementation, which is the second phase of the ExternE project and involves case studies from all Western...... European countries. The project use a “bottom-up” methodology to evaluate the external costs associated with a wide range of different fuel cycles. The project has identified priority impacts, where most are impacts from air emissions. Externalities due to atmospheric emissions are calculated through...

  3. Validation philosophy

    International Nuclear Information System (INIS)

    Vornehm, D.

    1994-01-01

    To determine when a set of calculations falls within an umbrella of an existing validation documentation, it is necessary to generate a quantitative definition of range of applicability (our definition is only qualitative) for two reasons: (1) the current trend in our regulatory environment will soon make it impossible to support the legitimacy of a validation without quantitative guidelines; and (2) in my opinion, the lack of support by DOE for further critical experiment work is directly tied to our inability to draw a quantitative open-quotes line-in-the-sandclose quotes beyond which we will not use computer-generated values

  4. Hydropower externalities: a meta analysis

    NARCIS (Netherlands)

    Mattmann, M.; Logar, I.; Brouwer, R.

    2016-01-01

    This paper presents a meta-analysis of existing research related to the economic valuation of the external effects of hydropower. A database consisting of 81 observations derived from 29 studies valuing the non-market impacts of hydropower electricity generation is constructed with the main aim to

  5. Matching Games with Additive Externalities

    DEFF Research Database (Denmark)

    Branzei, Simina; Michalak, Tomasz; Rahwan, Talal

    2012-01-01

    Two-sided matchings are an important theoretical tool used to model markets and social interactions. In many real life problems the utility of an agent is influenced not only by their own choices, but also by the choices that other agents make. Such an influence is called an externality. Whereas ...

  6. Organizing for External Knowledge Sourcing

    DEFF Research Database (Denmark)

    Rabbiosi, Larissa; Reichstein, Toke

    2011-01-01

    The aim of this article is to provide an introduction to the special issue. We briefly consider the external knowledge sourcing and organizing for innovation literatures, which offer a background for the special issue, and we highlight their mutual dialogue. We then illustrate the main findings o...

  7. Externally studentized normal midrange distribution

    Directory of Open Access Journals (Sweden)

    Ben Dêivide de Oliveira Batista

    Full Text Available ABSTRACT The distribution of externally studentized midrange was created based on the original studentization procedures of Student and was inspired in the distribution of the externally studentized range. The large use of the externally studentized range in multiple comparisons was also a motivation for developing this new distribution. This work aimed to derive analytic equations to distribution of the externally studentized midrange, obtaining the cumulative distribution, probability density and quantile functions and generating random values. This is a new distribution that the authors could not find any report in the literature. A second objective was to build an R package for obtaining numerically the probability density, cumulative distribution and quantile functions and make it available to the scientific community. The algorithms were proposed and implemented using Gauss-Legendre quadrature and the Newton-Raphson method in R software, resulting in the SMR package, available for download in the CRAN site. The implemented routines showed high accuracy proved by using Monte Carlo simulations and by comparing results with different number of quadrature points. Regarding to the precision to obtain the quantiles for cases where the degrees of freedom are close to 1 and the percentiles are close to 100%, it is recommended to use more than 64 quadrature points.

  8. Measuring Externalities in Program Evaluation

    NARCIS (Netherlands)

    Janssens, Wendy

    2005-01-01

    Impact evaluations of development programmes usually focus on a comparison of participants with a control group. However, if the programme generates externalities for non-participants such an approach will capture only part of the programme's impact. Based on a unique large-scale quantitative survey

  9. Quantum effects in strong fields

    International Nuclear Information System (INIS)

    Roessler, Lars

    2014-01-01

    This work is devoted to quantum effects for photons in spatially inhomogeneous fields. Since the purely analytical solution of the corresponding equations is an unsolved problem even today, a main aspect of this work is to use the worldline formalism for scalar QED to develop numerical algorithms for correlation functions beyond perturbative constructions. In a first step we take a look at the 2-Point photon correlation function, in order to understand effects like vacuum polarization or quantum reflection. For a benchmark test of the numerical algorithm we reproduce analytical results in a constant magnetic background. For inhomogeneous fields we calculate for the first time local refractive indices of the quantum vacuum. In this way we find a new de-focusing effect of inhomogeneous magnetic fields. Furthermore the numerical algorithm confirms analytical results for quantum reflection obtained within the local field approximation. In a second step we take a look at higher N-Point functions, with the help of our numerical algorithm. An interesting effect at the level of the 3-Point function is photon splitting. First investigations show that the Adler theorem remains also approximately valid for inhomogeneous fields.

  10. Alteration of the ground state by external magnetic fields. [External field, coupling constant ratio, static tree level approximation

    Energy Technology Data Exchange (ETDEWEB)

    Harrington, B J; Shepard, H K [New Hampshire Univ., Durham (USA). Dept. of Physics

    1976-03-22

    By fully exploiting the mathematical and physical analogy to the Ginzburg-Landau theory of superconductivity, a complete discussion of the ground state behavior of the four-dimensional Abelian Higgs model in the static tree level approximation is presented. It is shown that a sufficiently strong external magnetic field can alter the ground state of the theory by restoring a spontaneously broken symmetry, or by creating a qualitatively different 'vortex' state. The energetically favored ground state is explicitly determined as a function of the external field and the ratio between coupling constants of the theory.

  11. Self-injury and externalizing pathology: a systematic literature review.

    Science.gov (United States)

    Meszaros, Gergely; Horvath, Lili Olga; Balazs, Judit

    2017-05-03

    During the last decade there is a growing scientific interest in nonsuicidal self-injury (NSSI). The aim of the current paper was to review systematically the literature with a special focus on the associations between self-injurious behaviours and externalizing psychopathology. An additional aim was to review terminology and measurements of self-injurious behaviour and the connection between self-injurious behaviours and suicide in the included publications. A systematic literature search was conducted on 31st December 2016 in five databases (PubMed, OVID Medline, OVID PsycINFO, Scopus, Web of Science) with two categories of search terms (1. nonsuicidal self-injury, non-suicidal self-injury, NSSI, self-injurious behaviour, SIB, deliberate self-harm, DSH, self-injury; 2. externalizing disorder, attention deficit hyperactivity disorder, ADHD, conduct disorder, CD, oppositional defiant disorder, OD, ODD). Finally 35 papers were included. Eleven different terms were found for describing self-injurious behaviours and 20 methods for measuring it. NSSI has the clearest definition. All the examined externalizing psychopathologies had strong associations with self-injurious behaviours according to: higher prevalence rates in externalizing groups than in control groups, higher externalizing scores on the externalizing scales of questionnaires, higher symptom severity in self-injurious groups. Eight studies investigated the relationship between suicide and self-injurious behaviours and found high overlap between the two phenomena and similar risk factors. Based on the current findings the association between externalizing psychopathology and self-injurious behaviours has been proven by the scientific literature. Similarly to other reviews on self-injurious behaviours the confusion in terminology and methodology was noticed. NSSI is suggested for use as a distinct term. Further studies should investigate the role of comorbid conditions in NSSI, especially when internalizing

  12. External non-white noise and nonequilibrium phase transitions

    International Nuclear Information System (INIS)

    Sancho, J.M.; San Miguel, M.

    1980-01-01

    Langevin equations with external non-white noise are considered. A Fokker Planck equation valid in general in first order of the correlation time tau of the noise is derived. In some cases its validity can be extended to any value of tau. The effect of a finite tau in the nonequilibrium phase transitions induced by the noise is analyzed, by means of such Fokker Planck equation, in general, for the Verhulst equation under two different kind of fluctuations, and for a genetic model. It is shown that new transitions can appear and that the threshold value of the parameter can be changed. (orig.)

  13. Technical basis document for external events

    International Nuclear Information System (INIS)

    OBERG, B.D.

    2003-01-01

    This document supports the Tank Farms Documented Safety Analysis and presents the technical basis for the FR-equencies of externally initiated accidents. The consequences of externally initiated events are discussed in other documents that correspond to the accident that was caused by the external event. The external events include aircraft crash, vehicle accident, range fire, and rail accident

  14. Strong Ideal Convergence in Probabilistic Metric Spaces

    Indian Academy of Sciences (India)

    In the present paper we introduce the concepts of strongly ideal convergent sequence and strong ideal Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and establish some basic facts. Next, we define the strong ideal limit points and the strong ideal cluster points of a sequence in this ...

  15. Strong Statistical Convergence in Probabilistic Metric Spaces

    OpenAIRE

    Şençimen, Celaleddin; Pehlivan, Serpil

    2008-01-01

    In this article, we introduce the concepts of strongly statistically convergent sequence and strong statistically Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and establish some basic facts. Next, we define the strong statistical limit points and the strong statistical cluster points of a sequence in this space and investigate the relations between these concepts.

  16. Perturbative neutrino pair creation by an external source

    International Nuclear Information System (INIS)

    Koers, Hylke B.J.

    2005-01-01

    We consider the rate of fermion-antifermion pair creation by an external field. We derive a rate formula that is valid for a coupling with arbitrary vector and axial vector components to first order in perturbation theory. This is then applied to study the creation of neutrinos by nuclear matter, a problem with astrophysical relevance. We present an estimate for the creation rate per unit volume, compare this to previous results and comment on the role of the neutrino mass

  17. Impulsive Flocking of Dynamical Multiagent Systems with External Disturbances

    Directory of Open Access Journals (Sweden)

    Fujun Han

    2017-01-01

    Full Text Available Flocking motion of multiagent systems is influenced by various external disturbances in complex environment. By applying disturbance observer, flocking of multiagent systems with exogenous disturbances is studied. Based on the robust features of impulsive control, a distributed impulsive control protocol is presented with disturbance observer, and flocking motion of multiagent systems is analyzed. Moreover, a sufficient condition is obtained to ensure the flocking motion of multiagent systems following a leader. Finally, simulation results show the validity of the theoretical conclusion.

  18. Quantifying external focus of attention in sailing by means of action sport cameras

    NARCIS (Netherlands)

    Pluijms, Joost; Canal Bruland, R.; Hoozemans, M.J.M.; Beek, M.; Brocker, K.; Savelsbergh, G.J.P.

    2016-01-01

    The aim of the current study was twofold: (1) to validate the use of action sport cameras for quantifying focus of visual attention in sailing and (2) to apply this method to examine whether an external focus of attention is associated with better performance in upwind sailing. To test the validity

  19. John Strong - 1941-2006

    CERN Multimedia

    2006-01-01

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on 31 July, a few days before his 65th birthday. John started his career and obtained his PhD in a group from Westfield College, initially working on experiments at Rutherford Appleton Laboratory (RAL). From the early 1970s onwards, however, his research was focused on experiments in CERN, with several particularly notable contributions. The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras (a type of television camera) to record the sparks in the spark chambers. This highly automated system allowed Omega to be used in a similar way to bubble chambers. He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems. In these experiments the Westfield group joined forces with Italian colleagues to measure the form factors of the pion and the kaon, and the lifetime of some of the newly discovered charm particles. Such h...

  20. Remnants of strong tidal interactions

    International Nuclear Information System (INIS)

    Mcglynn, T.A.

    1990-01-01

    This paper examines the properties of stellar systems that have recently undergone a strong tidal shock, i.e., a shock which removes a significant fraction of the particles in the system, and where the shocked system has a much smaller mass than the producer of the tidal field. N-body calculations of King models shocked in a variety of ways are performed, and the consequences of the shocks are investigated. The results confirm the prediction of Jaffe for shocked systems. Several models are also run where the tidal forces on the system are constant, simulating a circular orbit around a primary, and the development of tidal radii under these static conditions appears to be a mild process which does not dramatically affect material that is not stripped. The tidal radii are about twice as large as classical formulas would predict. Remnant density profiles are compared with a sample of elliptical galaxies, and the implications of the results for the development of stellar populations and galaxies are considered. 38 refs

  1. Strongly correlated perovskite fuel cells

    Science.gov (United States)

    Zhou, You; Guan, Xiaofei; Zhou, Hua; Ramadoss, Koushik; Adam, Suhare; Liu, Huajun; Lee, Sungsik; Shi, Jian; Tsuchiya, Masaru; Fong, Dillon D.; Ramanathan, Shriram

    2016-06-01

    Fuel cells convert chemical energy directly into electrical energy with high efficiencies and environmental benefits, as compared with traditional heat engines. Yttria-stabilized zirconia is perhaps the material with the most potential as an electrolyte in solid oxide fuel cells (SOFCs), owing to its stability and near-unity ionic transference number. Although there exist materials with superior ionic conductivity, they are often limited by their ability to suppress electronic leakage when exposed to the reducing environment at the fuel interface. Such electronic leakage reduces fuel cell power output and the associated chemo-mechanical stresses can also lead to catastrophic fracture of electrolyte membranes. Here we depart from traditional electrolyte design that relies on cation substitution to sustain ionic conduction. Instead, we use a perovskite nickelate as an electrolyte with high initial ionic and electronic conductivity. Since many such oxides are also correlated electron systems, we can suppress the electronic conduction through a filling-controlled Mott transition induced by spontaneous hydrogen incorporation. Using such a nickelate as the electrolyte in free-standing membrane geometry, we demonstrate a low-temperature micro-fabricated SOFC with high performance. The ionic conductivity of the nickelate perovskite is comparable to the best-performing solid electrolytes in the same temperature range, with a very low activation energy. The results present a design strategy for high-performance materials exhibiting emergent properties arising from strong electron correlations.

  2. Strong seismic ground motion propagation

    International Nuclear Information System (INIS)

    Seale, S.; Archuleta, R.; Pecker, A.; Bouchon, M.; Mohammadioun, G.; Murphy, A.; Mohammadioun, B.

    1988-10-01

    At the McGee Creek, California, site, 3-component strong-motion accelerometers are located at depths of 166 m, 35 m and 0 m. The surface material is glacial moraine, to a depth of 30.5 m, overlying homfels. Accelerations were recorded from two California earthquakes: Round Valley, M L 5.8, November 23, 1984, 18:08 UTC and Chalfant Valley, M L 6.4, July 21, 1986, 14:42 UTC. By separating out the SH components of acceleration, we were able to determine the orientations of the downhole instruments. By separating out the SV component of acceleration, we were able to determine the approximate angle of incidence of the signal at 166 m. A constant phase velocity Haskell-Thomson model was applied to generate synthetic SH seismograms at the surface using the accelerations recorded at 166 m. In the frequency band 0.0 - 10.0 Hz, we compared the filtered synthetic records to the filtered surface data. The onset of the SH pulse is clearly seen, as are the reflections from the interface at 30.5 m. The synthetic record closely matches the data in amplitude and phase. The fit between the synthetic accelerogram and the data shows that the seismic amplification at the surface is a result of the contrast of the impedances (shear stiffnesses) of the near surface materials

  3. Effective Induction Heating around Strongly Magnetized Stars

    Science.gov (United States)

    Kislyakova, K. G.; Fossati, L.; Johnstone, C. P.; Noack, L.; Lüftinger, T.; Zaitsev, V. V.; Lammer, H.

    2018-05-01

    Planets that are embedded in the changing magnetic fields of their host stars can experience significant induction heating in their interiors caused by the planet’s orbital motion. For induction heating to be substantial, the planetary orbit has to be inclined with respect to the stellar rotation and dipole axes. Using WX UMa, for which the rotation and magnetic axes are aligned, as an example, we show that for close-in planets on inclined orbits, induction heating can be stronger than the tidal heating occurring inside Jupiter’s satellite Io; namely, it can generate a surface heat flux exceeding 2 W m‑2. An internal heating source of such magnitude can lead to extreme volcanic activity on the planet’s surface, possibly also to internal local magma oceans, and to the formation of a plasma torus around the star aligned with the planetary orbit. A strongly volcanically active planet would eject into space mostly SO2, which would then dissociate into oxygen and sulphur atoms. Young planets would also eject CO2. Oxygen would therefore be the major component of the torus. If the O I column density of the torus exceeds ≈1012 cm‑2, the torus could be revealed by detecting absorption signatures at the position of the strong far-ultraviolet O I triplet at about 1304 Å. We estimate that this condition is satisfied if the O I atoms in the torus escape the system at a velocity smaller than 1–10 km s‑1. These estimates are valid also for a tidally heated planet.

  4. EO Model for Tacit Knowledge Externalization in Socio-Technical Enterprises

    Directory of Open Access Journals (Sweden)

    Shreyas Suresh Rao

    2017-03-01

    Full Text Available Aim/Purpose: A vital business activity within socio-technical enterprises is tacit knowledge externalization, which elicits and explicates tacit knowledge of enterprise employees as external knowledge. The aim of this paper is to integrate diverse aspects of externalization through the Enterprise Ontology model. Background: Across two decades, researchers have explored various aspects of tacit knowledge externalization. However, from the existing works, it is revealed that there is no uniform representation of the externalization process, which has resulted in divergent and contradictory interpretations across the literature. Methodology\t: The Enterprise Ontology model is constructed step-wise through the conceptual and measurement views. While the conceptual view encompasses three patterns that model the externalization process, the measurement view employs certainty-factor model to empirically measure the outcome of the externalization process. Contribution: The paper contributes towards knowledge management literature in two ways. The first contribution is the Enterprise Ontology model that integrates diverse aspects of externalization. The second contribution is a Web application that validates the model through a case study in banking. Findings: The findings show that the Enterprise Ontology model and the patterns are pragmatic in externalizing the tacit knowledge of experts in a problem-solving scenario within a banking enterprise. Recommendations for Practitioners\t: Consider the diverse aspects (what, where, when, why, and how during the tacit knowledge externalization process. Future Research:\tTo extend the Enterprise Ontology model to include externalization from partially automated enterprise systems.

  5. Beta decay and other processes in strong electromagnetic fields

    International Nuclear Information System (INIS)

    Akhmedov, E. Kh.

    2011-01-01

    We consider effects of the fields of strong electromagnetic waves on various characteristics of quantum processes. After a qualitative discussion of the effects of external fields on the energy spectra and angular distributions of the final-state particles as well as on the total probabilities of the processes (such as decay rates and total cross sections), we present a simple method of calculating the total probabilities of processes with production of nonrelativistic charged particles. Using nuclear β decay as an example, we study the weak- and strong-field limits, as well as the field-induced β decay of nuclei stable in the absence of the external fields, both in the tunneling and multiphoton regimes. We also consider the possibility of accelerating forbidden nuclear β decays by lifting the forbiddeness due to the interaction of the parent or daughter nuclei with the field of a strong electromagnetic wave. It is shown that for currently attainable electromagnetic fields all effects on total β-decay rates are unobservably small.

  6. Strongly interacting photons and atoms

    International Nuclear Information System (INIS)

    Alge, W.

    1999-05-01

    This thesis contains the main results of the research topics I have pursued during the my PhD studies at the University of Innsbruck and partly in collaboration with the Institut d' Optique in Orsay, France. It is divided into three parts. The first and largest part discusses the possibility of using strong standing waves as a tool to cool and trap neutral atoms in optical cavities. This is very important in the field of nonlinear optics where several successful experiments with cold atoms in cavities have been performed recently. A discussion of the optical parametric oscillator in a regime where the nonlinearity dominates the evolution is the topic of the second part. We investigated mainly the statistical properties of the cavity output of the three interactive cavity modes. Very recently a system has been proposed which promises fantastic properties. It should exhibit a giant Kerr nonlinearity with negligible absorption thus leading to a photonic turnstile device based on cold atoms in cavity. We have shown that this model suffers from overly simplistic assumptions and developed several more comprehensive approaches to study the behavior of this system. Apart from the division into three parts of different contents the thesis is divided into publications, supplements and invisible stuff. The intention of the supplements is to reach researchers which work in related areas and provide them with more detailed information about the concepts and the numerical tools we used. It is written especially for diploma and PhD students to give them a chance to use the third part of our work which is actually the largest one. They consist of a large number of computer programs we wrote to investigate the behavior of the systems in parameter regions where no hope exists to solve the equations analytically. (author)

  7. Promoting Strong Written Communication Skills

    Science.gov (United States)

    Narayanan, M.

    2015-12-01

    The reason that an improvement in the quality of technical writing is still needed in the classroom is due to the fact that universities are facing challenging problems not only on the technological front but also on the socio-economic front. The universities are actively responding to the changes that are taking place in the global consumer marketplace. Obviously, there are numerous benefits of promoting strong written communication skills. They can be summarized into the following six categories. First, and perhaps the most important: The University achieves learner satisfaction. The learner has documented verbally, that the necessary knowledge has been successfully acquired. This results in learner loyalty that in turn will attract more qualified learners.Second, quality communication lowers the cost per pupil, consequently resulting in increased productivity backed by a stronger economic structure and forecast. Third, quality communications help to improve the cash flow and cash reserves of the university. Fourth, having high quality communication enables the university to justify the need for high costs of tuition and fees. Fifth, better quality in written communication skills result in attracting top-quality learners. This will lead to happier and satisfied learners, not to mention greater prosperity for the university as a whole. Sixth, quality written communication skills result in reduced complaints, thus meaning fewer hours spent on answering or correcting the situation. The University faculty and staff are thus able to devote more time on scholarly activities, meaningful research and productive community service. References Boyer, Ernest L. (1990). Scholarship reconsidered: Priorities of the Professorate.Princeton, NJ: Carnegie Foundation for the Advancement of Teaching. Hawkins, P., & Winter, J. (1997). Mastering change: Learning the lessons of the enterprise.London: Department for Education and Employment. Buzzel, Robert D., and Bradley T. Gale. (1987

  8. External costs of energy - do the answers match the questions? Looking back at 10 years of ExternE

    International Nuclear Information System (INIS)

    Krewitt, W.

    2002-01-01

    While the claim for 'getting prices right' is quite popular in conceptual policy papers, the implementation of appropriate internalisation strategies is still hampered by a lack of reliable external cost data. Great expectations were set into the ExternE project, a major research programme launched by the European Commission at the beginning of the 1990s to provide a scientific basis for the quantification of energy related externalities and to give guidance supporting the design of internalisation measures. After more than a decade of research, the ExternE label became a well recognised standard source for external cost data. Looking back into the ExternE history, the paper pursues how emerging new scientific insights and changing background assumptions affected external cost estimates and related recommendations to policy over time. Based on ExternE results, the usefulness and inherent limitations of external cost estimates for impact categories like climate change or nuclear waste disposal is discussed. The paper also gives examples on how external costs in spite of remaining uncertainties are successfully used to support environmental policy. (Author)

  9. Resolution-of-identity stochastic time-dependent configuration interaction for dissipative electron dynamics in strong fields.

    Science.gov (United States)

    Klinkusch, Stefan; Tremblay, Jean Christophe

    2016-05-14

    In this contribution, we introduce a method for simulating dissipative, ultrafast many-electron dynamics in intense laser fields. The method is based on the norm-conserving stochastic unraveling of the dissipative Liouville-von Neumann equation in its Lindblad form. The N-electron wave functions sampling the density matrix are represented in the basis of singly excited configuration state functions. The interaction with an external laser field is treated variationally and the response of the electronic density is included to all orders in this basis. The coupling to an external environment is included via relaxation operators inducing transition between the configuration state functions. Single electron ionization is represented by irreversible transition operators from the ionizing states to an auxiliary continuum state. The method finds its efficiency in the representation of the operators in the interaction picture, where the resolution-of-identity is used to reduce the size of the Hamiltonian eigenstate basis. The zeroth-order eigenstates can be obtained either at the configuration interaction singles level or from a time-dependent density functional theory reference calculation. The latter offers an alternative to explicitly time-dependent density functional theory which has the advantage of remaining strictly valid for strong field excitations while improving the description of the correlation as compared to configuration interaction singles. The method is tested on a well-characterized toy system, the excitation of the low-lying charge transfer state in LiCN.

  10. Resolution-of-identity stochastic time-dependent configuration interaction for dissipative electron dynamics in strong fields

    Energy Technology Data Exchange (ETDEWEB)

    Klinkusch, Stefan; Tremblay, Jean Christophe [Institute for Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 3, D-14195 Berlin (Germany)

    2016-05-14

    In this contribution, we introduce a method for simulating dissipative, ultrafast many-electron dynamics in intense laser fields. The method is based on the norm-conserving stochastic unraveling of the dissipative Liouville-von Neumann equation in its Lindblad form. The N-electron wave functions sampling the density matrix are represented in the basis of singly excited configuration state functions. The interaction with an external laser field is treated variationally and the response of the electronic density is included to all orders in this basis. The coupling to an external environment is included via relaxation operators inducing transition between the configuration state functions. Single electron ionization is represented by irreversible transition operators from the ionizing states to an auxiliary continuum state. The method finds its efficiency in the representation of the operators in the interaction picture, where the resolution-of-identity is used to reduce the size of the Hamiltonian eigenstate basis. The zeroth-order eigenstates can be obtained either at the configuration interaction singles level or from a time-dependent density functional theory reference calculation. The latter offers an alternative to explicitly time-dependent density functional theory which has the advantage of remaining strictly valid for strong field excitations while improving the description of the correlation as compared to configuration interaction singles. The method is tested on a well-characterized toy system, the excitation of the low-lying charge transfer state in LiCN.

  11. Firm Search for External Knowledge

    DEFF Research Database (Denmark)

    Sofka, Wolfgang; Grimpe, Christoph

    2012-01-01

    ignored the institutional context that provides or denies access to external knowledge at the country level. Combining institutional and knowledge search theory, we suggest that the market orientation of the institutional environment and the magnitude of institutional change influence when firms begin......The innovation performance of modern firms is increasingly determined by their ability to search and absorb external knowledge. However, after a certain threshold firms "oversearch" their environment and innovation performance declines. In this paper, we argue that prior literature has largely...... to experience the negative performance effects of oversearch. Based on a comprehensive sample of almost 8,000 firms from ten European countries, we find that institutions matter considerably for firms' search activity. Higher market orientation of institutions increases the effectiveness of firms' search...

  12. MGR External Events Hazards Analysis

    International Nuclear Information System (INIS)

    Booth, L.

    1999-01-01

    The purpose and objective of this analysis is to apply an external events Hazards Analysis (HA) to the License Application Design Selection Enhanced Design Alternative 11 [(LADS EDA II design (Reference 8.32))]. The output of the HA is called a Hazards List (HL). This analysis supersedes the external hazards portion of Rev. 00 of the PHA (Reference 8.1). The PHA for internal events will also be updated to the LADS EDA II design but under a separate analysis. Like the PHA methodology, the HA methodology provides a systematic method to identify potential hazards during the 100-year Monitored Geologic Repository (MGR) operating period updated to reflect the EDA II design. The resulting events on the HL are candidates that may have potential radiological consequences as determined during Design Basis Events (DBEs) analyses. Therefore, the HL that results from this analysis will undergo further screening and analysis based on the criteria that apply during the performance of DBE analyses

  13. Leveraging External Sources of Innovation

    DEFF Research Database (Denmark)

    West, Joel; Bogers, Marcel

    2014-01-01

    , it suggests a four-phase model in which a linear process—(1) obtaining, (2) integrating, and (3) commercializing external innovations—is combined with (4) interaction between the firm and its collaborators. This model is used to classify papers taken from the top 25 innovation journals, complemented by highly...... cited work beyond those journals. A review of 291 open innovation-related publications from these sources shows that the majority of these articles indeed address elements of this inbound open innovation process model. Specifically, it finds that researchers have front-loaded their examination...... external innovations create value rather than how firms capture value from those innovations. Finally, the interaction phase considers both feedback for the linear process and reciprocal innovation processes such as cocreation, network collaboration, and community innovation. This review and synthesis...

  14. Quasinormal Modes and Strong Cosmic Censorship

    Science.gov (United States)

    Cardoso, Vitor; Costa, João L.; Destounis, Kyriakos; Hintz, Peter; Jansen, Aron

    2018-01-01

    The fate of Cauchy horizons, such as those found inside charged black holes, is intrinsically connected to the decay of small perturbations exterior to the event horizon. As such, the validity of the strong cosmic censorship (SCC) conjecture is tied to how effectively the exterior damps fluctuations. Here, we study massless scalar fields in the exterior of Reissner-Nordström-de Sitter black holes. Their decay rates are governed by quasinormal modes of the black hole. We identify three families of modes in these spacetimes: one directly linked to the photon sphere, well described by standard WKB-type tools; another family whose existence and time scale is closely related to the de Sitter horizon; finally, a third family which dominates for near-extremally charged black holes and which is also present in asymptotically flat spacetimes. The last two families of modes seem to have gone unnoticed in the literature. We give a detailed description of linear scalar perturbations of such black holes, and conjecture that SCC is violated in the near extremal regime.

  15. Personnel external dose monitoring system

    International Nuclear Information System (INIS)

    Zhao Hengyuan

    1989-01-01

    The status and trend of personnel external dose monitoring system are introduced briefly. Their characteristics, functions and TLD bedges of some commercially available automatic TLD system, including UD-710A (Matsushita, Japan), Harshaw-2271, 2276 (Harshaw, USA), Harshaw-8000 (Harshaw/Filtrol), Studsvik-1313 (Sweden) and Pitman-800 (UK) were depicted in detail. Finally, personnel dose management and record keeping system were presented and two examples were given

  16. Russia needs a strong counterpart

    International Nuclear Information System (INIS)

    Slovak, K.; Marcan, P.

    2008-01-01

    In this paper an interview with the head of OMV, Wolfgang Ruttenstorfer is published. There is extract from this interview: Q: There have been attempts to take over MOL for a quite long time. Do you think you can still succeed? Since the beginning we kept saying that this would not happen from one day to another. But it may take two to three years. But we are positive that it is justified. Q: Resistance from MOL and the Hungarian government is strong. We have tried to persuade the Hungarian government. We offered them a split company management. A part of the management would be in Budapest. We would locate the management of the largest division - the refinery, there. And of course only the best could be part of the management. We would not nominate people according to their nationality, it would not matter whether the person was Austrian, Hungarian or Slovak. We want a Central European company, not Hungarian, Romanian or Slovak company. Q: Would the transaction still be attractive if, because of pressure exercised by Brussels, you had to sell Slovnaft or your refinery in Szazhalobatta? We do not intend to sell any refineries. Q: Rumours are spreading that the Commission may ask you to sell a refinery? We do not want to speculate. Let us wait and see what happens. We do not want to sell refineries. Q: It is said that OMV is coordinating or at least consulting its attempts to acquire MOL with Gazprom. There are many rumours in Central Europe. But I can tell you this is not true. We are interested in this merger because we feel the increasing pressure exercised by Kazakhstan and Russia. We, of course, have a good relationship with Gazprom which we have had enjoyed for over forty years. As indeed Slovakia has. Q: A few weeks ago Austrian daily Wirtschaftsblatt published an article about Gazprom's interest in OMV shares. That is gossip that is more than ten years' old. Similarly to the rumours that Gazprom is a shareholder of MOL. There are no negotiations with Gazprom

  17. External fixation of "intertrochanteric" fractures.

    Science.gov (United States)

    Gani, Naseem Ul; Kangoo, Khursheed Ahmed; Bashir, Arshad; Muzaffer, Rahil; Bhat, Mohammad Farooq; Farooq, Munir; Badoo, Abdul Rashid; Dar, Imtiyaz Hussian; Wani, Mudassir Maqbool

    2009-10-10

    In developing countries, due to limited availability of modern anesthesia and overcrowding of the hospitals with patients who need surgery, high-risk patients with "intertrochanteric" fractures remain unsuita ble for open reduction and internal fixation.The aim of this study was to analyze the results of external fixation of "intertrochanteric" fractures in high-risk geriatric patients in a developing country.The results of 62 ambulatory high-risk geriatric patients with a mean age of 70 years (range 58-90 years) with "intertrochanteric" fractures, in whom external fixation was performed, are reported.Eight patients died during follow-up due to medical causes unrelated to the surgical procedure. So only 54 patients were available for final assessment. Procedure is simple, performed under local anesthesia, requires less time for surgery and is associated with less blood loss. Good fixation and early ambulation was achieved in most of the patients. Average time to union was 14 weeks. Thirty-one patients developed superficial pin tract infection and 28 patients had average shortening of 15 mm due to impaction and varus angulation. Functional outcome was assessed using Judet's point system. Good to excellent results were achieved in 44 patients.This study demonstrated that external fixation of "intertrochantric" fractures performed under local anesthesia offers significant advantage in ambulatory high-risk geriatric patients especially in a developing country.

  18. ExternE: Externalities of energy Vol. 4. Oil and gas

    International Nuclear Information System (INIS)

    Friedrich, R.; Krewitt, W.; Mayerhofer, P.

    1995-01-01

    Awareness of the environmental damage resulting from human activity, particularly commencing energy use, has grown greatly in recent years. Effects such as global warming, ozone depletion and acid rain are now the subjects of much research and public debate. It is now known that these and other effects damage a wide range of receptors, including human health, forests, crops, freshwater ecosystems and buildings. Such damages are typically not accounted for by the producers and consumers of the good in question (in this case energy). They are thus referred to as 'external costs' or 'externalities', to distinguish them from the private costs which account for the construction of plant, cost of fuel, wages, etc. In recent years there has been a growing interest in the assessment of the environmental and health impacts of energy, and the related external costs. This concern is driven by a number of different factors: the need to integrate environmental concerns in decision making over the choice between different fuels and energy technologies; the need to evaluate the costs and benefits of stricter environmental standards; increased attention to the use of economic instruments for environmental policy, the need to develop overall indicators of environmental performance of different technologies; major changes in the energy sector, including privatisation, liberalisation of markets, reduction of subsidies, etc. An agreed methodology for calculation and integration of external costs has not been established. Earlier work is typically of a preliminary nature and tends to be deficient with respect to both the methods employed and the quality of models and data used. In consequence of this a collaborative project, the EC/US Fuel Cycles Study, was established between Directorate General XLI (Science, Research and Technology) of the European Commission and the United States Department of Energy. This ran for the period 1991 to 1993, and good agreement on a variety of

  19. Canonical Transform Method for Treating Strongly Anisotropy Magnets

    DEFF Research Database (Denmark)

    Cooke, J. F.; Lindgård, Per-Anker

    1977-01-01

    An infinite-order perturbation approach to the theory of magnetism in magnets with strong single-ion anisotropy is given. This approach is based on a canonical transformation of the system into one with a diagonal crystal field, an effective two-ion anisotropy, and reduced ground-state corrections....... A matrix-element matching procedure is used to obtain an explicit expression for the spin-wave energy to second order. The consequences of this theory are illustrated by an application to a simple example with planar anisotropy and an external magnetic field. A detailed comparison between the results...

  20. NATO Advanced Study Institute on Atoms in Strong Fields

    CERN Document Server

    Clark, Charles; Nayfeh, Munir

    1990-01-01

    This book collects the lectures given at the NATO Advanced Study Institute on "Atoms in Strong Fields", which took place on the island of Kos, Greece, during the two weeks of October 9-21,1988. The designation "strong field" applies here to an external electromagnetic field that is sufficiently strong to cause highly nonlinear alterations in atomic or molecular struc­ ture and dynamics. The specific topics treated in this volume fall into two general cater­ gories, which are those for which strong field effects can be studied in detail in terrestrial laboratories: the dynamics of excited states in static or quasi-static electric and magnetic fields; and the interaction of atoms and molecules with intense laser radiation. In both areas there exist promising opportunities for research of a fundamental nature. An electric field of even a few volts per centimeter can be very strong on the atom­ ic scale, if it acts upon a weakly bound state. The study of Rydberg states with high reso­ lution laser spectroscop...

  1. Strong Motion Seismograph Based On MEMS Accelerometer

    Science.gov (United States)

    Teng, Y.; Hu, X.

    2013-12-01

    The MEMS strong motion seismograph we developed used the modularization method to design its software and hardware.It can fit various needs in different application situation.The hardware of the instrument is composed of a MEMS accelerometer,a control processor system,a data-storage system,a wired real-time data transmission system by IP network,a wireless data transmission module by 3G broadband,a GPS calibration module and power supply system with a large-volumn lithium battery in it. Among it,the seismograph's sensor adopted a three-axis with 14-bit high resolution and digital output MEMS accelerometer.Its noise level just reach about 99μg/√Hz and ×2g to ×8g dynamically selectable full-scale.Its output data rates from 1.56Hz to 800Hz. Its maximum current consumption is merely 165μA,and the device is so small that it is available in a 3mm×3mm×1mm QFN package. Furthermore,there is access to both low pass filtered data as well as high pass filtered data,which minimizes the data analysis required for earthquake signal detection. So,the data post-processing can be simplified. Controlling process system adopts a 32-bit low power consumption embedded ARM9 processor-S3C2440 and is based on the Linux operation system.The processor's operating clock at 400MHz.The controlling system's main memory is a 64MB SDRAM with a 256MB flash-memory.Besides,an external high-capacity SD card data memory can be easily added.So the system can meet the requirements for data acquisition,data processing,data transmission,data storage,and so on. Both wired and wireless network can satisfy remote real-time monitoring, data transmission,system maintenance,status monitoring or updating software.Linux was embedded and multi-layer designed conception was used.The code, including sensor hardware driver,the data acquisition,earthquake setting out and so on,was written on medium layer.The hardware driver consist of IIC-Bus interface driver, IO driver and asynchronous notification driver. The

  2. Adaptation and Validation of the Brief Sexual Opinion Survey (SOS) in a Colombian Sample and Factorial Equivalence with the Spanish Version

    Science.gov (United States)

    Sierra, Juan Carlos; Soler, Franklin

    2016-01-01

    Attitudes toward sexuality are a key variable for sexual health. It is really important for psychology and education to have adapted and validated questionnaires to evaluate these attitudes. Therefore, the objective of this research was to adapt, validate and calculate the equivalence of the Colombia Sexual Opinion Survey as compared to the same survey from Spain. To this end, a total of eight experts were consulted and 1,167 subjects from Colombia and Spain answered the Sexual Opinion Survey, the Sexual Assertiveness Scale, the Massachusetts General Hospital-Sexual Functioning Questionnaire, and the Sexuality Scale. The evaluation was conducted by online and the results show adequate qualitative and quantitative properties of the items, with adequate reliability and external validity and compliance with the strong invariance between the two countries. Consequently, the Colombia Sexual Opinion Survey is a valid and reliable scale and its scores can be compared with the ones from the Spain survey, with minimum bias. PMID:27627114

  3. All Validity Is Construct Validity. Or Is It?

    Science.gov (United States)

    Kane, Michael

    2012-01-01

    Paul E. Newton's article on the consensus definition of validity tackles a number of big issues and makes a number of strong claims. I agreed with much of what he said, and I disagreed with a number of his claims, but I found his article to be consistently interesting and thought provoking (whether I agreed or not). I will focus on three general…

  4. Validation of psychoanalytic theories: towards a conceptualization of references.

    Science.gov (United States)

    Zachrisson, Anders; Zachrisson, Henrik Daae

    2005-10-01

    The authors discuss criteria for the validation of psychoanalytic theories and develop a heuristic and normative model of the references needed for this. Their core question in this paper is: can psychoanalytic theories be validated exclusively from within psychoanalytic theory (internal validation), or are references to sources of knowledge other than psychoanalysis also necessary (external validation)? They discuss aspects of the classic truth criteria correspondence and coherence, both from the point of view of contemporary psychoanalysis and of contemporary philosophy of science. The authors present arguments for both external and internal validation. Internal validation has to deal with the problems of subjectivity of observations and circularity of reasoning, external validation with the problem of relevance. They recommend a critical attitude towards psychoanalytic theories, which, by carefully scrutinizing weak points and invalidating observations in the theories, reduces the risk of wishful thinking. The authors conclude by sketching a heuristic model of validation. This model combines correspondence and coherence with internal and external validation into a four-leaf model for references for the process of validating psychoanalytic theories.

  5. Strongly trapped points and the cosmic censorship hypothesis

    International Nuclear Information System (INIS)

    Krolak, A.

    1987-01-01

    It is shown that singularities predicted by one of the theorems of Hawking cannot be naked. This result supports the validity of the cosmic censorship hypothesis put forward by Penrose. The condition that only singularities predicted by Hawking's singularity theorem occur in space-time is shown to be related to the condition that all singularities in space-time should be of Tipler's strong-curvature type

  6. The state of external equilibrium in Croatia and its long term stability

    Directory of Open Access Journals (Sweden)

    Dražen Derado

    2002-01-01

    Full Text Available From the outset of transition Croatia faces a serious problem of external imbalance as a consequence of unfinished structural and institutional reforms. The external balance crisis can be seen through raising international trade deficit and structural characteristics of trade flows. To these unfavorable characteristics belong export reorientation from developed to less developed countries, increasing number of industries in which Croatia has position of net-importer and export structure in which dominate low-value-added products. Increasing trade deficit in 2001 and 2002 followed by further growth in external indebtedness cause increasing burden of debt service and limit the possibilities for economic growth. Taking all this as well as real limits in further external imbalance growth into consideration it can be said that Croatia realizes high level of external disequilibrium. In contrast, advanced transition countries achieve fairly good and stabile external positions thanks to successful economic restructuring and strong export growth.

  7. Rrsm: The European Rapid Raw Strong-Motion Database

    Science.gov (United States)

    Cauzzi, C.; Clinton, J. F.; Sleeman, R.; Domingo Ballesta, J.; Kaestli, P.; Galanis, O.

    2014-12-01

    We introduce the European Rapid Raw Strong-Motion database (RRSM), a Europe-wide system that provides parameterised strong motion information, as well as access to waveform data, within minutes of the occurrence of strong earthquakes. The RRSM significantly differs from traditional earthquake strong motion dissemination in Europe, which has focused on providing reviewed, processed strong motion parameters, typically with significant delays. As the RRSM provides rapid open access to raw waveform data and metadata and does not rely on external manual waveform processing, RRSM information is tailored to seismologists and strong-motion data analysts, earthquake and geotechnical engineers, international earthquake response agencies and the educated general public. Access to the RRSM database is via a portal at http://www.orfeus-eu.org/rrsm/ that allows users to query earthquake information, peak ground motion parameters and amplitudes of spectral response; and to select and download earthquake waveforms. All information is available within minutes of any earthquake with magnitude ≥ 3.5 occurring in the Euro-Mediterranean region. Waveform processing and database population are performed using the waveform processing module scwfparam, which is integrated in SeisComP3 (SC3; http://www.seiscomp3.org/). Earthquake information is provided by the EMSC (http://www.emsc-csem.org/) and all the seismic waveform data is accessed at the European Integrated waveform Data Archive (EIDA) at ORFEUS (http://www.orfeus-eu.org/index.html), where all on-scale data is used in the fully automated processing. As the EIDA community is continually growing, the already significant number of strong motion stations is also increasing and the importance of this product is expected to also increase. Real-time RRSM processing started in June 2014, while past events have been processed in order to provide a complete database back to 2005.

  8. Estimating location without external cues.

    Directory of Open Access Journals (Sweden)

    Allen Cheung

    2014-10-01

    Full Text Available The ability to determine one's location is fundamental to spatial navigation. Here, it is shown that localization is theoretically possible without the use of external cues, and without knowledge of initial position or orientation. With only error-prone self-motion estimates as input, a fully disoriented agent can, in principle, determine its location in familiar spaces with 1-fold rotational symmetry. Surprisingly, localization does not require the sensing of any external cue, including the boundary. The combination of self-motion estimates and an internal map of the arena provide enough information for localization. This stands in conflict with the supposition that 2D arenas are analogous to open fields. Using a rodent error model, it is shown that the localization performance which can be achieved is enough to initiate and maintain stable firing patterns like those of grid cells, starting from full disorientation. Successful localization was achieved when the rotational asymmetry was due to the external boundary, an interior barrier or a void space within an arena. Optimal localization performance was found to depend on arena shape, arena size, local and global rotational asymmetry, and the structure of the path taken during localization. Since allothetic cues including visual and boundary contact cues were not present, localization necessarily relied on the fusion of idiothetic self-motion cues and memory of the boundary. Implications for spatial navigation mechanisms are discussed, including possible relationships with place field overdispersion and hippocampal reverse replay. Based on these results, experiments are suggested to identify if and where information fusion occurs in the mammalian spatial memory system.

  9. Matchings with Externalities and Attitudes

    DEFF Research Database (Denmark)

    Branzei, Simina; Michalak, Tomasz; Rahwan, Talal

    2013-01-01

    Two-sided matchings are an important theoretical tool used to model markets and social interactions. In many real-life problems the utility of an agent is influenced not only by their own choices, but also by the choices that other agents make. Such an influence is called an externality. Whereas ...... where agents take different attitudes when reasoning about the actions of others. In particular, we study optimistic, neutral and pessimistic attitudes and provide both computational hardness results and polynomial-time algorithms for computing stable outcomes....

  10. Nuclear energy and external constraints

    International Nuclear Information System (INIS)

    Lattes, R.; Thiriet, L.

    1983-01-01

    The structural factors of this crisis probably predominate over factors arising out the economic situation, even if explanations vary in this respect. In this article devoted to nuclear energy, a possible means of Loosering external constraints the current international economic environment is firstly outlined; the context in which the policies of industrialized countries, and therefore that of France, must be developed. An examination of the possible role of energy policies in general and nuclear policies in particular as an instrument of economic policy in providing a partial solution to this crisis, will then enable to quantitatively evaluate the effects of such policies at a national level [fr

  11. [A Validation Study of the Modified Korean Version of Ethical Leadership at Work Questionnaire (K-ELW)].

    Science.gov (United States)

    Kim, Jeong-Eon; Park, Eun-Jun

    2015-04-01

    The purpose of this study was to validate the Korean version of the Ethical Leadership at Work questionnaire (K-ELW) that measures RNs' perceived ethical leadership of their nurse managers. The strong validation process suggested by Benson (1998), including translation and cultural adaptation stage, structural stage, and external stage, was used. Participants were 241 RNs who reported their perceived ethical leadership using both the pre-version of K-ELW and a previously known Ethical Leadership Scale, and interactional justice of their managers, as well as their own demographics, organizational commitment and organizational citizenship behavior. Data analyses included descriptive statistics, Pearson correlation coefficients, reliability coefficients, exploratory factor analysis, and confirmatory factor analysis. SPSS 19.0 and Amos 18.0 versions were used. A modified K-ELW was developed from construct validity evidence and included 31 items in 7 domains: People orientation, task responsibility fairness, relationship fairness, power sharing, concern for sustainability, ethical guidance, and integrity. Convergent validity, discriminant validity, and concurrent validity were supported according to the correlation coefficients of the 7 domains with other measures. The results of this study provide preliminary evidence that the modified K-ELW can be adopted in Korean nursing organizations, and reliable and valid ethical leadership scores can be expected.

  12. Waveguide based external cavity semiconductor lasers

    NARCIS (Netherlands)

    Oldenbeuving, Ruud; Klein, E.J.; Offerhaus, Herman L.; Lee, Christopher James; Verhaegen, M.; Boller, Klaus J.

    2012-01-01

    We report on progress of the project waveguide based external cavity semiconductor laser (WECSL) arrays. Here we present the latest results on our efforts to mode lock an array of tunable, external cavity semiconductor lasers.

  13. Internalising external costs of electricity and heat production in a municipal energy system

    International Nuclear Information System (INIS)

    Holmgren, Kristina; Amiri, Shahnaz

    2007-01-01

    Both energy supply and waste treatment give rise to negative effects on the environment, so-called external effects. In this study, monetary values on external costs collected from the EU's ExternE project are used to evaluate inclusion of these costs in comparison with an energy utility perspective including present policy instruments. The studied object is a municipal district heating system with a waste incineration plant as the base supplier of heat. The evaluation concerns fuels used for heat production and total electricity production, for scenarios with external costs included and for a scenario using the present policy instrument. Impacts of assumptions on marginal power producers (coal or natural gas power plants) are investigated, since locally produced electricity is assumed to replace marginal power and thus is credited for the avoided burden. Varying levels of external costs for carbon dioxide emissions are analysed. The method used is an economic optimisation model, MODEST. The conclusion is that present policy instruments are strong incentives for cogeneration, even when external costs are included. Waste is fully utilised in all scenarios. In cases where coal is the marginal power producer, more electricity is produced; when natural gas is the marginal power producer, less is produced. There are several uncertainties in the data for external costs, both methodological and ethical. In the ExternE data, not all environmental impacts are included. For waste incineration, ashes are not included, and another difficulty is how to treat the avoided burden of other waste treatment methods

  14. Externalized ileocolic anastomosis: case report.

    Science.gov (United States)

    Simcock, James; Kuntz, Charles A; Newman, Raquel

    2010-01-01

    A 6-year-old, spayed female Labrador retriever was presented 48 hours after an intestinal resection and anastomosis for management of a small intestinal foreign body. Abdominal ultrasound confirmed the presence of peritoneal effusion. Cytology of fluid collected by abdominocentesis revealed a large number of degenerate neutrophils with intracellular cocci. A diagnosis of septic peritonitis was made, presumably because of dehiscence of the anastomosis. Upon repeat exploratory celiotomy, the intestinal anastomosis (located 4 cm orad to the cecum) was found to be leaking intestinal contents into the abdomen. The distal ileum, cecum, and proximal colon were resected. An end-to-end, ileocolic anastomosis was performed and subsequently exteriorized into the subcutaneous space via a paramedian incision through the abdominal wall. The anastomosis was inspected daily for 4 days before it was returned to the abdomen and the subcutaneous defect was closed. Serial cytology of the peritoneal fluid, which was performed during this 4-day postoperative period, confirmed progressive resolution of peritonitis. The dog was discharged from the hospital 2 days following return of the anastomosis into the abdomen. Externalized intestinal anastomosis is used with good success in human medicine for repair of colonic injuries. In this case, externalization of the anastomosis permitted healing of the intestinal anastomosis in an environment isolated from the detrimental effects created by septic peritonitis. In addition, direct visualization of the anastomosis allowed assessment of healing. To our knowledge, this procedure has not been previously reported in companion animals.

  15. Effects of Externalities on Patterns of Exchange

    NARCIS (Netherlands)

    Dijkstra, J.; van Assen, M.A.L.M.

    Many real−life examples of exchanges with externalities exist. Externalities of exchange are defined as direct consequences of exchanges for the payoff of actors who are not involved in the exchange. This paper focuses on how externalities influence the partner choice in exchange networks. In an

  16. The external cruising costs of parking

    NARCIS (Netherlands)

    Inci, E.; van Ommeren, J.N.; Kobus, Martijn

    2017-01-01

    Existing work emphasizes the importance of traffic congestion externalities, but typically ignores cruising-for-parking externalities. We estimate the marginal external cruising costs of parking—that is, the time costs that an additional parked car imposes on drivers by inducing them to cruise for

  17. ExternE: Externalities of energy Vol. 3. Coal and lignite

    International Nuclear Information System (INIS)

    Berry, J.; Holland, M.; Lee, D.

    1995-01-01

    Awareness of the environmental damage resulting from human activity, particularly concerning energy use, has grown greatly in recent years. Effects such as global warming, ozone depletion and acid rain are now the subjects of much research and public debate. It is now known that these and other effects damage a wide range of receptors, including human health, forests, crops, freshwater ecosystems and buildings. Such damages are typically not accounted for by the producers and consumers of the good in question (in this case energy). They are thus referred to as 'external costs' or 'externalities', to distinguish them from the private costs which account for the construction of plant, cost of fuel, wages, etc. In recent years there has been a growing interest in the assessment of the environmental and health impacts of energy, and the related external costs. This concern is driven by a number of different factors: the need to integrate environmental concerns in decision making over the choice between different fuels and energy technologies; the need to evaluate the costs and benefits of stricter environmental standards; increased attention to the use of economic instruments for environmental policy; the need to develop overall indicators of environmental performance of different technologies; major changes in the energy sector, including privatisation, liberalisation of markets, reduction of subsidies, etc. An agreed methodology for calculation and integration of external costs has not been established. Earlier work is typically of a preliminary nature and tends to be deficient with respect to both the methods employed and the quality of models and data used. In consequence of this a collaborative project, the EC/US Fuel Cycles Study, was established between Directorate General XII (Science, Research and Technology) of the European Commission and the United States Department of Energy. This ran for the period 1991 to 1993, and good agreement on a variety of

  18. Pure global externalities. International efficiency and equity

    International Nuclear Information System (INIS)

    Musgrave, P.B.

    1995-01-01

    The argument for a carbon tax to reduce CO 2 emissions to the global arena is extended and the distribution as well as efficiency issues posed by a global agreement on carbon taxation are examined. The author distinguishes four alternative international arrangements in addition to the 'no cooperation' case. The arrangements allow for various equity rules to reflect what are considered to be equitable changes from the baseline position. Although the results of Musgrave's exercise lay no strong claims to validity as empirical findings, the relative patterns that emerge, nonetheless, contribute to an understanding of the issues that must be faced in arriving at acceptable international forms of cooperation. 1 fig., 6 tabs., 10 refs

  19. Interaction of neutral particles with strong laser fields

    Energy Technology Data Exchange (ETDEWEB)

    Meuren, Sebastian; Keitel, Christoph H.; Di Piazza, Antonino [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)

    2013-07-01

    Since the invention of the laser in the 1960s the experimentally available field strengths have continuously increased. The current peak intensity record is 2 x 10{sup 22} W/cm{sup 2} and next generation facilities such as ELI, HiPER and XCELS plan to reach even intensities of the order of 10{sup 24} W/cm{sup 2}. Thus, modern laser facilities are a clean source for very strong external electromagnetic fields and promise new and interesting high-energy physics experiments. In particular, strong laser fields could be used to test non-linear effects in quantum field theory. Earlier we have investigated how radiative corrections modify the coupling of a charged particle inside a strong plane-wave electromagnetic background field. However, a charged particle couples already at tree level to electromagnetic radiation. Therefore, we have now analyzed how the coupling between neutral particles and radiation is affected by a very strong plane-wave electromagnetic background field, when loop corrections are taken into account. In particular, the case of neutrinos is discussed.

  20. An experimental study of the effect of external thermocouples on rewetting during reflood

    International Nuclear Information System (INIS)

    Shires, G.L.; Butcher, A.A.; Carpenter, B.G.; McCune, D.S.; Pearson, K.G.

    1980-04-01

    The validation of computer codes used for PWR safety assessment often depends upon experiments carried out with either real fuel pins or electrically heated fuel pin simulators. In some cases, and this applies particularly to in-pile tests, temperatures are measured by means of sheathed thermocouples attached externally to the pins and this raises the question of the possible effect of such thermocouples on the two phase hydraulics and heat transfer which are being studied. This paper describes the experiments which subjected two realistic fuel pin simulators, one with and one without external thermocouples, to identical bottom flooding conditions. They demonstrate very clearly that external thermocouples act as preferential rewetting sites and thereby increase the rate of propagation of the quench front. In the view of the authors of this paper the facts described raise serious doubts about the validity of rewetting data obtained from experiments employing external thermocouples. (U.K.)