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Sample records for outcome variables controlling

  1. Modelling variable dropout in randomised controlled trials with longitudinal outcomes: application to the MAGNETIC study.

    Science.gov (United States)

    Kolamunnage-Dona, Ruwanthi; Powell, Colin; Williamson, Paula Ruth

    2016-04-28

    Clinical trials with longitudinally measured outcomes are often plagued by missing data due to patients withdrawing or dropping out from the trial before completing the measurement schedule. The reasons for dropout are sometimes clearly known and recorded during the trial, but in many instances these reasons are unknown or unclear. Often such reasons for dropout are non-ignorable. However, the standard methods for analysing longitudinal outcome data assume that missingness is non-informative and ignore the reasons for dropout, which could result in a biased comparison between the treatment groups. In this article, as a post hoc analysis, we explore the impact of informative dropout due to competing reasons on the evaluation of treatment effect in the MAGNETIC trial, the largest randomised placebo-controlled study to date comparing the addition of nebulised magnesium sulphate to standard treatment in acute severe asthma in children. We jointly model longitudinal outcome and informative dropout process to incorporate the information regarding the reasons for dropout by treatment group. The effect of nebulised magnesium sulphate compared with standard treatment is evaluated more accurately using a joint longitudinal-competing risk model by taking account of such complexities. The corresponding estimates indicate that the rate of dropout due to good prognosis is about twice as high in the magnesium group compared with standard treatment. We emphasise the importance of identifying reasons for dropout and undertaking an appropriate statistical analysis accounting for such dropout. The joint modelling approach accounting for competing reasons for dropout is proposed as a general approach for evaluating the sensitivity of conclusions to assumptions regarding missing data in clinical trials with longitudinal outcomes. EudraCT number 2007-006227-12 . Registration date 18 Mar 2008.

  2. Assessing the variability of outcome for patients treated with localized prostate irradiation using different definitions of biochemical control

    International Nuclear Information System (INIS)

    Horwitz, Eric; Ziaja, Ellen; Vicini, Frank; Dmuchowski, Carl; Gonzalez, Jose; Stromberg, Jannifer; Brabbins, Donald; Hollander, Jay; Chen, Peter; Martinez, Alvaro

    1995-01-01

    Purpose: Biochemical control is rapidly becoming the standard to assess treatment outcome of clinically localized prostate cancer. However, no standardized definition of biochemical control has been established. We reviewed our experience treating patients with localized prostate cancer and applied 3 different commonly used definitions to estimate the variability in rates of biochemical control. Materials and Methods: Between (1(87)) and (12(91)), 480 patients with clinically localized prostate cancer received uniform treatment with external beam irradiation (RT) using localized prostate fields at William Beaumont Hospital. The median dose to the prostate was 66.6 Gy (range 58 to 70.4 Gy) through a 4 field technique. A total of 14 patients received pelvic nodal RT (median dose 45 Gy). Four hundred seventy patients had post-treatment (posttx) PSA values and 414 patients had pre-treatment (pretx) PSA values. Three different definitions of biochemical control were used: 1) Biochemical control was defined as posttx PSA nadir < 1 ng/ml within 1 year. After achieving nadir, if there were 2 consecutive increases, the patient was scored a failure at the time of the first increase; 2) Biochemical control was defined as posttx PSA nadir < 1.5 ng/ml within 1 year. After achieving nadir, if there were 2 consecutive increases, the patient was scored a failure at the time of the first increase; 3) Posttx PSA nadir < 4 ng/ml without a time limit. Once the nadir was achieved, and it did not rise above normal, the patient was considered controlled. Clinical local control was defined as no palpable prostate nodularity beyond 18 months, no new prostate nodularity, or a negative biopsy. If hormonal therapy was started, the patient was censored for biochemical failure at that time. Results: Median follow-up is 48 months (range 3 to 112 months). Pre-treatment PSA values were correlated with biochemical response using the 3 definitions of biochemical control as well as clinical local

  3. Effect of an office worksite-based yoga program on heart rate variability: outcomes of a randomized controlled trial

    Science.gov (United States)

    2013-01-01

    Background Chronic work-related stress is an independent risk factor for cardiometabolic diseases and associated mortality, particularly when compounded by a sedentary work environment. The purpose of this study was to determine if an office worksite-based hatha yoga program could improve physiological stress, evaluated via heart rate variability (HRV), and associated health-related outcomes in a cohort of office workers. Methods Thirty-seven adults employed in university-based office positions were randomized upon the completion of baseline testing to an experimental or control group. The experimental group completed a 10-week yoga program prescribed three sessions per week during lunch hour (50 min per session). An experienced instructor led the sessions, which emphasized asanas (postures) and vinyasa (exercises). The primary outcome was the high frequency (HF) power component of HRV. Secondary outcomes included additional HRV parameters, musculoskeletal fitness (i.e. push-up, side-bridge, and sit & reach tests) and psychological indices (i.e. state and trait anxiety, quality of life and job satisfaction). Results All measures of HRV failed to change in the experimental group versus the control group, except that the experimental group significantly increased LF:HF (p = 0.04) and reduced pNN50 (p = 0.04) versus control, contrary to our hypotheses. Flexibility, evaluated via sit & reach test increased in the experimental group versus the control group (p yoga sessions (n = 11) to control (n = 19) yielded the same findings, except that the high adherers also reduced state anxiety (p = 0.02) and RMSSD (p = 0.05), and tended to improve the push-up test (p = 0.07) versus control. Conclusions A 10-week hatha yoga intervention delivered at the office worksite during lunch hour did not improve HF power or other HRV parameters. However, improvements in flexibility, state anxiety and musculoskeletal fitness were noted with high adherence

  4. Assessing the variability of outcome for patients treated with localized prostate irradiation using different definitions of biochemical control

    International Nuclear Information System (INIS)

    Horwitz, Eric M.; Vicini, Frank A.; Ziaja, Ellen L.; Gonzalez, Jose; Dmuchowski, Carl F.; Stromberg, Jannifer S.; Brabbins, Donald S.; Hollander, Jay; Chen, Peter Y.; Martinez, Alvaro A.

    1996-01-01

    Purpose: Biochemical control using serial posttreatment serum prostate specific antigen (PSA) levels is being increasingly used to assess treatment efficacy for localized prostate cancer. However, no standardized definition of biochemical control has been established. We reviewed our experience treating patients with localized prostate cancer and applied three different commonly used definitions of biochemical control to determine if differences in therapeutic outcome would be observed. Methods and Materials: Between January 1987 and December 1991, 480 patients with clinically localized prostate cancer received external beam irradiation (RT) using localized prostate fields at William Beaumont Hospital. The median dose to the prostate was 66.6 Gy (range 58-70.4) using a four-field or arc technique. Pretreatment and posttreatment serum PSA levels were recorded. Over 86% (414 of 480) of patients had a pretreatment PSA level available. Three different definitions of biochemical control were used: (a) PSA nadir 20), and 5-year actuarial rates of biochemical control were calculated using the three biochemical control and one clinical local control definitions. For Group 1, 5-year actuarial rates of biochemical control were 84%, 90%, and 96% for Definitions 1-3 and clinical local control, respectively. For Group 2, 5-year actuarial control rates were 45%, 54%, 74%, and 92% for the four definitions, respectively. For Group 3, 5-year actuarial control rates were 26%, 31%, 63%, and 100% for the four definitions, respectively. For Group 4, 5-year actuarial control rates were 24%, 24%, 50%, and 100% for the four definitions, respectively. Finally, for Group 5, 5-year actuarial control rates were 5%, 14%, 15%, and 89% for the four definitions, respectively. Depending on the definition used, statistically significant differences overall in outcome rates were observed. Differences between all four definitions for all pairwise comparisons ranged from 5 to 53% (p < 0

  5. Treatment outcome and prognostic variables for local control and survival in patients receiving radical radiotherapy for urinary bladder cancer

    Energy Technology Data Exchange (ETDEWEB)

    Fokdal, Lars; Hoeyer, Morten; Maase, Hans von der [Aarhus Univ. Hospital (Denmark). Dept. of Oncology

    2004-12-01

    The aim of this retrospective study was to analyze the outcome of radical radiotherapy in 292 patients with bladder cancer and to identify prognostic factors for local control and survival. Median age was 72.3 years (range 45-83 years). Median follow up was 66 months (range 18-121 months). All patients were treated by use of a standard 3-field technique with 60 Gy in 30 fractions to the tumor and the bladder. The elective lymph nodes were treated with doses in the range from 46 Gy to 60 Gy. Complete response was obtained in 52% of the patients at 3-month control. However, 41% of all patients with an initial CR developed recurrence during follow-up. The 3-year and 5-year overall survival rate was 31% and 21%, respectively. Performance status, T-stage, macroscopic complete TURB, hydronephrosis, and serum creatinine were independent prognostic factors for overall survival and, thus, important for the selection of patients for curative intended radiotherapy. During radiotherapy acute transient side effects were recorded in 78% of the patients; severe bowel complications were recorded in 9 patients (3%). Following radiotherapy, 10 patients (3%) developed intestinal reactions requiring surgery. Three patients (1%) were cystectomized because of severe radiation reactions in the bladder. At 5-year follow-up, the actuarial risk of complications requiring surgery was 15%. Treatment-related mortality was 2%.

  6. Analysis of biopsy outcome after three-dimensional conformal radiation therapy of prostate cancer using dose-distribution variables and tumor control probability models

    International Nuclear Information System (INIS)

    Levegruen, Sabine; Jackson, Andrew; Zelefsky, Michael J.; Venkatraman, Ennapadam S.; Skwarchuk, Mark W.; Schlegel, Wolfgang; Fuks, Zvi; Leibel, Steven A.; Ling, C. Clifton

    2000-01-01

    Purpose: To investigate tumor control following three-dimensional conformal radiation therapy (3D-CRT) of prostate cancer and to identify dose-distribution variables that correlate with local control assessed through posttreatment prostate biopsies. Methods and Material: Data from 132 patients, treated at Memorial Sloan-Kettering Cancer Center (MSKCC), who had a prostate biopsy 2.5 years or more after 3D-CRT for T1c-T3 prostate cancer with prescription doses of 64.8-81 Gy were analyzed. Variables derived from the dose distribution in the PTV included: minimum dose (Dmin), maximum dose (Dmax), mean dose (Dmean), dose to n% of the PTV (Dn), where n = 1%, ..., 99%. The concept of the equivalent uniform dose (EUD) was evaluated for different values of the surviving fraction at 2 Gy (SF 2 ). Four tumor control probability (TCP) models (one phenomenologic model using a logistic function and three Poisson cell kill models) were investigated using two sets of input parameters, one for low and one for high T-stage tumors. Application of both sets to all patients was also investigated. In addition, several tumor-related prognostic variables were examined (including T-stage, Gleason score). Univariate and multivariate logistic regression analyses were performed. The ability of the logistic regression models (univariate and multivariate) to predict the biopsy result correctly was tested by performing cross-validation analyses and evaluating the results in terms of receiver operating characteristic (ROC) curves. Results: In univariate analysis, prescription dose (Dprescr), Dmax, Dmean, dose to n% of the PTV with n of 70% or less correlate with outcome (p 2 : EUD correlates significantly with outcome for SF 2 of 0.4 or more, but not for lower SF 2 values. Using either of the two input parameters sets, all TCP models correlate with outcome (p 2 , is limited because the low dose region may not coincide with the tumor location. Instead, for MSKCC prostate cancer patients with their

  7. Econometrics in outcomes research: the use of instrumental variables.

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    Newhouse, J P; McClellan, M

    1998-01-01

    We describe an econometric technique, instrumental variables, that can be useful in estimating the effectiveness of clinical treatments in situations when a controlled trial has not or cannot be done. This technique relies upon the existence of one or more variables that induce substantial variation in the treatment variable but have no direct effect on the outcome variable of interest. We illustrate the use of the technique with an application to aggressive treatment of acute myocardial infarction in the elderly.

  8. [Effects of blood glucose control on glucose variability and clinical outcomes in patients with severe acute pancreatitis in intensive care unit].

    Science.gov (United States)

    Wu, Jing; Sun, Qiuhong; Yang, Hua

    2015-05-19

    To explore the effects of blood glucose control on glucose variability and clinical outcomes in patients with severe acute pancreatitis in intensive care unit (ICU). A total of 72 ICU patients with severe acute pancreatitis were recruited and divided randomly into observation and control groups (n = 36 each). Both groups were treated conventionally. And the observation group achieved stable blood glucose at 6.1-8.3 mmol/L with intensive glucose control. The length of ICU and hospital stays, ICU mortality rate, transit operative rate, concurrent infection rate, admission blood glucose, glycosylated hemoglobin, mean insulin dose, mean blood glucose, blood glucose value standard deviation (GLUSD), glycemic liability index (GLUGLI) and mean amplitude of glycemic excursion (GLUMAGE) of two groups were compared. At the same time, the relationship between blood glucose variability, ICU mortality rate and its predictive value were analyzed by correlation analysis and receiver operating characteristic curve (ROC). The lengths of ICU and hospital stays of observation group were all significantly less than those of the control group [(11.7 ± 9.9) vs (15.9 ± 8.02) days, (21.8 ± 10.8) vs (28.2 ± 12.7) days, P blood glucose value and GLUSD of observation group were significantly lower than those of control group [(7.4 ± 1.1) vs (9.6 ± 1.2), (1.8 ± 1.0) vs (2.5 ± 1.3) mmol/L]. The differences were statistically significant (P curve analysis showed that, AUC of GLUGLI was 0.748 and 95% CI 0.551-0.965 (P glucose control in patients with severe acute pancreatitis helps reduce the blood sugar fluctuations, lower the risks of infectious complications and promote the patient rehabilitation. And GLUGLI is positively correlated with ICU mortality rate. It has good predictive values.

  9. Speed control variable rate irrigation

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    Speed control variable rate irrigation (VRI) is used to address within field variability by controlling a moving sprinkler’s travel speed to vary the application depth. Changes in speed are commonly practiced over areas that slope, pond or where soil texture is predominantly different. Dynamic presc...

  10. Outcome Controllability and Counterfactual Thinking.

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    Roese, Neal J.; Olson, James M.

    1995-01-01

    Examined impact of outcome controllability on counterfactual thoughts (thoughts of what could have been). Two studies showed that outcome controllability affected counterfactual direction: thoughts on how things could have been better were more frequent following controllable outcomes, and thoughts on how things could have been worse followed…

  11. Nurse dose: linking staffing variables to adverse patient outcomes.

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    Manojlovich, Milisa; Sidani, Souraya; Covell, Christine L; Antonakos, Cathy L

    2011-01-01

    Inconsistent findings in more than 100 studies have made it difficult to explain how variation in nurse staffing affects patient outcomes. Nurse dose, defined as the level of nurses required to provide patient care in hospital settings, draws on variables used in staffing studies to describe the influence of many staffing variables on outcomes. The aim of this study was to examine the construct validity of nurse dose by determining its association with methicillin-resistant Staphylococcus aureus (MRSA) infections and reported patient falls on a sample of inpatient adult acute care units. Staffing data came from 26 units in Ontario, Canada, and Michigan. Financial and human resource data were data sources for staffing variables. Sources of data for MRSA came from infection control departments. Incident reports were the data source for patient falls. Data analysis consisted of bivariate correlations and Poisson regression. Bivariate correlations revealed that nurse dose attributes (active ingredient and intensity) were associated significantly with both outcomes. Active ingredient (education, experience, skill mix) and intensity (full-time employees, registered nurse [RN]:patient ratio, RN hours per patient day) were significant predictors of MRSA. Coefficients for both attributes were negative and almost identical. Both attributes were significant predictors of reported patient falls, and coefficients were again negative, but coefficient sizes differed. By conceptualizing nurse and staffing variables (education, experience, skill mix, full-time employees, RN:patient ratio, RN hours per patient day) as attributes of nurse dose and by including these in the same analysis, it is possible to determine their relative influence on MRSA infections and reported patient falls.

  12. Cartas de control para monitorear variables multinomiales

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    Luz Marcela Restrepo-Tamayo

    2014-07-01

    Full Text Available Background: The control as a tool for monitoring the quality of a product, allows to study the stability of processes over time, contrasting two hypothesis, which states that the process is in stable condition and the other denies it. Its use has been massive for continuous variables but not for categorical variables, why it is imperative to design such tools for such variables. Objective: To propose two (2 control charts for variables multinomial processes based on the p-value test result for homogeneity of proportions using the chi square test for uniform processing variables and approximation Wilson - Hilferty for variables chi square. Methods: The performance of proposed charts via simulation is estimated considering a Phase II process and considering the first category increments of 2%, 4% and 6% in the control stage. Results: The multinomial control chart using Wilson-Hilferty approximation for variables chi square, from the transformation of value-p, has poor performance compared to the control charts using p-value processing and using chi-square p-value, as they have less ability to detect small changes. Conclusion: We propose two control charts to monitor multinomial variables and once studied via simulation, based on the average run length (ARL and the probability of rejecting the null hypothesis of equal proportions, we recommend the control chart using value-p, or equivalently, the control chart processing using chi square p-value.

  13. Combining clinical variables to optimize prediction of antidepressant treatment outcomes.

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    Iniesta, Raquel; Malki, Karim; Maier, Wolfgang; Rietschel, Marcella; Mors, Ole; Hauser, Joanna; Henigsberg, Neven; Dernovsek, Mojca Zvezdana; Souery, Daniel; Stahl, Daniel; Dobson, Richard; Aitchison, Katherine J; Farmer, Anne; Lewis, Cathryn M; McGuffin, Peter; Uher, Rudolf

    2016-07-01

    The outcome of treatment with antidepressants varies markedly across people with the same diagnosis. A clinically significant prediction of outcomes could spare the frustration of trial and error approach and improve the outcomes of major depressive disorder through individualized treatment selection. It is likely that a combination of multiple predictors is needed to achieve such prediction. We used elastic net regularized regression to optimize prediction of symptom improvement and remission during treatment with escitalopram or nortriptyline and to identify contributing predictors from a range of demographic and clinical variables in 793 adults with major depressive disorder. A combination of demographic and clinical variables, with strong contributions from symptoms of depressed mood, reduced interest, decreased activity, indecisiveness, pessimism and anxiety significantly predicted treatment outcomes, explaining 5-10% of variance in symptom improvement with escitalopram. Similar combinations of variables predicted remission with area under the curve 0.72, explaining approximately 15% of variance (pseudo R(2)) in who achieves remission, with strong contributions from body mass index, appetite, interest-activity symptom dimension and anxious-somatizing depression subtype. Escitalopram-specific outcome prediction was more accurate than generic outcome prediction, and reached effect sizes that were near or above a previously established benchmark for clinical significance. Outcome prediction on the nortriptyline arm did not significantly differ from chance. These results suggest that easily obtained demographic and clinical variables can predict therapeutic response to escitalopram with clinically meaningful accuracy, suggesting a potential for individualized prescription of this antidepressant drug. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Instrumental variable estimation of treatment effects for duration outcomes

    NARCIS (Netherlands)

    G.E. Bijwaard (Govert)

    2007-01-01

    textabstractIn this article we propose and implement an instrumental variable estimation procedure to obtain treatment effects on duration outcomes. The method can handle the typical complications that arise with duration data of time-varying treatment and censoring. The treatment effect we

  15. Glucose variability negatively impacts long-term functional outcome in patients with traumatic brain injury.

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    Matsushima, Kazuhide; Peng, Monica; Velasco, Carlos; Schaefer, Eric; Diaz-Arrastia, Ramon; Frankel, Heidi

    2012-04-01

    Significant glycemic excursions (so-called glucose variability) affect the outcome of generic critically ill patients but has not been well studied in patients with traumatic brain injury (TBI). The purpose of this study was to evaluate the impact of glucose variability on long-term functional outcome of patients with TBI. A noncomputerized tight glucose control protocol was used in our intensivist model surgical intensive care unit. The relationship between the glucose variability and long-term (a median of 6 months after injury) functional outcome defined by extended Glasgow Outcome Scale (GOSE) was analyzed using ordinal logistic regression models. Glucose variability was defined by SD and percentage of excursion (POE) from the preset range glucose level. A total of 109 patients with TBI under tight glucose control had long-term GOSE evaluated. In univariable analysis, there was a significant association between lower GOSE score and higher mean glucose, higher SD, POE more than 60, POE 80 to 150, and single episode of glucose less than 60 mg/dL but not POE 80 to 110. After adjusting for possible confounding variables in multivariable ordinal logistic regression models, higher SD, POE more than 60, POE 80 to 150, and single episode of glucose less than 60 mg/dL were significantly associated with lower GOSE score. Glucose variability was significantly associated with poorer long-term functional outcome in patients with TBI as measured by the GOSE score. Well-designed protocols to minimize glucose variability may be key in improving long-term functional outcome. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Blood Pressure Variability and Outcome in Patients with Acute Nonlobar Intracerebral Hemorrhage following Intensive Antihypertensive Treatment

    Directory of Open Access Journals (Sweden)

    Jin Pyeong Jeon

    2018-01-01

    Conclusions: The MAC of SBP is associated with hematoma growth, and SD and COV are correlated with 3-month poor outcome in patients with supratentorial nonlobar ICH. Therefore, sustained SBP control, with a reduction in SBP variability is essential to reinforce the beneficial effect of intensive antihypertensive treatment.

  17. Using Variable Speed Control on Pump Application

    Directory of Open Access Journals (Sweden)

    Dr.Sc. Aida Spahiu

    2012-06-01

    Full Text Available Pumps are one of the most common variable speed drive (VSD system applications and special interest has focused on improving their energy efficiency by using variable speed control instead of throttling or other less efficient flow control methods. Pumps are the single largest user of electricity in industry in the European Union, consuming 160 TWh per annum of electricity and accounting for 79 million tonnes of carbon dioxide (CO2 emissions [1]. Centrifugal pumps are the most likely pump style to provide a favorable return based on energy savings when applied with a variable speed drive. To help illustrate this, are conducted benchmark testing to document various head and flow scenarios and their corresponding effect on energy savings. Paper shows the relationship of static and friction head in the energy efficiency equation and the effect of motor, pump and VSD efficiencies. The received results are good reference points for engineers and managers of water sector in Albania to select the best prospects for maximizing efficiency and energy savings.

  18. Leg pain and psychological variables predict outcome 2-3 years after lumbar fusion surgery.

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    Abbott, Allan D; Tyni-Lenné, Raija; Hedlund, Rune

    2011-10-01

    Prediction studies testing a thorough range of psychological variables in addition to demographic, work-related and clinical variables are lacking in lumbar fusion surgery research. This prospective cohort study aimed at examining predictions of functional disability, back pain and health-related quality of life (HRQOL) 2-3 years after lumbar fusion by regressing nonlinear relations in a multivariate predictive model of pre-surgical variables. Before and 2-3 years after lumbar fusion surgery, patients completed measures investigating demographics, work-related variables, clinical variables, functional self-efficacy, outcome expectancy, fear of movement/(re)injury, mental health and pain coping. Categorical regression with optimal scaling transformation, elastic net regularization and bootstrapping were used to investigate predictor variables and address predictive model validity. The most parsimonious and stable subset of pre-surgical predictor variables explained 41.6, 36.0 and 25.6% of the variance in functional disability, back pain intensity and HRQOL 2-3 years after lumbar fusion. Pre-surgical control over pain significantly predicted functional disability and HRQOL. Pre-surgical catastrophizing and leg pain intensity significantly predicted functional disability and back pain while the pre-surgical straight leg raise significantly predicted back pain. Post-operative psychomotor therapy also significantly predicted functional disability while pre-surgical outcome expectations significantly predicted HRQOL. For the median dichotomised classification of functional disability, back pain intensity and HRQOL levels 2-3 years post-surgery, the discriminative ability of the prediction models was of good quality. The results demonstrate the importance of pre-surgical psychological factors, leg pain intensity, straight leg raise and post-operative psychomotor therapy in the predictions of functional disability, back pain and HRQOL-related outcomes.

  19. Measuring Networking as an Outcome Variable in Undergraduate Research Experiences.

    Science.gov (United States)

    Hanauer, David I; Hatfull, Graham

    2015-01-01

    The aim of this paper is to propose, present, and validate a simple survey instrument to measure student conversational networking. The tool consists of five items that cover personal and professional social networks, and its basic principle is the self-reporting of degrees of conversation, with a range of specific discussion partners. The networking instrument was validated in three studies. The basic psychometric characteristics of the scales were established by conducting a factor analysis and evaluating internal consistency using Cronbach's alpha. The second study used a known-groups comparison and involved comparing outcomes for networking scales between two different undergraduate laboratory courses (one involving a specific effort to enhance networking). The final study looked at potential relationships between specific networking items and the established psychosocial variable of project ownership through a series of binary logistic regressions. Overall, the data from the three studies indicate that the networking scales have high internal consistency (α = 0.88), consist of a unitary dimension, can significantly differentiate between research experiences with low and high networking designs, and are related to project ownership scales. The ramifications of the networking instrument for student retention, the enhancement of public scientific literacy, and the differentiation of laboratory courses are discussed. © 2015 D. I. Hanauer and G. Hatfull. CBE—Life Sciences Education © 2015 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  20. Variable-Structure Control of a Model Glider Airplane

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    Waszak, Martin R.; Anderson, Mark R.

    2008-01-01

    A variable-structure control system designed to enable a fuselage-heavy airplane to recover from spin has been demonstrated in a hand-launched, instrumented model glider airplane. Variable-structure control is a high-speed switching feedback control technique that has been developed for control of nonlinear dynamic systems.

  1. Clinical Operations Variables are Associated With Blood Pressure Outcomes.

    Science.gov (United States)

    Kressin, Nancy R; Lasser, Karen E; Paasche-Orlow, Michael; Allison, Jeroan; Ash, Arlene S; Adams, William G; Shanahan, Christopher W; Legler, Aaron; Pizer, Steven D

    2015-06-01

    Uncontrolled blood pressure (BP), among patients diagnosed and treated for the condition, remains an important clinical challenge; aspects of clinical operations could potentially be adjusted if they were associated with better outcomes. To assess clinical operations factors' effects on normalization of uncontrolled BP. Observational cohort study. Patients diagnosed with hypertension from a large urban clinical practice (2005-2009). We obtained clinical data on BP, organized by person-month, and administrative data on primary care provider (PCP) staffing. We assessed the resolution of an episode of uncontrolled BP as a function of time-varying covariates including practice-level appointment volume, individual clinicians' appointment volume, overall practice-level PCP staffing, and number of unique PCPs. Among the 7409 unique patients representing 50,403 person-months, normalization was less likely for the patients in whom the episode starts during months when the number of unique PCPs were high [the top quintile of unique PCPs was associated with a 9 percentage point lower probability of normalization (Ppercentage point reduction in the probability of normalization (P=0.01)]. Neither clinician appointment volume nor practice clinician staffing levels were significantly associated with the probability of normalization. Findings suggest that clinical operations factors can affect clinical outcomes like BP normalization, and point to the importance of considering outcome effects when organizing clinical care.

  2. Predictive Variable Gain Iterative Learning Control for PMSM

    Directory of Open Access Journals (Sweden)

    Huimin Xu

    2015-01-01

    Full Text Available A predictive variable gain strategy in iterative learning control (ILC is introduced. Predictive variable gain iterative learning control is constructed to improve the performance of trajectory tracking. A scheme based on predictive variable gain iterative learning control for eliminating undesirable vibrations of PMSM system is proposed. The basic idea is that undesirable vibrations of PMSM system are eliminated from two aspects of iterative domain and time domain. The predictive method is utilized to determine the learning gain in the ILC algorithm. Compression mapping principle is used to prove the convergence of the algorithm. Simulation results demonstrate that the predictive variable gain is superior to constant gain and other variable gains.

  3. Variable pattern contamination control under positive pressure

    International Nuclear Information System (INIS)

    Philippi, H.M.

    1997-01-01

    Airborne contamination control in nuclear and biological laboratories is traditionally achieved by directing the space ventilation air at subatmospheric pressures in one fixed flow pattern. However, biological and nuclear contamination flow control in the new Biological Research Facility, to be commissioned at the Chalk River Laboratories in 1996, will have the flexibility to institute a number of contamination control patterns, all achieved at positive (above atmospheric) pressures. This flexibility feature, made possible by means of a digitally controlled ventilation system, changes the facility ventilation system from being a relatively rigid building service operated by plant personnel into a flexible building service which can be operated by the facility research personnel. This paper focuses on and describes the application of these unique contamination control features in the design of the new Biological Research Facility. 3 refs., 7 figs

  4. Variable pattern contamination control under positive pressure

    Energy Technology Data Exchange (ETDEWEB)

    Philippi, H.M. [Chalk River Labs., Ontario (Canada)

    1997-08-01

    Airborne contamination control in nuclear and biological laboratories is traditionally achieved by directing the space ventilation air at subatmospheric pressures in one fixed flow pattern. However, biological and nuclear contamination flow control in the new Biological Research Facility, to be commissioned at the Chalk River Laboratories in 1996, will have the flexibility to institute a number of contamination control patterns, all achieved at positive (above atmospheric) pressures. This flexibility feature, made possible by means of a digitally controlled ventilation system, changes the facility ventilation system from being a relatively rigid building service operated by plant personnel into a flexible building service which can be operated by the facility research personnel. This paper focuses on and describes the application of these unique contamination control features in the design of the new Biological Research Facility. 3 refs., 7 figs.

  5. On the functional aspects of variability in postural control

    NARCIS (Netherlands)

    Van Emmerik, Richard E.A.; Van Wegen, Erwin E.H.

    2002-01-01

    Current research in nonlinear dynamics and chaos theory has challenged traditional perspectives that associate high variability with performance decrement and pathology. It is argued that variability can play a functional role in postural control and that reduction of variability is associated with

  6. The television, school, and family smoking prevention and cessation project. VIII. Student outcomes and mediating variables.

    Science.gov (United States)

    Flay, B R; Miller, T Q; Hedeker, D; Siddiqui, O; Britton, C F; Brannon, B R; Johnson, C A; Hansen, W B; Sussman, S; Dent, C

    1995-01-01

    This paper presents the student outcomes of a large-scale, social-influences-based, school and media-based tobacco use prevention and cessation project in Southern California. The study provided an experimental comparison of classroom delivery with television delivery and the combination of the two in a 2 x 2 plus 1 design. Schools were randomly assigned to conditions. Control groups included "treatment as usual" and an "attention control" with the same outcome expectancies as the treatment conditions. Students were surveyed twice in grade 7 and once in each of grades 8 and 9. The interventions occurred during grade 7. We observed significant effects on mediating variables such as knowledge and prevalence estimates, and coping effort. The knowledge and prevalence estimates effects decayed partially but remained significant up to a 2-year follow-up. The coping effort effect did not persist at follow-ups. There were significant main effects of both classroom training and TV programming on knowledge and prevalence estimates and significant interactions of classroom and TV programming on knowledge (negative), disapproval of parental smoking, and coping effort. There were no consistent program effects on refusal/self-efficacy, smoking intentions, or behavior. Previous reports demonstrated successful development and pilot testing of program components and measures and high acceptance of the program by students and parents. The lack of behavioral effects may have been the result of imperfect program implementation or low base rates of intentions and behavior.

  7. Symmetric voltage-controlled variable resistance

    Science.gov (United States)

    Vanelli, J. C.

    1978-01-01

    Feedback network makes resistance of field-effect transistor (FET) same for current flowing in either direction. It combines control voltage with source and load voltages to give symmetric current/voltage characteristics. Since circuit produces same magnitude output voltage for current flowing in either direction, it introduces no offset in presense of altering polarity signals. It is therefore ideal for sensor and effector circuits in servocontrol systems.

  8. Control of a hydraulically actuated continuously variable transmission

    NARCIS (Netherlands)

    Pesgens, M.F.M.; Vroemen, B.G.; Stouten, B.; Veldpaus, F.E.; Steinbuch, M.

    2006-01-01

    Vehicular drivelines with hierarchical powertrain control require good component controller tracking, enabling the main controller to reach the desired goals. This paper focuses on the development of a transmission ratio controller for a hydraulically actuated metal push-belt continuously variable

  9. Control approach development for variable recruitment artificial muscles

    Science.gov (United States)

    Jenkins, Tyler E.; Chapman, Edward M.; Bryant, Matthew

    2016-04-01

    This study characterizes hybrid control approaches for the variable recruitment of fluidic artificial muscles with double acting (antagonistic) actuation. Fluidic artificial muscle actuators have been explored by researchers due to their natural compliance, high force-to-weight ratio, and low cost of fabrication. Previous studies have attempted to improve system efficiency of the actuators through variable recruitment, i.e. using discrete changes in the number of active actuators. While current variable recruitment research utilizes manual valve switching, this paper details the current development of an online variable recruitment control scheme. By continuously controlling applied pressure and discretely controlling the number of active actuators, operation in the lowest possible recruitment state is ensured and working fluid consumption is minimized. Results provide insight into switching control scheme effects on working fluids, fabrication material choices, actuator modeling, and controller development decisions.

  10. Variability in the Initial Costs of Care and One-Year Outcomes of Observation Services

    Directory of Open Access Journals (Sweden)

    Abbass, Ibrahim

    2015-05-01

    Full Text Available Introduction: The use of observation units (OUs following emergency departments (ED visits as a model of care has increased exponentially in the last decade. About one-third of U.S. hospitals now have OUs within their facilities. While their use is associated with lower costs and comparable level of care compared to inpatient units, there is a wide variation in OUs characteristics and operational procedures. The objective of this research was to explore the variability in the initial costs of care of placing patients with non-specific chest pain in observation units (OUs and the one-year outcomes. Methods: The author retrospectively investigated medical insurance claims of 22,962 privately insured patients (2009-2011 admitted to 41 OUs. Outcomes included the one-year chest pain/cardiovascular related costs and primary and secondary outcomes. Primary outcomes included myocardial infarction, congestive heart failure, stroke or cardiac arrest, while secondary outcomes included revascularization procedures, ED revisits for angina pectoris or chest pain and hospitalization due to cardiovascular diseases. The author aggregated the adjusted costs and prevalence rates of outcomes for patients over OUs, and computed the weighted coefficients of variation (WCV to compare variations across OUs. Results: There was minimal variability in the initial costs of care (WCV=2.2%, while the author noticed greater variability in the outcomes. Greater variability were associated with the adjusted cardiovascular-related costs of medical services (WCV=17.6% followed by the adjusted prevalence odds ratio of patients experiencing primary outcomes (WCV=16.3% and secondary outcomes (WCV=10%. Conclusion: Higher variability in the outcomes suggests the need for more standardization of the observation services for chest pain patients. [West J Emerg Med. 2015;16(3:395–400.

  11. Variable setpoint as a relaxing component in physiological control.

    Science.gov (United States)

    Risvoll, Geir B; Thorsen, Kristian; Ruoff, Peter; Drengstig, Tormod

    2017-09-01

    Setpoints in physiology have been a puzzle for decades, and especially the notion of fixed or variable setpoints have received much attention. In this paper, we show how previously presented homeostatic controller motifs, extended with saturable signaling kinetics, can be described as variable setpoint controllers. The benefit of a variable setpoint controller is that an observed change in the concentration of the regulated biochemical species (the controlled variable) is fully characterized, and is not considered a deviation from a fixed setpoint. The variation in this biochemical species originate from variation in the disturbances (the perturbation), and thereby in the biochemical species representing the controller (the manipulated variable). Thus, we define an operational space which is spanned out by the combined high and low levels of the variations in (1) the controlled variable, (2) the manipulated variable, and (3) the perturbation. From this operational space, we investigate whether and how it imposes constraints on the different motif parameters, in order for the motif to represent a mathematical model of the regulatory system. Further analysis of the controller's ability to compensate for disturbances reveals that a variable setpoint represents a relaxing component for the controller, in that the necessary control action is reduced compared to that of a fixed setpoint controller. Such a relaxing component might serve as an important property from an evolutionary point of view. Finally, we illustrate the principles using the renal sodium and aldosterone regulatory system, where we model the variation in plasma sodium as a function of salt intake. We show that the experimentally observed variations in plasma sodium can be interpreted as a variable setpoint regulatory system. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  12. Pitch Angle Control for Variable Speed Wind Turbines

    DEFF Research Database (Denmark)

    Chen, Zhe; Zhang, Jianzhong; Cheng, M

    2008-01-01

    Pitch angle control is the most common means for adjusting the aerodynamic torque of the wind turbine when wind speed is above rated speed and various controlling variables may be chosen, such as wind speed, generator speed and generator power. As conventional pitch control usually use PI...... controller, the mathematical model of the system should be known well. A fuzzy logic pitch angle controller is developed in this paper, in which it does not need well known about the system and the mean wind speed is used to compensate the non-linear sensitivity. The fuzzy logic control strategy may have...... the potential when the system contains strong non-linearity, such as wind turbulence is strong, or the control objectives include fatigue loads. The design of the fuzzy logic controller and the comparisons with conversional pitch angle control strategies with various controlling variables are carried out...

  13. Variable structure unit vector control of electric power generation ...

    African Journals Online (AJOL)

    A variable structure Automatic Generation Control (VSAGC) scheme is proposed in this paper for the control of a single area power system model dominated by steam powered electric generating plants. Unlike existing, VSAGC scheme where the selection of the control function is based on a trial and error procedure, the ...

  14. Intelligent control for large-scale variable speed variable pitch wind turbines

    Institute of Scientific and Technical Information of China (English)

    Xinfang ZHANG; Daping XU; Yibing LIU

    2004-01-01

    Large-scale wind turbine generator systems have strong nonlinear multivariable characteristics with many uncertain factors and disturbances.Automatic control is crucial for the efficiency and reliability of wind turbines.On the basis of simplified and proper model of variable speed variable pitch wind turbines,the effective wind speed is estimated using extended Kalman filter.Intelligent control schemes proposed in the paper include two loops which operate in synchronism with each other.At below-rated wind speed,the inner loop adopts adaptive fuzzy control based on variable universe for generator torque regulation to realize maximum wind energy capture.At above-rated wind speed, a controller based on least square support vector machine is proposed to adjust pitch angle and keep rated output power.The simulation shows the effectiveness of the intelligent control.

  15. Limit cycles and stiffness control with variable stiffness actuators

    NARCIS (Netherlands)

    Carloni, Raffaella; Marconi, L.

    2012-01-01

    Variable stiffness actuators realize highly dynamic systems, whose inherent mechanical compliance can be properly exploited to obtain a robust and energy-efficient behavior. The paper presents a control strategy for variable stiffness actuators with the primarily goal of tracking a limit cycle

  16. Controlled outcome studies of child clinical hypnosis.

    Science.gov (United States)

    Adinolfi, Barbara; Gava, Nicoletta

    2013-09-01

    Background Hypnosis is defined as "as an interaction in which the hypnotist uses suggested scenarios ("suggestions") to encourage a person's focus of attention to shift towards inner experiences". Aim of the work The focus of this review is to summarize the findings of controlled outcome studies investigating the potential of clinical hypnosis in pediatric populations. We will examine the following themes: anesthesia, acute and chronic pain, chemotherapy-related distress, along with other specific medical issues. Results Hypnosis is an effective method to reduce pain and anxiety before, during and after the administration of anesthetics, during local dental treatments, invasive medical procedures and in burn children. Hypnosis can be successfully used to manage recurrent headaches, abdominal pain, irritable bowel syndrome and chemotherapy-related distress. Hypnosis has an important role in managing symptoms and improving the quality of life of children suffering from asthma and cystic fibrosis and in facilitating the treatment of insomnia in school-age children. Finally, hypnosis can be effectively used for the treatment of some habitual disorders such as nocturnal enuresis and dermatologic conditions, including atopic dermatitis and chronic eczema Conclusions Clinical hypnosis seems to be a useful, cheap and side-effects free tool to manage fear, pain and several kinds of stressful experiences in pediatric populations. Children who receive self-hypnosis trainings achieve significantly greater improvements in their physical health, quality of life, and self-esteem.

  17. Active surge control for variable speed axial compressors.

    Science.gov (United States)

    Lin, Shu; Yang, Chunjie; Wu, Ping; Song, Zhihuan

    2014-09-01

    This paper discusses active surge control in variable speed axial compressors. A compression system equipped with a variable area throttle is investigated. Based on a given compressor model, a fuzzy logic controller is designed for surge control and a proportional speed controller is used for speed control. The fuzzy controller uses measurements of the change of pressure rise as well as the change of mass flow to determine the throttle opening. The presented approach does not require the knowledge of system equilibrium or the surge line. Numerical simulations show promising results. The proposed fuzzy logic controller performs better than a backstepping controller and is capable to suppress surge at different operating points. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  18. Variable speed control for Vertical Axis Wind Turbine

    DEFF Research Database (Denmark)

    Galinos, Christos; Larsen, Torben J.

    A robust variable speed control for vertical axis wind turbine applications is implemented. It is a PI rotor speed controller based on an induction generator model operated at variable frequency. The generator dynamics are approximated by a first order differential equation with a prescribed slip....... In order to allow variability in the rotor speed an inverter is assumed which changes the nominal generator speed. Below rated power the optimum tip speed ratio is tracked, while above the power is constrained to rated. The wind speed which is needed in the control it is considered as a known signal...... the Inflow project. The investigation of the VAWT performance under different control parameters such as the PI gains has been performed by Christos Galinos. Deterministic and turbulent wind speed steps of 2 m/s from 6 m/s to 24 m/s and back to 12 m/s are applied. The controller gives smooth transient...

  19. Glucose control and cardiovascular outcomes: reorienting approach.

    Science.gov (United States)

    Khardori, Romesh; Nguyen, Diep D

    2012-01-01

    Cardiovascular disease accounts for nearly 70% of morbidity and mortality in patients with diabetes mellitus. Strides made in diabetes care have indeed helped prevent or reduce the burden of microvascular complications in both type 1 and type 2 diabetes. However, the same cannot be said about macrovascular disease in diabetes. Several prospective trials so far have failed to provide conclusive evidence of the superiority of glycemic control in reducing macrovascular complications or death rates in people with advanced disease or those with long duration of diabetes. There are trends that suggest that benefits are restricted to those with lesser burden and shorter duration of disease. Furthermore, it is also suggested that benefits might accrue but it would take a longer time to manifest. Clinicians are faced with the challenge to decide how to triage patients for intensified care vs less intense care. This review focuses on evidence and attempts to provide a balanced view of the literature that has radically affected how physicians treat patients with macrovascular disease. It also takes cognizance of the fact that the natural course of the disease may be changing as well, possibly related to better overall awareness and possibly improved access to information about better individual healthcare. The review further takes note of some hard held notions about the pathobiology of the disease that must be interpreted with caution in light of new and emerging data. In light of recent developments ADA and EASD have taken step to provide some guidance to clinicians through a joint position statement. A lot more research would be required to figure out how best to manage macrovascular disease in diabetes mellitus. Glucocentric stance would need to be reconsidered, and attention paid to concurrent multifactorial interventions that seem to be effective in reducing vascular outcomes.

  20. The Effects of Job Autonomy on Work Outcomes: Self Efficacy as an Intervening Variable

    OpenAIRE

    Susanti Saragih

    2011-01-01

    The purpose of this research was to examine the relationship between job autonomy and work outcomes (job performance, job satisfaction and job stress), self efficacy as a mediating variable. This research also investigated the impact of job satisfaction on job performance and job stress on job performance. Va-riables in this research were measured via a survey of 190 banking salespersons in D.I. Yogyakarta and Solo. Structural Equation Modeling (SEM) were used to examine the effects of job au...

  1. FPGA implementation of high-frequency multiple PWM for variable voltage variable frequency controller

    Energy Technology Data Exchange (ETDEWEB)

    Boumaaraf, Abdelâali, E-mail: aboumaaraf@yahoo.fr [Université Abbès Laghrour, Laboratoire des capteurs, Instrumentations et procédés (LCIP), Khenchela (Algeria); University of Farhat Abbas Setif1, Sétif, 19000 (Algeria); Mohamadi, Tayeb [University of Farhat Abbas Setif1, Sétif, 19000 (Algeria); Gourmat, Laïd [Université Abbès Laghrour, Khenchela, 40000 (Algeria)

    2016-07-25

    In this paper, we present the FPGA implementation of the multiple pulse width modulation (MPWM) signal generation with repetition of data segments, applied to the variable frequency variable voltage systems and specially at to the photovoltaic water pumping system, in order to generate a signal command very easily between 10 Hz to 60 Hz with a small frequency and reduce the cost of the control system.

  2. Variable reporting of functional outcomes and return to play in superior labrum anterior and posterior tear.

    Science.gov (United States)

    Steinhaus, Michael E; Makhni, Eric C; Lieber, Adam C; Kahlenberg, Cynthia A; Gulotta, Lawrence V; Romeo, Anthony A; Verma, Nikhil N

    2016-11-01

    Outcomes assessments after superior labrum anterior and posterior (SLAP) tear/repair are highly varied, making it difficult to draw comparisons across the literature. This study examined the inconsistency in outcomes reporting in the SLAP tear literature. We hypothesize that there is significant variability in outcomes reporting and that although most studies may report return to play, time to return reporting will be highly variable. The PubMed, Medline, Scopus, and Embase databases were systematically reviewed for studies from January 2000 to December 2014 reporting outcomes after SLAP tear/repair. Two reviewers assessed each study, and those meeting inclusion criteria were examined for pertinent data. Outcomes included objective (range of motion, strength, clinical examinations, and imaging) and subjective (patient-reported outcomes, satisfaction, activities of daily living, and return to play) measures. Of the 56 included studies, 43% documented range of motion, 14% reported strength, and 16% noted postoperative imaging. There was significant variation in use of patient-reported outcomes measures, with the 3 most commonly noted measures reported in 20% to 55% of studies. Return to play was noted in 75% of studies, and 23% reported time to return, with greater rates in elite athletes. Eleven studies (20%) did not report follow-up or noted data with <12 months of follow-up. The SLAP literature is characterized by substantial variability in outcomes reporting, with time to return to play noted in few studies. Efforts to standardize outcomes reporting would facilitate comparisons across the literature and improve our understanding of the prognosis of this injury. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  3. Dynamics of melanoma tumor therapy with vesicular stomatitis virus: explaining the variability in outcomes using mathematical modeling.

    Science.gov (United States)

    Rommelfanger, D M; Offord, C P; Dev, J; Bajzer, Z; Vile, R G; Dingli, D

    2012-05-01

    Tumor selective, replication competent viruses are being tested for cancer gene therapy. This approach introduces a new therapeutic paradigm due to potential replication of the therapeutic agent and induction of a tumor-specific immune response. However, the experimental outcomes are quite variable, even when studies utilize highly inbred strains of mice and the same cell line and virus. Recognizing that virotherapy is an exercise in population dynamics, we utilize mathematical modeling to understand the variable outcomes observed when B16ova malignant melanoma tumors are treated with vesicular stomatitis virus in syngeneic, fully immunocompetent mice. We show how variability in the initial tumor size and the actual amount of virus delivered to the tumor have critical roles on the outcome of therapy. Virotherapy works best when tumors are small, and a robust innate immune response can lead to superior tumor control. Strategies that reduce tumor burden without suppressing the immune response and methods that maximize the amount of virus delivered to the tumor should optimize tumor control in this model system.

  4. Automatic Welding Control Using a State Variable Model.

    Science.gov (United States)

    1979-06-01

    A-A10 610 NAVEAL POSTGRADUATE SCH4O.M CEAY CA0/ 13/ SAUTOMATIC WELDING CONTROL USING A STATE VARIABLE MODEL.W()JUN 79 W V "my UNCLASSIFIED...taverse Drive Unit // Jbint Path /Fixed Track 34 (servomotor positioning). Additional controls of heave (vertical), roll (angular rotation about the

  5. In search of control variables : A systems approach

    NARCIS (Netherlands)

    Dalenoort, GJ

    1997-01-01

    Motor processes cannot be modeled by a single (unified) model. Instead, a number of models at different levels of description are needed. The concepts of control and control variable only make sense at the functional level. A clear distinction must be made between external models and internal

  6. Exporting Variables in a Hierarchically Distributed Control System

    Energy Technology Data Exchange (ETDEWEB)

    Chamizo Llatas, M

    1995-07-01

    We describe the Remote Variable Access Service (RVAS), a network service developed and used in the distributed control and monitoring system of the TJ-II Heliac, which is under construction at CIEMAT (Madrid, Spain) and devoted to plasma studies in the nuclear fusion field. The architecture of the TJ-II control system consists of one central Sun workstation Sparc 10 and several autonomous subsystems based on VME crates with embedded processors running the OS-9 (V.24) real time operating system. The RVAS service allows state variables in local control processes running in subsystems to be exported to remote processes running in the central control workstation. Thus we extend the concept of exporting of file systems in UNIX machines to variables in processes running in different machines. (Author) 6 refs.

  7. Exporting Variables in a Hierarchically Distributed Control System

    International Nuclear Information System (INIS)

    Diaz Martin; Martinez Laso, L.

    1995-01-01

    We describe the Remote Variable Access Service (RVAS), a network service developed and use in the distributed control and monitoring system of the TJ-II Heliac, which is under construction at CIEMAT (Madrid, Spain) and devoted to plasma studies in the nuclear fusion field. The architecture of the TJ-II control system consists of one central Sun workstation Sparc 10 and several autonomous subsystems based on VME crates with embedded processors running the os-9 (V.24) real time operating system. The RVAS service allows state variables in local control processes running in subsystems to be exported to remote processes running in the central control workstation. Thus we extend the concept of exporting of file systems in UNIX machines to variables in processes running in different machines. (Author)

  8. Exporting Variables in a Hierarchically Distributed Control System

    International Nuclear Information System (INIS)

    Chamizo Llatas, M.

    1995-01-01

    We describe the Remote Variable Access Service (RVAS), a network service developed and used in the distributed control and monitoring system of the TJ-II Heliac, which is under construction at CIEMAT (Madrid, Spain) and devoted to plasma studies in the nuclear fusion field. The architecture of the TJ-II control system consists of one central Sun workstation Sparc 10 and several autonomous subsystems based on VME crates with embedded processors running the OS-9 (V.24) real time operating system. The RVAS service allows state variables in local control processes running in subsystems to be exported to remote processes running in the central control workstation. Thus we extend the concept of exporting of file systems in UNIX machines to variables in processes running in different machines. (Author) 6 refs

  9. High Variability in Outcome Reporting Patterns in High-Impact ACL Literature.

    Science.gov (United States)

    Makhni, Eric C; Padaki, Ajay S; Petridis, Petros D; Steinhaus, Michael E; Ahmad, Christopher S; Cole, Brian J; Bach, Bernard R

    2015-09-16

    ACL (anterior cruciate ligament) reconstruction is one of the most commonly performed and studied procedures in modern sports medicine. A multitude of objective and subjective patient outcome measures exists; however, nonstandardized reporting patterns of these metrics may create challenges in objectively analyzing pooled results from different studies. The goal of this study was to document the variability in outcome reporting patterns in high-impact orthopaedic studies of ACL reconstruction. All clinical studies pertaining to ACL reconstruction in four high-impact-factor orthopaedic journals over a five-year period were reviewed. Biomechanical, basic science, and imaging studies were excluded, as were studies with fewer than fifty patients, yielding 119 studies for review. Incorporation of various objective and subjective outcomes was noted for each study. Substantial variability in reporting of both objective and subjective measures was noted in the study cohort. Although a majority of studies reported instrumented laxity findings, there was substantial variability in the type and method of laxity reporting. Most other objective outcomes, including range of motion, strength, and complications, were reported in <50% of all studies. Return to pre-injury level of activity was infrequently reported (24% of studies), as were patient satisfaction and pain assessment following surgery (8% and 13%, respectively). Of the patient-reported outcomes, the International Knee Documentation Committee (IKDC), Lysholm, and Tegner scores were most often reported (71%, 63%, and 42%, respectively). Substantial variability in outcome reporting patterns exists among high-impact studies of ACL reconstruction. Such variability may create challenges in interpreting results and pooling them across different studies. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

  10. Does psychotherapy work with school-aged youth? A meta-analytic examination of moderator variables that influence therapeutic outcomes.

    Science.gov (United States)

    Fedewa, Alicia L; Ahn, Soyeon; Reese, Robert J; Suarez, Marietta M; Macquoid, Ahjane; Davis, Matthew C; Prout, H Thompson

    2016-06-01

    The present study is a quantitative synthesis of the available literature to investigate the efficacy of psychotherapy for children's mental health outcomes. In particular, this study focuses on potential moderating variables-study design, treatment, client, and therapist characteristics-that may influence therapeutic outcomes for youth but have not been thoroughly accounted for in prior meta-analytic studies. An electronic search of relevant databases resulted in 190 unpublished and published studies that met criteria for inclusion in the analysis. Effect sizes differed by study design. Pre-post-test designs resulted in absolute magnitudes of treatment effects ranging from |-0.02| to |-0.76| while treatment versus control group comparison designs resulted in absolute magnitudes of treatment effects ranging from |-0.14| to |-2.39|. Changes in youth outcomes larger than 20% were found, irrespective of study design, for outcomes focused on psychosomatization (29% reduction), school attendance (25% increase), and stress (48% reduction). The magnitude of changes after psychotherapy ranged from 6% (externalizing problems) to 48% (stress). Several moderator variables significantly influenced psychotherapy treatment effect sizes, including frequency and length of treatment as well as treatment format. However, results did not support the superiority of a single type of intervention for most outcomes. Implications for therapy with school-aged youth and future research are discussed. Copyright © 2016 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

  11. Control of variable speed variable pitch wind turbine based on a disturbance observer

    Science.gov (United States)

    Ren, Haijun; Lei, Xin

    2017-11-01

    In this paper, a novel sliding mode controller based on disturbance observer (DOB) to optimize the efficiency of variable speed variable pitch (VSVP) wind turbine is developed and analyzed. Due to the highly nonlinearity of the VSVP system, the model is linearly processed to obtain the state space model of the system. Then, a conventional sliding mode controller is designed and a DOB is added to estimate wind speed. The proposed control strategy can successfully deal with the random nature of wind speed, the nonlinearity of VSVP system, the uncertainty of parameters and external disturbance. Via adding the observer to the sliding mode controller, it can greatly reduce the chattering produced by the sliding mode switching gain. The simulation results show that the proposed control system has the effectiveness and robustness.

  12. Adaptive Torque Control of Variable Speed Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, K. E.

    2004-08-01

    The primary focus of this work is a new adaptive controller that is designed to resemble the standard non-adaptive controller used by the wind industry for variable speed wind turbines below rated power. This adaptive controller uses a simple, highly intuitive gain adaptation law designed to seek out the optimal gain for maximizing the turbine's energy capture. It is designed to work even in real, time-varying winds.

  13. Education and Health Matters: School Nurse Interventions, Student Outcomes, and School Variables

    Science.gov (United States)

    Wolfe, Linda C.

    2013-01-01

    This paper presents findings from a quantitative, correlational study that examined selected school nursing services, student academic outcomes, and school demographics. Ex post facto data from the 2011-2012 school year of Delaware public schools were used in the research. The selected variables were school nurse interventions provided to students…

  14. The Moderating Role of Power Distance on the Relationship between Employee Participation and Outcome Variables

    Science.gov (United States)

    Rafiei, Sima; Pourreza, Abolghasem

    2013-01-01

    Background: Many organisations have realised the importance of human resource for their competitive advantage. Empowering employees is therefore essential for organisational effectiveness. This study aimed to investigate the relationship between employee participation with outcome variables such as organisational commitment, job satisfaction, perception of justice in an organisation and readiness to accept job responsibilities. It further examined the impact of power distance on the relationship between participation and four outcome variables. Methods: This was a cross sectional study with a descriptive research design conducted among employees and managers of hospitals affiliated with Tehran University of Medical Sciences, Tehran, Iran. A questionnaire as a main procedure to gather data was developed, distributed and collected. Descriptive statistics, Pearson correlation coefficient and moderated multiple regression were used to analyse the study data. Results: Findings of the study showed that the level of power distance perceived by employees had a significant relationship with employee participation, organisational commitment, job satisfaction, perception of justice and readiness to accept job responsibilities. There was also a significant relationship between employee participation and four outcome variables. The moderated multiple regression results supported the hypothesis that power distance had a significant effect on the relationship between employee participation and four outcome variables. Conclusion: Organisations in which employee empowerment is practiced through diverse means such as participating them in decision making related to their field of work, appear to have more committed and satisfied employees with positive perception toward justice in the organisational interactions and readiness to accept job responsibilities. PMID:24596840

  15. The Moderating Role of Power Distance on the Relationship between Employee Participation and Outcome Variables.

    Science.gov (United States)

    Rafiei, Sima; Pourreza, Abolghasem

    2013-06-01

    Many organisations have realised the importance of human resource for their competitive advantage. Empowering employees is therefore essential for organisational effectiveness. This study aimed to investigate the relationship between employee participation with outcome variables such as organisational commitment, job satisfaction, perception of justice in an organisation and readiness to accept job responsibilities. It further examined the impact of power distance on the relationship between participation and four outcome variables. This was a cross sectional study with a descriptive research design conducted among employees and managers of hospitals affiliated with Tehran University of Medical Sciences, Tehran, Iran. A questionnaire as a main procedure to gather data was developed, distributed and collected. Descriptive statistics, Pearson correlation coefficient and moderated multiple regression were used to analyse the study data. Findings of the study showed that the level of power distance perceived by employees had a significant relationship with employee participation, organisational commitment, job satisfaction, perception of justice and readiness to accept job responsibilities. There was also a significant relationship between employee participation and four outcome variables. The moderated multiple regression results supported the hypothesis that power distance had a significant effect on the relationship between employee participation and four outcome variables. Organisations in which employee empowerment is practiced through diverse means such as participating them in decision making related to their field of work, appear to have more committed and satisfied employees with positive perception toward justice in the organisational interactions and readiness to accept job responsibilities.

  16. The Moderating Role of Power Distance on the Relationship between Employee Participation and Outcome Variables

    Directory of Open Access Journals (Sweden)

    Abolghasem Pourreza

    2013-05-01

    Full Text Available Background Many organisations have realised the importance of human resource for their competitive advantage. Empowering employees is therefore essential for organisational effectiveness. This study aimed to investigate the relationship between employee participation with outcome variables such as organisational commitment, job satisfaction, perception of justice in an organisation and readiness to accept job responsibilities. It further examined the impact of power distance on the relationship between participation and four outcome variables. Methods This was a cross sectional study with a descriptive research design conducted among employees and managers of hospitals affiliated with Tehran University of Medical Sciences, Tehran, Iran. A questionnaire as a main procedure to gather data was developed, distributed and collected. Descriptive statistics, Pearson correlation coefficient and moderated multiple regression were used to analyse the study data. Results Findings of the study showed that the level of power distance perceived by employees had a significant relationship with employee participation, organisational commitment, job satisfaction, perception of justice and readiness to accept job responsibilities. There was also a significant relationship between employee participation and four outcome variables. The moderated multiple regression results supported the hypothesis that power distance had a significant effect on the relationship between employee participation and four outcome variables. Conclusion Organisations in which employee empowerment is practiced through diverse means such as participating them in decision making related to their field of work, appear to have more committed and satisfied employees with positive perception toward justice in the organisational interactions and readiness to accept job responsibilities.

  17. Modelling for Fuel Optimal Control of a Variable Compression Engine

    OpenAIRE

    Nilsson, Ylva

    2007-01-01

    Variable compression engines are a mean to meet the demand on lower fuel consumption. A high compression ratio results in high engine efficiency, but also increases the knock tendency. On conventional engines with fixed compression ratio, knock is avoided by retarding the ignition angle. The variable compression engine offers an extra dimension in knock control, since both ignition angle and compression ratio can be adjusted. The central question is thus for what combination of compression ra...

  18. Turbo-generator control with variable valve actuation

    Science.gov (United States)

    Vuk, Carl T [Denver, IA

    2011-02-22

    An internal combustion engine incorporating a turbo-generator and one or more variably activated exhaust valves. The exhaust valves are adapted to variably release exhaust gases from a combustion cylinder during a combustion cycle to an exhaust system. The turbo-generator is adapted to receive exhaust gases from the exhaust system and rotationally harness energy therefrom to produce electrical power. A controller is adapted to command the exhaust valve to variably open in response to a desired output for the turbo-generator.

  19. Observer Backstepping Control for Variable Speed Wind Turbine

    DEFF Research Database (Denmark)

    Galeazzi, Roberto; Gryning, Mikkel Peter Sidoroff; Blanke, Mogens

    2013-01-01

    . The nonlinear controller aims at regulating the generator torque such that an optimal tip-speed ratio can be obtained. Simply relying on the measured rotor angular velocity the proposed observer backstepping controller guarantees global asymptotic tracking of the desired trajectory while maintaining a globally......This paper presents an observer backstepping controller as feasible solution to variable speed control of wind turbines to maximize wind power capture when operating between cut-in and rated wind speeds. The wind turbine is modeled as a two-mass drive-train system controlled by the generator torque...

  20. Assessing the Impact of Socioeconomic Variables on Small Area Variations in Suicide Outcomes in England

    Directory of Open Access Journals (Sweden)

    Peter Congdon

    2012-12-01

    Full Text Available Ecological studies of suicide and self-harm have established the importance of area variables (e.g., deprivation, social fragmentation in explaining variations in suicide risk. However, there are likely to be unobserved influences on risk, typically spatially clustered, which can be modeled as random effects. Regression impacts may be biased if no account is taken of spatially structured influences on risk. Furthermore a default assumption of linear effects of area variables may also misstate or understate their impact. This paper considers variations in suicide outcomes for small areas across England, and investigates the impact on them of area socio-economic variables, while also investigating potential nonlinearity in their impact and allowing for spatially clustered unobserved factors. The outcomes are self-harm hospitalisations and suicide mortality over 6,781 Middle Level Super Output Areas.

  1. High glucose variability is associated with poor neurodevelopmental outcomes in neonatal hypoxic ischemic encephalopathy.

    Science.gov (United States)

    Al Shafouri, N; Narvey, M; Srinivasan, G; Vallance, J; Hansen, G

    2015-01-01

    In neonatal hypoxic ischemic encephalopathy (HIE), hypo- and hyperglycemia have been associated with poor outcomes. However, glucose variability has not been reported in this population. To examine the association between serum glucose variability within the first 24 hours and two-year neurodevelopmental outcomes in neonates cooled for HIE. In this retrospective cohort study, glucose, clinical and demographic data were documented from 23 term newborns treated with whole body therapeutic hypothermia. Severe neurodevelopmental outcomes from planned two-year assessments were defined as the presence of any one of the following: Gross Motor Function Classification System levels 3 to 5, Bayley III Motor Standard Score neurodevelopmental outcomes from 8 of 23 patients were considered severe, and this group demonstrated a significant increase of mean absolute glucose (MAG) change (-0.28 to -0.03, 95% CI, p = 0.032). There were no significant differences between outcome groups with regards to number of patients with hyperglycemic means, one or multiple hypo- or hyperglycemic measurement(s). There were also no differences between both groups with mean glucose, although mean glucose standard deviation was approaching significance. Poor neurodevelopmental outcomes in whole body cooled HIE neonates are significantly associated with MAG changes. This information may be relevant for prognostication and potential management strategies.

  2. Regulating task-monitoring systems in response to variable reward contingencies and outcomes in cocaine addicts.

    Science.gov (United States)

    Morie, Kristen P; De Sanctis, Pierfilippo; Garavan, Hugh; Foxe, John J

    2016-03-01

    We investigated anticipatory and consummatory reward processing in cocaine addiction. In addition, we set out to assess whether task-monitoring systems were appropriately recalibrated in light of variable reward schedules. We also examined neural measures of task-monitoring and reward processing as a function of hedonic tone, since anhedonia is a vulnerability marker for addiction that is obviously germane in the context of reward processing. High-density event-related potentials were recorded while participants performed a speeded response task that systematically varied anticipated probabilities of reward receipt. The paradigm dissociated feedback regarding task success (or failure) from feedback regarding the value of reward (or loss), so that task-monitoring and reward processing could be examined in partial isolation. Twenty-three active cocaine abusers and 23 age-matched healthy controls participated. Cocaine abusers showed amplified anticipatory responses to reward predictive cues, but crucially, these responses were not as strongly modulated by reward probability as in controls. Cocaine users also showed blunted responses to feedback about task success or failure and did not use this information to update predictions about reward. In turn, they showed clearly blunted responses to reward feedback. In controls and users, measures of anhedonia were associated with reward motivation. In cocaine users, anhedonia was also associated with diminished monitoring and reward feedback responses. Findings imply that reward anticipation and monitoring deficiencies in addiction are associated with increased responsiveness to reward cues but impaired ability to predict reward in light of task contingencies, compounded by deficits in responding to actual reward outcomes.

  3. Outcomes in registered, ongoing randomized controlled trials of patient education.

    Directory of Open Access Journals (Sweden)

    Cécile Pino

    Full Text Available BACKGROUND: With the increasing prevalence of chronic noncommunicable diseases, patient education is becoming important to strengthen disease prevention and control. We aimed to systematically determine the extent to which registered, ongoing randomized controlled trials (RCTs evaluated an educational intervention focus on patient-important outcomes (i.e., outcomes measuring patient health status and quality of life. METHODS: On May 6, 2009, we searched for all ongoing RCTs registered in the World Health Organization International Clinical Trials Registry platform. We used a standardized data extraction form to collect data and determined whether the outcomes assessed were 1 patient-important outcomes such as clinical events, functional status, pain, or quality of life or 2 surrogate outcomes, such as biological outcome, treatment adherence, or patient knowledge. PRINCIPAL FINDINGS: We selected 268 of the 642 potentially eligible studies and assessed a random sample of 150. Patient-important outcomes represented 54% (178 of 333 of all primary outcomes and 46% (286 of 623 of all secondary outcomes. Overall, 69% of trials (104 of 150 used at least one patient-important outcome as a primary outcome and 66% (99 of 150 as a secondary outcome. Finally, for 31% of trials (46 of 150, primary outcomes were only surrogate outcomes. The results varied by medical area. In neuropsychiatric disorders, patient important outcomes represented 84% (51 of 61 of primary outcomes, as compared with 54% (32 of 59 in malignant neoplasm and 18% (4 of 22 in diabetes mellitus trials. In addition, only 35% assessed the long-term impact of interventions (i.e., >6 months. CONCLUSIONS: There is a need to improve the relevance of outcomes and to assess the long term impact of educational interventions in RCTs.

  4. Sensitivity of adaptive enrichment trial designs to accrual rates, time to outcome measurement, and prognostic variables

    Directory of Open Access Journals (Sweden)

    Tianchen Qian

    2017-12-01

    Full Text Available Adaptive enrichment designs involve rules for restricting enrollment to a subset of the population during the course of an ongoing trial. This can be used to target those who benefit from the experimental treatment. Trial characteristics such as the accrual rate and the prognostic value of baseline variables are typically unknown when a trial is being planned; these values are typically assumed based on information available before the trial starts. Because of the added complexity in adaptive enrichment designs compared to standard designs, it may be of special concern how sensitive the trial performance is to deviations from assumptions. Through simulation studies, we evaluate the sensitivity of Type I error, power, expected sample size, and trial duration to different design characteristics. Our simulation distributions mimic features of data from the Alzheimer's Disease Neuroimaging Initiative cohort study, and involve two subpopulations based on a genetic marker. We investigate the impact of the following design characteristics: the accrual rate, the time from enrollment to measurement of a short-term outcome and the primary outcome, and the prognostic value of baseline variables and short-term outcomes. To leverage prognostic information in baseline variables and short-term outcomes, we use a semiparametric, locally efficient estimator, and investigate its strengths and limitations compared to standard estimators. We apply information-based monitoring, and evaluate how accurately information can be estimated in an ongoing trial.

  5. Internal Interdecadal Variability in CMIP5 Control Simulations

    Science.gov (United States)

    Cheung, A. H.; Mann, M. E.; Frankcombe, L. M.; England, M. H.; Steinman, B. A.; Miller, S. K.

    2015-12-01

    Here we make use of control simulations from the CMIP5 models to quantify the amplitude of the interdecadal internal variability component in Atlantic, Pacific, and Northern Hemisphere mean surface temperature. We compare against estimates derived from observations using a semi-empirical approach wherein the forced component as estimated using CMIP5 historical simulations is removed to yield an estimate of the residual, internal variability. While the observational estimates are largely consistent with those derived from the control simulations for both basins and the Northern Hemisphere, they lie in the upper range of the model distributions, suggesting the possibility of differences between the amplitudes of observed and modeled variability. We comment on some possible reasons for the disparity.

  6. A variable structure tracking controller for robot manipulators

    International Nuclear Information System (INIS)

    Lee, Jung Hoon; Shin, Hwi Beom

    1997-01-01

    In this paper, a continuous variable structure tracking controller is designed for the purpose of the control of robot manipulators to follow a given desired planned trajectory with high accuracy. The robustness and continuity of the algorithm are much improved by means of the feedforward compensation technique based on the disturbance observer without any chattering problem. Also the stability of the algorithm is analyzed in detail, further more the usefulness and good performances are verified through computer simulation studies. (author)

  7. Preschool Children's Control of Action Outcomes

    Science.gov (United States)

    Freier, Livia; Cooper, Richard P.; Mareschal, Denis

    2017-01-01

    Naturalistic goal-directed behaviours require the engagement and maintenance of appropriate levels of cognitive control over relatively extended intervals of time. In two experiments, we examined preschool children's abilities to maintain top-down control throughout the course of a sequential task. Both 3- and 5-year-olds demonstrated good…

  8. Gait variability and motor control in people with knee osteoarthritis

    DEFF Research Database (Denmark)

    Alkjaer, Tine; Raffalt, Peter C; Dalsgaard, Helle

    2015-01-01

    fluctuation analysis. The motor control was assessed by the soleus (SO) Hoffmann (H)-reflex modulation and muscle co-activation during walking. The results showed no statistically significant mean group differences in any of the gait variability measures or muscle co-activation levels. The SO H...

  9. A current controlled variable delay superconducting transmission line

    International Nuclear Information System (INIS)

    Anlage, S.M.; Snortland, H.J.; Beasley, M.R.

    1989-01-01

    The authors present a device concept for a current-controlled variable delay for superconducting transmission line. The device makes use of the change in kinetic inductance of a superconducting transmission line under the application of a DC bias current. The relevant materials parameters and several promising superconducting materials have been identified

  10. LQG Controller Design for Pitch Regulated Variable Speed Wind Turbine

    DEFF Research Database (Denmark)

    Imran, Raja Muhammed; Hussain, Dil Muhammad Akbar; Chen, Zhe

    2014-01-01

    Variable speed wind turbine is a complex and nonlinear system, a sophisticated control is required to meet the challenges posed by these systems. This paper is presenting a pitch regulation strategy based on LQG (Linear Quadratic Gaussian) to regulate turbine at its rated power and to reject...

  11. Analysis on electronic control unit of continuously variable transmission

    Science.gov (United States)

    Cao, Shuanggui

    Continuously variable transmission system can ensure that the engine work along the line of best fuel economy, improve fuel economy, save fuel and reduce harmful gas emissions. At the same time, continuously variable transmission allows the vehicle speed is more smooth and improves the ride comfort. Although the CVT technology has made great development, but there are many shortcomings in the CVT. The CVT system of ordinary vehicles now is still low efficiency, poor starting performance, low transmission power, and is not ideal controlling, high cost and other issues. Therefore, many scholars began to study some new type of continuously variable transmission. The transmission system with electronic systems control can achieve automatic control of power transmission, give full play to the characteristics of the engine to achieve optimal control of powertrain, so the vehicle is always traveling around the best condition. Electronic control unit is composed of the core processor, input and output circuit module and other auxiliary circuit module. Input module collects and process many signals sent by sensor and , such as throttle angle, brake signals, engine speed signal, speed signal of input and output shaft of transmission, manual shift signals, mode selection signals, gear position signal and the speed ratio signal, so as to provide its corresponding processing for the controller core.

  12. Gait variability and motor control in people with knee osteoarthritis.

    Science.gov (United States)

    Alkjaer, Tine; Raffalt, Peter C; Dalsgaard, Helle; Simonsen, Erik B; Petersen, Nicolas C; Bliddal, Henning; Henriksen, Marius

    2015-10-01

    Knee osteoarthritis (OA) is a common disease that impairs walking ability and function. We compared the temporal gait variability and motor control in people with knee OA with healthy controls. The purpose was to test the hypothesis that the temporal gait variability would reflect a more stereotypic pattern in people with knee OA compared with healthy age-matched subjects. To assess the gait variability the temporal structure of the ankle and knee joint kinematics was quantified by the largest Lyapunov exponent and the stride time fluctuations were quantified by sample entropy and detrended fluctuation analysis. The motor control was assessed by the soleus (SO) Hoffmann (H)-reflex modulation and muscle co-activation during walking. The results showed no statistically significant mean group differences in any of the gait variability measures or muscle co-activation levels. The SO H-reflex amplitude was significantly higher in the knee OA group around heel strike when compared with the controls. The mean group difference in the H-reflex in the initial part of the stance phase (control-knee OA) was -6.6% Mmax (95% CI: -10.4 to -2.7, p=0.041). The present OA group reported relatively small impact of their disease. These results suggest that the OA group in general sustained a normal gait pattern with natural variability but with suggestions of facilitated SO H-reflex in the swing to stance phase transition. We speculate that the difference in SO H-reflex modulation reflects that the OA group increased the excitability of the soleus stretch reflex as a preparatory mechanism to avoid sudden collapse of the knee joint which is not uncommon in knee OA. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Control Method for Variable Speed Wind Turbines to Support Temporary Primary Frequency Control

    DEFF Research Database (Denmark)

    Wang, Haijiao; Chen, Zhe; Jiang, Quanyuan

    2014-01-01

    This paper develops a control method for variable speed wind turbines (VSWTs) to support temporary primary frequency control of power system. The control method contains two parts: (1) up-regulate support control when a frequency drop event occurs; (2) down-regulate support control when a frequen...

  14. Variable structure control of complex systems analysis and design

    CERN Document Server

    Yan, Xing-Gang; Edwards, Christopher

    2017-01-01

    This book systematizes recent research work on variable-structure control. It is self-contained, presenting necessary mathematical preliminaries so that the theoretical developments can be easily understood by a broad readership. The text begins with an introduction to the fundamental ideas of variable-structure control pertinent to their application in complex nonlinear systems. In the core of the book, the authors lay out an approach, suitable for a large class of systems, that deals with system uncertainties with nonlinear bounds. Its treatment of complex systems in which limited measurement information is available makes the results developed convenient to implement. Various case-study applications are described, from aerospace, through power systems to river pollution control with supporting simulations to aid the transition from mathematical theory to engineering practicalities. The book addresses systems with nonlinearities, time delays and interconnections and considers issues such as stabilization, o...

  15. Considering Variable Road Geometry in Adaptive Vehicle Speed Control

    Directory of Open Access Journals (Sweden)

    Xinping Yan

    2013-01-01

    Full Text Available Adaptive vehicle speed control is critical for developing Advanced Driver Assistance Systems (ADAS. Vehicle speed control considering variable road geometry has become a hotspot in ADAS research. In this paper, first, an exploration of intrinsic relationship between vehicle operation and road geometry is made. Secondly, a collaborative vehicle coupling model, a road geometry model, and an AVSC, which can respond to variable road geometry in advance, are developed. Then, based on H∞ control method and the minimum energy principle, a performance index is specified by a cost function for the proposed AVSC, which can explicitly consider variable road geometry in its optimization process. The proposed AVSC is designed by the Hamilton-Jacobi Inequality (HJI. Finally, simulations are carried out by combining the vehicle model with the road geometry model, in an aim of minimizing the performance index of the AVSC. Analyses of the simulation results indicate that the proposed AVSC can automatically and effectively regulate speed according to variable road geometry. It is believed that the proposed AVSC can be used to improve the economy, comfort, and safety effects of current ADAS.

  16. Discrete factor approximations in simultaneous equation models: estimating the impact of a dummy endogenous variable on a continuous outcome.

    Science.gov (United States)

    Mroz, T A

    1999-10-01

    This paper contains a Monte Carlo evaluation of estimators used to control for endogeneity of dummy explanatory variables in continuous outcome regression models. When the true model has bivariate normal disturbances, estimators using discrete factor approximations compare favorably to efficient estimators in terms of precision and bias; these approximation estimators dominate all the other estimators examined when the disturbances are non-normal. The experiments also indicate that one should liberally add points of support to the discrete factor distribution. The paper concludes with an application of the discrete factor approximation to the estimation of the impact of marriage on wages.

  17. What Variables are Associated with Successful Weight Loss Outcomes for Bariatric Surgery After One Year?

    Science.gov (United States)

    Robinson, Athena H.; Adler, Sarah; Stevens, Helen B.; Darcy, Alison M.; Morton, John M.; Safer, Debra L.

    2014-01-01

    Background Prior evidence indicates that predictors of weight loss outcomes after gastric bypass surgery fall within 5 domains: 1) presurgical factors; 2) postsurgical psychosocial variables (e.g., support group attendance); 3) postsurgical eating patterns; 4) postsurgical physical activity; and 5) follow-up at postsurgical clinic. However, little data exist on which specific behavioral predictors are most associated with successful outcomes (e.g., ≥50% excess weight loss) when considering the 5 domains simultaneously. Objectives Specify the behavioral variables, and their respective cutoff points, most associated with successful weight loss outcomes. Setting On-line survey. Methods Signal Detection Analysis evaluated associations between 84 pre-and postsurgical behavioral variables (within the 5 domains) and successful weight loss at ≥1 year in 274 post-gastric bypass surgery patients. Results Successful weight loss was highest (92.6%) among those reporting dietary adherence of >3 on a 9 point scale (median=5) who grazed no more than once-per-day. Among participants reporting dietary adherence <3 and grazing daily or less, success rates more than doubled when highest lifetime Body Mass Index was <53.7 kg/m2. Success rates also doubled for participants with dietary adherence =3 if attending support groups. No variables from the physical activity or postsurgical follow-up domains were significant, nor were years since surgery. The overall model’s sensitivity =.62, specificity =.92. Conclusions To our knowledge, this is the first study to simultaneously consider the relative contribution of behavioral variables within 5 domains and offer clinicians an assessment algorithm identifying cut-off points for behaviors most associated with successful postsurgical weight loss. Such data may inform prospective study designs and postsurgical interventions. PMID:24913590

  18. Economic Statistical Design of Variable Sampling Interval X¯$\\overline X $ Control Chart Based on Surrogate Variable Using Genetic Algorithms

    Directory of Open Access Journals (Sweden)

    Lee Tae-Hoon

    2016-12-01

    Full Text Available In many cases, a X¯$\\overline X $ control chart based on a performance variable is used in industrial fields. Typically, the control chart monitors the measurements of a performance variable itself. However, if the performance variable is too costly or impossible to measure, and a less expensive surrogate variable is available, the process may be more efficiently controlled using surrogate variables. In this paper, we present a model for the economic statistical design of a VSI (Variable Sampling Interval X¯$\\overline X $ control chart using a surrogate variable that is linearly correlated with the performance variable. We derive the total average profit model from an economic viewpoint and apply the model to a Very High Temperature Reactor (VHTR nuclear fuel measurement system and derive the optimal result using genetic algorithms. Compared with the control chart based on a performance variable, the proposed model gives a larger expected net income per unit of time in the long-run if the correlation between the performance variable and the surrogate variable is relatively high. The proposed model was confined to the sample mean control chart under the assumption that a single assignable cause occurs according to the Poisson process. However, the model may also be extended to other types of control charts using a single or multiple assignable cause assumptions such as VSS (Variable Sample Size X¯$\\overline X $ control chart, EWMA, CUSUM charts and so on.

  19. A design method of compensators for multi-variable control system with PID controllers 'CHARLY'

    International Nuclear Information System (INIS)

    Fujiwara, Toshitaka; Yamada, Katsumi

    1985-01-01

    A systematic design method of compensators for a multi-variable control system having usual PID controllers in its loops is presented in this paper. The method itself is able: to determine the main manipulating variable corresponding to each controlled variable with a sensitivity analysis in the frequency domain. to tune PID controllers sufficiently to realize adequate control actions with a searching technique of minimum values of cost functionals. to design compensators improving the control preformance and to simulate a total system for confirming the designed compensators. In the phase of compensator design, the state variable feed-back gain is obtained by means of the OPTIMAL REGULATOR THEORY for the composite system of plant and PID controllers. The transfer function type compensators the configurations of which were previously given are, then, designed to approximate the frequency responces of the above mentioned state feed-back system. An example is illustrated for convenience. (author)

  20. Heart rate variability measured early in patients with evolving acute coronary syndrome and 1-year outcomes of rehospitalization and mortality.

    Science.gov (United States)

    Harris, Patricia R E; Stein, Phyllis K; Fung, Gordon L; Drew, Barbara J

    2014-01-01

    This study sought to examine the prognostic value of heart rate variability (HRV) measurement initiated immediately after emergency department presentation for patients with acute coronary syndrome (ACS). Altered HRV has been associated with adverse outcomes in heart disease, but the value of HRV measured during the earliest phases of ACS related to risk of 1-year rehospitalization and death has not been established. Twenty-four-hour Holter recordings of 279 patients with ACS were initiated within 45 minutes of emergency department arrival; recordings with ≥18 hours of sinus rhythm were selected for HRV analysis (number [N] =193). Time domain, frequency domain, and nonlinear HRV were examined. Survival analysis was performed. During the 1-year follow-up, 94 patients were event-free, 82 were readmitted, and 17 died. HRV was altered in relation to outcomes. Predictors of rehospitalization included increased normalized high frequency power, decreased normalized low frequency power, and decreased low/high frequency ratio. Normalized high frequency >42 ms(2) predicted rehospitalization while controlling for clinical variables (hazard ratio [HR] =2.3; 95% confidence interval [CI] =1.4-3.8, P=0.001). Variables significantly associated with death included natural logs of total power and ultra low frequency power. A model with ultra low frequency power 0.3 ng/mL (HR =4.0; 95% CI =1.3-12.1; P=0.016) revealed that each contributed independently in predicting mortality. Nonlinear HRV variables were significant predictors of both outcomes. HRV measured close to the ACS onset may assist in risk stratification. HRV cut-points may provide additional, incremental prognostic information to established assessment guidelines, and may be worthy of additional study.

  1. Controls on the variability of net infiltration to desert sandstone

    Science.gov (United States)

    Heilweil, Victor M.; McKinney, Tim S.; Zhdanov, Michael S.; Watt, Dennis E.

    2007-01-01

    As populations grow in arid climates and desert bedrock aquifers are increasingly targeted for future development, understanding and quantifying the spatial variability of net infiltration becomes critically important for accurately inventorying water resources and mapping contamination vulnerability. This paper presents a conceptual model of net infiltration to desert sandstone and then develops an empirical equation for its spatial quantification at the watershed scale using linear least squares inversion methods for evaluating controlling parameters (independent variables) based on estimated net infiltration rates (dependent variables). Net infiltration rates used for this regression analysis were calculated from environmental tracers in boreholes and more than 3000 linear meters of vadose zone excavations in an upland basin in southwestern Utah underlain by Navajo sandstone. Soil coarseness, distance to upgradient outcrop, and topographic slope were shown to be the primary physical parameters controlling the spatial variability of net infiltration. Although the method should be transferable to other desert sandstone settings for determining the relative spatial distribution of net infiltration, further study is needed to evaluate the effects of other potential parameters such as slope aspect, outcrop parameters, and climate on absolute net infiltration rates.

  2. Visit-to-visit cholesterol variability correlates with coronary atheroma progression and clinical outcomes.

    Science.gov (United States)

    Clark, Donald; Nicholls, Stephen J; St John, Julie; Elshazly, Mohamed B; Kapadia, Samir R; Tuzcu, E Murat; Nissen, Steven E; Puri, Rishi

    2018-04-21

    Utilizing serial intravascular ultrasonography (IVUS), we aimed to exam the association of intra-individual lipid variability, coronary atheroma progression, and clinical outcomes. We performed a post hoc patient-level analysis of nine clinical trials involving 4976 patients with coronary artery disease who underwent serial coronary IVUS in the setting of a range of medical therapies. We assessed the associations between progression in percent atheroma volume (ΔPAV), clinical outcomes, and visit-to-visit lipid variability including low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), non-HDL-C, total cholesterol (TC)/HDL-C, and apolipoprotein B (ApoB). Variability of lipid parameters was measured using intra-individual standard deviation over 3, 6, 12, 18, and 24 months. Atherogenic lipoprotein variability significantly associated with ΔPAV [odds ratio (95% confidence interval; P-value), LDL-C: 1.09 (1.02, 1.17, P = 0.01); non-HDL-C: 1.10 (1.02, 1.18, P = 0.01); TC/HDL-C: 1.14 (1.06, 1.24, P = 0.001); ApoB: 1.13 (1.03, 1.24, P = 0.01)]. Survival curves revealed significant stepwise relationships between cumulative major adverse cardiovascular events and increasing quartiles of atherogenic lipoprotein variability at 24-months follow-up (log-rank P C). Stronger associations were noted between achieved lipoprotein levels and ΔPAV [LDL-C: 1.27 (1.17, 1.39; P C: 1.32 (1.21, 1.45; P C: 1.31 (1.19, 1.45; P < 0.001); ApoB: 1.20 (1.07, 1.35; P = 0.003)]. Greater visit-to-visit variability in atherogenic lipoprotein levels significantly associates with coronary atheroma progression and clinical outcomes, although the association between achieved atherogenic lipoproteins and atheroma progression appears stronger. These data highlight the importance of achieving low and consistent atherogenic lipoprotein levels to promote plaque regression and improve clinical outcomes.

  3. Optimization of Drilling Resistance Measurement (DRM) user-controlled variables

    OpenAIRE

    Tudor, Dumitrescu; Pesce, Giovanni; Ball, Richard

    2017-01-01

    Drilling Resistance Measurement (DRM) is recognised as an important on-site micro-invasive procedure for assessment of construction materials. This paper presents a detailed investigation of user-controlled variables and their influence on drilling resistance. The study proves that the ratio of penetration rate/rotational speed (PR/RPM) is proportional to drilling resistance. Data from Bath stone and an artificial reference stone demonstrates how different materials can be compared using thei...

  4. Control Multivariable Centralizado con Desacoplo para Aerogeneradores de Velocidad Variable

    Directory of Open Access Journals (Sweden)

    Miguel E. González

    2010-10-01

    Full Text Available Resumen: El diseño de sistemas de control para aerogeneradores de velocidad variable representa un reto importante ya que se trata de procesos multivariables no lineales, con fuertes perturbaciones, diversas restricciones y gran interacción entre sus variables. Bajo este escenario se debe generar eficientemente la potencia eléctrica y al mismo tiempo regular la velocidad de giro de la turbina. En este trabajo se proponen varios esquemas de control multivariable, con el objetivo de mejorar el rendimiento de los aerogeneradores atenuando los efectos de la interacción entre sus variables. La solución propuesta se basa en controladores PID con diseños del tipo descentralizado, centralizado con diversas redes de desacoplo y un esquema con cuatro PI. El comportamiento del aerogenerador se describe mediante un modelo matemático no lineal, que se linealiza para obtener una matriz de funciones de transferencia, a partir de la cual se diseñan los controladores. Finalmente se realiza un análisis comparativo para determinar qué controlador presenta mejores resultados, aplicando perturbaciones con un modelo de la velocidad del viento y cambios aleatorios de la carga eléctrica. Palabras Clave: Aerogenerador, Control Multivariable, Modelado e Interacción

  5. Evaluation of standardized and applied variables in predicting treatment outcomes of polytrauma patients.

    Science.gov (United States)

    Aksamija, Goran; Mulabdic, Adi; Rasic, Ismar; Muhovic, Samir; Gavric, Igor

    2011-01-01

    Polytrauma is defined as an injury where they are affected by at least two different organ systems or body, with at least one life-threatening injuries. Given the multilevel model care of polytrauma patients within KCUS are inevitable weaknesses in the management of this category of patients. To determine the dynamics of existing procedures in treatment of polytrauma patients on admission to KCUS, and based on statistical analysis of variables applied to determine and define the factors that influence the final outcome of treatment, and determine their mutual relationship, which may result in eliminating the flaws in the approach to the problem. The study was based on 263 polytrauma patients. Parametric and non-parametric statistical methods were used. Basic statistics were calculated, based on the calculated parameters for the final achievement of research objectives, multicoleration analysis, image analysis, discriminant analysis and multifactorial analysis were used. From the universe of variables for this study we selected sample of n = 25 variables, of which the first two modular, others belong to the common measurement space (n = 23) and in this paper defined as a system variable methods, procedures and assessments of polytrauma patients. After the multicoleration analysis, since the image analysis gave a reliable measurement results, we started the analysis of eigenvalues, that is defining the factors upon which they obtain information about the system solve the problem of the existing model and its correlation with treatment outcome. The study singled out the essential factors that determine the current organizational model of care, which may affect the treatment and better outcome of polytrauma patients. This analysis has shown the maximum correlative relationships between these practices and contributed to development guidelines that are defined by isolated factors.

  6. Digitally controlled oscillator design with a variable capacitance XOR gate

    International Nuclear Information System (INIS)

    Kumar, Manoj; Arya, Sandeep K.; Pandey, Sujata

    2011-01-01

    A digitally controlled oscillator (DCO) using a three-transistor XOR gate as the variable load has been presented. A delay cell using an inverter and a three-transistor XOR gate as the variable capacitance is also proposed. Three-, five- and seven-stage DCO circuits have been designed using the proposed delay cell. The output frequency is controlled digitally with bits applied to the delay cells. The three-bit DCO shows output frequency and power consumption variation in the range of 3.2486–4.0267 GHz and 0.6121–0.3901 mW, respectively, with a change in the control word 111–000. The five-bit DCO achieves frequency and power of 1.8553–2.3506 GHz and 1.0202–0.6501 mW, respectively, with a change in the control word 11111–00000. Moreover, the seven-bit DCO shows a frequency and power consumption variation of 1.3239–1.6817 GHz and 1.4282–0.9102 mW, respectively, with a varying control word 1111111–0000000. The power consumption and output frequency of the proposed circuits have been compared with earlier reported circuits and the present approaches show significant improvements. (semiconductor integrated circuits)

  7. Real-time laser cladding control with variable spot size

    Science.gov (United States)

    Arias, J. L.; Montealegre, M. A.; Vidal, F.; Rodríguez, J.; Mann, S.; Abels, P.; Motmans, F.

    2014-03-01

    Laser cladding processing has been used in different industries to improve the surface properties or to reconstruct damaged pieces. In order to cover areas considerably larger than the diameter of the laser beam, successive partially overlapping tracks are deposited. With no control over the process variables this conduces to an increase of the temperature, which could decrease mechanical properties of the laser cladded material. Commonly, the process is monitored and controlled by a PC using cameras, but this control suffers from a lack of speed caused by the image processing step. The aim of this work is to design and develop a FPGA-based laser cladding control system. This system is intended to modify the laser beam power according to the melt pool width, which is measured using a CMOS camera. All the control and monitoring tasks are carried out by a FPGA, taking advantage of its abundance of resources and speed of operation. The robustness of the image processing algorithm is assessed, as well as the control system performance. Laser power is decreased as substrate temperature increases, thus maintaining a constant clad width. This FPGA-based control system is integrated in an adaptive laser cladding system, which also includes an adaptive optical system that will control the laser focus distance on the fly. The whole system will constitute an efficient instrument for part repair with complex geometries and coating selective surfaces. This will be a significant step forward into the total industrial implementation of an automated industrial laser cladding process.

  8. Heart rate variability measured early in patients with evolving acute coronary syndrome and 1-year outcomes of rehospitalization and mortality

    Directory of Open Access Journals (Sweden)

    Harris PR

    2014-08-01

    Full Text Available Patricia R E Harris,1 Phyllis K Stein,2 Gordon L Fung,3 Barbara J Drew4 1Electrocardiographic Monitoring Research Laboratory, School of Nursing, Department of Physiological Nursing, University of California, San Francisco, CA, USA; 2Heart Rate Variability Laboratory, School of Medicine, Division of Cardiology, Washington University, St Louis, MO, USA; 3Cardiology Services, Mount Zion, Department of Medicine, Division of Cardiology, University of California, San Francisco, CA, USA; 4School of Nursing, Department of Physiological Nursing, Division of Cardiology, University of California, San Francisco, CA, USA Objective: This study sought to examine the prognostic value of heart rate variability (HRV measurement initiated immediately after emergency department presentation for patients with acute coronary syndrome (ACS. Background: Altered HRV has been associated with adverse outcomes in heart disease, but the value of HRV measured during the earliest phases of ACS related to risk of 1-year rehospitalization and death has not been established. Methods: Twenty-four-hour Holter recordings of 279 patients with ACS were initiated within 45 minutes of emergency department arrival; recordings with ≥18 hours of sinus rhythm were selected for HRV analysis (number [N] =193. Time domain, frequency domain, and nonlinear HRV were examined. Survival analysis was performed. Results: During the 1-year follow-up, 94 patients were event-free, 82 were readmitted, and 17 died. HRV was altered in relation to outcomes. Predictors of rehospitalization included increased normalized high frequency power, decreased normalized low frequency power, and decreased low/high frequency ratio. Normalized high frequency >42 ms2 predicted rehospitalization while controlling for clinical variables (hazard ratio [HR] =2.3; 95% confidence interval [CI] =1.4–3.8, P=0.001. Variables significantly associated with death included natural logs of total power and ultra low frequency

  9. Glucose control and cardiovascular outcomes: Reorienting approach

    Directory of Open Access Journals (Sweden)

    Romesh eKhardori

    2012-08-01

    Full Text Available Cardiovascular disease accounts for nearly 70 % of morbidity and mortality in patients with diabetes mellitus. Strides made in diabetes care have indeed helped prevent or reduce the burden of microvascular complications in both type-1 and type-2 diabetes. However, the same can’t be said about macrovascular disease in diabetes. Several prospective trials so far have failed to provide conclusive evidence of glycemic control superiority in reducing macrovascular complications or death rate in people with advanced disease or those with long duration of diabetes. There are trends that suggest that benefits are restricted to those with lesser burden and shorter duration of disease. Furthermore, it is also suggested that benefits might accrue but it would take longer time to manifest. Clinicians are fraught with challenge to decide how to triage patients for intensified care versus less intense care. This review focusses on evidence and attempts to provide a balanced view of literature that has radically affected how physicians treat patients with macrovascular disease. It also takes cognizance of the fact that natural course of disease may be changing as well possibly related to better overall awareness and possibly improved access to information about better individual healthcare. The review further takes note of some hard held notions about pathobiology of disease that must be interpreted with caution in light of new emerging data. In light of recent developments ADA and EASD have taken step to provide some guidance to clinicians through a joint position statement. A lot more research would be required to figure out how best to manage macrovascular disease in diabetes mellitus. Glucocentric stance would have to yield to evidence based, and possibly, concurrent multifactorial intervention to enhance quality of care that is safe and effective.

  10. Closed-loop control of grasping with a myoelectric hand prosthesis: which are the relevant feedback variables for force control?

    Science.gov (United States)

    Ninu, Andrei; Dosen, Strahinja; Muceli, Silvia; Rattay, Frank; Dietl, Hans; Farina, Dario

    2014-09-01

    In closed-loop control of grasping by hand prostheses, the feedback information sent to the user is usually the actual controlled variable, i.e., the grasp force. Although this choice is intuitive and logical, the force production is only the last step in the process of grasping. Therefore, this study evaluated the performance in controlling grasp strength using a hand prosthesis operated through a complete grasping sequence while varying the feedback variables (e.g., closing velocity, grasping force), which were provided to the user visually or through vibrotactile stimulation. The experiments were conducted on 13 volunteers who controlled the Otto Bock Sensor Hand Speed prosthesis. Results showed that vibrotactile patterns were able to replace the visual feedback. Interestingly, the experiments demonstrated that direct force feedback was not essential for the control of grasping force. The subjects were indeed able to control the grip strength, predictively, by estimating the grasping force from the prosthesis velocity of closing. Therefore, grasping without explicit force feedback is not completely blind, contrary to what is usually assumed. In our study we analyzed grasping with a specific prosthetic device, but the outcomes are also applicable for other devices, with one or more degrees-of-freedom. The necessary condition is that the electromyography (EMG) signal directly and proportionally controls the velocity/grasp force of the hand, which is a common approach among EMG controlled prosthetic devices. The results provide important indications on the design of closed-loop EMG controlled prosthetic systems.

  11. Investigation of torque control using a variable slip induction generator

    Energy Technology Data Exchange (ETDEWEB)

    Bossanyi, E A; Gamble, C R

    1991-07-01

    An investigation of the possibilities of using a variable slip induction generator to control wind turbine transmission torque has been carried out. Such a generator consists of a wound rotor induction generator with its rotor winding connected to an external variable resistance circuit. By controlling the external resistance, the torque-slip characteristic of the generator can be modified, allowing efficient, low-slip operation below rated wind speed and compliant, high-slip operation above rated, where the additional losses are of no consequence but the resulting compliance allows a much reduced duty to be specified for the transmission and gearbox. A number of hardware options have been investigated for the variable resistance rotor circuit, the main options being either a rectifier and DC chopper or an AC regulator. Both of these options use semiconductor switching devices, for which the relative merits of thyristors, MOSFETs, GTOs and transistors have been investigated. A favoured scheme consisting of an AC regulator using GTOs has been provisionally selected. This choice uses some non-standard equipment but is expected to give negligible problems with harmonics. A comprehensive simulation model has been set up and used to investigate the behaviour of the whole system. (author).

  12. Complexity Variability Assessment of Nonlinear Time-Varying Cardiovascular Control

    Science.gov (United States)

    Valenza, Gaetano; Citi, Luca; Garcia, Ronald G.; Taylor, Jessica Noggle; Toschi, Nicola; Barbieri, Riccardo

    2017-02-01

    The application of complex systems theory to physiology and medicine has provided meaningful information about the nonlinear aspects underlying the dynamics of a wide range of biological processes and their disease-related aberrations. However, no studies have investigated whether meaningful information can be extracted by quantifying second-order moments of time-varying cardiovascular complexity. To this extent, we introduce a novel mathematical framework termed complexity variability, in which the variance of instantaneous Lyapunov spectra estimated over time serves as a reference quantifier. We apply the proposed methodology to four exemplary studies involving disorders which stem from cardiology, neurology and psychiatry: Congestive Heart Failure (CHF), Major Depression Disorder (MDD), Parkinson’s Disease (PD), and Post-Traumatic Stress Disorder (PTSD) patients with insomnia under a yoga training regime. We show that complexity assessments derived from simple time-averaging are not able to discern pathology-related changes in autonomic control, and we demonstrate that between-group differences in measures of complexity variability are consistent across pathologies. Pathological states such as CHF, MDD, and PD are associated with an increased complexity variability when compared to healthy controls, whereas wellbeing derived from yoga in PTSD is associated with lower time-variance of complexity.

  13. Power system integration and control of variable speed wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Eek, Jarle

    2009-12-15

    A wind power plant is a highly dynamic system that dependent on the type of technology requires a number of automatic control loops. This research deals with modelling, control and analysis related to power system integration of variable speed, pitch controlled wind turbines. All turbine components have been modelled and implemented in the power system simulation program SIMPOW, and a description of the modelling approach for each component is given. The level of model detail relates to the classical modelling of power system components for power system stability studies, where low frequency oscillations are of special importance. The wind turbine model includes a simplified representation of the developed rotor torque and the thrust force based on C{sub p-} and C{sub t} characteristic curves. The mechanical system model represents the fundamental torsional mode and the first mode of blades and tower movements. Two generator technologies have been investigated. The doubly fed induction generator (DFIG) and the stator converter interfaced permanent magnet synchronous generator (PMSG). A simplified model of a 2 level voltage source converter is used for both machine types. The generator converter controllers have been given special attention. All model components are linearized for the purpose of control system design and power system interaction related to small signal stability analysis. Different control strategies discussed in the literature have been investigated with regard to power system interaction aspects. All control parameters are identified using the internal model control approach. The analysis is focused on three main areas: 1. Identification of low damped oscillatory modes. This is carried out by the establishment and discussion of wind turbine modelling. 2. Interaction between control loops. A systematic approach is presented in order to analyse the influence of control loops used in variable speed wind turbines. 3.Impact on power system performance

  14. Long-term outcome of major depressive disorder in psychiatric patients is variable.

    Science.gov (United States)

    Holma, K Mikael; Holma, Irina A K; Melartin, Tarja K; Rytsälä, Heikki J; Isometsä, Erkki T

    2008-02-01

    The prevailing view of outcome of major depressive disorder (MDD), based on mostly inpatient cohorts sampled from tertiary centers, emphasizes chronicity and frequent recurrences. We investigated the long-term outcome of a regionally representative psychiatric MDD cohort comprising mainly outpatients. The Vantaa Depression Study included 163 patients with DSM-IV MDD (71.5% of those eligible) diagnosed using structured and semistructured interviews and followed up at 6 months, 18 months, and 5 years with a life chart between February 1, 1997, and April 30, 2004. The effects of comorbid disorders and other predictors on outcome were comprehensively investigated. Over the 5-year follow-up, 98.8% of patients achieved a symptom state below major depressive episode (MDE) criteria, and 88.4% reached full remission, with the median time to full remission being 11.0 months. Nearly one third (29.3%) had no recurrences, whereas 30.0% experienced 1, 12.9% experienced 2, and 27.9% experienced 3 or more recurrences. Preceding dysthymic disorder (p = .028), cluster C personality disorder (p = .041), and longer MDE duration prior to entry (p = .011) were the most significant predictors of longer time in achieving full remission. Severity of MDD and comorbidity, especially social phobia, predicted probability of, shorter time to, and number of recurrences. Previous literature on mostly inpatient MDD may have, by generalizing from patients with the most severe psychopathology, overemphasized chronicity of MDD. The long-term outcome of MDD in psychiatric care is variable, with about one tenth of patients having poor, one third having intermediate, and one half having favorable outcomes. In addition to known predictors, cluster C personality disorders and social phobia warrant further attention as predictors of MDD outcome among outpatients.

  15. Power Control in Wireless Sensor Networks with Variable Interference

    Directory of Open Access Journals (Sweden)

    Michele Chincoli

    2016-01-01

    Full Text Available Adaptive transmission power control schemes have been introduced in wireless sensor networks to adjust energy consumption under different network conditions. This is a crucial goal, given the constraints under which sensor communications operate. Power reduction may however have counterproductive effects to network performance. Yet, indiscriminate power boosting may detrimentally affect interference. We are interested in understanding the conditions under which coordinated power reduction may lead to better spectrum efficiency and interference mitigation and, thus, have beneficial effects on network performance. Through simulations, we analyze the performance of sensor nodes in an environment with variable interference. Then we study the relation between transmission power and communication efficiency, particularly in the context of Adaptive and Robust Topology (ART control, showing how appropriate power reduction can benefit both energy and spectrum efficiency. We also identify critical limitations in ART, discussing the potential of more cooperative power control approaches.

  16. Perceived match or mismatch on the Gottman conflict styles: associations with relationship outcome variables.

    Science.gov (United States)

    Busby, Dean M; Holman, Thomas B

    2009-12-01

    Gottman has proposed that there are 3 functional styles of conflict management in couple relationships, labeled Avoidant, Validating, and Volatile, and 1 dysfunctional style, labeled Hostile. Using a sample of 1,983 couples in a committed relationship, we test the association of perceived matches or mismatches on these conflict styles with relationship outcome variables. The results indicate that 32% of the participants perceive there is a mismatch with their conflict style and that of their partner. The Volatile-Avoidant mismatch was particularly problematic and was associated with more stonewalling, relationship problems, and lower levels of relationship satisfaction and stability than the Validating matched style and than other mismatched styles. The most problematic style was the Hostile style. Contrary to existing assumptions by Gottman, the 3 matched functional styles were not equivalent, as the Validating Style was associated with substantially better results on relationship outcome measures than the Volatile and Avoidant styles.

  17. Variable current speed controller for eddy current motors

    Science.gov (United States)

    Gerth, H.L.; Bailey, J.M.; Casstevens, J.M.; Dixon, J.H.; Griffith, B.O.; Igou, R.E.

    1982-03-12

    A speed control system for eddy current motors is provided in which the current to the motor from a constant frequency power source is varied by comparing the actual motor speed signal with a setpoint speed signal to control the motor speed according to the selected setpoint speed. A three-phase variable voltage autotransformer is provided for controlling the voltage from a three-phase power supply. A corresponding plurality of current control resistors is provided in series with each phase of the autotransformer output connected to inputs of a three-phase motor. Each resistor is connected in parallel with a set of normally closed contacts of plurality of relays which are operated by control logic. A logic circuit compares the selected speed with the actual motor speed obtained from a digital tachometer monitoring the motor spindle speed and operated the relays to add or substract resistance equally in each phase of the motor input to vary the motor current to control the motor at the selected speed.

  18. Pregnancy outcome in hyperthyroidism: a case control study.

    Science.gov (United States)

    Aggarawal, Neelam; Suri, Vanita; Singla, Rimpi; Chopra, Seema; Sikka, Pooja; Shah, Viral N; Bhansali, Anil

    2014-01-01

    Data comparing pregnancy outcome in hyperthyroid women with euthyroid women are scarce. Hence, this study was carried out to assess the maternal and fetal outcome in pregnant women with hyperthyroidism to ascertain the effect of disease on pregnancy. This retrospective study was conducted over a period of 28 years. We compared the maternal and fetal outcomes of 208 hyperthyroid women with 403 healthy controls, between women with well-controlled and uncontrolled disease and amongst women diagnosed with hyperthyroidism before and during pregnancy. Maternal outcome: women with hyperthyroidism were at increased risk for preeclampsia (OR = 3.94), intrauterine growth restriction (OR = 2.16), spontaneous preterm labor (OR = 1.73), preterm birth (OR = 1.7), gestational diabetes mellitus (OR = 1.8), and cesarean delivery (OR = 1.47). Hyperthyroid women required induction of labor more frequently (OR = 3.61). Fetal outcome: newborns of hyperthyroid mothers had lower birth weight than normal ones (p = 0.0001). Women with uncontrolled disease had higher odds for still birth (OR = 8.42; 95% CI: 2.01-35.2) and lower birth weight (p = 0.0001). Obstetrical complications were higher in women with hyperthyroidism than normal women. Outcome was worsened by uncontrolled disease. Women with pregestational hyperthyroidism had better outcomes than those diagnosed with it during pregnancy. © 2014 S. Karger AG, Basel.

  19. Torque Modeling and Control of a Variable Compression Engine

    OpenAIRE

    Bergström, Andreas

    2003-01-01

    The SAAB variable compression engine is a new engine concept that enables the fuel consumption to be radically cut by varying the compression ratio. A challenge with this new engine concept is that the compression ratio has a direct influence on the output torque, which means that a change in compression ratio also leads to a change in the torque. A torque change may be felt as a jerk in the movement of the car, and this is an undesirable effect since the driver has no control over the compre...

  20. A Two Year Longitudinal Outcome Study of Addicted Health Care Professionals: An Investigation of the Role of Personality Variables

    Directory of Open Access Journals (Sweden)

    Daniel Angres

    2013-01-01

    Full Text Available The co-morbidity of personality disorders (PDs and other dysregulatory personality patterns with addiction have been well-established, although few studies have examined this interplay on long-term sobriety outcome. In addition, health care professionals suffering from addiction have both a significant public health impact and a unique set of treatment and recovery challenges. The aim of this study was to investigate if personality variables differentiated sobriety outcome in this population over a two year interval. A clinical sample of health care professionals participated in a substance abuse hospital treatment program individually tailored with respect to personality. Participants took the Temperament and Character Inventory and the Millon Clinical Multiaxial Inventory at intake, and were tracked two years post-discharge to determine sobriety status. Univariate analyses showed antisocial personality, female gender, and alcohol dependence were independent predictors of relapse, however a significant relationship between personality and substance use did not exist in multivariate analysis when controlling for demographic variables The lack of multivariate relationships demonstrates the heterogeneity in self-report measures of personality, which suggests the interplay of personality and addiction is complex and individualized.

  1. Meta-modeling of occupancy variables and analysis of their impact on energy outcomes of office buildings

    International Nuclear Information System (INIS)

    Wang, Qinpeng; Augenbroe, Godfried; Kim, Ji-Hyun; Gu, Li

    2016-01-01

    Highlights: • A meta-analysis framework for a stochastic characterization of occupancy variables. • Sensitivity ranking of occupancy variability against all other sources of uncertainty. • Sensitivity of occupant presence for building energy consumption is low. • Accurate mean knowledge is sufficient for predicting building energy consumption. • Prediction of peak demand behavior requires stochastic occupancy modeling. - Abstract: Occupants interact with buildings in various ways via their presence (passive effects) and control actions (active effects). Therefore, understanding the influence of occupants is essential if we are to evaluate the performance of a building. In this paper, we model the mean profiles and variability of occupancy variables (presence and actions) separately. We will use a multi-variate Gaussian distribution to generate mean profiles of occupancy variables, while the variability will be represented by a multi-dimensional time series model, within a framework for a meta-analysis that synthesizes occupancy data gathered from a pool of buildings. We then discuss variants of occupancy models with respect to various outcomes of interest such as HVAC energy consumption and peak demand behavior via a sensitivity analysis. Results show that our approach is able to generate stochastic occupancy profiles, requiring minimum additional input from the energy modeler other than standard diversity profiles. Along with the meta-analysis, we enable the generalization of previous research results and statistical inferences to choose occupancy variables for future buildings. The sensitivity analysis shows that for aggregated building energy consumption, occupant presence has a smaller impact compared to lighting and appliance usage. Specifically, being accumulatively 55% wrong with regard to presence, only translates to 2% error in aggregated cooling energy in July and 3.6% error in heating energy in January. Such a finding redirects focus to the

  2. PROCESS VARIABILITY REDUCTION THROUGH STATISTICAL PROCESS CONTROL FOR QUALITY IMPROVEMENT

    Directory of Open Access Journals (Sweden)

    B.P. Mahesh

    2010-09-01

    Full Text Available Quality has become one of the most important customer decision factors in the selection among the competing product and services. Consequently, understanding and improving quality is a key factor leading to business success, growth and an enhanced competitive position. Hence quality improvement program should be an integral part of the overall business strategy. According to TQM, the effective way to improve the Quality of the product or service is to improve the process used to build the product. Hence, TQM focuses on process, rather than results as the results are driven by the processes. Many techniques are available for quality improvement. Statistical Process Control (SPC is one such TQM technique which is widely accepted for analyzing quality problems and improving the performance of the production process. This article illustrates the step by step procedure adopted at a soap manufacturing company to improve the Quality by reducing process variability using Statistical Process Control.

  3. Diastolic blood pressure variability in 24 hour-ABPM and outcomes of chronic kidney disease
.

    Science.gov (United States)

    Sahutoglu, Tuncay; Sakaci, Tamer

    2018-04-10

    Blood pressure variability (BPV) has been associated with increased morbidity and mortality. There are a few studies that reported worse outcomes of chronic kidney disease (CKD) with greater visit-to-visit BPV (VVV), but data with ambulatory blood pressure monitoring (ABPM) is scarce. Ambulatory hypertensive CKD (stage 2 - 4) patients (> 18 years old) with complete 24 hours of ABPM study (SpaceLabs), who were followed up between January 2012 and December 2016, were retrospectively analyzed for the baseline characteristics and outcomes of CKD. Coefficient of variation (CV) in diastolic blood pressure (DBP) was used as an index of BPV. Data of 191 patients (mean age 59.7 ± 12.4 years, 54.9% males, 42.1% diabetic, mean eGFR-EPI (Chronic Kidney Disease Epidemiology Collaboration) 51.7 ± 22.0 mL/min/1.73m2, mean follow-up 26.2 ± 10.4 months) were available for the analysis. On multivariate linear regression analysis, greater DBP-CV was associated with slower decline in eGFR-EPI per year (B -0.648, p = 0.000). Likewise, the hazard ratio (HR) for dialysis inception (occurred in 9.4%) was found significantly lower with increasing DBP-CV in unadjusted and fully adjusted Cox models (HR 0.730, 95% CI 0.618 - 0.861, p = 0.000, and HR 0.678, 95% CI 0.526 - 0.874, p = 0.003, respectively). These findings suggest that DBP variability in 24-hour ABPM may be a good prognostic factor for the outcomes of CKD. Further studies are needed to determine the impact of 24-hour ABPM BPV on CKD progression and its differences from VVV.
.

  4. Scrub typhus in South India: clinical and laboratory manifestations, genetic variability, and outcome.

    Science.gov (United States)

    Varghese, George M; Janardhanan, Jeshina; Trowbridge, Paul; Peter, John V; Prakash, John A J; Sathyendra, Sowmya; Thomas, Kurien; David, Thambu S; Kavitha, M L; Abraham, Ooriapadickal C; Mathai, Dilip

    2013-11-01

    This study sought to document the clinical and laboratory manifestations, genetic variability, and outcomes of scrub typhus, an often severe infection caused by Orientia tsutsugamushi, in South India. Patients admitted to a large teaching hospital with IgM ELISA-confirmed scrub typhus were evaluated. Clinical examination with a thorough search for an eschar, laboratory testing, chest X-ray, and outcome were documented and analyzed. Additionally, a 410-bp region of the 56-kDa type-specific antigen gene of O. tsutsugamushi was sequenced and compared with isolates from other regions of Asia. Most of the 154 patients evaluated presented with fever and non-specific symptoms. An eschar was found in 86 (55%) patients. Mild hepatic involvement was seen in most, with other organ involvement including respiratory, cardiovascular, and renal. Multi-organ dysfunction was noted in 59 (38.3%), and the fatality rate was 7.8%. Hypotension requiring vasoactive agents was found to be an independent predictor of mortality (p<0.001). The phylogeny of 26 samples showed 17 (65%) clustering with the Kato-like group and eight (31%) with the Karp-like group. The presentation of scrub typhus can be variable, often non-specific, but with potentially severe multi-organ dysfunction. Prompt recognition is key to specific treatment and good outcomes. Further study of the circulating strains is essential for the development of a successful vaccine and sensitive point-of-care testing. Copyright © 2013 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  5. High Intrapatient Variability of Tacrolimus Levels and Outpatient Clinic Nonattendance Are Associated With Inferior Outcomes in Renal Transplant Patients

    Directory of Open Access Journals (Sweden)

    Dawn L. Goodall, MSc

    2017-08-01

    Conclusions. This study shows that high tacrolimus IPV and clinic nonattendance are associated with inferior allograft survival. Interventions to minimize the causes of high variability, particularly nonadherence are essential to improve long-term allograft outcomes.

  6. Intraindividual variability in reaction time predicts cognitive outcomes 5 years later.

    Science.gov (United States)

    Bielak, Allison A M; Hultsch, David F; Strauss, Esther; Macdonald, Stuart W S; Hunter, Michael A

    2010-11-01

    Building on results suggesting that intraindividual variability in reaction time (inconsistency) is highly sensitive to even subtle changes in cognitive ability, this study addressed the capacity of inconsistency to predict change in cognitive status (i.e., cognitive impairment, no dementia [CIND] classification) and attrition 5 years later. Two hundred twelve community-dwelling older adults, initially aged 64-92 years, remained in the study after 5 years. Inconsistency was calculated from baseline reaction time performance. Participants were assigned to groups on the basis of their fluctuations in CIND classification over time. Logistic and Cox regressions were used. Baseline inconsistency significantly distinguished among those who remained or transitioned into CIND over the 5 years and those who were consistently intact (e.g., stable intact vs. stable CIND, Wald (1) = 7.91, p < .01, Exp(β) = 1.49). Average level of inconsistency over time was also predictive of study attrition, for example, Wald (1) = 11.31, p < .01, Exp(β) = 1.24. For both outcomes, greater inconsistency was associated with a greater likelihood of being in a maladaptive group 5 years later. Variability based on moderately cognitively challenging tasks appeared to be particularly sensitive to longitudinal changes in cognitive ability. Mean rate of responding was a comparable predictor of change in most instances, but individuals were at greater relative risk of being in a maladaptive outcome group if they were more inconsistent rather than if they were slower in responding. Implications for the potential utility of intraindividual variability in reaction time as an early marker of cognitive decline are discussed. (c) 2010 APA, all rights reserved

  7. Cortical Contribution to Linear, Non-linear and Frequency Components of Motor Variability Control during Standing.

    Science.gov (United States)

    König Ignasiak, Niklas; Habermacher, Lars; Taylor, William R; Singh, Navrag B

    2017-01-01

    Motor variability is an inherent feature of all human movements and reflects the quality of functional task performance. Depending on the requirements of the motor task, the human sensory-motor system is thought to be able to flexibly govern the appropriate level of variability. However, it remains unclear which neurophysiological structures are responsible for the control of motor variability. In this study, we tested the contribution of cortical cognitive resources on the control of motor variability (in this case postural sway) using a dual-task paradigm and furthermore observed potential changes in control strategy by evaluating Ia-afferent integration (H-reflex). Twenty healthy subjects were instructed to stand relaxed on a force plate with eyes open and closed, as well as while trying to minimize sway magnitude and performing a "subtracting-sevens" cognitive task. In total 25 linear and non-linear parameters were used to evaluate postural sway, which were combined using a Principal Components procedure. Neurophysiological response of Ia-afferent reflex loop was quantified using the Hoffman reflex. In order to assess the contribution of the H-reflex on the sway outcome in the different standing conditions multiple mixed-model ANCOVAs were performed. The results suggest that subjects were unable to further minimize their sway, despite actively focusing to do so. The dual-task had a destabilizing effect on PS, which could partly (by 4%) be counter-balanced by increasing reliance on Ia-afferent information. The effect of the dual-task was larger than the protective mechanism of increasing Ia-afferent information. We, therefore, conclude that cortical structures, as compared to peripheral reflex loops, play a dominant role in the control of motor variability.

  8. SYNTHESIS OF THE TECHNICAL CONTROL SYSTEMS WITH VARIABLE STRUCTURE

    Directory of Open Access Journals (Sweden)

    2016-01-01

    Full Text Available Change. Also the object as a result of an adverse effect is considered. The formal problem definition of synthesis of hardy management system is considered. Model choice criteria ensemble is set. The rule of choice algorithm implementation on the basis of different reference functions is provided. The conclusion is drawn that in case of preliminary processing of the available prior data it is possible to select reference functions correctly which reflect physical processes more precisely. The mathematical description of a dynamic object on the basis of a differential equation, or its decision is provided. Defini- tion of function of a trend is given. Criteria for selection of model of damage are given. The recommendation of modifica- tion of Demark trends algorithm by means of the sliding Yazvinsky's window and a method of self-organization for in- crease of accuracy of creation of a predictive model of damage is made. It is offered to realize a model choice by means of more complex logical analysis of an observed vector in the appropriate situation. Logic-functional control task definition is given and approach to its decision is formulated. The conclusion about what the task of synthesis management system con- sists of is given. This article describes the method of synthesis of control system with variable structure provides increasing survivability control system in a significant change of the external environment, as well as the object itself from the adverse impacts.

  9. Automotive engine air intake system with variable noise control

    Science.gov (United States)

    Moenssen, David J.; Hellie, Mark D.; Koston, John D.; Shaw, Christopher E.

    2005-09-01

    Engine air intake systems are routinely tasked with delivering a specific target sound which involves meeting an overall noise level and, in many cases, desired frequency content over the entire engine speed range. In order to meet these targets, it is generally necessary to incorporate one or more reactive tuning devices, such as Helmholtz resonators, into the intake system. Traditional devices provide deep attenuation at their designed frequency, but they also introduce undesirable sideband resonances at a higher and a lower frequency. Even after the addition of several devices, it may still not be possible to match the desired intake noise targets due to their deep attenuation and sideband amplification. The subject of this work is to introduce an electronically controlled variable noise control (VNC) device for engine air intake systems which is capable of adjusting the air intake system's frequency response as commanded by the engine operating conditions. The VNC device permits the desired amount of attenuation of peaks in the air intake noise without introducing undesirable sideband resonances. In addition, because the tuning is controlled electronically, the VNC device can deliver a target-specific response using the same hardware across multiple vehicle programs.

  10. Controls of Soil Spatial Variability in a Dry Tropical Forest.

    Directory of Open Access Journals (Sweden)

    Sandeep Pulla

    Full Text Available We examined the roles of lithology, topography, vegetation and fire in generating local-scale (<1 km2 soil spatial variability in a seasonally dry tropical forest (SDTF in southern India. For this, we mapped soil (available nutrients, Al, total C, pH, moisture and texture in the top 10 cm, rock outcrops, topography, all native woody plants ≥1 cm diameter at breast height (DBH, and spatial variation in fire frequency (times burnt during the 17 years preceding soil sampling in a permanent 50-ha plot. Unlike classic catenas, lower elevation soils had lesser moisture, plant-available Ca, Cu, Mn, Mg, Zn, B, clay and total C. The distribution of plant-available Ca, Cu, Mn and Mg appeared to largely be determined by the whole-rock chemical composition differences between amphibolites and hornblende-biotite gneisses. Amphibolites were associated with summit positions, while gneisses dominated lower elevations, an observation that concurs with other studies in the region which suggest that hillslope-scale topography has been shaped by differential weathering of lithologies. Neither NO3(--N nor NH4(+-N was explained by the basal area of trees belonging to Fabaceae, a family associated with N-fixing species, and no long-term effects of fire on soil parameters were detected. Local-scale lithological variation is an important first-order control over soil variability at the hillslope scale in this SDTF, by both direct influence on nutrient stocks and indirect influence via control of local relief.

  11. The Effect of Latent Binary Variables on the Uncertainty of the Prediction of a Dichotomous Outcome Using Logistic Regression Based Propensity Score Matching.

    Science.gov (United States)

    Szekér, Szabolcs; Vathy-Fogarassy, Ágnes

    2018-01-01

    Logistic regression based propensity score matching is a widely used method in case-control studies to select the individuals of the control group. This method creates a suitable control group if all factors affecting the output variable are known. However, if relevant latent variables exist as well, which are not taken into account during the calculations, the quality of the control group is uncertain. In this paper, we present a statistics-based research in which we try to determine the relationship between the accuracy of the logistic regression model and the uncertainty of the dependent variable of the control group defined by propensity score matching. Our analyses show that there is a linear correlation between the fit of the logistic regression model and the uncertainty of the output variable. In certain cases, a latent binary explanatory variable can result in a relative error of up to 70% in the prediction of the outcome variable. The observed phenomenon calls the attention of analysts to an important point, which must be taken into account when deducting conclusions.

  12. Unpredictable Variable Prenatal Stress Programs Expression of Genes Involved in Appetite Control and Energy Expenditure

    Science.gov (United States)

    Moyer, E. L.; Al-Shayeb, B.; Baer, L. A.; Ronca, A. E.

    2016-01-01

    Exposure to stress in the womb shapes neurobiological and physiological outcomes of offspring in later life, including body weight regulation and metabolic profiles. Our previous work utilizing a centrifugation-induced hyper-gravity demonstrated significantly increased (8-15%) body mass in male, but not female, rats exposed throughout gestation to chronic 2-g from conception to birth. We reported a similar outcome in adult offspring exposed throughout gestation to Unpredictable Variable Prenatal Stress (UVPS). Here we examine gene expression changes and the plasma of animals treated with our UVPS model to identify a potential role for prenatal stress in this hypergravity programming effect. Specifically we focused on appetite control and energy expenditure pathways in prenatally stressed adult (90-day-old) male Sprague-Dawley rats.

  13. Metacognition as a Mediating Variable Between Neurocognition and Functional Outcome in First Episode Psychosis.

    Science.gov (United States)

    Davies, Geoff; Fowler, David; Greenwood, Kathryn

    2017-07-01

    Neurocognitive and functional outcome deficits have long been acknowledged in schizophrenia and neurocognition has been found to account for functional disability to a greater extent than psychopathology. Much of the variance in functional outcome however still remains unexplained and metacognition may mediate the relationship between neurocognition, functional capacity, and self-reported social and occupational function. Eighty first episode psychosis participants were recruited and completed measures of neurocognition (memory, executive function, and intelligence quotient), metacognition (Beck Cognitive Insight Scale, Metacognitive Awareness Interview), psychopathology (PANSS), and both functional capacity (UPSA) and real-life social and occupational function (The Time Use Survey). Path analyses investigated the relationships between variables through structural equation modeling. A series of path models demonstrated that metacognition partially mediates the relationship between neurocognition and functional capacity, and fully mediates the relationship between functional capacity and social and occupational function. The present study findings identify that metacognition may be critical to translating cognitive and functional skills into real-world contexts, and this relationship is found at early stages of illness. Understanding how individuals translate cognitive and functional skills into the real-world (the competence-performance gap) may offer valuable guidance to intervention programs. This finding is important to models of recovery as it suggests that intervention programs that focus on enhancing metacognition abilities may have a greater impact than traditional rehabilitation programs focusing on cognitive abilities, on social and occupational outcomes. © The Author 2016. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com

  14. S-variable approach to LMI-based robust control

    CERN Document Server

    Ebihara, Yoshio; Arzelier, Denis

    2015-01-01

    This book shows how the use of S-variables (SVs) in enhancing the range of problems that can be addressed with the already-versatile linear matrix inequality (LMI) approach to control can, in many cases, be put on a more unified, methodical footing. Beginning with the fundamentals of the SV approach, the text shows how the basic idea can be used for each problem (and when it should not be employed at all). The specific adaptations of the method necessitated by each problem are also detailed. The problems dealt with in the book have the common traits that: analytic closed-form solutions are not available; and LMIs can be applied to produce numerical solutions with a certain amount of conservatism. Typical examples are robustness analysis of linear systems affected by parametric uncertainties and the synthesis of a linear controller satisfying multiple, often  conflicting, design specifications. For problems in which LMI methods produce conservative results, the SV approach is shown to achieve greater accuracy...

  15. Detecting Major Genetic Loci Controlling Phenotypic Variability in Experimental Crosses

    Science.gov (United States)

    Rönnegård, Lars; Valdar, William

    2011-01-01

    Traditional methods for detecting genes that affect complex diseases in humans or animal models, milk production in livestock, or other traits of interest, have asked whether variation in genotype produces a change in that trait’s average value. But focusing on differences in the mean ignores differences in variability about that mean. The robustness, or uniformity, of an individual’s character is not only of great practical importance in medical genetics and food production but is also of scientific and evolutionary interest (e.g., blood pressure in animal models of heart disease, litter size in pigs, flowering time in plants). We describe a method for detecting major genes controlling the phenotypic variance, referring to these as vQTL. Our method uses a double generalized linear model with linear predictors based on probabilities of line origin. We evaluate our method on simulated F2 and collaborative cross data, and on a real F2 intercross, demonstrating its accuracy and robustness to the presence of ordinary mean-controlling QTL. We also illustrate the connection between vQTL and QTL involved in epistasis, explaining how these concepts overlap. Our method can be applied to a wide range of commonly used experimental crosses and may be extended to genetic association more generally. PMID:21467569

  16. Prenatal emotion management improves obstetric outcomes: a randomized control study.

    Science.gov (United States)

    Huang, Jian; Li, He-Jiang; Wang, Jue; Mao, Hong-Jing; Jiang, Wen-Ying; Zhou, Hong; Chen, Shu-Lin

    2015-01-01

    Negative emotions can cause a number of prenatal problems and disturb obstetric outcomes. We determined the effectiveness of prenatal emotional management on obstetric outcomes in nulliparas. All participants completed the PHQ-9 at the baseline assessment. Then, the participants were randomly assigned to the emotional management (EM) and usual care (UC) groups. The baseline evaluation began at 31 weeks gestation and the participants were followed up to 42 days postpartum. Each subject in the EM group received an extra EM program while the participants in the UC groups received routine prenatal care and education only. The PHQ-9 and Edinburgh Postnatal Depression scale (EPDS) were used for assessment. The EM group had a lower PHQ-9 score at 36 weeks gestation, and 7 and 42 days after delivery (P Prenatal EM intervention could control anxiety and depressive feelings in nulliparas, and improve obstetric outcomes. It may serve as an innovative approach to reduce the cesarean section rate in China.

  17. Deciphering factors controlling groundwater arsenic spatial variability in Bangladesh

    Science.gov (United States)

    Tan, Z.; Yang, Q.; Zheng, C.; Zheng, Y.

    2017-12-01

    Elevated concentrations of geogenic arsenic in groundwater have been found in many countries to exceed 10 μg/L, the WHO's guideline value for drinking water. A common yet unexplained characteristic of groundwater arsenic spatial distribution is the extensive variability at various spatial scales. This study investigates factors influencing the spatial variability of groundwater arsenic in Bangladesh to improve the accuracy of models predicting arsenic exceedance rate spatially. A novel boosted regression tree method is used to establish a weak-learning ensemble model, which is compared to a linear model using a conventional stepwise logistic regression method. The boosted regression tree models offer the advantage of parametric interaction when big datasets are analyzed in comparison to the logistic regression. The point data set (n=3,538) of groundwater hydrochemistry with 19 parameters was obtained by the British Geological Survey in 2001. The spatial data sets of geological parameters (n=13) were from the Consortium for Spatial Information, Technical University of Denmark, University of East Anglia and the FAO, while the soil parameters (n=42) were from the Harmonized World Soil Database. The aforementioned parameters were regressed to categorical groundwater arsenic concentrations below or above three thresholds: 5 μg/L, 10 μg/L and 50 μg/L to identify respective controlling factors. Boosted regression tree method outperformed logistic regression methods in all three threshold levels in terms of accuracy, specificity and sensitivity, resulting in an improvement of spatial distribution map of probability of groundwater arsenic exceeding all three thresholds when compared to disjunctive-kriging interpolated spatial arsenic map using the same groundwater arsenic dataset. Boosted regression tree models also show that the most important controlling factors of groundwater arsenic distribution include groundwater iron content and well depth for all three

  18. Variability of sap flow on forest hillslopes: patterns and controls

    Science.gov (United States)

    Hassler, Sibylle; Blume, Theresa

    2013-04-01

    Sap flow in trees is an essential variable in integrated studies of hydrologic fluxes. It gives indication of transpiration rates for single trees and, with a suitable method of upscaling, for whole stands. This information is relevant for hydrologic and climate models, especially for the prediction of change in water fluxes in the soil-plant-atmosphere continuum under climate change. To this end, we do not only need knowledge concerning the response of sapflow to atmospheric forcing but also an understanding of the main controls on its spatial variability. Our study site consists of several subcatchments of the Attert basin in Luxembourg underlain by schists of the Ardennes massif. Within these subcatchments we measure sap flow in more than 20 trees on a range of forested hillslopes covered by a variety of temperate deciduous tree species such as beech, oak, hornbeam and maple as well as conifers such as firs. Our sap flow sensors are based on the heat pulse velocity method and consist of three needles, one needle acting as the heating device and the other two holding three thermistors each, enabling us to simultaneously measure sap flow velocity at three different depths within the tree. In close proximity to the trees we collect additional data on soil moisture, matric potential and groundwater levels. First results show that the sensor design seems promising for an upscaling of the measured sap flow velocities to sap flow at the tree level. The maximum depth of actively used sapwood as well as the decrease in sap flow velocity with increasing depth in the tree can be determined by way of the three thermistors. Marked differences in sap flow velocity profiles are visible between the different species, resulting in differences in sap flow for trees of similar diameter. We examine the range of tree sap flow values and variation due to species, size class, slope position and exposition and finally relate them to the dynamics of soil moisture conditions with the

  19. Parental Decisional Regret after Primary Distal Hypospadias Repair: Family and Surgery Variables, and Repair Outcomes.

    Science.gov (United States)

    Ghidini, Filippo; Sekulovic, Sasa; Castagnetti, Marco

    2016-03-01

    Decisional regret is defined as distress after making a health care choice and can be an issue for parents electing distal hypospadias repair for their sons. We assessed the influence on decisional regret of variables related to the family, surgery and outcomes. Charts for 372 patients undergoing primary distal hypospadias repair between 2005 and 2012 were reviewed, and validated questionnaires, including the Decisional Regret Scale, Pediatric Penile Perception Score and Dysfunctional Voiding and Incontinence Scoring System, were administered to parents. Data were available for 172 of 372 families (response rate 46.2%). Of 323 parents 128 (39.6%) presented with moderately strong decisional regret, with good agreement within couples. Predictors of decisional regret included intermediate parental educational level (OR 3.19, 95% CI 1.52-6.69), patient not being the first born (OR 2.01, 95% CI 1.07-3.78), family history of hypospadias (OR 4.42, 95% CI 1.96-9.97), initial desire to avoid surgery (OR 2.07, 95% CI 1.04-4.12), younger age at followup (OR 0.81, 95% CI 0.72-0.91), presence of lower urinary tract symptoms (OR 4.92, 95% CI 1.53-15.81) and lower Pediatric Penile Perception Score (OR 0.86, 95% CI 0.75-0.99). Decisional regret was unrelated to parental desire to avoid circumcision, surgical variables, development of complications and duration of followup. Decisional regret is a problem in a significant proportion of parents electing distal hypospadias repair for their sons. In our experience family variables seemed to be predictors of decisional regret, while surgical variables did not. Predictors of decisional regret included worse parental perception of penile appearance and the presence of lower urinary tract symptoms. However, the latter could be unrelated to surgery. Irrespective of the duration of followup, decisional regret seems decreased in parents of older patients. Copyright © 2016 American Urological Association Education and Research, Inc

  20. Optimal management strategies in variable environments: Stochastic optimal control methods

    Science.gov (United States)

    Williams, B.K.

    1985-01-01

    Dynamic optimization was used to investigate the optimal defoliation of salt desert shrubs in north-western Utah. Management was formulated in the context of optimal stochastic control theory, with objective functions composed of discounted or time-averaged biomass yields. Climatic variability and community patterns of salt desert shrublands make the application of stochastic optimal control both feasible and necessary. A primary production model was used to simulate shrub responses and harvest yields under a variety of climatic regimes and defoliation patterns. The simulation results then were used in an optimization model to determine optimal defoliation strategies. The latter model encodes an algorithm for finite state, finite action, infinite discrete time horizon Markov decision processes. Three questions were addressed: (i) What effect do changes in weather patterns have on optimal management strategies? (ii) What effect does the discounting of future returns have? (iii) How do the optimal strategies perform relative to certain fixed defoliation strategies? An analysis was performed for the three shrub species, winterfat (Ceratoides lanata), shadscale (Atriplex confertifolia) and big sagebrush (Artemisia tridentata). In general, the results indicate substantial differences among species in optimal control strategies, which are associated with differences in physiological and morphological characteristics. Optimal policies for big sagebrush varied less with variation in climate, reserve levels and discount rates than did either shadscale or winterfat. This was attributed primarily to the overwintering of photosynthetically active tissue and to metabolic activity early in the growing season. Optimal defoliation of shadscale and winterfat generally was more responsive to differences in plant vigor and climate, reflecting the sensitivity of these species to utilization and replenishment of carbohydrate reserves. Similarities could be seen in the influence of both

  1. Student understanding of control of variables: Deciding whether or not a variable influences the behavior of a system

    Science.gov (United States)

    Boudreaux, Andrew; Shaffer, Peter S.; Heron, Paula R. L.; McDermott, Lillian C.

    2008-02-01

    The ability of adult students to reason on the basis of the control of variables was the subject of an extended investigation. This paper describes the part of the study that focused on the reasoning required to decide whether or not a given variable influences the behavior of a system. The participants were undergraduates taking introductory Physics and K-8 teachers studying physics and physical science in inservice institutes and workshops. Although most of the students recognized the need to control variables, many had significant difficulty with the underlying reasoning. The results indicate serious shortcomings in the preparation of future scientists and in the education of a scientifically literate citizenry. There are also strong implications for the professional development of teachers, many of whom are expected to teach control of variables to young students.

  2. Outcomes of splenectomy in patients with common variable immunodeficiency (CVID): a survey of 45 patients

    Science.gov (United States)

    Wong, G K; Goldacker, S; Winterhalter, C; Grimbacher, B; Chapel, H; Lucas, M; Alecsandru, D; McEwen, D; Quinti, I; Martini, H; Schmidt, R E; Ernst, D; Espanol, T; Vidaller, A; Carbone, J; Fernandez-Cruz, E; Lougaris, V; Plebani, A; Kutukculer, N; Gonzalez-Granado, L I; Contreras, R; Kiani-Alikhan, S; Ibrahim, M A A; Litzman, J; Jones, A; Gaspar, H B; Hammarstrom, L; Baumann, U; Warnatz, K; Huissoon, A P

    2013-01-01

    Splenectomy has been used in patients with common variable immunodeficiency disorders (CVID), mainly in the context of refractory autoimmune cytopenia and suspected lymphoma, but there are understandable concerns about the potential of compounding an existing immunodeficiency. With increasing use of rituximab as an alternative treatment for refractory autoimmune cytopenia, the role of splenectomy in CVID needs to be re-examined. This retrospective study provides the largest cohesive data set to date describing the outcome of splenectomy in 45 CVID patients in the past 40 years. Splenectomy proved to be an effective long-term treatment in 75% of CVID patients with autoimmune cytopenia, even in some cases when rituximab had failed. Splenectomy does not worsen mortality in CVID and adequate immunoglobulin replacement therapy appears to play a protective role in overwhelming post-splenectomy infections. Future trials comparing the effectiveness and safety of rituximab and splenectomy are needed to provide clearer guidance on the second-line management of autoimmune cytopenia in CVID. PMID:23480186

  3. Design and Calibration of a Transformer Controlled Variable ...

    African Journals Online (AJOL)

    A new approach for the design and construction of a variable rainfall simulator using an auto transformer which is aimed at soil erosion research was explored. The method involves using a water pump, a variable voltage regulator and a set of nozzles for the simulation of rainfall. It was found that the variation of rainfall ...

  4. Vector Control Algorithm for Electric Vehicle AC Induction Motor Based on Improved Variable Gain PID Controller

    Directory of Open Access Journals (Sweden)

    Gang Qin

    2015-01-01

    Full Text Available The acceleration performance of EV, which affects a lot of performances of EV such as start-up, overtaking, driving safety, and ride comfort, has become increasingly popular in recent researches. An improved variable gain PID control algorithm to improve the acceleration performance is proposed in this paper. The results of simulation with Matlab/Simulink demonstrate the effectiveness of the proposed algorithm through the control performance of motor velocity, motor torque, and three-phase current of motor. Moreover, it is investigated that the proposed controller is valid by comparison with the other PID controllers. Furthermore, the AC induction motor experiment set is constructed to verify the effect of proposed controller.

  5. Blood pressure variability in relation to outcome in the International Database of Ambulatory blood pressure in relation to Cardiovascular Outcome

    DEFF Research Database (Denmark)

    Stolarz-Skrzypek, Katarzyna; Thijs, Lutgarde; Richart, Tom

    2010-01-01

    Ambulatory blood pressure (BP) monitoring provides information not only on the BP level but also on the diurnal changes in BP. In the present review, we summarized the main findings of the International Database on Ambulatory BP in relation to Cardiovascular Outcome (IDACO) with regard to risk...

  6. What controls the atmospheric methane seasonal variability over India?

    KAUST Repository

    Guha, Tania; Tiwari, Yogesh K.; Valsala, Vinu; Lin, Xin; Ramonet, Michel; Mahajan, Anoop; Datye, Amey; Kumar, K. Ravi

    2017-01-01

    Atmospheric CH4 observations from two ground-based stations within Indian subcontinent, namely, Sinhagad (SNG) and Cape Rama station (CRI) showed a strong seasonality with a minima (∼1800 ± 20 ppb) during southwest monsoon (SWM; i.e. June–September, JJAS) and a maxima (2000 ± 30 ppb) during northeast monsoon (NEM i.e. December–February, DJF) with a peak-to-peak seasonality close to 200 ppb. The Indian summer (winter) monsoon is characterized with strong southwesterly (northeasterly) winds of oceanic origin at the surface level and strong easterly (westerly) jet streams aloft. The monsoon dynamics has pronounced impact on CH4 variability over India and is analyzed with winds, Lagrangian trajectories, and 3-dimentional distributions of CH4 simulated by a general circulation model. The model simulations suggest a consistent annual vertical structure (mean and sub-seasonal uncertainty) of CH4 over India with a stark contrast in concentration from summer to winter at surface levels (below 750 mb) in confirmation with what is identified by the ground-based observations. During SWM (NEM) the air with comparatively lower (higher) CH4 concentrations from southern (northern) hemisphere reduces the CH4 over India by 1814 ± 26 ppb (enhances by 1950 ± 51 ppb). The contribution of local fluxes to this seasonality appears to be albeit weak as the synthesized CH4 fluxes (from EDGAR dataset) of the Indian peninsula itself show a peak in summer and a dip in winter. Similar property of CH4 is also common to nearby oceanic region (i.e. over Arabian Sea, 1765 ± 10 ppb during summer) suggesting the role of monsoon dynamics as the controlling factor. Further the mixing and convection carries the CH4 to the upper atmosphere and advect inward or outward aloft according the seasonal monsoon dynamics.

  7. What controls the atmospheric methane seasonal variability over India?

    KAUST Repository

    Guha, Tania

    2017-11-28

    Atmospheric CH4 observations from two ground-based stations within Indian subcontinent, namely, Sinhagad (SNG) and Cape Rama station (CRI) showed a strong seasonality with a minima (∼1800 ± 20 ppb) during southwest monsoon (SWM; i.e. June–September, JJAS) and a maxima (2000 ± 30 ppb) during northeast monsoon (NEM i.e. December–February, DJF) with a peak-to-peak seasonality close to 200 ppb. The Indian summer (winter) monsoon is characterized with strong southwesterly (northeasterly) winds of oceanic origin at the surface level and strong easterly (westerly) jet streams aloft. The monsoon dynamics has pronounced impact on CH4 variability over India and is analyzed with winds, Lagrangian trajectories, and 3-dimentional distributions of CH4 simulated by a general circulation model. The model simulations suggest a consistent annual vertical structure (mean and sub-seasonal uncertainty) of CH4 over India with a stark contrast in concentration from summer to winter at surface levels (below 750 mb) in confirmation with what is identified by the ground-based observations. During SWM (NEM) the air with comparatively lower (higher) CH4 concentrations from southern (northern) hemisphere reduces the CH4 over India by 1814 ± 26 ppb (enhances by 1950 ± 51 ppb). The contribution of local fluxes to this seasonality appears to be albeit weak as the synthesized CH4 fluxes (from EDGAR dataset) of the Indian peninsula itself show a peak in summer and a dip in winter. Similar property of CH4 is also common to nearby oceanic region (i.e. over Arabian Sea, 1765 ± 10 ppb during summer) suggesting the role of monsoon dynamics as the controlling factor. Further the mixing and convection carries the CH4 to the upper atmosphere and advect inward or outward aloft according the seasonal monsoon dynamics.

  8. Soft Tissue Sarcoma: A Prognostic Variables and Treatment Outcomes after Chemo - Radiotherapy and Conservative Surgery

    International Nuclear Information System (INIS)

    Abaza, A.; El-Shanshoury, H.

    2015-01-01

    Soft tissue sarcomas (STS) constitute a group of rare and heterogeneous cancers, that diverse a wide spectrum of histology and varied clinical behavior. The aim was to study, retrospectively the clinico-epidemiologic manifestation, response to therapy and prognostic factors of retroperitoneal (RPS), extremity and other STS patients treated with conservative surgery plus chemo - radiotherapy (CRT) attending the Pediatric Oncology Clinic, National Cancer Institute (NCI), Cairo University during 6 years period (inclusive). Files of 66 STS patients were revised for history, staging, investigations, treatment modalities and outcome of therapy. Their ages ranged from 6 months to 21 years. The male to female ratio was 1.87:1. Most of the patients belong to stage 3 and 1. Radiotherapy (RTH) and surgery remains the backbone of the multi - modality treatment plan. Complete remission (CR) was obtained in 80.3% of STS patients. Meanwhile, 6% of cases had disease progression and 6% died. The 2 - years overall survival rate (OS) and Disease - free survivals (DFS) we re 74.2% and 57.6% respectively. However, 20.8% of patients develop relapse>2 years after the end of treatment. Age at diagnosis, stage of the disease, tumor mass, pathological subtype and the RTH used were statistically significant prognostic variables affecting survival. Finally, the use of RTH in the treatment of STS gives positive impact on the survival of patients. Recommendation regarding further studies would be required to identify methods of increasing the radiation dose selectively. Also, using the newly developed radiation technologies to make dose escalation and sparing normal tissue

  9. Neutropenia in Patients with Common Variable Immunodeficiency: a Rare Event Associated with Severe Outcome.

    Science.gov (United States)

    Guffroy, Aurélien; Mourot-Cottet, Rachel; Gérard, Laurence; Gies, Vincent; Lagresle, Chantal; Pouliet, Aurore; Nitschké, Patrick; Hanein, Sylvain; Bienvenu, Boris; Chanet, Valérie; Donadieu, Jean; Gardembas, Martine; Karmochkine, Marina; Nove-Josserand, Raphaele; Martin, Thierry; Poindron, Vincent; Soulas-Sprauel, Pauline; Rieux-Laucat, Fréderic; Fieschi, Claire; Oksenhendler, Eric; André-Schmutz, Isabelle; Korganow, Anne-Sophie

    2017-10-01

    Common variable immunodeficiency (CVID) is characterized by infections and hypogammaglobulinemia. Neutropenia is rare during CVID. The French DEFI study enrolled patients with primary hypogammaglobulinemia. Patients with CVID and neutropenia were retrospectively analyzed. Among 473 patients with CVID, 16 patients displayed neutropenia (lowest count [0-1400]*10 6 /L). Sex ratio (M/F) was 10/6. Five patients died during the follow-up (11 years) with an increased percentage of deaths compared to the whole DEFI group (31.3 vs 3.4%, P < 0.05). Neutropenia was diagnosed for 10 patients before 22 years old. The most frequent symptoms, except infections, were autoimmune cytopenia, i.e., thrombopenia or anemia (11/16). Ten patients were affected with lymphoproliferative diseases. Two patients were in the infection only group and the others belonged to one or several other CVID groups. The median level of IgG was 2.6 g/L [0.35-4.4]. Most patients presented increased numbers of CD21 low CD38 low B cell, as already described in CVID autoimmune cytopenia group. Neutropenia was considered autoimmune in 11 cases. NGS for 52 genes of interest was performed on 8 patients. No deleterious mutations were found in LRBA, CTLA4, and PIK3. More than one potentially damaging variant in other genes associated with CVID were present in most patients arguing for a multigene process. Neutropenia is generally associated with another cytopenia and presumably of autoimmune origin during CVID. In the DEFI study, neutropenia is coupled with more severe clinical outcomes. It appears as an "alarm bell" considering patients' presentation and the high rate of deaths. Whole exome sequencing diagnosis should improve management.

  10. Variable Camber Continuous Aerodynamic Control Surfaces and Methods for Active Wing Shaping Control

    Science.gov (United States)

    Nguyen, Nhan T. (Inventor)

    2016-01-01

    An aerodynamic control apparatus for an air vehicle improves various aerodynamic performance metrics by employing multiple spanwise flap segments that jointly form a continuous or a piecewise continuous trailing edge to minimize drag induced by lift or vortices. At least one of the multiple spanwise flap segments includes a variable camber flap subsystem having multiple chordwise flap segments that may be independently actuated. Some embodiments also employ a continuous leading edge slat system that includes multiple spanwise slat segments, each of which has one or more chordwise slat segment. A method and an apparatus for implementing active control of a wing shape are also described and include the determination of desired lift distribution to determine the improved aerodynamic deflection of the wings. Flap deflections are determined and control signals are generated to actively control the wing shape to approximate the desired deflection.

  11. Active queue management controller design for TCP communication networks: Variable structure control approach

    International Nuclear Information System (INIS)

    Chen, C.-K.; Liao, T.-L.; Yan, J.-J.

    2009-01-01

    On the basis of variable structure control (VSC), an active queue management (AQM) controller is presented for a class of TCP communication networks. In the TCP/IP networks, the packet drop probability is limited between 0 and 1. Therefore, we modeled TCP/AQM as a rate-based non-linear system with a saturated input. The objective of the VSC-based AQM controller is to achieve the desired queue size and to guarantee the asymptotic stability of the closed-loop TCP non-linear system with saturated input. The performance and effectiveness of the proposed control law are then validated for different network scenarios through numerical simulations in both MATLAB and Network Simulator-2 (NS-2). Both sets of simulation results have confirmed that the proposed scheme outperforms other AQM schemes.

  12. Active queue management controller design for TCP communication networks: Variable structure control approach

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.-K. [Department of Engineering Science, National Cheng Kung University, Tainan 701, Taiwan (China); Liao, T.-L. [Department of Engineering Science, National Cheng Kung University, Tainan 701, Taiwan (China)], E-mail: tlliao@mail.ncku.edu; Yan, J.-J. [Department of Computer and Communication, Shu-Te University, Kaohsiung 824, Taiwan (China)

    2009-04-15

    On the basis of variable structure control (VSC), an active queue management (AQM) controller is presented for a class of TCP communication networks. In the TCP/IP networks, the packet drop probability is limited between 0 and 1. Therefore, we modeled TCP/AQM as a rate-based non-linear system with a saturated input. The objective of the VSC-based AQM controller is to achieve the desired queue size and to guarantee the asymptotic stability of the closed-loop TCP non-linear system with saturated input. The performance and effectiveness of the proposed control law are then validated for different network scenarios through numerical simulations in both MATLAB and Network Simulator-2 (NS-2). Both sets of simulation results have confirmed that the proposed scheme outperforms other AQM schemes.

  13. Variable versus conventional lung protective mechanical ventilation during open abdominal surgery (PROVAR): a randomised controlled trial

    NARCIS (Netherlands)

    Spieth, P. M.; Güldner, A.; Uhlig, C.; Bluth, T.; Kiss, T.; Conrad, C.; Bischlager, K.; Braune, A.; Huhle, R.; Insorsi, A.; Tarantino, F.; Ball, L.; Schultz, M. J.; Abolmaali, N.; Koch, T.; Pelosi, P.; Gama de Abreu, M.

    2018-01-01

    Experimental studies showed that controlled variable ventilation (CVV) yielded better pulmonary function compared to non-variable ventilation (CNV) in injured lungs. We hypothesized that CVV improves intraoperative and postoperative respiratory function in patients undergoing open abdominal surgery.

  14. Coral bleaching pathways under the control of regional temperature variability

    Science.gov (United States)

    Langlais, C. E.; Lenton, A.; Heron, S. F.; Evenhuis, C.; Sen Gupta, A.; Brown, J. N.; Kuchinke, M.

    2017-11-01

    Increasing sea surface temperatures (SSTs) are predicted to adversely impact coral populations worldwide through increasing thermal bleaching events. Future bleaching is unlikely to be spatially uniform. Therefore, understanding what determines regional differences will be critical for adaptation management. Here, using a cumulative heat stress metric, we show that characteristics of regional SST determine the future bleaching risk patterns. Incorporating observed information on SST variability, in assessing future bleaching risk, provides novel options for management strategies. As a consequence, the known biases in climate model variability and the uncertainties in regional warming rate across climate models are less detrimental than previously thought. We also show that the thresholds used to indicate reef viability can strongly influence a decision on what constitutes a potential refugia. Observing and understanding the drivers of regional variability, and the viability limits of coral reefs, is therefore critical for making meaningful projections of coral bleaching risk.

  15. Inferior outcomes for black children with high risk acute lymphoblastic leukemia and the impact of socioeconomic variables.

    Science.gov (United States)

    Walsh, Alexandra; Chewning, Joseph; Li, Xuelin; Dai, Chen; Whelan, Kimberly; Madan-Swain, Avi; Waterbor, John; Baskin, Monica L; Goldman, Frederick D

    2017-02-01

    While significant improvements have been made for children with acute lymphoblastic leukemia (ALL) in the United States over the past 20 years, black patients continue to have inferior outcomes. The full impact of socioeconomic variables on outcomes in this minority population is not entirely understood. Disease characteristics, demographic, and socioeconomic status (SES) variables were collected on black (n = 44) and white (n = 178) patients diagnosed at the University of Alabama at Birmingham. Cox proportional hazard regression was used to evaluate the influence of SES and insurance status on survival. As a cohort, 5-year overall survival (OS) was 87% (82-91%), with a median follow-up of 99 months. In univariable analysis, black race was not significantly associated with a higher risk of death or relapse and death. White and black patients with standard-risk leukemia had excellent outcomes, with 97% (91-99%) and 96% (75-99%) 5-year OS, respectively. In contrast, for high-risk disease, white patients had a statistically significant improved 5-year OS rates compared with black patients (79% [68-87%] vs. 52% [28-72%]). Black children were more likely to have public insurance, and, in multivariable analysis, this was associated with a trend toward an improved outcome. Black patients also had poorer census tract-level SES parameters, but these variables were not associated with survival. Our study demonstrates significantly inferior outcomes for black children with high-risk leukemia. These outcome disparities were not related to SES variables, including poverty or private insurance coverage, suggesting the involvement of other factors and highlighting the need for a prospective investigative analysis. © 2016 Wiley Periodicals, Inc.

  16. Negative Control Outcomes and the Analysis of Standardized Mortality Ratios.

    Science.gov (United States)

    Richardson, David B; Keil, Alexander P; Tchetgen Tchetgen, Eric; Cooper, Glinda

    2015-09-01

    In occupational cohort mortality studies, epidemiologists often compare the observed number of deaths in the cohort to the expected number obtained by multiplying person-time accrued in the study cohort by the mortality rate in an external reference population. Interpretation of the result may be difficult due to noncomparability of the occupational cohort and reference population with respect to unmeasured risk factors for the outcome of interest. We describe an approach to estimate an adjusted standardized mortality ratio (aSMR) to control for such bias. The approach draws on methods developed for the use of negative control outcomes. Conditions necessary for unbiased estimation are described, as well as looser conditions necessary for bias reduction. The approach is illustrated using data on bladder cancer mortality among male Oak Ridge National Laboratory workers. The SMR for bladder cancer was elevated among hourly-paid males (SMR = 1.9; 95% confidence interval [CI] = 1.3, 2.7) but not among monthly-paid males (SMR = 1.0; 95% CI = 0.67, 1.3). After indirect adjustment using the proposed approach, the mortality ratios were similar in magnitude among hourly- and monthly-paid men (aSMR = 2.2; 95% CI = 1.5, 3.2; and, aSMR = 2.0; 95% CI = 1.4, 2.8, respectively). The proposed adjusted SMR offers a complement to typical SMR analyses.

  17. Pitch Angle Control for Variable Speed Wind Turbines

    Directory of Open Access Journals (Sweden)

    Mouna Ben Smida

    2015-08-01

    Full Text Available Abstract.Pitch control is a practical technique for power regulation above the rated wind speed it is considered as the most efficient and popular power control method. As conventional pitch control usually use PI controller, the mathematical model of the system should be known well.This paper deals with the operation and the control of the direct driven permanent magnet synchronous generator (PMSG.Different conventional strategies of pitch angle control are described and validated through simulation results under Matlab\\Simulink.

  18. Characteristics of patients in routine psycho-oncological care, and changes in outcome variables during and after their treatment.

    Science.gov (United States)

    Garssen, Bert; Van der Lee, Marije; Van der Poll, Amber; Ranchor, Adelita V; Sanderman, Robbert; Schroevers, Maya J

    2016-10-01

    The primary aim of this study was to determine the characteristics of clients and interventions in routine psycho-oncological care. The secondary aim was to determine the course of symptomatology during and after the psychological interventions. During a period of nine months, all clients who sought help in one of the seven psycho-oncological care institutes in the Netherlands were approached to participate in the present study (N = 483). Information was gathered with respect to demographic and medical characteristics, and type and duration of the interventions. In addition, depression, anxiety, well-being, quality of life, fatigue and daily function were determined before interventions and three and nine months later. Compared to the Dutch cancer population, patients in psycho-oncological care were more often young and female. Compared to the general Dutch population, they were highly educated and were more likely to have a partner. Clinical levels of depression, anxiety and/or fatigue were found among 83% of the patients. After three months, only 23% had completed their intervention; this figure was 62% after nine months. Symptoms decreased significantly for all outcome variables. An importance difference with randomised controlled trials is the low session frequency and the long intervention time of patients in clinical care.

  19. A Controlled Study of Variables Related to Counseling Center Use.

    Science.gov (United States)

    Bosmajian, C. Perry, Jr.; Mattson, Robert E.

    1980-01-01

    Investigated the utility of several variables in discriminating between students who seek counseling and those who do not. Interaction between personal adjustment and help-seeking status was also examined. Alternate sources of help, counseling usefulness, and perceived severity of help-seeker pathology descriminated seekers from nonseekers.…

  20. High-performance control of continuously variable transmissions

    NARCIS (Netherlands)

    Meulen, van der S.H.

    2010-01-01

    Nowadays, developments with respect to the pushbelt continuously variable transmission (CVT) are mainly directed towards a reduction of the fuel consumption of a vehicle. The fuel consumption of a vehicle is affected by the variator of the CVT, which transfers the torque and varies the transmission

  1. Optimal control of a variable spin speed CMG system for space vehicles. [Control Moment Gyros

    Science.gov (United States)

    Liu, T. C.; Chubb, W. B.; Seltzer, S. M.; Thompson, Z.

    1973-01-01

    Many future NASA programs require very high accurate pointing stability. These pointing requirements are well beyond anything attempted to date. This paper suggests a control system which has the capability of meeting these requirements. An optimal control law for the suggested system is specified. However, since no direct method of solution is known for this complicated system, a computation technique using successive approximations is used to develop the required solution. The method of calculus of variations is applied for estimating the changes of index of performance as well as those constraints of inequality of state variables and terminal conditions. Thus, an algorithm is obtained by the steepest descent method and/or conjugate gradient method. Numerical examples are given to show the optimal controls.

  2. Reduction in camera-specific variability in [{sup 123}I]FP-CIT SPECT outcome measures by image reconstruction optimized for multisite settings: impact on age-dependence of the specific binding ratio in the ENC-DAT database of healthy controls

    Energy Technology Data Exchange (ETDEWEB)

    Buchert, Ralph; Lange, Catharina [Charite - Universitaetsmedizin Berlin, Department of Nuclear Medicine, Berlin (Germany); Kluge, Andreas; Bronzel, Marcus [ABX-CRO advanced pharmaceutical services Forschungsgesellschaft m.b.H., Dresden (Germany); Tossici-Bolt, Livia [University Hospital Southampton NHS Foundation Trust, Department of Medical Physics, Southampton (United Kingdom); Dickson, John [University College London Hospital NHS Foundation Trust, Institute of Nuclear Medicine, London (United Kingdom); Asenbaum, Susanne [Medical University of Vienna, Department of Nuclear Medicine, Vienna (Austria); Booij, Jan [University of Amsterdam, Department of Nuclear Medicine, Academic Medical Centre, Amsterdam (Netherlands); Kapucu, L. Oezlem Atay [Gazi University, Department of Nuclear Medicine, Faculty of Medicine, Ankara (Turkey); Svarer, Claus [Rigshospitalet and University of Copenhagen, Neurobiology Research Unit, Copenhagen (Denmark); Koulibaly, Pierre-Malick [University of Nice-Sophia Antipolis, Nuclear Medicine Department, Centre Antoine Lacassagne, Nice (France); Nobili, Flavio [University of Genoa, Department of Neuroscience (DINOGMI), Clinical Neurology Unit, Genoa (Italy); Pagani, Marco [CNR, Institute of Cognitive Sciences and Technologies, Rome (Italy); Karolinska Hospital, Department of Nuclear Medicine, Stockholm (Sweden); Sabri, Osama [University of Leipzig, Department of Nuclear Medicine, Leipzig (Germany); Sera, Terez [University of Szeged, Department of Nuclear Medicine and Euromedic Szeged, Szeged (Hungary); Tatsch, Klaus [Municipal Hospital of Karlsruhe Inc, Department of Nuclear Medicine, Karlsruhe (Germany); Borght, Thierry vander [CHU Namur, IREC, Nuclear Medicine Division, Universite catholique de Louvain, Yvoir (Belgium); Laere, Koen van [University Hospital and K.U. Leuven, Nuclear Medicine, Leuven (Belgium); Varrone, Andrea [Karolinska University Hospital, Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet, Stockholm (Sweden); Iida, Hidehiro [National Cerebral and Cardiovascular Center - Research Institute, Osaka (Japan)

    2016-07-15

    Quantitative estimates of dopamine transporter availability, determined with [{sup 123}I]FP-CIT SPECT, depend on the SPECT equipment, including both hardware and (reconstruction) software, which limits their use in multicentre research and clinical routine. This study tested a dedicated reconstruction algorithm for its ability to reduce camera-specific intersubject variability in [{sup 123}I]FP-CIT SPECT. The secondary aim was to evaluate binding in whole brain (excluding striatum) as a reference for quantitative analysis. Of 73 healthy subjects from the European Normal Control Database of [{sup 123}I]FP-CIT recruited at six centres, 70 aged between 20 and 82 years were included. SPECT images were reconstructed using the QSPECT software package which provides fully automated detection of the outer contour of the head, camera-specific correction for scatter and septal penetration by transmission-dependent convolution subtraction, iterative OSEM reconstruction including attenuation correction, and camera-specific ''to kBq/ml'' calibration. LINK and HERMES reconstruction were used for head-to-head comparison. The specific striatal [{sup 123}I]FP-CIT binding ratio (SBR) was computed using the Southampton method with binding in the whole brain, occipital cortex or cerebellum as the reference. The correlation between SBR and age was used as the primary quality measure. The fraction of SBR variability explained by age was highest (1) with QSPECT, independently of the reference region, and (2) with whole brain as the reference, independently of the reconstruction algorithm. QSPECT reconstruction appears to be useful for reduction of camera-specific intersubject variability of [{sup 123}I]FP-CIT SPECT in multisite and single-site multicamera settings. Whole brain excluding striatal binding as the reference provides more stable quantitative estimates than occipital or cerebellar binding. (orig.)

  3. Cerebrovascular accidents after percutaneous coronary interventions from 2002 to 2014: Incidence, outcomes, and associated variables.

    Science.gov (United States)

    Didier, Romain; Gaglia, Michael A; Koifman, Edward; Kiramijyan, Sarkis; Negi, Smita I; Omar, Al Fazir; Gai, Jiaxing; Torguson, Rebecca; Pichard, Augusto D; Waksman, Ron

    2016-02-01

    Cerebrovascular accident (CVA) and transient ischemic attack (TIA) related to percutaneous coronary intervention (PCI) are relatively rare complications, but they are associated with high morbidity and mortality. Given the evolution of both CVA risk and PCI techniques over time, this study was conducted to evaluate trends in CVA and TIA associated with PCI and to identify variables associated with neurologic events. Consecutive patients undergoing PCI at the Washington Hospital Center between January 2002 and June 2015 were included. Prespecified data were prospectively collected, including baseline and procedural characteristics, in-hospital outcomes, and 1-year mortality. The subjects who had a CVA or TIA during or immediately after PCI were compared with those without procedure-associated CVA or TIA. Overall, 25,626 patients were included in the study. The mean age was 65.0 ± 12.4 years, 16,949 (65.2%) were male, and 7,436 (28.6%) were African American. From 2002 to 2015, 110 neurologic events post-PCI were diagnosed (0.43%); this included 86 CVAs (0.34%) and 24 TIAs (0.09%). The annual rate of postprocedural neurologic events was 0.42% ± 0.12%. There were significant changes in baseline risk factors over time, with increasing age, incidence of insulin-dependent diabetes, and chronic kidney disease. Patients with neurologic events were more often African American (43.6% vs 28.6%, P < .001) with prior history of CVA (24.5% vs 7.8%, P < .001), chronic renal insufficiency (26.6% vs 15.2%, P < .001), and insulin-dependent diabetes (19.1% vs 12.4%, P = .03). Acute myocardial infarction (56% vs 30.4%, P < .001) and cardiogenic shock (20.2% vs 3%, P < .001) were also more common among patients with neurologic events post-PCI. After multivariable adjustment, use of an intraaortic balloon pump was strongly associated with neurologic events (odds ratio [OR] 4.9, 95% CI 2.7-8.8, P < .001), as was prior CVA (OR 2.4, 95% CI 1.4-4.4, P = .002) and African American race (OR

  4. CADDIS Volume 4. Data Analysis: Advanced Analyses - Controlling for Natural Variability

    Science.gov (United States)

    Methods for controlling natural variability, predicting environmental conditions from biological observations method, biological trait data, species sensitivity distributions, propensity scores, Advanced Analyses of Data Analysis references.

  5. CADDIS Volume 4. Data Analysis: Advanced Analyses - Controlling for Natural Variability: SSD Plot Diagrams

    Science.gov (United States)

    Methods for controlling natural variability, predicting environmental conditions from biological observations method, biological trait data, species sensitivity distributions, propensity scores, Advanced Analyses of Data Analysis references.

  6. Variable Structure PID Control to Prevent Integrator Windup

    Science.gov (United States)

    Hall, C. E.; Hodel, A. S.; Hung, J. Y.

    1999-01-01

    PID controllers are frequently used to control systems requiring zero steady-state error while maintaining requirements for settling time and robustness (gain/phase margins). PID controllers suffer significant loss of performance due to short-term integrator wind-up when used in systems with actuator saturation. We examine several existing and proposed methods for the prevention of integrator wind-up in both continuous and discrete time implementations.

  7. A Correlational Study on Critical Thinking in Nursing as an Outcome Variable for Success

    Science.gov (United States)

    Porter, Rebecca Jean

    2018-01-01

    Critical thinking is a required curricular outcome for nursing education; however, the literature shows a gap related to valid and reliable tools to measure critical thinking specific to nursing and relating that critical thinking measurement to meaningful outcomes. This study examined critical thinking scores, as measured by Assessment…

  8. Design Method of Active Disturbance Rejection Variable Structure Control System

    Directory of Open Access Journals (Sweden)

    Yun-jie Wu

    2015-01-01

    Full Text Available Based on lines cluster approaching theory and inspired by the traditional exponent reaching law method, a new control method, lines cluster approaching mode control (LCAMC method, is designed to improve the parameter simplicity and structure optimization of the control system. The design guidelines and mathematical proofs are also given. To further improve the tracking performance and the inhibition of the white noise, connect the active disturbance rejection control (ADRC method with the LCAMC method and create the extended state observer based lines cluster approaching mode control (ESO-LCAMC method. Taking traditional servo control system as example, two control schemes are constructed and two kinds of comparison are carried out. Computer simulation results show that LCAMC method, having better tracking performance than the traditional sliding mode control (SMC system, makes the servo system track command signal quickly and accurately in spite of the persistent equivalent disturbances and ESO-LCAMC method further reduces the tracking error and filters the white noise added on the system states. Simulation results verify the robust property and comprehensive performance of control schemes.

  9. [Explore objective clinical variables for detecting delirium in ICU patients: a prospective case-control study].

    Science.gov (United States)

    Liu, Xiaojiang; Lyu, Jie; An, Youzhong

    2017-04-01

    The aim of this case-control study is to explore clinical objective variables for diagnosing delirium of intensive care unit (ICU) patients. According to the method of prospective case-control study, critical adult postoperative patients who were transferred to ICU of Peking University People's Hospital from October 2015 to May 2016 and needed mechanical ventilation were included. After evaluating the Richmond agitation sedation scale score (RASS), the patients whose score were -2 or greater were sorted into two groups, delirium and non-delirium, according to the confusion assessment method for the ICU (CAM-ICU). Then these patients were observed by domestic multifunctional detector for electroencephalographic (EEG) variables such as brain lateralization, brain introvert, brain activity, brain energy consumption, focus inward, focus outward, cerebral inhibition, fatigue, sleep severity, sedation index, pain index, anxiety index, fidgety index, stress index and the cerebral blood flow (CBF) index which was named of perfusion index. Other variables including indexes of ICU blood gas analysis, which was consisted of variables of blood gas analysis, routine blood test and biochemistry, previous history and prognostic outcome was recorded. Binary logistic regression was used for multivariate analysis. Forty-three postoperative patients, who needed intensive care, were included. Eighteen were in delirium group and twenty-five in control group. Excluding the trauma, variables like gender, age, temperature, heart rate, respiratory rate, mean arterial pressure, acute physiology and chronic health evaluationII(APACHEII) score, organ failure, dementia and emergency surgery didn't show any statistical significance between two groups. The trauma in delirious patients increased obviously compared with the control group (33.3% vs. 4.0%, P = 0.031). Except for the brain activity [122.47 (88.62, 154.21) vs. 89.40 (86.27, 115.97), P = 0.034], there were no statistical differences in

  10. LB01.06: VISIT-TO-VISIT BLOOD PRESSURE VARIABILITY AND CARDIOVASCULAR OUTCOMES IN FELODIPINE EVENT REDUCTION STUDY.

    Science.gov (United States)

    Zhang, Y; Zhang, X; Liu, L; Zanchetti, A

    2015-06-01

    Many antihypertensive outcome trials have shown that visit-to-visit blood pressure variability is correlated closely with clinical outcomes in hypertensive patients. The objective of the study was to investigate the relationship between visit-to-visit blood pressure variability (BPV) and the major cardiovascular outcomes in the Chinese hypertensive patients. Felodipine Event Reduction (FEVER) study was a double-blind, randomized trial on 9711 Chinese hypertensive patients, in whom cardiovascular outcomes were significantly reduced by more intense therapy achieving a mean of 138 mmHg SBP compared with less-intense therapy achieving a mean of 142 mmHg. Visit-to-visit BPV during the follow-up period [defined as standard deviation (SD), coefficient of variation (CV), and average real variability(ARV)] was derived from casual cuff BP measures after six months follow-up until the end of the study. Hazard ratios (HRs), for the incidence of CVD associated with SD, CV, and ARV of SBP and DBP were calculated using Cox proportional hazard models. Overall predictive power [area under receiver operating characteristic (AUC ROC) curve] of the level of blood pressure, blood pressure variability and other baseline characteristics was calculated. In FEVER study, visit-to-visit variability in SBP were significant predictors of subsequent stroke [eg, hazard ratios [HR] for ARV, SD and CV was 1.071 (95% CI: 1.025-1.118), 1.373 (95% CI: 1.159-1.626) and 0.572 (95% CI: 0.451-0,726)]. Visit-to-visit variability in DBP were also showed similar trend [eg, HR for ARV, SD and CV was 1.066 (95% CI: 0.992-1.145), 1.931 (95% CI: 1.435-2.598) and 0.558 (95% CI: 0.438-0,710)]. However, using the analysis of AUC ROC analysis, the risk importance sequence of the stroke events in this cohort was level of SBP, age, level of DBP ARV, SD, sex, CV and treatment. Visit-to-visit blood pressure variability has some effects on the cardiovascular outcomes in the Chinese hypertensive patents in the cohort in

  11. Power control in wireless sensor networks with variable interference

    NARCIS (Netherlands)

    Chincoli, M.; Syed, A.A.; Exarchakos, G.; Liotta, A.

    2016-01-01

    Adaptive transmission power control schemes have been introduced in wireless sensor networks to adjust energy consumption under different network conditions. This is a crucial goal, given the constraints under which sensor communications operate. Power reduction may however have counterproductive

  12. Variable Emissive Smart Radiator for Dynamic Thermal Control

    Data.gov (United States)

    National Aeronautics and Space Administration — Trending towards reduced power and mass budget on satellites with a longer mission life, there is a need for a reliable thermal control system that is more efficient...

  13. Bio-inspired online variable recruitment control of fluidic artificial muscles

    Science.gov (United States)

    Jenkins, Tyler E.; Chapman, Edward M.; Bryant, Matthew

    2016-12-01

    This paper details the creation of a hybrid variable recruitment control scheme for fluidic artificial muscle (FAM) actuators with an emphasis on maximizing system efficiency and switching control performance. Variable recruitment is the process of altering a system’s active number of actuators, allowing operation in distinct force regimes. Previously, FAM variable recruitment was only quantified with offline, manual valve switching; this study addresses the creation and characterization of novel, on-line FAM switching control algorithms. The bio-inspired algorithms are implemented in conjunction with a PID and model-based controller, and applied to a simulated plant model. Variable recruitment transition effects and chatter rejection are explored via a sensitivity analysis, allowing a system designer to weigh tradeoffs in actuator modeling, algorithm choice, and necessary hardware. Variable recruitment is further developed through simulation of a robotic arm tracking a variety of spline position inputs, requiring several levels of actuator recruitment. Switching controller performance is quantified and compared with baseline systems lacking variable recruitment. The work extends current variable recruitment knowledge by creating novel online variable recruitment control schemes, and exploring how online actuator recruitment affects system efficiency and control performance. Key topics associated with implementing a variable recruitment scheme, including the effects of modeling inaccuracies, hardware considerations, and switching transition concerns are also addressed.

  14. Patient-Therapist Identification in Relation to Both Patient and Therapist Variables and Therapy Outcome

    Science.gov (United States)

    Melnick, Barry

    1972-01-01

    The results of the study confirmed the hypothesis that greater patient identification with the therapist, as defined by increased similarity between the patient's and therapist's semantic differential ratings, moderately correlated with more successful therapy outcome. (Author)

  15. Reciprocal Interaction of 24-Hour Blood Pressure Variability and Systolic Blood Pressure on Outcome in Stroke Thrombolysis.

    Science.gov (United States)

    Kellert, Lars; Hametner, Christian; Ahmed, Niaz; Rauch, Geraldine; MacLeod, Mary J; Perini, Francesco; Lees, Kennedy R; Ringleb, Peter A

    2017-07-01

    Significance and management of blood pressure (BP) changes in acute stroke care are unclear. Here, we aimed to investigate the impact of 24-hour BP variability (BPV) on outcome in patients with acute ischemic stroke treated with intravenous thrombolysis. From the Safe Implementation of Treatment in Stroke International Stroke Thrombolysis registry, 28 976 patients with documented pre-treatment systolic BP at 2 and 24 hours were analyzed. The primary measure of BP variability was successive variability. Data were preprocessed using coarsened exact matching. We assessed early neurological improvement, symptomatic intracerebral hemorrhage (SICH), and long-term functional outcome (modified Rankin Scale [mRS] at 90 days) by binary and ordinal regression analyses. Attempts to explain successive variation for analysis of BPV with patients characteristics at admission found systolic BP (5.5% variance) to be most influential, yet 92% of BPV variance remained unexplained. Independently from systolic BP, successive variation for analysis of BPV was associated with poor functional outcome mRS score of 0 to 2 (odds ratio [OR], 0.94; 95% confidence interval [CI], 0.90-0.98), disadvantage across the shift of mRS (OR, 1.04; 95% CI, 1.01-1.08), mortality (OR, 1.10; 95% CI, 1.01-1.08), SICH SITS (OR, 1.14; 95% CI, 1.06-1.23), and SICH ECASS (OR, 1.24; 95% CI, 1.10-1.40; ECASS [European Cooperative Acute Stroke Study 2]). Analyzing successive variation for analysis of BPV as a function of pre-treatment, systolic BP significantly improved the prediction of functional outcome (mRS score of 0-1, mRS score of 0-2, neurological improvement, mRS-shift: all P interaction accounting for pre-treatment BP and the acute BP course (ie, BPV) to achieve best possible outcome for the patient. © 2017 American Heart Association, Inc.

  16. Global chaos synchronization of electro-mechanical gyrostat systems via variable substitution control

    International Nuclear Information System (INIS)

    Chen Yun; Wu Xiaofeng; Liu Zhong

    2009-01-01

    This paper studies global synchronization of non-autonomous chaotic electro-mechanical gyrostat systems via variable substitution control. A master-slave non-autonomous synchronization scheme with variable substitution control is mathematically presented. Based on the scheme, some sufficient algebraic criteria for global chaos synchronization of master and slave electro-mechanical gyrostat systems via various single-variable coupling are derived. The effectiveness of the obtained criteria is numerically illustrated by the examples.

  17. Techniques for controlling variability in gram staining of obligate anaerobes.

    Science.gov (United States)

    Johnson, M J; Thatcher, E; Cox, M E

    1995-01-01

    Identification of anaerobes recovered from clinical samples is complicated by the fact that certain gram-positive anaerobes routinely stain gram negative; Peptostreptococcus asaccharolyticus, Eubacterium plautii, Clostridium ramosum, Clostridium symbiosum, and Clostridium clostridiiforme are among the nonconformists with regard to conventional Gram-staining procedures. Accurate Gram staining of American Type Culture Collection strains of these anaerobic bacteria is possible by implementing fixing and staining techniques within a gloveless anaerobic chamber. Under anaerobic conditions, gram-positive staining occurred in all test organisms with "quick" fixing techniques with both absolute methanol and formalin. The results support the hypothesis that, when anaerobic bacteria are exposed to oxygen, a breakdown of the physical integrity of the cell wall occurs, introducing Gram stain variability in gram-positive anaerobes. PMID:7538512

  18. VACOSS - variable coding seal system for nuclear material control

    International Nuclear Information System (INIS)

    Kennepohl, K.; Stein, G.

    1977-12-01

    VACOSS - Variable Coding Seal System - is intended to seal: rooms and containers with nuclear material, nuclear instrumentation and equipment of the operator, instrumentation and equipment at the supervisory authority. It is easy to handle, reusable, transportable and consists of three components: 1. Seal. The light guide in fibre optics with infrared light emitter and receiver serves as lead. The statistical treatment of coded data given in the seal via adapter box guarantees an extremely high degree of access reliability. It is possible to store the data of two undue seal openings together with data concerning time and duration of the opening. 2. The adapter box can be used for input or input and output of data indicating the seal integrity. 3. The simulation programme is located in the computing center of the supervisory authority and permits to determine date and time of opening by decoding the seal memory data. (orig./WB) [de

  19. Modelling and Multi-Variable Control of Refrigeration Systems

    DEFF Research Database (Denmark)

    Larsen, Lars Finn Slot; Holm, J. R.

    2003-01-01

    In this paper a dynamic model of a 1:1 refrigeration system is presented. The main modelling effort has been concentrated on a lumped parameter model of a shell and tube condenser. The model has shown good resemblance with experimental data from a test rig, regarding as well the static as the dyn......In this paper a dynamic model of a 1:1 refrigeration system is presented. The main modelling effort has been concentrated on a lumped parameter model of a shell and tube condenser. The model has shown good resemblance with experimental data from a test rig, regarding as well the static...... as the dynamic behavior. Based on this model the effects of the cross couplings has been examined. The influence of the cross couplings on the achievable control performance has been investigated. A MIMO controller is designed and the performance is compared with the control performance achieved by using...

  20. Optimal multivariable control of a wind turbine with variable speed

    NARCIS (Netherlands)

    Steinbuch, M.

    1987-01-01

    The control system design for a 310 kW horizontal axis wind energy conversion system with a synchronous generator and DC link is investigated. Because the wind turbine system has multiple inputs (pitch angle, field vollage alld delay angle), and multiple outputs, (speed and power), and because the

  1. Control of variable speed wind turbine with doubly-fed induction generator

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, A.D.; Soerensen, P. [Risoe National Lab., Wind Energy Dept., Roskilde (Denmark); Iov, F.; Blaabjerg, F. [Aalborg Univ., Inst. of Energy Technology, Aalborg (Denmark)

    2004-07-01

    draIn this paper, a Control method suitable for a variable speed grid connected pitch-controlled wind turbine with doubly-fed induction generator (DFIG) is developed. The targets of the Control system are: 1) to Control the power drawn from the wind turbine in order to track the wind turbine optimum operation point 2) to limit the power in case of high wind speeds and 3) to Control the reactive power interchanged between the wind turbine generator and the grid. The considered configuration of DFIG is an induction generator with a wound rotor connected to the grid through a back-to-back power converter and a stator directly connected to the grid. The paper presents the overall Control system of the variable speed DFIG wind turbine, with focus on the Control strategies and algorithms applied at each hierarchical Control level of the wind turbine. There are two Control levels: a DFIG Control level and wind turbine Control level. The DFIG Control level contains a fast Control of the power converter and of the doubly-fed induction generator and it has as goal to Control the active and reactive power of the wind turbine independently. The wind turbine Control level supervises with Control signals both the DFIG Control level and the hydraulic pitch Control system of the wind turbine. The present Control method is designed for normal continuous operations. The variable speed/variable pitch wind turbine with doubly-fed induction generator is implemented in the dynamic power system simulation tool DIgSILENT, which makes possible to investigate the dynamic performance of gid-connected wind turbines as a part of realistic electrical grid models. Several significant simulation results are performed With the overall Control-implemented algorithm applied on a variable speed, variable pitch wind turbine model. (au)

  2. Supratentorial Ependymoma: Disease Control, Complications, and Functional Outcomes After Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Landau, Efrat [Department of Radiation Oncology, Sheba Medical Center, Ramat Gan (Israel); Boop, Frederick A. [Department of Neurosurgery, St Jude Children' s Research Hospital, Memphis, Tennessee (United States); Conklin, Heather M. [Department of Psychology, St Jude Children' s Research Hospital, Memphis, Tennessee (United States); Wu, Shengjie; Xiong, Xiaoping [Department of Biostatistics, St Jude Children' s Research Hospital, Memphis, Tennessee (United States); Merchant, Thomas E., E-mail: thomas.merchant@stjude.org [Division of Radiation Oncology, St Jude Children' s Research Hospital, Memphis, Tennessee (United States)

    2013-03-15

    Purpose: Ependymoma is less commonly found in the supratentorial brain and has known clinical and molecular features that are unique. Our single-institution series provides valuable information about disease control for supratentorial ependymoma and the complications of supratentorial irradiation in children. Methods and Materials: A total of 50 children with newly diagnosed supratentorial ependymoma were treated with adjuvant radiation therapy (RT); conformal methods were used in 36 after 1996. The median age at RT was 6.5 years (range, 1-18.9 years). The entire group was characterized according to sex (girls 27), race (white 43), extent of resection (gross-total 46), and tumor grade (anaplastic 28). The conformal RT group was prospectively evaluated for neurologic, endocrine, and cognitive effects. Results: With a median follow-up time of 9.1 years from the start of RT for survivors (range, 0.2-23.2 years), the 10-year progression-free and overall survival were 73% + 7% and 76% + 6%, respectively. None of the evaluated factors was prognostic for disease control. Local and distant failures were evenly divided among the 16 patients who experienced progression. Eleven patients died of disease, and 1 of central nervous system necrosis. Seizure disorders were present in 17 patients, and 4 were considered to be clinically disabled. Clinically significant cognitive effects were limited to children with difficult-to-control seizures. The average values for intelligence quotient and academic achievement (reading, spelling, and math) were within the range of normal through 10 years of follow-up. Central hypothyroidism was the most commonly treated endocrinopathy. Conclusion: RT may be administered with acceptable risks for complications in children with supratentorial ependymoma. These results suggest that outcomes for these children are improving and that complications may be limited by use of focal irradiation methods.

  3. Supratentorial Ependymoma: Disease Control, Complications, and Functional Outcomes After Irradiation

    International Nuclear Information System (INIS)

    Landau, Efrat; Boop, Frederick A.; Conklin, Heather M.; Wu, Shengjie; Xiong, Xiaoping; Merchant, Thomas E.

    2013-01-01

    Purpose: Ependymoma is less commonly found in the supratentorial brain and has known clinical and molecular features that are unique. Our single-institution series provides valuable information about disease control for supratentorial ependymoma and the complications of supratentorial irradiation in children. Methods and Materials: A total of 50 children with newly diagnosed supratentorial ependymoma were treated with adjuvant radiation therapy (RT); conformal methods were used in 36 after 1996. The median age at RT was 6.5 years (range, 1-18.9 years). The entire group was characterized according to sex (girls 27), race (white 43), extent of resection (gross-total 46), and tumor grade (anaplastic 28). The conformal RT group was prospectively evaluated for neurologic, endocrine, and cognitive effects. Results: With a median follow-up time of 9.1 years from the start of RT for survivors (range, 0.2-23.2 years), the 10-year progression-free and overall survival were 73% + 7% and 76% + 6%, respectively. None of the evaluated factors was prognostic for disease control. Local and distant failures were evenly divided among the 16 patients who experienced progression. Eleven patients died of disease, and 1 of central nervous system necrosis. Seizure disorders were present in 17 patients, and 4 were considered to be clinically disabled. Clinically significant cognitive effects were limited to children with difficult-to-control seizures. The average values for intelligence quotient and academic achievement (reading, spelling, and math) were within the range of normal through 10 years of follow-up. Central hypothyroidism was the most commonly treated endocrinopathy. Conclusion: RT may be administered with acceptable risks for complications in children with supratentorial ependymoma. These results suggest that outcomes for these children are improving and that complications may be limited by use of focal irradiation methods

  4. Case-Mix Variables and Predictors for Outcomes of Laparoscopic Hysterectomy: A Systematic Review.

    Science.gov (United States)

    Driessen, Sara R C; Sandberg, Evelien M; la Chapelle, Claire F; Twijnstra, Andries R H; Rhemrev, Johann P T; Jansen, Frank Willem

    2016-01-01

    The assessment of surgical quality is complex, and an adequate case-mix correction is missing in currently applied quality indicators. The purpose of this study is to give an overview of all studies mentioning statistically significant associations between patient characteristics and surgical outcomes for laparoscopic hysterectomy (LH). Additionally, we identified a set of potential case-mix characteristics for LH. This systematic review was conducted according to the Meta-Analysis of Observational Studies in Epidemiology guidelines. We searched PubMed and EMBASE from January 1, 2000 to August 1, 2015. All articles describing statistically significant associations between patient characteristics and adverse outcomes of LH for benign indications were included. Primary outcomes were blood loss, operative time, conversion, and complications. The methodologic quality of the included studies was assessed using the Newcastle-Ottawa Quality Assessment Scale. The included articles were summed per predictor and surgical outcome. Three sets of case-mix characteristics were determined, stratified by different levels of evidence. Eighty-five of 1549 identified studies were considered eligible. Uterine weight and body mass index (BMI) were the most mentioned predictors (described, respectively, 83 and 45 times) in high quality studies. For longer operative time and higher blood loss, uterine weight ≥ 250 to 300 g and ≥500 g and BMI ≥ 30 kg/m(2) dominated as predictors. Previous operations, adhesions, and higher age were also considered as predictors for longer operative time. For complications and conversions, the patient characteristics varied widely, and uterine weight, BMI, previous operations, adhesions, and age predominated. Studies of high methodologic quality indicated uterine weight and BMI as relevant case-mix characteristics for all surgical outcomes. For future development of quality indicators of LH and to compare surgical outcomes adequately, a case

  5. Identifying the independent effect of HbA1c variability on adverse health outcomes in patients with Type 2 diabetes.

    Science.gov (United States)

    Prentice, J C; Pizer, S D; Conlin, P R

    2016-12-01

    To characterize the relationship between HbA 1c variability and adverse health outcomes among US military veterans with Type 2 diabetes. This retrospective cohort study used Veterans Affairs and Medicare claims for veterans with Type 2 diabetes taking metformin who initiated a second diabetes medication (n = 50 861). The main exposure of interest was HbA 1c variability during a 3-year baseline period. HbA 1c variability, categorized into quartiles, was defined as standard deviation, coefficient of variation and adjusted standard deviation, which accounted for the number and mean number of days between HbA 1c tests. Cox proportional hazard models predicted mortality, hospitalization for ambulatory care-sensitive conditions, and myocardial infarction or stroke and were controlled for mean HbA 1c levels and the direction of change in HbA 1c levels during the baseline period. Over a mean 3.3 years of follow-up, all HbA 1c variability measures significantly predicted each outcome. Using the adjusted standard deviation measure for HbA 1c variability, the hazard ratios for the third and fourth quartile predicting mortality were 1.14 (95% CI 1.04, 1.25) and 1.42 (95% CI 1.28, 1.58), for myocardial infarction and stroke they were 1.25 (95% CI 1.10, 1.41) and 1.23 (95% CI 1.07, 1.42) and for ambulatory-care sensitive condition hospitalization they were 1.10 (95% CI 1.03, 1.18) and 1.11 (95% CI 1.03, 1.20). Higher baseline HbA 1c levels independently predicted the likelihood of each outcome. In veterans with Type 2 diabetes, greater HbA 1c variability was associated with an increased risk of adverse long-term outcomes, independently of HbA 1c levels and direction of change. Limiting HbA 1c fluctuations over time may reduce complications. © 2016 Diabetes UK.

  6. Adaptive pitch control for variable speed wind turbines

    Science.gov (United States)

    Johnson, Kathryn E [Boulder, CO; Fingersh, Lee Jay [Westminster, CO

    2012-05-08

    An adaptive method for adjusting blade pitch angle, and controllers implementing such a method, for achieving higher power coefficients. Average power coefficients are determined for first and second periods of operation for the wind turbine. When the average power coefficient for the second time period is larger than for the first, a pitch increment, which may be generated based on the power coefficients, is added (or the sign is retained) to the nominal pitch angle value for the wind turbine. When the average power coefficient for the second time period is less than for the first, the pitch increment is subtracted (or the sign is changed). A control signal is generated based on the adapted pitch angle value and sent to blade pitch actuators that act to change the pitch angle of the wind turbine to the new or modified pitch angle setting, and this process is iteratively performed.

  7. Effects of surgeon variability on oncologic and functional outcomes in a population-based setting.

    Science.gov (United States)

    Carlsson, Sigrid; Berglund, Anders; Sjoberg, Daniel; Khatami, Ali; Stranne, Johan; Bergdahl, Svante; Lodding, Pär; Aus, Gunnar; Vickers, Andrew; Hugosson, Jonas

    2014-03-06

    Oncologic and functional outcomes after radical prostatectomy (RP) can vary between surgeons to a greater extent than is expected by chance. We sought to examine the effects of surgeon variation on functional and oncologic outcomes for patients undergoing RP for prostate cancer in a European center. The study comprised 1,280 men who underwent open retropubic RP performed by one of nine surgeons at an academic institution in Sweden between 2001 and 2008. Potency and continence outcomes were measured preoperatively and 18 months postoperatively by patient-administered questionnaires. Biochemical recurrence (BCR) was defined as a prostate-specific antigen (PSA) value > 0.2 ng/mL with at least one confirmatory rise. Multivariable random effect models were used to evaluate heterogeneity between surgeons, adjusting for case mix (age, PSA, pathological stage and grade), year of surgery, and surgical experience. Of 679 men potent at baseline, 647 provided data at 18 months with 122 (19%) reporting potency. We found no evidence for heterogeneity of potency outcomes between surgeons (P = 1). The continence rate for patients at 18 months was 85%, with 836 of the 979 patients who provided data reporting continence. There was statistically significant heterogeneity between surgeons (P = 0.001). We did not find evidence of an association between surgeons' adjusted probabilities of functional recovery and 5-year probability of freedom from BCR. Our data support previous studies regarding a large heterogeneity among surgeons in continence outcomes for patients undergoing RP. This indicates that some patients are receiving sub-optimal care. Quality assurance measures involving performance feedback, should be considered. When surgeons are aware of their outcomes, they can improve them to provide better care to patients.

  8. Optimal Control of Thermo--Fluid Phenomena in Variable Domains

    Science.gov (United States)

    Volkov, Oleg; Protas, Bartosz

    2008-11-01

    This presentation concerns our continued research on adjoint--based optimization of viscous incompressible flows (the Navier--Stokes problem) coupled with heat conduction involving change of phase (the Stefan problem), and occurring in domains with variable boundaries. This problem is motivated by optimization of advanced welding techniques used in automotive manufacturing, where the goal is to determine an optimal heat input, so as to obtain a desired shape of the weld pool surface upon solidification. We argue that computation of sensitivities (gradients) in such free--boundary problems requires the use of the shape--differential calculus as a key ingredient. We also show that, with such tools available, the computational solution of the direct and inverse (optimization) problems can in fact be achieved in a similar manner and in a comparable computational time. Our presentation will address certain mathematical and computational aspects of the method. As an illustration we will consider the two--phase Stefan problem with contact point singularities where our approach allows us to obtain a thermodynamically consistent solution.

  9. Online optimal control of variable refrigerant flow and variable air volume combined air conditioning system for energy saving

    International Nuclear Information System (INIS)

    Zhu, Yonghua; Jin, Xinqiao; Du, Zhimin; Fang, Xing

    2015-01-01

    The variable refrigerant flow (VRF) and variable air volume (VAV) combined air conditioning system can solve the problem of the VRF system in outdoor air ventilation while taking advantage of its high part load energy efficiency. Energy performance of the combined air conditioning system can also be optimized by joint control of both the VRF and the VAV parts. A model-based online optimal control strategy for the combined air conditioning system is presented. Simplified adaptive models of major components of the combined air conditioning system are firstly developed for predicting system performances. And a cost function in terms of energy consumption and thermal comfort is constructed. Genetic algorithm is used to search for the optimal control sets. The optimal control strategy is tested and evaluated through two case studies based on the simulation platform. Results show that the optimal strategy can effectively reduce energy consumption of the combined air conditioning system while maintaining acceptable thermal comfort. - Highlights: • A VRF and VAV combined system is proposed. • A model-based online optimal control strategy is proposed for the combined system. • The strategy can reduce energy consumption without sacrificing thermal comfort. • Novel simplified adaptive models are firstly developed for the VRF system

  10. The influence of variable range of motion training on neuromuscular performance and control of external loads.

    Science.gov (United States)

    Clark, Ross A; Humphries, Brendan; Hohmann, Erik; Bryant, Adam L

    2011-03-01

    Resistance training programs that emphasize high force production in different regions of the range of motion (ROM) may provide performance benefits. This study examined whether variable ROM (VROM) training, which consists of partial ROM training with countermovements performed in a different phase of the ROM for each set, results in improved functional performance. Twenty-two athletes (age 22.7 ± 2.4 years, height 1.81 ± 0.07 m, and body mass 94.6 ± 14.5 kg) with extensive resistance training backgrounds performed either a VROM or full ROM control (CON) 5-week, concentric work-matched training program. The participants were assigned to a group based on stratified randomization incorporating their strength levels and performance gains in preceding training microcycles. Testing consisted of assessing the force-ROM relationship during isokinetic and isometric bench press and ballistic bench throws, with normalized electromyography amplitude assessed during the isometric tests. Repeated-measure analyses of variance revealed that the VROM intervention significantly (p force (+15.7%), in addition to isokinetic peak force in the terminal ROM (13.5% increase). No significant differences were observed in the CON group or between groups for any other outcome measures. Analysis of the force-ROM relationship revealed that that the VROM intervention enhanced performance at shorter muscle lengths. These findings suggest that VROM training improves terminal and midrange performance gains, resulting in the athlete possessing an improved ability to control external loading and produce dynamic force.

  11. Control strategy for energy-efficient bipedal walking with variable leg stiffness

    NARCIS (Netherlands)

    Visser, L.C.; Stramigioli, Stefano; Carloni, Raffaella

    In this work, we propose a hybrid model for a bipedal walker with controlled variable leg stiffness, and a control strategy for stable gait control. The control reference is a passive gait of the limit-case bipedal spring-loaded inverted pendulum model with massless feet, ensuring that the gait is

  12. Comparison of glycemic control and variability in patients with type 2 and posttransplantation diabetes mellitus.

    Science.gov (United States)

    Werzowa, Johannes; Pacini, Giovanni; Hecking, Manfred; Fidler, Catharina; Haidinger, Michael; Brath, Helmut; Thomas, Andreas; Säemann, Marcus D; Tura, Andrea

    2015-01-01

    Posttransplantation diabetes mellitus (PTDM) is a common complication after renal transplantation leading to increased cardiovascular morbidity and mortality. In subjects with type 2 diabetes (T2DM) increased glycemic variability and poor glycemic control have been associated with cardiovascular complications. We therefore aimed at determining glycemic variability and glycemic control in subjects with PTDM in comparison to T2DM subjects. In this observational study we analyzed 10 transplanted subjects without diabetes (Control), 10 transplanted subjects with PTDM, and 8 non-transplanted T2DM subjects using Continuous Glucose Monitoring (CGM). Several indices of glycemic control quality and variability were computed. Many indices of both glycemic control quality and variability were different between control and PTDM subjects, with worse values in PTDM. The indices of glycemic control, such as glucose mean, GRADE and M-value, were similar in PTDM and T2DM, but some indices of glycemic variability, that is CONGA, lability index and shape index, showed a markedly higher (i.e., worse) value in T2DM than in PTDM (P value range: 0.001-0.035). Although PTDM and T2DM subjects showed similar glycemic control quality, glycemic variability was significantly higher in T2DM. These data underscore potential important pathophysiological differences between T2DM and PTDM indicating that increased glycemic variability may not be a key factor for the excess cardiovascular mortality in patients with PTDM. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Variable Displacement Control of the Concrete Pumping System Based on Dynamic Programming

    Directory of Open Access Journals (Sweden)

    Ye Min

    2017-01-01

    Full Text Available To solve the problems of cylinder piston striking cylinder and the hydraulic shocking of the main pump, and causing energy waste problem, the method of variable displacement control of piston stroke was proposed. In order to achieve effective control of the piston stroke, variable displacement control model was established under the physical constraint condition of non-collision between piston and cylinder. And the control process was realized by Dynamic Programming(DP, the simulation and test results show that piston of concrete pumping system don’t strike cylinder and reduce the hydraulic shock of the main pump outlet, meanwhile improve the response speed of the cylinder and achieve energy-saving purposes under varying loads. This control model built in the integration design space of structure variable and control variable is of guiding significance for solving open-loop system’s engineering problems.

  14. Age at disease onset and peak ammonium level rather than interventional variables predict the neurological outcome in urea cycle disorders.

    Science.gov (United States)

    Posset, Roland; Garcia-Cazorla, Angeles; Valayannopoulos, Vassili; Teles, Elisa Leão; Dionisi-Vici, Carlo; Brassier, Anaïs; Burlina, Alberto B; Burgard, Peter; Cortès-Saladelafont, Elisenda; Dobbelaere, Dries; Couce, Maria L; Sykut-Cegielska, Jolanta; Häberle, Johannes; Lund, Allan M; Chakrapani, Anupam; Schiff, Manuel; Walter, John H; Zeman, Jiri; Vara, Roshni; Kölker, Stefan

    2016-09-01

    Patients with urea cycle disorders (UCDs) have an increased risk of neurological disease manifestation. Determining the effect of diagnostic and therapeutic interventions on the neurological outcome. Evaluation of baseline, regular follow-up and emergency visits of 456 UCD patients prospectively followed between 2011 and 2015 by the E-IMD patient registry. About two-thirds of UCD patients remained asymptomatic until age 12 days [i.e. the median age at diagnosis of patients identified by newborn screening (NBS)] suggesting a potential benefit of NBS. In fact, NBS lowered the age at diagnosis in patients with late onset of symptoms (>28 days), and a trend towards improved long-term neurological outcome was found for patients with argininosuccinate synthetase and lyase deficiency as well as argininemia identified by NBS. Three to 17 different drug combinations were used for maintenance therapy, but superiority of any single drug or specific drug combination above other combinations was not demonstrated. Importantly, non-interventional variables of disease severity, such as age at disease onset and peak ammonium level of the initial hyperammonemic crisis (cut-off level: 500 μmol/L) best predicted the neurological outcome. Promising results of NBS for late onset UCD patients are reported and should be re-evaluated in a larger and more advanced age group. However, non-interventional variables affect the neurological outcome of UCD patients. Available evidence-based guideline recommendations are currently heterogeneously implemented into practice, leading to a high variability of drug combinations that hamper our understanding of optimised long-term and emergency treatment.

  15. Semiparametric methods for estimation of a nonlinear exposure‐outcome relationship using instrumental variables with application to Mendelian randomization

    Science.gov (United States)

    Staley, James R.

    2017-01-01

    ABSTRACT Mendelian randomization, the use of genetic variants as instrumental variables (IV), can test for and estimate the causal effect of an exposure on an outcome. Most IV methods assume that the function relating the exposure to the expected value of the outcome (the exposure‐outcome relationship) is linear. However, in practice, this assumption may not hold. Indeed, often the primary question of interest is to assess the shape of this relationship. We present two novel IV methods for investigating the shape of the exposure‐outcome relationship: a fractional polynomial method and a piecewise linear method. We divide the population into strata using the exposure distribution, and estimate a causal effect, referred to as a localized average causal effect (LACE), in each stratum of population. The fractional polynomial method performs metaregression on these LACE estimates. The piecewise linear method estimates a continuous piecewise linear function, the gradient of which is the LACE estimate in each stratum. Both methods were demonstrated in a simulation study to estimate the true exposure‐outcome relationship well, particularly when the relationship was a fractional polynomial (for the fractional polynomial method) or was piecewise linear (for the piecewise linear method). The methods were used to investigate the shape of relationship of body mass index with systolic blood pressure and diastolic blood pressure. PMID:28317167

  16. Overall control strategy of variable speed doubly-fed induction generator wind turbine

    DEFF Research Database (Denmark)

    Hansen, A.D.; Iov, F.; Sørensen, Poul Ejnar

    2004-01-01

    The variable speed doubly-fed induction generator wind turbine is today the most widely used concept. The paper presents an overall control system of the variable speed DFIG wind turbine, with focus on the control strategies and algorithms applied at each hierarchical control level of the wind tu......-fed induction generator is implemented in the dynamic power system simulation tool DIgSILENT. Simulation results are performed and analyzed in different normal operating conditions....

  17. Influence of Flow Sequencing Attributed to Climate Change and Climate Variability on the Assessment of Water-dependent Ecosystem Outcomes

    Science.gov (United States)

    Wang, J.; Nathan, R.; Horne, A.

    2017-12-01

    Traditional approaches to characterize water-dependent ecosystem outcomes in response to flow have been based on time-averaged hydrological indicators, however there is increasing recognition for the need to characterize ecological processes that are highly dependent on the sequencing of flow conditions (i.e. floods and droughts). This study considers the representation of flow regimes when considering assessment of ecological outcomes, and in particular, the need to account for sequencing and variability of flow. We conducted two case studies - one in the largely unregulated Ovens River catchment and one in the highly regulated Murray River catchment (both located in south-eastern Australia) - to explore the importance of flow sequencing to the condition of a typical long-lived ecological asset in Australia, the River Red Gum forests. In the first, the Ovens River case study, the implications of representing climate change using different downscaling methods (annual scaling, monthly scaling, quantile mapping, and weather generator method) on the sequencing of flows and resulting ecological outcomes were considered. In the second, the Murray River catchment, sequencing within a historic drought period was considered by systematically making modest adjustments on an annual basis to the hydrological records. In both cases, the condition of River Red Gum forests was assessed using an ecological model that incorporates transitions between ecological conditions in response to sequences of required flow components. The results of both studies show the importance of considering how hydrological alterations are represented when assessing ecological outcomes. The Ovens case study showed that there is significant variation in the predicted ecological outcomes when different downscaling techniques are applied. Similarly, the analysis in the Murray case study showed that the drought as it historically occurred provided one of the best possible outcomes for River Red Gum

  18. Teachers' and Students' Work-Culture Variables Associated with Positive School Outcome.

    Science.gov (United States)

    Goldwater, Orna D.; Nutt, Roberta L.

    1999-01-01

    Investigates whether goodness of fit between teachers' and students' backgrounds is associated with subjective grading and objective achievement at school. One hundred one seventh graders and twenty of their teachers completed the Self-Report Family Inventory. Similarity between teachers' and students' work-culture variables was associated with…

  19. Critical Speed Control for a Fixed Blade Variable Speed Wind Turbine

    Directory of Open Access Journals (Sweden)

    Morgan Rossander

    2017-10-01

    Full Text Available A critical speed controller for avoiding a certain rotational speed is presented. The controller is useful for variable speed wind turbines with a natural frequency in the operating range. The controller has been simulated, implemented and tested on an open site 12 kW vertical axis wind turbine prototype. The controller is based on an adaptation of the optimum torque control. Two lookup tables and a simple state machine provide the control logic of the controller. The controller requires low computational resources, and no wind speed measurement is needed. The results suggest that the controller is a feasible method for critical speed control. The skipping behavior can be adjusted using only two parameters. While tested on a vertical axis wind turbine, it may be used on any variable speed turbine with the control of generator power.

  20. Variables predictive of outcome in patients with acute hypercapneic respiratory failure treated with noninvasive ventilation

    International Nuclear Information System (INIS)

    Salahuddin, N.; Irfan, M.; Khan, S.; Naeem, M.; Haque, A.S.

    2010-01-01

    To assess results with NIV in acute hypercapneic respiratory failure and to identify outcome predictors. This was a retrospective observational study on consecutive patients presenting with acute type II respiratory failure and meeting criteria for NIV use over a 5 year period. Patients presenting with haemodynamic instability, inability to protect their airway, malignant arrhythmias and recent oesophageal surgery were excluded. Univariate and Multivariate regression analysis was used to determine the impact on survival. A p value of 35 Meq/L (adjusted Odds ratio 0.9; 95% CI 0.83, 0.98, p < 0.015) identified those less at risk for intubation. NIV was found to be both safe and effective in the management of acute hypercapneic respiratory failure. Sepsis and serum HCO/sub 3/ at admission identified patients having poor outcomes (JPMA 60:13; 2010). (author)

  1. A Neural Network Controller for Variable-Speed Variable-Pitch Wind Energy Conversion Systems Using Generalized Minimum Entropy Criterion

    Directory of Open Access Journals (Sweden)

    Mifeng Ren

    2014-01-01

    Full Text Available This paper considers the neural network controller design problem for variable pitch wind energy conversion systems (WECS with non-Gaussian wind speed disturbances in the stochastic distribution control framework. The approach here is used to directly model the unknown control law based on a fixed neural network (the number of layers and nodes in a neural network is fixed without the need to construct a separate model for the WECS. In order to characterize the randomness of the WECS, a generalized minimum entropy criterion is established to train connection weights of the neural network. For the train purpose, both kernel density estimation method and sliding window technique are adopted to estimate the PDF of tracking error and entropies. Due to the unknown process dynamics, the gradient of the objective function in a gradient-descent-type algorithm is estimated using an incremental perturbation method. The proposed approach is illustrated on a simulated WECS with non-Gaussian wind speed.

  2. Creation and control of variably shaped plasmas in TCV

    International Nuclear Information System (INIS)

    Hofmann, F.; Lister, J.B.; Anton, M.

    1994-01-01

    During the first year of operation, the TCV tokamak has produced a large variety of plasma shapes and magnetic configurations, with 1.0≤B tor ≤1.46T, I p ≤800kA, k≤2.05, -0.7≤δ ≤0.7. A new shape control algorithm, based on a finite element reconstruction of the plasma current in real time, has been implemented. Vertical growth rates of 800 sec -1 , corresponding to a stability margin f=1.15, have been stabilized. Ohmic H-modes, with energy confinement times reaching 80ms, normalized beta (β tor aB/I p ) of 1.9 and τ E /ITER89-P of 2.4 have been obtained in single-null X-point deuterium discharges with the ion grad B drift towards the X-point. Limiter H-modes with maximum line averaged electron densities of 1.7x10 20 m -3 have been observed in D-shaped plasmas with 360kA≤I p ≤600kA. (Author)

  3. Distributed Variable Droop Curve Control Strategies in Smart Microgrid

    Directory of Open Access Journals (Sweden)

    Changhong Deng

    2017-12-01

    Full Text Available In micro grid (MG, active/reactive power sharing for all dis-patchable units is an important issue. To meet fluctuating loads’ active and reactive power demands, the units generally adopt primary P-f and Q-U droop control methods. However, at different state of charge (SOC values, the capability of Lead Acid Battery Bank (LABB based units to take loads varies in a large range; active power should not be shared according to the units P capacities in a constant ratio. Besides, influenced by the output and line impedance between units, reactive power is not able to be shared in proportion to the units Q capacities. Another problem, after MG power balance requirement is satisfied, frequency and voltage are deviating from their rated values thus power quality is reduced. This paper presents a new smart MG which is based on the multi agent system. To solve the problems mentioned above, P-f and Q-U droop curves are adjusted dynamically and autonomously in local agents. To improve the power quality, secondary restoration function is realized in a decentralized way, the computation tasks are assigned to local, the computation capability and communication reliability requirements for central PC are low, and operation reliability is high. Simulation results back the proposed methods.

  4. Variable solar control using thermotropic core/shell particles

    Energy Technology Data Exchange (ETDEWEB)

    Muehling, Olaf; Seeboth, Arno; Ruhmann, Ralf; Potechius, Elvira; Vetter, Renate [Fraunhofer Institute for Applied Polymer Research (IAP), Department of Chromogenic Polymers, Volmerstr. 7B, 12489 Berlin (Germany); Haeusler, Tobias [Brandenburg University of Technology (BTU Cottbus), Chair of Applied Physics/Thermophysics, Konrad-Zuse-Str. 1, 03046 Cottbus (Germany)

    2009-09-15

    Subject of our recent investigations is the utilization of a reversible thermotropic material for a self-regulating sun protection glazing that controls the solar energy input in order to avoid overheating. Based on the well-established UV curing technology for laminated glass a superior thermotropic material with tunable switching characteristics and of low material costs was developed. The polymer layer contains core/shell particles homogeneously dispersed in a UV-cured resin. The particle core in turn consists of an n-alkane mixture that is responsible for the temperature-induced clear/opaque switching. To obtain particles of well-defined size and with a narrow size distribution, the miniemulsion polymerization technique was used. The visible and solar optical properties (normal-normal, normal-hemispherical, and normal-diffuse transmittance) in the off (clear) and in the on state (opaque) were determined by UV/Vis/NIR spectroscopy. Samples containing particles of high median diameter (>800 nm) primarily scatter in the forward direction. However, with smaller particles (300-600 nm) a higher backscattering (reflection) efficiency was achieved. The largest difference in the normal-hemispherical transmittance could be found with a particle amount of 6% and a median scattering domain diameter of {proportional_to}380 nm. (author)

  5. Variability in Glycemic Control with Temperature Transitions during Therapeutic Hypothermia

    Directory of Open Access Journals (Sweden)

    Krystal K. Haase

    2017-01-01

    Full Text Available Purpose. Patients treated with therapeutic hypothermia (TH and continuous insulin may be at increased risk of hyperglycemia or hypoglycemia, particularly during temperature transitions. This study aimed to evaluate frequency of glucose excursions during each phase of TH and to characterize glycemic control patterns in relation to survival. Methods. Patients admitted to a tertiary care hospital for circulatory arrest and treated with both therapeutic hypothermia and protocol-based continuous insulin between January 2010 and June 2013 were included. Glucose measures, insulin, and temperatures were collected through 24 hours after rewarming. Results. 24 of 26 patients experienced glycemic excursions. Hyperglycemic excursions were more frequent during initiation versus remaining phases (36.3%, 4.3%, 2.5%, and 4.0%, p=0.002. Hypoglycemia occurred most often during rewarming (0%, 7.7%, 23.1%, and 3.8%, p=0.02. Patients who experienced hypoglycemia had higher insulin doses prior to rewarming (16.2 versus 2.1 units/hr, p=0.03. Glucose variation was highest during hypothermia and trended higher in nonsurvivors compared to survivors (13.38 versus 9.16, p=0.09. Frequency of excursions was also higher in nonsurvivors (32.3% versus 19.8%, p=0.045. Conclusions. Glycemic excursions are common and occur more often in nonsurvivors. Excursions differ by phase but risk of hypoglycemia is increased during rewarming.

  6. Overall control strategy of variable speed doubly-fed induction generator wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Anca D.; Soerensen, Poul [Risoe National Laboratory, Roskilde (Denmark). Wind Energy Dept.; Iov, Florin; Blaabjerg, Frede [Aalborg Univ. (Denmark). Inst. of Energy Technology

    2004-07-01

    The variable speed doubly-fed induction generator wind turbine is today the most widely used concept. The paper presents an overall control system of the variable speed DFIG wind turbine, with focus on the control strategies and algorithms applied at each hierarchical control level of the wind turbine. The present control method is designed for normal continuous operations. The strongest feature of the implemented control method is that it allows the turbine to operate with the optimum power efficiency over a wider range of wind speeds. The variable speed/variable pitch wind turbine with doubly-fed induction generator is implemented in the dynamic power system simulation tool DIgSILENT. Simulation results are performed and analyzed in different normal operating conditions.

  7. Transparency of Outcome Reporting and Trial Registration of Randomized Controlled Trials Published in the Journal of Consulting and Clinical Psychology.

    Directory of Open Access Journals (Sweden)

    Marleine Azar

    Full Text Available Confidence that randomized controlled trial (RCT results accurately reflect intervention effectiveness depends on proper trial conduct and the accuracy and completeness of published trial reports. The Journal of Consulting and Clinical Psychology (JCCP is the primary trials journal amongst American Psychological Association (APA journals. The objectives of this study were to review RCTs recently published in JCCP to evaluate (1 adequacy of primary outcome analysis definitions; (2 registration status; and, (3 among registered trials, adequacy of outcome registrations. Additionally, we compared results from JCCP to findings from a recent study of top psychosomatic and behavioral medicine journals.Eligible RCTs were published in JCCP in 2013-2014. For each RCT, two investigators independently extracted data on (1 adequacy of outcome analysis definitions in the published report, (2 whether the RCT was registered prior to enrolling patients, and (3 adequacy of outcome registration.Of 70 RCTs reviewed, 12 (17.1% adequately defined primary or secondary outcome analyses, whereas 58 (82.3% had multiple primary outcome analyses without statistical adjustment or undefined outcome analyses. There were 39 (55.7% registered trials. Only two trials registered prior to patient enrollment with a single primary outcome variable and time point of assessment. However, in one of the two trials, registered and published outcomes were discrepant. No studies were adequately registered as per Standard Protocol Items: Recommendation for Interventional Trials guidelines. Compared to psychosomatic and behavioral medicine journals, the proportion of published trials with adequate outcome analysis declarations was significantly lower in JCCP (17.1% versus 32.9%; p = 0.029. The proportion of registered trials in JCCP (55.7% was comparable to behavioral medicine journals (52.6%; p = 0.709.The quality of published outcome analysis definitions and trial registrations in JCCP is

  8. Transparency of Outcome Reporting and Trial Registration of Randomized Controlled Trials Published in the Journal of Consulting and Clinical Psychology.

    Science.gov (United States)

    Azar, Marleine; Riehm, Kira E; McKay, Dean; Thombs, Brett D

    2015-01-01

    Confidence that randomized controlled trial (RCT) results accurately reflect intervention effectiveness depends on proper trial conduct and the accuracy and completeness of published trial reports. The Journal of Consulting and Clinical Psychology (JCCP) is the primary trials journal amongst American Psychological Association (APA) journals. The objectives of this study were to review RCTs recently published in JCCP to evaluate (1) adequacy of primary outcome analysis definitions; (2) registration status; and, (3) among registered trials, adequacy of outcome registrations. Additionally, we compared results from JCCP to findings from a recent study of top psychosomatic and behavioral medicine journals. Eligible RCTs were published in JCCP in 2013-2014. For each RCT, two investigators independently extracted data on (1) adequacy of outcome analysis definitions in the published report, (2) whether the RCT was registered prior to enrolling patients, and (3) adequacy of outcome registration. Of 70 RCTs reviewed, 12 (17.1%) adequately defined primary or secondary outcome analyses, whereas 58 (82.3%) had multiple primary outcome analyses without statistical adjustment or undefined outcome analyses. There were 39 (55.7%) registered trials. Only two trials registered prior to patient enrollment with a single primary outcome variable and time point of assessment. However, in one of the two trials, registered and published outcomes were discrepant. No studies were adequately registered as per Standard Protocol Items: Recommendation for Interventional Trials guidelines. Compared to psychosomatic and behavioral medicine journals, the proportion of published trials with adequate outcome analysis declarations was significantly lower in JCCP (17.1% versus 32.9%; p = 0.029). The proportion of registered trials in JCCP (55.7%) was comparable to behavioral medicine journals (52.6%; p = 0.709). The quality of published outcome analysis definitions and trial registrations in JCCP is

  9. Alpha male replacements in nonhuman primates: Variability in processes, outcomes, and terminology.

    Science.gov (United States)

    Teichroeb, Julie A; Jack, Katharine M

    2017-07-01

    Alpha male replacements occur in all primates displaying a dominance hierarchy but the process can be extremely variable. Here, we review the primate literature to document differences in patterns of alpha male replacements, showing that group composition and dispersal patterns account for a large proportion of this variability. We also examine the consequences of alpha male replacements in terms of sexual selection theory, infanticide, and group compositions. Though alpha male replacements are often called takeovers in the literature, this term masks much of the variation that is present in these processes. We argue for more concise terminology and provide a list of terms that we suggest more accurately define these events. Finally, we introduce the papers in this special issue on alpha male replacements in the American Journal of Primatology and discuss areas where data are still lacking. © 2017 Wiley Periodicals, Inc.

  10. Variable sleep schedules and outcomes in children with psychopathological problems: preliminary observations

    Directory of Open Access Journals (Sweden)

    Spruyt K

    2012-02-01

    Full Text Available Karen Spruyt1, Danielle L Raubuck2, Katie Grogan2, David Gozal1, Mark A Stein21Department of Pediatrics and Comer Children’s Hospital, Pritzker School of Medicine, University of Chicago, Chicago, IL; 2Institute for Juvenile Research, Hyperactivity and Learning Problems Clinic, University of Illinois at Chicago, Chicago, ILBackground: Night-to-night variability in sleep of children with attention deficit hyperactivity disorder (ADHD may be a mediator of behavioral phenotype. We examined the potential association between alertness, sleep, and eating behaviors in children with ADHD and comorbid problems.Methods: Sleep was monitored by actigraphy for 7 days. Questionnaires were used to assess sleep complaints, habits and food patterns by parental report, and sleep complaints and sleepiness by child report.Results: The group comprised 18 children, including 15 boys, aged 9.4 ± 1.7 years, 88.9% Caucasian, who took one or multiple medications. Children slept on average for 6 hours and 58 minutes with a variability of 1 hour 3 minutes relative to the mean, and their sleepiness scores were highly variable from day to day. Most children had a normal body mass index (BMI. Sleepiness and BMI were associated with sleep schedules and food patterns, such that they accounted for 76% of variance, predominantly by the association of BMI with mean wake after sleep onset and by bedtime sleepiness, with wake after sleep onset variability. Similarly, 97% of variance was shared with eating behaviors, such as desserts and snacks, and fast food meals were associated with morning sleepiness.Conclusion: Disrupted sleep and sleepiness appears to favor unhealthy food patterns and may place children with ADHD at increased risk for obesity.Keywords: sleep, child, attention deficit hyperactivity disorder, actigraphy

  11. Longitudinal assessment of maternal parenting capacity variables and child adjustment outcomes in pediatric cancer.

    Science.gov (United States)

    Fedele, David A; Mullins, Larry L; Wolfe-Christensen, Cortney; Carpentier, Melissa Y

    2011-04-01

    This preliminary investigation aimed to longitudinally examine parenting capacity variables, namely parental overprotection, perceived child vulnerability, and parenting stress and their relation to child adjustment in mothers of children on treatment for cancer. As part of a larger study, biological mothers (N=22) completed measures of parental overprotection, perceived child vulnerability, parenting stress, and child adjustment at Time 1 and a follow-up time point. Analyses were conducted to determine whether (1) levels of parental overprotection, perceived child vulnerability, and parenting stress declined from Time 1 to follow-up and (2) if Time 1 parenting capacity variables were associated with child adjustment at follow-up. Results revealed that parental overprotection, perceived child vulnerability, and parenting stress declined from Time 1 to follow-up, and levels of parental overprotection, perceived child vulnerability, and parenting stress at Time 1 were significantly related to child adjustment at follow-up. Collectively, the preliminary findings of this study indicate that mothers of children with cancer evidence improved parenting capacity over time. Furthermore, it seems that Time 1 parenting capacity variables are significantly related to later child adjustment.

  12. Very-low-speed variable-structure control of sensorless induction machine drives without signal injection

    DEFF Research Database (Denmark)

    Lascu, Christian; Boldea, Ion; Blaabjerg, Frede

    2005-01-01

    A sensorless induction machine drive is presented, in which the principles of variable-structure control and direct torque control (DTC) are combined to ensure high-performance operation in the steady state and under transient conditions. The drive employs a new torque and flux controller......, the "linear and variable-structure control", which realizes accurate and robust control in a wide speed range. Conventional DTC transient merits are preserved, while the steady-state behavior is significantly improved. The full-order state observer is a sliding-mode one, which does not require the rotor speed...

  13. Tracer responses and control of vessels with variable flow and volume

    International Nuclear Information System (INIS)

    Niemi, A.J.

    1990-01-01

    Continuous flow vessels which are subject to variation of flow and volume are characterized by time-variable parameters. It is shown that their residence time distributions and weighting functions obtained by tracer testing are made invariant with regard to the integrated flow variables which are introduced. Under variable flow but constant volume, one such integrated variable is sufficient. Under variable volume, two different variables are suggested for the residence time distribution and weighting function, while the appropriate variable of the perfect mixer differs distinctly from that of vessels with a distinct velocity profile. It is shown through a number of example cases, that an agreement with their mathematical models is reached. The approach is extended to include also arbitrary, non-analytic response functions obtained by tracer measurements. Applications of the derived models and their incorporation in automatic control algorithms is discussed. (orig.) [de

  14. Power maximization of variable-speed variable-pitch wind turbines using passive adaptive neural fault tolerant control

    Science.gov (United States)

    Habibi, Hamed; Rahimi Nohooji, Hamed; Howard, Ian

    2017-09-01

    Power maximization has always been a practical consideration in wind turbines. The question of how to address optimal power capture, especially when the system dynamics are nonlinear and the actuators are subject to unknown faults, is significant. This paper studies the control methodology for variable-speed variable-pitch wind turbines including the effects of uncertain nonlinear dynamics, system fault uncertainties, and unknown external disturbances. The nonlinear model of the wind turbine is presented, and the problem of maximizing extracted energy is formulated by designing the optimal desired states. With the known system, a model-based nonlinear controller is designed; then, to handle uncertainties, the unknown nonlinearities of the wind turbine are estimated by utilizing radial basis function neural networks. The adaptive neural fault tolerant control is designed passively to be robust on model uncertainties, disturbances including wind speed and model noises, and completely unknown actuator faults including generator torque and pitch actuator torque. The Lyapunov direct method is employed to prove that the closed-loop system is uniformly bounded. Simulation studies are performed to verify the effectiveness of the proposed method.

  15. Synchronization of chaotic systems with parameter uncertainties via variable structure control

    International Nuclear Information System (INIS)

    Etemadi, Shahram; Alasty, Aria; Salarieh, Hassan

    2006-01-01

    The Letter introduces a robust control design method to synchronize a pair of different uncertain chaotic systems. The technique is based on sliding-mode and variable structure control theories. Comparison of proposed method with previous works is performed during simulations. It is shown that the proposed controller while appearing in a faster response, is able to overcome random uncertainties of all model parameters

  16. Synchronization of chaotic systems with parameter uncertainties via variable structure control

    Energy Technology Data Exchange (ETDEWEB)

    Etemadi, Shahram [Centre of Excellence in Design, Robotics and Automation (CEDRA), School of Mechanical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Alasty, Aria [Centre of Excellence in Design, Robotics and Automation (CEDRA), School of Mechanical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of)]. E-mail: aalasti@sharif.edu; Salarieh, Hassan [Centre of Excellence in Design, Robotics and Automation (CEDRA), School of Mechanical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2006-08-28

    The Letter introduces a robust control design method to synchronize a pair of different uncertain chaotic systems. The technique is based on sliding-mode and variable structure control theories. Comparison of proposed method with previous works is performed during simulations. It is shown that the proposed controller while appearing in a faster response, is able to overcome random uncertainties of all model parameters.

  17. A disturbance decoupling nonlinear control law for variable speed wind turbines

    DEFF Research Database (Denmark)

    Thomsen, Sven Creutz; Poulsen, Niels Kjølstad

    2007-01-01

    This paper describes a nonlinear control law for controlling variable speed wind turbines using feedback linearization. The novel aspect of the control law is its ability to decouple the effect of wind fluctuations. Furthermore, the transformation to feedback linearizable coordinates is chosen...

  18. Experimental analysis of fuzzy controlled energy efficient demand controlled ventilation economizer cycle variable air volume air conditioning system

    Directory of Open Access Journals (Sweden)

    Rajagopalan Parameshwaran

    2008-01-01

    Full Text Available In the quest for energy conservative building design, there is now a great opportunity for a flexible and sophisticated air conditioning system capable of addressing better thermal comfort, indoor air quality, and energy efficiency, that are strongly desired. The variable refrigerant volume air conditioning system provides considerable energy savings, cost effectiveness and reduced space requirements. Applications of intelligent control like fuzzy logic controller, especially adapted to variable air volume air conditioning systems, have drawn more interest in recent years than classical control systems. An experimental analysis was performed to investigate the inherent operational characteristics of the combined variable refrigerant volume and variable air volume air conditioning systems under fixed ventilation, demand controlled ventilation, and combined demand controlled ventilation and economizer cycle techniques for two seasonal conditions. The test results of the variable refrigerant volume and variable air volume air conditioning system for each techniques are presented. The test results infer that the system controlled by fuzzy logic methodology and operated under the CO2 based mechanical ventilation scheme, effectively yields 37% and 56% per day of average energy-saving in summer and winter conditions, respectively. Based on the experimental results, the fuzzy based combined system can be considered to be an alternative energy efficient air conditioning scheme, having significant energy-saving potential compared to the conventional constant air volume air conditioning system.

  19. Heart rate control with adrenergic blockade: Clinical outcomes in cardiovascular medicine

    Directory of Open Access Journals (Sweden)

    David Feldman

    2010-05-01

    Full Text Available David Feldman1, Terry S Elton2, Doron M Menachemi3, Randy K Wexler41Heart Failure/Transplant and VAD Programs, Minneapolis Heart Institute, Minneapolis, Minnesota, USA; 2Division of Pharmacology, College of Pharmacology, The Ohio State University, Columbus, Ohio, USA; 3Heart Failure Services, Edith Wolfson Medical Center, The Heart Institute, Sakler School of Medicine, Tel-Aviv University, Holon, Israel; 4Department of Clinical Family Medicine, The Ohio State University, Columbus, Ohio, USAAbstract: The sympathetic nervous system is involved in regulating various cardiovascular parameters including heart rate (HR and HR variability. Aberrant sympathetic nervous system expression may result in elevated HR or decreased HR variability, and both are independent risk factors for development of cardiovascular disease, including heart failure, myocardial infarction, and hypertension. Epidemiologic studies have established that impaired HR control is linked to increased cardiovascular morbidity and mortality. One successful way of decreasing HR and cardiovascular mortality has been by utilizing β-blockers, because their ability to alter cell signaling at the receptor level has been shown to mitigate the pathogenic effects of sympathetic nervous system hyperactivation. Numerous clinical studies have demonstrated that β-blocker-mediated HR control improvements are associated with decreased mortality in postinfarct and heart failure patients. Although improved HR control benefits have yet to be established in hypertension, both traditional and vasodilating β-blockers exert positive HR control effects in this patient population. However, differences exist between traditional and vasodilating β-blockers; the latter reduce peripheral vascular resistance and exert neutral or positive effects on important metabolic parameters. Clinical evidence suggests that attainment of HR control is an important treatment objective for patients with cardiovascular

  20. Applications of variable speed control for contending with recurrent highway congestion.

    Science.gov (United States)

    2014-07-01

    This research project developed vital operational guidelines for design of a variable speed limit (VSL) system and its integrated operations with ramp metering control in contending with recurrent highway congestion. The developed guidelines can serv...

  1. Analytical Model for LLC Resonant Converter With Variable Duty-Cycle Control

    DEFF Research Database (Denmark)

    Shen, Yanfeng; Wang, Huai; Blaabjerg, Frede

    2016-01-01

    are identified and discussed. The proposed model enables a better understanding of the operation characteristics and fast parameter design of the LLC converter, which otherwise cannot be achieved by the existing simulation based methods and numerical models. The results obtained from the proposed model......In LLC resonant converters, the variable duty-cycle control is usually combined with a variable frequency control to widen the gain range, improve the light-load efficiency, or suppress the inrush current during start-up. However, a proper analytical model for the variable duty-cycle controlled LLC...... converter is still not available due to the complexity of operation modes and the nonlinearity of steady-state equations. This paper makes the efforts to develop an analytical model for the LLC converter with variable duty-cycle control. All possible operation models and critical operation characteristics...

  2. Research on Open-Closed-Loop Iterative Learning Control with Variable Forgetting Factor of Mobile Robots

    Directory of Open Access Journals (Sweden)

    Hongbin Wang

    2016-01-01

    Full Text Available We propose an iterative learning control algorithm (ILC that is developed using a variable forgetting factor to control a mobile robot. The proposed algorithm can be categorized as an open-closed-loop iterative learning control, which produces control instructions by using both previous and current data. However, introducing a variable forgetting factor can weaken the former control output and its variance in the control law while strengthening the robustness of the iterative learning control. If it is applied to the mobile robot, this will reduce position errors in robot trajectory tracking control effectively. In this work, we show that the proposed algorithm guarantees tracking error bound convergence to a small neighborhood of the origin under the condition of state disturbances, output measurement noises, and fluctuation of system dynamics. By using simulation, we demonstrate that the controller is effective in realizing the prefect tracking.

  3. Differentiating Between Precursor and Control Variables When Analyzing Reasoned Action Theories

    OpenAIRE

    Hennessy, Michael; Bleakley, Amy; Fishbein, Martin; Brown, Larry; DiClemente, Ralph; Romer, Daniel; Valois, Robert; Vanable, Peter A.; Carey, Michael P.; Salazar, Laura

    2009-01-01

    This paper highlights the distinction between precursor and control variables in the context of reasoned action theory. Here the theory is combined with structural equation modeling to demonstrate how age and past sexual behavior should be situated in a reasoned action analysis. A two wave longitudinal survey sample of African-American adolescents is analyzed where the target behavior is having vaginal sex. Results differ when age and past behavior are used as control variables and when they ...

  4. Variable-structure approaches analysis, simulation, robust control and estimation of uncertain dynamic processes

    CERN Document Server

    Senkel, Luise

    2016-01-01

    This edited book aims at presenting current research activities in the field of robust variable-structure systems. The scope equally comprises highlighting novel methodological aspects as well as presenting the use of variable-structure techniques in industrial applications including their efficient implementation on hardware for real-time control. The target audience primarily comprises research experts in the field of control theory and nonlinear dynamics but the book may also be beneficial for graduate students.

  5. Hypothetical Outcome Plots Outperform Error Bars and Violin Plots for Inferences about Reliability of Variable Ordering.

    Science.gov (United States)

    Hullman, Jessica; Resnick, Paul; Adar, Eytan

    2015-01-01

    Many visual depictions of probability distributions, such as error bars, are difficult for users to accurately interpret. We present and study an alternative representation, Hypothetical Outcome Plots (HOPs), that animates a finite set of individual draws. In contrast to the statistical background required to interpret many static representations of distributions, HOPs require relatively little background knowledge to interpret. Instead, HOPs enables viewers to infer properties of the distribution using mental processes like counting and integration. We conducted an experiment comparing HOPs to error bars and violin plots. With HOPs, people made much more accurate judgments about plots of two and three quantities. Accuracy was similar with all three representations for most questions about distributions of a single quantity.

  6. Hypothetical Outcome Plots Outperform Error Bars and Violin Plots for Inferences about Reliability of Variable Ordering.

    Directory of Open Access Journals (Sweden)

    Jessica Hullman

    Full Text Available Many visual depictions of probability distributions, such as error bars, are difficult for users to accurately interpret. We present and study an alternative representation, Hypothetical Outcome Plots (HOPs, that animates a finite set of individual draws. In contrast to the statistical background required to interpret many static representations of distributions, HOPs require relatively little background knowledge to interpret. Instead, HOPs enables viewers to infer properties of the distribution using mental processes like counting and integration. We conducted an experiment comparing HOPs to error bars and violin plots. With HOPs, people made much more accurate judgments about plots of two and three quantities. Accuracy was similar with all three representations for most questions about distributions of a single quantity.

  7. Validation of a new control system for Elekta accelerators facilitating continuously variable dose rate

    DEFF Research Database (Denmark)

    Bertelsen, Anders; Lorenzen, Ebbe L; Brink, Carsten

    2011-01-01

    ) as well as BVDR. Using CVDR opposed to BVDR for VMAT has the potential of reducing the treatment time but may lead to lower dosimetric accuracy due to faster moving accelerator parts. Using D7 and a test version of Integrity, differences in ability to control the accelerator, treatment efficiency......Elekta accelerators controlled by the current clinically used accelerator control system, Desktop 7.01 (D7), uses binned variable dose rate (BVDR) for volumetric modulated arc therapy (VMAT). The next version of the treatment control system (Integrity) supports continuously variable dose rate (CVDR...

  8. Model Predictive Control of a Nonlinear System with Known Scheduling Variable

    DEFF Research Database (Denmark)

    Mirzaei, Mahmood; Poulsen, Niels Kjølstad; Niemann, Hans Henrik

    2012-01-01

    Model predictive control (MPC) of a class of nonlinear systems is considered in this paper. We will use Linear Parameter Varying (LPV) model of the nonlinear system. By taking the advantage of having future values of the scheduling variable, we will simplify state prediction. Consequently...... the control problem of the nonlinear system is simplied into a quadratic programming. Wind turbine is chosen as the case study and we choose wind speed as the scheduling variable. Wind speed is measurable ahead of the turbine, therefore the scheduling variable is known for the entire prediction horizon....

  9. Penalized regression procedures for variable selection in the potential outcomes framework.

    Science.gov (United States)

    Ghosh, Debashis; Zhu, Yeying; Coffman, Donna L

    2015-05-10

    A recent topic of much interest in causal inference is model selection. In this article, we describe a framework in which to consider penalized regression approaches to variable selection for causal effects. The framework leads to a simple 'impute, then select' class of procedures that is agnostic to the type of imputation algorithm as well as penalized regression used. It also clarifies how model selection involves a multivariate regression model for causal inference problems and that these methods can be applied for identifying subgroups in which treatment effects are homogeneous. Analogies and links with the literature on machine learning methods, missing data, and imputation are drawn. A difference least absolute shrinkage and selection operator algorithm is defined, along with its multiple imputation analogs. The procedures are illustrated using a well-known right-heart catheterization dataset. Copyright © 2015 John Wiley & Sons, Ltd.

  10. Survivorship care plans: are randomized controlled trials assessing outcomes that are relevant to stakeholders?

    Science.gov (United States)

    Birken, Sarah A; Urquhart, Robin; Munoz-Plaza, Corrine; Zizzi, Alexandra R; Haines, Emily; Stover, Angela; Mayer, Deborah K; Hahn, Erin E

    2018-03-23

    The purpose of this study was to compare outcomes assessed in extant randomized controlled trials (RCTs) to outcomes that stakeholders expect from survivorship care plans (SCPs). To facilitate the transition from active treatment to follow-up care for the 15.5 million US cancer survivors, many organizations require SCP use. However, results of several RCTs of SCPs' effectiveness have been null, possibly because they have evaluated outcomes on which SCPs should be expected to have limited influence. Stakeholders (e.g., survivors, oncologists) may expect outcomes that differ from RCTs' outcomes. We identified RCTs' outcomes using a PubMed literature review. We identified outcomes that stakeholders expect from SCPs using semistructured interviews with stakeholders in three healthcare systems in the USA and Canada. Finally, we mapped RCTs' outcomes onto stakeholder-identified outcomes. RCT outcomes did not fully address outcomes that stakeholders expected from SCPs, and RCTs assessed outcomes that stakeholders did not expect from SCPs. RCTs often assessed outcomes only from survivors' perspectives. RCTs of SCPs' effectiveness have not assessed outcomes that stakeholders expect. To better understand SCPs' effectiveness, future RCTs should assess outcomes of SCP use that are relevant from the perspective of multiple stakeholders. SCPs' effectiveness may be optimized when used with an eye toward outcomes that stakeholders expect from SCPs. For survivors, this means using SCPs as a map to guide them with respect to what kind of follow-up care they should seek, when they should seek it, and from whom they should seek it.

  11. Relapse May Serve as a Mediator Variable in Longitudinal Outcomes in Multiple Sclerosis.

    Science.gov (United States)

    Stone, Lael Anne; Cutter, Gary Raymond; Fisher, Elizabeth; Richert, Nancy; McCartin, Jennifer; Ohayon, Joan; Bash, Craig; McFarland, Henry

    2016-05-01

    Contrast-enhancing lesions (CEL) on magnetic resonance imaging (MRI) are believed to represent inflammatory disease activity in multiple sclerosis (MS), but their relationship to subsequent long-term disability and progression is unclear, particularly at longer time periods such as 8-10 years. Between 1989 and 1994, 111 MS patients were seen at the National Institutes of Health for clinical evaluations and 3 monthly contrast-enhanced MRI scans. Of these, 94 patients were re-evaluated a mean of 8 years later (range 6.1-10.5 years) with a single MRI scan and clinical evaluation. CEL number and volume were determined at baseline and follow-up. The number of relapses was ascertained over the follow-up period and annualized relapse rates were calculated. Other MRI parameters, such as T2 hyperintensity volume, T1 volume, and brain parenchymal fraction, were also calculated. While there was no direct correlation between CEL number or volume at baseline and disability status at follow-up, CEL measures at baseline did correlate with number of relapses observed in the subsequent years, and the number of relapses in turn correlated with subsequent disability as well as transition to progressive MS. While number and volume of CEL at baseline do not directly correlate with disability in the longer term in MS, our data suggest that 1 route to disability involves relapses as a mediator variable in the causal sequence of MS progression from CEL to disability. Further studies using relapse as a mediator variable in a larger data set may be warranted. Copyright © 2015 by the American Society of Neuroimaging.

  12. Method of nuclear reactor control using a variable temperature load dependent set point

    International Nuclear Information System (INIS)

    Kelly, J.J.; Rambo, G.E.

    1982-01-01

    A method and apparatus for controlling a nuclear reactor in response to a variable average reactor coolant temperature set point is disclosed. The set point is dependent upon percent of full power load demand. A manually-actuated ''droop mode'' of control is provided whereby the reactor coolant temperature is allowed to drop below the set point temperature a predetermined amount wherein the control is switched from reactor control rods exclusively to feedwater flow

  13. Differentiating between precursor and control variables when analyzing reasoned action theories.

    Science.gov (United States)

    Hennessy, Michael; Bleakley, Amy; Fishbein, Martin; Brown, Larry; Diclemente, Ralph; Romer, Daniel; Valois, Robert; Vanable, Peter A; Carey, Michael P; Salazar, Laura

    2010-02-01

    This paper highlights the distinction between precursor and control variables in the context of reasoned action theory. Here the theory is combined with structural equation modeling to demonstrate how age and past sexual behavior should be situated in a reasoned action analysis. A two wave longitudinal survey sample of African-American adolescents is analyzed where the target behavior is having vaginal sex. Results differ when age and past behavior are used as control variables and when they are correctly used as precursors. Because control variables do not appear in any form of reasoned action theory, this approach to including background variables is not correct when analyzing data sets based on the theoretical axioms of the Theory of Reasoned Action, the Theory of Planned Behavior, or the Integrative Model.

  14. Nonlinear model-based robust control of a nuclear reactor using adaptive PIF gains and variable structure controller

    International Nuclear Information System (INIS)

    Park, Moon Ghu; Cho, Nam Zin

    1993-01-01

    A Nonlinear model-based Hybrid Controller (NHC) is developed which consists of the adaptive proportional-integral-feedforward (PIF) gains and variable structure controller. The controller has the robustness against modeling uncertainty and is applied to the trajectory tracking control of single-input, single-output nonlinear systems. The essence of the scheme is to divide the control into four different terms. Namely, the adaptive P-I-F gains and variable structure controller are used to accomplish the specific control actions by each terms. The robustness of the controller is guaranteed by the feedback of estimated uncertainty and the performance specification given by the adaptation of PIF gains using the second method of Lyapunov. The variable structure controller is incorporated to regulate the initial peak of the tracking error during the parameter adaptation is not settled yet. The newly developed NHC method is applied to the power tracking control of a nuclear reactor and the simulation results show great improvement in tracking performance compared with the conventional model-based control methods. (Author)

  15. Effectiveness of Splanchnic Nerve Neurolysis for Targeting Location of Cancer Pain: Using the Pain Drawing as an Outcome Variable.

    Science.gov (United States)

    Novy, Diane M; Engle, Mitchell P; Lai, Emily A; Cook, Christina; Martin, Emily C; Trahan, Lisa; Yu, Jun; Koyyalagunta, Dhanalakshmi

    2016-07-01

    The effectiveness of splanchnic nerve neurolysis (SNN) for cancer-related abdominal pain has been investigated using numeric pain intensity rating as an outcome variable. The outcome variable in this study used the grid method for obtaining a targeted pain drawing score on 60 patients with pain from pancreatic or gastro-intestinal primary cancers or metastatic disease to the abdominal region. Results demonstrate excellent inter-rater agreement (intra-class correlation [ICC] coefficient at pre-SNN = 0.97 and ICC at within one month post-SNN = 0.98) for the grid method of scoring the pain drawing and demonstrate psychometric generalizability among patients with cancer-related pain. Using the Wilcoxon signed rank test and associated effect sizes, results show significant improvement in dispersion of pain following SNN. Effect sizes for the difference in pre-SNN to 2 post-SNN time points were higher for the pain drawing than for pain intensity rating. Specifically, the effect size difference from pre- to within one month post-SNN was r = 0.42 for pain drawing versus r = 0.23 for pain intensity rating. Based on a smaller subset of patients who were seen within 1 - 6 months following SNN, the effect size difference from pre-SNN was r = 0.46 for pain drawing versus r = 0.00 for pain intensity rating. Collectively, these data support the use of the pain drawing as a reliable outcome measure among patients with cancer pain for procedures such as SNN that target specific location and dispersion of pain.

  16. Tongue motion variability with changes of upper airway stimulation electrode configuration and effects on treatment outcomes.

    Science.gov (United States)

    Steffen, Armin; Kilic, Ayse; König, Inke R; Suurna, Maria V; Hofauer, Benedikt; Heiser, Clemens

    2017-12-27

    Upper airway stimulation (UAS) is an effective treatment for obstructive sleep apnea (OSA). Previous data have demonstrated a correlation between the phenotype of tongue motion and therapy response. Closed loop hypoglossal nerve stimulation implant offers five different electrode configuration settings which may result in different tongue motion. Two-center, prospective consecutive trial in a university hospital setting. Clinical outcomes of 35 patients were analyzed after at least 12 months of device use. Tongue motion was assessed at various electrode configuration settings. Correlation between the tongue motion and treatment response was evaluated. OSA severity was significantly reduced with the use of UAS therapy (P < .001). Changes in tongue motion patterns were frequently observed (58.8%) with different electrode configuration settings. Most of the patients alternated between right and bilateral protrusion (73.5%), which are considered to be the optimal phenotypes for selective UAS responses. Different voltage settings were required to achieve functional stimulation levels when changing between the electrode settings. UAS is highly effective for OSA treatment in selected patients with an apnea-hypopnea index between 15 and 65 events per hour and higher body mass index. Attention should be given to patients with shifting tongue movement in response to change of electrode configuration. The intraoperative cuff placement should be reassessed when tongue movement shifting is observed. 4 Laryngoscope, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

  17. Visit-to-Visit Variability in Blood Pressure and Kidney and Cardiovascular Outcomes in Patients With Type 2 Diabetes and Nephropathy

    DEFF Research Database (Denmark)

    McMullan, Ciaran J; Lambers Heerspink, Hiddo J; Parving, Hans-Henrik

    2014-01-01

    -to-visit variability was calculated from the SD of the systolic blood pressure from 4 visits occurring 3-12 months postrandomization. OUTCOMES: The kidney disease outcome was defined as time to confirmed doubling of serum creatinine level, end-stage renal disease, or death; the cardiovascular outcome was defined......BACKGROUND: Increased systolic blood pressure variability between outpatient visits is associated with increased incidence of cardiovascular end points. However, few studies have examined the association of visit-to-visit variability in systolic blood pressure with clinically relevant kidney...... disease outcomes. We analyzed the association of systolic blood pressure visit-to-visit variability with renal and cardiovascular morbidity and mortality among individuals with diabetes and nephropathy. STUDY DESIGN: Observational analysis of IDNT (Irbesartan Diabetic Nephropathy Trial) and the RENAAL...

  18. Social variables affecting mate preferences, copulation and reproductive outcome in a pack of free-ranging dogs.

    Directory of Open Access Journals (Sweden)

    Simona Cafazzo

    Full Text Available Mating and reproductive outcome is often determined by the simultaneous operation of different mechanisms like intra-sexual competition, mating preferences and sexual coercion. The present study investigated how social variables affected mating outcome in a pack of free-ranging dogs, a species supposed to have lost most features of the social system of wolves during domestication. We found that, although the pack comprised multiple breeding individuals, both male copulation success and female reproductive success were positively influenced by a linear combination of dominance rank, age and leadership. Our results also suggest that mate preferences affect mating outcome by reinforcing the success of most dominant individuals. In particular, during their oestrous period bitches clearly searched for the proximity of high-ranking males who displayed affiliative behaviour towards them, while they were more likely to reject the males who intimidated them. At the same time, male courting effort and male-male competition for receptive females appeared to be stronger in the presence of higher-ranking females, suggesting a male preference for dominant females. To our knowledge, these results provide the first clear evidence of social regulation of reproductive activities in domestic dogs, and suggest that some common organizing mechanisms may contribute to shape the social organization of both dogs and wolves.

  19. Hemodynamic variables predict outcome of emergency thoracotomy in the pediatric trauma population.

    Science.gov (United States)

    Wyrick, Deidre L; Dassinger, Melvin S; Bozeman, Andrew P; Porter, Austin; Maxson, R Todd

    2014-09-01

    Limited data exist regarding indications for resuscitative emergency thoracotomy (ETR) in the pediatric population. We attempt to define the presenting hemodynamic parameters that predict survival for pediatric patients undergoing ETR. We reviewed all pediatric patients (age <18years), entered into the National Trauma Data Bank from 2007 to 2010, who underwent ETR within one hour of ED arrival. Mechanism of injury and hemodynamics were analyzed using Chi squared and Wilcoxon tests. 316 children (70 blunt, 240 penetrating) underwent ETR, 31% (98/316) survived to discharge. Less than 5% of patients survived when presenting SBP was ≤50mmHg or heart rate was ≤70bpm. For blunt injuries there were no survivors with a pulse ≤80bpm or SBP ≤60mmHg. When survivors were compared to nonsurvivors, blood pressure, pulse, and injury type were statistically significant when treated as independent variables and in a logistic regression model. When ETR was performed for SBP ≤50mmHg or for heart rate ≤70bpm less than 5% of patients survived. There were no survivors of blunt trauma when SBP was ≤60mmHg or pulse was ≤80bpm. This review suggests that ETR may have limited benefit in these patients. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. What is the value of the routine use of patient-reported outcome measures toward improvement of patient outcomes, processes of care, and health service outcomes in cancer care? A systematic review of controlled trials.

    Science.gov (United States)

    Kotronoulas, Grigorios; Kearney, Nora; Maguire, Roma; Harrow, Alison; Di Domenico, David; Croy, Suzanne; MacGillivray, Stephen

    2014-05-10

    The systematic use of patient-reported outcome measures (PROMs) has been advocated as an effective way to standardize cancer practice. Yet, the question of whether PROMs can lead to actual improvements in the quality of patient care remains under debate. This review examined whether inclusion of PROM in routine clinical practice is associated with improvements in patient outcomes, processes of care, and health service outcomes during active anticancer treatment. A systematic review of five electronic databases (Medline, EMBASE, CINAHL [Cumulative Index to Nursing and Allied Health Literature], PsycINFO, and Psychology and Behavioral Sciences Collection [PBSC]) was conducted from database inception to May 2012 to locate randomized and nonrandomized controlled trials of patients receiving active anticancer treatment or supportive care irrespective of type of cancer. Based on prespecified eligibility criteria, we included 26 articles that reported on 24 unique controlled trials. Wide variability in the design and use of interventions delivered, outcomes evaluated, and cancer- and modality-specific context was apparent. Health service outcomes were only scarcely included as end points. Overall, the number of statistically significant findings were limited and PROMs' intervention effect sizes were predominantly small-to-moderate. The routine use of PROMs increases the frequency of discussion of patient outcomes during consultations. In some studies, PROMs are associated with improved symptom control, increased supportive care measures, and patient satisfaction. Additional effort is required to ensure patient adherence, as well as additional support to clinicians who will respond to patient concerns and issues, with clear system guidelines in place to guide their responses. More research is required to support PROM cost-benefit in terms of patient safety, clinician burden, and health services usage.

  1. Variable gene dispersal conditions and spatial deforestation patterns can interact to affect tropical tree conservation outcomes.

    Directory of Open Access Journals (Sweden)

    Yamini Kashimshetty

    dispersal regimens will be a likely outcome of fragmentation. Conservation implications include possible manual interventions (manual manipulations of offspring dispersers and/or pollinators in forest fragments to increase population recovery and genetic diversity retention.

  2. Variable gene dispersal conditions and spatial deforestation patterns can interact to affect tropical tree conservation outcomes.

    Science.gov (United States)

    Kashimshetty, Yamini; Pelikan, Stephan; Rogstad, Steven H

    2015-01-01

    regimens will be a likely outcome of fragmentation. Conservation implications include possible manual interventions (manual manipulations of offspring dispersers and/or pollinators) in forest fragments to increase population recovery and genetic diversity retention.

  3. Cerebral venous thrombosis in Saudi Arabia. Clinical variables, response to treatment, and outcome

    International Nuclear Information System (INIS)

    Kajtazi, Naim I; Arulneyam, Jayanthi C; AlSenani, Fahmi M; Zimmerman, Valerie A; AlShami, Sadiq Y

    2009-01-01

    To investigate cerebral venous thrombosis (CVTR) clinical presentations, risk factors, and response to treatment in Saudi Arabia. Retrospective analysis of the King Farad Medical City, Riyadh, acute stroke database from April 2005 through February 2008 revealed 22 patients with CVTR. Hyper coagulable work-up and neuroimaging were performed. Sixteen patients were female (72.7%), and the median age was 35 years. Clinical presentations included: headache (77.3%), seizures (54.5%), focal neurological signs (54.5%), and decreased level of consciousness (50%). Over two-thirds (n=11; 69%) of female patients had a history of oral contraceptive use, which was the most common risk factor. Protein S deficiency (n=3), anti phospholipid antibody syndrome secondary to systemic lupus erythematosus (SLE) (n=1), rhinocerebral mucormycosis (n=1), leukemia (n=1), non-Hodgkin's lymphoma (n=1), sepsis (n=1), and unknown (n=6) were causes. Affected areas included superior sagittal (n=13), transverse (n=16), sigmoid (n=14), straight (n=6), and cavernous sinus (n=1); internal cerebral vein (n=2); vein of Galen (n=3); cortical veins (n=10); and internal jugular vein (n=12). Two patients had quadriparesis, and 2 patients died. The remainder (n=18, 81.8%) improved. Bilateral hemorrhagic presentation or venous infarction, deep venous system thrombosis, and underlying malignancy had less favorable results. Presentations in our series were similar to those in other reports, although altered consciousness and seizures were more common. Cortical vein involvement was also higher than commonly reported. Oral contraceptive use was a primary risk factor in female patients. Outcomes were favorable in 81.8% of patients. (author)

  4. Cutting-in control of the variable speed constant frequency wind power generator based on internal model controller

    Energy Technology Data Exchange (ETDEWEB)

    Guo Jindong; Xu Honghua; Zhao Dongli [Inst. of Electrical Engineering, CAS, BJ (China)

    2008-07-01

    The no-impact-current cutting-in-network control is the key of variable speed constant frequency (VSCF) wind power control system. Based on the stator flux linkage oriented control theory of doubly fed induction generator (DFIG), the field-oriented vector control technique and the internal model controller (IMC) are transplanted into the voltage control of DFIG and a novel cutting-in control strategy is obtained. The strategy does not need the exact inductor generator model, and has perfect performance without overshoot. The structure of the controller is simple, and the only parameter to be adjusted is directly related to system performance, so the strategy is easy to realize. Finally the strategy is studied by simulation using Matlab, the results of the simulation show that the control strategy can effectively control the stator voltage. (orig.)

  5. Linking implementation process to intervention outcomes in a middle school obesity prevention curriculum, ‘Choice, Control and Change’

    Science.gov (United States)

    Gray, Heewon Lee; Contento, Isobel R.; Koch, Pamela A.

    2015-01-01

    This study investigates the link between process evaluation components and the outcomes of a school-based nutrition curriculum intervention, ‘Choice, Control and Change’. Ten New York City public middle schools were recruited and randomly assigned into intervention or control condition. The curriculum was to improve sixth to seventh grade students’ energy balance related behaviors, based on social cognitive and self-determination theories, and implemented during the 2006–2007 school year (n = 1136). Behaviors and psychosocial variables were measured by self-reported questionnaires. Process components were evaluated with classroom observations, teacher interviews, and a student questionnaire. Using ‘Teacher Implementation’ (dose delivered) and ‘Student Reception’ (dose received) process data; intervention group was further categorized into medium- and high-implementation groups. Analysis of covariance revealed that, compared with control group, only high-implementation group showed significant improvement in students’ behavior and psychosocial outcomes. Hierarchical linear models showed that ‘Teacher Implementation’ and ‘Student Reception’ significantly predicted students’ sweetened beverage outcomes (P < 0.05). ‘Student Satisfaction’ was also greater when these implementation components were higher, and significantly associated with behavior and psychosocial outcomes (P < 0.05). Implementation process influenced the effectiveness of the ‘Choice, Control and Change’ intervention study. It is important to take into account the process components when interpreting the results of such research. PMID:25700557

  6. Predictive factors for pregnancy outcome following controlled ovarian stimulation and intrauterine insemination

    International Nuclear Information System (INIS)

    Yildrim, G.; Turkgeldi, L.S.; Koroglu, N.; Mervetalmac, A.

    2017-01-01

    To establish predictive factors for positive pregnancy outcome in cases of controlled ovarian stimulation and intrauterine insemination. Methods: The retrospective study was conducted at Kanuni Sultan Suleyman Training and Research Hospital and comprised subjects having undergone ovulation induction cycles and intrauterine insemination between June 2010 and June 2015. Data was analysed in terms of various parameters affecting clinical pregnancy rates. SPSS 23 was used for statistical analysis. Results: There were 475 patients having undergone a total of 923 cycles. Pregnancy was established in 133(28%) patients. Univariate analysis of biological/clinical variables revealed the presence of secondary infertility, high endometrial thickness, antral follicle number, post wash total motile sperm count and midluteal progesterone levels following intrauterine insemination to be associated with positive pregnancy outcomes (p<0.05 each). Multiple logistic regression analysis was performed to establish factors that affected the pregnancy rate. The aetiology and type of infertility and high midluteal progesterone levels following intrauterine insemination were found to be statistically significant predictors of pregnancy (p<0.05 each). Conclusion: The best chance of pregnancy was found in cases with anovulatory infertility, a history of prior pregnancy, and high midluteal progesterone levels following treatment with gonadotrophins and intrauterine insemination. (author)

  7. Control Multivariante Estadístico de Variables Discretas tipo Poisson

    OpenAIRE

    GARCIA BUSTOS, SANDRA LORENA

    2016-01-01

    En algunos casos, cuando el número de defectos de un proceso de producción tiene que ser controlada, la distribución de Poisson se emplea para modelar la frecuencia de estos defectos y para desarrollar un gráfico de control. En este trabajo se analiza el control de características de calidad p> 1 de Poisson . Cuando este control se necesita, hay dos enfoques principales: 1 - Un gráfico para cada variable de Poisson, el esquema múltiple.. 2 -. Sólo una gráfico para todas las variables, el sist...

  8. Active Power Filter DC Bus Voltage Piecewise Reaching Law Variable Structure Control

    Directory of Open Access Journals (Sweden)

    Baolian Liu

    2014-01-01

    Full Text Available The DC bus voltage stability control is one key technology to ensure that Active Power Filter (APF operates stably. The external disturbances such as power grid and load fluctuation and the system parameters changing may affect the stability of APF DC bus voltage and the normal operation of APF. The mathematical model of DC bus voltage is established according to power balance principle and a DC bus voltage piecewise reaching law variable structure control algorithm is proposed to solve the above problem, and the design method is given. The simulation and experiment results proved that the proposed variable structure control algorithm can eliminate the chattering problem existing in traditional variable structure control effectively, is insensitive to system disturbance, and has good robustness and fast dynamic response speed and stable DC bus voltage with small fluctuation. The above advantages ensure the compensation effect of APF.

  9. Sleep and circadian variability in people with delayed sleep-wake phase disorder versus healthy controls.

    Science.gov (United States)

    Burgess, Helen J; Park, Margaret; Wyatt, James K; Rizvydeen, Muneer; Fogg, Louis F

    2017-06-01

    To compare sleep and circadian variability in adults with delayed sleep-wake phase disorder (DSWPD) to healthy controls. Forty participants (22 DSWPD, 18 healthy controls) completed a ten-day protocol, consisting of DLMO assessments on two consecutive nights, a five-day study break, followed by two more DLMO assessments. All participants were instructed to sleep within one hour of their self-reported average sleep schedule for the last four days of the study break. We analyzed the participants' wrist actigraphy data during these four days to examine intraindividual variability in sleep timing, duration and efficiency. We also examined shifts in the DLMO from before and after the study break. Under the same conditions, people with DSWPD had significantly more variable wake times and total sleep time than healthy controls (p ≤ 0.015). Intraindividual variability in sleep onset time and sleep efficiency was similar between the two groups (p ≥ 0.30). The DLMO was relatively stable across the study break, with only 11% of controls but 27% of DSWPDs showed more than a one hour shift in the DLMO. Only in the DSWPD sample was greater sleep variability associated with a larger shift in the DLMO (r = 0.46, p = 0.03). These results suggest that intraindividual variability in sleep can be higher in DSWPD versus healthy controls, and this may impact variability in the DLMO. DSWPD patients with higher intraindividual variability in sleep are more likely to have a shifting DLMO, which could impact sleep symptoms and the optimal timing of light and/or melatonin treatment for DSWPD. Circadian Phase Assessments at Home, http://clinicaltrials.gov/show/NCT01487252, NCT01487252. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. A tool for protected area management: multivariate control charts 'cope' with rare variable communities.

    Science.gov (United States)

    Stringell, Thomas B; Bamber, Roger N; Burton, Mark; Lindenbaum, Charles; Skates, Lucie R; Sanderson, William G

    2013-06-01

    Performance assessment, impact detection, and the assessment of regulatory compliance are common scientific problems for the management of protected areas. Some habitats in protected areas, however, are rare and/or variable and are not often selected for study by ecologists because they preclude comparison with controls and high community variability makes meaningful change detection difficult. Shallow coastal saline lagoons are habitats that experience comparatively high levels of stress due to high physical variability. Lagoons are rare, declining habitats found in coastal regions throughout Europe (and elsewhere) where they are identified as one of the habitats most in need of protected area management. The infauna in the sediments of 25 lagoons were sampled. Temporal and spatial variation in three of these [protected] lagoons was investigated further over 5 years. In a multivariate analysis of community structure similarities were found between some lagoons, but in other cases communities were unique or specific to only two sites. The protected lagoons with these unique/specific communities showed significant temporal and spatial variation, yet none of the changes observed were attributed to human impacts and were interpreted as inherent variability. Multivariate control charts can operate without experimental controls and were used to assess community changes within the context of 'normal' lagoon variability. The aim of control chart analysis is to characterize background variability in a parameter and identify when a new observation deviates more than expected. In only 1 year was variability more than expected and corresponded with the coldest December in over 100 years. Multivariate control charts are likely to have wide application in the management of protected areas and other natural systems where variability and/or rarity preclude conventional analytical and experimental approaches but where assessments of condition, impact or regulatory compliance are

  11. Análisis de las variables de marketing que afectan al valor del cliente. La permanencia como variable controlable

    OpenAIRE

    Pedreño Santos, Ana

    2015-01-01

    To know how marketing variables affect customer value is essential for a company in order to be market and customer oriented, and to improve investment efficiency in both attracting and retaining customers. Thus, the assessment of the influence of marketing variables in customer value is of prime importance. This is recognized in many empirical studies of these variables, which address the impact of a single variable (or sets of a few variables) on customer value. A comprehensive, integrated ...

  12. Adaptive control of human action: The role of outcome representations and reward signals

    Directory of Open Access Journals (Sweden)

    Hans eMarien

    2013-09-01

    Full Text Available The present paper aims to advance the understanding of the control of human behavior by integrating two lines of literature that so far have led separate lives. First, one line of literature is concerned with the ideomotor principle of human behavior, according to which actions are represented in terms of their outcomes. The second line of literature mainly considers the role of reward signals in adaptive control. Here, we offer a combined perspective on how outcome representations and reward signals work together to modulate adaptive control processes. We propose that reward signals signify the value of outcome representations and facilitate the recruitment of control resources in situations where behavior needs to be maintained or adapted to attain the represented outcome. We discuss recent research demonstrating how adaptive control of goal-directed behavior may emerge when outcome representations are co-activated with positive reward signals.

  13. High performance continuously variable transmission control through robust-control-relevant model validation

    NARCIS (Netherlands)

    Oomen, T.A.E.; Meulen, van der S.H.

    2013-01-01

    Optimal operation of continuously variable transmissions (CVTs) is essential to meet tightening emission and fuel consumption requirements. This is achieved by accurately tracking a prescribed transmission ratio reference and simultaneously optimizing the internal efficiency of the CVT. To reduce

  14. Outcomes and Prognostic Variables in Adenoid Cystic Carcinoma of the Head and Neck: A Recent Experience

    International Nuclear Information System (INIS)

    Gomez, Daniel R.; Hoppe, Bradford S.; Wolden, Suzanne L.; Zhung, Joanne E.; Patel, Snehal G.; Kraus, Dennis H.; Shah, Jatin P.; Ghossein, Ronald A.; Lee, Nancy Y.

    2008-01-01

    Purpose: To analyze the recent experience of patients with adenoid cystic carcinoma treated with radiation therapy at Memorial Sloan-Kettering Cancer Center. Methods and Materials: From 1990 to 2004, a total of 59 patients with a diagnosis of primary adenoid cystic carcinoma of the head and neck received radiation therapy at our institution. The subsite distribution was oral cavity, 28% (n = 17); paranasal sinuses, 22% (n = 13); parotid, 14% (n = 8); submandibular, 14% (n = 8); oropharynx, 10% (n = 6); sublingual, 3% (n = 2); nasopharynx, 3% (n = 2); and other, 5% (n = 3). T Stage distribution was T1, 34% (n = 20); T2, 19% (n = 11); T3, 14% (n = 8); and T4, 34% (n = 20). Twenty-nine percent of patients (n = 17) were treated with intensity-modulated radiation therapy; 25% (n =15), with three-dimensional conformal therapy, and the remainder, with conventional techniques. Ninety percent (n = 53) of patients received treatment including the base of skull. Results: Median follow-up for surviving patients was 5.9 years. Five-year and 10-year rates of local control and distant metastases-free survival were 91%/81% and 81%/49%, respectively. Five-year and 10-year rates of disease-free and overall survival were 76%/40% and 87%/65%, respectively. On univariate analysis, stage T4 (p = 0.004) and gross/clinical nerve involvement (p = 0.002) were associated with decreased progression free survival, whereas stage T4 and lymph node involvement were associated with decreased overall survival (p = 0.046 and p < 0.001, respectively). Conclusions: Radiation therapy in combination with surgery produces excellent rates of local control, although distant metastases account for a high proportion of failures. Routine treatment to the base of skull reduces the significance of histologic perineural invasion, but major nerve involvement remains an adverse prognostic factor

  15. Self-Learning Variable Structure Control for a Class of Sensor-Actuator Systems

    Science.gov (United States)

    Chen, Sanfeng; Li, Shuai; Liu, Bo; Lou, Yuesheng; Liang, Yongsheng

    2012-01-01

    Variable structure strategy is widely used for the control of sensor-actuator systems modeled by Euler-Lagrange equations. However, accurate knowledge on the model structure and model parameters are often required for the control design. In this paper, we consider model-free variable structure control of a class of sensor-actuator systems, where only the online input and output of the system are available while the mathematic model of the system is unknown. The problem is formulated from an optimal control perspective and the implicit form of the control law are analytically obtained by using the principle of optimality. The control law and the optimal cost function are explicitly solved iteratively. Simulations demonstrate the effectiveness and the efficiency of the proposed method. PMID:22778633

  16. Semi-active variable stiffness vibration control of vehicle seat suspension using an MR elastomer isolator

    International Nuclear Information System (INIS)

    Du, Haiping; Li, Weihua; Zhang, Nong

    2011-01-01

    This paper presents a study on continuously variable stiffness control of vehicle seat suspension using a magnetorheological elastomer (MRE) isolator. A concept design for an MRE isolator is proposed in the paper and its behavior is experimentally evaluated. An integrated seat suspension model, which includes a quarter-car suspension and a seat suspension with a driver body model, is used to design a sub-optimal H ∞ controller for an active isolator. The desired control force generated by this active isolator is then emulated by the MRE isolator through its continuously variable stiffness property when the actuating condition is met. The vibration control effect of the MRE isolator is evaluated in terms of driver body acceleration responses under both bump and random road conditions. The results show that the proposed control strategy achieves better vibration reduction performance than conventional on–off control

  17. Nutritional variables and work-related accidents: a case-control study.

    Science.gov (United States)

    de Medeiros, M A T; Zangirolani, Lia Thieme Oikawa; Cordeiro, Ricardo Carlos; da Costa, Proença Rossana Pacheco; Diez-Garcia, Rosa Wanda

    2014-01-01

    Nutritional aspects are important for the prevention of diseases and disorders, and few studies have focused on the relationship between risk of work injury and nutritional variables. This study aimed to verify whether nutritional variables constitute risk factors for work-related accidents. 1,422 industrial workers (600 cases plus 822 controls). A case-control study was carried out in an industrial city in south-east Brazil. A multiple logistic regression model was adjusted using work-related accidents as the response variable and nutritional variables as predictors. The associations were assessed by Odds Ratio (OR), with a p-value work-related accidents were (a) attending formal education for an above average number of years (OR=0.91, pwork-related accidents. This indicates the need, during the formulation of policies for these kinds of government benefits, to include nutrition aspects in order to minimize work-related accidents risks.

  18. Monitoring and measurement of variables - assurance of observability and controllability of the reactor equipment

    International Nuclear Information System (INIS)

    Durnev, V.N.; Mitelman, M.G.

    2001-01-01

    The presentation presents main conclusions on the basis of analysis of the existing situation with assurance of observability and controllability of the reactor installation. A methodology of classification of variables of the controlled object state and proposals on selection and substantiation of measurement and inspection monitoring techniques is given. Main problems associated with assurance of observability and controllability of the reactor installation are presented for various operation modes. (Authors)

  19. Resistance Torque Based Variable Duty-Cycle Control Method for a Stage II Compressor

    Science.gov (United States)

    Zhong, Meipeng; Zheng, Shuiying

    2017-07-01

    The resistance torque of a piston stage II compressor generates strenuous fluctuations in a rotational period, and this can lead to negative influences on the working performance of the compressor. To restrain the strenuous fluctuations in the piston stage II compressor, a variable duty-cycle control method based on the resistance torque is proposed. A dynamic model of a stage II compressor is set up, and the resistance torque and other characteristic parameters are acquired as the control targets. Then, a variable duty-cycle control method is applied to track the resistance torque, thereby improving the working performance of the compressor. Simulated results show that the compressor, driven by the proposed method, requires lower current, while the rotating speed and the output torque remain comparable to the traditional variable-frequency control methods. A variable duty-cycle control system is developed, and the experimental results prove that the proposed method can help reduce the specific power, input power, and working noise of the compressor to 0.97 kW·m-3·min-1, 0.09 kW and 3.10 dB, respectively, under the same conditions of discharge pressure of 2.00 MPa and a discharge volume of 0.095 m3/min. The proposed variable duty-cycle control method tracks the resistance torque dynamically, and improves the working performance of a Stage II Compressor. The proposed variable duty-cycle control method can be applied to other compressors, and can provide theoretical guidance for the compressor.

  20. Control of variable speed wind turbines with doubly-fed induction generators

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, A.D.; Soerensen, P.; Iov, F.; Blaabjerg, F.

    2005-07-01

    The paper presents an overall control method for variable speed pitch controlled wind turbines with doubly-fed induction generators (DFIG). Emphasis is on control strategies and algorithms applied at each hierarchical control level of the wind turbine. The objectives of the control system are: 1) to control the power drawn from the wind turbine in order to track the wind turbine maximum power operation point, 2) to limit the power in case of large wind speeds, and 3) to control the reactive power interchanged between the wind turbine generator and the grid. The present control method is designed for normal continuous operations. The strongest feature of the implemented control method is that it allows the turbine to operate with the optimum power efficiency over a wide range of wind speeds. The model of the variable speed, variable pitch wind turbine with doubly-fed induction generator is implemented in the dynamic power system simulation tool DlgSILENT PowerFactory which allows investigation of the dynamic performance of grid-connected wind turbines within realistic electrical grid models. Simulation results are presented and analysed in different normal operating conditions. (author)

  1. Robust predictive control strategy applied for propofol dosing using BIS as a controlled variable during anesthesia

    NARCIS (Netherlands)

    Ionescu, Clara A.; De Keyser, Robin; Torrico, Bismark Claure; De Smet, Tom; Struys, Michel M. R. F.; Normey-Rico, Julio E.

    This paper presents the application of predictive control to drug dosing during anesthesia in patients undergoing surgery. The performance of a generic predictive control strategy in drug dosing control, with a previously reported anesthesia-specific control algorithm, has been evaluated. The

  2. Evidence for a time-invariant phase variable in human ankle control.

    Directory of Open Access Journals (Sweden)

    Robert D Gregg

    Full Text Available Human locomotion is a rhythmic task in which patterns of muscle activity are modulated by state-dependent feedback to accommodate perturbations. Two popular theories have been proposed for the underlying embodiment of phase in the human pattern generator: a time-dependent internal representation or a time-invariant feedback representation (i.e., reflex mechanisms. In either case the neuromuscular system must update or represent the phase of locomotor patterns based on the system state, which can include measurements of hundreds of variables. However, a much simpler representation of phase has emerged in recent designs for legged robots, which control joint patterns as functions of a single monotonic mechanical variable, termed a phase variable. We propose that human joint patterns may similarly depend on a physical phase variable, specifically the heel-to-toe movement of the Center of Pressure under the foot. We found that when the ankle is unexpectedly rotated to a position it would have encountered later in the step, the Center of Pressure also shifts forward to the corresponding later position, and the remaining portion of the gait pattern ensues. This phase shift suggests that the progression of the stance ankle is controlled by a biomechanical phase variable, motivating future investigations of phase variables in human locomotor control.

  3. Chaos control and generalized projective synchronization of heavy symmetric chaotic gyroscope systems via Gaussian radial basis adaptive variable structure control

    International Nuclear Information System (INIS)

    Farivar, Faezeh; Aliyari Shoorehdeli, Mahdi; Nekoui, Mohammad Ali; Teshnehlab, Mohammad

    2012-01-01

    Highlights: ► A systematic procedure for GPS of unknown heavy chaotic gyroscope systems. ► Proposed methods are based on Lyapunov stability theory. ► Without calculating Lyapunov exponents and Eigen values of the Jacobian matrix. ► Capable to extend for a variety of chaotic systems. ► Useful for practical applications in the future. - Abstract: This paper proposes the chaos control and the generalized projective synchronization methods for heavy symmetric gyroscope systems via Gaussian radial basis adaptive variable structure control. Because of the nonlinear terms of the gyroscope system, the system exhibits chaotic motions. Occasionally, the extreme sensitivity to initial states in a system operating in chaotic mode can be very destructive to the system because of unpredictable behavior. In order to improve the performance of a dynamic system or avoid the chaotic phenomena, it is necessary to control a chaotic system with a periodic motion beneficial for working with a particular condition. As chaotic signals are usually broadband and noise like, synchronized chaotic systems can be used as cipher generators for secure communication. This paper presents chaos synchronization of two identical chaotic motions of symmetric gyroscopes. In this paper, the switching surfaces are adopted to ensure the stability of the error dynamics in variable structure control. Using the neural variable structure control technique, control laws are established which guarantees the chaos control and the generalized projective synchronization of unknown gyroscope systems. In the neural variable structure control, Gaussian radial basis functions are utilized to on-line estimate the system dynamic functions. Also, the adaptation laws of the on-line estimator are derived in the sense of Lyapunov function. Thus, the unknown gyro systems can be guaranteed to be asymptotically stable. Also, the proposed method can achieve the control objectives. Numerical simulations are presented to

  4. Modelling and control of variable speed wind turbines for power system studies

    DEFF Research Database (Denmark)

    Michalke, Gabriele; Hansen, Anca Daniela

    2010-01-01

    and implemented in the power system simulation tool DIgSILENT. Important issues like the fault ride-through and grid support capabilities of these wind turbine concepts are addressed. The paper reveals that advanced control of variable speed wind turbines can improve power system stability. Finally......, it will be shown in the paper that wind parks consisting of variable speed wind turbines can help nearby connected fixed speed wind turbines to ride-through grid faults. Copyright © 2009 John Wiley & Sons, Ltd.......Modern wind turbines are predominantly variable speed wind turbines with power electronic interface. Emphasis in this paper is therefore on the modelling and control issues of these wind turbine concepts and especially on their impact on the power system. The models and control are developed...

  5. Variable speed wind turbine generator system with current controlled voltage source inverter

    International Nuclear Information System (INIS)

    Muyeen, S.M.; Al-Durra, Ahmed; Tamura, J.

    2011-01-01

    highlights: → Current controlled voltage source inverter scheme for wind power application. → Low voltage ride through of wind farm. → Variable speed wind turbine driven permanent magnet synchronous generator-operation and control. -- Abstract: The present popular trend of wind power generation is to use variable speed wind turbine (VSWT) driving a doubly fed induction generator (DFIG), wound field synchronous generator (WFSG) or permanent magnet synchronous generator (PMSG). Among them, stability analyses of DFIG type of VSWT have already been reported in many literatures. However, transient stability and low voltage ride through (LVRT) characteristics analyses for synchronous generator type of VSWT is not sufficient enough. This paper focuses on detailed LVRT characteristic analysis of variable speed wind turbine driving a PMSG (VSWT-PMSG) with current controlled voltage source inverter (CC-VSI). Modeling and suitable control strategies for overall system are developed to augment the low voltage ride through capability of variable speed wind generator, considering recent wind farm grid code. Both symmetrical and unsymmetrical faults are analyzed as network disturbances in this paper. The permanent fault due to unsuccessful reclosing of circuit breakers is taken into consideration, which is a salient feature of this study. Moreover, the dynamic characteristic is analyzed using real wind speed data measured in Hokkaido Island, Japan. The proposed control scheme is simulated by using the standard power system simulation package PSCAD/EMTDC and results are verified by comparing that of voltage controlled voltage source inverter scheme available in power system literature.

  6. Variable speed wind turbine generator system with current controlled voltage source inverter

    Energy Technology Data Exchange (ETDEWEB)

    Muyeen, S.M., E-mail: muyeen0809@yahoo.co [Dept. of Electrical Engineering, Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Al-Durra, Ahmed [Dept. of Electrical Engineering, The Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Tamura, J. [Dept. of EEE, Kitami Institute of Technology, 165 Koen-cho, Kitami 090-8507 (Japan)

    2011-07-15

    highlights: {yields} Current controlled voltage source inverter scheme for wind power application. {yields} Low voltage ride through of wind farm. {yields} Variable speed wind turbine driven permanent magnet synchronous generator-operation and control. -- Abstract: The present popular trend of wind power generation is to use variable speed wind turbine (VSWT) driving a doubly fed induction generator (DFIG), wound field synchronous generator (WFSG) or permanent magnet synchronous generator (PMSG). Among them, stability analyses of DFIG type of VSWT have already been reported in many literatures. However, transient stability and low voltage ride through (LVRT) characteristics analyses for synchronous generator type of VSWT is not sufficient enough. This paper focuses on detailed LVRT characteristic analysis of variable speed wind turbine driving a PMSG (VSWT-PMSG) with current controlled voltage source inverter (CC-VSI). Modeling and suitable control strategies for overall system are developed to augment the low voltage ride through capability of variable speed wind generator, considering recent wind farm grid code. Both symmetrical and unsymmetrical faults are analyzed as network disturbances in this paper. The permanent fault due to unsuccessful reclosing of circuit breakers is taken into consideration, which is a salient feature of this study. Moreover, the dynamic characteristic is analyzed using real wind speed data measured in Hokkaido Island, Japan. The proposed control scheme is simulated by using the standard power system simulation package PSCAD/EMTDC and results are verified by comparing that of voltage controlled voltage source inverter scheme available in power system literature.

  7. Complex state variable- and disturbance observer-based current controllers for AC drives

    DEFF Research Database (Denmark)

    Dal, Mehmet; Teodorescu, Remus; Blaabjerg, Frede

    2013-01-01

    In vector-controlled AC drives, the design of current controller is usually based on a machine model defined in synchronous frame coordinate, where the drive performance may be degraded by both the variation of the machine parameters and the cross-coupling between the d- and q-axes components...... of the stator current. In order to improve the current control performance an alternative current control strategy was proposed previously aiming to avoid the undesired cross-coupling and non-linearities between the state variables. These effects are assumed as disturbances arisen in the closed-loop path...... of the parameter and the cross-coupling effect. Moreover, it provides a better performance, smooth and low noisy operation with respect to the complex variable controller....

  8. Wind Turbine Generator Modeling and Simulation Where Rotational Speed is the Controlled Variable

    DEFF Research Database (Denmark)

    Mihet-Popa, Lucian; Blaabjerg, Frede; Boldea, Ion

    2004-01-01

    the interaction between a wind turbine and the power system. The model is intended to simulate the behaviour of the wind turbine using induction generators both during normal operation. Sample simulation results for two induction generators (2/0.5 MW) validate the fundamental issues.......To optimise the power produced in a wind turbine, the speed of the turbine should vary with the wind speed. A simple control method is proposed that will allow an induction machine to run a turbine at its maximum power coefficient. Various types of power control strategies have been suggested...... for application in variable speed wind turbines. The usual strategy is to control the power or the torque acting on the wind turbine shafts. This paper presents an alternative control strategy, where the rotational speed is the controlled variable. The paper describes a model, which is being developed to simulate...

  9. A novel technology for control of variable speed pumped storage power plant

    Institute of Scientific and Technical Information of China (English)

    Seyed Mohammad Hassan Hosseini; Mohammad Reza Semsar

    2016-01-01

    Variable speed pumped storage machines are used extensively in wind power plant and pumped storage power plant. This paper presents direct torque and flux control (DTFC) of a variable speed pumped storage power plant (VSPSP). By this method both torque and flux have been applied to control the VSPSP. The comparison between VSPSP’s control strategies is studied. At the first, a wind turbine with the capacity 2.2 kW and DTFC control strategies simulated then a 250 MW VSPSP is simulated with all of its parts (including electrical, mechanical, hydraulic and its control system) by MATLAB software. In all of simulations, both converters including two-level voltage source converter (2LVSC) and three-level voltage source converter (3LVSC) are applied. The results of applying 2LVSC and 3LVSC are the rapid dynamic responses with better efficiency, reducing the total harmonic distortion (THD) and ripple of rotor torque and flux.

  10. Tuning method for multi-variable control system with PID controllers

    International Nuclear Information System (INIS)

    Fujiwara, Toshitaka

    1983-01-01

    Control systems, including thermal and nuclear power plants, generally and mainly use PID controllers consisting of proportional, integral and differential actions. These systems consist of multiple control loops which interfere with each other. Therefore, it is present status that the fine control of the system is carried out by the trial and error method because the adjusting procedure for a single control loop cannot be applied to a multi-loop system in most cases. In this report, a method to effectively adjust PID controller parameters in a short time in a control system which consists of multi-loops that interfere with each other. This method makes adjustment by using the control area as the evaluation function, which is the time-dependent integration of control deviation, the input to the PID controllers. In other words, the evaluation function is provided for each control result for every parameter (gain constant, reset rate, and differentiation time), and all parameters are simultaneously changed in the direction of minimizing the values of these evaluation functions. In the report, the principle of tuning method, the evaluation function for each of three parameters, and the adjusting system configuration for separately using for actual plant tuning and for control system design are described. It also shows the examples of application to the actual tuning of the control system for a thermal power plant and to a control system design. (Wakatsuki, Y.)

  11. Measuring the Impact of Gastrointestinal Variables on the Systemic Outcome of Two Suspensions of Posaconazole by a PBPK Model.

    Science.gov (United States)

    Hens, Bart; Talattof, Arjang; Paixão, Paulo; Bermejo, Marival; Tsume, Yasuhiro; Löbenberg, Raimar; Amidon, Gordon L

    2018-03-29

    For the last two decades, the application of physiologically based pharmacokinetic (PBPK) models has grown exponentially in the field of oral absorption and in a regulatory context. Although these models are widely used, their predictive power should be validated and optimized in order to rely on these models and to know exactly what is going on "under the hood". In this study, an automated sensitivity analysis (ASA) was performed for 11 gastrointestinal (GI) variables that are integrated into the PBPK software program Simcyp®. The model of interest was a previously validated workspace that was able to predict the intraluminal and systemic behavior of two different suspensions of posaconazole in the Simcyp® Simulator. The sensitivity of the following GI parameters was evaluated in this model: gastric and duodenal pH, gastric and duodenal bicarbonate concentrations (reflecting buffer capacity), duodenal bile salts concentration, gastric emptying, the interdigestive migrating motor complex (IMMC), small intestinal transit time (SITT), gastric and jejunal volumes, and permeability. The most sensitive parameters were gastric/duodenal pH and gastric emptying, for both suspensions. The outcome of the sensitivity analyses highlights the important GI variables that must be integrated into an in vivo predictive dissolution test to help and create a rational and scientific framework/design for product development of novel and generic drug products.

  12. Variable Structure Disturbance Rejection Control for Nonlinear Uncertain Systems with State and Control Delays via Optimal Sliding Mode Surface Approach

    Directory of Open Access Journals (Sweden)

    Jing Lei

    2013-01-01

    Full Text Available The paper considers the problem of variable structure control for nonlinear systems with uncertainty and time delays under persistent disturbance by using the optimal sliding mode surface approach. Through functional transformation, the original time-delay system is transformed into a delay-free one. The approximating sequence method is applied to solve the nonlinear optimal sliding mode surface problem which is reduced to a linear two-point boundary value problem of approximating sequences. The optimal sliding mode surface is obtained from the convergent solutions by solving a Riccati equation, a Sylvester equation, and the state and adjoint vector differential equations of approximating sequences. Then, the variable structure disturbance rejection control is presented by adopting an exponential trending law, where the state and control memory terms are designed to compensate the state and control delays, a feedforward control term is designed to reject the disturbance, and an adjoint compensator is designed to compensate the effects generated by the nonlinearity and the uncertainty. Furthermore, an observer is constructed to make the feedforward term physically realizable, and thus the dynamical observer-based dynamical variable structure disturbance rejection control law is produced. Finally, simulations are demonstrated to verify the effectiveness of the presented controller and the simplicity of the proposed approach.

  13. The optimal operation of cooling tower systems with variable-frequency control

    Science.gov (United States)

    Cao, Yong; Huang, Liqing; Cui, Zhiguo; Liu, Jing

    2018-02-01

    This study investigates the energy performance of chiller and cooling tower systems integrated with variable-frequency control for cooling tower fans and condenser water pumps. With regard to an example chiller system serving an office building, Chiller and cooling towers models were developed to assess how different variable-frequency control methods of cooling towers fans and condenser water pumps influence the trade-off between the chiller power, pump power and fan power under various operating conditions. The matching relationship between the cooling tower fans frequency and condenser water pumps frequency at optimal energy consumption of the system is introduced to achieve optimum system performance.

  14. Fuzzy variable impedance control based on stiffness identification for human-robot cooperation

    Science.gov (United States)

    Mao, Dachao; Yang, Wenlong; Du, Zhijiang

    2017-06-01

    This paper presents a dynamic fuzzy variable impedance control algorithm for human-robot cooperation. In order to estimate the intention of human for co-manipulation, a fuzzy inference system is set up to adjust the impedance parameter. Aiming at regulating the output fuzzy universe based on the human arm’s stiffness, an online stiffness identification method is developed. A drag interaction task is conducted on a 5-DOF robot with variable impedance control. Experimental results demonstrate that the proposed algorithm is superior.

  15. The Effect of Locus of Control, Self-Efficacy, and Gender-Role Identity on Academic Performance Outcomes of Female College Students

    Science.gov (United States)

    Sierra, Jade Simone

    2013-01-01

    This quantitative study investigated the predictive worthiness of the predictor variable indices--locus of control, self-efficacy, and gender identity--to ascertain if elevated levels of the predictors influence academic performance outcomes (individually as well as interactionally). The study theorized that students with increased levels of locus…

  16. The coping with depression course: Short term outcomes and mediating effects of a randomized controlled trial in the treatment of subclinical depression

    NARCIS (Netherlands)

    Allart-van Dam, E.; Hosman, C.M.H.; Hoogduin, C.A.L.; Schaap, C.P.D.R.

    2003-01-01

    This article reports on a randomized controlled trial investigating the short-term effectiveness of the Coping With Depression course in a sample of adults seriously at risk of developing major depression. In addition, possible mediating properties of several proximal outcome variables were

  17. The Coping with Depression course : Short-term outcomes and mediating effects of a randomized controlled trial in the treatment of subclinical depression

    NARCIS (Netherlands)

    Allart-van Dam, E; Hosman, CMH; Hoogduin, CAL; Schaap, CPDR

    2003-01-01

    This article reports on a randomized controlled trial investigating the short-term effectiveness of the Coping With Depression course in a sample of adults seriously at risk of developing major depression. In addition, possible mediating properties of several proximal outcome variables were

  18. Differential Responding by Rhesus Monkeys (Macaca mulatta and Humans (Homo sapiens to Variable Outcomes in the Assurance Game

    Directory of Open Access Journals (Sweden)

    Audrey E. Parrish

    2014-08-01

    Full Text Available Behavioral flexibility in how one responds to variable partner play can be examined using economic coordination games in which subjects play against a variety of partners and therefore may need to alter their behavior to produce the highest payoff. But how do we study this behavioral flexibility once players have settled on a response? Here, we investigated how responding by rhesus monkeys (Macaca mulatta and humans (Homo sapiens playing a computerized single-player version of a coordination game, the Assurance game, changed as a function of the variable responses (Stag/Hare generated by multiple simulations (SIMs. We were interested in whether individuals could track and differentially respond to changing frequencies of Stag and Hare play by the SIMs, especially with regard to the payoff dominant (Stag-Stag outcome, something that could not be done with real partners as they quickly settled on the Stag response. For both monkeys and humans, there was a linear relationship between proportion of Stag play by the subject and the likelihood of the Stag choice by the SIM such that both species increased their use of Stag as the SIM increased its use of the Stag response. However, humans more closely matched their proportion of Stag responses to that of the SIM, whereas monkeys adopted a different, but equally effective, strategy of exploiting the higher-paying Stag alternative. These results suggest that monkeys and humans demonstrate sensitivity to a dynamic game environment in which they encounter variable contingencies for the same response options, although they may employ different strategies to maximize reward.

  19. Modeling, Simulation and Control of Matrix Convert for Variable Speed Wind Turbine System

    Directory of Open Access Journals (Sweden)

    M. Alizadeh Moghadam

    2015-09-01

    Full Text Available This paper presents modeling, simulation and control of matrix converter (MC for variable speed wind turbine (VSWT system including permanent magnet synchronous generator (PMSG. At a given wind velocity, the power available from a wind turbine is a function of its shaft speed. In order to track maximum power, the MC adjusts the PMSG shaft speed.The proposed control system allowing independent control maximum power point tracking (MPPT of generator side and regulate reactive power of grid side for the operation of the VSWT system. The MPPT is implemented by a new control system. This control system is based on control of zero d-axis current (ZDC. The ZDC control can be realized by transfer the three-phase stator current in the stationary reference frame into d-and q-axis components in the synchronous reference frame. Also this paper is presented, a novel control strategy to regulate the reactive power supplied by a variable speed wind energy conversion system. This control strategy is based on voltage oriented control (VOC. The simulation results based on Simulink/Matlab software show that the controllers can extract maximum power and regulate reactive power under varying wind velocities.

  20. What Variables Are Associated With the Outcome of Arthroscopic Lysis and Lavage Surgery for Internal Derangement of the Temporomandibular Joint?

    Science.gov (United States)

    Haeffs, Tyler H; D'Amato, Lindsay N; Khawaja, Shehryar N; Keith, David A; Scrivani, Steven J

    2018-04-26

    Arthroscopic lysis and lavage surgery (AS) is an effective modality that can decrease pain and increase maximum interincisal opening (MIO) in patients with internal derangement (ID) of the temporomandibular joint (TMJ). However, some patients remain in pain or have limited mandibular range of motion despite AS. The purpose of this study was to determine the effectiveness, prevalence of adverse effects, and predictors of response to TMJ AS in patients with TMJ arthralgia and ID. A retrospective cohort study was conducted using data of patients who had undergone AS by a single surgeon (D.A.K.) from September 2010 to April 2015 in the Department of Oral and Maxillofacial Surgery at Massachusetts General Hospital (Boston, MA). Variables, including demographic data, medical history, and clinical presentation, were extracted and analyzed. Criteria for surgical success were defined as a postoperative MIO of at least 35 mm and a postoperative pain level no higher than 3 on an 11-point Likert-type numeric verbal pain rating scale. Appropriate descriptive and analytic statistics were computed and significance was set at a P value less than .05. Of the 247 participants, 226 (91.5%) were women. The mean age of the sample was 38 ± 15.4 years. Successful surgical outcome was achieved in 62.3% of patients. Based on logistic regression analysis, higher initial mean pain score and concurrent use of benzodiazepines were the only variables that predicted an unsuccessful surgical outcome (P < .001; P = .005). Adverse effects were reported by 13.4% of patients, the most common being postoperative increase in pain (13.4%), temporary malocclusion (1.2%), and temporary paresthesia in the preauricular region (0.4%). The results from this study indicate that in patients with ID of the TMJ unresponsive to noninvasive treatments, high initial pain scores and concurrent use of benzodiazepines are correlated with an unsuccessful outcome after AS. Copyright © 2018. Published by

  1. Connected variable speed limits control and vehicle acceleration control to resolve moving jams

    NARCIS (Netherlands)

    Wang, M.; Daamen, W.; Hoogendoorn, S.P.; Van Arem, B.

    2015-01-01

    The vision of intelligent vehicles traveling in road networks has prompted numerous concepts to control future traffic flow, one of which is the in-vehicle actuation of traffic control signals. The key of this concept is using intelligent vehicles as actuators for traffic control systems, replacing

  2. Modeling and control of PMSG-based variable-speed wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hong-Woo; Ko, Hee-Sang [Wind Energy Research Center, Korea Institute of Energy Research, Yuseong-gu Jang-Dong 71-2,305-343 Daejeon (Korea); Kim, Sung-Soo [Chungbuk National University (Korea)

    2010-01-15

    This paper presents a control scheme of a variable-speed wind turbine with a permanent-magnetic synchronous generator (PMSG) and full-scale back-to-back voltage source converter. A comprehensive dynamical model of the PMSG wind turbine and its control scheme is presented. The control scheme comprises both the wind-turbine control itself and the power-converter control. In addition, since the PMSG wind turbine is able to support actively the grid due to its capability to control independently active and reactive power production to the imposed set-values with taking into account its operating state and limits, this paper presents the supervisory reactive power control scheme in order to regulate/contribute the voltage at a remote location. The ability of the control scheme is assessed and discussed by means of simulations, based on a candidate site of the offshore wind farm in Jeju, Korea. (author)

  3. Theory of planned behaviour variables and objective walking behaviour do not show seasonal variation in a randomised controlled trial.

    Science.gov (United States)

    Williams, Stefanie L; French, David P

    2014-02-05

    Longitudinal studies have shown that objectively measured walking behaviour is subject to seasonal variation, with people walking more in summer compared to winter. Seasonality therefore may have the potential to bias the results of randomised controlled trials if there are not adequate statistical or design controls. Despite this there are no studies that assess the impact of seasonality on walking behaviour in a randomised controlled trial, to quantify the extent of such bias. Further there have been no studies assessing how season impacts on the psychological predictors of walking behaviour to date. The aim of the present study was to assess seasonal differences in a) objective walking behaviour and b) Theory of Planned Behaviour (TPB) variables during a randomised controlled trial of an intervention to promote walking. 315 patients were recruited to a two-arm cluster randomised controlled trial of an intervention to promote walking in primary care. A series of repeated measures ANCOVAs were conducted to examine the effect of season on pedometer measures of walking behaviour and TPB measures, assessed immediately post-intervention and six months later. Hierarchical regression analyses were conducted to assess whether season moderated the prediction of intention and behaviour by TPB measures. There were no significant differences in time spent walking in spring/summer compared to autumn/winter. There was no significant seasonal variation in most TPB variables, although the belief that there will be good weather was significantly higher in spring/summer (F = 19.46, p behaviour, or moderate the effects of TPB variables on intention or behaviour. Seasonality does not influence objectively measured walking behaviour or psychological variables during a randomised controlled trial. Consequently physical activity behaviour outcomes in trials will not be biased by the season in which they are measured. Previous studies may have overestimated the extent of

  4. The Selection, Use, and Reporting of Control Variables in International Business Research

    DEFF Research Database (Denmark)

    Nielsen, Bo Bernhard; Raswant, Arpit

    2018-01-01

    This study explores the selection, use, and reporting of control variables in studies published in the leading international business (IB) research journals. We review a sample of 246 empirical studies published in the top five IB journals over the period 2012–2015 with particular emphasis...... on selection, use, and reporting of controls. Approximately 83% of studies included only half of what we consider Minimum Standard of Practice with regards to controls, whereas only 38% of the studies met the 75% threshold. We provide recommendations on how to effectively identify, use and report controls...

  5. Performance comparison of control schemes for variable-speed wind turbines

    Science.gov (United States)

    Bottasso, C. L.; Croce, A.; Savini, B.

    2007-07-01

    We analyze the performance of different control schemes when applied to the regulation problem of a variable-speed representative wind turbine. In particular, we formulate and compare a wind-scheduled PID, a LQR controller and a novel adaptive non-linear model predictive controller, equipped with observers of the tower states and wind. The simulations include gusts and turbulent winds of varying intensity in nominal as well as off-design operating conditions. The experiments highlight the possible advantages of model-based non-linear control strategies.

  6. Performance comparison of control schemes for variable-speed wind turbines

    International Nuclear Information System (INIS)

    Bottasso, C L; Croce, A; Savini, B

    2007-01-01

    We analyze the performance of different control schemes when applied to the regulation problem of a variable-speed representative wind turbine. In particular, we formulate and compare a wind-scheduled PID, a LQR controller and a novel adaptive non-linear model predictive controller, equipped with observers of the tower states and wind. The simulations include gusts and turbulent winds of varying intensity in nominal as well as off-design operating conditions. The experiments highlight the possible advantages of model-based non-linear control strategies

  7. UDE-based control of variable-speed wind turbine systems

    Science.gov (United States)

    Ren, Beibei; Wang, Yeqin; Zhong, Qing-Chang

    2017-01-01

    In this paper, the control of a PMSG (permanent magnet synchronous generator)-based variable-speed wind turbine system with a back-to-back converter is considered. The uncertainty and disturbance estimator (UDE)-based control approach is applied to the regulation of the DC-link voltage and the control of the RSC (rotor-side converter) and the GSC (grid-side converter). For the rotor-side controller, the UDE-based vector control is developed for the RSC with PMSG control to facilitate the application of the MPPT (maximum power point tracking) algorithm for the maximum wind energy capture. For the grid-side controller, the UDE-based vector control is developed to control the GSC with the power reference generated by a UDE-based DC-link voltage controller. Compared with the conventional vector control, the UDE-based vector control can achieve reliable current decoupling control with fast response. Moreover, the UDE-based DC-link voltage regulation can achieve stable DC-link voltage under model uncertainties and external disturbances, e.g. wind speed variations. The effectiveness of the proposed UDE-based control approach is demonstrated through extensive simulation studies in the presence of coupled dynamics, model uncertainties and external disturbances under varying wind speeds. The UDE-based control is able to generate more energy, e.g. by 5% for the wind profile tested.

  8. Intrinsic movement variability at work. How long is the path from motor control to design engineering?

    Science.gov (United States)

    Gaudez, C; Gilles, M A; Savin, J

    2016-03-01

    For several years, increasing numbers of studies have highlighted the existence of movement variability. Before that, it was neglected in movement analysis and it is still almost completely ignored in workstation design. This article reviews motor control theories and factors influencing movement execution, and indicates how intrinsic movement variability is part of task completion. These background clarifications should help ergonomists and workstation designers to gain a better understanding of these concepts, which can then be used to improve design tools. We also question which techniques--kinematics, kinetics or muscular activity--and descriptors are most appropriate for describing intrinsic movement variability and for integration into design tools. By this way, simulations generated by designers for workstation design should be closer to the real movements performed by workers. This review emphasises the complexity of identifying, describing and processing intrinsic movement variability in occupational activities. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  9. Halo control, beam matching, and new dynamical variables for beam distributions

    International Nuclear Information System (INIS)

    Lysenko, W.; Parsa, Z.

    1997-01-01

    We present the status of our work on physics models that relate release to the understanding and control of beam halo, which is a cause of particle loss in high power ion linear accelerators. We can minimize these particle losses, even in the presence of nonlinearities, by ensuring the beam is matched to high order. Our goal is to determine new dynamical variables that enable us to more directly solve for the evolution of the halo. We considered moments and several new variables, using a Lie-Poisson formulation whenever possible. Using symbolic techniques, we computed high-order matches and mode invariants (analogs of moment invariants) in the new variables. A promising new development developments is that of the variables we call weighted moments, which allow us to compute high-order nonlinear effects (like halos) while making use of well-developed existing results and computational techniques developed for studying first order effects. copyright 1997 American Institute of Physics

  10. Study and experimental verification of control tuning strategies in a variable speed wind energy conversion system

    Energy Technology Data Exchange (ETDEWEB)

    Zaragoza, Jordi; Pou, Josep; Arias, Antoni [Electronic Engineering Dept., Technical University of Catalonia, Campus Terrassa, C. Colom 1, 08222 Terrassa (Spain); Spiteri, Cyril [Department of Industrial Electrical Power Conversion, University of Malta, Faculty of Engineering, Msida (Malta); Robles, Eider; Ceballos, Salvador [Energy Unit, Robotiker-Tecnalia Technology Corporation, Zamudio, Basque Country (Spain)

    2011-05-15

    This paper analyzes and compares different control tuning strategies for a variable speed wind energy conversion system (WECS) based on a permanent-magnet synchronous generator (PMSG). The aerodynamics of the wind turbine (WT) and a PMSG have been modeled. The control strategy used in this research is composed of three regulators, which may be based on either linear or nonlinear controllers. In this analysis, proportional-integral (PI) linear controllers have been used. Two different tuning strategies are analyzed and compared. The main goal is to enhance the overall performance by achieving a low sensitivity to disturbances and minimal overshoot under variable operating conditions. Finally, the results have been verified by an experimental WECS laboratory prototype. (author)

  11. Potential electricity savings by variable speed control of compressor for air conditioning systems

    Energy Technology Data Exchange (ETDEWEB)

    Nasution, Henry [Bung Hatta University, Department of Mechanical Engineering, Faculty of Industrial Engineering, Padang, West Sumatera (Indonesia); Wan Hassan, Mat Nawi [Universiti Teknologi Malaysia, Faculty of Mechanical Engineering, Skudai, Johor Bahru-Darul Ta' zim (Malaysia)

    2006-05-15

    The potential of a variable-speed compressor running on a controller to provide enhanced load-matching capability, energy saving and thermal comfort for application in air-conditioning system is demonstrated. An air-conditioning system, originally operated on a constant speed mode, is retrofitted with an inverter and a PID controller. The system was installed to a thermal environmental room together with a data acquisition system to monitor energy consumption and temperature of the room. Measurements were taken 2 h daily at a time interval of 5 min for an on/off and an inverter variable-speed conditions. The results indicate that thermal comfort of the room together with energy saving can be obtained through a proper selection of K for the controller. At a temperature setting of 22 C, the energy saving for the system is estimated to reach 25.3% for PID controllers. (orig.)

  12. A New Turbo-shaft Engine Control Law during Variable Rotor Speed Transient Process

    Science.gov (United States)

    Hua, Wei; Miao, Lizhen; Zhang, Haibo; Huang, Jinquan

    2015-12-01

    A closed-loop control law employing compressor guided vanes is firstly investigated to solve unacceptable fuel flow dynamic change in single fuel control for turbo-shaft engine here, especially for rotorcraft in variable rotor speed process. Based on an Augmented Linear Quadratic Regulator (ALQR) algorithm, a dual-input, single-output robust control scheme is proposed for a turbo-shaft engine, involving not only the closed loop adjustment of fuel flow but also that of compressor guided vanes. Furthermore, compared to single fuel control, some digital simulation cases using this new scheme about variable rotor speed have been implemented on the basis of an integrated system of helicopter and engine model. The results depict that the command tracking performance to the free turbine rotor speed can be asymptotically realized. Moreover, the fuel flow transient process has been significantly improved, and the fuel consumption has been dramatically cut down by more than 2% while keeping the helicopter level fight unchanged.

  13. Design of a variable width pulse generator feasible for manual or automatic control

    Energy Technology Data Exchange (ETDEWEB)

    Vegas, I., E-mail: ignacio.vegas@pas.ucm.es; Antoranz, P.; Miranda, J.M.; Franco, F.J.

    2017-01-01

    A variable width pulse generator featuring more than 4-V peak amplitude and less than 10-ns FWHM is described. In this design the width of the pulses is controlled by means of the control signal slope. Thus, a variable transition time control circuit (TTCC) is also developed, based on the charge and discharge of a capacitor by means of two tunable current sources. Additionally, it is possible to activate/deactivate the pulses when required, therefore allowing the creation of any desired pulse pattern. Furthermore, the implementation presented here can be electronically controlled. In conclusion, due to its versatility, compactness and low cost it can be used in a wide variety of applications.

  14. Indices of language outcome 11 years after intrathecal chemotherapy for acute lymphoblastic leukemia: a sibling case-control study.

    Science.gov (United States)

    Lewis, Fiona M; Su, I-Fan; Murdoch, Bruce E

    2012-03-01

    Studies are emerging that suggest that major language indices do not differentiate children treated for acute lymphoblastic leukemia (ALL) with risk-adapted intrathecal chemotherapy (ITC) from control children matched on age, gender, and educational level. No study to date has controlled for cognitive environment, an important variable influencing language achievement and outcome. This case-control study applies the deconfounding principle by using a sibling as a control to investigate language outcomes in a male child 11 years after administration of ITC for ALL at the age of 2 years 3 months. A comprehensive behavioral language test battery failed to differentiate the siblings on current language performance when descriptively compared, but neurophysiological assessment revealed that the ITC-treated child required more time and elicited a smaller N400 component compared to his sibling during picture-word matching. The findings suggest that in the absence of pretreatment performance indices, comparison with sibling achievement may supplement what is known on posttreatment language skill development drawn from comparative studies using children matched on age, sex, and educational level drawn from the community. The study's findings offer pilot data of language outcomes following ITC beyond the early stage of survivorship. The benefits and limitations of using siblings in research where the cognitive environment is known to make an important contribution to skill development are discussed.

  15. On which timescales do gas transfer velocities control North Atlantic CO2 flux variability?

    Science.gov (United States)

    Couldrey, Matthew P.; Oliver, Kevin I. C.; Yool, Andrew; Halloran, Paul R.; Achterberg, Eric P.

    2016-05-01

    The North Atlantic is an important basin for the global ocean's uptake of anthropogenic and natural carbon dioxide (CO2), but the mechanisms controlling this carbon flux are not fully understood. The air-sea flux of CO2, F, is the product of a gas transfer velocity, k, the air-sea CO2 concentration gradient, ΔpCO2, and the temperature- and salinity-dependent solubility coefficient, α. k is difficult to constrain, representing the dominant uncertainty in F on short (instantaneous to interannual) timescales. Previous work shows that in the North Atlantic, ΔpCO2 and k both contribute significantly to interannual F variability but that k is unimportant for multidecadal variability. On some timescale between interannual and multidecadal, gas transfer velocity variability and its associated uncertainty become negligible. Here we quantify this critical timescale for the first time. Using an ocean model, we determine the importance of k, ΔpCO2, and α on a range of timescales. On interannual and shorter timescales, both ΔpCO2 and k are important controls on F. In contrast, pentadal to multidecadal North Atlantic flux variability is driven almost entirely by ΔpCO2; k contributes less than 25%. Finally, we explore how accurately one can estimate North Atlantic F without a knowledge of nonseasonal k variability, finding it possible for interannual and longer timescales. These findings suggest that continued efforts to better constrain gas transfer velocities are necessary to quantify interannual variability in the North Atlantic carbon sink. However, uncertainty in k variability is unlikely to limit the accuracy of estimates of longer-term flux variability.

  16. Robust Model Predictive Control of a Nonlinear System with Known Scheduling Variable and Uncertain Gain

    DEFF Research Database (Denmark)

    Mirzaei, Mahmood; Poulsen, Niels Kjølstad; Niemann, Hans Henrik

    2012-01-01

    Robust model predictive control (RMPC) of a class of nonlinear systems is considered in this paper. We will use Linear Parameter Varying (LPV) model of the nonlinear system. By taking the advantage of having future values of the scheduling variable, we will simplify state prediction. Because...... of the special structure of the problem, uncertainty is only in the B matrix (gain) of the state space model. Therefore by taking advantage of this structure, we formulate a tractable minimax optimization problem to solve robust model predictive control problem. Wind turbine is chosen as the case study and we...... choose wind speed as the scheduling variable. Wind speed is measurable ahead of the turbine, therefore the scheduling variable is known for the entire prediction horizon....

  17. Investigation on multi-variable decoupled temperature control system for enamelling machine with heated air circulation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yang; Qin, Le; Zou, Shipeng; Long, Shijun [School of Information Engineering, Guangdong University of Technology, Guangzhou, 510006 (China)

    2014-04-11

    A lots of problems may occur frequently when controlling the temperature of the enamelling machine oven in the real industrial process, such as multi-variable coupled problem. an experimental rig with triple inputs and triple outputs was devised and a simulation modeling was established accordingly in this study,. the temperature control system based on the feedforward compensation algorithm was proposed. Experimental results have shown that the system is of high efficiency, good stability and promising application.

  18. Active Power Filter DC Bus Voltage Piecewise Reaching Law Variable Structure Control

    OpenAIRE

    Liu, Baolian; Ding, Zujun; Zhao, Huanyu; Jin, Defei

    2014-01-01

    The DC bus voltage stability control is one key technology to ensure that Active Power Filter (APF) operates stably. The external disturbances such as power grid and load fluctuation and the system parameters changing may affect the stability of APF DC bus voltage and the normal operation of APF. The mathematical model of DC bus voltage is established according to power balance principle and a DC bus voltage piecewise reaching law variable structure control algorithm is proposed to solve the ...

  19. Heart Rate Variability as a Measure of Airport Ramp-Traffic Controllers Workload

    Science.gov (United States)

    Hayashi, Miwa; Dulchinos, Victoria Lee

    2016-01-01

    Heart Rate Variability (HRV) has been reported to reflect the person's cognitive and emotional stress levels, and may offer an objective measure of human-operator's workload levels, which are recorded continuously and unobtrusively to the task performance. The present paper compares the HRV data collected during a human-in-the-loop simulation of airport ramp-traffic control operations with the controller participants' own verbal self-reporting ratings of their workload.

  20. Perceived Social Support and Locus of Control as the Predictors of Vocational Outcome Expectations

    Science.gov (United States)

    Isik, Erkan

    2013-01-01

    The purpose of this study was to examine the relationships of vocational outcome expectation to social support which is an environmental factor and locus of control which is a personal factor. With this purpose, using Social Cognitive Career Theory as the theoretical framework, 263 undergraduate students completed Vocational Outcome Expectations…

  1. Cognitive Dysfunction, Locus of Control and Treatment Outcome among Chronic Alcoholics.

    Science.gov (United States)

    Abbott, Max W.

    While alcoholism is no longer regarded as a unitary disorder, conventional measures of congition and personality have yet to be shown capable of consistently predicting clinical outcomes. To investigate cognitive dysfunction and locus of control as predictors of post treatment outcome in a large sample of alcoholics, 106 alcoholics (74 men, 32…

  2. FUZZY LOGIC BASED INTELLIGENT CONTROL OF A VARIABLE SPEED CAGE MACHINE WIND GENERATION SYSTEM

    Science.gov (United States)

    The paper describes a variable-speed wind generation system where fuzzy logic principles are used to optimize efficiency and enhance performance control. A squirrel cage induction generator feeds the power to a double-sided pulse width modulated converter system which either pump...

  3. Physical activity, mindfulness meditation, or heart rate variability biofeedback for stress reduction: a randomized controlled trial

    NARCIS (Netherlands)

    van der Zwan, J.E.; de Vente, W.; Huizink, A.C.; Bögels, S.M.; de Bruin, E.I.

    2015-01-01

    In contemporary western societies stress is highly prevalent, therefore the need for stress-reducing methods is great. This randomized controlled trial compared the efficacy of self-help physical activity (PA), mindfulness meditation (MM), and heart rate variability biofeedback (HRV-BF) in reducing

  4. Wind tunnel experiments to prove a hydraulic passive torque control concept for variable speed wind turbines

    NARCIS (Netherlands)

    Diepeveen, N.F.B.; Jarquin-Laguna, A.

    2014-01-01

    In this paper the results are presented of experiments to prove an innovative concept for passive torque control of variable speed wind turbines using fluid power technology. It is demonstrated that by correctly configuring the hydraulic drive train, the wind turbine rotor operates at or near

  5. Integrated Variable Speed Limits Control and Ramp Metering for Bottleneck Regions on Freeway

    Directory of Open Access Journals (Sweden)

    Ming-hui Ma

    2015-01-01

    Full Text Available To enhance the efficiency of the existing freeway system and therefore to mitigate traffic congestion and related problems on the freeway mainline lane-drop bottleneck region, the advanced strategy for bottleneck control is essential. This paper proposes a method that integrates variable speed limits and ramp metering for freeway bottleneck region control to relieve the chaos in bottleneck region. To this end, based on the analyses of spatial-temporal patterns of traffic flow, a macroscopic traffic flow model is extended to describe the traffic flow operating characteristic by considering the impacts of variable speed limits in mainstream bottleneck region. In addition, to achieve the goal of balancing the priority of the vehicles on mainline and on-ramp, increasing capacity, and reducing travel delay on bottleneck region, an improved control model, as well as an advanced control strategy that integrates variable speed limits and ramp metering, is developed. The proposed method is tested in simulation for a real freeway infrastructure feed and calibrates real traffic variables. The results demonstrate that the proposed method can substantially improve the traffic flow efficiency of mainline and on-ramp and enhance the quality of traffic flow at the investigated freeway mainline bottleneck.

  6. Lyapunov-based constrained engine torque control using electronic throttle and variable cam timing

    NARCIS (Netherlands)

    Feru, E.; Lazar, M.; Gielen, R.H.; Kolmanovsky, I.V.; Di Cairano, S.

    2012-01-01

    In this paper, predictive control of a spark ignition engine equipped with an electronic throttle and a variable cam timing actuator is considered. The objective is to adjust the throttle angle and the engine cam timing in order to reduce the exhaust gas emissions while maintaining fast and

  7. Model-based servo hydraulic control of a continuously variable transmission

    NARCIS (Netherlands)

    Cools, S.J.M.; Veenhuizen, P.A.; Pauwelussen, J.P.

    2004-01-01

    In order to reduce the power consumption of a transmission, maximum tracking accuracy should be achieved of both ratio and pressures in the variator. A control strategy is proposed to steer a variator, actuated with a newly developed hydraulic system, of a Continuously Variable Transmission (CVT).

  8. Emotional variability during mother-adolescent conflict interactions: Longitudinal links to adolescent disclosure and maternal control

    NARCIS (Netherlands)

    Van der Giessen, D.; Branje, S.; Keijsers, L.; Van Lier, P.A.C.; Koot, H.M.; Meeus, W.

    2014-01-01

    The aim of this study was to examine relations of emotional variability during mother-adolescent conflict interactions in early adolescence with adolescent disclosure and maternal control in early and late adolescence. Data were used from 92 mother-adolescent dyads (M age T1 = 13.05; 65.20% boys)

  9. Using Statistical Process Control Charts to Study Stuttering Frequency Variability during a Single Day

    Science.gov (United States)

    Karimi, Hamid; O'Brian, Sue; Onslow, Mark; Jones, Mark; Menzies, Ross; Packman, Ann

    2013-01-01

    Purpose: Stuttering varies between and within speaking situations. In this study, the authors used statistical process control charts with 10 case studies to investigate variability of stuttering frequency. Method: Participants were 10 adults who stutter. The authors counted the percentage of syllables stuttered (%SS) for segments of their speech…

  10. Child predictors of learning to control variables via instruction or self-discovery

    NARCIS (Netherlands)

    Wagensveld, B.; Segers, P.C.J.; Kleemans, M.A.J.; Verhoeven, L.T.W.

    2015-01-01

    We examined the role child factors on the acquisition and transfer of learning the control of variables strategy (CVS) via instruction or self-discovery. Seventy-six fourth graders and 43 sixth graders were randomly assigned to a group receiving direct CVS instruction or a discovery learning group.

  11. Single motor–variable stiffness actuator using bistable switching mechanisms for independent motion and stiffness control

    NARCIS (Netherlands)

    Groothuis, Stefan; Carloni, Raffaella; Stramigioli, Stefano

    This paper presents a proof of concept of a variable stiffness actuator (VSA) that uses only one (high power) input motor. In general, VSAs use two (high power) motors to be able to control both the output position and the output stiffness, which possibly results in a heavy, and bulky system. In

  12. Speed control at low wind speeds for a variable speed fixed pitch wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Rosmin, N.; Watson, S.J.; Tompson, M. [Loughborough Univ., Loughborough, Leicestershire (United Kingdom)

    2010-03-09

    The maximum power regulation below rated wind speed is regulated by changing the rotor/generator speed at large frequency range in a fixed pitch, variable speed, stall-regulated wind turbine. In order to capture the power at a maximum value the power coefficient is kept at maximum peak point by maintaining the tip speed ratio at its optimum value. The wind industry is moving from stall regulated fixed speed wind turbines to newer improved innovative versions with better reliability. While a stall regulated fixed pitch wind turbine is among the most cost-effective wind turbine on the market, its problems include noise, severe vibrations, high thrust loads and low power efficiency. Therefore, in order to improve such drawbacks, the rotation of the generator speed is made flexible where the rotation can be controlled in variable speed. This paper discussed the development of a simulation model which represented the behaviour of a stall regulated variable speed wind turbine at low wind speed control region by using the closed loop scalar control with adjustable speed drive. The paper provided a description of each sub-model in the wind turbine system and described the scalar control of the induction machine. It was concluded that by using a constant voltage/frequency ratio of the generator's stator side control, the generator speed could be regulated and the generator torque could be controlled to ensure the power coefficient could be maintained close to its maximum value. 38 refs., 1 tab., 10 figs.

  13. Preliminary Study on Structural Optimization with Control Variables Using Equivalent Static Loads for Spring-damper Control Systems

    International Nuclear Information System (INIS)

    Yoo, Nam-sun; Jung, Ui-Jin; Park, Gyung-Jin; Kim, Tai-Kyung

    2014-01-01

    An optimization method is proposed for the simultaneous design of structural and control systems using the equivalent static loads. In the past researches, the control parameters of such feedback gains are obtained to improve some performance in the steady-state. However, the actuators which have position and velocity feedback gains should be designed to exhibit a good performance in the time domain. In other words, the system analysis should be conducted for the transient-state in dynamic manner. In this research, a new equivalent static loads method is presented to treat the control variables as the design variables. The equivalent static loads (ESLs) set is defined as a static load set which generates the same displacement field as that from dynamic loads at a certain time. The calculated sets of ESLs are applied as multiple loading conditions in the optimization process. Several examples are solved to validate the proposed method

  14. Intensive blood glucose control and vascular outcomes in patients with type 2 diabetes.

    NARCIS (Netherlands)

    Patel, A.; MacMahon, S; Chalmers, J.; Neal, B.; Billot, L.; Woodward, M.; Marre, M.; Cooper, M.; Glasziou, P.; Grobbee, D.E.; Hamet, P.; Harrap, S.; Heller, S.; Liu, L.; Mancia, G.; Mogensen, C.E.; Pan, C.; Poulter, N.; Rodgers, A.; Williams, B.; Bompoint, S.; Galan, B.E. de; Joshi, R.; Travert, F.

    2008-01-01

    BACKGROUND: In patients with type 2 diabetes, the effects of intensive glucose control on vascular outcomes remain uncertain. METHODS: We randomly assigned 11,140 patients with type 2 diabetes to undergo either standard glucose control or intensive glucose control, defined as the use of gliclazide

  15. 75 FR 30410 - Disease, Disability, and Injury Prevention and Control Special Interest Projects (SIPs): Outcomes...

    Science.gov (United States)

    2010-06-01

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention Disease, Disability, and Injury Prevention and Control Special Interest Projects (SIPs): Outcomes of Screening... 10(a)(2) of the Federal Advisory Committee Act (Pub. L. 92- 463), the Centers for Disease Control and...

  16. CHARACTERISTIC OF PARAMETERS OF HEART RATE VARIABILITY IN PATIENTS WITH DIFFICULT-TO-CONTROL AND CONTROLLED ARTERIAL HYPERTENSION

    OpenAIRE

    Tymoshenko O. S.; Yabluchansky M. I.; Martynenko O. V.

    2017-01-01

    Parameters of heart rate variability (HRV) were studied in 112 patients with arterial hypertension (AH) aged 58.5 ± 9 years (60 patients with difficult-to-control arterial hypertension (DTCAH) and 52 patients with controlled arterial hypertension (CAH)). The control group was consisted of 20 conditionally healthy persons of the same sex and age. It has been established that patients with AH were characterized by decrease in the level of total power of the HRV spectrum, the power of the high-f...

  17. The effect of COPD severity and study duration on exacerbation outcome in randomized controlled trials

    NARCIS (Netherlands)

    Eriksson, Goran; Calverley, Peter M.; Jenkins, Christine R.; Anzueto, Antonio R.; Make, Barry J.; Lindberg, Magnus; Fageras, Malin; Postma, Dirkje S.

    2017-01-01

    Background: When discontinuation in COPD randomized controlled trials (RCTs) is unevenly distributed between treatments (differential dropout), the capacity to demonstrate treatment effects may be reduced. We investigated the impact of the time of differential dropout on exacerbation outcomes in

  18. Sleep quality, the neglected outcome variable in clinical studies focusing on locomotor system; a construct validation study

    Directory of Open Access Journals (Sweden)

    Röder Christoph

    2010-09-01

    Full Text Available Abstract Background In addition to general health and pain, sleep is highly relevant to judging the well-being of an individual. Of these three important outcome variables, however, sleep is neglected in most outcome studies. Sleep is a very important resource for recovery from daily stresses and strains, and any alteration of sleep will likely affect mental and physical health, especially during disease. Sleep assessment therefore should be standard in all population-based or clinical studies focusing on the locomotor system. Yet current sleep assessment tools are either too long or too specific for general use. Methods Based on a literature review and subsequent patient-based rating of items, an expert panel designed a four-item questionnaire about sleep. Construct validation of the questionnaire in a random sample of the German-speaking Swiss population was performed in 2003. Reliability, correlation, and tests for internal consistency and validity were analyzed. Results Overall, 16,634 (70% out of 23,763 eligible individuals participated in the study. Test-retest reliability coefficients ranged from 0.72 to 0.87, and a Cronbach's alpha of 0.83 indicates good internal consistency. Results show a moderate to good correlation between sleep disturbances and health perception, and between sleep disturbances and overall pain. Conclusions The Sleep Standard Evaluation Questionnaire (SEQ-Sleep is a reliable and short tool with confirmed construct validity for sleep assessment in population-based observational studies. It is easy to administer and therefore suitable for postal surveys of the general population. Criterion validity remains to be determined.

  19. Variable versus conventional lung protective mechanical ventilation during open abdominal surgery: study protocol for a randomized controlled trial

    NARCIS (Netherlands)

    Spieth, Peter M.; Güldner, Andreas; Uhlig, Christopher; Bluth, Thomas; Kiss, Thomas; Schultz, Marcus J.; Pelosi, Paolo; Koch, Thea; Gama de Abreu, Marcelo

    2014-01-01

    General anesthesia usually requires mechanical ventilation, which is traditionally accomplished with constant tidal volumes in volume- or pressure-controlled modes. Experimental studies suggest that the use of variable tidal volumes (variable ventilation) recruits lung tissue, improves pulmonary

  20. Does the brain use sliding variables for the control of movements?

    Science.gov (United States)

    Hanneton, S; Berthoz, A; Droulez, J; Slotine, J J

    1997-12-01

    Delays in the transmission of sensory and motor information prevent errors from being instantaneously available to the central nervous system (CNS) and can reduce the stability of a closed-loop control strategy. On the other hand, the use of a pure feedforward control (inverse dynamics) requires a perfect knowledge of the dynamic behavior of the body and of manipulated objects. Sensory feedback is essential both to accommodate unexpected errors and events and to compensate for uncertainties about the dynamics of the body. Experimental observations concerning the control of posture, gaze and limbs have shown that the CNS certainly uses a combination of closed-loop and open-loop control. Feedforward components of movement, such as eye saccades, occur intermittently and present a stereotyped kinematic profile. In visuo-manual tracking tasks, hand movements exhibit velocity peaks that occur intermittently. When a delay or a slow dynamics are inserted in the visuo-manual control loop, intermittent step-and-hold movements appear clearly in the hand trajectory. In this study, we investigated strategies used by human subjects involved in the control of a particular dynamic system. We found strong evidence for substantial nonlinearities in the commands produced. The presence of step-and-hold movements seemed to be the major source of nonlinearities in the control loop. Furthermore, the stereotyped ballistic-like kinematics of these rapid and corrective movements suggests that they were produced in an open-loop way by the CNS. We analyzed the generation of ballistic movements in the light of sliding control theory assuming that they occurred when a sliding variable exceeded a constant threshold. In this framework, a sliding variable is defined as a composite variable (a combination of the instantaneous tracking error and its temporal derivatives) that fulfills a specific stability criterion. Based on this hypothesis and on the assumption of a constant reaction time, the

  1. Hierarchy of treatment variables affecting outcome of 131I therapy in thyroid cancer patients with lung metastases.

    Science.gov (United States)

    Kozak, Oksana V; Sukach, Georgiy G; Korchinskaya, Oksana I; Trembach, Alexander M; Turicina, Viktoria L; Voit, Natalia U

    2005-06-01

    To assess the correlations between the first 131I activity value, time interval between the courses of radioiodine treatment and the overall number of courses required for total destruction of lung metastases in patients with differentiated thyroid cancer with metastatic lesions in lungs. 27 patients with differentiated thyroid cancer with metastases in lungs have been treated with radioiodine after surgical intervention. Activities administered amounted from 1600 to 7980 MBq. The number of radioiodine courses before total ablation of all metastatic lesions amounted from 1 to 10. Time interval between the 1st and the 2nd courses amounted from 3.5 to 11.5 months (6 months in average). The regression analysis of the data has been made. The exponential model fits the actual number of courses as a function of the first-second activity value and time interval between the courses. The first activity has a decisive influence on the number of courses required for total metastases ablation. The greater was the first activity value, the lesser was the overall number of courses. Increasing time interval between 1st and 2nd courses to 10 months seems to result in reducing the number of courses. Nevertheless even in the case of high activities the probability to undergone less then 3 courses is low. According to the proposed model in thyroid cancer patients with metastases in lungs the first activity should be not lesser than 6000 MBq, time interval between treatments--approximately 10 months. The results of our study suggest that individual factors such as histology, the number and the size of metastases in lymph nodes could not contribute more to the final outcome than the treatment variables, namely the first-second activity and time interval, nor could they affect the hierarchy of the effects revealed for the treatment variables.

  2. Heart transplant outcomes in recipients of Centers for Disease Control (CDC) high risk donors.

    Science.gov (United States)

    Tsiouris, Athanasios; Wilson, Lynn; Sekar, Rajesh B; Mangi, Abeel A; Yun, James J

    2016-12-01

    A lack of donor hearts remains a major limitation of heart transplantation. Hearts from Centers for Disease Control (CDC) high-risk donors can be utilized with specific recipient consent. However, outcomes of heart transplantation with CDC high-risk donors are not well known. We sought to define outcomes, including posttransplant hepatitis and human immunodeficiency virus (HIV) status, in recipients of CDC high-risk donor hearts at our institution. All heart transplant recipients from August 2010 to December 2014 (n = 74) were reviewed. Comparison of 1) CDC high-risk donor (HRD) versus 2) standard-risk donor (SRD) groups were performed using chi-squared tests for nominal data and Wilcoxon two-sample tests for continuous variables. Survival was estimated with Kaplan-Meier curves. Of 74 heart transplant recipients reviewed, 66 (89%) received a SRD heart and eight (11%) received a CDC HRD heart. We found no significant differences in recipient age, sex, waiting list 1A status, pretransplant left ventricular assist device (LVAD) support, cytomegalovirus (CMV) status, and graft ischemia times (p = NS) between the HRD and SRD groups. All of the eight HRD were seronegative at the time of transplant. Postoperatively, there was no significant difference in rejection rates at six and 12 months posttransplant. Importantly, no HRD recipients acquired hepatitis or HIV. Survival in HRD versus SRD recipients was not significantly different by Kaplan-Meier analysis (log rank p = 0.644) at five years posttransplant. Heart transplants that were seronegative at the time of transplant had similar posttransplant graft function, rejection rates, and five-year posttransplant survival versus recipients of SRD hearts. At our institution, no cases of hepatitis or HIV occurred in HRD recipients in early follow-up. © 2016 Wiley Periodicals, Inc.

  3. Two-Degrees of Freedom and Variable Structure Controllers for Induction Motor Drives

    Directory of Open Access Journals (Sweden)

    ZAKY, M.

    2018-02-01

    Full Text Available This paper presents a two-degrees-of-Freedom (2DOF and variable structure control (VSC schemes for induction motor (IM drives. The designed VSC incorporates independent feedback and feedforward terms as 2DOF control principle. This structure improves the response of the proposed VSC under speed reference tracking and load disturbance changes. Stability of VSC using Lyapunov theory is discussed. Due to the variable nature of the switching function of VSC, two conditions to ensure Lyapunov stability candidate are derived based on the error signal. A design criterion for the parameters of VSC are introduced to guarantee the stability. The complete IM drive system with the proposed VSC controller is built using MATLAB/Simulink. A laboratory prototype is executed experimentally using DSP-DS1104 control board. All controllers are implemented practically. Simulation and experimental results are provided under different working conditions. Performance evaluation of classic control schemes and the proposed VSC approach is presented. The proposed VSC approach gives superior behavior under speed reference variations and torque disturbances. The disturbances using the proposed controller are strongly suppressed compared to classic 2DOF control scheme.

  4. Solving quantum optimal control problems using Clebsch variables and Lin constraints

    Science.gov (United States)

    Delgado-Téllez, M.; Ibort, A.; Rodríguez de la Peña, T.

    2018-01-01

    Clebsch variables (and Lin constraints) are applied to the study of a class of optimal control problems for affine-controlled quantum systems. The optimal control problem will be modelled with controls defined on an auxiliary space where the dynamical group of the system acts freely. The reciprocity between both theories: the classical theory defined by the objective functional and the quantum system, is established by using a suitable version of Lagrange’s multipliers theorem and a geometrical interpretation of the constraints of the system as defining a subspace of horizontal curves in an associated bundle. It is shown how the solutions of the variational problem defined by the objective functional determine solutions of the quantum problem. Then a new way of obtaining explicit solutions for a family of optimal control problems for affine-controlled quantum systems (finite or infinite dimensional) is obtained. One of its main advantages, is the the use of Clebsch variables allows to compute such solutions from solutions of invariant problems that can often be computed explicitly. This procedure can be presented as an algorithm that can be applied to a large class of systems. Finally, some simple examples, spin control, a simple quantum Hamiltonian with an ‘Elroy beanie’ type classical model and a controlled one-dimensional quantum harmonic oscillator, illustrating the main features of the theory, will be discussed.

  5. Autonomous and controlled motivation for eating disorders treatment: baseline predictors and relationship to treatment outcome.

    Science.gov (United States)

    Carter, Jacqueline C; Kelly, Allison C

    2015-03-01

    This study aimed to identify baseline predictors of autonomous and controlled motivation for treatment (ACMT) in a transdiagnostic eating disorder sample, and to examine whether ACMT at baseline predicted change in eating disorder psychopathology during treatment. Participants were 97 individuals who met DSM-IV-TR criteria for an eating disorder and were admitted to a specialized intensive treatment programme. Self-report measures of eating disorder psychopathology, ACMT, and various psychosocial variables were completed at the start of treatment. A subset of these measures was completed again after 3, 6, 9, and 12 weeks of treatment. Multiple regression analyses showed that baseline autonomous motivation was higher among patients who reported more self-compassion and more received social support, whereas the only baseline predictor of controlled motivation was shame. Multilevel modelling revealed that higher baseline autonomous motivation predicted faster decreases in global eating disorder psychopathology, whereas the level of controlled motivation at baseline did not. The current findings suggest that developing interventions designed to foster autonomous motivation specifically and employing autonomy supportive strategies may be important to improving eating disorders treatment outcome. The findings of this study suggest that developing motivational interventions that focus specifically on enhancing autonomous motivation for change may be important for promoting eating disorder recovery. Our results lend support for the use of autonomy supportive strategies to strengthen personally meaningful reasons to achieve freely chosen change goals in order to enhance treatment for eating disorders. One study limitation is that there were no follow-up assessments beyond the 12-week study and we therefore do not know whether the relationships that we observed persisted after treatment. Another limitation is that this was a correlational study and it is therefore important

  6. Variable cycle control model for intersection based on multi-source information

    Science.gov (United States)

    Sun, Zhi-Yuan; Li, Yue; Qu, Wen-Cong; Chen, Yan-Yan

    2018-05-01

    In order to improve the efficiency of traffic control system in the era of big data, a new variable cycle control model based on multi-source information is presented for intersection in this paper. Firstly, with consideration of multi-source information, a unified framework based on cyber-physical system is proposed. Secondly, taking into account the variable length of cell, hysteresis phenomenon of traffic flow and the characteristics of lane group, a Lane group-based Cell Transmission Model is established to describe the physical properties of traffic flow under different traffic signal control schemes. Thirdly, the variable cycle control problem is abstracted into a bi-level programming model. The upper level model is put forward for cycle length optimization considering traffic capacity and delay. The lower level model is a dynamic signal control decision model based on fairness analysis. Then, a Hybrid Intelligent Optimization Algorithm is raised to solve the proposed model. Finally, a case study shows the efficiency and applicability of the proposed model and algorithm.

  7. Modelling and control algorithms of the cross conveyors line with multiengine variable speed drives

    Science.gov (United States)

    Cheremushkina, M. S.; Baburin, S. V.

    2017-02-01

    The paper deals with the actual problem of developing the control algorithm that meets the technical requirements of the mine belt conveyors, and enables energy and resource savings taking into account a random sort of traffic. The most effective method of solution of these tasks is the construction of control systems with the use of variable speed drives for asynchronous motors. The authors designed the mathematical model of the system ‘variable speed multiengine drive - conveyor - control system of conveyors’ that takes into account the dynamic processes occurring in the elements of the transport system, provides an assessment of the energy efficiency of application the developed algorithms, which allows one to reduce the dynamic overload in the belt to 15-20%.

  8. Stiffness Control of Variable Serial Elastic Actuators: Energy Efficiency through Exploitation of Natural Dynamics

    Directory of Open Access Journals (Sweden)

    Philipp Beckerle

    2017-09-01

    Full Text Available Variable elastic actuators are very promising for applications in physical human–robot interaction. Besides enabling human safety, such actuators can support energy efficiency, especially if the natural behavior of the system is exploited. In this paper, the power and energy consumption of variable stiffness actuators with serial elasticity is investigated analytically and experimentally. Besides the fundamental mechanics, the influence of friction and electrical losses is discussed. A simple but effective stiffness control method is used to exploit the corresponding knowledge of natural dynamics by tuning the system to antiresonance operation. Despite nonlinear friction effects and additional electrical dynamics, the consideration of the ideal mechanical dynamics is completely sufficient for stiffness control. Simulations and experiments show that this yields a distinct reduction in power and energy consumption, which underlines the suitability of the control strategy.

  9. Power Maximization Control of Variable Speed Wind Generation System Using Permanent Magnet Synchronous Generator

    Science.gov (United States)

    Morimoto, Shigeo; Nakamura, Tomohiko; Takeda, Yoji

    This paper proposes the sensorless output power maximization control of the wind generation system. A permanent magnet synchronous generator (PMSG) is used as a variable speed generator in the proposed system. The generator torque is suitably controlled according to the generator speed and thus the power from a wind turbine settles down on the maximum power point by the proposed MPPT control method, where the information of wind velocity is not required. Moreover, the maximum available generated power is obtained by the optimum current vector control. The current vector of PMSG is optimally controlled according to the generator speed and the required torque in order to minimize the losses of PMSG considering the voltage and current constraints. The proposed wind power generation system can be achieved without mechanical sensors such as a wind velocity detector and a position sensor. Several experimental results show the effectiveness of the proposed control method.

  10. Capacitor regenerative braking system of electric wheelchair for senior citizen based on variable frequency chopper control.

    Science.gov (United States)

    Takahashi, Yoshiaki; Seki, Hirokazu

    2009-01-01

    This paper proposes a novel regenerative braking control system of electric wheelchairs for senior citizen. "Electric powered wheelchair", which generates the driving force by electric motors according to the human operation, is expected to be widely used as a mobility support system for elderly people. This study focuses on the braking control to realize the safety and smooth stopping motion using the regenerative braking control technique based on fuzzy algorithm. The ride quality improvement and energy recycling can be expected by the proposed control system with stopping distance estimation and variable frequency control on the step-up/down chopper type of capacitor regenerative circuit. Some driving experiments confirm the effectiveness of the proposed control system.

  11. Chaos Synchronization Using Adaptive Dynamic Neural Network Controller with Variable Learning Rates

    Directory of Open Access Journals (Sweden)

    Chih-Hong Kao

    2011-01-01

    Full Text Available This paper addresses the synchronization of chaotic gyros with unknown parameters and external disturbance via an adaptive dynamic neural network control (ADNNC system. The proposed ADNNC system is composed of a neural controller and a smooth compensator. The neural controller uses a dynamic RBF (DRBF network to online approximate an ideal controller. The DRBF network can create new hidden neurons online if the input data falls outside the hidden layer and prune the insignificant hidden neurons online if the hidden neuron is inappropriate. The smooth compensator is designed to compensate for the approximation error between the neural controller and the ideal controller. Moreover, the variable learning rates of the parameter adaptation laws are derived based on a discrete-type Lyapunov function to speed up the convergence rate of the tracking error. Finally, the simulation results which verified the chaotic behavior of two nonlinear identical chaotic gyros can be synchronized using the proposed ADNNC scheme.

  12. Synergies in the space of control variables within the equilibrium-point hypothesis.

    Science.gov (United States)

    Ambike, S; Mattos, D; Zatsiorsky, V M; Latash, M L

    2016-02-19

    We use an approach rooted in the recent theory of synergies to analyze possible co-variation between two hypothetical control variables involved in finger force production based on the equilibrium-point (EP) hypothesis. These control variables are the referent coordinate (R) and apparent stiffness (C) of the finger. We tested a hypothesis that inter-trial co-variation in the {R; C} space during repeated, accurate force production trials stabilizes the fingertip force. This was expected to correspond to a relatively low amount of inter-trial variability affecting force and a high amount of variability keeping the force unchanged. We used the "inverse piano" apparatus to apply small and smooth positional perturbations to fingers during force production tasks. Across trials, R and C showed strong co-variation with the data points lying close to a hyperbolic curve. Hyperbolic regressions accounted for over 99% of the variance in the {R; C} space. Another analysis was conducted by randomizing the original {R; C} data sets and creating surrogate data sets that were then used to compute predicted force values. The surrogate sets always showed much higher force variance compared to the actual data, thus reinforcing the conclusion that finger force control was organized in the {R; C} space, as predicted by the EP hypothesis, and involved co-variation in that space stabilizing total force. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  13. Control system and method for a power delivery system having a continuously variable ratio transmission

    Science.gov (United States)

    Frank, Andrew A.

    1984-01-01

    A control system and method for a power delivery system, such as in an automotive vehicle, having an engine coupled to a continuously variable ratio transmission (CVT). Totally independent control of engine and transmission enable the engine to precisely follow a desired operating characteristic, such as the ideal operating line for minimum fuel consumption. CVT ratio is controlled as a function of commanded power or torque and measured load, while engine fuel requirements (e.g., throttle position) are strictly a function of measured engine speed. Fuel requirements are therefore precisely adjusted in accordance with the ideal characteristic for any load placed on the engine.

  14. Power Control of Permanent Magnet Generator Based Variable Speed Wind Turbines

    DEFF Research Database (Denmark)

    Deng, Fujin; Chen, Zhe

    2009-01-01

    When the wind power accounts for a large portion of the grid, it will be required to regulate the active power and reactive power. This paper investigates a MWlevel variable speed wind turbine with a permanent magnet synchronous generator (PMSG). The power control capabilities of two kinds...... of control schemes conducted respectively on this wind turbine under two conditions, including rapid wind speed change and grids faults, are compared. The simulation study of the wind turbine system is conducted using PSCAD/EMTDC, and the results show the different power control capabilities of the two...

  15. Technical specifications of variable speed motors for negative pressure control in hot cell area

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seon Duk; Bang, H. S.; Cho, W. K

    2002-01-01

    Hot cells are the facilities for handling the high radioactive materials and various R and D activities are performed using hot cells. Therefore the control of air flow in hot cell area is very important technology and it is started with the variable speed motor(VSM) controlling the air handling system in that area. This report describes various technical aspects of VS motors and will be useful for understanding the practical technologies of VS motors and also for optimization of the negative pressure controls in hot cell area.

  16. Dysglycemia, Glycemic Variability, and Outcome After Cardiac Arrest and Temperature Management at 33°C and 36°C

    DEFF Research Database (Denmark)

    Borgquist, Ola; Wise, Matt P; Nielsen, Niklas

    2017-01-01

    OBJECTIVES: Dysglycemia and glycemic variability are associated with poor outcomes in critically ill patients. Targeted temperature management alters blood glucose homeostasis. We investigated the association between blood glucose concentrations and glycemic variability and the neurologic outcomes...... of patients randomized to targeted temperature management at 33°C or 36°C after cardiac arrest. DESIGN: Post hoc analysis of the multicenter TTM-trial. Primary outcome of this analysis was neurologic outcome after 6 months, referred to as "Cerebral Performance Category." SETTING: Thirty-six sites in Europe...... and Australia. PATIENTS: All 939 patients with out-of-hospital cardiac arrest of presumed cardiac cause that had been included in the TTM-trial. INTERVENTIONS: Targeted temperature management at 33°C or 36°C. MEASUREMENTS AND MAIN RESULTS: Nonparametric tests as well as multiple logistic regression and mixed...

  17. The significance of clinical experience on learning outcome from resuscitation training-a randomised controlled study

    DEFF Research Database (Denmark)

    Jensen, Morten Lind; Lippert, Freddy; Hesselfeldt, Rasmus

    2008-01-01

    CONTEXT: The impact of clinical experience on learning outcome from a resuscitation course has not been systematically investigated. AIM: To determine whether half a year of clinical experience before participation in an Advanced Life Support (ALS) course increases the immediate learning outcome...... and retention of learning. MATERIALS AND METHODS: This was a prospective single blinded randomised controlled study of the learning outcome from a standard ALS course on a volunteer sample of the entire cohort of newly graduated doctors from Copenhagen University. The outcome measurement was ALS...... immediately following graduation. RESULTS: Invitation to participate was accepted by 154/240 (64%) graduates and 117/154 (76%) completed the study. There was no difference between the intervention and control groups with regard to the immediate learning outcome. The intervention group had significantly higher...

  18. Gender discrepancies in the outcomes of schedule control on overtime hours and income in Germany

    OpenAIRE

    Lott, Yvonne; Chung, Heejung

    2016-01-01

    Schedule control can have both positive – e.g., increased income – but also negative outcomes – e.g., increased overtime. Here our core interest is whether there are gender discrepancies in these outcomes. Given the different ways in which schedule control can be used, and perceived to be used by men and women, their outcomes are also expected to be different. This is examined using the German Socio-Economic Panel Study (2003-2011), and panel regression models. The results show that schedule ...

  19. Temporal Variability of Canopy Light Use Efficiency and its Environmental Controls in a Subtropical Mangrove Wetland

    Science.gov (United States)

    Zhu, X.

    2016-12-01

    Mangrove wetlands play an important role in global carbon cycle due to their strong carbon sequestration resulting from high plant carbon assimilation and low soil respiration. However, temporal variability of carbon sequestration in mangrove wetlands is less understood since carbon processes of mangrove wetlands are influenced by many complicated and concurrent environmental controls including tidal activities, site climate and soil conditions. Canopy light use efficiency (LUE), is the most important plant physiological parameter that can be used to describe the temporal dynamics of canopy photosynthesis, and therefore a better characterization of temporal variability of canopy LUE will improve our understanding in mangrove photosynthesis and carbon balance. One of our aims is to study the temporal variability of canopy LUE and its environmental controls in a subtropical mangrove wetland. Half-hourly canopy LUE is derived from eddy covariance (EC) carbon flux and photosynthesis active radiation observations, and half-hourly environmental controls we measure include temperature, humidity, precipitation, radiation, tidal height, salinity, etc. Another aim is to explore the links between canopy LUE and spectral indices derived from near-surface tower-based remote sensing (normalized difference vegetation index, enhanced vegetation index, photochemical reflectance index, solar-induced chlorophyll fluorescence, etc.), and then identify potential quantitative relationships for developing remote sensing-based estimation methods of canopy LUE. At present, some instruments in our in-situ observation system have not yet been installed (planned in next months) and therefore we don't have enough measurements to support our analysis. However, a preliminary analysis of our historical EC and climate observations in past several years indicates that canopy LUE shows strong temporal variability and is greatly affected by environmental factors such as tidal activity. Detailed and

  20. High Intrapatient Variability of Tacrolimus Exposure in the Early Period After Liver Transplantation Is Associated With Poorer Outcomes.

    Science.gov (United States)

    Rayar, Michel; Tron, Camille; Jézéquel, Caroline; Beaurepaire, Jean Marie; Petitcollin, Antoine; Houssel-Debry, Pauline; Camus, Christophe; Verdier, Marie Clémence; Dehlawi, Ammar; Lakéhal, Mohamed; Desfourneaux, Véronique; Meunier, Bernard; Sulpice, Laurent; Bellissant, Eric; Boudjema, Karim; Lemaitre, Florian

    2018-03-01

    Tacrolimus (TAC) is the cornerstone of immunosuppressive regimen in liver transplantation (LT). Its pharmacokinetics is characterized by a high interpatient and intrapatient variability (IPV) leading to an unpredictable dose-response relationship. The aim of our study was to evaluate the impact of TAC IPV (IPV) on graft and patient outcomes after LT. We retrospectively analyzed 812 LT recipients treated with TAC. The IPV of TAC concentrations was estimated by calculating the coefficient of variation (CV) of whole blood trough concentrations. Patients were categorized in 2 groups: low IPV (CV < 40%) and high IPV (CV ≥ 40%). There were significantly more neurologic complications (31.2% vs 16.6%, P < 0.001), cardiovascular complications (19.7% vs 9.7%, P < 0.001), and acute renal failure requiring dialysis (8.5% vs 2.2%, P < 0.001) in the high CV group than in the low CV group. Moreover, graft survival was significantly poorer in the high CV group (hazard ratio, 1.42; 95% confidence interval, 1.04-1.95; P = 0.03). A pretransplantation elevated Model for End-Stage Liver Disease score (P < 0.001) and Child-Pugh grade (P < 0.001) were identified as risk factors for presenting a high CV. A high CV of TAC concentrations was found to be predictive of TAC-related toxicity and poorer survival.

  1. Health locus of control in patients undergoing coronary artery surgery - changes and associated outcomes: a seven-year cohort study.

    Science.gov (United States)

    Rideout, Andrew; Tolmie, Elizabeth; Lindsay, Grace

    2017-01-01

    Health locus of control is a measure of an individual's beliefs in factors that are thought to determine health experiences. Scores are generated and form a graduated linear scale from external to internal control, with respect to their views on health causality. Health locus of control has been considered to be a relatively stable entity. However, it is not clear if this status changes in the advent of serious health challenges, such as coronary artery bypass graft surgery. The aim of this study is to explore the variability of health locus of control and its association with postoperative health in this context. In a longitudinal cohort study of patients undergoing coronary artery bypass graft surgery, a purposive sample ( n=215) were recruited from the waiting list and followed up postoperatively, at approximately one year and seven years later. Patients undergoing coronary artery bypass graft surgery demonstrated marked fluctuations in health locus of control in their peri-operative and rehabilitative phases. Mean health locus of control became more external (often associated with poorer outcomes) peri-operatively, and more internal (generally associated with better health outcomes) in the rehabilitative period. Health locus of control scores were shown to be changeable during a major health care intervention, with possible consequences for patient outcomes and care needs. The significant health belief upheaval demonstrated in this cohort should be considered in assessing patients preoperatively, and managed as part of the patients' clinical journey by both acute and rehabilitation staff. It is likely to have particular importance in individualised assessment and management of future prevention advice for patients.

  2. Optimal speech motor control and token-to-token variability: a Bayesian modeling approach.

    Science.gov (United States)

    Patri, Jean-François; Diard, Julien; Perrier, Pascal

    2015-12-01

    The remarkable capacity of the speech motor system to adapt to various speech conditions is due to an excess of degrees of freedom, which enables producing similar acoustical properties with different sets of control strategies. To explain how the central nervous system selects one of the possible strategies, a common approach, in line with optimal motor control theories, is to model speech motor planning as the solution of an optimality problem based on cost functions. Despite the success of this approach, one of its drawbacks is the intrinsic contradiction between the concept of optimality and the observed experimental intra-speaker token-to-token variability. The present paper proposes an alternative approach by formulating feedforward optimal control in a probabilistic Bayesian modeling framework. This is illustrated by controlling a biomechanical model of the vocal tract for speech production and by comparing it with an existing optimal control model (GEPPETO). The essential elements of this optimal control model are presented first. From them the Bayesian model is constructed in a progressive way. Performance of the Bayesian model is evaluated based on computer simulations and compared to the optimal control model. This approach is shown to be appropriate for solving the speech planning problem while accounting for variability in a principled way.

  3. Selection of controlled variables in bioprocesses. Application to a SHARON-Anammox process for autotrophic nitrogen removal

    DEFF Research Database (Denmark)

    Mauricio Iglesias, Miguel; Valverde Perez, Borja; Sin, Gürkan

    Selecting the right controlled variables in a bioprocess is challenging since the objectives of the process (yields, product or substrate concentration) are difficult to relate with a given actuator. We apply here process control tools that can be used to assist in the selection of controlled var...... variables to the case of the SHARON-Anammox process for autotrophic nitrogen removal....

  4. Adolescent and parent motivation for change affects psychotherapy outcomes among youth with poorly controlled diabetes.

    Science.gov (United States)

    Ellis, Deborah A; Berio, Heidi; Carcone, April Idalski; Naar-King, Sylvie

    2012-01-01

    Investigate effect of baseline motivation for change on treatment fidelity, therapeutic alliance, treatment dose, and treatment outcome in a randomized controlled trial of family therapy for youth with poorly controlled diabetes. Seventy-four adolescents and caregivers completed measures of motivation for change. Measures of fidelity, alliance, dose, and youth health status were collected. Structural equation modeling was used to test the direct and indirect effects of motivation on treatment outcomes. Parent motivation was significantly related to alliance and fidelity. Only alliance was significantly related to posttreatment metabolic control. In adolescent models, only motivation was significantly related to alliance. In both models, motivation had a significant indirect effect on metabolic control through alliance. Findings demonstrate the importance of parent and youth initial motivational status and treatment alliance to treatment outcome among youth with poorly controlled diabetes. Additional research on treatment techniques that promote motivation for change is needed.

  5. Variable structure TITO fuzzy-logic controller implementation for a solar air-conditioning system

    Energy Technology Data Exchange (ETDEWEB)

    Lygouras, J.N.; Pachidis, Th. [Laboratory of Electronics, School of Electrical and Computer Engineering, Democritus University of Thrace, GR-67100 Xanthi (Greece); Kodogiannis, V.S. [Centre for Systems Analysis, School of Computer Science, University of Westminster, London HA1 3TP (United Kingdom); Tarchanidis, K.N. [Department of Petroleum Technology, Technological Education Institute of Kavala, GR-65404, Kavala (Greece); Koukourlis, C.S. [Laboratory of Telecommunications, School of Electrical and Computer Engineering, Democritus University of Thrace, GR-67100 Xanthi (Greece)

    2008-04-15

    The design and implementation of a Two-Input/Two-Output (TITO) variable structure fuzzy-logic controller for a solar-powered air-conditioning system is described in this paper. Two DC motors are used to drive the generator pump and the feed pump of the solar air-conditioner. The first affects the temperature in the generator of the solar air-conditioner, while the second, the pressure in the power loop. The difficulty of Multi-Input/Multi-Output (MIMO) systems control is how to overcome the coupling effects among each degree of freedom. First, a traditional fuzzy-controller has been designed, its output being one of the components of the control signal for each DC motor driver. Secondly, according to the characteristics of the system's dynamics coupling, an appropriate coupling fuzzy-controller (CFC) is incorporated into a traditional fuzzy-controller (TFC) to compensate for the dynamic coupling among each degree of freedom. This control strategy simplifies the implementation problem of fuzzy control, but can also improve the control performance. This mixed fuzzy controller (MFC) can effectively improve the coupling effects of the systems, and this control strategy is easy to design and implement. Experimental results from the implemented system are presented. (author)

  6. Choice of the control variables of an isolated intersection by graph colouring

    Directory of Open Access Journals (Sweden)

    Batanović Vladan

    2015-01-01

    Full Text Available This paper deals with the problem of grouping the traffic streams into some groups - signal groups on a signalized intersection. The fact that more traffic streams, which are not in a conflict, can be controlled by one sequence of traffic lights means that one control variable can be assigned to one signal group. Determination of the complete sets of signal groups, i.e. the groups of traffic streams on one intersection, controlled by one control variable is defined in this paper as a graphcoloring problem. The complete sets of signal groups are obtained by coloring the complement of the graph of identical indications. It is shown that the minimal number of signal groups in the complete set of signal groups is equal to the chromatic number of the complement of the graph with identical indications. The problem of finding all complete sets of signal groups with minimal cardinality, which is equal to the chromatic number, is formulated as a linear programming problem where the values of variables belong to set {0,1}.

  7. Linking Inflammation, Cardiorespiratory Variability, and Neural Control in Acute Inflammation via Computational Modeling.

    Science.gov (United States)

    Dick, Thomas E; Molkov, Yaroslav I; Nieman, Gary; Hsieh, Yee-Hsee; Jacono, Frank J; Doyle, John; Scheff, Jeremy D; Calvano, Steve E; Androulakis, Ioannis P; An, Gary; Vodovotz, Yoram

    2012-01-01

    Acute inflammation leads to organ failure by engaging catastrophic feedback loops in which stressed tissue evokes an inflammatory response and, in turn, inflammation damages tissue. Manifestations of this maladaptive inflammatory response include cardio-respiratory dysfunction that may be reflected in reduced heart rate and ventilatory pattern variabilities. We have developed signal-processing algorithms that quantify non-linear deterministic characteristics of variability in biologic signals. Now, coalescing under the aegis of the NIH Computational Biology Program and the Society for Complexity in Acute Illness, two research teams performed iterative experiments and computational modeling on inflammation and cardio-pulmonary dysfunction in sepsis as well as on neural control of respiration and ventilatory pattern variability. These teams, with additional collaborators, have recently formed a multi-institutional, interdisciplinary consortium, whose goal is to delineate the fundamental interrelationship between the inflammatory response and physiologic variability. Multi-scale mathematical modeling and complementary physiological experiments will provide insight into autonomic neural mechanisms that may modulate the inflammatory response to sepsis and simultaneously reduce heart rate and ventilatory pattern variabilities associated with sepsis. This approach integrates computational models of neural control of breathing and cardio-respiratory coupling with models that combine inflammation, cardiovascular function, and heart rate variability. The resulting integrated model will provide mechanistic explanations for the phenomena of respiratory sinus-arrhythmia and cardio-ventilatory coupling observed under normal conditions, and the loss of these properties during sepsis. This approach holds the potential of modeling cross-scale physiological interactions to improve both basic knowledge and clinical management of acute inflammatory diseases such as sepsis and trauma.

  8. A switched energy saving position controller for variable-pressure electro-hydraulic servo systems.

    Science.gov (United States)

    Tivay, Ali; Zareinejad, Mohammad; Rezaei, S Mehdi; Baghestan, Keivan

    2014-07-01

    The electro-hydraulic servo system (EHSS) demonstrates a relatively low level of efficiency compared to other available actuation methods. The objective of this paper is to increase this efficiency by introducing a variable supply pressure into the system and controlling this pressure during the task of position tracking. For this purpose, an EHSS structure with controllable supply pressure is proposed and its dynamic model is derived from the basic laws of physics. A switching control structure is then proposed to control both the supply pressure and the cylinder position at the same time, in a way that reduces the overall energy consumption of the system. The stability of the proposed switching control system is guaranteed by proof, and its performance is verified by experimental testing. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  9. Modeling, Control, and Numerical Simulations of a Novel Binary-Controlled Variable Stiffness Actuator (BcVSA

    Directory of Open Access Journals (Sweden)

    Irfan Hussain

    2018-06-01

    Full Text Available This research work aims at realizing a new compliant robotic actuator for safe human-robotic interaction. In this paper, we present the modeling, control, and numerical simulations of a novel Binary-Controlled Variable Stiffness Actuator (BcVSA aiming to be used for the development of a novel compliant robotic manipulator. BcVSA is the proof of concept of the active revolute joint with the variable recruitment of series-parallel elastic elements. We briefly recall the basic design principle which is based on a stiffness varying mechanism consisting of a motor, three inline clutches, and three torsional springs with stiffness values (K0, 2K0, 4K0 connected to the load shaft and the motor shaft through two planetary sun gear trains with ratios (4:1, 4:1 respectively. We present the design concept, stiffness and dynamic modeling, and control of our BcVSA. We implemented three kinds of Multiple Model Predictive Control (MPC to control our actuator. The main motivation of choosing this controller lies in the fact that working principle of multiple MPC and multiple states space representation (stiffness level of our actuator share similar interests. In particular, we implemented Multiple MPC, Multiple Explicit MPC, and Approximated Multiple Explicit MPC. Numerical simulations are performed in order to evaluate their effectiveness for the future experiments on the prototype of our actuator. The simulation results showed that the Multiple MPC, and the Multiple Explicit MPC have similar results from the robustness point of view. On the other hand, the robustness performance of Approximated Multiple Explicit MPC is not good as compared to other controllers but it works in the offline framework while having the capability to compute the sub-optimal results. We also performed the comparison of MPC based controllers with the Computed Torque Control (CTC, and Linear Quadratic Regulator (LQR. In future, we are planning to test the presented approach on the

  10. Control of a Stand-Alone Variable Speed Wind Energy Supply System †

    Directory of Open Access Journals (Sweden)

    Mohamed M. Hamada

    2013-04-01

    Full Text Available This paper presents a simple control strategy for the operation of a variable speed stand-alone wind turbine with a permanent magnet synchronous generator (PMSG. The PMSG is connected to a three phase resistive load through a switch mode rectifier and a voltage source inverter. Control of the generator side converter is used to achieve maximum power extraction from the available wind power. Control of the DC-DC bidirectional buck-boost converter, which is connected between batteries bank and DC-link voltage, is used to maintain the DC-link voltage at a constant value. It is also used to make the batteries bank stores the surplus of wind energy and supplies this energy to the load during a wind power shortage. The load side voltage source inverter uses a relatively complex vector control scheme to control the output load voltage in terms of amplitude and frequency. The control strategy works under wind speed variation as well as with variable load. Extensive simulation results have been performed using MATLAB/SIMULINK.

  11. Internal versus external controls on age variability: Definitions, origins and implications in a changing climate

    Science.gov (United States)

    Harman, C. J.

    2015-12-01

    The unsteadiness of stream water age is now well established, but the controls on the age dynamics, and the adequate representation and prediction of those dynamics, are not. A basic distinction can be made between internal variability that arises from changes in the proportions of flow moving through the diverse flow pathways of a hydrologic system, and external variability that arises from the stochasticity of inputs and outputs (such as precipitation and streamflow). In this talk I will show how these two types of age variability can be formally defined and distinguished within the framework of rank StorAge Selection (rSAS) functions. Internal variability implies variations in time in the rSAS function, while external variability does not. This leads naturally to the definition of several modes of internal variability, reflecting generic ways that system flowpaths may be rearranged. This rearrangement may be induced by fluctuations in the system state (such as catchment wetness), or by longer-term changes in catchment structure (such as land use change). One type of change, the 'inverse storage effect' is characterized by an increase in the release of young water from the system in response to an increase in overall system storage. This effect can be seen in many hydrologic settings, and has important implications for the effect of altered hydroclimatic conditions on solute transport through a landscape. External variability, such as increased precipitation, can induce a decrease in mean transit time (and vice versa), but this effect is greatly enhanced if accompanied by an internal shift in flow pathways that increases the relative importance of younger water. These effects will be illustrated using data from field and experimental studies.

  12. Adaptive Synchronization of Fractional Order Complex-Variable Dynamical Networks via Pinning Control

    Science.gov (United States)

    Ding, Da-Wei; Yan, Jie; Wang, Nian; Liang, Dong

    2017-09-01

    In this paper, the synchronization of fractional order complex-variable dynamical networks is studied using an adaptive pinning control strategy based on close center degree. Some effective criteria for global synchronization of fractional order complex-variable dynamical networks are derived based on the Lyapunov stability theory. From the theoretical analysis, one concludes that under appropriate conditions, the complex-variable dynamical networks can realize the global synchronization by using the proper adaptive pinning control method. Meanwhile, we succeed in solving the problem about how much coupling strength should be applied to ensure the synchronization of the fractional order complex networks. Therefore, compared with the existing results, the synchronization method in this paper is more general and convenient. This result extends the synchronization condition of the real-variable dynamical networks to the complex-valued field, which makes our research more practical. Finally, two simulation examples show that the derived theoretical results are valid and the proposed adaptive pinning method is effective. Supported by National Natural Science Foundation of China under Grant No. 61201227, National Natural Science Foundation of China Guangdong Joint Fund under Grant No. U1201255, the Natural Science Foundation of Anhui Province under Grant No. 1208085MF93, 211 Innovation Team of Anhui University under Grant Nos. KJTD007A and KJTD001B, and also supported by Chinese Scholarship Council

  13. A Method of MPPT Control Based on Power Variable Step-size in Photovoltaic Converter System

    Directory of Open Access Journals (Sweden)

    Xu Hui-xiang

    2016-01-01

    Full Text Available Since the disadvantage of traditional MPPT algorithms of variable step-size, proposed power tracking based on variable step-size with the advantage method of the constant-voltage and the perturb-observe (P&O[1-3]. The control strategy modify the problem of voltage fluctuation caused by perturb-observe method, at the same time, introducing the advantage of constant-voltage method and simplify the circuit topology. With the theoretical derivation, control the output power of photovoltaic modules to change the duty cycle of main switch. Achieve the maximum power stabilization output, reduce the volatility of energy loss effectively, and improve the inversion efficiency[3,4]. Given the result of experimental test based theoretical derivation and the curve of MPPT when the prototype work.

  14. Flicker Mitigation by Individual Pitch Control of Variable Speed Wind Turbines With DFIG

    DEFF Research Database (Denmark)

    Zhang, Yunqian; Chen, Zhe; Hu, Weihao

    2014-01-01

    generatorto investigate the flicker emission and mitigation issues. An individual pitch control (IPC) strategy is proposed to reduce the flicker emission at different wind speed conditions. The IPC scheme is proposed and the individual pitch controller is designed according to the generator active power...... and the azimuth angle of the wind turbine. The simulations are performed on the NREL (National Renewable Energy Laboratory) 1.5-MW upwind reference wind turbine model. Simulation results show that damping the generator active power by IPC is an effective means for flicker mitigation of variable speed wind......Due to the wind speed variation, wind shear and tower shadow effects, grid connected wind turbines are the sources of power fluctuations which may produce flicker during continuous operation. This paper presents a model of an MW-level variable-speed wind turbine with a doubly fed induction...

  15. Flicker Mitigation by Speed Control of Permanent Magnet Synchronous Generator Variable-Speed Wind Turbines

    DEFF Research Database (Denmark)

    Hu, Weihao; Zhang, Yunqian; Chen, Zhe

    2013-01-01

    operation. A new method of flicker mitigation by controlling the rotational speed is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the rotational speed of the PMSG. Simulation results show that damping the 3p active power...... oscillation by using the flicker mitigation speed controller is an effective means for flicker mitigation of variable speed wind turbines with full-scale back-to-back power converters and PMSG during continuous operation.......Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a full-scale back-to-back power converter and permanent magnet synchronous generator (PMSG...

  16. Social capital and adverse treatment outcomes of tuberculosis: a case-control study.

    Science.gov (United States)

    Deshmukh, P R; Mundra, A; Dawale, A

    2017-08-01

    'Social capital' refers to social norms, relationships, networks and values that affect the functioning and development of society. Social capital influences health positively, but its role in the treatment outcomes of tuberculosis (TB) is not known. To study the role of social capital in determining adverse TB treatment outcomes. Of 516 patients registered under the Revised National Tuberculosis Control Programme in 2014 in Wardha Tuberculosis Unit, Wardha, India, we included 88 patients with adverse treatment outcomes as cases and 187 controls from among those without adverse outcomes. Multiple logistic regression was used to compare standardised Z-scores. A greater proportion of controls than cases belonged to higher quartiles of social capital and its domains than cases, and the mean standardised Z-score was also consistently higher among controls than cases. Respectively 47% and 15% of cases and controls were in the poorest quartile of social capital, whereas respectively 10% and 33% of cases and controls were in the richest quartile. Each unit increase in Z-score of overall social capital reduced the odds of adverse treatment outcomes by 63.1%. Appropriate interventions for building social capital for TB patients and linking them with the programme would improve programme performance.

  17. Development and evaluation of an Individualized Outcome Measure (IOM) for randomized controlled trials in mental health.

    Science.gov (United States)

    Pesola, Francesca; Williams, Julie; Bird, Victoria; Freidl, Marion; Le Boutillier, Clair; Leamy, Mary; Macpherson, Rob; Slade, Mike

    2015-12-01

    Pre-defined, researcher-selected outcomes are routinely used as the clinical end-point in randomized controlled trials (RCTs); however, individualized approaches may be an effective way to assess outcome in mental health research. The present study describes the development and evaluation of the Individualized Outcome Measure (IOM), which is a patient-specific outcome measure to be used for RCTs of complex interventions. IOM was developed using a narrative review, expert consultation and piloting with mental health service users (n = 20). The final version of IOM comprises two components: Goal Attainment (GA) and Personalized Primary Outcome (PPO). For GA, patients identify one relevant goal at baseline and rate its attainment at follow-up. For PPO, patients choose an outcome domain related to their goal from a pre-defined list at baseline, and complete a standardized questionnaire assessing the chosen outcome domain at baseline and follow-up. A feasibility study indicated that IOM had adequate completion (89%) and acceptability (96%) rates in a clinical sample (n = 84). IOM was then evaluated in a RCT (ISRCTN02507940). GA and PPO components were associated with each other and with the trial primary outcome. The use of the PPO component of IOM as the primary outcome could be considered in future RCTs. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  18. AN OVERVIEW OF PHARMACEUTICAL PROCESS VALIDATION AND PROCESS CONTROL VARIABLES OF TABLETS MANUFACTURING PROCESSES IN INDUSTRY

    OpenAIRE

    Mahesh B. Wazade*, Sheelpriya R. Walde and Abhay M. Ittadwar

    2012-01-01

    Validation is an integral part of quality assurance; the product quality is derived from careful attention to a number of factors including selection of quality parts and materials, adequate product and manufacturing process design, control of the process variables, in-process and end-product testing. Recently validation has become one of the pharmaceutical industry’s most recognized and discussed subjects. It is a critical success factor in product approval and ongoing commercialization, fac...

  19. The Role of Organizational Control Systems in Employees’ Organizational Trust and Performance Outcomes

    NARCIS (Netherlands)

    Verburg, R.M.; Nienaber, Ann Marie; Searle, Rosalind H.; Weibel, Antoinette; Den Hartog, Deanne N.; Rupp, Deborah E.

    2018-01-01

    This study examined how organizational control is related to employees’ organizational trust. We specifically focus on how different forms of control (process, outcome, and normative) relate to employees’ trust in their employing organizations and examine whether such trust in turn relates

  20. The role of organizational control systems in employees’ organizational trust and performance outcomes

    NARCIS (Netherlands)

    Verburg, R.M.; Nienaber, A.; Searle, R.H.; Weibel, A.; Den Hartog, D.N.; Rupp, D.E.

    2018-01-01

    This study examined how organizational control is related to employees’ organizational trust. We specifically focus on how different forms of control (process, outcome, and normative) relate to employees’ trust in their employing organizations and examine whether such trust in turn relates

  1. Relationship of Personality and Locus of Control With Employment Outcomes among Participants with Spinal Cord Injury

    Science.gov (United States)

    Krause, James S.; Broderick, Lynne

    2006-01-01

    We investigated relationships among personality, locus of control, and current post-injury employment status for 1,391 participants with spinal cord injury. Participants with higher internality locus-of-control scores and activity scores (personality) reported more favorable employment outcomes. Higher scores on chance and powerful others (locus…

  2. Optimal sensor placement for control of a supersonic mixed-compression inlet with variable geometry

    Science.gov (United States)

    Moore, Kenneth Thomas

    A method of using fluid dynamics models for the generation of models that are useable for control design and analysis is investigated. The problem considered is the control of the normal shock location in the VDC inlet, which is a mixed-compression, supersonic, variable-geometry inlet of a jet engine. A quasi-one-dimensional set of fluid equations incorporating bleed and moving walls is developed. An object-oriented environment is developed for simulation of flow systems under closed-loop control. A public interface between the controller and fluid classes is defined. A linear model representing the dynamics of the VDC inlet is developed from the finite difference equations, and its eigenstructure is analyzed. The order of this model is reduced using the square root balanced model reduction method to produce a reduced-order linear model that is suitable for control design and analysis tasks. A modification to this method that improves the accuracy of the reduced-order linear model for the purpose of sensor placement is presented and analyzed. The reduced-order linear model is used to develop a sensor placement method that quantifies as a function of the sensor location the ability of a sensor to provide information on the variable of interest for control. This method is used to develop a sensor placement metric for the VDC inlet. The reduced-order linear model is also used to design a closed loop control system to control the shock position in the VDC inlet. The object-oriented simulation code is used to simulate the nonlinear fluid equations under closed-loop control.

  3. An Analysis of Variable-Speed Wind Turbine Power-Control Methods with Fluctuating Wind Speed

    Directory of Open Access Journals (Sweden)

    Seung-Il Moon

    2013-07-01

    Full Text Available Variable-speed wind turbines (VSWTs typically use a maximum power-point tracking (MPPT method to optimize wind-energy acquisition. MPPT can be implemented by regulating the rotor speed or by adjusting the active power. The former, termed speed-control mode (SCM, employs a speed controller to regulate the rotor, while the latter, termed power-control mode (PCM, uses an active power controller to optimize the power. They are fundamentally equivalent; however, since they use a different controller at the outer control loop of the machine-side converter (MSC controller, the time dependence of the control system differs depending on whether SCM or PCM is used. We have compared and analyzed the power quality and the power coefficient when these two different control modes were used in fluctuating wind speeds through computer simulations. The contrast between the two methods was larger when the wind-speed fluctuations were greater. Furthermore, we found that SCM was preferable to PCM in terms of the power coefficient, but PCM was superior in terms of power quality and system stability.

  4. Modeling and control of a variable-speed wind turbine equipped with permanent magnet synchronous generator

    Energy Technology Data Exchange (ETDEWEB)

    Aliprantis, D.C.; Papathanassiou, S.A.; Papadopoulos, M.P.; Kladas, A.G. [Purdue University, Electrical and Computer Engineering, West Lafayette, IN (United States)

    2000-08-01

    In this paper the operation of a variable-speed, stall regulated wind turbine equipped with a permanent magnet synchronous generator (PMSG) is examined. The emphasis is placed on the analysis of the electric part of the system, i.e. the electrical generator, the power electronics converters and the control. The operational characteristics of the machine are investigated through a series of computer simulations and the speed control system is designed to maximize the power output and achieve a smooth torque and power profile. (orig.)

  5. Control desacoplado de un actuador de rigidez variable para robots asistenciales

    Directory of Open Access Journals (Sweden)

    J. Medina

    2016-01-01

    Full Text Available Resumen: Los actuadores de rigidez variable son dispositivos que permiten cambiar la posición y rigidez articular de un robot en forma simultánea. En los últimos años se han diseñado y desarrollado muchos dispositivos de este tipo, con la esperanza de favorecer la seguridad en la interacción humano-robot y mejorar el rendimiento dinámico de los robots. En este artículo se presenta el desarrollo de un controlador para un actuador de rigidez variable de configuración serie. La estrategia de control se basa en la linealización por realimentación y el ajuste de dos controladores lineales. Esta estrategia permite el seguimiento de referencias de posición y rigidez articular de forma simultánea y desacoplada. Además, se realizan simulaciones en las que se incorpora este dispositivo dentro del robot asistencial ASIBOT, a fin de evaluar el desempeño del controlador, los cambios en la dinámica del robot y las posibles ventajas que tendrá la inclusión del mismo a nivel de seguridad en la interacción física humano-robot. Abstract: The variable stiffness actuators are devices that change the position and stiffness of a robot simultaneously. In recent years have been designed and developed many devices of this type, hoping to ensure safety in human-robot interaction and improve the dynamic performance of robots. In this article, we present the control of a variable stiffness actuator with serial configuration. The control strategy is based on feedback linearization and adjustment of two linear controllers. This allows the control, independently, of the stiffness and the equilibrium position of the joint. Finally, the behavior of this device within the assistive robot ASIBOT, is simulated in order to assess: the controller performance, changes in the dynamics of the robot and possible advantages of a level of safety during physical interaction human-robot. Palabras clave: control de robot

  6. Patient-important outcomes in randomized controlled trials in critically ill patients: a systematic review.

    Science.gov (United States)

    Gaudry, Stéphane; Messika, Jonathan; Ricard, Jean-Damien; Guillo, Sylvie; Pasquet, Blandine; Dubief, Emeline; Boukertouta, Tanissia; Dreyfuss, Didier; Tubach, Florence

    2017-12-01

    Intensivists' clinical decision making pursues two main goals for patients: to decrease mortality and to improve quality of life and functional status in survivors. Patient-important outcomes are gaining wide acceptance in most fields of clinical research. We sought to systematically review how well patient-important outcomes are reported in published randomized controlled trials (RCTs) in critically ill patients. Literature search was conducted to identify eligible trials indexed from January to December 2013. Articles were eligible if they reported an RCT involving critically ill adult patients. We excluded phase II, pilot and physiological crossover studies. We assessed study characteristics. All primary and secondary outcomes were collected, described and classified using six categories of outcomes including patient-important outcomes (involving mortality at any time on the one hand and quality of life, functional/cognitive/neurological outcomes assessed after ICU discharge on the other). Of the 716 articles retrieved in 2013, 112 RCTs met the inclusion criteria. Most common topics were mechanical ventilation (27%), sepsis (19%) and nutrition (17%). Among the 112 primary outcomes, 27 (24%) were patient-important outcomes (mainly mortality, 21/27) but only six (5%) were patient-important outcomes besides mortality assessed after ICU discharge (functional disability = 4; quality of life = 2). Among the 598 secondary outcomes, 133 (22%) were patient-important outcomes (mainly mortality, 92/133) but only 41 (7%) were patient-important outcomes besides mortality assessed after ICU discharge (quality of life = 20, functional disability = 14; neurological/cognitive performance = 5; handicap = 1; post-traumatic stress = 1). Seventy-three RCTs (65%) reported at least one patient-important outcome but only 11 (10%) reported at least one patient-important outcome besides mortality assessed after ICU discharge. Patient-important outcomes are rarely primary

  7. The outcome competency framework for practitioners in infection prevention and control: use of the outcome logic model for evaluation.

    Science.gov (United States)

    Burnett, E; Curran, E; Loveday, H P; Kiernan, M A; Tannahill, M

    2014-01-01

    Healthcare is delivered in a dynamic environment with frequent changes in populations, methods, equipment and settings. Infection prevention and control practitioners (IPCPs) must ensure that they are competent in addressing the challenges they face and are equipped to develop infection prevention and control (IPC) services in line with a changing world of healthcare provision. A multifaceted Framework was developed to assist IPCPs to enhance competence at an individual, team and organisational level to enable quality performance and improved quality of care. However, if these aspirations are to be met, it is vital that competency frameworks are fit for purpose or they risk being ignored. The aim of this unique study was to evaluate short and medium term outcomes as set out in the Outcome Logic Model to assist with the evaluation of the impact and success of the Framework. This study found that while the Framework is being used effectively in some areas, it is not being used as much or in the ways that were anticipated. The findings will enable future work on revision, communication and dissemination, and will provide intelligence to those initiating education and training in the utilisation of the competences.

  8. Comprehensive assessment of variables affecting metabolic control in patients with type 2 diabetes mellitus in Jordan.

    Science.gov (United States)

    Qteishat, Rola Reyad; Ghananim, Abdel Rahman Al

    2016-01-01

    The aim of the study was to identify variables affecting metabolic control among diabetic patients treated at diabetes and endocrine clinic in Jordan. A total of 200 patients were studied by using a cross sectional study design. Data were collected from patients' medical records, glycemic control tests and prestructured questionnaires about variables that were potentially important based on previous researches and clinical judgment: Adherence evaluation, Patients' knowledge about drug therapy and non-pharmacological therapy, Anxiety and depression, Beliefs about diabetes treatment (benefits and barriers of treatment), Knowledge about treatment goals, Knowledge about diabetes, Self efficacy, and Social support. The mean (±SD) age was 53.5 (±10.38) years and mean HbA1c was 8.4 (±1.95). In the multivariate analysis, education level, and self efficacy found to have significantly independent association with metabolic control (Pknowledge and high self efficacy was significant in patients with good metabolic control. Emphasizing the importance of continuous educational programs and improving the self efficacy as well, could warrant achieving good metabolic control. Copyright © 2015 Diabetes India. Published by Elsevier Ltd. All rights reserved.

  9. Surgical outcomes of laparoscopic hysterectomy with concomitant endometriosis without bowel or bladder dissection : A cohort analysis to define a case-mix variable

    NARCIS (Netherlands)

    Sandberg, Evelien M.; Driessen, Sara R C; Bak, Evelien A.T.; van Geloven, Nan; Berger, Judith P.; Smeets, Mathilde J.G.H.; Rhemrev, Johann P T; Jansen, F.W.

    2018-01-01

    Background: Pelvic endometriosis is often mentioned as one of the variables influencing surgical outcomes of laparoscopic hysterectomy (LH). However, its additional surgical risks have not been well established. The aim of this study was to analyze to what extent concomitant endometriosis

  10. Industrial implementation of spatial variability control by real-time SPC

    Science.gov (United States)

    Roule, O.; Pasqualini, F.; Borde, M.

    2016-10-01

    Advanced technology nodes require more and more information to get the wafer process well setup. The critical dimension of components decreases following Moore's law. At the same time, the intra-wafer dispersion linked to the spatial non-uniformity of tool's processes is not capable to decrease in the same proportions. APC systems (Advanced Process Control) are being developed in waferfab to automatically adjust and tune wafer processing, based on a lot of process context information. It can generate and monitor complex intrawafer process profile corrections between different process steps. It leads us to put under control the spatial variability, in real time by our SPC system (Statistical Process Control). This paper will outline the architecture of an integrated process control system for shape monitoring in 3D, implemented in waferfab.

  11. Artificial neural networks in variable process control: application in particleboard manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Esteban, L. G.; Garcia Fernandez, F.; Palacios, P. de; Conde, M.

    2009-07-01

    Artificial neural networks are an efficient tool for modelling production control processes using data from the actual production as well as simulated or design of experiments data. In this study two artificial neural networks were combined with the control process charts and it was checked whether the data obtained by the networks were valid for variable process control in particleboard manufacture. The networks made it possible to obtain the mean and standard deviation of the internal bond strength of the particleboard within acceptable margins using known data of thickness, density, moisture content, swelling and absorption. The networks obtained met the acceptance criteria for test values from non-standard test methods, as well as the criteria for using these values in statistical process control. (Author) 47 refs.

  12. DAC with LQR Control Design for Pitch Regulated Variable Speed Wind Turbine

    DEFF Research Database (Denmark)

    Imran, Raja Muhammad; Hussain, Dil Muhammad Akbar; Soltani, Mohsen

    2014-01-01

    Disturbance Accommodation Control (DAC) is used to model and simulate a system with known disturbance waveform. This paper presents a control scheme to mitigate the effect of disturbances by using collective pitch control for the aboverated wind speed (Region III) for a variable speed wind turbine....... We have used Linear Quadratic Regulator (LQR) to obtain full state feedback gain, disturbance feedback gain is calculated independently and then estimator gain is achieved by poleplacement technique in the DAC augmented plant model. The reduced order model (two-mass model) of wind turbine is used...... and 5MW National Renewable Energy Laboratory (NREL) wind turbine is used in this research. We have shown comparison of results relating to pitch angle, drive train torsion and generator speed obtained by a PID controller and DAC. Simulations are performed in MATLAB/Simulink. The results are compared...

  13. Executive Summary of the NHLBI Workshop Report: Leveraging Current Scientific Advancements to Understand Sarcoidosis Variability and Improve Outcomes.

    Science.gov (United States)

    Maier, Lisa A; Crouser, Elliott D; Martin, William J; Eu, Jerry

    2017-12-01

    Sarcoidosis is a systemic granulomatous disease that primarily affects the lung; it is associated with significant disparities, more commonly impacting those in the prime of their lives (age 20-50 yr, with a second peak after age 60 yr), black individuals, and women. However, the burden of disease, the ability to diagnose and prognose organ involvement and course, as well as specific treatment options, management options, and disease pathogenesis remain poorly understood. As a result, the National Heart, Lung, and Blood Institute undertook a sarcoidosis workshop, "Leveraging Current Scientific Advancements to Understand Sarcoidosis Variability and Improve Outcomes," to help address these issues by defining the scientific and clinical priorities to improve sarcoidosis care. The overarching recommendations from this workshop are outlined in the following summary and detailed in the accompanying articles. The recommendations included establishing collaborations and networks to conduct research based on consensus definitions of disease phenotypes and standards of care, and to provide clinical outreach to areas with a burden of disease to improve care. These collaborative networks would also serve as the hub to conduct clinical trials of devastating phenotypes (e.g., cardiac, neurologic, and fibrotic disease) not only for treatment but to enhance our understanding of the burden of disease. In addition, the networks would be used to leverage state-of-the-art "omics" and systems biology research, as well as other studies to advance understanding of disease pathogenesis, and development of biomarkers and therapeutic targets, with a goal to translate this information to improve care of individuals with sarcoidosis.

  14. Bubble CPAP versus CPAP with variable flow in newborns with respiratory distress: a randomized controlled trial.

    Science.gov (United States)

    Yagui, Ana Cristina Zanon; Vale, Luciana Assis Pires Andrade; Haddad, Luciana Branco; Prado, Cristiane; Rossi, Felipe Souza; Deutsch, Alice D Agostini; Rebello, Celso Moura

    2011-01-01

    To evaluate the efficacy and safety of nasal continuous positive airway pressure (NCPAP) using devices with variable flow or bubble continuous positive airway pressure (CPAP) regarding CPAP failure, presence of air leaks, total CPAP and oxygen time, and length of intensive care unit and hospital stay in neonates with moderate respiratory distress (RD) and birth weight (BW) ≥ 1,500 g. Forty newborns requiring NCPAP were randomized into two study groups: variable flow group (VF) and continuous flow group (CF). The study was conducted between October 2008 and April 2010. Demographic data, CPAP failure, presence of air leaks, and total CPAP and oxygen time were recorded. Categorical outcomes were tested using the chi-square test or the Fisher's exact test. Continuous variables were analyzed using the Mann-Whitney test. The level of significance was set at p CPAP failure (21.1 and 20.0% for VF and CF, respectively; p = 1.000), air leak syndrome (10.5 and 5.0%, respectively; p = 0.605), total CPAP time (median: 22.0 h, interquartile range [IQR]: 8.00-31.00 h and median: 22.0 h, IQR: 6.00-32.00 h, respectively; p = 0.822), and total oxygen time (median: 24.00 h, IQR: 7.00-85.00 h and median: 21.00 h, IQR: 9.50-66.75 h, respectively; p = 0.779). In newborns with BW ≥ 1,500 g and moderate RD, the use of continuous flow NCPAP showed the same benefits as the use of variable flow NCPAP.

  15. Combining biological and psychosocial baseline variables did not improve prediction of outcome of a very-low-energy diet in a clinic referral population.

    Science.gov (United States)

    Sumithran, P; Purcell, K; Kuyruk, S; Proietto, J; Prendergast, L A

    2018-02-01

    Consistent, strong predictors of obesity treatment outcomes have not been identified. It has been suggested that broadening the range of predictor variables examined may be valuable. We explored methods to predict outcomes of a very-low-energy diet (VLED)-based programme in a clinically comparable setting, using a wide array of pre-intervention biological and psychosocial participant data. A total of 61 women and 39 men (mean ± standard deviation [SD] body mass index: 39.8 ± 7.3 kg/m 2 ) underwent an 8-week VLED and 12-month follow-up. At baseline, participants underwent a blood test and assessment of psychological, social and behavioural factors previously associated with treatment outcomes. Logistic regression, linear discriminant analysis, decision trees and random forests were used to model outcomes from baseline variables. Of the 100 participants, 88 completed the VLED and 42 attended the Week 60 visit. Overall prediction rates for weight loss of ≥10% at weeks 8 and 60, and attrition at Week 60, using combined data were between 77.8 and 87.6% for logistic regression, and lower for other methods. When logistic regression analyses included only baseline demographic and anthropometric variables, prediction rates were 76.2-86.1%. In this population, considering a wide range of biological and psychosocial data did not improve outcome prediction compared to simply-obtained baseline characteristics. © 2017 World Obesity Federation.

  16. Locus of control, self-efficacy, and the mediating effect of outcome control: predicting course-level and global outcomes in an academic context.

    Science.gov (United States)

    Au, Evelyn W M

    2015-01-01

    The current study utilizes Skinner's framework to examine the unique contributions of internal locus of control, self-efficacy, and perceived outcome control over course performance on students' academic experiences. Undergraduate students (N = 225) took part in a longitudinal study and completed two surveys (Time 1: just before their mid-term exams; Time 2: just before their final exam in the same semester). Both locus of control and self-efficacy at Time 1 predicted course-level perceived control over course performance at Time 2. Student-level perceived control over course performance at Time 2 mediated the relationship between self-efficacy at Time 1 and course-level perseverance, course-specific stress, and course enjoyment at Time 2. For global perceived stress and life satisfaction measured at Time 2, both locus of control and self-efficacy at Time 1 had only a direct effect on global perceived stress at Time 2, but only self-efficacy at Time 1 predicted life satisfaction at Time 2. Both locus of control and self-efficacy uniquely contribute to students' academic experiences. Student-level perceived control plays an important mediating role between locus of control and self-efficacy at Time 1, and course-level perseverance, course-specific stress, and course enjoyment at Time 2.

  17. Variations of high frequency parameter of heart rate variability following osteopathic manipulative treatment in healthy subjects compared to control group and sham therapy: randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Nuria eRuffini

    2015-08-01

    Full Text Available Context: Heart Rate Variability (HRV indicates how heart rate changes in response to inner and external stimuli. HRV is linked to health status and it is an indirect marker of the autonomic nervous system (ANS function. Objective: To investigate the influence of osteopathic manipulative treatment (OMT on ANS activity through changes of High Frequency, a heart rate variability index indicating the parasympathetic activity, in healthy subjects, compared with sham therapy and control group.Methods: Sixty-six healthy subjects, both male and female, were included in the present 3-armed randomized placebo controlled within subject cross-over single blinded study. Participants were asymptomatic adults, both smokers and non-smokers and not on medications. At enrollment subjects were randomized in 3 groups: A, B, C. Standardized structural evaluation followed by a patient need-based osteopathic treatment was performed in the first session of group A and in the second session of group B. Standardized evaluation followed by a protocoled sham treatment was provided in the second session of group A and in the first session of group B. No intervention was performed in the two sessions of group C, acting as a time-control. The trial was registered on clinicaltrials.gov identifier: NCT01908920.Main Outcomes Measures: HRV was calculated from electrocardiography before, during and after the intervention, for a total amount time of 25 minutes.Results: OMT engendered a statistically significant increase of parasympathetic activity, as shown by High Frequency rate (p<0.001, and decrease of sympathetic activity, as revealed by Low Frequency rate (p<0.01; results also showed a reduction of Low Frequency/High Frequency ratio (p<0.001 and Detrended fluctuation scaling exponent (p<0.05. Conclusions: Findings suggested that OMT can influence ANS activity increasing parasympathetic function and decreasing sympathetic activity, compared to sham therapy and control group.

  18. Effects of Yoga on Stress, Stress Adaption, and Heart Rate Variability Among Mental Health Professionals--A Randomized Controlled Trial.

    Science.gov (United States)

    Lin, Shu-Ling; Huang, Ching-Ya; Shiu, Shau-Ping; Yeh, Shu-Hui

    2015-08-01

    Mental health professionals experiencing work-related stress may experience burn out, leading to a negative impact on their organization and patients. The aim of this study was to examine the effects of yoga classes on work-related stress, stress adaptation, and autonomic nerve activity among mental health professionals. A randomized controlled trial was used, which compared the outcomes between the experimental (e.g., yoga program) and the control groups (e.g., no yoga exercise) for 12 weeks. Work-related stress and stress adaptation were assessed before and after the program. Heart rate variability (HRV) was measured at baseline, midpoint through the weekly yoga classes (6 weeks), and postintervention (after 12 weeks of yoga classes). The results showed that the mental health professionals in the yoga group experienced a significant reduction in work-related stress (t = -6.225, p control group revealed no significant changes. Comparing the mean differences in pre- and posttest scores between yoga and control groups, we found the yoga group significantly decreased work-related stress (t = -3.216, p = .002), but there was no significant change in stress adaptation (p = .084). While controlling for the pretest scores of work-related stress, participants in yoga, but not the control group, revealed a significant increase in autonomic nerve activity at midpoint (6 weeks) test (t = -2.799, p = .007), and at posttest (12 weeks; t = -2.099, p = .040). Because mental health professionals experienced a reduction in work-related stress and an increase in autonomic nerve activity in a weekly yoga program for 12 weeks, clinicians, administrators, and educators should offer yoga classes as a strategy to help health professionals reduce their work-related stress and balance autonomic nerve activities. © 2015 The Authors. Worldviews on Evidence-Based Nursing published by Wiley Periodicals, Inc. on behalf of Society for Worldviews on Evidence-Based Nursing.

  19. A general method for handling missing binary outcome data in randomized controlled trials

    OpenAIRE

    Jackson, Dan; White, Ian R; Mason, Dan; Sutton, Stephen

    2014-01-01

    Aims The analysis of randomized controlled trials with incomplete binary outcome data is challenging. We develop a general method for exploring the impact of missing data in such trials, with a focus on abstinence outcomes. Design We propose a sensitivity analysis where standard analyses, which could include ‘missing = smoking’ and ‘last observation carried forward’, are embedded in a wider class of models. Setting We apply our general method to data from two smoking cessation trials. Partici...

  20. Implementation of EPICS based vacuum control system for variable energy cyclotron centre, Kolkata

    Science.gov (United States)

    Roy, Anindya; Bhole, R. B.; Nandy, Partha P.; Yadav, R. C.; Pal, Sarbajit; Roy, Amitava

    2015-03-01

    The vacuum system of the Room Temperature (K = 130) Cyclotron of Variable Energy Cyclotron Centre is comprised of vacuum systems of main machine and Beam Transport System. The vacuum control system is upgraded to a PLC based Automated system from the initial relay based Manual system. The supervisory control of the vacuum system is implemented in Experimental Physics and Industrial Control System (EPICS). An EPICS embedded ARM based vacuum gauge controller is developed to mitigate the requirement of vendor specific gauge controller for gauges and also for seamless integration of the gauge controllers with the control system. A set of MS-Windows ActiveX components with embedded EPICS Channel Access interface are developed to build operator interfaces with less complex programming and to incorporate typical Windows feature, e.g., user authentication, file handling, better fonts, colors, mouse actions etc. into the operator interfaces. The control parameters, monitoring parameters, and system interlocks of the system are archived in MySQL based EPICS MySQL Archiver developed indigenously. In this paper, we describe the architecture, the implementation details, and the performance of the system.

  1. Implementation of EPICS based vacuum control system for variable energy cyclotron centre, Kolkata

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Anindya, E-mail: r-ani@vecc.gov.in; Bhole, R. B.; Nandy, Partha P.; Yadav, R. C.; Pal, Sarbajit; Roy, Amitava [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064 (India)

    2015-03-15

    The vacuum system of the Room Temperature (K = 130) Cyclotron of Variable Energy Cyclotron Centre is comprised of vacuum systems of main machine and Beam Transport System. The vacuum control system is upgraded to a PLC based Automated system from the initial relay based Manual system. The supervisory control of the vacuum system is implemented in Experimental Physics and Industrial Control System (EPICS). An EPICS embedded ARM based vacuum gauge controller is developed to mitigate the requirement of vendor specific gauge controller for gauges and also for seamless integration of the gauge controllers with the control system. A set of MS-Windows ActiveX components with embedded EPICS Channel Access interface are developed to build operator interfaces with less complex programming and to incorporate typical Windows feature, e.g., user authentication, file handling, better fonts, colors, mouse actions etc. into the operator interfaces. The control parameters, monitoring parameters, and system interlocks of the system are archived in MySQL based EPICS MySQL Archiver developed indigenously. In this paper, we describe the architecture, the implementation details, and the performance of the system.

  2. Implementation of EPICS based vacuum control system for variable energy cyclotron centre, Kolkata

    International Nuclear Information System (INIS)

    Roy, Anindya; Bhole, R. B.; Nandy, Partha P.; Yadav, R. C.; Pal, Sarbajit; Roy, Amitava

    2015-01-01

    The vacuum system of the Room Temperature (K = 130) Cyclotron of Variable Energy Cyclotron Centre is comprised of vacuum systems of main machine and Beam Transport System. The vacuum control system is upgraded to a PLC based Automated system from the initial relay based Manual system. The supervisory control of the vacuum system is implemented in Experimental Physics and Industrial Control System (EPICS). An EPICS embedded ARM based vacuum gauge controller is developed to mitigate the requirement of vendor specific gauge controller for gauges and also for seamless integration of the gauge controllers with the control system. A set of MS-Windows ActiveX components with embedded EPICS Channel Access interface are developed to build operator interfaces with less complex programming and to incorporate typical Windows feature, e.g., user authentication, file handling, better fonts, colors, mouse actions etc. into the operator interfaces. The control parameters, monitoring parameters, and system interlocks of the system are archived in MySQL based EPICS MySQL Archiver developed indigenously. In this paper, we describe the architecture, the implementation details, and the performance of the system

  3. Surgical outcomes of laparoscopic hysterectomy with concomitant endometriosis without bowel or bladder dissection: a cohort analysis to define a case-mix variable.

    Science.gov (United States)

    Sandberg, Evelien M; Driessen, Sara R C; Bak, Evelien A T; van Geloven, Nan; Berger, Judith P; Smeets, Mathilde J G H; Rhemrev, Johann P T; Jansen, Frank Willem

    2018-01-01

    Pelvic endometriosis is often mentioned as one of the variables influencing surgical outcomes of laparoscopic hysterectomy (LH). However, its additional surgical risks have not been well established. The aim of this study was to analyze to what extent concomitant endometriosis influences surgical outcomes of LH and to determine if it should be considered as case-mix variable. A total of 2655 LH's were analyzed, of which 397 (15.0%) with concomitant endometriosis. For blood loss and operative time, no measurable association was found for stages I ( n  = 106) and II ( n  = 103) endometriosis compared to LH without endometriosis. LH with stages III ( n  = 93) and IV ( n  = 95) endometriosis were associated with more intra-operative blood loss ( p  = case-mix variables in future quality measurement tools.

  4. A balance of activity in brain control and reward systems predicts self-regulatory outcomes

    OpenAIRE

    Lopez, Richard B.; Chen, Pin-Hao A.; Huckins, Jeremy F.; Hofmann, Wilhelm; Kelley, William M.; Heatherton, Todd F.

    2017-01-01

    Abstract Previous neuroimaging work has shown that increased reward-related activity following exposure to food cues is predictive of self-control failure. The balance model suggests that self-regulation failures result from an imbalance in reward and executive control mechanisms. However, an open question is whether the relative balance of activity in brain systems associated with executive control (vs reward) supports self-regulatory outcomes when people encounter tempting cues in daily lif...

  5. Evaluation of feedforward and feedback contributions to hand stiffness and variability in multijoint arm control.

    Science.gov (United States)

    He, Xin; Du, Yu-Fan; Lan, Ning

    2013-07-01

    The purpose of this study is to validate a neuromechanical model of the virtual arm (VA) by comparing emerging behaviors of the model to those of experimental observations. Hand stiffness of the VA model was obtained by either theoretical computation or simulated perturbations. Variability in hand position of the VA was generated by adding signal dependent noise (SDN) to the motoneuron pools of muscles. Reflex circuits of Ia, Ib and Renshaw cells were included to regulate the motoneuron pool outputs. Evaluation of hand stiffness and variability was conducted in simulations with and without afferent feedback under different patterns of muscle activations during postural maintenance. The simulated hand stiffness and variability ellipses captured the experimentally observed features in shape, magnitude and orientation. Steady state afferent feedback contributed significantly to the increase in hand stiffness by 35.75±16.99% in area, 18.37±7.80% and 16.15±7.15% in major and minor axes; and to the reduction of hand variability by 49.41±21.19% in area, 36.89±12.78% and 18.87±23.32% in major and minor axes. The VA model reproduced the neuromechanical behaviors that were consistent with experimental data, and it could be a useful tool for study of neural control of posture and movement, as well as for application to rehabilitation.

  6. Effect of an office worksite-based yoga program on heart rate variability: A randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Chang Dennis

    2011-07-01

    Full Text Available Abstract Background Chronic work-related stress is a significant and independent risk factor for cardiovascular and metabolic diseases and associated mortality, particularly when compounded by a sedentary work environment. Heart rate variability (HRV provides an estimate of parasympathetic and sympathetic autonomic control, and can serve as a marker of physiological stress. Hatha yoga is a physically demanding practice that can help to reduce stress; however, time constraints incurred by work and family life may limit participation. The purpose of the present study is to determine if a 10-week, worksite-based yoga program delivered during lunch hour can improve resting HRV and related physical and psychological parameters in sedentary office workers. Methods and design This is a parallel-arm RCT that will compare the outcomes of participants assigned to the experimental treatment group (yoga to those assigned to a no-treatment control group. Participants randomized to the experimental condition will engage in a 10-week yoga program delivered at their place of work. The yoga sessions will be group-based, prescribed three times per week during lunch hour, and will be led by an experienced yoga instructor. The program will involve teaching beginner students safely and progressively over 10 weeks a yoga sequence that incorporates asanas (poses and postures, vinyasa (exercises, pranayama (breathing control and meditation. The primary outcome of this study is the high frequency (HF spectral power component of HRV (measured in absolute units; i.e. ms2, a measure of parasympathetic autonomic control. Secondary outcomes include additional frequency and time domains of HRV, and measures of physical functioning and psychological health status. Measures will be collected prior to and following the intervention period, and at 6 months follow-up to determine the effect of intervention withdrawal. Discussion This study will determine the effect of worksite

  7. Vibration control of an energy regenerative seat suspension with variable external resistance

    Science.gov (United States)

    Ning, Donghong; Sun, Shuaishuai; Du, Haiping; Li, Weihua; Zhang, Nong

    2018-06-01

    In this paper, an energy regenerative seat suspension with a variable external resistance is proposed and built, and a semi-active controller for its vibration control is also designed and validated. The energy regenerative seat suspension is built with a three-phase generator and a gear reducer, which are installed in the scissors structure centre of the seat suspension, and the vibration energy is directly harvested from the rotary movement of suspension's scissors structure. The electromagnetic torque of the semi-active seat suspension actuator is controlled by an external variable resistor. An integrated model including the seat suspension's kinematics and the generator is built and proven to match the test result very well. A simplified experimental phenomenon model is also built based on the test results for the controller design. A state feedback H∞ controller is proposed for the regenerative seat suspension's semi-active vibration control. The proposed regenerative seat suspension and its controller are validated with both simulations and experiments. A well-tuned passive seat suspension is applied to evaluate the regenerative seat's performance. Based on ISO 2631-1, the frequency-weighted root mean square (FW-RMS) acceleration of the proposed seat suspension has a 22.84% reduction when compared with the passive one, which indicates the improvement of ride comfort. At the same time, the generated RMS power is 1.21 W. The proposed regenerative seat suspension can greatly improve the driver's ride comfort and has the potential to be developed to a self-powered semi-active system.

  8. A new control-oriented transient model of variable geometry turbocharger

    International Nuclear Information System (INIS)

    Bahiuddin, Irfan; Mazlan, Saiful Amri; Imaduddin, Fitrian; Ubaidillah

    2017-01-01

    The flow input of a variable geometry turbocharger turbine is highly unsteady due to rapid and periodic pressure dynamics in engine combustion chambers. Several VGT control methods have been developed to recover more energy from the highly pulsating exhaust gas flow. To develop a control system for the highly pulsating flow condition, an accurate and valid unsteady model is required. This study focuses on the derivation of governing the unsteady control-oriented model (COM) for a turbine of an actively controlled turbocharger (ACT). The COM has the capability to predict the turbocharger behaviour regarding the instantaneous turbine actual and isentropic powers in different effective throat areas. The COM is a modified version of a conventional mean value model (MVM) with an additional feature to calculate the turbine angular velocity and torque for determining the actual power. The simulation results were further compared with experimental data in two general scenarios. The first scenario was simulations on fixed geometry positions. The second simulation scenario considered the nozzle movement after receiving a signal from the controller in different cases. The comparison between simulation and experimental results showed similarities in the recovered power behaviours the turbine inlet area increases or vice versa. The model also has proved its reliability to replicate general behaviour as in the example of ACT cases presented in this paper. However, the model is incapable to replicate the detailed and complicated phenomena, such as choking effect and hysteresis effect. - Highlights: • A control-oriented model of a variable geometry turbocharger turbine is proposed. • Isentropic and actual power behaviour estimations on turbocharger turbine. • A simulation tool for developing active control systems of turbocharger turbines.

  9. Development, field testing and implementation of automated hydraulically controlled, variable volume loading systems for reciprocating compressors

    Energy Technology Data Exchange (ETDEWEB)

    Hickman, Dwayne A. [ACI Services, Inc., Cambridge, OH (United States); Slupsky, John [Kvaerner Process Systems, Calgary, Alberta (Canada); Chrisman, Bruce M.; Hurley, Tom J. [Cooper Energy Services, Oklahoma City, OK (United States). Ajax Division

    2003-07-01

    Automated, variable volume unloaders provide the ability to smoothly load/unload reciprocating compressors to maintain ideal operations in ever-changing environments. Potential advantages provided by this load control system include: maximizing unit capacity, optimizing power economy, maintaining low exhaust emissions, and maintaining process suction and discharge pressures. Obstacles foreseen include: reliability, stability, serviceability and automation integration. Results desired include: increased productivity for the compressor and its operators, increased up time, and more stable process control. This presentation covers: system design features with descriptions of how different types of the devices were developed, initial test data, and how they can be effectively operated; three actual-case studies detailing the reasons why automated, hydraulically controlled, variable volume, head-end unloaders were chosen over other types of unloading devices; sophisticated software used in determining the device sizing and predicted performance; mechanical and field considerations; installation, serviceability and operating considerations; device control issues, including PC and PLC considerations; monitoring of actual performance and comparison of such with predicted performance; analysis of mechanical reliability and stability; and preliminary costs versus return on investment analysis. (author)

  10. Flicker Mitigation by Speed Control of Permanent Magnet Synchronous Generator Variable-Speed Wind Turbines

    Directory of Open Access Journals (Sweden)

    Yanting Hu

    2013-07-01

    Full Text Available Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a full-scale back-to-back power converter and permanent magnet synchronous generator (PMSG developed in the simulation tool of PSCAD/EMTDC. Flicker emission of this system is investigated. The 3p (three times per revolution power oscillation due to wind shear and tower shadow effects is the significant part in the flicker emission of variable speed wind turbines with PMSG during continuous operation. A new method of flicker mitigation by controlling the rotational speed is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the rotational speed of the PMSG. Simulation results show that damping the 3p active power oscillation by using the flicker mitigation speed controller is an effective means for flicker mitigation of variable speed wind turbines with full-scale back-to-back power converters and PMSG during continuous operation.

  11. Variability in proactive and reactive cognitive control processes across the adult lifespan

    Directory of Open Access Journals (Sweden)

    Frini eKarayanidis

    2011-11-01

    Full Text Available Task-switching paradigms produce a highly consistent age-related increase in mixing cost (longer RT on repeat trials in mixed-task than single task blocks but a less consistent age effect on switch cost (longer RT on switch than repeat trials in mixed-task blocks. We use two approaches to examine the adult lifespan trajectory of control processes contributing to mixing cost and switch cost: latent variables derived from an evidence accumulation model of choice, and event-related potentials (ERP that temporally differentiate proactive (cue-driven and reactive (target-driven control processes. Under highly practiced and prepared task conditions, ageing was associated with increasing RT mixing cost but reducing RT switch cost. Both effects were largely due to the same cause: an age effect for mixed-repeat trials. In terms of latent variables, increasing age was associated with slower non-decision processes, slower rate of evidence accumulation about the target, and higher response criterion. Age effects on mixing costs were evident only on response criterion, the amount of evidence required to trigger a decision, whereas age effects on switch cost were present for all three latent variables. ERPs showed age-related increases in preparation for mixed-repeat trials, anticipatory attention, and post-target interference. Cue-locked ERPs that are linked to proactive control were associated with early emergence of age differences in response criterion. These results are consistent with age effects on strategic processes controlling decision caution. Consistent with an age-related decline in cognitive flexibility, younger adults flexibly adjusted response criterion from trial-to-trial on mixed-task blocks, whereas older adults maintained a high criterion for all trials.

  12. Smoothing Control of Wind Farm Output by Using Kinetic Energy of Variable Speed Wind Power Generators

    Science.gov (United States)

    Sato, Daiki; Saitoh, Hiroumi

    This paper proposes a new control method for reducing fluctuation of power system frequency through smoothing active power output of wind farm. The proposal is based on the modulation of rotaional kinetic energy of variable speed wind power generators through power converters between permanent magnet synchronous generators (PMSG) and transmission lines. In this paper, the proposed control is called Fluctuation Absorption by Flywheel Characteristics control (FAFC). The FAFC can be easily implemented by adding wind farm output signal to Maximum Power Point Tracking control signal through a feedback control loop. In order to verify the effectiveness of the FAFC control, a simulation study was carried out. In the study, it was assumed that the wind farm consisting of PMSG type wind power generator and induction machine type wind power generaotors is connected with a power sysem. The results of the study show that the FAFC control is a useful method for reducing the impacts of wind farm output fluctuation on system frequency without additional devices such as secondary battery.

  13. Torque control of synchronous and induction generators for variable speed operation of wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Ola; Ulen, E. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Electric Power Engineering

    1996-12-01

    The aim of this paper is to investigate variable speed electrical systems. Synchronous generators with diode rectifiers and line-commutated thyristor converters are compared with induction generators with force commutated transistor converters and scalar control. The system characteristics are examined regarding possible speed of response (bandwidth) of the torque control, including the sensitivity to disturbances for the drive train and also the possibility to get damping of the drive train resonance. Analyses, simulations and laboratory tests with a 40 kW machine set-up have been performed. The investigation shows that the system with synchronous generator is well suited for wind power applications. A rapid standard DC-current regulator is included in the torque control and can be used for damping of the resonance. The torque control has a bandwidth up to about 3 Hz and the DC-voltage controller up to about 1 Hz. The system with induction generator with scalar control (no transformations) is more difficult to control. A linear approach is only possible up to about 1.5 Hz. In this region it turns out that the behaviour can be visualized as an added inertia on the generator side that can be rather big. 4 refs, 9 figs

  14. Magnitude and Variability of Controllable Charge Capacity Provided by Grid Connected Plug-in Electric Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Scoffield, Don R [Idaho National Lab. (INL), Idaho Falls, ID (United States); Smart, John [Idaho National Lab. (INL), Idaho Falls, ID (United States); Salisbury, Shawn [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    As market penetration of plug-in electric vehicles (PEV) increases over time, the number of PEVs charging on the electric grid will also increase. As the number of PEVs increases, their ability to collectively impact the grid increases. The idea of a large body of PEVs connected to the grid presents an intriguing possibility. If utilities can control PEV charging, it is possible that PEVs could act as a distributed resource to provide grid services. The technology required to control charging is available for modern PEVs. However, a system for wide-spread implementation of controllable charging, including robust communication between vehicles and utilities, is not currently present. Therefore, the value of controllable charging must be assessed and weighed against the cost of building and operating such as system. In order to grasp the value of PEV charge control to the utility, the following must be understood: 1. The amount of controllable energy and power capacity available to the utility 2. The variability of the controllable capacity from day to day and as the number of PEVs in the market increases.

  15. Transient and dynamic control of a variable speed wind turbine with synchronous generator

    Energy Technology Data Exchange (ETDEWEB)

    Jauch, Clemens [Riso National Laboratory, Wind Energy Department, PO Box 49, DK 4000 Roskilde, (Denmark)

    2007-02-14

    In this article, a controller for dynamic and transient control of a variable speed wind turbine with a full-scale converter-connected high-speed synchronous generator is presented. First, the phenomenon of drive train oscillations in wind turbines with full-scale converter-connected generators is discussed. Based on this discussion, a controller is presented that dampens these oscillations without impacting on the power that the wind turbine injects into the grid. Since wind turbines are increasingly demanded to take over power system stabilizing and control tasks, the presented wind turbine design is further enhanced to support the grid in transient grid events. A controller is designed that allows the wind turbine to ride through transient grid faults. Since such faults often cause power system oscillations, another controller is added that enables the turbine to participate in the damping of such oscillations. It is concluded that the controllers presented keep the wind turbine stable under any operating conditions, and that they are capable of adding substantial damping to the power system. (Author).

  16. Global control of reaction wheel pendulum through energy regulation and extended linearization of the state variables

    Directory of Open Access Journals (Sweden)

    Oscar D. Montoya-Giraldo

    2014-01-01

    Full Text Available This paper presents the design and simulation of a global controller for the Reaction Wheel Pendulum system using energy regulation and extended linearization methods for the state feedback. The proposed energy regulation is based on the gradual reduction of the energy of the system to reach the unstable equilibrium point. The signal input for this task is obtained from the Lyapunov stability theory. The extended state feedback controller design is used to get a smooth nonlinear function that extends the region of operation to a bigger range, in contrast with the static linear state feedback obtained through the method of approximate linearization around an operating point. The general designed controller operates with a switching between the two control signals depending upon the region of operation; perturbations are applied in the control signal and the (simulated measured variables to verify the robustness and efficiency of the controller. Finally, simulations and tests using the model of the reaction wheel pendulum system, allow to observe the versatility and functionality of the proposed controller in the entire operation region of the pendulum.

  17. Nonlinear model-based control of the Czochralski process III: Proper choice of manipulated variables and controller parameter scheduling

    Science.gov (United States)

    Neubert, M.; Winkler, J.

    2012-12-01

    This contribution continues an article series [1,2] about the nonlinear model-based control of the Czochralski crystal growth process. The key idea of the presented approach is to use a sophisticated combination of nonlinear model-based and conventional (linear) PI controllers for tracking of both, crystal radius and growth rate. Using heater power and pulling speed as manipulated variables several controller structures are possible. The present part tries to systematize the properties of the materials to be grown in order to get unambiguous decision criteria for a most profitable choice of the controller structure. For this purpose a material specific constant M called interface mobility and a more process specific constant S called system response number are introduced. While the first one summarizes important material properties like thermal conductivity and latent heat the latter one characterizes the process by evaluating the average axial thermal gradients at the phase boundary and the actual growth rate at which the crystal is grown. Furthermore these characteristic numbers are useful for establishing a scheduling strategy for the PI controller parameters in order to improve the controller performance. Finally, both numbers give a better understanding of the general thermal system dynamics of the Czochralski technique.

  18. EMG Versus Torque Control of Human-Machine Systems: Equalizing Control Signal Variability Does not Equalize Error or Uncertainty.

    Science.gov (United States)

    Johnson, Reva E; Kording, Konrad P; Hargrove, Levi J; Sensinger, Jonathon W

    2017-06-01

    In this paper we asked the question: if we artificially raise the variability of torque control signals to match that of EMG, do subjects make similar errors and have similar uncertainty about their movements? We answered this question using two experiments in which subjects used three different control signals: torque, torque+noise, and EMG. First, we measured error on a simple target-hitting task in which subjects received visual feedback only at the end of their movements. We found that even when the signal-to-noise ratio was equal across EMG and torque+noise control signals, EMG resulted in larger errors. Second, we quantified uncertainty by measuring the just-noticeable difference of a visual perturbation. We found that for equal errors, EMG resulted in higher movement uncertainty than both torque and torque+noise. The differences suggest that performance and confidence are influenced by more than just the noisiness of the control signal, and suggest that other factors, such as the user's ability to incorporate feedback and develop accurate internal models, also have significant impacts on the performance and confidence of a person's actions. We theorize that users have difficulty distinguishing between random and systematic errors for EMG control, and future work should examine in more detail the types of errors made with EMG control.

  19. Microcontroller Based Proportional Derivative Plus Conditional Integral Controller for Electro-Mechanical Dual Acting Pulley Continuously Variable Transmission Ratio Control

    International Nuclear Information System (INIS)

    Budianto, A; Tawi, K B; Hussein, M; Supriyo, B; Kob, M S Che; Zulkifli, Mohd Ezlamy; Khairuldean A K; Daraoh, Aishah; Ariyono, S

    2012-01-01

    Electro-Mechanical Dual Acting Pulley (EMDAP) Continuously Variable Transmission (CVT) is a transmission utilized by electro-mechanical actuated system. It has a potential to reduce energy consumption because it only needs power during changing CVT ratio and no power is needed to maintain CVT ratio due to self lock mechanism design. This paper proposed simple proportional derivative plus conditional integral (PDCI) controller to control EMDAP CVT ratio which can be simply implemented on a microcontroller. This proposed controller used Astrom-Hagglund method and Ziegler-Nichols formula to tune PDCI gain. The Proportional Derivative controller is directly activated from the start but Integral controller is only activated when the error value reaches error value setting point. Simulation using Matlab/Simulink software was conducted to evaluate PDCI system performance. The simulation results showed PDCI controller has ability to perform maximum overshoot 0.1%, 0.001 steady state error and 0.5s settling time. For clamping condition, settling time is about 11.46s during changing ratio from 2.0 to 0.7, while for release condition, settling time is about 8.33s during changing ratio from 0.7 to 2.0.

  20. Global Control of the Furuta Pendulum Using Artificial Neural Networks and Feedback of State Variables

    Directory of Open Access Journals (Sweden)

    Luisa F. Escobar-Dávila

    2013-06-01

    Full Text Available This paper presents the mathematical modeling of the Furuta Pendu-lum by power functions, taking into account the non linear own dynamics of the physical systems and considering the existing couplings between the electric and mechanic devices. A control process based on feedback of state variables (FSV for the equilibrium point is developed and two topics for the non linear zone are addressed. First of all, functions are implemented to represent the energetic states of the plant in a global way and the operation regions are established (“Swing up” zone, and later Artificial Neural Networks (ANN are employed to simulate the behavior of the energy functions. Finally, it is presented the combination between the control techniques, considering the own constrains of the actuators and sensors used, besides of this, a study is done in a simulated environment of the physical phenomena that may disturb system behavior, and the capacity, sensitivity and robustness of the controller is verified.

  1. Flip, flop and fly: modulated motor control and highly variable movement patterns of autotomized gecko tails.

    Science.gov (United States)

    Higham, Timothy E; Russell, Anthony P

    2010-02-23

    Many animals lose and regenerate appendages, and tail autotomy in lizards is an extremely well-studied example of this. Whereas the energetic, ecological and functional ramifications of tail loss for many lizards have been extensively documented, little is known about the behaviour and neuromuscular control of the autotomized tail. We used electromyography and high-speed video to quantify the motor control and movement patterns of autotomized tails of leopard geckos (Eublepharis macularius). In addition to rhythmic swinging, we show that they exhibit extremely complex movement patterns for up to 30 min following autotomy, including acrobatic flips up to 3 cm in height. Unlike the output of most central pattern generators (CPGs), muscular control of the tail is variable and can be arrhythmic. We suggest that the gecko tail is well suited for studies involving CPGs, given that this spinal preparation is naturally occurring, requires no surgery and exhibits complex modulation.

  2. Feedback linearization based control of a variable air volume air conditioning system for cooling applications.

    Science.gov (United States)

    Thosar, Archana; Patra, Amit; Bhattacharyya, Souvik

    2008-07-01

    Design of a nonlinear control system for a Variable Air Volume Air Conditioning (VAVAC) plant through feedback linearization is presented in this article. VAVAC systems attempt to reduce building energy consumption while maintaining the primary role of air conditioning. The temperature of the space is maintained at a constant level by establishing a balance between the cooling load generated in the space and the air supply delivered to meet the load. The dynamic model of a VAVAC plant is derived and formulated as a MIMO bilinear system. Feedback linearization is applied for decoupling and linearization of the nonlinear model. Simulation results for a laboratory scale plant are presented to demonstrate the potential of keeping comfort and maintaining energy optimal performance by this methodology. Results obtained with a conventional PI controller and a feedback linearizing controller are compared and the superiority of the proposed approach is clearly established.

  3. Variable speed wind turbine control by discrete-time sliding mode approach.

    Science.gov (United States)

    Torchani, Borhen; Sellami, Anis; Garcia, Germain

    2016-05-01

    The aim of this paper is to propose a new design variable speed wind turbine control by discrete-time sliding mode approach. This methodology is designed for linear saturated system. The saturation constraint is reported on inputs vector. To this end, the back stepping design procedure is followed to construct a suitable sliding manifold that guarantees the attainment of a stabilization control objective. It is well known that the mechanisms are investigated in term of the most proposed assumptions to deal with the damping, shaft stiffness and inertia effect of the gear. The objectives are to synthesize robust controllers that maximize the energy extracted from wind, while reducing mechanical loads and rotor speed tracking combined with an electromagnetic torque. Simulation results of the proposed scheme are presented. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  4. A chaos-based image encryption algorithm with variable control parameters

    International Nuclear Information System (INIS)

    Wang Yong; Wong, K.-W.; Liao Xiaofeng; Xiang Tao; Chen Guanrong

    2009-01-01

    In recent years, a number of image encryption algorithms based on the permutation-diffusion structure have been proposed. However, the control parameters used in the permutation stage are usually fixed in the whole encryption process, which favors attacks. In this paper, a chaos-based image encryption algorithm with variable control parameters is proposed. The control parameters used in the permutation stage and the keystream employed in the diffusion stage are generated from two chaotic maps related to the plain-image. As a result, the algorithm can effectively resist all known attacks against permutation-diffusion architectures. Theoretical analyses and computer simulations both confirm that the new algorithm possesses high security and fast encryption speed for practical image encryption.

  5. Two-phase strategy of neural control for planar reaching movements: I. XY coordination variability and its relation to end-point variability.

    Science.gov (United States)

    Rand, Miya K; Shimansky, Yury P

    2013-03-01

    A quantitative model of optimal transport-aperture coordination (TAC) during reach-to-grasp movements has been developed in our previous studies. The utilization of that model for data analysis allowed, for the first time, to examine the phase dependence of the precision demand specified by the CNS for neurocomputational information processing during an ongoing movement. It was shown that the CNS utilizes a two-phase strategy for movement control. That strategy consists of reducing the precision demand for neural computations during the initial phase, which decreases the cost of information processing at the expense of lower extent of control optimality. To successfully grasp the target object, the CNS increases precision demand during the final phase, resulting in higher extent of control optimality. In the present study, we generalized the model of optimal TAC to a model of optimal coordination between X and Y components of point-to-point planar movements (XYC). We investigated whether the CNS uses the two-phase control strategy for controlling those movements, and how the strategy parameters depend on the prescribed movement speed, movement amplitude and the size of the target area. The results indeed revealed a substantial similarity between the CNS's regulation of TAC and XYC. First, the variability of XYC within individual trials was minimal, meaning that execution noise during the movement was insignificant. Second, the inter-trial variability of XYC was considerable during the majority of the movement time, meaning that the precision demand for information processing was lowered, which is characteristic for the initial phase. That variability significantly decreased, indicating higher extent of control optimality, during the shorter final movement phase. The final phase was the longest (shortest) under the most (least) challenging combination of speed and accuracy requirements, fully consistent with the concept of the two-phase control strategy. This paper

  6. Thrust distribution for attitude control in a variable thrust propulsion system with four ACS nozzles

    Science.gov (United States)

    Lim, Yeerang; Lee, Wonsuk; Bang, Hyochoong; Lee, Hosung

    2017-04-01

    A thrust distribution approach is proposed in this paper for a variable thrust solid propulsion system with an attitude control system (ACS) that uses a reduced number of nozzles for a three-axis attitude maneuver. Although a conventional variable thrust solid propulsion system needs six ACS nozzles, this paper proposes a thrust system with four ACS nozzles to reduce the complexity and mass of the system. The performance of the new system was analyzed with numerical simulations, and the results show that the performance of the system with four ACS nozzles was similar to the original system while the mass of the whole system was simultaneously reduced. Moreover, a feasibility analysis was performed to determine whether a thrust system with three ACS nozzles is possible.

  7. Psychosocial outcome and psychiatric comorbidity in older adolescents with Tourette syndrome: controlled study

    DEFF Research Database (Denmark)

    Gorman, Daniel A; Thompson, Nancy; Plessen, Kerstin J

    2010-01-01

    BACKGROUND: Children with Tourette syndrome generally experience improvement of tics by age 18 years, but psychosocial and comorbidity outcomes at this age are unclear. AIMS: To compare psychosocial outcomes and lifetime comorbidity rates in older adolescents with Tourette syndrome and controls. We...... hypothesised a priori that individuals with Tourette syndrome would have lower Children's Global Assessment Scale (CGAS) scores. METHOD: A total of 65 individuals with Tourette syndrome, identified in childhood, and 65 matched community controls without tic or obsessive-compulsive disorder (OCD) symptoms were......, learning disorder and conduct disorder (Ptic severity. CONCLUSIONS: Clinically ascertained children with Tourette syndrome typically have impaired psychosocial functioning...

  8. Moderation of effects of AAC based on setting and types of aided AAC on outcome variables: an aggregate study of single-case research with individuals with ASD.

    Science.gov (United States)

    Ganz, Jennifer B; Rispoli, Mandy J; Mason, Rose Ann; Hong, Ee Rea

    2014-06-01

    The purpose of this meta-analysis was to evaluate the potential moderating effects of intervention setting and type of aided augmentative and alternative communication (AAC) on outcome variables for students with autism spectrum disorders. Improvement rate difference, an effect size measure, was used to calculate aggregate effects across 35 single-case research studies. Results indicated that the largest effects for aided AAC were observed in general education settings. With respect to communication outcomes, both speech generating devices (SGDs) and the Picture Exchange Communication System (PECS) were associated with larger effects than other picture-based systems. With respect to challenging behaviour outcomes, SGDs produced larger effects than PECS. This aggregate study highlights the importance of considering intervention setting, choice of AAC system and target outcomes when designing and planning an aided AAC intervention.

  9. Early functional outcome of two different orthotic concepts in ankle sprains: a randomized controlled trial.

    Science.gov (United States)

    Best, Raymond; Böhle, Caroline; Schiffer, Thorsten; Petersen, Wolf; Ellermann, Andree; Brueggemann, Gert Peter; Liebau, Christian

    2015-07-01

    Purpose of the study was the evaluation of the early functional outcome of patients with an acute ankle sprain treated either with a semirigid, variable, phase-adapted modular ankle orthosis or an invariable orthotic reference device. Forty-seven patients with acute ankle sprain grade II or more were included. In addition, 77 healthy controls as a reference were investigated. The injured subjects were treated with one of the two devices by random for 6 weeks. Ankle scores (FAOS, AOFAS) were taken at baseline after injury, 1 and 3 months after injury. Functional performance tests (balance platform, zig zag run, shuttle run, vertical drop jump) were performed at 1 and 3 months after injury. No significant score differences could be found between the two intervention groups except for achieving a preinjury activity level after 3 months only in the modular orthosis group. Postural functional performances (balance test) also showed no significant differences whereas the results of the agility tests revealed small but significant better results in the modular orthosis group in comparison to the invariable orthosis group. Cohen's effect sizes were high. Differences between the two intervention groups were marginal and very small but significant and--regarding Cohen's effect sizes--effective. Especially relating to functional performance, this might be a careful indication that a more effective strategy for promoting a protected, rapid recovery to physical activity after ankle sprains might be achieved by applying a phase-adapted ankle orthosis. Especially in athletic patients, phase-adapted orthosis should be further investigated and considered to ensure fully protected ligament healing as well as to regain early functional recovery.

  10. Controlling the taxonomic variable: Taxonomic concept resolution for a southeastern United States herbarium portal

    Directory of Open Access Journals (Sweden)

    Nico Franz

    2016-09-01

    the Euler/X logic reasoning toolkit to provide comprehensive genus- to variety-level concept alignments for at least 10 major flora treatments with highest relevance to SERNEC. The visualizations and estimated > 1 billion inferred concept-to-concept relations will effectively drive specimen data integration in the transformed portal. (3 We will expand Symbiota's taxonomy and occurrence schemas and related user interfaces to support the new concept data, including novel batch and map-based specimen determination modules, with easy output options in Darwin Core Archive format. (4 Through combinations of the new technology, enlisted taxonomic expertise, and SERNEC's large image resources, we will upgrade minimally 80% of all SERNEC specimen identifications from names to the narrowest suitable TCLs, or add "uncertainty" flags to specimens needing further study. (5 We will utilize the novel tools and data to demonstrate how controlling for the taxonomic variable in 12 use cases variously drives the outcomes of evolutionary, ecological, and conservation-based research hypotheses. Broader impacts. Our project is focused on just one herbarium network, but the potential impact is as wide as Darwin Core or even comparative biology. We believe that trust in networked biodiversity data depends on open and dynamic system designs, allowing expert access and resolution of multiple conflicting views that reflect the complex realities of ongoing taxonomic research. Taking well over 1 million SERNEC records from name- to TCL-resolution will show that "big" specimen data can pass the credibility threshold needed to validate the substantive data mobilization investment. We will mentor one postdoctoral researcher (UNC, two Ph.D. students (ASU, UIUC, and at least 15 undergraduate students (ASU. Each of our workshops will capacitate 10-15 SERNEC experts, who in turn can recruit colleagues and students at their home collections. We will incorporate the project theme and use cases into

  11. 变速变桨风力机组控制策略研究%Research on the Control Strategy for Variable Speed and Variable Pitch Wind Turbine

    Institute of Scientific and Technical Information of China (English)

    陈铁军; 汪兆财

    2012-01-01

    In order to increase the utilization efficiency of wind energy of wind turbine power generation system, and improve the quality of output electric energy, with the chaotic system theory as the core, the control structure of chaotic automation used for variable speed and variable pitch wind turbine is established. In addition, combining with fuzzy control theory, the algorithm of controller is given. The simulation of the control structure and control algorithm shows that comparing with conventional control method, the variable speed and variable pitch wind turbine with chaotic automation control structure and under control algorithm reaches predicted target, the practical control effect is excellent.%为提高风力机发电系统的风能利用效率、改善输出电能质量,针对变速变桨风力发电机组的控制问题,以混杂系统理论为核心,建立了应用于变速变桨风力机组的混杂自动机控制结构.同时,结合模糊控制理论,给出控制器的算法.通过对该控制结构和控制算法的仿真表明,与常规的控制方法相比,采用混杂自动机控制结构和控制算法控制变速变桨风力机组,既提高了风能的利用效率,又很好地改善了风力机输出电能质量,实际控制效果良好.

  12. Measurement and control of bias in patient reported outcomes using multidimensional item response theory.

    Science.gov (United States)

    Dowling, N Maritza; Bolt, Daniel M; Deng, Sien; Li, Chenxi

    2016-05-26

    Patient-reported outcome (PRO) measures play a key role in the advancement of patient-centered care research. The accuracy of inferences, relevance of predictions, and the true nature of the associations made with PRO data depend on the validity of these measures. Errors inherent to self-report measures can seriously bias the estimation of constructs assessed by the scale. A well-documented disadvantage of self-report measures is their sensitivity to response style (RS) effects such as the respondent's tendency to select the extremes of a rating scale. Although the biasing effect of extreme responding on constructs measured by self-reported tools has been widely acknowledged and studied across disciplines, little attention has been given to the development and systematic application of methodologies to assess and control for this effect in PRO measures. We review the methodological approaches that have been proposed to study extreme RS effects (ERS). We applied a multidimensional item response theory model to simultaneously estimate and correct for the impact of ERS on trait estimation in a PRO instrument. Model estimates were used to study the biasing effects of ERS on sum scores for individuals with the same amount of the targeted trait but different levels of ERS. We evaluated the effect of joint estimation of multiple scales and ERS on trait estimates and demonstrated the biasing effects of ERS on these trait estimates when used as explanatory variables. A four-dimensional model accounting for ERS bias provided a better fit to the response data. Increasing levels of ERS showed bias in total scores as a function of trait estimates. The effect of ERS was greater when the pattern of extreme responding was the same across multiple scales modeled jointly. The estimated item category intercepts provided evidence of content independent category selection. Uncorrected trait estimates used as explanatory variables in prediction models showed downward bias. A

  13. Intensive perioperative glucose control does not improve outcomes of patients submitted to open-heart surgery: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Raquel Pei Chen Chan

    2009-01-01

    Full Text Available BACKGROUND: The objective of this study was to investigate the relationship between different target levels of glucose and the clinical outcomes of patients undergoing cardiac surgery with cardiopulmonary bypass. METHODS: We designed a prospective study in a university hospital where 109 consecutive patients were enrolled during a six-month period. All patients were scheduled for open-heart surgery requiring cardiopulmonary bypass. Patients were randomly allocated into two groups. One group consisted of 55 patients and had a target glucose level of 80-130 mg/dl, while the other contained 54 patients and had a target glucose level of 160-200 mg/dl. These parameters were controlled during surgery and for 36 hours after surgery in the intensive care unit. Primary outcomes were clinical outcomes, including time of mechanical ventilation, length of stay in the intensive care unit, infection, hypoglycemia, renal or neurological dysfunction, blood transfusion and length of stay in the hospital. The secondary outcome was a combined end-point (mortality at 30 days, infection or length of stay in the intensive care unit of more than 3 days. A p-value of 0.05. CONCLUSIONS: In 109 patients undergoing cardiac surgery with cardiopulmonary bypass, both protocols of glycemic control in an intraoperative setting and in the intensive care unit were found to be safe, easily achieved and not to differentially affect clinical outcomes.

  14. Integration of Variable Speed Pumped Hydro Storage in Automatic Generation Control Systems

    Science.gov (United States)

    Fulgêncio, N.; Moreira, C.; Silva, B.

    2017-04-01

    Pumped storage power (PSP) plants are expected to be an important player in modern electrical power systems when dealing with increasing shares of new renewable energies (NRE) such as solar or wind power. The massive penetration of NRE and consequent replacement of conventional synchronous units will significantly affect the controllability of the system. In order to evaluate the capability of variable speed PSP plants participation in the frequency restoration reserve (FRR) provision, taking into account the expected performance in terms of improved ramp response capability, a comparison with conventional hydro units is presented. In order to address this issue, a three area test network was considered, as well as the corresponding automatic generation control (AGC) systems, being responsible for re-dispatching the generation units to re-establish power interchange between areas as well as the system nominal frequency. The main issue under analysis in this paper is related to the benefits of the fast response of variable speed PSP with respect to its capability of providing fast power balancing in a control area.

  15. Performance of a 3 kW wind turbine generator with variable pitch control system

    International Nuclear Information System (INIS)

    Nagai, Baku M.; Ameku, Kazumasa; Roy, Jitendro Nath

    2009-01-01

    A prototype 3 kW horizontal upwind type wind turbine generator of 4 m in diameter has been designed and examined under real wind conditions. The machine was designed based on the concept that even small wind turbines should have a variable pitch control system just as large wind turbines, especially in Japan where typhoons occur at least once a year. A characteristic of the machine is the use of a worm and gear system with a stepping motor installed in the center of the hub, and the rotational main shaft. The machine is constructed with no mechanical breaking system so as to avoid damage from strong winds. In a storm, the wind turbine is slowed down by adjusting the pitch angle and the maximum electrical load. Usually the machine is controlled at several stages depending on the rotational speed of the blades. Two control methods have been applied: the variable pitch angle, and regulation of the generator field current. The characteristics of the generator under each rotational speed and field current are first investigated in the laboratory. This paper describes the performances of the wind turbine in terms of the functions of wind turbine rotational speed, generated outputs, and its stability for wind speed changes. The expected performances of the machine have been confirmed under real wind conditions and compared with numerical simulation results. The wind turbine showed a power coefficient of 0.257 under the average wind speed of 7.3 m/s.

  16. Variable valve trains for internal combustion engines to control the valve height and the opening time; Variable Ventiltriebe fuer Verbrennungsmotoren zur Veraenderung von Ventilhub und Oeffnungsdauer

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Gunther [ThyssenKrupp Presta TecCenter AG, Eschen (Liechtenstein). R and D Projects

    2009-11-15

    The PDVC (Presta Delta Valve Control) continuously variable valve lift system is a mechanical system of valve control for achieving optimum performance and resulting in improved fuel consumption and reduced emissions across the entire operating range of the combustion engine. The continuous variability allows for engine load control by adjusting the valve height and therefore can also be used to replace the traditional throttle. The advantages are lower fuel consumption, reduction in emissions, quicker engine response, higher torque during the low speed range as well as more stable idling. The PSVC (Presta Shiftable Valve Control) is a 3 step shiftable valve lift system that offers the possibility to achieve a major part of these performance and associated consumption benefits with a simpler and therefore more cost-effective system. (orig.)

  17. The mediation proportion: a structural equation approach for estimating the proportion of exposure effect on outcome explained by an intermediate variable

    DEFF Research Database (Denmark)

    Ditlevsen, Susanne; Christensen, Ulla; Lynch, John

    2005-01-01

    It is often of interest to assess how much of the effect of an exposure on a response is mediated through an intermediate variable. However, systematic approaches are lacking, other than assessment of a surrogate marker for the endpoint of a clinical trial. We review a measure of "proportion...... of several intermediate variables. Binary or categorical variables can be included directly through threshold models. We call this measure the mediation proportion, that is, the part of an exposure effect on outcome explained by a third, intermediate variable. Two examples illustrate the approach. The first...... example is a randomized clinical trial of the effects of interferon-alpha on visual acuity in patients with age-related macular degeneration. In this example, the exposure, mediator and response are all binary. The second example is a common problem in social epidemiology-to find the proportion...

  18. Differential effects of absent visual feedback control on gait variability during different locomotion speeds.

    Science.gov (United States)

    Wuehr, M; Schniepp, R; Pradhan, C; Ilmberger, J; Strupp, M; Brandt, T; Jahn, K

    2013-01-01

    Healthy persons exhibit relatively small temporal and spatial gait variability when walking unimpeded. In contrast, patients with a sensory deficit (e.g., polyneuropathy) show an increased gait variability that depends on speed and is associated with an increased fall risk. The purpose of this study was to investigate the role of vision in gait stabilization by determining the effects of withdrawing visual information (eyes closed) on gait variability at different locomotion speeds. Ten healthy subjects (32.2 ± 7.9 years, 5 women) walked on a treadmill for 5-min periods at their preferred walking speed and at 20, 40, 70, and 80 % of maximal walking speed during the conditions of walking with eyes open (EO) and with eyes closed (EC). The coefficient of variation (CV) and fractal dimension (α) of the fluctuations in stride time, stride length, and base width were computed and analyzed. Withdrawing visual information increased the base width CV for all walking velocities (p < 0.001). The effects of absent visual information on CV and α of stride time and stride length were most pronounced during slow locomotion (p < 0.001) and declined during fast walking speeds. The results indicate that visual feedback control is used to stabilize the medio-lateral (i.e., base width) gait parameters at all speed sections. In contrast, sensory feedback control in the fore-aft direction (i.e., stride time and stride length) depends on speed. Sensory feedback contributes most to fore-aft gait stabilization during slow locomotion, whereas passive biomechanical mechanisms and an automated central pattern generation appear to control fast locomotion.

  19. Fuzzy-TLBO optimal reactive power control variables planning for energy loss minimization

    International Nuclear Information System (INIS)

    Moghadam, Ahmad; Seifi, Ali Reza

    2014-01-01

    Highlights: • A new approach to the problem of optimal reactive power control variables planning is proposed. • The energy loss minimization problem has been formulated by modeling the load of system as a Load Duration Curve. • To solving the energy loss problem, the classic methods and the evolutionary methods are used. • A new proposed fuzzy teaching–learning based algorithm is applied to energy loss problem. • Simulations are done to show the effectiveness and superiority of the proposed algorithm compared with other methods. - Abstract: This paper offers a new approach to the problem of optimal reactive power control variables planning (ORPVCP). The basic idea is division of Load Duration Curve (LDC) into several time intervals with constant active power demand in each interval and then solving the energy loss minimization (ELM) problem to obtain an optimal initial set of control variables of the system so that is valid for all time intervals and can be used as an initial operating condition of the system. In this paper, the ELM problem has been solved by the linear programming (LP) and fuzzy linear programming (Fuzzy-LP) and evolutionary algorithms i.e. MHBMO and TLBO and the results are compared with the proposed Fuzzy-TLBO method. In the proposed method both objective function and constraints are evaluated by membership functions. The inequality constraints are embedded into the fitness function by the membership function of the fuzzy decision and the problem is modeled by fuzzy set theory. The proposed Fuzzy-TLBO method is performed on the IEEE 30 bus test system by considering two different LDC; and it is shown that using this method has further minimized objective function than original TLBO and other optimization techniques and confirms its potential to solve the ORPCVP problem with considering ELM as the objective function

  20. Randomised controlled trial of a healthy lifestyle intervention among smokers with psychotic disorders: Outcomes to 36 months.

    Science.gov (United States)

    Baker, Amanda L; Richmond, Robyn; Kay-Lambkin, Frances J; Filia, Sacha L; Castle, David; Williams, Jill M; Lewin, Terry J; Clark, Vanessa; Callister, Robin; Palazzi, Kerrin

    2018-03-01

    People living with psychotic disorders (schizophrenia spectrum and bipolar disorders) have high rates of cardiovascular disease risk behaviours, including smoking, physical inactivity and poor diet. We report cardiovascular disease risk, smoking cessation and other risk behaviour outcomes over 36 months following recruitment into a two-arm randomised controlled trial among smokers with psychotic disorders. Participants ( N = 235) drawn from three sites were randomised to receive nicotine replacement therapy plus (1) a Healthy Lifestyles intervention delivered over approximately 9 months or (2) a largely telephone-delivered intervention (designed to control for nicotine replacement therapy provision, session frequency and other monitoring). The primary outcome variables were 10-year cardiovascular disease risk and smoking status, while the secondary outcomes included weekly physical activity, unhealthy eating, waist circumference, psychiatric symptomatology, depression and global functioning. Significant reductions in cardiovascular disease risk and smoking were detected across the 36-month follow-up period in both intervention conditions, with no significant differences between conditions. One-quarter (25.5%) of participants reported reducing cigarettes per day by 50% or more at multiple post-treatment assessments; however, few (8.9%) managed to sustain this across the majority of time points. Changes in other health behaviours or lifestyle factors were modest; however, significant improvements in depression and global functioning were detected over time in both conditions. Participants experiencing worse 'social discomfort' at baseline (e.g. anxiety, mania, poor self-esteem and social disability) had on average significantly worse global functioning, lower scores on the 12-Item Short Form Health Survey physical scale and significantly greater waist circumference. Although the telephone-delivered intervention was designed as a comparison condition, it

  1. Outcome prediction in mild traumatic brain injury: age and clinical variables are stronger predictors than CT abnormalities.

    NARCIS (Netherlands)

    Jacobs, B.; Beems, T.; Stulemeijer, M.; Vugt, A.B. van; Vliet, A.M. van der; Borm, G.F.; Vos, P.E.

    2010-01-01

    Mild traumatic brain injury (mTBI) is a common heterogeneous neurological disorder with a wide range of possible clinical outcomes. Accurate prediction of outcome is desirable for optimal treatment. This study aimed both to identify the demographic, clinical, and computed tomographic (CT)

  2. Examining the relationships between span of control and manager job and unit performance outcomes.

    Science.gov (United States)

    Wong, Carol A; Elliott-Miller, Pat; Laschinger, Heather; Cuddihy, Michael; Meyer, Raquel M; Keatings, Margaret; Burnett, Camille; Szudy, Natalie

    2015-03-01

    Our aim was to examine the combination of frontline manager (FLM) personal characteristics and span of control (SOC) on their job and unit performance outcomes. Healthcare downsizing and reform have contributed to larger spans for FLMs in Canadian hospitals and increased concerns about manager workload. Despite a heightened awareness of SOC issues among decision makers, there is limited empirical evidence related to the effects of SOC on outcomes. A non-experimental predictive survey design was used to examine FLM SOC in 14 Canadian academic hospitals. Managers (n = 121) completed an online survey of work characteristics and The Ottawa Hospital (TOH) SOC tool. Unit turnover data were collected from organisational databases. The combination of SOC and core self-evaluation significantly predicted role overload, work control and job satisfaction, but only SOC predicted unit adverse outcomes and neither significantly predicted unit turnover. The findings contribute to an understanding of connections between the combination of SOC and core self-evaluation and manager job and unit performance outcomes. Organisational strategies to create manageable FLM SOC are essential to ensure exemplary job and unit outcomes. Core self-evaluation is a personality characteristic that may enhance manager performance in the face of high spans of control. © 2013 John Wiley & Sons Ltd.

  3. Information content of neural networks with self-control and variable activity

    International Nuclear Information System (INIS)

    Bolle, D.; Amari, S.I.; Dominguez Carreta, D.R.C.; Massolo, G.

    2001-01-01

    A self-control mechanism for the dynamics of neural networks with variable activity is discussed using a recursive scheme for the time evolution of the local field. It is based upon the introduction of a self-adapting time-dependent threshold as a function of both the neural and pattern activity in the network. This mechanism leads to an improvement of the information content of the network as well as an increase of the storage capacity and the basins of attraction. Different architectures are considered and the results are compared with numerical simulations

  4. How plantar exteroceptive efficiency modulates postural and oculomotor control: inter-individual variability

    Directory of Open Access Journals (Sweden)

    Arnaud eFoisy

    2016-05-01

    Full Text Available In a previous experiment, we showed that among young and healthy subjects, thin plantar inserts improve postural control and modify vergence amplitudes. In this experiment, however, significant inter-individual variability was observed. We hypothesize that its origin could be attributed to a different reliance upon feet cutaneous afferents. In order to test this hypothesis, we re-analyzed the data relative to 31 young (age 25,7±3,8 and healthy subjects who participated in the first experiment after having classified them into two groups depending on their Plantar Quotient (PQ = Surface area of CoP foam / Surface area of CoP firm ground x100. Foam decreases the information arising from the feet, normally resulting in a PQ>100. Hence, the PQ provides information on the weight of plantar cutaneous afferents used in postural control. Twelve people were Plantar-Independent Subjects, as indicated by a PQ<100. These individuals did not behave like the Normal Plantar Quotient Subjects: they were almost insensitive to the plantar stimulations in terms of postural control and totally insensitive in terms of oculomotor control. We conclude that the inter-individual variability observed in our first experiment is explained by the subjects’ degree of plantar reliance. We propose that plantar independence is a dysfunctional situation revealing an inefficiency in plantar cutaneous afferents. The latter could be due to a latent somatosensory dysfunction generating a noise which prevents the CNS from correctly processing and using feet somatosensory afferents both for balance and vergence control: Plantar Irritating Stimulus. Considering the non-noxious nature and prevalence of this phenomenon, these results can be of great interest to researchers and clinicians who attempt to trigger postural or oculomotor responses through mechanical stimulation of the foot sole.

  5. Effects of Balance Control Training on Functional Outcomes in Subacute Hemiparetic Stroke Patients.

    Science.gov (United States)

    Huh, Jin Seok; Lee, Yang-Soo; Kim, Chul-Hyun; Min, Yu-Sun; Kang, Min-Gu; Jung, Tae-Du

    2015-12-01

    To investigate the efficacy of balance control training using a newly developed balance control trainer (BalPro) on the balance and gait of patients with subacute hemiparetic stroke. Forty-three subacute stroke patients were assigned to either a balance control training (BCT) group or a control group. The BCT group (n=23) was trained with BalPro for 30 minutes a day, 5 days a week for 2 weeks, and received one daily session of conventional physical therapy. The control group (n=20) received two sessions of conventional physical therapy every day for 2 weeks. The primary outcome was assessment with the Berg Balance Scale (BBS). Secondary outcomes were Functional Ambulation Category (FAC), the 6-minute walking test (6mWT), Timed Up and Go (TUG), the Korean version of Modified Barthel Index (K-MBI), and the manual muscle test (MMT) of the knee extensor. All outcome measures were evaluated before and after 2 weeks of training in both groups. There were statistically significant improvements in all parameters except MMT and FAC after 2 weeks of treatment in both groups. After training, the BCT group showed greater improvements in the BBS and the 6mWT than did the control group. Balance control training using BalPro could be a useful treatment for improving balance and gait in subacute hemiparetic stroke patients.

  6. Randomized Control Trial of COMPASS for Improving Transition Outcomes of Students with Autism Spectrum Disorder.

    Science.gov (United States)

    Ruble, Lisa A; McGrew, John H; Toland, Michael; Dalrymple, Nancy; Adams, Medina; Snell-Rood, Claire

    2018-06-01

    The postsecondary outcomes of individuals with autism spectrum disorder (ASD) are significantly worse than peers with other disabilities. One problem is the lack of empirically-supported transition planning interventions to guide services and help produce better outcomes. We applied an implementation science approach to adapt and modify an evidence-based consultation intervention originally tested with young children called the Collaborative Model for Promoting Competence and Success (COMPASS; Ruble et al., The collaborative model for promoting competence and success for students with ASD. Springer, New York, 2012a) and evaluate it for efficacy in a randomized controlled trial for transition-age youth. Results replicated findings with younger students with ASD that IEP outcomes were higher for COMPASS compared to the placebo control group (d = 2.1). Consultant fidelity was high and teacher adherence improved over time, replicating the importance of ongoing teacher coaching.

  7. Antenatal psychosomatic programming to reduce postpartum depression risk and improve childbirth outcomes: a randomized controlled trial in Spain and France.

    Science.gov (United States)

    Ortiz Collado, Maria Assumpta; Saez, Marc; Favrod, Jérôme; Hatem, Marie

    2014-01-15

    Postpartum depression (PPD) and poor childbirth outcomes are associated with poverty; these variables should be addressed by an adapted approach. The aim of this research was to evaluate the impact of an antenatal programme based on a novel psychosomatic approach to pregnancy and delivery, regarding the risk of PPD and childbirth outcomes in disadvantaged women. A multi-centre, randomized, controlled trial comparing a novel to standard antenatal programme. Primary outcome was depressive symptoms (using EPDS) and secondary outcome was preterm childbirth (fewer 37 weeks). The sample comprised 184 couples in which the women were identified to be at PPD risk by validated interview. The study was conducted in three public hospitals with comparable standards of perinatal care. Women were randomly distributed in to an experimental group (EG) or a control group (CG), and evaluated twice: during pregnancy (T1) and four weeks post-partum (T2). At T2, the variables were compared using the chi square test. Data analysis was based on intention to treat. The novel programme used the Tourné psychosomatic approach focusing on body awareness sensations, construction of an individualized childbirth model, and attachment. The 10 group antenatal sessions each lasted two hours, with one telephone conversation between sessions. In the control group, the participants choose the standard model of antenatal education, i.e., 8 to 10 two-hour sessions focused on childbirth by obstetrical prophylaxis. A difference of 11.2% was noted in postpartum percentages of PPD risk (EPDS ≥ 12): 34.3% (24) in EG and 45.5% (27) in CG (p = 0.26). The number of depressive symptoms among EG women decreased at T2 (intragroup p = 0.01). Premature childbirth was four times less in EG women: three (4.4%) compared to 13 (22.4%) among CG women (p = 0.003). Birth weight was higher in EG women (p = 0.01). The decrease of depressive symptoms in women was not conclusive. However, because birth weight was higher and

  8. Multidisciplinary Treatment of the Metabolic Syndrome Lowers Blood Pressure Variability Independent of Blood Pressure Control.

    Science.gov (United States)

    Marcus, Yonit; Segev, Elad; Shefer, Gabi; Sack, Jessica; Tal, Brurya; Yaron, Marianna; Carmeli, Eli; Shefer, Lili; Margaliot, Miri; Limor, Rona; Gilad, Suzan; Sofer, Yael; Stern, Naftali

    2016-01-01

    Blood pressure (BP) variability (BPV) contributes to target organ damage independent of BP. The authors examined the effect of a 1-year multidisciplinary intervention on BPV in patients with the metabolic syndrome (MetS) as defined by criteria from the Third Report of the Adult Treatment Panel. Forty-four nondiabetic patients underwent clinical and biochemical profiling, 24-hour ambulatory BP monitoring (ABPM), body composition, carotid intima-media thickness, and carotid-femoral pulse wave velocity (PWV). The intervention targeted all MetS components. BPV was assessed by the standard deviation of daytime systolic BP derived from ABPM. Patients with low and high BPV (lower or higher than the median daytime standard deviation of 11.6 mm Hg) did not differ in regards to systolic and diastolic BP, age, fasting glucose, glycated hemoglobin, and body mass index, but the high-variability group had higher values of low-density lipoprotein and leg fat. The 1-year intervention resulted in weight reduction but not BP-lowering. BPV declined in the high-variability group in association with lowering of PWV, C-reactive protein, glycated hemoglobin, alanine aminotransferase, asymmetric dimethylarginine, and increased high-density lipoprotein cholesterol. A multidisciplinary intervention independent of BP-lowering normalized BPV, lowered PWV, and enhanced metabolic control. © 2015 Wiley Periodicals, Inc.

  9. Impulsivity, Working Memory, and Impaired Control over Alcohol: A Latent Variable Analysis

    Science.gov (United States)

    Wardell, Jeffrey D.; Quilty, Lena C.; Hendershot, Christian S.

    2017-01-01

    Impaired control over alcohol is an important risk factor for heavy drinking among young adults and may mediate, in part, the association between personality risk and alcohol problems. Research suggests that trait impulsivity is associated with impaired control over alcohol; however, few studies of this association have included a range of impulsivity facets. The purpose of this study was to examine specific pathways from higher-order impulsivity factors to alcohol problems mediated via impaired control over alcohol. We also examined the moderating role of working memory in these associations. Young heavy drinkers (N=300) completed two multidimensional impulsivity measures (UPPS-P and BIS-11) along with self-report measures of impaired control over alcohol, alcohol use, and alcohol problems. Working memory was assessed using a computerized digit span task. Results showed that the impulsivity facets loaded onto two higher-order factors that were labeled response and reflection impulsivity. Response impulsivity predicted unique variance in self-reported impaired control and alcohol problems, whereas reflection impulsivity predicted unique variance in heavy drinking frequency only. Further, significant indirect associations were observed from response and reflection impulsivity to alcohol problems mediated via impaired control and heavy drinking frequency, respectively. Working memory and sensation seeking were not uniquely associated with the alcohol variables, and no support was found for the moderating role of working memory. The results help to clarify associations among impulsivity, impaired control, and alcohol problems, suggesting that impaired control may play a specific role in the pathway to alcohol problems from response impulsivity but not from reflection impulsivity. PMID:27269291

  10. Sliding mode direct power control of RSC for DFIGs driven by variable speed wind turbines

    Directory of Open Access Journals (Sweden)

    E.G. Shehata

    2015-12-01

    Full Text Available In spite of its several advantages, a classic direct power control (DPC of doubly fed induction generators (DFIGs driven by variable speed wind turbines has some drawbacks. In this paper, a simple and robust total sliding mode controller (TSMC is designed to improve the classical DPC performance without complicating the overall scheme. The TSMC is designed to regulate the DFIG stator active and reactive powers. Two integral switching functions are selected for describing the switching surfaces of the active and reactive powers. Reaching phase stability problem of the classical sliding mode controller is avoided in the proposed TSMC. Neither current control loops nor accurate values of machine parameters are required in the proposed scheme. In addition, axes transformation of the stator voltage and current are eliminated. The grid side converter is controlled based on DPC principle to regulate both DC-link voltage and total reactive power. The feasibility of the proposed DPC scheme is validated through simulation studies on a 1.5 MW wind power generation system. The performance of the proposed and conventional DPC schemes is compared under different operating conditions.

  11. Effect on energy use and greenhouse micro climate through fan motor control by variable frequency drives

    International Nuclear Information System (INIS)

    Teitel, Meir; Zhao Yun; Barak, Moti; Bar-lev, Eli; Shmuel, David

    2004-01-01

    A comparison was conducted between ON-OFF and variable frequency drive (VFD) systems to control greenhouse ventilation fans. The study aimed to determine the effect of each system on the energy consumption and resulting greenhouse micro climate. The experiments were conducted in a commercial size greenhouse in which pepper was grown. To check the performance of the fan that was controlled by a VFD system, it was installed in a test facility and operated under several rotation speeds. At each speed of rotation, the static pressure on the fan was changed and parameters, such as electricity consumption and air flow rate, were measured. Reducing the fan speed with the VFD system resulted in reductions in the air flow rate through the greenhouse and energy consumption, the latter being much more significant. The study showed that VFD control can reduce electricity consumption compared with ON-OFF operation by an amount that depends on the weather. In the present study, the average energy consumption with the VFD control system over a period of one month, was about 0.64 of that with an ON-OFF system. The average greenhouse daily air temperatures and humidity ratios obtained with each control system between 0700 and 1800 were nearly equal during that month. The results obtained in the greenhouse further show that the VFD system has a greater potential than the ON-OFF to reduce the range of amplitude variations in the air temperature and humidity ratio within the greenhouse

  12. Hybrid Vibration Control under Broadband Excitation and Variable Temperature Using Viscoelastic Neutralizer and Adaptive Feedforward Approach

    Directory of Open Access Journals (Sweden)

    João C. O. Marra

    2016-01-01

    Full Text Available Vibratory phenomena have always surrounded human life. The need for more knowledge and domain of such phenomena increases more and more, especially in the modern society where the human-machine integration becomes closer day after day. In that context, this work deals with the development and practical implementation of a hybrid (passive-active/adaptive vibration control system over a metallic beam excited by a broadband signal and under variable temperature, between 5 and 35°C. Since temperature variations affect directly and considerably the performance of the passive control system, composed of a viscoelastic dynamic vibration neutralizer (also called a viscoelastic dynamic vibration absorber, the associative strategy of using an active-adaptive vibration control system (based on a feedforward approach with the use of the FXLMS algorithm working together with the passive one has shown to be a good option to compensate the neutralizer loss of performance and generally maintain the extended overall level of vibration control. As an additional gain, the association of both vibration control systems (passive and active-adaptive has improved the attenuation of vibration levels. Some key steps matured over years of research on this experimental setup are presented in this paper.

  13. On the modelling and partial-load control of variable-speed wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Novak, P [Chalmers Univ. of Technology, Goeteborg (Sweden). School of Electrical and Computer Engineering

    1996-12-31

    The focus of this thesis is on modelling and variable-speed control of wind turbines. A physical model structure including the fundamental drive-train mode is derived and validated by system-identification experiments on a full-scale wind turbine. The resulting, parametrized model has been used as a basis for an evaluation of controllers for partial-load operation, validated by non-linear simulations. This evaluation, including several controller concepts, verifies that a sophisticated controller becomes necessary, when stretching the limits in power-loss minimization. This control strategy also demands the sampling frequency to be pushed to a high level. As a consequence, the angular-position measurements become time correlated and, in the limit, periodic. It is shown in the thesis how the resulting, operating-point-dependent effects on the measurement errors influence the estimation quality, using a stationary Kalman filter as an example. A gain-scheduling estimation approach is shown to improve the performance. 39 refs, 63 figs, 2 tabs

  14. Effect of endometrial biopsy on intrauterine insemination outcome in controlled ovarian stimulation cycle

    OpenAIRE

    Wadhwa, Leena; Pritam, Amrita; Gupta, Taru; Gupta, Sangeeta; Arora, Sarika; Chandoke, Rajkumar

    2015-01-01

    OBJECTIVE: The objective was to evaluate the effect of endometrial biopsy (EB) on intrauterine insemination (IUI) outcome in controlled ovarian stimulation (COS) cycle. DESIGN: Prospective randomized control study. SETTING: Tertiary care center. MATERIALS AND METHODS: A total of 251 subjects were enrolled in the study. Subjects undergoing COS with IUI were randomly allocated into three groups. Group A: EB was taken between D19 and 24 of the spontaneous menstrual cycles that precedes the ferti...

  15. Testing links between childhood positive peer relations and externalizing outcomes through a randomized controlled intervention study

    NARCIS (Netherlands)

    Witvliet, M.; van Lier, P.A.C.; Cuijpers, P.; Koot, H.M.

    2009-01-01

    In this study, the authors used a randomized controlled trial to explore the link between having positive peer relations and externalizing outcomes in 758 children followed from kindergarten to the end of 2nd grade. Children were randomly assigned to the Good Behavior Game (GBG), a universal

  16. Role Stress Revisited: Job Structuring Antecedents, Work Outcomes, and Moderating Effects of Locus of Control

    Science.gov (United States)

    Conley, Sharon; You, Sukkyung

    2014-01-01

    A previous study examined role stress in relation to work outcomes; in this study, we added job structuring antecedents to a model of role stress and examined the moderating effects of locus of control. Structural equation modeling was used to assess the plausibility of our conceptual model, which specified hypothesized linkages among teachers'…

  17. Stabilization of Networked Control Systems with Variable Delays and Saturating Inputs

    Directory of Open Access Journals (Sweden)

    M. Mahmodi Kaleybar

    2014-06-01

    Full Text Available In this paper, improved conditions for the synthesis of static state-feedback controller are derived to stabilize networked control systems (NCSs subject to actuator saturation. Both of the data packet latency and dropout which deteriorate the performance of the closed-loop system are considered in the NCS model via variable delays. Two different techniques are employed to incorporate actuator saturation in the system description. Utilizing Lyapunov-Krasovskii Theorem, delay-dependent conditions are obtained in terms of linear matrix inequalities (LMIs to determine the static feedback gain. Moreover, an optimization problem is formulated in order to find the less conservative estimate for the region of attraction corresponding to different maximum allowable delays. Numerical examples are introduced to demonstrate the effectiveness and advantages of the proposed schemes.

  18. The role of the control variable in the heuristically based generalized perturbation theory (HGPT)

    International Nuclear Information System (INIS)

    Gandini, A.

    1995-01-01

    The heuristically based generalized perturbation theory (HGPT) applied to the neutron field of a reactor system is discussed in relation to the criticality reset procedure. This procedure is implicit within the GPT methodology, corresponding to the so called filtering of the importance function relevant to the neutron field from the fundamental mode contamination. It is common practice to use the so called γ-mode filter. In order to account for any possible reset option, a general definition is introduced of an intensive control variable (ρ) entering into the governing equations, and correspondingly a fundamental ρ-mode filtering of the importance function is defined, relevant to the real criticality reset mechanism (control) adopted. A simple example illustrates the need in many circumstances of interest of taking into proper account the correct filtering so to avoid significant inaccuracies in the sensitivity calculation results

  19. Adaptive variable structure control for uncertain chaotic systems containing dead-zone nonlinearity

    International Nuclear Information System (INIS)

    Yan, J.-J.; Shyu, K.-K.; Lin, J.-S.

    2005-01-01

    This paper addresses a practical tracking problem for a class of uncertain chaotic systems with dead-zone nonlinearity in the input function. Based on the Lyapunov stability theorem and Barbalat lemma, an adaptive variable structure controller (AVSC) is proposed to ensure the occurrence of the sliding mode even though the control input contains a dead-zone. Also it is worthy of note that the proposed AVSC involves no information of the upper bound of uncertainty. Thus, the limitation of knowing the bound of uncertainty in advance is certainly released. Furthermore, in the sliding mode, the investigated uncertain chaotic system remains insensitive to the uncertainty, and behaves like a linear system. Finally, a well-known Duffing-Holmes chaotic system is used to demonstrate the feasibility of the proposed AVSC

  20. [Metabolic control in the critically ill patient an update: hyperglycemia, glucose variability hypoglycemia and relative hypoglycemia].

    Science.gov (United States)

    Pérez-Calatayud, Ángel Augusto; Guillén-Vidaña, Ariadna; Fraire-Félix, Irving Santiago; Anica-Malagón, Eduardo Daniel; Briones Garduño, Jesús Carlos; Carrillo-Esper, Raúl

    Metabolic changes of glucose in critically ill patients increase morbidity and mortality. The appropriate level of blood glucose has not been established so far and should be adjusted for different populations. However concepts such as glucose variability and relative hypoglycemia of critically ill patients are concepts that are changing management methods and achieving closer monitoring. The purpose of this review is to present new data about the management and metabolic control of patients in critical areas. Currently glucose can no longer be regarded as an innocent element in critical patients; both hyperglycemia and hypoglycemia increase morbidity and mortality of patients. Protocols and better instruments for continuous measurement are necessary to achieve the metabolic control of our patients. Copyright © 2016 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

  1. Searching for the variables that control human rule-governed "insensitivity".

    Science.gov (United States)

    Fox, Adam E; Kyonka, Elizabeth G E

    2017-09-01

    Verbal rules or instructions often exert obvious and meaningful control over human behavior. Sometimes instructions benefit the individual by enabling faster acquisition of a skill or by obviating an aversive consequence. However, research has also suggested a clear disadvantage: "insensitivity" to changing underlying contingencies. The two experiments described here investigated the variables that control initial rule-following behavior and rule-following insensitivity. When the initial rule was inaccurate, behavior was consistent with the rule for approximately half of participants and all participants' behavior was mostly insensitive to changing contingencies. When the initial rule was accurate, behavior of all participants was consistent with it and behavior for nearly all participants was insensitive to changes in underlying contingencies. These findings have implications for how best to establish and maintain rule-following behavior in applied settings when deviant behavior would be more reinforcing to the individual. © 2017 Society for the Experimental Analysis of Behavior.

  2. Climate variability and vadose zone controls on damping of transient recharge

    Science.gov (United States)

    Corona, Claudia R.; Gurdak, Jason J.; Dickinson, Jesse; Ferré, T.P.A.; Maurer, Edwin P.

    2017-01-01

    Increasing demand on groundwater resources motivates understanding of the controls on recharge dynamics so model predictions under current and future climate may improve. Here we address questions about the nonlinear behavior of flux variability in the vadose zone that may explain previously reported teleconnections between global-scale climate variability and fluctuations in groundwater levels. We use hundreds of HYDRUS-1D simulations in a sensitivity analysis approach to evaluate the damping depth of transient recharge over a range of periodic boundary conditions and vadose zone geometries and hydraulic parameters that are representative of aquifer systems of the conterminous United States (U.S). Although the models were parameterized based on U.S. aquifers, findings from this study are applicable elsewhere that have mean recharge rates between 3.65 and 730 mm yr–1. We find that mean infiltration flux, period of time varying infiltration, and hydraulic conductivity are statistically significant predictors of damping depth. The resulting framework explains why some periodic infiltration fluxes associated with climate variability dampen with depth in the vadose zone, resulting in steady-state recharge, while other periodic surface fluxes do not dampen with depth, resulting in transient recharge. We find that transient recharge in response to the climate variability patterns could be detected at the depths of water levels in most U.S. aquifers. Our findings indicate that the damping behavior of transient infiltration fluxes is linear across soil layers for a range of texture combinations. The implications are that relatively simple, homogeneous models of the vadose zone may provide reasonable estimates of the damping depth of climate-varying transient recharge in some complex, layered vadose zone profiles.

  3. CHARACTERISTIC OF PARAMETERS OF HEART RATE VARIABILITY IN PATIENTS WITH DIFFICULT-TO-CONTROL AND CONTROLLED ARTERIAL HYPERTENSION

    Directory of Open Access Journals (Sweden)

    Tymoshenko O. S.

    2017-12-01

    Full Text Available Parameters of heart rate variability (HRV were studied in 112 patients with arterial hypertension (AH aged 58.5 ± 9 years (60 patients with difficult-to-control arterial hypertension (DTCAH and 52 patients with controlled arterial hypertension (CAH. The control group was consisted of 20 conditionally healthy persons of the same sex and age. It has been established that patients with AH were characterized by decrease in the level of total power of the HRV spectrum, the power of the high-frequency (HF and low-frequency (LF domains of the spectrum, and increase in the level of the very low-frequency spectrum (VLF and value LF/HF that reflect sympathovagal balance. It has been established that there were more significant disorders in neurohumoral regulation in patients with DTCAH in comparison with patients with CAH, which consist of the predominant adrenergic activation, primarily due to the sympathetic link of the autonomic nervous system. HRV can be used as an effective non-invasive method for the diagnosis and control of DTCAH.

  4. Patterns and controls of inter-annual variability in the terrestrial carbon budget

    Directory of Open Access Journals (Sweden)

    B. Marcolla

    2017-08-01

    Full Text Available The terrestrial carbon fluxes show the largest variability among the components of the global carbon cycle and drive most of the temporal variations in the growth rate of atmospheric CO2. Understanding the environmental controls and trends of the terrestrial carbon budget is therefore essential to predict the future trajectories of the CO2 airborne fraction and atmospheric concentrations. In the present work, patterns and controls of the inter-annual variability (IAV of carbon net ecosystem exchange (NEE have been analysed using three different data streams: ecosystem-level observations from the FLUXNET database (La Thuile and 2015 releases, the MPI-MTE (model tree ensemble bottom–up product resulting from the global upscaling of site-level fluxes, and the Jena CarboScope Inversion, a top–down estimate of surface fluxes obtained from observed CO2 concentrations and an atmospheric transport model. Consistencies and discrepancies in the temporal and spatial patterns and in the climatic and physiological controls of IAV were investigated between the three data sources. Results show that the global average of IAV at FLUXNET sites, quantified as the standard deviation of annual NEE, peaks in arid ecosystems and amounts to  ∼  120 gC m−2 y−1, almost 6 times more than the values calculated from the two global products (15 and 20 gC m−2 y−1 for MPI-MTE and the Jena Inversion, respectively. Most of the temporal variability observed in the last three decades of the MPI-MTE and Jena Inversion products is due to yearly anomalies, whereas the temporal trends explain only about 15 and 20 % of the variability, respectively. Both at the site level and on a global scale, the IAV of NEE is driven by the gross primary productivity and in particular by the cumulative carbon flux during the months when land acts as a sink. Altogether these results offer a broad view on the magnitude, spatial patterns and environmental drivers of IAV

  5. Patterns and controls of inter-annual variability in the terrestrial carbon budget

    Science.gov (United States)

    Marcolla, Barbara; Rödenbeck, Christian; Cescatti, Alessandro

    2017-08-01

    The terrestrial carbon fluxes show the largest variability among the components of the global carbon cycle and drive most of the temporal variations in the growth rate of atmospheric CO2. Understanding the environmental controls and trends of the terrestrial carbon budget is therefore essential to predict the future trajectories of the CO2 airborne fraction and atmospheric concentrations. In the present work, patterns and controls of the inter-annual variability (IAV) of carbon net ecosystem exchange (NEE) have been analysed using three different data streams: ecosystem-level observations from the FLUXNET database (La Thuile and 2015 releases), the MPI-MTE (model tree ensemble) bottom-up product resulting from the global upscaling of site-level fluxes, and the Jena CarboScope Inversion, a top-down estimate of surface fluxes obtained from observed CO2 concentrations and an atmospheric transport model. Consistencies and discrepancies in the temporal and spatial patterns and in the climatic and physiological controls of IAV were investigated between the three data sources. Results show that the global average of IAV at FLUXNET sites, quantified as the standard deviation of annual NEE, peaks in arid ecosystems and amounts to ˜ 120 gC m-2 y-1, almost 6 times more than the values calculated from the two global products (15 and 20 gC m-2 y-1 for MPI-MTE and the Jena Inversion, respectively). Most of the temporal variability observed in the last three decades of the MPI-MTE and Jena Inversion products is due to yearly anomalies, whereas the temporal trends explain only about 15 and 20 % of the variability, respectively. Both at the site level and on a global scale, the IAV of NEE is driven by the gross primary productivity and in particular by the cumulative carbon flux during the months when land acts as a sink. Altogether these results offer a broad view on the magnitude, spatial patterns and environmental drivers of IAV from a variety of data sources that can be

  6. [Predictors of mean blood glucose control and its variability in diabetic hospitalized patients].

    Science.gov (United States)

    Sáenz-Abad, Daniel; Gimeno-Orna, José Antonio; Sierra-Bergua, Beatriz; Pérez-Calvo, Juan Ignacio

    2015-01-01

    This study was intended to assess the effectiveness and predictors factors of inpatient blood glucose control in diabetic patients admitted to medical departments. A retrospective, analytical cohort study was conducted on patients discharged from internal medicine with a diagnosis related to diabetes. Variables collected included demographic characteristics, clinical data and laboratory parameters related to blood glucose control (HbA1c, basal plasma glucose, point-of-care capillary glucose). The cumulative probability of receiving scheduled insulin regimens was evaluated using Kaplan-Meier analysis. Multivariate regression models were used to select predictors of mean inpatient glucose (MHG) and glucose variability (standard deviation [GV]). The study sample consisted of 228 patients (mean age 78.4 (SD 10.1) years, 51% women). Of these, 96 patients (42.1%) were treated with sliding-scale regular insulin only. Median time to start of scheduled insulin therapy was 4 (95% CI, 2-6) days. Blood glucose control measures were: MIG 181.4 (SD 41.7) mg/dL, GV 56.3 (SD 22.6). The best model to predict MIG (R(2): .376; P<.0001) included HbA1c (b=4.96; P=.011), baseline plasma glucose (b=.056; P=.084), mean capillary blood glucose in the first 24hours (b=.154; P<.0001), home treatment (versus oral agents) with basal insulin only (b=13.1; P=.016) or more complex (pre-mixed insulin or basal-bolus) regimens (b=19.1; P=.004), corticoid therapy (b=14.9; P=.002), and fasting on admission (b=10.4; P=.098). Predictors of inpatient blood glucose control which should be considered in the design of DM management protocols include home treatment, HbA1c, basal plasma glucose, mean blood glucose in the first 24hours, fasting, and corticoid therapy. Copyright © 2014 SEEN. Published by Elsevier España, S.L.U. All rights reserved.

  7. Panel Management to Improve Smoking and Hypertension Outcomes by VA Primary Care Teams: A Cluster-Randomized Controlled Trial.

    Science.gov (United States)

    Schwartz, Mark D; Jensen, Ashley; Wang, Binhuan; Bennett, Katelyn; Dembitzer, Anne; Strauss, Shiela; Schoenthaler, Antoinette; Gillespie, Colleen; Sherman, Scott

    2015-07-01

    Panel Management can expand prevention and chronic illness management beyond the office visit, but there is limited evidence for its effectiveness or guidance on how best to incorporate it into practice. We aimed to test the effectiveness of incorporating panel management into clinical practice by incorporating Panel Management Assistants (PMAs) into primary care teams with and without panel management education. We conducted an 8-month cluster-randomized controlled trial of panel management for improving hypertension and smoking cessation outcomes among veterans. Twenty primary care teams from the Veterans Affairs New York Harbor were randomized to control, panel management support, or panel management support plus education groups. Teams included 69 clinical staff serving 8,153 hypertensive and/or smoking veterans. Teams assigned to the intervention groups worked with non-clinical Panel Management Assistants (PMAs) who monitored care gaps and conducted proactive patient outreach, including referrals, mail reminders and motivational interviewing by telephone. Measurements included mean systolic and diastolic blood pressure, proportion of patients with controlled blood pressure, self-reported quit attempts, nicotine replacement therapy (NRT) prescriptions, and referrals to disease management services. Change in mean blood pressure, blood pressure control, and smoking quit rates were similar across study groups. Patients on intervention teams were more likely to receive NRT (OR = 1.4; 95% CI 1.2-1.6) and enroll in the disease management services MOVE! (OR = 1.2; 95% CI 1.1-1.6) and Telehealth (OR = 1.7, 95% CI 1.4-2.1) than patients on control teams. Panel Management support for primary care teams improved process, but not outcome variables among veterans with hypertension and smoking. Incorporating PMAs into teams was feasible and highly valued by the clinical staff, but clinical impact may require a longer intervention.

  8. Monitoring the quality of cardiac surgery based on three or more surgical outcomes using a new variable life-adjusted display.

    Science.gov (United States)

    Gan, Fah Fatt; Tang, Xu; Zhu, Yexin; Lim, Puay Weng

    2017-06-01

    The traditional variable life-adjusted display (VLAD) is a graphical display of the difference between expected and actual cumulative deaths. The VLAD assumes binary outcomes: death within 30 days of an operation or survival beyond 30 days. Full recovery and bedridden for life, for example, are considered the same outcome. This binary classification results in a great loss of information. Although there are many grades of survival, the binary outcomes are commonly used to classify surgical outcomes. Consequently, quality monitoring procedures are developed based on binary outcomes. With a more refined set of outcomes, the sensitivities of these procedures can be expected to improve. A likelihood ratio method is used to define a penalty-reward scoring system based on three or more surgical outcomes for the new VLAD. The likelihood ratio statistic W is based on testing the odds ratio of cumulative probabilities of recovery R. Two methods of implementing the new VLAD are proposed. We accumulate the statistic W-W¯R to estimate the performance of a surgeon where W¯R is the average of the W's of a historical data set. The accumulated sum will be zero based on the historical data set. This ensures that if a new VLAD is plotted for a future surgeon of performance similar to this average performance, the plot will exhibit a horizontal trend. For illustration of the new VLAD, we consider 3-outcome surgical results: death within 30 days, partial and full recoveries. In our first illustration, we show the effect of partial recoveries on surgical results of a surgeon. In our second and third illustrations, the surgical results of two surgeons are compared using both the traditional VLAD based on binary-outcome data and the new VLAD based on 3-outcome data. A reversal in relative performance of surgeons is observed when the new VLAD is used. In our final illustration, we display the surgical results of four surgeons using the new VLAD based completely on 3-outcome data. Full

  9. Variability in Management of Acute Osteoarticular Infections at a Children’s Hospital and Favorable Outcomes with Increasing Early Transition to Oral Therapy

    OpenAIRE

    Biary, Nora; Wrotniak, Brian; Islam, Shamim

    2017-01-01

    Abstract Background To date, there is no established guideline for the treatment of acute pediatric osteoarticular infections (OAI), and considerable variability in management exists amongst providers and across institutions. This study analyzed the recent management and clinical outcomes of OAI at a children’s hospital. Methods Patients admitted with acute osteomyelitis and septic arthritis [OAI] aged 2 months to 18 years at the Women & Children’s Hospital of Buffalo, between 1/1/2013 and 12...

  10. Modeling tumor control probability for spatially inhomogeneous risk of failure based on clinical outcome data

    DEFF Research Database (Denmark)

    Lühr, Armin; Löck, Steffen; Jakobi, Annika

    2017-01-01

    PURPOSE: Objectives of this work are (1) to derive a general clinically relevant approach to model tumor control probability (TCP) for spatially variable risk of failure and (2) to demonstrate its applicability by estimating TCP for patients planned for photon and proton irradiation. METHODS AND ...

  11. Voltage control of a variable speed wind turbine connected to an isolated load: Experimental study

    International Nuclear Information System (INIS)

    Masmoudi, Abdelkarim; Krichen, Lotfi; Ouali, Abderrazak

    2012-01-01

    Highlights: ► We develop an experimental test bench of a wind energy conversion system. ► A DC motor is emulating a variable speed wind turbine using a DS1104 card. ► The production unit is supplying a three-phase load. ► A voltage control is established in order to regulate the DC bus voltage and the line-to-line voltages. - Abstract: This study is interested in the development of an experimental test bench of an autonomous wind energy conversion system (WECS) based on a permanent magnet synchronous generator (PMSG). After the description of the test bench, the elements constituting the WECS are presented. Then, a real time model implemented under a digital signal processor (DSP) system is established. The first objective of this work is to validate the functionality of the test bench leading to experiment some principles developed in theory. The second objective is to control the load connection voltages and the DC bus voltage. For the first control, two resonant controllers are used and for the second one, a dump load, connected to the DC bus, offers the possibility to maintain a balance between production and consumption in spite of wind fluctuations and load variations. The experimental results show the effectiveness of the test bench trying out in real time the behavior of a WECS supplying an isolated load.

  12. Variable Parameter Nonlinear Control for Maximum Power Point Tracking Considering Mitigation of Drive-train Load

    Institute of Scientific and Technical Information of China (English)

    Zaiyu; Chen; Minghui; Yin; Lianjun; Zhou; Yaping; Xia; Jiankun; Liu; Yun; Zou

    2017-01-01

    Since mechanical loads exert a significant influence on the life span of wind turbines, the reduction of transient load on drive-train shaft has received more attention when implementing a maximum power point tracking(MPPT) controller.Moreover, a trade-off between the efficiency of wind energy extraction and the load level of drive-train shaft becomes a key issue. However, for the existing control strategies based on nonlinear model of wind turbines, the MPPT efficiencies are improved at the cost of the intensive fluctuation of generator torque and significant increase of transient load on drive train shaft. Hence, in this paper, a nonlinear controller with variable parameter is proposed for improving MPPT efficiency and mitigating transient load on drive-train simultaneously. Then,simulations on FAST(Fatigue, Aerodynamics, Structures, and Turbulence) code and experiments on the wind turbine simulator(WTS) based test bench are presented to verify the efficiency improvement of the proposed control strategy with less cost of drive-train load.

  13. Variable Parameter Nonlinear Control for Maximum Power Point Tracking Considering Mitigation of Drive-train Load

    Institute of Scientific and Technical Information of China (English)

    Zaiyu Chen; Minghui Yin; Lianjun Zhou; Yaping Xia; Jiankun Liu; Yun Zou

    2017-01-01

    Since mechanical loads exert a significant influence on the life span of wind turbines,the reduction of transient load on drive-train shaft has received more attention when implementing a maximum power point tracking (MPPT) controller.Moreover,a trade-off between the efficiency of wind energy extraction and the load level of drive-train shaft becomes a key issue.However,for the existing control strategies based on nonlinear model of wind turbines,the MPPT efficiencies are improved at the cost of the intensive fluctuation of generator torque and significant increase of transient load on drive train shaft.Hence,in this paper,a nonlinear controller with variable parameter is proposed for improving MPPT efficiency and mitigating transient load on drive-train simultaneously.Then,simulations on FAST (Fatigue,Aerodynamics,Structures,and Turbulence) code and experiments on the wind turbine simulator (WTS) based test bench are presented to verify the efficiency improvement of the proposed control strategy with less cost of drive-train load.

  14. Shamba Maisha: randomized controlled trial of an agricultural and finance intervention to improve HIV health outcomes.

    Science.gov (United States)

    Weiser, Sheri D; Bukusi, Elizabeth A; Steinfeld, Rachel L; Frongillo, Edward A; Weke, Elly; Dworkin, Shari L; Pusateri, Kyle; Shiboski, Stephen; Scow, Kate; Butler, Lisa M; Cohen, Craig R

    2015-09-10

    Food insecurity and HIV/AIDS outcomes are inextricably linked in sub-Saharan Africa. We report on health and nutritional outcomes of a multisectoral agricultural intervention trial among HIV-infected adults in rural Kenya. This is a pilot cluster randomized controlled trial. The intervention included a human-powered water pump, a microfinance loan to purchase farm commodities, and education in sustainable farming practices and financial management. Two health facilities in Nyanza Region, Kenya were randomly assigned as intervention or control. HIV-infected adults 18 to 49 years' old who were on antiretroviral therapy and had access to surface water and land were enrolled beginning in April 2012 and followed quarterly for 1 year. Data were collected on nutritional parameters, CD4 T-lymphocyte counts, and HIV RNA. Differences in fixed-effects regression models were used to test whether patterns in health outcomes differed over time from baseline between the intervention and control arms. We enrolled 72 and 68 participants in the intervention and control groups, respectively. At 12 months follow-up, we found a statistically significant increase in CD4 cell counts (165 cells/μl, P security (3.6 scale points higher, P < 0.001) and frequency of food consumption (9.4 times per week greater frequency, P = 0.013) compared to controls. Livelihood interventions may be a promising approach to tackle the intersecting problems of food insecurity, poverty and HIV/AIDS morbidity.

  15. Choice and Outcomes of Rate Control versus Rhythm Control in Elderly Patients with Atrial Fibrillation

    DEFF Research Database (Denmark)

    Paciullo, Francesco; Proietti, Marco; Bianconi, Vanessa

    2018-01-01

    BACKGROUND: Among rate-control or rhythm-control strategies, there is conflicting evidence as to which is the best management approach for non-valvular atrial fibrillation (AF) in elderly patients. DESIGN: We performed an ancillary analysis from the 'Registro Politerapie SIMI' study, enrolling el...

  16. Psychosocial outcome and psychiatric comorbidity in older adolescents with Tourette syndrome: controlled study.

    Science.gov (United States)

    Gorman, Daniel A; Thompson, Nancy; Plessen, Kerstin J; Robertson, Mary M; Leckman, James F; Peterson, Bradley S

    2010-07-01

    Children with Tourette syndrome generally experience improvement of tics by age 18 years, but psychosocial and comorbidity outcomes at this age are unclear. To compare psychosocial outcomes and lifetime comorbidity rates in older adolescents with Tourette syndrome and controls. We hypothesised a priori that individuals with Tourette syndrome would have lower Children's Global Assessment Scale (CGAS) scores. A total of 65 individuals with Tourette syndrome, identified in childhood, and 65 matched community controls without tic or obsessive-compulsive disorder (OCD) symptoms were assessed around 18 years of age regarding psychosocial functioning and lifetime psychiatric disorders. Compared with controls, individuals with Tourette syndrome had substantially lower CGAS scores (P = 10(-8)) and higher rates of attention-deficit hyperactivity disorder (ADHD), major depression, learning disorder and conduct disorder (Ptic severity. Clinically ascertained children with Tourette syndrome typically have impaired psychosocial functioning and high comorbidity rates in late adolescence.

  17. Mitochondrial DNA control region variability in wild boars from west Balkans

    Directory of Open Access Journals (Sweden)

    Đan Mihajla

    2013-01-01

    Full Text Available The wild boar (Sus scrofa is one of most abundant game species in hunting areas of Balkan region. The large fraction of pre-glacial genetic diversity in wild boar populations from the Balkans was addressed due to high proportion of unique mtDNA haplotypes found in Greece, indicating Balkan as main refugial area for wild boars. The aim of the present study is to characterize mitochondrial DNA control region variability in wild boars from different areas in the West Balkan region, in order to evaluate level of genetic variability, to detect unique haplotypes and to infer possible structuring. The total number of 163 individuals from different sampling localities were included in the study. A fragment of the mtDNA control region was amplified and sequenced by standard procedures. Population genetic analyses were performed using several computer packages: BioEdit, ARLEQUIN 3.5.1.2., Network 4.6.0.0 and MEGA5. Eleven different haplotypes were identified and haplotype diversity was 0.676, nucleotide diversity 0.0026, and the average number of nucleotide differences (k 1.169. The mismatch distribution and neutrality tests indicated the expansion of the all populations. It is shown that high level of genetic diversity is present in the wild boars from the West Balkan region and we have managed to detect regional unique haplotypes in high frequency. Genetic diversity differences have been found in regional wild boar groups, clustering them in two main clusters, but further speculations on the reasons for the observed clustering are prevented due to restricted informativness of the single locus marker. Obtained knowledge of genetic variation in the wild boar may be relevant for improving knowledge of the phylogeny and phylogeography of the wild boars, but as well as for hunting societies and responsible authorities for the effective control of wild boar populations.

  18. OUTCOMES OF HILAR PEDICLE CONTROL USING SUTURE LIGATION DURING LAPAROSCOPIC SPLENECTOMY.

    Science.gov (United States)

    Makgoka, M

    2017-06-01

    Laparoscopic splenectomy is a well described gold standard procedure for various indications. One of the key steps during laparoscopic splenectomy is the hilar pedicle vessels control, which can be challenging in most cases. Most centres around the world recommend the use Ligaclib or endovascular staplers as Methods of choice for hilar pedicle control but the issue is the cost and efficiency of the laparoscopic haemostatic devices. A descriptive retrospective study of patients who had laparoscopic splenectomy from 2013 to present. Hilar splenic vessel control was done with suture ligation. We looked at outcomes of patients offered this technique, complications of this technique, and describing the technique of hilar control in laparoscopic splenectomy. Total of 27 patients had laparoscopic splenectomy with splenic hilar pedicle control with suture ligation. Mean operative time, mean blood volume loss, length of hospital stay, postoperative complications conversion to laparotomy. Laparoscopic hilar pedicle control with suture ligation is safe and effective for the patient in our hospital setting.

  19. Ensemble survival tree models to reveal pairwise interactions of variables with time-to-events outcomes in low-dimensional setting

    Science.gov (United States)

    Dazard, Jean-Eudes; Ishwaran, Hemant; Mehlotra, Rajeev; Weinberg, Aaron; Zimmerman, Peter

    2018-01-01

    Unraveling interactions among variables such as genetic, clinical, demographic and environmental factors is essential to understand the development of common and complex diseases. To increase the power to detect such variables interactions associated with clinical time-to-events outcomes, we borrowed established concepts from random survival forest (RSF) models. We introduce a novel RSF-based pairwise interaction estimator and derive a randomization method with bootstrap confidence intervals for inferring interaction significance. Using various linear and nonlinear time-to-events survival models in simulation studies, we first show the efficiency of our approach: true pairwise interaction-effects between variables are uncovered, while they may not be accompanied with their corresponding main-effects, and may not be detected by standard semi-parametric regression modeling and test statistics used in survival analysis. Moreover, using a RSF-based cross-validation scheme for generating prediction estimators, we show that informative predictors may be inferred. We applied our approach to an HIV cohort study recording key host gene polymorphisms and their association with HIV change of tropism or AIDS progression. Altogether, this shows how linear or nonlinear pairwise statistical interactions of variables may be efficiently detected with a predictive value in observational studies with time-to-event outcomes. PMID:29453930

  20. Magnetic resonance observation of cartilage repair tissue (MOCART) for the evaluation of autologous chondrocyte transplantation: Determination of interobserver variability and correlation to clinical outcome after 2 years

    International Nuclear Information System (INIS)

    Marlovits, Stefan; Singer, Philipp; Zeller, Philip; Mandl, Irena; Haller, Joerg; Trattnig, Siegfried

    2006-01-01

    In an observational study, the validity and reliability of magnetic resonance imaging (MRI) for the assessment of autologous chondrocyte transplantation (ACT) in the knee joint was determined. Two years after implantation, high-resolution MRI was used to analyze the repair tissue with nine pertinent variables. A complete filling of the defect was found in 61.5%, and a complete integration of the border zone to the adjacent cartilage in 76.9%. An intact subchondral lamina was present in 84.6% and an intact subchondral bone was present in 61.5%. Isointense signal intensities of the repair tissue compared to the adjacent native cartilage were seen in 92.3%. To evaluate interobserver variability, a reliability analysis with the determination of the intraclass correlation coefficient (ICC) was calculated. An 'almost perfect' agreement, with an ICC value >0.81, was calculated in 8 of 9 variables. The clinical outcome after 2 years showed the visual analog score (VAS) at 2.62 (S.D. ±0.65). The values for the knee injury and osteoarthritis outcome score (KOOS) subgroups were 68.29 (±23.90) for pain, 62.09 (±14.62) for symptoms, 75.45 (±21.91) for ADL function, 52.69 (±28.77) for sport and 70.19 (±22.41) for knee-related quality of life. The clinical scores were correlated with the MRI variables. A statistically significant correlation was found for the variables 'filling of the defect,' 'structure of the repair tissue,' 'changes in the subchondral bone,' and 'signal intensities of the repair issue'. High resolution MRI and well-defined MRI variables are a reliable, reproducible and accurate tool for assessing cartilage repair tissue

  1. Magnetic resonance observation of cartilage repair tissue (MOCART) for the evaluation of autologous chondrocyte transplantation: Determination of interobserver variability and correlation to clinical outcome after 2 years

    Energy Technology Data Exchange (ETDEWEB)

    Marlovits, Stefan [Department of Traumatology, Center for Joint and Cartilage, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria)]. E-mail: stefan.marlovits@meduniwien.ac.at; Singer, Philipp [Department of Traumatology, Center for Joint and Cartilage, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Zeller, Philip [Department of Traumatology, Center for Joint and Cartilage, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Mandl, Irena [Department of Traumatology, Center for Joint and Cartilage, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Haller, Joerg [Department of Radiology, Hanusch Hospital, Heinrich-Collin-Strasse, A-1140 Vienna (Austria); Trattnig, Siegfried [Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria)

    2006-01-15

    In an observational study, the validity and reliability of magnetic resonance imaging (MRI) for the assessment of autologous chondrocyte transplantation (ACT) in the knee joint was determined. Two years after implantation, high-resolution MRI was used to analyze the repair tissue with nine pertinent variables. A complete filling of the defect was found in 61.5%, and a complete integration of the border zone to the adjacent cartilage in 76.9%. An intact subchondral lamina was present in 84.6% and an intact subchondral bone was present in 61.5%. Isointense signal intensities of the repair tissue compared to the adjacent native cartilage were seen in 92.3%. To evaluate interobserver variability, a reliability analysis with the determination of the intraclass correlation coefficient (ICC) was calculated. An 'almost perfect' agreement, with an ICC value >0.81, was calculated in 8 of 9 variables. The clinical outcome after 2 years showed the visual analog score (VAS) at 2.62 (S.D. {+-}0.65). The values for the knee injury and osteoarthritis outcome score (KOOS) subgroups were 68.29 ({+-}23.90) for pain, 62.09 ({+-}14.62) for symptoms, 75.45 ({+-}21.91) for ADL function, 52.69 ({+-}28.77) for sport and 70.19 ({+-}22.41) for knee-related quality of life. The clinical scores were correlated with the MRI variables. A statistically significant correlation was found for the variables 'filling of the defect,' 'structure of the repair tissue,' 'changes in the subchondral bone,' and 'signal intensities of the repair issue'. High resolution MRI and well-defined MRI variables are a reliable, reproducible and accurate tool for assessing cartilage repair tissue.

  2. Perfiles de organizaciones positivas. Análisis de características percibidas según variables individuales, organizacionales y de resultado (Positive organization profiles. Analysis of perceived characteristics according to individual, organizational, and outcome variables

    Directory of Open Access Journals (Sweden)

    María Laura Lupano Perugini

    2016-08-01

    Full Text Available This study analysed the profiles of organizations based on employee perceptions of their workplace. The sample consisted of 459 Argentinian employees (232 men; average age, 36.3 years (SD = 11.7. The participants worked for public companies (17.2%, n = 79 or private companies (82.6%, n = 379. Most of them lived in Buenos Aires and surrounding areas (96.5%, n = 443. A protocol was used for data collection, in which the participants were asked to report positive and negative characteristics associated with their organization. A content analysis of the answers given by the participants was performed, from which different categories of characteristics were derived (e.g., work climate, commitment, values. Several multiple correspondence analyses were conducted to generate profiles according to individual variables (i.e., gender, age, and position, organizational variables (i.e., size, typology, and type, and outcome variables (i.e., performance and job satisfaction. One of the most significant profiles showed associations between the perception of positive characteristics, such as values and outcomes, and high levels of satisfaction and individual/organizational performance.

  3. Depression, anxiety, and heart rate variability: A case-control study in Taiwan

    Directory of Open Access Journals (Sweden)

    Li-Fen Chen

    2014-01-01

    Full Text Available Objective: Decreased heart rate variability (HRV has been reported in persons with major depressive disorder (MDD, but the results obtained are inconsistent. Little is known about the impact of comorbid anxiety disorders on HRV in MDD patients. Both issues necessitate further investigation. Materials and Methods: Forty-nine unmedicated, physically healthy, MDD patients without comorbidity, 21 MDD patients with comorbid generalized anxiety disorder (GAD, 24 MDD patients with comorbid panic disorder (PD, and 81 matched controls were recruited. The Hamilton Depression Rating Scale and the Hamilton Anxiety Rating Scale are employed to assess the severity of depression and anxiety, respectively. The cardiac autonomic function was evaluated by measuring the HRV parameters. The frequency-domain indices of HRV were obtained. Results: MDD patients without comorbidity had lower high-frequency (HF-HRV (which reflected vagal control of HRV than controls. Any comorbid anxiety disorder (GAD or PD was associated with significantly faster heart rates, relative to the controls, and caused greater reductions in HF-HRV among MDD patients. MDD participants with comorbid GAD displayed the greatest reductions in HF-HRV, relative to controls. Correlation analyses revealed that the severity of both depression and anxiety were significantly associated with the mean R wave to R wave (R-R intervals, variance, low-frequency (LF-HRV, and HF-HRV. Conclusion: The present results show decreased HRV in MDD patients, suggesting that reduction in HRV is a psychophysiological marker of MDD. MDD patients with comorbid GAD had the greatest reductions in HRV. Further investigation of the links between MDD and comorbid GAD, HRV, and cardiovascular disease is warranted.

  4. Tip Speed Ratio Based Maximum Power Tracking Control of Variable Speed Wind Turbines; A Comprehensive Design

    Directory of Open Access Journals (Sweden)

    Murat Karabacak

    2017-08-01

    Full Text Available The most primitive control method of wind turbines used to generate electric energy from wind is the fixed speed control method. With this method, it is not possible that turbine input power is transferred to grid at maximum rate. For this reason, Maximum Power Tracking (MPT schemes are proposed. In order to implement MPT, the propeller has to rotate at a different speed for every different wind speed. This situation has led MPT based systems to be called Variable Speed Wind Turbine (VSWT systems. In VSWT systems, turbine input power can be transferred to grid at rates close to maximum power. When MPT based control of VSWT systems is the case, two important processes come into prominence. These are instantaneously determination and tracking of MPT point. In this study, using a Maximum Power Point Tracking (MPPT method based on tip speed ratio, power available in wind is transferred into grid over a back to back converter at maximum rate via a VSWT system with permanent magnet synchronous generator (PMSG. Besides a physical wind turbine simulator is modelled and simulated. Results show that a time varying MPPT point is tracked with a high performance.

  5. Temperature and pH Responsive Microfibers for Controllable and Variable Ibuprofen Delivery

    Directory of Open Access Journals (Sweden)

    Toan Tran

    2015-01-01

    Full Text Available Electrospun microfibers (MFs composed of pH and temperature responsive polymers can be used for controllable and variable delivery of ibuprofen. First, electrospinning technique was employed to prepare poly(ε-caprolactone (PCL and poly(N-isopropylacrylamide-co-methacrylic acid (pNIPAM-co-MAA MFs containing ibuprofen. It was found that drug release rates from PCL MFs cannot be significantly varied by either temperature (22–40°C or pH values (1.7–7.4. In contrast, the ibuprofen (IP diffusion rates from pNIPAM-co-MAA MFs were very sensitive to changes in both temperature and pH. The IP release from pNIPAM-co-MAA MFs was highly linear and controllable when the temperature was above the lower critical solution temperature (LCST of pNIPAM-co-MAA (33°C and the pH was lower than the pKa of carboxylic acids (pH 2. At room temperature, however, the release rate was dramatically increased by nearly ten times compared to that at higher temperature and lower pH. Such a unique and controllable drug delivery system could be naturally envisioned to find many practical applications in biomedical and pharmaceutical sciences such as programmable transdermal drug delivery.

  6. LED Current Balance Using a Variable Voltage Regulator with Low Dropout vDS Control

    Directory of Open Access Journals (Sweden)

    Hung-I Hsieh

    2017-02-01

    Full Text Available A cost-effective light-emitting diode (LED current balance strategy using a variable voltage regulator (VVR with low dropout vDS control is proposed. This can regulate the multiple metal-oxide-semiconductor field-effect transistors (MOSFETs of the linear current regulators (LCR, maintaining low dropout vDS on the flat vGS-characteristic curves and making all drain currents almost the same. Simple group LCRs respectively loaded with a string LED are employed to implement the theme. The voltage VVdc from a VVR is synthesized by a string LED voltage NvD, source voltage vR, and a specified low dropout vDS = VQ. The VVdc updates instantly, through the control loop of the master LCR, which means that all slave MOSFETs have almost the same biases on their flat vGS-characteristic curves. This leads to all of the string LED currents being equal to each other, producing an almost even luminance. An experimental setup with microchip control is built to verify the estimations. Experimental results show that the luminance of all of the string LEDs are almost equal to one another, with a maximum deviation below 1% during a wide dimming range, while keeping all vDS of the MOSFETs at a low dropout voltage, as expected.

  7. Rethinking the dose-response relationship between usage and outcome in an online intervention for depression: randomized controlled trial.

    Science.gov (United States)

    Donkin, Liesje; Hickie, Ian B; Christensen, Helen; Naismith, Sharon L; Neal, Bruce; Cockayne, Nicole L; Glozier, Nick

    2013-10-17

    There is now substantial evidence that Web-based interventions can be effective at changing behavior and successfully treating psychological disorders. However, interest in the impact of usage on intervention outcomes has only been developed recently. To date, persistence with or completion of the intervention has been the most commonly reported metric of use, but this does not adequately describe user behavior online. Analysis of alternative measures of usage and their relationship to outcome may help to understand how much of the intervention users may need to obtain a clinically significant benefit from the program. The objective of this study was to determine which usage metrics, if any, are associated with outcome in an online depression treatment trial. Cardiovascular Risk E-couch Depression Outcome (CREDO) is a randomized controlled trial evaluating an unguided Web-based program (E-couch) based on cognitive behavioral therapy and interpersonal therapy for people with depression and cardiovascular disease. In all, 280 participants in the active arm of the trial commenced the program, delivered in 12 modules containing pages of text and activities. Usage data (eg, number of log-ins, modules completed, time spent online, and activities completed) were captured automatically by the program interface. We estimated the association of these and composite metrics with the outcome of a clinically significant improvement in depression score on the Patient Health Questionnaire (PHQ-9) of ≥ 5 points. In all, 214/280 (76.4%) participants provided outcome data at the end of the 12-week period and were included in the analysis. Of these, 94 (43.9%) participants obtained clinically significant improvement. Participants logged into the program an average of 18.7 times (SD 8.3) with most (62.1%, 133/214) completing all 12 modules. Average time spent online per log-in was 17.3 minutes (SD 10.5). Participants completed an average of 9 of 18 activities available within the

  8. A Unified Pricing of Variable Annuity Guarantees under the Optimal Stochastic Control Framework

    Directory of Open Access Journals (Sweden)

    Pavel V. Shevchenko

    2016-07-01

    Full Text Available In this paper, we review pricing of the variable annuity living and death guarantees offered to retail investors in many countries. Investors purchase these products to take advantage of market growth and protect savings. We present pricing of these products via an optimal stochastic control framework and review the existing numerical methods. We also discuss pricing under the complete/incomplete financial market models, stochastic mortality and optimal/sub-optimal policyholder behavior, and in the presence of taxes. For numerical valuation of these contracts in the case of simple risky asset process, we develop a direct integration method based on the Gauss-Hermite quadratures with a one-dimensional cubic spline for calculation of the expected contract value, and a bi-cubic spline interpolation for applying the jump conditions across the contract cashflow event times. This method is easier to implement and faster when compared to the partial differential equation methods if the transition density (or its moments of the risky asset underlying the contract is known in closed form between the event times. We present accurate numerical results for pricing of a Guaranteed Minimum Accumulation Benefit (GMAB guarantee available on the market that can serve as a numerical benchmark for practitioners and researchers developing pricing of variable annuity guarantees to assess the accuracy of their numerical implementation.

  9. Fine scale spatial variability of microbial pesticide degradation in soil: scales, controlling factors, and implications

    DEFF Research Database (Denmark)

    Dechesne, Arnaud; Badawi, N.; Aamand, Jens

    2014-01-01

    across pesticide classes: they include some soil characteristics (pH) and some agricultural management practices (pesticide application, tillage), while other potential controlling factors have more conflicting effects depending on the site or the pesticide. Evidence demonstrating the importance......Pesticide biodegradation is a soil microbial function of critical importance for modern agriculture and its environmental impact. While it was once assumed that this activity was homogeneously distributed at the field scale, mounting evidence indicates that this is rarely the case. Here, we...... critically examine the literature on spatial variability of pesticide biodegradation in agricultural soil. We discuss the motivations, methods, and main findings of the primary literature. We found significant diversity in the approaches used to describe and quantify spatial heterogeneity, which complicates...

  10. An empirical model for independent control of variable speed refrigeration system

    International Nuclear Information System (INIS)

    Li Hua; Jeong, Seok-Kwon; Yoon, Jung-In; You, Sam-Sang

    2008-01-01

    This paper deals with an empirical dynamic model for decoupling control of the variable speed refrigeration system (VSRS). To cope with inherent complexity and nonlinearity in system dynamics, the model parameters are first obtained based on experimental data. In the study, the dynamic characteristics of indoor temperature and superheat are assumed to be first-order model with time delay. While the compressor frequency and opening angle of electronic expansion valve are varying, the indoor temperature and the superheat exhibit interfering characteristics each other in the VSRS. Thus, each decoupling model has been proposed to eliminate such interference. Finally, the experiment and simulation results indicate that the proposed model offers more tractable means for describing the actual VSRS comparing to other models currently available

  11. Improving understanding of controls on spatial variability in methane fluxes in Arctic tundra

    Science.gov (United States)

    Davidson, Scott J.; Sloan, Victoria; Phoenix, Gareth; Wagner, Robert; Oechel, Walter; Zona, Donatella

    2015-04-01

    The Arctic is experiencing rapid climate change relative to the rest of the globe, and this increase in temperature has feedback effects across hydrological and thermal regimes, plant community distribution and carbon stocks within tundra soils. Arctic wetlands account for a significant amount of methane emissions from natural ecosystems to the atmosphere and with further permafrost degradation under a warming climate, these emissions are expected to increase. Methane (CH4) is an extremely important component of the global carbon cycle with a global warming potential 28.5 times greater than carbon dioxide over a 100 year time scale (IPCC, 2013). In order to validate carbon cycle models, modelling methane at broader landscape scales is needed. To date direct measurements of methane have been sporadic in time and space which, while capturing some key controls on the spatial heterogeneity, make it difficult to accurately upscale methane emissions to the landscape and regional scales. This study investigates what is controlling the spatial heterogeneity of methane fluxes across Arctic tundra. We combined over 300 portable chamber observations from 13 micro-topographic positions (with multiple vegetation types) across three locations spanning a 300km latitudinal gradient in Northern Alaska from Barrow to Ivotuk with synchronous measurements of environmental (soil temperature, soil moisture, water table, active layer thaw depth, pH) and vegetation (plant community composition, height, sedge tiller counts) variables to evaluate key controls on methane fluxes. To assess the diurnal variation in CH4 fluxes, we also performed automated chamber measurements in one study site (Barrow) location. Multiple statistical approaches (regression tree and multiple linear regression) were used to identify key controlling variables and their interactions. Methane emissions across all sites ranged from -0.08 to 15.3 mg C-CH4 m-2 hr-1. As expected, soil moisture was the main control

  12. Can anti-Mullerian hormone (AMH) predict the outcome of intrauterine insemination with controlled ovarian stimulation?

    Science.gov (United States)

    Bakas, Panagiotis; Boutas, Ioannis; Creatsa, Maria; Vlahos, Nicos; Gregoriou, Odysseas; Creatsas, George; Hassiakos, Dimitrios

    2015-10-01

    To assess whether the levels of anti-Mullerian hormone (AMH) are related to outcome of intrauterine insemination (IUI) in patients treated with gonadotropins. A total of 195 patients underwent controlled ovarian stimulation (COS) with recombinant follicle stimulating hormone (rFSH) (50-150 IU/d). All patients were submitted upto three cycles of IUI. Primary outcome was the ability of AMH levels to predict clinical pregnancy at first attempt and the cumulative clinical pregnancy probability of upto three IUI cycles. Secondary outcomes were the relation of AMH, LH, FSH, BMI, age, parity and basic estradiol levels with each other and the outcome of IUI. The area under the receiver operating characteristic (ROC) curve in predicting clinical pregnancy for AMH at first attempt was 0.53 and for cumulative clinical pregnancy was 0.76. AMH levels were positively correlated with clinical pregnancy rate at first attempt and with cumulative clinical pregnancy rate, but negatively correlated with patient's age and FSH levels. Patient's FSH, LH levels were negatively correlated with cumulative clinical pregnancy rate. AMH levels seem to have a positive correlation and patient's age and LH levels had a negative correlation with the outcome of IUI and COS with gonadotropins. AMH concentration was significantly higher and LH was significantly lower in patients with a clinical pregnancy after three cycles of IUI treatment compared with those who did not achieve pregnancy.

  13. Fine scale spatial variability of microbial pesticide degradation in soil: scales, controlling factors, and implications

    Directory of Open Access Journals (Sweden)

    Arnaud eDechesne

    2014-12-01

    Full Text Available Pesticide biodegradation is a soil microbial function of critical importance for modern agriculture and its environmental impact. While it was once assumed that this activity was homogeneously distributed at the field scale, mounting evidence indicates that this is rarely the case. Here, we critically examine the literature on spatial variability of pesticide biodegradation in agricultural soil. We discuss the motivations, methods, and main findings of the primary literature. We found significant diversity in the approaches used to describe and quantify spatial heterogeneity, which complicates inter-studies comparisons. However, it is clear that the presence and activity of pesticide degraders is often highly spatially variable with coefficients of variation often exceeding 50% and frequently displays nonrandom spatial patterns. A few controlling factors have tentatively been identified across pesticide classes: they include some soil characteristics (pH and some agricultural management practices (pesticide application, tillage, while other potential controlling factors have more conflicting effects depending on the site or the pesticide. Evidence demonstrating the importance of spatial heterogeneity on the fate of pesticides in soil has been difficult to obtain but modelling and experimental systems that do not include soil’s full complexity reveal that this heterogeneity must be considered to improve prediction of pesticide biodegradation rates or of leaching risks. Overall, studying the spatial heterogeneity of pesticide biodegradation is a relatively new field at the interface of agronomy, microbial ecology, and geosciences and a wealth of novel data is being collected from these different disciplinary perspectives. We make suggestions on possible avenues to take full advantage of these investigations for a better understanding and prediction of the fate of pesticides in soil.

  14. Host outdoor exposure variability affects the transmission and spread of Zika virus: Insights for epidemic control.

    Directory of Open Access Journals (Sweden)

    Marco Ajelli

    2017-09-01

    Full Text Available Zika virus transmission dynamics in urban environments follow a complex spatiotemporal pattern that appears unpredictable and barely related to high mosquito density areas. In this context, human activity patterns likely have a major role in Zika transmission dynamics. This paper examines the effect of host variability in the amount of time spent outdoors on Zika epidemiology in an urban environment.First, we performed a survey on time spent outdoors by residents of Miami-Dade County, Florida. Second, we analyzed both the survey and previously published national data on outdoors time in the U.S. to provide estimates of the distribution of the time spent outdoors. Third, we performed a computational modeling evaluation of Zika transmission dynamics, based on the time spent outdoors by each person. Our analysis reveals a strong heterogeneity of the host population in terms of time spent outdoors-data are well captured by skewed gamma distributions. Our model-based evaluation shows that in a heterogeneous population, Zika would cause a lower number of infections than in a more homogenous host population (up to 4-fold differences, but, at the same time, the epidemic would spread much faster. We estimated that in highly heterogeneous host populations the timing of the implementation of vector control measures is the major factor for limiting the number of Zika infections.Our findings highlight the need of considering host variability in exposure time for managing mosquito-borne infections and call for the revision of the triggers for vector control strategies, which should integrate mosquito density data and human outdoor activity patterns in specific areas.

  15. The Performance Test for Reactor Coolant Pump (RCP) adopting Variable Restriction Orifice Type Control Valve

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.; Bae, B. U.; Cho, Y. J. and others

    2014-05-15

    The design values of the RCPTF are 17.2 MPa, 343 .deg. C, 11.7 m{sup 3}/s, and 13 MW in the maximum pressure, temperature, flow rate, and electrical power, respectively. In the RCPTF, various types of tests can be performed including a hydraulic performance test to acquire a H-Q curve as well seal transient tests, thrust bearing transient test, cost down test, NPSHR verification test, and so on. After a commissioning startup test was successfully perfomed, mechanical structures are improved including a flow stabilizer and variable restriction orifice. Two- branch pipe (Y-branch) was installed to regulate the flow rate in the range of performance tests. In the main pipe, a flow restrictor (RO: Restriction Orifice) for limiting the maximum flow rate was installed. In the branch pipe line, a globe valve and a butterfly valves for regulating the flow rate was located on the each branch line. When the pressure loss of the valve side is smaller than that of the RO side, the flow rate of valve side was increasing and the flow disturbance was occurred in the lower pipe line. Due to flow disturbnace, it is to cause an error when measuring RCP head and flow measurement of the venturi flow meter installed in the lower main pipe line, and thus leading to a decrease in measurement accuracy as a result. To increase the efficiency of the flow control availability of the test facility, the variable restriction orifice (VRO) type flow control valve was designed and manufactured. In the RCPTF in KAERI, the performance tests and various kinds of transient tests of the RCP were successfully performed. In this study, H-Q curve of the pump using the VRO revealed a similar trend to the result from two ROs. The VRO was confirmed to effectively cover the full test range of the flow rate.

  16. Controls and variability of solute and sedimentary fluxes in Arctic and sub-Arctic Environments

    Science.gov (United States)

    Dixon, John

    2015-04-01

    Six major factors consistently emerge as controls on the spatial and temporal variability in sediment and solute fluxes in cold climates. They are climatic, geologic, physiographic or relief, biologic, hydrologic, and regolith factors. The impact of these factors on sediment and solute mass transfer in Arctic and sub-Arctic environments is examined. Comparison of non-glacierized Arctic vs. subarctic drainage basins reveals the effects of these controls. All drainage basins exhibit considerable variability in rates of sediment and solute fluxes. For the non-glacierized drainage basins there is a consistent increase in sediment mass transfer by slope processes and fluvial processes as relief increases. Similarly, a consistent increase in sediment mass transfer by slope and fluvial processes is observed as total precipitation increases. Similar patterns are also observed with respect to solute transport and relief and precipitation. Lithologic factors are most strongly observed in the contrast between volcanic vs. plutonic igneous bedrock substrates. Basins underlain by volcanic rocks display greater mass transfers than those underlain by plutonic rocks. Biologic influences are most strongly expressed by variations in extent of vegetation cover and the degree of human interference, with human impacted basins generating greater fluxes. For glacierized basins the fundamental difference to non-glacierized basins is an overall increase in mean annual mass transfers of sediment and a generally smaller magnitude solute transfer. The principal role of geology is observed with respect to lithology. Catchments underlain by limestone demonstrate substantially greater solute mass transfers than sediment transfer. The influence of relief is seen in the contrast in mass transfers between upland and lowland drainage basins with upland basins generating greater sediment and solute transfers than lowland basins. For glacierized basins the effects of biology and regolith appear to be

  17. The validity of the variable "NICU admission" as an outcome measure for neonatal morbidity: a retrospective study

    NARCIS (Netherlands)

    Wiegerinck, Melanie M. J.; Danhof, Nora A.; van Kaam, Anton H.; Tamminga, Pieter; Mol, Ben Willem J.

    2014-01-01

    To determine whether "neonatal intensive care unit (NICU) admission" is a valid surrogate outcome measure to assess neonatal condition in clinical studies. Retrospective study. Tertiary hospital in the Netherlands. Neonates admitted to NICU during a 10-year period. Inclusion was restricted to

  18. Psychological outcomes and health beliefs in adolescent and young adult survivors of childhood cancer and controls.

    Science.gov (United States)

    Kazak, Anne E; Derosa, Branlyn Werba; Schwartz, Lisa A; Hobbie, Wendy; Carlson, Claire; Ittenbach, Richard F; Mao, Jun J; Ginsberg, Jill P

    2010-04-20

    PURPOSE The purpose of this study was to compare adolescent and young adult (AYA) pediatric cancer survivors and peers without a history of serious illness on psychological distress, health-related quality of life (HRQOL), health beliefs; examine age at diagnosis and cancer treatment intensity on these outcomes; and examine relationships between number of health problems and the outcomes. PATIENTS AND METHODS AYA cancer survivors (n = 167) and controls (n = 170), recruited during visits to a cancer survivorship clinic and primary care, completed self-report questionnaires of distress, health problems, and health beliefs. For survivors, providers rated treatment intensity and health problems. Results There were no statistically significant differences between survivors and controls in psychological distress or HRQOL. Cancer survivors had less positive health beliefs. Survivors diagnosed as adolescents had significantly greater psychological distress and fewer positive health beliefs than those diagnosed earlier. Survivors with the highest level of treatment intensity had greater anxiety and fewer positive health beliefs than those with less intense treatments. Provider report of current health problems related to survivors' beliefs and mental HRQOL only, whereas patient report of health problems correlated significantly with most psychosocial outcomes and beliefs. CONCLUSION AYA cancer survivors did not differ from peers in psychological adjustment but did endorse less adaptive health beliefs. Survivors diagnosed during adolescence and who had more intensive cancer treatments evidenced poorer psychosocial outcomes. Beliefs about health may be identified and targeted for intervention to improve quality of life, particularly when patient perceptions of current health problems are considered.

  19. Control and Health Monitoring of Variable Speed Wind Power Generation Systems; Period of Performance: 10 July 1997 - 10 July 2000

    Energy Technology Data Exchange (ETDEWEB)

    Song, Y. D.; Bikdash, M.; Schulz, M. J.

    2001-09-01

    This document reports accomplishments on variable speed control, furling analysis, and health monitoring of wind turbines. There are three parts, prepared by Song, Bikdash, and Schulz, respectively. The first part discusses variable-speed control of wind turbines, exploring a memory-based method for wind speed prediction and wind turbine control. The second part addresses the yaw dynamics of wind turbines, including modeling, analysis, and control. The third part of the report discusses new analytical techniques that were developed and tested to detect initial damage to prevent failures of wind turbine rotor blades.

  20. Risks and Outcomes Associated with Disorganized/Controlling Patterns of Attachment at Age Three in the NICHD Study of Early Child Care and Youth Development.

    Science.gov (United States)

    O'Connor, Erin; Bureau, Jean-Francois; McCartney, Kathleen; Lyons-Ruth, Karlen

    2011-07-01

    Disorganized/controlling attachment in preschool has been found to be associated with maternal and child maladjustment, making it of keen interest in the study of psychopathology. Additional work is needed, however, to better understand disorganized/controlling attachment occurring as early as age three. The primary aims of this study were to evaluate risk factors and outcomes associated with disorganized/controlling behavior at age three and to evaluate the risk factors and outcomes differentiating the four subtypes of disorganized/controlling attachment. Analyses were conducted with the first two phases of the NICHD Study of Early Child Care and Youth Development, a prospective study of 1,364 children from birth. At 36 months of age, across the attachment-relevant domains of maternal well-being, mother-child interactions, and child social adaptation, the disorganized/controlling group evidenced the most maladaptive patterns in comparison to both secure and insecure-organized groups. At 54 months of age, the disorganized/controlling group displayed the highest levels of internalizing and externalizing behavior problems, as rated by mothers and teachers, and the lowest quality relationships with teachers. Significant differences found among the disorganized/controlling subtypes indicated that the behaviorally disorganized and controlling-punitive subtypes had more maladaptive patterns across variables than did the controlling-caregiving and controlling-mixed subtypes.

  1. Visual outcome, endocrine function and tumor control after fractionated stereotactic radiation therapy of craniopharyngiomas in adults

    DEFF Research Database (Denmark)

    Astradsson, Arnar; Munck Af Rosenschöld, Per; Feldt-Rasmussen, Ulla

    2017-01-01

    BACKGROUND: The purpose of this study was to examine visual outcome, endocrine function and tumor control in a prospective cohort of craniopharyngioma patients, treated with fractionated stereotactic radiation therapy (FSRT). MATERIAL AND METHODS: Sixteen adult patients with craniopharyngiomas were...... eligible for analysis. They were treated with linear accelerator-based FSRT during 1999-2015. In all cases, diagnosis was confirmed by histological analysis. The prescription dose to the tumor was 54 Gy (median, range 48-54) in 1.8 or 2.0 Gy per fraction, and the maximum radiation dose to the optic nerves.......7-13.1) for visual outcome, endocrine function, and tumor control, respectively. RESULTS: Visual acuity impairment was present in 10 patients (62.5%) and visual field defects were present in 12 patients (75%) before FSRT. One patient developed radiation-induced optic neuropathy at seven years after FSRT. Thirteen...

  2. Loss of control eating and weight outcomes after bariatric surgery: a study with a Portuguese sample

    OpenAIRE

    Conceição, Eva Martins; Silva, Ana Isabel Pinto Bastos Leite; Brandão, Isabel; Vaz, Ana Rita Rendeiro Ribeiro; Ramalho, Sofia Marlene Marques; Arrojado, Filipa; Costa, José; Machado, Paulo P. P.

    2014-01-01

    The present study aim is to investigate the frequency of loss of control eating (LOC) episodes in three groups with different assessment times: one before, one at short and one at long-term after bariatric surgery; as well as to explore the association of postoperative problematic eating behaviors and weight outcomes and psychological characteristics. This cross-sectional study compared a group of preoperative bariatric surgery patients (n = 176) and two postoperative groups, one at short-ter...

  3. Design of a Polynomial Fuzzy Observer Controller With Sampled-Output Measurements for Nonlinear Systems Considering Unmeasurable Premise Variables

    OpenAIRE

    Liu, Chuang; Lam, H. K.

    2015-01-01

    In this paper, we propose a polynomial fuzzy observer controller for nonlinear systems, where the design is achieved through the stability analysis of polynomial-fuzzy-model-based (PFMB) observer-control system. The polynomial fuzzy observer estimates the system states using estimated premise variables. The estimated states are then employed by the polynomial fuzzy controller for the feedback control of nonlinear systems represented by the polynomial fuzzy model. The system stability of the P...

  4. Thyroid peroxidase antibodies in pregnant women with type 1 diabetes: impact on thyroid function, metabolic control and pregnancy outcome

    DEFF Research Database (Denmark)

    Vestgaard, Marianne; Nielsen, Lene Ringholm; Rasmussen, Åse Krogh

    2008-01-01

    In pregnant women with type 1 diabetes, we evaluated whether the presence of thyroid peroxidase autoantibodies (anti-TPO) was associated with changes in thyroid function, metabolic control and pregnancy outcome.......In pregnant women with type 1 diabetes, we evaluated whether the presence of thyroid peroxidase autoantibodies (anti-TPO) was associated with changes in thyroid function, metabolic control and pregnancy outcome....

  5. Social outcomes of young adults with childhood-onset epilepsy: A case-sibling-control study.

    Science.gov (United States)

    Baca, Christine B; Barry, Frances; Vickrey, Barbara G; Caplan, Rochelle; Berg, Anne T

    2017-05-01

    We aimed to compare long-term social outcomes in young adults with childhood-onset epilepsy (cases) with neurologically normal sibling controls. Long-term social outcomes were assessed at the 15-year follow-up of the Connecticut Study of Epilepsy, a community-based prospective cohort study of children with newly diagnosed epilepsy. Young adults with childhood-onset epilepsy with complicated (abnormal neurologic exam findings, abnormal brain imaging with lesion referable to epilepsy, intellectual disability (ID; IQ < 60) or informative history of neurologic insults to which the occurrence of epilepsy might be attributed), and uncomplicated epilepsy presentations were compared to healthy sibling controls. Age, gender, and matched-pair adjusted generalized linear models stratified by complicated epilepsy and 5-year seizure-free status estimated adjusted odds ratios (aORs) and 95% confidence intervals [CIs] for each outcome. The 15-year follow-up included 361 individuals with epilepsy (59% of initial cases; N = 291 uncomplicated and N = 70 complicated epilepsy; mean age 22 years [standard deviation, SD 3.5]; mean epilepsy onset 6.2 years [SD 3.9]) and 173 controls. Social outcomes for cases with uncomplicated epilepsy with ≥5 years terminal remission were comparable to controls; cases with uncomplicated epilepsy <5 years seizure-free were more likely to be less productive (school/employment < 20 h/week) (aOR 3.63, 95% CI 1.83-7.20) and not to have a driver's license (aOR 6.25, 95% CI 2.85-13.72). Complicated cases with epilepsy <5 years seizure-free had worse outcomes across multiple domains; including not graduating high school (aOR 24.97, 95% CI 7.49-83.30), being un- or underemployed (<20 h/week) (aOR 11.06, 95% CI 4.44-27.57), being less productively engaged (aOR 15.71, 95% CI 6.88-35.88), and not living independently (aOR 10.24, 95% CI 3.98-26.36). Complicated cases without ID (N = 36) had worse outcomes with respect to productive engagement (aOR 6.02; 95% CI 2

  6. Women's perceived internal control of future pregnancy outcomes and its related factors.

    Science.gov (United States)

    Maleki, Azam; Mazloomzadeh, Saeideh

    2013-03-01

    With regards to the importance of women's beliefs in improving pregnancy outcomes, this study was performed to determine the perceived internal control on future pregnancy outcomes and its related factors in women who participated in pre-marital counseling. In a cross-sectional study, women's perceived internal control was investigated. The study population comprised the women in reproductive age of whom 400 were selected by random sampling. Data collection instrument was a questionnaire consisting of demographic, pre-conceptional care, and internal control questions. Two categories of favorite and not favorite levels of internal control were defined based on the total score. The validity of the questionnaire was determined via content validity method by use of experts' opinion and its reliability was evaluated through the calculation of Cronbach's alpha coefficient which was 0.76. Data were analyzed through frequency tables, correlation coefficient, and Chi-square test at the confidence level of 0.95. Two hundred sixty-five (65%) women had a good perceived internal control and it was significantly associated with the age, educational level, and hearing about pre-conceptional care. The internal control score also showed a positive and significant correlation with both age and the subject knowledge about folic acid (r = 0.19 and r = 0.15, respectively). The majority of women had a favorite perceived internal control. Since age and educational level were the affecting factors on the perceived internal control of women, promoting the level of internal control in young women and those with low education in pre-marital counseling classes seems necessary.

  7. First and higher order, heuristically based generalized perturbation theory (HGPT) with optional control reset variable

    International Nuclear Information System (INIS)

    Gandini, A.

    1996-01-01

    The heuristically based generalized perturbation theory (HGPT), to first and higher order, applied to the neutron field of a reactor system, is discussed in relation to the criticality reset procedure. This procedure is implicit within the GPT methodology, corresponding to the so called filtering of the importance function relevant to the neutron field from the fundamental mode contamination. It is common practice to use the so called ''lambda''-mode filter. In order to account for any possible reset option, a general definition is introduced of an intensive control variable (ρ) entering into the governing equations, and correspondingly a fundamental ρ-mode filtering of the importance function is defined, relevant to the real criticality reset (control) mechanism adopted. A simple example illustrates the need to take into account the correct filtering, so as to avoid significant inaccuracies in the sensitivity calculation results. The extension of this filtering technique to other functions entering into the GPT perturbative formulations at first and higher order is also discussed. (author)

  8. Can adverse maternal and perinatal outcomes be predicted when blood pressure becomes elevated? Secondary analyses from the CHIPS (Control of Hypertension In Pregnancy Study) randomized controlled trial.

    Science.gov (United States)

    Magee, Laura A; von Dadelszen, Peter; Singer, Joel; Lee, Terry; Rey, Evelyne; Ross, Susan; Asztalos, Elizabeth; Murphy, Kellie E; Menzies, Jennifer; Sanchez, Johanna; Gafni, Amiram; Gruslin, Andrée; Helewa, Michael; Hutton, Eileen; Lee, Shoo K; Logan, Alexander G; Ganzevoort, Wessel; Welch, Ross; Thornton, Jim G; Moutquin, Jean Marie

    2016-07-01

    For women with chronic or gestational hypertension in CHIPS (Control of Hypertension In Pregnancy Study, NCT01192412), we aimed to examine whether clinical predictors collected at randomization could predict adverse outcomes. This was a planned, secondary analysis of data from the 987 women in the CHIPS Trial. Logistic regression was used to examine the impact of 19 candidate predictors on the probability of adverse perinatal (pregnancy loss or high level neonatal care for >48 h, or birthweight hypertension, preeclampsia, or delivery at blood pressure within 1 week before randomization. Continuous variables were represented continuously or dichotomized based on the smaller p-value in univariate analyses. An area-under-the-receiver-operating-curve (AUC ROC) of ≥0.70 was taken to reflect a potentially useful model. Point estimates for AUC ROC were hypertension (0.70, 95% CI 0.67-0.74) and delivery at hypertension develop an elevated blood pressure in pregnancy, or formerly normotensive women develop new gestational hypertension, maternal and current pregnancy clinical characteristics cannot predict adverse outcomes in the index pregnancy. © 2016 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).

  9. Fetal MR imaging of posterior intracranial dural sinus thrombosis: a report of three cases with variable outcomes

    International Nuclear Information System (INIS)

    Byrd, Sharon E.; Elias, Dean; Abramowicz, Jacques S.; Kent, Paul; Kimura, Robert E.; Heydeman, Peter T.

    2012-01-01

    Thrombosis of fetal intracranial dural sinuses is a rare entity. A specific type of midline dural sinus thrombosis (DST) at the torcular Herophili with extension into the superior sagittal sinus (SSS) was initially seen on fetal US and was referred to fetal MRI for definite diagnosis and better delineation. Retrospective comparison to medical literature of three cases, diagnosed at our institution, of midline fetal DST with MR imaging findings and clinical outcomes. We reviewed MRI findings on T2-weighted images of our three cases of fetal midline DST and clinical outcomes of these fetuses and compared our findings to medical literature. The MR imaging and clinical findings of our cases extend over 6 years. They consist of three pregnant women, 31-39 years of age each with a single fetus, with fetal MR imaging performed at different gestational ages (GA). Case 1 the MR imaging was performed at 21 5/7 weeks' GA, case 2 at 24 and 33 4/7 weeks' GA, and case 3 at 22 and 25 weeks' GA. Postnatal MRI was performed in case 2 at 6 months of life and case 3 at 1 day of life. Clinical follow-up occurred during the last 6 years. In all of our cases, T2-W MR imaging demonstrated ballooned midline torcular Herophili with iso- to hypointense mass with or without focal eccentric area of greater hypointensity occupying the torcular Herophili with extension into the SSS. Case 3 had associated leptomeningeal dural vascular malformation overlying the left cerebral hemisphere with development of migrational disorder in the left cerebral hemisphere. Clinical outcome consisted of fetal demise in case 1, normal postnatal outcome in case 2 and severe brain damage with poor postnatal outcome in case 3. Our findings of large iso-hypointense thrombus with or without a focal eccentric area more hypointense to thrombus in a dilated torcular Herophili with extension into the SSS on T2-W images corresponds to the majority of cases of this rare type of DST in the medical literature. (orig.)

  10. Fetal MR imaging of posterior intracranial dural sinus thrombosis: a report of three cases with variable outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Byrd, Sharon E.; Elias, Dean [Rush Medical College and Rush University Medical Center, Department of Diagnostic Radiology and Nuclear Medicine Section of Neuroradiology, Chicago, IL (United States); Abramowicz, Jacques S. [Rush Medical College and Rush University Medical Center, Department of Obstetrics and Gynecology, Rush Fetal and Neonatal Medicine Center, Chicago, IL (United States); Kent, Paul [Rush Medical College and Rush University Medical Center, Department of Pediatrics, Division of Hematology and Oncology, Chicago, IL (United States); Kimura, Robert E. [Rush Medical College and Rush University Medical Center, Department of Pediatrics, Division of Neonatology, Chicago, IL (United States); Heydeman, Peter T. [Rush Medical College and Rush University Medical Center, Department of Pediatrics, Division of Pediatric Neurology, Chicago, IL (United States)

    2012-05-15

    Thrombosis of fetal intracranial dural sinuses is a rare entity. A specific type of midline dural sinus thrombosis (DST) at the torcular Herophili with extension into the superior sagittal sinus (SSS) was initially seen on fetal US and was referred to fetal MRI for definite diagnosis and better delineation. Retrospective comparison to medical literature of three cases, diagnosed at our institution, of midline fetal DST with MR imaging findings and clinical outcomes. We reviewed MRI findings on T2-weighted images of our three cases of fetal midline DST and clinical outcomes of these fetuses and compared our findings to medical literature. The MR imaging and clinical findings of our cases extend over 6 years. They consist of three pregnant women, 31-39 years of age each with a single fetus, with fetal MR imaging performed at different gestational ages (GA). Case 1 the MR imaging was performed at 21 5/7 weeks' GA, case 2 at 24 and 33 4/7 weeks' GA, and case 3 at 22 and 25 weeks' GA. Postnatal MRI was performed in case 2 at 6 months of life and case 3 at 1 day of life. Clinical follow-up occurred during the last 6 years. In all of our cases, T2-W MR imaging demonstrated ballooned midline torcular Herophili with iso- to hypointense mass with or without focal eccentric area of greater hypointensity occupying the torcular Herophili with extension into the SSS. Case 3 had associated leptomeningeal dural vascular malformation overlying the left cerebral hemisphere with development of migrational disorder in the left cerebral hemisphere. Clinical outcome consisted of fetal demise in case 1, normal postnatal outcome in case 2 and severe brain damage with poor postnatal outcome in case 3. Our findings of large iso-hypointense thrombus with or without a focal eccentric area more hypointense to thrombus in a dilated torcular Herophili with extension into the SSS on T2-W images corresponds to the majority of cases of this rare type of DST in the medical literature

  11. Second-order Sliding Mode Control of DFIG Based Variable Speed Wind Turbine for Maximum Power Point Tracking

    Institute of Scientific and Technical Information of China (English)

    Xiangjie Liu; Chengcheng Wang; Yaozhen Han

    2017-01-01

    This paper proposes a super-twisting second order sliding mode control scheme to maximize the wind energy capture of a doubly fed induction generator based variable speed wind turbine (VSWT) system, and minimize the reactive power simultaneously. Two second order sliding mode controllers are designed to achieve the control objectives, reduce mechanical stress and improve control accuracy. By regulating the generator rotor voltage, one controller makes the wind turbine rotor speed track the optimal speed, which can maximize power generation. The other maintains the rotor current at rated value to minimize the reactive power. A quadratic form Lyapunov function is adopted to determine the range of controller parameters and guarantee the finite time stability. Simulation results on a 1.5 MW doubly fed induction generator (DFIG)-based variable speed wind turbine demonstrate the validity of the proposed control strategy.

  12. Algal bloom sedimentation induces variable control of lake eutrophication by phosphorus inactivating agents

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Changhui [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Bai, Leilei [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate University of Chinese Academy of Sciences (China); Jiang, He-Long, E-mail: hljiang@niglas.ac.cn [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Xu, Huacheng [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China)

    2016-07-01

    Lake eutrophication typically occurs with a syndrome of algae breeding and biomass accumulation (e.g., algal blooms). Therefore, the effect of algal bloom sedimentation on eutrophication control by phosphorus (P) inactivating agents was assessed herein. Three commercial products, including aluminum (Al) sulfate, iron (Fe) sulfate, and a lanthanum-modified clay (Phoslock®), as well as one easily available by-product, drinking water treatment residue (DWTR), were selected. The most important finding was that during algae sedimentation, P immobilization from the overlying water by Al, Phoslock®, and DWTR was dominated by a long-term slow phase (> 150 d), while Fe has limited effectiveness on the immobilization. Further analysis indicated that the algae sedimentation effect was mainly due to the slow release of P from algae, leading to relatively limited P available for the inactivating agents. Then, a more unfavorable effect on the P immobilization capability of inactivating agents was caused by the induced anaerobic conditions, the released organic matter from algae, and the increased sulfide in the overlying water and sediments during sedimentation. Overall, algae sedimentation induced variable control of eutrophication by P inactivating agents. Accordingly, recommendations for future works about algal lake restoration were also proposed. - Highlights: • A long-term P immobilization by Phoslock®, DWTR, and Al was observed. • Fe had limited effectiveness on P pollution control for overlying water. • Al and Fe enhanced sulfur reduction, while DWTR and Phoslock® had minor effect. • The sedimentation reduced Al and La release from agents, but enhanced Fe release. • The agents changed organic matter compositions and structures in water columns.

  13. Algal bloom sedimentation induces variable control of lake eutrophication by phosphorus inactivating agents

    International Nuclear Information System (INIS)

    Wang, Changhui; Bai, Leilei; Jiang, He-Long; Xu, Huacheng

    2016-01-01

    Lake eutrophication typically occurs with a syndrome of algae breeding and biomass accumulation (e.g., algal blooms). Therefore, the effect of algal bloom sedimentation on eutrophication control by phosphorus (P) inactivating agents was assessed herein. Three commercial products, including aluminum (Al) sulfate, iron (Fe) sulfate, and a lanthanum-modified clay (Phoslock®), as well as one easily available by-product, drinking water treatment residue (DWTR), were selected. The most important finding was that during algae sedimentation, P immobilization from the overlying water by Al, Phoslock®, and DWTR was dominated by a long-term slow phase (> 150 d), while Fe has limited effectiveness on the immobilization. Further analysis indicated that the algae sedimentation effect was mainly due to the slow release of P from algae, leading to relatively limited P available for the inactivating agents. Then, a more unfavorable effect on the P immobilization capability of inactivating agents was caused by the induced anaerobic conditions, the released organic matter from algae, and the increased sulfide in the overlying water and sediments during sedimentation. Overall, algae sedimentation induced variable control of eutrophication by P inactivating agents. Accordingly, recommendations for future works about algal lake restoration were also proposed. - Highlights: • A long-term P immobilization by Phoslock®, DWTR, and Al was observed. • Fe had limited effectiveness on P pollution control for overlying water. • Al and Fe enhanced sulfur reduction, while DWTR and Phoslock® had minor effect. • The sedimentation reduced Al and La release from agents, but enhanced Fe release. • The agents changed organic matter compositions and structures in water columns.

  14. Heart Rate Variability Biofeedback Does Not Substitute for Asthma Steroid Controller Medication.

    Science.gov (United States)

    Lehrer, Paul M; Irvin, Charles G; Lu, Shou-En; Scardella, Anthony; Roehmheld-Hamm, Beatrix; Aviles-Velez, Milisyaris; Graves, Jessica; Vaschillo, Evgeny G; Vaschillo, Bronya; Hoyte, Flavia; Nelson, Harold; Wamboldt, Frederick S

    2018-03-01

    Despite previous findings of therapeutic effects for heart rate variability biofeedback (HRVB) on asthma, it is not known whether HRVB can substitute either for controller or rescue medication, or whether it affects airway inflammation. Sixty-eight paid volunteer steroid naïve study participants with mild or moderate asthma were given 3 months of HRVB or a comparison condition consisting of EEG alpha biofeedback with relaxing music and relaxed paced breathing (EEG+), in a two-center trial. All participants received a month of intensive asthma education prior to randomization. Both treatment conditions produced similar significant improvements on the methacholine challenge test (MCT), asthma symptoms, and asthma quality of life (AQOL). MCT effects were of similar size to those of enhanced placebo procedures reported elsewhere, and were 65% of those of a course of a high-potency inhaled steroid budesonide given to a sub-group of participants following biofeedback training. Exhaled nitric oxide decreased significantly only in the HRVB group, 81% of the budesonide effect, but with no significant differences between groups. Participants reported becoming more relaxed during practice of both techniques. Administration of albuterol after biofeedback sessions produced a large improvement in pulmonary function test results, indicating that neither treatment normalized pulmonary function as a potent controller medication would have done. Impulse oscillometry showed increased upper airway (vocal cord) resistance during biofeedback periods in both groups. These data suggest that HRVB should not be considered an alternative to asthma controller medications (e.g., inhaled steroids), although both biofeedback conditions produced some beneficial effects, warranting further research, and suggesting potential complementary effects. Various hypotheses are presented to explain why HRVB effects on asthma appeared smaller in this study than in earlier studies. Clinical Trial

  15. Statistical Learning and Adaptive Decision-Making Underlie Human Response Time Variability in Inhibitory Control

    Directory of Open Access Journals (Sweden)

    Ning eMa

    2015-08-01

    Full Text Available Response time (RT is an oft-reported behavioral measure in psychological and neurocognitive experiments, but the high level of observed trial-to-trial variability in this measure has often limited its usefulness. Here, we combine computational modeling and psychophysics to examine the hypothesis that fluctuations in this noisy measure reflect dynamic computations in human statistical learning and corresponding cognitive adjustments. We present data from the stop-signal task, in which subjects respond to a go stimulus on each trial, unless instructed not to by a subsequent, infrequently presented stop signal. We model across-trial learning of stop signal frequency, P(stop, and stop-signal onset time, SSD (stop-signal delay, with a Bayesian hidden Markov model, and within-trial decision-making with an optimal stochastic control model. The combined model predicts that RT should increase with both expected P(stop and SSD. The human behavioral data (n=20 bear out this prediction, showing P(stop and SSD both to be significant, independent predictors of RT, with P(stop being a more prominent predictor in 75% of the subjects, and SSD being more prominent in the remaining 25%. The results demonstrate that humans indeed readily internalize environmental statistics and adjust their cognitive/behavioral strategy accordingly, and that subtle patterns in RT variability can serve as a valuable tool for validating models of statistical learning and decision-making. More broadly, the modeling tools presented in this work can be generalized to a large body of behavioral paradigms, in order to extract insights about cognitive and neural processing from apparently quite noisy behavioral measures. We also discuss how this behaviorally validated model can then be used to conduct model-based analysis of neural data, in order to help identify specific brain areas for representing and encoding key computational quantities in learning and decision-making.

  16. Variable versus conventional lung protective mechanical ventilation during open abdominal surgery (PROVAR): a randomised controlled trial.

    Science.gov (United States)

    Spieth, P M; Güldner, A; Uhlig, C; Bluth, T; Kiss, T; Conrad, C; Bischlager, K; Braune, A; Huhle, R; Insorsi, A; Tarantino, F; Ball, L; Schultz, M J; Abolmaali, N; Koch, T; Pelosi, P; Gama de Abreu, M

    2018-03-01

    Experimental studies showed that controlled variable ventilation (CVV) yielded better pulmonary function compared to non-variable ventilation (CNV) in injured lungs. We hypothesized that CVV improves intraoperative and postoperative respiratory function in patients undergoing open abdominal surgery. Fifty patients planned for open abdominal surgery lasting >3 h were randomly assigned to receive either CVV or CNV. Mean tidal volumes and PEEP were set at 8 ml kg -1 (predicted body weight) and 5 cm H 2 O, respectively. In CVV, tidal volumes varied randomly, following a normal distribution, on a breath-by-breath basis. The primary endpoint was the forced vital capacity (FVC) on postoperative Day 1. Secondary endpoints were oxygenation, non-aerated lung volume, distribution of ventilation, and pulmonary and extrapulmonary complications until postoperative Day 5. FVC did not differ significantly between CVV and CNV on postoperative Day 1, 61.5 (standard deviation 22.1) % vs 61.9 (23.6) %, respectively; mean [95% confidence interval (CI)] difference, -0.4 (-13.2-14.0), P=0.95. Intraoperatively, CVV did not result in improved respiratory function, haemodynamics, or redistribution of ventilation compared to CNV. Postoperatively, FVC, forced expiratory volume at the first second (FEV 1 ), and FEV 1 /FVC deteriorated, while atelectasis volume and plasma levels of interleukin-6 and interleukin-8 increased, but values did not differ between groups. The incidence of postoperative pulmonary and extrapulmonary complications was comparable in CVV and CNV. In patients undergoing open abdominal surgery, CVV did not improve intraoperative and postoperative respiratory function compared with CNV. NCT 01683578. Copyright © 2017 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.

  17. Statistical learning and adaptive decision-making underlie human response time variability in inhibitory control.

    Science.gov (United States)

    Ma, Ning; Yu, Angela J

    2015-01-01

    Response time (RT) is an oft-reported behavioral measure in psychological and neurocognitive experiments, but the high level of observed trial-to-trial variability in this measure has often limited its usefulness. Here, we combine computational modeling and psychophysics to examine the hypothesis that fluctuations in this noisy measure reflect dynamic computations in human statistical learning and corresponding cognitive adjustments. We present data from the stop-signal task (SST), in which subjects respond to a go stimulus on each trial, unless instructed not to by a subsequent, infrequently presented stop signal. We model across-trial learning of stop signal frequency, P(stop), and stop-signal onset time, SSD (stop-signal delay), with a Bayesian hidden Markov model, and within-trial decision-making with an optimal stochastic control model. The combined model predicts that RT should increase with both expected P(stop) and SSD. The human behavioral data (n = 20) bear out this prediction, showing P(stop) and SSD both to be significant, independent predictors of RT, with P(stop) being a more prominent predictor in 75% of the subjects, and SSD being more prominent in the remaining 25%. The results demonstrate that humans indeed readily internalize environmental statistics and adjust their cognitive/behavioral strategy accordingly, and that subtle patterns in RT variability can serve as a valuable tool for validating models of statistical learning and decision-making. More broadly, the modeling tools presented in this work can be generalized to a large body of behavioral paradigms, in order to extract insights about cognitive and neural processing from apparently quite noisy behavioral measures. We also discuss how this behaviorally validated model can then be used to conduct model-based analysis of neural data, in order to help identify specific brain areas for representing and encoding key computational quantities in learning and decision-making.

  18. A protocol for a pragmatic randomized controlled trial evaluating outcomes of emergency nurse practitioner service.

    Science.gov (United States)

    Jennings, Natasha; Gardner, Glenn; O'Reilly, Gerard

    2014-09-01

    To evaluate emergency nurse practitioner service effectiveness on outcomes related to quality of care and service responsiveness. Increasing service pressures in the emergency setting have resulted in the adoption of service innovation models; the most common and rapidly expanding of these is the emergency nurse practitioner. The delivery of high quality patient care in the emergency department is one of the most important service indicators to be measured in health services today. The rapid uptake of emergency nurse practitioner service in Australia has outpaced the capacity to evaluate this model in outcomes related to safety and quality of patient care. Pragmatic randomized controlled trial at one site with 260 participants. This protocol describes a definitive prospective randomized controlled trial, which will examine the impact of emergency nurse practitioner service on key patient care and service indicators. The study control will be standard emergency department care. The intervention will be emergency nurse practitioner service. The primary outcome measure is pain score reduction and time to analgesia. Secondary outcome measures are waiting time, number of patients who did not wait, length of stay in the emergency department and representations within 48 hours. Scant research enquiry evaluating emergency nurse practitioner service on patient effectiveness and service responsiveness exists currently. This study is a unique trial that will test the effectiveness of the emergency nurse practitioner service on patients who present to the emergency department with pain. The research will provide an opportunity to further evaluate emergency nurse practitioner models of care and build research capacity into the workforce. Trial registration details: Australian and New Zealand Clinical Trials Registry dated 18th August 2013, ACTRN12613000933752. © 2014 John Wiley & Sons Ltd.

  19. Feasibility and early outcomes of laparoscopic plicated sleeve gastrectomy: a case-control study

    Directory of Open Access Journals (Sweden)

    Tomasz Rogula

    2016-01-01

    Full Text Available Introduction : Sleeve gastrectomy (SG continues to gain popularity as a viable weight loss procedure with well-documented outcomes and procedure-specific adverse effects. It has become increasingly indicated for the treatment of morbid obesity. Aim of the research : To compare a novel approach to SG, which aims to reduce SG-specific complications, to the standard SG procedure. Material and methods : Sixteen morbidly obese patients with a mean body mass index (BMI of 48.5 kg/m 2 ± SD who underwent the novel laparoscopic plicated sleeve gastrectomy (LPSG were retrospectively studied. The control group included 18 patients who underwent laparoscopic SG. Study and control groups were matched for BMI and gender. Study group patients underwent a partial SG with imbrication of the distal 2/3 of the staple line with 2 cm overlap and 3–4 cm of the pre-pyloric stomach. Control group SG patients had their staple line oversewn without plication. Outcomes at 3, 6 and 12 months were compared and analyzed. Results: There was no statistically significant difference in weight loss at 12 months between the LPSG and SG groups. Postoperative nausea was comparable between the two groups. No major complications were noted in either group. Conclusions: The LPSG is a modification of the standard SG which has comparable outcomes, safety and feasibility. It may lead to a decrease in unwanted complications such as sleeve stricture or obstruction. Further studies on long-term outcomes are needed to assess its value as a bariatric procedure.

  20. Habits as action sequences: hierarchical action control and changes in outcome value.

    Science.gov (United States)

    Dezfouli, Amir; Lingawi, Nura W; Balleine, Bernard W

    2014-11-05

    Goal-directed action involves making high-level choices that are implemented using previously acquired action sequences to attain desired goals. Such a hierarchical schema is necessary for goal-directed actions to be scalable to real-life situations, but results in decision-making that is less flexible than when action sequences are unfolded and the decision-maker deliberates step-by-step over the outcome of each individual action. In particular, from this perspective, the offline revaluation of any outcomes that fall within action sequence boundaries will be invisible to the high-level planner resulting in decisions that are insensitive to such changes. Here, within the context of a two-stage decision-making task, we demonstrate that this property can explain the emergence of habits. Next, we show how this hierarchical account explains the insensitivity of over-trained actions to changes in outcome value. Finally, we provide new data that show that, under extended extinction conditions, habitual behaviour can revert to goal-directed control, presumably as a consequence of decomposing action sequences into single actions. This hierarchical view suggests that the development of action sequences and the insensitivity of actions to changes in outcome value are essentially two sides of the same coin, explaining why these two aspects of automatic behaviour involve a shared neural structure. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  1. A balance of activity in brain control and reward systems predicts self-regulatory outcomes.

    Science.gov (United States)

    Lopez, Richard B; Chen, Pin-Hao A; Huckins, Jeremy F; Hofmann, Wilhelm; Kelley, William M; Heatherton, Todd F

    2017-05-01

    Previous neuroimaging work has shown that increased reward-related activity following exposure to food cues is predictive of self-control failure. The balance model suggests that self-regulation failures result from an imbalance in reward and executive control mechanisms. However, an open question is whether the relative balance of activity in brain systems associated with executive control (vs reward) supports self-regulatory outcomes when people encounter tempting cues in daily life. Sixty-nine chronic dieters, a population known for frequent lapses in self-control, completed a food cue-reactivity task during an fMRI scanning session, followed by a weeklong sampling of daily eating behaviors via ecological momentary assessment. We related participants' food cue activity in brain systems associated with executive control and reward to real-world eating patterns. Specifically, a balance score representing the amount of activity in brain regions associated with self-regulatory control, relative to automatic reward-related activity, predicted dieters' control over their eating behavior during the following week. This balance measure may reflect individual self-control capacity and be useful for examining self-regulation success in other domains and populations. © The Author (2017). Published by Oxford University Press.

  2. Language and speech outcomes of children with hearing loss and additional disabilities: Identifying the variables that influence performance at 5 years of age

    Science.gov (United States)

    Cupples, Linda; Ching, Teresa Y.C.; Button, Laura; Leigh, Greg; Marnane, Vivienne; Whitfield, Jessica; Gunnourie, Miriam; Martin, Louise

    2016-01-01

    Objective This study examined language and speech outcomes in young children with hearing loss and additional disabilities. Design Receptive and expressive language skills and speech output accuracy were evaluated using direct assessment and caregiver report. Results were analysed first for the entire participant cohort, and then to compare results for children with hearing aids (HAs) versus cochlear implants (CIs). Study sample A population-based cohort of 146 5-year-old children with hearing loss and additional disabilities took part. Results Across all participants, multiple regressions showed that better language outcomes were associated with milder hearing loss, use of oral communication, higher levels of cognitive ability and maternal education, and earlier device fitting. Speech output accuracy was associated with use of oral communication only. Average outcomes were similar for children with HAs versus CIs, but their associations with demographic variables differed. For HA users, results resembled those for the whole cohort. For CI users, only use of oral communication and higher cognitive ability levels were significantly associated with better language outcomes. Conclusions The results underscore the importance of early device fitting for children with additional disabilities. Strong conclusions cannot be drawn for CI users given the small number of participants with complete data. PMID:27630013

  3. Do motor control genes contribute to interindividual variability in decreased movement in patients with pain?

    Directory of Open Access Journals (Sweden)

    Mishra Bikash K

    2007-07-01

    Full Text Available Abstract Background Because excessive reduction in activities after back injury may impair recovery, it is important to understand and address the factors contributing to the variability in motor responses to pain. The current dominant theory is the "fear-avoidance model", in which the some patients' heightened fears of further injury cause them to avoid movement. We propose that in addition to psychological factors, neurochemical variants in the circuits controlling movement and their modification by pain may contribute to this variability. A systematic search of the motor research literature and genetic databases yielded a prioritized list of polymorphic motor control candidate genes. We demonstrate an analytic method that we applied to 14 of these genes in 290 patients with acute sciatica, whose reduction in movement was estimated by items from the Roland-Morris Disability Questionnaire. Results We genotyped a total of 121 single nucleotide polymorphisms (SNPs in 14 of these genes, which code for the dopamine D2 receptor, GTP cyclohydrolase I, glycine receptor α1 subunit, GABA-A receptor α2 subunit, GABA-A receptor β1 subunit, α-adrenergic 1C, 2A, and 2C receptors, serotonin 1A and 2A receptors, cannabinoid CB-1 receptor, M1 muscarinic receptor, and the tyrosine hydroxylase, and tachykinin precursor-1 molecules. No SNP showed a significant association with the movement score after a Bonferroni correction for the 14 genes tested. Haplotype analysis of one of the blocks in the GABA-A receptor β1 subunit showed that a haplotype of 11% frequency was associated with less limitation of movement at a nominal significance level value (p = 0.0025 almost strong enough to correct for testing 22 haplotype blocks. Conclusion If confirmed, the current results may suggest that a common haplotype in the GABA-A β1 subunit acts like an "endogenous muscle relaxant" in an individual with subacute sciatica. Similar methods might be applied a larger set of

  4. Coasting, embryo development and outcomes of blastocyst transfer: a case-control study.

    Science.gov (United States)

    Talebi Chahvar, Solmas; Zosmer, Ariel; Caragia, Alina; Balestrini, Simona; Sabatini, Luca; Tranquilli, Andrea Luigi; Al-Shawaf, Talha

    2014-08-01

    This study compared the effect on blastocyst development and clinical outcome of coasting in women at increased risk of moderate-severe ovarian hyperstimulation syndrome (OHSS; n=389) with a control group matched for age and basal FSH that did not undergo coasting (n=386) in IVF/intracytoplasmic sperm injection (ICSI) cycles. The main outcome measures were rate of blastocyst development and live birth. More cycles progressed to the blastocyst stage in the coasted group (n=169) compared with the control group (n=83; 43.4% versus 21.5%; P<0.001). The biochemical pregnancy, clinical pregnancy and live birth rates were similar (46.5% versus 42.0%; 40.6% versus 37.8%; 31.6% versus 30.1%). The duration of coasting up to 4 days did not affect progression to blastocyst stage. The multivariate model showed that coasting (OR 1.73, P=0.004) and the number of oocytes retrieved (OR 1.17, P=0.001) were positively correlated with blastocyst formation. Coasting, a measure to reduce the risk of OHSS, does not impair blastocyst development or clinical outcome. Coasting should remain an effective measure to prevent OHSS. Copyright © 2014 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  5. Risk factors for adverse driving outcomes in Dutch adults with ADHD and controls.

    Science.gov (United States)

    Bron, Tannetje I; Bijlenga, Denise; Breuk, Minda; Michielsen, Marieke; Beekman, Aartjan T F; Kooij, J J Sandra

    2018-02-01

    To identify risk factors for adverse driving outcomes and unsafe driving among adults with and without ADHD in a Dutch sample. In this cross-sectional study, validated self-report questionnaires were used to compare driving history and current driving behavior between 330 adults diagnosed with ADHD and 330 controls. Adults with ADHD had significantly more adverse driving outcomes when compared to controls. Having an ADHD diagnosis significantly increased the odds for having had 3 or more vehicular crashes (OR = 2.72; p = .001). Driving frequency, male gender, age, high anxiety levels, high hostility levels, and alcohol use all significantly influenced the odds for unsafe driving behavior, for having had 12 or more traffic citations, and/or for having had 3 or more vehicular crashes. Alcohol use, and high levels of anxiety and hostility are highly prevalent among adults with ADHD, and they mediate the risk for negative driving outcomes in this group. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Intra- versus retroplacental hematomas: a retrospective case-control study on pregnancy outcomes.

    Science.gov (United States)

    Ott, Johannes; Pecnik, Philipp; Promberger, Regina; Pils, Sophie; Binder, Julia; Chalubinski, Kinga M

    2017-10-26

    Intrauterine hemato