Aperture averaging in strong oceanic turbulence

NASA Astrophysics Data System (ADS)

Gökçe, Muhsin Caner; Baykal, Yahya

2018-04-01

Receiver aperture averaging technique is employed in underwater wireless optical communication (UWOC) systems to mitigate the effects of oceanic turbulence, thus to improve the system performance. The irradiance flux variance is a measure of the intensity fluctuations on a lens of the receiver aperture. Using the modified Rytov theory which uses the small-scale and large-scale spatial filters, and our previously presented expression that shows the atmospheric structure constant in terms of oceanic turbulence parameters, we evaluate the irradiance flux variance and the aperture averaging factor of a spherical wave in strong oceanic turbulence. Irradiance flux variance variations are examined versus the oceanic turbulence parameters and the receiver aperture diameter are examined in strong oceanic turbulence. Also, the effect of the receiver aperture diameter on the aperture averaging factor is presented in strong oceanic turbulence.

One-shot estimate of MRMC variance: AUC.

PubMed

Gallas, Brandon D

2006-03-01

One popular study design for estimating the area under the receiver operating characteristic curve (AUC) is the one in which a set of readers reads a set of cases: a fully crossed design in which every reader reads every case. The variability of the subsequent reader-averaged AUC has two sources: the multiple readers and the multiple cases (MRMC). In this article, we present a nonparametric estimate for the variance of the reader-averaged AUC that is unbiased and does not use resampling tools. The one-shot estimate is based on the MRMC variance derived by the mechanistic approach of Barrett et al. (2005), as well as the nonparametric variance of a single-reader AUC derived in the literature on U statistics. We investigate the bias and variance properties of the one-shot estimate through a set of Monte Carlo simulations with simulated model observers and images. The different simulation configurations vary numbers of readers and cases, amounts of image noise and internal noise, as well as how the readers are constructed. We compare the one-shot estimate to a method that uses the jackknife resampling technique with an analysis of variance model at its foundation (Dorfman et al. 1992). The name one-shot highlights that resampling is not used. The one-shot and jackknife estimators behave similarly, with the one-shot being marginally more efficient when the number of cases is small. We have derived a one-shot estimate of the MRMC variance of AUC that is based on a probabilistic foundation with limited assumptions, is unbiased, and compares favorably to an established estimate.

Justifying scale type for a latent variable: Formative or reflective?

NASA Astrophysics Data System (ADS)

Liu, Hao; Bahron, Arsiah; Bagul, Awangku Hassanal Bahar Pengiran

2015-12-01

The study attempted to explore the possibilities to create a procedure at the experimental level to double confirm whether manifest variables scale type is formative or reflective. Now, the criteria of making such a decision are heavily depended on researchers' judgment at the conceptual and operational level. The study created an experimental procedure that seems could double confirm the decisions from the conceptual and operational level judgments. The experimental procedure includes the following tests, Variance Inflation Factor (VIF), Tolerance (TOL), Ridge Regression, Cronbach's alpha, Dillon-Goldstein's rho, and first and second eigenvalue. The procedure considers manifest variables' both multicollinearity and consistency. As the result, the procedure received the same judgment with the carefully established decision making at the concept and operational level.

Waveform Design and Diversity for Advanced Space-Time Adaptive Processing and Multiple Input Multiple Output Systems

DTIC Science & Technology

2012-08-01

It suggests that a smart use of some a-priori information about the operating environment, when processing the received signal and designing the...random variable with the same variance of the backscattering target amplitude αT , and D ( αT , α G T ) is the Kullback − Leibler divergence, see [65...MI . Proof. See Appendix 3.6.6. Thus, we can use the optimization procedure of Algorithm 4 to optimize the Mutual Information between the target

Thermal noise variance of a receive radiofrequency coil as a respiratory motion sensor.

PubMed

Andreychenko, A; Raaijmakers, A J E; Sbrizzi, A; Crijns, S P M; Lagendijk, J J W; Luijten, P R; van den Berg, C A T

2017-01-01

Development of a passive respiratory motion sensor based on the noise variance of the receive coil array. Respiratory motion alters the body resistance. The noise variance of an RF coil depends on the body resistance and, thus, is also modulated by respiration. For the noise variance monitoring, the noise samples were acquired without and with MR signal excitation on clinical 1.5/3 T MR scanners. The performance of the noise sensor was compared with the respiratory bellow and with the diaphragm displacement visible on MR images. Several breathing patterns were tested. The noise variance demonstrated a periodic, temporal modulation that was synchronized with the respiratory bellow signal. The modulation depth of the noise variance resulting from the respiration varied between the channels of the array and depended on the channel's location with respect to the body. The noise sensor combined with MR acquisition was able to detect the respiratory motion for every k-space read-out line. Within clinical MR systems, the respiratory motion can be detected by the noise in receive array. The noise sensor does not require careful positioning unlike the bellow, any additional hardware, and/or MR acquisition. Magn Reson Med 77:221-228, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Comparing two correlated C indices with right-censored survival outcome: a one-shot nonparametric approach.

PubMed

Kang, Le; Chen, Weijie; Petrick, Nicholas A; Gallas, Brandon D

2015-02-20

The area under the receiver operating characteristic curve is often used as a summary index of the diagnostic ability in evaluating biomarkers when the clinical outcome (truth) is binary. When the clinical outcome is right-censored survival time, the C index, motivated as an extension of area under the receiver operating characteristic curve, has been proposed by Harrell as a measure of concordance between a predictive biomarker and the right-censored survival outcome. In this work, we investigate methods for statistical comparison of two diagnostic or predictive systems, of which they could either be two biomarkers or two fixed algorithms, in terms of their C indices. We adopt a U-statistics-based C estimator that is asymptotically normal and develop a nonparametric analytical approach to estimate the variance of the C estimator and the covariance of two C estimators. A z-score test is then constructed to compare the two C indices. We validate our one-shot nonparametric method via simulation studies in terms of the type I error rate and power. We also compare our one-shot method with resampling methods including the jackknife and the bootstrap. Simulation results show that the proposed one-shot method provides almost unbiased variance estimations and has satisfactory type I error control and power. Finally, we illustrate the use of the proposed method with an example from the Framingham Heart Study. Copyright © 2014 John Wiley & Sons, Ltd.

Differences in Growth Reading Patterns for at-Risk Spanish-Monolingual Children as a Function of a Tier 2 Intervention.

PubMed

Crespo, Patricia; Jiménez, Juan E; Rodríguez, Cristina; Baker, Doris; Park, Yonghan

2018-03-09

The present study compares the patterns of growth of beginning reading skills (i.e., phonemic awareness, phonics, fluency, vocabulary and comprehension) of Spanish speaking monolingual students who received a Tier 2 reading intervention with students who did not receive the intervention. All the students in grades K-2 were screened at the beginning of the year to confirm their risk status. A quasi-experimental longitudinal design was used: the treatment group received a supplemental program in small groups of 3 to 5 students, for 30 minutes daily from November to June. The control group did not receive it. All students were assessed three times during the academic year. A hierarchical linear growth modeling was conducted and differences on growth rate were found in vocabulary in kindergarten (p < .001; variance explained = 77.0%), phonemic awareness in kindergarten (p < .001; variance explained = 43.7%) and first grade (p < .01; variance explained = 15.2%), and finally we also find significant growth differences for second grade in oral reading fluency (p < .05; variance explained = 15.1%) and retell task (p < .05; variance explained = 14.5%). Children at risk for reading disabilities in Spanish can improve their skills when they receive explicit instruction in the context of Response to Intervention (RtI). Findings are discussed for each skill in the context of implementing a Tier 2 small group intervention within an RtI approach. Implications for practice in the Spanish educational context are also discussed for children who are struggling with reading.

Drought and Heat Wave Impacts on Electricity Grid Reliability in Illinois

NASA Astrophysics Data System (ADS)

Stillwell, A. S.; Lubega, W. N.

2016-12-01

A large proportion of thermal power plants in the United States use cooling systems that discharge large volumes of heated water into rivers and cooling ponds. To minimize thermal pollution from these discharges, restrictions are placed on temperatures at the edge of defined mixing zones in the receiving waters. However, during extended hydrological droughts and heat waves, power plants are often granted thermal variances permitting them to exceed these temperature restrictions. These thermal variances are often deemed necessary for maintaining electricity reliability, particularly as heat waves cause increased electricity demand. Current practice, however, lacks tools for the development of grid-scale operational policies specifying generator output levels that ensure reliable electricity supply while minimizing thermal variances. Such policies must take into consideration characteristics of individual power plants, topology and characteristics of the electricity grid, and locations of power plants within the river basin. In this work, we develop a methodology for the development of these operational policies that captures necessary factors. We develop optimal rules for different hydrological and meteorological conditions, serving as rule curves for thermal power plants. The rules are conditioned on leading modes of the ambient hydrological and meteorological conditions at the different power plant locations, as the locations are geographically close and hydrologically connected. Heat dissipation in the rivers and cooling ponds is modeled using the equilibrium temperature concept. Optimal rules are determined through a Monte Carlo sampling optimization framework. The methodology is applied to a case study of eight power plants in Illinois that were granted thermal variances in the summer of 2012, with a representative electricity grid model used in place of the actual electricity grid.

Threshold detection in an on-off binary communications channel with atmospheric scintillation

NASA Technical Reports Server (NTRS)

Webb, W. E.; Marino, J. T., Jr.

1974-01-01

The optimum detection threshold in an on-off binary optical communications system operating in the presence of atmospheric turbulence was investigated assuming a poisson detection process and log normal scintillation. The dependence of the probability of bit error on log amplitude variance and received signal strength was analyzed and semi-emperical relationships to predict the optimum detection threshold derived. On the basis of this analysis a piecewise linear model for an adaptive threshold detection system is presented. Bit error probabilities for non-optimum threshold detection system were also investigated.

Threshold detection in an on-off binary communications channel with atmospheric scintillation

NASA Technical Reports Server (NTRS)

Webb, W. E.

1975-01-01

The optimum detection threshold in an on-off binary optical communications system operating in the presence of atmospheric turbulence was investigated assuming a poisson detection process and log normal scintillation. The dependence of the probability of bit error on log amplitude variance and received signal strength was analyzed and semi-empirical relationships to predict the optimum detection threshold derived. On the basis of this analysis a piecewise linear model for an adaptive threshold detection system is presented. The bit error probabilities for nonoptimum threshold detection systems were also investigated.

40 CFR 190.11 - Variances for unusual operations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Variances for unusual operations. 190.11 Section 190.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) RADIATION PROTECTION PROGRAMS ENVIRONMENTAL RADIATION PROTECTION STANDARDS FOR NUCLEAR POWER OPERATIONS Environmental...

40 CFR 190.11 - Variances for unusual operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Variances for unusual operations. 190.11 Section 190.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) RADIATION PROTECTION PROGRAMS ENVIRONMENTAL RADIATION PROTECTION STANDARDS FOR NUCLEAR POWER OPERATIONS Environmental...

40 CFR 190.11 - Variances for unusual operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Variances for unusual operations. 190.11 Section 190.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) RADIATION PROTECTION PROGRAMS ENVIRONMENTAL RADIATION PROTECTION STANDARDS FOR NUCLEAR POWER OPERATIONS Environmental...

40 CFR 190.11 - Variances for unusual operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Variances for unusual operations. 190.11 Section 190.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) RADIATION PROTECTION PROGRAMS ENVIRONMENTAL RADIATION PROTECTION STANDARDS FOR NUCLEAR POWER OPERATIONS Environmental...

40 CFR 190.11 - Variances for unusual operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Variances for unusual operations. 190.11 Section 190.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) RADIATION PROTECTION PROGRAMS ENVIRONMENTAL RADIATION PROTECTION STANDARDS FOR NUCLEAR POWER OPERATIONS Environmental...

Feasibility of histogram analysis of susceptibility-weighted MRI for staging of liver fibrosis

PubMed Central

Yang, Zhao-Xia; Liang, He-Yue; Hu, Xin-Xing; Huang, Ya-Qin; Ding, Ying; Yang, Shan; Zeng, Meng-Su; Rao, Sheng-Xiang

2016-01-01

PURPOSE We aimed to evaluate whether histogram analysis of susceptibility-weighted imaging (SWI) could quantify liver fibrosis grade in patients with chronic liver disease (CLD). METHODS Fifty-three patients with CLD who underwent multi-echo SWI (TEs of 2.5, 5, and 10 ms) were included. Histogram analysis of SWI images were performed and mean, variance, skewness, kurtosis, and the 1st, 10th, 50th, 90th, and 99th percentiles were derived. Quantitative histogram parameters were compared. For significant parameters, further receiver operating characteristic (ROC) analyses were performed to evaluate the potential diagnostic performance for differentiating liver fibrosis stages. RESULTS The number of patients in each pathologic fibrosis grade was 7, 3, 5, 5, and 33 for F0, F1, F2, F3, and F4, respectively. The results of variance (TE: 10 ms), 90th percentile (TE: 10 ms), and 99th percentile (TE: 10 and 5 ms) in F0–F3 group were significantly lower than in F4 group, with areas under the ROC curves (AUCs) of 0.84 for variance and 0.70–0.73 for the 90th and 99th percentiles, respectively. The results of variance (TE: 10 and 5 ms), 99th percentile (TE: 10 ms), and skewness (TE: 2.5 and 5 ms) in F0–F2 group were smaller than those of F3/F4 group, with AUCs of 0.88 and 0.69 for variance (TE: 10 and 5 ms, respectively), 0.68 for 99th percentile (TE: 10 ms), and 0.73 and 0.68 for skewness (TE: 2.5 and 5 ms, respectively). CONCLUSION Magnetic resonance histogram analysis of SWI, particularly the variance, is promising for predicting advanced liver fibrosis and cirrhosis. PMID:27113421

Three tests and three corrections: Comment on Koen and Yonelinas (2010)

PubMed Central

Jang, Yoonhee; Mickes, Laura; Wixted, John T.

2012-01-01

The slope of the z-transformed receiver-operating characteristic (zROC) in recognition memory experiments is usually less than 1, which has long been interpreted to mean that the variance of the target distribution is greater than the variance of the lure distribution. The greater variance of the target distribution could arise because the different items on a list receive different increments in memory strength during study (the “encoding variability” hypothesis). In a test of that interpretation, J. Koen and A. Yonelinas (2010, K&Y) attempted to further increase encoding variability to see if it would further decrease the slope of the zROC. To do so, they presented items on a list for two different durations and then mixed the weak and strong targets together. After performing three tests on the mixed-strength data, K&Y concluded that encoding variability does not explain why the slope of the zROC is typically less than one. However, we show that their tests have no bearing on the encoding variability account. Instead, they bear on the mixture-UVSD model that corresponds to their experimental design. On the surface, the results reported by K&Y appear to be inconsistent with the predictions of the mixture-UVSD model (though they were taken to be inconsistent with the predictions of the encoding variability hypothesis). However, all three of the tests they performed contained errors. When those errors are corrected, the same three tests show that their data support, rather than contradict, the mixture-UVSD model (but they still have no bearing on the encoding variability hypothesis). PMID:22390323

Evaluation of hyperglycaemic response to intra-operative dexamethasone administration in patients undergoing elective intracranial surgery: A randomised, prospective study.

PubMed

Sethi, Rakesh; Naqash, Imtiaz A; Bajwa, Sukhminder Jit Singh; Dutta, Vikas; Ramzan, Altaf Umar; Zahoor, Syed Amir

2016-01-01

The glucocorticoid dexamethasone in a bolus dose of 8-10 mg followed by quarterly dose of 4 mg is commonly used during intracranial surgery so as to reduce oedema and vascular permeability. However, the detrimental hyperglycaemic effects of dexamethasone may override its potentially beneficial effects. The present prospective, randomised study aimed at comparing the degree and magnitude of hyperglycaemia induced by prophylactic administration of dexamethasone in patients undergoing elective craniotomy. Sixty American Society of Anaesthesiologist (ASA) grade-I and II patients were randomly assigned to three groups of 20 patients each. Group-I received dexamethasone during surgery for the first time. Group-II received dexamethasone in addition to receiving it pre-operatively, whereas Group-III (control group) patients were administered normal saline as placebo. Baseline blood glucose (BG) was measured in all the three groups before induction of anaesthesia and thereafter after every hour for 4 h and then two-hourly. Besides intra- and intergroup comparison of BG, peak BG concentration was also recorded for each patient. Statistical analysis was carried out with analysis of variance (ANOVA) and Student's t-test and value of P < 0.05 was considered statistically significant. Baseline BG reading were higher and statistically significant in Group-II as compared with Group-I and Group-III (P < 0.05). However, peak BG levels were significantly higher in Group-I than in Group-II and III (P < 0.05). Similarly, the magnitude of change in peak BG was significantly higher in Group-I as compared to Group-II and III (P < 0.05). Peri-operative administration of dexamethasone during neurosurgical procedures can cause significant increase in BG concentration especially in patients who receive dexamethasone intra-operatively only.

Evaluation of hyperglycaemic response to intra-operative dexamethasone administration in patients undergoing elective intracranial surgery: A randomised, prospective study

PubMed Central

Sethi, Rakesh; Naqash, Imtiaz A.; Bajwa, Sukhminder Jit Singh; Dutta, Vikas; Ramzan, Altaf Umar; Zahoor, Syed Amir

2016-01-01

Background and Aim: The glucocorticoid dexamethasone in a bolus dose of 8-10 mg followed by quarterly dose of 4 mg is commonly used during intracranial surgery so as to reduce oedema and vascular permeability. However, the detrimental hyperglycaemic effects of dexamethasone may override its potentially beneficial effects. The present prospective, randomised study aimed at comparing the degree and magnitude of hyperglycaemia induced by prophylactic administration of dexamethasone in patients undergoing elective craniotomy. Materials and Methods: Sixty American Society of Anaesthesiologist (ASA) grade-I and II patients were randomly assigned to three groups of 20 patients each. Group-I received dexamethasone during surgery for the first time. Group-II received dexamethasone in addition to receiving it pre-operatively, whereas Group-III (control group) patients were administered normal saline as placebo. Baseline blood glucose (BG) was measured in all the three groups before induction of anaesthesia and thereafter after every hour for 4 h and then two-hourly. Besides intra- and intergroup comparison of BG, peak BG concentration was also recorded for each patient. Statistical analysis was carried out with analysis of variance (ANOVA) and Student's t-test and value of P < 0.05 was considered statistically significant. Results: Baseline BG reading were higher and statistically significant in Group-II as compared with Group-I and Group-III (P < 0.05). However, peak BG levels were significantly higher in Group-I than in Group-II and III (P < 0.05). Similarly, the magnitude of change in peak BG was significantly higher in Group-I as compared to Group-II and III (P < 0.05). Conclusion: Peri-operative administration of dexamethasone during neurosurgical procedures can cause significant increase in BG concentration especially in patients who receive dexamethasone intra-operatively only. PMID:27057213

Easy and accurate variance estimation of the nonparametric estimator of the partial area under the ROC curve and its application.

PubMed

Yu, Jihnhee; Yang, Luge; Vexler, Albert; Hutson, Alan D

2016-06-15

The receiver operating characteristic (ROC) curve is a popular technique with applications, for example, investigating an accuracy of a biomarker to delineate between disease and non-disease groups. A common measure of accuracy of a given diagnostic marker is the area under the ROC curve (AUC). In contrast with the AUC, the partial area under the ROC curve (pAUC) looks into the area with certain specificities (i.e., true negative rate) only, and it can be often clinically more relevant than examining the entire ROC curve. The pAUC is commonly estimated based on a U-statistic with the plug-in sample quantile, making the estimator a non-traditional U-statistic. In this article, we propose an accurate and easy method to obtain the variance of the nonparametric pAUC estimator. The proposed method is easy to implement for both one biomarker test and the comparison of two correlated biomarkers because it simply adapts the existing variance estimator of U-statistics. In this article, we show accuracy and other advantages of the proposed variance estimation method by broadly comparing it with previously existing methods. Further, we develop an empirical likelihood inference method based on the proposed variance estimator through a simple implementation. In an application, we demonstrate that, depending on the inferences by either the AUC or pAUC, we can make a different decision on a prognostic ability of a same set of biomarkers. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Synchronization using pulsed edge tracking in optical PPM communication system

NASA Technical Reports Server (NTRS)

Gagliardi, R.

1972-01-01

A pulse position modulated (PPM) optical communication system using narrow pulses of light for data transmission requires accurate time synchronization between transmitter and receiver. The presence of signal energy in the form of optical pulses suggests the use of a pulse edge tracking method of maintaining the necessary timing. The edge tracking operation in a binary PPM system is examined, taking into account the quantum nature of the optical transmissions. Consideration is given first to pure synchronization using a periodic pulsed intensity, then extended to the case where position modulation is present and auxiliary bit decisioning is needed to aid the tracking operation. Performance analysis is made in terms of timing error and its associated statistics. Timing error variances are shown as a function of system signal to noise ratio.

Fuel cell stack monitoring and system control

DOEpatents

Keskula, Donald H.; Doan, Tien M.; Clingerman, Bruce J.

2005-01-25

A control method for monitoring a fuel cell stack in a fuel cell system in which the actual voltage and actual current from the fuel cell stack are monitored. A preestablished relationship between voltage and current over the operating range of the fuel cell is established. A variance value between the actual measured voltage and the expected voltage magnitude for a given actual measured current is calculated and compared with a predetermined allowable variance. An output is generated if the calculated variance value exceeds the predetermined variance. The predetermined voltage-current for the fuel cell is symbolized as a polarization curve at given operating conditions of the fuel cell. Other polarization curves may be generated and used for fuel cell stack monitoring based on different operating pressures, temperatures, hydrogen quantities.

Robust transceiver design for reciprocal M × N interference channel based on statistical linearization approximation

NASA Astrophysics Data System (ADS)

Mayvan, Ali D.; Aghaeinia, Hassan; Kazemi, Mohammad

2017-12-01

This paper focuses on robust transceiver design for throughput enhancement on the interference channel (IC), under imperfect channel state information (CSI). In this paper, two algorithms are proposed to improve the throughput of the multi-input multi-output (MIMO) IC. Each transmitter and receiver has, respectively, M and N antennas and IC operates in a time division duplex mode. In the first proposed algorithm, each transceiver adjusts its filter to maximize the expected value of signal-to-interference-plus-noise ratio (SINR). On the other hand, the second algorithm tries to minimize the variances of the SINRs to hedge against the variability due to CSI error. Taylor expansion is exploited to approximate the effect of CSI imperfection on mean and variance. The proposed robust algorithms utilize the reciprocity of wireless networks to optimize the estimated statistical properties in two different working modes. Monte Carlo simulations are employed to investigate sum rate performance of the proposed algorithms and the advantage of incorporating variation minimization into the transceiver design.

Likelihood Ratio, Optimal Decision Rules, and Relationship between Proportion Correct and d' in the Dual-Pair AB vs BA identification Paradigm

PubMed Central

Micheyl, Christophe; Dai, Huanping

2010-01-01

The equal-variance Gaussian signal-detection-theory (SDT) decision model for the dual-pair change-detection (or “4IAX”) paradigm has been described in earlier publications. In this note, we consider the equal-variance Gaussian SDT model for the related dual-pair AB vs BA identification paradigm. The likelihood ratios, optimal decision rules, receiver operating characteristics (ROCs), and relationships between d' and proportion-correct (PC) are analyzed for two special cases: that of statistically independent observations, which is likely to apply in constant-stimuli experiments, and that of highly correlated observations, which is likely to apply in experiments where stimuli are roved widely across trials or pairs. A surprising outcome of this analysis is that although these two situations lead to different optimal decision rules, the predicted ROCs and proportions of correct responses (PCs) for these two cases are not substantially different, and are either identical or similar to those observed in the basic Yes-No paradigm. PMID:19633356

A geometrical optics approach for modeling aperture averaging in free space optical communication applications

NASA Astrophysics Data System (ADS)

Yuksel, Heba; Davis, Christopher C.

2006-09-01

Intensity fluctuations at the receiver in free space optical (FSO) communication links lead to a received power variance that depends on the size of the receiver aperture. Increasing the size of the receiver aperture reduces the power variance. This effect of the receiver size on power variance is called aperture averaging. If there were no aperture size limitation at the receiver, then there would be no turbulence-induced scintillation. In practice, there is always a tradeoff between aperture size, transceiver weight, and potential transceiver agility for pointing, acquisition and tracking (PAT) of FSO communication links. We have developed a geometrical simulation model to predict the aperture averaging factor. This model is used to simulate the aperture averaging effect at given range by using a large number of rays, Gaussian as well as uniformly distributed, propagating through simulated turbulence into a circular receiver of varying aperture size. Turbulence is simulated by filling the propagation path with spherical bubbles of varying sizes and refractive index discontinuities statistically distributed according to various models. For each statistical representation of the atmosphere, the three-dimensional trajectory of each ray is analyzed using geometrical optics. These Monte Carlo techniques have proved capable of assessing the aperture averaging effect, in particular, the quantitative expected reduction in intensity fluctuations with increasing aperture diameter. In addition, beam wander results have demonstrated the range-cubed dependence of mean-squared beam wander. An effective turbulence parameter can also be determined by correlating beam wander behavior with the path length.

Fuel cell stack monitoring and system control

DOEpatents

Keskula, Donald H.; Doan, Tien M.; Clingerman, Bruce J.

2004-02-17

A control method for monitoring a fuel cell stack in a fuel cell system in which the actual voltage and actual current from the fuel cell stack are monitored. A preestablished relationship between voltage and current over the operating range of the fuel cell is established. A variance value between the actual measured voltage and the expected voltage magnitude for a given actual measured current is calculated and compared with a predetermined allowable variance. An output is generated if the calculated variance value exceeds the predetermined variance. The predetermined voltage-current for the fuel cell is symbolized as a polarization curve at given operating conditions of the fuel cell.

25 CFR 542.18 - How does a gaming operation apply for a variance from the standards of the part?

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false How does a gaming operation apply for a variance from the standards of the part? 542.18 Section 542.18 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR HUMAN SERVICES MINIMUM INTERNAL CONTROL STANDARDS § 542.18 How does a gaming operation apply for a...

40 CFR 142.307 - What terms and conditions must be included in a small system variance?

Code of Federal Regulations, 2010 CFR

2010-07-01

... that may affect proper and effective operation and maintenance of the technology; (2) Monitoring... effective installation, operation and maintenance of the applicable small system variance technology in... health, which may include: (i) Public education requirements; and (ii) Source water protection...

75 FR 6220 - Information Collection Requirements for the Variance Regulations; Submission for Office of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-08

... DEPARTMENT OF LABOR Occupational Safety and Health Administration [Docket No. OSHA-2009-0024... national defense variances. DATES: Comments must be submitted (postmarked, transmitted, or received) by... not transmit attachments (e.g., studies, journal articles), they must submit one hard copy of the...

3D facial landmarks: Inter-operator variability of manual annotation

PubMed Central

2014-01-01

Background Manual annotation of landmarks is a known source of variance, which exist in all fields of medical imaging, influencing the accuracy and interpretation of the results. However, the variability of human facial landmarks is only sparsely addressed in the current literature as opposed to e.g. the research fields of orthodontics and cephalometrics. We present a full facial 3D annotation procedure and a sparse set of manually annotated landmarks, in effort to reduce operator time and minimize the variance. Method Facial scans from 36 voluntary unrelated blood donors from the Danish Blood Donor Study was randomly chosen. Six operators twice manually annotated 73 anatomical and pseudo-landmarks, using a three-step scheme producing a dense point correspondence map. We analyzed both the intra- and inter-operator variability, using mixed-model ANOVA. We then compared four sparse sets of landmarks in order to construct a dense correspondence map of the 3D scans with a minimum point variance. Results The anatomical landmarks of the eye were associated with the lowest variance, particularly the center of the pupils. Whereas points of the jaw and eyebrows have the highest variation. We see marginal variability in regards to intra-operator and portraits. Using a sparse set of landmarks (n=14), that capture the whole face, the dense point mean variance was reduced from 1.92 to 0.54 mm. Conclusion The inter-operator variability was primarily associated with particular landmarks, where more leniently landmarks had the highest variability. The variables embedded in the portray and the reliability of a trained operator did only have marginal influence on the variability. Further, using 14 of the annotated landmarks we were able to reduced the variability and create a dense correspondences mesh to capture all facial features. PMID:25306436

The Agreement between Auscultation and Lung Ultrasound in Hemodialysis Patients: The LUST Study.

PubMed

Torino, Claudia; Gargani, Luna; Sicari, Rosa; Letachowicz, Krzysztof; Ekart, Robert; Fliser, Danilo; Covic, Adrian; Siamopoulos, Kostas; Stavroulopoulos, Aristeidis; Massy, Ziad A; Fiaccadori, Enrico; Caiazza, Alberto; Bachelet, Thomas; Slotki, Itzchak; Martinez-Castelao, Alberto; Coudert-Krier, Marie-Jeanne; Rossignol, Patrick; Gueler, Faikah; Hannedouche, Thierry; Panichi, Vincenzo; Wiecek, Andrzej; Pontoriero, Giuseppe; Sarafidis, Pantelis; Klinger, Marian; Hojs, Radovan; Seiler-Mussler, Sarah; Lizzi, Fabio; Siriopol, Dimitrie; Balafa, Olga; Shavit, Linda; Tripepi, Rocco; Mallamaci, Francesca; Tripepi, Giovanni; Picano, Eugenio; London, Gérard Michel; Zoccali, Carmine

2016-11-07

Accumulation of fluid in the lung is the most concerning sequela of volume expansion in patients with ESRD. Lung auscultation is recommended to detect and monitor pulmonary congestion, but its reliability in ESRD is unknown. In a subproject of the ongoing Lung Water by Ultra-Sound Guided Treatment to Prevent Death and Cardiovascular Complications in High Risk ESRD Patients with Cardiomyopathy Trial, we compared a lung ultrasound-guided ultrafiltration prescription policy versus standard care in high-risk patients on hemodialysis. The reliability of peripheral edema was tested as well. This study was on the basis of 1106 pre- and postdialysis lung ultrasound studies (in 79 patients) simultaneous with standardized lung auscultation (crackles at the lung bases) and quantification of peripheral edema. Lung congestion by crackles, edema, or a combination thereof poorly reflected the severity of congestion as detected by ultrasound B lines in various analyses, including standard regression analysis weighting for repeated measures in individual patients (shared variance of 12% and 4% for crackles and edema, respectively) and κ-statistics (κ ranging from 0.00 to 0.16). In general, auscultation had very low discriminatory power for the diagnosis of mild (area under the receiver operating curve =0.61), moderate (area under the receiver operating curve =0.65), and severe (area under the receiver operating curve =0.68) lung congestion, and the same was true for peripheral edema (receiver operating curve =0.56 or lower) and the combination of the two physical signs. Lung crackles, either alone or combined with peripheral edema, very poorly reflect interstitial lung edema in patients with ESRD. These findings reinforce the rationale underlying the Lung Water by Ultra-Sound Guided Treatment to Prevent Death and Cardiovascular Complications in High Risk ESRD Patients with Cardiomyopathy Trial, a trial adopting ultrasound B lines as an instrument to guide interventions aimed at mitigating lung congestion in high-risk patients on hemodialysis. Copyright © 2016 by the American Society of Nephrology.

The Agreement between Auscultation and Lung Ultrasound in Hemodialysis Patients: The LUST Study

PubMed Central

Torino, Claudia; Gargani, Luna; Sicari, Rosa; Letachowicz, Krzysztof; Ekart, Robert; Fliser, Danilo; Covic, Adrian; Siamopoulos, Kostas; Stavroulopoulos, Aristeidis; Massy, Ziad A.; Fiaccadori, Enrico; Caiazza, Alberto; Bachelet, Thomas; Slotki, Itzchak; Martinez-Castelao, Alberto; Coudert-Krier, Marie-Jeanne; Rossignol, Patrick; Gueler, Faikah; Hannedouche, Thierry; Panichi, Vincenzo; Wiecek, Andrzej; Pontoriero, Giuseppe; Sarafidis, Pantelis; Klinger, Marian; Hojs, Radovan; Seiler-Mussler, Sarah; Lizzi, Fabio; Siriopol, Dimitrie; Balafa, Olga; Shavit, Linda; Tripepi, Rocco; Mallamaci, Francesca; Tripepi, Giovanni; Picano, Eugenio; London, Gérard Michel

2016-01-01

Background and objectives Accumulation of fluid in the lung is the most concerning sequela of volume expansion in patients with ESRD. Lung auscultation is recommended to detect and monitor pulmonary congestion, but its reliability in ESRD is unknown. Design, setting, participants, & measurements In a subproject of the ongoing Lung Water by Ultra-Sound Guided Treatment to Prevent Death and Cardiovascular Complications in High Risk ESRD Patients with Cardiomyopathy Trial, we compared a lung ultrasound–guided ultrafiltration prescription policy versus standard care in high-risk patients on hemodialysis. The reliability of peripheral edema was tested as well. This study was on the basis of 1106 pre– and postdialysis lung ultrasound studies (in 79 patients) simultaneous with standardized lung auscultation (crackles at the lung bases) and quantification of peripheral edema. Results Lung congestion by crackles, edema, or a combination thereof poorly reflected the severity of congestion as detected by ultrasound B lines in various analyses, including standard regression analysis weighting for repeated measures in individual patients (shared variance of 12% and 4% for crackles and edema, respectively) and κ-statistics (κ ranging from 0.00 to 0.16). In general, auscultation had very low discriminatory power for the diagnosis of mild (area under the receiver operating curve =0.61), moderate (area under the receiver operating curve =0.65), and severe (area under the receiver operating curve =0.68) lung congestion, and the same was true for peripheral edema (receiver operating curve =0.56 or lower) and the combination of the two physical signs. Conclusions Lung crackles, either alone or combined with peripheral edema, very poorly reflect interstitial lung edema in patients with ESRD. These findings reinforce the rationale underlying the Lung Water by Ultra-Sound Guided Treatment to Prevent Death and Cardiovascular Complications in High Risk ESRD Patients with Cardiomyopathy Trial, a trial adopting ultrasound B lines as an instrument to guide interventions aimed at mitigating lung congestion in high-risk patients on hemodialysis. PMID:27660305

Inter-operator Reliability of Magnetic Resonance Image-Based Computational Fluid Dynamics Prediction of Cerebrospinal Fluid Motion in the Cervical Spine.

PubMed

Martin, Bryn A; Yiallourou, Theresia I; Pahlavian, Soroush Heidari; Thyagaraj, Suraj; Bunck, Alexander C; Loth, Francis; Sheffer, Daniel B; Kröger, Jan Robert; Stergiopulos, Nikolaos

2016-05-01

For the first time, inter-operator dependence of MRI based computational fluid dynamics (CFD) modeling of cerebrospinal fluid (CSF) in the cervical spinal subarachnoid space (SSS) is evaluated. In vivo MRI flow measurements and anatomy MRI images were obtained at the cervico-medullary junction of a healthy subject and a Chiari I malformation patient. 3D anatomies of the SSS were reconstructed by manual segmentation by four independent operators for both cases. CFD results were compared at nine axial locations along the SSS in terms of hydrodynamic and geometric parameters. Intraclass correlation (ICC) assessed the inter-operator agreement for each parameter over the axial locations and coefficient of variance (CV) compared the percentage of variance for each parameter between the operators. Greater operator dependence was found for the patient (0.19 < ICC < 0.99) near the craniovertebral junction compared to the healthy subject (ICC > 0.78). For the healthy subject, hydraulic diameter and Womersley number had the least variance (CV = ~2%). For the patient, peak diastolic velocity and Reynolds number had the smallest variance (CV = ~3%). These results show a high degree of inter-operator reliability for MRI-based CFD simulations of CSF flow in the cervical spine for healthy subjects and a lower degree of reliability for patients with Type I Chiari malformation.

Inter-Operator Dependence of Magnetic Resonance Image-Based Computational Fluid Dynamics Prediction of Cerebrospinal Fluid Motion in the Cervical Spine

PubMed Central

Martin, Bryn A.; Yiallourou, Theresia I.; Pahlavian, Soroush Heidari; Thyagaraj, Suraj; Bunck, Alexander C.; Loth, Francis; Sheffer, Daniel B.; Kröger, Jan Robert; Stergiopulos, Nikolaos

2015-01-01

For the first time, inter-operator dependence of MRI based computational fluid dynamics (CFD) modeling of cerebrospinal fluid (CSF) in the cervical spinal subarachnoid space (SSS) is evaluated. In vivo MRI flow measurements and anatomy MRI images were obtained at the cervico-medullary junction of a healthy subject and a Chiari I malformation patient. 3D anatomies of the SSS were reconstructed by manual segmentation by four independent operators for both cases. CFD results were compared at nine axial locations along the SSS in terms of hydrodynamic and geometric parameters. Intraclass correlation (ICC) assessed the inter-operator agreement for each parameter over the axial locations and coefficient of variance (CV) compared the percentage of variance for each parameter between the operators. Greater operator dependence was found for the patient (0.19 0.78). For the healthy subject, hydraulic diameter and Womersley number had the least variance (CV= ~2%). For the patient, peak diastolic velocity and Reynolds number had the smallest variance (CV= ~3%). These results show a high degree of inter-operator reliability for MRI-based CFD simulations of CSF flow in the cervical spine for healthy subjects and a lower degree of reliability for patients with Type I Chiari malformation. PMID:26446009

The Genetic Interpretation of Area under the ROC Curve in Genomic Profiling

PubMed Central

Wray, Naomi R.; Yang, Jian; Goddard, Michael E.; Visscher, Peter M.

2010-01-01

Genome-wide association studies in human populations have facilitated the creation of genomic profiles which combine the effects of many associated genetic variants to predict risk of disease. The area under the receiver operator characteristic (ROC) curve is a well established measure for determining the efficacy of tests in correctly classifying diseased and non-diseased individuals. We use quantitative genetics theory to provide insight into the genetic interpretation of the area under the ROC curve (AUC) when the test classifier is a predictor of genetic risk. Even when the proportion of genetic variance explained by the test is 100%, there is a maximum value for AUC that depends on the genetic epidemiology of the disease, i.e. either the sibling recurrence risk or heritability and disease prevalence. We derive an equation relating maximum AUC to heritability and disease prevalence. The expression can be reversed to calculate the proportion of genetic variance explained given AUC, disease prevalence, and heritability. We use published estimates of disease prevalence and sibling recurrence risk for 17 complex genetic diseases to calculate the proportion of genetic variance that a test must explain to achieve AUC = 0.75; this varied from 0.10 to 0.74. We provide a genetic interpretation of AUC for use with predictors of genetic risk based on genomic profiles. We provide a strategy to estimate proportion of genetic variance explained on the liability scale from estimates of AUC, disease prevalence, and heritability (or sibling recurrence risk) available as an online calculator. PMID:20195508

Performance of RVGui sensor and Kodak Ektaspeed Plus film for proximal caries detection.

PubMed

Abreu, M; Mol, A; Ludlow, J B

2001-03-01

A high-resolution charge-coupled device was used to compare the diagnostic performances obtained with Trophy's new RVGui sensor and Kodak Ektaspeed Plus film with respect to caries detection. Three acquisition modes of the Trophy RVGui sensor were compared with Kodak Ektaspeed Plus film. Images of the proximal surfaces of 40 extracted posterior teeth were evaluated by 6 observers. The presence or absence of caries was scored by means of a 5-point confidence scale. The actual caries status of each surface was determined through ground-section histology. Responses were evaluated by means of receiver operating characteristic analysis. Areas under receiver operating characteristic curves (A(Z)) were assessed through analysis of variance. The mean A(Z) scores were 0.85 for film, 0.84 for the high-resolution caries mode, and 0.82 for both the low resolution caries mode and the high-resolution periodontal mode. These differences were not statistically significant (P =.70). The differences among observers also were not statistically significant (P =.23). The performance of the RVGui sensor in high- and low-resolution modes for proximal caries detection is comparable to that of Ektaspeed Plus film.

Using Lean principles to manage throughput on an inpatient rehabilitation unit.

PubMed

Chiodo, Anthony; Wilke, Ruste; Bakshi, Rishi; Craig, Anita; Duwe, Doug; Hurvitz, Edward

2012-11-01

Performance improvement is a mainstay of operations management and maintenance of certification. In this study at a University Hospital inpatient rehabilitation unit, Lean management techniques were used to manage throughput of patients into and out of the inpatient rehabilitation unit. At the start of this process, the average admission time to the rehabilitation unit was 5:00 p.m., with a median time of 3:30 p.m., and no patients received therapy on the day of admission. Within 8 mos, the mean admission time was 1:22 p.m., 50% of the patients were on the rehabilitation unit by 1:00 p.m., and more than 70% of all patients received therapy on the day of admission. Negative variance from this performance was evaluated, the identification of inefficient discharges holding up admissions as a problem was identified, and a Lean workshop was initiated. Once this problem was tackled, the prime objective of 70% of patients receiving therapy on the date of admission was consistently met. Lean management tools are effective in improving throughput on an inpatient rehabilitation unit.

Single neuron firing properties impact correlation-based population coding

PubMed Central

Hong, Sungho; Ratté, Stéphanie; Prescott, Steven A.; De Schutter, Erik

2012-01-01

Correlated spiking has been widely observed but its impact on neural coding remains controversial. Correlation arising from co-modulation of rates across neurons has been shown to vary with the firing rates of individual neurons. This translates into rate and correlation being equivalently tuned to the stimulus; under those conditions, correlated spiking does not provide information beyond that already available from individual neuron firing rates. Such correlations are irrelevant and can reduce coding efficiency by introducing redundancy. Using simulations and experiments in rat hippocampal neurons, we show here that pairs of neurons receiving correlated input also exhibit correlations arising from precise spike-time synchronization. Contrary to rate co-modulation, spike-time synchronization is unaffected by firing rate, thus enabling synchrony- and rate-based coding to operate independently. The type of output correlation depends on whether intrinsic neuron properties promote integration or coincidence detection: “ideal” integrators (with spike generation sensitive to stimulus mean) exhibit rate co-modulation whereas “ideal” coincidence detectors (with spike generation sensitive to stimulus variance) exhibit precise spike-time synchronization. Pyramidal neurons are sensitive to both stimulus mean and variance, and thus exhibit both types of output correlation proportioned according to which operating mode is dominant. Our results explain how different types of correlations arise based on how individual neurons generate spikes, and why spike-time synchronization and rate co-modulation can encode different stimulus properties. Our results also highlight the importance of neuronal properties for population-level coding insofar as neural networks can employ different coding schemes depending on the dominant operating mode of their constituent neurons. PMID:22279226

Allowing variance may enlarge the safe operating space for exploited ecosystems.

PubMed

Carpenter, Stephen R; Brock, William A; Folke, Carl; van Nes, Egbert H; Scheffer, Marten

2015-11-17

Variable flows of food, water, or other ecosystem services complicate planning. Management strategies that decrease variability and increase predictability may therefore be preferred. However, actions to decrease variance over short timescales (2-4 y), when applied continuously, may lead to long-term ecosystem changes with adverse consequences. We investigated the effects of managing short-term variance in three well-understood models of ecosystem services: lake eutrophication, harvest of a wild population, and yield of domestic herbivores on a rangeland. In all cases, actions to decrease variance can increase the risk of crossing critical ecosystem thresholds, resulting in less desirable ecosystem states. Managing to decrease short-term variance creates ecosystem fragility by changing the boundaries of safe operating spaces, suppressing information needed for adaptive management, cancelling signals of declining resilience, and removing pressures that may build tolerance of stress. Thus, the management of variance interacts strongly and inseparably with the management of resilience. By allowing for variation, learning, and flexibility while observing change, managers can detect opportunities and problems as they develop while sustaining the capacity to deal with them.

Allowing variance may enlarge the safe operating space for exploited ecosystems

PubMed Central

Carpenter, Stephen R.; Brock, William A.; Folke, Carl; van Nes, Egbert H.; Scheffer, Marten

2015-01-01

Variable flows of food, water, or other ecosystem services complicate planning. Management strategies that decrease variability and increase predictability may therefore be preferred. However, actions to decrease variance over short timescales (2–4 y), when applied continuously, may lead to long-term ecosystem changes with adverse consequences. We investigated the effects of managing short-term variance in three well-understood models of ecosystem services: lake eutrophication, harvest of a wild population, and yield of domestic herbivores on a rangeland. In all cases, actions to decrease variance can increase the risk of crossing critical ecosystem thresholds, resulting in less desirable ecosystem states. Managing to decrease short-term variance creates ecosystem fragility by changing the boundaries of safe operating spaces, suppressing information needed for adaptive management, cancelling signals of declining resilience, and removing pressures that may build tolerance of stress. Thus, the management of variance interacts strongly and inseparably with the management of resilience. By allowing for variation, learning, and flexibility while observing change, managers can detect opportunities and problems as they develop while sustaining the capacity to deal with them. PMID:26438857

Why risk is not variance: an expository note.

PubMed

Cox, Louis Anthony Tony

2008-08-01

Variance (or standard deviation) of return is widely used as a measure of risk in financial investment risk analysis applications, where mean-variance analysis is applied to calculate efficient frontiers and undominated portfolios. Why, then, do health, safety, and environmental (HS&E) and reliability engineering risk analysts insist on defining risk more flexibly, as being determined by probabilities and consequences, rather than simply by variances? This note suggests an answer by providing a simple proof that mean-variance decision making violates the principle that a rational decisionmaker should prefer higher to lower probabilities of receiving a fixed gain, all else being equal. Indeed, simply hypothesizing a continuous increasing indifference curve for mean-variance combinations at the origin is enough to imply that a decisionmaker must find unacceptable some prospects that offer a positive probability of gain and zero probability of loss. Unlike some previous analyses of limitations of variance as a risk metric, this expository note uses only simple mathematics and does not require the additional framework of von Neumann Morgenstern utility theory.

The effect of post-traumatic-stress-disorder on intra-operative analgesia in a veteran population during cataract procedures carried out using retrobulbar or topical anesthesia: a retrospective study.

PubMed

Rapoport, Yuna; Wayman, Laura L; Chomsky, Amy S

2017-06-07

A growing proportion of veterans treated at the Veterans Health Administration (VA) have a history of post-traumatic-stress-disorder (PTSD), and there exists a higher rate of PTSD amongst veterans than the general population. The purpose of this study is to determine the correlation between PTSD and intra-operative analgesia, intra-operative time, and anesthesia type for cataract surgery in a veteran population. Secondary objectives are to determine if patient age, and first or second eye surgery affect intra-operative pain control or are correlated with type of anesthesia modality. A retrospective study of 330 cataract surgeries performed by resident physicians between January and September 2012 at the Veterans Affairs Medical Center Tennessee Valley Healthcare System, Nashville and Murfreesboro Campuses was completed. Three hundred and thirty veteran patients were selected if their cataract surgery was performed between January and September 2012. Combined cases were excluded. The primary outcome evaluated was intra-operative analgesia. Secondary outcomes included history of post-traumatic-stress-disorder, anesthesia type, first or second eye, pain control, intra-operative heart rate and blood pressure, age, and case complexity. Data was analyzed using an unpaired two-sample Welch's t-test assuming unequal variance and Z test of comparison of proportions. Patients with post-traumatic-stress-disorder reported higher pain scores, had longer operative times, and were more likely to have received a retrobulbar block. Operative time was not associated with an increased pain score, irrespective of anesthesia type, when controlled for PTSD. Complex cases had longer operative times, more sedation, and higher pain scores. P < 0.05 was used consistently. Post-traumatic stress disorder and anxiety are more prevalent in the veteran population. Our data suggests that a history of post-traumatic-stress-disorder was correlated with higher pain scores, longer operative times, and with having received a retrobulbar block. Patients without a history of PTSD were more likely to have received topical anesthesia with or without sedation. The veteran population requires more sedation to allay anxiety and perceptions of discomfort, which may account for longer surgical times. The veteran population is a special population and it is important to investigate how PTSD in the veteran population affects intra-operative analgesia.

Variance estimation when using inverse probability of treatment weighting (IPTW) with survival analysis.

PubMed

Austin, Peter C

2016-12-30

Propensity score methods are used to reduce the effects of observed confounding when using observational data to estimate the effects of treatments or exposures. A popular method of using the propensity score is inverse probability of treatment weighting (IPTW). When using this method, a weight is calculated for each subject that is equal to the inverse of the probability of receiving the treatment that was actually received. These weights are then incorporated into the analyses to minimize the effects of observed confounding. Previous research has found that these methods result in unbiased estimation when estimating the effect of treatment on survival outcomes. However, conventional methods of variance estimation were shown to result in biased estimates of standard error. In this study, we conducted an extensive set of Monte Carlo simulations to examine different methods of variance estimation when using a weighted Cox proportional hazards model to estimate the effect of treatment. We considered three variance estimation methods: (i) a naïve model-based variance estimator; (ii) a robust sandwich-type variance estimator; and (iii) a bootstrap variance estimator. We considered estimation of both the average treatment effect and the average treatment effect in the treated. We found that the use of a bootstrap estimator resulted in approximately correct estimates of standard errors and confidence intervals with the correct coverage rates. The other estimators resulted in biased estimates of standard errors and confidence intervals with incorrect coverage rates. Our simulations were informed by a case study examining the effect of statin prescribing on mortality. © 2016 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd. © 2016 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd.

Genetic predisposition scores associate with muscular strength, size, and trainability.

PubMed

Thomaes, Tom; Thomis, Martine; Onkelinx, Steven; Goetschalckx, Kaatje; Fagard, Robert; Lambrechts, Diether; Vanhees, Luc

2013-08-01

The number of studies trying to identify genetic sequence variation related to muscular phenotypes has increased enormously. The aim of this study was to identify the role of a genetic predisposition score (GPS) based on earlier identified gene variants for different muscular endophenotypes to explain the individual differences in muscular fitness characteristics and the response to training in patients with coronary artery disease. Two hundred and sixty coronary artery disease patients followed a standard ambulatory, 3-month supervised training program for cardiac patients. Maximal knee extension strength (KES) and rectus femoris diameter were measured at baseline and after rehabilitation. Sixty-five single nucleotide polymorphisms (SNP) in 30 genes were selected based on genotype-phenotype association literature. Backward regression analysis revealed subsets of SNP associated with the different phenotypes. GPS were constructed for all sets of SNP by adding up the strength-increasing alleles. General linear models and multiple stepwise regression analysis were used to test the explained variance of the GPS in baseline and strength responses. Receiver operating characteristic curve analyses were performed to discriminate between high- and low-responder status. GPS were significantly associated with the rectus femoris diameter (P < 0.01) and its response (P < 0.0001), the isometric KES (P < 0.05) and its response (P < 0.01), the isokinetic KES at 60° · s (P < 0.05) and 180° · s (P < 0.001) and their responses to training (P < 0.0001), and the isokinetic KES endurance (P < 0.001) and its change after training (P < 0.0001). The GPS was shown as an independent determinant in baseline and response phenotypes with partial explained variance up to 23%. Receiver operating characteristic analysis showed a significant discriminating accuracy of the models, including the GPS for responses to training, with areas under the curve ranging from 0.62 to 0.85. GPS for muscular phenotypes showed to be associated with baseline KES, muscle diameter, and the response to training in cardiac rehabilitation patients.

Quantum mechanical expansion of variance of a particle in a weakly non-uniform electric and magnetic field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chan, Poh Kam; Kosaka, Wataru; Oikawa, Shun-ichi

We have solved the Heisenberg equation of motion for the time evolution of the position and momentum operators for a non-relativistic spinless charged particle in the presence of a weakly non-uniform electric and magnetic field. It is shown that the drift velocity operator obtained in this study agrees with the classical counterpart, and that, using the time dependent operators, the variances in position and momentum grow with time. The expansion rate of variance in position and momentum are dependent on the magnetic gradient scale length, however, independent of the electric gradient scale length. In the presence of a weakly non-uniformmore » electric and magnetic field, the theoretical expansion rates of variance expansion are in good agreement with the numerical analysis. It is analytically shown that the variance in position reaches the square of the interparticle separation, which is the characteristic time much shorter than the proton collision time of plasma fusion. After this time, the wavefunctions of the neighboring particles would overlap, as a result, the conventional classical analysis may lose its validity. The broad distribution of individual particle in space means that their Coulomb interactions with other particles become weaker than that expected in classical mechanics.« less

Adding a Parameter Increases the Variance of an Estimated Regression Function

ERIC Educational Resources Information Center

Withers, Christopher S.; Nadarajah, Saralees

2011-01-01

The linear regression model is one of the most popular models in statistics. It is also one of the simplest models in statistics. It has received applications in almost every area of science, engineering and medicine. In this article, the authors show that adding a predictor to a linear model increases the variance of the estimated regression…

Atmospheric Radiation Measurement program climate research facility operations quarterly report October 1 - December 31, 2008.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sisterson, D. L.

2009-01-15

Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, they calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month formore » the current year and (2) site and fiscal year (FY) dating back to 1998. The US Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1-(ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the first quarter of FY 2009 for the Southern Great Plains (SGP) site is 2,097.60 hours (0.95 x 2,208 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,987.20 hours (0.90 x 2,208), and for the Tropical Western Pacific (TWP) locale is 1,876.80 hours (0.85 x 2,208). The OPSMAX time for the ARM Mobile Facility (AMF) is not reported this quarter because the data have not yet been released from China to the DMF for processing. The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percentage of data in the Archive represents the average percentage of the time (24 hours per day, 92 days for this quarter) the instruments were operating this quarter. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for the period October 1-December 31, 2008, for the fixed sites. The AMF has been deployed to China, but the data have not yet been released. The first quarter comprises a total of 2,208 hours. The average exceeded their goal this quarter.« less

Atmospheric Radiation Measurement program climate research facility operations quarterly report January 1 - March 31, 2009.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sisterson, D. L.

2009-04-23

Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month formore » the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 - (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the second quarter of FY 2009 for the Southern Great Plains (SGP) site is 2,052.00 hours (0.95 x 2,160 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,944.00 hours (0.90 x 2,160), and for the Tropical Western Pacific (TWP) locale is 1,836.00 hours (0.85 x 2,160). The OPSMAX time for the ARM Mobile Facility (AMF) is not reported this quarter because not all of the metadata have been acquired that are used to generate this metric. The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percentage of data in the Archive represents the average percentage of the time (24 hours per day, 90 days for this quarter) the instruments were operating this quarter. Summary. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for the period January 1 - March 31, 2009, for the fixed sites. The AMF has completed its mission in China but not all of the data can be released to the public at the time of this report. The second quarter comprises a total of 2,160 hours. The average exceeded our goal this quarter.« less

An analysis of carrier phase jitter in an MPSK receiver utilizing map estimation. Ph.D. Thesis Semiannual Status Report, Jul. 1993 - Jan. 1994

NASA Technical Reports Server (NTRS)

Osborne, William P.

1994-01-01

The use of 8 and 16 PSK TCM to support satellite communications in an effort to achieve more bandwidth efficiency in a power-limited channel has been proposed. This project addresses the problem of carrier phase jitter in an M-PSK receiver utilizing the high SNR approximation to the maximum aposteriori estimation of carrier phase. In particular, numerical solutions to the 8 and 16 PSK self-noise and phase detector gain in the carrier tracking loop are presented. The effect of changing SNR on the loop noise bandwidth is also discussed. These data are then used to compute variance of phase error as a function of SNR. Simulation and hardware data are used to verify these calculations. The results show that there is a threshold in the variance of phase error versus SNR curves that is a strong function of SNR and a weak function of loop bandwidth. The M-PSK variance thresholds occur at SNR's in the range of practical interest for the use of 8 and 16-PSK TCM. This suggests that phase error variance is an important consideration in the design of these systems.

A class of multi-period semi-variance portfolio for petroleum exploration and development

NASA Astrophysics Data System (ADS)

Guo, Qiulin; Li, Jianzhong; Zou, Caineng; Guo, Yujuan; Yan, Wei

2012-10-01

Variance is substituted by semi-variance in Markowitz's portfolio selection model. For dynamic valuation on exploration and development projects, one period portfolio selection is extended to multi-period. In this article, a class of multi-period semi-variance exploration and development portfolio model is formulated originally. Besides, a hybrid genetic algorithm, which makes use of the position displacement strategy of the particle swarm optimiser as a mutation operation, is applied to solve the multi-period semi-variance model. For this class of portfolio model, numerical results show that the mode is effective and feasible.

Comparison of visual acuity of the patients on the first day after sub-Bowman keratomileusis or laser in situ keratomileusis.

PubMed

Zhao, Wei; Wu, Ting; Dong, Ze-Hong; Feng, Jie; Ren, Yu-Feng; Wang, Yu-Sheng

2016-01-01

To compare recovery of the visual acuity in patients one day after sub-Bowman keratomileusis (SBK) or laser in situ keratomileusis (LASIK). Data from 5923 eyes in 2968 patients that received LASIK (2755 eyes) or SBK (3168 eyes) were retrospectively analyzed. The eyes were divided into 4 groups according to preoperative spherical equivalent: between -12.00 to -9.00 D, extremely high myopia (n=396, including 192 and 204 in SBK and LASIK groups, respectively); -9.00 to -6.00 D, high myopia (n=1822, including 991 and 831 in SBK and LASIK groups, respectively), -6.00 to -3.00 D, moderate myopia (n=3071, including 1658 and 1413 in SBK and LASIK groups, respectively), and -3.00 to 0.00 D, low myopia (n=634, including 327 and 307 in SBK and LASIK groups, respectively). Uncorrected logMAR visual acuity values of patients were assessed under standard natural light. Analysis of variance was used for comparisons among different groups. Uncorrected visual acuity values were 0.0115±0.1051 and 0.0466±0.1477 at day 1 after operation for patients receiving SBK and LASIK, respectively (P<0.01); visual acuity values of 0.1854±0.1842, 0.0615±0.1326, -0.0033±0.0978, and -0.0164±0.0972 were obtained for patients in the extremely high, high, moderate, and low myopia groups, respectively (P<0.01). In addition, significant differences in visual acuity at day 1 after operation were found between patients receiving SBK and LASIK in each myopia subgroup. Compared with LASIK, SBK is safer and more effective, with faster recovery. Therefore, SBK is more likely to be accepted by patients than LASIK for better uncorrected visual acuity the day following operation.

Atmospheric Radiation Measurement program climate research facility operations quarterly report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sisterson, D. L.; Decision and Information Sciences

2006-09-06

Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and monthmore » for the current year and (2) site and fiscal year dating back to 1998. The U.S. Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1-(ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the third quarter for the Southern Great Plains (SGP) site is 2,074.80 hours (0.95 x 2,184 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,965.60 hours (0.90 x 2,184), and that for the Tropical Western Pacific (TWP) locale is 1,856.40 hours (0.85 x 2,184). The OPSMAX time for the ARM Mobile Facility (AMF) is 2,074.80 hours (0.95 x 2,184). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent of data in the Archive represents the average percent of the time (24 hours per day, 91 days for this quarter) the instruments were operating this quarter. Table 1 shows the accumulated maximum operation time (planned uptime), the actual hours of operation, and the variance (unplanned downtime) for the period April 1 through June 30, 2006, for the fixed and mobile sites. Although the AMF is currently up and running in Niamey, Niger, Africa, the AMF statistics are reported separately and not included in the aggregate average with the fixed sites. The third quarter comprises a total of 2,184 hours. For all fixed sites (especially the TWP locale) and the AMF, the actual data availability (and therefore actual hours of operation) exceeded the individual (and well as aggregate average of the fixed sites) operational goal for the third quarter of fiscal year (FY) 2006.« less

Waddell non-organic signs: new evidence suggests somatic amplification among outpatient chronic pain patients.

PubMed

Wygant, Dustin B; Arbisi, Paul A; Bianchini, Kevin J; Umlauf, Robert L

2017-04-01

Waddell et al. identified a set of eight non-organic signs in 1980. There has been controversy about their meaning, particularly with respect to their use as validity indicators. The current study examined the Waddell signs in relation to measures of somatic amplification or over-reporting in a sample of outpatient chronic pain patients. We examined the degree to which these signs were associated with measures of over-reporting. This study examined scores on the Waddell signs in relation to over-reporting indicators in an outpatient chronic pain sample. We examined 230 chronic pain patients treated at a multidisciplinary pain clinic. The majority of these patients presented with primary back or spinal injuries. The outcome measures used in the study were Waddell signs, Modified Somatic Perception Questionnaire, Pain Disability Index, and the Minnesota Multiphasic Personality Inventory-2 Restructured Form. We examined Waddell signs using multivariate analysis of variance (MANOVA) and analysis of variance (ANOVA), receiver operating characteristic analysis, classification accuracy, and relative risk ratios. Multivariate analysis of variance and ANOVA showed a significant association between Waddell signs and somatic amplification. Classification analyses showed increased odds of somatic amplification at a Waddell score of 2 or 3. Our results found significant evidence of an association between Waddell signs and somatic over-reporting. Elevated scores on the Waddell signs (particularly scores higher than 2 and 3) were associated with increased odds of exhibiting somatic over-reporting. Copyright © 2016 Elsevier Inc. All rights reserved.

An automatic frequency control loop using overlapping DFTs (Discrete Fourier Transforms)

NASA Technical Reports Server (NTRS)

Aguirre, S.

1988-01-01

An automatic frequency control (AFC) loop is introduced and analyzed in detail. The new scheme is a generalization of the well known Cross Product AFC loop that uses running overlapping discrete Fourier transforms (DFTs) to create a discriminator curve. Linear analysis is included and supported with computer simulations. The algorithm is tested in a low carrier to noise ratio (CNR) dynamic environment, and the probability of loss of lock is estimated via computer simulations. The algorithm discussed is a suboptimum tracking scheme with a larger frequency error variance compared to an optimum strategy, but offers simplicity of implementation and a very low operating threshold CNR. This technique can be applied during the carrier acquisition and re-acquisition process in the Advanced Receiver.

Application of fractal and grey level co-occurrence matrix analysis in evaluation of brain corpus callosum and cingulum architecture.

PubMed

Pantic, Igor; Dacic, Sanja; Brkic, Predrag; Lavrnja, Irena; Pantic, Senka; Jovanovic, Tomislav; Pekovic, Sanja

2014-10-01

This aim of this study was to assess the discriminatory value of fractal and grey level co-occurrence matrix (GLCM) analysis methods in standard microscopy analysis of two histologically similar brain white mass regions that have different nerve fiber orientation. A total of 160 digital micrographs of thionine-stained rat brain white mass were acquired using a Pro-MicroScan DEM-200 instrument. Eighty micrographs from the anterior corpus callosum and eighty from the anterior cingulum areas of the brain were analyzed. The micrographs were evaluated using the National Institutes of Health ImageJ software and its plugins. For each micrograph, seven parameters were calculated: angular second moment, inverse difference moment, GLCM contrast, GLCM correlation, GLCM variance, fractal dimension, and lacunarity. Using the Receiver operating characteristic analysis, the highest discriminatory value was determined for inverse difference moment (IDM) (area under the receiver operating characteristic (ROC) curve equaled 0.925, and for the criterion IDM≤0.610 the sensitivity and specificity were 82.5 and 87.5%, respectively). Most of the other parameters also showed good sensitivity and specificity. The results indicate that GLCM and fractal analysis methods, when applied together in brain histology analysis, are highly capable of discriminating white mass structures that have different axonal orientation.

Recollection is a continuous process: Evidence from plurality memory receiver operating characteristics.

PubMed

Slotnick, Scott D; Jeye, Brittany M; Dodson, Chad S

2016-01-01

Is recollection a continuous/graded process or a threshold/all-or-none process? Receiver operating characteristic (ROC) analysis can answer this question as the continuous model and the threshold model predict curved and linear recollection ROCs, respectively. As memory for plurality, an item's previous singular or plural form, is assumed to rely on recollection, the nature of recollection can be investigated by evaluating plurality memory ROCs. The present study consisted of four experiments. During encoding, words (singular or plural) or objects (single/singular or duplicate/plural) were presented. During retrieval, old items with the same plurality or different plurality were presented. For each item, participants made a confidence rating ranging from "very sure old", which was correct for same plurality items, to "very sure new", which was correct for different plurality items. Each plurality memory ROC was the proportion of same versus different plurality items classified as "old" (i.e., hits versus false alarms). Chi-squared analysis revealed that all of the plurality memory ROCs were adequately fit by the continuous unequal variance model, whereas none of the ROCs were adequately fit by the two-high threshold model. These plurality memory ROC results indicate recollection is a continuous process, which complements previous source memory and associative memory ROC findings.

Host nutrition alters the variance in parasite transmission potential

PubMed Central

Vale, Pedro F.; Choisy, Marc; Little, Tom J.

2013-01-01

The environmental conditions experienced by hosts are known to affect their mean parasite transmission potential. How different conditions may affect the variance of transmission potential has received less attention, but is an important question for disease management, especially if specific ecological contexts are more likely to foster a few extremely infectious hosts. Using the obligate-killing bacterium Pasteuria ramosa and its crustacean host Daphnia magna, we analysed how host nutrition affected the variance of individual parasite loads, and, therefore, transmission potential. Under low food, individual parasite loads showed similar mean and variance, following a Poisson distribution. By contrast, among well-nourished hosts, parasite loads were right-skewed and overdispersed, following a negative binomial distribution. Abundant food may, therefore, yield individuals causing potentially more transmission than the population average. Measuring both the mean and variance of individual parasite loads in controlled experimental infections may offer a useful way of revealing risk factors for potential highly infectious hosts. PMID:23407498

Host nutrition alters the variance in parasite transmission potential.

PubMed

Vale, Pedro F; Choisy, Marc; Little, Tom J

2013-04-23

The environmental conditions experienced by hosts are known to affect their mean parasite transmission potential. How different conditions may affect the variance of transmission potential has received less attention, but is an important question for disease management, especially if specific ecological contexts are more likely to foster a few extremely infectious hosts. Using the obligate-killing bacterium Pasteuria ramosa and its crustacean host Daphnia magna, we analysed how host nutrition affected the variance of individual parasite loads, and, therefore, transmission potential. Under low food, individual parasite loads showed similar mean and variance, following a Poisson distribution. By contrast, among well-nourished hosts, parasite loads were right-skewed and overdispersed, following a negative binomial distribution. Abundant food may, therefore, yield individuals causing potentially more transmission than the population average. Measuring both the mean and variance of individual parasite loads in controlled experimental infections may offer a useful way of revealing risk factors for potential highly infectious hosts.

Amplitude Scintillation due to Atmospheric Turbulence for the Deep Space Network Ka-Band Downlink

NASA Technical Reports Server (NTRS)

Ho, C.; Wheelon, A.

2004-01-01

Fast amplitude variations due to atmospheric scintillation are the main concerns for the Deep Space Network (DSN) Ka-band downlink under clear weather conditions. A theoretical study of the amplitude scintillation variances for a finite aperture antenna is presented. Amplitude variances for weak scattering scenarios are examined using turbulence theory to describe atmospheric irregularities. We first apply the Kolmogorov turbulent spectrum to a point receiver for three different turbulent profile models, especially for an exponential model varying with altitude. These analytic solutions then are extended to a receiver with a finite aperture antenna for the three profile models. Smoothing effects of antenna aperture are expressed by gain factors. A group of scaling factor relations is derived to show the dependences of amplitude variances on signal wavelength, antenna size, and elevation angle. Finally, we use these analytic solutions to estimate the scintillation intensity for a DSN Goldstone 34-m receiving station. We find that the (rms) amplitude fluctuation is 0.13 dB at 20-deg elevation angle for an exponential model, while the fluctuation is 0.05 dB at 90 deg. These results will aid us in telecommunication system design and signal-fading prediction. They also provide a theoretical basis for further comparison with other measurements at Ka-band.

Atmospheric Radiation Measurement program climate research facility operations quarterly report April 1 - June 30, 2007.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sisterson, D. L.

2007-07-26

Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and monthmore » for the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 - (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the third quarter of FY 2007 for the Southern Great Plains (SGP) site is 2,074.8 hours (0.95 x 2,184 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,965.6 hours (0.90 x 2,184), and that for the Tropical Western Pacific (TWP) locale is 1,856.4 hours (0.85 x 2,184). The OPSMAX time for the ARM Mobile Facility (AMF) is 2,074.8 hours (0.95 x 2,184). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent of data in the Archive represents the average percent of the time (24 hours per day, 91 days for this quarter) the instruments were operating this quarter. Table 1 shows the accumulated maximum operation time (planned uptime), the actual hours of operation, and the variance (unplanned downtime) for the period April 1 through June 30, 2007, for the fixed sites only. The AMF has been deployed to Germany and is operational this quarter. The third quarter comprises a total of 2,184 hours. Although the average exceeded our goal this quarter, there were cash flow issues resulting from Continuing Resolution early in the period that did not allow for timely instrument repairs that kept our statistics lower than past quarters at all sites. The low NSA numbers resulted from missing MFRSR data this spring that appears to be recoverable but not available at the Archive at the time of this report.« less

Atmospheric Radiation Measurement program climate research facilities quarterly report April 1 - June 30, 2009.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sisterson, D. L.

2009-07-14

Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near-real time. Raw and processed data are then sent approximately daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and monthmore » for the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 - (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the third quarter of FY 2009 for the Southern Great Plains (SGP) site is 2,074.80 hours (0.95 x 2,184 hours this quarter); for the North Slope Alaska (NSA) locale it is 1,965.60 hours (0.90 x 2,184); and for the Tropical Western Pacific (TWP) locale it is 1,856.40 hours (0.85 x 2,184). The ARM Mobile Facility (AMF) was officially operational May 1 in Graciosa Island, the Azores, Portugal, so the OPSMAX time this quarter is 1390.80 hours (0.95 x 1464). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percentage of data in the Archive represents the average percentage of the time (24 hours per day, 91 days for this quarter) the instruments were operating this quarter. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for April 1 - June 30, 2009, for the fixed sites. Because the AMF operates episodically, the AMF statistics are reported separately and are not included in the aggregate average with the fixed sites. The AMF statistics for this reporting period were not available at the time of this report. The third quarter comprises a total of 2,184 hours for the fixed sites. The average well exceeded our goal this quarter.« less

Managing risk and expected financial return from selective expansion of operating room capacity: mean-variance analysis of a hospital's portfolio of surgeons.

PubMed

Dexter, Franklin; Ledolter, Johannes

2003-07-01

Surgeons using the same amount of operating room (OR) time differ in their achieved hospital contribution margins (revenue minus variable costs) by >1000%. Thus, to improve the financial return from perioperative facilities, OR strategic decisions should selectively focus additional OR capacity and capital purchasing on a few surgeons or subspecialties. These decisions use estimates of each surgeon's and/or subspecialty's contribution margin per OR hour. The estimates are subject to uncertainty (e.g., from outliers). We account for the uncertainties by using mean-variance portfolio analysis (i.e., quadratic programming). This method characterizes the problem of selectively expanding OR capacity based on the expected financial return and risk of different portfolios of surgeons. The assessment reveals whether the choices, of which surgeons have their OR capacity expanded, are sensitive to the uncertainties in the surgeons' contribution margins per OR hour. Thus, mean-variance analysis reduces the chance of making strategic decisions based on spurious information. We also assess the financial benefit of using mean-variance portfolio analysis when the planned expansion of OR capacity is well diversified over at least several surgeons or subspecialties. Our results show that, in such circumstances, there may be little benefit from further changing the portfolio to reduce its financial risk. Surgeon and subspecialty specific hospital financial data are uncertain, a fact that should be taken into account when making decisions about expanding operating room capacity. We show that mean-variance portfolio analysis can incorporate this uncertainty, thereby guiding operating room management decision-making and reducing the chance of a strategic decision being made based on spurious information.

The Compass Paradigm for the Systematic Evaluation of U.S. Army Command and Control Systems Using Neural Network and Discrete Event Computer Simulation

DTIC Science & Technology

2005-11-01

interest has a large variance so that excessive run lengths are required. This naturally invokes the interest for searches for effective variance ...years since World War II the nature , organization, and mode of the operation of command organizations within the Army has remained virtually...Laboratory began a series of studies and projects focused on investigating the nature of military command and control (C2) operations. The questions

Gender differences in psychosocial predictors of texting while driving.

PubMed

Struckman-Johnson, Cindy; Gaster, Samuel; Struckman-Johnson, Dave; Johnson, Melissa; May-Shinagle, Gabby

2015-01-01

A sample of 158 male and 357 female college students at a midwestern university participated in an on-line study of psychosocial motives for texting while driving. Men and women did not differ in self-reported ratings of how often they texted while driving. However, more women sent texts of less than a sentence while more men sent texts of 1-5 sentences. More women than men said they would quit texting while driving due to police warnings, receiving information about texting dangers, being shown graphic pictures of texting accidents, and being in a car accident. A hierarchical regression for men's data revealed that lower levels of feeling distracted by texting while driving (20% of the variance), higher levels of cell phone dependence (11.5% of the variance), risky behavioral tendencies (6.5% of the variance) and impulsivity (2.3%) of the variance) were significantly associated with more texting while driving (total model variance=42%). A separate regression for women revealed that higher levels of cell phone dependence (10.4% of the variance), risky behavioral tendencies (9.9% of the variance), texting distractibility (6.2%), crash risk estimates (2.2% of the variance) and driving confidence (1.3% of the variance) were significantly associated with more texting while driving (total model variance=31%.) Friendship potential and need for intimacy were not related to men's or women's texting while driving. Implications of the results for gender-specific prevention strategies are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Bayesian semiparametric estimation of covariate-dependent ROC curves

PubMed Central

Rodríguez, Abel; Martínez, Julissa C.

2014-01-01

Receiver operating characteristic (ROC) curves are widely used to measure the discriminating power of medical tests and other classification procedures. In many practical applications, the performance of these procedures can depend on covariates such as age, naturally leading to a collection of curves associated with different covariate levels. This paper develops a Bayesian heteroscedastic semiparametric regression model and applies it to the estimation of covariate-dependent ROC curves. More specifically, our approach uses Gaussian process priors to model the conditional mean and conditional variance of the biomarker of interest for each of the populations under study. The model is illustrated through an application to the evaluation of prostate-specific antigen for the diagnosis of prostate cancer, which contrasts the performance of our model against alternative models. PMID:24174579

Management Accounting in School Food Service.

ERIC Educational Resources Information Center

Bryan, E. Lewis; Friedlob, G. Thomas

1982-01-01

Describes a model for establishing control of school food services through analysis of the aggregate variances of quantity, collection, and price, and of their separate components. The separable component variances are identified, measured, and compared monthly to help supervisors identify exactly where plans and operations vary. (Author/MLF)

Atmospheric Radiation Measurement program climate research facility operations quarterly report July 1 - Sep. 30, 2009.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sisterson, D. L.

2009-10-15

Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near-real time. Raw and processed data are then sent approximately daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and monthmore » for the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 - (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the fourth quarter of FY 2009 for the Southern Great Plains (SGP) site is 2,097.60 hours (0.95 ? 2,208 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,987.20 hours (0.90 ? 2,208) and for the Tropical Western Pacific (TWP) locale is 1,876.8 hours (0.85 ? 2,208). The ARM Mobile Facility (AMF) was officially operational May 1 in Graciosa Island, the Azores, Portugal, so the OPSMAX time this quarter is 2,097.60 hours (0.95 x 2,208). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive result from downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percentage of data in the Archive represents the average percentage of the time (24 hours per day, 92 days for this quarter) the instruments were operating this quarter. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for the period July 1 - September 30, 2009, for the fixed sites. Because the AMF operates episodically, the AMF statistics are reported separately and not included in the aggregate average with the fixed sites. The fourth quarter comprises a total of 2,208 hours for the fixed and mobile sites. The average of the fixed sites well exceeded our goal this quarter. The AMF data statistic requires explanation. Since the AMF radar data ingest software is being modified, the data are being stored in the DMF for data processing. Hence, the data are not at the Archive; they are anticipated to become available by the next report.« less

Effects of Prone Position and Positive End-Expiratory Pressure on Noninvasive Estimators of ICP: A Pilot Study.

PubMed

Robba, Chiara; Bragazzi, Nicola Luigi; Bertuccio, Alessandro; Cardim, Danilo; Donnelly, Joseph; Sekhon, Mypinder; Lavinio, Andrea; Duane, Derek; Burnstein, Rowan; Matta, Basil; Bacigaluppi, Susanna; Lattuada, Marco; Czosnyka, Marek

2017-07-01

Prone positioning and positive end-expiratory pressure can improve pulmonary gas exchange and respiratory mechanics. However, they may be associated with the development of intracranial hypertension. Intracranial pressure (ICP) can be noninvasively estimated from the sonographic measurement of the optic nerve sheath diameter (ONSD) and from the transcranial Doppler analysis of the pulsatility (ICPPI) and the diastolic component (ICPFVd) of the velocity waveform. The effect of the prone positioning and positive end-expiratory pressure on ONSD, ICPFVd, and ICPPI was assessed in a prospective study of 30 patients undergoing spine surgery. One-way repeated measures analysis of variance, fixed-effect multivariate regression models, and receiver operating characteristic analyses were used to analyze numerical data. The mean values of ONSD, ICPFVd, and ICPPI significantly increased after change from supine to prone position. Receiver operating characteristic analyses demonstrated that, among the noninvasive methods, the mean ONSD measure had the greatest area under the curve signifying it is the most effective in distinguishing a hypothetical change in ICP between supine and prone positioning (0.86±0.034 [0.79 to 0.92]). A cutoff of 0.43 cm was found to be a best separator of ONSD value between supine and prone with a specificity of 75.0 and a sensitivity of 86.7. Noninvasive ICP estimation may be useful in patients at risk of developing intracranial hypertension who require prone positioning.

The application of a multi-dimensional assessment approach to talent identification in Australian football.

PubMed

Woods, Carl T; Raynor, Annette J; Bruce, Lyndell; McDonald, Zane; Robertson, Sam

2016-07-01

This study investigated whether a multi-dimensional assessment could assist with talent identification in junior Australian football (AF). Participants were recruited from an elite under 18 (U18) AF competition and classified into two groups; talent identified (State U18 Academy representatives; n = 42; 17.6 ± 0.4 y) and non-talent identified (non-State U18 Academy representatives; n = 42; 17.4 ± 0.5 y). Both groups completed a multi-dimensional assessment, which consisted of physical (standing height, dynamic vertical jump height and 20 m multistage fitness test), technical (kicking and handballing tests) and perceptual-cognitive (video decision-making task) performance outcome tests. A multivariate analysis of variance tested the main effect of status on the test criterions, whilst a receiver operating characteristic curve assessed the discrimination provided from the full assessment. The talent identified players outperformed their non-talent identified peers in each test (P < 0.05). The receiver operating characteristic curve reflected near perfect discrimination (AUC = 95.4%), correctly classifying 95% and 86% of the talent identified and non-talent identified participants, respectively. When compared to single assessment approaches, this multi-dimensional assessment reflects a more comprehensive means of talent identification in AF. This study further highlights the importance of assessing multi-dimensional performance qualities when identifying talented team sports.

Developing the Scale for Quality of Life in Pediatric Oncology Patients Aged 13-18: Adolescent Form and Parent Form.

PubMed

Bektas, Murat; Akdeniz Kudubes, Aslı; Ugur, Ozlem; Vergin, Canan; Demirag, Bengü

2016-06-01

This study aimed to develop the Scale for Quality of Life in Pediatric Oncology Patients Aged 13-18: Adolescent Form and Parent Form. We used the child and parent information form, Visual Quality of Life Scale, and our own scale, the Scale for Quality of Life in Pediatric Oncology Patients Aged 13-18: Adolescent Form and Parent Form. We finalized the 35-item scale to determine the items, received opinions from 14 specialists on the scale, and pilot-tested the scale in 25 children and their parents. We used Pearson correlation analysis, Cronbach α coefficient, factor analysis and receiver operating characteristics analysis to analyze the data. The total Cronbach α of the parent form was .97, the total factor load was .60-.97 and the total variance was 80.4%. The cutoff point of the parent form was 85.50. The total Cronbach α of the adolescent form was .98, the total factor load was .62-.96, and the total variance explained was 83.4%. The cutoff point of the adolescent form was 75.50. As a result of the parent form factor analysis, we determined the Kaiser-Meyer-Olkin coefficient as .83, the Barlett test χ(2) as 12,615.92; the factor coefficients of all items of the parent form ranged from .63 to .98. The factor coefficients of all items of the adolescent form ranged from .34 to .99. As a result of the adolescent form factor analysis, we determined the KMO as .79, and the Barlett test χ(2) as 13,970.62. Conclusively, we found that the adolescent form and the parent form were valid and reliable in assessing the children's quality of life. Copyright © 2016. Published by Elsevier B.V.

The Effects of Laser Phase Noise on Laser Radar Performance

DTIC Science & Technology

1992-12-01

Laboratory 5. Figure 3 shows Allan variance plots of the above ultrastable C02 laser which has an open Fabry - Perot cavity 5. The open and solid circles...the same measurement time -r) by more than 10 dB. Therefore, the root Allan variance for the Fabry - Perot cavity ultrastable C02 laser can be...variance so that the SSB phase noise for the Fabry - Perot cavity ultrastable CO 2 laser is about 20 dB (because of the squaring operation) below that of the

Value of MR histogram analyses for prediction of microvascular invasion of hepatocellular carcinoma.

PubMed

Huang, Ya-Qin; Liang, He-Yue; Yang, Zhao-Xia; Ding, Ying; Zeng, Meng-Su; Rao, Sheng-Xiang

2016-06-01

The objective is to explore the value of preoperative magnetic resonance (MR) histogram analyses in predicting microvascular invasion (MVI) of hepatocellular carcinoma (HCC).Fifty-one patients with histologically confirmed HCC who underwent diffusion-weighted and contrast-enhanced MR imaging were included. Histogram analyses were performed and mean, variance, skewness, kurtosis, 1th, 10th, 50th, 90th, and 99th percentiles were derived. Quantitative histogram parameters were compared between HCCs with and without MVI. Receiver operating characteristics (ROC) analyses were generated to compare the diagnostic performance of tumor size, histogram analyses of apparent diffusion coefficient (ADC) maps, and MR enhancement.The mean, 1th, 10th, and 50th percentiles of ADC maps, and the mean, variance. 1th, 10th, 50th, 90th, and 99th percentiles of the portal venous phase (PVP) images were significantly different between the groups with and without MVI (P <0.05), with area under the ROC curves (AUCs) of 0.66 to 0.74 for ADC and 0.76 to 0.88 for PVP. The largest AUC of PVP (1th percentile) showed significantly higher accuracy compared with that of arterial phase (AP) or tumor size (P <0.001).MR histogram analyses-in particular for 1th percentile for PVP images-held promise for prediction of MVI of HCC.

Handling nonresponse in surveys: analytic corrections compared with converting nonresponders.

PubMed

Jenkins, Paul; Earle-Richardson, Giulia; Burdick, Patrick; May, John

2008-02-01

A large health survey was combined with a simulation study to contrast the reduction in bias achieved by double sampling versus two weighting methods based on propensity scores. The survey used a census of one New York county and double sampling in six others. Propensity scores were modeled as a logistic function of demographic variables and were used in conjunction with a random uniform variate to simulate response in the census. These data were used to estimate the prevalence of chronic disease in a population whose parameters were defined as values from the census. Significant (p < 0.0001) predictors in the logistic function included multiple (vs. single) occupancy (odds ratio (OR) = 1.3), bank card ownership (OR = 2.1), gender (OR = 1.5), home ownership (OR = 1.3), head of household's age (OR = 1.4), and income >$18,000 (OR = 0.8). The model likelihood ratio chi-square was significant (p < 0.0001), with the area under the receiver operating characteristic curve = 0.59. Double-sampling estimates were marginally closer to population values than those from either weighting method. However, the variance was also greater (p < 0.01). The reduction in bias for point estimation from double sampling may be more than offset by the increased variance associated with this method.

Inverse probability weighting estimation of the volume under the ROC surface in the presence of verification bias.

PubMed

Zhang, Ying; Alonzo, Todd A

2016-11-01

In diagnostic medicine, the volume under the receiver operating characteristic (ROC) surface (VUS) is a commonly used index to quantify the ability of a continuous diagnostic test to discriminate between three disease states. In practice, verification of the true disease status may be performed only for a subset of subjects under study since the verification procedure is invasive, risky, or expensive. The selection for disease examination might depend on the results of the diagnostic test and other clinical characteristics of the patients, which in turn can cause bias in estimates of the VUS. This bias is referred to as verification bias. Existing verification bias correction in three-way ROC analysis focuses on ordinal tests. We propose verification bias-correction methods to construct ROC surface and estimate the VUS for a continuous diagnostic test, based on inverse probability weighting. By applying U-statistics theory, we develop asymptotic properties for the estimator. A Jackknife estimator of variance is also derived. Extensive simulation studies are performed to evaluate the performance of the new estimators in terms of bias correction and variance. The proposed methods are used to assess the ability of a biomarker to accurately identify stages of Alzheimer's disease. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Auditory brainstem responses to stop consonants predict literacy.

PubMed

Neef, Nicole E; Schaadt, Gesa; Friederici, Angela D

2017-03-01

Precise temporal coding of speech plays a pivotal role in sound processing throughout the central auditory system, which, in turn, influences literacy acquisition. The current study tests whether an electrophysiological measure of this precision predicts literacy skills. Complex auditory brainstem responses were analysed from 62 native German-speaking children aged 11-13years. We employed the cross-phaseogram approach to compute the quality of the electrophysiological stimulus contrast [da] and [ba]. Phase shifts were expected to vary with literacy. Receiver operating curves demonstrated a feasible sensitivity and specificity of the electrophysiological measure. A multiple regression analysis resulted in a significant prediction of literacy by delta cross-phase as well as phonological awareness. A further commonality analysis separated a unique variance that was explained by the physiological measure, from a unique variance that was explained by the behavioral measure, and common effects of both. Despite multicollinearities between literacy, phonological awareness, and subcortical differentiation of stop consonants, a combined assessment of behavior and physiology strongly increases the ability to predict literacy skills. The strong link between the neurophysiological signature of sound encoding and literacy outcome suggests that the delta cross-phase could indicate the risk of dyslexia and thereby complement subjective psychometric measures for early diagnoses. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Comparison of visual acuity of the patients on the first day after sub-Bowman keratomileusis or laser in situ keratomileusis

PubMed Central

Zhao, Wei; Wu, Ting; Dong, Ze-Hong; Feng, Jie; Ren, Yu-Feng; Wang, Yu-Sheng

2016-01-01

AIM To compare recovery of the visual acuity in patients one day after sub-Bowman keratomileusis (SBK) or laser in situ keratomileusis (LASIK). METHODS Data from 5923 eyes in 2968 patients that received LASIK (2755 eyes) or SBK (3168 eyes) were retrospectively analyzed. The eyes were divided into 4 groups according to preoperative spherical equivalent: between -12.00 to -9.00 D, extremely high myopia (n=396, including 192 and 204 in SBK and LASIK groups, respectively); -9.00 to -6.00 D, high myopia (n=1822, including 991 and 831 in SBK and LASIK groups, respectively), -6.00 to -3.00 D, moderate myopia (n=3071, including 1658 and 1413 in SBK and LASIK groups, respectively), and -3.00 to 0.00 D, low myopia (n=634, including 327 and 307 in SBK and LASIK groups, respectively). Uncorrected logMAR visual acuity values of patients were assessed under standard natural light. Analysis of variance was used for comparisons among different groups. RESULTS Uncorrected visual acuity values were 0.0115±0.1051 and 0.0466±0.1477 at day 1 after operation for patients receiving SBK and LASIK, respectively (P<0.01); visual acuity values of 0.1854±0.1842, 0.0615±0.1326, -0.0033±0.0978, and -0.0164±0.0972 were obtained for patients in the extremely high, high, moderate, and low myopia groups, respectively (P<0.01). In addition, significant differences in visual acuity at day 1 after operation were found between patients receiving SBK and LASIK in each myopia subgroup. CONCLUSION Compared with LASIK, SBK is safer and more effective, with faster recovery. Therefore, SBK is more likely to be accepted by patients than LASIK for better uncorrected visual acuity the day following operation. PMID:27158619

Using the Beck Anxiety Inventory among South Africans Living with HIV: Exploratory and Higher Order Factor Analyses

ERIC Educational Resources Information Center

Kagee, Ashraf; Coetzee, Bronwyne; Saal, Wylene; Nel, Adriaan

2015-01-01

We administered the Beck Anxiety Inventory (BAI) to 101 adults receiving HIV treatment. Exploratory factor analysis yielded a single anxiety factor that accounted for 68.7% of the variance in the data. A single score may be used to indicate the overall level of anxiety of individuals receiving HIV treatment in South Africa.

Teamwork and error in the operating room: analysis of skills and roles.

PubMed

Catchpole, K; Mishra, A; Handa, A; McCulloch, P

2008-04-01

To analyze the effects of surgical, anesthetic, and nursing teamwork skills on technical outcomes. The value of team skills in reducing adverse events in the operating room is presently receiving considerable attention. Current work has not yet identified in detail how the teamwork and communication skills of surgeons, anesthetists, and nurses affect the course of an operation. Twenty-six laparoscopic cholecystectomies and 22 carotid endarterectomies were studied using direct observation methods. For each operation, teams' skills were scored for the whole team, and for nursing, surgical, and anesthetic subteams on 4 dimensions (leadership and management [LM]; teamwork and cooperation; problem solving and decision making; and situation awareness). Operating time, errors in surgical technique, and other procedural problems and errors were measured as outcome parameters for each operation. The relationships between teamwork scores and these outcome parameters within each operation were examined using analysis of variance and linear regression. Surgical (F(2,42) = 3.32, P = 0.046) and anesthetic (F(2,42) = 3.26, P = 0.048) LM had significant but opposite relationships with operating time in each operation: operating time increased significantly with higher anesthetic but decreased with higher surgical LM scores. Errors in surgical technique had a strong association with surgical situation awareness (F(2,42) = 7.93, P < 0.001) in each operation. Other procedural problems and errors were related to the intraoperative LM skills of the nurses (F(5,1) = 3.96, P = 0.027). Detailed analysis of team interactions and dimensions is feasible and valuable, yielding important insights into relationships between nontechnical skills, technical performance, and operative duration. These results support the concept that interventions designed to improve teamwork and communication may have beneficial effects on technical performance and patient outcome.

Dual-process theory and signal-detection theory of recognition memory.

PubMed

Wixted, John T

2007-01-01

Two influential models of recognition memory, the unequal-variance signal-detection model and a dual-process threshold/detection model, accurately describe the receiver operating characteristic, but only the latter model can provide estimates of recollection and familiarity. Such estimates often accord with those provided by the remember-know procedure, and both methods are now widely used in the neuroscience literature to identify the brain correlates of recollection and familiarity. However, in recent years, a substantial literature has accumulated directly contrasting the signal-detection model against the threshold/detection model, and that literature is almost unanimous in its endorsement of signal-detection theory. A dual-process version of signal-detection theory implies that individual recognition decisions are not process pure, and it suggests new ways to investigate the brain correlates of recognition memory. ((c) 2007 APA, all rights reserved).

Dual-process models of associative recognition in young and older adults: evidence from receiver operating characteristics.

PubMed

Healy, Michael R; Light, Leah L; Chung, Christie

2005-07-01

In 3 experiments, young and older adults studied lists of unrelated word pairs and were given confidence-rated item and associative recognition tests. Several different models of recognition were fit to the confidence-rating data using techniques described by S. Macho (2002, 2004). Concordant with previous findings, item recognition data were best fit by an unequal-variance signal detection theory model for both young and older adults. For both age groups, associative recognition performance was best explained by models incorporating both recollection and familiarity components. Examination of parameter estimates supported the conclusion that recollection is reduced in old age, but inferences about age differences in familiarity were highly model dependent. Implications for dual-process models of memory in old age are discussed. ((c) 2005 APA, all rights reserved).

Detection of nuclear resonance signals: modification of the receiver operating characteristics using feedback.

PubMed

Blauch, A J; Schiano, J L; Ginsberg, M D

2000-06-01

The performance of a nuclear resonance detection system can be quantified using binary detection theory. Within this framework, signal averaging increases the probability of a correct detection and decreases the probability of a false alarm by reducing the variance of the noise in the average signal. In conjunction with signal averaging, we propose another method based on feedback control concepts that further improves detection performance. By maximizing the nuclear resonance signal amplitude, feedback raises the probability of correct detection. Furthermore, information generated by the feedback algorithm can be used to reduce the probability of false alarm. We discuss the advantages afforded by feedback that cannot be obtained using signal averaging. As an example, we show how this method is applicable to the detection of explosives using nuclear quadrupole resonance. Copyright 2000 Academic Press.

Development of a Composite Measure of State-Level Malpractice Environment

PubMed Central

Chung, Jeanette W; Sohn, Min-Woong; Merkow, Ryan P; Oh, Elissa H; Minami, Christina; Black, Bernard S; Bilimoria, Karl Y

2014-01-01

Objective To develop a composite measure of state-level malpractice environment. Data Sources Public use data from the National Practitioner Data Bank, Medical Liability Monitor, the National Conference of State Legislatures, and the American Bar Association. Study Design Principal component analysis of state-level indicators (paid claims rate, malpractice premiums, lawyers per capita, average award size, and malpractice laws), with indirect validation of the composite using receiver-operating characteristic curves to determine how accurately the composite could identify states with high-tort activity and costs. Principal Findings A single composite accounted for over 73 percent of total variance in the seven indicators and demonstrated reasonable criterion validity. Conclusion An empirical composite measure of state-level malpractice risk may offer advantages over single indicators in measuring overall risk and may facilitate cross-state comparisons of malpractice environments. PMID:24117397

Combining Ratio Estimation for Low Density Parity Check (LDPC) Coding

NASA Technical Reports Server (NTRS)

Mahmoud, Saad; Hi, Jianjun

2012-01-01

The Low Density Parity Check (LDPC) Code decoding algorithm make use of a scaled receive signal derived from maximizing the log-likelihood ratio of the received signal. The scaling factor (often called the combining ratio) in an AWGN channel is a ratio between signal amplitude and noise variance. Accurately estimating this ratio has shown as much as 0.6 dB decoding performance gain. This presentation briefly describes three methods for estimating the combining ratio: a Pilot-Guided estimation method, a Blind estimation method, and a Simulation-Based Look-Up table. The Pilot Guided Estimation method has shown that the maximum likelihood estimates of signal amplitude is the mean inner product of the received sequence and the known sequence, the attached synchronization marker (ASM) , and signal variance is the difference of the mean of the squared received sequence and the square of the signal amplitude. This method has the advantage of simplicity at the expense of latency since several frames worth of ASMs. The Blind estimation method s maximum likelihood estimator is the average of the product of the received signal with the hyperbolic tangent of the product combining ratio and the received signal. The root of this equation can be determined by an iterative binary search between 0 and 1 after normalizing the received sequence. This method has the benefit of requiring one frame of data to estimate the combining ratio which is good for faster changing channels compared to the previous method, however it is computationally expensive. The final method uses a look-up table based on prior simulated results to determine signal amplitude and noise variance. In this method the received mean signal strength is controlled to a constant soft decision value. The magnitude of the deviation is averaged over a predetermined number of samples. This value is referenced in a look up table to determine the combining ratio that prior simulation associated with the average magnitude of the deviation. This method is more complicated than the Pilot-Guided Method due to the gain control circuitry, but does not have the real-time computation complexity of the Blind Estimation method. Each of these methods can be used to provide an accurate estimation of the combining ratio, and the final selection of the estimation method depends on other design constraints.

Novel low-cost millimeter-wave system for road surface characterization

NASA Astrophysics Data System (ADS)

Busuioc, Dan; Anstey, Kyle; Rappaport, Carey; Birken, Ralf; Doughty, Jeffrey; Wang, Ming

2011-04-01

A novel low-cost low-complexity design based on Radar technology operating at millimeter wave is presented for the characterization of road surface conditions in real-time. At frequencies of 24-77 GHz the wavelength is long enough to obtain slight penetration in the top 1-2" of asphalt or concrete surface, but is also short enough to resolve details such as crack or pothole depth/etc. The Radar system operates by continuously outputting radiation and sampling the roadway-reflected radiation through a receiver-downconverter-sampler system. In initial laboratory testing, the received signal strength was observed to obey the inverse distance 1/R2 relationship. The received signal is further dependent on the incidence angle between the plane of the sensor and the plane of the roadway. One observation from this is the need of auxiliary sensors for determining the distance above the road surface as well as providing incident angle data. The sensor was further mounted on a movable cart used to measure the reflected signal on a variety of road surfaces (smooth, rough, surface defects, and environment factors such as various levels of moisture). By comparing measurements of the material after soaking to measurements in the dry state, there is substantial differentiation in measurements, which indicates the ability to measure the porosity of various materials. Lastly the sensor bandwidth provides the capability to measure surface roughness illustrated in the standard deviation of measurement data. On a macroscopic level, the aggregate in a roadway acts as a series of random scatterers and rough roadways or roadways with surface voids show a large variance between measurements of nearby points.

Impact of Operative and Postoperative Factors on Neurodevelopmental Outcomes After Cardiac Operations.

PubMed

2016-09-01

Neurodevelopmental disability is common after operations for congenital heart defects. We previously showed that patient and preoperative factors, center, and calendar year of birth explained less than 30% of the variance for the Psychomotor Development Index (PDI) and the Mental Development Index (MDI) of the Bayley Scales of Infant Development-Second Edition. Here we investigate how much additional variance in PDI and MDI is contributed by operative variables and postoperative events. We analyzed neurodevelopmental outcomes after operations with cardiopulmonary bypass at age 9 months or younger between 1996 and 2009. We used linear regression to investigate the effect of operative factors (age, weight, and cardiopulmonary bypass variables) and postoperative events on neurodevelopmental outcomes, adjusting for center, type of congenital heart defect, year of birth, and preoperative factors. We analyzed 1,770 children from 22 institutions with neurodevelopmental testing at age 13.3 months (range, 6 to 30 months). Among operative factors, longer total support time was associated with lower PDI and MDI (p < 0.05). When postoperative events were added, use of either extracorporeal membrane oxygenation or ventricular assist device support, and longer postoperative length of stay were associated with lower PDI and MDI (p < 0.05). Longer total support time was not a significant predictor in these models. After adjusting for patient, preoperative, intraoperative, and postoperative factors, measured intraoperative and postoperative factors accounted for 5% of the variances in PDI and MDI. Operative factors may be less important than innate patient and preoperative factors and postoperative events in predicting early neurodevelopmental outcomes after cardiac operations in infants. Neurodevelopmental outcomes improved over calendar time when adjusted for patient and medical variables. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Predicting the Cost per Flying Hour for the F-16 Using Programmatic and Operational Variables

DTIC Science & Technology

2005-06-01

constant variance assumption is accomplished using the Breusch - Pagan test . This is accomplished and the results are listed in Table 12. Figures 19...and 20 follow and add to the discussion by plotting the residuals by predicted for both models. 52 Table 12: Breusch - Pagan Constant Variance Test ...Model A 13844455 6.97E+11 5 74 9.96 0.0764 Model B 74954796 8.69E+12 5 151 17.63 0.00344 Breusch - Pagan Test for Constant Variance -1000 -500 0 500

Within-patient temporal variance in MELD score and impact on survival prediction after TIPS creation.

PubMed

Gaba, Ron C; Shah, Kruti D; Couture, Patrick M; Parvinian, Ahmad; Minocha, Jeet; Knuttinen, M Grace; Bui, James T

2013-01-01

To assess within-patient temporal variability in Model for End Stage Liver Disease (MELD) scores and impact on outcome prognostication after transjugular intrahepatic portosystemic shunt (TIPS) creation. In this single institution retrospective study, MELD score was calculated in 68 patients (M:F = 42:26, mean age 55 years) at 4 pre-procedure time points (1, 2-6, 7-14, and 15-35 days) before TIPS creation. Medical record review was used to identify 30- and 90-day clinical outcomes. Within-patient variability in pre-procedure MELD scores was assessed using repeated measures analysis of variance, and the ability of MELD scores at different time points to predict post-TIPS mortality was evaluated by comparing area under receiver operating characteristic (AUROC) curves. TIPS were successfully created for ascites (n = 30), variceal hemorrhage (n = 29), hepatic hydrothorax (n = 8), and portal vein thrombosis (n = 1). Pre-TIPS MELD scores showed significant (P = 0.032) within-subject variance that approached ± 18.5%. Higher MELD scores demonstrated greater variability in sequential scores as compared to lower MELD scores. Overall 30- and 90-day patient mortality was 22% (15/67) and 38% (24/64). AUROC curves showed that most recent MELD scores performed on the day of TIPS had superior predictive capacity for 30- (0.876, P = 0.037) and 90-day (0.805 P = 0.020) mortality compared to MELD scores performed 2-6 or 7-14 days prior. In conclusion, MELD scores show within-patient variability over time, and scores calculated on the day of TIPS most accurately predict risk and should be used for patient selection and counseling.

Wavelets analysis for differentiating solid, non-macroscopic fat containing, enhancing renal masses: a pilot study

NASA Astrophysics Data System (ADS)

Varghese, Bino; Hwang, Darryl; Mohamed, Passant; Cen, Steven; Deng, Christopher; Chang, Michael; Duddalwar, Vinay

2017-11-01

Purpose: To evaluate potential use of wavelets analysis in discriminating benign and malignant renal masses (RM) Materials and Methods: Regions of interest of the whole lesion were manually segmented and co-registered from multiphase CT acquisitions of 144 patients (98 malignant RM: renal cell carcinoma (RCC) and 46 benign RM: oncocytoma, lipid-poor angiomyolipoma). Here, the Haar wavelet was used to analyze the grayscale images of the largest segmented tumor in the axial direction. Six metrics (energy, entropy, homogeneity, contrast, standard deviation (SD) and variance) derived from 3-levels of image decomposition in 3 directions (horizontal, vertical and diagonal) respectively, were used to quantify tumor texture. Independent t-test or Wilcoxon rank sum test depending on data normality were used as exploratory univariate analysis. Stepwise logistic regression and receiver operator characteristics (ROC) curve analysis were used to select predictors and assess prediction accuracy, respectively. Results: Consistently, 5 out of 6 wavelet-based texture measures (except homogeneity) were higher for malignant tumors compared to benign, when accounting for individual texture direction. Homogeneity was consistently lower in malignant than benign tumors irrespective of direction. SD and variance measured in the diagonal direction on the corticomedullary phase showed significant (p<0.05) difference between benign versus malignant tumors. The multivariate model with variance (3 directions) and SD (vertical direction) extracted from the excretory and pre-contrast phase, respectively showed an area under the ROC curve (AUC) of 0.78 (p < 0.05) in discriminating malignant from benign. Conclusion: Wavelet analysis is a valuable texture evaluation tool to add to a radiomics platforms geared at reliably characterizing and stratifying renal masses.

Interpreting the concordance statistic of a logistic regression model: relation to the variance and odds ratio of a continuous explanatory variable.

PubMed

Austin, Peter C; Steyerberg, Ewout W

2012-06-20

When outcomes are binary, the c-statistic (equivalent to the area under the Receiver Operating Characteristic curve) is a standard measure of the predictive accuracy of a logistic regression model. An analytical expression was derived under the assumption that a continuous explanatory variable follows a normal distribution in those with and without the condition. We then conducted an extensive set of Monte Carlo simulations to examine whether the expressions derived under the assumption of binormality allowed for accurate prediction of the empirical c-statistic when the explanatory variable followed a normal distribution in the combined sample of those with and without the condition. We also examine the accuracy of the predicted c-statistic when the explanatory variable followed a gamma, log-normal or uniform distribution in combined sample of those with and without the condition. Under the assumption of binormality with equality of variances, the c-statistic follows a standard normal cumulative distribution function with dependence on the product of the standard deviation of the normal components (reflecting more heterogeneity) and the log-odds ratio (reflecting larger effects). Under the assumption of binormality with unequal variances, the c-statistic follows a standard normal cumulative distribution function with dependence on the standardized difference of the explanatory variable in those with and without the condition. In our Monte Carlo simulations, we found that these expressions allowed for reasonably accurate prediction of the empirical c-statistic when the distribution of the explanatory variable was normal, gamma, log-normal, and uniform in the entire sample of those with and without the condition. The discriminative ability of a continuous explanatory variable cannot be judged by its odds ratio alone, but always needs to be considered in relation to the heterogeneity of the population.

Swarm based mean-variance mapping optimization (MVMOS) for solving economic dispatch

NASA Astrophysics Data System (ADS)

Khoa, T. H.; Vasant, P. M.; Singh, M. S. Balbir; Dieu, V. N.

2014-10-01

The economic dispatch (ED) is an essential optimization task in the power generation system. It is defined as the process of allocating the real power output of generation units to meet required load demand so as their total operating cost is minimized while satisfying all physical and operational constraints. This paper introduces a novel optimization which named as Swarm based Mean-variance mapping optimization (MVMOS). The technique is the extension of the original single particle mean-variance mapping optimization (MVMO). Its features make it potentially attractive algorithm for solving optimization problems. The proposed method is implemented for three test power systems, including 3, 13 and 20 thermal generation units with quadratic cost function and the obtained results are compared with many other methods available in the literature. Test results have indicated that the proposed method can efficiently implement for solving economic dispatch.

The Quantum Phase-Dynamical Properties of the Squeezed Vacuum State Intensity-Couple Interacting with the Atom

NASA Technical Reports Server (NTRS)

Fan, An-Fu; Sun, Nian-Chun; Zhou, Xin

1996-01-01

The Phase-dynamical properties of the squeezed vacuum state intensity-couple interacting with the two-level atom in an ideal cavity are studied using the Hermitian phase operator formalism. Exact general expressions for the phase distribution and the associated expectation value and variance of the phase operator have been derived. we have also obtained the analytic results of the phase variance for two special cases-weakly and strongly squeezed vacuum. The results calculated numerically show that squeezing has a significant effect on the phase properties of squeezed vacuum.

Peripapillary nerve fiber layer thickness measurement reproducibility using optical coherence tomography.

PubMed

Villain, Max A; Greenfield, David S

2003-01-01

To assess reproducibility of quadrantic and clock hour sectors of retinal nerve fiber layer thickness in normal eyes using optical coherence tomography. Normal eyes of healthy volunteers meeting eligibility criteria were imaged by two inexperienced operators. Six 360 degrees circular scans with a diameter of 3.4 mm centered on the optic disc were obtained during each scanning session, and a baseline image was formed using 3 high-quality images defined by the software. Images were obtained on three different days within a 4-week period. Variance and coefficient of variation (CV) were calculated for quadrantic and retinal nerve fiber layer clock hour sectors obtained from the baseline image. Five normal eyes were scanned. Intraoperator reproducibility was high. The mean (+/- SD) CV for total retinal nerve fiber layer thickness was 5.3 +/- 3.82% and 4.33 +/- 3.7% for operators 1 and 2, respectively. Interoperator reproducibility was good with statistically similar variance for all quadrantic and clock hour retinal nerve fiber layer parameters (P = .42 to .99). The nasal retinal nerve fiber layer was the most variable sector for both operators (mean CV: 10.42% and 7.83% for operators 1 and 2, respectively). Differences in mean total, nasal, temporal, and superior retinal nerve fiber layer thickness were not statistically significant between operators for all eyes; however, for inferior retinal nerve fiber layer thickness, there was a significant (P = .0007) difference between operators in one eye. Peripapillary retinal nerve fiber layer thickness assessments using optical coherence tomography have good intraoperator and interoperator reproducibility. Inexperienced operators can generate useful measurement data with acceptable levels of variance.

Eigentumors for prediction of treatment failure in patients with early-stage breast cancer using dynamic contrast-enhanced MRI: a feasibility study

NASA Astrophysics Data System (ADS)

Chan, H. M.; van der Velden, B. H. M.; E Loo, C.; Gilhuijs, K. G. A.

2017-08-01

We present a radiomics model to discriminate between patients at low risk and those at high risk of treatment failure at long-term follow-up based on eigentumors: principal components computed from volumes encompassing tumors in washin and washout images of pre-treatment dynamic contrast-enhanced (DCE-) MR images. Eigentumors were computed from the images of 563 patients from the MARGINS study. Subsequently, a least absolute shrinkage selection operator (LASSO) selected candidates from the components that contained 90% of the variance of the data. The model for prediction of survival after treatment (median follow-up time 86 months) was based on logistic regression. Receiver operating characteristic (ROC) analysis was applied and area-under-the-curve (AUC) values were computed as measures of training and cross-validated performances. The discriminating potential of the model was confirmed using Kaplan-Meier survival curves and log-rank tests. From the 322 principal components that explained 90% of the variance of the data, the LASSO selected 28 components. The ROC curves of the model yielded AUC values of 0.88, 0.77 and 0.73, for the training, leave-one-out cross-validated and bootstrapped performances, respectively. The bootstrapped Kaplan-Meier survival curves confirmed significant separation for all tumors (P  <  0.0001). Survival analysis on immunohistochemical subgroups shows significant separation for the estrogen-receptor subtype tumors (P  <  0.0001) and the triple-negative subtype tumors (P  =  0.0039), but not for tumors of the HER2 subtype (P  =  0.41). The results of this retrospective study show the potential of early-stage pre-treatment eigentumors for use in prediction of treatment failure of breast cancer.

SU-E-T-56: A Novel Approach to Computing Expected Value and Variance of Point Dose From Non-Gated Radiotherapy Delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, S; Zhu, X; Zhang, M

Purpose: Randomness in patient internal organ motion phase at the beginning of non-gated radiotherapy delivery may introduce uncertainty to dose received by the patient. Concerns of this dose deviation from the planned one has motivated many researchers to study this phenomenon although unified theoretical framework for computing it is still missing. This study was conducted to develop such framework for analyzing the effect. Methods: Two reasonable assumptions were made: a) patient internal organ motion is stationary and periodic; b) no special arrangement is made to start a non -gated radiotherapy delivery at any specific phase of patient internal organ motion.more » A statistical ensemble was formed consisting of patient’s non-gated radiotherapy deliveries at all equally possible initial organ motion phases. To characterize the patient received dose, statistical ensemble average method is employed to derive formulae for two variables: expected value and variance of dose received by a patient internal point from a non-gated radiotherapy delivery. Fourier Series was utilized to facilitate our analysis. Results: According to our formulae, the two variables can be computed from non-gated radiotherapy generated dose rate time sequences at the point’s corresponding locations on fixed phase 3D CT images sampled evenly in time over one patient internal organ motion period. The expected value of point dose is simply the average of the doses to the point’s corresponding locations on the fixed phase CT images. The variance can be determined by time integration in terms of Fourier Series coefficients of the dose rate time sequences on the same fixed phase 3D CT images. Conclusion: Given a non-gated radiotherapy delivery plan and patient’s 4D CT study, our novel approach can predict the expected value and variance of patient radiation dose. We expect it to play a significant role in determining both quality and robustness of patient non-gated radiotherapy plan.« less

Comparison of the efficiency between two sampling plans for aflatoxins analysis in maize

PubMed Central

Mallmann, Adriano Olnei; Marchioro, Alexandro; Oliveira, Maurício Schneider; Rauber, Ricardo Hummes; Dilkin, Paulo; Mallmann, Carlos Augusto

2014-01-01

Variance and performance of two sampling plans for aflatoxins quantification in maize were evaluated. Eight lots of maize were sampled using two plans: manual, using sampling spear for kernels; and automatic, using a continuous flow to collect milled maize. Total variance and sampling, preparation, and analysis variance were determined and compared between plans through multifactor analysis of variance. Four theoretical distribution models were used to compare aflatoxins quantification distributions in eight maize lots. The acceptance and rejection probabilities for a lot under certain aflatoxin concentration were determined using variance and the information on the selected distribution model to build the operational characteristic curves (OC). Sampling and total variance were lower at the automatic plan. The OC curve from the automatic plan reduced both consumer and producer risks in comparison to the manual plan. The automatic plan is more efficient than the manual one because it expresses more accurately the real aflatoxin contamination in maize. PMID:24948911

Nonparametric triple collocation

USDA-ARS?s Scientific Manuscript database

Triple collocation derives variance-covariance relationships between three or more independent measurement sources and an indirectly observed truth variable in the case where the measurement operators are linear-Gaussian. We generalize that theory to arbitrary observation operators by deriving nonpa...

40 CFR 610.23 - Operator interaction effects.

Code of Federal Regulations, 2010 CFR

2010-07-01

... degree of sensitivity of device effectiveness to variances in installation, operation and maintenance; (b..., operation and maintenance; (c) The extent to which device installation or use, or the effects of such... between total cost of ownership of the device (purchase price plus maintenance costs) and the cost savings...

Hydrograph variances over different timescales in hydropower production networks

NASA Astrophysics Data System (ADS)

Zmijewski, Nicholas; Wörman, Anders

2016-08-01

The operation of water reservoirs involves a spectrum of timescales based on the distribution of stream flow travel times between reservoirs, as well as the technical, environmental, and social constraints imposed on the operation. In this research, a hydrodynamically based description of the flow between hydropower stations was implemented to study the relative importance of wave diffusion on the spectrum of hydrograph variance in a regulated watershed. Using spectral decomposition of the effluence hydrograph of a watershed, an exact expression of the variance in the outflow response was derived, as a function of the trends of hydraulic and geomorphologic dispersion and management of production and reservoirs. We show that the power spectra of involved time-series follow nearly fractal patterns, which facilitates examination of the relative importance of wave diffusion and possible changes in production demand on the outflow spectrum. The exact spectral solution can also identify statistical bounds of future demand patterns due to limitations in storage capacity. The impact of the hydraulic description of the stream flow on the reservoir discharge was examined for a given power demand in River Dalälven, Sweden, as function of a stream flow Peclet number. The regulation of hydropower production on the River Dalälven generally increased the short-term variance in the effluence hydrograph, whereas wave diffusion decreased the short-term variance over periods of <1 week, depending on the Peclet number (Pe) of the stream reach. This implies that flow variance becomes more erratic (closer to white noise) as a result of current production objectives.

5-Aminolevulinic Acid-Induced Protoporphyrin IX Fluorescence in Meningioma: Qualitative and Quantitative Measurements In Vivo

PubMed Central

Valdes, Pablo A.; Bekelis, Kimon; Harris, Brent T.; Wilson, Brian C.; Leblond, Frederic; Kim, Anthony; Simmons, Nathan E.; Erkmen, Kadir; Paulsen, Keith D.; Roberts, David W.

2014-01-01

BACKGROUND The use of 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence has shown promise as a surgical adjunct for maximizing the extent of surgical resection in gliomas. To date, the clinical utility of 5-ALA in meningiomas is not fully understood, with most descriptive studies using qualitative approaches to 5-ALA-PpIX. OBJECTIVE To assess the diagnostic performance of 5-ALA-PpIX fluorescence during surgical resection of meningioma. METHODS ALA was administered to 15 patients with meningioma undergoing PpIX fluorescence-guided surgery at our institution. At various points during the procedure, the surgeon performed qualitative, visual assessments of fluorescence by using the surgical microscope, followed by a quantitative fluorescence measurement by using an intra-operative probe. Specimens were collected at each point for subsequent neuropathological analysis. Clustered data analysis of variance was used to ascertain a difference between groups, and receiver operating characteristic analyses were performed to assess diagnostic capabilities. RESULTS Red-pink fluorescence was observed in 80% (12/15) of patients, with visible fluorescence generally demonstrating a strong, homogenous character. Quantitative fluorescence measured diagnostically significant PpIX concentrations (CPpIx) in both visibly and nonvisibly fluorescent tissues, with significantly higher CPpIx in both visibly fluorescent (P < .001) and tumor tissue (P = .002). Receiver operating characteristic analyses also showed diagnostic accuracies up to 90% for differentiating tumor from normal dura. CONCLUSION ALA-induced PpIX fluorescence guidance is a potential and promising adjunct in accurately detecting neoplastic tissue during meningioma resective surgery. These results suggest a broader reach for PpIX as a biomarker for meningiomas than was previously noted in the literature. PMID:23887194

Time-dependent summary receiver operating characteristics for meta-analysis of prognostic studies.

PubMed

Hattori, Satoshi; Zhou, Xiao-Hua

2016-11-20

Prognostic studies are widely conducted to examine whether biomarkers are associated with patient's prognoses and play important roles in medical decisions. Because findings from one prognostic study may be very limited, meta-analyses may be useful to obtain sound evidence. However, prognostic studies are often analyzed by relying on a study-specific cut-off value, which can lead to difficulty in applying the standard meta-analysis techniques. In this paper, we propose two methods to estimate a time-dependent version of the summary receiver operating characteristics curve for meta-analyses of prognostic studies with a right-censored time-to-event outcome. We introduce a bivariate normal model for the pair of time-dependent sensitivity and specificity and propose a method to form inferences based on summary statistics reported in published papers. This method provides a valid inference asymptotically. In addition, we consider a bivariate binomial model. To draw inferences from this bivariate binomial model, we introduce a multiple imputation method. The multiple imputation is found to be approximately proper multiple imputation, and thus the standard Rubin's variance formula is justified from a Bayesian view point. Our simulation study and application to a real dataset revealed that both methods work well with a moderate or large number of studies and the bivariate binomial model coupled with the multiple imputation outperforms the bivariate normal model with a small number of studies. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Some refinements on the comparison of areal sampling methods via simulation

Treesearch

Jeffrey Gove

2017-01-01

The design of forest inventories and development of new sampling methods useful in such inventories normally have a two-fold target of design unbiasedness and minimum variance in mind. Many considerations such as costs go into the choices of sampling method for operational and other levels of inventory. However, the variance in terms of meeting a specified level of...

Young Adults Seeking Medical Care: Do Race and Ethnicity Matter?

MedlinePlus

... services were sought or received. Data source and methods Data from the 2008 and 2009 NHIS were ... design of the NHIS. The Taylor series linearization method was chosen for variance estimation. All estimates shown ...

A Constrained Least Squares Approach to Mobile Positioning: Algorithms and Optimality

NASA Astrophysics Data System (ADS)

Cheung, KW; So, HC; Ma, W.-K.; Chan, YT

2006-12-01

The problem of locating a mobile terminal has received significant attention in the field of wireless communications. Time-of-arrival (TOA), received signal strength (RSS), time-difference-of-arrival (TDOA), and angle-of-arrival (AOA) are commonly used measurements for estimating the position of the mobile station. In this paper, we present a constrained weighted least squares (CWLS) mobile positioning approach that encompasses all the above described measurement cases. The advantages of CWLS include performance optimality and capability of extension to hybrid measurement cases (e.g., mobile positioning using TDOA and AOA measurements jointly). Assuming zero-mean uncorrelated measurement errors, we show by mean and variance analysis that all the developed CWLS location estimators achieve zero bias and the Cramér-Rao lower bound approximately when measurement error variances are small. The asymptotic optimum performance is also confirmed by simulation results.

Precision of Four Acoustic Bone Measurement Devices

NASA Technical Reports Server (NTRS)

Miller, Christopher; Feiveson, Alan H.; Shackelford, Linda; Rianon, Nahida; LeBlanc, Adrian

2000-01-01

Though many studies have quantified the precision of various acoustic bone measurement devices, it is difficult to directly compare the results among the studies, because they used disparate subject pools, did not specify the estimation methodology, or did not use consistent definitions for various precision characteristics. In this study, we used a repeated measures design protocol to directly determine the precision characteristics of four acoustic bone measurement devices: the Mechanical Response Tissue Analyzer (MRTA), the UBA-575+, the SoundScan 2000 (S2000), and the Sahara Ultrasound Done Analyzer. Ten men and ten women were scanned on all four devices by two different operators at five discrete time points: Week 1, Week 2, Week 3, Month 3 and Month 6. The percent coefficient of variation (%CV) and standardized coefficient of variation were computed for the following precision characteristics: interoperator effect, operator-subject interaction, short-term error variance, and long-term drift, The MRTA had high interoperator errors for its ulnar and tibial stiffness measures and a large long-term drift in its tibial stiffness measurement. The UBA-575+ exhibited large short-term error variances and long-term drift for all three of its measurements. The S2000's tibial speed of sound measurement showed a high short-term error variance and a significant operator-subject interaction but very good values ( < 1%) for the other precision characteristics. The Sahara seemed to have the best overall performance, but was hampered by a large %CV for short-term error variance in its broadband ultrasound attenuation measure.

Precision of Four Acoustic Bone Measurement Devices

NASA Technical Reports Server (NTRS)

Miller, Christopher; Rianon, Nahid; Feiveson, Alan; Shackelford, Linda; LeBlanc, Adrian

2000-01-01

Though many studies have quantified the precision of various acoustic bone measurement devices, it is difficult to directly compare the results among the studies, because they used disparate subject pools, did not specify the estimation methodology, or did not use consistent definitions for various precision characteristics. In this study, we used a repeated measures design protocol to directly determine the precision characteristics of four acoustic bone measurement devices: the Mechanical Response Tissue Analyzer (MRTA), the UBA-575+, the SoundScan 2000 (S2000), and the Sahara Ultrasound Bone Analyzer. Ten men and ten women were scanned on all four devices by two different operators at five discrete time points: Week 1, Week 2, Week 3, Month 3 and Month 6. The percent coefficient of variation (%CV) and standardized coefficient of variation were computed for the following precision characteristics: interoperator effect, operator-subject interaction, short-term error variance, and long-term drift. The MRTA had high interoperator errors for its ulnar and tibial stiffness measures and a large long-term drift in its tibial stiffness measurement. The UBA-575+ exhibited large short-term error variances and long-term drift for all three of its measurements. The S2000's tibial speed of sound measurement showed a high short-term error variance and a significant operator-subject interaction but very good values (less than 1%) for the other precision characteristics. The Sahara seemed to have the best overall performance, but was hampered by a large %CV for short-term error variance in its broadband ultrasound attenuation measure.

Improvement of the quality of work in a biochemistry laboratory via measurement system analysis.

PubMed

Chen, Ming-Shu; Liao, Chen-Mao; Wu, Ming-Hsun; Lin, Chih-Ming

2016-10-31

An adequate and continuous monitoring of operational variations can effectively reduce the uncertainty and enhance the quality of laboratory reports. This study applied the evaluation rule of the measurement system analysis (MSA) method to estimate the quality of work conducted in a biochemistry laboratory. Using the gauge repeatability & reproducibility (GR&R) approach, variations in quality control (QC) data among medical technicians in conducting measurements of five biochemical items, namely, serum glucose (GLU), aspartate aminotransferase (AST), uric acid (UA), sodium (Na) and chloride (Cl), were evaluated. The measurements of the five biochemical items showed different levels of variance among the different technicians, with the variances in GLU measurements being higher than those for the other four items. The ratios of precision-to-tolerance (P/T) for Na, Cl and GLU were all above 0.5, implying inadequate gauge capability. The product variation contribution of Na was large (75.45% and 31.24% in normal and abnormal QC levels, respectively), which showed that the impact of insufficient usage of reagents could not be excluded. With regard to reproducibility, high contributions (of more than 30%) of variation for the selected items were found. These high operator variation levels implied that the possibility of inadequate gauge capacity could not be excluded. The analysis of variance (ANOVA) of GR&R showed that the operator variations in GLU measurements were significant (F=5.296, P=0.001 in the normal level and F=3.399, P=0.015 in the abnormal level, respectively). In addition to operator variations, product variations of Na were also significant for both QC levels. The heterogeneity of variance for the five technicians showed significant differences for the Na and Cl measurements in the normal QC level. The accuracy of QC for five technicians was identified for further operational improvement. This study revealed that MSA can be used to evaluate product and personnel errors and to improve the quality of work in a biochemical laboratory through proper corrective actions.

Performances on the CogState and standard neuropsychological batteries among HIV patients without dementia.

PubMed

Overton, Edgar Turner; Kauwe, John S K; Paul, Robert; Tashima, Karen; Tate, David F; Patel, Pragna; Carpenter, Charles C J; Patty, David; Brooks, John T; Clifford, David B

2011-11-01

HIV-associated neurocognitive disorders remain prevalent but challenging to diagnose particularly among non-demented individuals. To determine whether a brief computerized battery correlates with formal neurocognitive testing, we identified 46 HIV-infected persons who had undergone both formal neurocognitive testing and a brief computerized battery. Simple detection tests correlated best with formal neuropsychological testing. By multivariable regression model, 53% of the variance in the composite Global Deficit Score was accounted for by elements from the brief computerized tool (P < 0.01). These data confirm previous correlation data with the computerized battery. Using the five significant parameters from the regression model in a Receiver Operating Characteristic curve, 90% of persons were accurately classified as being cognitively impaired or not. The test battery requires additional evaluation, specifically for identifying persons with mild impairment, a state upon which interventions may be effective.

Nonparametric EROC analysis for observer performance evaluation on joint detection and estimation tasks

NASA Astrophysics Data System (ADS)

Wunderlich, Adam; Goossens, Bart

2014-03-01

The majority of the literature on task-based image quality assessment has focused on lesion detection tasks, using the receiver operating characteristic (ROC) curve, or related variants, to measure performance. However, since many clinical image evaluation tasks involve both detection and estimation (e.g., estimation of kidney stone composition, estimation of tumor size), there is a growing interest in performance evaluation for joint detection and estimation tasks. To evaluate observer performance on such tasks, Clarkson introduced the estimation ROC (EROC) curve, and the area under the EROC curve as a summary figure of merit. In the present work, we propose nonparametric estimators for practical EROC analysis from experimental data, including estimators for the area under the EROC curve and its variance. The estimators are illustrated with a practical example comparing MRI images reconstructed from different k-space sampling trajectories.

Detecting the Presence of a Personality Disorder Using Interpersonal and Self-Dysfunction.

PubMed

Beeney, Joseph E; Lazarus, Sophie A; Hallquist, Michael N; Stepp, Stephanie D; Wright, Aidan G C; Scott, Lori N; Giertych, Rachel A; Pilkonis, Paul A

2018-03-05

Calls have increased to place interpersonal and self-disturbance as defining features of personality disorders (PDs). Findings from a methodologically diverse set of studies suggest that a common factor undergirds all PDs. The nature of this core of PDs, however, is not clear. In the current study, interviews were completed for DSM-IV PD diagnosis and interpersonal dysfunction independently with 272 individuals (PD = 191, no-PD = 91). Specifically, we evaluated interpersonal dysfunction across social domains. In addition, we empirically assessed the structure of self-dysfunction in PDs. We found dysfunction in work and romantic domains, and unstable identity uniquely predicted variance in the presence of a PD. Using receiver operating characteristic analysis, we found that the interpersonal dysfunction and self-dysfunction scales each predicted PDs with high accuracy. In combination, the scales resulted in excellent sensitivity (.90) and specificity (.88). The results support interpersonal and self-dysfunction as general factors of PD.

Identifying Children in Middle Childhood Who Are at Risk for Reading Problems.

PubMed

Speece, Deborah L; Ritchey, Kristen D; Silverman, Rebecca; Schatschneider, Christopher; Walker, Caroline Y; Andrusik, Katryna N

2010-06-01

The purpose of this study was to identify and evaluate a universal screening battery for reading that is appropriate for older elementary students in a response to intervention model. Multiple measures of reading and reading correlates were administered to 230 fourth-grade children. Teachers rated children's reading skills, academic competence, and attention. Children were classified as not-at-risk or at-risk readers based on a three-factor model reflecting reading comprehension, word recognition/decoding, and word fluency. Predictors of reading status included group-administered tests of reading comprehension, silent word reading fluency, and teacher ratings of reading problems. Inclusion of individually administered tests and growth estimates did not add substantial variance. The receiver-operator characteristic curve analysis yielded an area under the curve index of 0.90, suggesting this model may both accurately and efficiently screen older elementary students with reading problems.

Comparing two correlated C indices with right-censored survival outcome: a one-shot nonparametric approach

PubMed Central

Kang, Le; Chen, Weijie; Petrick, Nicholas A.; Gallas, Brandon D.

2014-01-01

The area under the receiver operating characteristic (ROC) curve (AUC) is often used as a summary index of the diagnostic ability in evaluating biomarkers when the clinical outcome (truth) is binary. When the clinical outcome is right-censored survival time, the C index, motivated as an extension of AUC, has been proposed by Harrell as a measure of concordance between a predictive biomarker and the right-censored survival outcome. In this work, we investigate methods for statistical comparison of two diagnostic or predictive systems, of which they could either be two biomarkers or two fixed algorithms, in terms of their C indices. We adopt a U-statistics based C estimator that is asymptotically normal and develop a nonparametric analytical approach to estimate the variance of the C estimator and the covariance of two C estimators. A z-score test is then constructed to compare the two C indices. We validate our one-shot nonparametric method via simulation studies in terms of the type I error rate and power. We also compare our one-shot method with resampling methods including the jackknife and the bootstrap. Simulation results show that the proposed one-shot method provides almost unbiased variance estimations and has satisfactory type I error control and power. Finally, we illustrate the use of the proposed method with an example from the Framingham Heart Study. PMID:25399736

Value of MR histogram analyses for prediction of microvascular invasion of hepatocellular carcinoma

PubMed Central

Huang, Ya-Qin; Liang, He-Yue; Yang, Zhao-Xia; Ding, Ying; Zeng, Meng-Su; Rao, Sheng-Xiang

2016-01-01

Abstract The objective is to explore the value of preoperative magnetic resonance (MR) histogram analyses in predicting microvascular invasion (MVI) of hepatocellular carcinoma (HCC). Fifty-one patients with histologically confirmed HCC who underwent diffusion-weighted and contrast-enhanced MR imaging were included. Histogram analyses were performed and mean, variance, skewness, kurtosis, 1th, 10th, 50th, 90th, and 99th percentiles were derived. Quantitative histogram parameters were compared between HCCs with and without MVI. Receiver operating characteristics (ROC) analyses were generated to compare the diagnostic performance of tumor size, histogram analyses of apparent diffusion coefficient (ADC) maps, and MR enhancement. The mean, 1th, 10th, and 50th percentiles of ADC maps, and the mean, variance. 1th, 10th, 50th, 90th, and 99th percentiles of the portal venous phase (PVP) images were significantly different between the groups with and without MVI (P <0.05), with area under the ROC curves (AUCs) of 0.66 to 0.74 for ADC and 0.76 to 0.88 for PVP. The largest AUC of PVP (1th percentile) showed significantly higher accuracy compared with that of arterial phase (AP) or tumor size (P <0.001). MR histogram analyses—in particular for 1th percentile for PVP images—held promise for prediction of MVI of HCC. PMID:27368028

Some Memories are Odder than Others: Judgments of Episodic Oddity Violate Known Decision Rules

PubMed Central

O’Connor, Akira R.; Guhl, Emily N.; Cox, Justin C.; Dobbins, Ian G.

2011-01-01

Current decision models of recognition memory are based almost entirely on one paradigm, single item old/new judgments accompanied by confidence ratings. This task results in receiver operating characteristics (ROCs) that are well fit by both signal-detection and dual-process models. Here we examine an entirely new recognition task, the judgment of episodic oddity, whereby participants select the mnemonically odd members of triplets (e.g., a new item hidden among two studied items). Using the only two known signal-detection rules of oddity judgment derived from the sensory perception literature, the unequal variance signal-detection model predicted that an old item among two new items would be easier to discover than a new item among two old items. In contrast, four separate empirical studies demonstrated the reverse pattern: triplets with two old items were the easiest to resolve. This finding was anticipated by the dual-process approach as the presence of two old items affords the greatest opportunity for recollection. Furthermore, a bootstrap-fed Monte Carlo procedure using two independent datasets demonstrated that the dual-process parameters typically observed during single item recognition correctly predict the current oddity findings, whereas unequal variance signal-detection parameters do not. Episodic oddity judgments represent a case where dual- and single-process predictions qualitatively diverge and the findings demonstrate that novelty is “odder” than familiarity. PMID:22833695

Isolating and Examining Sources of Suppression and Multicollinearity in Multiple Linear Regression.

PubMed

Beckstead, Jason W

2012-03-30

The presence of suppression (and multicollinearity) in multiple regression analysis complicates interpretation of predictor-criterion relationships. The mathematical conditions that produce suppression in regression analysis have received considerable attention in the methodological literature but until now nothing in the way of an analytic strategy to isolate, examine, and remove suppression effects has been offered. In this article such an approach, rooted in confirmatory factor analysis theory and employing matrix algebra, is developed. Suppression is viewed as the result of criterion-irrelevant variance operating among predictors. Decomposition of predictor variables into criterion-relevant and criterion-irrelevant components using structural equation modeling permits derivation of regression weights with the effects of criterion-irrelevant variance omitted. Three examples with data from applied research are used to illustrate the approach: the first assesses child and parent characteristics to explain why some parents of children with obsessive-compulsive disorder accommodate their child's compulsions more so than do others, the second examines various dimensions of personal health to explain individual differences in global quality of life among patients following heart surgery, and the third deals with quantifying the relative importance of various aptitudes for explaining academic performance in a sample of nursing students. The approach is offered as an analytic tool for investigators interested in understanding predictor-criterion relationships when complex patterns of intercorrelation among predictors are present and is shown to augment dominance analysis.

Relating the Hadamard Variance to MCS Kalman Filter Clock Estimation

NASA Technical Reports Server (NTRS)

Hutsell, Steven T.

1996-01-01

The Global Positioning System (GPS) Master Control Station (MCS) currently makes significant use of the Allan Variance. This two-sample variance equation has proven excellent as a handy, understandable tool, both for time domain analysis of GPS cesium frequency standards, and for fine tuning the MCS's state estimation of these atomic clocks. The Allan Variance does not explicitly converge for the nose types of alpha less than or equal to minus 3 and can be greatly affected by frequency drift. Because GPS rubidium frequency standards exhibit non-trivial aging and aging noise characteristics, the basic Allan Variance analysis must be augmented in order to (a) compensate for a dynamic frequency drift, and (b) characterize two additional noise types, specifically alpha = minus 3, and alpha = minus 4. As the GPS program progresses, we will utilize a larger percentage of rubidium frequency standards than ever before. Hence, GPS rubidium clock characterization will require more attention than ever before. The three sample variance, commonly referred to as a renormalized Hadamard Variance, is unaffected by linear frequency drift, converges for alpha is greater than minus 5, and thus has utility for modeling noise in GPS rubidium frequency standards. This paper demonstrates the potential of Hadamard Variance analysis in GPS operations, and presents an equation that relates the Hadamard Variance to the MCS's Kalman filter process noises.

Comparison of carprofen and meloxicam for 72 hours following ovariohysterectomy in dogs.

PubMed

Leece, Elizabeth A; Brearley, Jacqueline C; Harding, Edward F

2005-07-01

To compare the peri- and post-operative (72 hours) analgesic effects of injectable and orally administered carprofen and meloxicam for ovariohysterectomy in dogs. Prospective, randomized clinical study. Forty-three dogs undergoing elective ovariohysterectomy. Dogs were randomly assigned to receive pre-operative carprofen, meloxicam or sterile saline by subcutaneous injection. Pre-anaesthetic medication was intramuscular acepromazine (0.02 mg kg(-1)) and methadone (0.2 mg kg(-1)). Anaesthesia was induced with either thiopentone or propofol injected to effect, and maintained with isoflurane in oxygen. Visual analogue scores (VAS) for pain and sedation were recorded at 1, 2, 3, 4 and 6 hours following tracheal extubation. Oral medication with the same treatment was continued post-operatively for 3 days, with VAS scores for pain being recorded before, and 2 hours after treatment on each day. Differences between group age, body mass, duration of general anaesthesia, time from treatment injection to tracheal extubation and time from treatment injection to first oral treatment were analysed using one-way analysis of variance and Kruskal-Wallis test. Visual analogue scores for pain and sedation were analysed using a re-randomization method. The significance level was set at p < 0.05. Meloxicam-treated subjects had lower mean VAS than the control group at 2 and 6 hours following tracheal extubation. Control group VAS were more varied than meloxicam scores (at 6 hours) and carprofen scores (at 3 and 6 hours). On the first post-operative day, pre- to post-treatment VAS scores decreased significantly after meloxicam. On day 3, scores in the meloxicam-treated group were significantly lower than control values after treatment. Changes in pre- to post-treatment VAS were greater in animals receiving either meloxicam or carprofen compared with those given saline. Both carprofen and meloxicam provided satisfactory analgesia for 72 hours following ovariohysterectomy in dogs.

Variance Estimation for NAEP Data Using a Resampling-Based Approach: An Application of Cognitive Diagnostic Models. Research Report. ETS RR-10-26

ERIC Educational Resources Information Center

Hsieh, Chueh-an; Xu, Xueli; von Davier, Matthias

2010-01-01

This paper presents an application of a jackknifing approach to variance estimation of ability inferences for groups of students, using a multidimensional discrete model for item response data. The data utilized to demonstrate the approach come from the National Assessment of Educational Progress (NAEP). In contrast to the operational approach…

Improving Operations Management Concept Recollection via the Zarco Experiential Learning Activity

ERIC Educational Resources Information Center

Polito, Tony; Kros, John; Watson, Kevin

2004-01-01

In this study, the authors investigated the effect of Zarco, an operations management "mock factory" experiential learning activity, on student recollection of operations management concepts. Using a number of single-factor and multiple-factor analyses of variance, the authors compared the recollection of students treated with the Zarco activity…

Uncertainty importance analysis using parametric moment ratio functions.

PubMed

Wei, Pengfei; Lu, Zhenzhou; Song, Jingwen

2014-02-01

This article presents a new importance analysis framework, called parametric moment ratio function, for measuring the reduction of model output uncertainty when the distribution parameters of inputs are changed, and the emphasis is put on the mean and variance ratio functions with respect to the variances of model inputs. The proposed concepts efficiently guide the analyst to achieve a targeted reduction on the model output mean and variance by operating on the variances of model inputs. The unbiased and progressive unbiased Monte Carlo estimators are also derived for the parametric mean and variance ratio functions, respectively. Only a set of samples is needed for implementing the proposed importance analysis by the proposed estimators, thus the computational cost is free of input dimensionality. An analytical test example with highly nonlinear behavior is introduced for illustrating the engineering significance of the proposed importance analysis technique and verifying the efficiency and convergence of the derived Monte Carlo estimators. Finally, the moment ratio function is applied to a planar 10-bar structure for achieving a targeted 50% reduction of the model output variance. © 2013 Society for Risk Analysis.

Cost accounting, management control, and planning in health care.

PubMed

Siegrist, R B; Blish, C S

1988-02-01

Advantages and pharmacy applications of computerized hospital management-control and planning systems are described. Hospitals must define their product lines; patient cases, not tests or procedures, are the end product. Management involves operational control, management control, and strategic planning. Operational control deals with day-to-day management on the task level. Management control involves ensuring that managers use resources effectively and efficiently to accomplish the organization's objectives. Management control includes both control of unit costs of intermediate products, which are procedures and services used to treat patients and are managed by hospital department heads, and control of intermediate product use per case (managed by the clinician). Information from the operation and management levels feeds into the strategic plan; conversely, the management level controls the plan and the operational level carries it out. In the system developed at New England Medical Center, Boston, Massachusetts, the intermediate product-management system enables managers to identify intermediate products, develop standard costs, simulate changes in departmental costs, and perform variance analysis. The end-product management system creates a patient-level data-base, identifies end products (patient-care groupings), develops standard resource protocols, models alternative assumptions, performs variance analysis, and provides concurrent reporting. Examples are given of pharmacy managers' use of such systems to answer questions in the areas of product costing, product pricing, variance analysis, productivity monitoring, flexible budgeting, modeling and planning, and comparative analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of individualism and the Five-Factor Model in the prediction of performance in a leaderless group discussion.

PubMed

Waldman, David A; Atwater, Leanne E; Davidson, Ronald A

2004-02-01

Personality has seen a resurgence in the work performance literature. The Five-Factor Model (FFM) represents a set of personality factors that has received the most attention in recent years. Despite its popularity, the FFM may not be sufficiently comprehensive to account for relevant variation across performance dimensions or tasks. Accordingly, the present study also considers how individualism may predict additional variance in performance beyond the FFM. The study involved 152 undergraduate students who experienced a leaderless group discussion (LGD) exercise. Results showed that while the FFM accounted for variance in students' LGD performance, individualism (independence) accounted for additional, unique variance. Furthermore, analyses of the group compositions revealed curvilinear relationships between the relative amount of extraversion, conscientiousness, and individualism in relation to group-level performance.

A Hyper-Dense GNSS Receiver Network for Monitoring Time and Spatial Variations of Precipitable Water Vapor (PWV)

NASA Astrophysics Data System (ADS)

Tsuda, T.; Ito, N.; Takeda, Y.; Realini, E.; Shinbori, A.

2016-12-01

We employ the GNSS meteorology technique to measure precipitable water vapor (PWV) from the propagation delay of GNSS signal in the atmosphere. We installed a hyper-dense GNSS network using 15 receivers with a horizontal spacing of 1-2 km in Uji, Japan (Uji network). We also obtained precipitation with a rain gauge at a nearby operational weather station and rain cloud distribution by an X-band radar. We selected 40 days from April 2011 to March 2013, when considerable precipitation was detected. Difference in PWV within 10 km was 3-10 mm during a heavy rain. We found PWV increased 10-20 minutes before a passage of a rain cloud. The maximum value of PWV correlated well with the amount of precipitation on the ground. The variance of PWV between the GNSS sites was enhanced during a heavy rain. For a future practical hyper-dense GNSS network system with many receivers, we consider to use inexpensive single frequency (SF) receivers. Because SF receiver cannot eliminate the ionospheric delay by itself, we interpolate the delay referring the delay measured by the nearby dual frequency (DF) receivers. We investigated ionospheric delay by the Uji network, taking advantages of Quasi-Zenith Satellite System (QZSS) that gives signals at high elevation angles. During a travelling ionospheric disturbance (TID), a wavy structure with a horizontal scale of several tens km was recognized. The ionospheric delay was compensated by a linear and quadratic interpolation, then the resulting error of PWV compared with DF solution was about 1.50 mm in RMS. For a real-time estimation of PWV, we used real-time satellite clock information corrected by GEONET. Difference of PWV between the real-time analysis and the post processing with the final orbit was 0.7 mm in RMS. We estimated an overall error of PWV with a dense SF-receiver network on a real-time basis was 1.7 mm in RMS.

Scintillation statistics measured in an earth-space-earth retroreflector link

NASA Technical Reports Server (NTRS)

Bufton, J. L.

1977-01-01

Scintillation was measured in a vertical path from a ground-based laser transmitter to the Geos 3 satellite and back to a ground-based receiver telescope and, the experimental results were compared with analytical results presented in a companion paper (Bufton, 1977). The normalized variance, the probability density function and the power spectral density of scintillation were all measured. Moments of the satellite scintillation data in terms of normalized variance were lower than expected. The power spectrum analysis suggests that there were scintillation components at frequencies higher than the 250 Hz bandwidth available in the experiment.

A Sociotechnical Systems Approach To Coastal Marine Spatial Planning

DTIC Science & Technology

2016-12-01

the authors followed the MEAD step of identifying variances and creating a matrix of these variances. Then the authors were able to propose methods ...potential politics involved, and the risks involved in proposing and attempting to start up a new marine aquaculture operation. 69 Figure 16. Role...10 16. DLNR Board Responsiveness/Review Time 17. Assessment Value Redesign Suggestions • Have a coordinating group or person (with knowledge

Long memory in patterns of mobile phone usage

NASA Astrophysics Data System (ADS)

Owczarczuk, Marcin

2012-02-01

In this article we show that usage of a mobile phone, i.e. daily series of number of calls made by a customer, exhibits long memory. We use a sample of 4502 postpaid users from a Polish mobile operator and study their two-year billing history. We estimate Hurst exponent by nine estimators: aggregated variance method, differencing the variance, absolute values of the aggregated series, Higuchi's method, residuals of regression, the R/S method, periodogram method, modified periodogram method and Whittle estimator. We also analyze empirically relations between estimators. Long memory implies an inertial effect in clients' behavior which may be used by mobile operators to accelerate usage and gain additional profit.

Intensity non-uniformity correction using N3 on 3-T scanners with multichannel phased array coils

PubMed Central

Boyes, Richard G.; Gunter, Jeff L.; Frost, Chris; Janke, Andrew L.; Yeatman, Thomas; Hill, Derek L.G.; Bernstein, Matt A.; Thompson, Paul M.; Weiner, Michael W.; Schuff, Norbert; Alexander, Gene E.; Killiany, Ronald J.; DeCarli, Charles; Jack, Clifford R.; Fox, Nick C.

2008-01-01

Measures of structural brain change based on longitudinal MR imaging are increasingly important but can be degraded by intensity non-uniformity. This non-uniformity can be more pronounced at higher field strengths, or when using multichannel receiver coils. We assessed the ability of the non-parametric non-uniform intensity normalization (N3) technique to correct non-uniformity in 72 volumetric brain MR scans from the preparatory phase of the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Normal elderly subjects (n = 18) were scanned on different 3-T scanners with a multichannel phased array receiver coil at baseline, using magnetization prepared rapid gradient echo (MP-RAGE) and spoiled gradient echo (SPGR) pulse sequences, and again 2 weeks later. When applying N3, we used five brain masks of varying accuracy and four spline smoothing distances (d = 50, 100, 150 and 200 mm) to ascertain which combination of parameters optimally reduces the non-uniformity. We used the normalized white matter intensity variance (standard deviation/mean) to ascertain quantitatively the correction for a single scan; we used the variance of the normalized difference image to assess quantitatively the consistency of the correction over time from registered scan pairs. Our results showed statistically significant (p < 0.01) improvement in uniformity for individual scans and reduction in the normalized difference image variance when using masks that identified distinct brain tissue classes, and when using smaller spline smoothing distances (e.g., 50-100 mm) for both MP-RAGE and SPGR pulse sequences. These optimized settings may assist future large-scale studies where 3-T scanners and phased array receiver coils are used, such as ADNI, so that intensity non-uniformity does not influence the power of MR imaging to detect disease progression and the factors that influence it. PMID:18063391

[The effect of the ventilation rate on air particle and air microbe concentration in operating rooms with conventional ventilation. 1. Measurement without surgical activity].

PubMed

Kruppa, B; Rüden, H

1993-05-01

The question was if a reduction of airborne particles and bacteria in conventionally (turbulently), ventilated operating theatres in comparison to Laminar-Airflow (LAF) operating theatres does occur at high air-exchange-rates. Within the framework of energy consumption measures the influence of air-exchange-rates on airborne particle and bacteria concentrations was determined in two identical operating theatres with conventional ventilation (wall diffusor panel) at the air-exchange-rates 7.5, 10, 15 and 20/h without surgical activity. This was established by means of the statistical procedure of analysis of variance. Especially for the comparison of the air-exchange-rates 7.5 and 15/h statistical differences were found for airborne particle concentrations in supply and ambient air. Concerning airborne bacteria concentrations no differences were found among the various air-exchange-rates. Explanation of variance is quite high for non-viable particles (supply air: 37%, ambient air: 81%) but negligible for viable particles (bacteria) with values below 15%.

Applying an Evidence-Based Assessment Model to Identify Students at Risk for Perceived Academic Problems following Concussion.

PubMed

Ransom, Danielle M; Burns, Alison R; Youngstrom, Eric A; Vaughan, Christopher G; Sady, Maegan D; Gioia, Gerard A

2016-11-01

The aim of this study was to demonstrate the utility of an evidence-based assessment (EBA) model to establish a multimodal set of tools for identifying students at risk for perceived post-injury academic problems. Participants included 142 students diagnosed with concussion (age: M=14.95; SD=1.80; 59% male), evaluated within 4 weeks of injury (median=16 days). Demographics, pre-injury history, self- and parent-report measures assessing symptom severity and executive functions, and cognitive test performance were examined as predictors of self-reported post-injury academic problems. Latent class analysis categorized participants into "high" (44%) and "low" (56%) levels of self-reported academic problems. Receiver operating characteristic analyses revealed significant discriminative validity for self- and parent-reported symptom severity and executive dysfunction and self-reported exertional response for identifying students reporting low versus high academic problems. Parent-reported symptom ratings [area under the receiver operating characteristic curve (AUC)=.79] and executive dysfunction (AUC=.74), and self-reported ratings of executive dysfunction (AUC=.84), symptoms (AUC=.80), and exertional response (AUC=.70) each classified students significantly better than chance (ps<.001). Hierarchical logistic regression indicated that, of the above, self-reported symptoms and executive dysfunction accounted for the most variance in the prediction of self-reported academic problems. Post-concussion symptom severity and executive dysfunction significantly predict perceived post-injury academic problems. EBA modeling identified the strongest set of predictors of academic challenges, offering an important perspective in the management of concussion by applying traditional strengths of neuropsychological assessment to clinical decision making. (JINS, 2016, 22, 1038-1049).

The ROC Toolbox: A toolbox for analyzing receiver-operating characteristics derived from confidence ratings.

PubMed

Koen, Joshua D; Barrett, Frederick S; Harlow, Iain M; Yonelinas, Andrew P

2017-08-01

Signal-detection theory, and the analysis of receiver-operating characteristics (ROCs), has played a critical role in the development of theories of episodic memory and perception. The purpose of the current paper is to present the ROC Toolbox. This toolbox is a set of functions written in the Matlab programming language that can be used to fit various common signal detection models to ROC data obtained from confidence rating experiments. The goals for developing the ROC Toolbox were to create a tool (1) that is easy to use and easy for researchers to implement with their own data, (2) that can flexibly define models based on varying study parameters, such as the number of response options (e.g., confidence ratings) and experimental conditions, and (3) that provides optimal routines (e.g., Maximum Likelihood estimation) to obtain parameter estimates and numerous goodness-of-fit measures.The ROC toolbox allows for various different confidence scales and currently includes the models commonly used in recognition memory and perception: (1) the unequal variance signal detection (UVSD) model, (2) the dual process signal detection (DPSD) model, and (3) the mixture signal detection (MSD) model. For each model fit to a given data set the ROC toolbox plots summary information about the best fitting model parameters and various goodness-of-fit measures. Here, we present an overview of the ROC Toolbox, illustrate how it can be used to input and analyse real data, and finish with a brief discussion on features that can be added to the toolbox.

Quantifying Seasonal Skill in Coupled Sea Ice Models using Freeboard Measurements from Spaceborne Laser Altimeters

NASA Astrophysics Data System (ADS)

Roberts, A.; Bench, K.; Maslowski, W.; Farrell, S. L.; Richter-Menge, J.

2016-12-01

We have developed a method to quantitatively assess the skill of predictive sea ice models using freeboard measurements from spaceborne laser altimeters. The method evaluates freeboard from the Regional Arctic System Model (RASM) against those derived from NASA ICESat and Operation IceBridge (OIB) missions along individual ground tracks, and assesses the variance- and correlation-weighted model skill. This allows quantifying the accuracy of sea ice volume simulations and taking measurement error into account. As part of this work, we inter-compare simulations with two different sea ice rheologies: one using Elastic-Viscous-Plastic (EVP), and the other using Elastic-Anisotropic-Plastic (EAP) ice mechanics. Both are simulated for 2004 and 2007, during which ICESat was in operation. RASM variance skill scores ranged from 0.712 to 0.824 and correlation skill scores were between 0.319 and 0.511, with EAP providing a better estimate of spatial ice volume variance, but with a larger bias in the central Arctic relative to EVP. The skill scores were calculated for monthly periods and require little adaption to rate short-term operational forecasts of the Arctic. This work will help quantify model limitations and facilitate optimal use of ICESat-2 freeboard measurements after that satellite is launched next year.

[Case allocation of extensive operations on head and neck within the German DRG system 2004-2007: what is the net result of the continued developments in case allocation?].

PubMed

Franz, D; Franz, K; Roeder, N; Hörmann, K; Fischer, R-J; Alberty, Jürgen

2007-07-01

When the German DRG system was implemented there was some doubt about whether patients with extensive head and neck surgery would be properly accounted for. Significant efforts have therefore been invested in analysis and case allocation of those in this group. The object of this study was to investigate whether the changes within the German DRG system have led to improved case allocation. Cost data received from 25 ENT departments on 518 prospective documented cases of extensive head and neck surgery were compared with data from the German institute dealing with remuneration in hospitals (InEK). Statistical measures used by InEK were used to analyse the quality of the overall system and the homogeneity of the individual case groups. The reduction of variance of inlier costs improved by about 107.3% from the 2004 version to the 2007 version of the German DRG system. The average coefficient of cost homogeneity rose by about 9.7% in the same period. Case mix index and DRG revenues were redistributed from less extensive to the more complex operations. Hospitals with large numbers of extensive operations and university hospitals will gain most benefit from this development. Appropriate case allocation of extensive operations on the head and neck has been improved by the continued development of the German DRG system culminating in the 2007 version. Further adjustments will be needed in the future.

Trends in Adults Receiving a Recommendation for Exercise or Other Physical Activity from a Physician or Other Health ...

MedlinePlus

... to exercise or physical activity. Data source and methods National Health Interview Survey (NHIS) data are collected ... sample design of NHIS. The Taylor series linearization method was used for variance estimation. All estimates shown ...

Efficient Strategies for Estimating the Spatial Coherence of Backscatter

PubMed Central

Hyun, Dongwoon; Crowley, Anna Lisa C.; Dahl, Jeremy J.

2017-01-01

The spatial coherence of ultrasound backscatter has been proposed to reduce clutter in medical imaging, to measure the anisotropy of the scattering source, and to improve the detection of blood flow. These techniques rely on correlation estimates that are obtained using computationally expensive strategies. In this study, we assess existing spatial coherence estimation methods and propose three computationally efficient modifications: a reduced kernel, a downsampled receive aperture, and the use of an ensemble correlation coefficient. The proposed methods are implemented in simulation and in vivo studies. Reducing the kernel to a single sample improved computational throughput and improved axial resolution. Downsampling the receive aperture was found to have negligible effect on estimator variance, and improved computational throughput by an order of magnitude for a downsample factor of 4. The ensemble correlation estimator demonstrated lower variance than the currently used average correlation. Combining the three methods, the throughput was improved 105-fold in simulation with a downsample factor of 4 and 20-fold in vivo with a downsample factor of 2. PMID:27913342

Decision support for operations and maintenance (DSOM) system

DOEpatents

Jarrell, Donald B [Kennewick, WA; Meador, Richard J [Richland, WA; Sisk, Daniel R [Richland, WA; Hatley, Darrel D [Kennewick, WA; Brown, Daryl R [Richland, WA; Keibel, Gary R [Richland, WA; Gowri, Krishnan [Richland, WA; Reyes-Spindola, Jorge F [Richland, WA; Adams, Kevin J [San Bruno, CA; Yates, Kenneth R [Lake Oswego, OR; Eschbach, Elizabeth J [Fort Collins, CO; Stratton, Rex C [Richland, WA

2006-03-21

A method for minimizing the life cycle cost of processes such as heating a building. The method utilizes sensors to monitor various pieces of equipment used in the process, for example, boilers, turbines, and the like. The method then performs the steps of identifying a set optimal operating conditions for the process, identifying and measuring parameters necessary to characterize the actual operating condition of the process, validating data generated by measuring those parameters, characterizing the actual condition of the process, identifying an optimal condition corresponding to the actual condition, comparing said optimal condition with the actual condition and identifying variances between the two, and drawing from a set of pre-defined algorithms created using best engineering practices, an explanation of at least one likely source and at least one recommended remedial action for selected variances, and providing said explanation as an output to at least one user.

Statistical Approaches to Adjusting Weights for Dependent Arms in Network Meta-analysis.

PubMed

Su, Yu-Xuan; Tu, Yu-Kang

2018-05-22

Network meta-analysis compares multiple treatments in terms of their efficacy and harm by including evidence from randomized controlled trials. Most clinical trials use parallel design, where patients are randomly allocated to different treatments and receive only one treatment. However, some trials use within person designs such as split-body, split-mouth and cross-over designs, where each patient may receive more than one treatment. Data from treatment arms within these trials are no longer independent, so the correlations between dependent arms need to be accounted for within the statistical analyses. Ignoring these correlations may result in incorrect conclusions. The main objective of this study is to develop statistical approaches to adjusting weights for dependent arms within special design trials. In this study, we demonstrate the following three approaches: the data augmentation approach, the adjusting variance approach, and the reducing weight approach. These three methods could be perfectly applied in current statistic tools such as R and STATA. An example of periodontal regeneration was used to demonstrate how these approaches could be undertaken and implemented within statistical software packages, and to compare results from different approaches. The adjusting variance approach can be implemented within the network package in STATA, while reducing weight approach requires computer software programming to set up the within-study variance-covariance matrix. This article is protected by copyright. All rights reserved.

Identification of Decision Support Concepts for the Planning of Air Force Immediate Contingencies Operations

DTIC Science & Technology

2010-03-01

that is becoming the norm in military operations, especial rapid response. Significance : The context of the work for this project focused on one...Time constraint variance ................................................................... 37 DRDC Valcartier CR 2010-353 xiii 3.5.8.1...employment activities that are normally recurring in nature and fall within the delegated authority of an appointed standing operational Commander

Characterization of Tactical Departure Scheduling in the National Airspace System

NASA Technical Reports Server (NTRS)

Capps, Alan; Engelland, Shawn A.

2011-01-01

This paper discusses and analyzes current day utilization and performance of the tactical departure scheduling process in the National Airspace System (NAS) to understand the benefits in improving this process. The analysis used operational air traffic data from over 1,082,000 flights during the month of January, 2011. Specific metrics included the frequency of tactical departure scheduling, site specific variances in the technology's utilization, departure time prediction compliance used in the tactical scheduling process and the performance with which the current system can predict the airborne slot that aircraft are being scheduled into from the airport surface. Operational data analysis described in this paper indicates significant room for improvement exists in the current system primarily in the area of reduced departure time prediction uncertainty. Results indicate that a significant number of tactically scheduled aircraft did not meet their scheduled departure slot due to departure time uncertainty. In addition to missed slots, the operational data analysis identified increased controller workload associated with tactical departures which were subject to traffic management manual re-scheduling or controller swaps. An analysis of achievable levels of departure time prediction accuracy as obtained by a new integrated surface and tactical scheduling tool is provided to assess the benefit it may provide as a solution to the identified shortfalls. A list of NAS facilities which are likely to receive the greatest benefit from the integrated surface and tactical scheduling technology are provided.

Extending i-line capabilities through variance characterization and tool enhancement

NASA Astrophysics Data System (ADS)

Miller, Dan; Salinas, Adrian; Peterson, Joel; Vickers, David; Williams, Dan

2006-03-01

Continuous economic pressures have moved a large percent of integrated device manufacturing (IDM) operations either overseas or to foundry operations over the last 10 years. These pressures have left the IDM fabs in the U.S. with required COO improvements in order to maintain operations domestically. While the assets of many of these factories are at a very favorable point in the depreciation life cycle, the equipment and processes are constrained to the quality of the equipment in its original state and the degradation over its installed life. With the objective to enhance output and improve process performance, this factory and their primary lithography process tool supplier have been able to extend the usable life of the existing process tools, increase the output of the tool base, and improve the distribution of the CDs on the product produced. Texas Instruments Incorporated lead an investigation with the POLARIS ® Systems & Services business of FSI International to determine the sources of variance in the i-line processing of a wide array of IC device types. Data from the sources of variance were investigated such as PEB temp, PEB delay time, develop recipe, develop time, and develop programming. While PEB processes are a primary driver of acid catalyzed resists, the develop mode is shown in this work to have an overwhelming impact on the wafer to wafer and across wafer CD performance of these i-line processes. These changes have been able to improve the wafer to wafer CD distribution by more than 80 %, and the within wafer CD distribution by more than 50 % while enabling a greater than 50 % increase in lithography cluster throughput. The paper will discuss the contribution from each of the sources of variance and their importance in overall system performance.

40 CFR 142.43 - Disposition of a variance request.

Code of Federal Regulations, 2010 CFR

2010-07-01

... information or argument to the Administrator. The Administrator shall make a final determination on the request within 30 days after receiving any such additional information or argument. If no additional information or argument is submitted by the applicant the application shall be denied. (b) If the...

Experimental demonstration of quantum teleportation of a squeezed state

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takei, Nobuyuki; Aoki, Takao; Yonezawa, Hidehiro

2005-10-15

Quantum teleportation of a squeezed state is demonstrated experimentally. Due to some inevitable losses in experiments, a squeezed vacuum necessarily becomes a mixed state which is no longer a minimum uncertainty state. We establish an operational method of evaluation for quantum teleportation of such a state using fidelity and discuss the classical limit for the state. The measured fidelity for the input state is 0.85{+-}0.05, which is higher than the classical case of 0.73{+-}0.04. We also verify that the teleportation process operates properly for the nonclassical state input and its squeezed variance is certainly transferred through the process. We observemore » the smaller variance of the teleported squeezed state than that for the vacuum state input.« less

Interpreting the concordance statistic of a logistic regression model: relation to the variance and odds ratio of a continuous explanatory variable

PubMed Central

2012-01-01

Background When outcomes are binary, the c-statistic (equivalent to the area under the Receiver Operating Characteristic curve) is a standard measure of the predictive accuracy of a logistic regression model. Methods An analytical expression was derived under the assumption that a continuous explanatory variable follows a normal distribution in those with and without the condition. We then conducted an extensive set of Monte Carlo simulations to examine whether the expressions derived under the assumption of binormality allowed for accurate prediction of the empirical c-statistic when the explanatory variable followed a normal distribution in the combined sample of those with and without the condition. We also examine the accuracy of the predicted c-statistic when the explanatory variable followed a gamma, log-normal or uniform distribution in combined sample of those with and without the condition. Results Under the assumption of binormality with equality of variances, the c-statistic follows a standard normal cumulative distribution function with dependence on the product of the standard deviation of the normal components (reflecting more heterogeneity) and the log-odds ratio (reflecting larger effects). Under the assumption of binormality with unequal variances, the c-statistic follows a standard normal cumulative distribution function with dependence on the standardized difference of the explanatory variable in those with and without the condition. In our Monte Carlo simulations, we found that these expressions allowed for reasonably accurate prediction of the empirical c-statistic when the distribution of the explanatory variable was normal, gamma, log-normal, and uniform in the entire sample of those with and without the condition. Conclusions The discriminative ability of a continuous explanatory variable cannot be judged by its odds ratio alone, but always needs to be considered in relation to the heterogeneity of the population. PMID:22716998

Analysis of a genetically structured variance heterogeneity model using the Box-Cox transformation.

PubMed

Yang, Ye; Christensen, Ole F; Sorensen, Daniel

2011-02-01

Over recent years, statistical support for the presence of genetic factors operating at the level of the environmental variance has come from fitting a genetically structured heterogeneous variance model to field or experimental data in various species. Misleading results may arise due to skewness of the marginal distribution of the data. To investigate how the scale of measurement affects inferences, the genetically structured heterogeneous variance model is extended to accommodate the family of Box-Cox transformations. Litter size data in rabbits and pigs that had previously been analysed in the untransformed scale were reanalysed in a scale equal to the mode of the marginal posterior distribution of the Box-Cox parameter. In the rabbit data, the statistical evidence for a genetic component at the level of the environmental variance is considerably weaker than that resulting from an analysis in the original metric. In the pig data, the statistical evidence is stronger, but the coefficient of correlation between additive genetic effects affecting mean and variance changes sign, compared to the results in the untransformed scale. The study confirms that inferences on variances can be strongly affected by the presence of asymmetry in the distribution of data. We recommend that to avoid one important source of spurious inferences, future work seeking support for a genetic component acting on environmental variation using a parametric approach based on normality assumptions confirms that these are met.

Influence of Random DC Offsets on Burst-Mode Receiver Sensitivity

NASA Astrophysics Data System (ADS)

Ossieur, Peter; de Ridder, Tine; Qiu, Xing-Zhi; Vandewege, Jan

2006-03-01

This paper presents the influence of random direct current (dc) offsets on the sensitivity of dc-coupled burst-mode receivers (BMRxs). It is well known that a BMRx exhibits a noisy decision threshold, resulting in a sensitivity penalty. If the BMRx is dc coupled, an additional penalty is incurred by random dc offsets. This penalty can only be determined for a statistically significant number of fabricated BMRx samples. Using Monte Carlo (MC) simulations and a detailed BMRx model, the relationship between the variance of this random dc offset, the resulting sensitivity penalty, and BMRx yield (the fraction of fabricated BMRx samples that meets a given sensitivity specification) is evaluated as a function of various receiver parameters. The obtained curves can be used to trade off BMRx die area against sensitivity for a given yield. It is demonstrated that a thorough understanding of the relationship between BMRx sensitivity, BMRx yield, and the variance of the random dc offsets is needed to optimize a dc-coupled BMRx with respect to sensitivity and die area for a given yield. It is shown that compensation of dc offsets with a resolution of 8 bits results in a sensitivity penalty of 1 dB for a wide range of random dc offsets.

29 CFR 1954.20 - Complaints about State program administration.

Code of Federal Regulations, 2010 CFR

2010-07-01

... pattern of delays in processing cases, of inadequate workplace inspections, or the granting of variances... investigation should be made, he shall cause such investigation, including any workplace inspection, to be made... complaints received on the same or similar issues and whether the complaints relate to safety and health...

Pessimism, Trauma, Risky Sex: Covariates of Depression in College Students

ERIC Educational Resources Information Center

Swanholm, Eric; Vosvick, Mark; Chng, Chwee-Lye

2009-01-01

Objective: To explain variance in depression in students (N = 648) using a model incorporating sexual trauma, pessimism, and risky sex. Method: Survey data collected from undergraduate students receiving credit for participation. Results: Controlling for demographics, a hierarchical linear regression analysis [Adjusted R[superscript 2] = 0.34,…

SU-G-TeP1-05: Development and Clinical Introduction of Automated Radiotherapy Treatment Planning for Prostate Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Winkel, D; Bol, GH; Asselen, B van

Purpose: To develop an automated radiotherapy treatment planning and optimization workflow for prostate cancer in order to generate clinical treatment plans. Methods: A fully automated radiotherapy treatment planning and optimization workflow was developed based on the treatment planning system Monaco (Elekta AB, Stockholm, Sweden). To evaluate our method, a retrospective planning study (n=100) was performed on patients treated for prostate cancer with 5 field intensity modulated radiotherapy, receiving a dose of 35×2Gy to the prostate and vesicles and a simultaneous integrated boost of 35×0.2Gy to the prostate only. A comparison was made between the dosimetric values of the automatically andmore » manually generated plans. Operator time to generate a plan and plan efficiency was measured. Results: A comparison of the dosimetric values show that automatically generated plans yield more beneficial dosimetric values. In automatic plans reductions of 43% in the V72Gy of the rectum and 13% in the V72Gy of the bladder are observed when compared to the manually generated plans. Smaller variance in dosimetric values is seen, i.e. the intra- and interplanner variability is decreased. For 97% of the automatically generated plans and 86% of the clinical plans all criteria for target coverage and organs at risk constraints are met. The amount of plan segments and monitor units is reduced by 13% and 9% respectively. Automated planning requires less than one minute of operator time compared to over an hour for manual planning. Conclusion: The automatically generated plans are highly suitable for clinical use. The plans have less variance and a large gain in time efficiency has been achieved. Currently, a pilot study is performed, comparing the preference of the clinician and clinical physicist for the automatic versus manual plan. Future work will include expanding our automated treatment planning method to other tumor sites and develop other automated radiotherapy workflows.« less

Effectiveness of facilitated introduction of a standard operating procedure into routine processes in the operating theatre: a controlled interrupted time series.

PubMed

Morgan, Lauren; New, Steve; Robertson, Eleanor; Collins, Gary; Rivero-Arias, Oliver; Catchpole, Ken; Pickering, Sharon P; Hadi, Mohammed; Griffin, Damian; McCulloch, Peter

2015-02-01

Standard operating procedures (SOPs) should improve safety in the operating theatre, but controlled studies evaluating the effect of staff-led implementation are needed. In a controlled interrupted time series, we evaluated three team process measures (compliance with WHO surgical safety checklist, non-technical skills and technical performance) and three clinical outcome measures (length of hospital stay, complications and readmissions) before and after a 3-month staff-led development of SOPs. Process measures were evaluated by direct observation, using Oxford Non-Technical Skills II for non-technical skills and the 'glitch count' for technical performance. All staff in two orthopaedic operating theatres were trained in the principles of SOPs and then assisted to develop standardised procedures. Staff in a control operating theatre underwent the same observations but received no training. The change in difference between active and control groups was compared before and after the intervention using repeated measures analysis of variance. We observed 50 operations before and 55 after the intervention and analysed clinical data on 1022 and 861 operations, respectively. The staff chose to structure their efforts around revising the 'whiteboard' which documented and prompted tasks, rather than directly addressing specific task problems. Although staff preferred and sustained the new system, we found no significant differences in process or outcome measures before/after intervention in the active versus the control group. There was a secular trend towards worse outcomes in the postintervention period, seen in both active and control theatres. SOPs when developed and introduced by frontline staff do not necessarily improve operative processes or outcomes. The inherent tension in improvement work between giving staff ownership of improvement and maintaining control of direction needs to be managed, to ensure staff are engaged but invest energy in appropriate change. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Risk management and market efficiency on the Midwest Independent System Operator electricity exchange

NASA Astrophysics Data System (ADS)

Jones, Kevin

Midwest Independent Transmission System Operator, Inc. (MISO) is a non-profit regional transmission organization (RTO) that oversees electricity production and transmission across thirteen states and one Canadian province. MISO also operates an electronic exchange for buying and selling electricity for each of its five regional hubs. MISO oversees two types of markets. The forward market, which is referred to as the day-ahead (DA) market, allows market participants to place demand bids and supply offers on electricity to be delivered at a specified hour the following day. The equilibrium price, known as the locational marginal price (LMP), is determined by MISO after receiving sale offers and purchase bids from market participants. MISO also coordinates a spot market, which is known as the real-time (RT) market. Traders in the real-time market must submit bids and offers by thirty minutes prior to the hour for which the trade will be executed. After receiving purchase and sale offers for a given hour in the real time market, MISO then determines the LMP for that particular hour. The existence of the DA and RT markets allows producers and retailers to hedge against the large fluctuations that are common in electricity prices. Hedge ratios on the MISO exchange are estimated using various techniques. No hedge ratio technique examined consistently outperforms the unhedged portfolio in terms of variance reduction. Consequently, none of the hedge ratio methods in this study meet the general interpretation of FASB guidelines for a highly effective hedge. One of the major goals of deregulation is to bring about competition and increased efficiency in electricity markets. Previous research suggests that electricity exchanges may not be weak-form market efficient. A simple moving average trading rule is found to produce statistically and economically significant profits on the MISO exchange. This could call the long-term survivability of the MISO exchange into question.

Does a robotic scrub nurse improve economy of movements?

NASA Astrophysics Data System (ADS)

Wachs, Juan P.; Jacob, Mithun; Li, Yu-Ting; Akingba, George

2012-02-01

Objective: Robotic assistance during surgery has been shown to be a useful resource to both augment the surgical skills of the surgeon through tele-operation, and to assist the surgeon handling the surgical instruments to the surgeon, similar to a surgical tech. We evaluated the performance and effect of a gesture driven surgical robotic nurse in the context of economy of movements, during an abdominal incision and closure exercise with a simulator. Methods: A longitudinal midline incision (100 mm) was performed on the simulated abdominal wall to enter the peritoneal cavity without damaging the internal organs. The wound was then closed using a blunt needle ensuring that no tissue is caught up by the suture material. All the instruments required to complete this task were delivered by a robotic surgical manipulator directly to the surgeon. The instruments were requested through voice and gesture recognition. The robotic system used a low end range sensor camera to extract the hand poses and for recognizing the gestures. The instruments were delivered to the vicinity of the patient, at chest height and at a reachable distance to the surgeon. Task performance measures for each of three abdominal incision and closure exercises were measured and compared to a human scrub nurse instrument delivery action. Picking instrument position variance, completion time and trajectory of the hand were recorded for further analysis. Results: The variance of the position of the robotic tip when delivering the surgical instrument is compared to the same position when a human delivers the instrument. The variance was found to be 88.86% smaller compared to the human delivery group. The mean task completion time to complete the surgical exercise was 162.7+/- 10.1 secs for the human assistant and 191.6+/- 3.3 secs (P<.01) when using the robotic standard display group. Conclusion: Multimodal robotic scrub nurse assistant improves the surgical procedure by reducing the number of movements (lower variance in the picking position). The variance of the picking point is closely related to the concept of economy of movements in the operating room. Improving the effectiveness of the operating room can potentially enhance the safety of surgical interventions without affecting the performance time.

Designing a composite correlation filter based on iterative optimization of training images for distortion invariant face recognition

NASA Astrophysics Data System (ADS)

Wang, Q.; Elbouz, M.; Alfalou, A.; Brosseau, C.

2017-06-01

We present a novel method to optimize the discrimination ability and noise robustness of composite filters. This method is based on the iterative preprocessing of training images which can extract boundary and detailed feature information of authentic training faces, thereby improving the peak-to-correlation energy (PCE) ratio of authentic faces and to be immune to intra-class variance and noise interference. By adding the training images directly, one can obtain a composite template with high discrimination ability and robustness for face recognition task. The proposed composite correlation filter does not involve any complicated mathematical analysis and computation which are often required in the design of correlation algorithms. Simulation tests have been conducted to check the effectiveness and feasibility of our proposal. Moreover, to assess robustness of composite filters using receiver operating characteristic (ROC) curves, we devise a new method to count the true positive and false positive rates for which the difference between PCE and threshold is involved.

Segmentation of Coronary Angiograms Using Gabor Filters and Boltzmann Univariate Marginal Distribution Algorithm

PubMed Central

Cervantes-Sanchez, Fernando; Hernandez-Aguirre, Arturo; Solorio-Meza, Sergio; Ornelas-Rodriguez, Manuel; Torres-Cisneros, Miguel

2016-01-01

This paper presents a novel method for improving the training step of the single-scale Gabor filters by using the Boltzmann univariate marginal distribution algorithm (BUMDA) in X-ray angiograms. Since the single-scale Gabor filters (SSG) are governed by three parameters, the optimal selection of the SSG parameters is highly desirable in order to maximize the detection performance of coronary arteries while reducing the computational time. To obtain the best set of parameters for the SSG, the area (A z) under the receiver operating characteristic curve is used as fitness function. Moreover, to classify vessel and nonvessel pixels from the Gabor filter response, the interclass variance thresholding method has been adopted. The experimental results using the proposed method obtained the highest detection rate with A z = 0.9502 over a training set of 40 images and A z = 0.9583 with a test set of 40 images. In addition, the experimental results of vessel segmentation provided an accuracy of 0.944 with the test set of angiograms. PMID:27738422

Error modeling for differential GPS. M.S. Thesis - MIT, 12 May 1995

NASA Technical Reports Server (NTRS)

Blerman, Gregory S.

1995-01-01

Differential Global Positioning System (DGPS) positioning is used to accurately locate a GPS receiver based upon the well-known position of a reference site. In utilizing this technique, several error sources contribute to position inaccuracy. This thesis investigates the error in DGPS operation and attempts to develop a statistical model for the behavior of this error. The model for DGPS error is developed using GPS data collected by Draper Laboratory. The Marquardt method for nonlinear curve-fitting is used to find the parameters of a first order Markov process that models the average errors from the collected data. The results show that a first order Markov process can be used to model the DGPS error as a function of baseline distance and time delay. The model's time correlation constant is 3847.1 seconds (1.07 hours) for the mean square error. The distance correlation constant is 122.8 kilometers. The total process variance for the DGPS model is 3.73 sq meters.

Bayesian multivariate hierarchical transformation models for ROC analysis.

PubMed

O'Malley, A James; Zou, Kelly H

2006-02-15

A Bayesian multivariate hierarchical transformation model (BMHTM) is developed for receiver operating characteristic (ROC) curve analysis based on clustered continuous diagnostic outcome data with covariates. Two special features of this model are that it incorporates non-linear monotone transformations of the outcomes and that multiple correlated outcomes may be analysed. The mean, variance, and transformation components are all modelled parametrically, enabling a wide range of inferences. The general framework is illustrated by focusing on two problems: (1) analysis of the diagnostic accuracy of a covariate-dependent univariate test outcome requiring a Box-Cox transformation within each cluster to map the test outcomes to a common family of distributions; (2) development of an optimal composite diagnostic test using multivariate clustered outcome data. In the second problem, the composite test is estimated using discriminant function analysis and compared to the test derived from logistic regression analysis where the gold standard is a binary outcome. The proposed methodology is illustrated on prostate cancer biopsy data from a multi-centre clinical trial.

Bayesian multivariate hierarchical transformation models for ROC analysis

PubMed Central

O'Malley, A. James; Zou, Kelly H.

2006-01-01

SUMMARY A Bayesian multivariate hierarchical transformation model (BMHTM) is developed for receiver operating characteristic (ROC) curve analysis based on clustered continuous diagnostic outcome data with covariates. Two special features of this model are that it incorporates non-linear monotone transformations of the outcomes and that multiple correlated outcomes may be analysed. The mean, variance, and transformation components are all modelled parametrically, enabling a wide range of inferences. The general framework is illustrated by focusing on two problems: (1) analysis of the diagnostic accuracy of a covariate-dependent univariate test outcome requiring a Box–Cox transformation within each cluster to map the test outcomes to a common family of distributions; (2) development of an optimal composite diagnostic test using multivariate clustered outcome data. In the second problem, the composite test is estimated using discriminant function analysis and compared to the test derived from logistic regression analysis where the gold standard is a binary outcome. The proposed methodology is illustrated on prostate cancer biopsy data from a multi-centre clinical trial. PMID:16217836

Recognition and Classification of Road Condition on the Basis of Friction Force by Using a Mobile Robot

NASA Astrophysics Data System (ADS)

Watanabe, Tatsuhito; Katsura, Seiichiro

A person operating a mobile robot in a remote environment receives realistic visual feedback about the condition of the road on which the robot is moving. The categorization of the road condition is necessary to evaluate the conditions for safe and comfortable driving. For this purpose, the mobile robot should be capable of recognizing and classifying the condition of the road surfaces. This paper proposes a method for recognizing the type of road surfaces on the basis of the friction between the mobile robot and the road surfaces. This friction is estimated by a disturbance observer, and a support vector machine is used to classify the surfaces. The support vector machine identifies the type of the road surface using feature vector, which is determined using the arithmetic average and variance derived from the torque values. Further, these feature vectors are mapped onto a higher dimensional space by using a kernel function. The validity of the proposed method is confirmed by experimental results.

Development of a Sonar Oil Tanker Cargo Measurement System.

DTIC Science & Technology

1980-08-01

used at any one time is dependent upon the capacity of the stripping system. The operation is conducted to strip at least as fast , if not faster, than...operational mode, measure the average value and variance of the thickness of an oil layer on an intermit - tent sampling basis. Laboratory testing

43 CFR 3256.10 - How do I request a variance from BLM requirements that apply to my exploration operations?

Code of Federal Regulations, 2014 CFR

2014-10-01

... Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) GEOTHERMAL RESOURCE LEASING Exploration Operations Relief and Appeals § 3256.10... request must include enough information to explain: (1) Why you cannot comply with the regulatory...

29 CFR 4204.1 - Purpose and scope.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PLANS VARIANCES FOR SALE OF ASSETS General § 4204.1 Purpose and scope. (a) Purpose. Under section 4204 of ERISA, an employer that ceases covered operations under a multiemployer plan, or ceases to have an obligation to contribute for such operations, because of a bona fide, arm's-length sale of assets to an...

RFI in hybrid loops - Simulation and experimental results.

NASA Technical Reports Server (NTRS)

Ziemer, R. E.; Nelson, D. R.; Raghavan, H. R.

1972-01-01

A digital simulation of an imperfect second-order hybrid phase-locked loop (HPLL) operating in radio frequency interference (RFI) is described. Its performance is characterized in terms of phase error variance and phase error probability density function (PDF). Monte-Carlo simulation is used to show that the HPLL can be superior to the conventional phase-locked loops in RFI backgrounds when minimum phase error variance is the goodness criterion. Similar experimentally obtained data are given in support of the simulation data.

Estimates of tropical analysis differences in daily values produced by two operational centers

NASA Technical Reports Server (NTRS)

Kasahara, Akira; Mizzi, Arthur P.

1992-01-01

To assess the uncertainty of daily synoptic analyses for the atmospheric state, the intercomparison of three First GARP Global Experiment level IIIb datasets is performed. Daily values of divergence, vorticity, temperature, static stability, vertical motion, mixing ratio, and diagnosed diabatic heating rate are compared for the period of 26 January-11 February 1979. The spatial variance and mean, temporal mean and variance, 2D wavenumber power spectrum, anomaly correlation, and normalized square difference are employed for comparison.

Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report. October 1 - December 31, 2010.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sisterson, D. L.

2011-02-01

Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near-real time. Raw and processed data are then sent approximately daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the currentmore » year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 - (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the first quarter of FY2010 for the Southern Great Plains (SGP) site is 2097.60 hours (0.95 x 2208 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1987.20 hours (0.90 x 2208) and for the Tropical Western Pacific (TWP) locale is 1876.80 hours (0.85 x 2208). The first ARM Mobile Facility (AMF1) deployment in Graciosa Island, the Azores, Portugal, continued through this quarter, so the OPSMAX time this quarter is 2097.60 hours (0.95 x 2208). The second ARM Mobile Facility (AMF2) began deployment this quarter to Steamboat Springs, Colorado. The experiment officially began November 15, but most of the instruments were up and running by November 1. Therefore, the OPSMAX time for the AMF2 was 1390.80 hours (.95 x 1464 hours) for November and December (61 days). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or datastream. Data availability reported here refers to the average of the individual, continuous datastreams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percentage of data in the Archive represents the average percentage of the time (24 hours per day, 92 days for this quarter) the instruments were operating this quarter. Summary. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for the period October 1-December 31, 2010, for the fixed sites. Because the AMFs operate episodically, the AMF statistics are reported separately and not included in the aggregate average with the fixed sites. This first quarter comprises a total of 2,208 possible hours for the fixed sites and the AMF1 and 1,464 possible hours for the AMF2. The average of the fixed sites exceeded our goal this quarter. The AMF1 has essentially completed its mission and is shutting down to pack up for its next deployment to India. Although all the raw data from the operational instruments are in the Archive for the AMF2, only the processed data are tabulated. Approximately half of the AMF2 instruments have data that was fully processed, resulting in the 46% of all possible data made available to users through the Archive for this first quarter. Typically, raw data is not made available to users unless specifically requested.« less

High variance in reproductive success generates a false signature of a genetic bottleneck in populations of constant size: a simulation study

PubMed Central

2013-01-01

Background Demographic bottlenecks can severely reduce the genetic variation of a population or a species. Establishing whether low genetic variation is caused by a bottleneck or a constantly low effective number of individuals is important to understand a species’ ecology and evolution, and it has implications for conservation management. Recent studies have evaluated the power of several statistical methods developed to identify bottlenecks. However, the false positive rate, i.e. the rate with which a bottleneck signal is misidentified in demographically stable populations, has received little attention. We analyse this type of error (type I) in forward computer simulations of stable populations having greater than Poisson variance in reproductive success (i.e., variance in family sizes). The assumption of Poisson variance underlies bottleneck tests, yet it is commonly violated in species with high fecundity. Results With large variance in reproductive success (Vk ≥ 40, corresponding to a ratio between effective and census size smaller than 0.1), tests based on allele frequencies, allelic sizes, and DNA sequence polymorphisms (heterozygosity excess, M-ratio, and Tajima’s D test) tend to show erroneous signals of a bottleneck. Similarly, strong evidence of population decline is erroneously detected when ancestral and current population sizes are estimated with the model based method MSVAR. Conclusions Our results suggest caution when interpreting the results of bottleneck tests in species showing high variance in reproductive success. Particularly in species with high fecundity, computer simulations are recommended to confirm the occurrence of a population bottleneck. PMID:24131797

Spaceborne receivers: Basic principles

NASA Technical Reports Server (NTRS)

Stacey, J. M.

1984-01-01

The underlying principles of operation of microwave receivers for space observations of planetary surfaces were examined. The design philosophy of the receiver as it is applied to operate functionally as an efficient receiving system, the principle of operation of the key components of the receiver, and the important differences among receiver types are explained. The operating performance and the sensitivity expectations for both the modulated and total power receiver configurations are outlined. The expressions are derived from first principles and are developed through the important intermediate stages to form practicle and easily applied equations. The transfer of thermodynamic energy from point to point within the receiver is illustrated. The language of microwave receivers is applied statistics.

Discrete filtering techniques applied to sequential GPS range measurements

NASA Technical Reports Server (NTRS)

Vangraas, Frank

1987-01-01

The basic navigation solution is described for position and velocity based on range and delta range (Doppler) measurements from NAVSTAR Global Positioning System satellites. The application of discrete filtering techniques is examined to reduce the white noise distortions on the sequential range measurements. A second order (position and velocity states) Kalman filter is implemented to obtain smoothed estimates of range by filtering the dynamics of the signal from each satellite separately. Test results using a simulated GPS receiver show a steady-state noise reduction, the input noise variance divided by the output noise variance, of a factor of four. Recommendations for further noise reduction based on higher order Kalman filters or additional delta range measurements are included.

Solar thermochemical processing system and method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wegeng, Robert S.; Humble, Paul H.; Krishnan, Shankar

A solar thermochemical processing system is disclosed. The system includes a first unit operation for receiving concentrated solar energy. Heat from the solar energy is used to drive the first unit operation. The first unit operation also receives a first set of reactants and produces a first set of products. A second unit operation receives the first set of products from the first unit operation and produces a second set of products. A third unit operation receives heat from the second unit operation to produce a portion of the first set of reactants.

Nonalcoholic fatty liver disease: MR imaging of liver proton density fat fraction to assess hepatic steatosis.

PubMed

Tang, An; Tan, Justin; Sun, Mark; Hamilton, Gavin; Bydder, Mark; Wolfson, Tanya; Gamst, Anthony C; Middleton, Michael; Brunt, Elizabeth M; Loomba, Rohit; Lavine, Joel E; Schwimmer, Jeffrey B; Sirlin, Claude B

2013-05-01

To evaluate the diagnostic performance of magnetic resonance (MR) imaging-estimated proton density fat fraction (PDFF) for assessing hepatic steatosis in nonalcoholic fatty liver disease (NAFLD) by using centrally scored histopathologic validation as the reference standard. This prospectively designed, cross-sectional, internal review board-approved, HIPAA-compliant study was conducted in 77 patients who had NAFLD and liver biopsy. MR imaging-PDFF was estimated from magnitude-based low flip angle multiecho gradient-recalled echo images after T2* correction and multifrequency fat modeling. Histopathologic scoring was obtained by consensus of the Nonalcoholic Steatohepatitis (NASH) Clinical Research Network Pathology Committee. Spearman correlation, additivity and variance stabilization for regression for exploring the effect of a number of potential confounders, and receiver operating characteristic analyses were performed. Liver MR imaging-PDFF was systematically higher, with higher histologic steatosis grade (P < .001), and was significantly correlated with histologic steatosis grade (ρ = 0.69, P < .001). The correlation was not confounded by age, sex, lobular inflammation, hepatocellular ballooning, NASH diagnosis, fibrosis, or magnetic field strength (P = .65). Area under the receiver operating characteristic curves was 0.989 (95% confidence interval: 0.968, 1.000) for distinguishing patients with steatosis grade 0 (n = 5) from those with grade 1 or higher (n = 72), 0.825 (95% confidence interval: 0.734, 0.915) to distinguish those with grade 1 or lower (n = 31) from those with grade 2 or higher (n = 46), and 0.893 (95% confidence interval: 0.809, 0.977) to distinguish those with grade 2 or lower (n = 58) from those with grade 3 (n = 19). MR imaging-PDFF showed promise for assessment of hepatic steatosis grade in patients with NAFLD. For validation, further studies with larger sample sizes are needed. © RSNA, 2013.

CT colonography: influence of 3D viewing and polyp candidate features on interpretation with computer-aided detection.

PubMed

Shi, Rong; Schraedley-Desmond, Pamela; Napel, Sandy; Olcott, Eric W; Jeffrey, R Brooke; Yee, Judy; Zalis, Michael E; Margolis, Daniel; Paik, David S; Sherbondy, Anthony J; Sundaram, Padmavathi; Beaulieu, Christopher F

2006-06-01

To retrospectively determine if three-dimensional (3D) viewing improves radiologists' accuracy in classifying true-positive (TP) and false-positive (FP) polyp candidates identified with computer-aided detection (CAD) and to determine candidate polyp features that are associated with classification accuracy, with known polyps serving as the reference standard. Institutional review board approval and informed consent were obtained; this study was HIPAA compliant. Forty-seven computed tomographic (CT) colonography data sets were obtained in 26 men and 10 women (age range, 42-76 years). Four radiologists classified 705 polyp candidates (53 TP candidates, 652 FP candidates) identified with CAD; initially, only two-dimensional images were used, but these were later supplemented with 3D rendering. Another radiologist unblinded to colonoscopy findings characterized the features of each candidate, assessed colon distention and preparation, and defined the true nature of FP candidates. Receiver operating characteristic curves were used to compare readers' performance, and repeated-measures analysis of variance was used to test features that affect interpretation. Use of 3D viewing improved classification accuracy for three readers and increased the area under the receiver operating characteristic curve to 0.96-0.97 (P<.001). For TP candidates, maximum polyp width (P=.038), polyp height (P=.019), and preparation (P=.004) significantly affected accuracy. For FP candidates, colonic segment (P=.007), attenuation (P<.001), surface smoothness (P<.001), distention (P=.034), preparation (P<.001), and true nature of candidate lesions (P<.001) significantly affected accuracy. Use of 3D viewing increases reader accuracy in the classification of polyp candidates identified with CAD. Polyp size and examination quality are significantly associated with accuracy. Copyright (c) RSNA, 2006.

RE-PERG, a new procedure for electrophysiologic diagnosis of glaucoma that may improve PERG specificity.

PubMed

Mavilio, Alberto; Sisto, Dario; Ferreri, Paolo; Cardascia, Nicola; Alessio, Giovanni

2017-01-01

A significant variability of the second harmonic (2ndH) phase of steady-state pattern electroretinogram (SS-PERG) in intrasession retest has been recently described in glaucoma patients (GP), which has not been found in healthy subjects. To evaluate the reliability of phase variability in retest (a procedure called RE-PERG or REPERG) in the presence of cataract, which is known to affect standard PERG, we tested this procedure in GP, normal controls (NC), and cataract patients (CP). The procedure was performed on 50 GP, 35 NC, and 27 CP. All subjects were examined with RE-PERG and SS-PERG and also with spectral domain optical coherence tomography and standard automated perimetry. Standard deviation of phase and amplitude value of 2ndH were correlated by means of one-way analysis of variance and Pearson correlation, with the mean deviation and pattern standard deviation assessed by standard automated perimetry and retinal nerve fiber layer and the ganglion cell complex thickness assessed by spectral domain optical coherence tomography. Receiver operating characteristics were calculated in cohort populations with and without cataract. Standard deviation of phase of 2ndH was significantly higher in GP with respect to NC ( P <0.001) and CP ( P <0.001), and it correlated with retinal nerve fiber layer ( r =-0.5, P <0.001) and ganglion cell complex ( r =-0.6, P <0.001) defects in GP. Receiver operating characteristic evaluation showed higher specificity of RE-PERG (86.4%; area under the curve 0.93) with respect to SS-PERG (54.5%; area under the curve 0.68) in CP. RE-PERG may improve the specificity of SS-PERG in clinical practice in the discrimination of GP.

5-Aminolevulinic acid-induced protoporphyrin IX fluorescence in meningioma: qualitative and quantitative measurements in vivo.

PubMed

Valdes, Pablo A; Bekelis, Kimon; Harris, Brent T; Wilson, Brian C; Leblond, Frederic; Kim, Anthony; Simmons, Nathan E; Erkmen, Kadir; Paulsen, Keith D; Roberts, David W

2014-03-01

The use of 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence has shown promise as a surgical adjunct for maximizing the extent of surgical resection in gliomas. To date, the clinical utility of 5-ALA in meningiomas is not fully understood, with most descriptive studies using qualitative approaches to 5-ALA-PpIX. To assess the diagnostic performance of 5-ALA-PpIX fluorescence during surgical resection of meningioma. ALA was administered to 15 patients with meningioma undergoing PpIX fluorescence-guided surgery at our institution. At various points during the procedure, the surgeon performed qualitative, visual assessments of fluorescence by using the surgical microscope, followed by a quantitative fluorescence measurement by using an intraoperative probe. Specimens were collected at each point for subsequent neuropathological analysis. Clustered data analysis of variance was used to ascertain a difference between groups, and receiver operating characteristic analyses were performed to assess diagnostic capabilities. Red-pink fluorescence was observed in 80% (12/15) of patients, with visible fluorescence generally demonstrating a strong, homogenous character. Quantitative fluorescence measured diagnostically significant PpIX concentrations (cPpIx) in both visibly and nonvisibly fluorescent tissues, with significantly higher cPpIx in both visibly fluorescent (P < .001) and tumor tissue (P = .002). Receiver operating characteristic analyses also showed diagnostic accuracies up to 90% for differentiating tumor from normal dura. ALA-induced PpIX fluorescence guidance is a potential and promising adjunct in accurately detecting neoplastic tissue during meningioma resective surgery. These results suggest a broader reach for PpIX as a biomarker for meningiomas than was previously noted in the literature.

Surrogate Lipid Markers for Small Dense Low-Density Lipoprotein Particles in Overweight Youth

PubMed Central

Burns, Stephen F.; Lee, So Jung; Arslanian, Silva A.

2013-01-01

Objectives To determine if the ratio of triglycerides to high-density lipoprotein cholesterol (TG/HDL) and non–HDL cholesterol concentration could identify youth with small dense low-density lipoprotein (LDL). Study design One hundred forty-one (75 black and 66 white) overweight adolescents (9 to <18 years) had a fasting measurement of plasma lipids and LDL particle concentrations and size. Receiver operating characteristic curves were used to indicate the ability of different TG/HDL ratios and non–HDL cholesterol concentrations to identify overweight youth with atherogenic LDL concentration and size. Results Youth with a TG/HDL ratio of ≥3 vs <3 had higher concentrations of small dense LDL (1279.5 ± 60.1 vs 841.8 ± 24.2 nmol/L, P < .001) and smaller LDL particle size (20.3 ± 0.1 vs 21.2 ± 0.1 nm, P < .001). In receiver operating characteristic analyses a TG/HDL cut-point of 3 best predicted LDL concentration in white youth, and 2.5 in black youth. Non-HDL cholesterol cut-point of 120 mg/dL and 145 mg/dL predicted LDL particle concentration in white and in black youth, respectively. TG/HDL ratio with body mass index or waist circumference explained 71% and 79% of the variance, respectively, in total small LDL. Conclusions TG/HDL ratio and non-HDL cholesterol can identify overweight youth with atherogenic LDL particles. These easily obtained clinical lipid markers, in combination with body mass index and waist circumference, could be cost effective, in observational or interventional studies, for screening and follow-up of youth at heightened risk for atherogenic LDL. PMID:22809659

Surrogate lipid markers for small dense low-density lipoprotein particles in overweight youth.

PubMed

Burns, Stephen F; Lee, So Jung; Arslanian, Silva A

2012-12-01

To determine if the ratio of triglycerides to high-density lipoprotein cholesterol (TG/HDL) and non-HDL cholesterol concentration could identify youth with small dense low-density lipoprotein (LDL). One hundred forty-one (75 black and 66 white) overweight adolescents (9 to <18 years) had a fasting measurement of plasma lipids and LDL particle concentrations and size. Receiver operating characteristic curves were used to indicate the ability of different TG/HDL ratios and non-HDL cholesterol concentrations to identify overweight youth with atherogenic LDL concentration and size. Youth with a TG/HDL ratio of ≥3 vs <3 had higher concentrations of small dense LDL (1279.5 ± 60.1 vs 841.8 ± 24.2 nmol/L, P < .001) and smaller LDL particle size (20.3 ± 0.1 vs 21.2 ± 0.1 nm, P < .001). In receiver operating characteristic analyses a TG/HDL cut-point of 3 best predicted LDL concentration in white youth, and 2.5 in black youth. Non-HDL cholesterol cut-point of 120 mg/dL and 145 mg/dL predicted LDL particle concentration in white and in black youth, respectively. TG/HDL ratio with body mass index or waist circumference explained 71% and 79% of the variance, respectively, in total small LDL. TG/HDL ratio and non-HDL cholesterol can identify overweight youth with atherogenic LDL particles. These easily obtained clinical lipid markers, in combination with body mass index and waist circumference, could be cost effective, in observational or interventional studies, for screening and follow-up of youth at heightened risk for atherogenic LDL. Copyright © 2012 Mosby, Inc. All rights reserved.

Patient Characteristics and Outcomes in Institutional and Community Long-Term Care.

ERIC Educational Resources Information Center

Braun, Kathryn L.; And Others

1991-01-01

Examined three-way relationships among patient characteristics, type of care (admission to nursing home or community setting), and 6-month outcomes of 352 long-term care patients. Found that patient characteristics influenced type of care received and that substantial portions of variance in outcomes were attributable to initial differences among…

The Disappointing Gift: Dispositional and Situational Moderators of Emotional Expressions

ERIC Educational Resources Information Center

Tobin, Renee M.; Graziano, William G.

2011-01-01

Inferences about emotions in children are limited by studies that rely on only one research method. Convergence across methods provides a stronger basis for inference by identifying method variance. This multimethod study of 116 children (mean age = 8.21 years) examined emotional displays during social exchange. Each child received a desirable…

An Approach To the Study of Patient Suicide During Psychotherapy.

ERIC Educational Resources Information Center

Selkin, James

The 1977 Denver coroner's report found that 45% of all suicide victims received psychotherapy at some time, and 21% were in treatment at the time of death. The literature on suicide places all responsibility upon the therapist. Four major sources of variance deserving consideration, however, are patient variables, therapist variables, treatment…

Postgraduate Student Satisfaction: A Multilevel Analysis of PTES Data

ERIC Educational Resources Information Center

Muijs, Daniel; Bokhove, Christian

2017-01-01

Student satisfaction has received growing attention in Higher Education systems in recent years, and are increasingly used for internal and external accountability in the sector. This does leave us with questions on the extent to which variance in student satisfaction can be explained by Higher Education Institution (HEI) and course attended…

Towards Modifying Children's Ideas about Electric Current.

ERIC Educational Resources Information Center

Osborne, Roger

1983-01-01

Investigated ideas used/favored by 40 California students (ages 8-12) who received little/no formal teaching about electric currents. Also investigated whether they were interested in or could discuss other childrens' ideas and whether they would change their ideas following exposure to experimental evidence that was at variance with these ideas.…

The evolution and consequences of sex-specific reproductive variance.

PubMed

Mullon, Charles; Reuter, Max; Lehmann, Laurent

2014-01-01

Natural selection favors alleles that increase the number of offspring produced by their carriers. But in a world that is inherently uncertain within generations, selection also favors alleles that reduce the variance in the number of offspring produced. If previous studies have established this principle, they have largely ignored fundamental aspects of sexual reproduction and therefore how selection on sex-specific reproductive variance operates. To study the evolution and consequences of sex-specific reproductive variance, we present a population-genetic model of phenotypic evolution in a dioecious population that incorporates previously neglected components of reproductive variance. First, we derive the probability of fixation for mutations that affect male and/or female reproductive phenotypes under sex-specific selection. We find that even in the simplest scenarios, the direction of selection is altered when reproductive variance is taken into account. In particular, previously unaccounted for covariances between the reproductive outputs of different individuals are expected to play a significant role in determining the direction of selection. Then, the probability of fixation is used to develop a stochastic model of joint male and female phenotypic evolution. We find that sex-specific reproductive variance can be responsible for changes in the course of long-term evolution. Finally, the model is applied to an example of parental-care evolution. Overall, our model allows for the evolutionary analysis of social traits in finite and dioecious populations, where interactions can occur within and between sexes under a realistic scenario of reproduction.

The Evolution and Consequences of Sex-Specific Reproductive Variance

PubMed Central

Mullon, Charles; Reuter, Max; Lehmann, Laurent

2014-01-01

Natural selection favors alleles that increase the number of offspring produced by their carriers. But in a world that is inherently uncertain within generations, selection also favors alleles that reduce the variance in the number of offspring produced. If previous studies have established this principle, they have largely ignored fundamental aspects of sexual reproduction and therefore how selection on sex-specific reproductive variance operates. To study the evolution and consequences of sex-specific reproductive variance, we present a population-genetic model of phenotypic evolution in a dioecious population that incorporates previously neglected components of reproductive variance. First, we derive the probability of fixation for mutations that affect male and/or female reproductive phenotypes under sex-specific selection. We find that even in the simplest scenarios, the direction of selection is altered when reproductive variance is taken into account. In particular, previously unaccounted for covariances between the reproductive outputs of different individuals are expected to play a significant role in determining the direction of selection. Then, the probability of fixation is used to develop a stochastic model of joint male and female phenotypic evolution. We find that sex-specific reproductive variance can be responsible for changes in the course of long-term evolution. Finally, the model is applied to an example of parental-care evolution. Overall, our model allows for the evolutionary analysis of social traits in finite and dioecious populations, where interactions can occur within and between sexes under a realistic scenario of reproduction. PMID:24172130

Variance components estimation for continuous and discrete data, with emphasis on cross-classified sampling designs

USGS Publications Warehouse

Gray, Brian R.; Gitzen, Robert A.; Millspaugh, Joshua J.; Cooper, Andrew B.; Licht, Daniel S.

2012-01-01

Variance components may play multiple roles (cf. Cox and Solomon 2003). First, magnitudes and relative magnitudes of the variances of random factors may have important scientific and management value in their own right. For example, variation in levels of invasive vegetation among and within lakes may suggest causal agents that operate at both spatial scales – a finding that may be important for scientific and management reasons. Second, variance components may also be of interest when they affect precision of means and covariate coefficients. For example, variation in the effect of water depth on the probability of aquatic plant presence in a study of multiple lakes may vary by lake. This variation will affect the precision of the average depth-presence association. Third, variance component estimates may be used when designing studies, including monitoring programs. For example, to estimate the numbers of years and of samples per year required to meet long-term monitoring goals, investigators need estimates of within and among-year variances. Other chapters in this volume (Chapters 7, 8, and 10) as well as extensive external literature outline a framework for applying estimates of variance components to the design of monitoring efforts. For example, a series of papers with an ecological monitoring theme examined the relative importance of multiple sources of variation, including variation in means among sites, years, and site-years, for the purposes of temporal trend detection and estimation (Larsen et al. 2004, and references therein).

Femtosecond Photon-Counting Receiver

NASA Technical Reports Server (NTRS)

Krainak, Michael A.; Rambo, Timothy M.; Yang, Guangning; Lu, Wei; Numata, Kenji

2016-01-01

An optical correlation receiver is described that provides ultra-precise distance and/or time/pulse-width measurements even for weak (single photons) and short (femtosecond) optical signals. A new type of optical correlation receiver uses a fourth-order (intensity) interferometer to provide micron distance measurements even for weak (single photons) and short (femtosecond) optical signals. The optical correlator uses a low-noise-integrating detector that can resolve photon number. The correlation (range as a function of path delay) is calculated from the variance of the photon number of the difference of the optical signals on the two detectors. Our preliminary proof-of principle data (using a short-pulse diode laser transmitter) demonstrates tens of microns precision.

Femtosecond Photon-Counting Receiver

NASA Technical Reports Server (NTRS)

Krainak, Michael A.; Rambo, Timothy M.; Yang, Guangning; Lu, Wei; Numata, Kenji

2016-01-01

An optical correlation receiver is described that provides ultra-precise distance and/or time-pulse-width measurements even for weak (single photons) and short (femtosecond) optical signals. A new type of optical correlation receiver uses a fourth-order (intensity) interferometer to provide micron distance measurements even for weak (single photons) and short (femtosecond) optical signals. The optical correlator uses a low-noise-integrating detector that can resolve photon number. The correlation (range as a function of path delay) is calculated from the variance of the photon number of the difference of the optical signals on the two detectors. Our preliminary proof-of principle data (using a short-pulse diode laser transmitter) demonstrates tens of microns precision.

Optimization of electrocoagulation process to treat grey wastewater in batch mode using response surface methodology.

PubMed

Karichappan, Thirugnanasambandham; Venkatachalam, Sivakumar; Jeganathan, Prakash Maran

2014-01-10

Discharge of grey wastewater into the ecological system causes the negative impact effect on receiving water bodies. In this present study, electrocoagulation process (EC) was investigated to treat grey wastewater under different operating conditions such as initial pH (4-8), current density (10-30 mA/cm2), electrode distance (4-6 cm) and electrolysis time (5-25 min) by using stainless steel (SS) anode in batch mode. Four factors with five levels Box-Behnken response surface design (BBD) was employed to optimize and investigate the effect of process variables on the responses such as total solids (TS), chemical oxygen demand (COD) and fecal coliform (FC) removal. The process variables showed significant effect on the electrocoagulation treatment process. The results were analyzed by Pareto analysis of variance (ANOVA) and second order polynomial models were developed in order to study the electrocoagulation process statistically. The optimal operating conditions were found to be: initial pH of 7, current density of 20 mA/cm2, electrode distance of 5 cm and electrolysis time of 20 min. These results indicated that EC process can be scale up in large scale level to treat grey wastewater with high removal efficiency of TS, COD and FC.

Individual strategy ratings improve the control for task difficulty effects in arithmetic problem solving paradigms.

PubMed

Tschentscher, Nadja; Hauk, Olaf

2015-01-01

Mental arithmetic is a powerful paradigm to study problem solving using neuroimaging methods. However, the evaluation of task complexity varies significantly across neuroimaging studies. Most studies have parameterized task complexity by objective features such as the number size. Only a few studies used subjective rating procedures. In fMRI, we provided evidence that strategy self-reports control better for task complexity across arithmetic conditions than objective features (Tschentscher and Hauk, 2014). Here, we analyzed the relative predictive value of self-reported strategies and objective features for performance in addition and multiplication tasks, by using a paradigm designed for neuroimaging research. We found a superiority of strategy ratings as predictor of performance above objective features. In a Principal Component Analysis on reaction times, the first component explained over 90 percent of variance and factor loadings reflected percentages of self-reported strategies well. In multiple regression analyses on reaction times, self-reported strategies performed equally well or better than objective features, depending on the operation type. A Receiver Operating Characteristic (ROC) analysis confirmed this result. Reaction times classified task complexity better when defined by individual ratings. This suggests that participants' strategy ratings are reliable predictors of arithmetic complexity and should be taken into account in neuroimaging research.

Individual strategy ratings improve the control for task difficulty effects in arithmetic problem solving paradigms

PubMed Central

Tschentscher, Nadja; Hauk, Olaf

2015-01-01

Mental arithmetic is a powerful paradigm to study problem solving using neuroimaging methods. However, the evaluation of task complexity varies significantly across neuroimaging studies. Most studies have parameterized task complexity by objective features such as the number size. Only a few studies used subjective rating procedures. In fMRI, we provided evidence that strategy self-reports control better for task complexity across arithmetic conditions than objective features (Tschentscher and Hauk, 2014). Here, we analyzed the relative predictive value of self-reported strategies and objective features for performance in addition and multiplication tasks, by using a paradigm designed for neuroimaging research. We found a superiority of strategy ratings as predictor of performance above objective features. In a Principal Component Analysis on reaction times, the first component explained over 90 percent of variance and factor loadings reflected percentages of self-reported strategies well. In multiple regression analyses on reaction times, self-reported strategies performed equally well or better than objective features, depending on the operation type. A Receiver Operating Characteristic (ROC) analysis confirmed this result. Reaction times classified task complexity better when defined by individual ratings. This suggests that participants’ strategy ratings are reliable predictors of arithmetic complexity and should be taken into account in neuroimaging research. PMID:26321997

Computationally robust and noise resistant numerical detector for the detection of atmospheric infrasound.

PubMed

Lee, Dong-Chang; Olson, John V; Szuberla, Curt A L

2013-07-01

This work reports on a performance study of two numerical detectors that are particularly useful for infrasound arrays operating under windy conditions. The sum of squares of variance ratios (SSVR1)-proposed for detecting signals with frequency ranging from 1 to 10 Hz-is computed by taking the ratio of the squared sum of eigenvalues to the square of largest eigenvalue of the covariance matrix of the power spectrum. For signals with lower frequency between 0.015 and 0.1 Hz, SSVR2 is developed to reduce the detector's sensitivity to noise. The detectors' performances are graphically compared against the current method, the mean of cross correlation maxima (MCCM), using the receiver operating characteristics curves and three types of atmospheric infrasound, corrupted by Gaussian and Pink noise. The MCCM and SSVR2 detectors were also used to detect microbaroms from the 24 h-long infrasound data. It was found that the two detectors outperform the MCCM detector in both sensitivity and computational efficiency. For mine blasts corrupted by Pink noise (signal-to-noise ratio = -7 dB), the MCCM and SSVR1 detectors yield 62 and 88 % true positives when accepting 20% false positives. For an eight-sensor array, the speed gain is approximately eleven-fold for a 50 s long signal.

Antihypertensive Effects of Hydroalcoholic Extract of Crataegus Azarolus Subspecies Aronia Fruit in Rats with Renovascular Hypertension: An Experimental Mechanistic Study

PubMed Central

Haydari, Mohammad Reza; Panjeshahin, Mohammad Reza; Mashghoolozekr, Elaheh; Nekooeian, Ali Akbar

2017-01-01

Background: Hawthorn species decreases blood pressure and relaxes precontracted vessels. This study aimed at examining the antihypertensive effect and related mechanisms of hydroalcoholic extract of Crataegus azarolus subspecies aronia fruit in rats with renovascular hypertension. Methods: Six groups of male Sprague-Dawley rats, each containing 6 to 8 rats, were studied. The groups comprised of one sham group and 5 renal artery-clipped groups. The sham group received vehicle (distilled water 0.5 ml/day) and the renal artery-clipped groups received vehicle or the extract at 5, 10, 20 or 30 mg/kg/day. Oral vehicle or extract was administered daily for 4 weeks following sham-operation or induction of hypertension. Systolic blood pressure and heart rate were measured weekly. Isolated aorta study was performed by last week and serum superoxide dismutase and glutathione reductase were measured. The findings were analyzed using one-way analysis of variance and Duncan’s multiple range tests at P≤0.05 using SigmaStat software. Results: The data obtained after 4 weeks of treatment showed that the renal artery-clipped group receiving vehicle had significantly higher systolic blood pressure (P=0.002) and phenylephrine maximal response (P=0.01); and lower acetylcholine maximal response (P=0.01), serum superoxide dismutase (P=0.006) and serum glutathione reductase (P=0.006) than those of the sham group. The renal artery-clipped group receiving extract had significantly lower systolic blood pressure (P=0.03) and phenylephrine maximal response (P=0.01); and significantly higher acetylcholine maximal response (P=0.01), serum superoxide dismutase (P=0.015), and serum glutathione reductase (P=0.015) than those of the renal artery-clipped group receiving vehicle. Conclusion: Our findings show that the hydroalcoholic extract of Crataegus azarolus subspecies aronia fruit has antihypertensive effects, which may be partly due to antioxidant and nitric oxide releasing effects. PMID:28533575

Antihypertensive Effects of Hydroalcoholic Extract of Crataegus Azarolus Subspecies Aronia Fruit in Rats with Renovascular Hypertension: An Experimental Mechanistic Study.

PubMed

Haydari, Mohammad Reza; Panjeshahin, Mohammad Reza; Mashghoolozekr, Elaheh; Nekooeian, Ali Akbar

2017-05-01

Hawthorn species decreases blood pressure and relaxes precontracted vessels. This study aimed at examining the antihypertensive effect and related mechanisms of hydroalcoholic extract of Crataegus azarolus subspecies aronia fruit in rats with renovascular hypertension. Six groups of male Sprague-Dawley rats, each containing 6 to 8 rats, were studied. The groups comprised of one sham group and 5 renal artery-clipped groups. The sham group received vehicle (distilled water 0.5 ml/day) and the renal artery-clipped groups received vehicle or the extract at 5, 10, 20 or 30 mg/kg/day. Oral vehicle or extract was administered daily for 4 weeks following sham-operation or induction of hypertension. Systolic blood pressure and heart rate were measured weekly. Isolated aorta study was performed by last week and serum superoxide dismutase and glutathione reductase were measured. The findings were analyzed using one-way analysis of variance and Duncan's multiple range tests at P≤0.05 using SigmaStat software. The data obtained after 4 weeks of treatment showed that the renal artery-clipped group receiving vehicle had significantly higher systolic blood pressure (P=0.002) and phenylephrine maximal response (P=0.01); and lower acetylcholine maximal response (P=0.01), serum superoxide dismutase (P=0.006) and serum glutathione reductase (P=0.006) than those of the sham group. The renal artery-clipped group receiving extract had significantly lower systolic blood pressure (P=0.03) and phenylephrine maximal response (P=0.01); and significantly higher acetylcholine maximal response (P=0.01), serum superoxide dismutase (P=0.015), and serum glutathione reductase (P=0.015) than those of the renal artery-clipped group receiving vehicle. Our findings show that the hydroalcoholic extract of Crataegus azarolus subspecies aronia fruit has antihypertensive effects, which may be partly due to antioxidant and nitric oxide releasing effects.

Predictability Experiments With the Navy Operational Global Atmospheric Prediction System

NASA Astrophysics Data System (ADS)

Reynolds, C. A.; Gelaro, R.; Rosmond, T. E.

2003-12-01

There are several areas of research in numerical weather prediction and atmospheric predictability, such as targeted observations and ensemble perturbation generation, where it is desirable to combine information about the uncertainty of the initial state with information about potential rapid perturbation growth. Singular vectors (SVs) provide a framework to accomplish this task in a mathematically rigorous and computationally feasible manner. In this study, SVs are calculated using the tangent and adjoint models of the Navy Operational Global Atmospheric Prediction System (NOGAPS). The analysis error variance information produced by the NRL Atmospheric Variational Data Assimilation System is used as the initial-time SV norm. These VAR SVs are compared to SVs for which total energy is both the initial and final time norms (TE SVs). The incorporation of analysis error variance information has a significant impact on the structure and location of the SVs. This in turn has a significant impact on targeted observing applications. The utility and implications of such experiments in assessing the analysis error variance estimates will be explored. Computing support has been provided by the Department of Defense High Performance Computing Center at the Naval Oceanographic Office Major Shared Resource Center at Stennis, Mississippi.

Workflow for Criticality Assessment Applied in Biopharmaceutical Process Validation Stage 1.

PubMed

Zahel, Thomas; Marschall, Lukas; Abad, Sandra; Vasilieva, Elena; Maurer, Daniel; Mueller, Eric M; Murphy, Patrick; Natschläger, Thomas; Brocard, Cécile; Reinisch, Daniela; Sagmeister, Patrick; Herwig, Christoph

2017-10-12

Identification of critical process parameters that impact product quality is a central task during regulatory requested process validation. Commonly, this is done via design of experiments and identification of parameters significantly impacting product quality (rejection of the null hypothesis that the effect equals 0). However, parameters which show a large uncertainty and might result in an undesirable product quality limit critical to the product, may be missed. This might occur during the evaluation of experiments since residual/un-modelled variance in the experiments is larger than expected a priori. Estimation of such a risk is the task of the presented novel retrospective power analysis permutation test. This is evaluated using a data set for two unit operations established during characterization of a biopharmaceutical process in industry. The results show that, for one unit operation, the observed variance in the experiments is much larger than expected a priori, resulting in low power levels for all non-significant parameters. Moreover, we present a workflow of how to mitigate the risk associated with overlooked parameter effects. This enables a statistically sound identification of critical process parameters. The developed workflow will substantially support industry in delivering constant product quality, reduce process variance and increase patient safety.

Team communication during patient handover from the operating room: more than facts and figures.

PubMed

Manser, Tanja; Foster, Simon; Flin, Rhona; Patey, Rona

2013-02-01

This study was aimed at examining team communication during postoperative handover and its relationship to clinicians' self-ratings of handover quality. Adverse events can often be traced back to inadequate communication during patient handover. Research and improvement efforts have mostly focused on the information transfer function of patient handover. However, the specific mechanisms between handover communication processes among teams of transferring and receiving clinicians and handover quality are poorly understood. We conducted a prospective, cross-sectional observation study using a taxonomy for handover behaviors developed on the basis of established approaches for analyzing teamwork in health care. Immediately after the observation, transferring and receiving clinicians rated the quality of the handover using a structured tool for handover quality assessment. Handover communication during 117 handovers in three postoperative settings and its relationship to clinicians' self-ratings of handover quality were analyzed with the use of correlation analyses and analyses of variance. We identified significantly different patterns of handover communication between clinical settings and across handover roles. Assessments provided during handover were related to higher ratings of handover quality overall and to all four dimensions of handover quality identified in this study. If assessment was lacking, we observed compensatory information seeking by the receiving team. Handover quality is more than the correct, complete transmission of patient information. Assessments, including predictions or anticipated problems, are critical to the quality of postoperative handover. The identification of communication behaviors related to high-quality handovers is necessary to effectively support the design and evaluation of handover improvement efforts.

The Pattern Across the Continental United States of Evapotranspiration Variability Associated with Water Availability

NASA Technical Reports Server (NTRS)

Koster, Randal D.; Salvucci, Guido D.; Rigden, Angela J.; Jung, Martin; Collatz, G. James; Schubert, Siegfried D.

2015-01-01

The spatial pattern across the continental United States of the interannual variance of warm season water-dependent evapotranspiration, a pattern of relevance to land-atmosphere feedback, cannot be measured directly. Alternative and indirect approaches to estimating the pattern, however, do exist, and given the uncertainty of each, we use several such approaches here. We first quantify the water dependent evapotranspiration variance pattern inherent in two derived evapotranspiration datasets available from the literature. We then search for the pattern in proxy geophysical variables (air temperature, stream flow, and NDVI) known to have strong ties to evapotranspiration. The variances inherent in all of the different (and mostly independent) data sources show some differences but are generally strongly consistent they all show a large variance signal down the center of the U.S., with lower variances toward the east and (for the most part) toward the west. The robustness of the pattern across the datasets suggests that it indeed represents the pattern operating in nature. Using Budykos hydroclimatic framework, we show that the pattern can largely be explained by the relative strength of water and energy controls on evapotranspiration across the continent.

Candidate Evaluation Using Targeted Construct Assessment in the Multiple Mini-Interview: A Multifaceted Rasch Model Analysis.

PubMed

McLaughlin, Jacqueline E; Singer, David; Cox, Wendy C

2017-01-01

Construct: A 7-station multiple mini-interview (MMI) circuit was implemented and assessed for 214 candidates rated by 37 interviewers (N = 1,498 ratings). The MMI stations were designed to assess 6 specific constructs (adaptability, empathy, integrity, critical thinking, teamwork [receiving instruction], teamwork [giving instruction]) and one open station about the candidate's interest in the school. Despite the apparent benefits of the MMI, construct-irrelevant variance continues to be a topic of study. Refining the MMI to more effectively measure candidate ability is critical to improving our ability to identify and select candidates that are equipped for success within health professions education and the workforce. Each station assessed a single construct and was rated by a single interviewer who was provided only the name of the candidate and no additional information about the candidate's background, application, or prior academic performance. All interviewers received online and in-person training in the fall prior to the MMI and the morning of the MMI. A 3-facet multifaceted Rasch measurement analysis was completed to determine interviewer severity, candidate ability, and MMI station difficulty and examine how the model performed overall (e.g., rating scale). Altogether, the Rasch measures explained 62.84% of the variance in the ratings. Differences in candidate ability explained 45.28% of the variance in the data, whereas differences in interviewer severity explained 16.09% of the variance in the data. None of the interviewers had Infit or Outfit mean-square scores greater than 1.7, and only 2 (5.4%) had mean-square scores less than 0.5. The data demonstrated acceptable fit to the multifaceted Rasch measurement model. This work is the first of its kind in pharmacy and provides insight into the development of an MMI that provides useful and meaningful candidate assessment ratings for institutional decision making.

Using convolutional decoding to improve time delay and phase estimation in digital communications

DOEpatents

Ormesher, Richard C [Albuquerque, NM; Mason, John J [Albuquerque, NM

2010-01-26

The time delay and/or phase of a communication signal received by a digital communication receiver can be estimated based on a convolutional decoding operation that the communication receiver performs on the received communication signal. If the original transmitted communication signal has been spread according to a spreading operation, a corresponding despreading operation can be integrated into the convolutional decoding operation.

Fulfilment of knowledge expectations and emotional state among people undergoing hip replacement: a multi-national survey.

PubMed

Johansson Stark, Asa; Ingadottir, Brynja; Salanterä, Sanna; Sigurdardottir, Arun; Valkeapää, Kirsi; Bachrach-Lindström, Margareta; Unosson, Mitra

2014-11-01

Patient education in connection with hip replacement is intended to prepare patients for surgery, discharge and postoperative recovery. Patients experience symptoms and emotions due to disease or upcoming surgery which can affect how their knowledge expectations are fulfilled. To describe the differences between received and expected knowledge in patients undergoing elective hip replacement in three Nordic countries, and to analyse how these differences are related to patients' characteristics, preoperative symptoms and emotions. A descriptive, prospective survey with two data collection points; before admission and at hospital discharge after surgery. Two Finnish, three Icelandic and two Swedish hospitals. The population consisted of patients on a waiting list for hip replacement. Of the consecutively included patients, 320 answered questionnaires both before admission and at discharge and were included in the study. The mean age of the patients was 64 years, and 55% were women. Structured questionnaires were used; the knowledge expectations of hospital patients scale and self-reported scales for symptoms and emotions before admission and received knowledge of hospital patients scale at discharge. Fulfilment of knowledge expectation was assessed by calculating the difference between received and expected knowledge with a paired sample t-test. A multiple stepwise regression model was used to explain the variance of fulfilled knowledge expectations. Patients expected more knowledge than they received (p<0.001) and 77% of them had unfulfilled knowledge expectations. Patients with a higher level of education were more likely to have unfulfilled knowledge expectations. A higher level of education was also related to a greater difference between received and expected knowledge. The difference was more correlated with patients' emotions than their symptoms. A depressive state was the major predictor of the variance in the difference between received and expected knowledge. In order to better support patients by education it is necessary to assess their emotional state, educational level and knowledge expectations before surgery. Copyright © 2014 Elsevier Ltd. All rights reserved.

Split-mouth comparison of the accuracy of computer-generated and conventional surgical guides.

PubMed

Farley, Nathaniel E; Kennedy, Kelly; McGlumphy, Edwin A; Clelland, Nancy L

2013-01-01

Recent clinical studies have shown that implant placement is highly predictable with computer-generated surgical guides; however, the reliability of these guides has not been compared to that of conventional guides clinically. This study aimed to compare the accuracy of reproducing planned implant positions with computer-generated and conventional surgical guides using a split-mouth design. Ten patients received two implants each in symmetric locations. All implants were planned virtually using a software program and information from cone beam computed tomographic scans taken with scan appliances in place. Patients were randomly selected for computer-aided design/computer-assisted manufacture (CAD/CAM)-guided implant placement on their right or left side. Conventional guides were used on the contralateral side. Patients underwent operative cone beam computed tomography postoperatively. Planned and actual implant positions were compared using three-dimensional analyses capable of measuring volume overlap as well as differences in angles and coronal and apical positions. Results were compared using a mixed-model repeated-measures analysis of variance and were further analyzed using a Bartlett test for unequal variance (α = .05). Implants placed with CAD/CAM guides were closer to the planned positions in all eight categories examined. However, statistically significant differences were shown only for coronal horizontal distances. It was also shown that CAD/CAM guides had less variability than conventional guides, which was statistically significant for apical distance. Implants placed using CAD/CAM surgical guides provided greater accuracy in a lateral direction than conventional guides. In addition, CAD/CAM guides were more consistent in their deviation from the planned locations than conventional guides.

Relations between a novel, reliable, and rapid index of arterial compliance (PP-HDI) and well-established inidices of arterial blood pressure (ABP) in a sample of hypertensive elderly subjects.

PubMed

Bergamini, L; Finelli, M E; Bendini, C; Ferrari, E; Veschi, M; Neviani, F; Manni, B; Pelosi, A; Rioli, G; Neri, M

2009-01-01

Hypertension is a risk factor for a long-lasting arterial wall-remodelling leading to stiffness. The rapid method measuring the pulse pressure (PP) by means of the tool of Hypertension Diagnostic Instruments (HDI) called PP-HDI, overcomes some of the problems arising with more-time consuming methods, like ambulatory blood pressure monitoring (ABPM), and give information about the elasticity of the arterial walls. We studied the relationship between the PP-HDI, the large artery compliance (LA-C) and small artery compliance (SA-C) and few well-established indices of arterial blood pressure (ABP) in a sample of 75 hypertensive subjects, aged 65 years and over. Significant correlations between LA-C and heart rate (HR), PP-ABPM and PP-HDI were found. SA-C relates with HR and systolic blood pressure (SBP) measured in lying and standing positions. Applying a stepwise regression analysis, we found that LA-C variance stems from PP-HDI and HR, while SA-C variance stems from SBP in lying position. Receiver operator characteristic (ROC) curves for thresholds of PP showed that PP-HDI reached levels of sensitivity/specificity similar to PP-ABPM. In conclusion, surveillance of ABP through hemo-dynamic indices, in particular of SBP, is essential, nevertheless the advantage of this control is not known in an elderly population where the organ damage is already evident. PP needs necessarily an instrumental measurement. The PP-HDI result is similar in reliability with respect to PPABPM, but is more rapid and well applicable in an elderly population.

30 CFR 933.700 - North Carolina Federal program.

Code of Federal Regulations, 2011 CFR

2011-07-01

... INTERIOR PROGRAMS FOR THE CONDUCT OF SURFACE MINING OPERATIONS WITHIN EACH STATE NORTH CAROLINA § 933.700... that: (1) Such variance is necessary because of the unique nature of North Carolina's terrain, climate...

30 CFR 933.700 - North Carolina Federal program.

Code of Federal Regulations, 2013 CFR

2013-07-01

... INTERIOR PROGRAMS FOR THE CONDUCT OF SURFACE MINING OPERATIONS WITHIN EACH STATE NORTH CAROLINA § 933.700... that: (1) Such variance is necessary because of the unique nature of North Carolina's terrain, climate...

30 CFR 933.700 - North Carolina Federal program.

Code of Federal Regulations, 2012 CFR

2012-07-01

... INTERIOR PROGRAMS FOR THE CONDUCT OF SURFACE MINING OPERATIONS WITHIN EACH STATE NORTH CAROLINA § 933.700... that: (1) Such variance is necessary because of the unique nature of North Carolina's terrain, climate...

30 CFR 933.700 - North Carolina Federal program.

Code of Federal Regulations, 2014 CFR

2014-07-01

... INTERIOR PROGRAMS FOR THE CONDUCT OF SURFACE MINING OPERATIONS WITHIN EACH STATE NORTH CAROLINA § 933.700... that: (1) Such variance is necessary because of the unique nature of North Carolina's terrain, climate...

Spacecraft methods and structures with enhanced attitude control that facilitates gyroscope substitutions

NASA Technical Reports Server (NTRS)

Li, Rongsheng (Inventor); Kurland, Jeffrey A. (Inventor); Dawson, Alec M. (Inventor); Wu, Yeong-Wei A. (Inventor); Uetrecht, David S. (Inventor)

2004-01-01

Methods and structures are provided that enhance attitude control during gyroscope substitutions by insuring that a spacecraft's attitude control system does not drive its absolute-attitude sensors out of their capture ranges. In a method embodiment, an operational process-noise covariance Q of a Kalman filter is temporarily replaced with a substantially greater interim process-noise covariance Q. This replacement increases the weight given to the most recent attitude measurements and hastens the reduction of attitude errors and gyroscope bias errors. The error effect of the substituted gyroscopes is reduced and the absolute-attitude sensors are not driven out of their capture range. In another method embodiment, this replacement is preceded by the temporary replacement of an operational measurement-noise variance R with a substantially larger interim measurement-noise variance R to reduce transients during the gyroscope substitutions.

Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 – September 30, 2008

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sisterson, DL

2008-09-30

Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month formore » the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 – (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the fourth quarter of FY 2008 for the Southern Great Plains (SGP) site is 2,097.60 hours (0.95 x 2,208 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,987.20 hours (0.90 x 2,208), and for the Tropical Western Pacific (TWP) locale is 1,876.80 hours (0.85 x 2,208). The OPSMAX time for the ARM Mobile Facility (AMF) is not reported this quarter because the data have not yet been released from China to the DMF for processing. The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percentage of data in the Archive represents the average percentage of the time (24 hours per day, 92 days for this quarter) the instruments were operating this quarter.« less

Valuing hydrological forecasts for a pumped storage assisted hydro facility

NASA Astrophysics Data System (ADS)

Zhao, Guangzhi; Davison, Matt

2009-07-01

SummaryThis paper estimates the value of a perfectly accurate short-term hydrological forecast to the operator of a hydro electricity generating facility which can sell its power at time varying but predictable prices. The expected value of a less accurate forecast will be smaller. We assume a simple random model for water inflows and that the costs of operating the facility, including water charges, will be the same whether or not its operator has inflow forecasts. Thus, the improvement in value from better hydrological prediction results from the increased ability of the forecast using facility to sell its power at high prices. The value of the forecast is therefore the difference between the sales of a facility operated over some time horizon with a perfect forecast, and the sales of a similar facility operated over the same time horizon with similar water inflows which, though governed by the same random model, cannot be forecast. This paper shows that the value of the forecast is an increasing function of the inflow process variance and quantifies how much the value of this perfect forecast increases with the variance of the water inflow process. Because the lifetime of hydroelectric facilities is long, the small increase observed here can lead to an increase in the profitability of hydropower investments.

Clinical results of an organ procurement organization effort to increase utilization of donors after cardiac death.

PubMed

Whiting, James F; Delmonico, Francis; Morrissey, Paul; Basadonna, Giacomo; Johnson, Scott; Lewis, W David; Rohrer, Richard; O'Connor, Kevin; Bradley, James; Lovewell, Tammy D; Lipkowitz, George

2006-05-27

To stimulate organ donation, an organ procurement organization (OPO)-wide effort was undertaken to increase donors after cardiac death (DCD) over a 5-year period. This included commonality of protocols, pulsatile perfusion of kidneys, centralization of data and a regional allocation variance designed to minimize cold ischemia times and encourage adoption of DCD protocols at transplant centers. In one OPO, eight centers initiated DCD programs in 11 hospitals. A total of 52 DCD donors were procured, increasing from four in 1999 to 21 in 2003. Eleven donors had care withdrawn in the operating room, whereas 41 had care withdrawn in the ICU. In all, 91 patients received renal transplants from these 52 donors (12 kidneys discarded, one double transplant), whereas 5 patients received liver transplants. One-, two-, and three-year kidney graft survival rates were 90%, 90%, and 82%, respectively. Fifty-five percent of patients needed at least one session of hemodialysis postoperatively. Mean recipient hospital length of stay was 11.1+/-6 days. Mean creatinine levels at 3, 6, 12, and 24 months were 1.65, 1.40, 1.41, and 1.40, respectively. DCD donors can be an important source of donor organs and provide excellent overall outcomes. Regional cooperation and a prospectively considered allocation and distribution system are important considerations in stimulating DCD programs.

Preliminary genomic predictions of feed saved for 1.4 million Holsteins

USDA-ARS?s Scientific Manuscript database

Genomic predictions of transmitting ability (GPTAs) for residual feed intake (RFI) were computed using data from 4,621 42-day and 202 28-day feed intake trials of 3,947 U.S. Holsteins born 1999-2013 in 9 research herds. The 28-day records had 8.5% larger error variance than 42-day records and receiv...

29 CFR 4204.11 - Variance of the bond/escrow and sale-contract requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... determining the purchaser's average net income after taxes under § 4204.13(a)(1), for any year included in the... financial statements for the specified time period. (d) Limited exemption during pendency of request...) within 30 days after the date on which it receives notice of the plan's decision. (e) Method and date of...

Estimating acreage by double sampling using LANDSAT data

NASA Technical Reports Server (NTRS)

Pont, F.; Horwitz, H.; Kauth, R. (Principal Investigator)

1982-01-01

Double sampling techniques employing LANDSAT data for estimating the acreage of corn and soybeans was investigated and evaluated. The evaluation was based on estimated costs and correlations between two existing procedures having differing cost/variance characteristics, and included consideration of their individual merits when coupled with a fictional 'perfect' procedure of zero bias and variance. Two features of the analysis are: (1) the simultaneous estimation of two or more crops; and (2) the imposition of linear cost constraints among two or more types of resource. A reasonably realistic operational scenario was postulated. The costs were estimated from current experience with the measurement procedures involved, and the correlations were estimated from a set of 39 LACIE-type sample segments located in the U.S. Corn Belt. For a fixed variance of the estimate, double sampling with the two existing LANDSAT measurement procedures can result in a 25% or 50% cost reduction. Double sampling which included the fictional perfect procedure results in a more cost effective combination when it is used with the lower cost/higher variance representative of the existing procedures.

Parametric estimates for the receiver operating characteristic curve generalization for non-monotone relationships.

PubMed

Martínez-Camblor, Pablo; Pardo-Fernández, Juan C

2017-01-01

Diagnostic procedures are based on establishing certain conditions and then checking if those conditions are satisfied by a given individual. When the diagnostic procedure is based on a continuous marker, this is equivalent to fix a region or classification subset and then check if the observed value of the marker belongs to that region. Receiver operating characteristic curve is a valuable and popular tool to study and compare the diagnostic ability of a given marker. Besides, the area under the receiver operating characteristic curve is frequently used as an index of the global discrimination ability. This paper revises and widens the scope of the receiver operating characteristic curve definition by setting the classification subsets in which the final decision is based in the spotlight of the analysis. We revise the definition of the receiver operating characteristic curve in terms of particular classes of classification subsets and then focus on a receiver operating characteristic curve generalization for situations in which both low and high values of the marker are associated with more probability of having the studied characteristic. Parametric and non-parametric estimators of the receiver operating characteristic curve generalization are investigated. Monte Carlo studies and real data examples illustrate their practical performance.

Reducing elective general surgery cancellations at a Canadian hospital

PubMed Central

Azari-Rad, Solmaz; Yontef, Alanna L.; Aleman, Dionne M.; Urbach, David R.

2013-01-01

Background In Canadian hospitals, which are typically financed by global annual budgets, overuse of operating rooms is a financial risk that is frequently managed by cancelling elective surgical procedures. It is uncertain how different scheduling rules affect the rate of elective surgery cancellations. Methods We used discrete event simulation modelling to represent perioperative processes at a hospital in Toronto, Canada. We tested the effects of the following 3 scenarios on the number of surgical cancellations: scheduling surgeons’ operating days based on their patients’ average length of stay in hospital, sequencing surgical procedures by average duration and variance, and increasing the number of post-surgical ward beds. Results The number of elective cancellations was reduced by scheduling surgeons whose patients had shorter average lengths of stay in hospital earlier in the week, sequencing shorter surgeries and those with less variance in duration earlier in the day, and by adding up to 2 additional beds to the postsurgical ward. Conclusion Discrete event simulation modelling can be used to develop strategies for improving efficiency in operating rooms. PMID:23351498

Pilot Study to Evaluate the Effect of Topical Dimethicone on Clinical Signs and Skin Barrier Function in Dogs with Naturally Occurring Atopic Dermatitis

PubMed Central

Pellicoro, C.; Marsella, R.; Ahrens, K.

2013-01-01

This study investigated the effects of a skin protectant solution (dimethicone 2%) on clinical signs and skin barrier function in canine atopic dermatitis (AD). Eighteen dogs with AD were randomly divided into two groups, one received dimethicone and the other received the vehicle (cyclomethicone) on selected areas (pinnae, groin, and axillae) daily for 4 weeks. Owners and investigators were blinded regarding group allocation. Clinical efficacy was evaluated using a scoring system and skin barrier by measuring the transepidermal water loss. Twelve dogs completed the study (50% drop rate in the vehicle and 20% in the dimethicone). For clinical signs, analysis of variance showed an effect of time (P < 0.005; day 0 > day 28) and region (axillae < groin < pinnae) but no effect of group or group × time interaction. For transepidermal water loss, analysis of variance showed only a main effect of region (axillae > pinnae > groin). Pearson found no correlation between transepidermal water loss and clinical scores. In this pilot study dimethicone had no significant effect on clinical signs and transepidermal water loss in canine atopic dermatitis. PMID:23710417

Smooth time-dependent receiver operating characteristic curve estimators.

PubMed

Martínez-Camblor, Pablo; Pardo-Fernández, Juan Carlos

2018-03-01

The receiver operating characteristic curve is a popular graphical method often used to study the diagnostic capacity of continuous (bio)markers. When the considered outcome is a time-dependent variable, two main extensions have been proposed: the cumulative/dynamic receiver operating characteristic curve and the incident/dynamic receiver operating characteristic curve. In both cases, the main problem for developing appropriate estimators is the estimation of the joint distribution of the variables time-to-event and marker. As usual, different approximations lead to different estimators. In this article, the authors explore the use of a bivariate kernel density estimator which accounts for censored observations in the sample and produces smooth estimators of the time-dependent receiver operating characteristic curves. The performance of the resulting cumulative/dynamic and incident/dynamic receiver operating characteristic curves is studied by means of Monte Carlo simulations. Additionally, the influence of the choice of the required smoothing parameters is explored. Finally, two real-applications are considered. An R package is also provided as a complement to this article.

Feasibility of a Clinical Pathway with Early Oral Intake and Discharge for Laparoscopic Gastrectomy.

PubMed

Nakagawa, M; Tomii, C; Inokuchi, M; Otsuki, S; Kojima, K

2017-12-01

Although some studies have reported the safety of early oral intake after gastrectomy, it still remains controversial. This study focused on the feasibility of a clinical pathway with early oral intake and discharge setting for exclusively laparoscopic distal gastrectomy. A clinical pathway was applied to 403 patients until December 2014. In the protocol, patients are allowed to take a sip of water and a soft diet on the first and second days after the operation, respectively, and the discharge day is set as the fifth to seventh day after the operation. Clinicopathological variables were prospectively collected, and risk factors for discharge variances were analyzed. The completion rate of the clinical pathway was 76.9%. There were five re-admissions (1.2%). The overall morbidity rate was 18% ( n = 72), and major complications (Clavien-Dindo IIIa or greater) occurred in 13 patients (3%). Complications were the causes for discharge variances in 68 cases (73%), while the attending surgeons' judgment was the cause in 25 cases (27%). On multivariate analysis, age (odds ratio = 2.23, 95% confidence interval = 1.38-3.60, p = 0.001) and operative time (odds ratio = 2.38, 95% confidence interval = 1.45-3.98, p = 0.001) were independent risk factors for discharge variances. A high completion rate of a clinical pathway with early oral intake and discharge setting for laparoscopic distal gastrectomy was achievable with an acceptably low re-admission rate. Laparoscopic distal gastrectomy is recommended as a first step for a clinical pathway with an early oral intake and discharge protocol.

Performance of correlation receivers in the presence of impulse noise.

NASA Technical Reports Server (NTRS)

Moore, J. D.; Houts, R. C.

1972-01-01

An impulse noise model, which assumes that each noise burst contains a randomly weighted version of a basic waveform, is used to derive the performance equations for a correlation receiver. The expected number of bit errors per noise burst is expressed as a function of the average signal energy, signal-set correlation coefficient, bit time, noise-weighting-factor variance and probability density function, and a time range function which depends on the crosscorrelation of the signal-set basis functions and the noise waveform. Unlike the performance results for additive white Gaussian noise, it is shown that the error performance for impulse noise is affected by the choice of signal-set basis function, and that Orthogonal signaling is not equivalent to On-Off signaling with the same average energy. Furthermore, it is demonstrated that the correlation-receiver error performance can be improved by inserting a properly specified nonlinear device prior to the receiver input.

Blinded sample size re-estimation in three-arm trials with 'gold standard' design.

PubMed

Mütze, Tobias; Friede, Tim

2017-10-15

In this article, we study blinded sample size re-estimation in the 'gold standard' design with internal pilot study for normally distributed outcomes. The 'gold standard' design is a three-arm clinical trial design that includes an active and a placebo control in addition to an experimental treatment. We focus on the absolute margin approach to hypothesis testing in three-arm trials at which the non-inferiority of the experimental treatment and the assay sensitivity are assessed by pairwise comparisons. We compare several blinded sample size re-estimation procedures in a simulation study assessing operating characteristics including power and type I error. We find that sample size re-estimation based on the popular one-sample variance estimator results in overpowered trials. Moreover, sample size re-estimation based on unbiased variance estimators such as the Xing-Ganju variance estimator results in underpowered trials, as it is expected because an overestimation of the variance and thus the sample size is in general required for the re-estimation procedure to eventually meet the target power. To overcome this problem, we propose an inflation factor for the sample size re-estimation with the Xing-Ganju variance estimator and show that this approach results in adequately powered trials. Because of favorable features of the Xing-Ganju variance estimator such as unbiasedness and a distribution independent of the group means, the inflation factor does not depend on the nuisance parameter and, therefore, can be calculated prior to a trial. Moreover, we prove that the sample size re-estimation based on the Xing-Ganju variance estimator does not bias the effect estimate. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Analysis of aperture averaging measurements. [laser scintillation data on the effect of atmospheric turbulence on signal fluctuations

NASA Technical Reports Server (NTRS)

Fried, D. L.

1975-01-01

Laser scintillation data obtained by the NASA Goddard Space Flight Center balloon flight no. 5 from White Sands Missile Range on 19 October 1973 are analyzed. The measurement data, taken with various size receiver apertures, were related to predictions of aperture averaging theory, and it is concluded that the data are in reasonable agreement with theory. The following parameters are assigned to the vertical distribution of the strength of turbulence during the period of the measurements (daytime), for lambda = 0.633 microns, and the source at the zenith; the aperture averaging length is d sub o = 0.125 m, and the log-amplitude variance is (beta sub l)2 = 0.084 square nepers. This corresponds to a normalized point intensity variance of 0.40.

An Evaluation of Psychophysical Models of Auditory Change Perception

PubMed Central

Micheyl, Christophe; Kaernbach, Christian; Demany, Laurent

2009-01-01

In many psychophysical experiments, the participant's task is to detect small changes along a given stimulus dimension, or to identify the direction (e.g., upward vs. downward) of such changes. The results of these experiments are traditionally analyzed using a constant-variance Gaussian (CVG) model or a high-threshold (HT) model. Here, the authors demonstrate that for changes along three basic sound dimensions (frequency, intensity, and amplitude-modulation rate), such models cannot account for the observed relationship between detection thresholds and direction-identification thresholds. It is shown that two alternative models can account for this relationship. One of them is based on the idea of sensory “quanta”; the other assumes that small changes are detected on the basis of Poisson processes with low means. The predictions of these two models are then compared against receiver operating characteristics (ROCs) for the detection of changes in sound intensity. It is concluded that human listeners' perception of small and unidimensional acoustic changes is better described by a discrete-state Poisson model than by the more commonly used CVG model or by the less favored HT and quantum models. PMID:18954215

Probability theory for 3-layer remote sensing radiative transfer model: univariate case.

PubMed

Ben-David, Avishai; Davidson, Charles E

2012-04-23

A probability model for a 3-layer radiative transfer model (foreground layer, cloud layer, background layer, and an external source at the end of line of sight) has been developed. The 3-layer model is fundamentally important as the primary physical model in passive infrared remote sensing. The probability model is described by the Johnson family of distributions that are used as a fit for theoretically computed moments of the radiative transfer model. From the Johnson family we use the SU distribution that can address a wide range of skewness and kurtosis values (in addition to addressing the first two moments, mean and variance). In the limit, SU can also describe lognormal and normal distributions. With the probability model one can evaluate the potential for detecting a target (vapor cloud layer), the probability of observing thermal contrast, and evaluate performance (receiver operating characteristics curves) in clutter-noise limited scenarios. This is (to our knowledge) the first probability model for the 3-layer remote sensing geometry that treats all parameters as random variables and includes higher-order statistics. © 2012 Optical Society of America

Extraction of Capillary Non-perfusion from Fundus Fluorescein Angiogram

NASA Astrophysics Data System (ADS)

Sivaswamy, Jayanthi; Agarwal, Amit; Chawla, Mayank; Rani, Alka; Das, Taraprasad

Capillary Non-Perfusion (CNP) is a condition in diabetic retinopathy where blood ceases to flow to certain parts of the retina, potentially leading to blindness. This paper presents a solution for automatically detecting and segmenting CNP regions from fundus fluorescein angiograms (FFAs). CNPs are modelled as valleys, and a novel technique based on extrema pyramid is presented for trough-based valley detection. The obtained valley points are used to segment the desired CNP regions by employing a variance-based region growing scheme. The proposed algorithm has been tested on 40 images and validated against expert-marked ground truth. In this paper, we present results of testing and validation of our algorithm against ground truth and compare the segmentation performance against two others methods.The performance of the proposed algorithm is presented as a receiver operating characteristic (ROC) curve. The area under this curve is 0.842 and the distance of ROC from the ideal point (0,1) is 0.31. The proposed method for CNP segmentation was found to outperform the watershed [1] and heat-flow [2] based methods.

Recent developments in the Dorfman-Berbaum-Metz procedure for multireader ROC study analysis.

PubMed

Hillis, Stephen L; Berbaum, Kevin S; Metz, Charles E

2008-05-01

The Dorfman-Berbaum-Metz (DBM) method has been one of the most popular methods for analyzing multireader receiver-operating characteristic (ROC) studies since it was proposed in 1992. Despite its popularity, the original procedure has several drawbacks: it is limited to jackknife accuracy estimates, it is substantially conservative, and it is not based on a satisfactory conceptual or theoretical model. Recently, solutions to these problems have been presented in three papers. Our purpose is to summarize and provide an overview of these recent developments. We present and discuss the recently proposed solutions for the various drawbacks of the original DBM method. We compare the solutions in a simulation study and find that they result in improved performance for the DBM procedure. We also compare the solutions using two real data studies and find that the modified DBM procedure that incorporates these solutions yields more significant results and clearer interpretations of the variance component parameters than the original DBM procedure. We recommend using the modified DBM procedure that incorporates the recent developments.

No special K! A signal detection framework for the strategic regulation of memory accuracy.

PubMed

Higham, Philip A

2007-02-01

Two experiments investigated criterion setting and metacognitive processes underlying the strategic regulation of accuracy on the Scholastic Aptitude Test (SAT) using Type-2 signal detection theory (SDT). In Experiment 1, report bias was manipulated by penalizing participants either 0.25 (low incentive) or 4 (high incentive) points for each error. Best guesses to unanswered items were obtained so that Type-2 signal detection indices of discrimination and bias could be calculated. The same incentive manipulation was used in Experiment 2, only the test was computerized, confidence ratings were taken so that receiver operating characteristic (ROC) curves could be generated, and feedback was manipulated. The results of both experiments demonstrated that SDT provides a viable alternative to A. Koriat and M. Goldsmith's (1996c) framework of monitoring and control and reveals information about the regulation of accuracy that their framework does not. For example, ROC analysis indicated that the threshold model implied by formula scoring is inadequate. Instead, performance on the SAT should be modeled with an equal-variance Gaussian, Type-2 signal detection model. ((c) 2007 APA, all rights reserved).

Utilization of all Spectral Channels of IASI for the Retrieval of the Atmospheric State

NASA Astrophysics Data System (ADS)

Del Bianco, S.; Cortesi, U.; Carli, B.

2010-12-01

The retrieval of atmospheric state parameters from broadband measurements acquired by high spectral resolution sensors, such as the Infrared Atmospheric Sounding Interferometer (IASI) onboard the Meteorological Operational (MetOp) platform, generally requires to deal with a prohibitively large number of spectral elements available from a single observation (8461 samples in the case of IASI, covering the 645-2760 cm-1 range with a resolution of 0.5 cm-1 and a spectral sampling of 0.25 cm-1). Most inversion algorithms developed for both operational and scientific analysis of IASI spectra perform a reduction of the data - typically based on channel selection, super-channel clustering or Principal Component Analysis (PCA) techniques - in order to handle the high dimensionality of the problem. Accordingly, simultaneous processing of all IASI channels received relatively low attention. Here we prove the feasibility of a retrieval approach exploiting all spectral channels of IASI, to extract information on water vapor, temperature and ozone profiles. This multi-target retrieval removes the systematic errors due to interfering parameters and makes the channel selection no longer necessary. The challenging computation is made possible by the use of a coarse spectral grid for the forward model calculation and by the abatement of the associated modeling errors through the use of a variance-covariance matrix of the residuals that takes into account all the forward model errors.

Optimization of electrocoagulation process to treat grey wastewater in batch mode using response surface methodology

PubMed Central

2014-01-01

Background Discharge of grey wastewater into the ecological system causes the negative impact effect on receiving water bodies. Methods In this present study, electrocoagulation process (EC) was investigated to treat grey wastewater under different operating conditions such as initial pH (4–8), current density (10–30 mA/cm2), electrode distance (4–6 cm) and electrolysis time (5–25 min) by using stainless steel (SS) anode in batch mode. Four factors with five levels Box-Behnken response surface design (BBD) was employed to optimize and investigate the effect of process variables on the responses such as total solids (TS), chemical oxygen demand (COD) and fecal coliform (FC) removal. Results The process variables showed significant effect on the electrocoagulation treatment process. The results were analyzed by Pareto analysis of variance (ANOVA) and second order polynomial models were developed in order to study the electrocoagulation process statistically. The optimal operating conditions were found to be: initial pH of 7, current density of 20 mA/cm2, electrode distance of 5 cm and electrolysis time of 20 min. Conclusion These results indicated that EC process can be scale up in large scale level to treat grey wastewater with high removal efficiency of TS, COD and FC. PMID:24410752

Phase error statistics of a phase-locked loop synchronized direct detection optical PPM communication system

NASA Technical Reports Server (NTRS)

Natarajan, Suresh; Gardner, C. S.

1987-01-01

Receiver timing synchronization of an optical Pulse-Position Modulation (PPM) communication system can be achieved using a phased-locked loop (PLL), provided the photodetector output is suitably processed. The magnitude of the PLL phase error is a good indicator of the timing error at the receiver decoder. The statistics of the phase error are investigated while varying several key system parameters such as PPM order, signal and background strengths, and PPL bandwidth. A practical optical communication system utilizing a laser diode transmitter and an avalanche photodiode in the receiver is described, and the sampled phase error data are presented. A linear regression analysis is applied to the data to obtain estimates of the relational constants involving the phase error variance and incident signal power.

The Multidimensional Influence of Acculturation on Digit Symbol-Coding and Wisconsin Card Sorting Test in Hispanics.

PubMed

Krch, Denise; Lequerica, Anthony; Arango-Lasprilla, Juan Carlos; Rogers, Heather L; DeLuca, John; Chiaravalloti, Nancy D

2015-01-01

The purpose of the current study was to evaluate the relative contribution of acculturation to two tests of nonverbal test performance in Hispanics. This study compared 40 Hispanic and 20 non-Hispanic whites on Digit Symbol-Coding (DSC) and the Wisconsin Card Sorting Test (WCST) and evaluated the relative contribution of the various acculturation components to cognitive test performance in the Hispanic group. Hispanics performed significantly worse on DSC and WCST relative to non-Hispanic whites. Multiple regressions conducted within the Hispanic group revealed that language use uniquely accounted for 11.0% of the variance on the DSC, 18.8% of the variance on WCST categories completed, and 13.0% of the variance in perseverative errors on the WCST. Additionally, years of education in the United States uniquely accounted for 14.9% of the variance in DSC. The significant impact of acculturation on DSC and WCST lends support that nonverbal cognitive tests are not necessarily culture free. The differential contribution of acculturation proxies highlights the importance of considering these separate components when interpreting performance on neuropsychological tests in clinical and research settings. Factors, such as the country where education was received, may in fact be more meaningful information than the years of education of education attained. Thus, acculturation should be considered an important factor in any cognitive evaluation of culturally diverse individuals.

Digital simulation of hybrid loop operation in RFI backgrounds.

NASA Technical Reports Server (NTRS)

Ziemer, R. E.; Nelson, D. R.

1972-01-01

A digital computer model for Monte-Carlo simulation of an imperfect second-order hybrid phase-locked loop (PLL) operating in radio-frequency interference (RFI) and Gaussian noise backgrounds has been developed. Characterization of hybrid loop performance in terms of cycle slipping statistics and phase error variance, through computer simulation, indicates that the hybrid loop has desirable performance characteristics in RFI backgrounds over the conventional PLL or the costas loop.

To Serve the Nation: U.S. Special Operations Forces in an Era of Persistent Conflict

DTIC Science & Technology

2010-06-01

presidential decisions, however, will not survive beyond any one particu- lar administration or even a specific operation. Additionally, many interagency...Security, and Energy, as well as with the Coast Guard, Federal Bureau of Investigation, Drug Enforcement Administration , and the Agency for...of relative variance in outcome. See, for example, Rose McDermott, Risk-Taking in International Politics: Prospect Theory in American Foreign Policy

Do radio frequencies of medical instruments common in the operating room interfere with near-infrared spectroscopy signals?

NASA Astrophysics Data System (ADS)

Shadgan, Babak; Molavi, Behnam; Reid, W. D.; Dumont, Guy; Macnab, Andrew J.

2010-02-01

Background: Medical and diagnostic applications of near infrared spectroscopy (NIRS) are increasing, especially in operating rooms (OR). Since NIRS is an optical technique, radio frequency (RF) interference from other instruments is unlikely to affect the raw optical data, however, NIRS data processing and signal output could be affected. Methods: We investigated the potential for three common OR instruments: an electrical cautery, an orthopaedic drill and an imaging system, to generate electromagnetic interference (EMI) that could potentially influence NIRS signals. The time of onset and duration of every operation of each device was recorded during surgery. To remove the effects of slow changing physiological variables, we first used a lowpass filter and then selected 2 windows with variable lengths around the moment of device onset. For each instant, variances (energy) and means of the signals in the 2 windows were compared. Results: Twenty patients were studied during ankle surgery. Analysis shows no statistically significant difference in the means and variance of the NIRS signals (p < 0.01) during operation of any of the three devices for all surgeries. Conclusion: This method confirms the instruments evaluated caused no significant interference. NIRS can potentially be used without EMI in clinical environments such as the OR.

Application of Non-Equilibrium Thermo Field Dynamics to quantum teleportation under the environment

NASA Astrophysics Data System (ADS)

Kitajima, S.; Arimitsu, T.; Obinata, M.; Yoshida, K.

2014-06-01

Quantum teleportation for continuous variables is treated by Non-Equilibrium Thermo Field Dynamics (NETFD), a canonical operator formalism for dissipative quantum systems, in order to study the effect of imperfect quantum entanglement on quantum communication. We used an entangled state constructed by two squeezed states. The entangled state is imperfect due to two reasons, i.e., one is the finiteness of the squeezing parameter r and the other comes from the process that the squeezed states are created under the dissipative interaction with the environment. We derive the expressions for one-shot fidelity (OSF), probability density function (PDF) associated with OSF and (averaged) fidelity by making full use of the algebraic manipulation of operator algebra within NETFD. We found that OSF and PDF are given by Gaussian forms with its peak at the original information α to be teleported, and that for r≫1 the variances of these quantities blow up to infinity for κ/χ≤1, while they approach to finite values for κ/χ>1. Here, χ represents the intensity of a degenerate parametric process, and κ the relaxation rate due to the interaction with the environment. The blow-up of the variances for OSF and PDF guarantees higher security against eavesdropping. With the blow-up of the variances, the height of PDF reduces to small because of the normalization of probability, while the height of OSF approaches to 1 indicating a higher performance of the quantum teleportation. We also found that in the limit κ/χ≫1 the variances of both OSF and PDF for any value of r (>0) reduce to 1 which is the same value as the case r=0, i.e., no entanglement.

Country of residence, gender equality and victim blaming attitudes about partner violence: a multilevel analysis in EU.

PubMed

Ivert, Anna-Karin; Merlo, Juan; Gracia, Enrique

2017-09-27

Intimate partner violence against women (IPVAW) is a global and preventable public health problem. Public attitudes, such as victim-blaming, are important for our understanding of differences in the occurrence of IPVAW, as they contribute to its justification. In this paper, we focus on victim-blaming attitudes regarding IPVAW within the EU and we apply multilevel analyses to identify contextual determinants of victim-blaming attitudes. We investigate both the general contextual effect of the country and the specific association between country level of gender equality and individual victim-blaming attitudes, as well as to what extend a possible general contextual effect was explained by county level gender equality. We analyzed data from 26 800 respondents from 27 member states of the European Union who responded to a survey on public perceptions of domestic violence. We applied multilevel logistic regression analysis and measures of variance (intra-class correlation (ICC)) were calculated, as well as the discriminatory accuracy by calculating the area under the receiver operator characteristic curve. Over and above individual characteristics, about 15% of the individual variance in the propensity for having victim-blaming attitudes was found at the country level, and country level of gender equality did not affect the general contextual effect (i.e. ICC) of the country on individual victim-blaming attitudes. The present study shows that there are important between-country differences in victim-blaming attitudes that cannot be explained by differences in individual-level demographics or in gender equality at the country level. More research on attitudes towards IPVAW is needed. © The Author 2017. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

Coefficient of Variance as Quality Criterion for Evaluation of Advanced Hepatic Fibrosis Using 2D Shear-Wave Elastography.

PubMed

Lim, Sanghyeok; Kim, Seung Hyun; Kim, Yongsoo; Cho, Young Seo; Kim, Tae Yeob; Jeong, Woo Kyoung; Sohn, Joo Hyun

2018-02-01

To compare the diagnostic performance for advanced hepatic fibrosis measured by 2D shear-wave elastography (SWE), using either the coefficient of variance (CV) or the interquartile range divided by the median value (IQR/M) as quality criteria. In this retrospective study, from January 2011 to December 2013, 96 patients, who underwent both liver stiffness measurement by 2D SWE and liver biopsy for hepatic fibrosis grading, were enrolled. The diagnostic performances of the CV and the IQR/M were analyzed using receiver operating characteristic curves with areas under the curves (AUCs) and were compared by Fisher's Z test, based on matching the cutoff points in an interactive dot diagram. All P values less than 0.05 were considered significant. When using the cutoff value IQR/M of 0.21, the matched cutoff point of CV was 20%. When a cutoff value of CV of 20% was used, the diagnostic performance for advanced hepatic fibrosis ( ≥ F3 grade) with CV of less than 20% was better than that in the group with CV greater than or equal to 20% (AUC 0.967 versus 0.786, z statistic = 2.23, P = .025), whereas when the matched cutoff value IQR/M of 0.21 showed no difference (AUC 0.918 versus 0.927, z statistic = -0.178, P = .859). The validity of liver stiffness measurements made by 2D SWE for assessing advanced hepatic fibrosis may be judged using CVs, and when the CV is less than 20% it can be considered "more reliable" than using IQR/M of less than 0.21. © 2017 by the American Institute of Ultrasound in Medicine.

75 FR 62874 - Keystone Steel and Wire Company; Grant of a Permanent Variance

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-13

... the crane-motor cleaning operation by inserting the nozzle of the compressed-air gun into an opening... inserting the nozzle of the compressed-air gun into an opening in the housing, then triggers the compressed...

Send-side matching of data communications messages

DOEpatents

Archer, Charles J.; Blocksome, Michael A.; Ratterman, Joseph D.; Smith, Brian E.

2014-07-01

Send-side matching of data communications messages includes a plurality of compute nodes organized for collective operations, including: issuing by a receiving node to source nodes a receive message that specifies receipt of a single message to be sent from any source node, the receive message including message matching information, a specification of a hardware-level mutual exclusion device, and an identification of a receive buffer; matching by two or more of the source nodes the receive message with pending send messages in the two or more source nodes; operating by one of the source nodes having a matching send message the mutual exclusion device, excluding messages from other source nodes with matching send messages and identifying to the receiving node the source node operating the mutual exclusion device; and sending to the receiving node from the source node operating the mutual exclusion device a matched pending message.

Geodetic positioning of the Aerospace Electronics Research Lab (ERL) Osborne Time Transfer Receiver (TTR) using the GPS NAVSTAR Block I satellites

NASA Technical Reports Server (NTRS)

Liu, Anthony S.

1990-01-01

Aerospace has routinely processed the Osborne Time Transfer Receiver (TTR) data for the purpose of monitoring the performance of ground and GPS atomic clocks in near real-time with on-line residual displays and characterizing clock stability with Allan Variance calculations. Recently, Aerospace added the ability to estimate the TTR's location by differentially correcting the TTR's location in the WGS84 reference system. This new feature is exercised on a set of TTR clock phase data and Sub-meter accurate station location estimates of the TTR at the Aerospace Electronic Research Lab (ERL) are obtained.

Explaining Variance in Long-Term Recall in 3- and 4-Year-Old Children: The Importance of Post-Encoding Processes

ERIC Educational Resources Information Center

Bauer, Patricia J.; Larkina, Marina; Doydum, Ayzit O.

2012-01-01

Long-term recall is influenced by what originally was encoded as well as by the efficacy of retrieval processes. The possible explanatory role of post-encoding processes by which initially labile memory traces are stabilized and integrated into long-term memory (i.e., consolidated) has received relatively less research attention. In the current…

[Impact of attachment style, social support and the number of implantable cardioverter defibrillator (ICD) discharges on psychological strain of ICD patients].

PubMed

Simson, Udo; Perings, Christian; Plaskuda, Ariane; Schäfer, Ralf; Brehm, Michael; Bader, Doris; Tress, Wolfgang; Franz, Matthias

2006-12-01

OBJECTIVE It is well known fact, that the life of ICD patients is often affected by anxiety and depression. The number of ICD discharges is only a contributing factor explaining the variance of anxiety and depression. There have to be other factors that have more influence on the physical strain of ICD patients. In this study we examined the impact of attachment style and social support in addition to the number of ICD discharges. METHODS 119 out-patients at an out-patient ICD unit were examined consecutively with the following self report scales: (1) the State-Trait-Anxiety Inventory (STAI), (2) the Beck Depression Inventory (BDI), (3) a short form of a social support questionnaire (F-SOZU), (4) the Bielefeld Partnership Expectations Questionnaire (BFPE) and (5) a specifically designed questionnaire for the assessment of sociodemografic data. To determine the frequency and timing of the ICD discharges we analysed the ICD data. RESULTS 38 % of the ICD patients reported enhanced anxiety levels and 37 % reported enhanced depression levels. Only 38 % of the ICD patients received discharges at all. Elevated levels of anxiety and depression were found in patients who showed insecure attachment styles, low social support, long-term treatment in hospital and a higher number of ICD discharges. To explain the variance of anxiety we found social support, attachment style, and the number of ICD storms to be contributing factors. To explain the variance of depression we found social support and time spent in hospital in the previous year to be contributing factors. CONCLUSIONS Almost half of the ICD patients suffer considerably from anxiety and/or depression. These patients have to be identified and treated psychotherapeutically. Patients who show insecure attachment styles, receive low social support, undergo long-term treatment in hospital and receive a higher number of discharges, especially so called ICD storms, bear the highest risk to develop psychological strain. Attachment style and social support have even more impact on the development of anxiety and depression than the number of ICD discharges. It has to be shown in future studies whether psychotherapy can improve the quality of life of ICD patients.

29 CFR 1917.155 - Air receivers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 7 2012-07-01 2012-07-01 false Air receivers. 1917.155 Section 1917.155 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.155 Air receivers. (a) Application. This section applies to compressed air receivers and equipment used for operations such as cleaning...

29 CFR 1917.155 - Air receivers.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 7 2014-07-01 2014-07-01 false Air receivers. 1917.155 Section 1917.155 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.155 Air receivers. (a) Application. This section applies to compressed air receivers and equipment used for operations such as cleaning...

29 CFR 1917.155 - Air receivers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 7 2013-07-01 2013-07-01 false Air receivers. 1917.155 Section 1917.155 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.155 Air receivers. (a) Application. This section applies to compressed air receivers and equipment used for operations such as cleaning...

29 CFR 1917.155 - Air receivers.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 7 2011-07-01 2011-07-01 false Air receivers. 1917.155 Section 1917.155 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.155 Air receivers. (a) Application. This section applies to compressed air receivers and equipment used for operations such as cleaning...

29 CFR 1917.155 - Air receivers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Air receivers. 1917.155 Section 1917.155 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.155 Air receivers. (a) Application. This section applies to compressed air receivers and equipment used for operations such as cleaning...

Complete Versus Incomplete Angiography Prior to Percutaneous Coronary Intervention in ST-Elevation Myocardial Infarction.

PubMed

Stiver, Kevin; Gao, Xu; Shreenivas, Satya; Boudoulas, Konstantinos Dean; Mazzaferri, Ernie; Makki, Nader; Lilly, Scott M

2017-08-01

Shorter reperfusion times in ST-elevation myocardial infarction (STEMI) are associated with improved survival. Prehospital strategies have been developed to minimize door-to-balloon (DTB) time, but few strategies within the catheterization laboratory itself have been evaluated. Incomplete angiography (IA) prior to percutaneous coronary intervention (PCI) is undertaken in clinical practice as a means to further reduce DTB time. We sought to determine whether or not those with STEMI who underwent IA prior to PCI had different preprocedural characteristics or post-PCI outcomes. We retrospectively reviewed patients presenting to our institution between March 2013 and December 2015. Clinical, demographic, and angiographic data were reviewed. The frequency, predictors, and outcomes among those who received IA vs complete angiography (CA) prior to PCI were compared with analysis of variance. Two hundred fifty-six patients were identified; 68 patients (26.6%) underwent IA and 188 patients (73.4%) had CA prior to PCI. Patients who received IA were younger, but no other preprocedural factors were predictive of IA. The practice of IA did vary by operator (range, 0%-47%; P<.01). DTB times were shorter in the IA group (28.1 min vs 37.3 min; P<.01). Overall outcomes, including peak troponin values, length of stay, in-hospital mortality, and discharge ejection fraction did not differ between the groups. IA is associated with shorter DTB times, although in this population was not associated with improvements in short-term outcomes.

Gene expression-based dosimetry by dose and time in mice following acute radiation exposure.

PubMed

Tucker, James D; Divine, George W; Grever, William E; Thomas, Robert A; Joiner, Michael C; Smolinski, Joseph M; Auner, Gregory W

2013-01-01

Rapid and reliable methods for performing biological dosimetry are of paramount importance in the event of a large-scale nuclear event. Traditional dosimetry approaches lack the requisite rapid assessment capability, ease of use, portability and low cost, which are factors needed for triaging a large number of victims. Here we describe the results of experiments in which mice were acutely exposed to (60)Co gamma rays at doses of 0 (control) to 10 Gy. Blood was obtained from irradiated mice 0.5, 1, 2, 3, 5, and 7 days after exposure. mRNA expression levels of 106 selected genes were obtained by reverse-transcription real time PCR. Stepwise regression of dose received against individual gene transcript expression levels provided optimal dosimetry at each time point. The results indicate that only 4-7 different gene transcripts are needed to explain ≥ 0.69 of the variance (R(2)), and that receiver-operator characteristics, a measure of sensitivity and specificity, of ≥ 0.93 for these statistical models were achieved at each time point. These models provide an excellent description of the relationship between the actual and predicted doses up to 6 Gy. At doses of 8 and 10 Gy there appears to be saturation of the radiation-response signals with a corresponding diminution of accuracy. These results suggest that similar analyses in humans may be advantageous for use in a field-portable device designed to assess exposures in mass casualty situations.

Geometrical Monte Carlo simulation of atmospheric turbulence

NASA Astrophysics Data System (ADS)

Yuksel, Demet; Yuksel, Heba

2013-09-01

Atmospheric turbulence has a significant impact on the quality of a laser beam propagating through the atmosphere over long distances. Turbulence causes intensity scintillation and beam wander from propagation through turbulent eddies of varying sizes and refractive index. This can severely impair the operation of target designation and Free-Space Optical (FSO) communications systems. In addition, experimenting on an FSO communication system is rather tedious and difficult. The interferences of plentiful elements affect the result and cause the experimental outcomes to have bigger error variance margins than they are supposed to have. Especially when we go into the stronger turbulence regimes the simulation and analysis of the turbulence induced beams require delicate attention. We propose a new geometrical model to assess the phase shift of a laser beam propagating through turbulence. The atmosphere along the laser beam propagation path will be modeled as a spatial distribution of spherical bubbles with refractive index discontinuity calculated from a Gaussian distribution with the mean value being the index of air. For each statistical representation of the atmosphere, the path of rays will be analyzed using geometrical optics. These Monte Carlo techniques will assess the phase shift as a summation of the phases that arrive at the same point at the receiver. Accordingly, there would be dark and bright spots at the receiver that give an idea regarding the intensity pattern without having to solve the wave equation. The Monte Carlo analysis will be compared with the predictions of wave theory.

Laparoscopic-guided abdominal wall nerve blocks in the pediatric population: a novel technique with comparison to ultrasound-guided blocks and local wound infiltration alone.

PubMed

Landmann, Alessandra; Visoiu, Mihaela; Malek, Marcus M

2018-03-01

Abdominal wall nerve blocks have been gaining popularity for the treatment of perioperative pain in children. Our aim was to compare a technique of surgeon-performed, laparoscopic abdominal wall nerve blocks to anesthesia-placed, ultrasound-guided abdominal wall nerve blocks and the current standard of local wound infiltration. After institutional review board approval was obtained, a retrospective chart review was performed of pediatric patients treated at a single institution during a 2-year period. Statistics were calculated using analysis of variance with post-hoc Bonferonni t tests for pair-wise comparisons. Included in this study were 380 patients who received ultrasound-guided abdominal wall nerve blocks (n = 125), laparoscopic-guided abdominal wall nerve blocks (n = 88), and local wound infiltration (n = 117). Groups were well matched for age, sex, and weight. There was no significant difference in pain scores within the first 8 hours or narcotic usage between groups. Local wound infiltration demonstrated the shortest overall time required to perform (P < .0001). Patients who received a surgeon-performed abdominal wall nerve block demonstrated a shorter duration of hospital stay when compared to the other groups (P = .02). Our study has demonstrated that laparoscopic-guided abdominal wall nerve blocks show similar efficacy to ultrasound-guided nerve blocks performed by pain management physicians without increasing time in the operating room. Copyright © 2017 Elsevier Inc. All rights reserved.

Predictions of GPS X-Set Performance during the Places Experiment

DTIC Science & Technology

1979-07-01

previously existing GPS X-set receiver simulation was modified to include the received signal spectrum and the receiver code correlation operation... CORRELATION OPERATION The X-set receiver simulation documented in Reference 3-1 is a direct sampled -data digital implementation of the GPS X-set...ul(t) -sin w2t From Carrier and Code Loops (wit +0 1 (t)) Figure 3-6. Simplified block diagram of code correlator operation and I-Q sampling . 6 I

Comparison of amplitude-decorrelation, speckle-variance and phase-variance OCT angiography methods for imaging the human retina and choroid

PubMed Central

Gorczynska, Iwona; Migacz, Justin V.; Zawadzki, Robert J.; Capps, Arlie G.; Werner, John S.

2016-01-01

We compared the performance of three OCT angiography (OCTA) methods: speckle variance, amplitude decorrelation and phase variance for imaging of the human retina and choroid. Two averaging methods, split spectrum and volume averaging, were compared to assess the quality of the OCTA vascular images. All data were acquired using a swept-source OCT system at 1040 nm central wavelength, operating at 100,000 A-scans/s. We performed a quantitative comparison using a contrast-to-noise (CNR) metric to assess the capability of the three methods to visualize the choriocapillaris layer. For evaluation of the static tissue noise suppression in OCTA images we proposed to calculate CNR between the photoreceptor/RPE complex and the choriocapillaris layer. Finally, we demonstrated that implementation of intensity-based OCT imaging and OCT angiography methods allows for visualization of retinal and choroidal vascular layers known from anatomic studies in retinal preparations. OCT projection imaging of data flattened to selected retinal layers was implemented to visualize retinal and choroidal vasculature. User guided vessel tracing was applied to segment the retinal vasculature. The results were visualized in a form of a skeletonized 3D model. PMID:27231598

Experimental investigation of the intensity fluctuation joint probability and conditional distributions of the twin-beam quantum state.

PubMed

Zhang, Yun; Kasai, Katsuyuki; Watanabe, Masayoshi

2003-01-13

We give the intensity fluctuation joint probability of the twin-beam quantum state, which was generated with an optical parametric oscillator operating above threshold. Then we present what to our knowledge is the first measurement of the intensity fluctuation conditional probability distributions of twin beams. The measured inference variance of twin beams 0.62+/-0.02, which is less than the standard quantum limit of unity, indicates inference with a precision better than that of separable states. The measured photocurrent variance exhibits a quantum correlation of as much as -4.9+/-0.2 dB between the signal and the idler.

Estimation of stable boundary-layer height using variance processing of backscatter lidar data

NASA Astrophysics Data System (ADS)

Saeed, Umar; Rocadenbosch, Francesc

2017-04-01

Stable boundary layer (SBL) is one of the most complex and less understood topics in atmospheric science. The type and height of the SBL is an important parameter for several applications such as understanding the formation of haze fog, and accuracy of chemical and pollutant dispersion models, etc. [1]. This work addresses nocturnal Stable Boundary-Layer Height (SBLH) estimation by using variance processing and attenuated backscatter lidar measurements, its principles and limitations. It is shown that temporal and spatial variance profiles of the attenuated backscatter signal are related to the stratification of aerosols in the SBL. A minimum variance SBLH estimator using local minima in the variance profiles of backscatter lidar signals is introduced. The method is validated using data from HD(CP)2 Observational Prototype Experiment (HOPE) campaign at Jülich, Germany [2], under different atmospheric conditions. This work has received funding from the European Union Seventh Framework Programme, FP7 People, ITN Marie Curie Actions Programme (2012-2016) in the frame of ITaRS project (GA 289923), H2020 programme under ACTRIS-2 project (GA 654109), the Spanish Ministry of Economy and Competitiveness - European Regional Development Funds under TEC2015-63832-P project, and from the Generalitat de Catalunya (Grup de Recerca Consolidat) 2014-SGR-583. [1] R. B. Stull, An Introduction to Boundary Layer Meteorology, chapter 12, Stable Boundary Layer, pp. 499-543, Springer, Netherlands, 1988. [2] U. Löhnert, J. H. Schween, C. Acquistapace, K. Ebell, M. Maahn, M. Barrera-Verdejo, A. Hirsikko, B. Bohn, A. Knaps, E. O'Connor, C. Simmer, A. Wahner, and S. Crewell, "JOYCE: Jülich Observatory for Cloud Evolution," Bull. Amer. Meteor. Soc., vol. 96, no. 7, pp. 1157-1174, 2015.

Performance prediction evaluation of ceramic materials in point-focusing solar receivers

NASA Technical Reports Server (NTRS)

Ewing, J.; Zwissler, J.

1979-01-01

A performance prediction was adapted to evaluate the use of ceramic materials in solar receivers for point focusing distributed applications. System requirements were determined including the receiver operating environment and system operating parameters for various engine types. Preliminary receiver designs were evolved from these system requirements. Specific receiver designs were then evaluated to determine material functional requirements.

On the internal target model in a tracking task

NASA Technical Reports Server (NTRS)

Caglayan, A. K.; Baron, S.

1981-01-01

An optimal control model for predicting operator's dynamic responses and errors in target tracking ability is summarized. The model, which predicts asymmetry in the tracking data, is dependent on target maneuvers and trajectories. Gunners perception, decision making, control, and estimate of target positions and velocity related to crossover intervals are discussed. The model provides estimates for means, standard deviations, and variances for variables investigated and for operator estimates of future target positions and velocities.

Quantifying the uncertainty in heritability.

PubMed

Furlotte, Nicholas A; Heckerman, David; Lippert, Christoph

2014-05-01

The use of mixed models to determine narrow-sense heritability and related quantities such as SNP heritability has received much recent attention. Less attention has been paid to the inherent variability in these estimates. One approach for quantifying variability in estimates of heritability is a frequentist approach, in which heritability is estimated using maximum likelihood and its variance is quantified through an asymptotic normal approximation. An alternative approach is to quantify the uncertainty in heritability through its Bayesian posterior distribution. In this paper, we develop the latter approach, make it computationally efficient and compare it to the frequentist approach. We show theoretically that, for a sufficiently large sample size and intermediate values of heritability, the two approaches provide similar results. Using the Atherosclerosis Risk in Communities cohort, we show empirically that the two approaches can give different results and that the variance/uncertainty can remain large.

Evaluation of A Novel Information-Sharing Instrument for Home-Based Palliative Care

PubMed Central

Sawada, Koichiro; Shimada, Masanari; Kadoya, Shinichi; Endo, Naoki; Ishiguro, Kaname; Takashima, Rumi; Amemiya, Yoko; Fujikawa, Yasunaga; Ikezaki, Tomoaki; Takeuchi, Miyako; Kitazawa, Hidenori; Iida, Hiroyuki; Koseki, Shiro; Morita, Tatsuya; Sasaki, Koji; Kashii, Tatsuhiko; Murakami, Nozomu

2015-01-01

Aim: To examine the feasibility and usefulness of a novel region-based pathway: the Regional Referral Clinical Pathway for Home-Based Palliative Care. Method: This was a feasibility study to evaluate the frequency of variances and the perceived usefulness of pathway using in-depth interviews. All patients with cancer referred to the palliative care team between 2011 and 2013 and received home care services were enrolled. Result: A total of 44 patients were analyzed, and pathway was completed in all the patients. The target outcome was achieved in 61.4% while some variances occurred in 54.5%. Nine categories were identified as the usefulness of the pathway, such as reviewing and sharing information and promoting communication, education, motivation, and relationships. Conclusion: This novel pathway is feasible and seems to be useful. PMID:24814723

Nonalcoholic Fatty Liver Disease: MR Imaging of Liver Proton Density Fat Fraction to Assess Hepatic Steatosis

PubMed Central

Tang, An; Tan, Justin; Sun, Mark; Hamilton, Gavin; Bydder, Mark; Wolfson, Tanya; Gamst, Anthony C.; Middleton, Michael; Brunt, Elizabeth M.; Loomba, Rohit; Lavine, Joel E.; Schwimmer, Jeffrey B.

2013-01-01

Purpose: To evaluate the diagnostic performance of magnetic resonance (MR) imaging–estimated proton density fat fraction (PDFF) for assessing hepatic steatosis in nonalcoholic fatty liver disease (NAFLD) by using centrally scored histopathologic validation as the reference standard. Materials and Methods: This prospectively designed, cross-sectional, internal review board–approved, HIPAA-compliant study was conducted in 77 patients who had NAFLD and liver biopsy. MR imaging–PDFF was estimated from magnitude-based low flip angle multiecho gradient-recalled echo images after T2* correction and multifrequency fat modeling. Histopathologic scoring was obtained by consensus of the Nonalcoholic Steatohepatitis (NASH) Clinical Research Network Pathology Committee. Spearman correlation, additivity and variance stabilization for regression for exploring the effect of a number of potential confounders, and receiver operating characteristic analyses were performed. Results: Liver MR imaging–PDFF was systematically higher, with higher histologic steatosis grade (P < .001), and was significantly correlated with histologic steatosis grade (ρ = 0.69, P < .001). The correlation was not confounded by age, sex, lobular inflammation, hepatocellular ballooning, NASH diagnosis, fibrosis, or magnetic field strength (P = .65). Area under the receiver operating characteristic curves was 0.989 (95% confidence interval: 0.968, 1.000) for distinguishing patients with steatosis grade 0 (n = 5) from those with grade 1 or higher (n = 72), 0.825 (95% confidence interval: 0.734, 0.915) to distinguish those with grade 1 or lower (n = 31) from those with grade 2 or higher (n = 46), and 0.893 (95% confidence interval: 0.809, 0.977) to distinguish those with grade 2 or lower (n = 58) from those with grade 3 (n = 19). Conclusion: MR imaging–PDFF showed promise for assessment of hepatic steatosis grade in patients with NAFLD. For validation, further studies with larger sample sizes are needed. © RSNA, 2013 PMID:23382291

The SENSE-Isomorphism Theoretical Image Voxel Estimation (SENSE-ITIVE) Model for Reconstruction and Observing Statistical Properties of Reconstruction Operators

PubMed Central

Bruce, Iain P.; Karaman, M. Muge; Rowe, Daniel B.

2012-01-01

The acquisition of sub-sampled data from an array of receiver coils has become a common means of reducing data acquisition time in MRI. Of the various techniques used in parallel MRI, SENSitivity Encoding (SENSE) is one of the most common, making use of a complex-valued weighted least squares estimation to unfold the aliased images. It was recently shown in Bruce et al. [Magn. Reson. Imag. 29(2011):1267–1287] that when the SENSE model is represented in terms of a real-valued isomorphism, it assumes a skew-symmetric covariance between receiver coils, as well as an identity covariance structure between voxels. In this manuscript, we show that not only is the skew-symmetric coil covariance unlike that of real data, but the estimated covariance structure between voxels over a time series of experimental data is not an identity matrix. As such, a new model, entitled SENSE-ITIVE, is described with both revised coil and voxel covariance structures. Both the SENSE and SENSE-ITIVE models are represented in terms of real-valued isomorphisms, allowing for a statistical analysis of reconstructed voxel means, variances, and correlations resulting from the use of different coil and voxel covariance structures used in the reconstruction processes to be conducted. It is shown through both theoretical and experimental illustrations that the miss-specification of the coil and voxel covariance structures in the SENSE model results in a lower standard deviation in each voxel of the reconstructed images, and thus an artificial increase in SNR, compared to the standard deviation and SNR of the SENSE-ITIVE model where both the coil and voxel covariances are appropriately accounted for. It is also shown that there are differences in the correlations induced by the reconstruction operations of both models, and consequently there are differences in the correlations estimated throughout the course of reconstructed time series. These differences in correlations could result in meaningful differences in interpretation of results. PMID:22617147

Multiparametric Quantitative Ultrasound Imaging in Assessment of Chronic Kidney Disease.

PubMed

Gao, Jing; Perlman, Alan; Kalache, Safa; Berman, Nathaniel; Seshan, Surya; Salvatore, Steven; Smith, Lindsey; Wehrli, Natasha; Waldron, Levi; Kodali, Hanish; Chevalier, James

2017-11-01

To evaluate the value of multiparametric quantitative ultrasound imaging in assessing chronic kidney disease (CKD) using kidney biopsy pathologic findings as reference standards. We prospectively measured multiparametric quantitative ultrasound markers with grayscale, spectral Doppler, and acoustic radiation force impulse imaging in 25 patients with CKD before kidney biopsy and 10 healthy volunteers. Based on all pathologic (glomerulosclerosis, interstitial fibrosis/tubular atrophy, arteriosclerosis, and edema) scores, the patients with CKD were classified into mild (no grade 3 and <2 of grade 2) and moderate to severe (at least 2 of grade 2 or 1 of grade 3) CKD groups. Multiparametric quantitative ultrasound parameters included kidney length, cortical thickness, pixel intensity, parenchymal shear wave velocity, intrarenal artery peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index. We tested the difference in quantitative ultrasound parameters among mild CKD, moderate to severe CKD, and healthy controls using analysis of variance, analyzed correlations of quantitative ultrasound parameters with pathologic scores and the estimated glomerular filtration rate (GFR) using Pearson correlation coefficients, and examined the diagnostic performance of quantitative ultrasound parameters in determining moderate CKD and an estimated GFR of less than 60 mL/min/1.73 m 2 using receiver operating characteristic curve analysis. There were significant differences in cortical thickness, pixel intensity, PSV, and EDV among the 3 groups (all P < .01). Among quantitative ultrasound parameters, the top areas under the receiver operating characteristic curves for PSV and EDV were 0.88 and 0.97, respectively, for determining pathologic moderate to severe CKD, and 0.76 and 0.86 for estimated GFR of less than 60 mL/min/1.73 m 2 . Moderate to good correlations were found for PSV, EDV, and pixel intensity with pathologic scores and estimated GFR. The PSV, EDV, and pixel intensity are valuable in determining moderate to severe CKD. The value of shear wave velocity in assessing CKD needs further investigation. © 2017 by the American Institute of Ultrasound in Medicine.

Reliability and validity of the new Tanaka B Intelligence Scale scores: a group intelligence test.

PubMed

Uno, Yota; Mizukami, Hitomi; Ando, Masahiko; Yukihiro, Ryoji; Iwasaki, Yoko; Ozaki, Norio

2014-01-01

The present study evaluated the reliability and concurrent validity of the new Tanaka B Intelligence Scale, which is an intelligence test that can be administered on groups within a short period of time. The new Tanaka B Intelligence Scale and Wechsler Intelligence Scale for Children-Third Edition were administered to 81 subjects (mean age ± SD 15.2 ± 0.7 years) residing in a juvenile detention home; reliability was assessed using Cronbach's alpha coefficient, and concurrent validity was assessed using the one-way analysis of variance intraclass correlation coefficient. Moreover, receiver operating characteristic analysis for screening for individuals who have a deficit in intellectual function (an FIQ<70) was performed. In addition, stratum-specific likelihood ratios for detection of intellectual disability were calculated. The Cronbach's alpha for the new Tanaka B Intelligence Scale IQ (BIQ) was 0.86, and the intraclass correlation coefficient with FIQ was 0.83. Receiver operating characteristic analysis demonstrated an area under the curve of 0.89 (95% CI: 0.85-0.96). In addition, the stratum-specific likelihood ratio for the BIQ≤65 stratum was 13.8 (95% CI: 3.9-48.9), and the stratum-specific likelihood ratio for the BIQ≥76 stratum was 0.1 (95% CI: 0.03-0.4). Thus, intellectual disability could be ruled out or determined. The present results demonstrated that the new Tanaka B Intelligence Scale score had high reliability and concurrent validity with the Wechsler Intelligence Scale for Children-Third Edition score. Moreover, the post-test probability for the BIQ could be calculated when screening for individuals who have a deficit in intellectual function. The new Tanaka B Intelligence Test is convenient and can be administered within a variety of settings. This enables evaluation of intellectual development even in settings where performing intelligence tests have previously been difficult.

Reliability and Validity of the New Tanaka B Intelligence Scale Scores: A Group Intelligence Test

PubMed Central

Uno, Yota; Mizukami, Hitomi; Ando, Masahiko; Yukihiro, Ryoji; Iwasaki, Yoko; Ozaki, Norio

2014-01-01

Objective The present study evaluated the reliability and concurrent validity of the new Tanaka B Intelligence Scale, which is an intelligence test that can be administered on groups within a short period of time. Methods The new Tanaka B Intelligence Scale and Wechsler Intelligence Scale for Children-Third Edition were administered to 81 subjects (mean age ± SD 15.2±0.7 years) residing in a juvenile detention home; reliability was assessed using Cronbach’s alpha coefficient, and concurrent validity was assessed using the one-way analysis of variance intraclass correlation coefficient. Moreover, receiver operating characteristic analysis for screening for individuals who have a deficit in intellectual function (an FIQ<70) was performed. In addition, stratum-specific likelihood ratios for detection of intellectual disability were calculated. Results The Cronbach’s alpha for the new Tanaka B Intelligence Scale IQ (BIQ) was 0.86, and the intraclass correlation coefficient with FIQ was 0.83. Receiver operating characteristic analysis demonstrated an area under the curve of 0.89 (95% CI: 0.85–0.96). In addition, the stratum-specific likelihood ratio for the BIQ≤65 stratum was 13.8 (95% CI: 3.9–48.9), and the stratum-specific likelihood ratio for the BIQ≥76 stratum was 0.1 (95% CI: 0.03–0.4). Thus, intellectual disability could be ruled out or determined. Conclusion The present results demonstrated that the new Tanaka B Intelligence Scale score had high reliability and concurrent validity with the Wechsler Intelligence Scale for Children-Third Edition score. Moreover, the post-test probability for the BIQ could be calculated when screening for individuals who have a deficit in intellectual function. The new Tanaka B Intelligence Test is convenient and can be administered within a variety of settings. This enables evaluation of intellectual development even in settings where performing intelligence tests have previously been difficult. PMID:24940880

Macros for Educational Research.

ERIC Educational Resources Information Center

Woodrow, Janice E. J.

1988-01-01

Describes the design and operation of two macros written in the programming language of Microsoft's EXCEL for educational research applications. The first macro determines the frequency of responses to a Likert-type questionnaire or multiple-choice test; the second performs a one-way analysis of variance test. (Author/LRW)

Novel health monitoring method using an RGB camera.

PubMed

Hassan, M A; Malik, A S; Fofi, D; Saad, N; Meriaudeau, F

2017-11-01

In this paper we present a novel health monitoring method by estimating the heart rate and respiratory rate using an RGB camera. The heart rate and the respiratory rate are estimated from the photoplethysmography (PPG) and the respiratory motion. The method mainly operates by using the green spectrum of the RGB camera to generate a multivariate PPG signal to perform multivariate de-noising on the video signal to extract the resultant PPG signal. A periodicity based voting scheme (PVS) was used to measure the heart rate and respiratory rate from the estimated PPG signal. We evaluated our proposed method with a state of the art heart rate measuring method for two scenarios using the MAHNOB-HCI database and a self collected naturalistic environment database. The methods were furthermore evaluated for various scenarios at naturalistic environments such as a motion variance session and a skin tone variance session. Our proposed method operated robustly during the experiments and outperformed the state of the art heart rate measuring methods by compensating the effects of the naturalistic environment.

Design of instructions for evacuating disabled adults.

PubMed

Boyce, Michael W; Al-Awar Smither, Janan; Fisher, Daniel O; Hancock, P A

2017-01-01

We investigated how the design of instructions can affect performance in preparing emergency stair travel devices for the evacuation of disable individuals. We had three hypotheses: 1) Design of instructions would account for a significant portion of explained performance variance, 2) Improvements in design of instructions would reduce time on task across device type and age group, and 3) There would be a performance decrement for older adults compared to younger adults based on the slowing of older adult information processing abilities. Results showed that design of instructions does indeed account for a large portion of explained variance in the operation of emergency stair travel devices, and that improvements in design of instructions can reduce time on task across device type and age group. However, encouragingly for real-world operations, results did not indicate any significant differences between older versus younger adults. We look to explore ways that individuals with disabilities can exploit these insights to enhance the performance of emergency stair travel devices for use. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nurses' intentions to provide continuous labor support to women.

PubMed

Payant, Laura; Davies, Barbara; Graham, Ian D; Peterson, Wendy E; Clinch, Jennifer

2008-01-01

To examine the determinants of nurses' intentions to practice continuous labor support. A descriptive survey based on the Theory of Planned Behavior. A large, urban Canadian hospital with 2 sites and 7,000 births per year. Ninety-seven registered nurses from 2 birthing units. Scores measuring nurses' attitudes, subjective norms, and intentions regarding continuous labor support for women with epidural analgesia were significantly lower than those for women without epidural analgesia (p<.0001). Multiple regression analyses revealed that previous labor support courses, subjective norms, and perceived behavioral control explained 55% of the variance in nurses' intentions to provide continuous labor support to women without epidural analgesia while 88% of the variance in intentions to provide continuous labor support to women with epidural analgesia was explained by subjective norms and attitudes. Subjective norms made the most significant contribution to the variance in nurses' intentions to provide continuous labor support. Top perceived organizational barriers to continuous labor support included unit acuity and method of patient assignment. Nurses' intentions to provide continuous labor support are lower for women receiving epidural analgesia and are influenced by the perceived social pressures on their unit. Nurses view organizational barriers as important factors influencing their ability to provide continuous labor support.

From the front line to the bottom line: building revenue integrity.

PubMed

Britt, John; Adams, Shawn; Snow, Trevor

2015-07-01

To improve trends in accounts receivable and a hospital's bottom line without fear of penalty or repayment, organizations should expand the definition of the revenue cycle team by: Engaging front-line clinical and business personnel. Training personnel to understand the roles they play in revenue integrity. Creating scorecards with measurable goals to promote accountability. Monitoring the outcomes and defining real-time, actionable responses to negative variances.

Predictors of Language Gains Among School-Age Children With Language Impairment in the Public Schools.

PubMed

Justice, Laura M; Jiang, Hui; Logan, Jessica A; Schmitt, Mary Beth

2017-06-10

This study aimed to identify child-level characteristics that predict gains in language skills for children with language impairment who were receiving therapy within the public schools. The therapy provided represented business-as-usual speech/language treatment provided by speech-language pathologists in the public schools. The sample included 272 kindergartners and first-graders with language impairment who participated in a larger study titled "Speech-Therapy Experiences in the Public Schools." Multilevel regression analyses were applied to examine the extent to which select child-level characteristics, including age, nonverbal cognition, memory, phonological awareness, vocabulary, behavior problems, and self-regulation, predicted children's language gains over an academic year. Pratt indices were computed to establish the relative importance of the predictors of interest. Phonological awareness and vocabulary skill related to greater gains in language skills, and together they accounted for nearly 70% of the explained variance, or 10% of total variance at child level. Externalizing behavior, nonverbal cognition, and age were also potentially important predictors of language gains. This study significantly advances our understanding of the characteristics of children that may contribute to their language gains while receiving therapy in the public schools. Researchers can explore how these characteristics may serve to moderate treatment outcomes, whereas clinicians can assess how these characteristics may factor into understanding treatment responses.

Quality of life among Turkish immigrants in Sweden.

PubMed

Bayram, Nuran; Thorburn, Daniel; Demirhan, Haydar; Bilgel, Nazan

2007-10-01

To assess quality of life among Turkish immigrants in Sweden by using the WHOQOL-100 scale and to evaluate the domains' contribution to explain the variance in the quality of life of the immigrants. Our hypothesis was QOL among Turkish immigrants in Sweden are better than Turkish people who are living in their home country. This study was performed in the districts of Stockholm where Turkish immigrants have mostly settled. With the help and guidance of the Turkish Association, a sample of 520 participants was selected. We collected the demographic data by printed questionnaires, and to measure the quality of life, we used the WHOQOL-100 scale Turkish version. For analysis, we used the SPSS V.13.0 and R package programs, variance analyses, and Bayesian regression. The quality of life among the sample of Turkish immigrants was found to be moderate, but higher than the sample of the Turkish population. The quality of life of male immigrants was found to be higher than for females. Swedish-born Turks had better quality of life perceptions. Turkish immigrants' quality of life perceptions were better than those of the Turkish sample. The best scores were received from the third generation. The first generation and female immigrants need attention in order to receive higher quality of life perceptions.

Indoor radio channel modeling and mitigation of fading effects using linear and circular polarized antennas in combination for smart home system at 868 MHz

NASA Astrophysics Data System (ADS)

Wunderlich, S.; Welpot, M.; Gaspard, I.

2014-11-01

The markets for smart home products and services are expected to grow over the next years, driven by the increasing demands of homeowners considering energy monitoring, management, environmental controls and security. Many of these new systems will be installed in existing homes and offices and therefore using radio based systems for cost reduction. A drawback of radio based systems in indoor environments are fading effects which lead to a high variance of the received signal strength and thereby to a difficult predictability of the encountered path loss of the various communication links. For that reason it is necessary to derive a statistical path loss model which can be used to plan a reliable and cost effective radio network. This paper presents the results of a measurement campaign, which was performed in six buildings to deduce realistic radio channel models for a high variety of indoor radio propagation scenarios in the short range devices (SRD) band at 868 MHz. Furthermore, a potential concept to reduce the variance of the received signal strength using a circular polarized (CP) patch antenna in combination with a linear polarized antenna in an one-to-one communication link is presented.

Using Hierarchical Linear Modeling to Examine How Individual SLPs Differentially Contribute to Children's Language and Literacy Gains in Public Schools.

PubMed

Farquharson, Kelly; Tambyraja, Sherine R; Logan, Jessica; Justice, Laura M; Schmitt, Mary Beth

2015-08-01

The purpose of this study was twofold: (a) to determine the unique contributions in children's language and literacy gains, over 1 academic year, that are attributable to the individual speech-language pathologist (SLP) and (b) to explore possible child- and SLP-level factors that may further explain SLPs' contributions to children's language and literacy gains. Participants were 288 kindergarten and 1st-grade children with language impairment who were currently receiving school-based language intervention from SLPs. Using hierarchical linear modeling, we partitioned the variance in children's gains in language (i.e., grammar, vocabulary) and literacy (i.e., word decoding) that could be attributed to their individual SLP. Results revealed a significant contribution of individual SLPs to children's gains in grammar, vocabulary, and word decoding. Children's fall language scores and grade were significant predictors of SLPs' contributions, although no SLP-level predictors were significant. The present study makes a first step toward incorporating implementation science and suggests that, for children receiving school-based language intervention, variance in child language and literacy gains in an academic year is at least partially attributable to SLPs. Continued work in this area should examine the possible SLP-level characteristics that may further explicate the relative contributions of SLPs.

Audiometric correlates of the Hearing Handicap Inventory for the elderly.

PubMed

Weinstein, B E; Ventry, I M

1983-11-01

The self-assessment of hearing handicap has received considerable attention in recent years. The Hearing Handicap Inventory for the Elderly (HHIE) is a self-assessment technique designed to quantify the emotional and social effects of self-perceived hearing impairment in the noninstitutionalized elderly. The purpose of the present study was to examine the audiometric correlates of hearing handicap as measured by the HHIE. One hundred elderly subjects received complete audiometric evaluations as well as the HHIE. The results indicated that pure-tone sensitivity in the better ear was most highly correlated with the HHIE (r = .61) and that word recognition accounted for no more than 20% of the variance in HHIE scores. These results are similar to those reported for younger subjects and for other handicap assessment techniques. The results also indicated that there is considerable individual variability in the emotional and social response to hearing impairment, especially in individuals with mild (26-40 dB PTA in better ear) hearing impairment. The variability in response to impairment coupled with the fact that audiometric measures explain less than 50% of the variance in hearing handicap suggest that hearing handicap in the elderly will be measured more appropriately via a self-report format rather than as an inference from audiometric data.

Using negative emotional feedback to modify risky behavior of young moped riders.

PubMed

Megías, Alberto; Cortes, Abilio; Maldonado, Antonio; Cándido, Antonio

2017-05-19

The aim of this research was to investigate whether the use of messages with negative emotional content is effective in promoting safe behavior of moped riders and how exactly these messages modulate rider behavior. Participants received negative feedback when performing risky behaviors using a computer task. The effectiveness of this treatment was subsequently tested in a riding simulator. The results demonstrated how riders receiving negative feedback had a lower number of traffic accidents than a control group. The reduction in accidents was accompanied by a set of changes in the riding behavior. We observed a lower average speed and greater respect for speed limits. Furthermore, analysis of the steering wheel variance, throttle variance, and average braking force provided evidence for a more even and homogenous riding style. This greater abidance of traffic regulations and friendlier riding style could explain some of the causes behind the reduction in accidents. The use of negative emotional feedback in driving schools or advanced rider assistance systems could enhance riding performance, making riders aware of unsafe practices and helping them to establish more accurate riding habits. Moreover, the combination of riding simulators and feedback-for example, in the training of novice riders and traffic offenders-could be an efficient tool to improve their hazard perception skills and promote safer behaviors.

The Effects of Active Videogame Feedback and Practicing Experience on Children's Physical Activity Intensity and Enjoyment.

PubMed

Chen, Han; Sun, Haichun

2017-08-01

The study aims to explore the effects of receiving active videogame (AVG) feedback and playing experience on individuals' moderate-to-vigorous physical activity (MVPA) and perceived enjoyment. This was a within-subject design study. The participants included 36 (n = 15 and 21 for boys and girls, respectively) fourth graders enrolled in a rural elementary school in southern Georgia area. The experiment lasted for 6 weeks with each week including three sessions. The participants were assigned in either front row (sensor feedback) or back row (no sensor feedback) during practice, which was alternated in different sessions. Two different dance games were played during the study with each game implemented for 3 weeks. The MVPA was measured with GT3X+ accelerometers. Physical activity (PA) enjoyment was assessed after the completion of the first two and last two sessions of each game. A repeated one-way ANOVA (analysis of variance) was used to examine the effects of AVG feedback and game on MVPA. A repeated one-way MANOVA (multivariate analysis of variance) was conducted for each game to examine the effects of experience and AVG feedback on enjoyment and MVPA. No effects of AVG feedback were found for MVPA or enjoyment (P > 0.05). The effects of experience on MVPA were found for Just Dance Kids 2014 with experience decreased MVPA (P < 0.05). Students who practiced dance AVG without receiving feedback still demonstrated positive affection and accumulated similar MVPA than when practicing while receiving feedback. Experience for certain dance games tends to decrease PA intensity.

Radiant energy receiver having improved coolant flow control means

DOEpatents

Hinterberger, H.

1980-10-29

An improved coolant flow control for use in radiant energy receivers of the type having parallel flow paths is disclosed. A coolant performs as a temperature dependent valve means, increasing flow in the warmer flow paths of the receiver, and impeding flow in the cooler paths of the receiver. The coolant has a negative temperature coefficient of viscosity which is high enough such that only an insignificant flow through the receiver is experienced at the minimum operating temperature of the receiver, and such that a maximum flow is experienced at the maximum operating temperature of the receiver. The valving is accomplished by changes in viscosity of the coolant in response to the coolant being heated and cooled. No remotely operated valves, comparators or the like are needed.

Store-operate-coherence-on-value

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Dong; Heidelberger, Philip; Kumar, Sameer

A system, method and computer program product for performing various store-operate instructions in a parallel computing environment that includes a plurality of processors and at least one cache memory device. A queue in the system receives, from a processor, a store-operate instruction that specifies under which condition a cache coherence operation is to be invoked. A hardware unit in the system runs the received store-operate instruction. The hardware unit evaluates whether a result of the running the received store-operate instruction satisfies the condition. The hardware unit invokes a cache coherence operation on a cache memory address associated with the receivedmore » store-operate instruction if the result satisfies the condition. Otherwise, the hardware unit does not invoke the cache coherence operation on the cache memory device.« less

A Minimum Variance Algorithm for Overdetermined TOA Equations with an Altitude Constraint.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Romero, Louis A; Mason, John J.

We present a direct (non-iterative) method for solving for the location of a radio frequency (RF) emitter, or an RF navigation receiver, using four or more time of arrival (TOA) measurements and an assumed altitude above an ellipsoidal earth. Both the emitter tracking problem and the navigation application are governed by the same equations, but with slightly different interpreta- tions of several variables. We treat the assumed altitude as a soft constraint, with a specified noise level, just as the TOA measurements are handled, with their respective noise levels. With 4 or more TOA measurements and the assumed altitude, themore » problem is overdetermined and is solved in the weighted least squares sense for the 4 unknowns, the 3-dimensional position and time. We call the new technique the TAQMV (TOA Altitude Quartic Minimum Variance) algorithm, and it achieves the minimum possible error variance for given levels of TOA and altitude estimate noise. The method algebraically produces four solutions, the least-squares solution, and potentially three other low residual solutions, if they exist. In the lightly overdermined cases where multiple local minima in the residual error surface are more likely to occur, this algebraic approach can produce all of the minima even when an iterative approach fails to converge. Algorithm performance in terms of solution error variance and divergence rate for bas eline (iterative) and proposed approach are given in tables.« less

Does Intraspecific Size Variation in a Predator Affect Its Diet Diversity and Top-Down Control of Prey?

PubMed Central

Ingram, Travis; Stutz, William E.; Bolnick, Daniel I.

2011-01-01

It has long been known that intraspecific variation impacts evolutionary processes, but only recently have its potential ecological effects received much attention. Theoretical models predict that genetic or phenotypic variance within species can alter interspecific interactions, and experiments have shown that genotypic diversity in clonal species can impact a wide range of ecological processes. To extend these studies to quantitative trait variation within populations, we experimentally manipulated the variance in body size of threespine stickleback in enclosures in a natural lake environment. We found that body size of stickleback in the lake is correlated with prey size and (to a lesser extent) composition, and that stickleback can exert top-down control on their benthic prey in enclosures. However, a six-fold contrast in body size variance had no effect on the degree of diet variation among individuals, or on the abundance or composition of benthic or pelagic prey. Interestingly, post-hoc analyses revealed suggestive correlations between the degree of diet variation and the strength of top-down control by stickleback. Our negative results indicate that, unless the correlation between morphology and diet is very strong, ecological variation among individuals may be largely decoupled from morphological variance. Consequently we should be cautious in our interpretation both of theoretical models that assume perfect correlations between morphology and diet, and of empirical studies that use morphological variation as a proxy for resource use diversity. PMID:21687670

Does intraspecific size variation in a predator affect its diet diversity and top-down control of prey?

PubMed

Ingram, Travis; Stutz, William E; Bolnick, Daniel I

2011-01-01

It has long been known that intraspecific variation impacts evolutionary processes, but only recently have its potential ecological effects received much attention. Theoretical models predict that genetic or phenotypic variance within species can alter interspecific interactions, and experiments have shown that genotypic diversity in clonal species can impact a wide range of ecological processes. To extend these studies to quantitative trait variation within populations, we experimentally manipulated the variance in body size of threespine stickleback in enclosures in a natural lake environment. We found that body size of stickleback in the lake is correlated with prey size and (to a lesser extent) composition, and that stickleback can exert top-down control on their benthic prey in enclosures. However, a six-fold contrast in body size variance had no effect on the degree of diet variation among individuals, or on the abundance or composition of benthic or pelagic prey. Interestingly, post-hoc analyses revealed suggestive correlations between the degree of diet variation and the strength of top-down control by stickleback. Our negative results indicate that, unless the correlation between morphology and diet is very strong, ecological variation among individuals may be largely decoupled from morphological variance. Consequently we should be cautious in our interpretation both of theoretical models that assume perfect correlations between morphology and diet, and of empirical studies that use morphological variation as a proxy for resource use diversity.

Accuracy of WAAS-Enabled GPS-RF Warning Signals When Crossing a Terrestrial Geofence

PubMed Central

Grayson, Lindsay M.; Keefe, Robert F.; Tinkham, Wade T.; Eitel, Jan U. H.; Saralecos, Jarred D.; Smith, Alistair M. S.; Zimbelman, Eloise G.

2016-01-01

Geofences are virtual boundaries based on geographic coordinates. When combined with global position system (GPS), or more generally global navigation satellite system (GNSS) transmitters, geofences provide a powerful tool for monitoring the location and movements of objects of interest through proximity alarms. However, the accuracy of geofence alarms in GNSS-radio frequency (GNSS-RF) transmitter receiver systems has not been tested. To achieve these goals, a cart with a GNSS-RF locator was run on a straight path in a balanced factorial experiment with three levels of cart speed, three angles of geofence intersection, three receiver distances from the track, and three replicates. Locator speed, receiver distance and geofence intersection angle all affected geofence alarm accuracy in an analysis of variance (p = 0.013, p = 2.58 × 10−8, and p = 0.0006, respectively), as did all treatment interactions (p < 0.0001). Slower locator speed, acute geofence intersection angle, and closest receiver distance were associated with reduced accuracy of geofence alerts. PMID:27322287

Accuracy of WAAS-Enabled GPS-RF Warning Signals When Crossing a Terrestrial Geofence.

PubMed

Grayson, Lindsay M; Keefe, Robert F; Tinkham, Wade T; Eitel, Jan U H; Saralecos, Jarred D; Smith, Alistair M S; Zimbelman, Eloise G

2016-06-18

Geofences are virtual boundaries based on geographic coordinates. When combined with global position system (GPS), or more generally global navigation satellite system (GNSS) transmitters, geofences provide a powerful tool for monitoring the location and movements of objects of interest through proximity alarms. However, the accuracy of geofence alarms in GNSS-radio frequency (GNSS-RF) transmitter receiver systems has not been tested. To achieve these goals, a cart with a GNSS-RF locator was run on a straight path in a balanced factorial experiment with three levels of cart speed, three angles of geofence intersection, three receiver distances from the track, and three replicates. Locator speed, receiver distance and geofence intersection angle all affected geofence alarm accuracy in an analysis of variance (p = 0.013, p = 2.58 × 10(-8), and p = 0.0006, respectively), as did all treatment interactions (p < 0.0001). Slower locator speed, acute geofence intersection angle, and closest receiver distance were associated with reduced accuracy of geofence alerts.

Visible scintillation photodetector device incorporating chalcopyrite semiconductor crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stowe, Ashley C.; Burger, Arnold

2017-04-04

A photodetector device, including: a scintillator material operable for receiving incident radiation and emitting photons in response; a photodetector material coupled to the scintillator material operable for receiving the photons emitted by the scintillator material and generating a current in response, wherein the photodetector material includes a chalcopyrite semiconductor crystal; and a circuit coupled to the photodetector material operable for characterizing the incident radiation based on the current generated by the photodetector material. Optionally, the scintillator material includes a gamma scintillator material and the incident radiation received includes gamma rays. Optionally, the photodetector material is further operable for receiving thermalmore » neutrons and generating a current in response. The circuit is further operable for characterizing the thermal neutrons based on the current generated by the photodetector material.« less

25 CFR 543.18 - What are the minimum internal control standards for the cage, vault, kiosk, cash and cash...

Code of Federal Regulations, 2014 CFR

2014-04-01

... available upon demand for each day, shift, and drop cycle (this is not required if the system does not track..., beverage containers, etc., into and out of the cage. (j) Variances. The operation must establish, as...

25 CFR 543.18 - What are the minimum internal control standards for the cage, vault, kiosk, cash and cash...

Code of Federal Regulations, 2013 CFR

2013-04-01

... available upon demand for each day, shift, and drop cycle (this is not required if the system does not track..., beverage containers, etc., into and out of the cage. (j) Variances. The operation must establish, as...

Hierarchical Bayesian modeling of heterogeneous variances in average daily weight gain of commercial feedlot cattle.

PubMed

Cernicchiaro, N; Renter, D G; Xiang, S; White, B J; Bello, N M

2013-06-01

Variability in ADG of feedlot cattle can affect profits, thus making overall returns more unstable. Hence, knowledge of the factors that contribute to heterogeneity of variances in animal performance can help feedlot managers evaluate risks and minimize profit volatility when making managerial and economic decisions in commercial feedlots. The objectives of the present study were to evaluate heteroskedasticity, defined as heterogeneity of variances, in ADG of cohorts of commercial feedlot cattle, and to identify cattle demographic factors at feedlot arrival as potential sources of variance heterogeneity, accounting for cohort- and feedlot-level information in the data structure. An operational dataset compiled from 24,050 cohorts from 25 U. S. commercial feedlots in 2005 and 2006 was used for this study. Inference was based on a hierarchical Bayesian model implemented with Markov chain Monte Carlo, whereby cohorts were modeled at the residual level and feedlot-year clusters were modeled as random effects. Forward model selection based on deviance information criteria was used to screen potentially important explanatory variables for heteroskedasticity at cohort- and feedlot-year levels. The Bayesian modeling framework was preferred as it naturally accommodates the inherently hierarchical structure of feedlot data whereby cohorts are nested within feedlot-year clusters. Evidence for heterogeneity of variance components of ADG was substantial and primarily concentrated at the cohort level. Feedlot-year specific effects were, by far, the greatest contributors to ADG heteroskedasticity among cohorts, with an estimated ∼12-fold change in dispersion between most and least extreme feedlot-year clusters. In addition, identifiable demographic factors associated with greater heterogeneity of cohort-level variance included smaller cohort sizes, fewer days on feed, and greater arrival BW, as well as feedlot arrival during summer months. These results support that heterogeneity of variances in ADG is prevalent in feedlot performance and indicate potential sources of heteroskedasticity. Further investigation of factors associated with heteroskedasticity in feedlot performance is warranted to increase consistency and uniformity in commercial beef cattle production and subsequent profitability.

[Management of patients with bronchial asthma received general anesthesia and surgical intervention].

PubMed

To, Masako; Tajima, Makoto; Ogawa, Cyuhei; Otomo, Mamoru; Suzuki, Naohito; Sano, Yasuyuki

2002-01-01

Stimulation to bronchial mucosa is one of the major risk factor of asthma attack. When patients receive surgical intervention and general anesthesia, they are always exposed to stimulation to bronchial mucosa. Prevention method of bronchial asthma attack during surgical intervention is not established yet. We investigated that clinical course of patients with bronchial asthma who received general anesthesia and surgical intervention. Seventy-six patients with bronchial asthma were received general anesthesia and surgical intervention from 1993 to 1998. Twenty-four patients were mild asthmatic patients, 39 were moderate asthmatic patients and 13 were severe asthmatic patients. Preoperative treatment for preventing asthma attack was as follows; Eight patients were given intravenous infusion of aminophylline before operation. Fifty-two patients were given intravenous infusion of aminophylline and hydrocortisone before operation. Three patients were given intravenous infusion of hydrocortisone for consecutive 3 days before operation. Thirteen patients were given no treatment for preventing asthma attack. One patient was suffered from asthma attack during operation. She was given no preventing treatment for asthma attack before operation. Three patients were suffered from asthma attack after operation. No wound dehiscence was observed in all patients. To prevent asthma attack during operation, intravenous infusion of steroid before operation is recommended, when patients with asthma receive general anesthesia and surgical intervention.

Optical double-locked semiconductor lasers

NASA Astrophysics Data System (ADS)

AlMulla, Mohammad

2018-06-01

Self-sustained period-one (P1) nonlinear dynamics of a semiconductor laser are investigated when both optical injection and modulation are applied for stable microwave frequency generation. Locking the P1 oscillation through modulation on the bias current, injection strength, or detuning frequency stabilizes the P1 oscillation. Through the phase noise variance, the different modulation types are compared. It is demonstrated that locking the P1 oscillation through optical modulation on the output of the master laser outperforms bias-current modulation of the slave laser. Master laser modulation shows wider P1-oscillation locking range and lower phase noise variance. The locking characteristics of the P1 oscillation also depend on the operating conditions of the optical injection system

Bootstrap-based procedures for inference in nonparametric receiver-operating characteristic curve regression analysis.

PubMed

Rodríguez-Álvarez, María Xosé; Roca-Pardiñas, Javier; Cadarso-Suárez, Carmen; Tahoces, Pablo G

2018-03-01

Prior to using a diagnostic test in a routine clinical setting, the rigorous evaluation of its diagnostic accuracy is essential. The receiver-operating characteristic curve is the measure of accuracy most widely used for continuous diagnostic tests. However, the possible impact of extra information about the patient (or even the environment) on diagnostic accuracy also needs to be assessed. In this paper, we focus on an estimator for the covariate-specific receiver-operating characteristic curve based on direct regression modelling and nonparametric smoothing techniques. This approach defines the class of generalised additive models for the receiver-operating characteristic curve. The main aim of the paper is to offer new inferential procedures for testing the effect of covariates on the conditional receiver-operating characteristic curve within the above-mentioned class. Specifically, two different bootstrap-based tests are suggested to check (a) the possible effect of continuous covariates on the receiver-operating characteristic curve and (b) the presence of factor-by-curve interaction terms. The validity of the proposed bootstrap-based procedures is supported by simulations. To facilitate the application of these new procedures in practice, an R-package, known as npROCRegression, is provided and briefly described. Finally, data derived from a computer-aided diagnostic system for the automatic detection of tumour masses in breast cancer is analysed.

Use of linear programming to estimate impact of changes in a hospital's operating room time allocation on perioperative variable costs.

PubMed

Dexter, Franklin; Blake, John T; Penning, Donald H; Sloan, Brian; Chung, Patricia; Lubarsky, David A

2002-03-01

Administrators at hospitals with a fixed annual budget may want to focus surgical services on priority areas to ensure its community receives the best health services possible. However, many hospitals lack the detailed managerial accounting data needed to ensure that such a change does not increase operating costs. The authors used a detailed hospital cost database to investigate by how much a change in allocations of operating room (OR) time among surgeons can increase perioperative variable costs. The authors obtained financial data for all patients who underwent outpatient or same-day admit surgery during a year. Linear programming was used to determine by how much changing the mix of surgeons can increase total variable costs while maintaining the same total hours of OR time for elective cases. Changing OR allocations among surgeons without changing total OR hours allocated will likely increase perioperative variable costs by less than 34%. If, in addition, intensive care unit hours for elective surgical cases are not increased, hospital ward occupancy is capped, and implant use is tracked and capped, perioperative costs will likely increase by less than 10%. These four variables predict 97% of the variance in total variable costs. The authors showed that changing OR allocations among surgeons without changing total OR hours allocated can increase hospital perioperative variable costs by up to approximately one third. Thus, at hospitals with fixed or nearly fixed annual budgets, allocating OR time based on an OR-based statistic such as utilization can adversely affect the hospital financially. The OR manager can reduce the potential increase in costs by considering not just OR time, but also the resulting use of hospital beds and implants.

A key heterogeneous structure of fractal networks based on inverse renormalization scheme

NASA Astrophysics Data System (ADS)

Bai, Yanan; Huang, Ning; Sun, Lina

2018-06-01

Self-similarity property of complex networks was found by the application of renormalization group theory. Based on this theory, network topologies can be classified into universality classes in the space of configurations. In return, through inverse renormalization scheme, a given primitive structure can grow into a pure fractal network, then adding different types of shortcuts, it exhibits different characteristics of complex networks. However, the effect of primitive structure on networks structural property has received less attention. In this paper, we introduce a degree variance index to measure the dispersion of nodes degree in the primitive structure, and investigate the effect of the primitive structure on network structural property quantified by network efficiency. Numerical simulations and theoretical analysis show a primitive structure is a key heterogeneous structure of generated networks based on inverse renormalization scheme, whether or not adding shortcuts, and the network efficiency is positively correlated with degree variance of the primitive structure.

High stability lasers for lidar and remote sensing

NASA Astrophysics Data System (ADS)

Heine, Frank; Lange, Robert; Seel, Stefan; Smutny, Berry

2017-11-01

Tesat-Spacecom is currently building a set flight models of frequency stabilized lasers for the ESA Missions AEOLUS and LTP. Lasers with low intensity noise in the kHz region and analogue tuning capabilities for frequency and output power are developed for the on board metrology of the LTP project, the precursor mission for LISA. This type of laser is internally stabilized by precise temperature control, approaching an ALLAN variance of 10-9 for 100 sec. It can be easily locked to external frequency references with <50kHz bandwidth. The Seed laser for the AEOLUS mission (wind LIDAR) is used as the master frequency reference and is stabilized internally by a optical cavity. It shows a 3* 10-11 Allan variance from time intervals 1 sec - 1000 sec. Furthermore it is step-tunable for calibration of the receiver instrument with a speed of GHz / sec by a digital command interface. Performance and environmental test results will be presented.

Quantifying the uncertainty in heritability

PubMed Central

Furlotte, Nicholas A; Heckerman, David; Lippert, Christoph

2014-01-01

The use of mixed models to determine narrow-sense heritability and related quantities such as SNP heritability has received much recent attention. Less attention has been paid to the inherent variability in these estimates. One approach for quantifying variability in estimates of heritability is a frequentist approach, in which heritability is estimated using maximum likelihood and its variance is quantified through an asymptotic normal approximation. An alternative approach is to quantify the uncertainty in heritability through its Bayesian posterior distribution. In this paper, we develop the latter approach, make it computationally efficient and compare it to the frequentist approach. We show theoretically that, for a sufficiently large sample size and intermediate values of heritability, the two approaches provide similar results. Using the Atherosclerosis Risk in Communities cohort, we show empirically that the two approaches can give different results and that the variance/uncertainty can remain large. PMID:24670270

Multivariate Models of Men's and Women's Partner Aggression

ERIC Educational Resources Information Center

O'Leary, K. Daniel; Smith Slep, Amy M.; O'Leary, Susan G.

2007-01-01

This exploratory study was designed to address how multiple factors drawn from varying focal models and ecological levels of influence might operate relative to each other to predict partner aggression, using data from 453 representatively sampled couples. The resulting cross-validated models predicted approximately 50% of the variance in men's…

29 CFR 1956.43 - Developmental schedule.

Code of Federal Regulations, 2010 CFR

2010-07-01

... as provided by the plan: (a) A new State poster will be printed, by December 15, 1978, in order to... part 1905 (Variance Rules); 29 CFR part 2200 (Review Commission); and the Field Operations Manual. (d... employees are covered by the plan, giving the number of employees for each entity, describing the work...

47 CFR 73.691 - Visual modulation monitoring.

Code of Federal Regulations, 2010 CFR

2010-10-01

... must have measuring equipment for determining that the transmitted visual signal conforms to the... a period of not more than 30 days without specific authority from the FCC: provided that, the date... operation at variance will exceed 10 consecutive days, a notification must be sent to the FCC in Washington...

Survey of Munitions Response Technologies

DTIC Science & Technology

2006-06-01

3-34 3.3.4 Digital Data Processing .......................................................................... 3-36 4.0 SOURCE DATA AND METHODS...6-4 6.1.6 DGM versus Mag and Flag Processes ..................................................... 6-5 6.1.7 Translation to...signatures, surface clutter, variances in operator technique, target selection, and data processing all degrade from and affect optimum performance

Maslow's Need Hierarchy Related to Educational Attitudes and Self-Concepts of Elementary Student Teachers.

ERIC Educational Resources Information Center

Noad, Brian

1979-01-01

The Work Motivation Inventory, Minnesota Teacher Attitude Inventory, and Adjective Self Description Instrument were administered to 128 University of Houston student teachers. Results indicated that educational attitudes and self-concept, operating jointly, significantly contributed to the variance in Maslow's scales of basic, safety, and…

Reputational Challenges for Business Schools: A Contextual Perspective

ERIC Educational Resources Information Center

Siebert, Sabina; Martin, Graeme

2013-01-01

Purpose: The dominant variance theory approaches to researching business school reputations are based on a positivistic hypothetico-deductive research methodology and do not adequately take into account either the different levels and types of contexts in which business schools operate or the diversity of stakeholder interests. The aim of this…

78 FR 20035 - Adequacy of Oregon Municipal Solid Waste Landfill Permit Program

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-03

... to issue Research, Development, and Demonstration (RD&D) Permits to owners and operators of MSWLF... Landfill (MSWLF) criteria in 40 CFR part 258 to allow Research, Development, and Demonstration (RD&D... authority for variance of criteria for groundwater monitoring, closure and post-closure requirements (except...

The Comstar D/3 gain degradation experiment

NASA Technical Reports Server (NTRS)

Lee, T. C.; Hodge, D. B.

1981-01-01

The results of gain degradation measurements using the Comstar D/3 19.04 GHz beacon are reported. This experiment utilized 0.6 and 5 m aperture antennas aligned along the same propagation path to examine propagation effects which are related to the antenna aperture size. Sample data for clear air, scintillation in clear air, and precipitation fading are presented. Distributions of the received signal levels and variances for both antennas are also presented.

Navy Ship Names: Background for Congress

DTIC Science & Technology

2016-09-14

Secretary considers these nominations , along with others he receives as well as his own thoughts in this matter. At appropriate times, he selects names...Research Service 16 “ nomination ” process is often fiercely contested as differing groups make the case that “their” ship name is the most fitting...and practices of the Navy for naming vessels of the Navy, and an explanation for such variances;  Assesses the feasibility and advisability of

Forty-five-degree or higher insertion angles are required to penetrate the opposite cortex in bicortical applications of Kirschner wires: an in vitro study on sheep bones.

PubMed

Colak, Mehmet; Gurer, Burak; Sungur, Mehmet Ali; Eskandari, Metin Manouchehr

2012-04-01

Slippage of the wires over the opposite cortex from the endosteal side is frequent and can lead to insufficient stability. This in vitro biomechanical study was planned to investigate the angle of wire insertion that leads to trans cortex perforation. Long bones of sheep were cut longitudinally into two pieces and half bones were stabilised on a frame. Three orthopaedic surgeons performed the experiment using ten wires of four different diameters at two different drilling speeds. Each wire was introduced from the endosteal side at angles starting at 30° in 5° increments until perforation. When perforation was achieved, the angle was recorded. To determinate the critical angle of perforation, receiver operating characteristic (ROC) curve analyses was performed. Two-way factorial analysis of variance (ANOVA) and Kruskal-Wallis tests were used for statistical comparisons. Kirschner-wire insertion angles of ≥ 45° provided perforation with a percentage of 83.9 %. Wire diameter, drilling speed and surgeon variables had no effect on perforation angles (p > 0.05). If preoperative evaluation of fractures to be fixed by K wires reveals the need for oblique wire insertion angle < 45°, a standard trocar-tip K wire application would lead to slippage of the wire tip on the endosteal surface of the opposite cortex. According to this study, the operative plan should be changed if such obliquity of the K wire is mandatory during bicortical applications.

Prostate cancer survivors with a passive role preference in treatment decision-making are less satisfied with information received: Results from the PROFILES registry.

PubMed

Cuypers, Maarten; Lamers, Romy E D; de Vries, Marieke; Husson, Olga; Kil, Paul J M; van de Poll-Franse, Lonneke V

2016-11-01

To investigate decision-making role preferences and their association with the evaluation of information received in a sample of low-risk and intermediate-risk prostate cancer (Pca) survivors. Cross-sectional study involved 562 men diagnosed with low-risk or intermediate-risk Pca (median time since diagnosis, 48mo), measuring preferred decision-making role (Control Preference Scale) and the evaluation of information received (EORTC QLQ-INFO25). Analyses were performed using analysis of variance, chi-square tests, and multivariable linear regression models. Men who preferred a passive role were older and less educated than other preference groups and more often selected a noninvasive treatment option (all with P<0.001). The passive role preference group reported having received less information, judged the received information as less helpful, and indicated lower overall satisfaction with information received (all with P<0.05). Role preference groups did not differ in their desire to receive more information. Compared with nonpassive preference groups, the preference for a passive role in Pca treatment decision-making is associated with less satisfaction with the information received. Assessment of role preferences and tailored information provision could improve satisfaction with information received and perhaps may ultimately lead to improved patient participation in treatment decision-making. Copyright © 2016 Elsevier Inc. All rights reserved.

Spatial and visuospatial working memory tests predict performance in classic multiple-object tracking in young adults, but nonspatial measures of the executive do not.

PubMed

Trick, Lana M; Mutreja, Rachna; Hunt, Kelly

2012-02-01

An individual-differences approach was used to investigate the roles of visuospatial working memory and the executive in multiple-object tracking. The Corsi Blocks and Visual Patterns Tests were used to assess visuospatial working memory. Two relatively nonspatial measures of the executive were used: operation span (OSPAN) and reading span (RSPAN). For purposes of comparison, the digit span test was also included (a measure not expected to correlate with tracking). The tests predicted substantial amounts of variance (R (2) = .33), and the visuospatial measures accounted for the majority (R (2) = .30), with each making a significant contribution. Although the executive measures correlated with each other, the RSPAN did not correlate with tracking. The correlation between OSPAN and tracking was similar in magnitude to that between digit span and tracking (p < .05 for both), and when regression was used to partial out shared variance between the two tests, the remaining variance predicted by the OSPAN was minimal (sr ( 2 ) = .029). When measures of spatial memory were included in the regression, the unique variance predicted by the OSPAN became negligible (sr ( 2 ) = .000004). This suggests that the executive, as measured by tests such as the OSPAN, plays little role in explaining individual differences in multiple-object tracking.

Send-side matching of data communications messages

DOEpatents

Archer, Charles J.; Blocksome, Michael A.; Ratterman, Joseph D.; Smith, Brian E.

2014-06-17

Send-side matching of data communications messages in a distributed computing system comprising a plurality of compute nodes, including: issuing by a receiving node to source nodes a receive message that specifies receipt of a single message to be sent from any source node, the receive message including message matching information, a specification of a hardware-level mutual exclusion device, and an identification of a receive buffer; matching by two or more of the source nodes the receive message with pending send messages in the two or more source nodes; operating by one of the source nodes having a matching send message the mutual exclusion device, excluding messages from other source nodes with matching send messages and identifying to the receiving node the source node operating the mutual exclusion device; and sending to the receiving node from the source node operating the mutual exclusion device a matched pending message.

Molecular characterization of soil bacterial community in a perhumid, low mountain forest.

PubMed

Lin, Yu-Te; Whitman, William B; Coleman, David C; Chih-Yu, Chiu

2011-01-01

Forest disturbance often results in changes in soil properties and microbial communities. In the present study, we characterized a soil bacterial community subjected to disturbance using 16S rRNA gene clone libraries. The community was from a disturbed broad-leaved, low mountain forest ecosystem at Huoshaoliao (HSL) located in northern Taiwan. This locality receives more than 4,000 mm annual precipitation, one of the highest precipitations in Taiwan. Based on the Shannon diversity index, Chao1 estimator, richness and rarefaction curve analysis, the bacterial community in HSL forest soils was more diverse than those previously investigated in natural and disturbed forest soils with colder or less humid weather conditions. Analysis of molecular variance also revealed that the bacterial community in disturbed soils significantly differed from natural forest soils. Most of the abundant operational taxonomic units (OTUs) in the disturbed soil community at HSL were less abundant or absent in other soils. The disturbances influenced the composition of bacterial communities in natural and disturbed forests and increased the diversity of the disturbed forest soil community. Furthermore, the warmer and humid weather conditions could also increase community diversity in HSL soils.

Factors affecting unsafe behavior in construction projects: development and validation of a new questionnaire.

PubMed

Asilian-Mahabadi, Hassan; Khosravi, Yahya; Hassanzadeh-Rangi, Narmin; Hajizadeh, Ebrahim; Behzadan, Amir H

2018-02-05

Occupational safety in general, and construction safety in particular, is a complex phenomenon. This study was designed to develop a new valid measure to evaluate factors affecting unsafe behavior in the construction industry. A new questionnaire was generated from qualitative research according to the principles of grounded theory. Key measurement properties (face validity, content validity, construct validity, reliability and discriminative validity) were examined using qualitative and quantitative approaches. The receiver operating characteristic curve was used to estimate the discriminating power and the optimal cutoff score. Construct validity revealed an interpretable 12-factor structure which explained 61.87% of variance. Good internal consistency (Cronbach's α = 0.94) and stability (intra-class correlation coefficient = 0.93) were found for the new instrument. The area under the curve, sensitivity and specificity were 0.80, 0.80 and 0.75, respectively. The new instrument also discriminated safety performance among the construction sites with different workers' accident histories (F = 6.40, p < 0.05). The new instrument appears to be a valid, reliable and sensitive instrument that will contribute to investigating the root causes of workers' unsafe behaviors, thus promoting safety performance in the construction industry.

Detection of periimplant fenestration and dehiscence with the use of two scan modes and the smallest voxel sizes of a cone-beam computed tomography device.

PubMed

de-Azevedo-Vaz, Sergio Lins; Vasconcelos, Karla de Faria; Neves, Frederico Sampaio; Melo, Saulo Leonardo Sousa; Campos, Paulo Sérgio Flores; Haiter-Neto, Francisco

2013-01-01

To assess the accuracy of cone-beam computed tomography (CBCT) in periimplant fenestration and dehiscence detection, and to determine the effects of 2 voxel sizes and scan modes. One hundred titanium implants were placed in bovine ribs in which periimplant fenestration and dehiscence were simulated. CBCT images were acquired with the use of 3 protocols of the i-CAT NG unit: A) 0.2 mm voxel size half-scan (180°); B) 0.2 mm voxel size full-scan (360°); and C) 0.12 mm voxel size full scan (360°). Receiver operating characteristic curves and diagnostic values were obtained. The Az values were compared with the use of analysis of variance. The Az value for dehiscence in protocol A was significantly lower than those of B or C (P < .01). They did not statistically differ for fenestration (P > .05). Protocol B yielded the highest values. The voxel sizes did not affect fenestration and dehiscence detection, and for dehiscence full-scan performed better than half-scan. Copyright © 2013 Elsevier Inc. All rights reserved.

Deficient symbol processing in Alzheimer disease.

PubMed

Toepper, Max; Steuwe, Carolin; Beblo, Thomas; Bauer, Eva; Boedeker, Sebastian; Thomas, Christine; Markowitsch, Hans J; Driessen, Martin; Sammer, Gebhard

2014-01-01

Symbols and signs have been suggested to improve the orientation of patients suffering from Alzheimer disease (AD). However, there are hardly any studies that confirm whether AD patients benefit from signs or symbols and which symbol characteristics might improve or impede their symbol comprehension. To address these issues, 30 AD patients and 30 matched healthy controls performed a symbol processing task (SPT) with 4 different item categories. A repeated-measures analysis of variance was run to identify impact of different item categories on performance accuracy in both the experimental groups. Moreover, SPT scores were correlated with neuropsychological test scores in a broad range of other cognitive domains. Finally, diagnostic accuracy of the SPT was calculated by a receiver-operating characteristic curve analysis. Results revealed a global symbol processing dysfunction in AD that was associated with semantic memory and executive deficits. Moreover, AD patients showed a disproportional performance decline at SPT items with visual distraction. Finally, the SPT total score showed high sensitivity and specificity in differentiating between AD patients and healthy controls. The present findings suggest that specific symbol features impede symbol processing in AD and argue for a diagnostic benefit of the SPT in neuropsychological assessment.

Laboratory test variables useful for distinguishing upper from lower gastrointestinal bleeding.

PubMed

Tomizawa, Minoru; Shinozaki, Fuminobu; Hasegawa, Rumiko; Shirai, Yoshinori; Motoyoshi, Yasufumi; Sugiyama, Takao; Yamamoto, Shigenori; Ishige, Naoki

2015-05-28

To distinguish upper from lower gastrointestinal (GI) bleeding. Patient records between April 2011 and March 2014 were analyzed retrospectively (3296 upper endoscopy, and 1520 colonoscopy). Seventy-six patients had upper GI bleeding (Upper group) and 65 had lower GI bleeding (Lower group). Variables were compared between the groups using one-way analysis of variance. Logistic regression was performed to identify variables significantly associated with the diagnosis of upper vs lower GI bleeding. Receiver-operator characteristic (ROC) analysis was performed to determine the threshold value that could distinguish upper from lower GI bleeding. Hemoglobin (P = 0.023), total protein (P = 0.0002), and lactate dehydrogenase (P = 0.009) were significantly lower in the Upper group than in the Lower group. Blood urea nitrogen (BUN) was higher in the Upper group than in the Lower group (P = 0.0065). Logistic regression analysis revealed that BUN was most strongly associated with the diagnosis of upper vs lower GI bleeding. ROC analysis revealed a threshold BUN value of 21.0 mg/dL, with a specificity of 93.0%. The threshold BUN value for distinguishing upper from lower GI bleeding was 21.0 mg/dL.

Laboratory test variables useful for distinguishing upper from lower gastrointestinal bleeding

PubMed Central

Tomizawa, Minoru; Shinozaki, Fuminobu; Hasegawa, Rumiko; Shirai, Yoshinori; Motoyoshi, Yasufumi; Sugiyama, Takao; Yamamoto, Shigenori; Ishige, Naoki

2015-01-01

AIM: To distinguish upper from lower gastrointestinal (GI) bleeding. METHODS: Patient records between April 2011 and March 2014 were analyzed retrospectively (3296 upper endoscopy, and 1520 colonoscopy). Seventy-six patients had upper GI bleeding (Upper group) and 65 had lower GI bleeding (Lower group). Variables were compared between the groups using one-way analysis of variance. Logistic regression was performed to identify variables significantly associated with the diagnosis of upper vs lower GI bleeding. Receiver-operator characteristic (ROC) analysis was performed to determine the threshold value that could distinguish upper from lower GI bleeding. RESULTS: Hemoglobin (P = 0.023), total protein (P = 0.0002), and lactate dehydrogenase (P = 0.009) were significantly lower in the Upper group than in the Lower group. Blood urea nitrogen (BUN) was higher in the Upper group than in the Lower group (P = 0.0065). Logistic regression analysis revealed that BUN was most strongly associated with the diagnosis of upper vs lower GI bleeding. ROC analysis revealed a threshold BUN value of 21.0 mg/dL, with a specificity of 93.0%. CONCLUSION: The threshold BUN value for distinguishing upper from lower GI bleeding was 21.0 mg/dL. PMID:26034359

Spatial and seasonal distribution of adult Oithona similis in the Southern Ocean: Predictions using boosted regression trees

NASA Astrophysics Data System (ADS)

Pinkerton, Matt H.; Smith, Adam N. H.; Raymond, Ben; Hosie, Graham W.; Sharp, Ben; Leathwick, John R.; Bradford-Grieve, Janet M.

2010-04-01

We applied a multivariate statistical modelling technique called boosted regression trees to derive relationships between environmental conditions and the distribution of the adult stage of the cyclopoid copepod Oithona similis in the Southern Ocean. Nearly 20 000 samples from the Southern Ocean Continuous Plankton Recorder survey (87% from East Antarctica) were used to model the probability of detection (presence) and relative abundance of adults of this zooplankton species in surface waters. We demonstrate that it is possible to obtain reasonable models for both the presence (area under the Receiver Operating Characteristic curve of 0.77) and relative abundance (28-35% variance explained) of adult O. similis between November and March in much of the Southern Ocean. No investigation was possible where the environmental characteristics were not well represented by the SO-CPR dataset, namely, the Argentine shelf, Weddell Sea, and the frontal region north of the Amundsen Sea, or under sea-ice. Our analyses support the hypothesis that adult O. similis abundance is related to environmental conditions in a broadly similar way throughout the Southern Ocean. Compared to a compilation of net-haul data from the literature, the abundance model explained 34% of the variance in surface concentrations of adult stages of this species, and 23-59% of the variance in depth-integrated abundance of copepodite and adult stages combined. The models show higher occurrence and elevated abundances in a broad circumpolar band between the Antarctic Polar Front and the southern boundary of the Antarctic Circumpolar Current (approximately 54-64°S). Evidence of diel vertical migration by adults of this species north of 65°S was found, with surface abundances 20% higher at night than during the day. There was no evidence of diel migration south of 65°S. Five potential "hotspots" of adult O. similis were identified: in the southern Scotia Sea, two areas off east Antarctica, in the frontal zone north of the Amundsen Sea, and a small area in the outer Bellingshausen Sea. We recommend that a database of all available net-haul data on Oithona similis in the Southern Ocean be created to facilitate further investigations on the circumpolar distribution of this species.

25-Gbit/s burst-mode optical receiver using high-speed avalanche photodiode for 100-Gbit/s optical packet switching.

PubMed

Nada, Masahiro; Nakamura, Makoto; Matsuzaki, Hideaki

2014-01-13

25-Gbit/s error-free operation of an optical receiver is successfully demonstrated against burst-mode optical input signals without preambles. The receiver, with a high-sensitivity avalanche photodiode and burst-mode transimpedance amplifier, exhibits sufficient receiver sensitivity and an extremely quick response suitable for burst-mode operation in 100-Gbit/s optical packet switching.

Concentrating Solar Power Projects - Kimberlina Solar Thermal Power Plant |

Science.gov Websites

MW Gross: 5.0 MW Status: Currently Non-Operational Start Year: 2008 Do you have more information , corrections, or comments? Background Technology: Linear Fresnel reflector Status: Currently Non-Operational Manufacturer: Ausra Receiver Manufacturer : Ausra Receiver Type: Non-evacuated Receiver Length: 385 m Heat

How do risk preferences relate to malaria care-seeking behavior and the acceptability of a new health technology in Nigeria?

PubMed

Liu, Jenny; Modrek, Sepideh; Anyanti, Jennifer; Nwokolo, Ernest; De La Cruz, Anna; Schatzkin, Eric; Isiguzo, Chinwoke; Ujuju, Chinazo; Montagu, Dominic

2014-09-05

To reduce the burden of disease from malaria, innovative approaches are needed to engender behavior change. One unobservable, but fundamental trait-preferences for risk-may influence individuals' willingness to adopt new health technologies. We explore the association of risk preferences with malaria care-seeking behavior and the acceptability of malaria rapid diagnostic tests (RDTs) to inform RDT scale-up plans. In Oyo State, Nigeria, adult customers purchasing anti-malarial medications at selected drug shops took surveys and received an RDT as they exited. After an initial risk preference assessment via a simple lottery game choice, individuals were given their RDT result and treatment advice, and called four days later to assess treatment adherence. We used bivariable and multivariable regression analysis to assess the association of risk game choices with malaria care-seeking behaviors and RDT acceptability. Of 448 respondents, 63.2% chose the lottery game with zero variance in expected payout, 27.9% chose the game with low variance, and 8.9% chose the game with high variance. Compared to participants who chose lower variance games, individuals choosing higher variance games were older, less educated, more likely to be male, and were more likely to patronize lower quality drug shops, seek care immediately, and report complete disability due to their illness. In contrast, individuals choosing lower variance games were more likely to follow the correct treatment directions and were more likely to report an increase in their willingness to pay for an RDT compared to other risk groups, our two measures of RDT acceptability. Differences in estimated associations between risk game choices and selected care-seeking behaviors remained after controlling sociodemographic confounders. The uptake of health diagnostic information in terms of translating the RDT experience into willingness to pay for an RDT and treatment adherence to test results may vary according to risk preferences. Hence, health promotion communications may want to be crafted bearing in mind differences in uptake among people of different risk preferences to encourage wider RDT adoption and more rational malaria treatment. Estimates will serve as the basis for power calculations for an expanded study.

Superconductive hot-electron-bolometer mixer receiver for 800-GHz operation

NASA Astrophysics Data System (ADS)

Kawamura, J.; Blundell, R.; Tong, C.-Y. E.; Papa, D. C.; Hunter, T. R.; Paine, S. N.; Patt, F.; Gol'Tsman, G.; Cherednichenko, S.; Voronov, B.; Gershenzon, E.

2000-04-01

In this paper, we describe a superconductive hot-electron-bolometer mixer receiver designed to operate in the partially transmissive 350-μm atmospheric window. The receiver employs an NbN thin-film microbridge as the mixer element, in which the main cooling mechanism of the hot electrons is through electron-phonon interaction. At a local-oscillator frequency of 808 GHz, the measured double-sideband receiver noise temperature is Trx=970 K, across a 1-GHz intermediate-frequency bandwidth centered at 1.8 GHz. We have measured the linearity of the receiver and the amount of local-oscillator power incident on the mixer for optimal operation, which is PLO ≈ 1 microwatt. This receiver was used in making observations as a facility instrument at the Heinrich Hertz Telescope, Mt. Graham, AZ, during the 1998-1999 winter observing season.

Postoperative Outcomes in Vedolizumab-Treated Patients Undergoing Abdominal Operations for Inflammatory Bowel Disease.

PubMed

Lightner, Amy L; Raffals, Laura E; Mathis, Kellie L; Cima, Robert R; Tse, Chung Sang; Pemberton, John H; Dozois, Eric J; Loftus, Edward V

2017-02-01

Vedolizumab was recently approved by the Food and Drug Administration for the treatment of moderate to severe ulcerative colitis [UC] and Crohn's disease [CD]. No study to date has examined the rate of postoperative infectious complications among patients who received vedolizumab in the perioperative period. We sought to determine the 30-day postoperative infectious complication rate among inflammatory bowel disease [IBD] patients who received vedolizumab within 12 weeks of an abdominal operation as compared to patients who received tumour necrosis factor α [TNFα] inhibitors or no biological therapy. A retrospective chart review between May 1, 2014 and December 31, 2015 of adult IBD patients who underwent an abdominal operation was performed. The study cohort comprised patients who received vedolizumab within 12 weeks of their abdominal operation and the control cohorts were patients who received TNFα inhibitors or no biological therapy. In total, 94 patients received vedolizumab within 12 weeks of an abdominal operation. Fifty experienced postoperative complications [53%], 35 of which were surgical site infections [SSIs] [36%]. The vedolizumab group experienced significantly higher rates of any postoperative infection [53% vs 33% anti-TNF and 28% non-biologics; p<0.001] and SSI [37% vs 10% and 13%; p<0.001]. On univariate and multivariate analysis, exposure to vedolizumab remained a significant predictor of postoperative SSI [p<0.001]. Thirty-seven per cent of IBD patients who received vedolizumab within 30 days of a major abdominal operation experienced a 30-day postoperative SSI, significantly higher than patients receiving TNFα inhibitors or no biological therapy. Vedolizumab within 12 weeks of surgery remained the only predictor of 30-day postoperative SSI on multivariate analysis. Copyright © 2016 European Crohn’s and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Variability in hand-arm vibration during grinding operations.

PubMed

Liljelind, Ingrid; Wahlström, Jens; Nilsson, Leif; Toomingas, Allan; Burström, Lage

2011-04-01

Measurements of exposure to vibrations from hand-held tools are often conducted on a single occasion. However, repeated measurements may be crucial for estimating the actual dose with good precision. In addition, knowledge of determinants of exposure could be used to improve working conditions. The aim of this study was to assess hand-arm vibration (HAV) exposure during different grinding operations, in order to obtain estimates of the variance components and to evaluate the effect of work postures. Ten experienced operators used two compressed air-driven angle grinders of the same make in a simulated work task at a workplace. One part of the study consisted of using a grinder while assuming two different working postures: at a standard work bench (low) and on a wall with arms elevated and the work area adjusted to each operator's height (high). The workers repeated the task three times. In another part of the study, investigating the wheel wear, for each grinder, the operators used two new grinding wheels and with each wheel the operator performed two consecutive 1-min grinding tasks. Both grinding tasks were conducted on weld puddles of mild steel on a piece of mild steel. Measurements were taken according to ISO-standard 5349 [the equivalent hand-arm-weighted acceleration (m s(-2)) averaged over 1 min]. Mixed- and random-effects models were used to investigate the influence of the fixed variables and to estimate variance components. The equivalent hand-arm-weighted acceleration assessed when the task was performed on the bench and at the wall was 3.2 and 3.3 m s(-2), respectively. In the mixed-effects model, work posture was not a significant variable. The variables 'operator' and 'grinder' together explained only 12% of the exposure variability and 'grinding wheel' explained 47%; the residual variability of 41% remained unexplained. When the effect of grinding wheel wear was investigated in the random-effects model, 37% of the variability was associated with the wheel while minimal variability was associated with the operator or the grinder and 37% was unexplained. The interaction effect of grinder and operator explained 18% of the variability. In the wheel wear test, the equivalent hand-arm-weighted accelerations for Grinder 1 during the first and second grinding minutes were 3.4 and 2.9 m s(-2), respectively, and for Grinder 2, they were 3.1 and 2.9 m s(-2), respectively. For Grinder 1, the equivalent hand-arm-weighted acceleration during the first grinding minute was significantly higher (P = 0.04) than during the second minute. Work posture during grinding operations does not appear to affect the level of HAV. Grinding wheels explained much of the variability in this study, but almost 40% of the variance remained unexplained. The considerable variability in the equivalent hand-arm-weighted acceleration has an impact on the risk assessment at both the group and the individual level.

Effects of intraosseous epinephrine in a cardiac arrest swine model.

PubMed

Wong, Marc R; Reggio, Matt J; Morocho, Freddy R; Holloway, Monica M; Garcia-Blanco, Jose C; Jenkins, Constance; Johnson, Arthur D

2016-04-01

Interruptions in cardiopulmonary resuscitation (CPR) to obtain vascular access reduces blood flow to vital organs. Tibial intraosseous (TIO) access may be a faster alternative to intravenous (IV) access for delivery of vasoactive medications. The purpose of this study was to examine the differences in pharmacokinetics and pharmacodynamics of TIO- and IV-delivered epinephrine. A prospective, between subjects, experimental design comparing Cmax, Tmax, return of spontaneous circulation (ROSC), and time to ROSC. Adult male swine were divided into three equal groups (n = 7) all received CPR and defibrillation: the second group received IV epinephrine and the third group received tibial intraosseous epinephrine. Swine were placed in cardiac arrest for 2 min before CPR was initiated. After 2 min of CPR, epinephrine was delivered by IV or TIO, and serial blood samples were collected over 4 min. There were no significant differences between IV versus TIO epinephrine in achieving ROSC, time to ROSC, and Cmax. A one-way analysis of variance demonstrated a significant difference between the IV and TIO groups in Tmax (P = 0.025). A Fisher exact test demonstrated a significant difference between IV epinephrine versus CPR/Defib only (P = 0.035) and TIO epinephrine versus CPR/Defib only (P = 0.010) in achieving ROSC. A multivariate analysis of variance showed significant differences in IV versus intraosseous epinephrine concentration at specific time intervals: 60 (P = 0.023), 90 (P = 0.001), and 120 (P < 0.000) sec. In the context of ROSC, epinephrine delivered via TIO route is a clinically relevant alternative to IV administration. When IV access cannot be immediately obtained in cardiac arrest patients, TIO access should be considered. Published by Elsevier Inc.

Generation of a Parabolic Trough Collector Efficiency Curve from Separate Measurements of Outdoor Optical Efficiency and Indoor Receiver Heat Loss: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kutscher, C.; Burkholder, F.; Stynes, K.

2010-10-01

The overall efficiency of a parabolic trough collector is a function of both the fraction of direct normal radiation absorbed by the receiver (the optical efficiency) and the heat lost to the environment when the receiver is at operating temperature. The overall efficiency can be determined by testing the collector under actual operating conditions or by separately measuring these two components. This paper describes how outdoor measurement of the optical efficiency is combined with laboratory measurements of receiver heat loss to obtain an overall efficiency curve. Further, it presents a new way to plot efficiency that is more robust overmore » a range of receiver operating temperatures.« less

Stable “Trait” Variance of Temperament as a Predictor of the Temporal Course of Depression and Social Phobia

PubMed Central

Naragon-Gainey, Kristin; Gallagher, Matthew W.; Brown, Timothy A.

2013-01-01

A large body of research has found robust associations between dimensions of temperament (e.g., neuroticism, extraversion) and the mood and anxiety disorders. However, mood-state distortion (i.e., the tendency for current mood state to bias ratings of temperament) likely confounds these associations, rendering their interpretation and validity unclear. This issue is of particular relevance to clinical populations who experience elevated levels of general distress. The current study used the “trait-state-occasion” latent variable model (Cole, Martin, & Steiger, 2005) to separate the stable components of temperament from transient, situational influences such as current mood state. We examined the predictive power of the time-invariant components of temperament on the course of depression and social phobia in a large, treatment-seeking sample with mood and/or anxiety disorders (N = 826). Participants were assessed three times over the course of one year, using interview and self-report measures; most participants received treatment during this time. Results indicated that both neuroticism/behavioral inhibition (N/BI) and behavioral activation/positive affect (BA/P) consisted largely of stable, time-invariant variance (57% to 78% of total variance). Furthermore, the time-invariant components of N/BI and BA/P were uniquely and incrementally predictive of change in depression and social phobia, adjusting for initial symptom levels. These results suggest that the removal of state variance bolsters the effect of temperament on psychopathology among clinically distressed individuals. Implications for temperament-psychopathology models, psychopathology assessment, and the stability of traits are discussed. PMID:24016004

An evaluation of soil sampling for 137Cs using various field-sampling volumes.

PubMed

Nyhan, J W; White, G C; Schofield, T G; Trujillo, G

1983-05-01

The sediments from a liquid effluent receiving area at the Los Alamos National Laboratory and soils from an intensive study area in the fallout pathway of Trinity were sampled for 137Cs using 25-, 500-, 2500- and 12,500-cm3 field sampling volumes. A highly replicated sampling program was used to determine mean concentrations and inventories of 137Cs at each site, as well as estimates of spatial, aliquoting, and counting variance components of the radionuclide data. The sampling methods were also analyzed as a function of soil size fractions collected in each field sampling volume and of the total cost of the program for a given variation in the radionuclide survey results. Coefficients of variation (CV) of 137Cs inventory estimates ranged from 0.063 to 0.14 for Mortandad Canyon sediments, whereas CV values for Trinity soils were observed from 0.38 to 0.57. Spatial variance components of 137Cs concentration data were usually found to be larger than either the aliquoting or counting variance estimates and were inversely related to field sampling volume at the Trinity intensive site. Subsequent optimization studies of the sampling schemes demonstrated that each aliquot should be counted once, and that only 2-4 aliquots out of as many as 30 collected need be assayed for 137Cs. The optimization studies showed that as sample costs increased to 45 man-hours of labor per sample, the variance of the mean 137Cs concentration decreased dramatically, but decreased very little with additional labor.

Stable "trait" variance of temperament as a predictor of the temporal course of depression and social phobia.

PubMed

Naragon-Gainey, Kristin; Gallagher, Matthew W; Brown, Timothy A

2013-08-01

A large body of research has found robust associations between dimensions of temperament (e.g., neuroticism, extraversion) and the mood and anxiety disorders. However, mood-state distortion (i.e., the tendency for current mood state to bias ratings of temperament) likely confounds these associations, rendering their interpretation and validity unclear. This issue is of particular relevance to clinical populations who experience elevated levels of general distress. The current study used the "trait-state-occasion" latent variable model (D. A. Cole, N. C. Martin, & J. H. Steiger, 2005) to separate the stable components of temperament from transient, situational influences such as current mood state. We examined the predictive power of the time-invariant components of temperament on the course of depression and social phobia in a large, treatment-seeking sample with mood and/or anxiety disorders (N = 826). Participants were assessed 3 times over the course of 1 year, using interview and self-report measures; most participants received treatment during this time. Results indicated that both neuroticism/behavioral inhibition (N/BI) and behavioral activation/positive affect (BA/P) consisted largely of stable, time-invariant variance (57% to 78% of total variance). Furthermore, the time-invariant components of N/BI and BA/P were uniquely and incrementally predictive of change in depression and social phobia, adjusting for initial symptom levels. These results suggest that the removal of state variance bolsters the effect of temperament on psychopathology among clinically distressed individuals. Implications for temperament-psychopathology models, psychopathology assessment, and the stability of traits are discussed. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Benchmarking surgeon satisfaction at academic health centers: a nationwide comparative survey.

PubMed

Drachman, D A

1996-01-01

Forty-six academic health centers (AHCs) belonging to the University HealthSystem consortium joined forces to compare the efficiency of their surgical services and to identify best practices. In addition to measures of operational performance, surgeon satisfaction with the surgical services provided was measured by using a standardized questionnaire. From hospital records, indicators of the efficiency of surgical services were collected in three main areas: scheduling, preoperative testing and assessment, and the intraoperative process. Responding to a mail questionnaire, a sample of surgeons rated their satisfaction with key aspects of surgical services including scheduling, operating room staff, and equipment/supplies. On the basis of a review of the operational measures and the survey results, high performers were identified. Site visits were made to several of these high performers to uncover the critical factors responsible for their success. The survey revealed distinct variations in surgeon satisfaction across the participating institutions. Numerical benchmarks were obtained for surgeon satisfaction with each key component of surgical services. Scheduling was the most important component of overall surgeon satisfaction, explaining 71% of the variance in the rating of overall satisfaction with surgical services. High operational efficiency and high surgeon satisfaction were not incompatible. Several of the participating institutions were able to achieve both. These results were disseminated to all of the participants at a national meeting as well as in written form. The surgeon satisfaction survey allowed the participants to establish benchmarks for surgeon satisfaction for each key component of the surgical services they receive. The site visits revealed several common characteristics of highly efficient surgical services. Taken by themselves, the participating institutions might have been reluctant to consider adopting these best practices for fear of alienating the surgical staff. The availability of data on surgeon satisfaction showed the participants that these best practices can coexist with high levels of surgeon satisfaction. This has helped to promote their adoption by the other participating institutions.

12 CFR 233.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... regulation (such as “originating depository financial institution,” “operator,” “originating gateway operator,” “receiving depository financial institution,” “receiving gateway operator,” and “third-party sender”) are... users to a computer server, including specifically a service or system that provides access to the...

31 CFR 132.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... regulation (such as “originating depository financial institution,” “operator,” “originating gateway operator,” “receiving depository financial institution,” “receiving gateway operator,” and “third-party sender”) are... users to a computer server, including specifically a service or system that provides access to the...

DPLL implementation in carrier acquisition and tracking for burst DS-CDMA receivers.

PubMed

Guan, Yun-feng; Zhang, Zhao-yang; Lai, Li-feng

2003-01-01

This paper presents the architectures, algorithms, and implementation considerations of the digital phase locked loop (DPLL) used for burst-mode packet DS-CDMA receivers. As we know, carrier offset is a rather challenging problem in CDMA system. According to different applications, different DPLL forms should be adopted to correct different maximum carrier offset in CDMA systems. One classical DPLL and two novel DPLL forms are discussed in the paper. The acquisition range of carrier offset can be widened by using the two novel DPLL forms without any performance degradation such as longer acquisition time or larger variance of the phase error. The maximum acquisition range is 1/(4T), where T is the symbol period. The design can be implemented by FPGA directly.

Message framing and color combination in the perception of medical information.

PubMed

Chien, Yu-Hung

2011-04-01

A 2 x 2 between-subjects design was used to examine the effects of message framing (gain vs loss) and color combination (red background with white characters vs white background with black characters) on 120 university students' perception of materials promoting the H1N1 flu vaccine and their willingness to receive the vaccine after they had read the materials. Each participant completed a 6-item questionnaire, and the results of an analysis of variance showed that participants rated vaccine information presented through loss-framed messages as having greater interest and leading to greater understanding. Loss-framed messages presented on a white background with black characters significantly increased the willingness of the participants to receive the vaccine.

12. VIEW OF OPERATING ROOMRCA COMMUNICATION REC STATION (THIS ROOM ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. VIEW OF OPERATING ROOM-RCA COMMUNICATION REC STATION (THIS ROOM WAS ORIGINALLY A MOTOR GENERATOR FACILITY AND SUPPLIED DC POWER TO AN EARLIER GENERATION OF POINT-TO-POINT RECEIVERS ON SECOND FLOOR). VIEW SHOWS TRANSMITTER CONTROL STATION AND AUDIO CONTROL STATION (LEFT, WATKINS-JOHNSON WJ-8718-23. HP RECEIVERS AND KENWOOD R-5000 COMMUNICATIONS RECEIVERS (220 DEGREES). - Marconi Radio Sites, Receiving, Point Reyes Station, Marin County, CA

Effect of non-normality on test statistics for one-way independent groups designs.

PubMed

Cribbie, Robert A; Fiksenbaum, Lisa; Keselman, H J; Wilcox, Rand R

2012-02-01

The data obtained from one-way independent groups designs is typically non-normal in form and rarely equally variable across treatment populations (i.e., population variances are heterogeneous). Consequently, the classical test statistic that is used to assess statistical significance (i.e., the analysis of variance F test) typically provides invalid results (e.g., too many Type I errors, reduced power). For this reason, there has been considerable interest in finding a test statistic that is appropriate under conditions of non-normality and variance heterogeneity. Previously recommended procedures for analysing such data include the James test, the Welch test applied either to the usual least squares estimators of central tendency and variability, or the Welch test with robust estimators (i.e., trimmed means and Winsorized variances). A new statistic proposed by Krishnamoorthy, Lu, and Mathew, intended to deal with heterogeneous variances, though not non-normality, uses a parametric bootstrap procedure. In their investigation of the parametric bootstrap test, the authors examined its operating characteristics under limited conditions and did not compare it to the Welch test based on robust estimators. Thus, we investigated how the parametric bootstrap procedure and a modified parametric bootstrap procedure based on trimmed means perform relative to previously recommended procedures when data are non-normal and heterogeneous. The results indicated that the tests based on trimmed means offer the best Type I error control and power when variances are unequal and at least some of the distribution shapes are non-normal. © 2011 The British Psychological Society.

A Robust Crowdsourcing-Based Indoor Localization System.

PubMed

Zhou, Baoding; Li, Qingquan; Mao, Qingzhou; Tu, Wei

2017-04-14

WiFi fingerprinting-based indoor localization has been widely used due to its simplicity and can be implemented on the smartphones. The major drawback of WiFi fingerprinting is that the radio map construction is very labor-intensive and time-consuming. Another drawback of WiFi fingerprinting is the Received Signal Strength (RSS) variance problem, caused by environmental changes and device diversity. RSS variance severely degrades the localization accuracy. In this paper, we propose a robust crowdsourcing-based indoor localization system (RCILS). RCILS can automatically construct the radio map using crowdsourcing data collected by smartphones. RCILS abstracts the indoor map as the semantics graph in which the edges are the possible user paths and the vertexes are the location where users may take special activities. RCILS extracts the activity sequence contained in the trajectories by activity detection and pedestrian dead-reckoning. Based on the semantics graph and activity sequence, crowdsourcing trajectories can be located and a radio map is constructed based on the localization results. For the RSS variance problem, RCILS uses the trajectory fingerprint model for indoor localization. During online localization, RCILS obtains an RSS sequence and realizes localization by matching the RSS sequence with the radio map. To evaluate RCILS, we apply RCILS in an office building. Experiment results demonstrate the efficiency and robustness of RCILS.

A Robust Crowdsourcing-Based Indoor Localization System

PubMed Central

Zhou, Baoding; Li, Qingquan; Mao, Qingzhou; Tu, Wei

2017-01-01

WiFi fingerprinting-based indoor localization has been widely used due to its simplicity and can be implemented on the smartphones. The major drawback of WiFi fingerprinting is that the radio map construction is very labor-intensive and time-consuming. Another drawback of WiFi fingerprinting is the Received Signal Strength (RSS) variance problem, caused by environmental changes and device diversity. RSS variance severely degrades the localization accuracy. In this paper, we propose a robust crowdsourcing-based indoor localization system (RCILS). RCILS can automatically construct the radio map using crowdsourcing data collected by smartphones. RCILS abstracts the indoor map as the semantics graph in which the edges are the possible user paths and the vertexes are the location where users may take special activities. RCILS extracts the activity sequence contained in the trajectories by activity detection and pedestrian dead-reckoning. Based on the semantics graph and activity sequence, crowdsourcing trajectories can be located and a radio map is constructed based on the localization results. For the RSS variance problem, RCILS uses the trajectory fingerprint model for indoor localization. During online localization, RCILS obtains an RSS sequence and realizes localization by matching the RSS sequence with the radio map. To evaluate RCILS, we apply RCILS in an office building. Experiment results demonstrate the efficiency and robustness of RCILS. PMID:28420108

Sodium reflux pool-boiler solar receiver on-sun test results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andraka, C E; Moreno, J B; Diver, R B

1992-06-01

The efficient operation of a Stirling engine requires the application of a high heat flux to the relatively small area occupied by the heater head tubes. Previous attempts to couple solar energy to Stirling engines generally involved directly illuminating the heater head tubes with concentrated sunlight. In this study, operation of a 75-kW{sub t} sodium reflux pool-boiler solar receiver has been demonstrated and its performance characterized on Sandia's nominal 75-kW{sub t} parabolic-dish concentrator, using a cold-water gas-gap calorimeter to simulate Stirling engine operation. The pool boiler (and more generally liquid-metal reflux receivers) supplies heat to the engine in the formmore » of latent heat released from condensation of the metal vapor on the heater head tubes. The advantages of the pool boiler include uniform tube temperature, leading to longer life and higher temperature available to the engine, and decoupling of the design of the solar absorber from the engine heater head. The two-phase system allows high input thermal flux, reducing the receiver size and losses, therefore improving system efficiency. The receiver thermal efficiency was about 90% when operated at full power and 800{degree}C. Stable sodium boiling was promoted by the addition of 35 equally spaced artificial cavities in the wetted absorber surface. High incipient boiling superheats following cloud transients were suppressed passively by the addition of small amounts of xenon gas to the receiver volume. Stable boiling without excessive incipient boiling superheats was observed under all operating conditions. The receiver developed a leak during performance evaluation, terminating the testing after accumulating about 50 hours on sun. The receiver design is reported here along with test results including transient operations, steady-state performance evaluation, operation at various temperatures, infrared thermography, x-ray studies of the boiling behavior, and a postmortem analysis.« less

Health literacy, self-efficacy, and self-care behaviors in patients with type 2 diabetes mellitus.

PubMed

Bohanny, Walton; Wu, Shu-Fang Vivienne; Liu, Chieh-Yu; Yeh, Shu-Hui; Tsay, Shiow-Luan; Wang, Tsae-Jyy

2013-09-01

The study purpose was to explore the relationships among health literacy, self-efficacy, and self-care behaviors of patients with type 2 diabetes. A cross-sectional study with a descriptive correlational design was conducted. Patients (N = 150) with type 2 diabetes were recruited from diabetes clinics in the Marshall Islands. Levels of health literacy, self-efficacy, and self-care behaviors were assessed by a questionnaire. Health literacy, receiving diabetes education, and employment status together explained 11.8% of the variance in self-efficacy (F((3,147)) = 7.58, p < .001). Patients who had higher health literacy, received more diabetes-related education, were currently employed and had better self-efficacy. Self-efficacy and marital status together explained 16.7% of the variance in self-care behaviors (F((2,148)) = 15.96, p < .001). Patients who had higher self-efficacy and who were married had better self-care behaviors. Strategies are needed to incorporate the concept of self-efficacy in the design of diabetes education to promote patients' self-care behaviors, with an emphasis on dealing with hyper- or hypoglycemia, following the diet plan, and checking blood sugar levels as recommended. Diabetes education material that requires a lower literacy level may be needed for older or unemployed adult populations. ©2013 The Author(s) ©2013 American Association of Nurse Practitioners.

A New Variable Weighting and Selection Procedure for K-Means Cluster Analysis

ERIC Educational Resources Information Center

Steinley, Douglas; Brusco, Michael J.

2008-01-01

A variance-to-range ratio variable weighting procedure is proposed. We show how this weighting method is theoretically grounded in the inherent variability found in data exhibiting cluster structure. In addition, a variable selection procedure is proposed to operate in conjunction with the variable weighting technique. The performances of these…

A VLBI variance-covariance analysis interactive computer program. M.S. Thesis

NASA Technical Reports Server (NTRS)

Bock, Y.

1980-01-01

An interactive computer program (in FORTRAN) for the variance covariance analysis of VLBI experiments is presented for use in experiment planning, simulation studies and optimal design problems. The interactive mode is especially suited to these types of analyses providing ease of operation as well as savings in time and cost. The geodetic parameters include baseline vector parameters and variations in polar motion and Earth rotation. A discussion of the theroy on which the program is based provides an overview of the VLBI process emphasizing the areas of interest to geodesy. Special emphasis is placed on the problem of determining correlations between simultaneous observations from a network of stations. A model suitable for covariance analyses is presented. Suggestions towards developing optimal observation schedules are included.

Reducing cost with autonomous operations of the Deep Space Network radio science receiver

NASA Technical Reports Server (NTRS)

Asmar, S.; Anabtawi, A.; Connally, M.; Jongeling, A.

2003-01-01

This paper describes the Radio Science Receiver system and the savings it has brought to mission operations. The design and implementation of remote and autonomous operations will be discussed along with the process of including user feedback along the way and lessons learned and procedures avoided.

The development of an advanced generic solar dynamic heat receiver thermal model

NASA Technical Reports Server (NTRS)

Wu, Y. C.; Roschke, E. J.; Kohout, L.

1988-01-01

An advanced generic solar dynamic heat receiver thermal model under development which can analyze both orbital transient and orbital average conditions is discussed. This model can be used to study advanced receiver concepts, evaluate receiver concepts under development, analyze receiver thermal characteristics under various operational conditions, and evaluate solar dynamic system thermal performances in various orbit conditions. The model and the basic considerations that led to its creation are described, and results based on a set of baseline orbit, configuration, and operational conditions are presented to demonstrate the working of the receiver model.

Measuring social impacts of breast carcinoma treatment in Chinese women.

PubMed

Fielding, Richard; Lam, Wendy W T

2004-06-15

There is no existing instrument that is suitable for measuring the social impact of breast carcinoma (BC) and its treatment among women of Southern Chinese descent. In the current study, the authors assessed the validity of the Chinese Social Adjustment Scale, which was designed to address the need for such an instrument. Five dimensions of social concern were identified in a previous study of Cantonese-speaking Chinese women with BC; these dimensions were family and other relationships, intimacy, private self-image, and public self-image. The authors designed 40 items to address perceptions of change in these areas. These items were administered to a group of 226 women who had received treatment for BC, and factor analysis subsequently was performed to determine construct characteristics. The resulting draft instrument then was administered, along with other measures for the assessment of basic psychometric properties, to a second group of 367 women who recently had undergone surgery for BC. Factor analysis optimally identified 5 factors (corresponding to 33 items): 1) Relationships with Family (10 items, accounting for 22% of variance); 2) Self-Image (7 items, accounting for 15% of variance); 3) Relationships with Friends (7 items, accounting for 8% of variance); 4) Social Enjoyment (4 items, accounting for 6% of variance); and 5) Attractiveness and Sexuality (5 items, accounting for 5% of variance). Subscales were reliable (alpha = 0.63-0.93) and exhibited convergent validity in positive correlations with related measures and divergent validity in appropriate inverse or nonsignificant correlations with other measures. Criterion validity was good, and sensitivity was acceptable. Patterns of change on the scales were consistent with reports in the literature. Self-administration resulted in improved sensitivity. The 33-item Chinese Social Adjustment Scale validly, reliably, and sensitively measures the social impact of BC on Cantonese-speaking Hong Kong Chinese women. Further development of the scale to increase its sensitivity is underway. Copyright 2004 American Cancer Society.

Does Receiving a Blood Transfusion Predict for Length of Stay in Children Undergoing Cranial Vault Remodeling for Craniosynostosis? Outcomes Using the Pediatric National Surgical Quality Improvement Program Dataset.

PubMed

Markiewicz, Michael R; Alden, Tord; Momin, Mohmed Vasim; Olsson, Alexis B; Jurado, Ray J; Abdullah, Fizan; Miloro, Michael

2017-08-01

Recent interventions have aimed at reducing the need for blood transfusions in the perioperative period in patients with craniosynostosis undergoing cranial vault remodeling. However, little is known regarding whether the receipt of a blood transfusion influences the length of hospital stay. The purpose of this study was to assess whether the receipt of a blood transfusion in patients undergoing cranial vault remodeling is associated with an increased length of stay. To address the research purposes, we designed a retrospective cohort study using the 2014 Pediatric National Surgical Quality Improvement Program (NSQIP Peds) dataset. The primary predictor variable was whether patients received a blood transfusion during cranial vault remodeling. The primary outcome variable was length of hospital stay after the operation. The association between the receipt of blood transfusions and length of stay was assessed using the Student t test. The association between other covariates and the outcome variable was assessed using linear regression, analysis of variance, and the Tukey test for post hoc pair-wise comparisons. The sample was composed of 756 patients who underwent cranial vault remodeling: 503 who received blood transfusions and 253 who did not. The primary predictor variable of blood transfusion was associated with an increased length of stay (4.1 days vs 3.0 days, P = .03). Other covariates associated with an increased length of stay included race, American Society of Anesthesiologists status, premature birth, presence of a congenital malformation, and number of sutures involved in craniosynostosis. The receipt of a blood transfusion in the perioperative period in patients with craniosynostosis undergoing cranial vault remodeling was associated with an increased length of stay. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Probiotics improve insulin resistance status in an experimental model of Alzheimer's disease.

PubMed

Athari Nik Azm, Somayeh; Djazayeri, Abolghassem; Safa, Majid; Azami, Kian; Djalali, Mahmoud; Sharifzadeh, Mohammad; Vafa, Mohammadreza

2017-01-01

Background: Nowadays, Alzheimer's disease (AD) is considered as Type 3 diabetes in which insulin resistance is the common cause of both diseases. Disruption of insulin signaling cascade and insulin resistance can induce AD; and central insulin resistance causes systemic alterations in serum insulin, FBS levels, and lipid profile. Studies have shown that probiotics ( Lactobacillus and Bifidobacterium species) can be used as a nutritional approach to improve these metabolic changes. We assessed the probiotic effect (4 species of Lactobacillus and Bifidobacterium ) on insulin resistance biomarkers in an experimental model of AD. Methods: A total of 60 rats were divided into 5 groups: (1) a control group without surgical and dietary intervention; (2) a controlprobiotics group receiving probiotics for 8 weeks, but not receiving any surgical intervention; (3) a group receiving a sham operation in which PBS was injected intrahippocampus but without dietary intervention; (4) an Alzheimer group for which Amyloid-ß (Aß) 1- 42 was injected intrahippocampus but without dietary intervention; (5) and an Alzheimer-probiotics group for which Aß1-42 was injected intrahippocampus and given 2g probiotics for 8 weeks. The FBS levels and lipid profile were measured by a calorimetric method, insulin levels were detected by an ELISA kit, and HOMA-IR was calculated using a formula. ANOVA (one way analysis of variance followed by Bonferroni comparisons post hoc) was used to compare all the variables between groups. Results: Serum glucose, insulin levels, and HOMA-IR index increased in the Alzheimer group compared to the control (p<0.001), while probiotics decreased only insulin level and HOMA-IR index in AP group compared to Alzheimer group (p<0.001). Also, TG levels increased in the Alzheimer group (p<0.001), but no significant difference was detected between Alzheimer and Alzheimerprobiotics group. Conclusion: It seems that probiotics play an effective role in controlling glycemic status of Alzheimer's disease.

25 CFR 47.3 - How does a Bureau-operated school find out how much funding it will receive?

Code of Federal Regulations, 2014 CFR

2014-04-01

... EDUCATION UNIFORM DIRECT FUNDING AND SUPPORT FOR BUREAU-OPERATED SCHOOLS § 47.3 How does a Bureau-operated school find out how much funding it will receive? The Office of Indian Education Programs (OIEP) will... 25 Indians 1 2014-04-01 2014-04-01 false How does a Bureau-operated school find out how much...

25 CFR 47.3 - How does a Bureau-operated school find out how much funding it will receive?

Code of Federal Regulations, 2011 CFR

2011-04-01

... EDUCATION UNIFORM DIRECT FUNDING AND SUPPORT FOR BUREAU-OPERATED SCHOOLS § 47.3 How does a Bureau-operated school find out how much funding it will receive? The Office of Indian Education Programs (OIEP) will... 25 Indians 1 2011-04-01 2011-04-01 false How does a Bureau-operated school find out how much...

25 CFR 47.3 - How does a Bureau-operated school find out how much funding it will receive?

Code of Federal Regulations, 2012 CFR

2012-04-01

... EDUCATION UNIFORM DIRECT FUNDING AND SUPPORT FOR BUREAU-OPERATED SCHOOLS § 47.3 How does a Bureau-operated school find out how much funding it will receive? The Office of Indian Education Programs (OIEP) will... 25 Indians 1 2012-04-01 2011-04-01 true How does a Bureau-operated school find out how much...

25 CFR 47.3 - How does a Bureau-operated school find out how much funding it will receive?

Code of Federal Regulations, 2013 CFR

2013-04-01

... EDUCATION UNIFORM DIRECT FUNDING AND SUPPORT FOR BUREAU-OPERATED SCHOOLS § 47.3 How does a Bureau-operated school find out how much funding it will receive? The Office of Indian Education Programs (OIEP) will... 25 Indians 1 2013-04-01 2013-04-01 false How does a Bureau-operated school find out how much...

25 CFR 47.3 - How does a Bureau-operated school find out how much funding it will receive?

Code of Federal Regulations, 2010 CFR

2010-04-01

... EDUCATION UNIFORM DIRECT FUNDING AND SUPPORT FOR BUREAU-OPERATED SCHOOLS § 47.3 How does a Bureau-operated school find out how much funding it will receive? The Office of Indian Education Programs (OIEP) will... 25 Indians 1 2010-04-01 2010-04-01 false How does a Bureau-operated school find out how much...

Post-operative course of coronary artery bypass surgery patients who pre-donate autologous blood.

PubMed

Jovin, Ion S; Stelzig, Georg; Strelitz, Joachim C; Taborski, Uwe; Jovin, Angelika; Heidinger, Kathrin; Klövekorn, Wolf-Peter; Müller-Berghaus, Gert

2003-12-01

Pre-operative autologous blood donation is used to reduce the need of allogeneic blood in patients undergoing coronary bypass surgery operations, but it is not clear what impact the blood donation has on the post-operative course of these patients. We studied the post-operative course of 210 patients who pre-donated autologous blood before their coronary bypass operation (donors) and of 67 patients who were eligible to pre-donate but did not (controls). The clinical variables and the technical operative parameters of the patients in the two groups were similar. There was no significant difference between the duration of assisted ventilation post-operatively (756 +/- 197 vs. 802 +/- 395 min; P=0.54) or length of stay in the intensive care unit (1.8 +/- 1.1 vs. 1.7 +/- 0.9 days; P=0.52) of the two groups. The number of autologous units of packed red cells and of fresh frozen plasma (FFP) received by the donors was significantly higher than the number of units of allogeneic packed red cells (1.5 +/- 0.9 vs. 0.3 +/- 0.9; P=0.001) and the units of homologous FFP received by the controls (2.3 +/- 0.8 vs. 0.6 +/- 1; P=0.001). We found no evidence that autologous blood donation exerted a negative influence on the post-operative course of patients undergoing coronary bypass surgery. Patients who pre-donated blood received no allogeneic blood products, but the number of autologous blood products received by donors was higher than the number of blood products received by patients who did not pre-donate.

A Simple Method for Deriving the Confidence Regions for the Penalized Cox’s Model via the Minimand Perturbation†

PubMed Central

Lin, Chen-Yen; Halabi, Susan

2017-01-01

We propose a minimand perturbation method to derive the confidence regions for the regularized estimators for the Cox’s proportional hazards model. Although the regularized estimation procedure produces a more stable point estimate, it remains challenging to provide an interval estimator or an analytic variance estimator for the associated point estimate. Based on the sandwich formula, the current variance estimator provides a simple approximation, but its finite sample performance is not entirely satisfactory. Besides, the sandwich formula can only provide variance estimates for the non-zero coefficients. In this article, we present a generic description for the perturbation method and then introduce a computation algorithm using the adaptive least absolute shrinkage and selection operator (LASSO) penalty. Through simulation studies, we demonstrate that our method can better approximate the limiting distribution of the adaptive LASSO estimator and produces more accurate inference compared with the sandwich formula. The simulation results also indicate the possibility of extending the applications to the adaptive elastic-net penalty. We further demonstrate our method using data from a phase III clinical trial in prostate cancer. PMID:29326496

A Simple Method for Deriving the Confidence Regions for the Penalized Cox's Model via the Minimand Perturbation.

PubMed

Lin, Chen-Yen; Halabi, Susan

2017-01-01

We propose a minimand perturbation method to derive the confidence regions for the regularized estimators for the Cox's proportional hazards model. Although the regularized estimation procedure produces a more stable point estimate, it remains challenging to provide an interval estimator or an analytic variance estimator for the associated point estimate. Based on the sandwich formula, the current variance estimator provides a simple approximation, but its finite sample performance is not entirely satisfactory. Besides, the sandwich formula can only provide variance estimates for the non-zero coefficients. In this article, we present a generic description for the perturbation method and then introduce a computation algorithm using the adaptive least absolute shrinkage and selection operator (LASSO) penalty. Through simulation studies, we demonstrate that our method can better approximate the limiting distribution of the adaptive LASSO estimator and produces more accurate inference compared with the sandwich formula. The simulation results also indicate the possibility of extending the applications to the adaptive elastic-net penalty. We further demonstrate our method using data from a phase III clinical trial in prostate cancer.

Investigation of the variance and spectral anisotropies of the solar wind turbulence with multiple point spacecraft observations

NASA Astrophysics Data System (ADS)

Vech, Daniel; Chen, Christopher

2016-04-01

One of the most important features of the plasma turbulence is the anisotropy, which arises due to the presence of the magnetic field. The understanding of the anisotropy is particularly important to reveal how the turbulent cascade operates. It is well known that anisotropy exists with respect to the mean magnetic field, however recent theoretical studies suggested anisotropy with respect to the radial direction. The purpose of this study is to investigate the variance and spectral anisotropies of the solar wind turbulence with multiple point spacecraft observations. The study includes the Advanced Composition Analyzer (ACE), WIND and Cluster spacecraft data. The second order structure functions are derived for two different spacecraft configurations: when the pair of spacecraft are separated radially (with respect to the spacecraft -Sun line) and when they are separated along the transverse direction. We analyze the effect of the different sampling directions on the variance anisotropy, global spectral anisotropy, local 3D spectral anisotropy and discuss the implications for our understanding of solar wind turbulence.

Nonnormality increases variance of gravity waves trapped in a tilted box

NASA Astrophysics Data System (ADS)

Harlander, Uwe; Borcia, Ion Dan; Krebs, Andreas

2017-04-01

We study the prototype problem of internal gravity waves in a square domain tilted with respect to the gravity vector by an angle theta. Only when theta is zero regular normal modes exist, for all other angles wave attractors and singularities dominate the flow. We show that the linear operator of the governing PDE becomes non-normal for nonzero theta giving rise to non-modal transient growth. This growth depends on the underlying norm: for the variance norm significant growth rates can be found whereas for the energy norm, no growth is possible since there is no source for energy (in contrast to shear fows, for which the mean flow feeds the perturbations). We continue by showing that the nonnormality of the system matrix is increasing with theta and reaches a maximum when theta is 45 degree. Moreover, the growth rate is increasing as can be expected from the increasing nonnormality of the matrix. Our results imply that at least the most simple wave attractors can be seen as those initial flow fields that gain most of the variance during a given time period.

Kramers-Kronig receiver operable without digital upsampling.

PubMed

Bo, Tianwai; Kim, Hoon

2018-05-28

The Kramers-Kronig (KK) receiver is capable of retrieving the phase information of optical single-sideband (SSB) signal from the optical intensity when the optical signal satisfies the minimum phase condition. Thus, it is possible to direct-detect the optical SSB signal without suffering from the signal-signal beat interference and linear transmission impairments. However, due to the spectral broadening induced by nonlinear operations in the conventional KK algorithm, it is necessary to employ the digital upsampling at the beginning of the digital signal processing (DSP). The increased number of samples at the DSP would hinder the real-time implementation of this attractive receiver. Hence, we propose a new DSP algorithm for KK receiver operable at 2 samples per symbol. We adopt a couple of mathematical approximations to avoid the use of nonlinear operations such as logarithm and exponential functions. By using the proposed algorithm, we demonstrate the transmission of 112-Gb/s SSB orthogonal frequency-division-multiplexed signal over an 80-km fiber link. The results show that the proposed algorithm operating at 2 samples per symbol exhibits similar performance to the conventional KK one operating at 6 samples per symbol. We also present the error analysis of the proposed algorithm for KK receiver in comparison with the conventional one.

ECT treatment outcomes following performance improvement changes.

PubMed

Pulia, Kathy; Vaidya, Punit; Jayaram, Geetha; Hayat, Matthew J; Reti, Irving M

2013-11-01

Differences in electroconvulsive therapy (ECT) outcomes were explored following changes in ECT administration at our institution. Two changes were introduced: (a) switching the anesthetic agent from propofol to methohexital, and (b) using a more aggressive ECT charge dosing regimen for right unilateral (RUL) electrode placement. Length of stay (LOS) and number of treatments administered per patient were monitored. A retrospective analysis was performed of two inpatient groups treated on our Mood Disorders Unit: those who underwent ECT in the 12 months prior to the changes (n = 40) and those who underwent treatment in the 12 months after the changes (n = 38). Compared with patients receiving ECT with RUL placement prior to the changes, patients who received RUL ECT after the changes had a significantly shorter inpatient LOS (27.4 versus 18 days, p = 0.028). Treatment efficacy monitored by the Montgomery Asberg Depression Rating Scale was not impacted. The change in anesthetic agent and charge dosing each accounted for 11% of the variance in LOS among patients receiving RUL ECT. The implemented changes in ECT administration positively impacted outcome for patients receiving treatment with RUL electrode placement. Copyright 2013, SLACK Incorporated.

Processor architectures utilizing magnetic bubble and semi-conductor memories. [for the Omega navigation system

NASA Technical Reports Server (NTRS)

Parrish, E. A., Jr.; Aylor, J. H.

1975-01-01

To aid work being conducted on the feasibility of a low cost Omega navigational receiver, a control panel was designed and constructed according to supplied specifications. Since the proposed Omega receiver is designed around a microprocessor, software engineering necessary for control panel operation is included in the design. The control panel is to be used as an operational model for use in the design of a prototype receiver. A detailed description of the hardware design is presented along with a description of the software needed to operate the panel. A complete description of the operating procedures for the panel are also included.

Operational adaptability evaluation index system of pumped storage in UHV receiving-end grids

NASA Astrophysics Data System (ADS)

Yuan, Bo; Zong, Jin; Feng, Junshu

2017-01-01

Pumped storage is an effective solution to deal with the emergency reserve shortage, renewable energy accommodating and peak-shaving problems in ultra-high voltage (UHV) transmission receiving-end grids. However, governments and public opinion in China tend to evaluate the operational effectiveness of pumped storage using annual utilization hour, which may result in unreasonable and unnecessary dispatch of pumped storage. This paper built an operational adaptability evaluation index system for pumped storage in UHV-receiving end grids from three aspects: security insurance, peak-shaving and renewable energy accommodating, which can provide a comprehensive and objective way to evaluate the operational performance of a pumped storage station.

47 CFR 15.121 - Scanning receivers and frequency converters used with scanning receivers.

Code of Federal Regulations, 2010 CFR

2010-10-01

... incapable of operating (tuning), or readily being altered by the user to operate, within the frequency bands...). Scanning receivers capable of “readily being altered by the user” include, but are not limited to, those... by this paragraph shall be placed in a prominent location in the instruction manual or pamphlet...

Theoretical Limits on Multiuser Molecular Communication in Internet of Nano-Bio Things.

PubMed

Dinc, Ergin; Akan, Ozgur B

2017-06-01

In nano-bio networks, multiple transmitter-receiver pairs will operate in the same medium. Both inter-symbol interference and multi-user interference can cause saturation at the receiver side, and this effect may cause an outage. Thus, we propose a tractable framework to calculate the theoretical operating points for fully absorbing receiver.

24 CFR 990.190 - Other formula expenses (add-ons).

Code of Federal Regulations, 2010 CFR

2010-04-01

... operating subsidy is determined to be zero based on the formula is still eligible to receive operating... formula expenses (add-ons). In addition to calculating operating subsidy based on the PEL and UEL, a PHA's... receive an amount for PILOT in accordance with section 6(d) of the 1937 Act, based on its cooperation...

24 CFR 990.190 - Other formula expenses (add-ons).

Code of Federal Regulations, 2011 CFR

2011-04-01

... operating subsidy is determined to be zero based on the formula is still eligible to receive operating... formula expenses (add-ons). In addition to calculating operating subsidy based on the PEL and UEL, a PHA's... receive an amount for PILOT in accordance with section 6(d) of the 1937 Act, based on its cooperation...

Frame for a firearm

DOEpatents

Crandall, David L [Idaho Falls, ID; Watson, Richard W [Blackfoot, ID

2008-03-04

A firearm frame which is adapted to be disposed in operative relationship as a component part of a firearm, the firearm having disposed in operative relationships each with one or more of the others, a barrel, a receiver, and at least one firing mechanism; wherein the barrel and receiver form operative parts of a movable assembly and the at least one firing mechanism is disposed in a substantially stationary operative relationship therewith; the firearm frame including at least one elongated support structure discrete from the barrel and receiver, the elongated support structure being adapted to directly support the movable assembly in an operative movable relationship therewith; whereby at least one of the barrel and receiver is in direct contact with and movable on the elongated support structure; and, a firing mechanism support structure connected to the at least one elongated support structure, the firing mechanism support structure being adapted to have the firing mechanism connected thereto; the firearm frame also directly supporting the movable assembly and the firing mechanism in corresponding movable and stationary operative relationships each with the other.

Two dynamic regimes in the human gut microbiome

PubMed Central

Smillie, Chris S.; Alm, Eric J.

2017-01-01

The gut microbiome is a dynamic system that changes with host development, health, behavior, diet, and microbe-microbe interactions. Prior work on gut microbial time series has largely focused on autoregressive models (e.g. Lotka-Volterra). However, we show that most of the variance in microbial time series is non-autoregressive. In addition, we show how community state-clustering is flawed when it comes to characterizing within-host dynamics and that more continuous methods are required. Most organisms exhibited stable, mean-reverting behavior suggestive of fixed carrying capacities and abundant taxa were largely shared across individuals. This mean-reverting behavior allowed us to apply sparse vector autoregression (sVAR)—a multivariate method developed for econometrics—to model the autoregressive component of gut community dynamics. We find a strong phylogenetic signal in the non-autoregressive co-variance from our sVAR model residuals, which suggests niche filtering. We show how changes in diet are also non-autoregressive and that Operational Taxonomic Units strongly correlated with dietary variables have much less of an autoregressive component to their variance, which suggests that diet is a major driver of microbial dynamics. Autoregressive variance appears to be driven by multi-day recovery from frequent facultative anaerobe blooms, which may be driven by fluctuations in luminal redox. Overall, we identify two dynamic regimes within the human gut microbiota: one likely driven by external environmental fluctuations, and the other by internal processes. PMID:28222117

Inducing Tropical Cyclones to Undergo Brownian Motion

NASA Astrophysics Data System (ADS)

Hodyss, D.; McLay, J.; Moskaitis, J.; Serra, E.

2014-12-01

Stochastic parameterization has become commonplace in numerical weather prediction (NWP) models used for probabilistic prediction. Here, a specific stochastic parameterization will be related to the theory of stochastic differential equations and shown to be affected strongly by the choice of stochastic calculus. From an NWP perspective our focus will be on ameliorating a common trait of the ensemble distributions of tropical cyclone (TC) tracks (or position), namely that they generally contain a bias and an underestimate of the variance. With this trait in mind we present a stochastic track variance inflation parameterization. This parameterization makes use of a properly constructed stochastic advection term that follows a TC and induces its position to undergo Brownian motion. A central characteristic of Brownian motion is that its variance increases with time, which allows for an effective inflation of an ensemble's TC track variance. Using this stochastic parameterization we present a comparison of the behavior of TCs from the perspective of the stochastic calculi of Itô and Stratonovich within an operational NWP model. The central difference between these two perspectives as pertains to TCs is shown to be properly predicted by the stochastic calculus and the Itô correction. In the cases presented here these differences will manifest as overly intense TCs, which, depending on the strength of the forcing, could lead to problems with numerical stability and physical realism.

Two dynamic regimes in the human gut microbiome.

PubMed

Gibbons, Sean M; Kearney, Sean M; Smillie, Chris S; Alm, Eric J

2017-02-01

The gut microbiome is a dynamic system that changes with host development, health, behavior, diet, and microbe-microbe interactions. Prior work on gut microbial time series has largely focused on autoregressive models (e.g. Lotka-Volterra). However, we show that most of the variance in microbial time series is non-autoregressive. In addition, we show how community state-clustering is flawed when it comes to characterizing within-host dynamics and that more continuous methods are required. Most organisms exhibited stable, mean-reverting behavior suggestive of fixed carrying capacities and abundant taxa were largely shared across individuals. This mean-reverting behavior allowed us to apply sparse vector autoregression (sVAR)-a multivariate method developed for econometrics-to model the autoregressive component of gut community dynamics. We find a strong phylogenetic signal in the non-autoregressive co-variance from our sVAR model residuals, which suggests niche filtering. We show how changes in diet are also non-autoregressive and that Operational Taxonomic Units strongly correlated with dietary variables have much less of an autoregressive component to their variance, which suggests that diet is a major driver of microbial dynamics. Autoregressive variance appears to be driven by multi-day recovery from frequent facultative anaerobe blooms, which may be driven by fluctuations in luminal redox. Overall, we identify two dynamic regimes within the human gut microbiota: one likely driven by external environmental fluctuations, and the other by internal processes.

Improved uncertainty quantification in nondestructive assay for nonproliferation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burr, Tom; Croft, Stephen; Jarman, Ken

2016-12-01

This paper illustrates methods to improve uncertainty quantification (UQ) for non-destructive assay (NDA) measurements used in nuclear nonproliferation. First, it is shown that current bottom-up UQ applied to calibration data is not always adequate, for three main reasons: (1) Because there are errors in both the predictors and the response, calibration involves a ratio of random quantities, and calibration data sets in NDA usually consist of only a modest number of samples (3–10); therefore, asymptotic approximations involving quantities needed for UQ such as means and variances are often not sufficiently accurate; (2) Common practice overlooks that calibration implies a partitioningmore » of total error into random and systematic error, and (3) In many NDA applications, test items exhibit non-negligible departures in physical properties from calibration items, so model-based adjustments are used, but item-specific bias remains in some data. Therefore, improved bottom-up UQ using calibration data should predict the typical magnitude of item-specific bias, and the suggestion is to do so by including sources of item-specific bias in synthetic calibration data that is generated using a combination of modeling and real calibration data. Second, for measurements of the same nuclear material item by both the facility operator and international inspectors, current empirical (top-down) UQ is described for estimating operator and inspector systematic and random error variance components. A Bayesian alternative is introduced that easily accommodates constraints on variance components, and is more robust than current top-down methods to the underlying measurement error distributions.« less

Flight and ground tests of a GOES satellite time receiver for satellite communications applications

NASA Technical Reports Server (NTRS)

Swanson, R. L.; Nichols, S. A.

1981-01-01

A satellite time receiver was tested in various environmental conditions during the past year. The commercial receiver designed to work with the National Oceanic and Atmospheric Administration's (NOAA) Geostationary Operational Environmental Satellites (GOES). The test program included operation at low elevation during flight in a military cargo aircraft and long term comparison with laboratory standards. The GOES satellite time receiver offers an opportunity to provide easy wide area coverage synchronization at low cost.

Transient simulation of molten salt central receiver

NASA Astrophysics Data System (ADS)

Doupis, Dimitri; Wang, Chuan; Carcorze-Soto, Jorge; Chen, Yen-Ming; Maggi, Andrea; Losito, Matteo; Clark, Michael

2016-05-01

Alstom is developing concentrated solar power (CSP) utilizing 60/40wt% NaNO3-KNO3 molten salt as the working fluid in a tower receiver for the global renewable energy market. In the CSP power generation cycle, receivers undergo a daily cyclic operation due to the transient nature of solar energy. Development of robust and efficient start-up and shut-down procedures is critical to avoiding component failures due to mechanical fatigue resulting from thermal transients, thus maintaining the performance and availability of the CSP plant. The Molten Salt Central Receiver (MSCR) is subject to thermal transients during normal daily operation, a cycle that includes warmup, filling, operation, draining, and shutdown. This paper describes a study to leverage dynamic simulation and finite element analysis (FEA) in development of start-up, shutdown, and transient operation concepts for the MSCR. The results of the FEA also verify the robustness of the MSCR design to the thermal transients anticipated during the operation of the plant.

Synthetic aperture radar operator tactical target acquisition research

NASA Technical Reports Server (NTRS)

Hershberger, M. L.; Craig, D. W.

1978-01-01

A radar target acquisition research study was conducted to access the effects of two levels of 13 radar sensor, display, and mission parameters on operator tactical target acquisition. A saturated fractional-factorial screening design was employed to examine these parameters. Data analysis computed ETA squared values for main and second-order effects for the variables tested. Ranking of the research parameters in terms of importance to system design revealed four variables (radar coverage, radar resolution/multiple looks, display resolution, and display size) accounted for 50 percent of the target acquisition probability variance.

An Analysis of the Factors Generating the Variance Between the Budgeted and Actual Operating Results of the Naval Aviation Depot at North Island, California

DTIC Science & Technology

2008-06-01

management structure employs free- market system principles and encourages business-like processes that are mission driven. Since no operating funds are...variable (Potvin, 2007). 2. Unit Cost Goal NWCFs use the unit cost goal ( UCG ) for planning purposes. The UCG is an estimate of what a unit of product...mission 6. Will not interfere with depot performance This section opens the depot to the private market . 53 Chapter 159 – Real Property

Receiver-exciter controller design

NASA Technical Reports Server (NTRS)

Jansma, P. A.

1982-01-01

A description of the general design of both the block 3 and block 4 receiver-exciter controllers for the Deep Space Network (DSN) Mark IV-A System is presented along with the design approach. The controllers are designed to enable the receiver-exciter subsystem (RCV) to be configured, calibrated, initialized and operated from a central location via high level instructions. The RECs are designed to be operated under the control of the DMC subsystem. The instructions are in the form of standard subsystem blocks (SSBs) received via the local area network (LAN). The centralized control provided by RECs and other DSCC controllers in Mark IV-A is intended to reduce DSN operations costs from the Mark III era.

The correlation between ketamine and posttraumatic stress disorder in burned service members.

PubMed

McGhee, Laura L; Maani, Christopher V; Garza, Thomas H; Gaylord, Kathryn M; Black, Ian H

2008-02-01

Predisposing factors for posttraumatic stress disorder (PTSD) include experiencing a traumatic event, threat of injury or death, and untreated pain. Ketamine, an anesthetic, is used at low doses as part of a multimodal anesthetic regimen. However, since ketamine is associated with psychosomatic effects, there is a concern that ketamine may increase the risk of developing PTSD. This study investigated the prevalence of PTSD in Operation Iraqi Freedom/Operation Enduring Freedom (OIF/OEF) service members who were treated for burns in a military treatment center. The PTSD Checklist-Military (PCL-M) is a 17-question screening tool for PTSD used by the military. A score of 44 or higher is a positive screen for PTSD. The charts of all OIF/OEF soldiers with burns who completed the PCL-M screening tool (2002-2007) were reviewed to determine the number of surgeries received, the anesthetic regime used, including amounts given, the total body surface area burned, and injury severity score. Morphine equivalent units were calculated using standard dosage conversion factors. The prevalence of PTSD in patients receiving ketamine during their operation(s) was compared with patients not receiving ketamine. Of the 25,000 soldiers injured in OIF/OEF, United States Army Institute of Surgical Research received 603 burned casualties, of which 241 completed the PCL-M. Of those, 147 soldiers underwent at least one operation. Among 119 patients who received ketamine during surgery and 28 who did not; the prevalence of PTSD was 27% (32 of 119) versus 46% (13 of 28), respectively (p = 0.044). Contrary to expectations, patients receiving perioperative ketamine had a lower prevalence of PTSD than soldiers receiving no ketamine during their surgeries despite having larger burns, higher injury severity score, undergoing more operations, and spending more time in the ICU.

Sociocognitive predictors of the intention of healthcare workers to receive the influenza vaccine in Belgian, Dutch and German hospital settings.

PubMed

Lehmann, B A; Ruiter, R A C; van Dam, D; Wicker, S; Kok, G

2015-03-01

Influenza vaccination of healthcare workers (HCWs) is recommended to prevent the transmission of influenza to vulnerable patients. Nevertheless, vaccination coverage rates of HCWs in European countries have been low. To investigate the relative and combined strength of sociocognitive variables, from past research, theory and a qualitative study, in explaining the motivation of HCWs to receive the influenza vaccine. An anonymous, online questionnaire was distributed among HCWs in hospital settings in Belgium, Germany and the Netherlands between February and April 2013. Attitude and past vaccination uptake explained a considerable amount of variance in the intention of HCWs to receive the influenza vaccine. Moreover, low perceived social norms, omission bias, low moral norms, being older, having no patient contact, and being Belgian or Dutch (compared with German) increased the probability of having no intention to receive the influenza vaccine compared with being undecided about vaccination. High intention to receive the influenza vaccine was shown to be more likely than being undecided about vaccination when HCWs had high perceived susceptibility of contracting influenza, low naturalistic views, and lower motivation to receive the vaccine solely for self-protection. Country-specific interventions and a focus on different sociocognitive variables depending on the intention/lack of intention of HCWs to receive the influenza vaccine may be beneficial to promote vaccination uptake. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Microprocessor realizations of range rate filters

NASA Technical Reports Server (NTRS)

1979-01-01

The performance of five digital range rate filters is evaluated. A range rate filter receives an input of range data from a radar unit and produces an output of smoothed range data and its estimated derivative range rate. The filters are compared through simulation on an IBM 370. Two of the filter designs are implemented on a 6800 microprocessor-based system. Comparisons are made on the bases of noise variance reduction ratios and convergence times of the filters in response to simulated range signals.

An assessment of the performance of municipal constructed wetlands in Ireland.

PubMed

Hickey, Anthony; Arnscheidt, Joerg; Joyce, Eadaoin; O'Toole, James; Galvin, Gerry; O' Callaghan, Mark; Conroy, Ken; Killian, Darran; Shryane, Tommy; Hughes, Francis; Walsh, Katherine; Kavanagh, Emily

2018-03-15

While performance assessments of constructed wetlands sites around the world have appraised their capacity for effective removal of organics, a large variance remains in these sites' reported ability to retain nutrients, which appears to depend on differences in design, operation and climate factors. Nutrient retention is a very important objective for constructed wetlands, to avoid eutrophication of aquatic environments receiving their effluents. This study assessed the performance of constructed wetlands in terms of nutrient retention and associated parameters under the humid conditions of Ireland's temperate maritime climate. A review of the performance of 52 constructed wetland sites from 17 local authorities aimed to identify the best performing types of constructed wetlands and the treatment factors determining successful compliance with environmental standards. Data analysis compared effluent results from constructed wetlands with secondary free surface flow or tertiary horizontal subsurface flow, hybrid systems and integrated constructed wetlands with those from small-scale mechanical wastewater treatment plants of the same size class. Nutrient concentrations in effluents of constructed wetlands were negatively correlated (p < .01) with specific area, i.e. the ratio of surface area and population equivalents. The latest generation of integrated constructed wetlands, which had applied design guidelines issued by the Department of the Environment, performed best. Storm management design features improved treatment performance of constructed wetlands significantly (p < .05) for total suspended solids concentrations and exceedance frequency of limit values for total nitrogen. Mechanical wastewater treatment plants, secondary free surface water and tertiary horizontal subsurface flow wetlands showed a very large variance in effluent concentrations for organic and nutrient parameters. E. coli numbers in effluents were lowest for integrated constructed wetlands with an arithmetic mean of 89 MPN/100 ml. Despite Ireland's humid climate, some constructed wetland sites achieved long or frequent periods of zero effluent discharge and thus did not transfer any waterborne pollution to their receptors during these periods. Copyright © 2018 Elsevier Ltd. All rights reserved.

ADC histogram analysis for adrenal tumor histogram analysis of apparent diffusion coefficient in differentiating adrenal adenoma from pheochromocytoma.

PubMed

Umanodan, Tomokazu; Fukukura, Yoshihiko; Kumagae, Yuichi; Shindo, Toshikazu; Nakajo, Masatoyo; Takumi, Koji; Nakajo, Masanori; Hakamada, Hiroto; Umanodan, Aya; Yoshiura, Takashi

2017-04-01

To determine the diagnostic performance of apparent diffusion coefficient (ADC) histogram analysis in diffusion-weighted (DW) magnetic resonance imaging (MRI) for differentiating adrenal adenoma from pheochromocytoma. We retrospectively evaluated 52 adrenal tumors (39 adenomas and 13 pheochromocytomas) in 47 patients (21 men, 26 women; mean age, 59.3 years; range, 16-86 years) who underwent DW 3.0T MRI. Histogram parameters of ADC (b-values of 0 and 200 [ADC 200 ], 0 and 400 [ADC 400 ], and 0 and 800 s/mm 2 [ADC 800 ])-mean, variance, coefficient of variation (CV), kurtosis, skewness, and entropy-were compared between adrenal adenomas and pheochromocytomas, using the Mann-Whitney U-test. Receiver operating characteristic (ROC) curves for the histogram parameters were generated to differentiate adrenal adenomas from pheochromocytomas. Sensitivity and specificity were calculated by using a threshold criterion that would maximize the average of sensitivity and specificity. Variance and CV of ADC 800 were significantly higher in pheochromocytomas than in adrenal adenomas (P < 0.001 and P = 0.001, respectively). With all b-value combinations, the entropy of ADC was significantly higher in pheochromocytomas than in adrenal adenomas (all P ≤ 0.001), and showed the highest area under the ROC curve among the ADC histogram parameters for diagnosing adrenal adenomas (ADC 200 , 0.82; ADC 400 , 0.87; and ADC 800 , 0.92), with sensitivity of 84.6% and specificity of 84.6% (cutoff, ≤2.82) with ADC 200 ; sensitivity of 89.7% and specificity of 84.6% (cutoff, ≤2.77) with ADC 400 ; and sensitivity of 94.9% and specificity of 92.3% (cutoff, ≤2.67) with ADC 800 . ADC histogram analysis of DW MRI can help differentiate adrenal adenoma from pheochromocytoma. 3 J. Magn. Reson. Imaging 2017;45:1195-1203. © 2016 International Society for Magnetic Resonance in Medicine.

A longitudinal study investigating how stroke severity, disability, and physical function the first week post-stroke are associated with walking speed six months post-stroke.

PubMed

Aaslund, Mona Kristin; Moe-Nilssen, Rolf; Gjelsvik, Bente Bassøe; Bogen, Bård; Næss, Halvor; Hofstad, Håkon; Skouen, Jan Sture

2017-12-01

To investigate to which degree stroke severity, disability, and physical function the first week post-stroke are associated with preferred walking speed (PWS) at 6 months. Longitudinal observational study. Participants were recruited from a stroke unit and tested within the first week (baseline) and at 6 months post-stroke. Outcome measures were the National Institutes of Health Stroke Scale (NIHSS), the Barthel Index (BI), modified Rankin Scale (mRS), PWS, Postural Assessment Scale for Stroke (PASS), and the Trunk Impairment Scale modified-Norwegian version. Multiple regression models were used to explore which variables best predict PWS at 6 months, and the Receiver Operating Characteristics (ROC) curves to determine the cutoffs. A total of 132 participants post-stroke were included and subdivided into two groups based on the ability to produce PWS at baseline. For the participants that could produce PWS at baseline (WSB group), PASS, PWS, and age at baseline predicted PWS at 6 months with an explained variance of 0.77. For the participants that could not produce a PWS at baseline (NoWSB group), only PASS predicted PWS at 6 months with an explained variance of 0.49. For the Walking speed at baseline (WSB) group, cutoffs at baseline for walking faster than 0.8 m/s at 6 months were 30.5 points on the PASS, PWS 0.75 m/s, and age 73.5 years. For the NoWSB group, the cutoff for PASS was 20.5 points. PASS, PWS, and age the first week predicted PWS at 6 months post-stroke for participants with the best walking ability, and PASS alone predicted PWS at 6 months post-stroke for participants with the poorest walking ability.

Protocol Analysis of Man-Computer Languages: Design and Preliminary Findings

DTIC Science & Technology

1975-07-01

describes a statistical moael o propot of the exercise. It is one particular model used for analysis of variance which allows us to test the significance of... Body : Congressman Blake will be visiting Camp Smith to confer with J6, J612, and Col. Smith with regard to operation of the pilot project on

43 CFR 3279.10 - When may I request a variance from BLM requirements pertaining to utilization operations?

Code of Federal Regulations, 2014 CFR

2014-10-01

... Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) GEOTHERMAL RESOURCE LEASING Utilization Relief and Appeals § 3279.10 When may I request a... request must include enough information to explain: (1) Why you cannot comply with the requirements; and...

Location, Location, Location: How Would a High-Performing Charter School Network Fare in Different States?

ERIC Educational Resources Information Center

Lozier, Chris; Rotherham, Andrew J.

2011-01-01

In this paper the authors do not examine different operating strategies for charter schools or analyze the impact of their often educationally intensive models on finance. Instead, because public charter schools are funded predominantly by public dollars, they simply ask what impact location--and its associated variances in public funding and the…

Quantum displacement receiver for M-ary phase-shift-keyed coherent states

DOE Office of Scientific and Technical Information (OSTI.GOV)

Izumi, Shuro; Takeoka, Masahiro; Fujiwara, Mikio

2014-12-04

We propose quantum receivers for 3- and 4-ary phase-shift-keyed (PSK) coherent state signals to overcome the standard quantum limit (SQL). Our receiver, consisting of a displacement operation and on-off detectors with or without feedforward, provides an error probability performance beyond the SQL. We show feedforward operations can tolerate the requirement for the detector specifications.

Optical Vector Receiver Operating Near the Quantum Limit

NASA Astrophysics Data System (ADS)

Vilnrotter, V. A.; Lau, C.-W.

2005-05-01

An optical receiver concept for binary signals with performance approaching the quantum limit at low average-signal energies is developed and analyzed. A conditionally nulling receiver that reaches the quantum limit in the absence of background photons has been devised by Dolinar. However, this receiver requires ideal optical combining and complicated real-time shaping of the local field; hence, it tends to be difficult to implement at high data rates. A simpler nulling receiver that approaches the quantum limit without complex optical processing, suitable for high-rate operation, had been suggested earlier by Kennedy. Here we formulate a vector receiver concept that incorporates the Kennedy receiver with a physical beamsplitter, but it also utilizes the reflected signal component to improve signal detection. It is found that augmenting the Kennedy receiver with classical coherent detection at the auxiliary beamsplitter output, and optimally processing the vector observations, always improves on the performance of the Kennedy receiver alone, significantly so at low average-photon rates. This is precisely the region of operation where modern codes approach channel capacity. It is also shown that the addition of background radiation has little effect on the performance of the coherent receiver component, suggesting a viable approach for near-quantum-limited performance in high background environments.

47 CFR 22.579 - Operation of mobile transmitters across U.S.-Canada border.

Code of Federal Regulations, 2010 CFR

2010-10-01

... authority of base stations licensed under this part may receive two-way service while in Canada from... Mobile Operation § 22.579 Operation of mobile transmitters across U.S.-Canada border. Mobile stations licensed by Canada may receive two-way service while in the United States from stations licensed under this...

20 CFR 670.300 - What entities are eligible to receive funds to operate centers and provide training and...

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What entities are eligible to receive funds to operate centers and provide training and operational support services? 670.300 Section 670.300... OF THE WORKFORCE INVESTMENT ACT Funding and Selection of Service Providers § 670.300 What entities...

Evaluation of sampling plans to detect Cry9C protein in corn flour and meal.

PubMed

Whitaker, Thomas B; Trucksess, Mary W; Giesbrecht, Francis G; Slate, Andrew B; Thomas, Francis S

2004-01-01

StarLink is a genetically modified corn that produces an insecticidal protein, Cry9C. Studies were conducted to determine the variability and Cry9C distribution among sample test results when Cry9C protein was estimated in a bulk lot of corn flour and meal. Emphasis was placed on measuring sampling and analytical variances associated with each step of the test procedure used to measure Cry9C in corn flour and meal. Two commercially available enzyme-linked immunosorbent assay kits were used: one for the determination of Cry9C protein concentration and the other for % StarLink seed. The sampling and analytical variances associated with each step of the Cry9C test procedures were determined for flour and meal. Variances were found to be functions of Cry9C concentration, and regression equations were developed to describe the relationships. Because of the larger particle size, sampling variability associated with cornmeal was about double that for corn flour. For cornmeal, the sampling variance accounted for 92.6% of the total testing variability. The observed sampling and analytical distributions were compared with the Normal distribution. In almost all comparisons, the null hypothesis that the Cry9C protein values were sampled from a Normal distribution could not be rejected at 95% confidence limits. The Normal distribution and the variance estimates were used to evaluate the performance of several Cry9C protein sampling plans for corn flour and meal. Operating characteristic curves were developed and used to demonstrate the effect of increasing sample size on reducing false positives (seller's risk) and false negatives (buyer's risk).

Investigations of the Nature and Behavior of Plasma-Density Disturbances That May Impact GPS and Other Transionospheric Systems

DTIC Science & Technology

2002-10-31

association with the High-frequency Active Auroral Research Program ( HAARP ). In addition to a classic riometer and a GPS Total Electron Content (TEC...sensor previously operating at the HAARP site, NWRA also operates a set of Transit receivers for measurements of TEC and scintillation at VHF and UHF...supplementing the receiver at HAARP with a receiver north of the site and an additional receiver installed south of the HAARP site.

12 CFR 324.101 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... quantification system; data management and maintenance system; and control, oversight, and validation system for...-supervised institution's advanced IRB systems, operational risk management processes, operational risk data...-length basis between the seller and the obligor (intercompany accounts receivable and receivables subject...

Scanning tunneling microscope assembly, reactor, and system

DOEpatents

Tao, Feng; Salmeron, Miquel; Somorjai, Gabor A

2014-11-18

An embodiment of a scanning tunneling microscope (STM) reactor includes a pressure vessel, an STM assembly, and three spring coupling objects. The pressure vessel includes a sealable port, an interior, and an exterior. An embodiment of an STM system includes a vacuum chamber, an STM reactor, and three springs. The three springs couple the STM reactor to the vacuum chamber and are operable to suspend the scanning tunneling microscope reactor within the interior of the vacuum chamber during operation of the STM reactor. An embodiment of an STM assembly includes a coarse displacement arrangement, a piezoelectric fine displacement scanning tube coupled to the coarse displacement arrangement, and a receiver. The piezoelectric fine displacement scanning tube is coupled to the coarse displacement arrangement. The receiver is coupled to the piezoelectric scanning tube and is operable to receive a tip holder, and the tip holder is operable to receive a tip.

[Individual variation in the frequency of chromosome aberrations under the influence of chemical mutagens. I. Inter-cultural and inter-individual variations in the effect of mutagens on human lymphocytes].

PubMed

Iakovenko, K N; Tarusina, T O

1976-01-01

The study of the distribution law of human peripheral blood cultures for the sensitivity to thiophosphamide was performed. In the first experiment the blood from one person was used, in the second one the blood was used from different persons. "The percent of aberrant cells" and "the number of chromosome breaks per 100 cells" were scored. The distribution law of the cultures in all the experiments was found to be normal. Analysis of the variances on the percent of aberrant cells showed that the distribution law of the cultures received from one donor corresponded to the binomial one, and that of the cultures received from different donors--to the Poisson's one.

Safety of remifentanil in transsphenoidal surgery: A single-center analysis of 540 patients.

PubMed

Cote, David J; Burke, William T; Castlen, Joseph P; King, Chih H; Zaidi, Hasan A; Smith, Timothy R; Laws, Edward R; Aglio, Linda S

2017-04-01

Although some studies have examined the efficacy and safety of remifentanil in patients undergoing neurosurgical procedures, none has examined its safety in transsphenoidal operations specifically. In this study, all transsphenoidal operations performed by a single author from 2008 to 2015 were retrospectively reviewed to evaluate the safety of remifentanil in a consecutive series of patients. During the study period, 540 transsphenoidal operations were identified. Of these, 443 (82.0%) patients received remifentanil intra-operatively; 97 (18.0%) did not. The two groups were well-matched with regard to demographic categories, comorbidities, and pre-operative medications (p>0.05), except pre-operative tobacco use (p=0.021). Patients were also well-matched with regard to radiographic features and surgical techniques. Patients who received remifentanil were more likely to harbor a macroadenoma (78.1% vs. 67.0%, p=0.025), and had slightly longer anesthesia time on average (269.2minvs. 239.4min, p=0.024). All pathologic diagnoses were well-matched between the two groups, except that patients receiving remifentanil were more likely to harbor a non-functioning adenoma (46.5% vs. 26.8%, p<0.001). Analysis of post-operative complications showed no significant difference between patients who received remifentanil and those who did not, and length of stay and prevalence of ICU stay did not differ between the two groups. In a well-matched series of 540 patients undergoing transsphenoidal surgery, remifentanil was found to be a safe anesthetic adjunct. There were no significant differences in post-operative hospital course or complications in patients who did and did not receive intra-operative remifentanil. Copyright © 2016 Elsevier Ltd. All rights reserved.

Impact of Strategically Located White Matter Hyperintensities on Cognition in Memory Clinic Patients with Small Vessel Disease.

PubMed

Biesbroek, J Matthijs; Weaver, Nick A; Hilal, Saima; Kuijf, Hugo J; Ikram, Mohammad Kamran; Xu, Xin; Tan, Boon Yeow; Venketasubramanian, Narayanaswamy; Postma, Albert; Biessels, Geert Jan; Chen, Christopher P L H

2016-01-01

Studies on the impact of small vessel disease (SVD) on cognition generally focus on white matter hyperintensity (WMH) volume. The extent to which WMH location relates to cognitive performance has received less attention, but is likely to be functionally important. We examined the relation between WMH location and cognition in a memory clinic cohort of patients with sporadic SVD. A total of 167 patients with SVD were recruited from memory clinics. Assumption-free region of interest-based analyses based on major white matter tracts and voxel-wise analyses were used to determine the association between WMH location and executive functioning, visuomotor speed and memory. Region of interest-based analyses showed that WMHs located particularly within the anterior thalamic radiation and forceps minor were inversely associated with both executive functioning and visuomotor speed, independent of total WMH volume. Memory was significantly associated with WMH volume in the forceps minor, independent of total WMH volume. An independent assumption-free voxel-wise analysis identified strategic voxels in these same tracts. Region of interest-based analyses showed that WMH volume within the anterior thalamic radiation explained 6.8% of variance in executive functioning, compared to 3.9% for total WMH volume; WMH volume within the forceps minor explained 4.6% of variance in visuomotor speed and 4.2% of variance in memory, compared to 1.8% and 1.3% respectively for total WMH volume. Our findings identify the anterior thalamic radiation and forceps minor as strategic white matter tracts in which WMHs are most strongly associated with cognitive impairment in memory clinic patients with SVD. WMH volumes in individual tracts explained more variance in cognition than total WMH burden, emphasizing the importance of lesion location when addressing the functional consequences of WMHs.

On the mean and variance of the writhe of random polygons.

PubMed

Portillo, J; Diao, Y; Scharein, R; Arsuaga, J; Vazquez, M

We here address two problems concerning the writhe of random polygons. First, we study the behavior of the mean writhe as a function length. Second, we study the variance of the writhe. Suppose that we are dealing with a set of random polygons with the same length and knot type, which could be the model of some circular DNA with the same topological property. In general, a simple way of detecting chirality of this knot type is to compute the mean writhe of the polygons; if the mean writhe is non-zero then the knot is chiral. How accurate is this method? For example, if for a specific knot type K the mean writhe decreased to zero as the length of the polygons increased, then this method would be limited in the case of long polygons. Furthermore, we conjecture that the sign of the mean writhe is a topological invariant of chiral knots. This sign appears to be the same as that of an "ideal" conformation of the knot. We provide numerical evidence to support these claims, and we propose a new nomenclature of knots based on the sign of their expected writhes. This nomenclature can be of particular interest to applied scientists. The second part of our study focuses on the variance of the writhe, a problem that has not received much attention in the past. In this case, we focused on the equilateral random polygons. We give numerical as well as analytical evidence to show that the variance of the writhe of equilateral random polygons (of length n ) behaves as a linear function of the length of the equilateral random polygon.

On the mean and variance of the writhe of random polygons

PubMed Central

Portillo, J.; Diao, Y.; Scharein, R.; Arsuaga, J.; Vazquez, M.

2013-01-01

We here address two problems concerning the writhe of random polygons. First, we study the behavior of the mean writhe as a function length. Second, we study the variance of the writhe. Suppose that we are dealing with a set of random polygons with the same length and knot type, which could be the model of some circular DNA with the same topological property. In general, a simple way of detecting chirality of this knot type is to compute the mean writhe of the polygons; if the mean writhe is non-zero then the knot is chiral. How accurate is this method? For example, if for a specific knot type K the mean writhe decreased to zero as the length of the polygons increased, then this method would be limited in the case of long polygons. Furthermore, we conjecture that the sign of the mean writhe is a topological invariant of chiral knots. This sign appears to be the same as that of an “ideal” conformation of the knot. We provide numerical evidence to support these claims, and we propose a new nomenclature of knots based on the sign of their expected writhes. This nomenclature can be of particular interest to applied scientists. The second part of our study focuses on the variance of the writhe, a problem that has not received much attention in the past. In this case, we focused on the equilateral random polygons. We give numerical as well as analytical evidence to show that the variance of the writhe of equilateral random polygons (of length n) behaves as a linear function of the length of the equilateral random polygon. PMID:25685182

Prolonged Reduction in Shoulder Strength after Transcutaneous Electrical Nerve Stimulation Treatment of Exercise-Induced Acute Muscle Pain.

PubMed

Butera, Katie A; George, Steven Z; Borsa, Paul A; Dover, Geoffrey C

2018-03-05

Transcutaneous electrical nerve stimulation (TENS) is commonly used for reducing musculoskeletal pain to improve function. However, peripheral nerve stimulation using TENS can alter muscle motor output. Few studies examine motor outcomes following TENS in a human pain model. Therefore, this study investigated the influence of TENS sensory stimulation primarily on motor output (strength) and secondarily on pain and disability following exercise-induced delayed-onset muscle soreness (DOMS). Thirty-six participants were randomized to a TENS treatment, TENS placebo, or control group after completing a standardized DOMS protocol. Measures included shoulder strength, pain, mechanical pain sensitivity, and disability. TENS treatment and TENS placebo groups received 90 minutes of active or sham treatment 24, 48, and 72 hours post-DOMS. All participants were assessed daily. A repeated measures analysis of variance and post-hoc analysis indicated that, compared to the control group, strength remained reduced in the TENS treatment group (48 hours post-DOMS, P < 0.05) and TENS placebo group (48 hours post-DOMS, P < 0.05; 72 hours post-DOMS, P < 0.05). A mixed-linear modeling analysis was conducted to examine the strength (motor) change. Randomization group explained 5.6% of between-subject strength variance (P < 0.05). Independent of randomization group, pain explained 8.9% of within-subject strength variance and disability explained 3.3% of between-subject strength variance (both P < 0.05). While active and placebo TENS resulted in prolonged strength inhibition, the results were nonsignificant for pain. Results indicated that higher pain and higher disability were independently related to decreased strength. Regardless of the impact on pain, TENS, or even the perception of TENS, may act as a nocebo for motor output. © 2018 World Institute of Pain.

Explaining variation in perceived team effectiveness: results from eleven quality improvement collaboratives.

PubMed

Strating, Mathilde M H; Nieboer, Anna P

2013-06-01

Explore effectiveness of 11 collaboratives focusing on 11 different topics, as perceived by local improvement teams and to explore associations with collaborative-, organisational- and team-level factors. Evidence underlying the effectiveness of quality improvement collaboratives is inconclusive and few studies investigated determinants of implementation success. Moreover, most evaluation studies on quality improvement collaboratives are based on one specific topic or quality problem, making it hard to compare across collaboratives addressing different topics. A multiple-case cross-sectional study. Quality improvement teams in 11 quality improvement collaboratives focusing on 11 different topics. Team members received a postal questionnaire at the end of each collaborative. Of the 283 improvement teams, 151 project leaders and 362 team members returned the questionnaire. Analysis of variance revealed that teams varied widely on perceived effectiveness. Especially, members in the Prevention of Malnutrition and Prevention of Medication Errors collaboratives perceived a higher effectiveness than other groups. Multilevel regression analyses showed that educational level of professionals, innovation attributes, organisational support, innovative culture and commitment to change were all significant predictors of perceived effectiveness. In total, 27·9% of the individual-level variance, 57·6% of the team-level variance and 80% of the collaborative-level variance could be explained. The innovation's attributes, organisational support, an innovative team culture and professionals' commitment to change are instrumental to perceived effectiveness. The results support the notion that a layered approach is necessary to achieve improvements in quality of care and provides further insight in the determinants of success of quality improvement collaboratives. Understanding which factors enhance the impact of quality improvement initiatives can help professionals to achieve breakthrough improvement in care delivery to patients on a wide variety of quality problems. © 2012 Blackwell Publishing Ltd.

Reducing the number of reconstructions needed for estimating channelized observer performance

NASA Astrophysics Data System (ADS)

Pineda, Angel R.; Miedema, Hope; Brenner, Melissa; Altaf, Sana

2018-03-01

A challenge for task-based optimization is the time required for each reconstructed image in applications where reconstructions are time consuming. Our goal is to reduce the number of reconstructions needed to estimate the area under the receiver operating characteristic curve (AUC) of the infinitely-trained optimal channelized linear observer. We explore the use of classifiers which either do not invert the channel covariance matrix or do feature selection. We also study the assumption that multiple low contrast signals in the same image of a non-linear reconstruction do not significantly change the estimate of the AUC. We compared the AUC of several classifiers (Hotelling, logistic regression, logistic regression using Firth bias reduction and the least absolute shrinkage and selection operator (LASSO)) with a small number of observations both for normal simulated data and images from a total variation reconstruction in magnetic resonance imaging (MRI). We used 10 Laguerre-Gauss channels and the Mann-Whitney estimator for AUC. For this data, our results show that at small sample sizes feature selection using the LASSO technique can decrease bias of the AUC estimation with increased variance and that for large sample sizes the difference between these classifiers is small. We also compared the use of multiple signals in a single reconstructed image to reduce the number of reconstructions in a total variation reconstruction for accelerated imaging in MRI. We found that AUC estimation using multiple low contrast signals in the same image resulted in similar AUC estimates as doing a single reconstruction per signal leading to a 13x reduction in the number of reconstructions needed.

The Effect of Antifibrinolytic Prophylaxis on Postoperative Outcomes in Patients Undergoing Cardiac Operations

PubMed Central

Koul, Abhinav; Ferraris, Victor; Davenport, Daniel L; Ramaiah, Chandrashekhar

2012-01-01

Antifibrinolytic agents such as aprotinin and epsilon aminocaproic acid limit postoperative bleeding and blood transfusion in patients undergoing cardiac operations using cardiopulmonary bypass (CPB). Recent evidence suggests that these agents have adverse side effects that influence operative mortality and morbidity. We studied postoperative bleeding, transfusion rates, and operative outcomes in our patients in order to assess the efficacy of these agents during cardiac operations requiring CPB. We reviewed records of 520 patients undergoing a variety of cardiac operations between January 2005 and May 2009. We measured multiple variables including pre-operative risk factors, antifibrinolytic agent used, and outcomes of operation, such as measures of bleeding and blood transfusion, as well as serious operative morbidity and mortality. Postoperative bleeding rates varied significantly between patients receiving aprotinin and those receiving aminocaproic acid (P < 0.05). There was an associated 12% decrease in operative site bleeding in aprotinin-treated patients compared with aminocaproic acid. There was no significant difference in the transfusion rates of packed red blood cells between patients receiving aminocaproic acid or aprotinin (P > 0.05), though individuals in the aprotinin group did receive FFP more frequently than patients in the aminocaproic acid group (P < 0.05). There was no significant difference in morbidity and mortality rates between patients in either drug group (P > 0.05). Our study shows that aprotinin is more effective at controlling operative site bleeding than aminocaproic acid. Reduced operative site bleeding did not portend better outcome or differences in transfusion requirements. Aminocaproic acid remains a safe and cost-effective option for antifibrinolytic prophylaxis because of unavailability of aprotinin. PMID:23101999

Forwardly movable assembly for a firearm

DOEpatents

Crandall, David L [Idaho Falls, ID; Watson, Richard W [Blackfoot, ID

2007-06-05

A forwardly movable assembly for a firearm, the forwardly movable assembly adapted to be disposed in operative relationship relative to the other operative parts of a firearm, the firearm having in operative relationship each with one or more of the others: a barrel, a receiver, and at least one firing mechanism; the forwardly movable assembly comprising: the barrel and the receiver operatively connected with each other; a movable hand support structure to which at least one of the barrel and the receiver is connected, the barrel being movable therewith, the movable hand support structure being adapted to be gripped by an operator of the firearm; the forwardly movable assembly being adapted to be moved forward by an operator upon gripping the movable hand support structure and manually maneuvering the hand support structure forwardly; and, as the forwardly movable assembly is moved forwardly, the firing mechanism is completely disengaged therefrom and held substantially stationary relative thereto.

Dancing with the Muses: dissociation and flow.

PubMed

Thomson, Paula; Jaque, S Victoria

2012-01-01

This study investigated dissociative psychological processes and flow (dispositional and state) in a group of professional and pre-professional dancers (n=74). In this study, high scores for global (Mdn=4.14) and autotelic (Mdn=4.50) flow suggest that dancing was inherently integrating and rewarding, although 17.6% of the dancers were identified as possibly having clinical levels of dissociation (Dissociative Experiences Scale-Taxon cutoff score≥20). The results of the multivariate analysis of variance indicated that subjects with high levels of dissociation had significantly lower levels of global flow (p<.05). Stepwise linear regression analyses demonstrated that dispositional flow negatively predicted the dissociative constructs of depersonalization and taxon (p<.05) but did not significantly predict the variance in absorption/imagination (p>.05). As hypothesized, dissociation and flow seem to operate as different mental processes.

En face projection imaging of the human choroidal layers with tracking SLO and swept source OCT angiography methods

NASA Astrophysics Data System (ADS)

Gorczynska, Iwona; Migacz, Justin; Zawadzki, Robert J.; Sudheendran, Narendran; Jian, Yifan; Tiruveedhula, Pavan K.; Roorda, Austin; Werner, John S.

2015-07-01

We tested and compared the capability of multiple optical coherence tomography (OCT) angiography methods: phase variance, amplitude decorrelation and speckle variance, with application of the split spectrum technique, to image the choroiretinal complex of the human eye. To test the possibility of OCT imaging stability improvement we utilized a real-time tracking scanning laser ophthalmoscopy (TSLO) system combined with a swept source OCT setup. In addition, we implemented a post- processing volume averaging method for improved angiographic image quality and reduction of motion artifacts. The OCT system operated at the central wavelength of 1040nm to enable sufficient depth penetration into the choroid. Imaging was performed in the eyes of healthy volunteers and patients diagnosed with age-related macular degeneration.

Implementation of foot thermometry plus mHealth to prevent diabetic foot ulcers: study protocol for a randomized controlled trial.

PubMed

Lazo-Porras, Maria; Bernabe-Ortiz, Antonio; Sacksteder, Katherine A; Gilman, Robert H; Malaga, German; Armstrong, David G; Miranda, J Jaime

2016-04-19

Diabetic foot neuropathy (DFN) is one of the most important complications of diabetes mellitus; its early diagnosis and intervention can prevent foot ulcers and the need for amputation. Thermometry, measuring the temperature of the feet, is a promising emerging modality for diabetic foot ulcer prevention. However, patient compliance with at-home monitoring is concerning. Delivering messages to remind patients to perform thermometry and foot care might be helpful to guarantee regular foot monitoring. This trial was designed to compare the incidence of diabetic foot ulcers (DFUs) between participants who receive thermometry alone and those who receive thermometry as well as mHealth (SMS and voice messaging) over a year-long study period. This is an evaluator-blinded, randomized, 12-month trial. Individuals with a diagnosis of type 2 diabetes mellitus, aged between 18-80 years, having a present dorsalis pedis pulse in both feet, are in risk group 2 or 3 using the diabetic foot risk classification system (as specified by the International Working Group on the Diabetic Foot), have an operating cell phone or a caregiver with an operating cell phone, and have the ability to provide informed consent will be eligible to participate in the study. Recruitment will be performed in diabetes outpatient clinics at two Ministry of Health tertiary hospitals in Lima, Peru. participants in both groups will receive education about foot care at the beginning of the study and they will be provided with a thermometry device (TempStat™). TempStat™ is a tool that captures a thermal image of the feet, which, depending on the temperature of the feet, shows different colors. In this study, if a participant notes a single yellow image or variance between one foot and the contralateral foot, they will be prompted to notify a nurse to evaluate their activity within the previous 2 weeks and make appropriate recommendations. In addition to thermometry, participants in the intervention arm will receive an mHealth component in the form of SMS and voice messages as reminders to use the thermometry device, and instructions to promote foot care. the primary outcome is foot ulceration, evaluated by a trained nurse, occurring at any point during the study. This study has two principal contributions towards the prevention of DFU. First, the introduction of messages to promote self-management of diabetes foot care as well as using reminders as a strategy to improve adherence to daily home-based measurements. Secondly, the implementation of a thermometry-based strategy complemented by SMS and voice messages in an LMIC setting, with wider implications for scalability. This study is registered in ClinicalTrials.gov: Identifier NCT02373592 .

Post-operative bracing after pedicle screw fixation for thoracolumbar burst fractures: A cost-effectiveness study.

PubMed

Piazza, Matthew; Sinha, Saurabh; Agarwal, Prateek; Mallela, Arka; Nayak, Nikhil; Schuster, James; Stein, Sherman

2017-11-01

While frequently prescribed to patients following fixation for spine trauma, the utility of spinal orthoses during the post-operative period is poorly described in the literature. In this study, we calculated rates of reoperation and performed a decision analysis to determine the utility of bracing following pedicle screw fixation for thoracic and lumbar burst fractures. Pubmed was searched for articles published between 2005 and 2015 for terms related to pedicle screw fixation of thoracolumbar fractures. Additionally, a database of neurosurgical patients operated on within the authors institution was also used in the analysis. Incidences of significant adverse events (wound revision for either dehiscence or infection or re-operation for non-union or instability due to hardware failure) were determined. Pooled means and variances of reported parameters were obtained using a random-effects, inverse variance meta-analytic model for observational data. Utilities for surgical outcome and complications were assigned using previously published values. Of the 225 abstracts reviewed, 48 articles were included in the study, yielding a total of 1957 patients. After including patients from the institutional registry, together a total of 2081 patients were included in the final analysis, 1328 of whom were braced. Non-braced patients were older then braced patients, although this only approached significance (p=0.051). Braced patients had significantly lower rates of re-operation for non-union or clinically significant hardware failure (1.3% vs. 1.8%, p<0.001) although the groups had comparable rates of operative wound dehiscence and infection (p=1.000). These two approaches yielded comparable utility scores (p=0.120). Costs between braced and non-braced patients were comparable excluding the cost of the brace (p=0.256); hence, the added cost of the brace suggests that bracing post-operatively is not a cost effective measure. Bracing following operative stabilization of thoracolumbar fracture does not significantly improve stability, nor does it increase wound complications. Moreover, our data suggests that post-operative bracing may not be a cost-effective measure. Copyright © 2017. Published by Elsevier Ltd.

Feeling fat in eating disorders: Testing the unique relationships between feeling fat and measures of disordered eating in anorexia nervosa and bulimia nervosa.

PubMed

Linardon, Jake; Phillipou, Andrea; Castle, David; Newton, Richard; Harrison, Philippa; Cistullo, Leonardo L; Griffiths, Scott; Hindle, Annemarie; Brennan, Leah

2018-06-01

Although widely discussed in theories of eating disorders, the experience of "feeling fat" in this population has received little research attention. This study tested the unique relationships between feeling fat and measures of problematic eating behaviours and attitudes. Data were analysed from individuals with anorexia nervosa (AN; n = 123) and bulimia nervosa (BN; n = 51). Correlations revealed considerable unshared variance between feeling fat and shape and weight over-evaluation and depressive symptoms. Moreover, when over-evaluation and depressive symptoms were controlled, feeling fat predicted unique variance in restraint and eating concerns. Findings offer some support for the idea that feeling fat is a distinct and important component of body image concerns in eating disorders. Further research that develops a standardized measure of feeling fat is required. Further research that examines whether feeling fat is an important treatment mechanism is also needed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Teacher and child predictors of achieving IEP goals of children with autism.

PubMed

Ruble, Lisa; McGrew, John H

2013-12-01

It is encouraging that children with autism show a strong response to early intervention, yet more research is needed for understanding the variability in responsiveness to specialized programs. Treatment predictor variables from 47 teachers and children who were randomized to receive the COMPASS intervention (Ruble et al. in The collaborative model for promoting competence and success for students with ASD. Springer, New York, 2012a) were analyzed. Predictors evaluated against child IEP goal attainment included child, teacher, intervention practice, and implementation practice variables based on an implementation science framework (Dunst and Trivette in J Soc Sci 8:143-148, 2012). Findings revealed one child (engagement), one teacher (exhaustion), two intervention quality (IEP quality for targeted and not targeted elements), and no implementation quality variables accounted for variance in child outcomes when analyzed separately. When the four significant variables were compared against each other in a single regression analysis, IEP quality accounted for one quarter of the variance in child outcomes.

Teacher and Child Predictors of Achieving IEP Goals of Children with Autism

PubMed Central

Ruble, Lisa; McGrew, John H.

2013-01-01

It is encouraging that children with autism show a strong response to early intervention, yet more research is needed for understanding the variability in responsiveness to specialized programs. Treatment predictor variables from 47 teachers and children who were randomized to receive the COMPASS intervention (Ruble et al. in The collaborative model for promoting competence and success for students with ASD. Springer, New York, 2012a) were analyzed. Predictors evaluated against child IEP goal attainment included child, teacher, intervention practice, and implementation practice variables based on an implementation science framework (Dunst and Trivette in J Soc Sci 8:143–148, 2012). Findings revealed one child (engagement), one teacher (exhaustion), two intervention quality (IEP quality for targeted and not targeted elements), and no implementation quality variables accounted for variance in child outcomes when analyzed separately. When the four significant variables were compared against each other in a single regression analysis, IEP quality accounted for one quarter of the variance in child outcomes. PMID:23838728

Predictors of psychological well-being in a diverse sample of HIV-positive patients receiving highly active antiretroviral therapy.

PubMed

Safren, Steven A; Radomsky, Adam S; Otto, Michael W; Salomon, Elizabeth

2002-01-01

The purpose of the present study was to identify variables relevant to psychological well-being in HIV patients receiving highly active antiretroviral therapy (HAART). Multiple stressors accompany living with HIV while managing a HAART regimen. However, a variety of cognitive and behavioral variables can protect against or augment the deleterious effects of stress in this population. The authors hypothesized that satisfaction with social support, coping styles, and maladaptive attributions about HIV would explain more variance in psychological well-being than stressful life events per se. Participants were individuals with HIV receiving antiretroviral therapy-either starting a new HAART regimen or having difficulties adhering to their current regimen. Satisfaction with social support, coping styles, and punishment beliefs about HIV were uniquely associated with depression, quality of life, and self-esteem over and above the effects of stressful life events. These results provide support for continued psychosocial interventions that target these variables among patients with HIV.

The Operations Process

DTIC Science & Technology

2010-03-26

important events receive the most attention. Ensures that absentees and flank units receive changes to the operation order. Transmits changes to them...York: Vintage Books, 1991. Fuller, J. F. C. Generalship: Its Diseases and Their Cure . Harrisburg, PA: Military Service Publishing Co., 1936

12 CFR 217.101 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... management and maintenance system; and control, oversight, and validation system for credit risk of wholesale... advanced IRB systems, operational risk management processes, operational risk data and assessment systems... the seller and the obligor (intercompany accounts receivable and receivables subject to contra...

Developing the design of a continuous national health survey for New Zealand

PubMed Central

2013-01-01

Background A continuously operating survey can yield advantages in survey management, field operations, and the provision of timely information for policymakers and researchers. We describe the key features of the sample design of the New Zealand (NZ) Health Survey, which has been conducted on a continuous basis since mid-2011, and compare to a number of other national population health surveys. Methods A number of strategies to improve the NZ Health Survey are described: implementation of a targeted dual-frame sample design for better Māori, Pacific, and Asian statistics; movement from periodic to continuous operation; use of core questions with rotating topic modules to improve flexibility in survey content; and opportunities for ongoing improvements and efficiencies, including linkage to administrative datasets. Results and discussion The use of disproportionate area sampling and a dual frame design resulted in reductions of approximately 19%, 26%, and 4% to variances of Māori, Pacific and Asian statistics respectively, but at the cost of a 17% increase to all-ethnicity variances. These were broadly in line with the survey’s priorities. Respondents provided a high degree of cooperation in the first year, with an adult response rate of 79% and consent rates for data linkage above 90%. Conclusions A combination of strategies tailored to local conditions gives the best results for national health surveys. In the NZ context, data from the NZ Census of Population and Dwellings and the Electoral Roll can be used to improve the sample design. A continuously operating survey provides both administrative and statistical advantages. PMID:24364838

Generation of a Parabolic Trough Collector Efficiency Curve from Separate Measurements of Outdoor Optical Efficiency and Indoor Receiver Heat Loss

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kutscher, C.; Burkholder, F.; Stynes, J. K.

2012-02-01

The thermal efficiency of a parabolic trough collector is a function of both the fraction of direct normal radiation absorbed by the receiver (the optical efficiency) and the heat lost to the environment when the receiver is at operating temperature. The thermal efficiency can be determined by testing the collector under actual operating conditions or by separately measuring these two components. This paper describes how outdoor measurement of the optical efficiency is combined with laboratory measurements of receiver heat loss to obtain the thermal efficiency curve. This paper describes this approach and also makes the case that there are advantagesmore » to plotting collector efficiency versus the difference between the operating temperature and the ambient temperature at which the receiver heat loss was measured divided by radiation to a fractional power (on the order of 1/3 but obtained via data regression) - as opposed to the difference between operating and ambient temperatures divided by the radiation. The results are shown to be robust over wide ranges of ambient temperature, sky temperature, and wind speed.« less

Methods for Processing and Interpretation of AIS Signals Corrupted by Noise and Packet Collisions

NASA Astrophysics Data System (ADS)

Poļevskis, J.; Krastiņš, M.; Korāts, G.; Skorodumovs, A.; Trokšs, J.

2012-01-01

The authors deal with the operation of Automatic Identification System (AIS) used in the marine traffic monitoring to broadcast messages containing information about the vessel: id, payload, size, speed, destination etc., meant primarily for avoidance of ship collisions. To extend the radius of AIS operation, it is envisaged to dispose its receivers on satellites. However, in space, due to a large coverage area, interfering factors are especially pronounced - such as packet collision, Doppler's shift and noise impact on AIS message receiving, pre-processing and decoding. To assess the quality of an AIS receiver's operation, a test was carried out in which, varying automatically frequency, amplitude, noise, and other parameters, the data on the ability of the receiver's ability to decode AIS signals are collected. In the work, both hardware- and software-based AIS decoders were tested. As a result, quite satisfactory statistics has been gathered - both on the common and the differing features of such decoders when operating in space. To obtain reliable data on the software-defined radio AIS receivers, further research is envisaged.

Histogram Analysis of Apparent Diffusion Coefficients for Occult Tonsil Cancer in Patients with Cervical Nodal Metastasis from an Unknown Primary Site at Presentation.

PubMed

Choi, Young Jun; Lee, Jeong Hyun; Kim, Hye Ok; Kim, Dae Yoon; Yoon, Ra Gyoung; Cho, So Hyun; Koh, Myeong Ju; Kim, Namkug; Kim, Sang Yoon; Baek, Jung Hwan

2016-01-01

To explore the added value of histogram analysis of apparent diffusion coefficient (ADC) values over magnetic resonance (MR) imaging and fluorine 18 ((18)F) fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) for the detection of occult palatine tonsil squamous cell carcinoma (SCC) in patients with cervical nodal metastasis from a cancer of an unknown primary site. The institutional review board approved this retrospective study, and the requirement for informed consent was waived. Differences in the bimodal histogram parameters of the ADC values were assessed among occult palatine tonsil SCC (n = 19), overt palatine tonsil SCC (n = 20), and normal palatine tonsils (n = 20). One-way analysis of variance was used to analyze differences among the three groups. Receiver operating characteristic curve analysis was used to determine the best differentiating parameters. The increased sensitivity of histogram analysis over MR imaging and (18)F-FDG PET/CT for the detection of occult palatine tonsil SCC was evaluated as added value. Histogram analysis showed statistically significant differences in the mean, standard deviation, and 50th and 90th percentile ADC values among the three groups (P < .0045). Occult palatine tonsil SCC had a significantly higher standard deviation for the overall curves, mean and standard deviation of the higher curves, and 90th percentile ADC value, compared with normal palatine tonsils (P < .0167). Receiver operating characteristic curve analysis showed that the standard deviation of the overall curve best delineated occult palatine tonsil SCC from normal palatine tonsils, with a sensitivity of 78.9% (15 of 19 patients) and a specificity of 60% (12 of 20 patients). The added value of ADC histogram analysis was 52.6% over MR imaging alone and 15.8% over combined conventional MR imaging and (18)F-FDG PET/CT. Adding ADC histogram analysis to conventional MR imaging can improve the detection sensitivity for occult palatine tonsil SCC in patients with a cervical nodal metastasis originating from a cancer of an unknown primary site. © RSNA, 2015.

Thermal resistance model for CSP central receivers

NASA Astrophysics Data System (ADS)

de Meyer, O. A. J.; Dinter, F.; Govender, S.

2016-05-01

The receiver design and heliostat field aiming strategy play a vital role in the heat transfer efficiency of the receiver. In molten salt external receivers, the common operating temperature of the heat transfer fluid or molten salt ranges between 285°C to 565°C. The optimum output temperature of 565°C is achieved by adjusting the mass flow rate of the molten salt through the receiver. The reflected solar radiation onto the receiver contributes to the temperature rise in the molten salt by means of heat transfer. By investigating published work on molten salt external receiver operating temperatures, corresponding receiver tube surface temperatures and heat losses, a model has been developed to obtain a detailed thermographic representation of the receiver. The steady state model uses a receiver flux map as input to determine: i) heat transfer fluid mass flow rate through the receiver to obtain the desired molten salt output temperature of 565°C, ii) receiver surface temperatures iii) receiver tube temperatures iv) receiver efficiency v) pressure drop across the receiver and vi) corresponding tube strain per panel.

20 CFR 670.300 - What entities are eligible to receive funds to operate centers and provide training and...

Code of Federal Regulations, 2014 CFR

2014-04-01

... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false What entities are eligible to receive funds to operate centers and provide training and operational support services? 670.300 Section 670.300... UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Funding and Selection of Service Providers § 670.300 What...

Improvement of Hungarian Joint Terminal Attack Program

DTIC Science & Technology

2013-06-13

LST Laser Spot Tracker NVG Night Vision Goggle ROMAD Radio Operator Maintainer and Driver ROVER Remotely Operated Video Enhanced Receiver TACP...visual target designation. The other component consists of a laser spot tracker (LST), which identifies targets by tracking laser energy reflecting...capability for every type of night time missions, laser spot tracker for laser spot search missions, remotely operated video enhanced receiver

Principal component of explained variance: An efficient and optimal data dimension reduction framework for association studies.

PubMed

Turgeon, Maxime; Oualkacha, Karim; Ciampi, Antonio; Miftah, Hanane; Dehghan, Golsa; Zanke, Brent W; Benedet, Andréa L; Rosa-Neto, Pedro; Greenwood, Celia Mt; Labbe, Aurélie

2018-05-01

The genomics era has led to an increase in the dimensionality of data collected in the investigation of biological questions. In this context, dimension-reduction techniques can be used to summarise high-dimensional signals into low-dimensional ones, to further test for association with one or more covariates of interest. This paper revisits one such approach, previously known as principal component of heritability and renamed here as principal component of explained variance (PCEV). As its name suggests, the PCEV seeks a linear combination of outcomes in an optimal manner, by maximising the proportion of variance explained by one or several covariates of interest. By construction, this method optimises power; however, due to its computational complexity, it has unfortunately received little attention in the past. Here, we propose a general analytical PCEV framework that builds on the assets of the original method, i.e. conceptually simple and free of tuning parameters. Moreover, our framework extends the range of applications of the original procedure by providing a computationally simple strategy for high-dimensional outcomes, along with exact and asymptotic testing procedures that drastically reduce its computational cost. We investigate the merits of the PCEV using an extensive set of simulations. Furthermore, the use of the PCEV approach is illustrated using three examples taken from the fields of epigenetics and brain imaging.

WWSSF - a worldwide study on radioisotopic renal split function: reproducibility of renal split function assessment in children.

PubMed

Geist, Barbara Katharina; Dobrozemsky, Georg; Samal, Martin; Schaffarich, Michael P; Sinzinger, Helmut; Staudenherz, Anton

2015-12-01

The split or differential renal function is the most widely accepted quantitative parameter derived from radionuclide renography. To examine the intercenter variance of this parameter, we designed a worldwide round robin test. Five selected dynamic renal studies have been distributed all over the world by e-mail. Three of these studies are anonymized patient data acquired using the EANM standardized protocol and two studies are phantom studies. In a simple form, individual participants were asked to measure renal split function as well as to provide additional information such as data analysis software, positioning of background region of interest, or the method of calculation. We received the evaluation forms from 34 centers located in 21 countries. The analysis of the round robin test yielded an overall z-score of 0.3 (a z-score below 1 reflecting a good result). However, the z-scores from several centers were unacceptably high, with values greater than 3. In particular, the studies with impaired renal function showed a wide variance. A wide variance in the split renal function was found in patients with impaired kidney function. This study indicates the ultimate importance of quality control and standardization of the measurement of the split renal function. It is especially important with respect to the commonly accepted threshold for significant change in split renal function by 10%.

An Adaptive Moving Target Imaging Method for Bistatic Forward-Looking SAR Using Keystone Transform and Optimization NLCS.

PubMed

Li, Zhongyu; Wu, Junjie; Huang, Yulin; Yang, Haiguang; Yang, Jianyu

2017-01-23

Bistatic forward-looking SAR (BFSAR) is a kind of bistatic synthetic aperture radar (SAR) system that can image forward-looking terrain in the flight direction of an aircraft. Until now, BFSAR imaging theories and methods for a stationary scene have been researched thoroughly. However, for moving-target imaging with BFSAR, the non-cooperative movement of the moving target induces some new issues: (I) large and unknown range cell migration (RCM) (including range walk and high-order RCM); (II) the spatial-variances of the Doppler parameters (including the Doppler centroid and high-order Doppler) are not only unknown, but also nonlinear for different point-scatterers. In this paper, we put forward an adaptive moving-target imaging method for BFSAR. First, the large and unknown range walk is corrected by applying keystone transform over the whole received echo, and then, the relationships among the unknown high-order RCM, the nonlinear spatial-variances of the Doppler parameters, and the speed of the mover, are established. After that, using an optimization nonlinear chirp scaling (NLCS) technique, not only can the unknown high-order RCM be accurately corrected, but also the nonlinear spatial-variances of the Doppler parameters can be balanced. At last, a high-order polynomial filter is applied to compress the whole azimuth data of the moving target. Numerical simulations verify the effectiveness of the proposed method.

Multi-mode radio frequency device

DOEpatents

Gilbert, Ronald W [Morgan Hill, CA; Carrender, Curtis Lee [Morgan Hill, CA; Anderson, Gordon A [Benton City, WA; Steele, Kerry D [Kennewick, WA

2007-02-13

A transponder device having multiple modes of operation, such as an active mode and a passive mode, wherein the modes of operation are selected in response to the strength of a received radio frequency signal. A communication system is also provided having a transceiver configured to transmit a radio frequency signal and to receive a responsive signal, and a transponder configured to operate in a plurality of modes and to activate modes of operation in response to the radio frequency signal. Ideally, each mode of operation is activated and deactivated independent of the other modes, although two or more modes may be concurrently operational.

A 10-MWe solar-thermal central-receiver pilot plant: Solar facilities design integration. Plant operating/training manual (RADL-Item 2-36)

NASA Astrophysics Data System (ADS)

1982-07-01

Plant and system level operating instructions are provided for the Barstow Solar Pilot Plant. Individual status instructions are given that identify plant conditions, process controller responsibilities, process conditions and control accuracies, operating envelopes, and operator cautions appropriate to the operating condition. Transition operating instructions identify the sequence of activities to be carried out to accomplish the indicated transition. Most transitions involve the startup or shutdown of an individual flowpath. Background information is provided on collector field operations, and the heliostat groupings and specific commands used in support receiver startup are defined.

Variance in Dominant Grain Size Across the Mississippi River Delta

NASA Astrophysics Data System (ADS)

Miller, K. L.; Chamberlain, E. L.; Esposito, C. R.; Wagner, R. W.; Mohrig, D. C.

2016-02-01

Proposals to restore coastal Louisiana often center on Mississippi River diversion projects wherein water and sediment are routed into wetlands and shallow waters in an effort to build land. Successful design and implementation of diversions will include consideration of behavior and characteristics of sediment, both in the river and in the receiving basin. The Mississippi River sediment load is primarily mud (roughly 75%), with the remainder being very-fine to medium sand or organic detritus. The dominance of muds leads many to suggest that diversions should focus on capturing the mud fraction despite the smaller size and longer settling times required for these particles compared to sand; others believe that sand should be the focus. We present a systemic analysis of the texture of land-building sediment in the Mississippi Delta using borehole data from various depositional environments representing a range of spatial scales, system ages, and fluvial and basin characteristics. We include subdelta-scale data from the incipient Wax Lake Delta and from the distal plain of the abandoned Lafourche subdelta, as well as crevasse-scale data from modern Cubit's Gap and the Attakapas splay, an inland Lafourche crevasse. Comparison of these sites demonstrates a large variance in the volumetric mud to sand ratios across the system. We consider the differences to be emblematic of the various forcings on each lobe as it formed and suggest that the most efficient building block for a diversion is a function of the receiving basin and is not uniform across the entire delta.

47 CFR 97.121 - Restricted operation.

Code of Federal Regulations, 2013 CFR

2013-10-01

... station causes general interference to the reception of transmissions from stations operating in the domestic broadcast service when receivers of good engineering design, including adequate selectivity characteristics, are used to receive such transmissions, and this fact is made known to the amateur station...

47 CFR 97.121 - Restricted operation.

Code of Federal Regulations, 2012 CFR

2012-10-01

... station causes general interference to the reception of transmissions from stations operating in the domestic broadcast service when receivers of good engineering design, including adequate selectivity characteristics, are used to receive such transmissions, and this fact is made known to the amateur station...

47 CFR 97.121 - Restricted operation.

Code of Federal Regulations, 2014 CFR

2014-10-01

... station causes general interference to the reception of transmissions from stations operating in the domestic broadcast service when receivers of good engineering design, including adequate selectivity characteristics, are used to receive such transmissions, and this fact is made known to the amateur station...

47 CFR 97.121 - Restricted operation.

Code of Federal Regulations, 2010 CFR

2010-10-01

... station causes general interference to the reception of transmissions from stations operating in the domestic broadcast service when receivers of good engineering design, including adequate selectivity characteristics, are used to receive such transmissions, and this fact is made known to the amateur station...

47 CFR 97.121 - Restricted operation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... station causes general interference to the reception of transmissions from stations operating in the domestic broadcast service when receivers of good engineering design, including adequate selectivity characteristics, are used to receive such transmissions, and this fact is made known to the amateur station...

Relationships among Factors in New Officer Effectiveness Report System. Final Report for Period 15 December 1975-30 April 1978.

ERIC Educational Resources Information Center

Bottenberg, Robert A.

To investigate operating characteristics of performance factors and the evaluation of potential ratings for new officers, an analysis of controlled effectiveness for 9,230 lieutenant colonels was performed. The study was done to determine whether performance factor variance was so restricted that the performance factors would not provide useful…

Non-operative management (NOM) of blunt hepatic trauma: 80 cases.

PubMed

Özoğul, Bünyami; Kısaoğlu, Abdullah; Aydınlı, Bülent; Öztürk, Gürkan; Bayramoğlu, Atıf; Sarıtemur, Murat; Aköz, Ayhan; Bulut, Özgür Hakan; Atamanalp, Sabri Selçuk

2014-03-01

Liver is the most frequently injured organ upon abdominal trauma. We present a group of patients with blunt hepatic trauma who were managed without any invasive diagnostic tools and/or surgical intervention. A total of 80 patients with blunt liver injury who were hospitalized to the general surgery clinic or other clinics due to the concomitant injuries were followed non-operatively. The normally distributed numeric variables were evaluated by Student's t-test or one way analysis of variance, while non-normally distributed variables were analyzed by Mann-Whitney U-test or Kruskal-Wallis variance analysis. Chi-square test was also employed for the comparison of categorical variables. Statistical significance was assumed for p<0.05. There was no significant relationship between patients' Hgb level and liver injury grade, outcome, and mechanism of injury. Also, there was no statistical relationship between liver injury grade, outcome, and mechanism of injury and ALT levels as well as AST level. There was no mortality in any of the patients. During the last quarter of century, changes in the diagnosis and treatment of liver injury were associated with increased survival. NOM of liver injury in patients with stable hemodynamics and hepatic trauma seems to be the gold standard.

Ibuprofen timing for hand surgery in ambulatory care

PubMed Central

Giuliani, Enrico; Bianchi, Anna; Marcuzzi, Augusto; Landi, Antonio; Barbieri, Alberto

2015-01-01

OBJECTIVE: To evaluate the effect of pre-operative administration of ibuprofen on post-operative pain control vs. early post-operative administration for hand surgery procedures performed under local anaesthesia in ambulatory care. METHODS: Candidates to trigger finger release by De Quervain tenosynovitis and carpal tunnel operation under local anesthesia were enrolled in the study. Group A received 400 mg ibuprofen before the operation and placebo after the procedure; group B received placebo before the operation and ibuprofen 400 mg at the end of the procedure; both groups received ibuprofen 400 mg every 6h thereafter. Visual analogue scale (VAS) was measured at fixed times before and every 6h after surgery, for a total follow-up of 18h. RESULTS: Groups were similar according to age, gender and type of surgery. Median VAS values did not produce any statistical significance, while there was a statistically significant difference on pre-operative and early post-operative VAS values between groups (A -8.53 mm vs. B 3.36 mm, p=0.0085). CONCLUSION: Average pain levels were well controlled by local anesthesia and post-operative ibuprofen analgesia. Pre-operative ibuprofen administration can contribute to improve early pain management. Level of Evidence II, Therapeutic Studies. PMID:26327799

Performance of DBS-Radio using concatenated coding and equalization

NASA Technical Reports Server (NTRS)

Gevargiz, J.; Bell, D.; Truong, L.; Vaisnys, A.; Suwitra, K.; Henson, P.

1995-01-01

The Direct Broadcast Satellite-Radio (DBS-R) receiver is being developed for operation in a multipath Rayleigh channel. This receiver uses equalization and concatenated coding, in addition to open loop and closed loop architectures for carrier demodulation and symbol synchronization. Performance test results of this receiver are presented in both AWGN and multipath Rayleigh channels. Simulation results show that the performance of the receiver operating in a multipath Rayleigh channel is significantly improved by using equalization. These results show that fractional-symbol equalization offers a performance advantage over full symbol equalization. Also presented is the base-line performance of the DBS-R receiver using concatenated coding and interleaving.

Influence of anisotropic turbulence on the orbital angular momentum modes of Hermite-Gaussian vortex beam in the ocean.

PubMed

Li, Ye; Yu, Lin; Zhang, Yixin

2017-05-29

Applying the angular spectrum theory, we derive the expression of a new Hermite-Gaussian (HG) vortex beam. Based on the new Hermite-Gaussian (HG) vortex beam, we establish the model of the received probability density of orbital angular momentum (OAM) modes of this beam propagating through a turbulent ocean of anisotropy. By numerical simulation, we investigate the influence of oceanic turbulence and beam parameters on the received probability density of signal OAM modes and crosstalk OAM modes of the HG vortex beam. The results show that the influence of oceanic turbulence of anisotropy on the received probability of signal OAM modes is smaller than isotropic oceanic turbulence under the same condition, and the effect of salinity fluctuation on the received probability of the signal OAM modes is larger than the effect of temperature fluctuation. In the strong dissipation of kinetic energy per unit mass of fluid and the weak dissipation rate of temperature variance, we can decrease the effects of turbulence on the received probability of signal OAM modes by selecting a long wavelength and a larger transverse size of the HG vortex beam in the source's plane. In long distance propagation, the HG vortex beam is superior to the Laguerre-Gaussian beam for resisting the destruction of oceanic turbulence.

Statistics 101 for Radiologists.

PubMed

Anvari, Arash; Halpern, Elkan F; Samir, Anthony E

2015-10-01

Diagnostic tests have wide clinical applications, including screening, diagnosis, measuring treatment effect, and determining prognosis. Interpreting diagnostic test results requires an understanding of key statistical concepts used to evaluate test efficacy. This review explains descriptive statistics and discusses probability, including mutually exclusive and independent events and conditional probability. In the inferential statistics section, a statistical perspective on study design is provided, together with an explanation of how to select appropriate statistical tests. Key concepts in recruiting study samples are discussed, including representativeness and random sampling. Variable types are defined, including predictor, outcome, and covariate variables, and the relationship of these variables to one another. In the hypothesis testing section, we explain how to determine if observed differences between groups are likely to be due to chance. We explain type I and II errors, statistical significance, and study power, followed by an explanation of effect sizes and how confidence intervals can be used to generalize observed effect sizes to the larger population. Statistical tests are explained in four categories: t tests and analysis of variance, proportion analysis tests, nonparametric tests, and regression techniques. We discuss sensitivity, specificity, accuracy, receiver operating characteristic analysis, and likelihood ratios. Measures of reliability and agreement, including κ statistics, intraclass correlation coefficients, and Bland-Altman graphs and analysis, are introduced. © RSNA, 2015.

Evidence for the contribution of a threshold retrieval process to semantic memory.

PubMed

Kempnich, Maria; Urquhart, Josephine A; O'Connor, Akira R; Moulin, Chris J A

2017-10-01

It is widely held that episodic retrieval can recruit two processes: a threshold context retrieval process (recollection) and a continuous signal strength process (familiarity). Conversely the processes recruited during semantic retrieval are less well specified. We developed a semantic task analogous to single-item episodic recognition to interrogate semantic recognition receiver-operating characteristics (ROCs) for a marker of a threshold retrieval process. We fitted observed ROC points to three signal detection models: two models typically used in episodic recognition (unequal variance and dual-process signal detection models) and a novel dual-process recollect-to-reject (DP-RR) signal detection model that allows a threshold recollection process to aid both target identification and lure rejection. Given the nature of most semantic questions, we anticipated the DP-RR model would best fit the semantic task data. Experiment 1 (506 participants) provided evidence for a threshold retrieval process in semantic memory, with overall best fits to the DP-RR model. Experiment 2 (316 participants) found within-subjects estimates of episodic and semantic threshold retrieval to be uncorrelated. Our findings add weight to the proposal that semantic and episodic memory are served by similar dual-process retrieval systems, though the relationship between the two threshold processes needs to be more fully elucidated.

Factors that influence the radiofrequency power output of GSM mobile phones.

PubMed

Erdreich, Linda S; Van Kerkhove, Maria D; Scrafford, Carolyn G; Barraj, Leila; McNeely, Mark; Shum, Mona; Sheppard, Asher R; Kelsh, Michael

2007-08-01

Epidemiological studies of mobile phone use and risk of brain cancer have relied on self-reported use, years as a subscriber, and billing records as exposure surrogates without addressing the level of radiofrequency (RF) power output. The objective of this study was to measure environmental, behavioral and engineering factors affecting the RF power output of GSM mobile phones during operation. We estimated the RF-field exposure of volunteer subjects who made mobile phone calls using software-modified phones (SMPs) that recorded output power settings. Subjects recruited from three geographic areas in the U.S. were instructed to log information (place, time, etc.) for each call made and received during a 5-day period. The largest factor affecting energy output was study area, followed by user movement and location (inside or outside), use of a hands-free device, and urbanicity, although the two latter factors accounted for trivial parts of overall variance. Although some highly statistically significant differences were identified, the effects on average energy output rate were usually less than 50% and were generally comparable to the standard deviation. These results provide information applicable to improving the precision of exposure metrics for epidemiological studies of GSM mobile phones and may have broader application for other mobile phone systems and geographic locations.

Clinical usefulness of the clock drawing test applying rasch analysis in predicting of cognitive impairment.

PubMed

Yoo, Doo Han; Lee, Jae Shin

2016-07-01

[Purpose] This study examined the clinical usefulness of the clock drawing test applying Rasch analysis for predicting the level of cognitive impairment. [Subjects and Methods] A total of 187 stroke patients with cognitive impairment were enrolled in this study. The 187 patients were evaluated by the clock drawing test developed through Rasch analysis along with the mini-mental state examination of cognitive evaluation tool. An analysis of the variance was performed to examine the significance of the mini-mental state examination and the clock drawing test according to the general characteristics of the subjects. Receiver operating characteristic analysis was performed to determine the cutoff point for cognitive impairment and to calculate the sensitivity and specificity values. [Results] The results of comparison of the clock drawing test with the mini-mental state showed significant differences in according to gender, age, education, and affected side. A total CDT of 10.5, which was selected as the cutoff point to identify cognitive impairement, showed a sensitivity, specificity, Youden index, positive predictive, and negative predicive values of 86.4%, 91.5%, 0.8, 95%, and 88.2%. [Conclusion] The clock drawing test is believed to be useful in assessments and interventions based on its excellent ability to identify cognitive disorders.

Serum HSP70

PubMed Central

Dutta, Sudhir K.; Girotra, Mohit; Singla, Montish; Dutta, Anand; Stephen, F. Otis; Nair, Padmanabhan P.; Merchant, Nipun B.

2014-01-01

Objectives Heat shock protein 70 (HSP70) is overexpressed in human pancreatic cancer cell lines. To determine if serum HSP70 levels are elevated in patients with pancreatic cancer and can function as a biomarker for early detection of pancreatic cancer. Methods Study subjects were divided into 3 groups: histologically proven pancreatic cancer (PC; n = 23), chronic pancreatitis (CP; n = 12), and matched normal control subjects (C; n = 10). Serum HSP70 levels were determined using a novel immunoelectrophoresis method developed and validated by the authors. Significance of difference between the groups was analyzed with analysis of variance (ANOVA). Receiver operating characteristic (ROC) curve analysis was performed to discriminate patients with pancreatic cancer from normal controls. Results The mean ± SE serum HSP70 levels in the PC, CP, and C groups were 1.68 ± 0.083 ng/mL, 0.40 ± 0.057 ng/mL, and 0.04 ng/mL, respectively. Serum HSP70 levels in the PC group were significantly higher compared with either the CP or C groups (P < 0.01). The sensitivity and specificity of elevated serum HSP70 in the PC group was 74% and 90%, respectively. Conclusions Serum HSP70 levels are significantly increased in patients with pancreatic cancer and may be useful as an additional biomarker for the detection of pancreatic cancer. PMID:22158074

Development of the psychometric property of a Minimum Data-Set-Based Depression Rating Scale for use in long-term care facilities in Taiwan.

PubMed

Hsiao, C Y; Lan, C F; Chang, P L; Li, I C

2015-01-01

Our aim is to develop the psychometric property of the Minimum Data-Set-Based Depression Rating Scale (MDS-DRS) to ensure its use to assess service needs and guide care plans for institutionalized residents. 378 residents were recruited from the Haoran Senior Citizen Home in northern Taiwan. The MDS-DRS and GDS-SF were used to identify observable features of depression symptoms in the elderly residents. A total of 378 residents participated in this study. The receiver operating characteristic (ROC) curve indicated that the MDS-DRS has a 43.3% sensitivity and a 90.6% specificity when screening for depression symptoms. The total variance, explained by the two factors 'sadness' and 'distress,' was 58.1% based on the factor analysis. Reliable assessment tools for nurses are important because they allow the early detection of depression symptoms. The MDS-DRS items perform as well as the GDS-SF items in detecting depression symptoms. Furthermore, the MDS-DRS has the advantage of providing information to staff about care process implementation, which can facilitate the identification of areas that need improvement. Further research is needed to validate the use of the MDS-DRS in long-term care facilities.

Generalized t-statistic for two-group classification.

PubMed

Komori, Osamu; Eguchi, Shinto; Copas, John B

2015-06-01

In the classic discriminant model of two multivariate normal distributions with equal variance matrices, the linear discriminant function is optimal both in terms of the log likelihood ratio and in terms of maximizing the standardized difference (the t-statistic) between the means of the two distributions. In a typical case-control study, normality may be sensible for the control sample but heterogeneity and uncertainty in diagnosis may suggest that a more flexible model is needed for the cases. We generalize the t-statistic approach by finding the linear function which maximizes a standardized difference but with data from one of the groups (the cases) filtered by a possibly nonlinear function U. We study conditions for consistency of the method and find the function U which is optimal in the sense of asymptotic efficiency. Optimality may also extend to other measures of discriminatory efficiency such as the area under the receiver operating characteristic curve. The optimal function U depends on a scalar probability density function which can be estimated non-parametrically using a standard numerical algorithm. A lasso-like version for variable selection is implemented by adding L1-regularization to the generalized t-statistic. Two microarray data sets in the study of asthma and various cancers are used as motivating examples. © 2014, The International Biometric Society.

Fair lineups are better than biased lineups and showups, but not because they increase underlying discriminability.

PubMed

Smith, Andrew M; Wells, Gary L; Lindsay, R C L; Penrod, Steven D

2017-04-01

Receiver Operating Characteristic (ROC) analysis has recently come in vogue for assessing the underlying discriminability and the applied utility of lineup procedures. Two primary assumptions underlie recommendations that ROC analysis be used to assess the applied utility of lineup procedures: (a) ROC analysis of lineups measures underlying discriminability, and (b) the procedure that produces superior underlying discriminability produces superior applied utility. These same assumptions underlie a recently derived diagnostic-feature detection theory, a theory of discriminability, intended to explain recent patterns observed in ROC comparisons of lineups. We demonstrate, however, that these assumptions are incorrect when ROC analysis is applied to lineups. We also demonstrate that a structural phenomenon of lineups, differential filler siphoning, and not the psychological phenomenon of diagnostic-feature detection, explains why lineups are superior to showups and why fair lineups are superior to biased lineups. In the process of our proofs, we show that computational simulations have assumed, unrealistically, that all witnesses share exactly the same decision criteria. When criterial variance is included in computational models, differential filler siphoning emerges. The result proves dissociation between ROC curves and underlying discriminability: Higher ROC curves for lineups than for showups and for fair than for biased lineups despite no increase in underlying discriminability. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Performance of genetic risk factors in prediction of trichloroethylene induced hypersensitivity syndrome.

PubMed

Dai, Yufei; Chen, Ying; Huang, Hanlin; Zhou, Wei; Niu, Yong; Zhang, Mingrong; Bin, Ping; Dong, Haiyan; Jia, Qiang; Huang, Jianxun; Yi, Juan; Liao, Qijun; Li, Haishan; Teng, Yanxia; Zang, Dan; Zhai, Qingfeng; Duan, Huawei; Shen, Juan; He, Jiaxi; Meng, Tao; Sha, Yan; Shen, Meili; Ye, Meng; Jia, Xiaowei; Xiang, Yingping; Huang, Huiping; Wu, Qifeng; Shi, Mingming; Huang, Xianqing; Yang, Huanming; Luo, Longhai; Li, Sai; Li, Lin; Zhao, Jinyang; Li, Laiyu; Wang, Jun; Zheng, Yuxin

2015-07-20

Trichloroethylene induced hypersensitivity syndrome is dose-independent and potentially life threatening disease, which has become one of the serious occupational health issues and requires intensive treatment. To discover the genetic risk factors and evaluate the performance of risk prediction model for the disease, we conducted genomewide association study and replication study with total of 174 cases and 1761 trichloroethylene-tolerant controls. Fifty seven SNPs that exceeded the threshold for genome-wide significance (P < 5 × 10(-8)) were screened to relate with the disease, among which two independent SNPs were identified, that is rs2857281 at MICA (odds ratio, 11.92; P meta = 1.33 × 10(-37)) and rs2523557 between HLA-B and MICA (odds ratio, 7.33; P meta = 8.79 × 10(-35)). The genetic risk score with these two SNPs explains at least 20.9% of the disease variance and up to 32.5-fold variation in inter-individual risk. Combining of two SNPs as predictors for the disease would have accuracy of 80.73%, the area under receiver operator characteristic curves (AUC) scores was 0.82 with sensitivity of 74% and specificity of 85%, which was considered to have excellent discrimination for the disease, and could be considered for translational application for screening employees before exposure.

Development and clinical introduction of automated radiotherapy treatment planning for prostate cancer

NASA Astrophysics Data System (ADS)

Winkel, D.; Bol, G. H.; van Asselen, B.; Hes, J.; Scholten, V.; Kerkmeijer, L. G. W.; Raaymakers, B. W.

2016-12-01

To develop an automated radiotherapy treatment planning and optimization workflow to efficiently create patient specifically optimized clinical grade treatment plans for prostate cancer and to implement it in clinical practice. A two-phased planning and optimization workflow was developed to automatically generate 77Gy 5-field simultaneously integrated boost intensity modulated radiation therapy (SIB-IMRT) plans for prostate cancer treatment. A retrospective planning study (n  =  100) was performed in which automatically and manually generated treatment plans were compared. A clinical pilot (n  =  21) was performed to investigate the usability of our method. Operator time for the planning process was reduced to  <5 min. The retrospective planning study showed that 98 plans met all clinical constraints. Significant improvements were made in the volume receiving 72Gy (V72Gy) for the bladder and rectum and the mean dose of the bladder and the body. A reduced plan variance was observed. During the clinical pilot 20 automatically generated plans met all constraints and 17 plans were selected for treatment. The automated radiotherapy treatment planning and optimization workflow is capable of efficiently generating patient specifically optimized and improved clinical grade plans. It has now been adopted as the current standard workflow in our clinic to generate treatment plans for prostate cancer.

Impact of paracervical block on postabortion pain in patients undergoing abortion under general anesthesia.

PubMed

Lazenby, Gweneth B; Fogelson, Nicholas S; Aeby, Tod

2009-12-01

Paracervical block is used as a way to decrease postoperative pain in patients having abortions under general anesthesia. To date, no studies have evaluated the efficacy of this practice. Patients were recruited from a university-based family planning clinic. Seventy-two patients seeking abortion under general anesthesia were enrolled into the single-blinded study. Thirty-nine patients were randomized to receive a paracervical block, and 33 were randomized to no local anesthesia. The patients completed a demographic survey and visual analog pain scales for pain prior to and at several time points after the procedure. Data regarding the need for additional pain medications postoperatively were recorded. Analysis of variance single factor and two-sample one-sided t test were used in data analysis. Experimental and control groups were similar in all measured demographic characteristics. They were also similar in gestational age, number of laminaria required, preoperative dilation, operative time, estimated blood loss and reported complications. Postoperative pain was not significantly affected by placement of a paracervical block prior to abortion under general anesthesia. The need for postoperative pain medication during recovery was similar between groups. This study does not support the hypothesized benefit of local anesthesia prior to surgical abortion under general anesthesia to reduce postoperative pain.

Obstructive apnea hypopnea index estimation by analysis of nocturnal snoring signals in adults.

PubMed

Ben-Israel, Nir; Tarasiuk, Ariel; Zigel, Yaniv

2012-09-01

To develop a whole-night snore sounds analysis algorithm enabling estimation of obstructive apnea hypopnea index (AHI(EST)) among adult subjects. Snore sounds were recorded using a directional condenser microphone placed 1 m above the bed. Acoustic features exploring intra-(mel- cepstability, pitch density) and inter-(running variance, apnea phase ratio, inter-event silence) snore properties were extracted and integrated to assess AHI(EST). University-affiliated sleep-wake disorder center and biomedical signal processing laboratory. Ninety subjects (age 53 ± 13 years, BMI 31 ± 5 kg/m(2)) referred for polysomnography (PSG) diagnosis of OSA were prospectively and consecutively recruited. The system was trained and tested on 60 subjects. Validation was blindly performed on the additional 30 consecutive subjects. AHI(EST) correlated with AHI (AHI(PSG); r(2) = 0.81, P < 0.001). Area under the receiver operating characteristic curve of 85% and 92% for thresholds of 10 and 20 events/h, respectively, were obtained for OSA detection. Both Altman-Bland analysis and diagnostic agreement criteria revealed 80% and 83% agreements of AHI(EST) with AHI(PSG), respectively. Acoustic analysis based on intra- and inter-snore properties can differentiate subjects according to AHI. An acoustic-based screening system may address the growing needs for reliable OSA screening tool. Further studies are needed to support these findings.

Validation of the sperm class analyser CASA system for sperm counting in a busy diagnostic semen analysis laboratory.

PubMed

Dearing, Chey G; Kilburn, Sally; Lindsay, Kevin S

2014-03-01

Sperm counts have been linked to several fertility outcomes making them an essential parameter of semen analysis. It has become increasingly recognised that Computer-Assisted Semen Analysis (CASA) provides improved precision over manual methods but that systems are seldom validated robustly for use. The objective of this study was to gather the evidence to validate or reject the Sperm Class Analyser (SCA) as a tool for routine sperm counting in a busy laboratory setting. The criteria examined were comparison with the Improved Neubauer and Leja 20-μm chambers, within and between field precision, sperm concentration linearity from a stock diluted in semen and media, accuracy against internal and external quality material, assessment of uneven flow effects and a receiver operating characteristic (ROC) analysis to predict fertility in comparison with the Neubauer method. This work demonstrates that SCA CASA technology is not a standalone 'black box', but rather a tool for well-trained staff that allows rapid, high-number sperm counting providing errors are identified and corrected. The system will produce accurate, linear, precise results, with less analytical variance than manual methods that correlate well against the Improved Neubauer chamber. The system provides superior predictive potential for diagnosing fertility problems.

Horizontal Line-of-Sight Turbulence Over Near-Ground Paths and Implications for Adaptive Optics Corrections in Laser Communications.

PubMed

Levine, B M; Martinsen, E A; Wirth, A; Jankevics, A; Toledo-Quinones, M; Landers, F; Bruno, T L

1998-07-20

Atmospheric turbulence over long horizontal paths perturbs phase and can also cause severe intensity scintillation in the pupil of an optical communications receiver, which limits the data rate over which intensity-based modulation schemes can operate. The feasibility of using low-order adaptive optics by applying phase-only corrections over horizontal propagation paths is investigated. A Shack-Hartmann wave-front sensor was built and data were gathered on paths 1 m above ground and between a 1- and 2.5-km range. Both intensity fluctuations and optical path fluctuation statistics were gathered within a single frame, and the wave-front reconstructor was modified to allow for scintillated data. The temporal power spectral density for various Zernike polynomial modes was used to determine the effects of the expected corrections by adaptive optics. The slopes of the inertial subrange of turbulence were found to be less than predicted by Kolmogorov theory with an infinite outer scale, and the distribution of variance explained by increasing order was also found to be different. Statistical analysis of these data in the 1-km range indicates that at communications wavelengths of 1.3 mum, a significant improvement in transmitted beam quality could be expected most of the time, to a performance of 10% Strehl ratio or better.

A Quasi-Universal Nonword Repetition Task as a Diagnostic Tool for Bilingual Children Learning Dutch as a Second Language.

PubMed

Boerma, Tessel; Chiat, Shula; Leseman, Paul; Timmermeister, Mona; Wijnen, Frank; Blom, Elma

2015-12-01

This study evaluated a newly developed quasi-universal nonword repetition task (Q-U NWRT) as a diagnostic tool for bilingual children with language impairment (LI) who have Dutch as a 2nd language. The Q-U NWRT was designed to be minimally influenced by knowledge of 1 specific language in contrast to a language-specific NWRT with which it was compared. One hundred twenty monolingual and bilingual children with and without LI participated (30 per group). A mixed-design analysis of variance was used to investigate the effects of LI and bilingualism on the NWRTs. Receiver operating characteristic analyses were conducted to evaluate the instruments' diagnostic value. Large negative effects of LI were found on both NWRTs, whereas negative effects of bilingualism only occurred on the language-specific NWRT. Both instruments had high clinical accuracy in the monolingual group, but only the Q-U NWRT had high clinical accuracy in the bilingual group. This study indicates that the Q-U NWRT is a promising diagnostic tool to help identify LI in bilingual children learning Dutch as a 2nd language. The instrument was clinically accurate in both a monolingual and bilingual group of children and seems better able to disentangle LI from language disadvantage than more language-specific measures.

Father Attendance in Nurse Home Visitation

PubMed Central

Holmberg, John R.; Olds, David L.

2015-01-01

Our aim was to examine the rates and predictors of father attendance at nurse home visits in replication sites of the Nurse-Family Partnership (NFP). Early childhood programs can facilitate father involvement in the lives of their children, but program improvements require an understanding of factors that predict father involvement. The sample consisted of 29,109 low-income, first-time mothers who received services from 694 nurses from 80 sites. We conducted mixed-model multiple regression analyses to identify population, implementation, site, and nurse influences on father attendance. Predictors of father attendance included a count of maternal visits (B = 0.12, SE = 0.01, F = 3101.77), frequent contact between parents (B = 0.61, SE = 0.02, F = 708.02), cohabitation (B = 1.41, SE = 0.07, F = 631.51), White maternal race (B = 0.77, SE = 0.06, F = 190.12), and marriage (B = 0.42, SE = 0.08, F = 30.08). Random effects for sites and nurses predicted father-visit participation (2.7 & 6.7% of the variance, respectively), even after controlling for population sociodemographic characteristics. These findings suggest that factors operating at the levels of sites and nurses influence father attendance at home visits, even after controlling for differences in populations served. Further inquiry about these influences on father visit attendance is likely to inform program-improvement efforts. PMID:25521707

Lung injury induced by secondhand smoke exposure detected with hyperpolarized helium-3 diffusion MR.

PubMed

Wang, Chengbo; Mugler, John P; de Lange, Eduard E; Patrie, James T; Mata, Jaime F; Altes, Talissa A

2014-01-01

To determine whether helium-3 diffusion MR can detect the changes in the lungs of healthy nonsmoking individuals who were regularly exposed to secondhand smoke. Three groups were studied (age: 59 ± 9 years): 23 smokers, 37 exposure-to-secondhand-smoke subjects, and 29 control subjects. We measured helium-3 diffusion values at diffusion times from 0.23 to 1.97 s. One-way analysis of variance revealed that the mean area under the helium-3 diffusion curves (ADC AUC) of the smokers was significantly elevated compared with the controls and to the exposure-to-secondhand-smoke subjects (P < 0.001 both). No difference between the mean ADC AUC of the exposure-to-secondhand-smoke subjects and that of the controls was found (P = 0.115). However, application of a receiver operator characteristic-derived rule to classify subjects as either a "control" or a "smoker," based on ADC AUC, revealed that 30% (11/37) of the exposure-to-secondhand subjects were classified as "smokers" indicating an elevation of the ADC AUC. Using helium-3 diffusion MR, elevated ADC values were detected in 30% of nonsmoking healthy subjects who had been regularly exposed to secondhand smoke, supporting the concept that, in susceptible individuals, secondhand smoke causes mild lung damage. Copyright © 2013 Wiley Periodicals, Inc.

Statistical methodology for estimating the mean difference in a meta-analysis without study-specific variance information.

PubMed

Sangnawakij, Patarawan; Böhning, Dankmar; Adams, Stephen; Stanton, Michael; Holling, Heinz

2017-04-30

Statistical inference for analyzing the results from several independent studies on the same quantity of interest has been investigated frequently in recent decades. Typically, any meta-analytic inference requires that the quantity of interest is available from each study together with an estimate of its variability. The current work is motivated by a meta-analysis on comparing two treatments (thoracoscopic and open) of congenital lung malformations in young children. Quantities of interest include continuous end-points such as length of operation or number of chest tube days. As studies only report mean values (and no standard errors or confidence intervals), the question arises how meta-analytic inference can be developed. We suggest two methods to estimate study-specific variances in such a meta-analysis, where only sample means and sample sizes are available in the treatment arms. A general likelihood ratio test is derived for testing equality of variances in two groups. By means of simulation studies, the bias and estimated standard error of the overall mean difference from both methodologies are evaluated and compared with two existing approaches: complete study analysis only and partial variance information. The performance of the test is evaluated in terms of type I error. Additionally, we illustrate these methods in the meta-analysis on comparing thoracoscopic and open surgery for congenital lung malformations and in a meta-analysis on the change in renal function after kidney donation. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Fat-free mass is not lower 24 months postbariatric surgery than nonoperated matched controls

PubMed Central

Strain, Gladys Witt; Ebel, Faith; Honohan, Jamie; Gagner, Michel; Dakin, Gregory F.; Pomp, Alfons; Gallagher, Dympna

2017-01-01

Objective Concerns about an excessive loss of fat-free mass (FFM) after bariatric surgery prompted this comparison of operated versus matched nonoperated controls regarding FFM. Setting University Hospital and University Research Unit in an urban medical center. Methods Body composition with bioelectric impedance (Tanita 310, Tanita Corp, Arlington Heights, IL) was measured approximately 2 years after bariatric surgery in weight stable patients and nonoperated weight stable controls matched for body mass index (BMI), gender, and age. t tests provided comparisons. Analysis of variance was used to compare FFM changes for 4 procedures. Levene’s test evaluated variance. Results Patients (n = 252; 24.7 ± 15 mo after surgery) and nonoperated controls (n = 252) were matched for gender (71.8% female), age (44.5 ± 11.0 yr), and BMI (32.8 ± 7.0 kg/m2). Patients had different surgical procedures: 107 gastric bypasses (RYGBs), 62 biliopancreatic diversions with duodenal switch (BPD/DSs), 40 adjustable gastric bands (AGBs), and 43 sleeve gastrectomies (LSGs). FFM percentage was significantly higher in the operated patients than controls, 66% versus 62%, P < .0001. For 3 procedures, the FFM was significantly higher; however, AGBs changed only 7.3 BMI units and FFM was not significantly different from their matched controls, 59.8% versus 58.2%. Across surgical groups, FFM percentage differed, P < .0001 (RYGB 66.5 ± 9.2%, BPD/DS 74.0 ± 9.3%, AGB 59.8 ± 7.0%, LSG 59.6 ± 9.3%). Variance was not different (P = .17). Conclusion Weight-reduced bariatric surgery patients have greater FFM compared with nonoperated matched controls. These findings support surgically assisted weight loss as a physiologic process and in general patients do not suffer from excessive FFM depletion after bariatric procedures. PMID:27387700

Defining the Costs of Reusable Flexible Ureteroscope Reprocessing Using Time-Driven Activity-Based Costing.

PubMed

Isaacson, Dylan; Ahmad, Tessnim; Metzler, Ian; Tzou, David T; Taguchi, Kazumi; Usawachintachit, Manint; Zetumer, Samuel; Sherer, Benjamin; Stoller, Marshall; Chi, Thomas

2017-10-01

Careful decontamination and sterilization of reusable flexible ureteroscopes used in ureterorenoscopy cases prevent the spread of infectious pathogens to patients and technicians. However, inefficient reprocessing and unavailability of ureteroscopes sent out for repair can contribute to expensive operating room (OR) delays. Time-driven activity-based costing (TDABC) was applied to describe the time and costs involved in reprocessing. Direct observation and timing were performed for all steps in reprocessing of reusable flexible ureteroscopes following operative procedures. Estimated times needed for each step by which damaged ureteroscopes identified during reprocessing are sent for repair were characterized through interviews with purchasing analyst staff. Process maps were created for reprocessing and repair detailing individual step times and their variances. Cost data for labor and disposables used were applied to calculate per minute and average step costs. Ten ureteroscopes were followed through reprocessing. Process mapping for ureteroscope reprocessing averaged 229.0 ± 74.4 minutes, whereas sending a ureteroscope for repair required an estimated 143 minutes per repair. Most steps demonstrated low variance between timed observations. Ureteroscope drying was the longest and highest variance step at 126.5 ± 55.7 minutes and was highly dependent on manual air flushing through the ureteroscope working channel and ureteroscope positioning in the drying cabinet. Total costs for reprocessing totaled $96.13 per episode, including the cost of labor and disposable items. Utilizing TDABC delineates the full spectrum of costs associated with ureteroscope reprocessing and identifies areas for process improvement to drive value-based care. At our institution, ureteroscope drying was one clearly identified target area. Implementing training in ureteroscope drying technique could save up to 2 hours per reprocessing event, potentially preventing expensive OR delays.

Relative Impact of Surgeon and Hospital Volume on Operative Mortality and Complications Following Pancreatic Resection in Medicare Patients

PubMed Central

Mehta, Hemalkumar B.; Parmar, Abhishek D.; Adhikari, Deepak; Tamirisa, Nina P.; Dimou, Francesca; Jupiter, Daniel; Riall, Taylor S.

2016-01-01

Background Surgeon and hospital volume are both known to affect outcomes for patients undergoing pancreatic resection. The objective was to evaluate the relative effects of surgeon and hospital volume on 30-day mortality and 30-day complications after pancreatic resection among older patients. Materials and Methods The study used Texas Medicare data (2000–2012), identifying high-volume surgeons as those performing ≥4 pancreatic resections/year, and high-volume hospitals as those performing ≥11 pancreatic resections/year, on Medicare patients. Three-level hierarchical logistic regression models were used to evaluate the relative effects of surgeon and hospital volumes on mortality and complications, after adjusting for case mix differences. Results There were 2,453 pancreatic resections performed by 490 surgeons operating in 138 hospitals. 4.5% of surgeons and 6.5% of hospitals were high-volume. The overall 30-day mortality was 9.0%, and the 30-day complication rate was 40.6%. Overall, 8.9% of the variance in 30-day mortality was attributed to surgeon factors and 9.8% to hospital factors. For 30-day complications, 4.7% of the variance was attributed to surgeon factors and 1.2% to hospital factors. After adjusting for patient, surgeon and hospital characteristics, high surgeon volume (OR 0.54, 95% CI 0.33–0.87) and high hospital volume (OR, 0.52; 95% CI, 0.30–0.92) were associated with lower risk of mortality; high surgeon volume (OR 0.71, 95% CI 0.55–0.93) was also associated lower risk of 30-day complications. Conclusions Both hospital and surgeon factors contributed significantly to the observed variance in mortality, but only surgeon factors impacted complications. PMID:27565068

Intercomparison of AIRS and HIRDLS stratospheric gravity wave observations

NASA Astrophysics Data System (ADS)

Meyer, Catrin I.; Ern, Manfred; Hoffmann, Lars; Trinh, Quang Thai; Alexander, M. Joan

2018-01-01

We investigate stratospheric gravity wave observations by the Atmospheric InfraRed Sounder (AIRS) aboard NASA's Aqua satellite and the High Resolution Dynamics Limb Sounder (HIRDLS) aboard NASA's Aura satellite. AIRS operational temperature retrievals are typically not used for studies of gravity waves, because their vertical and horizontal resolution is rather limited. This study uses data of a high-resolution retrieval which provides stratospheric temperature profiles for each individual satellite footprint. Therefore the horizontal sampling of the high-resolution retrieval is 9 times better than that of the operational retrieval. HIRDLS provides 2-D spectral information of observed gravity waves in terms of along-track and vertical wavelengths. AIRS as a nadir sounder is more sensitive to short-horizontal-wavelength gravity waves, and HIRDLS as a limb sounder is more sensitive to short-vertical-wavelength gravity waves. Therefore HIRDLS is ideally suited to complement AIRS observations. A calculated momentum flux factor indicates that the waves seen by AIRS contribute significantly to momentum flux, even if the AIRS temperature variance may be small compared to HIRDLS. The stratospheric wave structures observed by AIRS and HIRDLS often agree very well. Case studies of a mountain wave event and a non-orographic wave event demonstrate that the observed phase structures of AIRS and HIRDLS are also similar. AIRS has a coarser vertical resolution, which results in an attenuation of the amplitude and coarser vertical wavelengths than for HIRDLS. However, AIRS has a much higher horizontal resolution, and the propagation direction of the waves can be clearly identified in geographical maps. The horizontal orientation of the phase fronts can be deduced from AIRS 3-D temperature fields. This is a restricting factor for gravity wave analyses of limb measurements. Additionally, temperature variances with respect to stratospheric gravity wave activity are compared on a statistical basis. The complete HIRDLS measurement period from January 2005 to March 2008 is covered. The seasonal and latitudinal distributions of gravity wave activity as observed by AIRS and HIRDLS agree well. A strong annual cycle at mid- and high latitudes is found in time series of gravity wave variances at 42 km, which has its maxima during wintertime and its minima during summertime. The variability is largest during austral wintertime at 60° S. Variations in the zonal winds at 2.5 hPa are associated with large variability in gravity wave variances. Altogether, gravity wave variances of AIRS and HIRDLS are complementary to each other. Large parts of the gravity wave spectrum are covered by joint observations. This opens up fascinating vistas for future gravity wave research.

A versatile microprocessor-controlled hybrid receiver. [with firmware control for operation over large frequency uncertainty

NASA Technical Reports Server (NTRS)

Grant, T. L.

1978-01-01

A hybrid receiver has been designed for the Galileo Project. The receiver, located on the Galileo Orbiter, will autonomously acquire and track signals from the first atmospheric probe of Jupiter as well as demodulate, bit-synchronize, and buffer the telemetry data. The receiver has a conventional RF and LF front end but performs multiple functions digitally under firmware control. It will be a self-acquiring receiver that operates under a large frequency uncertainty; it can accommodate different modulation types, bit rates, and other parameter changes via reprogramming. A breadboard receiver and test set demonstrate a preliminary version of the sequential detection process and verify the hypothesis that a fading channel does not reduce the probability of detection.

Artificial neural network approach to predict surgical site infection after free-flap reconstruction in patients receiving surgery for head and neck cancer.

PubMed

Kuo, Pao-Jen; Wu, Shao-Chun; Chien, Peng-Chen; Chang, Shu-Shya; Rau, Cheng-Shyuan; Tai, Hsueh-Ling; Peng, Shu-Hui; Lin, Yi-Chun; Chen, Yi-Chun; Hsieh, Hsiao-Yun; Hsieh, Ching-Hua

2018-03-02

The aim of this study was to develop an effective surgical site infection (SSI) prediction model in patients receiving free-flap reconstruction after surgery for head and neck cancer using artificial neural network (ANN), and to compare its predictive power with that of conventional logistic regression (LR). There were 1,836 patients with 1,854 free-flap reconstructions and 438 postoperative SSIs in the dataset for analysis. They were randomly assigned tin ratio of 7:3 into a training set and a test set. Based on comprehensive characteristics of patients and diseases in the absence or presence of operative data, prediction of SSI was performed at two time points (pre-operatively and post-operatively) with a feed-forward ANN and the LR models. In addition to the calculated accuracy, sensitivity, and specificity, the predictive performance of ANN and LR were assessed based on area under the curve (AUC) measures of receiver operator characteristic curves and Brier score. ANN had a significantly higher AUC (0.892) of post-operative prediction and AUC (0.808) of pre-operative prediction than LR (both P <0.0001). In addition, there was significant higher AUC of post-operative prediction than pre-operative prediction by ANN (p<0.0001). With the highest AUC and the lowest Brier score (0.090), the post-operative prediction by ANN had the highest overall predictive performance. The post-operative prediction by ANN had the highest overall performance in predicting SSI after free-flap reconstruction in patients receiving surgery for head and neck cancer.

Minimum-variance Brownian motion control of an optically trapped probe.

PubMed

Huang, Yanan; Zhang, Zhipeng; Menq, Chia-Hsiang

2009-10-20

This paper presents a theoretical and experimental investigation of the Brownian motion control of an optically trapped probe. The Langevin equation is employed to describe the motion of the probe experiencing random thermal force and optical trapping force. Since active feedback control is applied to suppress the probe's Brownian motion, actuator dynamics and measurement delay are included in the equation. The equation of motion is simplified to a first-order linear differential equation and transformed to a discrete model for the purpose of controller design and data analysis. The derived model is experimentally verified by comparing the model prediction to the measured response of a 1.87 microm trapped probe subject to proportional control. It is then employed to design the optimal controller that minimizes the variance of the probe's Brownian motion. Theoretical analysis is derived to evaluate the control performance of a specific optical trap. Both experiment and simulation are used to validate the design as well as theoretical analysis, and to illustrate the performance envelope of the active control. Moreover, adaptive minimum variance control is implemented to maintain the optimal performance in the case in which the system is time varying when operating the actively controlled optical trap in a complex environment.

Noise induced hearing loss of forest workers in Turkey.

PubMed

Tunay, M; Melemez, K

2008-09-01

In this study, a total number of 114 workers who were in 3 different groups in terms of age and work underwent audiometric analysis. In order to determine whether there was a statistically significant difference between the hearing loss levels of the workers who were included in the study, variance analysis was applied with the help of the data obtained as a result of the evaluation. Correlation and regression analysis were applied in order to determine the relations between hearing loss and their age and their time of work. As a result of the variance analysis, statistically significant differences were found at 500, 2000 and 4000 Hz frequencies. The most specific difference was observed among chainsaw machine operators at 4000 Hz frequency, which was determined by the variance analysis. As a result of the correlation analysis, significant relations were found between time of work and hearing loss in 0.01 confidence level and between age and hearing loss in 0.05 confidence level. Forest workers using chainsaw machines should be informed, they should wear or use protective materials and less noising chainsaw machines should be used if possible and workers should undergo audiometric tests when they start work and once a year.

Dehydroepiandrosterone and dehydroepiandrosterone sulfate: anabolic, neuroprotective, and neuroexcitatory properties in military men.

PubMed

Taylor, Marcus K

2013-01-01

Evidence links dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) to crucial military health issues, including operational stress, resilience, and traumatic brain injury. This study evaluated the anabolic, neuroprotective, and neuroexcitatory properties of DHEA(S) in healthy military men. A salivary sample was obtained from 42 men and assayed for DHEA(S), testosterone, nerve growth factor (NGF; which supports nerve cell proliferation), and salivary alpha amylase (sAA; a proxy of sympathetic nervous system function). Separate regression analyses were conducted with DHEA and DHEAS as independent variables, and testosterone, NGF, and sAA as dependent variables, respectively. The models explained 23.4% of variance in testosterone (p < 0.01), 17.2% of variance in NGF (p < 0.01), and 7.4% of variance in sAA (p = 0.09). Standardized beta coefficients revealed that DHEA independently influenced testosterone (beta = 0.40, p < 0.01), whereas DHEAS independently influenced NGF (beta = 0.48, p < 0.01) and sAA (beta = 0.36, p < 0.05). DHEA demonstrated anabolic properties, whereas DHEAS demonstrated neuroprotective and neuroexcitatory properties in military men. This area of study has broad implications for stress inoculation, traumatic brain injury rehabilitation, and regenerative medicine in military personnel.

Aircrew coordination and decisionmaking: Peer ratings of video tapes made during a full mission simulation

NASA Technical Reports Server (NTRS)

Murphy, M. R.; Awe, C. A.

1986-01-01

Six professionally active, retired captains rated the coordination and decisionmaking performances of sixteen aircrews while viewing videotapes of a simulated commercial air transport operation. The scenario featured a required diversion and a probable minimum fuel situation. Seven point Likert-type scales were used in rating variables on the basis of a model of crew coordination and decisionmaking. The variables were based on concepts of, for example, decision difficulty, efficiency, and outcome quality; and leader-subordin ate concepts such as person and task-oriented leader behavior, and competency motivation of subordinate crewmembers. Five-front-end variables of the model were in turn dependent variables for a hierarchical regression procedure. The variance in safety performance was explained 46%, by decision efficiency, command reversal, and decision quality. The variance of decision quality, an alternative substantive dependent variable to safety performance, was explained 60% by decision efficiency and the captain's quality of within-crew communications. The variance of decision efficiency, crew coordination, and command reversal were in turn explained 78%, 80%, and 60% by small numbers of preceding independent variables. A principle component, varimax factor analysis supported the model structure suggested by regression analyses.

Cost effective stream-gaging strategies for the Lower Colorado River basin; the Blythe field office operations

USGS Publications Warehouse

Moss, Marshall E.; Gilroy, Edward J.

1980-01-01

This report describes the theoretical developments and illustrates the applications of techniques that recently have been assembled to analyze the cost-effectiveness of federally funded stream-gaging activities in support of the Colorado River compact and subsequent adjudications. The cost effectiveness of 19 stream gages in terms of minimizing the sum of the variances of the errors of estimation of annual mean discharge is explored by means of a sequential-search optimization scheme. The search is conducted over a set of decision variables that describes the number of times that each gaging route is traveled in a year. A gage route is defined as the most expeditious circuit that is made from a field office to visit one or more stream gages and return to the office. The error variance is defined as a function of the frequency of visits to a gage by using optimal estimation theory. Currently a minimum of 12 visits per year is made to any gage. By changing to a six-visit minimum, the same total error variance can be attained for the 19 stations with a budget of 10% less than the current one. Other strategies are also explored. (USGS)

Receiver System: Lessons Learned from Solar Two

NASA Astrophysics Data System (ADS)

Litwin, R. Z.

2002-03-01

The Boeing Company fabricated the Solar Two receiver as a subcontractor for the Solar Two project. The receiver absorbed sunlight reflected from the heliostat field. A molten-nitrate-salt heat transfer fluid was pumped from a storage tank at grade level, heated from 290 to 565DGC by the receiver mounted on top of a tower, then flowed back down into another storage tank. To make electricity, the hot salt was pumped through a steam generator to produce steam that powered a conventional Rankine steam turbine/generator. This evaluation identifies the most significant Solar Two receiver system lessons learned from the Mechanical Design, Instrumentation and Control, Panel Fabrication, Site Construction, Receiver System Operation, and Management from the perspective of the receiver designer/manufacturer. The lessons learned on the receiver system described here consist of two parts: the Problem and one or more identified Solutions. The appendix summarizes an inspection of the advanced receiver panel developed by Boeing that was installed and operated in the Solar Two receiver.

Receiver System: Lessons Learned From Solar Two

DOE Office of Scientific and Technical Information (OSTI.GOV)

LITWIN, ROBERT Z.; PACHECO, JAMES E.

The Boeing Company fabricated the Solar Two receiver as a subcontractor for the Solar Two project. The receiver absorbed sunlight reflected from the heliostat field. A molten-nitrate-salt heat transfer fluid was pumped from a storage tank at grade level, heated from 290 to 565 C by the receiver mounted on top of a tower, then flowed back down into another storage tank. To make electricity, the hot salt was pumped through a steam generator to produce steam that powered a conventional Rankine steam turbine/generator. This evaluation identifies the most significant Solar Two receiver system lessons learned from the Mechanical Design,more » Instrumentation and Control, Panel Fabrication, Site Construction, Receiver System Operation, and Management from the perspective of the receiver designer/manufacturer. The lessons learned on the receiver system described here consist of two parts: the Problem and one or more identified Solutions. The appendix summarizes an inspection of the advanced receiver panel developed by Boeing that was installed and operated in the Solar Two receiver.« less

Quantifying the tracking capability of space-based AIS systems

NASA Astrophysics Data System (ADS)

Skauen, Andreas Nordmo

2016-01-01

The Norwegian Defence Research Establishment (FFI) has operated three Automatic Identification System (AIS) receivers in space. Two are on dedicated nano-satellites, AISSat-1 and AISSat-2. The third, the NORAIS Receiver, was installed on the International Space Station. A general method for calculating the upper bound on the tracking capability of a space-based AIS system has been developed and the results from the algorithm applied to AISSat-1 and the NORAIS Receiver individually. In addition, a constellation of AISSat-1 and AISSat-2 is presented. The tracking capability is defined as the probability of re-detecting ships as they move around the globe and is explained to represent and upper bound on a space-based AIS system performance. AISSat-1 and AISSat-2 operates on the nominal AIS1 and AIS2 channels, while the NORAIS Receiver data used are from operations on the dedicated space AIS channels, AIS3 and AIS4. The improved tracking capability of operations on the space AIS channels is presented.

Dynamic detailed model of a molten salt tower receiver, with ThermoSysPro library: Impacts of several failures or operational transients on the receiver dynamic behavior

NASA Astrophysics Data System (ADS)

Hefni, Baligh El; Bourdil, Charles

2017-06-01

Molten salt technology represents nowadays the most cost-effective technology for electricity generation for solar power plant. The molten salt tower receiver is based on a field of individually sun-tracking mirrors (heliostats) that reflect the incident sunshine to a receiver at the top of a centrally located tower. The objective of this study is to assess the impact of several transients issued from different scenarios (failure or normal operation mode) on the receiver dynamic behavior. A dynamic detailed model of Solar Two molten salt central receiver has been developed. The component model is meant to be used for receiver modeling with the ThermoSysPro library, developed by EDF. The paper also gives the results of the dynamic simulation for the selected scenarios on Solar Two receiver.

Effects of Small-Group Tutoring with and without Validated Classroom Instruction on At-Risk Students' Math Problem Solving: Are Two Tiers of Prevention Better Than One?

PubMed

Fuchs, Lynn S; Fuchs, Douglas; Craddock, Caitlin; Hollenbeck, Kurstin N; Hamlett, Carol L; Schatschneider, Christopher

2008-01-01

The purpose of this study was to assess the effects of small-group tutoring with and without validated classroom instruction on at-risk (AR) students' math problem solving. Stratifying within schools, 119 3(rd)-grade classes were randomly assigned to conventional or validated problem-solving instruction (Hot Math [schema-broadening instruction]). Students identified as AR (n = 243) were randomly assigned, within classroom conditions, to receive Hot Math tutoring or not. Students were tested on problem-solving and math applications measures before and after 16 weeks of intervention. Analyses of variance, which accounted for the nested structure of the data, revealed the tutored students who received validated classroom instruction achieved better than tutored students who received conventional classroom instruction (ES = 1.34). However, the advantage for tutoring over no tutoring was similar whether or not students received validated or conventional classroom instruction (ESs = 1.18 and 1.13). Tutoring, not validated classroom instruction reduced the prevalence of math difficulty. Implications for responsiveness-to-intervention prevention models and for enhancing math problem-solving instruction are discussed.

Effects of Small-Group Tutoring with and without Validated Classroom Instruction on At-Risk Students' Math Problem Solving: Are Two Tiers of Prevention Better Than One?

PubMed Central

Fuchs, Lynn S.; Fuchs, Douglas; Craddock, Caitlin; Hollenbeck, Kurstin N.; Hamlett, Carol L.; Schatschneider, Christopher

2008-01-01

The purpose of this study was to assess the effects of small-group tutoring with and without validated classroom instruction on at-risk (AR) students' math problem solving. Stratifying within schools, 119 3rd-grade classes were randomly assigned to conventional or validated problem-solving instruction (Hot Math [schema-broadening instruction]). Students identified as AR (n = 243) were randomly assigned, within classroom conditions, to receive Hot Math tutoring or not. Students were tested on problem-solving and math applications measures before and after 16 weeks of intervention. Analyses of variance, which accounted for the nested structure of the data, revealed the tutored students who received validated classroom instruction achieved better than tutored students who received conventional classroom instruction (ES = 1.34). However, the advantage for tutoring over no tutoring was similar whether or not students received validated or conventional classroom instruction (ESs = 1.18 and 1.13). Tutoring, not validated classroom instruction reduced the prevalence of math difficulty. Implications for responsiveness-to-intervention prevention models and for enhancing math problem-solving instruction are discussed. PMID:19122881

Reconfigurable Auditory-Visual Display

NASA Technical Reports Server (NTRS)

Begault, Durand R. (Inventor); Anderson, Mark R. (Inventor); McClain, Bryan (Inventor); Miller, Joel D. (Inventor)

2008-01-01

System and method for visual and audible communication between a central operator and N mobile communicators (N greater than or equal to 2), including an operator transceiver and interface, configured to receive and display, for the operator, visually perceptible and audibly perceptible signals from each of the mobile communicators. The interface (1) presents an audible signal from each communicator as if the audible signal is received from a different location relative to the operator and (2) allows the operator to select, to assign priority to, and to display, the visual signals and the audible signals received from a specified communicator. Each communicator has an associated signal transmitter that is configured to transmit at least one of the visual signals and the audio signal associated with the communicator, where at least one of the signal transmitters includes at least one sensor that senses and transmits a sensor value representing a selected environmental or physiological parameter associated with the communicator.

A class of optimum digital phase locked loops for the DSN advanced receiver

NASA Technical Reports Server (NTRS)

Hurd, W. J.; Kumar, R.

1985-01-01

A class of optimum digital filters for digital phase locked loop of the deep space network advanced receiver is discussed. The filter minimizes a weighted combination of the variance of the random component of the phase error and the sum square of the deterministic dynamic component of phase error at the output of the numerically controlled oscillator (NCO). By varying the weighting coefficient over a suitable range of values, a wide set of filters are obtained such that, for any specified value of the equivalent loop-noise bandwidth, there corresponds a unique filter in this class. This filter thus has the property of having the best transient response over all possible filters of the same bandwidth and type. The optimum filters are also evaluated in terms of their gain margin for stability and their steady-state error performance.

Measuring what matters: Effectively predicting language and literacy in children with cochlear implants

PubMed Central

Nittrouer, Susan; Caldwell, Amanda; Holloman, Christopher

2012-01-01

Objective To evaluate how well various language measures typically used with very young children after they receive cochlear implants predict language and literacy skills as they enter school. Methods Subjects were 50 children who had just completed kindergarten and were 6 or 7 years of age. All had previously participated in a longitudinal study from 12 to 48 months of age. 27 children had severe-to-profound hearing loss and wore cochlear implants, 8 had moderate hearing loss and wore hearing aids, and 15 had normal hearing. A latent variable of language/literacy skill was constructed from scores on six kinds of measures: (1) language comprehension; (2) expressive vocabulary; (3) phonological awareness; (4) literacy; (5) narrative skill; and (6) processing speed. Five kinds of language measures obtained at six-month intervals from 12 to 48 months of age were used as predictor variables in correlational analyses: (1) language comprehension; (2) expressive vocabulary; (3) syntactic structure of productive speech; (4) form and (5) function of language used in language samples. Results Outcomes quantified how much variance in kindergarten language/literacy performance was explained by each predictor variable, at each earlier age of testing. Comprehension measures consistently predicted roughly 25 to 50 percent of the variance in kindergarten language/literacy performance, and were the only effective predictors before 24 months of age. Vocabulary and syntactic complexity were strong predictors after roughly 36 months of age. Amount of speech produced in language samples and number of answers to parental queries explained moderate amounts of variance in performance after 24 months of age. Number of manual gestures and nonspeech vocalizations produced in language samples explained little to no variance before 24 months of age, and after that were negatively correlated with kindergarten performance. The number of imitations produced in language samples at 24 months of age explained about 10 percent of variance in kindergarten performance, but was otherwise not correlated or negatively correlated with kindergarten outcomes. Conclusions Before 24 months of age, the best predictor of later language success is language comprehension. In general, measures that index a child’s cognitive processing of language are the most sensitive predictors of school-age language abilities. PMID:22648088

Advanced development receiver thermal vacuum tests with cold wall

NASA Technical Reports Server (NTRS)

Sedgwick, Leigh M.

1991-01-01

The first ever testing of a full size solar dynamic heat receiver using high temperature thermal energy storage was completed. The heat receiver was designed to meet the requirements for operation on the Space Station Freedom. The purpose of the test program was to quantify the receiver thermodynamic performance, its operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber with liquid nitrogen cold shrouds and an aperture cold plate to partially simulate a low Earth orbit environment. The cavity of the receiver was heated by an infrared quartz lamp heater with 30 independently controllable zones to produce flux distributions typical of candidate concentrators. A closed Brayton cycle engine simulator conditioned a helium xenon gas mixture to specific interface conditions to simulate various operational modes of the solar dynamic power module. Inlet gas temperature, pressure, and flow rate were independently varied. A total of 58 simulated orbital cycles were completed during the test conduct period. The test hardware, execution of testing, test data, and post test inspections are described.

Wideband fixed-tuned SIS receiver for 200-GHz operation

NASA Technical Reports Server (NTRS)

Blundell, Raymond; Tong, Cheuk-Yu E.; Papa, D. Cosmo; Leombruno, R. Louie; Zhang, Xiaolei; Paine, Scott; Stern, Jeffrey A.; Leduc, Henry G.; Bumble, Bruce

1995-01-01

We report on the design and development of a heterodyne receiver, designed to cover the frequency range 176-256 GHz. This receiver incorporates a niobium superconductor-insulator-superconductor (SIS) tunnel junction mixer, which, chiefly for reasons of reliability and ease of operation, is a fixed-tuned waveguide design. On-chip tuning is provided to resonate out the junction's geometric capacitance and produce a good match to the waveguide circuit. Laboratory measurements on the first test receiver indicate that the required input bandwidth (about 40%) is achieved with an average receiver noise temperature of below 50 K. Mixer conversion gain is observed at some frequencies, and the lowest measured receiver noise is less than 30 K. Furthermore, the SIS mixer used in this receiver is of simple construction, is easy to assemble and is therefore a good candidate for duplication.

Dual-Polarization, Sideband-Separating, Balanced Receiver for 1.5 THz

NASA Technical Reports Server (NTRS)

Chattopadhyay, Goutman; Ward, John; Manohara, Harish; Siegel, Peter

2009-01-01

A proposed heterodyne receiver would be capable of detecting electromagnetic radiation in both of two orthogonal linear polarizations, separating sidebands, and providing balanced outputs in a frequency band centered at 1.5 THz with a fractional bandwidth greater than 40 percent. Dual polarization, sideband-separating, and balanced-output receivers are well-known and have been used extensively at frequencies up to about 100 GHz; and there was an earlier proposal for such a receiver for frequencies up to 900 GHz. However, the present proposal represents the first realistic design concept for such a receiver capable of operating above 1 THz. The proposed receiver is intended to be a prototype of mass-producible receiver units, operating at frequencies up to 6 THz, that would be incorporated into highly sensitive heterodyne array instruments to be used in astronomical spectroscopic and imaging studies.

Transition of Attention in Terminal Area NextGen Operations Using Synthetic Vision Systems

NASA Technical Reports Server (NTRS)

Ellis, Kyle K. E.; Kramer, Lynda J.; Shelton, Kevin J.; Arthur, Shelton, J. J., III; Prinzel, Lance J., III; Norman, Robert M.

2011-01-01

This experiment investigates the capability of Synthetic Vision Systems (SVS) to provide significant situation awareness in terminal area operations, specifically in low visibility conditions. The use of a Head-Up Display (HUD) and Head-Down Displays (HDD) with SVS is contrasted to baseline standard head down displays in terms of induced workload and pilot behavior in 1400 RVR visibility levels. Variances across performance and pilot behavior were reviewed for acceptability when using HUD or HDD with SVS under reduced minimums to acquire the necessary visual components to continue to land. The data suggest superior performance for HUD implementations. Improved attentional behavior is also suggested for HDD implementations of SVS for low-visibility approach and landing operations.

A digitally implemented phase-locked loop detection scheme for analysis of the phase and power stability of a calibration tone

NASA Technical Reports Server (NTRS)

Densmore, A. C.

1988-01-01

A digital phase-locked loop (PLL) scheme is described which detects the phase and power of a high SNR calibration tone. The digital PLL is implemented in software directly from the given description. It was used to evaluate the stability of the Goldstone Deep Space Station open loop receivers for Radio Science. Included is a derivative of the Allan variance sensitivity of the PLL imposed by additive white Gaussian noise; a lower limit is placed on the carrier frequency.

The advantage of short paper titles

PubMed Central

Letchford, Adrian; Moat, Helen Susannah; Preis, Tobias

2015-01-01

Vast numbers of scientific articles are published each year, some of which attract considerable attention, and some of which go almost unnoticed. Here, we investigate whether any of this variance can be explained by a simple metric of one aspect of the paper's presentation: the length of its title. Our analysis provides evidence that journals which publish papers with shorter titles receive more citations per paper. These results are consistent with the intriguing hypothesis that papers with shorter titles may be easier to understand, and hence attract more citations. PMID:26361556

27 CFR 40.202 - Reports.

Code of Federal Regulations, 2010 CFR

2010-04-01

... TOBACCO Operations by Manufacturers of Tobacco Products Inventories and Reports § 40.202 Reports. (a... shall be made regardless of whether any operations or transactions occurred during the month or portion...) Manufactured, (2) Received in bond, (3) Received by return to bond, (4) Disclosed by inventory as an overage...

The efficacy of planetarium experiences to teach specific science concepts

NASA Astrophysics Data System (ADS)

Palmer, Joel C.

The purpose of this study was to examine the impact of planetarium experiences on students' understanding of phases of the moon and eclipses. This research employed a quasi-experimental design. Students from 12 classes in four different schools all in the same school district participated in the study. A total of 178 students from four teachers participated in the study. Data were collected using a researcher developed pretest and posttest. All students received classroom instruction based on the school district's curriculum. The experimental groups took the posttest after attending a 45-minute planetarium experience titled Moon Witch. The control groups took the posttest before attending the planetarium experience but after receiving an additional 45-minute lesson on phases of the moon and eclipses. The data were analyzed using the Statistical Package for Social Sciences (SPSS). An Analysis of Variance (ANOVA) was run to determine if there was variance among teachers' instructional practices. Since the results indicated there was no significant variance among teachers, the study sample was analyzed as a single group. An Independent Samples t Test for Means was run in SPSS for the study sample and each subgroup. Subgroups were African American, Hispanic, White, Male, Female, and Economically Disadvantaged. The results indicated that there was an improvement on mean gain scores for the experimental group over the control group for all students and each subgroup. The differences in mean gain scores were significantly higher for all students and for the African American, Female, and Economically Disadvantaged subgroups. An Independent Samples t Test for Means was run using SPSS for each of the three different sections of the pretest and posttest. The results indicated that most of the improvement was in Section 3. This section required students to manipulate photos of the phases of moon into correct order. This section required more spatial reasoning than Section 1, multiple-choice, or Section 2, essay. Results indicate that planetarium experiences improved students' understanding of phases of the moon and eclipses. There was evidence that this improvement was facilitated by the planetarium's ability to create visual representations that students would otherwise have to create mentally.

Titration of Intravenous Oxytocin Infusion for Postdates Induction of Labor Across Body Mass Index Groups.

PubMed

Maeder, Angela B; Vonderheid, Susan C; Park, Chang G; Bell, Aleeca F; McFarlin, Barbara L; Vincent, Catherine; Carter, C Sue

To evaluate whether oxytocin titration for postdates labor induction differs among women who are normal weight, overweight, and obese and whether length of labor and birth method differ by oxytocin titration and body mass index (BMI). Retrospective cohort study. U.S. university-affiliated hospital. Of 280 eligible women, 21 were normal weight, 134 were overweight, and 125 were obese at labor admission. Data on women who received oxytocin for postdates induction between January 1, 2013 and June 30, 2013 were extracted from medical records. Oxytocin administration and labor outcomes were compared across BMI groups, controlling for potential confounders. Data were analyzed using χ 2 , analysis of variance, analysis of covariance, and multiple linear and logistic regression models. Women who were obese received more oxytocin than women who were overweight in the unadjusted analysis of variance (7.50 units compared with 5.92 units, p = .031). Women who were overweight had more minutes between rate changes from initiation to maximum than women who were obese (98.19 minutes compared with 83.39 minutes, p = .038). Length of labor increased with BMI (p = .018), with a mean length of labor for the normal weight group of 13.96 hours (standard deviation = 8.10); for the overweight group, 16.00 hours (standard deviation = 7.54); and for the obese group, 18.30 hours (standard deviation = 8.65). Cesarean rate increased with BMI (p = .001), with 4.8% of normal weight, 33.6% of overweight, and 42.4% of obese women having cesarean births. Women who were obese and experienced postdates labor induction received more oxytocin than women who were non-obese and had longer length of labor and greater cesarean rates. Copyright © 2017 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses. Published by Elsevier Inc. All rights reserved.

Development of an Ultra-Wideband Receiver for the North America Array

NASA Astrophysics Data System (ADS)

Velazco, J. E.; Soriano, M.; Hoppe, D.; Russell, D.; D'Addario, L.; Long, E.; Bowen, J.; Samoska, L.; Lazio, J.

2016-11-01

The North America Array (NAA) is a concept for a radio astronomical interferometric array operating in the 1.2 GHz to 116 GHz frequency range. It has been designed to provide substantial improvements in sensitivity, angular resolution, and frequency coverage beyond the current Karl G. Jansky Very Large Array (VLA). It will have a continuous frequency coverage of 1.2 GHz to 50 GHz and 70 to 116 GHz, and a total aperture 10 times more sensitive than the VLA (and 25 times more sensitive than a 34-m-diameter antenna of the Deep Space Network [DSN]). One of the key goals for the NAA is to reduce the operating costs without sacrificing performance. We are designing an ultra-wideband receiver package designed to operate across the 8 to 48 GHz frequency range in contrast to the current VLA, which covers this frequency range with five receiver packages. Reducing the number of receiving systems required to cover the full frequency range would reduce operating costs. To minimize implementation, operational, and maintenance costs, we are developing a receiver that is compact, simple to assemble, and that consumes less power. The objective of this work is to develop a prototype integrated feed-receiver package with a sensitivity performance comparable to current narrower-band systems on radio telescopes and the DSN, but with a design that meets the requirement of low long-term operational costs. The ultra-wideband receiver package consists of a feedhorn, low-noise amplifier (LNA), and downconverters to analog intermediate frequencies. Both the feedhorn and the LNA are cryogenically cooled. Key features of this design are a quad-ridge feedhorn with dielectric loading and a cryogenic receiver with a noise temperature of no more than 30°K at the low end of the band. In this article, we report on the status of this receiver package development, including the feed design and LNA implementation. We present simulation studies of the feed horn carried out to optimize illumination efficiencies across the band of interest. In addition, we show experimental results of low-noise 70-nm gallium arsenide, metamorphic high-electron-mobility-transistor (HEMT) amplifier testing performed across the 1 to 18 GHz frequency range. Also presented are 8 to 48 GHz simulation results for 35-nm indium phosphide HEMT amplifiers.

The Army Meter Data Management System (MDMS): A Case Study for Army MDMS Pilot

DTIC Science & Technology

2011-05-11

Academy (West Point, NY) • Meets DoD cyber-security requirements – Received Authority to Operate from Army NETCOM effective 23 April 2010 – Received...to Operate on DoD network – Received ATO from Army NETCOM effective 23 April 2010 – Received CoN from Army NETCOM on 26 July 2010 • Over 195 meters...SCH~ From I Aug 2010001D To 8 Aug 2010 00 00 En•l’iY f*ttk COnWtnptlon J96S9U81’ WII FillCilftl .. Totol , ......... ~ Metert - Met el\\ r;’l

A Brayton cycle solar dynamic heat receiver for space

NASA Technical Reports Server (NTRS)

Sedgwick, L. M.; Nordwall, H. L.; Kaufmann, K. J.; Johnson, S. D.

1989-01-01

The detailed design of a heat receiver developed to meet the requirements of the Space Station Freedom, which will be assembled and operated in low earth orbit beginning in the mid-1990's, is described. The heat receiver supplies thermal energy to a nominal 25-kW closed-Brayton-cycle power conversion unit. The receiver employs an integral thermal energy storage system utilizing the latent heat of a eutectic-salt phase-change mixture to store energy for eclipse operation. The salt is contained within a felt metal matrix which enhances heat transfer and controls the salt void distribution during solidification.

Dynamic Battlefield Visualization: Knowledge Management in a Complex, Emergent PMESII-PT Battlefield

DTIC Science & Technology

2009-06-01

organizations was articulated over two decades ago by Jerome Bruner (1986). Specifically, he argued that humans employ two distinctive modes of...narrative knowledge underscored by the writings of Jerome Bruner , Karl Weick, Laurence Prusak, and John Seely Brown. Finally, it consistently supports...a known battle calculus) and ambiguity (pattern/trend analysis to reveal operational variances or to discover influence mechanisms that can be

Network acceleration techniques

NASA Technical Reports Server (NTRS)

Crowley, Patricia (Inventor); Maccabe, Arthur Barney (Inventor); Awrach, James Michael (Inventor)

2012-01-01

Splintered offloading techniques with receive batch processing are described for network acceleration. Such techniques offload specific functionality to a NIC while maintaining the bulk of the protocol processing in the host operating system ("OS"). The resulting protocol implementation allows the application to bypass the protocol processing of the received data. Such can be accomplished this by moving data from the NIC directly to the application through direct memory access ("DMA") and batch processing the receive headers in the host OS when the host OS is interrupted to perform other work. Batch processing receive headers allows the data path to be separated from the control path. Unlike operating system bypass, however, the operating system still fully manages the network resource and has relevant feedback about traffic and flows. Embodiments of the present disclosure can therefore address the challenges of networks with extreme bandwidth delay products (BWDP).

Passive thermo-optic feedback for robust athermal photonic systems

DOEpatents

Rakich, Peter T.; Watts, Michael R.; Nielson, Gregory N.

2015-06-23

Thermal control devices, photonic systems and methods of stabilizing a temperature of a photonic system are provided. A thermal control device thermally coupled to a substrate includes a waveguide for receiving light, an absorption element optically coupled to the waveguide for converting the received light to heat and an optical filter. The optical filter is optically coupled to the waveguide and thermally coupled to the absorption element. An operating point of the optical filter is tuned responsive to the heat from the absorption element. When the operating point is less than a predetermined temperature, the received light is passed to the absorption element via the optical filter. When the operating point is greater than or equal to the predetermined temperature, the received light is transmitted out of the thermal control device via the optical filter, without being passed to the absorption element.

A bivariate contaminated binormal model for robust fitting of proper ROC curves to a pair of correlated, possibly degenerate, ROC datasets.

PubMed

Zhai, Xuetong; Chakraborty, Dev P

2017-06-01

The objective was to design and implement a bivariate extension to the contaminated binormal model (CBM) to fit paired receiver operating characteristic (ROC) datasets-possibly degenerate-with proper ROC curves. Paired datasets yield two correlated ratings per case. Degenerate datasets have no interior operating points and proper ROC curves do not inappropriately cross the chance diagonal. The existing method, developed more than three decades ago utilizes a bivariate extension to the binormal model, implemented in CORROC2 software, which yields improper ROC curves and cannot fit degenerate datasets. CBM can fit proper ROC curves to unpaired (i.e., yielding one rating per case) and degenerate datasets, and there is a clear scientific need to extend it to handle paired datasets. In CBM, nondiseased cases are modeled by a probability density function (pdf) consisting of a unit variance peak centered at zero. Diseased cases are modeled with a mixture distribution whose pdf consists of two unit variance peaks, one centered at positive μ with integrated probability α, the mixing fraction parameter, corresponding to the fraction of diseased cases where the disease was visible to the radiologist, and one centered at zero, with integrated probability (1-α), corresponding to disease that was not visible. It is shown that: (a) for nondiseased cases the bivariate extension is a unit variances bivariate normal distribution centered at (0,0) with a specified correlation ρ 1 ; (b) for diseased cases the bivariate extension is a mixture distribution with four peaks, corresponding to disease not visible in either condition, disease visible in only one condition, contributing two peaks, and disease visible in both conditions. An expression for the likelihood function is derived. A maximum likelihood estimation (MLE) algorithm, CORCBM, was implemented in the R programming language that yields parameter estimates and the covariance matrix of the parameters, and other statistics. A limited simulation validation of the method was performed. CORCBM and CORROC2 were applied to two datasets containing nine readers each contributing paired interpretations. CORCBM successfully fitted the data for all readers, whereas CORROC2 failed to fit a degenerate dataset. All fits were visually reasonable. All CORCBM fits were proper, whereas all CORROC2 fits were improper. CORCBM and CORROC2 were in agreement (a) in declaring only one of the nine readers as having significantly different performances in the two modalities; (b) in estimating higher correlations for diseased cases than for nondiseased ones; and (c) in finding that the intermodality correlation estimates for nondiseased cases were consistent between the two methods. All CORCBM fits yielded higher area under curve (AUC) than the CORROC2 fits, consistent with the fact that a proper ROC model like CORCBM is based on a likelihood-ratio-equivalent decision variable, and consequently yields higher performance than the binormal model-based CORROC2. The method gave satisfactory fits to four simulated datasets. CORCBM is a robust method for fitting paired ROC datasets, always yielding proper ROC curves, and able to fit degenerate datasets. © 2017 American Association of Physicists in Medicine.

Applying Bayesian Modeling and Receiver Operating Characteristic Methodologies for Test Utility Analysis

ERIC Educational Resources Information Center

Wang, Qiu; Diemer, Matthew A.; Maier, Kimberly S.

2013-01-01

This study integrated Bayesian hierarchical modeling and receiver operating characteristic analysis (BROCA) to evaluate how interest strength (IS) and interest differentiation (ID) predicted low–socioeconomic status (SES) youth's interest-major congruence (IMC). Using large-scale Kuder Career Search online-assessment data, this study fit three…

26 CFR 1.132-7 - Employer-operated eating facilities.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Employer-operated eating facilities. (a) In general—(1) Condition for exclusion—(i) General rule. The value... determine the number of meals received by volunteers who receive food and beverages at a hospital, free or... volunteers. If an employer charges nonemployees a greater amount than employees, in determining whether the...