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Sample records for accuracy positive predictive

  1. Position of helical kinks in membrane protein crystal structures and the accuracy of computational prediction.

    PubMed

    Hall, Spencer E; Roberts, Kyle; Vaidehi, Nagarajan

    2009-01-01

    The structural features of helical transmembrane (TM) proteins, such as helical kinks, tilts, and rotational orientations are important in modulation of their function and these structural features give rise to functional diversity in membrane proteins with similar topology. In particular, the helical kinks caused by breaking of the backbone hydrogen bonds lead to hinge bending flexibility in these helices. Therefore it is important to understand the nature of the helical kinks and to be able to reproduce these kinks in structural models of membrane proteins. We have analyzed the position and extent of helical kinks in the transmembrane helices of all the crystal structures of membrane proteins taken from the MPtopo database, which are about 405 individual helices of length between 19 and 35 residues. 44% of the crystal structures of TM helices showed a significant helical kink, and 35% of these kinks are caused by prolines. Many of the non-proline helical kinks are caused by other residues like Ser and Gly that are located at the center of helical kinks. The side chain of Ser makes a hydrogen bond with the main chain carbonyl of the i - 4th or i + 4th residue thus making a kink. We have also studied how well molecular dynamics (MD) simulations on isolated helices can reproduce the position of the helical kinks in TM helices. Such a method is useful for structure prediction of membrane proteins. We performed MD simulations, starting from a canonical helix for the 405 TM helices. 1 ns of MD simulation results show that we can reproduce about 79% of the proline kinks, only 59% of the vestigial proline kinks and 18% of the non-proline helical kinks. We found that similar results can be obtained from choosing the lowest potential energy structure from the MD simulation. 4-14% more of the vestigial prolines were reproduced by replacing them with prolines before performing MD simulations, and changing the amino acid back to proline after the MD simulations. From these

  2. Astronomic Position Accuracy Capability Study.

    DTIC Science & Technology

    1979-10-01

    portion of F. E. Warren AFB, Wyoming. The three points were called THEODORE ECC , TRACY, and JIM and consisted of metal tribrachs plastered to cinder...sets were computed as a deviation from the standard. Accuracy figures were determined from these residuals. Homo - geneity of variances was tested using

  3. Advancing the prediction accuracy of protein-protein interactions by utilizing evolutionary information from position-specific scoring matrix and ensemble classifier.

    PubMed

    Wang, Lei; You, Zhu-Hong; Xia, Shi-Xiong; Liu, Feng; Chen, Xing; Yan, Xin; Zhou, Yong

    2017-04-07

    Protein-Protein Interactions (PPIs) are essential to most biological processes and play a critical role in most cellular functions. With the development of high-throughput biological techniques and in silico methods, a large number of PPI data have been generated for various organisms, but many problems remain unsolved. These factors promoted the development of the in silico methods based on machine learning to predict PPIs. In this study, we propose a novel method by combining ensemble Rotation Forest (RF) classifier and Discrete Cosine Transform (DCT) algorithm to predict the interactions among proteins. Specifically, the protein amino acids sequence is transformed into Position-Specific Scoring Matrix (PSSM) containing biological evolution information, and then the feature vector is extracted to present protein evolutionary information using DCT algorithm; finally, the ensemble rotation forest model is used to predict whether a given protein pair is interacting or not. When performed on Yeast and H. pylori data sets, the proposed method achieved excellent results with an average accuracy of 98.54% and 88.27%. In addition, we achieved good prediction accuracy of 98.08%, 92.75%, 98.87% and 98.72% on independent data sets (C.elegans, E.coli, H.sapiens and M.musculus). In order to further evaluate the performance of our method, we compare it with the state-of-the-art Support Vector Machine (SVM) classifier and get good results. As a web server, the source code and Yeast data sets used in this article are freely available at http://202.119.201.126:8888/DCTRF/.

  4. Positional Accuracy Assessment of Googleearth in Riyadh

    NASA Astrophysics Data System (ADS)

    Farah, Ashraf; Algarni, Dafer

    2014-06-01

    Google Earth is a virtual globe, map and geographical information program that is controlled by Google corporation. It maps the Earth by the superimposition of images obtained from satellite imagery, aerial photography and GIS 3D globe. With millions of users all around the globe, GoogleEarth® has become the ultimate source of spatial data and information for private and public decision-support systems besides many types and forms of social interactions. Many users mostly in developing countries are also using it for surveying applications, the matter that raises questions about the positional accuracy of the Google Earth program. This research presents a small-scale assessment study of the positional accuracy of GoogleEarth® Imagery in Riyadh; capital of Kingdom of Saudi Arabia (KSA). The results show that the RMSE of the GoogleEarth imagery is 2.18 m and 1.51 m for the horizontal and height coordinates respectively.

  5. Positioning accuracy of the neurotron 1000

    SciTech Connect

    Cox, R.S.; Murphy, M.J.

    1995-12-31

    The Neuotron 1000 is a novel treatment machine under development for frameless stereotaxic radiosurgery that consists of a compact X-band accelerator mounted on a robotic arm. The therapy beam is guided to the lesion by an imaging system, which included two diagnostic x-ray cameras that view the patient during treatment. Patient position and motion are measured by the imaging system and appropriate corrections are communicated in real time to the robotic arm for beam targeting and motion tracking. The three tests reported here measured the pointing accuracy of the therapy beam and the present capability of the imaging guidance system. The positioning and pointing test measured the ability of the robotic arm to direct the beam through a test isocenter from arbitrary arm positions. The test isocenter was marked by a small light-sensitive crystal and the beam axis was simulated by a laser.

  6. Final Technical Report: Increasing Prediction Accuracy.

    SciTech Connect

    King, Bruce Hardison; Hansen, Clifford; Stein, Joshua

    2015-12-01

    PV performance models are used to quantify the value of PV plants in a given location. They combine the performance characteristics of the system, the measured or predicted irradiance and weather at a site, and the system configuration and design into a prediction of the amount of energy that will be produced by a PV system. These predictions must be as accurate as possible in order for finance charges to be minimized. Higher accuracy equals lower project risk. The Increasing Prediction Accuracy project at Sandia focuses on quantifying and reducing uncertainties in PV system performance models.

  7. Audiovisual biofeedback improves motion prediction accuracy

    PubMed Central

    Pollock, Sean; Lee, Danny; Keall, Paul; Kim, Taeho

    2013-01-01

    Purpose: The accuracy of motion prediction, utilized to overcome the system latency of motion management radiotherapy systems, is hampered by irregularities present in the patients’ respiratory pattern. Audiovisual (AV) biofeedback has been shown to reduce respiratory irregularities. The aim of this study was to test the hypothesis that AV biofeedback improves the accuracy of motion prediction. Methods: An AV biofeedback system combined with real-time respiratory data acquisition and MR images were implemented in this project. One-dimensional respiratory data from (1) the abdominal wall (30 Hz) and (2) the thoracic diaphragm (5 Hz) were obtained from 15 healthy human subjects across 30 studies. The subjects were required to breathe with and without the guidance of AV biofeedback during each study. The obtained respiratory signals were then implemented in a kernel density estimation prediction algorithm. For each of the 30 studies, five different prediction times ranging from 50 to 1400 ms were tested (150 predictions performed). Prediction error was quantified as the root mean square error (RMSE); the RMSE was calculated from the difference between the real and predicted respiratory data. The statistical significance of the prediction results was determined by the Student's t-test. Results: Prediction accuracy was considerably improved by the implementation of AV biofeedback. Of the 150 respiratory predictions performed, prediction accuracy was improved 69% (103/150) of the time for abdominal wall data, and 78% (117/150) of the time for diaphragm data. The average reduction in RMSE due to AV biofeedback over unguided respiration was 26% (p < 0.001) and 29% (p < 0.001) for abdominal wall and diaphragm respiratory motion, respectively. Conclusions: This study was the first to demonstrate that the reduction of respiratory irregularities due to the implementation of AV biofeedback improves prediction accuracy. This would result in increased efficiency of motion

  8. Predictive accuracy in the neuroprediction of rearrest

    PubMed Central

    Aharoni, Eyal; Mallett, Joshua; Vincent, Gina M.; Harenski, Carla L.; Calhoun, Vince D.; Sinnott-Armstrong, Walter; Gazzaniga, Michael S.; Kiehl, Kent A.

    2014-01-01

    A recently published study by the present authors (Aharoni et al., 2013) reported evidence that functional changes in the anterior cingulate cortex (ACC) within a sample of 96 criminal offenders who were engaged in a Go/No-Go impulse control task significantly predicted their rearrest following release from prison. In an extended analysis, we use discrimination and calibration techniques to test the accuracy of these predictions relative to more traditional models and their ability to generalize to new observations in both full and reduced models. Modest to strong discrimination and calibration accuracy were found, providing additional support for the utility of neurobiological measures in predicting rearrest. PMID:24720689

  9. Accuracy of maxillary positioning in bimaxillary surgery.

    PubMed

    Kretschmer, W B; Zoder, W; Baciut, G; Bacuit, Mihaela; Wangerin, K

    2009-09-01

    The aim of the study was to investigate the accuracy of a modified pin system for the vertical control of maxillary repositioning in bimaxillary osteotomies. The preoperative cephalograms of 239 consecutive patients who were to have bimaxillary osteotomies were superimposed on the postoperative films. Planned and observed vertical and horizontal movements of the upper incisor were analysed statistically. The mean deviations of -0.07 mm (95% confidence intervals (CIs) -0.17 to 0.04 mm) for the vertical movement and 0.12 mm (95% CI -0.06 to 0.30 mm) for the horizontal movement did not differ significantly from zero. Comparison of the two variances between intrusion and extrusion of the maxilla did not differ significantly either (p=0.51). These results suggest that the modified pin system for vertical control combined with interocclusal splints provides accurate vertical positioning of the anterior maxilla in orthognathic surgery.

  10. Time and position accuracy using codeless GPS

    NASA Technical Reports Server (NTRS)

    Dunn, C. E.; Jefferson, D. C.; Lichten, S. M.; Thomas, J. B.; Vigue, Y.; Young, L. E.

    1994-01-01

    The Global Positioning System has allowed scientists and engineers to make measurements having accuracy far beyond the original 15 meter goal of the system. Using global networks of P-Code capable receivers and extensive post-processing, geodesists have achieved baseline precision of a few parts per billion, and clock offsets have been measured at the nanosecond level over intercontinental distances. A cloud hangs over this picture, however. The Department of Defense plans to encrypt the P-Code (called Anti-Spoofing, or AS) in the fall of 1993. After this event, geodetic and time measurements will have to be made using codeless GPS receivers. However, there appears to be a silver lining to the cloud. In response to the anticipated encryption of the P-Code, the geodetic and GPS receiver community has developed some remarkably effective means of coping with AS without classified information. We will discuss various codeless techniques currently available and the data noise resulting from each. We will review some geodetic results obtained using only codeless data, and discuss the implications for time measurements. Finally, we will present the status of GPS research at JPL in relation to codeless clock measurements.

  11. A microwave position sensor with submillimeter accuracy

    NASA Astrophysics Data System (ADS)

    Stelzer, A.; Diskus, C. G.; Lubke, K.; Thim, H. W.

    1999-12-01

    Design and characteristics of a prototype distance sensor are presented in this paper. The radar front-end operates at 35 GHz and applies six-port technology and direct frequency measurement. The sensor makes use of both frequency-modulated continuous wave and interferometer principles and is capable of measuring distance with a very high accuracy of ±0.1 mm.

  12. Accuracy Improvement for Predicting Parkinson's Disease Progression.

    PubMed

    Nilashi, Mehrbakhsh; Ibrahim, Othman; Ahani, Ali

    2016-09-30

    Parkinson's disease (PD) is a member of a larger group of neuromotor diseases marked by the progressive death of dopamineproducing cells in the brain. Providing computational tools for Parkinson disease using a set of data that contains medical information is very desirable for alleviating the symptoms that can help the amount of people who want to discover the risk of disease at an early stage. This paper proposes a new hybrid intelligent system for the prediction of PD progression using noise removal, clustering and prediction methods. Principal Component Analysis (PCA) and Expectation Maximization (EM) are respectively employed to address the multi-collinearity problems in the experimental datasets and clustering the data. We then apply Adaptive Neuro-Fuzzy Inference System (ANFIS) and Support Vector Regression (SVR) for prediction of PD progression. Experimental results on public Parkinson's datasets show that the proposed method remarkably improves the accuracy of prediction of PD progression. The hybrid intelligent system can assist medical practitioners in the healthcare practice for early detection of Parkinson disease.

  13. Predicting Predictable: Accuracy and Reliability of Earthquake Forecasts

    NASA Astrophysics Data System (ADS)

    Kossobokov, V. G.

    2014-12-01

    Earthquake forecast/prediction is an uncertain profession. The famous Gutenberg-Richter relationship limits magnitude range of prediction to about one unit. Otherwise, the statistics of outcomes would be related to the smallest earthquakes and may be misleading when attributed to the largest earthquakes. Moreover, the intrinsic uncertainty of earthquake sizing allows self-deceptive picking of justification "just from below" the targeted magnitude range. This might be important encouraging evidence but, by no means, can be a "helpful" additive to statistics of a rigid testing that determines reliability and efficiency of a farecast/prediction method. Usually, earthquake prediction is classified in respect to expectation time while overlooking term-less identification of earthquake prone areas, as well as spatial accuracy. The forecasts are often made for a "cell" or "seismic region" whose area is not linked to the size of target earthquakes. This might be another source for making a wrong choice in parameterization of an forecast/prediction method and, eventually, for unsatisfactory performance in a real-time application. Summing up, prediction of time and location of an earthquake of a certain magnitude range can be classified into categories listed in the Table below - Classification of earthquake prediction accuracy Temporal, in years Spatial, in source zone size (L) Long-term 10 Long-range Up to 100 Intermediate-term 1 Middle-range 5-10 Short-term 0.01-0.1 Narrow-range 2-3 Immediate 0.001 Exact 1 Note that a wide variety of possible combinations that exist is much larger than usually considered "short-term exact" one. In principle, such an accurate statement about anticipated seismic extreme might be futile due to the complexities of the Earth's lithosphere, its blocks-and-faults structure, and evidently nonlinear dynamics of the seismic process. The observed scaling of source size and preparation zone with earthquake magnitude implies exponential scales for

  14. High accuracy autonomous navigation using the global positioning system (GPS)

    NASA Technical Reports Server (NTRS)

    Truong, Son H.; Hart, Roger C.; Shoan, Wendy C.; Wood, Terri; Long, Anne C.; Oza, Dipak H.; Lee, Taesul

    1997-01-01

    The application of global positioning system (GPS) technology to the improvement of the accuracy and economy of spacecraft navigation, is reported. High-accuracy autonomous navigation algorithms are currently being qualified in conjunction with the GPS attitude determination flyer (GADFLY) experiment for the small satellite technology initiative Lewis spacecraft. Preflight performance assessments indicated that these algorithms are able to provide a real time total position accuracy of better than 10 m and a velocity accuracy of better than 0.01 m/s, with selective availability at typical levels. It is expected that the position accuracy will be increased to 2 m if corrections are provided by the GPS wide area augmentation system.

  15. Alaska national hydrography dataset positional accuracy assessment study

    USGS Publications Warehouse

    Arundel, Samantha; Yamamoto, Kristina H.; Constance, Eric; Mantey, Kim; Vinyard-Houx, Jeremy

    2013-01-01

    Initial visual assessments Wide range in the quality of fit between features in NHD and these new image sources. No statistical analysis has been performed to actually quantify accuracy Determining absolute accuracy is cost prohibitive (must collect independent, well defined test points) Quantitative analysis of relative positional error is feasible.

  16. Parametric Characterization of SGP4 Theory and TLE Positional Accuracy

    NASA Astrophysics Data System (ADS)

    Oltrogge, D.; Ramrath, J.

    2014-09-01

    Two-Line Elements, or TLEs, contain mean element state vectors compatible with General Perturbations (GP) singly-averaged semi-analytic orbit theory. This theory, embodied in the SGP4 orbit propagator, provides sufficient accuracy for some (but perhaps not all) orbit operations and SSA tasks. For more demanding tasks, higher accuracy orbit and force model approaches (i.e. Special Perturbations numerical integration or SP) may be required. In recent times, the suitability of TLEs or GP theory for any SSA analysis has been increasingly questioned. Meanwhile, SP is touted as being of high quality and well-suited for most, if not all, SSA applications. Yet the lack of truth or well-known reference orbits that haven't already been adopted for radar and optical sensor network calibration has typically prevented a truly unbiased assessment of such assertions. To gain better insight into the practical limits of applicability for TLEs, SGP4 and the underlying GP theory, the native SGP4 accuracy is parametrically examined for the statistically-significant range of RSO orbit inclinations experienced as a function of all orbit altitudes from LEO through GEO disposal altitude. For each orbit altitude, reference or truth orbits were generated using full force modeling, time-varying space weather, and AGIs HPOP numerical integration orbit propagator. Then, TLEs were optimally fit to these truth orbits. The resulting TLEs were then propagated and positionally differenced with the truth orbits to determine how well the GP theory was able to fit the truth orbits. Resultant statistics characterizing these empirically-derived accuracies are provided. This TLE fit process of truth orbits was intentionally designed to be similar to the JSpOC process operationally used to generate Enhanced GP TLEs for debris objects. This allows us to draw additional conclusions of the expected accuracies of EGP TLEs. In the real world, Orbit Determination (OD) programs aren't provided with dense optical

  17. Influence of Ephemeris Error on GPS Single Point Positioning Accuracy

    NASA Astrophysics Data System (ADS)

    Lihua, Ma; Wang, Meng

    2013-09-01

    The Global Positioning System (GPS) user makes use of the navigation message transmitted from GPS satellites to achieve its location. Because the receiver uses the satellite's location in position calculations, an ephemeris error, a difference between the expected and actual orbital position of a GPS satellite, reduces user accuracy. The influence extent is decided by the precision of broadcast ephemeris from the control station upload. Simulation analysis with the Yuma almanac show that maximum positioning error exists in the case where the ephemeris error is along the line-of-sight (LOS) direction. Meanwhile, the error is dependent on the relationship between the observer and spatial constellation at some time period.

  18. Accuracy in fixing ship's positions by camera survey of bearings

    NASA Astrophysics Data System (ADS)

    Naus, Krzysztof; Wąż, Mariusz

    2011-01-01

    The paper presents the results of research on the possibilities of fixing ship position coordinates based on results of surveying bearings on navigational marks with the use of the CCD camera. Accuracy of the determination of ship position coordinates, expressed in terms of the mean error, was assumed to be the basic criterion of this estimation. The first part of the paper describes the method of the determination of the resolution and the mean error of the angle measurement, taken with a camera, and also the method of the determination of the mean error of position coordinates when two or more bearings were measured. There have been defined three software applications assigned for the development of navigational sea charts with accuracy areas mapped on. The second part contains the results of studying accuracy in fixing ship position coordinates, carried out in the Gulf of Gdansk, with the use of bearings taken obtained with the Rolleiflex and Sony cameras. The results are presented in a form of diagrams of the mean error of angle measurement, also in the form of navigational charts with accuracy fields mapped on. In the final part, basing on results obtained, the applicability of CCD cameras in automation of coastal navigation performance process is discussed.

  19. Assessing Predictive Accuracy in Discriminant Analysis.

    ERIC Educational Resources Information Center

    Huberty, Carl J.; And Others

    1987-01-01

    Three estimates of the probabilities of correct classification in predictive discriminant analysis were computed using mathematical formulas, resubstitution, and external analyses: (1) optimal hit rate; (2) actual hit rate; and (3) expected actual hit rate. Methods were compared using Monte Carlo sampling from two data sets. (Author/GDC)

  20. Low Cost, High Accuracy Positioning In Urban Environments

    NASA Astrophysics Data System (ADS)

    Hide, Chris; Moore, Terry; Hill, Chris; Park, David

    It is well known that GPS measurements are regularly obstructed in urban environments. Positioning accuracy in such environments is significantly degraded and in many areas, it is not possible to obtain a GPS position fix at all. There are currently two methods that can be used to improve availability in the urban environment. Firstly, GPS receivers can be augmented with dead reckoning sensors such as an INS. Alternatively, High Sensitivity GPS (HSGPS) receivers can be used which are able to acquire and track very weak signals. This paper assesses the performance obtained from a GPS and low cost INS integrated system and a HSGPS receiver in an urban environment in Nottingham, UK. The navigation systems are compared to a high accuracy integrated GPS/INS system which is used to provide a reference trajectory. It is demonstrated that the differential GPS and low cost INS system can provide horizontal positioning accuracy of better than 2·5 m RMS in real-time, and better than 1 m RMS in post-processing, whereas the non-differential HSGPS receiver provides a real-time performance of 5 m RMS. These results were obtained in an environment where, with conventional GPS receivers, a position solution is only available 48·4% of the time. Operational considerations such as initial alignment of the GPS and low cost INS are also discussed when comparing the two systems for urban positioning applications.

  1. Reticle flexure influence on pattern positioning accuracy for reticle writing

    NASA Astrophysics Data System (ADS)

    Hirano, Ryoichi; Matsuki, Kazuto; Yoshitake, Shusuke; Takahashi, Yoshihiko; Tamamushi, Shuichi; Ogawa, Yoji; Tojo, Toru

    1995-07-01

    This paper presents a method for estimating the influence of reticle flexure on pattern positioning accuracy, and evaluates the method by measuring patterned reticles. Reticle flexure causes the pattern shift which occurs by stretching or compression of the reticle surface. A height-mapping function of an electron beam (EB) writing system and a measuring machine are used to calculate the pattern shift due to reticle flexure. The bent shape of a reticle on the EB-writing system differs from that on the measuring machine, so that the patten shifts on the two machines are different. The pattern shifts caused by the bent shape difference were excluded from the measurement result of pattern positioning errors. The values of pattern positioning accuracy evaluation parameters, x, y-scaling and orthogonality, are calculated among several reticles (5 inches, 0.09 inches thick). The deviations of these three values are reduced to less than 50% of their uncompensated values.

  2. Accuracy of the LPM tracking system considering dynamic position changes.

    PubMed

    Ogris, Georg; Leser, Roland; Horsak, Brian; Kornfeind, Philipp; Heller, Mario; Baca, Arnold

    2012-01-01

    This study investigates the accuracy of the tracking system LPM (local position measurement). The goal was to determine detailed error values of the system in the context of sports performance analyses. Six moderately trained male soccer players (amateur level) performed 276 runs on three different courses at six different speeds. Additionally, ten small-sided game plays were carried out. All runs and game plays were recorded with the LPM tracking system and the motion capture system VICON simultaneously. VICON served as the reference system. The absolute error of all LPM position estimations was on average 23.4±20.7 cm. The estimation for average velocities varied between 0.01 km h(-1) and 0.23 km h(-1), the maximum speed estimations differed by up to 2.71 km h(-1). In addition, the results showed that the accuracy of the LPM system is highly dependent on the instantaneous dynamics of the player and decreases in the margins of the observation field. These dependencies were quantified. Considering commonly used applications of position tracking systems in sports (Leser, Ogris, & Baca, 2011), the accuracy of LPM is acceptable for position and velocity estimations. The system provides valuable results for average velocities but seems to be far less reliable when dealing with high dynamic movements and measuring instantaneous velocities.

  3. Positioning Accuracy in Otosurgery Measured with Optical Tracking

    PubMed Central

    Óvári, Attila; Neményi, Dóra; Just, Tino; Schuldt, Tobias; Buhr, Anne; Mlynski, Robert; Csókay, András; Pau, Hans-Wilhelm; Valálik, István

    2016-01-01

    Objectives To assess positioning accuracy in otosurgery and to test the impact of the two-handed instrument holding technique and the instrument support technique on surgical precision. To test an otologic training model with optical tracking. Study Design In total, 14 ENT surgeons in the same department with different levels of surgical experience performed static and dynamic tasks with otologic microinstruments under simulated otosurgical conditions. Methods Tip motion of the microinstrument was registered in three dimensions by optical tracking during 10 different tasks simulating surgical steps such as prosthesis crimping and dissection of the middle ear using formalin-fixed temporal bone. Instrument marker trajectories were compared within groups of experienced and less experienced surgeons performing uncompensated or compensated exercises. Results Experienced surgeons have significantly better positioning accuracy than novice ear surgeons in terms of mean displacement values of marker trajectories. The instrument support and the two-handed instrument holding techniques significantly reduce surgeons’ tremor. The laboratory set-up presented in this study provides precise feedback for otosurgeons about their surgical skills and proved to be a useful device for otosurgical training. Conclusions Simple tremor compensation techniques may offer trainees the potential to improve their positioning accuracy to the level of more experienced surgeons. Training in an experimental otologic environment with optical tracking may aid acquisition of technical skills in middle ear surgery and potentially shorten the learning curve. Thus, simulated exercises of surgical steps should be integrated into the training of otosurgeons. PMID:27027500

  4. Prediction of Rate Constants for Catalytic Reactions with Chemical Accuracy.

    PubMed

    Catlow, C Richard A

    2016-08-01

    Ex machina: A computational method for predicting rate constants for reactions within microporous zeolite catalysts with chemical accuracy has recently been reported. A key feature of this method is a stepwise QM/MM approach that allows accuracy to be achieved while using realistic models with accessible computer resources.

  5. Accuracy of distal radius positioning using an anatomical plate.

    PubMed

    Vroemen, Joy C; Dobbe, Johannes G G; Sierevelt, Inger N; Strackee, Simon D; Streekstra, Geert J

    2013-04-01

    Over the past decade, several anatomical plates have been introduced to improve the result of open reduction and internal fixation of the distal radius. Using 3-dimensional imaging techniques, the authors studied the accuracy and reproducibility of distal radius positioning using anatomical plates.Distal radius fractures and the correction of these fractures were simulated with plastic bone models of radii. The authors simulated a defect by removing an arbitrary wedge shape from the artificial radii. Two surgeons corrected these fractures by placing 2 anatomical plate types according to the plate manufacturers' instructions. The residual positioning errors of the distal segment in relation to the unaffected radii were determined using 3-dimensional imaging and were compared with naturally occurring bilateral radius differences in healthy individuals. In many cases, positioning does not agree with differences based on bilateral asymmetry in healthy patients.This study indicated the accuracy of anatomical plates. Positioning an anatomical plate may lead to considerable residual errors in individual patients. Volar distal radius plate shapes differ among plate manufacturers. Therefore, one plate may perform better than another in an individual.

  6. Dependence of Orbit Determination Accuracy on the Observer Position

    NASA Astrophysics Data System (ADS)

    Vananti, Alessandro; Schildknecht, Thomas

    2013-08-01

    The Astronomical Institute of the University of Bern (AIUB) is conducting several search campaigns for space debris in Geostationary (GEO) and Medium Earth Orbits (MEO). Usually, to improve the quality of the determined orbits for newly discovered objects, follow-up observations are conducted. The latter take place at different times during the discovery night or in subsequent nights. The time interval between the observations plays an important role in the accuracy of the calculated orbits. Another essential parameter to consider is the position of the observer at the observation time. In this paper, the accuracy of the orbit determination with respect to the position of the observer is analyzed. The same observing site at varying epochs or multiple site locations involve different distances from the target object and a different observing angle with respect to its orbital plane and trajectory. The formal error in the orbit determination process is, among other dependencies, a function of the latter parameters. The analysis of this dependence is important to choose the appropriate observation strategy. One of the main questions that arises is e.g. whether observing the same object from different stations results in better determined orbits and, if yes, how big is the improvement. Another question is e.g. whether the observation from multiple sites needs to be simultaneous or not for a better orbit accuracy.

  7. Electroelastic optical fiber positioning with submicrometer accuracy: Model and experiment

    NASA Astrophysics Data System (ADS)

    Kofod, Guggi; Mc Carthy, Denis N.; Krissler, Jan; Lang, Günter; Jordan, Grace

    2009-05-01

    We present accurate electromechanical measurements on a balanced push-pull dielectric elastomer actuator, demonstrating submicrometer accurate position control. An analytical model based on a simplified pure-shear dielectric elastomer film with prestretch is found to capture the voltage-displacement behavior, with reduced output due to the boundary conditions. Two complementary experiments show that actuation coefficients of 0.5-1 nm/V2 are obtainable with the demonstrated device, enabling motion control with submicrometer accuracy in a voltage range below 200 V.

  8. Accuracy of patient positioning in mantle field irradiation.

    PubMed

    Creutzberg, C L; Visser, A G; De Porre, P M; Meerwaldt, J H; Althof, V G; Levendag, P C

    1992-04-01

    A prospective study of the accuracy of patient positioning in mantle field irradiation was carried out in 13 lymphoma patients treated with curative radiotherapy. Patients were treated in the supine and prone position for anterior and posterior fields, respectively. Individually shaped divergent shielding blocks were placed in a fixed position in a template which was positioned on a tray above the patient. A total number of 94 megavoltage portal films (MV) was analysed and compared to 26 simulation films (SIM). MV-SIM differences were larger for posterior fields than for anterior fields. Regarding the position of the lung shielding blocks, mean MV-SIM differences ranged from 1.3 to 4.4 mm and errors exceeding 1 cm were found in 7.2% of cases. Most discrepancies appeared to be randomly distributed. A 4-5 mm systematic cranial shift of patients in the posterior treatment position was noted. Discrepancies in the position of the laryngeal block, spinal cord shielding block and humerus blocks were small with mean MV-SIM differences ranging from 0.3 to 2.7 mm. Differences between simulation set-up and treatment set-up were modest as compared to error rates reported in the literature. Shielding of tumour-bearing areas did not occur. It was concluded that the present standardised technique of patient positioning and the design of treatment fields results in acceptable error rates. Attention should be directed towards increasing the stability of patients in the prone treatment position in order to further reduce both systematic and random error rates.

  9. Cadastral Positioning Accuracy Improvement: a Case Study in Malaysia

    NASA Astrophysics Data System (ADS)

    Hashim, N. M.; Omar, A. H.; Omar, K. M.; Abdullah, N. M.; Yatim, M. H. M.

    2016-09-01

    Cadastral map is a parcel-based information which is specifically designed to define the limitation of boundaries. In Malaysia, the cadastral map is under authority of the Department of Surveying and Mapping Malaysia (DSMM). With the growth of spatial based technology especially Geographical Information System (GIS), DSMM decided to modernize and reform its cadastral legacy datasets by generating an accurate digital based representation of cadastral parcels. These legacy databases usually are derived from paper parcel maps known as certified plan. The cadastral modernization will result in the new cadastral database no longer being based on single and static parcel paper maps, but on a global digital map. Despite the strict process of the cadastral modernization, this reform has raised unexpected queries that remain essential to be addressed. The main focus of this study is to review the issues that have been generated by this transition. The transformed cadastral database should be additionally treated to minimize inherent errors and to fit them to the new satellite based coordinate system with high positional accuracy. This review result will be applied as a foundation for investigation to study the systematic and effectiveness method for Positional Accuracy Improvement (PAI) in cadastral database modernization.

  10. Accuracy of High Frequency Maximum Usable Frequencies (MUF) Prediction.

    DTIC Science & Technology

    1981-09-15

    Supplement 1 (NTP6 Supp. 1). This is a Navy publication designed to provide the operating personnel, establishing ship, shore and aircraft...OBCTIVE Assess the accuracy of predicted MJFs by prediction programs, commonly used in Navy applications, using a previously assembled data base of...Publication NTSS Navy Tactical Sounder System PROPHET Propagation Forecasting Terminal RADC Rome Air Development Center RMS Root Mean Square SRI Stanford

  11. Assessing genomic selection prediction accuracy in a dynamic barley breeding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genomic selection is a method to improve quantitative traits in crops and livestock by estimating breeding values of selection candidates using phenotype and genome-wide marker data sets. Prediction accuracy has been evaluated through simulation and cross-validation, however validation based on prog...

  12. Predictive Accuracy of Exercise Stress Testing the Healthy Adult.

    ERIC Educational Resources Information Center

    Lamont, Linda S.

    1981-01-01

    Exercise stress testing provides information on the aerobic capacity, heart rate, and blood pressure responses to graded exercises of a healthy adult. The reliability of exercise tests as a diagnostic procedure is discussed in relation to sensitivity and specificity and predictive accuracy. (JN)

  13. High accuracy operon prediction method based on STRING database scores.

    PubMed

    Taboada, Blanca; Verde, Cristina; Merino, Enrique

    2010-07-01

    We present a simple and highly accurate computational method for operon prediction, based on intergenic distances and functional relationships between the protein products of contiguous genes, as defined by STRING database (Jensen,L.J., Kuhn,M., Stark,M., Chaffron,S., Creevey,C., Muller,J., Doerks,T., Julien,P., Roth,A., Simonovic,M. et al. (2009) STRING 8-a global view on proteins and their functional interactions in 630 organisms. Nucleic Acids Res., 37, D412-D416). These two parameters were used to train a neural network on a subset of experimentally characterized Escherichia coli and Bacillus subtilis operons. Our predictive model was successfully tested on the set of experimentally defined operons in E. coli and B. subtilis, with accuracies of 94.6 and 93.3%, respectively. As far as we know, these are the highest accuracies ever obtained for predicting bacterial operons. Furthermore, in order to evaluate the predictable accuracy of our model when using an organism's data set for the training procedure, and a different organism's data set for testing, we repeated the E. coli operon prediction analysis using a neural network trained with B. subtilis data, and a B. subtilis analysis using a neural network trained with E. coli data. Even for these cases, the accuracies reached with our method were outstandingly high, 91.5 and 93%, respectively. These results show the potential use of our method for accurately predicting the operons of any other organism. Our operon predictions for fully-sequenced genomes are available at http://operons.ibt.unam.mx/OperonPredictor/.

  14. Methods for evaluating the predictive accuracy of structural dynamic models

    NASA Technical Reports Server (NTRS)

    Hasselman, Timothy K.; Chrostowski, Jon D.

    1991-01-01

    Modeling uncertainty is defined in terms of the difference between predicted and measured eigenvalues and eigenvectors. Data compiled from 22 sets of analysis/test results was used to create statistical databases for large truss-type space structures and both pretest and posttest models of conventional satellite-type space structures. Modeling uncertainty is propagated through the model to produce intervals of uncertainty on frequency response functions, both amplitude and phase. This methodology was used successfully to evaluate the predictive accuracy of several structures, including the NASA CSI Evolutionary Structure tested at Langley Research Center. Test measurements for this structure were within + one-sigma intervals of predicted accuracy for the most part, demonstrating the validity of the methodology and computer code.

  15. Researches on High Accuracy Prediction Methods of Earth Orientation Parameters

    NASA Astrophysics Data System (ADS)

    Xu, X. Q.

    2015-09-01

    The Earth rotation reflects the coupling process among the solid Earth, atmosphere, oceans, mantle, and core of the Earth on multiple spatial and temporal scales. The Earth rotation can be described by the Earth's orientation parameters, which are abbreviated as EOP (mainly including two polar motion components PM_X and PM_Y, and variation in the length of day ΔLOD). The EOP is crucial in the transformation between the terrestrial and celestial reference systems, and has important applications in many areas such as the deep space exploration, satellite precise orbit determination, and astrogeodynamics. However, the EOP products obtained by the space geodetic technologies generally delay by several days to two weeks. The growing demands for modern space navigation make high-accuracy EOP prediction be a worthy topic. This thesis is composed of the following three aspects, for the purpose of improving the EOP forecast accuracy. (1) We analyze the relation between the length of the basic data series and the EOP forecast accuracy, and compare the EOP prediction accuracy for the linear autoregressive (AR) model and the nonlinear artificial neural network (ANN) method by performing the least squares (LS) extrapolations. The results show that the high precision forecast of EOP can be realized by appropriate selection of the basic data series length according to the required time span of EOP prediction: for short-term prediction, the basic data series should be shorter, while for the long-term prediction, the series should be longer. The analysis also showed that the LS+AR model is more suitable for the short-term forecasts, while the LS+ANN model shows the advantages in the medium- and long-term forecasts. (2) We develop for the first time a new method which combines the autoregressive model and Kalman filter (AR+Kalman) in short-term EOP prediction. The equations of observation and state are established using the EOP series and the autoregressive coefficients

  16. Wind Prediction Accuracy for Air Traffic Management Decision Support Tools

    NASA Technical Reports Server (NTRS)

    Cole, Rod; Green, Steve; Jardin, Matt; Schwartz, Barry; Benjamin, Stan

    2000-01-01

    The performance of Air Traffic Management and flight deck decision support tools depends in large part on the accuracy of the supporting 4D trajectory predictions. This is particularly relevant to conflict prediction and active advisories for the resolution of conflicts and the conformance with of traffic-flow management flow-rate constraints (e.g., arrival metering / required time of arrival). Flight test results have indicated that wind prediction errors may represent the largest source of trajectory prediction error. The tests also discovered relatively large errors (e.g., greater than 20 knots), existing in pockets of space and time critical to ATM DST performance (one or more sectors, greater than 20 minutes), are inadequately represented by the classic RMS aggregate prediction-accuracy studies of the past. To facilitate the identification and reduction of DST-critical wind-prediction errors, NASA has lead a collaborative research and development activity with MIT Lincoln Laboratories and the Forecast Systems Lab of the National Oceanographic and Atmospheric Administration (NOAA). This activity, begun in 1996, has focussed on the development of key metrics for ATM DST performance, assessment of wind-prediction skill for state of the art systems, and development/validation of system enhancements to improve skill. A 13 month study was conducted for the Denver Center airspace in 1997. Two complementary wind-prediction systems were analyzed and compared to the forecast performance of the then standard 60 km Rapid Update Cycle - version 1 (RUC-1). One system, developed by NOAA, was the prototype 40-km RUC-2 that became operational at NCEP in 1999. RUC-2 introduced a faster cycle (1 hr vs. 3 hr) and improved mesoscale physics. The second system, Augmented Winds (AW), is a prototype en route wind application developed by MITLL based on the Integrated Terminal Wind System (ITWS). AW is run at a local facility (Center) level, and updates RUC predictions based on an

  17. Accuracy of the VO2peak prediction equation in firefighters

    PubMed Central

    2014-01-01

    Background A leading contributing factor to firefighter injury and death is lack of fitness. Therefore, the Fire Service Joint Labor Management Wellness-Fitness Initiative (WFI) was established that includes a focus on providing fitness assessments to all fire service personnel. The current fitness assessment includes a submaximal exercise test protocol and associated prediction equation to predict individual VO2peak as a measure of fitness. There is limited information on the accuracy, precision, and sources of error of this prediction equation. This study replicated previous research by validating the accuracy of the WFI VO2peak prediction equation for a group of firefighters and further examining potential sources of error for an individual firefighters’ assessment. Methods The sample consisted of 22 firefighters who completed a maximal exercise test protocol similar to the WFI submaximal protocol, but the test was terminated when firefighters reached a maximal level of exertion (i.e., measured VO2peak). We then calculated the predicted VO2peak based on the WFI prediction equation along with individual firefighters’ body mass index (BMI) and 85% of maximum heart rate. The data were analyzed using paired samples t-tests in SPSS v. 21.0. Results The difference between predicted and measured VO2peak was -0.77 ± 8.35 mL•kg-1•min-1. However, there was a weak, statistically non-significant association between measured VO2peak and predicted VO2peak (R2 = 0.09, F(1,21) = 2.05, p = 0.17). The intraclass correlation coefficient (ICC = 0.215, p > 0.05) and Pearson (r = 0.31, p = 0.17) and Spearman (ρ = 0.28, p = 0.21) correlation coefficients were small. The standard error of the estimate (SEE) was 8.5 mL•kg-1•min-1. Further, both age and baseline fitness level were associated with increased inaccuracy of the prediction equation. Conclusions We provide data on the inaccuracy and sources of error for the WFI VO2peak

  18. Using Genetic Distance to Infer the Accuracy of Genomic Prediction

    PubMed Central

    Scutari, Marco; Mackay, Ian

    2016-01-01

    The prediction of phenotypic traits using high-density genomic data has many applications such as the selection of plants and animals of commercial interest; and it is expected to play an increasing role in medical diagnostics. Statistical models used for this task are usually tested using cross-validation, which implicitly assumes that new individuals (whose phenotypes we would like to predict) originate from the same population the genomic prediction model is trained on. In this paper we propose an approach based on clustering and resampling to investigate the effect of increasing genetic distance between training and target populations when predicting quantitative traits. This is important for plant and animal genetics, where genomic selection programs rely on the precision of predictions in future rounds of breeding. Therefore, estimating how quickly predictive accuracy decays is important in deciding which training population to use and how often the model has to be recalibrated. We find that the correlation between true and predicted values decays approximately linearly with respect to either FST or mean kinship between the training and the target populations. We illustrate this relationship using simulations and a collection of data sets from mice, wheat and human genetics. PMID:27589268

  19. Predicting Nucleosome Positioning Using Multiple Evidence Tracks

    NASA Astrophysics Data System (ADS)

    Reynolds, Sheila M.; Weng, Zhiping; Bilmes, Jeff A.; Noble, William Stafford

    We describe a probabilistic model, implemented as a dynamic Bayesian network, that can be used to predict nucleosome positioning along a chromosome based on one or more genomic input tracks containing position-specific information (evidence). Previous models have either made predictions based on primary DNA sequence alone, or have been used to infer nucleosome positions from experimental data. Our framework permits the combination of these two distinct types of information. We show how this flexible framework can be used to make predictions based on either sequence-model scores or experimental data alone, or by using the two in combination to interpret the experimental data and fill in gaps. The model output represents the posterior probability, at each position along the chromosome, that a nucleosome core overlaps that position, given the evidence. This posterior probability is computed by integrating the information contained in the input evidence tracks along the entire input sequence, and fitting the evidence to a simple grammar of alternating nucleosome cores and linkers. In addition to providing a novel mechanism for the prediction of nucleosome positioning from arbitrary heterogeneous data sources, this framework is also applicable to other genomic segmentation tasks in which local scores are available from models or from data that can be interpreted as defining a probability assignment over labels at that position. The ability to combine sequence-based predictions and data from experimental assays is a significant and novel contribution to the ongoing research regarding the primary structure of chromatin and its effects upon gene regulation.

  20. Positioning accuracy of primary mirror actuators for large-aperture space-based optical instruments

    NASA Astrophysics Data System (ADS)

    Hatheway, Alson E.

    2000-10-01

    This paper describes the Rubicontm actuator, discusses its test data and derives from the data the actuator's accuracy function based upon the observed accuracy of long and short stroke motion commands. The accuracy is described in terms of the rms positioning error (in nanometers) for moves of a given size, regardless of position in the stroke.

  1. Improved Discrimination of Influenza Forecast Accuracy Using Consecutive Predictions

    PubMed Central

    Shaman, Jeffrey; Kandula, Sasikiran

    2015-01-01

    Introduction: The ability to predict the growth and decline of infectious disease incidence has advanced considerably in recent years. In particular, accurate forecasts of influenza epidemiology have been developed using a number of approaches. Methods: Within our own group we produce weekly operational real-time forecasts of influenza at the municipal and state level in the U.S. These forecasts are generated using ensemble simulations depicting local influenza transmission dynamics, which have been optimized prior to forecast with observations of influenza incidence and data assimilation methods. The expected accuracy of a given forecast can be inferred in real-time through quantification of the agreement (e.g. the variance) among the ensemble of simulations. Results: Here we show that forecast expected accuracy can be further discriminated with the additional consideration of the streak or persistence of the forecast—the number of consecutive weeks the forecast has converged to the same outcome. Discussion: The findings indicate that the use of both the streak and ensemble agreement provides a more detailed and informative assessment of forecast expected accuracy. PMID:26512336

  2. Modelled three-dimensional suction accuracy predicts prey capture success in three species of centrarchid fishes

    PubMed Central

    Kane, Emily A.; Higham, Timothy E.

    2014-01-01

    Prey capture is critical for survival, and differences in correctly positioning and timing a strike (accuracy) are likely related to variation in capture success. However, an ability to quantify accuracy under natural conditions, particularly for fishes, is lacking. We developed a predictive model of suction hydrodynamics and applied it to natural behaviours using three-dimensional kinematics of three centrarchid fishes capturing evasive and non-evasive prey. A spheroid ingested volume of water (IVW) with dimensions predicted by peak gape and ram speed was verified with known hydrodynamics for two species. Differences in capture success occurred primarily with evasive prey (64–96% success). Micropterus salmoides had the greatest ram and gape when capturing evasive prey, resulting in the largest and most elongate IVW. Accuracy predicted capture success, although other factors may also be important. The lower accuracy previously observed in M. salmoides was not replicated, but this is likely due to more natural conditions in our study. Additionally, we discuss the role of modulation and integrated behaviours in shaping the IVW and determining accuracy. With our model, accuracy is a more accessible performance measure for suction-feeding fishes, which can be used to explore macroevolutionary patterns of prey capture evolution. PMID:24718455

  3. How a GNSS Receiver Is Held May Affect Static Horizontal Position Accuracy.

    PubMed

    Weaver, Steven A; Ucar, Zennure; Bettinger, Pete; Merry, Krista

    2015-01-01

    The static horizontal position accuracy of a mapping-grade GNSS receiver was tested in two forest types over two seasons, and subsequently was tested in one forest type against open sky conditions in the winter season. The main objective was to determine whether the holding position during data collection would result in significantly different static horizontal position accuracy. Additionally, we wanted to determine whether the time of year (season), forest type, or environmental variables had an influence on accuracy. In general, the F4Devices Flint GNSS receiver was found to have mean static horizontal position accuracy levels within the ranges typically expected for this general type of receiver (3 to 5 m) when differential correction was not employed. When used under forest cover, in some cases the GNSS receiver provided a higher level of static horizontal position accuracy when held vertically, as opposed to held at an angle or horizontally (the more natural positions), perhaps due to the orientation of the antenna within the receiver, or in part due to multipath or the inability to use certain satellite signals. Therefore, due to the fact that numerous variables may affect static horizontal position accuracy, we only conclude that there is weak to moderate evidence that the results of holding position are significant. Statistical test results also suggest that the season of data collection had no significant effect on static horizontal position accuracy, and results suggest that atmospheric variables had weak correlation with horizontal position accuracy. Forest type was found to have a significant effect on static horizontal position accuracy in one aspect of one test, yet otherwise there was little evidence that forest type affected horizontal position accuracy. Since the holding position was found in some cases to be significant with regard to the static horizontal position accuracy of positions collected in forests, it may be beneficial to have an

  4. Accuracy Improvement for Predicting Parkinson’s Disease Progression

    PubMed Central

    Nilashi, Mehrbakhsh; Ibrahim, Othman; Ahani, Ali

    2016-01-01

    Parkinson’s disease (PD) is a member of a larger group of neuromotor diseases marked by the progressive death of dopamineproducing cells in the brain. Providing computational tools for Parkinson disease using a set of data that contains medical information is very desirable for alleviating the symptoms that can help the amount of people who want to discover the risk of disease at an early stage. This paper proposes a new hybrid intelligent system for the prediction of PD progression using noise removal, clustering and prediction methods. Principal Component Analysis (PCA) and Expectation Maximization (EM) are respectively employed to address the multi-collinearity problems in the experimental datasets and clustering the data. We then apply Adaptive Neuro-Fuzzy Inference System (ANFIS) and Support Vector Regression (SVR) for prediction of PD progression. Experimental results on public Parkinson’s datasets show that the proposed method remarkably improves the accuracy of prediction of PD progression. The hybrid intelligent system can assist medical practitioners in the healthcare practice for early detection of Parkinson disease. PMID:27686748

  5. Prediction Accuracy of Error Rates for MPTB Space Experiment

    NASA Technical Reports Server (NTRS)

    Buchner, S. P.; Campbell, A. B.; Davis, D.; McMorrow, D.; Petersen, E. L.; Stassinopoulos, E. G.; Ritter, J. C.

    1998-01-01

    This paper addresses the accuracy of radiation-induced upset-rate predictions in space using the results of ground-based measurements together with standard environmental and device models. The study is focused on two part types - 16 Mb NEC DRAM's (UPD4216) and 1 Kb SRAM's (AMD93L422) - both of which are currently in space on board the Microelectronics and Photonics Test Bed (MPTB). To date, ground-based measurements of proton-induced single event upset (SEM cross sections as a function of energy have been obtained and combined with models of the proton environment to predict proton-induced error rates in space. The role played by uncertainties in the environmental models will be determined by comparing the modeled radiation environment with the actual environment measured aboard MPTB. Heavy-ion induced upsets have also been obtained from MPTB and will be compared with the "predicted" error rate following ground testing that will be done in the near future. These results should help identify sources of uncertainty in predictions of SEU rates in space.

  6. Accuracy of Wind Prediction Methods in the California Sea Breeze

    NASA Astrophysics Data System (ADS)

    Sumers, B. D.; Dvorak, M. J.; Ten Hoeve, J. E.; Jacobson, M. Z.

    2010-12-01

    In this study, we investigate the accuracy of measure-correlate-predict (MCP) algorithms and log law/power law scaling using data from two tall towers in coastal environments. We find that MCP algorithms accurately predict sea breeze winds and that log law/power law scaling methods struggle to predict 50-meter wind speeds. MCP methods have received significant attention as the wind industry has grown and the ability to accurately characterize the wind resource has become valuable. These methods are used to produce longer-term wind speed records from short-term measurement campaigns. A correlation is developed between the “target site,” where the developer is interested in building wind turbines, and a “reference site,” where long-term wind data is available. Up to twenty years of prior wind speeds are then are predicted. In this study, two existing MCP methods - linear regression and Mortimer’s method - are applied to predict 50-meter wind speeds at sites in the Salinas Valley and Redwood City, CA. The predictions are then verified with tall tower data. It is found that linear regression is poorly suited to MCP applications as the process produces inaccurate estimates of the cube of the wind speed at 50 meters. Meanwhile, Mortimer’s method, which bins data by direction and speed, is found to accurately predict the cube of the wind speed in both sea breeze and non-sea breeze conditions. We also find that log and power law are unstable predictors of wind speeds. While these methods produced accurate estimates of the average 50-meter wind speed at both sites, they predicted an average cube of the wind speed that was between 1.3 and 1.18 times the observed value. Inspection of time-series error reveals increased error in the mid-afternoon of the summer. This suggests that the cold sea breeze may disrupt the vertical temperature profile, create a stable atmosphere and violate the assumptions that allow log law scaling to work.

  7. Analysis of Current Position Determination Accuracy in Natural Resources Canada Precise Point Positioning Service

    NASA Astrophysics Data System (ADS)

    Krzan, Grzegorz; Dawidowicz, Karol; Krzysztof, Świaţek

    2013-09-01

    Precise Point Positioning (PPP) is a technique used to determine highprecision position with a single GNSS receiver. Unlike DGPS or RTK, satellite observations conducted by the PPP technique are not differentiated, therefore they require that parameter models should be used in data processing, such as satellite clock and orbit corrections. Apart from explaining the theory of the PPP technique, this paper describes the available web-based online services used in the post-processing of observation results. The results obtained in the post-processing of satellite observations at three points, with different characteristics of environment conditions, using the CSRS-PPP service, will be presented as the results of the experiment. This study examines the effect of the duration of the measurement session on the results and compares the results obtained by working out observations made by the GPS system and the combined observations from GPS and GLONASS. It also presents the analysis of the position determination accuracy using one and two measurement frequencies

  8. On the Accuracy of Probabilistic Bucking Load Prediction

    NASA Technical Reports Server (NTRS)

    Arbocz, Johann; Starnes, James H.; Nemeth, Michael P.

    2001-01-01

    The buckling strength of thin-walled stiffened or unstiffened, metallic or composite shells is of major concern in aeronautical and space applications. The difficulty to predict the behavior of axially compressed thin-walled cylindrical shells continues to worry design engineers as we enter the third millennium. Thanks to extensive research programs in the late sixties and early seventies and the contributions of many eminent scientists, it is known that buckling strength calculations are affected by the uncertainties in the definition of the parameters of the problem such as definition of loads, material properties, geometric variables, edge support conditions, and the accuracy of the engineering models and analysis tools used in the design phase. The NASA design criteria monographs from the late sixties account for these design uncertainties by the use of a lump sum safety factor. This so-called 'empirical knockdown factor gamma' usually results in overly conservative design. Recently new reliability based probabilistic design procedure for buckling critical imperfect shells have been proposed. It essentially consists of a stochastic approach which introduces an improved 'scientific knockdown factor lambda(sub a)', that is not as conservative as the traditional empirical one. In order to incorporate probabilistic methods into a High Fidelity Analysis Approach one must be able to assess the accuracy of the various steps that must be executed to complete a reliability calculation. In the present paper the effect of size of the experimental input sample on the predicted value of the scientific knockdown factor lambda(sub a) calculated by the First-Order, Second-Moment Method is investigated.

  9. Blind Prediction of Interfacial Water Positions in CAPRI

    PubMed Central

    Moal, Iain H.; Bates, Paul A.; Kastritis, Panagiotis L.; Melquiond, Adrien S.J.; Karaca, Ezgi; Schmitz, Christophe; van Dijk, Marc; Bonvin, Alexandre M.J.J.; Eisenstein, Miriam; Jiménez-García, Brian; Grosdidier, Solène; Solernou, Albert; Pérez-Cano, Laura; Pallara, Chiara; Fernández-Recio, Juan; Xu, Jianqing; Muthu, Pravin; Kilambi, Krishna Praneeth; Gray, Jeffrey J.; Grudinin, Sergei; Derevyanko, Georgy; Mitchell, Julie C.; Wieting, John; Kanamori, Eiji; Tsuchiya, Yuko; Murakami, Yoichi; Sarmiento, Joy; Standley, Daron M.; Shirota, Matsuyuki; Kinoshita, Kengo; Nakamura, Haruki; Chavent, Matthieu; Ritchie, David W.; Park, Hahnbeom; Ko, Junsu; Lee, Hasup; Seok, Chaok; Shen, Yang; Kozakov, Dima; Vajda, Sandor; Kundrotas, Petras J.; Vakser, Ilya A.; Pierce, Brian G.; Hwang, Howook; Vreven, Thom; Weng, Zhiping; Buch, Idit; Farkash, Efrat; Wolfson, Haim J.; Zacharias, Martin; Qin, Sanbo; Zhou, Huan-Xiang; Huang, Shen-You; Zou, Xiaoqin; Wojdyla, Justyna A.; Kleanthous, Colin; Wodak, Shoshana J.

    2015-01-01

    We report the first assessment of blind predictions of water positions at protein-protein interfaces, performed as part of the CAPRI (Critical Assessment of Predicted Interactions) community-wide experiment. Groups submitting docking predictions for the complex of the DNase domain of colicin E2 and Im2 immunity protein (CAPRI target 47), were invited to predict the positions of interfacial water molecules using the method of their choice. The predictions – 20 groups submitted a total of 195 models – were assessed by measuring the recall fraction of water-mediated protein contacts. Of the 176 high or medium quality docking models – a very good docking performance per se – only 44% had a recall fraction above 0.3, and a mere 6% above 0.5. The actual water positions were in general predicted to an accuracy level no better than 1.5 Å, and even in good models about half of the contacts represented false positives. This notwithstanding, three hotspot interface water positions were quite well predicted, and so was one of the water positions that is believed to stabilize the loop that confers specificity in these complexes. Overall the best interface water predictions was achieved by groups that also produced high quality docking models, indicating that accurate modelling of the protein portion is a determinant factor. The use of established molecular mechanics force fields, coupled to sampling and optimization procedures also seemed to confer an advantage. Insights gained from this analysis should help improve the prediction of protein-water interactions and their role in stabilizing protein complexes. PMID:24155158

  10. Global positioning system measurements for crustal deformation: Precision and accuracy

    USGS Publications Warehouse

    Prescott, W.H.; Davis, J.L.; Svarc, J.L.

    1989-01-01

    Analysis of 27 repeated observations of Global Positioning System (GPS) position-difference vectors, up to 11 kilometers in length, indicates that the standard deviation of the measurements is 4 millimeters for the north component, 6 millimeters for the east component, and 10 to 20 millimeters for the vertical component. The uncertainty grows slowly with increasing vector length. At 225 kilometers, the standard deviation of the measurement is 6, 11, and 40 millimeters for the north, east, and up components, respectively. Measurements with GPS and Geodolite, an electromagnetic distance-measuring system, over distances of 10 to 40 kilometers agree within 0.2 part per million. Measurements with GPS and very long baseline interferometry of the 225-kilometer vector agree within 0.05 part per million.

  11. General Theory versus ENA Theory: Comparing Their Predictive Accuracy and Scope.

    PubMed

    Ellis, Lee; Hoskin, Anthony; Hartley, Richard; Walsh, Anthony; Widmayer, Alan; Ratnasingam, Malini

    2015-12-01

    General theory attributes criminal behavior primarily to low self-control, whereas evolutionary neuroandrogenic (ENA) theory envisions criminality as being a crude form of status-striving promoted by high brain exposure to androgens. General theory predicts that self-control will be negatively correlated with risk-taking, while ENA theory implies that these two variables should actually be positively correlated. According to ENA theory, traits such as pain tolerance and muscularity will be positively associated with risk-taking and criminality while general theory makes no predictions concerning these relationships. Data from Malaysia and the United States are used to test 10 hypotheses derived from one or both of these theories. As predicted by both theories, risk-taking was positively correlated with criminality in both countries. However, contrary to general theory and consistent with ENA theory, the correlation between self-control and risk-taking was positive in both countries. General theory's prediction of an inverse correlation between low self-control and criminality was largely supported by the U.S. data but only weakly supported by the Malaysian data. ENA theory's predictions of positive correlations between pain tolerance, muscularity, and offending were largely confirmed. For the 10 hypotheses tested, ENA theory surpassed general theory in predictive scope and accuracy.

  12. Predicting Positive and Negative Relationships in Large Social Networks.

    PubMed

    Wang, Guan-Nan; Gao, Hui; Chen, Lian; Mensah, Dennis N A; Fu, Yan

    2015-01-01

    In a social network, users hold and express positive and negative attitudes (e.g. support/opposition) towards other users. Those attitudes exhibit some kind of binary relationships among the users, which play an important role in social network analysis. However, some of those binary relationships are likely to be latent as the scale of social network increases. The essence of predicting latent binary relationships have recently began to draw researchers' attention. In this paper, we propose a machine learning algorithm for predicting positive and negative relationships in social networks inspired by structural balance theory and social status theory. More specifically, we show that when two users in the network have fewer common neighbors, the prediction accuracy of the relationship between them deteriorates. Accordingly, in the training phase, we propose a segment-based training framework to divide the training data into two subsets according to the number of common neighbors between users, and build a prediction model for each subset based on support vector machine (SVM). Moreover, to deal with large-scale social network data, we employ a sampling strategy that selects small amount of training data while maintaining high accuracy of prediction. We compare our algorithm with traditional algorithms and adaptive boosting of them. Experimental results of typical data sets show that our algorithm can deal with large social networks and consistently outperforms other methods.

  13. Predicting Positive and Negative Relationships in Large Social Networks

    PubMed Central

    Wang, Guan-Nan; Gao, Hui; Chen, Lian; Mensah, Dennis N. A.; Fu, Yan

    2015-01-01

    In a social network, users hold and express positive and negative attitudes (e.g. support/opposition) towards other users. Those attitudes exhibit some kind of binary relationships among the users, which play an important role in social network analysis. However, some of those binary relationships are likely to be latent as the scale of social network increases. The essence of predicting latent binary relationships have recently began to draw researchers' attention. In this paper, we propose a machine learning algorithm for predicting positive and negative relationships in social networks inspired by structural balance theory and social status theory. More specifically, we show that when two users in the network have fewer common neighbors, the prediction accuracy of the relationship between them deteriorates. Accordingly, in the training phase, we propose a segment-based training framework to divide the training data into two subsets according to the number of common neighbors between users, and build a prediction model for each subset based on support vector machine (SVM). Moreover, to deal with large-scale social network data, we employ a sampling strategy that selects small amount of training data while maintaining high accuracy of prediction. We compare our algorithm with traditional algorithms and adaptive boosting of them. Experimental results of typical data sets show that our algorithm can deal with large social networks and consistently outperforms other methods. PMID:26075404

  14. Accuracy of cervicovaginal fetal fibronectin test in predicting risk of spontaneous preterm birth: systematic review

    PubMed Central

    Honest, Honest; Bachmann, Lucas M; Gupta, Janesh K; Kleijnen, Jos; Khan, Khalid S

    2002-01-01

    Objective To determine the accuracy with which a cervicovaginal fetal fibronectin test predicts spontaneous preterm birth in women with or without symptoms of preterm labour. Design Systematic quantitative review of studies of test accuracy. Data sources Medline, Embase, PASCAL, Biosis, Cochrane Library, Medion, National Research Register, SCISEARCH, conference papers, manual searching of bibliographies of known primary and review articles, and contact with experts and manufacturer. Study selection Two reviewers independently selected and extracted data on study characteristics, quality, and accuracy. Data extraction Accuracy data were used to form 2×2 contingency tables with spontaneous preterm birth before 34 and 37 weeks' gestation and birth within 7-10 days of testing (for symptomatic pregnant women) as reference standards. Data were pooled to produce summary receiver operating characteristic curves and summary likelihood ratios for positive and negative test results. Data synthesis 64 primary articles were identified, consisting of 28 studies in asymptomatic women and 40 in symptomatic women, with a total of 26 876 women. Among asymptomatic women the best summary likelihood ratio for positive results was 4.01 (95% confidence interval 2.93 to 5.49) for predicting birth before 34 weeks' gestation, with corresponding summary likelihood ratio for negative results of 0.78 (0.72 to 0.84). Among symptomatic women the best summary likelihood ratio for positive results was 5.42 (4.36 to 6.74) for predicting birth within 7-10 days of testing, with corresponding ratio for negative results of 0.25 (0.20 to 0.31). Conclusion Cervicovaginal fetal fibronectin test is most accurate in predicting spontaneous preterm birth within 7-10 days of testing among women with symptoms of threatened preterm birth before advanced cervical dilatation. What is already known on this topicSpontaneous preterm birth is a major cause of neonatal morbidity and mortalityIf spontaneous preterm

  15. Prediction Accuracy: The Role of Feedback in 6th Graders' Recall Predictions

    ERIC Educational Resources Information Center

    Al-Harthy, Ibrahim S.

    2016-01-01

    The current study focused on the role of feedback on students' prediction accuracy (calibration). This phenomenon has been widely studied, but questions remain about how best to improve it. In the current investigation, fifty-seven students from sixth grade were randomly assigned to control and experimental groups. Thirty pictures were chosen from…

  16. Accuracy aspects of recent laser station positioning experiments

    NASA Astrophysics Data System (ADS)

    Ambrosius, B. A. C.; Noomen, R.; Wakker, K. F.; Papazissi, E.

    1987-12-01

    Over the past few years, the contribution of the European laser ranging systems to the total amount of global observations of the LAGEOS geodynamics satellite has increased considerably. In the studies described in this paper selected samples of the data are used to derive the positions of the European stations within the framework of a global coordinates solution and to determine accurate baselines between these stations. Recent improvements in the dynamic models of the motion of the earth and LAGEOS, and the high quality of the laser data, are shown to result in monthly global coordinate solutions with a consistency of better than 5 cm. The repeatability of monthly solutions of the European baselines is demonstrated to be even better than 3.5 cm. A combined global station coordinate solution is presented, based on the tracking data of the first three months of 1986 and denoted by DUT/SOM LSC 87.1. Also the effects of tectonic plate motions are shown to be detectable from the analysis of data covering a period of less than 2 years. The results for the baseline from Monument Peak to Quincy, which crosses the San Andreas fault, are highlighted.

  17. Social anxiety and the accuracy of predicted affect.

    PubMed

    Martin, Shannon M; Quirk, Stuart W

    2015-01-01

    Social anxiety is theorised to arise from sustained over-activation of a mammalian evolved system for detecting and responding to social threat with corresponding diminished opportunities for attaining the pleasure of safe attachments. Emotional forecasting data from two holidays were used to test the hypothesis that greater social anxiety would be associated with decreased expectations of positive affect (PA) and greater anticipated negative affect (NA) on a holiday marked by group celebration (St. Patrick's Day) while being associated with greater predicted PA for daters on a romantic holiday (Valentine's Day). Participants completed symptom reports, made affective forecasts and provided multiple affect reports throughout each holiday. Higher levels of social anxiety were associated with greater anticipated PA for Valentine's Day daters, but lower experienced PA on the holiday; this was not found for trait anxiety and depression. Alternatively, trait anxiety, depression and social anxiety were associated with less predicted PA for St. Patrick's Day, greater anticipated NA and diminished experienced PA/greater NA during the holiday. Results are discussed in light of perceived hope for rewarding safe emotional contact for those daters in contrast to the greater possibility for social threat associated with group celebration typical of St. Patrick's Day.

  18. High-accuracy indoor positioning system based on visible light communication

    NASA Astrophysics Data System (ADS)

    Wei, Ling; Zhang, Hongming; Yu, Bingyan; Guan, Yang

    2015-11-01

    A visible light communication (VLC)-based high-accuracy indoor positioning system is proposed and demonstrated. In this system, the light-emitting diode identification (LED-ID) indicating the position information of the LED can be transmitted to the receiver by the illumination LED through VLC. In the meantime, with the aid of a camera and angular sensors of the mobile device, a coordinate transform can be employed to calculate the relative position between the receiver and the reference LED so that the position of the receiver can be determined. Finally, the experimental results show that 2-cm positioning accuracy can be achieved and the simulation results indicate that the positioning error can be limited within 4.7 cm when the accuracy of angular sensors is 1 deg.

  19. Systematic bias of correlation coefficient may explain negative accuracy of genomic prediction.

    PubMed

    Zhou, Yao; Isabel Vales, M; Wang, Aoxue; Zhang, Zhiwu

    2016-07-19

    Accuracy of genomic prediction is commonly calculated as the Pearson correlation coefficient between the predicted and observed phenotypes in the inference population by using cross-validation analysis. More frequently than expected, significant negative accuracies of genomic prediction have been reported in genomic selection studies. These negative values are surprising, given that the minimum value for prediction accuracy should hover around zero when randomly permuted data sets are analyzed. We reviewed the two common approaches for calculating the Pearson correlation and hypothesized that these negative accuracy values reflect potential bias owing to artifacts caused by the mathematical formulas used to calculate prediction accuracy. The first approach, Instant accuracy, calculates correlations for each fold and reports prediction accuracy as the mean of correlations across fold. The other approach, Hold accuracy, predicts all phenotypes in all fold and calculates correlation between the observed and predicted phenotypes at the end of the cross-validation process. Using simulated and real data, we demonstrated that our hypothesis is true. Both approaches are biased downward under certain conditions. The biases become larger when more fold are employed and when the expected accuracy is low. The bias of Instant accuracy can be corrected using a modified formula.

  20. Accuracy of Linear Measurements of Galileos Cone Beam Computed Tomography in Normal and Different Head Positions

    PubMed Central

    Sheikhi, Mahnaz; Ghorbanizadeh, Sajad; Abdinian, Mehrdad; Goroohi, Hossein; Badrian, Hamid

    2012-01-01

    Introduction. The aim of this study was to determine the accuracy of linear measurements in dry human skulls in ideal position and different deviated positions of the skull. Methods. 6 dry human skulls were included in the study. Opaque markers were attached to alveolar bone. Buccolingual and mesiodistal distances and heights were measured in 5 different regions of either jaws using a digital caliper. Radiographic distances were measured in ideal, rotation, tilt, flexion, and extension positions of the skulls. The physical and radiographic measurements were compared to estimate linear measurement accuracy. Results. The mean difference between physical measurements and radiographic measurements was 0.05 ± 0.45. There was a significant difference between physical measurements and radiographic measurements in ideal, rotation, tilt, and extension positions (P   value < 0.05). Conclusions. The accuracy of measurements in GALILEOUS CBCT machine varies when the position of the skull deviates from ideal; however, the differences are not clinically significant. PMID:22844282

  1. Predictability of maxillary repositioning during bimaxillary surgery: accuracy of a new technique.

    PubMed

    Gil, J N; Claus, J D P; Manfro, R; Lima, S M

    2007-04-01

    The purpose of this retrospective study was to evaluate the predictability of maxillary repositioning following Le Fort I osteotomy during bimaxillary surgery using a new technique with splints to reposition the maxilla in the three planes of space. In order to assess the accuracy of horizontal and vertical maxillary movements of the maxilla, 32 consecutive patients who underwent bimaxillary surgery had their predictive tracings and model surgery measures compared to postoperative cephalograms taken 1 week after surgery. There was a strong positive correlation between model surgery and postoperative result: 53% of horizontal movements and 41% of vertical movements showed less than 0.2 mm variation. When predictive tracings were compared to postoperative results 44% of horizontal and 50% of vertical movements showed less than 0.2 mm variation. There was no significant difference (P>0.05) between the planned and actual maxillary positions in the sample evaluated. This technique for maxillary repositioning during two-jaw surgery proved to be effective and predictable, with strong agreement between predictive tracings, model surgery and postoperative results.

  2. A phantom study on the positioning accuracy of the Novalis Body system.

    PubMed

    Yan, Hui; Yin, Fang-Fang; Kim, Jae Ho

    2003-12-01

    A phantom study was conducted to investigate inherent positioning accuracy of an image-guided patient positioning system-the Novalis Body system for three-dimensional (3-D) conformal radiotherapy. This positioning system consists of two infrared (IR) cameras and one video camera and two kV x-ray imaging devices. The initial patient setup was guided by the IR camera system and the target localization was accomplished using the kV x-ray imaging system. In this study, the IR marker shift and phantom rotation were simulated and their effects on the positioning accuracy were examined by a Rando phantom. The effects of CT slice thickness and treatment sites on the positioning accuracy were tested. In addition, the internal target shift was simulated and its effect on the positioning accuracy was examined by a water tank. With the application of the Novalis Body system, the positioning error of the planned isocenter was significantly reduced. The experimental results with the simulated IR marker shifts indicated that the positioning errors of the planned isocenter were 0.6 +/- 0.3, 0.5 +/- 0.2, and 0.7 +/- 0.2 mm along the lateral, longitudinal, and vertical axes, respectively. The experimental results with the simulated phantom rotations indicated that the positioning errors of the planned isocenter were 0.6 +/- 0.3, 0.7 +/- 0.2, and 0.5 +/- 0.2 mm along the three axes, respectively. The experimental results with the simulated target shifts indicated that the positioning errors of the planned isocenter were 0.6 +/- 0.3, 0.7 +/- 0.2, and 0.5 +/- 0.2 mm along the three axes, respectively. On average, the positioning accuracy of 1 mm for the planned isocenter was achieved using the Novalis Body system.

  3. Changes in Memory Prediction Accuracy: Age and Performance Effects

    ERIC Educational Resources Information Center

    Pearman, Ann; Trujillo, Amanda

    2013-01-01

    Memory performance predictions are subjective estimates of possible memory task performance. The purpose of this study was to examine possible factors related to changes in word list performance predictions made by younger and older adults. Factors included memory self-efficacy, actual performance, and perceptions of performance. The current study…

  4. Accuracy and stability of positioning in radiosurgery: Long term results of the Gamma Knife system

    SciTech Connect

    Heck, Bernhard; Jess-Hempen, Anja; Kreiner, Hans Juerg; Schoepgens, Hans; Mack, Andreas

    2007-04-15

    The primary aim of this investigation was to determine the long term overall accuracy of an irradiation position of Gamma Knife systems. The mechanical accuracy of the system as well as the overall accuracy of an irradiation position was examined by irradiating radiosensitive films. To measure the mechanical accuracy, the GafChromic registered film was fixed by a special tool at the unit center point (UCP). For overall accuracy the film was mounted inside a phantom at a target position given by a two-dimensional cross. Its position was determined by CT or MRI scans, a treatment was planned to hit this target by use of the standard planning software and the radiation was finally delivered. This procedure is named ''system test'' according to DIN 6875-1 and is equivalent to a treatment simulation. The used GafChromic registered films were evaluated by high resolution densitometric measurements. The Munich Gamma Knife UCP coincided within x;y;z: -0.014{+-}0.09 mm; 0.013{+-}0.09 mm; -0.002{+-}0.06 mm (mean{+-}SD) to the center of dose distribution. There was no trend in the measured data observed over more than ten years. All measured data were within a sphere of 0.2 mm radius. When basing the target definition in the system test on MRI scans, we obtained an overall accuracy of an irradiation position in the x direction of 0.21{+-}0.32 mm and in the y direction 0.15{+-}0.26 mm (mean{+-}SD). When a CT-based target definition was used, we measured distances in x direction 0.06{+-}0.09 mm and in y direction 0.04{+-}0.09 mm (mean{+-}SD), respectively. These results were compared with those obtained with a Gamma Knife equipped with an automatic positioning system (APS) by use of a different phantom. This phantom was found to be slightly less accurate due to its mechanical construction and the soft fixation into the frame. The phantom related position deviation was found to be about {+-}0.2 mm, and therefore the measured accuracy of the APS Gamma Knife was evidently less

  5. Positioning accuracy assessment for the 4GEO/5IGSO/2MEO constellation of COMPASS

    NASA Astrophysics Data System (ADS)

    Zhou, ShanShi; Cao, YueLing; Zhou, JianHua; Hu, XiaoGong; Tang, ChengPan; Liu, Li; Guo, Rui; He, Feng; Chen, JunPing; Wu, Bin

    2012-12-01

    Determined to become a new member of the well-established GNSS family, COMPASS (or BeiDou-2) is developing its capabilities to provide high accuracy positioning services. Two positioning modes are investigated in this study to assess the positioning accuracy of COMPASS' 4GEO/5IGSO/2MEO constellation. Precise Point Positioning (PPP) for geodetic users and real-time positioning for common navigation users are utilized. To evaluate PPP accuracy, coordinate time series repeatability and discrepancies with GPS' precise positioning are computed. Experiments show that COMPASS PPP repeatability for the east, north and up components of a receiver within mainland China is better than 2 cm, 2 cm and 5 cm, respectively. Apparent systematic offsets of several centimeters exist between COMPASS precise positioning and GPS precise positioning, indicating errors remaining in the treatments of COMPASS measurement and dynamic models and reference frame differences existing between two systems. For common positioning users, COMPASS provides both open and authorized services with rapid differential corrections and integrity information available to authorized users. Our assessment shows that in open service positioning accuracy of dual-frequency and single-frequency users is about 5 m and 6 m (RMS), respectively, which may be improved to about 3 m and 4 m (RMS) with the addition of differential corrections. Less accurate Signal In Space User Ranging Error (SIS URE) and Geometric Dilution of Precision (GDOP) contribute to the relatively inferior accuracy of COMPASS as compared to GPS. Since the deployment of the remaining 1 GEO and 2 MEO is not able to significantly improve GDOP, the performance gap could only be overcome either by the use of differential corrections or improvement of the SIS URE, or both.

  6. Accuracy of BRCA1/2 mutation prediction models in Korean breast cancer patients.

    PubMed

    Kang, Eunyoung; Park, Sue K; Yang, Jae Jeong; Park, Boyoung; Lee, Min Hyuk; Lee, Jong Won; Suh, Young Jin; Lee, Jeong Eon; Kim, Hyun-Ah; Oh, Se Jeong; Kim, Sung-Won

    2012-08-01

    BRCAPRO and Myriad II are widely used models for predicting BRCA1/2 mutation probability before genetic testing. However, the accuracy of these models in Koreans is not known. This study was performed to evaluate the accuracy of the BRCAPRO and Myriad II models. Two hundred thirty-six women with breast cancer who underwent comprehensive BRCA1/2 genetic testing at our hospital between 2003 and 2010 were included in this study. We evaluated the performance of each model by comparing the numbers of observed versus predicted mutation carriers. We calculated sensitivity, specificity, and predictive values at 10 % estimated probability. Forty-six individuals were identified to carry a deleterious BRCA mutation. The prevalence of BRCA mutation (19.5 %) was significantly higher than that predicted by BRCAPRO (9.0 %, p = 0.001) and Myriad (5.6 %, p < 0.001). In familial breast cancer patients, BRCA mutation rate (observed 22.7 %) was underestimated by both BRCAPRO (expected 11.4 %, p = 0.006) and Myriad II (expected 6.4 %, p < 0.001). Subgroup analyses showed that both models underestimated the risk of BRCA mutation in patients with a family history of breast cancer (probands' age at breast cancer diagnosis >50 years), with only one relative with breast cancer, and with non-familial early-onset breast cancer or bilateral breast cancer. Using a 10 % cut-off, the sensitivities were 47.8 % (BRCAPRO) and 50.0 % (Myriad), and positive predictive values were 44.9 % (BRCAPRO) and 43.4 % (Myriad). Both BRCAPRO and Myriad II underestimated the risk of BRCA1/2 mutation in Koreans. Our findings suggest that these models are less sensitive in Korean women, and therefore a new BRCA mutation prediction model based on Korean data is needed for proper genetic counseling.

  7. Combined adjustment of multi-resolution satellite imagery for improved geo-positioning accuracy

    NASA Astrophysics Data System (ADS)

    Tang, Shengjun; Wu, Bo; Zhu, Qing

    2016-04-01

    Due to the widespread availability of satellite imagery nowadays, it is common for regions to be covered by satellite imagery from multiple sources with multiple resolutions. This paper presents a combined adjustment approach to integrate multi-source multi-resolution satellite imagery for improved geo-positioning accuracy without the use of ground control points (GCPs). Instead of using all the rational polynomial coefficients (RPCs) of images for processing, only those dominating the geo-positioning accuracy are used in the combined adjustment. They, together with tie points identified in the images, are used as observations in the adjustment model. Proper weights are determined for each observation, and ridge parameters are determined for better convergence of the adjustment solution. The outputs from the combined adjustment are the improved dominating RPCs of images, from which improved geo-positioning accuracy can be obtained. Experiments using ZY-3, SPOT-7 and Pleiades-1 imagery in Hong Kong, and Cartosat-1 and Worldview-1 imagery in Catalonia, Spain demonstrate that the proposed method is able to effectively improve the geo-positioning accuracy of satellite images. The combined adjustment approach offers an alternative method to improve geo-positioning accuracy of satellite images. The approach enables the integration of multi-source and multi-resolution satellite imagery for generating more precise and consistent 3D spatial information, which permits the comparative and synergistic use of multi-resolution satellite images from multiple sources.

  8. A Comparative Study of Precise Point Positioning (PPP) Accuracy Using Online Services

    NASA Astrophysics Data System (ADS)

    Malinowski, Marcin; Kwiecień, Janusz

    2016-12-01

    Precise Point Positioning (PPP) is a technique used to determine the position of receiver antenna without communication with the reference station. It may be an alternative solution to differential measurements, where maintaining a connection with a single RTK station or a regional network of reference stations RTN is necessary. This situation is especially common in areas with poorly developed infrastructure of ground stations. A lot of research conducted so far on the use of the PPP technique has been concerned about the development of entire day observation sessions. However, this paper presents the results of a comparative analysis of accuracy of absolute determination of position from observations which last between 1 to 7 hours with the use of four permanent services which execute calculations with PPP technique such as: Automatic Precise Positioning Service (APPS), Canadian Spatial Reference System Precise Point Positioning (CSRS-PPP), GNSS Analysis and Positioning Software (GAPS) and magicPPP - Precise Point Positioning Solution (magicGNSS). On the basis of acquired results of measurements, it can be concluded that at least two-hour long measurements allow acquiring an absolute position with an accuracy of 2-4 cm. An evaluation of the impact on the accuracy of simultaneous positioning of three points test network on the change of the horizontal distance and the relative height difference between measured triangle vertices was also conducted. Distances and relative height differences between points of the triangular test network measured with a laser station Leica TDRA6000 were adopted as references. The analyses of results show that at least two hours long measurement sessions can be used to determine the horizontal distance or the difference in height with an accuracy of 1-2 cm. Rapid products employed in calculations conducted with PPP technique reached the accuracy of determining coordinates on a close level as in elaborations which employ Final products.

  9. The Positioning Accuracy of BAUV Using Fusion of Data from USBL System and Movement Parameters Measurements.

    PubMed

    Krzysztof, Naus; Aleksander, Nowak

    2016-08-15

    The article presents a study of the accuracy of estimating the position coordinates of BAUV (Biomimetic Autonomous Underwater Vehicle) by the extended Kalman filter (EKF) method. The fusion of movement parameters measurements and position coordinates fixes was applied. The movement parameters measurements are carried out by on-board navigation devices, while the position coordinates fixes are done by the USBL (Ultra Short Base Line) system. The problem of underwater positioning and the conceptual design of the BAUV navigation system constructed at the Naval Academy (Polish Naval Academy-PNA) are presented in the first part of the paper. The second part consists of description of the evaluation results of positioning accuracy, the genesis of the problem of selecting method for underwater positioning, and the mathematical description of the method of estimating the position coordinates using the EKF method by the fusion of measurements with on-board navigation and measurements obtained with the USBL system. The main part contains a description of experimental research. It consists of a simulation program of navigational parameter measurements carried out during the BAUV passage along the test section. Next, the article covers the determination of position coordinates on the basis of simulated parameters, using EKF and DR methods and the USBL system, which are then subjected to a comparative analysis of accuracy. The final part contains systemic conclusions justifying the desirability of applying the proposed fusion method of navigation parameters for the BAUV positioning.

  10. The Positioning Accuracy of BAUV Using Fusion of Data from USBL System and Movement Parameters Measurements

    PubMed Central

    Krzysztof, Naus; Aleksander, Nowak

    2016-01-01

    The article presents a study of the accuracy of estimating the position coordinates of BAUV (Biomimetic Autonomous Underwater Vehicle) by the extended Kalman filter (EKF) method. The fusion of movement parameters measurements and position coordinates fixes was applied. The movement parameters measurements are carried out by on-board navigation devices, while the position coordinates fixes are done by the USBL (Ultra Short Base Line) system. The problem of underwater positioning and the conceptual design of the BAUV navigation system constructed at the Naval Academy (Polish Naval Academy—PNA) are presented in the first part of the paper. The second part consists of description of the evaluation results of positioning accuracy, the genesis of the problem of selecting method for underwater positioning, and the mathematical description of the method of estimating the position coordinates using the EKF method by the fusion of measurements with on-board navigation and measurements obtained with the USBL system. The main part contains a description of experimental research. It consists of a simulation program of navigational parameter measurements carried out during the BAUV passage along the test section. Next, the article covers the determination of position coordinates on the basis of simulated parameters, using EKF and DR methods and the USBL system, which are then subjected to a comparative analysis of accuracy. The final part contains systemic conclusions justifying the desirability of applying the proposed fusion method of navigation parameters for the BAUV positioning. PMID:27537884

  11. Initial eyewitness confidence reliably predicts eyewitness identification accuracy.

    PubMed

    Wixted, John T; Mickes, Laura; Clark, Steven E; Gronlund, Scott D; Roediger, Henry L

    2015-09-01

    Eyewitness memory is widely believed to be unreliable because (a) high-confidence eyewitness misidentifications played a role in over 70% of the now more than 300 DNA exonerations of wrongfully convicted men and women, (b) forensically relevant laboratory studies have often reported a weak relationship between eyewitness confidence and accuracy, and (c) memory is sufficiently malleable that, not infrequently, people (including eyewitnesses) can be led to remember events differently from the way the events actually happened. In light of such evidence, many researchers agree that confidence statements made by eyewitnesses in a court of law (in particular, the high confidence they often express at trial) should be discounted, if not disregarded altogether. But what about confidence statements made by eyewitnesses at the time of the initial identification (e.g., from a lineup), before there is much opportunity for memory contamination to occur? A considerable body of recent empirical work suggests that confidence may be a highly reliable indicator of accuracy at that time, which fits with longstanding theoretical models of recognition memory. Counterintuitively, an appreciation of this fact could do more to protect innocent defendants from being wrongfully convicted than any other eyewitness identification reform that has been proposed to date.

  12. Positional Accuracy of Airborne Integrated Global Positioning and Inertial Navigation Systems for Mapping in Glen Canyon, Arizona

    USGS Publications Warehouse

    Sanchez, Richard D.; Hothem, Larry D.

    2002-01-01

    High-resolution airborne and satellite image sensor systems integrated with onboard data collection based on the Global Positioning System (GPS) and inertial navigation systems (INS) may offer a quick and cost-effective way to gather accurate topographic map information without ground control or aerial triangulation. The Applanix Corporation?s Position and Orientation Solutions for Direct Georeferencing of aerial photography was used in this project to examine the positional accuracy of integrated GPS/INS for terrain mapping in Glen Canyon, Arizona. The research application in this study yielded important information on the usefulness and limits of airborne integrated GPS/INS data-capture systems for mapping.

  13. Improving the accuracy of protein stability predictions with multistate design using a variety of backbone ensembles.

    PubMed

    Davey, James A; Chica, Roberto A

    2014-05-01

    Multistate computational protein design (MSD) with backbone ensembles approximating conformational flexibility can predict higher quality sequences than single-state design with a single fixed backbone. However, it is currently unclear what characteristics of backbone ensembles are required for the accurate prediction of protein sequence stability. In this study, we aimed to improve the accuracy of protein stability predictions made with MSD by using a variety of backbone ensembles to recapitulate the experimentally measured stability of 85 Streptococcal protein G domain β1 sequences. Ensembles tested here include an NMR ensemble as well as those generated by molecular dynamics (MD) simulations, by Backrub motions, and by PertMin, a new method that we developed involving the perturbation of atomic coordinates followed by energy minimization. MSD with the PertMin ensembles resulted in the most accurate predictions by providing the highest number of stable sequences in the top 25, and by correctly binning sequences as stable or unstable with the highest success rate (≈90%) and the lowest number of false positives. The performance of PertMin ensembles is due to the fact that their members closely resemble the input crystal structure and have low potential energy. Conversely, the NMR ensemble as well as those generated by MD simulations at 500 or 1000 K reduced prediction accuracy due to their low structural similarity to the crystal structure. The ensembles tested herein thus represent on- or off-target models of the native protein fold and could be used in future studies to design for desired properties other than stability.

  14. An Effective Approach to Improving Low-Cost GPS Positioning Accuracy in Real-Time Navigation

    PubMed Central

    Islam, Md. Rashedul; Kim, Jong-Myon

    2014-01-01

    Positioning accuracy is a challenging issue for location-based applications using a low-cost global positioning system (GPS). This paper presents an effective approach to improving the positioning accuracy of a low-cost GPS receiver for real-time navigation. The proposed method precisely estimates position by combining vehicle movement direction, velocity averaging, and distance between waypoints using coordinate data (latitude, longitude, time, and velocity) of the GPS receiver. The previously estimated precious reference point, coordinate translation, and invalid data check also improve accuracy. In order to evaluate the performance of the proposed method, we conducted an experiment using a GARMIN GPS 19xHVS receiver attached to a car and used Google Maps to plot the processed data. The proposed method achieved improvement of 4–10 meters in several experiments. In addition, we compared the proposed approach with two other state-of-the-art methods: recursive averaging and ARMA interpolation. The experimental results show that the proposed approach outperforms other state-of-the-art methods in terms of positioning accuracy. PMID:25136679

  15. Predictive accuracy of risk scales following self-harm: multicentre, prospective cohort study.

    PubMed

    Quinlivan, Leah; Cooper, Jayne; Meehan, Declan; Longson, Damien; Potokar, John; Hulme, Tom; Marsden, Jennifer; Brand, Fiona; Lange, Kezia; Riseborough, Elena; Page, Lisa; Metcalfe, Chris; Davies, Linda; O'Connor, Rory; Hawton, Keith; Gunnell, David; Kapur, Nav

    2017-03-16

    BackgroundScales are widely used in psychiatric assessments following self-harm. Robust evidence for their diagnostic use is lacking.AimsTo evaluate the performance of risk scales (Manchester Self-Harm Rule, ReACT Self-Harm Rule, SAD PERSONS scale, Modified SAD PERSONS scale, Barratt Impulsiveness Scale); and patient and clinician estimates of risk in identifying patients who repeat self-harm within 6 months.MethodA multisite prospective cohort study was conducted of adults aged 18 years and over referred to liaison psychiatry services following self-harm. Scale a priori cut-offs were evaluated using diagnostic accuracy statistics. The area under the curve (AUC) was used to determine optimal cut-offs and compare global accuracy.ResultsIn total, 483 episodes of self-harm were included in the study. The episode-based 6-month repetition rate was 30% (n = 145). Sensitivity ranged from 1% (95% CI 0-5) for the SAD PERSONS scale, to 97% (95% CI 93-99) for the Manchester Self-Harm Rule. Positive predictive values ranged from 13% (95% CI 2-47) for the Modified SAD PERSONS Scale to 47% (95% CI 41-53) for the clinician assessment of risk. The AUC ranged from 0.55 (95% CI 0.50-0.61) for the SAD PERSONS scale to 0.74 (95% CI 0.69-0.79) for the clinician global scale. The remaining scales performed significantly worse than clinician and patient estimates of risk (P<0.001).ConclusionsRisk scales following self-harm have limited clinical utility and may waste valuable resources. Most scales performed no better than clinician or patient ratings of risk. Some performed considerably worse. Positive predictive values were modest. In line with national guidelines, risk scales should not be used to determine patient management or predict self-harm.

  16. The effect of different Global Navigation Satellite System methods on positioning accuracy in elite alpine skiing.

    PubMed

    Gilgien, Matthias; Spörri, Jörg; Limpach, Philippe; Geiger, Alain; Müller, Erich

    2014-10-03

    In sport science, Global Navigation Satellite Systems (GNSS) are frequently applied to capture athletes' position, velocity and acceleration. Application of GNSS includes a large range of different GNSS technologies and methods. To date no study has comprehensively compared the different GNSS methods applied. Therefore, the aim of the current study was to investigate the effect of differential and non-differential solutions, different satellite systems and different GNSS signal frequencies on position accuracy. Twelve alpine ski racers were equipped with high-end GNSS devices while performing runs on a giant slalom course. The skiers' GNSS antenna positions were calculated in three satellite signal obstruction conditions using five different GNSS methods. The GNSS antenna positions were compared to a video-based photogrammetric reference system over one turn and against the most valid GNSS method over the entire run. Furthermore, the time for acquisitioning differential GNSS solutions was assessed for four differential methods. The only GNSS method that consistently yielded sub-decimetre position accuracy in typical alpine skiing conditions was a differential method using American (GPS) and Russian (GLONASS) satellite systems and the satellite signal frequencies L1 and L2. Under conditions of minimal satellite signal obstruction, valid results were also achieved when either the satellite system GLONASS or the frequency L2 was dropped from the best configuration. All other methods failed to fulfill the accuracy requirements needed to detect relevant differences in the kinematics of alpine skiers, even in conditions favorable for GNSS measurements. The methods with good positioning accuracy had also the shortest times to compute differential solutions. This paper highlights the importance to choose appropriate methods to meet the accuracy requirements for sport applications.

  17. The Effect of Different Global Navigation Satellite System Methods on Positioning Accuracy in Elite Alpine Skiing

    PubMed Central

    Gilgien, Matthias; Spörri, Jörg; Limpach, Philippe; Geiger, Alain; Müller, Erich

    2014-01-01

    In sport science, Global Navigation Satellite Systems (GNSS) are frequently applied to capture athletes' position, velocity and acceleration. Application of GNSS includes a large range of different GNSS technologies and methods. To date no study has comprehensively compared the different GNSS methods applied. Therefore, the aim of the current study was to investigate the effect of differential and non-differential solutions, different satellite systems and different GNSS signal frequencies on position accuracy. Twelve alpine ski racers were equipped with high-end GNSS devices while performing runs on a giant slalom course. The skiers' GNSS antenna positions were calculated in three satellite signal obstruction conditions using five different GNSS methods. The GNSS antenna positions were compared to a video-based photogrammetric reference system over one turn and against the most valid GNSS method over the entire run. Furthermore, the time for acquisitioning differential GNSS solutions was assessed for four differential methods. The only GNSS method that consistently yielded sub-decimetre position accuracy in typical alpine skiing conditions was a differential method using American (GPS) and Russian (GLONASS) satellite systems and the satellite signal frequencies L1 and L2. Under conditions of minimal satellite signal obstruction, valid results were also achieved when either the satellite system GLONASS or the frequency L2 was dropped from the best configuration. All other methods failed to fulfill the accuracy requirements needed to detect relevant differences in the kinematics of alpine skiers, even in conditions favorable for GNSS measurements. The methods with good positioning accuracy had also the shortest times to compute differential solutions. This paper highlights the importance to choose appropriate methods to meet the accuracy requirements for sport applications. PMID:25285461

  18. Accuracy of velocities from repeated GPS surveys: relative positioning is concerned

    NASA Astrophysics Data System (ADS)

    Duman, Huseyin; Ugur Sanli, D.

    2016-04-01

    Over more than a decade, researchers have been interested in studying the accuracy of GPS positioning solutions. Recently, reporting the accuracy of GPS velocities has been added to this. Researchers studying landslide motion, tectonic motion, uplift, sea level rise, and subsidence still report results from GPS experiments in which repeated GPS measurements from short sessions are used. This motivated some other researchers to study the accuracy of GPS deformation rates/velocities from various repeated GPS surveys. In one of the efforts, the velocity accuracy was derived from repeated GPS static surveys using short observation sessions and Precise Point Positioning mode of GPS software. Velocities from short GPS sessions were compared with the velocities from 24 h sessions. The accuracy of velocities was obtained using statistical hypothesis testing and quantifying the accuracy of least squares estimation models. The results reveal that 45-60 % of the horizontal and none of the vertical solutions comply with the results from 24 h solutions. We argue that this case in which the data was evaluated using PPP should also apply to the case in which the data belonging to long GPS base lengths is processed using fundamental relative point positioning. To test this idea we chose the two IGS stations ANKR and NICO and derive their velocities from the reference stations held fixed in the stable EURASIAN plate. The University of Bern's GNSS software BERNESE was used to produce relative positioning solutions, and the results are compared with those of GIPSY/OASIS II PPP results. First impressions indicate that it is worth designing a global experiment and test these ideas in detail.

  19. Horizontal Positional Accuracy of Google Earth's High-Resolution Imagery Archive.

    PubMed

    Potere, David

    2008-12-08

    Google Earth now hosts high-resolution imagery that spans twenty percent of the Earth's landmass and more than a third of the human population. This contemporary highresolution archive represents a significant, rapidly expanding, cost-free and largely unexploited resource for scientific inquiry. To increase the scientific utility of this archive, we address horizontal positional accuracy (georegistration) by comparing Google Earth with Landsat GeoCover scenes over a global sample of 436 control points located in 109 cities worldwide. Landsat GeoCover is an orthorectified product with known absolute positional accuracy of less than 50 meters root-mean-squared error (RMSE). Relative to Landsat GeoCover, the 436 Google Earth control points have a positional accuracy of 39.7 meters RMSE (error magnitudes range from 0.4 to 171.6 meters). The control points derived from satellite imagery have an accuracy of 22.8 meters RMSE, which is significantly more accurate than the 48 control-points based on aerial photography (41.3 meters RMSE; t-test p-value < 0.01). The accuracy of control points in more-developed countries is 24.1 meters RMSE, which is significantly more accurate than the control points in developing countries (44.4 meters RMSE; t-test p-value < 0.01). These findings indicate that Google Earth highresolution imagery has a horizontal positional accuracy that is sufficient for assessing moderate-resolution remote sensing products across most of the world's peri-urban areas.

  20. Teaching High-Accuracy Global Positioning System to Undergraduates Using Online Processing Services

    ERIC Educational Resources Information Center

    Wang, Guoquan

    2013-01-01

    High-accuracy Global Positioning System (GPS) has become an important geoscientific tool used to measure ground motions associated with plate movements, glacial movements, volcanoes, active faults, landslides, subsidence, slow earthquake events, as well as large earthquakes. Complex calculations are required in order to achieve high-precision…

  1. Portable device to assess dynamic accuracy of global positioning systems (GPS) receivers used in agricultural aircraft

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A device was designed to test the dynamic accuracy of Global Positioning System (GPS) receivers used in aerial vehicles. The system works by directing a sun-reflected light beam from the ground to the aircraft using mirrors. A photodetector is placed pointing downward from the aircraft and circuitry...

  2. Diagnostic accuracy of EEG changes during carotid endarterectomy in predicting perioperative strokes.

    PubMed

    Thirumala, Parthasarathy D; Thiagarajan, Karthy; Gedela, Satyanarayana; Crammond, Donald J; Balzer, Jeffrey R

    2016-03-01

    The 30 day stroke rate following carotid endarterectomy (CEA) ranges between 2-6%. Such periprocedural strokes are associated with a three-fold increased risk of mortality. Our primary aim was to determine the diagnostic accuracy of electroencephalogram (EEG) in predicting perioperative strokes through meta-analysis of existing literature. An extensive search for relevant literature was undertaken using PubMed and Web of Science databases. Studies were included after screening using predetermined criteria. Data was extracted and analyzed. Summary sensitivity, specificity and diagnostic odds ratio were obtained. Subgroup analysis of studies using eight or more EEG channels was done. Perioperative stroke rate for the cohort of 8765 patients was 1.75%. Pooled sensitivity and specificity of EEG changes in predicting these strokes were 52% (95% confidence interval [CI], 43-61%) and 84% (95% CI, 81-86%) respectively. Summary estimates of the subgroup were similar. The diagnostic odds ratio was 5.85 (95% CI, 3.71-9.22). For the observed stroke rate, the positive likelihood ratio was 3.25 while the negative predictive value was 98.99%. According to these results, patients with perioperative strokes have six times greater odds of experiencing an intraoperative change in EEG during CEA. EEG monitoring was found to be highly specific in predicting perioperative strokes after CEA.

  3. The Impact of Ionospheric Disturbances on High Accuracy Positioning in Brazil

    NASA Astrophysics Data System (ADS)

    Yang, L.; Park, J.; Susnik, A.; Aquino, M. H.; Dodson, A.

    2013-12-01

    High positioning accuracy is a key requirement to a number of applications with a high economic impact, such as precision agriculture, surveying, geodesy, land management, off-shore operations. Global Navigation Satellite Systems (GNSS) carrier phase measurement based techniques, such as Real Time Kinematic (RTK), Network-RTK (NRTK) and Precise Point Positioning (PPP), have played an important role in providing centimetre-level positioning accuracy, and become the core of the above applications. However these techniques are especially sensitive to ionospheric perturbations, in particular scintillation. Brazil sits in one of the most affected regions of the Earth and can be regarded as a test-bed for scenarios of the severe ionospheric condition. Over the Brazilian territory, the ionosphere behaves in a considerably unpredictable way and scintillation activity is very prominent, occurring especially after sunset hours. NRTK services may not be able to provide satisfactory accuracy, or even continuous positioning during strong scintillation periods. CALIBRA (Countering GNSS high Accuracy applications Limitations due to Ionospheric disturbances in BRAzil) started in late 2012 and is a project funded by the GSA (European GNSS Agency) and the European Commission under the Framework Program 7 to deliver improvements on carrier phase based high accuracy algorithms and their implementation in GNSS receivers, aiming to counter the adverse ionospheric effects over Brazil. As the first stage of this project, the ionospheric disturbances, which affect the applications of RTK, NRTK or PPP, are characterized. Typical problems include degraded positioning accuracy, difficulties in ambiguity fixing, NRTK network interpolation errors, long PPP convergence time etc. It will identify how GNSS observables and existing algorithms are degraded by ionosphere related phenomena, evaluating the impact on positioning techniques in terms of accuracy, integrity and availability. Through the

  4. Predictive Attitude Estimation Using Global Positioning System Signals

    NASA Technical Reports Server (NTRS)

    Crassidis, John L.; Markley, F. Landis; Lightsey, E. Glenn; Ketchum, Eleanor

    1997-01-01

    In this paper, a new algorithm is developed for attitude estimation using Global Positioning System (GPS) signals. The new algorithm is based on a predictive filtering scheme designed for spacecraft without rate measuring devices. The major advantage of this new algorithm over traditional Kalman filter approaches is that the model error is not assumed to represented by an unbiased Gaussian noise process with known covariance, but instead is determined during the estimation process. This is achieved by simultaneously solving system optimality conditions and an output error constraint. This approach is well suited for GPS attitude estimation since some error sources that contribute to attitude inaccuracy, such as signal multipath, are known to be non-Gaussian processes. Also, the predictive filter scheme can use either GPS signals or vector observations or a combination of both for attitude estimation, so that performance characteristics can be maintained during periods of GPS attitude sensor outage. The performance of the new algorithm is tested using flight data from the REX-2 spacecraft. Results are shown using the predictive filter to estimate the attitude from both GPS signals and magnetometer measurements, and comparing that solution to a magnetometer-only based solution. Results using the new estimation algorithm indicate that GPS-based solutions are verified to within 2 degrees using the magnetometer cross-check for the REX-2 spacecraft. GPS attitude accuracy of better than 1 degree is expected per axis, but cannot be reliably proven due to inaccuracies in the magnetic field model.

  5. Methods for evaluating the predictive accuracy of structural dynamic models

    NASA Technical Reports Server (NTRS)

    Hasselman, T. K.; Chrostowski, Jon D.

    1990-01-01

    Uncertainty of frequency response using the fuzzy set method and on-orbit response prediction using laboratory test data to refine an analytical model are emphasized with respect to large space structures. Two aspects of the fuzzy set approach were investigated relative to its application to large structural dynamics problems: (1) minimizing the number of parameters involved in computing possible intervals; and (2) the treatment of extrema which may occur in the parameter space enclosed by all possible combinations of the important parameters of the model. Extensive printer graphics were added to the SSID code to help facilitate model verification, and an application of this code to the LaRC Ten Bay Truss is included in the appendix to illustrate this graphics capability.

  6. Accuracy of gestalt perception of acute chest pain in predicting coronary artery disease

    PubMed Central

    das Virgens, Cláudio Marcelo Bittencourt; Lemos Jr, Laudenor; Noya-Rabelo, Márcia; Carvalhal, Manuela Campelo; Cerqueira Junior, Antônio Maurício dos Santos; Lopes, Fernanda Oliveira de Andrade; de Sá, Nicole Cruz; Suerdieck, Jéssica Gonzalez; de Souza, Thiago Menezes Barbosa; Correia, Vitor Calixto de Almeida; Sodré, Gabriella Sant'Ana; da Silva, André Barcelos; Alexandre, Felipe Kalil Beirão; Ferreira, Felipe Rodrigues Marques; Correia, Luís Cláudio Lemos

    2017-01-01

    AIM To test accuracy and reproducibility of gestalt to predict obstructive coronary artery disease (CAD) in patients with acute chest pain. METHODS We studied individuals who were consecutively admitted to our Chest Pain Unit. At admission, investigators performed a standardized interview and recorded 14 chest pain features. Based on these features, a cardiologist who was blind to other clinical characteristics made unstructured judgment of CAD probability, both numerically and categorically. As the reference standard for testing the accuracy of gestalt, angiography was required to rule-in CAD, while either angiography or non-invasive test could be used to rule-out. In order to assess reproducibility, a second cardiologist did the same procedure. RESULTS In a sample of 330 patients, the prevalence of obstructive CAD was 48%. Gestalt’s numerical probability was associated with CAD, but the area under the curve of 0.61 (95%CI: 0.55-0.67) indicated low level of accuracy. Accordingly, categorical definition of typical chest pain had a sensitivity of 48% (95%CI: 40%-55%) and specificity of 66% (95%CI: 59%-73%), yielding a negligible positive likelihood ratio of 1.4 (95%CI: 0.65-2.0) and negative likelihood ratio of 0.79 (95%CI: 0.62-1.02). Agreement between the two cardiologists was poor in the numerical classification (95% limits of agreement = -71% to 51%) and categorical definition of typical pain (Kappa = 0.29; 95%CI: 0.21-0.37). CONCLUSION Clinical judgment based on a combination of chest pain features is neither accurate nor reproducible in predicting obstructive CAD in the acute setting.

  7. Positioning Accuracy in Stereotactic Radiotherapy Using a Mask System With Added Vacuum Mouth Piece and Stereoscopic X-Ray Positioning

    SciTech Connect

    Santvoort, Jan van Wiggenraad, Ruud; Bos, Petra

    2008-09-01

    Purpose: For cranial patients receiving stereotactic radiotherapy, we use the Exactrac stereoscopic X-ray system to optimize patient positioning. Patients are immobilized with the BrainLAB Mask System (BrainLAB, Feldkirchen, Germany). We have developed an adapter to this system that accommodates a vacuum mouth piece (VMP). Measurements with the Exactrac system have been performed to study the positioning accuracy after corrections with this system and to evaluate the accuracy of the VMP vs. the standard available upper jaw support (UJS). Methods and Materials: Positioning results were collected for 20 patients with the UJS and 20 patients with the VMP, before treatment (1,122 fractions) and after treatment (400 fractions). For all 6 degrees of freedom the average, the random error and systematic error were calculated. Results: The average vector length before and after correction with the Exactrac system was 2.1 {+-} 1.2 mm and 0.7 {+-} 0.6 mm respectively for UJS and 1.7 {+-} 0.7 mm and 0.4 {+-} 0.4 mm for VMP. Interfraction positioning for translations was greatly improved after correction with the Exactrac system (p < 0.0005) and is better with VMP than with UJS (p = 0.005). Outliers were greatly reduced. Interfraction rotations were significantly smaller for VMP. Intrafraction errors for vertical and longitudinal translations and for rotations were smaller for the VMP. Conclusions: Positioning correction using the Exactrac X-ray system greatly improves accuracy. Adding the VMP results in even better patient fixation and smaller rotations, making it a useful addition to the Mask System. Combined, this is a convenient and accurate alternative to invasive fixation methods.

  8. High accuracy position response calibration method for a micro-channel plate ion detector

    NASA Astrophysics Data System (ADS)

    Hong, R.; Leredde, A.; Bagdasarova, Y.; Fléchard, X.; García, A.; Müller, P.; Knecht, A.; Liénard, E.; Kossin, M.; Sternberg, M. G.; Swanson, H. E.; Zumwalt, D. W.

    2016-11-01

    We have developed a position response calibration method for a micro-channel plate (MCP) detector with a delay-line anode position readout scheme. Using an in situ calibration mask, an accuracy of 8 μm and a resolution of 85 μm (FWHM) have been achieved for MeV-scale α particles and ions with energies of ∼10 keV. At this level of accuracy, the difference between the MCP position responses to high-energy α particles and low-energy ions is significant. The improved performance of the MCP detector can find applications in many fields of AMO and nuclear physics. In our case, it helps reducing systematic uncertainties in a high-precision nuclear β-decay experiment.

  9. Posterior Predictive Checks for Conditional Independence between Response Time and Accuracy

    ERIC Educational Resources Information Center

    Bolsinova, Maria; Tijmstra, Jesper

    2016-01-01

    Conditional independence (CI) between response time and response accuracy is a fundamental assumption of many joint models for time and accuracy used in educational measurement. In this study, posterior predictive checks (PPCs) are proposed for testing this assumption. These PPCs are based on three discrepancy measures reflecting different…

  10. Long-term deflections of reinforced concrete elements: accuracy analysis of predictions by different methods

    NASA Astrophysics Data System (ADS)

    Gribniak, Viktor; Bacinskas, Darius; Kacianauskas, Rimantas; Kaklauskas, Gintaris; Torres, Lluis

    2013-08-01

    Long-term deflection response of reinforced concrete flexural members is influenced by the interaction of complex physical phenomena, such as concrete creep, shrinkage and cracking, which makes their prediction difficult. A number of approaches are proposed by design codes with different degrees of simplification and accuracy. This paper statistically investigates accuracy of long-term deflection predictions made by some of the most widely used design codes ( Eurocode 2, ACI 318, ACI 435, and the new Russian code SP 52-101) and a numerical technique proposed by the authors. The accuracy is analyzed using test data of 322 reinforced concrete members from 27 test programs reported in the literature. The predictions of each technique are discussed, and a comparative analysis is made showing the influence of different parameters, such as sustained loading duration, compressive strength of concrete, loading intensity and reinforcement ratio, on the prediction accuracy.

  11. Adjusted Clinical Groups: Predictive Accuracy for Medicaid Enrollees in Three States

    PubMed Central

    Adams, E. Kathleen; Bronstein, Janet M.; Raskind-Hood, Cheryl

    2002-01-01

    Actuarial split-sample methods were used to assess predictive accuracy of adjusted clinical groups (ACGs) for Medicaid enrollees in Georgia, Mississippi (lagging in managed care penetration), and California. Accuracy for two non-random groups—high-cost and located in urban poor areas—was assessed. Measures for random groups were derived with and without short-term enrollees to assess the effect of turnover on predictive accuracy. ACGs improved predictive accuracy for high-cost conditions in all States, but did so only for those in Georgia's poorest urban areas. Higher and more unpredictable expenses of short-term enrollees moderated the predictive power of ACGs. This limitation was significant in Mississippi due in part, to that State's very high proportion of short-term enrollees. PMID:12545598

  12. Interspecies translation of disease networks increases robustness and predictive accuracy.

    PubMed

    Anvar, Seyed Yahya; Tucker, Allan; Vinciotti, Veronica; Venema, Andrea; van Ommen, Gert-Jan B; van der Maarel, Silvere M; Raz, Vered; 't Hoen, Peter A C

    2011-11-01

    Gene regulatory networks give important insights into the mechanisms underlying physiology and pathophysiology. The derivation of gene regulatory networks from high-throughput expression data via machine learning strategies is problematic as the reliability of these models is often compromised by limited and highly variable samples, heterogeneity in transcript isoforms, noise, and other artifacts. Here, we develop a novel algorithm, dubbed Dandelion, in which we construct and train intraspecies Bayesian networks that are translated and assessed on independent test sets from other species in a reiterative procedure. The interspecies disease networks are subjected to multi-layers of analysis and evaluation, leading to the identification of the most consistent relationships within the network structure. In this study, we demonstrate the performance of our algorithms on datasets from animal models of oculopharyngeal muscular dystrophy (OPMD) and patient materials. We show that the interspecies network of genes coding for the proteasome provide highly accurate predictions on gene expression levels and disease phenotype. Moreover, the cross-species translation increases the stability and robustness of these networks. Unlike existing modeling approaches, our algorithms do not require assumptions on notoriously difficult one-to-one mapping of protein orthologues or alternative transcripts and can deal with missing data. We show that the identified key components of the OPMD disease network can be confirmed in an unseen and independent disease model. This study presents a state-of-the-art strategy in constructing interspecies disease networks that provide crucial information on regulatory relationships among genes, leading to better understanding of the disease molecular mechanisms.

  13. Screening Characteristics of TIMI Score in Predicting Acute Coronary Syndrome Outcome; a Diagnostic Accuracy Study

    PubMed Central

    Alavi-Moghaddam, Mostafa; Safari, Saeed; Alavi-Moghaddam, Hamideh

    2017-01-01

    Introduction: In cases with potential diagnosis of ischemic chest pain, screening high risk patients for adverse outcomes would be very helpful. The present study was designed aiming to determine the diagnostic accuracy of thrombolysis in myocardial infarction (TIMI) score in Patients with potential diagnosis of ischemic chest pain. Method: This diagnostic accuracy study was designed to evaluate the screening performance characteristics of TIMI score in predicting 30-day outcomes of mortality, myocardial infarction (MI), and need for revascularization in patients presenting to ED with complaint of typical chest pain and diagnosis of unstable angina or Non-ST elevation MI. Results: 901 patients with the mean age of 58.17 ± 15.00 years (19-90) were studied (52.9% male). Mean TIMI score of the studied patients was 0.97 ± 0.93 (0-5) and the highest frequency of the score belonged to 0 to 2 with 37.2%, 35.3%, and 21.4%, respectively. In total, 170 (18.8%) patients experienced the outcomes evaluated in this study. Total sensitivity, specificity, positive and negative predictive value, and positive and negative likelihood ratio of TIMI score were 20 (95% CI: 17 – 24), 99 (95% CI: 97 – 100), 98 (95% CI: 93 – 100), 42 (95% CI: 39 – 46), 58 (95% CI: 14 – 229), and 1.3 (95% CI: 1.2 – 1.4), respectively. Area under the ROC curve of this system for prediction of 30-day mortality, MI, and need for revascularization were 0.51 (95% CI: 0.47 – 0.55), 0.58 (95% CI: 0.54 – 0.62) and 0.56 (95% CI: 0.52 – 0.60), respectively. Conclusion: Based on the findings of the present study, it seems that TIMI score has a high specificity in predicting 30-day adverse outcomes of mortality, MI, and need for revascularization following acute coronary syndrome. However, since its sensitivity, negative predictive value, and negative likelihood ratio are low, it cannot be used as a proper screening tool for ruling out low risk patients in ED. PMID:28286825

  14. Accuracy analysis of a mobile tracking system for angular position determination of flying targets

    NASA Astrophysics Data System (ADS)

    Walther, Andreas; Buske, Ivo; Riede, Wolfgang

    2016-10-01

    Lasers arouse an increasing interest in remote sensing applications. In order to deliver as much as possible of the available laser power onto a flying object the subsystems of a beam control system have to operate precisely together. One important subsystem is responsible for determination of the target's angular position. Here, we focus on an optical system for measuring precisely the angular position of flying objects. We designed this subunit of a beam control system exclusively from readily available commercial-off-the-shelf components. Two industrial cameras were used for angle measuring and for guiding the system to the position of the flying object. Both cameras are mounted on a modified astronomical mount with high-precision angle encoders. To achieve a high accuracy we temporally synchronize the acquisition of the angle from the pan tilt unit with the exposure of the camera. Therefore, a FPGA-based readout device for the rotary encoders was designed and implemented. Additionally, we determined and evaluated the influence of the distortion of the lenses to the measurement. We investigated various scenarios to determine the accuracy and the limitations of our system for angular position determination of flying targets. Performance tests were taken indoor and outdoor at our test sites. A target can be mounted on a fast moving linear stage. The position of this linear stage is continuously read out by a high resolution encoder so we know the target's position with a dynamic accuracy in the range of a few μm. With this setup we evaluated the spatial resolution of our tracking system. We showed that the presented system can determine the angular position of fast flying objects with an uncertainty of only 2 μrad RMS. With this mobile tracking system for angular position determination of flying targets we designed an accurate cost-efficient opportunity for further developments.

  15. Rapid Centroids and the Refined Position Accuracy of the Swift Gamma-ray Burst Catalogue

    NASA Technical Reports Server (NTRS)

    Hill, J. E.; Angelini, L.; Moretti, A.; Morris, D. C.; Racusin, J.; Burrows, D. N.; Beardmore, A. P.; Campana, S.; Capalbi, M.; Kennea, J. A.

    2005-01-01

    The Swift X-ray Telescope autonomously refines the Burst Alert Telescope positions (approx.1-4' uncertainty) to better than 5 arcsec, within 5 seconds of target acquisition by the observatory for typical bursts. The results of the rapid positioning capability of the XRT are presented here for both known sources and newly discovered GRBs, demonstrating the ability to automatically utilize one of two integration times according to the burst brightness, and to correct the position for alignment offsets caused by the fast pointing performance and variable thermal environment of the satellite as measured by the Telescope Alignment Monitor. We present an evaluation of the position accuracy for both the onboard centroiding software and the ground software for the calibration targets and show that a significant improvement in position accuracy is obtained if the boresight detector position is optimized relative to the spacecraft pointing. Finally, we present an updated catalogue of Swift GRB X-ray positions obtained in Photon Counting Mode using the improved, calibrated boresight.

  16. Accuracy of predicting genomic breeding values for residual feed intake in Angus and Charolais beef cattle.

    PubMed

    Chen, L; Schenkel, F; Vinsky, M; Crews, D H; Li, C

    2013-10-01

    In beef cattle, phenotypic data that are difficult and/or costly to measure, such as feed efficiency, and DNA marker genotypes are usually available on a small number of animals of different breeds or populations. To achieve a maximal accuracy of genomic prediction using the phenotype and genotype data, strategies for forming a training population to predict genomic breeding values (GEBV) of the selection candidates need to be evaluated. In this study, we examined the accuracy of predicting GEBV for residual feed intake (RFI) based on 522 Angus and 395 Charolais steers genotyped on SNP with the Illumina Bovine SNP50 Beadchip for 3 training population forming strategies: within breed, across breed, and by pooling data from the 2 breeds (i.e., combined). Two other scenarios with the training and validation data split by birth year and by sire family within a breed were also investigated to assess the impact of genetic relationships on the accuracy of genomic prediction. Three statistical methods including the best linear unbiased prediction with the relationship matrix defined based on the pedigree (PBLUP), based on the SNP genotypes (GBLUP), and a Bayesian method (BayesB) were used to predict the GEBV. The results showed that the accuracy of the GEBV prediction was the highest when the prediction was within breed and when the validation population had greater genetic relationships with the training population, with a maximum of 0.58 for Angus and 0.64 for Charolais. The within-breed prediction accuracies dropped to 0.29 and 0.38, respectively, when the validation populations had a minimal pedigree link with the training population. When the training population of a different breed was used to predict the GEBV of the validation population, that is, across-breed genomic prediction, the accuracies were further reduced to 0.10 to 0.22, depending on the prediction method used. Pooling data from the 2 breeds to form the training population resulted in accuracies increased

  17. Enhanced Positioning Algorithm of ARPS for Improving Accuracy and Expanding Service Coverage

    PubMed Central

    Lee, Kyuman; Baek, Hoki; Lim, Jaesung

    2016-01-01

    The airborne relay-based positioning system (ARPS), which employs the relaying of navigation signals, was proposed as an alternative positioning system. However, the ARPS has limitations, such as relatively large vertical error and service restrictions, because firstly, the user position is estimated based on airborne relays that are located in one direction, and secondly, the positioning is processed using only relayed navigation signals. In this paper, we propose an enhanced positioning algorithm to improve the performance of the ARPS. The main idea of the enhanced algorithm is the adaptable use of either virtual or direct measurements of reference stations in the calculation process based on the structural features of the ARPS. Unlike the existing two-step algorithm for airborne relay and user positioning, the enhanced algorithm is divided into two cases based on whether the required number of navigation signals for user positioning is met. In the first case, where the number of signals is greater than four, the user first estimates the positions of the airborne relays and its own initial position. Then, the user position is re-estimated by integrating a virtual measurement of a reference station that is calculated using the initial estimated user position and known reference positions. To prevent performance degradation, the re-estimation is performed after determining its requirement through comparing the expected position errors. If the navigation signals are insufficient, such as when the user is outside of airborne relay coverage, the user position is estimated by additionally using direct signal measurements of the reference stations in place of absent relayed signals. The simulation results demonstrate that a higher accuracy level can be achieved because the user position is estimated based on the measurements of airborne relays and a ground station. Furthermore, the service coverage is expanded by using direct measurements of reference stations for user

  18. Accuracy of an acoustic location system for monitoring the position of duetting songbirds in tropical forest

    PubMed Central

    Mennill, Daniel J.; Burt, John M.; Fristrup, Kurt M.; Vehrencamp, Sandra L.

    2008-01-01

    A field test was conducted on the accuracy of an eight-microphone acoustic location system designed to triangulate the position of duetting rufous-and-white wrens (Thryothorus rufalbus) in Costa Rica’s humid evergreen forest. Eight microphones were set up in the breeding territories of twenty pairs of wrens, with an average inter-microphone distance of 75.2±2.6 m. The array of microphones was used to record antiphonal duets broadcast through stereo loudspeakers. The positions of the loudspeakers were then estimated by evaluating the delay with which the eight microphones recorded the broadcast sounds. Position estimates were compared to coordinates surveyed with a global-positioning system (GPS). The acoustic location system estimated the position of loudspeakers with an error of 2.82±0.26 m and calculated the distance between the “male” and “female” loudspeakers with an error of 2.12±0.42 m. Given the large range of distances between duetting birds, this relatively low level of error demonstrates that the acoustic location system is a useful tool for studying avian duets. Location error was influenced partly by the difficulties inherent in collecting high accuracy GPS coordinates of microphone positions underneath a lush tropical canopy, and partly by the complicating influence of irregular topography and thick vegetation on sound transmission. PMID:16708941

  19. Improving protein–protein interactions prediction accuracy using protein evolutionary information and relevance vector machine model

    PubMed Central

    An, Ji‐Yong; Meng, Fan‐Rong; Chen, Xing; Yan, Gui‐Ying; Hu, Ji‐Pu

    2016-01-01

    Abstract Predicting protein–protein interactions (PPIs) is a challenging task and essential to construct the protein interaction networks, which is important for facilitating our understanding of the mechanisms of biological systems. Although a number of high‐throughput technologies have been proposed to predict PPIs, there are unavoidable shortcomings, including high cost, time intensity, and inherently high false positive rates. For these reasons, many computational methods have been proposed for predicting PPIs. However, the problem is still far from being solved. In this article, we propose a novel computational method called RVM‐BiGP that combines the relevance vector machine (RVM) model and Bi‐gram Probabilities (BiGP) for PPIs detection from protein sequences. The major improvement includes (1) Protein sequences are represented using the Bi‐gram probabilities (BiGP) feature representation on a Position Specific Scoring Matrix (PSSM), in which the protein evolutionary information is contained; (2) For reducing the influence of noise, the Principal Component Analysis (PCA) method is used to reduce the dimension of BiGP vector; (3) The powerful and robust Relevance Vector Machine (RVM) algorithm is used for classification. Five‐fold cross‐validation experiments executed on yeast and Helicobacter pylori datasets, which achieved very high accuracies of 94.57 and 90.57%, respectively. Experimental results are significantly better than previous methods. To further evaluate the proposed method, we compare it with the state‐of‐the‐art support vector machine (SVM) classifier on the yeast dataset. The experimental results demonstrate that our RVM‐BiGP method is significantly better than the SVM‐based method. In addition, we achieved 97.15% accuracy on imbalance yeast dataset, which is higher than that of balance yeast dataset. The promising experimental results show the efficiency and robust of the proposed method, which can be an automatic

  20. Accuracies of Positioning and Geodata Using Helicopters for Geodetic and Geophysical Surveys

    NASA Astrophysics Data System (ADS)

    Bielenberg, O.; Meyer, U.; Vasterling, M.

    2010-12-01

    : Helicopters are frequently used for airborne surveys in geodesy and geophysics. The range of accuracies needed for proper data reconstruction is wide spread from some meters for airborne magnetics to centimeters for laser scanner measurements. This study lists up to date methods of online and offline positioning, discusses their accuracies that may be achieved and relates them to different geodetic as geophysical surveys in different types of terrain. The goal is to match helicopter positioning methods with the given survey task to optimize results and work efficiency. Some fundamental studies have been conducted on helicopter work during the DESIRE (Dead Sea Integrated Research) project in Israel and Jordan which have been continued in Germany. These studies include the impact of vibrations on INS, IMU and gravity meter systems as well as the choice of antenna locations on the shell of the helicopter.

  1. Evaluation of the Predictive Accuracy of Five Whole Building Baseline Models

    SciTech Connect

    Granderson, Jessica; Price, Phillip

    2012-08-31

    This report documents the relative and absolute performance of five baseline models used to characterize whole­building energy consumption. The Pulse Adaptive Model1, multi-­parameter change-­point, mean-week, day-­time-emperature, and LBNL models were evaluated according to a number of statistical ‘goodness of fit’ metrics, to determine their accuracy in characterizing the energy consumption of a set of 29 buildings. The baseline training period, prediction horizon, and predicted energy quantity (daily, weekly, and monthly energy consumption) were varied, and model predictions were compared to interval meter data to determine the accuracy of each model. Three combinations of baseline training periods and prediction horizons were considered: 6 months of training to generate a 12-­month prediction; 9 months of training to generate a 7-month prediction; and 12 months of training to generate a 6- month prediction.

  2. Dispersal and extrapolation on the accuracy of temporal predictions from distribution models for the Darwin's frog.

    PubMed

    Uribe-Rivera, David E; Soto-Azat, Claudio; Valenzuela-Sánchez, Andrés; Bizama, Gustavo; Simonetti, Javier A; Pliscoff, Patricio

    2017-04-11

    Climate change is a major threat to biodiversity; the development of models that reliably predict its effects on species distributions is a priority for conservation biogeography. Two of the main issues for accurate temporal predictions from Species Distribution Models (SDM) are model extrapolation and unrealistic dispersal scenarios. We assessed the consequences of these issues on the accuracy of climate-driven SDM predictions for the dispersal-limited Darwin's frog Rhinoderma darwinii in South America. We calibrated models using historical data (1950-1975) and projected them across 40 years to predict distribution under current climatic conditions, assessing predictive accuracy through the area under the ROC curve (AUC) and True Skill Statistics (TSS), contrasting binary model predictions against temporal-independent validation dataset (i.e. current presences/absences). To assess the effects of incorporating dispersal processes we compared the predictive accuracy of dispersal constrained models with no dispersal limited SDMs; and to assess the effects of model extrapolation on the predictive accuracy of SDMs, we compared this between extrapolated and no extrapolated areas. The incorporation of dispersal processes enhanced predictive accuracy, mainly due to a decrease in the false presence rate of model predictions, which is consistent with discrimination of suitable but inaccessible habitat. This also had consequences on range size changes over time, which is the most used proxy for extinction risk from climate change. The area of current climatic conditions that was absent in the baseline conditions (i.e. extrapolated areas) represents 39% of the study area, leading to a significant decrease in predictive accuracy of model predictions for those areas. Our results highlight 1) Incorporating dispersal processes can improve predictive accuracy of temporal transference of SDMs, and reduce uncertainties of extinction risk assessments from global change; 2) As

  3. A machine learning approach to the accurate prediction of multi-leaf collimator positional errors

    NASA Astrophysics Data System (ADS)

    Carlson, Joel N. K.; Park, Jong Min; Park, So-Yeon; In Park, Jong; Choi, Yunseok; Ye, Sung-Joon

    2016-03-01

    Discrepancies between planned and delivered movements of multi-leaf collimators (MLCs) are an important source of errors in dose distributions during radiotherapy. In this work we used machine learning techniques to train models to predict these discrepancies, assessed the accuracy of the model predictions, and examined the impact these errors have on quality assurance (QA) procedures and dosimetry. Predictive leaf motion parameters for the models were calculated from the plan files, such as leaf position and velocity, whether the leaf was moving towards or away from the isocenter of the MLC, and many others. Differences in positions between synchronized DICOM-RT planning files and DynaLog files reported during QA delivery were used as a target response for training of the models. The final model is capable of predicting MLC positions during delivery to a high degree of accuracy. For moving MLC leaves, predicted positions were shown to be significantly closer to delivered positions than were planned positions. By incorporating predicted positions into dose calculations in the TPS, increases were shown in gamma passing rates against measured dose distributions recorded during QA delivery. For instance, head and neck plans with 1%/2 mm gamma criteria had an average increase in passing rate of 4.17% (SD  =  1.54%). This indicates that the inclusion of predictions during dose calculation leads to a more realistic representation of plan delivery. To assess impact on the patient, dose volumetric histograms (DVH) using delivered positions were calculated for comparison with planned and predicted DVHs. In all cases, predicted dose volumetric parameters were in closer agreement to the delivered parameters than were the planned parameters, particularly for organs at risk on the periphery of the treatment area. By incorporating the predicted positions into the TPS, the treatment planner is given a more realistic view of the dose distribution as it will truly be

  4. Accuracy of WAAS-enabled GPS for the determination of position and speed over ground.

    PubMed

    Witte, T H; Wilson, A M

    2005-08-01

    The Global Positioning System (GPS) offers many advantages over conventional methods for the determination of subject speed during biomechanical studies. Recent advances in GPS technology, in particular the implementation of the Wide-Angle Augmentation System and European Geostationary Navigation Overlay Service (WAAS/EGNOS), mean that small, highly portable units are available offering the potential of superior accuracy in the determination of both position and speed. This study set out to examine the accuracy of a WAAS-enabled GPS unit for the determination of position and speed. Comparison with the new and published data showed significant enhancements in both position and speed accuracy over a non-WAAS system. Position data collected during straight line cycling showed significantly lower sample-to-sample variation (mean absolute deviation from straight line 0.11 vs. 0.78 m) and greater repeatability from trial to trial (mean absolute deviation from actual path 0.37 vs. 4.8 m) for the WAAS-enabled unit compared to the non-WAAS unit. The speed determined by the WAAS-enabled GPS receiver during cycling in a straight line was within 0.2 ms(-1) of the actual speed measured for 57% of the values with 82% lying within 0.4 ms(-1), however, the data tended towards underestimation of speed during circle cycling, with 65% of values within 0.2 ms(-1) and 87% within 0.4 ms(-1) of the actual value. Local dGPS and dual frequency techniques are more accurate still, however, traditional differential GPS (dGPS), employing FM radio transmission of correction data to a separate receiver, now offers no advantage over WAAS and appears redundant.

  5. Accuracy in GPS/Acoustic positioning on a moored buoy moving around far from the optimal position

    NASA Astrophysics Data System (ADS)

    Imano, M.; Kido, M.; Ohta, Y.; Takahashi, N.; Fukuda, T.; Ochi, H.; Hino, R.

    2015-12-01

    For detecting the seafloor crustal deformation and Tsunami associated with large earthquakes in real-time, it is necessary to monitor them just above the possible source region. For this purpose, we have been dedicated in developing a real-time continuous observation system using a multi-purpose moored buoy. Sea-trials of the system have been carried out near the Nanakai trough in 2013 and 2014 (Takahashi et al., 2014). We especially focused on the GPS/Acoustic measurement (GPS/A) in the system for horizontal crustal movement. The GPS/A on a moored buoy has a critical drawback compared to the traditional ones, in which the data can be stacked over ranging points fixed at an optimal position. Accuracy in positioning with a single ranging from an arbitrary point is the subject to be improved in this study. Here, we report the positioning results in the buoy system using data in the 2014 sea-trial and demonstrate the improvement of the result. We also address the potential resolving power in the positioning using synthetic tests. The target GPS/A site consists of six seafloor transponders (PXPs) forming a small inner- and a large outer-triangles. The bottom of the moored cable is anchored nearly the center of the triangles. In the sea-trial, 11 times successive ranging was scheduled once a week, and we plotted positioning results from different buoy position. We confirmed that scatter in positioning using six PXPs simultaneously is ten times smaller than that using individual triangle separately. Next, we modified the definition of the PXP array geometry using data obtained in a campaign observation. Definition of an array geometry is insensitive as far as ranging is made in the same position, however, severely affects the positioning when ranging is made from various positions like the moored buoy. The modified PXP array is slightly smaller and 2m deeper than the original one. We found that the scatter of positioning results in the sea-trial is reduced from 4m to 1

  6. Enhancing the prediction accuracy of bovine lameness models through transformations of limb movement variables.

    PubMed

    Liu, J; Neerchal, N K; Tasch, U; Dyer, R M; Rajkondawar, P G

    2009-06-01

    The issue of modeling bovine lameness was explored by testing the hypothesis that B-spline transformation of limb movement variables (LMV) employed in predictive models improved model accuracy. The objectives were to determine the effect of number of B-spline knots and the degree of the underlying polynomial approximation (degree of freedom) on model accuracy. Knot number used in B-spline transformation improved model accuracy by improving model specificity and to a lesser extent model sensitivity. Degree of polynomial approximation had no effect on model predictive accuracy from the data set of 261 cows. Model stability, defined as changes in predictive accuracy associated with the superimposition of perturbations (0.5 and 1.0%) in LMV on the measured data, was explored. Model specificity and to a lesser degree, sensitivity, increased with increased knot number across data set perturbations. Specificity and sensitivity increased by 43 and 11%, respectively, when knot number increased from 0 to 7 for a perturbation level of 0.5%. When the perturbation level was 1%, the corresponding increases in specificity and sensitivity were 32 and 4%, respectively. Nevertheless, different levels of LMV perturbation varied the optimal knot number associated with highest model accuracy. The optimal knot number for 0.5% perturbation was 8, whereas for 1% perturbation the optimal knot number was 7. The B-spline transformation improved specificity and sensitivity of predictive models for lameness, provided the appropriate number of knots was selected.

  7. Assessment of the genomic prediction accuracy for feed efficiency traits in meat-type chickens

    PubMed Central

    Wang, Jie; Ma, Jie; Shu, Dingming; Lund, Mogens Sandø; Su, Guosheng; Qu, Hao

    2017-01-01

    Feed represents the major cost of chicken production. Selection for improving feed utilization is a feasible way to reduce feed cost and greenhouse gas emissions. The objectives of this study were to investigate the efficiency of genomic prediction for feed conversion ratio (FCR), residual feed intake (RFI), average daily gain (ADG) and average daily feed intake (ADFI) and to assess the impact of selection for feed efficiency traits FCR and RFI on eviscerating percentage (EP), breast muscle percentage (BMP) and leg muscle percentage (LMP) in meat-type chickens. Genomic prediction was assessed using a 4-fold cross-validation for two validation scenarios. The first scenario was a random family sampling validation (CVF), and the second scenario was a random individual sampling validation (CVR). Variance components were estimated based on the genomic relationship built with single nucleotide polymorphism markers. Genomic estimated breeding values (GEBV) were predicted using a genomic best linear unbiased prediction model. The accuracies of GEBV were evaluated in two ways: the correlation between GEBV and corrected phenotypic value divided by the square root of heritability, i.e., the correlation-based accuracy, and model-based theoretical accuracy. Breeding values were also predicted using a conventional pedigree-based best linear unbiased prediction model in order to compare accuracies of genomic and conventional predictions. The heritability estimates of FCR and RFI were 0.29 and 0.50, respectively. The heritability estimates of ADG, ADFI, EP, BMP and LMP ranged from 0.34 to 0.53. In the CVF scenario, the correlation-based accuracy and the theoretical accuracy of genomic prediction for FCR were slightly higher than those for RFI. The correlation-based accuracies for FCR, RFI, ADG and ADFI were 0.360, 0.284, 0.574 and 0.520, respectively, and the model-based theoretical accuracies were 0.420, 0.414, 0.401 and 0.382, respectively. In the CVR scenario, the correlation

  8. Position Accuracy Improvement by Implementing the DGNSS-CP Algorithm in Smartphones

    PubMed Central

    Yoon, Donghwan; Kee, Changdon; Seo, Jiwon; Park, Byungwoon

    2016-01-01

    The position accuracy of Global Navigation Satellite System (GNSS) modules is one of the most significant factors in determining the feasibility of new location-based services for smartphones. Considering the structure of current smartphones, it is impossible to apply the ordinary range-domain Differential GNSS (DGNSS) method. Therefore, this paper describes and applies a DGNSS-correction projection method to a commercial smartphone. First, the local line-of-sight unit vector is calculated using the elevation and azimuth angle provided in the position-related output of Android’s LocationManager, and this is transformed to Earth-centered, Earth-fixed coordinates for use. To achieve position-domain correction for satellite systems other than GPS, such as GLONASS and BeiDou, the relevant line-of-sight unit vectors are used to construct an observation matrix suitable for multiple constellations. The results of static and dynamic tests show that the standalone GNSS accuracy is improved by about 30%–60%, thereby reducing the existing error of 3–4 m to just 1 m. The proposed algorithm enables the position error to be directly corrected via software, without the need to alter the hardware and infrastructure of the smartphone. This method of implementation and the subsequent improvement in performance are expected to be highly effective to portability and cost saving. PMID:27322284

  9. Position Accuracy Improvement by Implementing the DGNSS-CP Algorithm in Smartphones.

    PubMed

    Yoon, Donghwan; Kee, Changdon; Seo, Jiwon; Park, Byungwoon

    2016-06-18

    The position accuracy of Global Navigation Satellite System (GNSS) modules is one of the most significant factors in determining the feasibility of new location-based services for smartphones. Considering the structure of current smartphones, it is impossible to apply the ordinary range-domain Differential GNSS (DGNSS) method. Therefore, this paper describes and applies a DGNSS-correction projection method to a commercial smartphone. First, the local line-of-sight unit vector is calculated using the elevation and azimuth angle provided in the position-related output of Android's LocationManager, and this is transformed to Earth-centered, Earth-fixed coordinates for use. To achieve position-domain correction for satellite systems other than GPS, such as GLONASS and BeiDou, the relevant line-of-sight unit vectors are used to construct an observation matrix suitable for multiple constellations. The results of static and dynamic tests show that the standalone GNSS accuracy is improved by about 30%-60%, thereby reducing the existing error of 3-4 m to just 1 m. The proposed algorithm enables the position error to be directly corrected via software, without the need to alter the hardware and infrastructure of the smartphone. This method of implementation and the subsequent improvement in performance are expected to be highly effective to portability and cost saving.

  10. A new source difference artificial neural network for enhanced positioning accuracy

    NASA Astrophysics Data System (ADS)

    Bhatt, Deepak; Aggarwal, Priyanka; Devabhaktuni, Vijay; Bhattacharya, Prabir

    2012-10-01

    Integrated inertial navigation system (INS) and global positioning system (GPS) units provide reliable navigation solution compared to standalone INS or GPS. Traditional Kalman filter-based INS/GPS integration schemes have several inadequacies related to sensor error model and immunity to noise. Alternatively, multi-layer perceptron (MLP) neural networks with three layers have been implemented to improve the position accuracy of the integrated system. However, MLP neural networks show poor accuracy for low-cost INS because of the large inherent sensor errors. For the first time the paper demonstrates the use of knowledge-based source difference artificial neural network (SDANN) to improve navigation performance of low-cost sensor, with or without external aiding sources. Unlike the conventional MLP or artificial neural networks (ANN), the structure of SDANN consists of two MLP neural networks called the coarse model and the difference model. The coarse model learns the input-output data relationship whereas the difference model adds knowledge to the system and fine-tunes the coarse model output by learning the associated training or estimation error. Our proposed SDANN model illustrated a significant improvement in navigation accuracy of up to 81% over conventional MLP. The results demonstrate that the proposed SDANN method is effective for GPS/INS integration schemes using low-cost inertial sensors, with and without GPS.

  11. Influence of Pedometer Position on Pedometer Accuracy at Various Walking Speeds: A Comparative Study

    PubMed Central

    Lovis, Christian

    2016-01-01

    Background Demographic growth in conjunction with the rise of chronic diseases is increasing the pressure on health care systems in most OECD countries. Physical activity is known to be an essential factor in improving or maintaining good health. Walking is especially recommended, as it is an activity that can easily be performed by most people without constraints. Pedometers have been extensively used as an incentive to motivate people to become more active. However, a recognized problem with these devices is their diminishing accuracy associated with decreased walking speed. The arrival on the consumer market of new devices, worn indifferently either at the waist, wrist, or as a necklace, gives rise to new questions regarding their accuracy at these different positions. Objective Our objective was to assess the performance of 4 pedometers (iHealth activity monitor, Withings Pulse O2, Misfit Shine, and Garmin vívofit) and compare their accuracy according to their position worn, and at various walking speeds. Methods We conducted this study in a controlled environment with 21 healthy adults required to walk 100 m at 3 different paces (0.4 m/s, 0.6 m/s, and 0.8 m/s) regulated by means of a string attached between their legs at the level of their ankles and a metronome ticking the cadence. To obtain baseline values, we asked the participants to walk 200 m at their own pace. Results A decrease of accuracy was positively correlated with reduced speed for all pedometers (12% mean error at self-selected pace, 27% mean error at 0.8 m/s, 52% mean error at 0.6 m/s, and 76% mean error at 0.4 m/s). Although the position of the pedometer on the person did not significantly influence its accuracy, some interesting tendencies can be highlighted in 2 settings: (1) positioning the pedometer at the waist at a speed greater than 0.8 m/s or as a necklace at preferred speed tended to produce lower mean errors than at the wrist position; and (2) at a slow speed (0.4 m/s), pedometers

  12. Laser adjustable actuators for high-accuracy positioning of micro components

    NASA Astrophysics Data System (ADS)

    Esser, Gerd; Schmidt, Michael; Dirscherl, Manfred

    2003-11-01

    High-precision adjustment of smallest optical and electronic components is increasingly recognized as one of the key issues facing micromachining technology. As even narrow production tolerances for all individual parts are often not sufficient to match the tightly specified positioning accuracies of the complete assembly, in situ adjustment techniques are gaining more and more attention. Together with research partners from industry and science, the BLZ is developing a contact-free, laser-based adjustment method which allows high-accuracy adjustment of components mounted on specifically designed actuators. The underlying mechanisms do not depend on thermal effects but on selective laser ablation of prestressed layers of actuator substrate. This way, slightest deformations or modifications of particular mechanical properties can be initiated. The method promises to be more accurate and less time consuming than thermally induced laser bending.

  13. Validation of dosimetric field matching accuracy from proton therapy using a robotic patient positioning system.

    PubMed

    Farr, Jonathan B; O'Ryan-Blair, Avril; Jesseph, Frederick; Hsi, Wen-Chien; Allgower, Chris E; Mascia, Anthony E; Thornton, Allan F; Schreuder, Andreas N

    2010-04-12

    Large area, shallow fields are well suited to proton therapy. However, due to beam production limitations, such volumes typically require multiple matched fields. This is problematic due to the relatively narrow beam penumbra at shallow depths compared to electron and photon beams. Therefore, highly accurate dose planning and delivery is required. As the dose delivery includes shifting the patient for matched fields, accuracy at the 1-2 millimeter level in patient positioning is also required. This study investigates the dosimetric accuracy of such proton field matching by an innovative robotic patient positioner system (RPPS). The dosimetric comparisons were made between treatment planning system calculations, radiographic film and ionization chamber measurements. The results indicated good agreement amongst the methods and suggest that proton field matching by a RPPS is accurate and efficient.

  14. Multi-sensor fusion with interacting multiple model filter for improved aircraft position accuracy.

    PubMed

    Cho, Taehwan; Lee, Changho; Choi, Sangbang

    2013-03-27

    The International Civil Aviation Organization (ICAO) has decided to adopt Communications, Navigation, and Surveillance/Air Traffic Management (CNS/ATM) as the 21st century standard for navigation. Accordingly, ICAO members have provided an impetus to develop related technology and build sufficient infrastructure. For aviation surveillance with CNS/ATM, Ground-Based Augmentation System (GBAS), Automatic Dependent Surveillance-Broadcast (ADS-B), multilateration (MLAT) and wide-area multilateration (WAM) systems are being established. These sensors can track aircraft positions more accurately than existing radar and can compensate for the blind spots in aircraft surveillance. In this paper, we applied a novel sensor fusion method with Interacting Multiple Model (IMM) filter to GBAS, ADS-B, MLAT, and WAM data in order to improve the reliability of the aircraft position. Results of performance analysis show that the position accuracy is improved by the proposed sensor fusion method with the IMM filter.

  15. Estimated results analysis and application of the precise point positioning based high-accuracy ionosphere delay

    NASA Astrophysics Data System (ADS)

    Wang, Shi-tai; Peng, Jun-huan

    2015-12-01

    The characterization of ionosphere delay estimated with precise point positioning is analyzed in this paper. The estimation, interpolation and application of the ionosphere delay are studied based on the processing of 24-h data from 5 observation stations. The results show that the estimated ionosphere delay is affected by the hardware delay bias from receiver so that there is a difference between the estimated and interpolated results. The results also show that the RMSs (root mean squares) are bigger, while the STDs (standard deviations) are better than 0.11 m. When the satellite difference is used, the hardware delay bias can be canceled. The interpolated satellite-differenced ionosphere delay is better than 0.11 m. Although there is a difference between the between the estimated and interpolated ionosphere delay results it cannot affect its application in single-frequency positioning and the positioning accuracy can reach cm level.

  16. Multi-Sensor Fusion with Interacting Multiple Model Filter for Improved Aircraft Position Accuracy

    PubMed Central

    Cho, Taehwan; Lee, Changho; Choi, Sangbang

    2013-01-01

    The International Civil Aviation Organization (ICAO) has decided to adopt Communications, Navigation, and Surveillance/Air Traffic Management (CNS/ATM) as the 21st century standard for navigation. Accordingly, ICAO members have provided an impetus to develop related technology and build sufficient infrastructure. For aviation surveillance with CNS/ATM, Ground-Based Augmentation System (GBAS), Automatic Dependent Surveillance-Broadcast (ADS-B), multilateration (MLAT) and wide-area multilateration (WAM) systems are being established. These sensors can track aircraft positions more accurately than existing radar and can compensate for the blind spots in aircraft surveillance. In this paper, we applied a novel sensor fusion method with Interacting Multiple Model (IMM) filter to GBAS, ADS-B, MLAT, and WAM data in order to improve the reliability of the aircraft position. Results of performance analysis show that the position accuracy is improved by the proposed sensor fusion method with the IMM filter. PMID:23535715

  17. Soccer-specific accuracy and validity of the local position measurement (LPM) system.

    PubMed

    Frencken, Wouter G P; Lemmink, Koen A P M; Delleman, Nico J

    2010-11-01

    Limited data is available on accuracy and validity of video-based, GPS and electronic tracking systems, particularly with reference to curved courses and short high intensity running activities. The main goal of this study was to assess soccer-specific accuracy and validity of the radio-frequency based local position measurement (LPM) system (1000Hz) for measuring distance and speed during walking and sprinting. Three males walked and sprinted 4 soccer-specific courses 10 times each. Distance and speed recorded by LPM were compared to actual distance and speed measured by measuring tape and timing gates. In addition, accuracy was assessed. The static accuracy (SD of the mean) is 1cm for devices put on the pitch and 2-3 cm when worn by participants. LPM underestimates actual distance (mean difference at most -1.6%). Coefficient of variation becomes larger at higher speed and increased turning angle. With regard to speed, validity correlations are high (range: 0.71-0.97). The LPM speed is significantly and systematically lower, although absolute and relative differences are small, between -0.1 km h⁻¹ (-1.3%) and -0.6 km h⁻¹ (-3.9%). The typical error of the estimate increases with increased speed, but does not increase with increased turning angle. Because the reported differences are small, we conclude that the LPM-system produces highly accurate position and speed data in static and dynamic conditions and is a valid tool for player tracking in soccer and ball team sports in general.

  18. A novel ZePoC encoder for sinusoidal signals with a predictable accuracy for an AC power standard

    NASA Astrophysics Data System (ADS)

    Vennemann, T.; Frye, T.; Liu, Z.; Kahmann, M.; Mathis, W.

    2015-11-01

    In this paper we present an analytical formulation of a Zero Position Coding (ZePoC) encoder for an AC power standard based on class-D topologies. For controlling a class-D power stage a binary signal with special spectral characteristics will be generated by this ZePoC encoder for sinusoidal signals. These spectral characteristics have a predictable accuracy within a separated baseband to keep the noise floor below a specified level. Simulation results will validate the accuracy of this novel ZePoC encoder. For a real-time implementation of the encoder on a DSP/FPGA hardware architecture a trade-off between accuracy and speed of the ZePoC algorithm has to be made. Therefore the numerical effects of different floating point formats will be analyzed.

  19. Mapping stream habitats with a global positioning system: Accuracy, precision, and comparison with traditional methods

    USGS Publications Warehouse

    Dauwalter, D.C.; Fisher, W.L.; Belt, K.C.

    2006-01-01

    We tested the precision and accuracy of the Trimble GeoXT??? global positioning system (GPS) handheld receiver on point and area features and compared estimates of stream habitat dimensions (e.g., lengths and areas of riffles and pools) that were made in three different Oklahoma streams using the GPS receiver and a tape measure. The precision of differentially corrected GPS (DGPS) points was not affected by the number of GPS position fixes (i.e., geographic location estimates) averaged per DGPS point. Horizontal error of points ranged from 0.03 to 2.77 m and did not differ with the number of position fixes per point. The error of area measurements ranged from 0.1% to 110.1% but decreased as the area increased. Again, error was independent of the number of position fixes averaged per polygon corner. The estimates of habitat lengths, widths, and areas did not differ when measured using two methods of data collection (GPS and a tape measure), nor did the differences among methods change at three stream sites with contrasting morphologies. Measuring features with a GPS receiver was up to 3.3 times faster on average than using a tape measure, although signal interference from high streambanks or overhanging vegetation occasionally limited satellite signal availability and prolonged measurements with a GPS receiver. There were also no differences in precision of habitat dimensions when mapped using a continuous versus a position fix average GPS data collection method. Despite there being some disadvantages to using the GPS in stream habitat studies, measuring stream habitats with a GPS resulted in spatially referenced data that allowed the assessment of relative habitat position and changes in habitats over time, and was often faster than using a tape measure. For most spatial scales of interest, the precision and accuracy of DGPS data are adequate and have logistical advantages when compared to traditional methods of measurement. ?? 2006 Springer Science+Business Media

  20. Genomic Prediction in Pea: Effect of Marker Density and Training Population Size and Composition on Prediction Accuracy

    PubMed Central

    Tayeh, Nadim; Klein, Anthony; Le Paslier, Marie-Christine; Jacquin, Françoise; Houtin, Hervé; Rond, Céline; Chabert-Martinello, Marianne; Magnin-Robert, Jean-Bernard; Marget, Pascal; Aubert, Grégoire; Burstin, Judith

    2015-01-01

    Pea is an important food and feed crop and a valuable component of low-input farming systems. Improving resistance to biotic and abiotic stresses is a major breeding target to enhance yield potential and regularity. Genomic selection (GS) has lately emerged as a promising technique to increase the accuracy and gain of marker-based selection. It uses genome-wide molecular marker data to predict the breeding values of candidate lines to selection. A collection of 339 genetic resource accessions (CRB339) was subjected to high-density genotyping using the GenoPea 13.2K SNP Array. Genomic prediction accuracy was evaluated for thousand seed weight (TSW), the number of seeds per plant (NSeed), and the date of flowering (BegFlo). Mean cross-environment prediction accuracies reached 0.83 for TSW, 0.68 for NSeed, and 0.65 for BegFlo. For each trait, the statistical method, the marker density, and/or the training population size and composition used for prediction were varied to investigate their effects on prediction accuracy: the effect was large for the size and composition of the training population but limited for the statistical method and marker density. Maximizing the relatedness between individuals in the training and test sets, through the CDmean-based method, significantly improved prediction accuracies. A cross-population cross-validation experiment was further conducted using the CRB339 collection as a training population set and nine recombinant inbred lines populations as test set. Prediction quality was high with mean Q2 of 0.44 for TSW and 0.59 for BegFlo. Results are discussed in the light of current efforts to develop GS strategies in pea. PMID:26635819

  1. Vehicle Position Estimation Based on Magnetic Markers: Enhanced Accuracy by Compensation of Time Delays.

    PubMed

    Byun, Yeun-Sub; Jeong, Rag-Gyo; Kang, Seok-Won

    2015-11-13

    The real-time recognition of absolute (or relative) position and orientation on a network of roads is a core technology for fully automated or driving-assisted vehicles. This paper presents an empirical investigation of the design, implementation, and evaluation of a self-positioning system based on a magnetic marker reference sensing method for an autonomous vehicle. Specifically, the estimation accuracy of the magnetic sensing ruler (MSR) in the up-to-date estimation of the actual position was successfully enhanced by compensating for time delays in signal processing when detecting the vertical magnetic field (VMF) in an array of signals. In this study, the signal processing scheme was developed to minimize the effects of the distortion of measured signals when estimating the relative positional information based on magnetic signals obtained using the MSR. In other words, the center point in a 2D magnetic field contour plot corresponding to the actual position of magnetic markers was estimated by tracking the errors between pre-defined reference models and measured magnetic signals. The algorithm proposed in this study was validated by experimental measurements using a test vehicle on a pilot network of roads. From the results, the positioning error was found to be less than 0.04 m on average in an operational test.

  2. Vehicle Position Estimation Based on Magnetic Markers: Enhanced Accuracy by Compensation of Time Delays

    PubMed Central

    Byun, Yeun-Sub; Jeong, Rag-Gyo; Kang, Seok-Won

    2015-01-01

    The real-time recognition of absolute (or relative) position and orientation on a network of roads is a core technology for fully automated or driving-assisted vehicles. This paper presents an empirical investigation of the design, implementation, and evaluation of a self-positioning system based on a magnetic marker reference sensing method for an autonomous vehicle. Specifically, the estimation accuracy of the magnetic sensing ruler (MSR) in the up-to-date estimation of the actual position was successfully enhanced by compensating for time delays in signal processing when detecting the vertical magnetic field (VMF) in an array of signals. In this study, the signal processing scheme was developed to minimize the effects of the distortion of measured signals when estimating the relative positional information based on magnetic signals obtained using the MSR. In other words, the center point in a 2D magnetic field contour plot corresponding to the actual position of magnetic markers was estimated by tracking the errors between pre-defined reference models and measured magnetic signals. The algorithm proposed in this study was validated by experimental measurements using a test vehicle on a pilot network of roads. From the results, the positioning error was found to be less than 0.04 m on average in an operational test. PMID:26580622

  3. Analysis of reliability, accuracy, sensitivity and predictive value of a subjective method to classify facial pattern in adults

    PubMed Central

    Queiroz, Gilberto Vilanova; Rino, José; de Paiva, João Batista; Capelozza, Leopoldino

    2016-01-01

    ABSTRACT Introduction: Craniofacial pattern diagnosis is vital in Orthodontics, as it influences decision-making regarding treatment options and prognosis. Capelozza Filho proposed a subjective method for facial classification comprising five patterns: I, II, III, Long Face and Short Face. Objective: To investigate the accuracy of a subjective classification method of facial patterns applied to adults. Methods: A sample consisting of 52 adults was used for this study. Frontal and lateral view photographs were taken with subjects at rest position, including frontal smile. Lateral cephalometric radiographs were organized in a PowerPoint® presentation and submitted to 20 raters. Method performance was assessed by examining reproducibility with Kappa test and calculating accuracy, sensitivity and positive predictive values, for which 70% was set as critical value. The gold standard of the classification was personally set by the author of the method. Results: Reproducibility was considered moderate (Kappa = 0.501); while accuracy, sensitivity and positive predictive values yielded similar results, but below 70%. Conclusions: The subjective method of facial classification employed in the present study still needs to have its morphological criteria improved in order to be used to discriminate the five facial patterns. PMID:28125141

  4. Accuracy of critical-temperature sensitivity coefficients predicted by multilayered composite plate theories

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K.; Burton, Scott

    1992-01-01

    An assessment is made of the accuracy of the critical-temperature sensitivity coefficients of multilayered plates predicted by different modeling approaches, based on two-dimensional shear-deformation theories. The sensitivity coefficients considered measure the sensitivity of the critical temperatures to variations in different lamination and material parameters of the plate. The standard of comparison is taken to be the sensitivity coefficients obtained by the three-dimensional theory of thermoelasticity. Numerical studies are presented showing the effects of variation in the geometric and lamination parameters of the plate on the accuracy of both the sensitivity coefficients and the critical temperatures predicted by the different modeling approaches.

  5. Predicting transition to the supine sleep position in preterm infants.

    PubMed

    McMullen, Sherri L; Carey, Mary G

    2014-01-01

    The purpose of this secondary analysis was to determine what factors predict the transition of preterm infants to the supine sleep position prior to hospital discharge (N = 286). The supine position reduces the risk of sudden infant death syndrome. Factors found to predict a greater than 1-week transition to the supine sleep position were hospital policy (P < .001), gestational age (P < .001), and birth weight (P < .01). Transition to the supine position during hospitalization potentially reduces the risk of preterm infants being placed in nonsupine positions after hospitalization and, ultimately, the risk of untimely death by sudden infant death syndrome.

  6. High accuracy integrated global positioning system/inertial navigation system LDRD: Final report

    SciTech Connect

    Owen, T.E.; Meindl, M.A.; Fellerhoff, J.R.

    1997-03-01

    This report contains the results of a Sandia National Laboratories Directed Research and Development (LDRD) program to investigate the integration of Global Positioning System (GPS) and inertial navigation system (INS) technologies toward the goal of optimizing the navigational accuracy of the combined GPSANS system. The approach undertaken is to integrate the data from an INS, which has long term drifts, but excellent short term accuracy, with GPS carrier phase signal information, which is accurate to the sub-centimeter level, but requires continuous tracking of the GPS signals. The goal is to maintain a sub-meter accurate navigation solution while the vehicle is in motion by using the GPS measurements to estimate the INS navigation errors and then using the refined INS data to aid the GPS carrier phase cycle slip detection and correction and bridge dropouts in the GPS data. The work was expanded to look at GPS-based attitude determination, using multiple GPS receivers and antennas on a single platform, as a possible navigation aid. Efforts included not only the development of data processing algorithms and software, but also the collection and analysis of GPS and INS flight data aboard a Twin Otter aircraft. Finally, the application of improved navigation system accuracy to synthetic aperture radar (SAR) target location is examined.

  7. Even modest prediction accuracy of genomic models can have large clinical utility

    PubMed Central

    Dhurandhar, Emily J.; Vazquez, Ana I.; Argyropoulos, George A.; Allison, David B.

    2014-01-01

    Whole Genome Prediction (WGP) jointly fits thousands of SNPs into a regression model to yield estimates for the contribution of markers to the overall variance of a particular trait, and for their associations with that trait. To date, WGP has offered only modest prediction accuracy, but in some cases even modest prediction accuracy may be useful. We provide an illustration of this using a theoretical simulation that used WGP to predict weight loss after bariatric surgery with moderate accuracy (R2 = 0.07) to assess the clinical utility of WGP despite these limitations. Prevention of Type 2 Diabetes (T2DM) post-surgery was considered the major outcome. Treating only patients above predefined threshold of predicted weight loss in our simulation, in the realistic context of finite resources for the surgery, significantly reduced lifetime risk of T2DM in the treatable population by selecting those most likely to succeed. Thus, our example illustrates how WGP may be clinically useful in some situations, and even with moderate accuracy, may provide a clear path for turning personalized medicine from theory to reality. PMID:25506355

  8. Accuracy of sonographic fetal gender determination: predictions made by sonographers during routine obstetric ultrasound scans

    PubMed Central

    Pollard, Karen; Garbett, Ian

    2015-01-01

    Abstract Objectives: The purpose of this study was to determine the accuracy of sonographer predictions of fetal gender during routine ultrasounds. Primarily, the study sought to investigate the accuracy of predictions made in the first trimester, as requests from parents wanting to know the gender of their fetus at this early scan are becoming increasingly common. Second and third trimester fetuses were included in the study to confirm the accuracy of later predictions. In addition, the mother's decision to know the gender was recorded to determine the prevalence of women wanting prenatal predictions. Methods: A prospective, cross sectional study was conducted in a specialist private obstetric practice in the Illawarra, NSW. A total of 640 fetuses across three trimesters were examined collectively by seven sonographers. Fetal gender was predicted using the sagittal plane only in the first trimester and either the sagittal or transverse plane in later trimesters. Phenotypic gender confirmation was obtained from hospital records or direct telephone contact with women postnatally. Results: Results confirmed 100% accuracy in predictions made after 14 weeks gestation. The overall success rate in the first trimester group (11–14 weeks) was 75%. When excluding those scans where a prediction could not be made, success rates increased to 91%. Results were less accurate for fetuses younger than 12 weeks, with an overall success rate of 54%. Male fetuses under 13 weeks were more likely to have gender incorrectly or unable to be assigned. After 13 weeks, success rates for correctly predicting males exceeded that of female fetuses. Statistical differences were noted in the success rates of individual sonographers. Sixty seven percent of women were in favour of knowing fetal gender from ultrasound. Publicly insured women were more likely to request gender disclosure than privately insured women. Conclusions: Sonographic gender determination provides high success rates in the

  9. Accuracy assessment of the ERP prediction method based on analysis of 100-year ERP series

    NASA Astrophysics Data System (ADS)

    Malkin, Z.; Tissen, V. M.

    2012-12-01

    A new method has been developed at the Siberian Research Institute of Metrology (SNIIM) for highly accurate prediction of UT1 and Pole motion (PM). In this study, a detailed comparison was made of real-time UT1 predictions made in 2006-2011 and PMpredictions made in 2009-2011making use of the SNIIM method with simultaneous predictions computed at the International Earth Rotation and Reference Systems Service (IERS), USNO. Obtained results have shown that proposed method provides better accuracy at different prediction lengths.

  10. The devil is in the specificity: the negative effect of prediction specificity on prediction accuracy.

    PubMed

    Yoon, Song-Oh; Suk, Kwanho; Goo, Jin Kyung; Lee, Jiheon; Lee, Seon Min

    2013-07-01

    In the research reported here, we proposed and demonstrated the prediction-specificity effect, which states that people's prediction of the general outcome of an event (e.g., the winner of a soccer match) is less accurate when the prediction question is framed in a more specific manner (e.g., guessing the score) rather than in a less specific manner (e.g., guessing the winner). We demonstrated this effect by examining people's predictions on actual sports games both in field and laboratory studies. In Study 1, the analysis of 19 billion bets from a commercial sports-betting business provided evidence for the effect of prediction specificity. This effect was replicated in three controlled laboratory studies, in which participants predicted the outcomes of a series of soccer matches. Furthermore, the negative effect of prediction specificity was mediated by participants' underweighting of important holistic information during decision making.

  11. Accuracy of relative positioning by interferometry with GPS Double-blind test results

    NASA Technical Reports Server (NTRS)

    Counselman, C. C., III; Gourevitch, S. A.; Herring, T. A.; King, B. W.; Shapiro, I. I.; Cappallo, R. J.; Rogers, A. E. E.; Whitney, A. R.; Greenspan, R. L.; Snyder, R. E.

    1983-01-01

    MITES (Miniature Interferometer Terminals for Earth Surveying) observations conducted on December 17 and 29, 1980, are analyzed. It is noted that the time span of the observations used on each day was 78 minutes, during which five satellites were always above 20 deg elevation. The observations are analyzed to determine the intersite position vectors by means of the algorithm described by Couselman and Gourevitch (1981). The average of the MITES results from the two days is presented. The rms differences between the two determinations of the components of the three vectors, which were about 65, 92, and 124 m long, were 8 mm for the north, 3 mm for the east, and 6 mm for the vertical. It is concluded that, at least for short distances, relative positioning by interferometry with GPS can be done reliably with subcentimeter accuracy.

  12. Probability of criminal acts of violence: a test of jury predictive accuracy.

    PubMed

    Reidy, Thomas J; Sorensen, Jon R; Cunningham, Mark D

    2013-01-01

    The ability of capital juries to accurately predict future prison violence at the sentencing phase of aggravated murder trials was examined through retrospective review of the disciplinary records of 115 male inmates sentenced to either life (n = 65) or death (n = 50) in Oregon from 1985 through 2008, with a mean post-conviction time at risk of 15.3 years. Violent prison behavior was completely unrelated to predictions made by capital jurors, with bidirectional accuracy simply reflecting the base rate of assaultive misconduct in the group. Rejection of the special issue predicting future violence enjoyed 90% accuracy. Conversely, predictions that future violence was probable had 90% error rates. More than 90% of the assaultive rule violations committed by these offenders resulted in no harm or only minor injuries.

  13. Motor system contribution to action prediction: Temporal accuracy depends on motor experience.

    PubMed

    Stapel, Janny C; Hunnius, Sabine; Meyer, Marlene; Bekkering, Harold

    2016-03-01

    Predicting others' actions is essential for well-coordinated social interactions. In two experiments including an infant population, this study addresses to what extent motor experience of an observer determines prediction accuracy for others' actions. Results show that infants who were proficient crawlers but inexperienced walkers predicted crawling more accurately than walking, whereas age groups mastering both skills (i.e. toddlers and adults) were equally accurate in predicting walking and crawling. Regardless of experience, human movements were predicted more accurately by all age groups than non-human movement control stimuli. This suggests that for predictions to be accurate, the observed act needs to be established in the motor repertoire of the observer. Through the acquisition of new motor skills, we also become better at predicting others' actions. The findings thus stress the relevance of motor experience for social-cognitive development.

  14. Effect of Traffic Position Accuracy for Conducting Safe Airport Surface Operations

    NASA Technical Reports Server (NTRS)

    Jones, Denise R.; Prinzel, Lawrence J., III; Bailey, Randall E.; Arthur, Jarvis J., III; Barnes, James R.

    2014-01-01

    The Next Generation Air Transportation System (NextGen) concept proposes many revolutionary operational concepts and technologies, such as display of traffic information and movements, airport moving maps (AMM), and proactive alerts of runway incursions and surface traffic conflicts, to deliver an overall increase in system capacity and safety. A piloted simulation study was conducted at the National Aeronautics and Space Administration (NASA) Langley Research Center to evaluate the ability to conduct safe and efficient airport surface operations while utilizing an AMM displaying traffic of various position accuracies as well as the effect of traffic position accuracy on airport conflict detection and resolution (CD&R) capability. Nominal scenarios and off-nominal conflict scenarios were conducted using 12 airline crews operating in a simulated Memphis International Airport terminal environment. The data suggest that all traffic should be shown on the airport moving map, whether qualified or unqualified, and conflict detection and resolution technologies provide significant safety benefits. Despite the presence of traffic information on the map, collisions or near collisions still occurred; when indications or alerts were generated in these same scenarios, the incidences were averted.

  15. Using genomic prediction to characterize environments and optimize prediction accuracy in applied breeding data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simulation and empirical studies of genomic selection (GS) show accuracies sufficient to generate rapid annual genetic gains. It also shifts the focus from the evaluation of lines to the evaluation of alleles. Consequently, new methods should be developed to optimize the use of large historic multi-...

  16. An Analysis of Debris Orbit Prediction Accuracy from Short-arc Orbit Determination Using Optical and Laser Tracking Data

    NASA Astrophysics Data System (ADS)

    Bennett, J.; Sang, J.; Smith, C.; Zhang, K.

    2014-09-01

    In this paper results are presented from a short-arc orbit determination study using optical and laser tracking data from the Space Debris Tracking System located at Mount Stromlo, Australia. Fifteen low-Earth orbit debris objects were considered in the study with perigee altitudes in the range 550850 km. In most cases, a 2-day orbit determination was considered using 2 passes of optical and 2 passes of laser tracking data. A total of 33 1-day and 26 2-day orbit prediction cases were compared with residuals obtained by comparing the orbit prediction with subsequent tracking data. A comparison was made between the orbit prediction accuracies for 2 orbit determination variants: (1) Entire passes are used during the orbit determination process; (2) Only 5 seconds is used from the beginning of each pass. Overall, the short-arc orbit determination results in (slightly) worse 1 and 2 day orbit prediction accuracies when compared to using the full observation arcs; however, the savings in tracking load outweighs the reduction in accuracy. If the optical or laser data is left out of the 5-second pass orbit determination process, most cases diverged which shows the importance of 3-dimenional positioning. Two-line element data was used to constrain the orbit determination process resulting in better convergence rates, but the resulting orbit prediction accuracy was much worse. The results have important implications for an optical and laser debris tracking network with potential savings in tracking load. An experimental study will be needed to verify this statement.

  17. Seed Quality Traits Can Be Predicted with High Accuracy in Brassica napus Using Genomic Data

    PubMed Central

    Liu, Peifa; Shi, Lei; Wang, Xiaohua; Wang, Meng; Meng, Jinling; Reif, Jochen Christoph

    2016-01-01

    Improving seed oil yield and quality are central targets in rapeseed (Brassica napus) breeding. The primary goal of our study was to examine and compare the potential and the limits of marker-assisted selection and genome-wide prediction of six important seed quality traits of B. napus. Our study is based on a bi-parental population comprising 202 doubled haploid lines and a diverse validation set including 117 B. napus inbred lines derived from interspecific crosses between B. rapa and B. carinata. We used phenotypic data for seed oil, protein, erucic acid, linolenic acid, stearic acid, and glucosinolate content. All lines were genotyped with a 60k SNP array. We performed five-fold cross-validations in combination with linkage mapping and four genome-wide prediction approaches in the bi-parental population. Quantitative trait loci (QTL) with large effects were detected for erucic acid, stearic acid, and glucosinolate content, blazing the trail for marker-assisted selection. Despite substantial differences in the complexity of the genetic architecture of the six traits, genome-wide prediction models had only minor impacts on the prediction accuracies. We evaluated the effects of training population size, marker density and phenotyping intensity on the prediction accuracy. The prediction accuracy in the independent and genetically very distinct validation set still amounted to 0.14 for protein content and 0.17 for oil content reflecting the utility of the developed calibration models even in very diverse backgrounds. PMID:27880793

  18. Reduction in accuracy of genomic prediction for ordered categorical data compared to continuous observations

    PubMed Central

    2014-01-01

    Background Accuracy of genomic prediction depends on number of records in the training population, heritability, effective population size, genetic architecture, and relatedness of training and validation populations. Many traits have ordered categories including reproductive performance and susceptibility or resistance to disease. Categorical scores are often recorded because they are easier to obtain than continuous observations. Bayesian linear regression has been extended to the threshold model for genomic prediction. The objective of this study was to quantify reductions in accuracy for ordinal categorical traits relative to continuous traits. Methods Efficiency of genomic prediction was evaluated for heritabilities of 0.10, 0.25 or 0.50. Phenotypes were simulated for 2250 purebred animals using 50 QTL selected from actual 50k SNP (single nucleotide polymorphism) genotypes giving a proportion of causal to total loci of.0001. A Bayes C π threshold model simultaneously fitted all 50k markers except those that represented QTL. Estimated SNP effects were utilized to predict genomic breeding values in purebred (n = 239) or multibreed (n = 924) validation populations. Correlations between true and predicted genomic merit in validation populations were used to assess predictive ability. Results Accuracies of genomic estimated breeding values ranged from 0.12 to 0.66 for purebred and from 0.04 to 0.53 for multibreed validation populations based on Bayes C π linear model analysis of the simulated underlying variable. Accuracies for ordinal categorical scores analyzed by the Bayes C π threshold model were 20% to 50% lower and ranged from 0.04 to 0.55 for purebred and from 0.01 to 0.44 for multibreed validation populations. Analysis of ordinal categorical scores using a linear model resulted in further reductions in accuracy. Conclusions Threshold traits result in markedly lower accuracy than a linear model on the underlying variable. To achieve an accuracy equal or

  19. Phishtest: Measuring the Impact of Email Headers on the Predictive Accuracy of Machine Learning Techniques

    ERIC Educational Resources Information Center

    Tout, Hicham

    2013-01-01

    The majority of documented phishing attacks have been carried by email, yet few studies have measured the impact of email headers on the predictive accuracy of machine learning techniques in detecting email phishing attacks. Research has shown that the inclusion of a limited subset of email headers as features in training machine learning…

  20. An Information-Processing Analysis of Children's Accuracy in Predicting the Appearance of Rotated Stimuli.

    ERIC Educational Resources Information Center

    Rosser, Rosemary A.; And Others

    1984-01-01

    The ability of 40 children four and five years of age to discriminate reflections and rotations of visual stimuli was examined in a kinetic imagery task. Results revealed that prediction accuracy was associated with the existence of orientation markers on the stimuli, as well as age, sex, type of discrimination, and several interactions among the…

  1. Predictive Validity and Accuracy of Oral Reading Fluency for English Learners

    ERIC Educational Resources Information Center

    Vanderwood, Michael L.; Tung, Catherine Y.; Checca, C. Jason

    2014-01-01

    The predictive validity and accuracy of an oral reading fluency (ORF) measure for a statewide assessment in English language arts was examined for second-grade native English speakers (NESs) and English learners (ELs) with varying levels of English proficiency. In addition to comparing ELs with native English speakers, the impact of English…

  2. Predicting fish species distribution in estuaries: Influence of species' ecology in model accuracy

    NASA Astrophysics Data System (ADS)

    França, Susana; Cabral, Henrique N.

    2016-10-01

    Current threats to biodiversity, combined with limited data availability, have made for species distribution models (SDMs) to be increasingly used due to their ability to predict species' potential distribution, by relating species occurrence with environmental estimates. Often used in ecology, conservation biology and environmental management, SDMs have been informing conservation strategies, and thus it is becoming crucial to understand how trustworthy their predictions are. Uncertainty in model predictions is expected, but knowing the origin of prediction errors may help reducing it. Indeed, uncertainty may be related not only with data quality and the modelling algorithm used, but also with species ecological characteristics. To investigate whether the performance of SDM's may vary with species' ecological characteristics, distribution models for 21 fish species occurring in estuaries from the Portuguese coast were examined. These models were built at two distinct spatial resolutions and seven environmental explanatory variables were used as predictors. SDMs' accuracy was assessed with the area under the curve (AUC) of receiver operating characteristics (ROC) plots, sensitivity and specificity. Relationships between each measure of accuracy and species ecological characteristics were then examined. SDMs of the fish species presented small differences between the considered scales, and predictors as latitude, temperature and salinity were often selected at both scales. Measures of model accuracy presented differences between species and scales, but generally higher accuracy was obtained at smaller spatial scales. Among the ecological traits tested, species feeding mode and estuarine use functional groups were the most influential on the performance of distribution models. Habitat tolerance (number of habitat types frequented), species abundance, body size and spawning period also showed some effect. This analyses will contribute to distinguish, based on species

  3. Millimetre Level Accuracy GNSS Positioning with the Blind Adaptive Beamforming Method in Interference Environments.

    PubMed

    Daneshmand, Saeed; Marathe, Thyagaraja; Lachapelle, Gérard

    2016-10-31

    The use of antenna arrays in Global Navigation Satellite System (GNSS) applications is gaining significant attention due to its superior capability to suppress both narrowband and wideband interference. However, the phase distortions resulting from array processing may limit the applicability of these methods for high precision applications using carrier phase based positioning techniques. This paper studies the phase distortions occurring with the adaptive blind beamforming method in which satellite angle of arrival (AoA) information is not employed in the optimization problem. To cater to non-stationary interference scenarios, the array weights of the adaptive beamformer are continuously updated. The effects of these continuous updates on the tracking parameters of a GNSS receiver are analyzed. The second part of this paper focuses on reducing the phase distortions during the blind beamforming process in order to allow the receiver to perform carrier phase based positioning by applying a constraint on the structure of the array configuration and by compensating the array uncertainties. Limitations of the previous methods are studied and a new method is proposed that keeps the simplicity of the blind beamformer structure and, at the same time, reduces tracking degradations while achieving millimetre level positioning accuracy in interference environments. To verify the applicability of the proposed method and analyze the degradations, array signals corresponding to the GPS L1 band are generated using a combination of hardware and software simulators. Furthermore, the amount of degradation and performance of the proposed method under different conditions are evaluated based on Monte Carlo simulations.

  4. Millimetre Level Accuracy GNSS Positioning with the Blind Adaptive Beamforming Method in Interference Environments

    PubMed Central

    Daneshmand, Saeed; Marathe, Thyagaraja; Lachapelle, Gérard

    2016-01-01

    The use of antenna arrays in Global Navigation Satellite System (GNSS) applications is gaining significant attention due to its superior capability to suppress both narrowband and wideband interference. However, the phase distortions resulting from array processing may limit the applicability of these methods for high precision applications using carrier phase based positioning techniques. This paper studies the phase distortions occurring with the adaptive blind beamforming method in which satellite angle of arrival (AoA) information is not employed in the optimization problem. To cater to non-stationary interference scenarios, the array weights of the adaptive beamformer are continuously updated. The effects of these continuous updates on the tracking parameters of a GNSS receiver are analyzed. The second part of this paper focuses on reducing the phase distortions during the blind beamforming process in order to allow the receiver to perform carrier phase based positioning by applying a constraint on the structure of the array configuration and by compensating the array uncertainties. Limitations of the previous methods are studied and a new method is proposed that keeps the simplicity of the blind beamformer structure and, at the same time, reduces tracking degradations while achieving millimetre level positioning accuracy in interference environments. To verify the applicability of the proposed method and analyze the degradations, array signals corresponding to the GPS L1 band are generated using a combination of hardware and software simulators. Furthermore, the amount of degradation and performance of the proposed method under different conditions are evaluated based on Monte Carlo simulations. PMID:27809252

  5. Integrated Strategy Improves the Prediction Accuracy of miRNA in Large Dataset

    PubMed Central

    Lipps, David; Devineni, Sree

    2016-01-01

    MiRNAs are short non-coding RNAs of about 22 nucleotides, which play critical roles in gene expression regulation. The biogenesis of miRNAs is largely determined by the sequence and structural features of their parental RNA molecules. Based on these features, multiple computational tools have been developed to predict if RNA transcripts contain miRNAs or not. Although being very successful, these predictors started to face multiple challenges in recent years. Many predictors were optimized using datasets of hundreds of miRNA samples. The sizes of these datasets are much smaller than the number of known miRNAs. Consequently, the prediction accuracy of these predictors in large dataset becomes unknown and needs to be re-tested. In addition, many predictors were optimized for either high sensitivity or high specificity. These optimization strategies may bring in serious limitations in applications. Moreover, to meet continuously raised expectations on these computational tools, improving the prediction accuracy becomes extremely important. In this study, a meta-predictor mirMeta was developed by integrating a set of non-linear transformations with meta-strategy. More specifically, the outputs of five individual predictors were first preprocessed using non-linear transformations, and then fed into an artificial neural network to make the meta-prediction. The prediction accuracy of meta-predictor was validated using both multi-fold cross-validation and independent dataset. The final accuracy of meta-predictor in newly-designed large dataset is improved by 7% to 93%. The meta-predictor is also proved to be less dependent on datasets, as well as has refined balance between sensitivity and specificity. This study has two folds of importance: First, it shows that the combination of non-linear transformations and artificial neural networks improves the prediction accuracy of individual predictors. Second, a new miRNA predictor with significantly improved prediction accuracy

  6. Improving Prediction Accuracy for WSN Data Reduction by Applying Multivariate Spatio-Temporal Correlation

    PubMed Central

    Carvalho, Carlos; Gomes, Danielo G.; Agoulmine, Nazim; de Souza, José Neuman

    2011-01-01

    This paper proposes a method based on multivariate spatial and temporal correlation to improve prediction accuracy in data reduction for Wireless Sensor Networks (WSN). Prediction of data not sent to the sink node is a technique used to save energy in WSNs by reducing the amount of data traffic. However, it may not be very accurate. Simulations were made involving simple linear regression and multiple linear regression functions to assess the performance of the proposed method. The results show a higher correlation between gathered inputs when compared to time, which is an independent variable widely used for prediction and forecasting. Prediction accuracy is lower when simple linear regression is used, whereas multiple linear regression is the most accurate one. In addition to that, our proposal outperforms some current solutions by about 50% in humidity prediction and 21% in light prediction. To the best of our knowledge, we believe that we are probably the first to address prediction based on multivariate correlation for WSN data reduction. PMID:22346626

  7. Accuracy of Genomic Prediction in Switchgrass (Panicum virgatum L.) Improved by Accounting for Linkage Disequilibrium

    PubMed Central

    Ramstein, Guillaume P.; Evans, Joseph; Kaeppler, Shawn M.; Mitchell, Robert B.; Vogel, Kenneth P.; Buell, C. Robin; Casler, Michael D.

    2016-01-01

    Switchgrass is a relatively high-yielding and environmentally sustainable biomass crop, but further genetic gains in biomass yield must be achieved to make it an economically viable bioenergy feedstock. Genomic selection (GS) is an attractive technology to generate rapid genetic gains in switchgrass, and meet the goals of a substantial displacement of petroleum use with biofuels in the near future. In this study, we empirically assessed prediction procedures for genomic selection in two different populations, consisting of 137 and 110 half-sib families of switchgrass, tested in two locations in the United States for three agronomic traits: dry matter yield, plant height, and heading date. Marker data were produced for the families’ parents by exome capture sequencing, generating up to 141,030 polymorphic markers with available genomic-location and annotation information. We evaluated prediction procedures that varied not only by learning schemes and prediction models, but also by the way the data were preprocessed to account for redundancy in marker information. More complex genomic prediction procedures were generally not significantly more accurate than the simplest procedure, likely due to limited population sizes. Nevertheless, a highly significant gain in prediction accuracy was achieved by transforming the marker data through a marker correlation matrix. Our results suggest that marker-data transformations and, more generally, the account of linkage disequilibrium among markers, offer valuable opportunities for improving prediction procedures in GS. Some of the achieved prediction accuracies should motivate implementation of GS in switchgrass breeding programs. PMID:26869619

  8. Numerical simulation of turbulence flow in a Kaplan turbine -Evaluation on turbine performance prediction accuracy-

    NASA Astrophysics Data System (ADS)

    Ko, P.; Kurosawa, S.

    2014-03-01

    The understanding and accurate prediction of the flow behaviour related to cavitation and pressure fluctuation in a Kaplan turbine are important to the design work enhancing the turbine performance including the elongation of the operation life span and the improvement of turbine efficiency. In this paper, high accuracy turbine and cavitation performance prediction method based on entire flow passage for a Kaplan turbine is presented and evaluated. Two-phase flow field is predicted by solving Reynolds-Averaged Navier-Stokes equations expressed by volume of fluid method tracking the free surface and combined with Reynolds Stress model. The growth and collapse of cavitation bubbles are modelled by the modified Rayleigh-Plesset equation. The prediction accuracy is evaluated by comparing with the model test results of Ns 400 Kaplan model turbine. As a result that the experimentally measured data including turbine efficiency, cavitation performance, and pressure fluctuation are accurately predicted. Furthermore, the cavitation occurrence on the runner blade surface and the influence to the hydraulic loss of the flow passage are discussed. Evaluated prediction method for the turbine flow and performance is introduced to facilitate the future design and research works on Kaplan type turbine.

  9. Breeding Jatropha curcas by genomic selection: A pilot assessment of the accuracy of predictive models

    PubMed Central

    de Azevedo Peixoto, Leonardo; Laviola, Bruno Galvêas; Alves, Alexandre Alonso; Rosado, Tatiana Barbosa; Bhering, Leonardo Lopes

    2017-01-01

    Genomic wide selection is a promising approach for improving the selection accuracy in plant breeding, particularly in species with long life cycles, such as Jatropha. Therefore, the objectives of this study were to estimate the genetic parameters for grain yield (GY) and the weight of 100 seeds (W100S) using restricted maximum likelihood (REML); to compare the performance of GWS methods to predict GY and W100S; and to estimate how many markers are needed to train the GWS model to obtain the maximum accuracy. Eight GWS models were compared in terms of predictive ability. The impact that the marker density had on the predictive ability was investigated using a varying number of markers, from 2 to 1,248. Because the genetic variance between evaluated genotypes was significant, it was possible to obtain selection gain. All of the GWS methods tested in this study can be used to predict GY and W100S in Jatropha. A training model fitted using 1,000 and 800 markers is sufficient to capture the maximum genetic variance and, consequently, maximum prediction ability of GY and W100S, respectively. This study demonstrated the applicability of genome-wide prediction to identify useful genetic sources of GY and W100S for Jatropha breeding. Further research is needed to confirm the applicability of the proposed approach to other complex traits. PMID:28296913

  10. Breeding Jatropha curcas by genomic selection: A pilot assessment of the accuracy of predictive models.

    PubMed

    Azevedo Peixoto, Leonardo de; Laviola, Bruno Galvêas; Alves, Alexandre Alonso; Rosado, Tatiana Barbosa; Bhering, Leonardo Lopes

    2017-01-01

    Genomic wide selection is a promising approach for improving the selection accuracy in plant breeding, particularly in species with long life cycles, such as Jatropha. Therefore, the objectives of this study were to estimate the genetic parameters for grain yield (GY) and the weight of 100 seeds (W100S) using restricted maximum likelihood (REML); to compare the performance of GWS methods to predict GY and W100S; and to estimate how many markers are needed to train the GWS model to obtain the maximum accuracy. Eight GWS models were compared in terms of predictive ability. The impact that the marker density had on the predictive ability was investigated using a varying number of markers, from 2 to 1,248. Because the genetic variance between evaluated genotypes was significant, it was possible to obtain selection gain. All of the GWS methods tested in this study can be used to predict GY and W100S in Jatropha. A training model fitted using 1,000 and 800 markers is sufficient to capture the maximum genetic variance and, consequently, maximum prediction ability of GY and W100S, respectively. This study demonstrated the applicability of genome-wide prediction to identify useful genetic sources of GY and W100S for Jatropha breeding. Further research is needed to confirm the applicability of the proposed approach to other complex traits.

  11. Accuracy of three-dimensional soft tissue predictions in orthognathic surgery after Le Fort I advancement osteotomies.

    PubMed

    Ullah, R; Turner, P J; Khambay, B S

    2015-02-01

    Prediction of postoperative facial appearance after orthognathic surgery can be used for communication, managing patients' expectations,avoiding postoperative dissatisfaction and exploring different treatment options. We have assessed the accuracy of 3dMD Vultus in predicting the final 3-dimensional soft tissue facial morphology after Le Fort I advancement osteotomy. We retrospectively studied 13 patients who were treated with a Le Fort I advancement osteotomy alone. We used routine cone-beam computed tomographic (CT) images taken immediately before and a minimum of 6 months after operation, and 3dMD Vultus to virtually reposition the preoperative maxilla and mandible in their post operative positions to generate a prediction of what the soft tissue would look like. Segmented anatomical areas of the predicted mesh were then compared with the actual soft tissue. The means of the absolute distance between the 90th percentile of the mesh points for each region were calculated, and a one-sample Student's t test was used to calculate if the difference differed significantly from 3 mm.The differences in the mean absolute distances between the actual soft tissue and the prediction were significantly below 3 mm for all segmented anatomical areas (p < 0.001), and ranged from 0.65 mm (chin) to 1.17 mm (upper lip). 3dMD Vultus produces clinically satisfactory 3-dimensional facial soft tissue predictions after Le Fort I advancement osteotomy. The mass-spring model for prediction seems to be able to predict the position of the lip and chin, but its ability to predict nasal and paranasal areas could be improved.

  12. Accuracy and reliability of multi-GNSS real-time precise positioning: GPS, GLONASS, BeiDou, and Galileo

    NASA Astrophysics Data System (ADS)

    Li, Xingxing; Ge, Maorong; Dai, Xiaolei; Ren, Xiaodong; Fritsche, Mathias; Wickert, Jens; Schuh, Harald

    2015-06-01

    In this contribution, we present a GPS+GLONASS+BeiDou+Galileo four-system model to fully exploit the observations of all these four navigation satellite systems for real-time precise orbit determination, clock estimation and positioning. A rigorous multi-GNSS analysis is performed to achieve the best possible consistency by processing the observations from different GNSS together in one common parameter estimation procedure. Meanwhile, an efficient multi-GNSS real-time precise positioning service system is designed and demonstrated by using the multi-GNSS Experiment, BeiDou Experimental Tracking Network, and International GNSS Service networks including stations all over the world. The statistical analysis of the 6-h predicted orbits show that the radial and cross root mean square (RMS) values are smaller than 10 cm for BeiDou and Galileo, and smaller than 5 cm for both GLONASS and GPS satellites, respectively. The RMS values of the clock differences between real-time and batch-processed solutions for GPS satellites are about 0.10 ns, while the RMS values for BeiDou, Galileo and GLONASS are 0.13, 0.13 and 0.14 ns, respectively. The addition of the BeiDou, Galileo and GLONASS systems to the standard GPS-only processing, reduces the convergence time almost by 70 %, while the positioning accuracy is improved by about 25 %. Some outliers in the GPS-only solutions vanish when multi-GNSS observations are processed simultaneous. The availability and reliability of GPS precise positioning decrease dramatically as the elevation cutoff increases. However, the accuracy of multi-GNSS precise point positioning (PPP) is hardly decreased and few centimeter are still achievable in the horizontal components even with 40 elevation cutoff. At 30 and 40 elevation cutoffs, the availability rates of GPS-only solution drop significantly to only around 70 and 40 %, respectively. However, multi-GNSS PPP can provide precise position estimates continuously (availability rate is more than 99

  13. Openstage: A Low-Cost Motorized Microscope Stage with Sub-Micron Positioning Accuracy

    PubMed Central

    Campbell, Robert A. A.; Eifert, Robert W.; Turner, Glenn C.

    2014-01-01

    Recent progress in intracellular calcium sensors and other fluorophores has promoted the widespread adoption of functional optical imaging in the life sciences. Home-built multiphoton microscopes are easy to build, highly customizable, and cost effective. For many imaging applications a 3-axis motorized stage is critical, but commercially available motorization hardware (motorized translators, controller boxes, etc) are often very expensive. Furthermore, the firmware on commercial motor controllers cannot easily be altered and is not usually designed with a microscope stage in mind. Here we describe an open-source motorization solution that is simple to construct, yet far cheaper and more customizable than commercial offerings. The cost of the controller and motorization hardware are under $1000. Hardware costs are kept low by replacing linear actuators with high quality stepper motors. Electronics are assembled from commonly available hobby components, which are easy to work with. Here we describe assembly of the system and quantify the positioning accuracy of all three axes. We obtain positioning repeatability of the order of in X/Y and in Z. A hand-held control-pad allows the user to direct stage motion precisely over a wide range of speeds ( to ), rapidly store and return to different locations, and execute “jumps” of a fixed size. In addition, the system can be controlled from a PC serial port. Our “OpenStage” controller is sufficiently flexible that it could be used to drive other devices, such as micro-manipulators, with minimal modifications. PMID:24586468

  14. Influence of both angle and position error of pentaprism on accuracy of pentaprism scanning system

    NASA Astrophysics Data System (ADS)

    Xu, Kun; Han, Sen; Zhang, Qiyuan; Wu, Quanying

    2014-11-01

    Pentaprism scanning system has been widely used in the measurement of large flat and wavefront, based on its property that the deviated beam will have no motion in the pitch direction. But the manufacturing and position errors of pentaprisms will bring error to the measurement and so a good error analysis method is indispensable. In this paper, we propose a new method of building mathematic models of pentaprism and through which the size and angle errors of a pentaprism can be put into the model as parameters. 4 size parameters are selected to determine the size and 11 angle parameters are selected to determine the angles of a pentaprism. Yaw, Roll and Pitch are used to describe the position error of a pentaprism and an autocollimator. A pentaprism scanning system of wavefront test is simulated by ray tracing using matlab. We design a method of separating the constant from the measurement results which will improve the measurement accuracy and analyze the system error by Monte Carlo method. This method is simple, rapid, accurate and convenient for computer programming.

  15. Empirical Accuracies of U.S. Space Surveillance Network Reentry Predictions

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.

    2008-01-01

    The U.S. Space Surveillance Network (SSN) issues formal satellite reentry predictions for objects which have the potential for generating debris which could pose a hazard to people or property on Earth. These prognostications, known as Tracking and Impact Prediction (TIP) messages, are nominally distributed at daily intervals beginning four days prior to the anticipated reentry and several times during the final 24 hours in orbit. The accuracy of these messages depends on the nature of the satellite s orbit, the characteristics of the space vehicle, solar activity, and many other factors. Despite the many influences on the time and the location of reentry, a useful assessment of the accuracies of TIP messages can be derived and compared with the official accuracies included with each TIP message. This paper summarizes the results of a study of numerous uncontrolled reentries of spacecraft and rocket bodies from nearly circular orbits over a span of several years. Insights are provided into the empirical accuracies and utility of SSN TIP messages.

  16. Increased genomic prediction accuracy in wheat breeding through spatial adjustment of field trial data.

    PubMed

    Lado, Bettina; Matus, Ivan; Rodríguez, Alejandra; Inostroza, Luis; Poland, Jesse; Belzile, François; del Pozo, Alejandro; Quincke, Martín; Castro, Marina; von Zitzewitz, Jarislav

    2013-12-09

    In crop breeding, the interest of predicting the performance of candidate cultivars in the field has increased due to recent advances in molecular breeding technologies. However, the complexity of the wheat genome presents some challenges for applying new technologies in molecular marker identification with next-generation sequencing. We applied genotyping-by-sequencing, a recently developed method to identify single-nucleotide polymorphisms, in the genomes of 384 wheat (Triticum aestivum) genotypes that were field tested under three different water regimes in Mediterranean climatic conditions: rain-fed only, mild water stress, and fully irrigated. We identified 102,324 single-nucleotide polymorphisms in these genotypes, and the phenotypic data were used to train and test genomic selection models intended to predict yield, thousand-kernel weight, number of kernels per spike, and heading date. Phenotypic data showed marked spatial variation. Therefore, different models were tested to correct the trends observed in the field. A mixed-model using moving-means as a covariate was found to best fit the data. When we applied the genomic selection models, the accuracy of predicted traits increased with spatial adjustment. Multiple genomic selection models were tested, and a Gaussian kernel model was determined to give the highest accuracy. The best predictions between environments were obtained when data from different years were used to train the model. Our results confirm that genotyping-by-sequencing is an effective tool to obtain genome-wide information for crops with complex genomes, that these data are efficient for predicting traits, and that correction of spatial variation is a crucial ingredient to increase prediction accuracy in genomic selection models.

  17. Early prediction of eruption site using lightning location data: Estimates of accuracy during past eruptions

    NASA Astrophysics Data System (ADS)

    Nína Petersen, Guðrún; Arason, Þórður; Bjornsson, Halldór

    2013-04-01

    Eruption of subglacial volcanoes may lead to catastrophic floods and therefore early determination of the exact eruption site may be critical to civil protection evacuation plans. Poor visibility due to weather or darkness often inhibit positive identification of exact eruption location for many hours. However, because of the proximity and abundance of water in powerful subglacial volcanic eruptions, they are probably always accompanied by early lightning activity in the volcanic column. Lightning location systems, designed for weather thunderstorm monitoring, based on remote detection of electromagnetic waves from lightning, can provide valuable real-time information on location of eruption site. Important aspect of such remote detection is its independence of weather, apart from thunderstorms close to the volcano. Individual lightning strikes can be 5-10 km in length and are sometimes tilted and to the side of the volcanic column. This adds to the lightning location uncertainty, which is often a few km. Furthermore, the volcanic column may be swayed by the local wind to one side. Therefore, location of a single lightning can be misleading but by calculating average location of many lightning strikes and applying wind correction a more accurate eruption site location can be obtained. In an effort to assess the expected accuracy, the average lightning locations during the past five volcanic eruptions in Iceland (1998-2011) were compared to the exact site of the eruption vent. Simultaneous weather thunderstorms might have complicated this analysis, but there were no signs of ordinary thunderstorms in Iceland during these eruptions. To identify a suitable wind correction, the vector wind at the 500 hPa pressure level (5-6 km altitude) was compared to mean lightning locations during the eruptions. The essential elements of a system, which predicts the eruption site during the first hour(s) of an eruption, will be described.

  18. Accuracy of Implant Position Transfer and Surface Detail Reproduction with Different Impression Materials and Techniques

    PubMed Central

    Alikhasi, Marzieh; Siadat, Hakimeh; Kharazifard, Mohammad Javad

    2015-01-01

    Objectives: The purpose of this study was to compare the accuracy of implant position transfer and surface detail reproduction using two impression techniques and materials. Materials and Methods: A metal model with two implants and three grooves of 0.25, 0.50 and 0.75 mm in depth on the flat superior surface of a die was fabricated. Ten regular-body polyether (PE) and 10 regular-body polyvinyl siloxane (PVS) impressions with square and conical transfer copings using open tray and closed tray techniques were made for each group. Impressions were poured with type IV stone, and linear and angular displacements of the replica heads were evaluated using a coordinate measuring machine (CMM). Also, accurate reproduction of the grooves was evaluated by a video measuring machine (VMM). These measurements were compared with the measurements calculated on the reference model that served as control, and the data were analyzed with two-way ANOVA and t-test at P= 0.05. Results: There was less linear displacement for PVS and less angular displacement for PE in closed-tray technique, and less linear displacement for PE in open tray technique (P<0.001). Also, the open tray technique showed less angular displacement with the use of PVS impression material. Detail reproduction accuracy was the same in all the groups (P>0.05). Conclusion: The open tray technique was more accurate using PE, and also both closed tray and open tray techniques had acceptable results with the use of PVS. The choice of impression material and technique made no significant difference in surface detail reproduction. PMID:27252761

  19. Accuracy of a low-cost global positioning system receiver for estimating grade during outdoor walking.

    PubMed

    de Müllenheim, Pierre-Yves; Chaudru, Ségolène; Gernigon, Marie; Mahé, Guillaume; Bickert, Sandrine; Prioux, Jacques; Noury-Desvaux, Bénédicte; Le Faucheur, Alexis

    2016-09-21

    The aim of this study was to assess, for the first time, the accuracy of a low-cost global positioning system (GPS) receiver for estimating grade during outdoor walking. Thirty subjects completed outdoor walks (2.0, 3.5 and 5.0 km · h(-1)) in three randomized conditions: 1/level walking on a 0.0% grade; 2/graded (uphill and downhill) walking on a 3.4% grade; and 3/on a 10.4% grade. Subjects were equipped with a GPS receiver (DG100, GlobalSat Technology Corp., Taiwan; ~US$75). The GPS receiver was set to record at 1 Hz and its antenna was placed on the right shoulder. Grade was calculated from GPS speed and altitude data (grade  =  altitude variation/travelled distance  ×  100). Two methods were used for the grade calculation: one using uncorrected altitude data given by the GPS receiver and another one using corrected altitude data obtained using map projection software (CartoExploreur, version 3.11.0, build 2.6.6.22, Bayo Ltd, Appoigny, France, ~US$35). Linear regression of GPS-estimated versus actual grade with R (2) coefficients, bias with 95% limits of agreement (±95% LoA), and typical error of the estimate with 95% confidence interval (TEE (95% CI)) were computed to assess the accuracy of the GPS receiver. 444 walking periods were performed. Using uncorrected altitude data, we obtained: R (2)  =  0.88 (p  <  0.001), bias  =  0.0  ±  6.6%, TEE between 1.9 (1.7-2.2)% and 4.2 (3.6-4.9)% according to the grade level. Using corrected altitude data, we obtained: R (2)  =  0.98 (p  <  0.001), bias  =  0.2  ±  1.9%, TEE between 0.2 (0.2-0.3)% and 1.0 (0.9-1.2)% according to the grade level. The low-cost GPS receiver used was weakly accurate for estimating grade during outdoor walking when using uncorrected altitude data. However, the accuracy was greatly improved when using corrected altitude data. This study supports the potential interest of using GPS for estimating energy

  20. The Diagnostic Accuracy of the Berg Balance Scale in Predicting Falls.

    PubMed

    Park, Seong-Hi; Lee, Young-Shin

    2016-10-26

    This study aimed to evaluate the predictive validity of the Berg Balance Scale (BBS) as a screening tool for fall risks among those with varied levels of balance. A total of 21 studies reporting predictive validity of the BBS of fall risk were meta-analyzed. With regard to the overall predictive validity of the BBS, the pooled sensitivity and specificity were 0.72 and 0.73, respectively; the accuracy curve area was 0.84. The findings showed statistical heterogeneity among studies. Among the sub-groups, the age group of those younger than 65 years, those with neuromuscular disease, those with 2+ falls, and those with a cutoff point of 45 to 49 showed better sensitivity with statistically less heterogeneity. The empirical evidence indicates that the BBS is a suitable tool to screen for the risk of falls and shows good predictability when used with the appropriate criteria and applied to those with neuromuscular disease.

  1. Using intron position conservation for homology-based gene prediction

    PubMed Central

    Keilwagen, Jens; Wenk, Michael; Erickson, Jessica L.; Schattat, Martin H.; Grau, Jan; Hartung, Frank

    2016-01-01

    Annotation of protein-coding genes is very important in bioinformatics and biology and has a decisive influence on many downstream analyses. Homology-based gene prediction programs allow for transferring knowledge about protein-coding genes from an annotated organism to an organism of interest. Here, we present a homology-based gene prediction program called GeMoMa. GeMoMa utilizes the conservation of intron positions within genes to predict related genes in other organisms. We assess the performance of GeMoMa and compare it with state-of-the-art competitors on plant and animal genomes using an extended best reciprocal hit approach. We find that GeMoMa often makes more precise predictions than its competitors yielding a substantially increased number of correct transcripts. Subsequently, we exemplarily validate GeMoMa predictions using Sanger sequencing. Finally, we use RNA-seq data to compare the predictions of homology-based gene prediction programs, and find again that GeMoMa performs well. Hence, we conclude that exploiting intron position conservation improves homology-based gene prediction, and we make GeMoMa freely available as command-line tool and Galaxy integration. PMID:26893356

  2. Accuracy of positioning and irradiation targeting for multiple targets in intracranial image-guided radiation therapy: a phantom study.

    PubMed

    Tominaga, Hirofumi; Araki, Fujio; Shimohigashi, Yoshinobu; Ishihara, Terunobu; Kawasaki, Keiichi; Kanetake, Nagisa; Sakata, Junichi; Iwashita, Yuki

    2014-12-21

    This study investigated the accuracy of positioning and irradiation targeting for multiple off-isocenter targets in intracranial image-guided radiation therapy (IGRT). A phantom with nine circular targets was created to evaluate both accuracies. First, the central point of the isocenter target was positioned with a combination of an ExacTrac x-ray (ETX) and a 6D couch. The positioning accuracy was determined from the deviations of coordinates of the central point in each target obtained from the kV-cone beam computed tomography (kV-CBCT) for IGRT and the planning CT. Similarly, the irradiation targeting accuracy was evaluated from the deviations of the coordinates between the central point of each target and the central point of each multi-leaf collimator (MLC) field for multiple targets. Secondly, the 6D couch was intentionally rotated together with both roll and pitch angles of 0.5° and 1° at the isocenter and similarly the deviations were evaluated. The positioning accuracy for all targets was less than 1 mm after 6D positioning corrections. The irradiation targeting accuracy was up to 1.3 mm in the anteroposterior (AP) direction for a target 87 mm away from isocenter. For the 6D couch rotations with both roll and pitch angles of 0.5° and 1°, the positioning accuracy was up to 1.0 mm and 2.3 mm in the AP direction for the target 87 mm away from the isocenter, respectively. The irradiation targeting accuracy was up to 2.1 mm and 2.6 mm in the AP direction for the target 87 mm away from the isocenter, respectively. The off-isocenter irradiation targeting accuracy became worse than the positioning accuracy. Both off-isocenter accuracies worsened in proportion to rotation angles and the distance from the isocenter to the targets. It is necessary to examine the set-up margin for off-isocenter multiple targets at each institution because irradiation targeting accuracy is peculiar to the linac machine.

  3. Accuracy of positioning and irradiation targeting for multiple targets in intracranial image-guided radiation therapy: a phantom study

    NASA Astrophysics Data System (ADS)

    Tominaga, Hirofumi; Araki, Fujio; Shimohigashi, Yoshinobu; Ishihara, Terunobu; Kawasaki, Keiichi; Kanetake, Nagisa; Sakata, Junichi; Iwashita, Yuki

    2014-12-01

    This study investigated the accuracy of positioning and irradiation targeting for multiple off-isocenter targets in intracranial image-guided radiation therapy (IGRT). A phantom with nine circular targets was created to evaluate both accuracies. First, the central point of the isocenter target was positioned with a combination of an ExacTrac x-ray (ETX) and a 6D couch. The positioning accuracy was determined from the deviations of coordinates of the central point in each target obtained from the kV-cone beam computed tomography (kV-CBCT) for IGRT and the planning CT. Similarly, the irradiation targeting accuracy was evaluated from the deviations of the coordinates between the central point of each target and the central point of each multi-leaf collimator (MLC) field for multiple targets. Secondly, the 6D couch was intentionally rotated together with both roll and pitch angles of 0.5° and 1° at the isocenter and similarly the deviations were evaluated. The positioning accuracy for all targets was less than 1 mm after 6D positioning corrections. The irradiation targeting accuracy was up to 1.3 mm in the anteroposterior (AP) direction for a target 87 mm away from isocenter. For the 6D couch rotations with both roll and pitch angles of 0.5° and 1°, the positioning accuracy was up to 1.0 mm and 2.3 mm in the AP direction for the target 87 mm away from the isocenter, respectively. The irradiation targeting accuracy was up to 2.1 mm and 2.6 mm in the AP direction for the target 87 mm away from the isocenter, respectively. The off-isocenter irradiation targeting accuracy became worse than the positioning accuracy. Both off-isocenter accuracies worsened in proportion to rotation angles and the distance from the isocenter to the targets. It is necessary to examine the set-up margin for off-isocenter multiple targets at each institution because irradiation targeting accuracy is peculiar to the linac machine.

  4. Positive Urgency Predicts Illegal Drug Use and Risky Sexual Behavior

    PubMed Central

    Zapolski, Tamika C. B.; Cyders, Melissa A.; Smith, Gregory T.

    2009-01-01

    There are several different personality traits that dispose individuals to engage in rash action. One such trait is positive urgency: the tendency to act rashly when experiencing extremely positive affect. This trait may be relevant for college student risky behavior, because it appears that a great deal of college student risky behavior is undertaken during periods of intensely positive mood states. To test this possibility, the authors conducted a longitudinal study designed to predict increases in risky sexual behavior and illegal drug use over the course of the first year of college (n = 407). In a well-fitting structural model, positive urgency predicted increases in illegal drug use and risky sexual behavior, even after controlling for time 1 (T1) involvement in both risky behaviors, biological sex, and T1 scores on four other personality dispositions to rash action. The authors discuss the theoretical and practical implications of this finding. PMID:19586152

  5. Accuracy of genomic prediction in switchgrass (Panicum virgatum L.) improved by accounting for linkage disequilibrium

    DOE PAGES

    Ramstein, Guillaume P.; Evans, Joseph; Kaeppler, Shawn M.; ...

    2016-02-11

    Switchgrass is a relatively high-yielding and environmentally sustainable biomass crop, but further genetic gains in biomass yield must be achieved to make it an economically viable bioenergy feedstock. Genomic selection (GS) is an attractive technology to generate rapid genetic gains in switchgrass, and meet the goals of a substantial displacement of petroleum use with biofuels in the near future. In this study, we empirically assessed prediction procedures for genomic selection in two different populations, consisting of 137 and 110 half-sib families of switchgrass, tested in two locations in the United States for three agronomic traits: dry matter yield, plant height,more » and heading date. Marker data were produced for the families’ parents by exome capture sequencing, generating up to 141,030 polymorphic markers with available genomic-location and annotation information. We evaluated prediction procedures that varied not only by learning schemes and prediction models, but also by the way the data were preprocessed to account for redundancy in marker information. More complex genomic prediction procedures were generally not significantly more accurate than the simplest procedure, likely due to limited population sizes. Nevertheless, a highly significant gain in prediction accuracy was achieved by transforming the marker data through a marker correlation matrix. Our results suggest that marker-data transformations and, more generally, the account of linkage disequilibrium among markers, offer valuable opportunities for improving prediction procedures in GS. Furthermore, some of the achieved prediction accuracies should motivate implementation of GS in switchgrass breeding programs.« less

  6. Assessment of Completeness and Positional Accuracy of Linear Features in Volunteered Geographic Information (vgi)

    NASA Astrophysics Data System (ADS)

    Eshghi, M.; Alesheikh, A. A.

    2015-12-01

    Recent advances in spatial data collection technologies and online services dramatically increase the contribution of ordinary people to produce, share, and use geographic information. Collecting spatial data as well as disseminating them on the internet by citizens has led to a huge source of spatial data termed as Volunteered Geographic Information (VGI) by Mike Goodchild. Although, VGI has produced previously unavailable data assets, and enriched existing ones. But its quality can be highly variable and challengeable. This presents several challenges to potential end users who are concerned about the validation and the quality assurance of the data which are collected. Almost, all the existing researches are based on how to find accurate VGI data from existing VGI data which consist of a) comparing the VGI data with the accurate official data, or b) in cases that there is no access to correct data; therefore, looking for an alternative way to determine the quality of VGI data is essential, and so forth. In this paper it has been attempt to develop a useful method to reach this goal. In this process, the positional accuracy of linear feature of Iran, Tehran OSM data have been analyzed.

  7. The accuracy of image-guided navigation for maxillary positioning in bimaxillary surgery.

    PubMed

    Sun, Yi; Luebbers, Heinz-Theo; Agbaje, Jimoh Olubanwo; Lambrichts, Ivo; Politis, Constantinus

    2014-05-01

    The aim of our study was to evaluate the accuracy of image-guided maxillary positioning in sagittal, vertical, and mediolateral direction. Between May 2011 and July 2012, 17 patients (11 males, 6 females) underwent bimaxillary surgery with the use of intraoperative surgical navigation. During Le Fort I osteotomy, the Kolibri navigation system was used to measure movement of the maxilla at the edge of the upper central upper incisor in sagittal (buccal surface), vertical (incisor edge), and mediolateral (dental midline) direction. Six weeks after surgery, a postoperative CBCT scan was taken and registered to the preoperative cone-beam computed tomography scan to identify the actual surgical movement of the maxilla. Student 2-tailed paired t test was used to evaluate differences between the measured result from navigation system and actual surgical movement of the maxilla, which were 0.44 ± 0.35 mm (P = 0.82) in the sagittal, 0.50 ± 0.35 mm (P = 0.85) in the vertical, and 0.56 ± 0.36 mm (P = 0.81) in the mediolateral direction. Our finding demonstrates that intraoperative computer navigation is a promising tool for measuring the surgical change of the maxilla in bimaxillary surgery.

  8. Reducing patient posture variability using the predicted couch position.

    PubMed

    de Kruijf, Wilhelmus J M; Martens, Rob J W

    2015-01-01

    A method is presented in which the couch position is predicted before the treatment instead of obtaining a reference position at the first treatment fraction. This prevents systematic differences in patient posture between preparation and treatment. In literature, only limited data are available on couch positioning. We position our patients at the planned couch position, allowing a small difference between skin marks and lasers, followed by online imaging. For a 3-month period, our standard deviations (mm) in couch position in the vertical, longitudinal, and lateral directions were head and neck-1.6, 2.8, and 2.5; thorax-2.9, 5.5, and 4.5; breast-3.0, 4.1, and 4.0; and pelvis-3.5, 4.0, and 4.7, respectively. We have improved the reproducibility of patient posture in our institute by using the predicted couch position. Our data may serve as a reference for other institutes because the couch position variation is less than that published in literature.

  9. Features Predicting Sentinel Lymph Node Positivity in Merkel Cell Carcinoma

    PubMed Central

    Schwartz, Jennifer L.; Griffith, Kent A.; Lowe, Lori; Wong, Sandra L.; McLean, Scott A.; Fullen, Douglas R.; Lao, Christopher D.; Hayman, James A.; Bradford, Carol R.; Rees, Riley S.; Johnson, Timothy M.; Bichakjian, Christopher K.

    2011-01-01

    Purpose Merkel cell carcinoma (MCC) is a relatively rare, potentially aggressive cutaneous malignancy. We examined the clinical and histologic features of primary MCC that may correlate with the probability of a positive sentinel lymph node (SLN). Methods Ninety-five patients with MCC who underwent SLN biopsy at the University of Michigan were identified. SLN biopsy was performed on 97 primary tumors, and an SLN was identified in 93 instances. These were reviewed for clinical and histologic features and associated SLN positivity. Univariate associations between these characteristics and a positive SLN were tested for by using either the χ2 or the Fisher's exact test. A backward elimination algorithm was used to help create a best multiple variable model to explain a positive SLN. Results SLN positivity was significantly associated with the clinical size of the lesion, greatest horizontal histologic dimension, tumor thickness, mitotic rate, and histologic growth pattern. Two competing multivariate models were generated to predict a positive SLN. The histologic growth pattern was present in both models and combined with either tumor thickness or mitotic rate. Conclusion Increasing clinical size, increasing tumor thickness, increasing mitotic rate, and infiltrative tumor growth pattern were significantly associated with a greater likelihood of a positive SLN. By using the growth pattern and tumor thickness model, no subgroup of patients was predicted to have a lower than 15% to 20% likelihood of a positive SLN. This suggests that all patients presenting with MCC without clinical evidence of regional lymph node disease should be considered for SLN biopsy. PMID:21300936

  10. Reducing patient posture variability using the predicted couch position

    SciTech Connect

    Kruijf, Wilhelmus J.M. de Martens, Rob J.W.

    2015-10-01

    A method is presented in which the couch position is predicted before the treatment instead of obtaining a reference position at the first treatment fraction. This prevents systematic differences in patient posture between preparation and treatment. In literature, only limited data are available on couch positioning. We position our patients at the planned couch position, allowing a small difference between skin marks and lasers, followed by online imaging. For a 3-month period, our standard deviations (mm) in couch position in the vertical, longitudinal, and lateral directions were head and neck—1.6, 2.8, and 2.5; thorax—2.9, 5.5, and 4.5; breast—3.0, 4.1, and 4.0; and pelvis—3.5, 4.0, and 4.7, respectively. We have improved the reproducibility of patient posture in our institute by using the predicted couch position. Our data may serve as a reference for other institutes because the couch position variation is less than that published in literature.

  11. Temporal trends in symptom experience predict the accuracy of recall PROs

    PubMed Central

    Schneider, Stefan; Broderick, Joan E.; Junghaenel, Doerte U.; Schwartz, Joseph E.; Stone, Arthur A.

    2013-01-01

    Objective Patient-reported outcome measures with reporting periods of a week or more are often used to evaluate the change of symptoms over time, but the accuracy of recall in the context of change is not well understood. This study examined whether temporal trends in symptoms that occur during the reporting period impact the accuracy of 7-day recall reports. Methods Women with premenstrual symptoms (n = 95) completed daily reports of anger, depression, fatigue, and pain intensity for 4 weeks, as well as 7-day recall reports at the end of each week. Latent class growth analysis was used to categorize recall periods based on the direction and rate of change in the daily reports. Agreement (level differences and correlations) between 7-day recall and aggregated daily scores was compared for recall periods with different temporal trends. Results Recall periods with positive, negative, and flat temporal trends were identified and they varied in accordance with weeks of the menstrual cycle. Replicating previous research, 7-day recall scores were consistently higher than aggregated daily scores, but this level difference was more pronounced for recall periods involving positive and negative trends compared with flat trends. Moreover, correlations between 7-day recall and aggregated daily scores were lower in the presence of positive and negative trends compared with flat trends. These findings were largely consistent for anger, depression, fatigue, and pain intensity. Conclusion Temporal trends in symptoms can influence the accuracy of recall reports and this should be considered in research designs involving change. PMID:23915773

  12. The accuracy of clinicians' predictions of survival in advanced cancer: a review.

    PubMed

    Cheon, Stephanie; Agarwal, Arnav; Popovic, Marko; Milakovic, Milica; Lam, Michael; Fu, Wayne; DiGiovanni, Julia; Lam, Henry; Lechner, Breanne; Pulenzas, Natalie; Chow, Ronald; Chow, Edward

    2016-01-01

    The process of formulating an accurate survival prediction is often difficult but important, as it influences the decisions of clinicians, patients, and their families. The current article aims to review the accuracy of clinicians' predictions of survival (CPS) in advanced cancer patients. A literature search of Cochrane CENTRAL, EMBASE, and MEDLINE was conducted to identify studies that reported clinicians' prediction of survival in advanced cancer patients. Studies were included if the subjects consisted of advanced cancer patients and the data reported on the ability of clinicians to predict survival, with both estimated and observed survival data present. Studies reporting on the ability of biological and molecular markers to predict survival were excluded. Fifteen studies that met the inclusion and exclusion criteria were identified. Clinicians in five studies underestimated patients' survival (estimated to observed survival ratio between 0.5 and 0.92). In contrast, 12 studies reported clinicians' overestimation of survival (ratio between 1.06 and 6). CPS in advanced cancer patients is often inaccurate and overestimated. Given these findings, clinicians should be aware of their tendency to be overoptimistic. Further investigation of predictive patient and clinician characteristics is warranted to improve clinicians' ability to predict survival.

  13. Evaluation of two methods of predicting MLC leaf positions using EPID measurements

    SciTech Connect

    Parent, Laure; Seco, Joao; Evans, Phil M.; Dance, David R.; Fielding, Andrew

    2006-09-15

    In intensity modulated radiation treatments (IMRT), the position of the field edges and the modulation within the beam are often achieved with a multileaf collimator (MLC). During the MLC calibration process, due to the finite accuracy of leaf position measurements, a systematic error may be introduced to leaf positions. Thereafter leaf positions of the MLC depend on the systematic error introduced on each leaf during MLC calibration and on the accuracy of the leaf position control system (random errors). This study presents and evaluates two methods to predict the systematic errors on the leaf positions introduced during the MLC calibration. The two presented methods are based on a series of electronic portal imaging device (EPID) measurements. A comparison with film measurements showed that the EPID could be used to measure leaf positions without introducing any bias. The first method, referred to as the 'central leaf method', is based on the method currently used at this center for MLC leaf calibration. It mimics the manner in which leaf calibration parameters are specified in the MLC control system and consequently is also used by other centers. The second method, a new method proposed by the authors and referred to as the ''individual leaf method,'' involves the measurement of two positions for each leaf (-5 and +15 cm) and the interpolation and extrapolation from these two points to any other given position. The central leaf method and the individual leaf method predicted leaf positions at prescribed positions of -11, 0, 5, and 10 cm within 2.3 and 1.0 mm, respectively, with a standard deviation (SD) of 0.3 and 0.2 mm, respectively. The individual leaf method provided a better prediction of the leaf positions than the central leaf method. Reproducibility tests for leaf positions of -5 and +15 cm were performed. The reproducibility was within 0.4 mm on the same day and 0.4 mm six weeks later (1 SD). Measurements at gantry angles of 0 deg., 90 deg., and 270 deg

  14. Empathic accuracy for happiness in the daily lives of older couples: Fluid cognitive performance predicts pattern accuracy among men.

    PubMed

    Hülür, Gizem; Hoppmann, Christiane A; Rauers, Antje; Schade, Hannah; Ram, Nilam; Gerstorf, Denis

    2016-08-01

    Correctly identifying other's emotional states is a central cognitive component of empathy. We examined the role of fluid cognitive performance for empathic accuracy for happiness in the daily lives of 86 older couples (mean relationship length = 45 years; mean age = 75 years) on up to 42 occasions over 7 consecutive days. Men performing better on the Digit Symbol test were more accurate in identifying ups and downs of their partner's happiness. A similar association was not found for women. We discuss the potential role of fluid cognitive performance and other individual, partner, and situation characteristics for empathic accuracy. (PsycINFO Database Record

  15. Classifier-based latency estimation: a novel way to estimate and predict BCI accuracy

    NASA Astrophysics Data System (ADS)

    Thompson, David E.; Warschausky, Seth; Huggins, Jane E.

    2013-02-01

    Objective. Brain-computer interfaces (BCIs) that detect event-related potentials (ERPs) rely on classification schemes that are vulnerable to latency jitter, a phenomenon known to occur with ERPs such as the P300 response. The objective of this work was to investigate the role that latency jitter plays in BCI classification. Approach. We developed a novel method, classifier-based latency estimation (CBLE), based on a generalization of Woody filtering. The technique works by presenting the time-shifted data to the classifier, and using the time shift that corresponds to the maximal classifier score. Main results. The variance of CBLE estimates correlates significantly (p < 10-42) with BCI accuracy in the Farwell-Donchin BCI paradigm. Additionally, CBLE predicts same-day accuracy, even from small datasets or datasets that have already been used for classifier training, better than the accuracy on the small dataset (p < 0.05). The technique should be relatively classifier-independent, and the results were confirmed on two linear classifiers. Significance. The results suggest that latency jitter may be an important cause of poor BCI performance, and methods that correct for latency jitter may improve that performance. CBLE can also be used to decrease the amount of data needed for accuracy estimation, allowing research on effects with shorter timescales.

  16. Predicting hydration free energies with chemical accuracy: the SAMPL4 challenge.

    PubMed

    Sandberg, Lars

    2014-03-01

    An implicit solvent model described by a non-simple dielectric medium is used for the prediction of hydration free energies on the dataset of 47 molecules in the SAMPL4 challenge. The solute is represented by a minimal parameter set model based on a new all atom force-field, named the liquid simulation force-field. The importance of a first solvation shell correction to the hydration free energy prediction is discussed and two different approaches are introduced to address it: either with an empirical correction to a few functional groups (alcohol, ether, ester, amines and aromatic nitrogen), or an ab initio correction based on the formation of a solute/explicit water complex. Both approaches give equally good predictions with an average unsigned error <1 kcal/mol. Chemical accuracy is obtained.

  17. Accuracy of genomic prediction of purebreds for cross bred performance in pigs.

    PubMed

    Hidalgo, A M; Bastiaansen, J W M; Lopes, M S; Calus, M P L; de Koning, D J

    2016-12-01

    In pig breeding, as the final product is a cross bred (CB) animal, the goal is to increase the CB performance. This goal requires different strategies for the implementation of genomic selection from what is currently implemented in, for example dairy cattle breeding. A good strategy is to estimate marker effects on the basis of CB performance and subsequently use them to select pure bred (PB) breeding animals. The objective of our study was to assess empirically the predictive ability (accuracy) of direct genomic values of PB for CB performance across two traits using CB and PB genomic and phenotypic data. We studied three scenarios in which genetic merit was predicted within each population, and four scenarios where PB genetic merit for CB performance was predicted based on either CB or a PB training data. Accuracy of prediction of PB genetic merit for CB performance based on CB training data ranged from 0.23 to 0.27 for gestation length (GLE), whereas it ranged from 0.11 to 0.22 for total number of piglets born (TNB). When based on PB training data, it ranged from 0.35 to 0.55 for GLE and from 0.30 to 0.40 for TNB. Our results showed that it is possible to predict PB genetic merit for CB performance using CB training data, but predictive ability was lower than training using PB training data. This result is mainly due to the structure of our data, which had small-to-moderate size of the CB training data set, low relationship between the CB training and the PB validation populations, and a high genetic correlation (0.94 for GLE and 0.90 for TNB) between the studied traits in PB and CB individuals, thus favouring selection on the basis of PB data.

  18. Accuracy of time comparison derived from reception of LORAN-C and Global Positioning System time signals

    NASA Astrophysics Data System (ADS)

    Horiai, Koji

    1992-10-01

    The accuracy of time comparison by means of the reception of common time signals, namely, LORAN-C and Global Positioning System (GPS), is examined. Differences of UTC from the emission times of these two radio wave signals measured at four Japanese stations and one U.S. station are analyzed and compared with the clock comparison reports published by the Bureau International des Poids et Mesures. The accuracy of the time comparison via LORAN-C signals of the northwest Pacific chain is about 3.61 microns and that via GPS is 0.14 microns. The accuracy analysis reveals the existence of systematic errors at the individual stations. In LORAN-C, the most serious error comes from those in the delay time calibration of receiving instruments and estimation of the propagation delay over land. Calibration of the clocks by a portable clock improves the accuracy of the GPS method to the accuracy of the GPS signals.

  19. A real-time predictive simulation of abdominal viscera positions during quiet free breathing.

    PubMed

    Hostettler, A; Nicolau, S A; Rémond, Y; Marescaux, J; Soler, L

    2010-12-01

    Prediction of abdominal viscera and tumour positions during free breathing is a major challenge from which several medical applications could benefit. For instance, in radiotherapy it would reduce the healthy tissue irradiation. In this paper, we present a new approach to predict real-time abdominal viscera positions during free breathing. Our method needs an abdo-thoracic 3D preoperative CT or MR image, a second one limited to the diaphragmatic area, and a tracking of the patient's skin position. First, a physical analysis of the breathing motion shows it is possible to predict accurately abdominal viscera positions from the skin position and a modelling of the diaphragm motion. Secondly, a quantitative analysis of the skin and organ motion allows us to define the demands our real-time simulation has to fulfill. Then, we present in detail all the necessary steps of our original method to compute a deformation field from data extracted in both 3D preoperative image and skin surface tracking. Finally, experiments carried out with two human data show that our simulation model predicts abdominal viscera positions, such as liver, kidneys or spleen, at 50 Hz with an accuracy within 2-3 mm.

  20. Predicting gram-positive bacterial protein subcellular localization based on localization motifs.

    PubMed

    Hu, Yinxia; Li, Tonghua; Sun, Jiangming; Tang, Shengnan; Xiong, Wenwei; Li, Dapeng; Chen, Guanyan; Cong, Peisheng

    2012-09-07

    The subcellular localization of proteins is closely related to their functions. In this work, we propose a novel approach based on localization motifs to improve the accuracy of predicting subcellular localization of Gram-positive bacterial proteins. Our approach performed well on a five-fold cross validation with an overall success rate of 89.5%. Besides, the overall success rate of an independent testing dataset was 97.7%. Moreover, our approach was tested using a new experimentally-determined set of Gram-positive bacteria proteins and achieved an overall success rate of 96.3%.

  1. Accuracy of some simple models for predicting particulate interception and retention in agricultural systems

    SciTech Connect

    Pinder, J.E. III; McLeod, K.W.; Adriano, D.C.

    1989-04-01

    The accuracy of three radionuclide transfer models for predicting the interception and retention of airborne particles by agricultural crops was tested using Pu-bearing aerosols released to the atmosphere from nuclear fuel facilities on the U.S. Department of Energy's Savannah River Plant, near Aiken, SC. The models evaluated were: (1) NRC, the model defined in U.S. Nuclear Regulatory Guide 1.109; (2) FOOD, a model similar to the NRC model that also predicts concentrations in grains; and (3) AGNS, a model developed from the NRC model for the southeastern United States. Plutonium concentrations in vegetation and grain were predicted from measured deposition rates and compared to concentrations observed in the field. Crops included wheat, soybeans, corn and cabbage. Although predictions of the three models differed by less than a factor of 4, they showed different abilities to predict concentrations observed in the field. The NRC and FOOD models consistently underpredicted the observed Pu concentrations for vegetation. The AGNS model was a more accurate predictor of Pu concentrations for vegetation. Both the FOOD and AGNS models accurately predicted the Pu concentrations for grains.

  2. Evaluation of accuracy of linear regression models in predicting urban stormwater discharge characteristics.

    PubMed

    Madarang, Krish J; Kang, Joo-Hyon

    2014-06-01

    Stormwater runoff has been identified as a source of pollution for the environment, especially for receiving waters. In order to quantify and manage the impacts of stormwater runoff on the environment, predictive models and mathematical models have been developed. Predictive tools such as regression models have been widely used to predict stormwater discharge characteristics. Storm event characteristics, such as antecedent dry days (ADD), have been related to response variables, such as pollutant loads and concentrations. However it has been a controversial issue among many studies to consider ADD as an important variable in predicting stormwater discharge characteristics. In this study, we examined the accuracy of general linear regression models in predicting discharge characteristics of roadway runoff. A total of 17 storm events were monitored in two highway segments, located in Gwangju, Korea. Data from the monitoring were used to calibrate United States Environmental Protection Agency's Storm Water Management Model (SWMM). The calibrated SWMM was simulated for 55 storm events, and the results of total suspended solid (TSS) discharge loads and event mean concentrations (EMC) were extracted. From these data, linear regression models were developed. R(2) and p-values of the regression of ADD for both TSS loads and EMCs were investigated. Results showed that pollutant loads were better predicted than pollutant EMC in the multiple regression models. Regression may not provide the true effect of site-specific characteristics, due to uncertainty in the data.

  3. Consonant Production Accuracy in Young Cochlear Implant Recipients: Developmental Sound Classes and Word Position Effects

    ERIC Educational Resources Information Center

    Ertmer, David J.; Kloiber, Diana True; Jung, Jongmin; Kirleis, Katie Connell; Bradford, Denise

    2012-01-01

    Purpose: To compare young cochlear implant (CI) recipients' consonant production accuracy with that of age- and gender-matched peers who were typically developing (TD). In addition to examining initial consonants, the authors compiled new data regarding the accuracy of final consonants and the order of consonant acquisition. Methods: Eleven young…

  4. Enhancing Predictive Accuracy of Cardiac Autonomic Neuropathy Using Blood Biochemistry Features and Iterative Multitier Ensembles.

    PubMed

    Abawajy, Jemal; Kelarev, Andrei; Chowdhury, Morshed U; Jelinek, Herbert F

    2016-01-01

    Blood biochemistry attributes form an important class of tests, routinely collected several times per year for many patients with diabetes. The objective of this study is to investigate the role of blood biochemistry for improving the predictive accuracy of the diagnosis of cardiac autonomic neuropathy (CAN) progression. Blood biochemistry contributes to CAN, and so it is a causative factor that can provide additional power for the diagnosis of CAN especially in the absence of a complete set of Ewing tests. We introduce automated iterative multitier ensembles (AIME) and investigate their performance in comparison to base classifiers and standard ensemble classifiers for blood biochemistry attributes. AIME incorporate diverse ensembles into several tiers simultaneously and combine them into one automatically generated integrated system so that one ensemble acts as an integral part of another ensemble. We carried out extensive experimental analysis using large datasets from the diabetes screening research initiative (DiScRi) project. The results of our experiments show that several blood biochemistry attributes can be used to supplement the Ewing battery for the detection of CAN in situations where one or more of the Ewing tests cannot be completed because of the individual difficulties faced by each patient in performing the tests. The results show that AIME provide higher accuracy as a multitier CAN classification paradigm. The best predictive accuracy of 99.57% has been obtained by the AIME combining decorate on top tier with bagging on middle tier based on random forest. Practitioners can use these findings to increase the accuracy of CAN diagnosis.

  5. Using skin impedance to improve prediction accuracy of continuous glucose monitoring system

    NASA Astrophysics Data System (ADS)

    Yu, Haixia; Liu, Jin; Shi, Ting; Li, Dachao; Du, Zhenhui; Xu, Kexin

    2008-02-01

    The continuous blood glucose monitoring system using interstitial fluid (ISF) extracted by ultrasound and vacuum is proposed in this paper. The skin impedance measurement is introduced into the system to monitor the skin permeability variation. Low-frequency ultrasound is applied on skin surface to enhance the skin permeability by disrupting the lipid bilayers of the stratum corneum (SC), and then ISF is extracted out of skin continuously by vacuum. The extracted ISF is diluted and the concentration of glucose in it is detected by a biosensor and used to predict the blood glucose concentration. The skin permeability is variable during the extraction, and its variation affects the prediction accuracy. The skin impedance is an excellent indicator of skin permeability in that the lipid bilayers of the SC, which offer electrical resistance to the skin, retard transdermal transport of molecules. So the skin impedance measured during the extraction is transformed to skin conductivity to estimate correlation coefficient between skin conductivity and permeability. Skin conductivity correlates well with skin permeability. The method and experiment system mentioned above may be significative for improving the prediction accuracy of continuous blood glucose monitoring system.

  6. Knowing right from wrong in mental arithmetic judgments: calibration of confidence predicts the development of accuracy.

    PubMed

    Rinne, Luke F; Mazzocco, Michèle M M

    2014-01-01

    Does knowing when mental arithmetic judgments are right--and when they are wrong--lead to more accurate judgments over time? We hypothesize that the successful detection of errors (and avoidance of false alarms) may contribute to the development of mental arithmetic performance. Insight into error detection abilities can be gained by examining the "calibration" of mental arithmetic judgments-that is, the alignment between confidence in judgments and the accuracy of those judgments. Calibration may be viewed as a measure of metacognitive monitoring ability. We conducted a developmental longitudinal investigation of the relationship between the calibration of children's mental arithmetic judgments and their performance on a mental arithmetic task. Annually between Grades 5 and 8, children completed a problem verification task in which they rapidly judged the accuracy of arithmetic expressions (e.g., 25 + 50 = 75) and rated their confidence in each judgment. Results showed that calibration was strongly related to concurrent mental arithmetic performance, that calibration continued to develop even as mental arithmetic accuracy approached ceiling, that poor calibration distinguished children with mathematics learning disability from both low and typically achieving children, and that better calibration in Grade 5 predicted larger gains in mental arithmetic accuracy between Grades 5 and 8. We propose that good calibration supports the implementation of cognitive control, leading to long-term improvement in mental arithmetic accuracy. Because mental arithmetic "fluency" is critical for higher-level mathematics competence, calibration of confidence in mental arithmetic judgments may represent a novel and important developmental predictor of future mathematics performance.

  7. Knowing Right From Wrong In Mental Arithmetic Judgments: Calibration Of Confidence Predicts The Development Of Accuracy

    PubMed Central

    Rinne, Luke F.; Mazzocco, Michèle M. M.

    2014-01-01

    Does knowing when mental arithmetic judgments are right—and when they are wrong—lead to more accurate judgments over time? We hypothesize that the successful detection of errors (and avoidance of false alarms) may contribute to the development of mental arithmetic performance. Insight into error detection abilities can be gained by examining the “calibration” of mental arithmetic judgments—that is, the alignment between confidence in judgments and the accuracy of those judgments. Calibration may be viewed as a measure of metacognitive monitoring ability. We conducted a developmental longitudinal investigation of the relationship between the calibration of children's mental arithmetic judgments and their performance on a mental arithmetic task. Annually between Grades 5 and 8, children completed a problem verification task in which they rapidly judged the accuracy of arithmetic expressions (e.g., 25+50 = 75) and rated their confidence in each judgment. Results showed that calibration was strongly related to concurrent mental arithmetic performance, that calibration continued to develop even as mental arithmetic accuracy approached ceiling, that poor calibration distinguished children with mathematics learning disability from both low and typically achieving children, and that better calibration in Grade 5 predicted larger gains in mental arithmetic accuracy between Grades 5 and 8. We propose that good calibration supports the implementation of cognitive control, leading to long-term improvement in mental arithmetic accuracy. Because mental arithmetic “fluency” is critical for higher-level mathematics competence, calibration of confidence in mental arithmetic judgments may represent a novel and important developmental predictor of future mathematics performance. PMID:24988539

  8. Accuracy and Predictability of PANC-3 Scoring System over APACHE II in Acute Pancreatitis: A Prospective Study

    PubMed Central

    Vishnu, Vikram Hubbanageri; Muniyappa, Shridhar; Prasath, Arun

    2017-01-01

    Introduction Acute Pancreatitis (AP) is one of the common conditions encountered in the emergency room. The course of the disease ranges from mild form to severe acute form. Most of these episodes are mild and spontaneously subsiding within 3 to 5 days. In contrast, Severe Acute Pancreatitis (SAP) occurring in around 15-20% of all cases, mortality can range between 10 to 85% across various centres and countries. In such a situation we need an indicator which can predict the outcome of an attack, as severe or mild, as early as possible and such an indicator should be sensitive and specific enough to trust upon. PANC-3 scoring is such a scoring system in predicting the outcome of an attack of AP. Aim To assess the accuracy and predictability of PANC-3 scoring system over APACHE II in predicting severity in an attack of AP. Materials and Methods This prospective study was conducted on 82 patients admitted with the diagnosis of pancreatitis. Investigations to evaluate PANC-3 and APACHE II were done on all the patients and the PANC-3 and APACHE II score was calculated. Results PANC-3 score has a sensitivity of 82.6% and specificity of 77.9%, the test had a Positive Predictive Value (PPV) of 0.59 and Negative Predictive Value (NPV) of 0.92. Sensitivity of APACHE II in predicting SAP was 91.3% and specificity was 96.6% with PPV of 0.91, NPV was 0.96. Conclusion Our study shows that PANC-3 can be used to predict the severity of pancreatitis as efficiently as APACHE II. The interpretation of PANC-3 does not need expertise and can be applied at the time of admission which is an advantage when compared to classical scoring systems.

  9. Voxel inversion of airborne electromagnetic data for improved groundwater model construction and prediction accuracy

    NASA Astrophysics Data System (ADS)

    Kruse Christensen, Nikolaj; Ferre, Ty Paul A.; Fiandaca, Gianluca; Christensen, Steen

    2017-03-01

    smoothness constraint. This is true for predictions of recharge area, head change, and stream discharge, while we find no improvement for prediction of groundwater age. Furthermore, we show that the model prediction accuracy improves with AEM data quality for predictions of recharge area, head change, and stream discharge, while there appears to be no accuracy improvement for the prediction of groundwater age.

  10. Intensive Care Unit Admission Parameters Improve the Accuracy of Operative Mortality Predictive Models in Cardiac Surgery

    PubMed Central

    Ranucci, Marco; Ballotta, Andrea; Castelvecchio, Serenella; Baryshnikova, Ekaterina; Brozzi, Simonetta; Boncilli, Alessandra

    2010-01-01

    Background Operative mortality risk in cardiac surgery is usually assessed using preoperative risk models. However, intraoperative factors may change the risk profile of the patients, and parameters at the admission in the intensive care unit may be relevant in determining the operative mortality. This study investigates the association between a number of parameters at the admission in the intensive care unit and the operative mortality, and verifies the hypothesis that including these parameters into the preoperative risk models may increase the accuracy of prediction of the operative mortality. Methodology 929 adult patients who underwent cardiac surgery were admitted to the study. The preoperative risk profile was assessed using the logistic EuroSCORE and the ACEF score. A number of parameters recorded at the admission in the intensive care unit were explored for univariate and multivariable association with the operative mortality. Principal Findings A heart rate higher than 120 beats per minute and a blood lactate value higher than 4 mmol/L at the admission in the intensive care unit were independent predictors of operative mortality, with odds ratio of 6.7 and 13.4 respectively. Including these parameters into the logistic EuroSCORE and the ACEF score increased their accuracy (area under the curve 0.85 to 0.88 for the logistic EuroSCORE and 0.81 to 0.86 for the ACEF score). Conclusions A double-stage assessment of operative mortality risk provides a higher accuracy of the prediction. Elevated blood lactates and tachycardia reflect a condition of inadequate cardiac output. Their inclusion in the assessment of the severity of the clinical conditions after cardiac surgery may offer a useful tool to introduce more sophisticated hemodynamic monitoring techniques. Comparison between the predicted operative mortality risk before and after the operation may offer an assessment of the operative performance. PMID:21042411

  11. Accuracy of the Timed Up and Go test for predicting sarcopenia in elderly hospitalized patients

    PubMed Central

    Martinez, Bruno Prata; Gomes, Isabela Barboza; de Oliveira, Carolina Santana; Ramos, Isis Resende; Rocha, Mônica Diniz Marques; Júnior, Luiz Alberto Forgiarini; Camelier, Fernanda Warken Rosa; Camelier, Aquiles Assunção

    2015-01-01

    OBJECTIVES: The ability of the Timed Up and Go test to predict sarcopenia has not been evaluated previously. The objective of this study was to evaluate the accuracy of the Timed Up and Go test for predicting sarcopenia in elderly hospitalized patients. METHODS: This cross-sectional study analyzed 68 elderly patients (≥60 years of age) in a private hospital in the city of Salvador-BA, Brazil, between the 1st and 5th day of hospitalization. The predictive variable was the Timed Up and Go test score, and the outcome of interest was the presence of sarcopenia (reduced muscle mass associated with a reduction in handgrip strength and/or weak physical performance in a 6-m gait-speed test). After the descriptive data analyses, the sensitivity, specificity and accuracy of a test using the predictive variable to predict the presence of sarcopenia were calculated. RESULTS: In total, 68 elderly individuals, with a mean age 70.4±7.7 years, were evaluated. The subjects had a Charlson Comorbidity Index score of 5.35±1.97. Most (64.7%) of the subjects had a clinical admission profile; the main reasons for hospitalization were cardiovascular disorders (22.1%), pneumonia (19.1%) and abdominal disorders (10.2%). The frequency of sarcopenia in the sample was 22.1%, and the mean length of time spent performing the Timed Up and Go test was 10.02±5.38 s. A time longer than or equal to a cutoff of 10.85 s on the Timed Up and Go test predicted sarcopenia with a sensitivity of 67% and a specificity of 88.7%. The accuracy of this cutoff for the Timed Up and Go test was good (0.80; IC=0.66-0.94; p=0.002). CONCLUSION: The Timed Up and Go test was shown to be a predictor of sarcopenia in elderly hospitalized patients. PMID:26039955

  12. Accuracy of predictive equations for resting metabolic rate in Korean athletic and non-athletic adolescents

    PubMed Central

    Kim, Jae-Hee; Kim, Myung-Hee; Kim, Gwi-Sun; Park, Ji-Sun

    2015-01-01

    BACKGROUND/OBJECTIVES Athletes generally desire changes in body composition in order to enhance their athletic performance. Often, athletes will practice chronic energy restrictions to attain body composition changes, altering their energy needs. Prediction of resting metabolic rates (RMR) is important in helping to determine an athlete's energy expenditure. This study compared measured RMR of athletic and non-athletic adolescents with predicted RMR from commonly used prediction equations to identify the most accurate equation applicable for adolescent athletes. SUBJECTS/METHODS A total of 50 athletes (mean age of 16.6 ± 1.0 years, 30 males and 20 females) and 50 non-athletes (mean age of 16.5 ± 0.5 years, 30 males and 20 females) were enrolled in the study. The RMR of subjects was measured using indirect calorimetry. The accuracy of 11 RMR prediction equations was evaluated for bias, Pearson's correlation coefficient, and Bland-Altman analysis. RESULTS Until more accurate prediction equations are developed, our findings recommend using the formulas by Cunningham (-29.8 kcal/day, limits of agreement -318.7 and +259.1 kcal/day) and Park (-0.842 kcal/day, limits of agreement -198.9 and +196.9 kcal/day) for prediction of RMR when studying male adolescent athletes. Among the new prediction formulas reviewed, the formula included in the fat-free mass as a variable [RMR = 730.4 + 15 × fat-free mass] is paramount when examining athletes. CONCLUSIONS The RMR prediction equation developed in this study is better in assessing the resting metabolic rate of Korean athletic adolescents. PMID:26244075

  13. Predictive position computations mediated by parietal areas: TMS evidence.

    PubMed

    Edwards, Grace; Paeye, Céline; Marque, Philippe; VanRullen, Rufin; Cavanagh, Patrick

    2017-03-22

    When objects move or the eyes move, the visual system can predict the consequence and generate a percept of the target at its new position. This predictive localization may depend on eye movement control in the frontal eye fields (FEF) and the intraparietal sulcus (IPS) and on motion analysis in the medial temporal area (MT). Across two experiments we examined whether repetitive transcranial magnetic stimulation (rTMS) over right FEF, right IPS, right MT, and a control site, peripheral V1/V2, diminished participants' perception of two cases of predictive position perception: trans-saccadic fusion, and the flash grab illusion, both presented in the contralateral visual field. In trans-saccadic fusion trials, participants saccade toward a stimulus that is replaced with another stimulus during the saccade. Frequently, predictive position mechanisms lead to a fused percept of pre- and post-saccade stimuli (Paeye et al., 2017). We found that rTMS to IPS significantly decreased the frequency of perceiving trans-saccadic fusion within the first 10min after stimulation. In the flash grab illusion, a target is flashed on a moving background leading to the percept that the target has shifted in the direction of the motion after the flash (Cavanagh and Anstis, 2013). In the first experiment, the reduction in the flash grab illusion after rTMS to IPS and FEF did not reach significance. In the second experiment, using a stronger version of the flash grab, the illusory shift did decrease significantly after rTMS to IPS although not after rTMS to FEF or to MT. These findings suggest that right IPS contributes to predictive position perception during saccades and motion processing in the contralateral visual field.

  14. The accuracy of body mass prediction for elderly specimens: Implications for paleoanthropology and legal medicine.

    PubMed

    Chevalier, Tony; Lefèvre, Philippe; Clarys, Jan Pieter; Beauthier, Jean-Pol

    2016-10-01

    Different practices in paleoanthropology and legal medicine raise questions concerning the robustness of body mass (BM) prediction. Integrating personal identification from body mass estimation with skeleton is not a classic approach in legal medicine. The originality of our study is the use of an elderly sample in order to push prediction methods to their limits and to discuss about implications in paleoanthropology and legal medicine. The aim is to observe the accuracy of BM prediction in relation to the body mass index (BMI, index of classification) using five femoral head (FH) methods and one shaft (FSH) method. The sample is composed of 41 dry femurs obtained from dissection where age (c. 82 years) and gender are known, and weight (c. 59.5 kg) and height are measured upon admission to the body leg service. We show that the estimation of the mean BM of the elderly sample is not significantly different to the real mean BM when the appropriate formula is used for the femoral head diameter. In fact, the best prediction is obtained with the McHenry formula (1992), which was based on a sample with an equivalent average mass to that of our sample. In comparison, external shaft diameters, which are known to be more influenced by mechanical stimuli than femoral head diameters, yield less satisfactory results with the McHenry formula (1992) for shaft diameters. Based on all the methods used and the distinctive selected sample, overestimation (always observed with the different femoral head methods) can be restricted to 1.1%. The observed overestimation with the shaft method can be restricted to 7%. However, the estimation of individual BM is much less reliable. The BMI has a strong impact on the accuracy of individual BM prediction, and is unquestionably more reliable for individuals with normal BMI (9.6% vs 16.7% for the best prediction error). In this case, the FH method is also the better predictive method but not if we integrate the total sample (i.e., the FSH

  15. Comparison of several molecular docking programs: pose prediction and virtual screening accuracy.

    PubMed

    Cross, Jason B; Thompson, David C; Rai, Brajesh K; Baber, J Christian; Fan, Kristi Yi; Hu, Yongbo; Humblet, Christine

    2009-06-01

    Molecular docking programs are widely used modeling tools for predicting ligand binding modes and structure based virtual screening. In this study, six molecular docking programs (DOCK, FlexX, GLIDE, ICM, PhDOCK, and Surflex) were evaluated using metrics intended to assess docking pose and virtual screening accuracy. Cognate ligand docking to 68 diverse, high-resolution X-ray complexes revealed that ICM, GLIDE, and Surflex generated ligand poses close to the X-ray conformation more often than the other docking programs. GLIDE and Surflex also outperformed the other docking programs when used for virtual screening, based on mean ROC AUC and ROC enrichment values obtained for the 40 protein targets in the Directory of Useful Decoys (DUD). Further analysis uncovered general trends in accuracy that are specific for particular protein families. Modifying basic parameters in the software was shown to have a significant effect on docking and virtual screening results, suggesting that expert knowledge is critical for optimizing the accuracy of these methods.

  16. Diagnostic accuracy of bedside tests for predicting difficult intubation in Indian population: An observational study

    PubMed Central

    Dhanger, Sangeeta; Gupta, Suman Lata; Vinayagam, Stalin; Bidkar, Prasanna Udupi; Elakkumanan, Lenin Babu; Badhe, Ashok Shankar

    2016-01-01

    Background: Unanticipated difficult intubation can be challenging to anesthesiologists, and various bedside tests have been tried to predict difficult intubation. Aims: The aim of this study was to determine the incidence of difficult intubation in the Indian population and also to determine the diagnostic accuracy of bedside tests in predicting difficult intubation. Settings and Design: In this study, 200 patients belonging to age group 18–60 years of American Society of Anesthesiologists I and II, scheduled for surgery under general anesthesia requiring endotracheal intubation were enrolled. Patients with upper airway pathology, neck mass, and cervical spine injury were excluded from the study. Materials and Methods: An attending anesthesiologist conducted preoperative assessment and recorded parameters such as body mass index, modified Mallampati grading, inter-incisor distance, neck circumference, and thyromental distance (NC/TMD). After standard anesthetic induction, laryngoscopy was performed, and intubation difficulty assessed using intubation difficulty scale on the basis of seven variables. Statistical Analysis: The Chi-square test or student t-test was performed when appropriate. The binary multivariate logistic regression (forward-Wald) model was used to determine the independent risk factors. Results: Among the 200 patients, 26 patients had difficult intubation with an incidence of 13%. Among different variables, the Mallampati score and NC/TMD were independently associated with difficult intubation. Receiver operating characteristic curve showed a cut-off point of 3 or 4 for Mallampati score and 5.62 for NC/TMD to predict difficult intubation. Conclusion: The diagnostic accuracy of NC/TM ratio and Mallampatti score were better compared to other bedside tests to predict difficult intubation in Indian population. PMID:26957691

  17. Prediction Accuracy in Multivariate Repeated-Measures Bayesian Forecasting Models with Examples Drawn from Research on Sleep and Circadian Rhythms.

    PubMed

    Kogan, Clark; Kalachev, Leonid; Van Dongen, Hans P A

    2016-01-01

    In study designs with repeated measures for multiple subjects, population models capturing within- and between-subjects variances enable efficient individualized prediction of outcome measures (response variables) by incorporating individuals response data through Bayesian forecasting. When measurement constraints preclude reasonable levels of prediction accuracy, additional (secondary) response variables measured alongside the primary response may help to increase prediction accuracy. We investigate this for the case of substantial between-subjects correlation between primary and secondary response variables, assuming negligible within-subjects correlation. We show how to determine the accuracy of primary response predictions as a function of secondary response observations. Given measurement costs for primary and secondary variables, we determine the number of observations that produces, with minimal cost, a fixed average prediction accuracy for a model of subject means. We illustrate this with estimation of subject-specific sleep parameters using polysomnography and wrist actigraphy. We also consider prediction accuracy in an example time-dependent, linear model and derive equations for the optimal timing of measurements to achieve, on average, the best prediction accuracy. Finally, we examine an example involving a circadian rhythm model and show numerically that secondary variables can improve individualized predictions in this time-dependent nonlinear model as well.

  18. Functional Knowledge Transfer for High-accuracy Prediction of Under-studied Biological Processes

    PubMed Central

    Rowland, Jessica; Guan, Yuanfang; Bongo, Lars A.; Burdine, Rebecca D.; Troyanskaya, Olga G.

    2013-01-01

    A key challenge in genetics is identifying the functional roles of genes in pathways. Numerous functional genomics techniques (e.g. machine learning) that predict protein function have been developed to address this question. These methods generally build from existing annotations of genes to pathways and thus are often unable to identify additional genes participating in processes that are not already well studied. Many of these processes are well studied in some organism, but not necessarily in an investigator's organism of interest. Sequence-based search methods (e.g. BLAST) have been used to transfer such annotation information between organisms. We demonstrate that functional genomics can complement traditional sequence similarity to improve the transfer of gene annotations between organisms. Our method transfers annotations only when functionally appropriate as determined by genomic data and can be used with any prediction algorithm to combine transferred gene function knowledge with organism-specific high-throughput data to enable accurate function prediction. We show that diverse state-of-art machine learning algorithms leveraging functional knowledge transfer (FKT) dramatically improve their accuracy in predicting gene-pathway membership, particularly for processes with little experimental knowledge in an organism. We also show that our method compares favorably to annotation transfer by sequence similarity. Next, we deploy FKT with state-of-the-art SVM classifier to predict novel genes to 11,000 biological processes across six diverse organisms and expand the coverage of accurate function predictions to processes that are often ignored because of a dearth of annotated genes in an organism. Finally, we perform in vivo experimental investigation in Danio rerio and confirm the regulatory role of our top predicted novel gene, wnt5b, in leftward cell migration during heart development. FKT is immediately applicable to many bioinformatics techniques and will

  19. MLC positional accuracy evaluation through the Picket Fence test on EBT2 films and a 3D volumetric phantom.

    PubMed

    Antypas, Christos; Floros, Ioannis; Rouchota, Maritina; Armpilia, Christina; Lyra, Maria

    2015-03-08

    The accuracy of MLC positions during radiotherapy is important as even small positional deviations can translate into considerable dose delivery errors. This becomes crucial when radiosensitive organs are located near the treated volume and especially during IMRT, where dose gradients are steep. A test commonly conducted to measure the positional accuracy of the MLCs is the Picket Fence test. In this study two alterations of the Picket Fence test were performed and evaluated, the first one using radiochromic EBT2 films and the second one the Delta4PT diode array phantom and its software. Our results showed that EBT2 films provide a relatively fast, qualitative visual inspection of the significant leaf dispositions. When slight inaccuracies need to be revealed or precise numerical results for each leaf position are needed, Delta4PT provides the desired accuracy of 1 mm. In treatment modalities where a higher accuracy is required in the delivered dose distribution, such as in IMRT, precise numerical values of the measurements for the MLC positional inspection are required.

  20. Non-parametric estimation of a time-dependent predictive accuracy curve.

    PubMed

    Saha-Chaudhuri, P; Heagerty, P J

    2013-01-01

    A major biomedical goal associated with evaluating a candidate biomarker or developing a predictive model score for event-time outcomes is to accurately distinguish between incident cases from the controls surviving beyond t throughout the entire study period. Extensions of standard binary classification measures like time-dependent sensitivity, specificity, and receiver operating characteristic (ROC) curves have been developed in this context (Heagerty, P. J., and others, 2000. Time-dependent ROC curves for censored survival data and a diagnostic marker. Biometrics 56, 337-344). We propose a direct, non-parametric method to estimate the time-dependent Area under the curve (AUC) which we refer to as the weighted mean rank (WMR) estimator. The proposed estimator performs well relative to the semi-parametric AUC curve estimator of Heagerty and Zheng (2005. Survival model predictive accuracy and ROC curves. Biometrics 61, 92-105). We establish the asymptotic properties of the proposed estimator and show that the accuracy of markers can be compared very simply using the difference in the WMR statistics. Estimators of pointwise standard errors are provided.

  1. Accuracy of Igenity genomically estimated breeding values for predicting Australian Angus BREEDPLAN traits.

    PubMed

    Boerner, V; Johnston, D; Wu, X-L; Bauck, S

    2015-02-01

    Genomically estimated breeding values (GEBV) for Angus beef cattle are available from at least 2 commercial suppliers (Igenity [http://www.igenity.com] and Zoetis [http://www.zoetis.com]). The utility of these GEBV for improving genetic evaluation depends on their accuracies, which can be estimated by the genetic correlation with phenotypic target traits. Genomically estimated breeding values of 1,032 Angus bulls calculated from prediction equations (PE) derived by 2 different procedures in the U.S. Angus population were supplied by Igenity. Both procedures were based on Illuminia BovineSNP50 BeadChip genotypes. In procedure sg, GEBV were calculated from PE that used subsets of only 392 SNP, where these subsets were individually selected for each trait by BayesCπ. In procedure rg GEBV were calculated from PE derived in a ridge regression approach using all available SNP. Because the total set of 1,032 bulls with GEBV contained 732 individuals used in the Igenity training population, GEBV subsets were formed characterized by a decreasing average relationship between individuals in the subsets and individuals in the training population. Accuracies of GEBV were estimated as genetic correlations between GEBV and their phenotypic target traits modeling GEBV as trait observations in a bivariate REML approach, in which phenotypic observations were those recorded in the commercial Australian Angus seed stock sector. Using results from the GEBV subset excluding all training individuals as a reference, estimated accuracies were generally in agreement with those already published, with both types of GEBV (sg and rg) yielding similar results. Accuracies for growth traits ranged from 0.29 to 0.45, for reproductive traits from 0.11 to 0.53, and for carcass traits from 0.3 to 0.75. Accuracies generally decreased with an increasing genetic distance between the training and the validation population. However, for some carcass traits characterized by a low number of phenotypic

  2. How Nonrecidivism Affects Predictive Accuracy: Evidence from a Cross-Validation of the Ontario Domestic Assault Risk Assessment (ODARA)

    ERIC Educational Resources Information Center

    Hilton, N. Zoe; Harris, Grant T.

    2009-01-01

    Prediction effect sizes such as ROC area are important for demonstrating a risk assessment's generalizability and utility. How a study defines recidivism might affect predictive accuracy. Nonrecidivism is problematic when predicting specialized violence (e.g., domestic violence). The present study cross-validates the ability of the Ontario…

  3. PreCisIon: PREdiction of CIS-regulatory elements improved by gene’s positION

    PubMed Central

    Elati, Mohamed; Nicolle, Rémy; Junier, Ivan; Fernández, David; Fekih, Rim; Font, Julio; Képès, François

    2013-01-01

    Conventional approaches to predict transcriptional regulatory interactions usually rely on the definition of a shared motif sequence on the target genes of a transcription factor (TF). These efforts have been frustrated by the limited availability and accuracy of TF binding site motifs, usually represented as position-specific scoring matrices, which may match large numbers of sites and produce an unreliable list of target genes. To improve the prediction of binding sites, we propose to additionally use the unrelated knowledge of the genome layout. Indeed, it has been shown that co-regulated genes tend to be either neighbors or periodically spaced along the whole chromosome. This study demonstrates that respective gene positioning carries significant information. This novel type of information is combined with traditional sequence information by a machine learning algorithm called PreCisIon. To optimize this combination, PreCisIon builds a strong gene target classifier by adaptively combining weak classifiers based on either local binding sequence or global gene position. This strategy generically paves the way to the optimized incorporation of any future advances in gene target prediction based on local sequence, genome layout or on novel criteria. With the current state of the art, PreCisIon consistently improves methods based on sequence information only. This is shown by implementing a cross-validation analysis of the 20 major TFs from two phylogenetically remote model organisms. For Bacillus subtilis and Escherichia coli, respectively, PreCisIon achieves on average an area under the receiver operating characteristic curve of 70 and 60%, a sensitivity of 80 and 70% and a specificity of 60 and 56%. The newly predicted gene targets are demonstrated to be functionally consistent with previously known targets, as assessed by analysis of Gene Ontology enrichment or of the relevant literature and databases. PMID:23241390

  4. Neural network incorporating meal information improves accuracy of short-time prediction of glucose concentration.

    PubMed

    Zecchin, Chiara; Facchinetti, Andrea; Sparacino, Giovanni; De Nicolao, Giuseppe; Cobelli, Claudio

    2012-06-01

    Diabetes mellitus is one of the most common chronic diseases, and a clinically important task in its management is the prevention of hypo/hyperglycemic events. This can be achieved by exploiting continuous glucose monitoring (CGM) devices and suitable short-term prediction algorithms able to infer future glycemia in real time. In the literature, several methods for short-time glucose prediction have been proposed, most of which do not exploit information on meals, and use past CGM readings only. In this paper, we propose an algorithm for short-time glucose prediction using past CGM sensor readings and information on carbohydrate intake. The predictor combines a neural network (NN) model and a first-order polynomial extrapolation algorithm, used in parallel to describe, respectively, the nonlinear and the linear components of glucose dynamics. Information on the glucose rate of appearance after a meal is described by a previously published physiological model. The method is assessed on 20 simulated datasets and on 9 real Abbott FreeStyle Navigator datasets, and its performance is successfully compared with that of a recently proposed NN glucose predictor. Results suggest that exploiting meal information improves the accuracy of short-time glucose prediction.

  5. Joint analysis of psychiatric disorders increases accuracy of risk prediction for schizophrenia, bipolar disorder, and major depressive disorder.

    PubMed

    Maier, Robert; Moser, Gerhard; Chen, Guo-Bo; Ripke, Stephan; Coryell, William; Potash, James B; Scheftner, William A; Shi, Jianxin; Weissman, Myrna M; Hultman, Christina M; Landén, Mikael; Levinson, Douglas F; Kendler, Kenneth S; Smoller, Jordan W; Wray, Naomi R; Lee, S Hong

    2015-02-05

    Genetic risk prediction has several potential applications in medical research and clinical practice and could be used, for example, to stratify a heterogeneous population of patients by their predicted genetic risk. However, for polygenic traits, such as psychiatric disorders, the accuracy of risk prediction is low. Here we use a multivariate linear mixed model and apply multi-trait genomic best linear unbiased prediction for genetic risk prediction. This method exploits correlations between disorders and simultaneously evaluates individual risk for each disorder. We show that the multivariate approach significantly increases the prediction accuracy for schizophrenia, bipolar disorder, and major depressive disorder in the discovery as well as in independent validation datasets. By grouping SNPs based on genome annotation and fitting multiple random effects, we show that the prediction accuracy could be further improved. The gain in prediction accuracy of the multivariate approach is equivalent to an increase in sample size of 34% for schizophrenia, 68% for bipolar disorder, and 76% for major depressive disorders using single trait models. Because our approach can be readily applied to any number of GWAS datasets of correlated traits, it is a flexible and powerful tool to maximize prediction accuracy. With current sample size, risk predictors are not useful in a clinical setting but already are a valuable research tool, for example in experimental designs comparing cases with high and low polygenic risk.

  6. Joint Analysis of Psychiatric Disorders Increases Accuracy of Risk Prediction for Schizophrenia, Bipolar Disorder, and Major Depressive Disorder

    PubMed Central

    Maier, Robert; Moser, Gerhard; Chen, Guo-Bo; Ripke, Stephan; Absher, Devin; Agartz, Ingrid; Akil, Huda; Amin, Farooq; Andreassen, Ole A.; Anjorin, Adebayo; Anney, Richard; Arking, Dan E.; Asherson, Philip; Azevedo, Maria H.; Backlund, Lena; Badner, Judith A.; Bailey, Anthony J.; Banaschewski, Tobias; Barchas, Jack D.; Barnes, Michael R.; Barrett, Thomas B.; Bass, Nicholas; Battaglia, Agatino; Bauer, Michael; Bayés, Mònica; Bellivier, Frank; Bergen, Sarah E.; Berrettini, Wade; Betancur, Catalina; Bettecken, Thomas; Biederman, Joseph; Binder, Elisabeth B.; Black, Donald W.; Blackwood, Douglas H.R.; Bloss, Cinnamon S.; Boehnke, Michael; Boomsma, Dorret I.; Breen, Gerome; Breuer, René; Bruggeman, Richard; Buccola, Nancy G.; Buitelaar, Jan K.; Bunney, William E.; Buxbaum, Joseph D.; Byerley, William F.; Caesar, Sian; Cahn, Wiepke; Cantor, Rita M.; Casas, Miguel; Chakravarti, Aravinda; Chambert, Kimberly; Choudhury, Khalid; Cichon, Sven; Cloninger, C. Robert; Collier, David A.; Cook, Edwin H.; Coon, Hilary; Cormand, Bru; Cormican, Paul; Corvin, Aiden; Coryell, William H.; Craddock, Nicholas; Craig, David W.; Craig, Ian W.; Crosbie, Jennifer; Cuccaro, Michael L.; Curtis, David; Czamara, Darina; Daly, Mark J.; Datta, Susmita; Dawson, Geraldine; Day, Richard; De Geus, Eco J.; Degenhardt, Franziska; Devlin, Bernie; Djurovic, Srdjan; Donohoe, Gary J.; Doyle, Alysa E.; Duan, Jubao; Dudbridge, Frank; Duketis, Eftichia; Ebstein, Richard P.; Edenberg, Howard J.; Elia, Josephine; Ennis, Sean; Etain, Bruno; Fanous, Ayman; Faraone, Stephen V.; Farmer, Anne E.; Ferrier, I. Nicol; Flickinger, Matthew; Fombonne, Eric; Foroud, Tatiana; Frank, Josef; Franke, Barbara; Fraser, Christine; Freedman, Robert; Freimer, Nelson B.; Freitag, Christine M.; Friedl, Marion; Frisén, Louise; Gallagher, Louise; Gejman, Pablo V.; Georgieva, Lyudmila; Gershon, Elliot S.; Geschwind, Daniel H.; Giegling, Ina; Gill, Michael; Gordon, Scott D.; Gordon-Smith, Katherine; Green, Elaine K.; Greenwood, Tiffany A.; Grice, Dorothy E.; Gross, Magdalena; Grozeva, Detelina; Guan, Weihua; Gurling, Hugh; De Haan, Lieuwe; Haines, Jonathan L.; Hakonarson, Hakon; Hallmayer, Joachim; Hamilton, Steven P.; Hamshere, Marian L.; Hansen, Thomas F.; Hartmann, Annette M.; Hautzinger, Martin; Heath, Andrew C.; Henders, Anjali K.; Herms, Stefan; Hickie, Ian B.; Hipolito, Maria; Hoefels, Susanne; Holmans, Peter A.; Holsboer, Florian; Hoogendijk, Witte J.; Hottenga, Jouke-Jan; Hultman, Christina M.; Hus, Vanessa; Ingason, Andrés; Ising, Marcus; Jamain, Stéphane; Jones, Ian; Jones, Lisa; Kähler, Anna K.; Kahn, René S.; Kandaswamy, Radhika; Keller, Matthew C.; Kelsoe, John R.; Kendler, Kenneth S.; Kennedy, James L.; Kenny, Elaine; Kent, Lindsey; Kim, Yunjung; Kirov, George K.; Klauck, Sabine M.; Klei, Lambertus; Knowles, James A.; Kohli, Martin A.; Koller, Daniel L.; Konte, Bettina; Korszun, Ania; Krabbendam, Lydia; Krasucki, Robert; Kuntsi, Jonna; Kwan, Phoenix; Landén, Mikael; Långström, Niklas; Lathrop, Mark; Lawrence, Jacob; Lawson, William B.; Leboyer, Marion; Ledbetter, David H.; Lee, Phil H.; Lencz, Todd; Lesch, Klaus-Peter; Levinson, Douglas F.; Lewis, Cathryn M.; Li, Jun; Lichtenstein, Paul; Lieberman, Jeffrey A.; Lin, Dan-Yu; Linszen, Don H.; Liu, Chunyu; Lohoff, Falk W.; Loo, Sandra K.; Lord, Catherine; Lowe, Jennifer K.; Lucae, Susanne; MacIntyre, Donald J.; Madden, Pamela A.F.; Maestrini, Elena; Magnusson, Patrik K.E.; Mahon, Pamela B.; Maier, Wolfgang; Malhotra, Anil K.; Mane, Shrikant M.; Martin, Christa L.; Martin, Nicholas G.; Mattheisen, Manuel; Matthews, Keith; Mattingsdal, Morten; McCarroll, Steven A.; McGhee, Kevin A.; McGough, James J.; McGrath, Patrick J.; McGuffin, Peter; McInnis, Melvin G.; McIntosh, Andrew; McKinney, Rebecca; McLean, Alan W.; McMahon, Francis J.; McMahon, William M.; McQuillin, Andrew; Medeiros, Helena; Medland, Sarah E.; Meier, Sandra; Melle, Ingrid; Meng, Fan; Meyer, Jobst; Middeldorp, Christel M.; Middleton, Lefkos; Milanova, Vihra; Miranda, Ana; Monaco, Anthony P.; Montgomery, Grant W.; Moran, Jennifer L.; Moreno-De-Luca, Daniel; Morken, Gunnar; Morris, Derek W.; Morrow, Eric M.; Moskvina, Valentina; Mowry, Bryan J.; Muglia, Pierandrea; Mühleisen, Thomas W.; Müller-Myhsok, Bertram; Murtha, Michael; Myers, Richard M.; Myin-Germeys, Inez; Neale, Benjamin M.; Nelson, Stan F.; Nievergelt, Caroline M.; Nikolov, Ivan; Nimgaonkar, Vishwajit; Nolen, Willem A.; Nöthen, Markus M.; Nurnberger, John I.; Nwulia, Evaristus A.; Nyholt, Dale R.; O’Donovan, Michael C.; O’Dushlaine, Colm; Oades, Robert D.; Olincy, Ann; Oliveira, Guiomar; Olsen, Line; Ophoff, Roel A.; Osby, Urban; Owen, Michael J.; Palotie, Aarno; Parr, Jeremy R.; Paterson, Andrew D.; Pato, Carlos N.; Pato, Michele T.; Penninx, Brenda W.; Pergadia, Michele L.; Pericak-Vance, Margaret A.; Perlis, Roy H.; Pickard, Benjamin S.; Pimm, Jonathan; Piven, Joseph; Posthuma, Danielle; Potash, James B.; Poustka, Fritz; Propping, Peter; Purcell, Shaun M.; Puri, Vinay; Quested, Digby J.; Quinn, Emma M.; Ramos-Quiroga, Josep Antoni; Rasmussen, Henrik B.; Raychaudhuri, Soumya; Rehnström, Karola; Reif, Andreas; Ribasés, Marta; Rice, John P.; Rietschel, Marcella; Ripke, Stephan; Roeder, Kathryn; Roeyers, Herbert; Rossin, Lizzy; Rothenberger, Aribert; Rouleau, Guy; Ruderfer, Douglas; Rujescu, Dan; Sanders, Alan R.; Sanders, Stephan J.; Santangelo, Susan L.; Schachar, Russell; Schalling, Martin; Schatzberg, Alan F.; Scheftner, William A.; Schellenberg, Gerard D.; Scherer, Stephen W.; Schork, Nicholas J.; Schulze, Thomas G.; Schumacher, Johannes; Schwarz, Markus; Scolnick, Edward; Scott, Laura J.; Sergeant, Joseph A.; Shi, Jianxin; Shilling, Paul D.; Shyn, Stanley I.; Silverman, Jeremy M.; Sklar, Pamela; Slager, Susan L.; Smalley, Susan L.; Smit, Johannes H.; Smith, Erin N.; Smoller, Jordan W.; Sonuga-Barke, Edmund J.S.; St Clair, David; State, Matthew; Steffens, Michael; Steinhausen, Hans-Christoph; Strauss, John S.; Strohmaier, Jana; Stroup, T. Scott; Sullivan, Patrick F.; Sutcliffe, James; Szatmari, Peter; Szelinger, Szabocls; Thapar, Anita; Thirumalai, Srinivasa; Thompson, Robert C.; Todorov, Alexandre A.; Tozzi, Federica; Treutlein, Jens; Tzeng, Jung-Ying; Uhr, Manfred; van den Oord, Edwin J.C.G.; Van Grootheest, Gerard; Van Os, Jim; Vicente, Astrid M.; Vieland, Veronica J.; Vincent, John B.; Visscher, Peter M.; Walsh, Christopher A.; Wassink, Thomas H.; Watson, Stanley J.; Weiss, Lauren A.; Weissman, Myrna M.; Werge, Thomas; Wienker, Thomas F.; Wiersma, Durk; Wijsman, Ellen M.; Willemsen, Gonneke; Williams, Nigel; Willsey, A. Jeremy; Witt, Stephanie H.; Wray, Naomi R.; Xu, Wei; Young, Allan H.; Yu, Timothy W.; Zammit, Stanley; Zandi, Peter P.; Zhang, Peng; Zitman, Frans G.; Zöllner, Sebastian; Coryell, William; Potash, James B.; Scheftner, William A.; Shi, Jianxin; Weissman, Myrna M.; Hultman, Christina M.; Landén, Mikael; Levinson, Douglas F.; Kendler, Kenneth S.; Smoller, Jordan W.; Wray, Naomi R.; Lee, S. Hong

    2015-01-01

    Genetic risk prediction has several potential applications in medical research and clinical practice and could be used, for example, to stratify a heterogeneous population of patients by their predicted genetic risk. However, for polygenic traits, such as psychiatric disorders, the accuracy of risk prediction is low. Here we use a multivariate linear mixed model and apply multi-trait genomic best linear unbiased prediction for genetic risk prediction. This method exploits correlations between disorders and simultaneously evaluates individual risk for each disorder. We show that the multivariate approach significantly increases the prediction accuracy for schizophrenia, bipolar disorder, and major depressive disorder in the discovery as well as in independent validation datasets. By grouping SNPs based on genome annotation and fitting multiple random effects, we show that the prediction accuracy could be further improved. The gain in prediction accuracy of the multivariate approach is equivalent to an increase in sample size of 34% for schizophrenia, 68% for bipolar disorder, and 76% for major depressive disorders using single trait models. Because our approach can be readily applied to any number of GWAS datasets of correlated traits, it is a flexible and powerful tool to maximize prediction accuracy. With current sample size, risk predictors are not useful in a clinical setting but already are a valuable research tool, for example in experimental designs comparing cases with high and low polygenic risk. PMID:25640677

  7. The contact caveat: negative contact predicts increased prejudice more than positive contact predicts reduced prejudice.

    PubMed

    Barlow, Fiona Kate; Paolini, Stefania; Pedersen, Anne; Hornsey, Matthew J; Radke, Helena R M; Harwood, Jake; Rubin, Mark; Sibley, Chris G

    2012-12-01

    Contact researchers have largely overlooked the potential for negative intergroup contact to increase prejudice. In Study 1, we tested the interaction between contact quantity and valence on prejudice toward Black Australians (n = 1,476), Muslim Australians (n = 173), and asylum seekers (n = 293). In all cases, the association between contact quantity and prejudice was moderated by its valence, with negative contact emerging as a stronger and more consistent predictor than positive contact. In Study 2, White Americans (n = 441) indicated how much positive and negative contact they had with Black Americans on separate measures. Although both quantity of positive and negative contact predicted racism and avoidance, negative contact was the stronger predictor. Furthermore, negative (but not positive) contact independently predicted suspicion about Barack Obama's birthplace. These results extend the contact hypothesis by issuing an important caveat: Negative contact may be more strongly associated with increased racism and discrimination than positive contact is with its reduction.

  8. The utility and accuracy of oral reading fluency score types in predicting reading comprehension.

    PubMed

    Petscher, Yaacov; Kim, Young-Suk

    2011-02-01

    This study used data from the Dynamic Indicators of Basic Early Literacy Skills (DIBELS; Good & Kaminski, 2002) oral reading fluency (ORF) probes to examine variation among different ORF score types (i.e., the median of three passages, the mean of all three passages, the mean of passages 2 and 3, and the score from passage 3) in predicting reading comprehension as a function of student reading fluency level and to compare the screening accuracy of these score types in predicting student reading comprehension. The results revealed that the relation between oral reading fluency and reading comprehension varied as a function of students' oral reading fluency and that different score types had varying predictive validity for year-end reading comprehension. The mean of all three passages demonstrated a marginally better balance in screening efficiency from September to December of grade one (especially for low-performing students), whereas in grades two and three, the median score was the best predictor. Furthermore, across all grades, increasing reading rates were observed for the three administered passages within an assessment period. The observed patterns mimicked previous experimental studies (Francis et al., 2008; Jenkins, Graff, & Miglioretti, 2009), suggesting that practice effects are an important consideration in the administration of multiple passages assessing oral reading fluency.

  9. ABodyBuilder: Automated antibody structure prediction with data–driven accuracy estimation

    PubMed Central

    Leem, Jinwoo; Dunbar, James; Georges, Guy; Shi, Jiye; Deane, Charlotte M.

    2016-01-01

    ABSTRACT Computational modeling of antibody structures plays a critical role in therapeutic antibody design. Several antibody modeling pipelines exist, but no freely available methods currently model nanobodies, provide estimates of expected model accuracy, or highlight potential issues with the antibody's experimental development. Here, we describe our automated antibody modeling pipeline, ABodyBuilder, designed to overcome these issues. The algorithm itself follows the standard 4 steps of template selection, orientation prediction, complementarity-determining region (CDR) loop modeling, and side chain prediction. ABodyBuilder then annotates the ‘confidence’ of the model as a probability that a component of the antibody (e.g., CDRL3 loop) will be modeled within a root–mean square deviation threshold. It also flags structural motifs on the model that are known to cause issues during in vitro development. ABodyBuilder was tested on 4 separate datasets, including the 11 antibodies from the Antibody Modeling Assessment–II competition. ABodyBuilder builds models that are of similar quality to other methodologies, with sub–Angstrom predictions for the ‘canonical’ CDR loops. Its ability to model nanobodies, and rapidly generate models (∼30 seconds per model) widens its potential usage. ABodyBuilder can also help users in decision–making for the development of novel antibodies because it provides model confidence and potential sequence liabilities. ABodyBuilder is freely available at http://opig.stats.ox.ac.uk/webapps/abodybuilder. PMID:27392298

  10. Diagnostic Accuracy of Optic Nerve Ultrasonography and Ophthalmoscopy in Prediction of Elevated Intracranial Pressure

    PubMed Central

    Golshani, Keihan; Ebrahim zadeh, Mehdi; Farajzadegan, Ziba; Khorvash, Fariborz

    2015-01-01

    Introduction: Elevated intracranial pressure (ICP) is a major and potentially lethal disorder in patients admitted to the emergency department (ED). Several methods are being used to investigate for elevated ICP. Here we assessed and compared the diagnostic accuracy of two existing tools of ophthalmoscopy and optic nerve ultrasonography in detection of elevated ICP. Methods: 131 participants with probable elevation of ICP referred to the emergency department of Al-Zahra Hospital, Isfahan, Iran, from 2012 to 2014, were enrolled. Brain computed tomography (CT) scan, ultrasonography of optic nerve sheath, and ophthalmoscopy were performed for them. The optic nerves sheath with diameter more than 5 millimeters was considered as elevated ICP. Widening of optic nerve, ocular venous engorgement, blurring, hemorrhage over optic disk, elevation of optic disk, and retinal venous tortuosity were recorded as evidences of ICP rising in ophthalmoscopy. Diagnostic accuracy of the two tools in prediction of ICP rising were compared with the results of brain CT scan as a gold standard. Results: The mean age of participants was 46.29 ± 10 years (77% male). The number of diagnosed elevated ICPs with ophthalmoscopy and ultrasound were 98 (74.8%) and 102 (77.9%) cases, respectively. The calculated sensitivity and specificity of ophthalmoscopy and ultrasonography in detection of ICP rising were 100.0% (95% CI: 88.6-100.0) and 35.4% (95% CI: 26.0-46.2), 100.0% (95% CI: 84.0-100.0) and 31.9% (95% CI: 23.0-41.7), respectively. Conclusion: The present study revealed that bedside ultrasonography of optic nerve sheath and ophthalmoscopy have enough accuracy for the screening of patients with probable elevation of ICP. Of course, it should be considered that despite the high sensitivity of both tools, their specificity is low. PMID:26495382

  11. Reconciling multiple data sources to improve accuracy of large-scale prediction of forest disease incidence

    USGS Publications Warehouse

    Hanks, E.M.; Hooten, M.B.; Baker, F.A.

    2011-01-01

    Ecological spatial data often come from multiple sources, varying in extent and accuracy. We describe a general approach to reconciling such data sets through the use of the Bayesian hierarchical framework. This approach provides a way for the data sets to borrow strength from one another while allowing for inference on the underlying ecological process. We apply this approach to study the incidence of eastern spruce dwarf mistletoe (Arceuthobium pusillum) in Minnesota black spruce (Picea mariana). A Minnesota Department of Natural Resources operational inventory of black spruce stands in northern Minnesota found mistletoe in 11% of surveyed stands, while a small, specific-pest survey found mistletoe in 56% of the surveyed stands. We reconcile these two surveys within a Bayesian hierarchical framework and predict that 35-59% of black spruce stands in northern Minnesota are infested with dwarf mistletoe. ?? 2011 by the Ecological Society of America.

  12. Integrated CFD and Controls Analysis Interface for High Accuracy Liquid Propellant Slosh Predictions

    NASA Technical Reports Server (NTRS)

    Marsell, Brandon; Griffin, David; Schallhorn, Paul; Roth, Jacob

    2012-01-01

    Coupling computational fluid dynamics (CFD) with a controls analysis tool elegantly allows for high accuracy predictions of the interaction between sloshing liquid propellants and the control system of a launch vehicle. Instead of relying on mechanical analogs which are n0t va lid during all stages of flight, this method allows for a direct link between the vehicle dynamic environments calculated by the solver in the controls analysis tool to the fluid now equations solved by the CFD code. This paper describes such a coupling methodology, presents the results of a series of test cases, and compares said results against equivalent results from extensively validated tools. The coupling methodology, described herein, has proven to be highly accurate in a variety of different cases.

  13. High Accuracy Liquid Propellant Slosh Predictions Using an Integrated CFD and Controls Analysis Interface

    NASA Technical Reports Server (NTRS)

    Marsell, Brandon; Griffin, David; Schallhorn, Dr. Paul; Roth, Jacob

    2012-01-01

    Coupling computational fluid dynamics (CFD) with a controls analysis tool elegantly allows for high accuracy predictions of the interaction between sloshing liquid propellants and th e control system of a launch vehicle. Instead of relying on mechanical analogs which are not valid during aU stages of flight, this method allows for a direct link between the vehicle dynamic environments calculated by the solver in the controls analysis tool to the fluid flow equations solved by the CFD code. This paper describes such a coupling methodology, presents the results of a series of test cases, and compares said results against equivalent results from extensively validated tools. The coupling methodology, described herein, has proven to be highly accurate in a variety of different cases.

  14. Accuracy and Calibration of Computational Approaches for Inpatient Mortality Predictive Modeling

    PubMed Central

    Nakas, Christos T.; Schütz, Narayan; Werners, Marcus; Leichtle, Alexander B.

    2016-01-01

    Electronic Health Record (EHR) data can be a key resource for decision-making support in clinical practice in the “big data” era. The complete database from early 2012 to late 2015 involving hospital admissions to Inselspital Bern, the largest Swiss University Hospital, was used in this study, involving over 100,000 admissions. Age, sex, and initial laboratory test results were the features/variables of interest for each admission, the outcome being inpatient mortality. Computational decision support systems were utilized for the calculation of the risk of inpatient mortality. We assessed the recently proposed Acute Laboratory Risk of Mortality Score (ALaRMS) model, and further built generalized linear models, generalized estimating equations, artificial neural networks, and decision tree systems for the predictive modeling of the risk of inpatient mortality. The Area Under the ROC Curve (AUC) for ALaRMS marginally corresponded to the anticipated accuracy (AUC = 0.858). Penalized logistic regression methodology provided a better result (AUC = 0.872). Decision tree and neural network-based methodology provided even higher predictive performance (up to AUC = 0.912 and 0.906, respectively). Additionally, decision tree-based methods can efficiently handle Electronic Health Record (EHR) data that have a significant amount of missing records (in up to >50% of the studied features) eliminating the need for imputation in order to have complete data. In conclusion, we show that statistical learning methodology can provide superior predictive performance in comparison to existing methods and can also be production ready. Statistical modeling procedures provided unbiased, well-calibrated models that can be efficient decision support tools for predicting inpatient mortality and assigning preventive measures. PMID:27414408

  15. Biased binomial assessment of cross-validated estimation of classification accuracies illustrated in diagnosis predictions.

    PubMed

    Noirhomme, Quentin; Lesenfants, Damien; Gomez, Francisco; Soddu, Andrea; Schrouff, Jessica; Garraux, Gaëtan; Luxen, André; Phillips, Christophe; Laureys, Steven

    2014-01-01

    Multivariate classification is used in neuroimaging studies to infer brain activation or in medical applications to infer diagnosis. Their results are often assessed through either a binomial or a permutation test. Here, we simulated classification results of generated random data to assess the influence of the cross-validation scheme on the significance of results. Distributions built from classification of random data with cross-validation did not follow the binomial distribution. The binomial test is therefore not adapted. On the contrary, the permutation test was unaffected by the cross-validation scheme. The influence of the cross-validation was further illustrated on real-data from a brain-computer interface experiment in patients with disorders of consciousness and from an fMRI study on patients with Parkinson disease. Three out of 16 patients with disorders of consciousness had significant accuracy on binomial testing, but only one showed significant accuracy using permutation testing. In the fMRI experiment, the mental imagery of gait could discriminate significantly between idiopathic Parkinson's disease patients and healthy subjects according to the permutation test but not according to the binomial test. Hence, binomial testing could lead to biased estimation of significance and false positive or negative results. In our view, permutation testing is thus recommended for clinical application of classification with cross-validation.

  16. The Annular Suspension and Pointing (ASP) system for space experiments and predicted pointing accuracies

    NASA Technical Reports Server (NTRS)

    Anderson, W. W.; Joshi, S. M.

    1975-01-01

    An annular suspension and pointing system consisting of pointing assemblies for coarse and vernier pointing is described. The first assembly is attached to a carrier spacecraft (e.g., the space shuttle) and consists of an azimuth gimbal and an elevation gimbal which provide 'coarse' pointing. The second or vernier pointing assembly is made up of magnetic actuators of suspension and fine pointing, roll motor segments, and an instrument or experiment mounting plate around which is attached a continuous annular rim similar to that used in the annular momentum control device. The rim provides appropriate magnetic circuits for the actuators and the roll motor segments for any instrument roll position. The results of a study to determine the pointing accuracy of the system in the presence of crew motion disturbances are presented. Typical 3 sigma worst-case errors are found to be of the order of 0.001 arc-second.

  17. Method to quantify accuracy of position feedback signals of a three-dimensional two-photon laser-scanning microscope

    PubMed Central

    Kummer, Michael; Kirmse, Knut; Witte, Otto W.; Haueisen, Jens; Holthoff, Knut

    2015-01-01

    Two-photon laser-scanning microscopy enables to record neuronal network activity in three-dimensional space while maintaining single-cellular resolution. One of the proposed approaches combines galvanometric x-y scanning with piezo-driven objective movements and employs hardware feedback signals for position monitoring. However, readily applicable methods to quantify the accuracy of those feedback signals are currently lacking. Here we provide techniques based on contact-free laser reflection and laser triangulation for the quantification of positioning accuracy of each spatial axis. We found that the lateral feedback signals are sufficiently accurate (defined as <2.5 µm) for a wide range of scan trajectories and frequencies. We further show that axial positioning accuracy does not only depend on objective acceleration and mass but also its geometry. We conclude that the introduced methods allow a reliable quantification of position feedback signals in a cost-efficient, easy-to-install manner and should be applicable for a wide range of two-photon laser scanning microscopes. PMID:26504620

  18. Method to quantify accuracy of position feedback signals of a three-dimensional two-photon laser-scanning microscope.

    PubMed

    Kummer, Michael; Kirmse, Knut; Witte, Otto W; Haueisen, Jens; Holthoff, Knut

    2015-10-01

    Two-photon laser-scanning microscopy enables to record neuronal network activity in three-dimensional space while maintaining single-cellular resolution. One of the proposed approaches combines galvanometric x-y scanning with piezo-driven objective movements and employs hardware feedback signals for position monitoring. However, readily applicable methods to quantify the accuracy of those feedback signals are currently lacking. Here we provide techniques based on contact-free laser reflection and laser triangulation for the quantification of positioning accuracy of each spatial axis. We found that the lateral feedback signals are sufficiently accurate (defined as <2.5 µm) for a wide range of scan trajectories and frequencies. We further show that axial positioning accuracy does not only depend on objective acceleration and mass but also its geometry. We conclude that the introduced methods allow a reliable quantification of position feedback signals in a cost-efficient, easy-to-install manner and should be applicable for a wide range of two-photon laser scanning microscopes.

  19. SU-E-J-118: Verification of Intrafractional Positional Accuracy Using Ultrasound Autoscan Tracking for Prostate Cancer Treatment

    SciTech Connect

    Yu, S; Hristov, D; Phillips, T

    2014-06-01

    Purpose: Transperineal ultrasound imaging is attractive option for imageguided radiation therapy as there is no need to implant fiducials, no extra imaging dose, and real time continuous imaging is possible during treatment. The aim of this study is to verify the tracking accuracy of a commercial ultrasound system under treatment conditions with a male pelvic phantom. Methods: A CT and ultrasound scan were acquired for the male pelvic phantom. The phantom was then placed in a treatment mimicking position on a motion platform. The axial and lateral tracking accuracy of the ultrasound system were verified using an independent optical tracking system. The tracking accuracy was evaluated by tracking the phantom position detected by the ultrasound system, and comparing it to the optical tracking system under the conditions of beam on (15 MV), beam off, poor image quality with an acoustic shadow introduced, and different phantom motion cycles (10 and 20 second periods). Additionally, the time lag between the ultrasound-detected and actual phantom motion was investigated. Results: Displacement amplitudes reported by the ultrasound system and optical system were within 0.5 mm of each other for both directions and all conditions. The ultrasound tracking performance in axial direction was better than in lateral direction. Radiation did not interfere with ultrasound tracking while image quality affected tracking accuracy. The tracking accuracy was better for periodic motion with 20 second period. The time delay between the ultrasound tracking system and the phantom motion was clinically acceptable. Conclusion: Intrafractional prostate motion is a potential source of treatment error especially in the context of emerging SBRT regimens. It is feasible to use transperineal ultrasound daily to monitor prostate motion during treatment. Our results verify the tracking accuracy of a commercial ultrasound system to be better than 1 mm under typical external beam treatment conditions.

  20. Accuracy of determination of position and width of molecular groups in biological and lipid membranes via neutron diffraction.

    PubMed

    Gordeliy, V I; Chernov, N I

    1997-07-01

    Neutron diffraction combined with the deuterium-labelled molecular groups of biological and model membrane components allows one to detect with high accuracy the structure of these objects. Experiments of this kind are only possible at unique high-flux neutron sources, and the planning of neutron-diffraction experiments must take into account some special requirements primarily related to the duration of the experiment and the accuracy of estimation of membrane structure parameters as a result of finite time of the measurements. This paper deals with the question of statistical accuracy of the position x(0) and width v of the distribution of deuterium labels in membranes along the normal of their plane, which are determined in a neutron diffraction experiment. It is shown that the accuracy of x(0) and v estimation does not depend on membrane constitution. It is dependent only on the scattering amplitude of the deuterium label, the label position x(0) and the distribution width v. Analytic calculations show that the statistical errors Deltax(0) and Deltav are inversely proportional to the scattering amplitude of the label and, as usual, to the square root of measurement time. The question of Deltax0 and Deltav dependence on the number of structure factors used in the calculations of x(0) and v is also studied. It is shown that, the accuracy of x(0) estimation is approximately constant with down to four structure factors used, and, with the number of the factors below four, it deteriorates drastically. Analogous is the behaviour of Deltav(h(max)) relation with one exception: abrupt deterioration of the accuracy occurs beginning with five structure factors used. One does not have to measure the highest diffraction reflections which takes a much longer time compared with the first ones. It is an important result. All the problems mentioned above have also been considered for the case of two different deuterium labels in membranes.

  1. The effects of relatedness and GxE interaction on prediction accuracies in genomic selection: a study in cassava

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prior to implementation of genomic selection, an evaluation of the potential accuracy of prediction can be obtained by cross validation. In this procedure, a population with both phenotypes and genotypes is split into training and validation sets. The prediction model is fitted using the training se...

  2. Accuracy of time comparison derived from reception of LORAN-C and Global Positioning System time signals.

    NASA Astrophysics Data System (ADS)

    Horiai, K.

    1992-10-01

    The accuracy of time comparison by means of the reception of common time signals, namely, LORAN-C and Global Positioning System (GPS), is examined. Differences of UTC from the emission times of these two radio wave signals measured at four Japanese stations and one U.S. station are analyzed and compared with the clock comparison reports published by the Bureau International des Poids et Mesures. The accuracy of the time comparison via LORAN-C signals of the northwest Pacific chain is about 3.61 μs and that via GPS is 0.14 μs. The accuracy analysis reveals the existence of systematic errors at the individual stations. In LORAN-C, the most serious error comes from those in the delay time calibration of receiving instruments and estimation of the propagation delay over land. Calibration of the clocks by a portable clock improves the accuracy of the GPS method to the accuracy of the GPS signals.

  3. Lean meat prediction with HGP, CGM and CSB-Image-Meater, with prediction accuracy evaluated for different proportions of gilts, boars and castrated boars in the pig population.

    PubMed

    Engel, B; Lambooij, E; Buist, W G; Vereijken, P

    2012-02-01

    Prediction equations for the percentage lean meat in pig carcasses in The Netherlands were derived for the Hennessy Grading Probe 7, Capteur Gras/Maigre--Sydel and CSB-Image-Meater. Because castrated males are expected to vanish from the Dutch pig population in the near future, accuracy of prediction was evaluated for different scenarios representing a wide range of different proportions for entire males, castrated males and females in the Dutch pig population. The prediction equations for the instruments are in compliance with the EC regulations for prediction accuracy for the different scenarios. So, these equations will remain valid when castrated males are (gradually) removed from the Dutch slaughter population. Results of this study are of interest for researchers from countries or areas contemplating the use of one of the aforementioned instruments. The statistical approach for evaluation of prediction accuracy is of particular interest when changes in proportions of important subpopulations in the target population are foreseen.

  4. Chasing probabilities - Signaling negative and positive prediction errors across domains.

    PubMed

    Meder, David; Madsen, Kristoffer H; Hulme, Oliver; Siebner, Hartwig R

    2016-07-01

    Adaptive actions build on internal probabilistic models of possible outcomes that are tuned according to the errors of their predictions when experiencing an actual outcome. Prediction errors (PEs) inform choice behavior across a diversity of outcome domains and dimensions, yet neuroimaging studies have so far only investigated such signals in singular experimental contexts. It is thus unclear whether the neuroanatomical distribution of PE encoding reported previously pertains to computational features that are invariant with respect to outcome valence, sensory domain, or some combination of the two. We acquired functional MRI data while volunteers performed four probabilistic reversal learning tasks which differed in terms of outcome valence (reward-seeking versus punishment-avoidance) and domain (abstract symbols versus facial expressions) of outcomes. We found that ventral striatum and frontopolar cortex coded increasingly positive PEs, whereas dorsal anterior cingulate cortex (dACC) traced increasingly negative PEs, irrespectively of the outcome dimension. Individual reversal behavior was unaffected by context manipulations and was predicted by activity in dACC and right inferior frontal gyrus (IFG). The stronger the response to negative PEs in these areas, the lower was the tendency to reverse choice behavior in response to negative events, suggesting that these regions enforce a rule-based strategy across outcome dimensions. Outcome valence influenced PE-related activity in left amygdala, IFG, and dorsomedial prefrontal cortex, where activity selectively scaled with increasingly positive PEs in the reward-seeking but not punishment-avoidance context, irrespective of sensory domain. Left amygdala displayed an additional influence of sensory domain. In the context of avoiding punishment, amygdala activity increased with increasingly negative PEs, but only for facial stimuli, indicating an integration of outcome valence and sensory domain during probabilistic

  5. At risk or not at risk? A meta-analysis of the prognostic accuracy of psychometric interviews for psychosis prediction

    PubMed Central

    Fusar-Poli, Paolo; Cappucciati, Marco; Rutigliano, Grazia; Schultze-Lutter, Frauke; Bonoldi, Ilaria; Borgwardt, Stefan; Riecher-Rössler, Anita; Addington, Jean; Perkins, Diana; Woods, Scott W; McGlashan, Thomas H; Lee, Jimmy; Klosterkötter, Joachim; Yung, Alison R; McGuire, Philip

    2015-01-01

    An accurate detection of individuals at clinical high risk (CHR) for psychosis is a prerequisite for effective preventive interventions. Several psychometric interviews are available, but their prognostic accuracy is unknown. We conducted a prognostic accuracy meta-analysis of psychometric interviews used to examine referrals to high risk services. The index test was an established CHR psychometric instrument used to identify subjects with and without CHR (CHR+ and CHR−). The reference index was psychosis onset over time in both CHR+ and CHR− subjects. Data were analyzed with MIDAS (STATA13). Area under the curve (AUC), summary receiver operating characteristic curves, quality assessment, likelihood ratios, Fagan’s nomogram and probability modified plots were computed. Eleven independent studies were included, with a total of 2,519 help-seeking, predominately adult subjects (CHR+: N=1,359; CHR−: N=1,160) referred to high risk services. The mean follow-up duration was 38 months. The AUC was excellent (0.90; 95% CI: 0.87-0.93), and comparable to other tests in preventive medicine, suggesting clinical utility in subjects referred to high risk services. Meta-regression analyses revealed an effect for exposure to antipsychotics and no effects for type of instrument, age, gender, follow-up time, sample size, quality assessment, proportion of CHR+ subjects in the total sample. Fagan’s nomogram indicated a low positive predictive value (5.74%) in the general non-help-seeking population. Albeit the clear need to further improve prediction of psychosis, these findings support the use of psychometric prognostic interviews for CHR as clinical tools for an indicated prevention in subjects seeking help at high risk services worldwide. PMID:26407788

  6. Accuracies of southwell and force/stiffness methods in the prediction of buckling strength of hypersonic aircraft wing tubular panels

    NASA Technical Reports Server (NTRS)

    Ko, William L.

    1987-01-01

    Accuracies of the Southwell method and the force/stiffness (F/S) method are examined when the methods were used in the prediction of buckling loads of hypersonic aircraft wing tubular panels, based on nondestructive buckling test data. Various factors affecting the accuracies of the two methods were discussed. Effects of load cutoff point in the nondestructive buckling tests on the accuracies of the two methods were discussed in great detail. For the tubular panels under pure compression, the F/S method was found to give more accurate buckling load predictions than the Southwell method, which excessively overpredicts the buckling load. It was found that the Southwell method required a higher load cutoff point, as compared with the F/S method. In using the F/S method for predicting the buckling load of tubular panels under pure compression, the load cutoff point of approximately 50 percent of the critical load could give reasonably accurate predictions.

  7. Accuracy of whole-genome prediction using a genetic architecture-enhanced variance-covariance matrix.

    PubMed

    Zhang, Zhe; Erbe, Malena; He, Jinlong; Ober, Ulrike; Gao, Ning; Zhang, Hao; Simianer, Henner; Li, Jiaqi

    2015-02-09

    Obtaining accurate predictions of unobserved genetic or phenotypic values for complex traits in animal, plant, and human populations is possible through whole-genome prediction (WGP), a combined analysis of genotypic and phenotypic data. Because the underlying genetic architecture of the trait of interest is an important factor affecting model selection, we propose a new strategy, termed BLUP|GA (BLUP-given genetic architecture), which can use genetic architecture information within the dataset at hand rather than from public sources. This is achieved by using a trait-specific covariance matrix ( T: ), which is a weighted sum of a genetic architecture part ( S: matrix) and the realized relationship matrix ( G: ). The algorithm of BLUP|GA (BLUP-given genetic architecture) is provided and illustrated with real and simulated datasets. Predictive ability of BLUP|GA was validated with three model traits in a dairy cattle dataset and 11 traits in three public datasets with a variety of genetic architectures and compared with GBLUP and other approaches. Results show that BLUP|GA outperformed GBLUP in 20 of 21 scenarios in the dairy cattle dataset and outperformed GBLUP, BayesA, and BayesB in 12 of 13 traits in the analyzed public datasets. Further analyses showed that the difference of accuracies for BLUP|GA and GBLUP significantly correlate with the distance between the T: and G: matrices. The new strategy applied in BLUP|GA is a favorable and flexible alternative to the standard GBLUP model, allowing to account for the genetic architecture of the quantitative trait under consideration when necessary. This feature is mainly due to the increased similarity between the trait-specific relationship matrix ( T: matrix) and the genetic relationship matrix at unobserved causal loci. Applying BLUP|GA in WGP would ease the burden of model selection.

  8. Accuracy of continuous noninvasive hemoglobin monitoring for the prediction of blood transfusions in trauma patients.

    PubMed

    Galvagno, Samuel M; Hu, Peter; Yang, Shiming; Gao, Cheng; Hanna, David; Shackelford, Stacy; Mackenzie, Colin

    2015-12-01

    HR, SpHb and SpO2) for the prediction of blood products within the first 3 h of admission. When data from 15 min of continuous monitoring were analyzed, significant improvement in AUROC occurred as more variables were added to the model; however, the addition of SpHb to any of the models did not improve AUROC significantly for prediction of blood use within the first 3 h of admission in comparison to analysis of conventional oximetry features. The results demonstrate that SpHb monitoring, accompanied by continuous vital signs data and adjusted for age and sex, has good accuracy for the prediction of need for transfusion; however, as an independent variable, SpHb did not enhance predictive models in comparison to use of features extracted from conventional pulse oximetry. Nor was shock index better than conventional oximetry at discriminating hemorrhaging and prediction of casualties receiving blood. In this population of trauma patients, noninvasive SpHb monitoring, including both trends and absolute values, did not enhance the ability to predict the need for blood transfusion.

  9. Predictive Accuracy of Urinary neutrophil gelatinase associated lipocalin (NGAL) for renal parenchymal involvement in Children with Acute Pyelonephritis

    PubMed Central

    Ghasemi, Kambiz; Esteghamati, Maryam; Borzoo, Sara; Parvaneh, Erfan; Borzoo, Samira

    2016-01-01

    Introduction Urinary tract infections (UTIs) are among the most prevalent infections in children and infants. Early and accurate detection of renal parenchymal involvement in UTI is necessary for decision making and determining treatment strategies. The aim of this study was to determine the predictive accuracy of urinary neutrophil gelatinase-associated lipocalin (NGAL) for renal parenchymal involvement in children with acute pyelonephritis. Methods This descriptive, cross-sectional study was conducted in 2014 on children who had been diagnosed with UTI. Children who were admitted to Koodakan Hospital in Bandar Abbas, Hormozgan Province, Iran, and whose ages ranged from two months to 14 years were enrolled in the study. Urine samples were taken to conduct urinary NGAL tests, urine cultures, and urinalyses. In addition, some blood samples were collected for the purpose of determining leukocyte count and C-reactive protein (CRP) and to conduct erythrocyte sedimentation rate (ESR) tests. All patients underwent a dimercaptosuccinic acid (DMSA) scan. SPSS software was used to analyze the data. Results Among the participants in the study, 29 were male (32%), and 60 were female (68%). The mean age of the children who participated in the study was 2.99 ± 2.94 years. The results of the Kruskal-Wallis test showed a significant increase in the urinary NGAL level, an increase in the CRP level, and higher DMSA scan grades (p < 0.001). The cutoff point amounted to > 5 mg/l, having the negative predictive value (NPV) of 76.3%, the specificity of 97.83%, the positive predictive value (PPV) of 96.7%, and the sensitivity of 67.4%. Conclusion Urinary NGAL is not sensitive enough for the prediction of renal parenchymal involvement, but it is a specific marker. PMID:27053998

  10. Development of a Heterogeneous sUAS High-Accuracy Positional Flight Data Acquisition System

    NASA Technical Reports Server (NTRS)

    McSwain, Robert G.; Grosveld, Ferdinand W.

    2016-01-01

    Recently, a heterogeneous FDAS, consisting of a diverse range of instruments was developed to support acoustic flight research programs at NASA Langley Research Center. In addition to a conventional GPS to measure latitude, longitude and altitude, the FDAS also utilizes a small, light-weight, low-cost DGPS system to obtain centimeter accuracy to measure the distance traveled by sound from a sUAS vehicle to a microphone on the ground. Acoustic flight testing using the FDAS installed on several different sUAS platforms has been conducted in support of the NASA CAS DELIVER and ERA ITD projects (Reference 1). The first FDAS prototype was assembled and implemented in the acoustic/flight measurement system in December 2014 to support DELIVER acoustic flight tests. Evaluation of the system performance and results from the data analyses were used to further test, develop and enhance the FDAS over a six-month period to support acoustic flight research for the ERA.

  11. Examination of the Position Accuracy of Implant Abutments Reproduced by Intra-Oral Optical Impression

    PubMed Central

    Odaira, Chikayuki; Kobayashi, Takuya; Kondo, Hisatomo

    2016-01-01

    An impression technique called optical impression using intraoral scanner has attracted attention in digital dentistry. This study aimed to evaluate the accuracy of the optical impression, comparing a virtual model reproduced by an intraoral scanner to a working cast made by conventional silicone impression technique. Two implants were placed on a master model. Working casts made of plaster were fabricated from the master model by silicone impression. The distance between the ball abutments and the angulation between the healing abutments of 5 mm and 7 mm height at master model were measured using Computer Numerical Control Coordinate Measuring Machine (CNCCMM) as control. Working casts were then measured using CNCCMM, and virtual models via stereo lithography data of master model were measured by a three-dimensional analyzing software. The distance between ball abutments of the master model was 9634.9 ± 1.2 μm. The mean values of trueness of the Lava COS and working casts were 64.5 μm and 22.5 μm, respectively, greater than that of control. The mean of precision values of the Lava COS and working casts were 15.6 μm and 13.5 μm, respectively. In the case of a 5-mm-height healing abutment, mean angulation error of the Lava COS was greater than that of the working cast, resulting in significant differences in trueness and precision. However, in the case of a 7-mm-height abutment, mean angulation errors of the Lava COS and the working cast were not significantly different in trueness and precision. Therefore, distance errors of the optical impression were slightly greater than those of conventional impression. Moreover, the trueness and precision of angulation error could be improved in the optical impression using longer healing abutments. In the near future, the development of information technology could enable improvement in the accuracy of the optical impression with intraoral scanners. PMID:27706225

  12. Sampling multiple scoring functions can improve protein loop structure prediction accuracy.

    PubMed

    Li, Yaohang; Rata, Ionel; Jakobsson, Eric

    2011-07-25

    Accurately predicting loop structures is important for understanding functions of many proteins. In order to obtain loop models with high accuracy, efficiently sampling the loop conformation space to discover reasonable structures is a critical step. In loop conformation sampling, coarse-grain energy (scoring) functions coupling with reduced protein representations are often used to reduce the number of degrees of freedom as well as sampling computational time. However, due to implicitly considering many factors by reduced representations, the coarse-grain scoring functions may have potential insensitivity and inaccuracy, which can mislead the sampling process and consequently ignore important loop conformations. In this paper, we present a new computational sampling approach to obtain reasonable loop backbone models, so-called the Pareto optimal sampling (POS) method. The rationale of the POS method is to sample the function space of multiple, carefully selected scoring functions to discover an ensemble of diversified structures yielding Pareto optimality to all sampled conformations. The POS method can efficiently tolerate insensitivity and inaccuracy in individual scoring functions and thereby lead to significant accuracy improvement in loop structure prediction. We apply the POS method to a set of 4-12-residue loop targets using a function space composed of backbone-only Rosetta and distance-scale finite ideal-gas reference (DFIRE) and a triplet backbone dihedral potential developed in our lab. Our computational results show that in 501 out of 502 targets, the model sets generated by POS contain structure models are within subangstrom resolution. Moreover, the top-ranked models have a root mean square deviation (rmsd) less than 1 A in 96.8, 84.1, and 72.2% of the short (4-6 residues), medium (7-9 residues), and long (10-12 residues) targets, respectively, when the all-atom models are generated by local optimization from the backbone models and are ranked by our

  13. Tracking Accuracy of a Real-Time Fiducial Tracking System for Patient Positioning and Monitoring in Radiation Therapy

    SciTech Connect

    Shchory, Tal; Schifter, Dan; Lichtman, Rinat; Neustadter, David; Corn, Benjamin W.

    2010-11-15

    Purpose: In radiation therapy there is a need to accurately know the location of the target in real time. A novel radioactive tracking technology has been developed to answer this need. The technology consists of a radioactive implanted fiducial marker designed to minimize migration and a linac mounted tracking device. This study measured the static and dynamic accuracy of the new tracking technology in a clinical radiation therapy environment. Methods and Materials: The tracking device was installed on the linac gantry. The radioactive marker was located in a tissue equivalent phantom. Marker location was measured simultaneously by the radioactive tracking system and by a Microscribe G2 coordinate measuring machine (certified spatial accuracy of 0.38 mm). Localization consistency throughout a volume and absolute accuracy in the Fixed coordinate system were measured at multiple gantry angles over volumes of at least 10 cm in diameter centered at isocenter. Dynamic accuracy was measured with the marker located inside a breathing phantom. Results: The mean consistency for the static source was 0.58 mm throughout the tested region at all measured gantry angles. The mean absolute position error in the Fixed coordinate system for all gantry angles was 0.97 mm. The mean real-time tracking error for the dynamic source within the breathing phantom was less than 1 mm. Conclusions: This novel radioactive tracking technology has the potential to be useful in accurate target localization and real-time monitoring for radiation therapy.

  14. Attentional Bias towards Positive Emotion Predicts Stress Resilience.

    PubMed

    Thoern, Hanna A; Grueschow, Marcus; Ehlert, Ulrike; Ruff, Christian C; Kleim, Birgit

    2016-01-01

    There is extensive evidence for an association between an attentional bias towards emotionally negative stimuli and vulnerability to stress-related psychopathology. Less is known about whether selective attention towards emotionally positive stimuli relates to mental health and stress resilience. The current study used a modified Dot Probe task to investigate if individual differences in attentional biases towards either happy or angry emotional stimuli, or an interaction between these biases, are related to self-reported trait stress resilience. In a nonclinical sample (N = 43), we indexed attentional biases as individual differences in reaction time for stimuli preceded by either happy or angry (compared to neutral) face stimuli. Participants with greater attentional bias towards happy faces (but not angry faces) reported higher trait resilience. However, an attentional bias towards angry stimuli moderated this effect: The attentional bias towards happy faces was only predictive for resilience in those individuals who also endorsed an attentional bias towards angry stimuli. An attentional bias towards positive emotional stimuli may thus be a protective factor contributing to stress resilience, specifically in those individuals who also endorse an attentional bias towards negative emotional stimuli. Our findings therefore suggest a novel target for prevention and treatment interventions addressing stress-related psychopathology.

  15. Novel Genetic Analysis for Case-Control Genome-Wide Association Studies: Quantification of Power and Genomic Prediction Accuracy

    PubMed Central

    Lee, Sang Hong; Wray, Naomi R.

    2013-01-01

    Genome-wide association studies (GWAS) are routinely conducted for both quantitative and binary (disease) traits. We present two analytical tools for use in the experimental design of GWAS. Firstly, we present power calculations quantifying power in a unified framework for a range of scenarios. In this context we consider the utility of quantitative scores (e.g. endophenotypes) that may be available on cases only or both cases and controls. Secondly, we consider, the accuracy of prediction of genetic risk from genome-wide SNPs and derive an expression for genomic prediction accuracy using a liability threshold model for disease traits in a case-control design. The expected values based on our derived equations for both power and prediction accuracy agree well with observed estimates from simulations. PMID:23977056

  16. Evaluation of the soil moisture prediction accuracy of a space radar using simulation techniques. [Kansas

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T. (Principal Investigator); Dobson, M. C.; Stiles, J. A.; Moore, R. K.; Holtzman, J. C.

    1981-01-01

    Image simulation techniques were employed to generate synthetic aperture radar images of a 17.7 km x 19.3 km test site located east of Lawrence, Kansas. The simulations were performed for a space SAR at an orbital altitude of 600 km, with the following sensor parameters: frequency = 4.75 GHz, polarization = HH, and angle of incidence range = 7 deg to 22 deg from nadir. Three sets of images were produced corresponding to three different spatial resolutions; 20 m x 20 m with 12 looks, 100 m x 100 m with 23 looks, and 1 km x 1 km with 1000 looks. Each set consisted of images for four different soil moisture distributions across the test site. Results indicate that, for the agricultural portion of the test site, the soil moisture in about 90% of the pixels can be predicted with an accuracy of = + or - 20% of field capacity. Among the three spatial resolutions, the 1 km x 1 km resolution gave the best results for most cases, however, for very dry soil conditions, the 100 m x 100 m resolution was slightly superior.

  17. Improving the predictive accuracy of hurricane power outage forecasts using generalized additive models.

    PubMed

    Han, Seung-Ryong; Guikema, Seth D; Quiring, Steven M

    2009-10-01

    Electric power is a critical infrastructure service after hurricanes, and rapid restoration of electric power is important in order to minimize losses in the impacted areas. However, rapid restoration of electric power after a hurricane depends on obtaining the necessary resources, primarily repair crews and materials, before the hurricane makes landfall and then appropriately deploying these resources as soon as possible after the hurricane. This, in turn, depends on having sound estimates of both the overall severity of the storm and the relative risk of power outages in different areas. Past studies have developed statistical, regression-based approaches for estimating the number of power outages in advance of an approaching hurricane. However, these approaches have either not been applicable for future events or have had lower predictive accuracy than desired. This article shows that a different type of regression model, a generalized additive model (GAM), can outperform the types of models used previously. This is done by developing and validating a GAM based on power outage data during past hurricanes in the Gulf Coast region and comparing the results from this model to the previously used generalized linear models.

  18. Predicting the accuracy of facial affect recognition: the interaction of child maltreatment and intellectual functioning.

    PubMed

    Shenk, Chad E; Putnam, Frank W; Noll, Jennie G

    2013-02-01

    Previous research demonstrates that both child maltreatment and intellectual performance contribute uniquely to the accurate identification of facial affect by children and adolescents. The purpose of this study was to extend this research by examining whether child maltreatment affects the accuracy of facial recognition differently at varying levels of intellectual functioning. A sample of maltreated (n=50) and nonmaltreated (n=56) adolescent females, 14 to 19 years of age, was recruited to participate in this study. Participants completed demographic and study-related questionnaires and interviews to control for potential psychological and psychiatric confounds such as symptoms of posttraumatic stress disorder, negative affect, and difficulties in emotion regulation. Participants also completed an experimental paradigm that recorded responses to facial affect displays starting in a neutral expression and changing into a full expression of one of six emotions: happiness, sadness, anger, disgust, fear, or surprise. Hierarchical multiple regression assessed the incremental advantage of evaluating the interaction between child maltreatment and intellectual functioning. Results indicated that the interaction term accounted for a significant amount of additional variance in the accurate identification of facial affect after controlling for relevant covariates and main effects. Specifically, maltreated females with lower levels of intellectual functioning were least accurate in identifying facial affect displays, whereas those with higher levels of intellectual functioning performed as well as nonmaltreated females. These results suggest that maltreatment and intellectual functioning interact to predict the recognition of facial affect, with potential long-term consequences for the interpersonal functioning of maltreated females.

  19. The impact of climate change on the accuracy of streamflow predictions in California

    NASA Astrophysics Data System (ADS)

    Leonardson, R.; Vicuna, S.; Dracup, J. A.; Dale, L. L.

    2005-12-01

    Every spring, California's Department of Water Resources (DWR) forecasts streamflow for the upcoming irrigation season (April-July) for rivers fed by the Western Sierra snowpack. The DWR forecasts influence water allocations, cropping strategy, and flood and drought management plans; forecast error can impact California's economy, especially the agricultural sector. Demand for water is expected to increase with population growth and climate change effects, in which the summers will be longer and hotter. At the same time, the percentage of precipitation falling as snow will shrink, and the snowpack is expected to melt earlier. We expect both of these factors to reduce forecast accuracy, as forecasting rainfall is less precise than measuring snowpack and because less of the snowpack will remain after April 1st. In this study, we examine relationships between historical forecast error and watershed elevation, snowpack size, snowmelt timing (as hydrograph center-of-mass), and other factors. We quantify expected future error using the predictions of multiple global circulation models and various emissions scenarios.

  20. Relationship of hand preference to accuracy on a thumb-positioning task.

    PubMed

    Riolo-Quinn, L

    1991-08-01

    This study was designed to examine the relationship of hand preference to performance on a thumb-positioning task. Two hypotheses were proposed on the basis of hemispheric lateralization. The first stated that all subjects would perform the task more accurately using the left thumb, regardless of hand preference. The second hypothesis tested was that left-handed subjects would perform more accurately than right-handed subjects. Each of 20 neurologically intact adults grouped by hand preference reproduced a criterion thumb position with both thumbs simultaneously. Absolute error, recorded for each movement and analyzed by mixed analysis of variance, did support the first hypothesis. However, the left-handed group did not perform statistically differently from right-handed subjects. Factors influencing the data are discussed and recommendations for further studies are made.

  1. An investigation of airborne GPS/INS for high accuracy position and velocity determination

    SciTech Connect

    Sun, H.; Cannon, M.E.; Owen, T.E.; Meindl, M.A.

    1993-12-31

    An airborne test using a differential GPS-INS system in a Twin Otter was conducted by Sandia National Laboratories to assess the feasibility of using the integrated system for cm-level position and cm/s velocity. The INS is a miniaturized ring-laser gyro IMU jointly developed by Sandia and Honeywell while the GPS system consists of the NovAtel GPSCard{trademark}. INS position, velocity and attitude data were computed using Sandia`s SANDAC flight computer system and logged at 4 Hz and GPS data was acquired at a 1 Hz rate. The mission was approximately 2.5 hours in duration and the aircraft reached separations of up to 19 km from the base station. The data was post-processed using a centralized Kalman filter approach in which the double differenced carrier phase measurements are used to update the INS data. The INS position is in turn used to detect and correct GPS carrier phase cycle slips and also to bridge GPS outages. Results are presented for the GPS-only case and also for integrated GPS/INS.

  2. Sharp Chandra View of ROSAT All-Sky Survey Bright Sources — I. Improvement of Positional Accuracy

    NASA Astrophysics Data System (ADS)

    Gao, Shuang; Wang, Song; Liu, Ji-Feng

    2016-12-01

    The ROSAT All-Sky Survey (RASS) represents one of the most complete and sensitive soft X-ray all-sky surveys to date. However, the deficient positional accuracy of the RASS Bright Source Catalog (BSC) and subsequent lack of firm optical identifications affect multi-wavelength studies of X-ray sources. The widely used positional errors σpos based on the Tycho Reference Catalog (Tycho-1) have previously been applied for identifying objects in the optical band. The considerably sharper Chandra view covers a fraction of RASS sources, whose σpos could be improved by utilizing the sub-arcsec positional accuracy of Chandra observations. We cross-match X-ray objects between the BSC and Chandra sources extracted from the Advanced CCD Imaging Spectrometer (ACIS) archival observations. A combined list of counterparts (BSCxACIS) with Chandra spatial positions weighted by the X-ray flux of multiple counterparts is employed to evaluate and improve the former identifications of BSC when used with other surveys. Based on these identification evaluations, we suggest that the point-source likeness of BSC sources and INS (isolated neutron star) candidates should be carefully reconsidered.

  3. Changing within-trial array location and target object position enhances rats' (Rattus norvegicus) missing object recognition accuracy.

    PubMed

    Arain, Marium; Parameswaran, Varakini; Cohen, Jerome

    2012-09-01

    Six rats were trained to find a previously missing target or 'jackpot' object in a square array of four identical or different objects (the test segment of a trial) after first visiting and collecting sunflower seeds from under the other three objects (the study segment of a trial). During training, objects' local positions within the array and their global positions within the larger foraging array were varied over trials but were not changed between segments within a trial. Following this training, rats were tested on their accuracy for finding the target object when a trial's test array was sometimes moved to a different location in the foraging arena or when the position of the target object within the test array had been changed. Either of these manipulations initially slightly reduced rats' accuracy for finding the missing object but then enhanced it. Relocating test arrays of identical objects enhanced rats' performance only after 10-min inter-segment intervals (ISIs). Relocating test arrays of different objects enhanced rats' performance only after 2-min ISIs. Rats also improved their performance when they encountered the target object in a new position in test arrays of different objects. This enhancement effect occurred after either 2- or 30-min ISIs. These findings suggest that rats separately retrieved a missing (target) object's spatial and non-spatial information when they were relevant but not when they were irrelevant in a trial. The enhancement effects provide evidence for rats' limited retrieval capacity in their visuo-spatial working memory.

  4. The effects of demography and long-term selection on the accuracy of genomic prediction with sequence data.

    PubMed

    MacLeod, Iona M; Hayes, Ben J; Goddard, Michael E

    2014-12-01

    The use of dense SNPs to predict the genetic value of an individual for a complex trait is often referred to as "genomic selection" in livestock and crops, but is also relevant to human genetics to predict, for example, complex genetic disease risk. The accuracy of prediction depends on the strength of linkage disequilibrium (LD) between SNPs and causal mutations. If sequence data were used instead of dense SNPs, accuracy should increase because causal mutations are present, but demographic history and long-term negative selection also influence accuracy. We therefore evaluated genomic prediction, using simulated sequence in two contrasting populations: one reducing from an ancestrally large effective population size (Ne) to a small one, with high LD common in domestic livestock, while the second had a large constant-sized Ne with low LD similar to that in some human or outbred plant populations. There were two scenarios in each population; causal variants were either neutral or under long-term negative selection. For large Ne, sequence data led to a 22% increase in accuracy relative to ∼600K SNP chip data with a Bayesian analysis and a more modest advantage with a BLUP analysis. This advantage increased when causal variants were influenced by negative selection, and accuracy persisted when 10 generations separated reference and validation populations. However, in the reducing Ne population, there was little advantage for sequence even with negative selection. This study demonstrates the joint influence of demography and selection on accuracy of prediction and improves our understanding of how best to exploit sequence for genomic prediction.

  5. Detecting recent positive selection with high accuracy and reliability by conditional coalescent tree.

    PubMed

    Wang, Minxian; Huang, Xin; Li, Ran; Xu, Hongyang; Jin, Li; He, Yungang

    2014-11-01

    Studies of natural selection, followed by functional validation, are shedding light on understanding of genetic mechanisms underlying human evolution and adaptation. Classic methods for detecting selection, such as the integrated haplotype score (iHS) and Fay and Wu's H statistic, are useful for candidate gene searching underlying positive selection. These methods, however, have limited capability to localize causal variants in selection target regions. In this study, we developed a novel method based on conditional coalescent tree to detect recent positive selection by counting unbalanced mutations on coalescent gene genealogies. Extensive simulation studies revealed that our method is more robust than many other approaches against biases due to various demographic effects, including population bottleneck, expansion, or stratification, while not sacrificing its power. Furthermore, our method demonstrated its superiority in localizing causal variants from massive linked genetic variants. The rate of successful localization was about 20-40% higher than that of other state-of-the-art methods on simulated data sets. On empirical data, validated functional causal variants of four well-known positive selected genes were all successfully localized by our method, such as ADH1B, MCM6, APOL1, and HBB. Finally, the computational efficiency of this new method was much higher than that of iHS implementations, that is, 24-66 times faster than the REHH package, and more than 10,000 times faster than the original iHS implementation. These magnitudes make our method suitable for applying on large sequencing data sets. Software can be downloaded from https://github.com/wavefancy/scct.

  6. Impact of fitting dominance and additive effects on accuracy of genomic prediction of breeding values in layers.

    PubMed

    Heidaritabar, M; Wolc, A; Arango, J; Zeng, J; Settar, P; Fulton, J E; O'Sullivan, N P; Bastiaansen, J W M; Fernando, R L; Garrick, D J; Dekkers, J C M

    2016-10-01

    Most genomic prediction studies fit only additive effects in models to estimate genomic breeding values (GEBV). However, if dominance genetic effects are an important source of variation for complex traits, accounting for them may improve the accuracy of GEBV. We investigated the effect of fitting dominance and additive effects on the accuracy of GEBV for eight egg production and quality traits in a purebred line of brown layers using pedigree or genomic information (42K single-nucleotide polymorphism (SNP) panel). Phenotypes were corrected for the effect of hatch date. Additive and dominance genetic variances were estimated using genomic-based [genomic best linear unbiased prediction (GBLUP)-REML and BayesC] and pedigree-based (PBLUP-REML) methods. Breeding values were predicted using a model that included both additive and dominance effects and a model that included only additive effects. The reference population consisted of approximately 1800 animals hatched between 2004 and 2009, while approximately 300 young animals hatched in 2010 were used for validation. Accuracy of prediction was computed as the correlation between phenotypes and estimated breeding values of the validation animals divided by the square root of the estimate of heritability in the whole population. The proportion of dominance variance to total phenotypic variance ranged from 0.03 to 0.22 with PBLUP-REML across traits, from 0 to 0.03 with GBLUP-REML and from 0.01 to 0.05 with BayesC. Accuracies of GEBV ranged from 0.28 to 0.60 across traits. Inclusion of dominance effects did not improve the accuracy of GEBV, and differences in their accuracies between genomic-based methods were small (0.01-0.05), with GBLUP-REML yielding higher prediction accuracies than BayesC for egg production, egg colour and yolk weight, while BayesC yielded higher accuracies than GBLUP-REML for the other traits. In conclusion, fitting dominance effects did not impact accuracy of genomic prediction of breeding values in

  7. Education Level Predicts Retrospective Metamemory Accuracy in Healthy Aging and Alzheimer’s Disease

    PubMed Central

    Szajer, Jacquelyn; Murphy, Claire

    2013-01-01

    The current study investigated the effect of education on retrospective metamemory accuracy in 143 healthy older adults and 143 early to moderate AD patients, using retrospective measures of confidence in the accuracy of retrieval responses in an episodic odor recognition memory task. Relative confidence accuracy was computed as the difference between confidence judgments for correct and incorrect responses. In both AD patients and controls, individuals reporting 17 years of education or more had significantly more accurate levels of confidence than individuals with 12 years or less. Thus, education was a significant predictor of retrospective metamemory accuracy in healthy aging and AD. PMID:24131064

  8. Direct measurement of the position accuracy for low energy X-ray photons with a pnCCD

    NASA Astrophysics Data System (ADS)

    Ihle, S.; Holl, P.; Kalok, D.; Hartmann, R.; Ryll, H.; Steigenhöfer, D.; Strüder, L.

    2017-02-01

    We undertook a comparative study on optimizing the position accuracy of pnCCDs for single X-ray photon measurements. Various methods were analyzed by Monte Carlo simulations and related to experimental data obtained with a focused X-ray beam. Even with low energy photons of 1320 eV, a position accuracy much smaller than the actual pixel size of 48 μm × 48 μm can be achieved. This is possible since signal charges from a single photon interaction spread into more than one pixel, allowing a reconstruction of the original point of interaction. We found that a) making a decision on which pixels to use for the reconstruction and b) choosing a centroiding algorithm for carrying out the reconstruction were particularly crucial. For a) we introduce a new and superior method using a two step analysis with an adaptive pattern. It is compared to using a threshold or a fixed pattern. For b) we present a Center-of-Gravity method with a Gaussian correction taking into account the shape of the signal charge cloud. Both methods are also optimized for fast execution by implementing lookup tables rather than time consuming calculations. Our results show that with the appropriate analysis an uncertainty of the position measurement of better than 3.0 μm rms for 1320 eV photons is possible.

  9. Evaluation of the Positional Accuracy and Dosimetric Properties of a Three-dimensional Printed Device for Head and Neck Immobilization.

    PubMed

    Sato, Kiyokazu; Takeda, Ken; Dobashi, Suguru; Kadoya, Noriyuki; Ito, Kengo; Chiba, Mizuki; Kishi, Kazuma; Yanagawa, Isao; Jingu, Keiichi

    2017-01-01

    Our aim was to investigate the feasibility of a three-dimensional (3D) -printed head-and-neck (HN) immobilization device by comparing its positional accuracy and dosimetric properties with those of a conventional immobilization device (CID). We prepared a 3D-printed immobilization device (3DID) consisting of a mask and headrest with acrylonitrile-butadiene-styrene resin developed from the computed tomography data obtained by imaging a HN phantom. For comparison, a CID comprising a thermoplastic mask and headrest was prepared using the same HN phantom. We measured the setup error using the ExacTrac X-ray image system. Furthermore, using the ionization chamber and the water-equivalent phantom, we measured the changes in the dose due to the difference in the immobilization device material from the photon of 4 MV and 6 MV. The positional accuracy of the two devices were almost similar in each direction except in the vertical, lateral, and pitch directions (t-test, p<0.0001), and the maximum difference was 1 mm, and 1°. The standard deviations were not statistically different in each direction except in the longitudinal (F-test, p=0.034) and roll directions (F-test, p<0.0001). When the thickness was the same, the dose difference was almost similar at a 50 mm depth. At a 1 mm depth, the 3DID-plate had a 2.9-4.2% lower dose than the CID-plate. This study suggested that the positional accuracy and dosimetric properties of 3DID were almost similar to those of CID.

  10. Accuracy of the DIBELS oral reading fluency measure for predicting third grade reading comprehension outcomes.

    PubMed

    Roehrig, Alysia D; Petscher, Yaacov; Nettles, Stephen M; Hudson, Roxanne F; Torgesen, Joseph K

    2008-06-01

    We evaluated the validity of DIBELS (Dynamic Indicators of Basic Early Literacy Skills) ORF (Oral Reading Fluency) for predicting performance on the Florida Comprehensive Assessment Test (FCAT-SSS) and Stanford Achievement Test (SAT-10) reading comprehension measures. The usefulness of previously established ORF risk-level cutoffs [Good, R.H., Simmons, D.C., and Kame'enui, E.J. (2001). The importance and decision-making utility of a continuum of fluency-based indicators of foundational reading skills for third-grade high-stakes outcomes. Scientific Studies of Reading, 5, 257-288.] for third grade students were evaluated on calibration (n(S1)=16,539) and cross-validation (n(S2)=16,908) samples representative of Florida's Reading First population. The strongest correlations were the third (February/March) administration of ORF with both FCAT-SSS and SAT-10 (r(S)=.70-.71), when the three tests were administered concurrently. Recalibrated ORF risk-level cut scores derived from ROC (receiver-operating characteristic) curve analyses produced more accurate identification of true positives than previously established benchmarks. The recalibrated risk-level cut scores predict performance on the FCAT-SSS equally well for students from different socio-economic, language, and race/ethnicity categories.

  11. Reduced Set of Virulence Genes Allows High Accuracy Prediction of Bacterial Pathogenicity in Humans

    PubMed Central

    Iraola, Gregorio; Vazquez, Gustavo; Spangenberg, Lucía; Naya, Hugo

    2012-01-01

    Although there have been great advances in understanding bacterial pathogenesis, there is still a lack of integrative information about what makes a bacterium a human pathogen. The advent of high-throughput sequencing technologies has dramatically increased the amount of completed bacterial genomes, for both known human pathogenic and non-pathogenic strains; this information is now available to investigate genetic features that determine pathogenic phenotypes in bacteria. In this work we determined presence/absence patterns of different virulence-related genes among more than finished bacterial genomes from both human pathogenic and non-pathogenic strains, belonging to different taxonomic groups (i.e: Actinobacteria, Gammaproteobacteria, Firmicutes, etc.). An accuracy of 95% using a cross-fold validation scheme with in-fold feature selection is obtained when classifying human pathogens and non-pathogens. A reduced subset of highly informative genes () is presented and applied to an external validation set. The statistical model was implemented in the BacFier v1.0 software (freely available at ), that displays not only the prediction (pathogen/non-pathogen) and an associated probability for pathogenicity, but also the presence/absence vector for the analyzed genes, so it is possible to decipher the subset of virulence genes responsible for the classification on the analyzed genome. Furthermore, we discuss the biological relevance for bacterial pathogenesis of the core set of genes, corresponding to eight functional categories, all with evident and documented association with the phenotypes of interest. Also, we analyze which functional categories of virulence genes were more distinctive for pathogenicity in each taxonomic group, which seems to be a completely new kind of information and could lead to important evolutionary conclusions. PMID:22916122

  12. Persistency of Prediction Accuracy and Genetic Gain in Synthetic Populations Under Recurrent Genomic Selection.

    PubMed

    Müller, Dominik; Schopp, Pascal; Melchinger, Albrecht E

    2017-03-10

    Recurrent selection (RS) has been used in plant breeding to successively improve synthetic and other multiparental populations. Synthetics are generated from a limited number of parents [Formula: see text] but little is known about how [Formula: see text] affects genomic selection (GS) in RS, especially the persistency of prediction accuracy ([Formula: see text]) and genetic gain. Synthetics were simulated by intermating [Formula: see text]= 2-32 parent lines from an ancestral population with short- or long-range linkage disequilibrium ([Formula: see text]) and subjected to multiple cycles of GS. We determined [Formula: see text] and genetic gain across 30 cycles for different training set (TS) sizes, marker densities, and generations of recombination before model training. Contributions to [Formula: see text] and genetic gain from pedigree relationships, as well as from cosegregation and [Formula: see text] between QTL and markers, were analyzed via four scenarios differing in (i) the relatedness between TS and selection candidates and (ii) whether selection was based on markers or pedigree records. Persistency of [Formula: see text] was high for small [Formula: see text] where predominantly cosegregation contributed to [Formula: see text], but also for large [Formula: see text] where [Formula: see text] replaced cosegregation as the dominant information source. Together with increasing genetic variance, this compensation resulted in relatively constant long- and short-term genetic gain for increasing [Formula: see text] > 4, given long-range LDA in the ancestral population. Although our scenarios suggest that information from pedigree relationships contributed to [Formula: see text] for only very few generations in GS, we expect a longer contribution than in pedigree BLUP, because capturing Mendelian sampling by markers reduces selective pressure on pedigree relationships. Larger TS size ([Formula: see text]) and higher marker density improved persistency of

  13. Persistency of Prediction Accuracy and Genetic Gain in Synthetic Populations Under Recurrent Genomic Selection

    PubMed Central

    Müller, Dominik; Schopp, Pascal; Melchinger, Albrecht E.

    2017-01-01

    Recurrent selection (RS) has been used in plant breeding to successively improve synthetic and other multiparental populations. Synthetics are generated from a limited number of parents (Np), but little is known about how Np affects genomic selection (GS) in RS, especially the persistency of prediction accuracy (rg,g^) and genetic gain. Synthetics were simulated by intermating Np= 2–32 parent lines from an ancestral population with short- or long-range linkage disequilibrium (LDA) and subjected to multiple cycles of GS. We determined rg,g^ and genetic gain across 30 cycles for different training set (TS) sizes, marker densities, and generations of recombination before model training. Contributions to rg,g^ and genetic gain from pedigree relationships, as well as from cosegregation and LDA between QTL and markers, were analyzed via four scenarios differing in (i) the relatedness between TS and selection candidates and (ii) whether selection was based on markers or pedigree records. Persistency of rg,g^ was high for small Np, where predominantly cosegregation contributed to rg,g^, but also for large Np, where LDA replaced cosegregation as the dominant information source. Together with increasing genetic variance, this compensation resulted in relatively constant long- and short-term genetic gain for increasing Np > 4, given long-range LDA in the ancestral population. Although our scenarios suggest that information from pedigree relationships contributed to rg,g^ for only very few generations in GS, we expect a longer contribution than in pedigree BLUP, because capturing Mendelian sampling by markers reduces selective pressure on pedigree relationships. Larger TS size (NTS) and higher marker density improved persistency of rg,g^ and hence genetic gain, but additional recombinations could not increase genetic gain. PMID:28064189

  14. Measuring the accuracy of particle position and force in optical tweezers using high-speed video microscopy.

    PubMed

    Gibson, Graham M; Leach, Jonathan; Keen, Stephen; Wright, Amanda J; Padgett, Miles J

    2008-09-15

    We assess the performance of a CMOS camera for the measurement of particle position within optical tweezers and the associated autocorrelation function and power spectrum. Measurement of the displacement of the particle from the trap center can also be related to the applied force. By considering the Allan variance of these measurements, we show that such cameras are capable of reaching the thermal limits of nanometer and femtonewton accuracies, and hence are suitable for many of the applications that traditionally use quadrant photodiodes. As an example of a multi-particle measurement we show the hydrodynamic coupling between two particles.

  15. Time to positivity and detection of growth in anaerobic blood culture vials predict the presence of Candida glabrata in candidemia: a two-center European cohort study.

    PubMed

    Cobos-Trigueros, Nazaret; Kaasch, Achim J; Soriano, Alex; Torres, Jorge-Luis; Vergara, Andrea; Morata, Laura; Zboromyrska, Yuliya; De La Calle, Cristina; Alejo, Izaskun; Hernández, Cristina; Cardozo, Celia; Marco, Franscesc; Del Río, Ana; Almela, Manel; Mensa, Josep; Martínez, José Antonio

    2014-08-01

    This study shows the accuracy of exclusive or earlier growth in anaerobic vials to predict Candida glabrata in a large series of candidemic patients from two European hospitals using the Bactec 9240 system. Alternatively, C. glabrata can be predicted by a time to positivity cutoff value, which should be determined for each setting.

  16. A simple and fast approach to prediction of protein secondary structure from multiply aligned sequences with accuracy above 70%.

    PubMed Central

    Mehta, P. K.; Heringa, J.; Argos, P.

    1995-01-01

    To improve secondary structure predictions in protein sequences, the information residing in multiple sequence alignments of substituted but structurally related proteins is exploited. A database comprised of 70 protein families and a total of 2,500 sequences, some of which were aligned by tertiary structural superpositions, was used to calculate residue exchange weight matrices within alpha-helical, beta-strand, and coil substructures, respectively. Secondary structure predictions were made based on the observed residue substitutions in local regions of the multiple alignments and the largest possible associated exchange weights in each of the three matrix types. Comparison of the observed and predicted secondary structure on a per-residue basis yielded a mean accuracy of 72.2%. Individual alpha-helix, beta-strand, and coil states were respectively predicted at 66.7, and 75.8% correctness, representing a well-balanced three-state prediction. The accuracy level, verified by cross-validation through jack-knife tests on all protein families, dropped, on average, to only 70.9%, indicating the rigor of the prediction procedure. On the basis of robustness, conceptual clarity, accuracy, and executable efficiency, the method has considerable advantage, especially with its sole reliance on amino acid substitutions within structurally related proteins. PMID:8580842

  17. Classification Accuracy of Oral Reading Fluency and Maze in Predicting Performance on Large-Scale Reading Assessments

    ERIC Educational Resources Information Center

    Decker, Dawn M.; Hixson, Michael D.; Shaw, Amber; Johnson, Gloria

    2014-01-01

    The purpose of this study was to examine whether using a multiple-measure framework yielded better classification accuracy than oral reading fluency (ORF) or maze alone in predicting pass/fail rates for middle-school students on a large-scale reading assessment. Participants were 178 students in Grades 7 and 8 from a Midwestern school district.…

  18. The Accuracy of Recidivism Risk Assessments for Sexual Offenders: A Meta-Analysis of 118 Prediction Studies

    ERIC Educational Resources Information Center

    Hanson, R. Karl; Morton-Bourgon, Kelly E.

    2009-01-01

    This review compared the accuracy of various approaches to the prediction of recidivism among sexual offenders. On the basis of a meta-analysis of 536 findings drawn from 118 distinct samples (45,398 sexual offenders, 16 countries), empirically derived actuarial measures were more accurate than unstructured professional judgment for all outcomes…

  19. Ultrasound Indoor Positioning System Based on a Low-Power Wireless Sensor Network Providing Sub-Centimeter Accuracy

    PubMed Central

    Medina, Carlos; Segura, José Carlos; De la Torre, Ángel

    2013-01-01

    This paper describes the TELIAMADE system, a new indoor positioning system based on time-of-flight (TOF) of ultrasonic signal to estimate the distance between a receiver node and a transmitter node. TELIAMADE system consists of a set of wireless nodes equipped with a radio module for communication and a module for the transmission and reception of ultrasound. The access to the ultrasonic channel is managed by applying a synchronization algorithm based on a time-division multiplexing (TDMA) scheme. The ultrasonic signal is transmitted using a carrier frequency of 40 kHz and the TOF measurement is estimated by applying a quadrature detector to the signal obtained at the A/D converter output. Low sampling frequencies of 17.78 kHz or even 12.31 kHz are possible using quadrature sampling in order to optimize memory requirements and to reduce the computational cost in signal processing. The distance is calculated from the TOF taking into account the speed of sound. An excellent accuracy in the estimation of the TOF is achieved using parabolic interpolation to detect of maximum of the signal envelope at the matched filter output. The signal phase information is also used for enhancing the TOF measurement accuracy. Experimental results show a root mean square error (rmse) less than 2 mm and a standard deviation less than 0.3 mm for pseudorange measurements in the range of distances between 2 and 6 m. The system location accuracy is also evaluated by applying multilateration. A sub-centimeter location accuracy is achieved with an average rmse of 9.6 mm. PMID:23486218

  20. Ultrasound indoor positioning system based on a low-power wireless sensor network providing sub-centimeter accuracy.

    PubMed

    Medina, Carlos; Segura, José Carlos; De la Torre, Ángel

    2013-03-13

    This paper describes the TELIAMADE system, a new indoor positioning system based on time-of-flight (TOF) of ultrasonic signal to estimate the distance between a receiver node and a transmitter node. TELIAMADE system consists of a set of wireless nodes equipped with a radio module for communication and a module for the transmission and reception of ultrasound. The access to the ultrasonic channel is managed by applying a synchronization algorithm based on a time-division multiplexing (TDMA) scheme. The ultrasonic signal is transmitted using a carrier frequency of 40 kHz and the TOF measurement is estimated by applying a quadrature detector to the signal obtained at the A/D converter output. Low sampling frequencies of 17.78 kHz or even 12.31 kHz are possible using quadrature sampling in order to optimize memory requirements and to reduce the computational cost in signal processing. The distance is calculated from the TOF taking into account the speed of sound. An excellent accuracy in the estimation of the TOF is achieved using parabolic interpolation to detect of maximum of the signal envelope at the matched filter output. The signal phase information is also used for enhancing the TOF measurement accuracy. Experimental results show a root mean square error (rmse) less than 2 mm and a standard deviation less than 0.3 mm for pseudorange measurements in the range of distances between 2 and 6 m. The system location accuracy is also evaluated by applying multilateration. A sub-centimeter location accuracy is achieved with an average rmse of 9.6 mm.

  1. Development and application of a statistical methodology to evaluate the predictive accuracy of building energy baseline models

    SciTech Connect

    Granderson, Jessica; Price, Phillip N.

    2014-03-01

    This paper documents the development and application of a general statistical methodology to assess the accuracy of baseline energy models, focusing on its application to Measurement and Verification (M&V) of whole-­building energy savings. The methodology complements the principles addressed in resources such as ASHRAE Guideline 14 and the International Performance Measurement and Verification Protocol. It requires fitting a baseline model to data from a ``training period’’ and using the model to predict total electricity consumption during a subsequent ``prediction period.’’ We illustrate the methodology by evaluating five baseline models using data from 29 buildings. The training period and prediction period were varied, and model predictions of daily, weekly, and monthly energy consumption were compared to meter data to determine model accuracy. Several metrics were used to characterize the accuracy of the predictions, and in some cases the best-­performing model as judged by one metric was not the best performer when judged by another metric.

  2. Multinational assessment of accuracy of equations for predicting risk of kidney failure: a meta-analysis

    PubMed Central

    Tangri, Navdeep; Grams, Morgan E.; Levey, Andrew S.; Coresh, Josef; Appel, Lawrence; Astor, Brad C.; Chodick, Gabriel; Collins, Allan J.; Djurdjev, Ognjenka; Elley, C. Raina; Evans, Marie; Garg, Amit X.; Hallan, Stein I.; Inker, Lesley; Ito, Sadayoshi; Jee, Sun Ha; Kovesdy, Csaba P.; Kronenberg, Florian; Lambers Heerspink, Hiddo J.; Marks, Angharad; Nadkarni, Girish N.; Navaneethan, Sankar D.; Nelson, Robert G.; Titze, Stephanie; Sarnak, Mark J.; Stengel, Benedicte; Woodward, Mark; Iseki, Kunitoshi

    2016-01-01

    Importance Identifying patients at risk of chronic kidney disease (CKD) progression may facilitate more optimal nephrology care. Kidney failure risk equations (KFREs) were previously developed and validated in two Canadian cohorts. Validation in other regions and in CKD populations not under the care of a nephrologist is needed. Objective To evaluate the accuracy of the KFREs across different geographic regions and patient populations through individual-participant data meta-analysis. Data Sources Thirty-one cohorts, including 721,357 participants with CKD Stages 3–5 in over 30 countries spanning 4 continents, were studied. These cohorts collected data from 1982 through 2014. Study Selection Cohorts participating in the CKD Prognosis Consortium with data on end-stage renal disease. Data Extraction and Synthesis Data were obtained and statistical analyses were performed between July 2012 and June 2015. Using the risk factors from the original KFREs, cohort-specific hazard ratios were estimated, and combined in meta-analysis to form new “pooled” KFREs. Original and pooled equation performance was compared, and the need for regional calibration factors was assessed. Main Outcome and Measure Kidney failure (treatment by dialysis or kidney transplantation). Results During a median follow-up of 4 years, 23,829 cases of kidney failure were observed. The original KFREs achieved excellent discrimination (ability to differentiate those who developed kidney failure from those who did not) across all cohorts (overall C statistic, 0.90 (95% CI 0.89–0.92) at 2 years and 0.88 (95% CI 0.86–0.90) at 5 years); discrimination in subgroups by age, race, and diabetes status was similar. There was no improvement with the pooled equations. Calibration (the difference between observed and predicted risk) was adequate in North American cohorts, but the original KFREs overestimated risk in some non-North American cohorts. Addition of a calibration factor that lowered the baseline

  3. Accuracy of Two Motor Assessments during the First Year of Life in Preterm Infants for Predicting Motor Outcome at Preschool Age

    PubMed Central

    Spittle, Alicia J.; Lee, Katherine J.; Spencer-Smith, Megan; Lorefice, Lucy E.; Anderson, Peter J.; Doyle, Lex W.

    2015-01-01

    Aim The primary aim of this study was to investigate the accuracy of the Alberta Infant Motor Scale (AIMS) and Neuro-Sensory Motor Developmental Assessment (NSMDA) over the first year of life for predicting motor impairment at 4 years in preterm children. The secondary aims were to assess the predictive value of serial assessments over the first year and when using a combination of these two assessment tools in follow-up. Method Children born <30 weeks’ gestation were prospectively recruited and assessed at 4, 8 and 12 months’ corrected age using the AIMS and NSMDA. At 4 years’ corrected age children were assessed for cerebral palsy (CP) and motor impairment using the Movement Assessment Battery for Children 2nd-edition (MABC-2). We calculated accuracy of the AIMS and NSMDA for predicting CP and MABC-2 scores ≤15th (at-risk of motor difficulty) and ≤5th centile (significant motor difficulty) for each test (AIMS and NSMDA) at 4, 8 and 12 months, for delay on one, two or all three of the time points over the first year, and finally for delay on both tests at each time point. Results Accuracy for predicting motor impairment was good for each test at each age, although false positives were common. Motor impairment on the MABC-2 (scores ≤5th and ≤15th) was most accurately predicted by the AIMS at 4 months, whereas CP was most accurately predicted by the NSMDA at 12 months. In regards to serial assessments, the likelihood ratio for motor impairment increased with the number of delayed assessments. When combining both the NSMDA and AIMS the best accuracy was achieved at 4 months, although results were similar at 8 and 12 months. Interpretation Motor development during the first year of life in preterm infants assessed with the AIMS and NSMDA is predictive of later motor impairment at preschool age. However, false positives are common and therefore it is beneficial to follow-up children at high risk of motor impairment at more than one time point, or to use a

  4. Prediction accuracy in estimating joint angle trajectories using a video posture coding method for sagittal lifting tasks.

    PubMed

    Chang, Chien-Chi; McGorry, Raymond W; Lin, Jia-Hua; Xu, Xu; Hsiang, Simon M

    2010-08-01

    This study investigated prediction accuracy of a video posture coding method for lifting joint trajectory estimation. From three filming angles, the coder selected four key snapshots, identified joint angles and then a prediction program estimated the joint trajectories over the course of a lift. Results revealed a limited range of differences of joint angles (elbow, shoulder, hip, knee, ankle) between the manual coding method and the electromagnetic motion tracking system approach. Lifting range significantly affected estimate accuracy for all joints and camcorder filming angle had a significant effect on all joints but the hip. Joint trajectory predictions were more accurate for knuckle-to-shoulder lifts than for floor-to-shoulder or floor-to-knuckle lifts with average root mean square errors (RMSE) of 8.65 degrees , 11.15 degrees and 11.93 degrees , respectively. Accuracy was also greater for the filming angles orthogonal to the participant's sagittal plane (RMSE = 9.97 degrees ) as compared to filming angles of 45 degrees (RMSE = 11.01 degrees ) or 135 degrees (10.71 degrees ). The effects of lifting speed and loading conditions were minimal. To further increase prediction accuracy, improved prediction algorithms and/or better posture matching methods should be investigated. STATEMENT OF RELEVANCE: Observation and classification of postures are common steps in risk assessment of manual materials handling tasks. The ability to accurately predict lifting patterns through video coding can provide ergonomists with greater resolution in characterising or assessing the lifting tasks than evaluation based solely on sampling with a single lifting posture event.

  5. High-Accuracy Self-Calibration for Smart, Optical Orbiting Payloads Integrated with Attitude and Position Determination

    PubMed Central

    Li, Jin; Xing, Fei; Chu, Daping; Liu, Zilong

    2016-01-01

    A high-accuracy space smart payload integrated with attitude and position (SSPIAP) is a new type of optical remote sensor that can autonomously complete image positioning. Inner orientation parameters (IOPs) are a prerequisite for image position determination of an SSPIAP. The calibration of IOPs significantly influences the precision of image position determination of SSPIAPs. IOPs can be precisely measured and calibrated in a laboratory. However, they may drift to a significant degree because of vibrations during complicated launches and on-orbit functioning. Therefore, laboratory calibration methods are not suitable for on-orbit functioning. We propose an on-orbit self-calibration method for SSPIAPs. Our method is based on an auto-collimating dichroic filter combined with a micro-electro-mechanical system (MEMS) point-source focal plane. A MEMS procedure is used to manufacture a light transceiver focal plane, which integrates with point light sources and a complementary metal oxide semiconductor (CMOS) sensor. A dichroic filter is used to fabricate an auto-collimation light reflection element. The dichroic filter and the MEMS point light sources focal plane are integrated into an SSPIAP so it can perform integrated self-calibration. Experiments show that our method can achieve micrometer-level precision, which is good enough to complete real-time calibration without temporal or spatial limitations. PMID:27472339

  6. Predicting Likelihood of Having Four or More Positive Nodes in Patient With Sentinel Lymph Node-Positive Breast Cancer: A Nomogram Validation Study

    SciTech Connect

    Unal, Bulent; Gur, Akif Serhat; Beriwal, Sushil; Tang Gong; Johnson, Ronald; Ahrendt, Gretchen; Bonaventura, Marguerite; Soran, Atilla

    2009-11-15

    Purpose: Katz suggested a nomogram for predicting having four or more positive nodes in sentinel lymph node (SLN)-positive breast cancer patients. The findings from this formula might influence adjuvant radiotherapy decisions. Our goal was to validate the accuracy of the Katz nomogram. Methods and Materials: We reviewed the records of 309 patients with breast cancer who had undergone completion axillary lymph node dissection. The factors associated with the likelihood of having four or more positive axillary nodes were evaluated in patients with one to three positive SLNs. The nomogram developed by Katz was applied to our data set. The area under the curve of the corresponding receiver operating characteristics curve was calculated for the nomogram. Results: Of the 309 patients, 80 (25.9%) had four or more positive axillary lymph nodes. On multivariate analysis, the number of positive SLNs (p < .0001), overall metastasis size (p = .019), primary tumor size (p = .0001), and extracapsular extension (p = .01) were significant factors predicting for four or more positive nodes. For patients with <5% probability, 90.3% had fewer than four positive nodes and 9.7% had four or more positive nodes. The negative predictive value was 91.7%, and sensitivity was 80%. The nomogram was accurate and discriminating (area under the curve, .801). Conclusion: The probability of four or more involved nodes is significantly greater in patients who have an increased number of positive SLNs, increased overall metastasis size, increased tumor size, and extracapsular extension. The Katz nomogram was validated in our patients. This nomogram will be helpful to clinicians making adjuvant treatment recommendations to their patients.

  7. Accuracy of genomic prediction in switchgrass (Panicum virgatum L.) improved by accounting for linkage disequilibrium

    SciTech Connect

    Ramstein, Guillaume P.; Evans, Joseph; Kaeppler, Shawn M.; Mitchell, Robert B.; Vogel, Kenneth P.; Buell, C. Robin; Casler, Michael D.

    2016-02-11

    Switchgrass is a relatively high-yielding and environmentally sustainable biomass crop, but further genetic gains in biomass yield must be achieved to make it an economically viable bioenergy feedstock. Genomic selection (GS) is an attractive technology to generate rapid genetic gains in switchgrass, and meet the goals of a substantial displacement of petroleum use with biofuels in the near future. In this study, we empirically assessed prediction procedures for genomic selection in two different populations, consisting of 137 and 110 half-sib families of switchgrass, tested in two locations in the United States for three agronomic traits: dry matter yield, plant height, and heading date. Marker data were produced for the families’ parents by exome capture sequencing, generating up to 141,030 polymorphic markers with available genomic-location and annotation information. We evaluated prediction procedures that varied not only by learning schemes and prediction models, but also by the way the data were preprocessed to account for redundancy in marker information. More complex genomic prediction procedures were generally not significantly more accurate than the simplest procedure, likely due to limited population sizes. Nevertheless, a highly significant gain in prediction accuracy was achieved by transforming the marker data through a marker correlation matrix. Our results suggest that marker-data transformations and, more generally, the account of linkage disequilibrium among markers, offer valuable opportunities for improving prediction procedures in GS. Furthermore, some of the achieved prediction accuracies should motivate implementation of GS in switchgrass breeding programs.

  8. Age-Related Differences in the Accuracy of Web Query-Based Predictions of Influenza-Like Illness

    PubMed Central

    Domnich, Alexander; Panatto, Donatella; Signori, Alessio; Lai, Piero Luigi; Gasparini, Roberto; Amicizia, Daniela

    2015-01-01

    Background Web queries are now widely used for modeling, nowcasting and forecasting influenza-like illness (ILI). However, given that ILI attack rates vary significantly across ages, in terms of both magnitude and timing, little is known about whether the association between ILI morbidity and ILI-related queries is comparable across different age-groups. The present study aimed to investigate features of the association between ILI morbidity and ILI-related query volume from the perspective of age. Methods Since Google Flu Trends is unavailable in Italy, Google Trends was used to identify entry terms that correlated highly with official ILI surveillance data. All-age and age-class-specific modeling was performed by means of linear models with generalized least-square estimation. Hold-out validation was used to quantify prediction accuracy. For purposes of comparison, predictions generated by exponential smoothing were computed. Results Five search terms showed high correlation coefficients of > .6. In comparison with exponential smoothing, the all-age query-based model correctly predicted the peak time and yielded a higher correlation coefficient with observed ILI morbidity (.978 vs. .929). However, query-based prediction of ILI morbidity was associated with a greater error. Age-class-specific query-based models varied significantly in terms of prediction accuracy. In the 0–4 and 25–44-year age-groups, these did well and outperformed exponential smoothing predictions; in the 15–24 and ≥ 65-year age-classes, however, the query-based models were inaccurate and highly overestimated peak height. In all but one age-class, peak timing predicted by the query-based models coincided with observed timing. Conclusions The accuracy of web query-based models in predicting ILI morbidity rates could differ among ages. Greater age-specific detail may be useful in flu query-based studies in order to account for age-specific features of the epidemiology of ILI. PMID:26011418

  9. Evaluation of MLC leaf positioning accuracy for static and dynamic IMRT treatments using DAVID in vivo dosimetric system.

    PubMed

    Karagoz, Gulay; Zorlu, Faruk; Yeginer, Mete; Yildiz, Demet; Ozyigit, Gokhan

    2016-03-08

    Accuracy and precision of leaf positioning in multileaf collimators (MLCs) are significant factors for the accuracy of IMRT treatments. This study aimed to inves-tigate the accuracy and repeatability of the MLC leaf positioning via the DAVID invivo dosimetric system for dynamic and static MLC systems. The DAVID system was designed as multiwire transmission ionization chamber which is placed in accessory holder of linear accelerators. Each wire of DAVID system corresponds to a MLC leaf-pair to verify the leaf positioning accuracy during IMRT treatment and QA. In this study, verifications of IMRT plans of five head and neck (H&N) and five prostate patients treated in a Varian DHX linear accelerator with 80-leaf MLC were performed using DAVID system. Before DAVID-based dosimetry, Electronics Portal Imaging Device (EPID) and PTW 2D ARRAY dosimetry system were used for 2D verification of each plan. The measurements taken by DAVID system in the first day of the treatments were used as reference for the following measurements taken over the next four weeks. The deviations in leaf positioning were evaluated by "Total Deviation (TD)" parameter calculated by DAVID software. The delivered IMRT plans were originally prepared using dynamic MLC method. The same plans were subsequently calculated based on static MLC method with three different intensity levels of five (IL5), 10 (IL10) and 20 (IL20) in order to compare the performances of MLC leaf positioning repeatability for dynamic and static IMRT plans. The leaf positioning accuracy is also evaluated by analyzing DynaLog files based on error histograms and root mean square (RMS) errors of leaf pairs' positions. Moreover, a correlation analysis between simultaneously taken DAVID and EPID measurements and DynaLog file recordings was subsequently performed. In the analysis of DAVID outputs, the overall deviations of dynamic MLC-based IMRT calculated from the deviations of the four weeks were found as 0.55% ± 0.57% and 1.48% ± 0

  10. Evaluation of MLC leaf positioning accuracy for static and dynamic IMRT treatments using DAVID in vivo dosimetric system.

    PubMed

    Karagoz, Gulay; Zorlu, Faruk; Yeginer, Mete; Yildiz, Demet; Ozyigit, Gokhan

    2016-03-01

    Accuracy and precision of leaf positioning in multileaf collimators (MLCs) are significant factors for the accuracy of IMRT treatments. This study aimed to investigate the accuracy and repeatability of the MLC leaf positioning via the DAVID in vivo dosimetric system for dynamic and static MLC systems. The DAVID system was designed as multiwire transmission ionization chamber which is placed in accessory holder of linear accelerators. Each wire of DAVID system corresponds to a MLC leaf-pair to verify the leaf positioning accuracy during IMRT treatment and QA. In this study, verifications of IMRT plans of five head and neck (H&N) and five prostate patients treated in a Varian DHX linear accelerator with 80-leaf MLC were performed using DAVID system. Before DAVID-based dosimetry, Electronics Portal Imaging Device (EPID) and PTW 2D ARRAY dosimetry system were used for 2D verification of each plan. The measurements taken by DAVID system in the first day of the treatments were used as reference for the following measurements taken over the next four weeks. The deviations in leaf positioning were evaluated by "Total Deviation (TD)" parameter calculated by DAVID software. The delivered IMRT plans were originally prepared using dynamic MLC method. The same plans were subsequently calculated based on static MLC method with three different intensity levels of five (IL5), 10 (IL10) and 20 (IL20) in order to compare the performances of MLC leaf positioning repeatability for dynamic and static IMRT plans. The leaf positioning accuracy is also evaluated by analyzing DynaLog files based on error histograms and root mean square (RMS) errors of leaf pairs' positions. Moreover, a correlation analysis between simultaneously taken DAVID and EPID measurements and DynaLog file recordings was subsequently performed. In the analysis of DAVID outputs, the overall deviations of dynamic MLC-based IMRT calculated from the deviations of the four weeks were found as 0.55%±0.57% and 1.48%±0

  11. Assessing the accuracy of software predictions of mammalian and microbial metabolites

    EPA Science Inventory

    New chemical development and hazard assessments benefit from accurate predictions of mammalian and microbial metabolites. Fourteen biotransformation libraries encoded in eight software packages that predict metabolite structures were assessed for their sensitivity (proportion of ...

  12. Geopositioning accuracy prediction results for registration of imaging and nonimaging sensors using moving objects

    NASA Astrophysics Data System (ADS)

    Taylor, Charles R.; Dolloff, John T.; Lofy, Brian A.; Luker, Steve A.

    2003-08-01

    BAE SYSTEMS is developing a "4D Registration" capability for DARPA's Dynamic Tactical Targeting program. This will further advance our automatic image registration capability to use moving objects for image registration, and extend our current capability to include the registration of non-imaging sensors. Moving objects produce signals that are identifiable across multiple sensors such as radar moving target indicators, unattended ground sensors, and imaging sensors. Correspondences of those signals across sensor types make it possible to improve the support data accuracy for each of the sensors involved in the correspondence. The amount of accuracy improvement possible, and the effects of the accuracy improvement on geopositioning with the sensors, is a complex problem. The main factors that contribute to the complexity are the sensor-to-target geometry, the a priori sensor support data accuracy, sensor measurement accuracy, the distribution of identified objects in ground space, and the motion and motion uncertainty of the identified objects. As part of the 4D Registration effort, BAE SYSTEMS is conducting a sensitivity study to investigate the complexities and benefits of multisensor registration with moving objects. The results of the study will be summarized.

  13. Estimation of accuracies and expected genetic change from selection for selection indexes that use multiple-trait predictions of breeding values.

    PubMed

    Barwick, S A; Tier, B; Swan, A A; Henzell, A L

    2013-10-01

    Procedures are described for estimating selection index accuracies for individual animals and expected genetic change from selection for the general case where indexes of EBVs predict an aggregate breeding objective of traits that may or may not have been measured. Index accuracies for the breeding objective are shown to take an important general form, being able to be expressed as the product of the accuracy of the index function of true breeding values and the accuracy with which that function predicts the breeding objective. When the accuracies of the individual EBVs of the index are known, prediction error variances (PEVs) and covariances (PECs) for the EBVs within animal are able to be well approximated, and index accuracies and expected genetic change from selection estimated with high accuracy. The procedures are suited to routine use in estimating index accuracies in genetic evaluation, and for providing important information, without additional modelling, on the directions in which a population will move under selection.

  14. Effect of homogenizer performance on accuracy and repeatability of mid-infrared predicted values for major milk components.

    PubMed

    Di Marzo, Larissa; Barbano, David M

    2016-12-01

    Our objective was to determine the effect of mid-infrared (MIR) homogenizer efficiency on accuracy and repeatability of Fourier transform MIR predicted fat, true protein, and anhydrous lactose determination given by traditional filter and partial least squares (PLS) prediction models. Five homogenizers with different homogenization performance based on laser light-scattering particle size analysis were used. Repeatability and accuracy were determined by conducting 17 sequential readings on milk homogenized externally to the instrument (i.e., control) and unhomogenized milk. Milk component predictions on externally homogenized milks were affected by variation in homogenizer performance, but the magnitude of effect were small (i.e., <0.025%) when milks were pumped through both efficient and inefficient homogenizers within a MIR milk analyzer. Variation in the in-line MIR homogenizer performance on unhomogenized milks had a much larger effect on accuracy of component testing than on repeatability. The increase of particle size distribution [d(0.9)] from 1.35 to 3.03μm (i.e., fat globule diameter above which 10% of the volume of fat is contained) due to poor homogenization affected fat tests the most; traditional filter based fat B (carbon hydrogen stretch; -0.165%), traditional filter-based fat A (carbonyl stretch; -0.074%), and fat PLS (-0.078%) at a d(0.9) of 3.03μm. Variation in homogenization efficiency also affected traditional filter-based true protein test (+0.012%), true protein PLS prediction (-0.107%), and traditional filter-based anhydrous lactose test (+0.027%) at a d(0.9) of 3.03μm. Effects of variation in homogenization on anhydrous lactose PLS predictions were small. The accuracy of both traditional filter models and PLS models were influenced by poor homogenization. The value of 1.7µm for a d(0.9) used by the USDA Federal Milk Market laboratories as a criterion to make the decision to replace the homogenizer in a MIR milk analyzer appears to be a

  15. Challenging the 10-year rule: The accuracy of patient life expectancy predictions by physicians in relation to prostate cancer management

    PubMed Central

    Leung, Kevin M.Y.B.; Hopman, Wilma M; Kawakami, Jun

    2012-01-01

    Introduction: We assess physicians’ ability to accurately predict life expectancies. In prostate cancer this prediction is especially important as it affects screening decisions. No previous studies have examined accuracy in the context of real cases and concrete end points. Methods: Seven clinical scenarios were summarized from charts of deceased patients. We recruited 100 medical professionals to review these scenarios and estimate each patient’s life expectancy. Responses were analyzed with respect to the patients’ actual survival end points, then stratified based on the demographic information provided. Results: Respondent factors, such as sex, level of training, location of work or specialty, made no significant difference on prediction accuracy. Furthermore, respondents were typically pessimistic in their estimations with a negative linear trend between estimated life expectancy and actual survival. Overall, respondents were within 1 year of actual life expectancy only 15.9% of the time; on average, respondents were 67.4% inaccurate in relation to actual survival. If framed in terms of correctly identifying which patients would live more than or less than 10 years (dichotomous accuracy), physicians were correct 68.3% of the time. Conclusions: Physicians do poorly at predicting life expectancy and tend to underestimate how long patients have left to live. This overall inaccuracy raises the question of whether physicians should refine screening and treatment criteria, find a better proxy or dispose of the criteria altogether. PMID:23093629

  16. Performance characterization of precision micro robot using a machine vision system over the Internet for guaranteed positioning accuracy

    NASA Astrophysics Data System (ADS)

    Kwon, Yongjin; Chiou, Richard; Rauniar, Shreepud; Sosa, Horacio

    2005-11-01

    There is a missing link between a virtual development environment (e.g., a CAD/CAM driven offline robotic programming) and production requirements of the actual robotic workcell. Simulated robot path planning and generation of pick-and-place coordinate points will not exactly coincide with the robot performance due to lack of consideration in variations in individual robot repeatability and thermal expansion of robot linkages. This is especially important when robots are controlled and programmed remotely (e.g., through Internet or Ethernet) since remote users have no physical contact with robotic systems. Using the current technology in Internet-based manufacturing that is limited to a web camera for live image transfer has been a significant challenge for the robot task performance. Consequently, the calibration and accuracy quantification of robot critical to precision assembly have to be performed on-site and the verification of robot positioning accuracy cannot be ascertained remotely. In worst case, the remote users have to assume the robot performance envelope provided by the manufacturers, which may causes a potentially serious hazard for system crash and damage to the parts and robot arms. Currently, there is no reliable methodology for remotely calibrating the robot performance. The objective of this research is, therefore, to advance the current state-of-the-art in Internet-based control and monitoring technology, with a specific aim in the accuracy calibration of micro precision robotic system for the development of a novel methodology utilizing Ethernet-based smart image sensors and other advanced precision sensory control network.

  17. Optimization of the Coverage and Accuracy of an Indoor Positioning System with a Variable Number of Sensors

    PubMed Central

    Domingo-Perez, Francisco; Lazaro-Galilea, Jose Luis; Bravo, Ignacio; Gardel, Alfredo; Rodriguez, David

    2016-01-01

    This paper focuses on optimal sensor deployment for indoor localization with a multi-objective evolutionary algorithm. Our goal is to obtain an algorithm to deploy sensors taking the number of sensors, accuracy and coverage into account. Contrary to most works in the literature, we consider the presence of obstacles in the region of interest (ROI) that can cause occlusions between the target and some sensors. In addition, we aim to obtain all of the Pareto optimal solutions regarding the number of sensors, coverage and accuracy. To deal with a variable number of sensors, we add speciation and structural mutations to the well-known non-dominated sorting genetic algorithm (NSGA-II). Speciation allows one to keep the evolution of sensor sets under control and to apply genetic operators to them so that they compete with other sets of the same size. We show some case studies of the sensor placement of an infrared range-difference indoor positioning system with a fairly complex model of the error of the measurements. The results obtained by our algorithm are compared to sensor placement patterns obtained with random deployment to highlight the relevance of using such a deployment algorithm. PMID:27338414

  18. Pitfalls at the root of facial assessment on photographs: a quantitative study of accuracy in positioning facial landmarks.

    PubMed

    Cummaudo, M; Guerzoni, M; Marasciuolo, L; Gibelli, D; Cigada, A; Obertovà, Z; Ratnayake, M; Poppa, P; Gabriel, P; Ritz-Timme, S; Cattaneo, C

    2013-05-01

    In the last years, facial analysis has gained great interest also for forensic anthropology. The application of facial landmarks may bring about relevant advantages for the analysis of 2D images by measuring distances and extracting quantitative indices. However, this is a complex task which depends upon the variability in positioning facial landmarks. In addition, literature provides only general indications concerning the reliability in positioning facial landmarks on photographic material, and no study is available concerning the specific errors which may be encountered in such an operation. The aim of this study is to analyze the inter- and intra-observer error in defining facial landmarks on photographs by using a software specifically developed for this purpose. Twenty-four operators were requested to define 22 facial landmarks on frontal view photographs and 11 on lateral view images; in addition, three operators repeated the procedure on the same photographs 20 times (at distance of 24 h). In the frontal view, the landmarks with less dispersion were the pupil, cheilion, endocanthion, and stomion (sto), and the landmarks with the highest dispersion were gonion, zygion, frontotemporale, tragion, and selion (se). In the lateral view, the landmarks with the least dispersion were se, pronasale, subnasale, and sto, whereas landmarks with the highest dispersion were gnathion, pogonion, and tragion. Results confirm that few anatomical points can be defined with the highest accuracy and show the importance of the preliminary investigation of reliability in positioning facial landmarks.

  19. Positioning System Accuracy Assessment for the Runway Incursion Prevention System Flight Test at the Dallas/Ft. Worth International Airport

    NASA Technical Reports Server (NTRS)

    Quach, Cuong C.

    2004-01-01

    NASA/Langley Research Center collaborated with the Federal Aviation Administration (FAA) to test a Runway Incursion Prevention System (RIPS) at the Dallas Fort Worth International Airport (DFW) in October 2000. The RIPS combines airborne and ground sensor data with various cockpit displays to improve pilots' awareness of traffic conditions on the airport surface. The systems tested at DFW involved surface radar and data systems that gather and send surface traffic information to a research aircraft outfitted with the RIPS software, cockpit displays, and data link transceivers. The data sent to the airborne systems contained identification and GPS location of traffic. This information was compared with the own-ship location from airborne GPS receivers to generate incursion alerts. A total of 93 test tracks were flown while operating RIPS. This report compares the accuracy of the airborne GPS systems that gave the own-ship position of the research aircraft for the 93 test tracks.

  20. Combining cow and bull reference populations to increase accuracy of genomic prediction and genome-wide association studies.

    PubMed

    Calus, M P L; de Haas, Y; Veerkamp, R F

    2013-10-01

    Genomic selection holds the promise to be particularly beneficial for traits that are difficult or expensive to measure, such that access to phenotypes on large daughter groups of bulls is limited. Instead, cow reference populations can be generated, potentially supplemented with existing information from the same or (highly) correlated traits available on bull reference populations. The objective of this study, therefore, was to develop a model to perform genomic predictions and genome-wide association studies based on a combined cow and bull reference data set, with the accuracy of the phenotypes differing between the cow and bull genomic selection reference populations. The developed bivariate Bayesian stochastic search variable selection model allowed for an unbalanced design by imputing residuals in the residual updating scheme for all missing records. The performance of this model is demonstrated on a real data example, where the analyzed trait, being milk fat or protein yield, was either measured only on a cow or a bull reference population, or recorded on both. Our results were that the developed bivariate Bayesian stochastic search variable selection model was able to analyze 2 traits, even though animals had measurements on only 1 of 2 traits. The Bayesian stochastic search variable selection model yielded consistently higher accuracy for fat yield compared with a model without variable selection, both for the univariate and bivariate analyses, whereas the accuracy of both models was very similar for protein yield. The bivariate model identified several additional quantitative trait loci peaks compared with the single-trait models on either trait. In addition, the bivariate models showed a marginal increase in accuracy of genomic predictions for the cow traits (0.01-0.05), although a greater increase in accuracy is expected as the size of the bull population increases. Our results emphasize that the chosen value of priors in Bayesian genomic prediction

  1. An Accuracy--Response Time Capacity Assessment Function that Measures Performance against Standard Parallel Predictions

    ERIC Educational Resources Information Center

    Townsend, James T.; Altieri, Nicholas

    2012-01-01

    Measures of human efficiency under increases in mental workload or attentional limitations are vital in studying human perception, cognition, and action. Assays of efficiency as workload changes have typically been confined to either reaction times (RTs) or accuracy alone. Within the realm of RTs, a nonparametric measure called the "workload…

  2. Predicting the Accuracy of Facial Affect Recognition: The Interaction of Child Maltreatment and Intellectual Functioning

    ERIC Educational Resources Information Center

    Shenk, Chad E.; Putnam, Frank W.; Noll, Jennie G.

    2013-01-01

    Previous research demonstrates that both child maltreatment and intellectual performance contribute uniquely to the accurate identification of facial affect by children and adolescents. The purpose of this study was to extend this research by examining whether child maltreatment affects the accuracy of facial recognition differently at varying…

  3. Psychological resilience predicts decreases in pain catastrophizing through positive emotions.

    PubMed

    Ong, Anthony D; Zautra, Alex J; Reid, M Carrington

    2010-09-01

    The study used a daily process design to examine the role of psychological resilience and positive emotions in the day-to-day experience of pain catastrophizing. A sample of 95 men and women with chronic pain completed initial assessments of neuroticism, psychological resilience, and demographic data, and then completed short diaries regarding pain intensity, pain catastrophizing, and positive and negative emotions every day for 14 consecutive days. Multilevel modeling analyses indicated that independent of level of neuroticism, negative emotions, pain intensity, income, and age, high-resilient individuals reported greater positive emotions and exhibited lower day-to-day pain catastrophizing compared with low-resilient individuals. Mediation analyses revealed that psychologically resilient individuals rebound from daily pain catastrophizing through experiences of positive emotion. Implications for research on psychological resilience, pain catastrophizing, and positive emotions are discussed.

  4. Positive feedback, memory, and the predictability of earthquakes

    PubMed Central

    Sammis, C. G.; Sornette, D.

    2002-01-01

    We review the “critical point” concept for large earthquakes and enlarge it in the framework of so-called “finite-time singularities.” The singular behavior associated with accelerated seismic release is shown to result from a positive feedback of the seismic activity on its release rate. The most important mechanisms for such positive feedback are presented. We solve analytically a simple model of geometrical positive feedback in which the stress shadow cast by the last large earthquake is progressively fragmented by the increasing tectonic stress. PMID:11875202

  5. Prediction of protein structural classes for low-similarity sequences using reduced PSSM and position-based secondary structural features.

    PubMed

    Wang, Junru; Wang, Cong; Cao, Jiajia; Liu, Xiaoqing; Yao, Yuhua; Dai, Qi

    2015-01-10

    Many efficient methods have been proposed to advance protein structural class prediction, but there are still some challenges where additional insight or technology is needed for low-similarity sequences. In this work, we schemed out a new prediction method for low-similarity datasets using reduced PSSM and position-based secondary structural features. We evaluated the proposed method with four experiments and compared it with the available competing prediction methods. The results indicate that the proposed method achieved the best performance among the evaluated methods, with overall accuracy 3-5% higher than the existing best-performing method. This paper also found that the reduced alphabets with size 13 simplify PSSM structures efficiently while reserving its maximal information. This understanding can be used to design more powerful prediction methods for protein structural class.

  6. [Discussion about the prediction accuracy for dynamic spectrum by partial FFT].

    PubMed

    Li, Gang; Li, Qiu-xia; Lin, Ling; Li, Xiao-xia; Wang, Yan; Liu, Yu-liang

    2006-12-01

    The development of near-infrared-based techniques for the noninvasive determination of blood component concentrations has attracted significant interest in recent years. But the noninvasive measurement of blood compositions has not yet been applied to the clinical field except blood oxygen saturation. The most important and also difficult problems are the effects of individual discrepancy and complicated measurement conditions. In the present article, the approach of dynamic spectrum (DS) is introduced, which is based on the principle of photoplethysmography. It is very difficult too to pick up DS with high precision in time domain. In order to extract the DS with high accuracy, the FFT method and it's leakage are discussed. The influences of sampling speed, sampling signal periodicity, window function and unsynchronized sample are analyzed by emulating experiments. The result of emulating experiments shows that choosing certain sampling speed, sampling signal periodicity, window function and interpolation arithmetic will improve accuracy observably. This provides necessary condition for the clinical application of DS.

  7. Computer-assisted orthognathic surgery: waferless maxillary positioning, versatility, and accuracy of an image-guided visualisation display.

    PubMed

    Zinser, Max J; Mischkowski, Robert A; Dreiseidler, Timo; Thamm, Oliver C; Rothamel, Daniel; Zöller, Joachim E

    2013-12-01

    There may well be a shift towards 3-dimensional orthognathic surgery when virtual surgical planning can be applied clinically. We present a computer-assisted protocol that uses surgical navigation supplemented by an interactive image-guided visualisation display (IGVD) to transfer virtual maxillary planning precisely. The aim of this study was to analyse its accuracy and versatility in vivo. The protocol consists of maxillofacial imaging, diagnosis, planning of virtual treatment, and intraoperative surgical transfer using an IGV display. The advantage of the interactive IGV display is that the virtually planned maxilla and its real position can be completely superimposed during operation through a video graphics array (VGA) camera, thereby augmenting the surgeon's 3-dimensional perception. Sixteen adult class III patients were treated with by bimaxillary osteotomy. Seven hard tissue variables were chosen to compare (ΔT1-T0) the virtual maxillary planning (T0) with the postoperative result (T1) using 3-dimensional cephalometry. Clinically acceptable precision for the surgical planning transfer of the maxilla (<0.35 mm) was seen in the anteroposterior and mediolateral angles, and in relation to the skull base (<0.35°), and marginal precision was seen in the orthogonal dimension (<0.64 mm). An interactive IGV display complemented surgical navigation, augmented virtual and real-time reality, and provided a precise technique of waferless stereotactic maxillary positioning, which may offer an alternative approach to the use of arbitrary splints and 2-dimensional orthognathic planning.

  8. Single-frequency receivers as master permanent stations in GNSS networks: precision and accuracy of the positioning in mixed networks

    NASA Astrophysics Data System (ADS)

    Dabove, Paolo; Manzino, Ambrogio Maria

    2015-04-01

    The use of GPS/GNSS instruments is a common practice in the world at both a commercial and academic research level. Since last ten years, Continuous Operating Reference Stations (CORSs) networks were born in order to achieve the possibility to extend a precise positioning more than 15 km far from the master station. In this context, the Geomatics Research Group of DIATI at the Politecnico di Torino has carried out several experiments in order to evaluate the achievable precision obtainable with different GNSS receivers (geodetic and mass-market) and antennas if a CORSs network is considered. This work starts from the research above described, in particular focusing the attention on the usefulness of single frequency permanent stations in order to thicken the existing CORSs, especially for monitoring purposes. Two different types of CORSs network are available today in Italy: the first one is the so called "regional network" and the second one is the "national network", where the mean inter-station distances are about 25/30 and 50/70 km respectively. These distances are useful for many applications (e.g. mobile mapping) if geodetic instruments are considered but become less useful if mass-market instruments are used or if the inter-station distance between master and rover increases. In this context, some innovative GNSS networks were developed and tested, analyzing the performance of rover's positioning in terms of quality, accuracy and reliability both in real-time and post-processing approach. The use of single frequency GNSS receivers leads to have some limits, especially due to a limited baseline length, the possibility to obtain a correct fixing of the phase ambiguity for the network and to fix the phase ambiguity correctly also for the rover. These factors play a crucial role in order to reach a positioning with a good level of accuracy (as centimetric o better) in a short time and with an high reliability. The goal of this work is to investigate about the

  9. Diagnostic accuracy of shear wave elastography for prediction of breast malignancy in patients with pathological nipple discharge

    PubMed Central

    Guo, Xiaobo; Liu, Ying; Li, Wanhu

    2016-01-01

    Objectives Pathological nipple discharge (PND) may indicate malignant breast lesions. As the role of shear wave elastography (SWE) in predicting these malignant lesions has not yet been evaluated, we aim to evaluate the diagnostic value of SWE for this condition. Design Prospective diagnostic accuracy study comparing a combination of qualitative and quantitative measurements of SWE (index test) to a ductoscopy and microdochectomy for histological diagnosis (reference test). Setting Fuzhou General Hospital of Nanjing military command. Participants A total of 379 patients with PND were finally included from January, 2011 to March 2014, after we screened 1084 possible candidates. All participants were evaluated through SWE, with qualitative parameters generated by Virtual Touch tissue imaging (VTI) and quantitative parameters generated by Virtual Touch tissue quantification (VTQ). All the patients were consented to receive a ductoscopy and microdochectomy for histological diagnosis, and the results were set as a reference test. Outcome measures Sensitivity and specificity of the combined VTI and VTQ of the SWE for detection of malignancy in patients with PND. Results The 379 participants presented with 404 lesions. The results of pathological examination showed that 326 (80.7%) of the 404 lesions were benign and the other 78 (19.3%) were malignant. An area under the curve of elasticity score, VTQm and VTQc, were 0.872, 0.825 and 0.857, respectively, with the corresponding cut-off point as 2.50, 2.860 m/s and 3.015 m/s, respectively. After a combination of these measurements, the sensitivity, specificity, and positive and negative predictive value (PPV and NPV), were 89.7%, 72.1%, 43.5% and 96.7%, respectively. The sensitivity analysis showed 82% of the sensitivity and 96.8% of the specificity, in which patients with no pathological findings in ductoscopy were excluded. Conclusions Ultrasonographic elastography is sensitive for patients with PND and could be used

  10. Positive and negative emotional contexts unevenly predict episodic memory.

    PubMed

    Martínez-Galindo, Joyce Graciela; Cansino, Selene

    2015-09-15

    The aim of this study was to investigate whether the recognition of faces with neutral expressions differs when they are encoded under different emotional contexts (positive, negative or non-emotional). The effects of the emotional valence context on the subsequent memory effect (SME) and the autonomic responses were also examined. Twenty-eight participants performed a betting-game task in which the faces of their virtual opponents were presented in each trial. The probability of winning or losing was manipulated to generate positive or negative contexts, respectively. Additionally, the participants performed the same task without betting as a non-emotional condition. After the encoding phase, an old/new paradigm was performed for the faces of the virtual opponents. The recognition was superior for the faces encoded in the positive contexts than for the faces encoded in the non-emotional contexts. The skin conductance response amplitude was equivalent for both of the emotional contexts. The N170 and P300 components at occipital sites and the frontal slow wave manifested SMEs that were modulated by positive contexts; neither negative nor non-emotional contexts influenced these effects. The behavioral and neurophysiological data demonstrated that positive contexts are stronger predictors of episodic memory than negative or non-emotional contexts.

  11. Does tumor size improve the accuracy of prognostic prediction in patients with esophageal squamous cell carcinoma after surgical resection?

    PubMed Central

    Gao, Yongyin; Shang, Xiaobin; Gong, Lei; Ma, Zhao; Yang, Mingjian; Jiang, Hongjing; Zhan, Zhongli; Meng, Bin; Yu, Zhentao

    2016-01-01

    This study aimed to investigate whether the inclusion of tumor size could improve the prognostic accuracy in patients with esophageal squamous cell cancer (ESCC). A total of 387 patients with ESCC who underwent curative resection were enrolled in this analysis. The patients were categorized into small-sized tumors (SSTs) and large-sized tumors (LSTs) using an appropriate cut-off point for tumor size. Kaplan–Meier survival curve and log–rank test were used to evaluate the prognostic value of tumor size. A Cox regression model was adopted for multivariate analysis. Their accuracy was compared based on the presence or absence of tumor size. Using 3.5 cm as the optimal cut-off point, 228 and 159 patients presented with LSTs (≥ 3.5 cm) and SSTs (< 3.5 cm), respectively. The patients with LSTs had significantly worse prognoses than patients with SSTs (23.9% vs. 43.2%, P < 0.001). Multivariate analysis revealed that tumor size, histological type, invasion depth, and lymph node metastasis were independent predictors of overall survival. The addition of tumor size to the AJCC TNM staging improved the predictive accuracy of the 5-year survival rate by 3.9%. Further study showed that tumor size and T stage were independent predictors of the prognosis of node-negative patients, and the combination of tumor size and T stage improved the predictive accuracy by 3.7%. In conclusion, tumor size is indeed a simple and practical prognostic factor in patients with ESCC. It can be used to improve the prognostic accuracy of the current TNM staging, especially for patients with node-negative disease. PMID:27579613

  12. A technique to improve the accuracy of Earth orientation prediction algorithms based on least squares extrapolation

    NASA Astrophysics Data System (ADS)

    Guo, J. Y.; Li, Y. B.; Dai, C. L.; Shum, C. K.

    2013-10-01

    We present a technique to improve the least squares (LS) extrapolation of Earth orientation parameters (EOPs), consisting of fixing the last observed data point on the LS extrapolation curve, which customarily includes a polynomial and a few sinusoids. For the polar motion (PM), a more sophisticated two steps approach has been developed, which consists of estimating the amplitude of the more stable one of the annual (AW) and Chandler (CW) wobbles using data of longer time span, and then estimating the other parameters using a shorter time span. The technique is studied using hindcast experiments, and justified using year-by-year statistics of 8 years. In order to compare with the official predictions of the International Earth Rotation and Reference Systems Service (IERS) performed at the U.S. Navy Observatory (USNO), we have enforced short-term predictions by applying the ARIMA method to the residuals computed by subtracting the LS extrapolation curve from the observation data. The same as at USNO, we have also used atmospheric excitation function (AEF) to further improve predictions of UT1-UTC. As results, our short-term predictions are comparable to the USNO predictions, and our long-term predictions are marginally better, although not for every year. In addition, we have tested the use of AEF and oceanic excitation function (OEF) in PM prediction. We find that use of forecasts of AEF alone does not lead to any apparent improvement or worsening, while use of forecasts of AEF + OEF does lead to apparent improvement.

  13. Effect of accuracy of wind power prediction on power system operator

    NASA Technical Reports Server (NTRS)

    Schlueter, R. A.; Sigari, G.; Costi, T.

    1985-01-01

    This research project proposed a modified unit commitment that schedules connection and disconnection of generating units in response to load. A modified generation control is also proposed that controls steam units under automatic generation control, fast responding diesels, gas turbines and hydro units under a feedforward control, and wind turbine array output under a closed loop array control. This modified generation control and unit commitment require prediction of trend wind power variation one hour ahead and the prediction of error in this trend wind power prediction one half hour ahead. An improved meter for predicting trend wind speed variation is developed. Methods for accurately simulating the wind array power from a limited number of wind speed prediction records was developed. Finally, two methods for predicting the error in the trend wind power prediction were developed. This research provides a foundation for testing and evaluating the modified unit commitment and generation control that was developed to maintain operating reliability at a greatly reduced overall production cost for utilities with wind generation capacity.

  14. Predictive accuracy of a ground-water model--Lessons from a postaudit

    USGS Publications Warehouse

    Konikow, Leonard F.

    1986-01-01

    Hydrogeologic studies commonly include the development, calibration, and application of a deterministic simulation model. To help assess the value of using such models to make predictions, a postaudit was conducted on a previously studied area in the Salt River and lower Santa Cruz River basins in central Arizona. A deterministic, distributed-parameter model of the ground-water system in these alluvial basins was calibrated by Anderson (1968) using about 40 years of data (1923–64). The calibrated model was then used to predict future water-level changes during the next 10 years (1965–74). Examination of actual water-level changes in 77 wells from 1965–74 indicates a poor correlation between observed and predicted water-level changes. The differences have a mean of 73 ft that is, predicted declines consistently exceeded those observed and a standard deviation of 47 ft. The bias in the predicted water-level change can be accounted for by the large error in the assumed total pumpage during the prediction period. However, the spatial distribution of errors in predicted water-level change does not correlate with the spatial distribution of errors in pumpage. Consequently, the lack of precision probably is not related only to errors in assumed pumpage, but may indicate the presence of other sources of error in the model, such as the two-dimensional representation of a three-dimensional problem or the lack of consideration of land-subsidence processes. This type of postaudit is a valuable method of verifying a model, and an evaluation of predictive errors can provide an increased understanding of the system and aid in assessing the value of undertaking development of a revised model.

  15. Accuracy of the Chinese lunar calendar method to predict a baby's sex: a population-based study.

    PubMed

    Villamor, Eduardo; Dekker, Louise; Svensson, Tobias; Cnattingius, Sven

    2010-07-01

    We estimated the accuracy of a non-invasive, inexpensive method (the Chinese lunar calendar, CLC) to predict the sex of a baby from around the time of conception, using 2,840,755 singleton births occurring in Sweden between 1973 and 2006. Maternal lunar age and month of conception were estimated, and used to predict each baby's sex, according to a published algorithm. Kappa statistics were estimated for the actual vs. the CLC-predicted sex of the baby. Overall kappa was 0.0002 [95% CI -0.0009, 0.0014]. Accuracy was not modified by year of conception, maternal age, level of education, body mass index or parity. In a validation subset of 1000 births in which we used a website-customised algorithm to estimate lunar dates, kappa was -0.02 [95% CI -0.08, 0.04]. Simulating the misuse of the method by failing to convert Gregorian dates into lunar did not change the results. We conclude that the CLC method is no better at predicting the sex of a baby than tossing a coin and advise against painting the nursery based on this method's result.

  16. Does Positive Youth Development Predict Adolescent Attitudes about Sexuality?

    ERIC Educational Resources Information Center

    Chapman, Erin N.; Werner-Wilson, Ronald Jay

    2008-01-01

    The purpose of this study was to explore the relationships among individual factors, parental factors, involvement in activities, and adolescent attitudes regarding sex (the outcome variable). We suggest that Positive Youth Development (PYD) research and programming should include promoting healthy sexuality as an important developmental outcome…

  17. Dorsomedial prefrontal cortex activity predicts the accuracy in estimating others' preferences

    PubMed Central

    Kang, Pyungwon; Lee, Jongbin; Sul, Sunhae; Kim, Hackjin

    2013-01-01

    The ability to accurately estimate another person's preferences is crucial for a successful social life. In daily interactions, we often do this on the basis of minimal information. The aims of the present study were (a) to examine whether people can accurately judge others based only on a brief exposure to their appearances, and (b) to reveal the underlying neural mechanisms with functional magnetic resonance imaging (fMRI). Participants were asked to make guesses about unfamiliar target individuals' preferences for various items after looking at their faces for 3 s. The behavioral results showed that participants estimated others' preferences above chance level. The fMRI data revealed that higher accuracy in preference estimation was associated with greater activity in the dorsomedial prefrontal cortex (DMPFC) when participants were guessing the targets' preferences relative to thinking about their own preferences. These findings suggest that accurate estimations of others' preferences may require increased activity in the DMPFC. A functional connectivity analysis revealed that higher accuracy in preference estimation was related to increased functional connectivity between the DMPFC and the brain regions that are known to be involved in theory of mind processing, such as the temporoparietal junction (TPJ) and the posterior cingulate cortex (PCC)/precuneus, during correct vs. incorrect guessing trials. On the contrary, the tendency to refer to self-preferences when estimating others' preference was related to greater activity in the ventromedial prefrontal cortex. These findings imply that the DMPFC may be a core region in estimating the preferences of others and that higher accuracy may require stronger communication between the DMPFC and the TPJ and PCC/precuneus, part of a neural network known to be engaged in mentalizing. PMID:24324419

  18. Improving the Accuracy of a Heliocentric Potential (HCP) Prediction Model for the Aviation Radiation Dose

    NASA Astrophysics Data System (ADS)

    Hwang, Junga; Yoon, Kyoung-Won; Jo, Gyeongbok; Noh, Sung-Jun

    2016-12-01

    The space radiation dose over air routes including polar routes should be carefully considered, especially when space weather shows sudden disturbances such as coronal mass ejections (CMEs), flares, and accompanying solar energetic particle events. We recently established a heliocentric potential (HCP) prediction model for real-time operation of the CARI-6 and CARI-6M programs. Specifically, the HCP value is used as a critical input value in the CARI-6/6M programs, which estimate the aviation route dose based on the effective dose rate. The CARI-6/6M approach is the most widely used technique, and the programs can be obtained from the U.S. Federal Aviation Administration (FAA). However, HCP values are given at a one month delay on the FAA official webpage, which makes it difficult to obtain real-time information on the aviation route dose. In order to overcome this critical limitation regarding the time delay for space weather customers, we developed a HCP prediction model based on sunspot number variations (Hwang et al. 2015). In this paper, we focus on improvements to our HCP prediction model and update it with neutron monitoring data. We found that the most accurate method to derive the HCP value involves (1) real-time daily sunspot assessments, (2) predictions of the daily HCP by our prediction algorithm, and (3) calculations of the resultant daily effective dose rate. Additionally, we also derived the HCP prediction algorithm in this paper by using ground neutron counts. With the compensation stemming from the use of ground neutron count data, the newly developed HCP prediction model was improved.

  19. Seismic Network Performance Estimation: Comparing Predictions of Magnitude of Completeness and Location Accuracy to Observations from an Earthquake Catalogue

    NASA Astrophysics Data System (ADS)

    Spriggs, N.; Greig, D. W.; Ackerley, N. J.

    2014-12-01

    The design of seismic networks for the monitoring of induced seismicity is of critical importance. The recent introduction of regulations in various locations around the world (with more upcoming) has created a need for a priori confirmation that certain performance standards are met. We develop a tool to assess two key measures of network performance without an earthquake catalogue: magnitude of completeness and location accuracy. Site noise measurements are taken at existing seismic stations or as part of a noise survey. We then interpolate between measured values to determine a noise map for the entire region. The site noise is then summed with the instrument noise to determine the effective station noise at each of the proposed station locations. Location accuracy is evaluated by generating a covariance matrix that represents the error ellipsoid from the travel time derivatives (Peters and Crosson, 1972). To determine the magnitude of completeness we assume isotropic radiation and mandate a minimum signal to noise ratio for detection. For every gridpoint, we compute the Brune spectra for synthetic events and iterate to determine the smallest magnitude event that can be detected by at least four stations. We apply this methodology to an example network. We predict the magnitude of completeness and the location accuracy and compare the predicted values to observed values generated from the existing earthquake catalogue for the network. We discuss the effects of hypothetical station additions and removals on network performance to simulate network expansions and station failures. The ability to predict hypothetical station performance allows for the optimization of seismic network design and enables prediction of network performance even for a purely hypothetical seismic network. This allows the operators of networks for induced seismicity monitoring to be confident that performance criteria are met from day one of operations.

  20. Evolutionary-guided de novo structure prediction of self-associated transmembrane helical proteins with near-atomic accuracy

    PubMed Central

    Wang, Y.; Barth, P.

    2016-01-01

    How specific protein associations regulate the function of membrane receptors remains poorly understood. Conformational flexibility currently hinders the structure determination of several classes of membrane receptors and associated oligomers. Here we develop EFDOCK-TM, a general method to predict self-associated transmembrane protein helical (TMH) structures from sequence guided by co-evolutionary information. We show that accurate intermolecular contacts can be identified using a combination of protein sequence covariation and TMH binding surfaces predicted from sequence. When applied to diverse TMH oligomers, including receptors characterized in multiple conformational and functional states, the method reaches unprecedented near-atomic accuracy for most targets. Blind predictions of structurally uncharacterized receptor tyrosine kinase TMH oligomers provide a plausible hypothesis on the molecular mechanisms of disease-associated point mutations and binding surfaces for the rational design of selective inhibitors. The method sets the stage for uncovering novel determinants of molecular recognition and signalling in single-spanning eukaryotic membrane receptors. PMID:25995083

  1. Evolutionary-guided de novo structure prediction of self-associated transmembrane helical proteins with near-atomic accuracy

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Barth, P.

    2015-05-01

    How specific protein associations regulate the function of membrane receptors remains poorly understood. Conformational flexibility currently hinders the structure determination of several classes of membrane receptors and associated oligomers. Here we develop EFDOCK-TM, a general method to predict self-associated transmembrane protein helical (TMH) structures from sequence guided by co-evolutionary information. We show that accurate intermolecular contacts can be identified using a combination of protein sequence covariation and TMH binding surfaces predicted from sequence. When applied to diverse TMH oligomers, including receptors characterized in multiple conformational and functional states, the method reaches unprecedented near-atomic accuracy for most targets. Blind predictions of structurally uncharacterized receptor tyrosine kinase TMH oligomers provide a plausible hypothesis on the molecular mechanisms of disease-associated point mutations and binding surfaces for the rational design of selective inhibitors. The method sets the stage for uncovering novel determinants of molecular recognition and signalling in single-spanning eukaryotic membrane receptors.

  2. Accuracy of patient's turnover time prediction using RFID technology in an academic ambulatory surgery center.

    PubMed

    Marchand-Maillet, Florence; Debes, Claire; Garnier, Fanny; Dufeu, Nicolas; Sciard, Didier; Beaussier, Marc

    2015-02-01

    Patients flow in outpatient surgical unit is a major issue with regards to resource utilization, overall case load and patient satisfaction. An electronic Radio Frequency Identification Device (RFID) was used to document the overall time spent by the patients between their admission and discharge from the unit. The objective of this study was to evaluate how a RFID-based data collection system could provide an accurate prediction of the actual time for the patient to be discharged from the ambulatory surgical unit after surgery. This is an observational prospective evaluation carried out in an academic ambulatory surgery center (ASC). Data on length of stay at each step of the patient care, from admission to discharge, were recorded by a RFID device and analyzed according to the type of surgical procedure, the surgeon and the anesthetic technique. Based on these initial data (n = 1520), patients were scheduled in a sequential manner according to the expected duration of the previous case. The primary endpoint was the difference between actual and predicted time of discharge from the unit. A total of 414 consecutive patients were prospectively evaluated. One hundred seventy four patients (42%) were discharged at the predicted time ± 30 min. Only 24% were discharged behind predicted schedule. Using an automatic record of patient's length of stay would allow an accurate prediction of the discharge time according to the type of surgery, the surgeon and the anesthetic procedure.

  3. Optimism predicts positive health in repatriated prisoners of war.

    PubMed

    Segovia, Francine; Moore, Jeffrey L; Linnville, Steven E; Hoyt, Robert E

    2015-05-01

    "Positive health," defined as a state beyond the mere absence of disease, was used as a model to examine factors for enhancing health despite extreme trauma. The study examined the United States' longest detained American prisoners of war, those held in Vietnam in the 1960s through early 1970s. Positive health was measured using a physical and a psychological composite score for each individual, based on 9 physical and 9 psychological variables. Physical and psychological health was correlated with optimism obtained postrepatriation (circa 1973). Linear regressions were employed to determine which variables contributed most to health ratings. Optimism was the strongest predictor of physical health (β = -.33, t = -2.73, p = .008), followed by fewer sleep complaints (β = -.29, t = -2.52, p = .01). This model accounted for 25% of the variance. Optimism was also the strongest predictor of psychological health (β = -.41, t = -2.87, p = .006), followed by Minnesota Multiphasic Personality Inventory-Psychopathic Deviate (MMPI-PD; McKinley & Hathaway, 1944) scores (β = -.23, t = -1.88, p = .07). This model strongly suggests that optimism is a significant predictor of positive physical and psychological health, and optimism also provides long-term protective benefits. These findings and the utility of this model suggest a promising area for future research and intervention.

  4. Method for enhanced accuracy in predicting peptides using liquid separations or chromatography

    DOEpatents

    Kangas, Lars J.; Auberry, Kenneth J.; Anderson, Gordon A.; Smith, Richard D.

    2006-11-14

    A method for predicting the elution time of a peptide in chromatographic and electrophoretic separations by first providing a data set of known elution times of known peptides, then creating a plurality of vectors, each vector having a plurality of dimensions, and each dimension representing the elution time of amino acids present in each of these known peptides from the data set. The elution time of any protein is then be predicted by first creating a vector by assigning dimensional values for the elution time of amino acids of at least one hypothetical peptide and then calculating a predicted elution time for the vector by performing a multivariate regression of the dimensional values of the hypothetical peptide using the dimensional values of the known peptides. Preferably, the multivariate regression is accomplished by the use of an artificial neural network and the elution times are first normalized using a transfer function.

  5. Improving the Accuracy of Predicting Maximal Oxygen Consumption (VO2pk)

    NASA Technical Reports Server (NTRS)

    Downs, Meghan E.; Lee, Stuart M. C.; Ploutz-Snyder, Lori; Feiveson, Alan

    2016-01-01

    Maximal oxygen (VO2pk) is the maximum amount of oxygen that the body can use during intense exercise and is used for benchmarking endurance exercise capacity. The most accurate method to determineVO2pk requires continuous measurements of ventilation and gas exchange during an exercise test to maximal effort, which necessitates expensive equipment, a trained staff, and time to set-up the equipment. For astronauts, accurate VO2pk measures are important to assess mission critical task performance capabilities and to prescribe exercise intensities to optimize performance. Currently, astronauts perform submaximal exercise tests during flight to predict VO2pk; however, while submaximal VO2pk prediction equations provide reliable estimates of mean VO2pk for populations, they can be unacceptably inaccurate for a given individual. The error in current predictions and logistical limitations of measuring VO2pk, particularly during spaceflight, highlights the need for improved estimation methods.

  6. Prediction of the disulfide-bonding state of cysteines in proteins at 88% accuracy

    PubMed Central

    Martelli, Pier Luigi; Fariselli, Piero; Malaguti, Luca; Casadio, Rita

    2002-01-01

    The task of predicting the cysteine-bonding state in proteins starting from the residue chain is addressed by implementing a new hybrid system that combines a neural network and a hidden Markov model (hidden neural network). Training is performed using 4136 cysteine-containing segments extracted from 969 nonhomologous proteins of well-resolved three-dimensional structure. After a 20-fold cross-validation procedure, the efficiency of the prediction scores as high as 88% and 84%, when measured on cysteine and protein basis, respectively. These results outperform previously described methods for the same task. PMID:12381855

  7. Predictive Accuracy of 29-Comorbidity Index for In-Hospital Deaths in US Adult Hospitalizations with a Diagnosis of Venous Thromboembolism

    PubMed Central

    Tsai, James; Abe, Karon; Boulet, Sheree L.; Beckman, Michele G.; Hooper, W. Craig; Grant, Althea M.

    2013-01-01

    Background Venous thromboembolism (VTE), comprising deep vein thrombosis (DVT) and pulmonary embolism (PE), is a significant source of mortality and morbidity worldwide. By analyzing data of the 2010 Nationwide Inpatient Sample from the Agency for Healthcare Research and Quality (AHRQ), we evaluated the predictive accuracy of the AHRQ’s 29-comorbidity index with in-hospital death among US adult hospitalizations with a diagnosis of VTE. Methods We assessed the case-fatality and prevalence of comorbidities among a sample of 153,518 adult hospitalizations with a diagnosis of VTE that comprised 87,605 DVTs and 65,913 PEs (with and without DVT). We estimated adjusted odds ratios and 95% confidence intervals with multivariable logistic regression models by using comorbidities as predictors and status of in-hospital death as an outcome variable. We assessed the c-statistics for the predictive accuracy of the logistic regression models. Results In 2010, approximately 41,944 in-hospital deaths (20,212 with DVT and 21,732 with PE) occurred among 770,137 hospitalizations with a diagnosis of VTE. When compared separately to hospitalizations with VTE, DVT, or PE that had no corresponding comorbidities, congestive heart failure, chronic pulmonary disease, coagulopathy, liver disease, lymphoma, fluid and electrolyte disorders, metastatic cancer, other neurological disorders, peripheral vascular disorders, pulmonary circulation disorders, renal failure, solid tumor without metastasis, and weight loss were positively and independently associated with 10%−125% increased likelihoods of in-hospital death. The c-statistic values ranged from 0.776 to 0.802. Conclusion The results of this study indicated that comorbidity was associated independently with risk of death among hospitalizations with VTE and among hospitalizations with DVT or PE. The AHRQ 29-comorbidity index provides acceptable to excellent predictive accuracy for in-hospital deaths among adult hospitalizations with VTE

  8. An Other Perspective on Personality: Meta-Analytic Integration of Observers' Accuracy and Predictive Validity

    ERIC Educational Resources Information Center

    Connelly, Brian S.; Ones, Deniz S.

    2010-01-01

    The bulk of personality research has been built from self-report measures of personality. However, collecting personality ratings from other-raters, such as family, friends, and even strangers, is a dramatically underutilized method that allows better explanation and prediction of personality's role in many domains of psychology. Drawing…

  9. Further Evaluation of the Accuracy of Managerial Prediction of Employee Preference

    ERIC Educational Resources Information Center

    Wilder, David A.; Harris, Carelle; Casella, Sarah; Wine, Byron; Postma, Nicki

    2011-01-01

    Previous research (i.e., Wilder, Rost, & McMahon, 2007) has suggested that managers perform poorly when predicting items and activities which their employees state that they might like to earn as part of performance improvement programs. The purpose of the current study was to replicate the earlier study conducted by Wilder et al. (2007) with a…

  10. The Accuracy of Managerial Prediction of Employee Preference: A Brief Report

    ERIC Educational Resources Information Center

    Wilder, David A.; Rost, Kristen; McMahon, Meghan

    2007-01-01

    The extent to which managers could accurately predict what items/activities their employees report as preferred was examined. First, managers were asked to rank order a list of items/activities they thought their employees would most prefer to be incorporated into a performance improvement plan. Next, employee preference for these same items was…

  11. Beware of R2: simple, unambiguous assessment of the prediction accuracy of QSAR and QSPR models

    PubMed Central

    Alexander, D. L. J.; Tropsha, A.; Winkler, David A.

    2015-01-01

    The statistical metrics used to characterize the external predictivity of a model, i.e., how well it predicts the properties of an independent test set, have proliferated over the past decade. This paper clarifies some apparent confusion over the use of the coefficient of determination, R2, as a measure of model fit and predictive power in QSAR and QSPR modelling. R2 (or R2) has been used in various contexts in the literature in conjunction with training and test data, for both ordinary linear regression and regression through the origin as well as with linear and nonlinear regression models. We analyze the widely adopted model fit criteria suggested by Golbraikh and Tropsha1 in a strict statistical manner. Shortcomings in these criteria are identified and a clearer and simpler alternative method to characterize model predictivity is provided. The intent is not to repeat the well-documented arguments for model validation using test data, but to guide the application of R2 as a model fit statistic. Examples are used to illustrate both correct and incorrect use of R2. Reporting the root mean squared error or equivalent measures of dispersion, typically of more practical importance than R2, is also encouraged and important challenges in addressing the needs of different categories of users such as computational chemists, experimental scientists, and regulatory decision support specialists are outlined. PMID:26099013

  12. Right Temporoparietal Gray Matter Predicts Accuracy of Social Perception in the Autism Spectrum

    ERIC Educational Resources Information Center

    David, Nicole; Schultz, Johannes; Milne, Elizabeth; Schunke, Odette; Schöttle, Daniel; Münchau, Alexander; Siegel, Markus; Vogeley, Kai; Engel, Andreas K.

    2014-01-01

    Individuals with an autism spectrum disorder (ASD) show hallmark deficits in social perception. These difficulties might also reflect fundamental deficits in integrating visual signals. We contrasted predictions of a social perception and a spatial-temporal integration deficit account. Participants with ASD and matched controls performed two…

  13. Accuracy of the DIBELS Oral Reading Fluency Measure for Predicting Third Grade Reading Comprehension Outcomes

    ERIC Educational Resources Information Center

    Roehrig, Alysia D.; Petscher, Yaacov; Nettles, Stephen M.; Hudson, Roxanne F.; Torgesen, Joseph K.

    2008-01-01

    We evaluated the validity of DIBELS ("Dynamic Indicators of Basic Early Literacy Skills") ORF ("Oral Reading Fluency") for predicting performance on the "Florida Comprehensive Assessment Test" (FCAT-SSS) and "Stanford Achievement Test" (SAT-10) reading comprehension measures. The usefulness of previously…

  14. Diagnostic accuracy of a mathematical model to predict apnea-hypopnea index using nighttime pulse oximetry

    NASA Astrophysics Data System (ADS)

    Ebben, Matthew R.; Krieger, Ana C.

    2016-03-01

    The intent of this study is to develop a predictive model to convert an oxygen desaturation index (ODI) to an apnea-hypopnea index (AHI). This model will then be compared to actual AHI to determine its precision. One thousand four hundred and sixty-seven subjects given polysomnograms with concurrent pulse oximetry between April 14, 2010, and February 7, 2012, were divided into model development (n=733) and verification groups (n=734) in order to develop a predictive model of AHI using ODI. Quadratic regression was used for model development. The coefficient of determination (r2) between the actual AHI and the predicted AHI (PredAHI) was 0.80 (r=0.90), which was significant at a p<0.001. The areas under the receiver operating characteristic curve ranged from 0.96 for AHI thresholds of ≥10 and ≥15/h to 0.97 for thresholds of ≥5 and ≥30/h. The algorithm described in this paper provides a convenient and accurate way to convert ODI to a predicted AHI. This tool makes it easier for clinicians to understand oximetry data in the context of traditional measures of sleep apnea.

  15. Increased prediction accuracy in wheat breeding trials using a marker x environment interaction genomic selection model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genomic selection (GS) models use genome-wide genetic information to predict genetic values of candidates for selection. Originally these models were developed without considering genotype ' environment interaction (GE). Several authors have proposed extensions of the cannonical GS model that accomm...

  16. Genomic selection accuracy using multi-family prediction models in a wheat breeding program

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genomic selection (GS) uses genome-wide molecular marker data to predict the genetic value of selection candidates in breeding programs. In plant breeding, the ability to produce large numbers of progeny per cross allows GS to be conducted within each family. However, this approach requires phenotyp...

  17. Prediction of nucleosome DNA formation potential and nucleosome positioning using increment of diversity combined with quadratic discriminant analysis.

    PubMed

    Zhao, Xiujuan; Pei, Zhiyong; Liu, Jia; Qin, Sheng; Cai, Lu

    2010-11-01

    In this work, a novel method was developed to distinguish nucleosome DNA and linker DNA based on increment of diversity combined with quadratic discriminant analysis (IDQD), using k-mer frequency of nucleotides in genome. When used to predict DNA potential for forming nucleosomes, the model achieved a high accuracy of 94.94%, 77.60%, and 86.81%, respectively, for Saccharomyces cerevisiae, Homo sapiens, and Drosophila melanogaster. The area under the receiver operator characteristics curve of our classifier was 0.982 for S. cerevisiae. Our results indicate that DNA sequence preference is critical for nucleosome formation potential and is likely conserved across eukaryotes. The model successfully identified nucleosome-enriched or nucleosome-depleted regions in S. cerevisiae genome, suggesting nucleosome positioning depends on DNA sequence preference. Thus, IDQD classifier is useful for predicting nucleosome positioning.

  18. Positive predictive value of cholescintigraphy in common bile duct obstruction

    SciTech Connect

    Lecklitner, M.L.; Austin, A.R.; Benedetto, A.R.; Growcock, G.W.

    1986-09-01

    Technetium-99m DISIDA imaging was employed in 400 patients to differentiate obstruction of the common bile duct from medical and other surgical causes of hyperbilirubinemia. Sequential anterior images demonstrated variable degrees of liver uptake, yet there was no evidence of intrabiliary or extrabiliary radioactivity for at least 4 hr after injection in 25 patients. Twenty-three patients were surgically documented to have complete obstruction of the common bile duct. One patient had hepatitis, and another had sickle cell crisis without bile duct obstruction. The remaining patients had either partial or no obstruction of the common bile duct. We conclude that the presence of liver uptake without evident biliary excretion by 4 hr on cholescintigraphy is highly sensitive and predictive of total obstruction of the common bile duct.

  19. Cortico-striatal connections predict control over speed and accuracy in perceptual decision making.

    PubMed

    Forstmann, Birte U; Anwander, Alfred; Schäfer, Andreas; Neumann, Jane; Brown, Scott; Wagenmakers, Eric-Jan; Bogacz, Rafal; Turner, Robert

    2010-09-07

    When people make decisions they often face opposing demands for response speed and response accuracy, a process likely mediated by response thresholds. According to the striatal hypothesis, people decrease response thresholds by increasing activation from cortex to striatum, releasing the brain from inhibition. According to the STN hypothesis, people decrease response thresholds by decreasing activation from cortex to subthalamic nucleus (STN); a decrease in STN activity is likewise thought to release the brain from inhibition and result in responses that are fast but error-prone. To test these hypotheses-both of which may be true-we conducted two experiments on perceptual decision making in which we used cues to vary the demands for speed vs. accuracy. In both experiments, behavioral data and mathematical model analyses confirmed that instruction from the cue selectively affected the setting of response thresholds. In the first experiment we used ultra-high-resolution 7T structural MRI to locate the STN precisely. We then used 3T structural MRI and probabilistic tractography to quantify the connectivity between the relevant brain areas. The results showed that participants who flexibly change response thresholds (as quantified by the mathematical model) have strong structural connections between presupplementary motor area and striatum. This result was confirmed in an independent second experiment. In general, these findings show that individual differences in elementary cognitive tasks are partly driven by structural differences in brain connectivity. Specifically, these findings support a cortico-striatal control account of how the brain implements adaptive switches between cautious and risky behavior.

  20. The use of imprecise processing to improve accuracy in weather & climate prediction

    NASA Astrophysics Data System (ADS)

    Düben, Peter D.; McNamara, Hugh; Palmer, T. N.

    2014-08-01

    The use of stochastic processing hardware and low precision arithmetic in atmospheric models is investigated. Stochastic processors allow hardware-induced faults in calculations, sacrificing bit-reproducibility and precision in exchange for improvements in performance and potentially accuracy of forecasts, due to a reduction in power consumption that could allow higher resolution. A similar trade-off is achieved using low precision arithmetic, with improvements in computation and communication speed and savings in storage and memory requirements. As high-performance computing becomes more massively parallel and power intensive, these two approaches may be important stepping stones in the pursuit of global cloud-resolving atmospheric modelling. The impact of both hardware induced faults and low precision arithmetic is tested using the Lorenz '96 model and the dynamical core of a global atmosphere model. In the Lorenz '96 model there is a natural scale separation; the spectral discretisation used in the dynamical core also allows large and small scale dynamics to be treated separately within the code. Such scale separation allows the impact of lower-accuracy arithmetic to be restricted to components close to the truncation scales and hence close to the necessarily inexact parametrised representations of unresolved processes. By contrast, the larger scales are calculated using high precision deterministic arithmetic. Hardware faults from stochastic processors are emulated using a bit-flip model with different fault rates. Our simulations show that both approaches to inexact calculations do not substantially affect the large scale behaviour, provided they are restricted to act only on smaller scales. By contrast, results from the Lorenz '96 simulations are superior when small scales are calculated on an emulated stochastic processor than when those small scales are parametrised. This suggests that inexact calculations at the small scale could reduce computation and

  1. The use of imprecise processing to improve accuracy in weather and climate prediction

    SciTech Connect

    Düben, Peter D.; McNamara, Hugh; Palmer, T.N.

    2014-08-15

    The use of stochastic processing hardware and low precision arithmetic in atmospheric models is investigated. Stochastic processors allow hardware-induced faults in calculations, sacrificing bit-reproducibility and precision in exchange for improvements in performance and potentially accuracy of forecasts, due to a reduction in power consumption that could allow higher resolution. A similar trade-off is achieved using low precision arithmetic, with improvements in computation and communication speed and savings in storage and memory requirements. As high-performance computing becomes more massively parallel and power intensive, these two approaches may be important stepping stones in the pursuit of global cloud-resolving atmospheric modelling. The impact of both hardware induced faults and low precision arithmetic is tested using the Lorenz '96 model and the dynamical core of a global atmosphere model. In the Lorenz '96 model there is a natural scale separation; the spectral discretisation used in the dynamical core also allows large and small scale dynamics to be treated separately within the code. Such scale separation allows the impact of lower-accuracy arithmetic to be restricted to components close to the truncation scales and hence close to the necessarily inexact parametrised representations of unresolved processes. By contrast, the larger scales are calculated using high precision deterministic arithmetic. Hardware faults from stochastic processors are emulated using a bit-flip model with different fault rates. Our simulations show that both approaches to inexact calculations do not substantially affect the large scale behaviour, provided they are restricted to act only on smaller scales. By contrast, results from the Lorenz '96 simulations are superior when small scales are calculated on an emulated stochastic processor than when those small scales are parametrised. This suggests that inexact calculations at the small scale could reduce computation and

  2. Predicting nucleosome positioning based on geometrically transformed Tsallis entropy.

    PubMed

    Wu, Jing; Zhang, Yusen; Mu, Zengchao

    2014-01-01

    As the fundamental unit of eukaryotic chromatin structure, nucleosome plays critical roles in gene expression and regulation by controlling physical access to transcription factors. In this paper, based on the geometrically transformed Tsallis entropy and two index-vectors, a valid nucleosome positioning information model is developed to describe the distribution of A/T-riched and G/C-riched dimeric and trimeric motifs along the DNA duplex. When applied to train the support vector machine, the model achieves high AUCs across five organisms, which have significantly outperformed the previous studies. Besides, we adopt the concept of relative distance to describe the probability of arbitrary DNA sequence covered by nucleosome. Thus, the average nucleosome occupancy profile over the S.cerevisiae genome is calculated. With our peak detection model, the isolated nucleosomes along genome sequence are located. When compared with some published results, it shows that our model is effective for nucleosome positioning. The index-vector component [Formula in text] is identified to be an important influencing factor of nucleosome organizations.

  3. Validating a Hazardous Drinking Index in a Sample of Sexual Minority Women: Reliability, Validity and Predictive Accuracy

    PubMed Central

    Riley, Barth B.; Hughes, Tonda L.; Wilsnack, Sharon C.; Johnson, Timothy P.; Benson, Perry; Aranda, Frances

    2017-01-01

    Background Although sexual minority women (SMW) are at increased risk of hazardous drinking (HD), efforts to validate HD measures have yet to focus on this population. Objectives Validation of a 13-item Hazardous Drinking Index (HDI) in a large sample of SMW. Methods Data were from 700 adult SMW (age 18–82) enrolled in the Chicago Health and Life Experiences of Women study. Criterion measures included counts of depressive symptoms and post-traumatic stress disorder (PTSD) symptoms, average daily and 30-day ethanol consumption, risky sexual behavior, and Diagnostic and Statistical Manual (DSM-IV) measures of alcohol abuse/dependence. Analyses included assessment of internal consistency, construction of receiver operating characteristic (ROC) curves to predict alcohol abuse/dependence, and correlations between HDI and criterion measures. We compared the psychometric properties (diagnostic accuracy and correlates of hazardous drinking) of the HDI to the commonly used CAGE instrument. Results KR-20 reliability for the HDI was 0.80, compared to 0.74 for the CAGE. Predictive accuracy, as measured by the area under the receiver operating characteristic curve for alcohol abuse/dependence, was HDI: 0.89; CAGE: 0.84. The HDI evidenced the best predictive efficacy and tradeoff between sensitivity and specificity. Results supported the concurrent validity of the HDI measure. Conclusions The Hazardous Drinking Index is a reliable and valid measure of hazardous drinking for sexual minority women. PMID:27661289

  4. Assessing the prediction accuracy of cure in the Cox proportional hazards cure model: an application to breast cancer data.

    PubMed

    Asano, Junichi; Hirakawa, Akihiro; Hamada, Chikuma

    2014-01-01

    A cure rate model is a survival model incorporating the cure rate with the assumption that the population contains both uncured and cured individuals. It is a powerful statistical tool for prognostic studies, especially in cancer. The cure rate is important for making treatment decisions in clinical practice. The proportional hazards (PH) cure model can predict the cure rate for each patient. This contains a logistic regression component for the cure rate and a Cox regression component to estimate the hazard for uncured patients. A measure for quantifying the predictive accuracy of the cure rate estimated by the Cox PH cure model is required, as there has been a lack of previous research in this area. We used the Cox PH cure model for the breast cancer data; however, the area under the receiver operating characteristic curve (AUC) could not be estimated because many patients were censored. In this study, we used imputation-based AUCs to assess the predictive accuracy of the cure rate from the PH cure model. We examined the precision of these AUCs using simulation studies. The results demonstrated that the imputation-based AUCs were estimable and their biases were negligibly small in many cases, although ordinary AUC could not be estimated. Additionally, we introduced the bias-correction method of imputation-based AUCs and found that the bias-corrected estimate successfully compensated the overestimation in the simulation studies. We also illustrated the estimation of the imputation-based AUCs using breast cancer data.

  5. Does positive youth development predict adolescent attitudes about sexuality?

    PubMed

    Chapman, Erin N; Werner-Wilson, Ronald Jay

    2008-01-01

    The purpose of this study was to explore the relationships among individual factors, parental factors, involvement in activities, and adolescent attitudes regarding sex (the outcome variable). We suggest that Positive Youth Development (PYD) research and programming should include promoting healthy sexuality as an important developmental outcome for youth. PYD philosophy and theory, bioecological theory (Bronfenbrenner & Morris, 1998), and identity development theory (Erikson, 1983, 1968; Marcia, 1980, 1993) provided the foundation for this study and were used to make the connections between PYD, adolescent sexuality (including attitudes and behavior), and aspects of the parent-adolescent relationship. Both self-esteem and sexual experience were significant predictors of attitudes regarding sex, but overall, parents contributed the most influence on the outcome variable. (It should be noted, however, that parental influence was the only factor that was a significant predictor.) Only one of the two involvements in activities variables was a significant predictor of attitudes regarding sex.

  6. Assessment of the accuracy of PPP for very-high-frequency dynamic, satellite positioning and earthquake modeling

    NASA Astrophysics Data System (ADS)

    Moschas, F.; Avallone, A.; Moschonas, N.; Saltogianni, V.; Stiros, S.

    2012-04-01

    With the advent of various GPS/GNSS Point Positioning techniques, it became possible to model the dynamic displacement history of specific points during large and rather moderate earthquakes using satellite positioning, 1Hz and occasionally 10Hz sampling data. While there is evidence that the obtained data are precise, experience from monitoring of engineering structures like bridges, indicates that GPS/GNSS records are contaminated by coloured (mostly background noise) noise even in the cases of differential-type analysis of the satellite signals. This made the necessary the assessment of the results of different PPP processing using supervised learning techniques. Our work was based on a modification of an experiment first made to assess the potential of GPS to measure oscillations of civil engineering structures. A 10Hz GNSS antenna-receiver unit was mounted on the top of a vertical rod, fixed on the ground and forced to controlled oscillations. Oscillations were also recorded by a robotic theodolite and an accelerometer, and the whole experiment was video-recorded. A second 10Hz GNSS antenna-receiver unit was left on stable ground, in a nearby position. The rod was forced to semi-static motion (bending) and then was left to oscillate freely until still, and the whole movement was recorded by all sensors. GNSS data were analyzed both in kinematic mode and in PPP mode, using the GIPSY-OASIS II (http://gipsy-oasis.jpl.nasa.gov) (only GPS) and the PPP CRCS facility (GPS + GLONAS). Recorded PPP and differential kinematic processing coordinates (apparent displacements) were found to follow the real motion, but to be contaminated by a long-period noise. On the contrary, the short-period component of the apparent PPP displacements, obtained using high-pass filtering, were very much consistent with the real motion, with sub-mm mean deviation, though occasionally contaminated by clipping. The assessment of the very-high frequency GPS noise will provide useful information

  7. A 3-D numerical study of pinhole diffraction to predict the accuracy of EUV point diffraction interferometry

    SciTech Connect

    Goldberg, K.A. |; Tejnil, E.; Bokor, J. |

    1995-12-01

    A 3-D electromagnetic field simulation is used to model the propagation of extreme ultraviolet (EUV), 13-nm, light through sub-1500 {Angstrom} dia pinholes in a highly absorptive medium. Deviations of the diffracted wavefront phase from an ideal sphere are studied within 0.1 numerical aperture, to predict the accuracy of EUV point diffraction interferometersused in at-wavelength testing of nearly diffraction-limited EUV optical systems. Aberration magnitudes are studied for various 3-D pinhole models, including cylindrical and conical pinhole bores.

  8. Prediction accuracy of various models for angle-of-arrival fluctuations

    NASA Astrophysics Data System (ADS)

    Porat, O.; Shapira, J.

    2016-03-01

    We have compared measured angle-of-arrival (AOA) fluctuations to the prediction of various models, for a laser beam propagating through a turbulent atmosphere at ground level. Three models have been investigated: a simple small perturbation model, a model which incorporates also inner and outer scale effects and a third model which takes into account the contribution of additional spatial scales and is able to predict a saturation regime. Data were collected in an approximately ten year time span. We have used near infra-red LIDAR systems to determine the AOA fluctuations by measuring the short term movement of a laser spot in the receiver plane, reflected from targets placed at various distances. In parallel, we have also measured the turbulence strength with a short-range scintilometer and recorded the average wind speed along the laser path. Our analysis indicates that the simple model predictions are quite good for weak turbulence and short distances, however on the majority of the scenarios the conditions (turbulence strength and distance) are such that the AOA fluctuations deviate from the simple model and even approach saturation. In these cases the fluctuations follows the general form of the third model. We also found some differences between the day and night behavior which wasn't considered by any of the models.

  9. Evaluation of accuracy and applicability of protein models: retrospective analysis of biological and biomedical predictions.

    PubMed

    Khan, Sofia; Vihinen, Mauno

    2009-01-01

    In order to study protein function and activity structural data is required. Since experimental structures are available for just a small fraction of all known protein sequences, computational methods such as protein modelling can provide useful information. Over the last few decades we have predicted, with homology modelling methods, the structures for numerous proteins. In this study we assess the structural quality and validity of the biological and medical interpretations and predictions made based on the models. All the models had correct scaffolding and were ranked at least as correct or good by numerical evaluators even though the sequence identity with the template was as low as 8%. The biological explanations made based on models were well in line with experimental structures and other experimental studies. Retrospective analysis of homology models indicates the power of protein modelling when made carefully from sequence alignment to model building and refinement. Modelling can be applied to studying and predicting different kinds of biological phenomena and according to our results it can be done so with success.

  10. Impact of time-variable vegetation on accuracy of rapid hydrologic predictions

    NASA Astrophysics Data System (ADS)

    Stec, Magdalena; Niedzielski, Tomasz

    2016-04-01

    It is crucial to identify the processes that impact errors of hydrologic forecasts. Since existence of vegetation and its ability to store precipitation is an important element of water distribution in the catchment, especially at the beginning of a rainfall event, it may be considered as one of the processes influencing skills of hydrological forecasts. The main objective of the study is to verify the hypothesis that water level predictions are controlled by vegetation dynamics in the contributing mountainous basins. The analysis is conducted for the upper Nysa Klodzka catchment with the outlet in Bardo (SW Poland). The basin includes a mid-mountain abasement covered with crops, while surrounding medium-altitude mountain ranges are mainly covered with forests. We focus on the entire year, from autumn 2013 to summer 2014. Herein, we analyze prediction errors and efficiency measures of hydrologic forecasts provided by two stochastic models - uni- and multivariate autoregressive models as well as their two-model ensemble prediction. In addition, we use the satellite-derived Leaf Area Index (LAI) images from the Moderate Resolution Imaging Spectroradiometer (MODIS). Hydrological prognoses are derived by the HydroProg real-time rapid forecasting system, built at the University of Wroclaw (Poland) in frame of the research project 2011/01/D/ST10/04171 of the National Science Centre of Poland. Correlation analysis between the plant maximum water storage capacity and prediction error/skill statistics (mean absolute error, root mean square error, Nash-Sutcliffe efficiency , index of agreement) is conducted. To cope with small sample size, the bootstrap simulation is performed. We conclude that there is a strong negative association between mean or median prediction errors and vegetation state for all meteorological seasons of a year. This result implies that basins with higher interception potential are more vulnerable to forecast inaccuracy than those with sparse natural

  11. Predicting College Students' Positive Psychology Associated Traits with Executive Functioning Dimensions

    ERIC Educational Resources Information Center

    Marshall, Seth

    2016-01-01

    More research is needed that investigates how positive psychology-associated traits are predicted by neurocognitive processes. Correspondingly, the purpose of this study was to ascertain how, and to what extent, four traits, namely, grit, optimism, positive affect, and life satisfaction were predicted by the executive functioning (EF) dimensions…

  12. Low numeracy predicts reduced accuracy of retrospective reports of frequency of sexual behavior.

    PubMed

    McAuliffe, Timothy L; DiFranceisco, Wayne; Reed, Barbara R

    2010-12-01

    Assessment of the frequency of sexual behavior relies on participants' ability to arithmetically aggregate information over time and across partners. This study examines the effect of numeracy (arithmetic skills) on the accuracy of retrospective reports of sexual behavior. For 91 days, the participants completed daily reports about their sexual activity. Participants then completed a survey on sexual behavior over the same period. The discrepancies between the survey-based and the diary-based measures of frequency of vaginal and anal intercourse were evaluated. Multiple regression analysis showed that the discrepancy between retrospective and diary measurements of sexual intercourse increased with lower numeracy (P = 0.026), lower education (P = 0.001), aggregate question format compared to partner-by-partner format (P = 0.031) and higher frequency of intercourse occasions (P < 0.001). Lower numeracy led to a 1.5-fold increase (adjusted mean = 14.1-20.9) in the discrepancy for those using the aggregate question format and a 2.0-fold increase (adjusted mean = 3.7-7.6) for those using the partner-by-partner format.

  13. Accuracy of density functional theory in the prediction of carbon dioxide adsorbent materials.

    PubMed

    Cazorla, Claudio; Shevlin, Stephen A

    2013-04-07

    Density functional theory (DFT) has become the computational method of choice for modeling and characterization of carbon dioxide adsorbents, a broad family of materials which at present are urgently sought after for environmental applications. The description of polar carbon dioxide (CO(2)) molecules in low-coordinated environments like surfaces and porous materials, however, may be challenging for local and semi-local DFT approximations. Here, we present a thorough computational study in which the accuracy of DFT methods in describing the interactions of CO(2) with model alkali-earth-metal (AEM, Ca and Li) decorated carbon structures, namely anthracene (C(14)H(10)) molecules, is assessed. We find that gas-adsorption energies and equilibrium structures obtained with standard (i.e. LDA and GGA), hybrid (i.e. PBE0 and B3LYP) and van der Waals exchange-correlation functionals of DFT dramatically differ from the results obtained with second-order Møller-Plesset perturbation theory (MP2), an accurate computational quantum chemistry method. The major disagreements found can be mostly rationalized in terms of electron correlation errors that lead to wrong charge-transfer and electrostatic Coulomb interactions between CO(2) and AEM-decorated anthracene molecules. Nevertheless, we show that when the concentration of AEM atoms in anthracene is tuned to resemble as closely as possible the electronic structure of AEM-decorated graphene (i.e. an extended two-dimensional material), hybrid exchange-correlation DFT and MP2 methods quantitatively provide similar results.

  14. The psychology of intelligence analysis: drivers of prediction accuracy in world politics.

    PubMed

    Mellers, Barbara; Stone, Eric; Atanasov, Pavel; Rohrbaugh, Nick; Metz, S Emlen; Ungar, Lyle; Bishop, Michael M; Horowitz, Michael; Merkle, Ed; Tetlock, Philip

    2015-03-01

    This article extends psychological methods and concepts into a domain that is as profoundly consequential as it is poorly understood: intelligence analysis. We report findings from a geopolitical forecasting tournament that assessed the accuracy of more than 150,000 forecasts of 743 participants on 199 events occurring over 2 years. Participants were above average in intelligence and political knowledge relative to the general population. Individual differences in performance emerged, and forecasting skills were surprisingly consistent over time. Key predictors were (a) dispositional variables of cognitive ability, political knowledge, and open-mindedness; (b) situational variables of training in probabilistic reasoning and participation in collaborative teams that shared information and discussed rationales (Mellers, Ungar, et al., 2014); and (c) behavioral variables of deliberation time and frequency of belief updating. We developed a profile of the best forecasters; they were better at inductive reasoning, pattern detection, cognitive flexibility, and open-mindedness. They had greater understanding of geopolitics, training in probabilistic reasoning, and opportunities to succeed in cognitively enriched team environments. Last but not least, they viewed forecasting as a skill that required deliberate practice, sustained effort, and constant monitoring of current affairs.

  15. On the accuracy of creep-damage predictions in thinwalled structures using the finite element method

    NASA Astrophysics Data System (ADS)

    Altenbach, H.; Kolarow, G.; Morachkovsky, O. K.; Naumenko, K.

    The constitutive model with a single damage parameter describing creep-damage behaviour of metals with respect to the different sensitivity of the damage process due to tension and compression is incorporated into the ANSYS finite element code by modifying the user defined creep material subroutine. The procedure is verified by comparison with solutions for beams and rectangular plates in bending based on the Ritz method. Various numerical tests show the sensitivity of long-term predictions to the mesh sizes and element types available for the creep analysis of thinwalled structures.

  16. SMP84: Improvements to Capability and Prediction Accuracy of the Standard Ship Motion Program SMP81

    DTIC Science & Technology

    1985-09-01

    8217*ceisay and .denPi by bicick nejenber) PUý, GOD SUBlGROUP Ship Matic~n Wave Induced 1,.oad% Irregular Sea Antiroll Fins Computer h~nual Maxiluin...using a different theory to compute hull lift dampin~g. New predictions were incorporated into SMP to compute stabilized ship responses for active...A-i v e ii• -~~v I.-~ -. 7 ---- ~ Page LIST GF FIGURLS 1 - Computer -Generated Body Lines . .. .. ... . . . . ... 29 2 - Exa•aple of the

  17. Design and implementation of a two-axis micromanipulator to enhance the gripper positional accuracy of a single flexible link

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoying

    1994-05-01

    Accurate and versatile robots are required to perform advanced assembly and manufacturing tasks. To improve the end effector positional accuracy of lightweight robot arms, a two-axis micro-manipulator is mounted between the robot wrist and its manipulator. The rationale is to reduce the wrist sensitivity to the structural deflections of the robotic manipulator. In an attempt to separate the problem of the end-of-arm deflections from the overall control problem of multi-link systems, the micromanipulator is tested on a single flexible link. A laser head with a dual axis photodetector is used to provide direct measurements of the transverse deflections at the free-end of the beam and to detect mechanical inaccuracies caused by manufacturing imperfections and assembly misalignment. The advantages of the integrated system of the micro-manipulator with a single compliant beam are demonstrated and compared to the one without the micro-manipulator for two different control schemes, 'rigid body controller (RBC)' and 'rigid and flexible motion controller (RFMC)' . Both theoretical and experimental results have proven the capability of the micro-manipulator in significantly improving the gripper positional accuracy. Furthermore, it was demonstrated that the micromanipulator tends to complement rather than overlap the effort exerted by the host beam controller. The experimental results have revealed the significant adverse effects of the backlash in gearing on the overall performance of the macro- and micro-manipulators. To address this problem, the dynamic model of the macro- and micro-manipulators is modified to include the dynamics of joint actuators along with the effects of backlash in the indirect drive mechanism of the compliant beam. A general method is developed to handle the dynamic characteristics of backlash in gearing. It entails the derivation of a variable structure model with one auxiliary degree-of-freedom. The latter serves to increase the number of degrees

  18. Criterion validity and accuracy of global positioning satellite and data logging devices for wheelchair tennis court movement

    PubMed Central

    Sindall, Paul; Lenton, John P.; Whytock, Katie; Tolfrey, Keith; Oyster, Michelle L.; Cooper, Rory A.; Goosey-Tolfrey, Victoria L.

    2013-01-01

    Purpose To compare the criterion validity and accuracy of a 1 Hz non-differential global positioning system (GPS) and data logger device (DL) for the measurement of wheelchair tennis court movement variables. Methods Initial validation of the DL device was performed. GPS and DL were fitted to the wheelchair and used to record distance (m) and speed (m/second) during (a) tennis field (b) linear track, and (c) match-play test scenarios. Fifteen participants were monitored at the Wheelchair British Tennis Open. Results Data logging validation showed underestimations for distance in right (DLR) and left (DLL) logging devices at speeds >2.5 m/second. In tennis-field tests, GPS underestimated distance in five drills. DLL was lower than both (a) criterion and (b) DLR in drills moving forward. Reversing drill direction showed that DLR was lower than (a) criterion and (b) DLL. GPS values for distance and average speed for match play were significantly lower than equivalent values obtained by DL (distance: 2816 (844) vs. 3952 (1109) m, P = 0.0001; average speed: 0.7 (0.2) vs. 1.0 (0.2) m/second, P = 0.0001). Higher peak speeds were observed in DL (3.4 (0.4) vs. 3.1 (0.5) m/second, P = 0.004) during tennis match play. Conclusions Sampling frequencies of 1 Hz are too low to accurately measure distance and speed during wheelchair tennis. GPS units with a higher sampling rate should be advocated in further studies. Modifications to existing DL devices may be required to increase measurement precision. Further research into the validity of movement devices during match play will further inform the demands and movement patterns associated with wheelchair tennis. PMID:23820154

  19. Positional Accuracy Assessment of the Openstreetmap Buildings Layer Through Automatic Homologous Pairs Detection: the Method and a Case Study

    NASA Astrophysics Data System (ADS)

    Brovelli, M. A.; Minghini, M.; Molinari, M. E.; Zamboni, G.

    2016-06-01

    OpenStreetMap (OSM) is currently the largest openly licensed collection of geospatial data. Being OSM increasingly exploited in a variety of applications, research has placed great attention on the assessment of its quality. This work focuses on assessing the quality of OSM buildings. While most of the studies available in literature are limited to the evaluation of OSM building completeness, this work proposes an original approach to assess the positional accuracy of OSM buildings based on comparison with a reference dataset. The comparison relies on a quasi-automated detection of homologous pairs on the two datasets. Based on the homologous pairs found, warping algorithms like e.g. affine transformations and multi-resolution splines can be applied to the OSM buildings to generate a new version having an optimal local match to the reference layer. A quality assessment of the OSM buildings of Milan Municipality (Northern Italy), having an area of about 180 km2, is then presented. After computing some measures of completeness, the algorithm based on homologous points is run using the building layer of the official vector cartography of Milan Municipality as the reference dataset. Approximately 100000 homologous points are found, which show a systematic translation of about 0.4 m on both the X and Y directions and a mean distance of about 0.8 m between the datasets. Besides its efficiency and high degree of automation, the algorithm generates a warped version of OSM buildings which, having by definition a closest match to the reference buildings, can be eventually integrated in the OSM database.

  20. Accuracy of MRI for prediction of response to neo-adjuvant chemotherapy in triple negative breast cancer compared to other subtypes of breast cancer

    PubMed Central

    Bansal, Gaurav J; Santosh, Divya

    2016-01-01

    Purpose: The aim of this study was to compare the accuracy of magnetic resonance imaging (MRI) for the prediction of response to neo-adjuvant chemotherapy in triple negative (TN) breast cancer, with respect to other subtypes. Materials and Methods: There were a total of 1610 breast cancers diagnosed between March 2009 and August 2014, out of which 82 patients underwent MRI before and after neo-adjuvant chemotherapy but just before surgery. TN cancers were analyzed with respect to others subtypes. Accuracy of MRI for prediction of pathological complete response was compared between different subtypes by obtaining receiver operating characteristic (ROC) curves. The Statistical Package for the Social Sciences version 21 was used for all data analysis, with P value of 0.05 as statistically significant. Results: Out of 82 patients, 29 were luminal (HR+/HER2−), 23 were TN (HR−, HER2−), 11 were HER2 positive (HR−, HER2+), and 19 were of hybrid subtype (HR+/HER2+). TN cancers presented as masses on the pre-chemotherapy MRI scan, were grade 3 on histopathology, and showed concentric shrinkage following chemotherapy. TN cancers were more likely to have both imaging and pathological complete response following chemotherapy (P = 0.055) in contrast to luminal cancers, which show residual cancer. ROC curves were constructed for the prediction of pathological complete response with MRI. For the TN subgroup, MR had a sensitivity of 0.745 and specificity of 0.700 (P = 0.035), with an area under curve of 0.745 (95% confidence interval: 0.526–0.965), which was significantly better compared to other subtypes. Conclusion: TN breast cancers present as masses and show concentric shrinkage following chemotherapy. MRI is most accurate in predicting response to chemotherapy in the TN group, compared to others subtypes. MRI underestimates residual disease in luminal cancers. PMID:28104942

  1. Visual Discrimination Predicts Naming and Semantic Association Accuracy in Alzheimer’s Disease

    PubMed Central

    Harnish, Stacy M.; Neils-Strunjas, Jean; Eliassen, James; Reilly, Jamie; Meinzer, Marcus; Clark, John Greer; Joseph, Jane

    2010-01-01

    Objective Language impairment is a common symptom of Alzheimer’s disease (AD) and is thought to be related to semantic processing. The present study examines the contribution of another process, namely visual perception, on measures of confrontation naming and semantic association abilities in persons with probable AD. Methods Twenty individuals with probable mild-moderate Alzheimer’s disease and twenty age-matched controls completed a battery of neuropsychological measures assessing visual perception, naming, and semantic association ability. Visual discrimination tasks that varied in the degree to which they likely accessed stored structural representations were used to gauge whether structural processing deficits could account for deficits in naming and in semantic association in AD. Results Visual discrimination abilities of nameable objects in AD strongly predicted performance on both picture naming and semantic association ability but lacked the same predictive value for controls. Although impaired, performance on visual discrimination tests of abstract shapes and novel faces showed no significant relationship with picture naming and semantic association. These results provide additional evidence to support that structural processing deficits exist in AD and may contribute to object recognition and naming deficits. Conclusions Our findings suggest that there is a common deficit in discrimination of pictures using nameable objects, picture naming and semantic association of pictures in AD. Disturbances in structural processing of pictured items may be associated with lexical-semantic impairment in AD due to degraded internal storage of structural knowledge. PMID:21042208

  2. Evaluating the accuracy of recent electron transport models at predicting Hall thruster plasma dynamics

    NASA Astrophysics Data System (ADS)

    Cappelli, Mark; Young, Christopher

    2016-10-01

    We present continued efforts towards introducing physical models for cross-magnetic field electron transport into Hall thruster discharge simulations. In particular, we seek to evaluate whether such models accurately capture ion dynamics, both averaged and resolved in time, through comparisons with measured ion velocity distributions which are now becoming available for several devices. Here, we describe a turbulent electron transport model that is integrated into 2-D hybrid fluid/PIC simulations of a 72 mm diameter laboratory thruster operating at 400 W. We also compare this model's predictions with one recently proposed by Lafluer et al.. Introducing these models into 2-D hybrid simulations is relatively straightforward and leverages the existing framework for solving the electron fluid equations. The models are tested for their ability to capture the time-averaged experimental discharge current and its fluctuations due to ionization instabilities. Model predictions are also more rigorously evaluated against recent laser-induced fluorescence measurements of time-resolved ion velocity distributions.

  3. BEYOND THE MAIN SEQUENCE: TESTING THE ACCURACY OF STELLAR MASSES PREDICTED BY THE PARSEC EVOLUTIONARY TRACKS

    SciTech Connect

    Ghezzi, Luan; Johnson, John Asher

    2015-10-20

    Characterizing the physical properties of exoplanets and understanding their formation and orbital evolution requires precise and accurate knowledge of their host stars. Accurately measuring stellar masses is particularly important because they likely influence planet occurrence and the architectures of planetary systems. Single main-sequence stars typically have masses estimated from evolutionary tracks, which generally provide accurate results due to their extensive empirical calibration. However, the validity of this method for subgiants and giants has been called into question by recent studies, with suggestions that the masses of these evolved stars could have been overestimated. We investigate these concerns using a sample of 59 benchmark evolved stars with model-independent masses (from binary systems or asteroseismology) obtained from the literature. We find very good agreement between these benchmark masses and the ones estimated using evolutionary tracks. The average fractional difference in the mass interval ∼0.7–4.5 M{sub ⊙} is consistent with zero (−1.30 ± 2.42%), with no significant trends in the residuals relative to the input parameters. A good agreement between model-dependent and -independent radii (−4.81 ± 1.32%) and surface gravities (0.71 ± 0.51%) is also found. The consistency between independently determined ages for members of binary systems adds further support for the accuracy of the method employed to derive the stellar masses. Taken together, our results indicate that determination of masses of evolved stars using grids of evolutionary tracks is not significantly affected by systematic errors, and is thus valid for estimating the masses of isolated stars beyond the main sequence.

  4. Increasing shape modelling accuracy by adjusting for subject positioning: an application to the analysis of radiographic proximal femur symmetry using data from the Osteoarthritis Initiative.

    PubMed

    Lindner, C; Wallis, G A; Cootes, T F

    2014-04-01

    ) adjusting for subject positioning increases the accuracy of predicting the shape of the contra-lateral hip.

  5. EEG activity during movement planning encodes upcoming peak speed and acceleration and improves the accuracy in predicting hand kinematics.

    PubMed

    Yang, Lingling; Leung, Howard; Plank, Markus; Snider, Joe; Poizner, Howard

    2015-01-01

    The relationship between movement kinematics and human brain activity is an important and fundamental question for the development of neural prosthesis. The peak velocity and the peak acceleration could best reflect the feedforward-type movement; thus, it is worthwhile to investigate them further. Most related studies focused on the correlation between kinematics and brain activity during the movement execution or imagery. However, human movement is the result of the motor planning phase as well as the execution phase and researchers have demonstrated that statistical correlations exist between EEG activity during the motor planning and the peak velocity and the peak acceleration using grand-average analysis. In this paper, we examined whether the correlations were concealed in trial-to-trial decoding from the low signal-to-noise ratio of EEG activity. The alpha and beta powers from the movement planning phase were combined with the alpha and beta powers from the movement execution phase to predict the peak tangential speed and acceleration. The results showed that EEG activity from the motor planning phase could also predict the peak speed and the peak acceleration with a reasonable accuracy. Furthermore, the decoding accuracy of the peak speed and the peak acceleration could both be improved by combining band powers from the motor planning phase with the band powers from the movement execution.

  6. Serum midkine as a surrogate biomarker for metastatic prediction in differentiated thyroid cancer patients with positive thyroglobulin antibody

    PubMed Central

    Jia, Qiang; Meng, Zhaowei; Xu, Ke; He, Xianghui; Tan, Jian; Zhang, Guizhi; Li, Xue; Liu, Na; Hu, Tianpeng; Zhou, Pingping; Wang, Sen; Upadhyaya, Arun; Liu, Xiaoxia; Wang, Huiying; Zhang, Chunmei

    2017-01-01

    Serum thyroglobulin (Tg) is the main post-operative tumor biomarker for patients with differentiated thyroid cancer (DTC). However, the presence of thyroglobulin antibodies (TgAb) can interfere with Tg level and invalidate the test. In this study, we aimed to investigate the predicative value of midkine (MK) as a cancer biomarker for DTC patients with positive TgAb before the first 131I therapy. MK levels were measured by enzyme-linked immunosorbent assay in 151 recruited DTC patients after exercising strict inclusion and exclusion criteria. There were 28 TgAb positive DTC patients with metastases and 123 DTC patients without metastases. The value of pre-131I-ablative MK to predict metastasis was assessed by receiver operating characteristic (ROC) curves in these two groups of patients. MK levels in the TgAb positive DTC patients were significantly higher than the DTC patients without metastases. ROC showed good predictability of MK, with an area under the curve of 0.856 (P < 0.001), and a diagnostic accuracy of 83% at the optimal cut-off value of 550 pg/ml. In conclusion, we show that MK can potentially be used as a surrogate biomarker for predicting DTC metastases when Tg is not suitable due to TgAb positivity. PMID:28240744

  7. Accuracy of Inferior Vena Cava Ultrasound for Predicting Dehydration in Children with Acute Diarrhea in Resource-Limited Settings

    PubMed Central

    Modi, Payal; Glavis-Bloom, Justin; Nasrin, Sabiha; Guy, Allysia; Rege, Soham; Noble, Vicki E.; Alam, Nur H.; Levine, Adam C.

    2016-01-01

    Introduction Although dehydration from diarrhea is a leading cause of morbidity and mortality in children under five, existing methods of assessing dehydration status in children have limited accuracy. Objective To assess the accuracy of point-of-care ultrasound measurement of the aorta-to-IVC ratio as a predictor of dehydration in children. Methods A prospective cohort study of children under five years with acute diarrhea was conducted in the rehydration unit of the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b). Ultrasound measurements of aorta-to-IVC ratio and dehydrated weight were obtained on patient arrival. Percent weight change was monitored during rehydration to classify children as having “some dehydration” with weight change 3–9% or “severe dehydration” with weight change > 9%. Logistic regression analysis and Receiver-Operator Characteristic (ROC) curves were used to evaluate the accuracy of aorta-to-IVC ratio as a predictor of dehydration severity. Results 850 children were enrolled, of which 771 were included in the final analysis. Aorta to IVC ratio was a significant predictor of the percent dehydration in children with acute diarrhea, with each 1-point increase in the aorta to IVC ratio predicting a 1.1% increase in the percent dehydration of the child. However, the area under the ROC curve (0.60), sensitivity (67%), and specificity (49%), for predicting severe dehydration were all poor. Conclusions Point-of-care ultrasound of the aorta-to-IVC ratio was statistically associated with volume status, but was not accurate enough to be used as an independent screening tool for dehydration in children under five years presenting with acute diarrhea in a resource-limited setting. PMID:26766306

  8. Positive predictive values of abused drug immunoassays on the Beckman Synchron in a veteran population.

    PubMed

    Dietzen, D J; Ecos, K; Friedman, D; Beason, S

    2001-04-01

    The pressure to reduce the cost of analytic testing makes it tempting to discontinue routine confirmation of urine specimens positive for drugs of abuse by immunoassay. Beyond the economic motivation, the requirement for confirmation should be driven by the positive predictive value of the screening tests. We have quantitated positive predictive values of our screening immunoassays in a large metropolitan Veterans Affairs Medical Center. We reviewed the confirmatory rate of urine specimens positive for drugs of abuse with Beckman Synchron reagents from June 1998 to June 1999 and tabulated the false-positive screening rate. There were 175 instances of false-positive screens during the 13 months we analyzed. Positive predictive values ranged from 0% (amphetamine) to 100% (THC). We determined that the low positive predictive value of the amphetamine assay in our laboratory was primarily due to the use of ranitidine (Zantac). Urine specimens containing greater than 43 microg/mL ranitidine were positive in our amphetamine assay. This concentration is routinely exceeded in our patients taking ranitidine. In our clinical and analytic setting, the Beckman THC assay did not require confirmation. The positive predictive values of the Beckman opiate, cocaine, barbiturate, propoxyphene, and methadone immunoassays dictate routine confirmatory testing in specimens that screen positive for these substances. Finally, because of its extreme sensitivity to ranitidine, the Beckman amphetamine assay has little utility in our laboratory setting.

  9. Accuracy of the actuator disc-RANS approach for predicting the performance and wake of tidal turbines.

    PubMed

    Batten, W M J; Harrison, M E; Bahaj, A S

    2013-02-28

    The actuator disc-RANS model has widely been used in wind and tidal energy to predict the wake of a horizontal axis turbine. The model is appropriate where large-scale effects of the turbine on a flow are of interest, for example, when considering environmental impacts, or arrays of devices. The accuracy of the model for modelling the wake of tidal stream turbines has not been demonstrated, and flow predictions presented in the literature for similar modelled scenarios vary significantly. This paper compares the results of the actuator disc-RANS model, where the turbine forces have been derived using a blade-element approach, to experimental data measured in the wake of a scaled turbine. It also compares the results with those of a simpler uniform actuator disc model. The comparisons show that the model is accurate and can predict up to 94 per cent of the variation in the experimental velocity data measured on the centreline of the wake, therefore demonstrating that the actuator disc-RANS model is an accurate approach for modelling a turbine wake, and a conservative approach to predict performance and loads. It can therefore be applied to similar scenarios with confidence.

  10. Assessing genomic prediction accuracy for Holstein sires using bootstrap aggregation sampling and leave-one-out cross validation.

    PubMed

    Mikshowsky, Ashley A; Gianola, Daniel; Weigel, Kent A

    2017-01-01

    Since the introduction of genome-enabled prediction for dairy cattle in 2009, genomic selection has markedly changed many aspects of the dairy genetics industry and enhanced the rate of response to selection for most economically important traits. Young dairy bulls are genotyped to obtain their genomic predicted transmitting ability (GPTA) and reliability (REL) values. These GPTA are a main factor in most purchasing, marketing, and culling decisions until bulls reach 5 yr of age and their milk-recorded offspring become available. At that time, daughter yield deviations (DYD) can be compared with the GPTA computed several years earlier. For most bulls, the DYD align well with the initial predictions. However, for some bulls, the difference between DYD and corresponding GPTA is quite large, and published REL are of limited value in identifying such bulls. A method of bootstrap aggregation sampling (bagging) using genomic BLUP (GBLUP) was applied to predict the GPTA of 2,963, 2,963, and 2,803 young Holstein bulls for protein yield, somatic cell score, and daughter pregnancy rate (DPR), respectively. For each trait, 50 bootstrap samples from a reference population comprising 2011 DYD of 8,610, 8,405, and 7,945 older Holstein bulls were used. Leave-one-out cross validation was also performed to assess prediction accuracy when removing specific bulls from the reference population. The main objectives of this study were (1) to assess the extent to which current REL values and alternative measures of variability, such as the bootstrap standard deviation (SD) of predictions, could detect bulls whose daughter performance deviates significantly from early genomic predictions, and (2) to identify factors associated with the reference population that inform about inaccurate genomic predictions. The SD of bootstrap predictions was a mildly useful metric for identifying bulls whose future daughter performance may deviate significantly from early GPTA for protein and DPR. Leave

  11. Effect of Over-Tree Evaporative Cooling in Orchards on Microclimate and Accuracy of Insect Model Predictions.

    PubMed

    Chambers, Ute; Jones, Vincent P

    2015-12-01

    Orchard design and management practices can alter microclimate and, thus, potentially affect insect development. If sufficiently large, these deviations in microclimate can compromise the accuracy of phenology model predictions used in integrated pest management (IPM) programs. Sunburn causes considerable damage in the Pacific Northwest, United States, apple-producing region. Common prevention strategies include the use of fruit surface protectants, evaporative cooling (EC), or both. This study focused on the effect of EC on ambient temperatures and model predictions for four insects (codling moth, Cydia pomonella L.; Lacanobia fruitworm, Lacanobia subjuncta Grote and Robinson; oblique-banded leafroller, Choristoneura rosaceana Harris; and Pandemis leafroller, Pandemis pyrusana Kearfott). Over-tree EC was applied in July and August when daily maximum temperatures were predicted to be ≥30°C between 1200-1700 hours (15/15 min on/off interval) in 2011 and between 1200-1800 hours (15/10 min on/off interval, or continuous on) in 2012. Control plots were sprayed once with kaolin clay in early July. During interval and continuous cooling, over-tree cooling reduced average afternoon temperatures compared with the kaolin treatment by 2.1-3.2°C. Compared with kaolin-treated controls, codling moth and Lacanobia fruitworm egg hatch in EC plots was predicted to occur up to 2 d and 1 d late, respectively. The presence of fourth-instar oblique-banded leafroller and Pandemis leafroller was predicted to occur up to 2 d and 1 d earlier in EC plots, respectively. These differences in model predictions were negligible, suggesting that no adjustments in pest management timing are needed when using EC in high-density apple orchards.

  12. Accuracy of sea level predictions with lead time of one week: a comparison between Prognocean and MyOcean

    NASA Astrophysics Data System (ADS)

    Swierczynska, Malgorzata; Mizinski, Bartlomiej; Niedzielski, Tomasz

    2015-04-01

    There exist several systems which produce sea level forecasts in real time, with lead times ranging from hours to two weeks in the future. One of the recently developed solutions is Prognocean, the system that has been built and implemented at the University of Wroclaw, Poland. Its main feature is that it uses simple time series models to predict sea level anomaly maps, and does it for lead times ranging from 1 to 14 days with daily update. The empirical data-based models are fitted in real time both to individual grids (polynomial-harmonic model, polynomial-harmonic model combined with autoregressive model, polynomial-harmonic model combined with threshold autoregressive model) and to numerous grids forming a spatial latitude x longitude window of 3˚ x 5˚ (polynomial-harmonic model combined with multivariate autoregressive model). Although their simplicity, the approaches have already been shown to produce sea level anomaly predictions of reasonable accuracy. However, none of the analyses targeted at the comparative study which would present the skills of the Prognocean system against a background of the performance of other systems that use physically-based models. This study aims to fill this gap by comparing Prognocean-based predictions for one week into the future with the corresponding prognoses calculated by MyOcean. The reader is provided with the objectively-calculated set of statistics, presented as maps, which describes prediction errors (mean absolute error, root mean square error, index of agreement) and prediction skills (prediction efficiency, coefficient of determination) of the two systems. The exercise enables to compare the skills of the approaches, and the gridwise comparison allows one to identify areas of superior performance of each system.

  13. Translation of Land Surface Model Accuracy and Uncertainty into Coupled Land-Atmosphere Prediction

    NASA Technical Reports Server (NTRS)

    Santanello, Joseph A.; Kumar, Sujay; Peters-Lidard, Christa D.; Harrison, Kenneth W.; Zhou, Shuija

    2012-01-01

    Land-atmosphere (L-A) Interactions playa critical role in determining the diurnal evolution of both planetary boundary layer (PBL) and land surface heat and moisture budgets, as well as controlling feedbacks with clouds and precipitation that lead to the persistence of dry and wet regimes. Recent efforts to quantify the strength of L-A coupling in prediction models have produced diagnostics that integrate across both the land and PBL components of the system. In this study, we examine the impact of improved specification of land surface states, anomalies, and fluxes on coupled WRF forecasts during the summers of extreme dry (2006) and wet (2007) land surface conditions in the U.S. Southern Great Plains. The improved land initialization and surface flux parameterizations are obtained through the use of a new optimization and uncertainty estimation module in NASA's Land Information System (US-OPT/UE), whereby parameter sets are calibrated in the Noah land surface model and classified according to a land cover and soil type mapping of the observation sites to the full model domain. The impact of calibrated parameters on the a) spinup of the land surface used as initial conditions, and b) heat and moisture states and fluxes of the coupled WRF Simulations are then assessed in terms of ambient weather and land-atmosphere coupling along with measures of uncertainty propagation into the forecasts. In addition, the sensitivity of this approach to the period of calibration (dry, wet, average) is investigated. Finally, tradeoffs of computational tractability and scientific validity, and the potential for combining this approach with satellite remote sensing data are also discussed.

  14. Smart Device-Supported BDS/GNSS Real-Time Kinematic Positioning for Sub-Meter-Level Accuracy in Urban Location-Based Services

    PubMed Central

    Wang, Liang; Li, Zishen; Zhao, Jiaojiao; Zhou, Kai; Wang, Zhiyu; Yuan, Hong

    2016-01-01

    Using mobile smart devices to provide urban location-based services (LBS) with sub-meter-level accuracy (around 0.5 m) is a major application field for future global navigation satellite system (GNSS) development. Real-time kinematic (RTK) positioning, which is a widely used GNSS-based positioning approach, can improve the accuracy from about 10–20 m (achieved by the standard positioning services) to about 3–5 cm based on the geodetic receivers. In using the smart devices to achieve positioning with sub-meter-level accuracy, a feasible solution of combining the low-cost GNSS module and the smart device is proposed in this work and a user-side GNSS RTK positioning software was developed from scratch based on the Android platform. Its real-time positioning performance was validated by BeiDou Navigation Satellite System/Global Positioning System (BDS/GPS) combined RTK positioning under the conditions of a static and kinematic (the velocity of the rover was 50–80 km/h) mode in a real urban environment with a SAMSUNG Galaxy A7 smartphone. The results show that the fixed-rates of ambiguity resolution (the proportion of epochs of ambiguities fixed) for BDS/GPS combined RTK in the static and kinematic tests were about 97% and 90%, respectively, and the average positioning accuracies (RMS) were better than 0.15 m (horizontal) and 0.25 m (vertical) for the static test, and 0.30 m (horizontal) and 0.45 m (vertical) for the kinematic test. PMID:28009835

  15. Smart Device-Supported BDS/GNSS Real-Time Kinematic Positioning for Sub-Meter-Level Accuracy in Urban Location-Based Services.

    PubMed

    Wang, Liang; Li, Zishen; Zhao, Jiaojiao; Zhou, Kai; Wang, Zhiyu; Yuan, Hong

    2016-12-21

    Using mobile smart devices to provide urban location-based services (LBS) with sub-meter-level accuracy (around 0.5 m) is a major application field for future global navigation satellite system (GNSS) development. Real-time kinematic (RTK) positioning, which is a widely used GNSS-based positioning approach, can improve the accuracy from about 10-20 m (achieved by the standard positioning services) to about 3-5 cm based on the geodetic receivers. In using the smart devices to achieve positioning with sub-meter-level accuracy, a feasible solution of combining the low-cost GNSS module and the smart device is proposed in this work and a user-side GNSS RTK positioning software was developed from scratch based on the Android platform. Its real-time positioning performance was validated by BeiDou Navigation Satellite System/Global Positioning System (BDS/GPS) combined RTK positioning under the conditions of a static and kinematic (the velocity of the rover was 50-80 km/h) mode in a real urban environment with a SAMSUNG Galaxy A7 smartphone. The results show that the fixed-rates of ambiguity resolution (the proportion of epochs of ambiguities fixed) for BDS/GPS combined RTK in the static and kinematic tests were about 97% and 90%, respectively, and the average positioning accuracies (RMS) were better than 0.15 m (horizontal) and 0.25 m (vertical) for the static test, and 0.30 m (horizontal) and 0.45 m (vertical) for the kinematic test.

  16. Prediction and compensation of magnetic beam deflection in MR-integrated proton therapy: a method optimized regarding accuracy, versatility and speed.

    PubMed

    Schellhammer, Sonja M; Hoffmann, Aswin L

    2017-02-21

    The integration of magnetic resonance imaging (MRI) and proton therapy for on-line image-guidance is expected to reduce dose delivery uncertainties during treatment. Yet, the proton beam experiences a Lorentz force induced deflection inside the magnetic field of the MRI scanner, and several methods have been proposed to quantify this effect. We analyze their structural differences and compare results of both analytical and Monte Carlo models. We find that existing analytical models are limited in accuracy and applicability due to critical approximations, especially including the assumption of a uniform magnetic field. As Monte Carlo simulations are too time-consuming for routine treatment planning and on-line plan adaption, we introduce a new method to quantify and correct for the beam deflection, which is optimized regarding accuracy, versatility and speed. We use it to predict the trajectory of a mono-energetic proton beam of energy E 0 traversing a water phantom behind an air gap within an omnipresent uniform transverse magnetic flux density B 0. The magnetic field induced dislocation of the Bragg peak is calculated as function of E 0 and B 0 and compared to results obtained with existing analytical and Monte Carlo methods. The deviation from the Bragg peak position predicted by Monte Carlo simulations is smaller for the new model than for the analytical models by up to 2 cm. The model is faster than Monte Carlo methods, less assumptive than the analytical models and applicable to realistic magnetic fields. To compensate for the predicted Bragg peak dislocation, a numerical optimization strategy is introduced and evaluated. It includes an adjustment of both the proton beam entrance angle and energy of up to 25° and 5 MeV, depending on E 0 and B 0. This strategy is shown to effectively reposition the Bragg peak to its intended location in the presence of a magnetic field.

  17. Prediction and compensation of magnetic beam deflection in MR-integrated proton therapy: a method optimized regarding accuracy, versatility and speed

    NASA Astrophysics Data System (ADS)

    Schellhammer, Sonja M.; Hoffmann, Aswin L.

    2017-02-01

    The integration of magnetic resonance imaging (MRI) and proton therapy for on-line image-guidance is expected to reduce dose delivery uncertainties during treatment. Yet, the proton beam experiences a Lorentz force induced deflection inside the magnetic field of the MRI scanner, and several methods have been proposed to quantify this effect. We analyze their structural differences and compare results of both analytical and Monte Carlo models. We find that existing analytical models are limited in accuracy and applicability due to critical approximations, especially including the assumption of a uniform magnetic field. As Monte Carlo simulations are too time-consuming for routine treatment planning and on-line plan adaption, we introduce a new method to quantify and correct for the beam deflection, which is optimized regarding accuracy, versatility and speed. We use it to predict the trajectory of a mono-energetic proton beam of energy E 0 traversing a water phantom behind an air gap within an omnipresent uniform transverse magnetic flux density B 0. The magnetic field induced dislocation of the Bragg peak is calculated as function of E 0 and B 0 and compared to results obtained with existing analytical and Monte Carlo methods. The deviation from the Bragg peak position predicted by Monte Carlo simulations is smaller for the new model than for the analytical models by up to 2 cm. The model is faster than Monte Carlo methods, less assumptive than the analytical models and applicable to realistic magnetic fields. To compensate for the predicted Bragg peak dislocation, a numerical optimization strategy is introduced and evaluated. It includes an adjustment of both the proton beam entrance angle and energy of up to 25° and 5 MeV, depending on E 0 and B 0. This strategy is shown to effectively reposition the Bragg peak to its intended location in the presence of a magnetic field.

  18. Positive teacher and peer relations combine to predict primary school students' academic skill development.

    PubMed

    Kiuru, Noona; Aunola, Kaisa; Lerkkanen, Marja-Kristiina; Pakarinen, Eija; Poskiparta, Elisa; Ahonen, Timo; Poikkeus, Anna-Maija; Nurmi, Jari-Erik

    2015-04-01

    This study examined cross-lagged associations between positive teacher and peer relations and academic skill development. Reading and math skills were tested among 625 students in kindergarten and Grade 4. Teacher reports of positive affect toward each student and classmate reports of peer acceptance were gathered in Grades 1-3. The results showed, first, that positive teacher affect toward the student and peer acceptance were reciprocally associated: Positive teacher affect predicted higher peer acceptance, and higher peer acceptance predicted a higher level of positive teacher affect. Second, the effect of positive teacher affect on academic skill development was partly mediated via peer acceptance, while the effect of early academic skills on peer acceptance was partly mediated via positive teacher affect. The results suggest that a warm and supportive teacher can increase a student's peer acceptance, which, in turn, is positively associated with learning outcomes.

  19. Accuracy of color prediction of anthraquinone dyes in methanol solution estimated from first principle quantum chemistry computations.

    PubMed

    Cysewski, Piotr; Jeliński, Tomasz

    2013-10-01

    The electronic spectrum of four different anthraquinones (1,2-dihydroxyanthraquinone, 1-aminoanthraquinone, 2-aminoanthraquinone and 1-amino-2-methylanthraquinone) in methanol solution was measured and used as reference data for theoretical color prediction. The visible part of the spectrum was modeled according to TD-DFT framework with a broad range of DFT functionals. The convoluted theoretical spectra were validated against experimental data by a direct color comparison in terms of CIE XYZ and CIE Lab tristimulus model color. It was found, that the 6-31G** basis set provides the most accurate color prediction and there is no need to extend the basis set since it does not improve the prediction of color. Although different functionals were found to give the most accurate color prediction for different anthraquinones, it is possible to apply the same DFT approach for the whole set of analyzed dyes. Especially three functionals seem to be valuable, namely mPW1LYP, B1LYP and PBE0 due to very similar spectra predictions. The major source of discrepancies between theoretical and experimental spectra comes from L values, representing the lightness, and the a parameter, depicting the position on green→magenta axis. Fortunately, the agreement between computed and observed blue→yellow axis (parameter b) is very precise in the case of studied anthraquinone dyes in methanol solution. Despite discussed shortcomings, color prediction from first principle quantum chemistry computations can lead to quite satisfactory results, expressed in terms of color space parameters.

  20. Pleasure Now, Pain Later: Positive Fantasies About the Future Predict Symptoms of Depression.

    PubMed

    Oettingen, Gabriele; Mayer, Doris; Portnow, Sam

    2016-03-01

    Though common sense suggests that positive thinking shelters people from depression, the four studies reported here showed that this intuition needs to be qualified: Positive thinking in the form of fantasies about the future did indeed relate to decreased symptoms of depression when measured concurrently; however, positive fantasies predicted more depressive symptoms when measured longitudinally. The pattern of results was observed for different indicators of fantasies and depression, in adults and in schoolchildren, and for periods of up to 7 months (Studies 1-4). In college students, low academic success partially mediated the predictive relation between positive fantasies and symptoms of depression (Study 4). Results add to existing research on the problematic effects of positive fantasies on performance by suggesting that indulging in positive fantasies predicts problems in mental health.

  1. Is a positive history of non-anaesthetic drug allergy a predictive factor for positive allergy tests to anaesthetics?

    PubMed Central

    Hagau, Natalia; Gherman-Ionica, Nadia; Hagau, Denisa; Tranca, Sebastian; Sfichi, Manuela; Longrois, Dan

    2012-01-01

    AIMS International recommendations stipulate not performing screening skin tests to a drug in the absence of a clinical history consistent with that specific drug allergy. Nevertheless, two publications showed that a positive history of non-anaesthetic drug allergy was the only predictive factor for a positive skin test when screening for allergy to anaesthetic drugs was done. We selected from a surgical population 40 volunteers with a prior history of allergy to non-anaesthetic drugs in order to analyse the prevalence of positive allergy tests to anaesthetics. METHODS The selected adult patients were tested for 11 anaesthetic drugs using in vivo tests: skin prick (SPT) and intradermal (IDT) tests and in vitro tests: the basophil activation test (BAT) and detection of drug-specific immunoglobulin E (IgE). RESULTS The prevalence for the positive SPT and IDT was 1.6% and 5.8% respectively. The result of flow cytometry agreed with the SPT in five out of seven positive SPT (71%). IgEs confirmed two positive SPT with corresponding positive BAT. Ten per cent of the patients had a positive prick test to neuromuscular blocking agents (NMBA). For midazolam none of the SPT was positive, but 11 patients had positive IDT nonconfirmed by BAT. CONCLUSION The prevalence of positive in vivo and in vitro allergy tests to NMBAs is higher in our study population. This could be an argument for pre-operative SPT to NMBAs for the surgical population with reported non-anaesthetic drug allergies. A larger prospective study is needed to validate changes in clinical practice. PMID:21988224

  2. The short- to medium-term predictive accuracy of static and dynamic risk assessment measures in a secure forensic hospital.

    PubMed

    Chu, Chi Meng; Thomas, Stuart D M; Ogloff, James R P; Daffern, Michael

    2013-04-01

    Although violence risk assessment knowledge and practice has advanced over the past few decades, it remains practically difficult to decide which measures clinicians should use to assess and make decisions about the violence potential of individuals on an ongoing basis, particularly in the short to medium term. Within this context, this study sought to compare the predictive accuracy of dynamic risk assessment measures for violence with static risk assessment measures over the short term (up to 1 month) and medium term (up to 6 months) in a forensic psychiatric inpatient setting. Results showed that dynamic measures were generally more accurate than static measures for short- to medium-term predictions of inpatient aggression. These findings highlight the necessity of using risk assessment measures that are sensitive to important clinical risk state variables to improve the short- to medium-term prediction of aggression within the forensic inpatient setting. Such knowledge can assist with the development of more accurate and efficient risk assessment procedures, including the selection of appropriate risk assessment instruments to manage and prevent the violence of offenders with mental illnesses during inpatient treatment.

  3. Using cross-validation to evaluate predictive accuracy of survival risk classifiers based on high-dimensional data.

    PubMed

    Simon, Richard M; Subramanian, Jyothi; Li, Ming-Chung; Menezes, Supriya

    2011-05-01

    Developments in whole genome biotechnology have stimulated statistical focus on prediction methods. We review here methodology for classifying patients into survival risk groups and for using cross-validation to evaluate such classifications. Measures of discrimination for survival risk models include separation of survival curves, time-dependent ROC curves and Harrell's concordance index. For high-dimensional data applications, however, computing these measures as re-substitution statistics on the same data used for model development results in highly biased estimates. Most developments in methodology for survival risk modeling with high-dimensional data have utilized separate test data sets for model evaluation. Cross-validation has sometimes been used for optimization of tuning parameters. In many applications, however, the data available are too limited for effective division into training and test sets and consequently authors have often either reported re-substitution statistics or analyzed their data using binary classification methods in order to utilize familiar cross-validation. In this article we have tried to indicate how to utilize cross-validation for the evaluation of survival risk models; specifically how to compute cross-validated estimates of survival distributions for predicted risk groups and how to compute cross-validated time-dependent ROC curves. We have also discussed evaluation of the statistical significance of a survival risk model and evaluation of whether high-dimensional genomic data adds predictive accuracy to a model based on standard covariates alone.

  4. Accuracy of time comparison derived from reception of LORAN-C and Global Positioning System time signals.

    NASA Astrophysics Data System (ADS)

    Horiai, K.

    1992-10-01

    The accuracy of time comparison by means of the reception of common time signals, namely, LORAN-C and GPS, is examined. Differences of UTC from the emission times of these two radio wave signals measured at four Japanese stations and one US station are analyzed and compared with the clock comparison reports published by the Bureau International des Poids et Mesures. The accuracy of the time comparison via LORAN-C signals of the northwest Pacific chain is about 3.61 μs and that via GPS is 0.14 μs.

  5. Prediction of SAMPL3 Host-Guest Binding Affinities: Evaluating the Accuracy of Generalized Force-Fields

    PubMed Central

    Muddana, Hari S.; Gilson, Michael K.

    2012-01-01

    We used the second-generation mining minima method (M2) to compute the binding affinities of the novel host-guest complexes in the SAMPL3 blind prediction challenge. The predictions were in poor agreement with experiment, and we conjectured that much of the error might derive from the force field, CHARMm with Vcharge charges. Repeating the calculations with other generalized force-fields led to no significant improvement, and we observed that the predicted affinities were highly sensitive to the choice of force-field. We therefore embarked on a systematic evaluation of a set of generalized force fields, based upon comparisons with PM6-DH2, a fast yet accurate semi-empirical quantum mechanics method. In particular, we compared gas-phase interaction energies and entropies for the host-guest complexes themselves, as well as for smaller chemical fragments derived from the same molecules. The mean deviations of the force field interaction energies from the quantum results were greater than 3 kcal/mol and 9 kcal/mol, for the fragments and host-guest systems respectively. We further evaluated the accuracy of force-fields for computing the vibrational entropies and found the mean errors to be greater than 4 kcal/mol. Given these errors in energy and entropy, it is not surprising in retrospect that the predicted binding affinities deviated from the experiment by several kcal/mol. These results emphasize the need for improvements in generalized force-fields and also highlight the importance of systematic evaluation of force-field parameters prior to evaluating different free-energy methods. PMID:22274835

  6. Diagnostic accuracy of calculated serum osmolarity to predict dehydration in older people: adding value to pathology laboratory reports

    PubMed Central

    Hooper, Lee; Abdelhamid, Asmaa; Ali, Adam; Bunn, Diane K; Jennings, Amy; John, W Garry; Kerry, Susan; Lindner, Gregor; Pfortmueller, Carmen A; Sjöstrand, Fredrik; Walsh, Neil P; Fairweather-Tait, Susan J; Potter, John F; Hunter, Paul R; Shepstone, Lee

    2015-01-01

    Objectives To assess which osmolarity equation best predicts directly measured serum/plasma osmolality and whether its use could add value to routine blood test results through screening for dehydration in older people. Design Diagnostic accuracy study. Participants Older people (≥65 years) in 5 cohorts: Dietary Strategies for Healthy Ageing in Europe (NU-AGE, living in the community), Dehydration Recognition In our Elders (DRIE, living in residential care), Fortes (admitted to acute medical care), Sjöstrand (emergency room) or Pfortmueller cohorts (hospitalised with liver cirrhosis). Reference standard for hydration status Directly measured serum/plasma osmolality: current dehydration (serum osmolality >300 mOsm/kg), impending/current dehydration (≥295 mOsm/kg). Index tests 39 osmolarity equations calculated using serum indices from the same blood draw as directly measured osmolality. Results Across 5 cohorts 595 older people were included, of whom 19% were dehydrated (directly measured osmolality >300 mOsm/kg). Of 39 osmolarity equations, 5 showed reasonable agreement with directly measured osmolality and 3 had good predictive accuracy in subgroups with diabetes and poor renal function. Two equations were characterised by narrower limits of agreement, low levels of differential bias and good diagnostic accuracy in receiver operating characteristic plots (areas under the curve >0.8). The best equation was osmolarity=1.86×(Na++ K+)+1.15×glucose+urea+14 (all measured in mmol/L). It appeared useful in people aged ≥65 years with and without diabetes, poor renal function, dehydration, in men and women, with a range of ages, health, cognitive and functional status. Conclusions Some commonly used osmolarity equations work poorly, and should not be used. Given costs and prevalence of dehydration in older people we suggest use of the best formula by pathology laboratories using a cutpoint of 295 mOsm/L (sensitivity 85%, specificity 59%), to report

  7. Model predictions and observed performance of JWST's cryogenic position metrology system

    NASA Astrophysics Data System (ADS)

    Lunt, Sharon R.; Rhodes, David; DiAntonio, Andrew; Boland, John; Wells, Conrad; Gigliotti, Trevis; Johanning, Gary

    2016-07-01

    The James Webb Space Telescope (JWST) cryogenic testing requires measurement systems that both obtain a very high degree of accuracy and can function in that environment. Close-range photogrammetry was identified as meeting those criteria. Testing the capability of a close-range photogrammetric system prior to its existence is a challenging problem. Computer simulation was chosen over building a scaled mock-up to allow for increased flexibility in testing various configurations. Extensive validation work was done to ensure that the actual as-built system meets accuracy and repeatability requirements. The simulated image data predicted the uncertainty in measurement to be within specification and this prediction was borne out experimentally. Uncertainty at all levels was verified experimentally to be <0.1 mm.

  8. Model Predictions and Observed Performance of JWST's Cryogenic Position Metrology System

    NASA Technical Reports Server (NTRS)

    Lunt, Sharon R.; Rhodes, David; DiAntonio, Andrew; Boland, John; Wells, Conrad; Gigliotti, Trevis; Johanning, Gary

    2016-01-01

    The James Webb Space Telescope cryogenic testing requires measurement systems that both obtain a very high degree of accuracy and can function in that environment. Close-range photogrammetry was identified as meeting those criteria. Testing the capability of a close-range photogrammetric system prior to its existence is a challenging problem. Computer simulation was chosen over building a scaled mock-up to allow for increased flexibility in testing various configurations. Extensive validation work was done to ensure that the actual as-built system meet accuracy and repeatability requirements. The simulated image data predicted the uncertainty in measurement to be within specification and this prediction was borne out experimentally. Uncertainty at all levels was verified experimentally to be less than 0.1 millimeters.

  9. Accuracy and efficiency of an infrared based positioning and tracking system for patient set-up and monitoring in image guided radiotherapy

    NASA Astrophysics Data System (ADS)

    Jia, Jing; Xu, Gongming; Pei, Xi; Cao, Ruifen; Hu, Liqin; Wu, Yican

    2015-03-01

    An infrared based positioning and tracking (IPT) system was introduced and its accuracy and efficiency for patient setup and monitoring were tested for daily radiotherapy treatment. The IPT system consists of a pair of floor mounted infrared stereoscopic cameras, passive infrared markers and tools used for acquiring localization information as well as a custom controlled software which can perform the positioning and tracking functions. The evaluation of IPT system characteristics was conducted based on the AAPM 147 task report. Experiments on spatial drift and reproducibility as well as static and dynamic localization accuracy were carried out to test the efficiency of the IPT system. Measurements of known translational (up to 55.0 mm) set-up errors in three dimensions have been performed on a calibration phantom. The accuracy of positioning was evaluated on an anthropomorphic phantom with five markers attached to the surface; the precision of the tracking ability was investigated through a sinusoidal motion platform. For the monitoring of the respiration, three volunteers contributed to the breathing testing in real time. The spatial drift of the IPT system was 0.65 mm within 60 min to be stable. The reproducibility of position variations were between 0.01 and 0.04 mm. The standard deviation of static marker localization was 0.26 mm. The repositioning accuracy was 0.19 mm, 0.29 mm, and 0.53 mm in the left/right (L/R), superior/inferior (S/I) and anterior/posterior (A/P) directions, respectively. The measured dynamic accuracy was 0.57 mm and discrepancies measured for the respiratory motion tracking was better than 1 mm. The overall positioning accuracy of the IPT system was within 2 mm. In conclusion, the IPT system is an accurate and effective tool for assisting patient positioning in the treatment room. The characteristics of the IPT system can successfully meet the needs for real time external marker tracking and patient positioning as well as respiration

  10. Diagnostic Accuracy of Perioperative Measurement of Basal Anterior Pituitary and Target Gland Hormones in Predicting Adrenal Insufficiency After Pituitary Surgery.

    PubMed

    Cerina, Vatroslav; Kruljac, Ivan; Radosevic, Jelena Marinkovic; Kirigin, Lora Stanka; Stipic, Darko; Pecina, Hrvoje Ivan; Vrkljan, Milan

    2016-03-01

    The insulin tolerance test (ITT) is the gold standard for diagnosing adrenal insufficiency (AI) after pituitary surgery. The ITT is unpleasant for patients, requires close medical supervision and is contraindicated in several comorbidities. The aim of this study was to analyze whether tumor size, remission rate, preoperative, and early postoperative baseline hormone concentrations could serve as predictors of AI in order to increase the diagnostic accuracy of morning serum cortisol. This prospective study enrolled 70 consecutive patients with newly diagnosed pituitary adenomas. Thirty-seven patients had nonfunctioning pituitary adenomas (NPA), 28 had prolactinomas and 5 had somatotropinomas. Thyroxin (T4), thyrotropin (TSH), prolactin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, and insulin-like growth factor 1 (IGF-I) were measured preoperatively and on the sixth postoperative day. Serum morning cortisol was measured on the third postoperative day (CORT3) as well as the sixth postoperative day (CORT6). Tumor mass was measured preoperatively and remission was assessed 3 months after surgery. An ITT was performed 3 to 6 months postoperatively. Remission was achieved in 48% of patients and AI occurred in 51%. Remission rates and tumor type were not associated with AI. CORT3 had the best predictive value for AI (area under the curve (AUC) 0.868, sensitivity 82.4%, specificity 83.3%). Tumor size, preoperative T4, postoperative T4, and TSH were also associated with AI in a multivariate regression model. A combination of all preoperative and postoperative variables (excluding serum cortisol) had a sensitivity of 75.0% and specificity of 77.8%. The predictive power of CORT3 substantially improved by adding those variables into the model (AUC 0.921, sensitivity 94.1%, specificity 78.3%, PPV 81.9%, NPV of 92.7%). In a subgroup analysis that included only female patients with NPA, LH had exactly the same predictive value as CORT3. The addition

  11. Diagnostic Accuracy of Perioperative Measurement of Basal Anterior Pituitary and Target Gland Hormones in Predicting Adrenal Insufficiency After Pituitary Surgery

    PubMed Central

    Cerina, Vatroslav; Kruljac, Ivan; Radosevic, Jelena Marinkovic; Kirigin, Lora Stanka; Stipic, Darko; Pecina, Hrvoje Ivan; Vrkljan, Milan

    2016-01-01

    Abstract The insulin tolerance test (ITT) is the gold standard for diagnosing adrenal insufficiency (AI) after pituitary surgery. The ITT is unpleasant for patients, requires close medical supervision and is contraindicated in several comorbidities. The aim of this study was to analyze whether tumor size, remission rate, preoperative, and early postoperative baseline hormone concentrations could serve as predictors of AI in order to increase the diagnostic accuracy of morning serum cortisol. This prospective study enrolled 70 consecutive patients with newly diagnosed pituitary adenomas. Thirty-seven patients had nonfunctioning pituitary adenomas (NPA), 28 had prolactinomas and 5 had somatotropinomas. Thyroxin (T4), thyrotropin (TSH), prolactin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, and insulin-like growth factor 1 (IGF-I) were measured preoperatively and on the sixth postoperative day. Serum morning cortisol was measured on the third postoperative day (CORT3) as well as the sixth postoperative day (CORT6). Tumor mass was measured preoperatively and remission was assessed 3 months after surgery. An ITT was performed 3 to 6 months postoperatively. Remission was achieved in 48% of patients and AI occurred in 51%. Remission rates and tumor type were not associated with AI. CORT3 had the best predictive value for AI (area under the curve (AUC) 0.868, sensitivity 82.4%, specificity 83.3%). Tumor size, preoperative T4, postoperative T4, and TSH were also associated with AI in a multivariate regression model. A combination of all preoperative and postoperative variables (excluding serum cortisol) had a sensitivity of 75.0% and specificity of 77.8%. The predictive power of CORT3 substantially improved by adding those variables into the model (AUC 0.921, sensitivity 94.1%, specificity 78.3%, PPV 81.9%, NPV of 92.7%). In a subgroup analysis that included only female patients with NPA, LH had exactly the same predictive value as CORT3. The

  12. Can use of positive religious coping predict greater distress? An examination of Army soldiers on deployment.

    PubMed

    Cornish, Marilyn A; Lannin, Daniel G; Wade, Nathaniel G; Martinez, Melisa

    2017-04-01

    Although positive religious coping is generally viewed as an adaptive, functional coping pattern, some studies have actually found positive religious coping to be associated with more distress in military populations. In the current study, we examined the role of positive religious coping on distress across 2 time points. Participants in this study were 192 Army soldiers (men = 90.4%) who were stationed in Iraq for a 1-year deployment in 2005. Using structural equation modeling, we conducted a cross-lag analysis of positive religious coping and distress. Results indicated that greater use of positive religious coping significantly predicted greater distress 1 month later, whereas distress at T1 did not predict positive religious coping 1 month later. Combat exposure was also a significant predictor of distress 1 month later. Implications of these results include the need to inquire about clients' use of religious coping and whether such coping methods are having the desired effect for them. (PsycINFO Database Record

  13. Trait Reappraisal Predicts Affective Reactivity to Daily Positive and Negative Events

    PubMed Central

    Gunaydin, Gul; Selcuk, Emre; Ong, Anthony D.

    2016-01-01

    Past research on emotion regulation has provided evidence that cognitive reappraisal predicts reactivity to affective stimuli and challenge tests in laboratory settings. However, little is known about how trait reappraisal might contribute to affective reactivity to everyday positive and negative events. Using a large, life-span sample of adults (N = 1755), the present study addressed this important gap in the literature. Respondents completed a measure of trait reappraisal and reported on their daily experiences of positive and negative events and positive and negative affect for eight consecutive days. Results showed that trait reappraisal predicted lower increases in negative affect in response to daily negative events and lower increases in positive affect in response to daily positive events. These findings advance our understanding of the role of reappraisal in emotion regulation by showing how individual differences in the use of this strategy relate to emotional reactions to both positive and negative events outside the laboratory. PMID:27445954

  14. Physical Activity Level Improves the Predictive Accuracy of Cardiovascular Disease Risk Score: The ATTICA Study (2002–2012)

    PubMed Central

    Georgousopoulou, Ekavi N.; Panagiotakos, Demosthenes B.; Bougatsas, Dimitrios; Chatzigeorgiou, Michael; Kavouras, Stavros A.; Chrysohoou, Christina; Skoumas, Ioannis; Tousoulis, Dimitrios; Stefanadis, Christodoulos; Pitsavos, Christos

    2016-01-01

    Background: Although physical activity (PA) has long been associated with cardiovascular disease (CVD), assessment of PA status has never been used as a part of CVD risk prediction tools. The aim of the present work was to examine whether the inclusion of PA status in a CVD risk model improves its predictive accuracy. Methods: Data from the 10-year follow-up (2002–2012) of the n = 2020 participants (aged 18–89 years) of the ATTICA prospective study were used to test the research hypothesis. The HellenicSCORE (that incorporates age, sex, smoking, total cholesterol, and systolic blood pressure levels) was calculated to estimate the baseline 10-year CVD risk; assessment of PA status was based on the International Physical Activity Questionnaire. The estimated CVD risk was tested against the observed 10-year incidence (i.e., development of acute coronary syndromes, stroke, or other CVD according to the World Health Organization [WHO]-International Classification of Diseases [ICD]-10 criteria). Changes in the predictive ability of the nested CVD risk model that contained the HellenicSCORE plus PA assessment were evaluated using Harrell's C and net reclassification index. Results: Both HellenicSCORE and PA status were predictors of future CVD events (P < 0.05). However, the estimating classification bias of the model that included only the HellenicSCORE was significantly reduced when PA assessment was included (Harrel's C = 0.012, P = 0.032); this reduction remained significant even when adjusted for diabetes mellitus and dietary habits (P < 0.05). Conclusions: CVD risk scores seem to be more accurate by incorporating individuals’ PA status; thus, may be more effective tools in primary prevention by efficiently allocating CVD candidates. PMID:27076890

  15. Influence of Ethnicity on the Accuracy of Non-Invasive Scores Predicting Non-Alcoholic Fatty Liver Disease

    PubMed Central

    Xia, Ming-Feng; Yki-Järvinen, Hannele; Bian, Hua; Lin, Huan-Dong; Yan, Hong-Mei; Chang, Xin-Xia; Zhou, You; Gao, Xin

    2016-01-01

    Objectives Presence of non-alcoholic fatty liver disease (NAFLD) can predict risks for diabetes, cardiovascular disease and advanced liver disease in the general population. We aimed to establish a non-invasive score for prediction of NAFLD in Han Chinese, the largest ethnic group in the world, and detect whether ethnicity influences the accuracy of such a score. Methods Liver fat content (LFAT) was measured by quantitative ultrasound in 3548 subjects in the Shanghai Changfeng Community and a Chinese score was created using multivariate logistic regression analyses. This new score was internally validated in Chinese and externally in Finns. Its diagnostic performance was compared to the NAFLD liver fat score, fatty liver index (FLI) and hepatic steatosis index (HSI) developed in Finns, Italians and Koreans. We also analyzed how obesity related to LFAT measured by 1H-MRS in 79 Finns and 118 Chinese with type 2 diabetes (T2D). Results The metabolic syndrome and T2D, fasting serum insulin, body mass index (BMI) and AST/ALT ratio were independent predictors of NAFLD in Chinese. The AUROC in the Chinese validation cohort was 0.76 (0.73–0.78) and in Finns 0.73 (0.68–0.78) (p<0.0001). 43%, 27%, 32% and 42% of Chinese had NAFLD when determined by the Chinese score, NAFLD liver fat score (p<0.001 vs. Chinese score), FLI (p<0.001) and HSI (NS). For any given BMI and waist circumference, the Chinese had a markedly higher LFAT than the Finns. Conclusion The predictors of NAFLD in Han Chinese are as in Europids but the Chinese have more LFAT for any given degree of obesity than Europids. Ethnicity needs to be considered when NAFLD is predicted using risk scores. PMID:27579785

  16. Accuracy of finite element analyses of CT scans in predictions of vertebral failure patterns under axial compression and anterior flexion.

    PubMed

    Jackman, Timothy M; DelMonaco, Alex M; Morgan, Elise F

    2016-01-25

    Finite element (FE) models built from quantitative computed tomography (QCT) scans can provide patient-specific estimates of bone strength and fracture risk in the spine. While prior studies demonstrate accurate QCT-based FE predictions of vertebral stiffness and strength, the accuracy of the predicted failure patterns, i.e., the locations where failure occurs within the vertebra and the way in which the vertebra deforms as failure progresses, is less clear. This study used digital volume correlation (DVC) analyses of time-lapse micro-computed tomography (μCT) images acquired during mechanical testing (compression and anterior flexion) of thoracic spine segments (T7-T9, n=28) to measure displacements occurring throughout the T8 vertebral body at the ultimate point. These displacements were compared to those simulated by QCT-based FE analyses of T8. We hypothesized that the FE predictions would be more accurate when the boundary conditions are based on measurements of pressure distributions within intervertebral discs of similar level of disc degeneration vs. boundary conditions representing rigid platens. The FE simulations captured some of the general, qualitative features of the failure patterns; however, displacement errors ranged 12-279%. Contrary to our hypothesis, no differences in displacement errors were found when using boundary conditions representing measurements of disc pressure vs. rigid platens. The smallest displacement errors were obtained using boundary conditions that were measured directly by DVC at the T8 endplates. These findings indicate that further work is needed to develop methods of identifying physiological loading conditions for the vertebral body, for the purpose of achieving robust, patient-specific FE analyses of failure mechanisms.

  17. Accuracy of finite element analyses of CT scans in predictions of vertebral failure patterns under axial compression and anterior flexion

    PubMed Central

    Jackman, Timothy M.; DelMonaco, Alex M.; Morgan, Elise F.

    2016-01-01

    Finite element (FE) models built from quantitative computed tomography (QCT) scans can provide patient-specific estimates of bone strength and fracture risk in the spine. While prior studies demonstrate accurate QCT-based FE predictions of vertebral stiffness and strength, the accuracy of the predicted failure patterns, i.e., the locations where failure occurs within the vertebra and the way in which the vertebra deforms as failure progresses, is less clear. This study used digital volume correlation (DVC) analyses of time-lapse micro-computed tomography (µCT) images acquired during mechanical testing (compression and anterior flexion) of thoracic spine segments (T7–T9, n = 28) to measure displacements occurring throughout the T8 vertebral body at the ultimate point. These displacements were compared to those simulated by QCT-based FE analyses of T8. We hypothesized that the FE predictions would be more accurate when the boundary conditions are based on measurements of pressure distributions within intervertebral discs of similar level of disc degeneration vs. boundary conditions representing rigid platens. The FE simulations captured some of the general, qualitative features of the failure patterns; however, displacement errors ranged 12–279%. Contrary to our hypothesis, no differences in displacement errors were found when using boundary conditions representing measurements of disc pressure vs. rigid platens. The smallest displacement errors were obtained using boundary conditions that were measured directly by DVC at the T8 endplates. These findings indicate that further work is needed to develop methods of identifying physiological loading conditions for the vertebral body, for the purpose of achieving robust, patient-specific FE analyses of failure mechanisms. PMID:26792288

  18. Mean Expected Error in Prediction of Total Body Water: A True Accuracy Comparison between Bioimpedance Spectroscopy and Single Frequency Regression Equations

    PubMed Central

    Abtahi, Shirin; Abtahi, Farhad; Ellegård, Lars; Johannsson, Gudmundur; Bosaeus, Ingvar

    2015-01-01

    For several decades electrical bioimpedance (EBI) has been used to assess body fluid distribution and body composition. Despite the development of several different approaches for assessing total body water (TBW), it remains uncertain whether bioimpedance spectroscopic (BIS) approaches are more accurate than single frequency regression equations. The main objective of this study was to answer this question by calculating the expected accuracy of a single measurement for different EBI methods. The results of this study showed that all methods produced similarly high correlation and concordance coefficients, indicating good accuracy as a method. Even the limits of agreement produced from the Bland-Altman analysis indicated that the performance of single frequency, Sun's prediction equations, at population level was close to the performance of both BIS methods; however, when comparing the Mean Absolute Percentage Error value between the single frequency prediction equations and the BIS methods, a significant difference was obtained, indicating slightly better accuracy for the BIS methods. Despite the higher accuracy of BIS methods over 50 kHz prediction equations at both population and individual level, the magnitude of the improvement was small. Such slight improvement in accuracy of BIS methods is suggested insufficient to warrant their clinical use where the most accurate predictions of TBW are required, for example, when assessing over-fluidic status on dialysis. To reach expected errors below 4-5%, novel and individualized approaches must be developed to improve the accuracy of bioimpedance-based methods for the advent of innovative personalized health monitoring applications. PMID:26137489

  19. Happiness as a motivator: positive affect predicts primary control striving for career and educational goals.

    PubMed

    Haase, Claudia M; Poulin, Michael J; Heckhausen, Jutta

    2012-08-01

    What motivates individuals to invest time and effort and overcome obstacles (i.e., strive for primary control) when pursuing important goals? We propose that positive affect predicts primary control striving for career and educational goals, and we explore the mediating role of control beliefs. In Study 1, positive affect predicted primary control striving for career goals in a two-wave longitudinal study of a U.S. sample. In Study 2, positive affect predicted primary control striving for career and educational goals and objective career outcomes in a six-wave longitudinal study of a German sample. Control beliefs partially mediated the longitudinal associations with primary control striving. Thus, when individuals experience positive affect, they become more motivated to invest time and effort, and overcome obstacles when pursuing their goals, in part because they believe they have more control over attaining their goals.

  20. Predictive accuracy of amyloid imaging for progression from mild cognitive impairment to Alzheimer disease with different lengths of follow-up: a meta-analysis. [Corrected].

    PubMed

    Ma, Yan; Zhang, Shuo; Li, Jing; Zheng, Dong-Ming; Guo, Yang; Feng, Juan; Ren, Wei-Dong

    2014-12-01

    In the past decade, amyloid deposition has been shown to begin many years before the clinical symptoms of dementia in mild cognitive impairment (MCI) due to Alzheimer disease (AD). Longitudinal studies with different follow-up durations have suggested that C-Pittsburgh compound B positron emission tomography (C-PIB-PET) may play a role in stratifying patients with MCI into risk levels for developing AD. However, the predictive accuracy of amyloid imaging for the progression from MCI to AD with different follow-up durations has not yet been systematically evaluated. A formal systematic evaluation of the sensitivity, specificity, and other properties of C-PIB-PET was performed.This study aimed to systematically review and meta-analyze published data on the diagnostic performance of C-PIB-PET for predicting conversion to AD in patients with MCI and to determine whether long-term follow-up has a positive effect on predictive accuracy. Relevant studies were systematically identified through electronic searches, which were performed in MEDLINE (OvidSP), EMBASE (OvidSP), BIOSIS Previews (ISI Web of Knowledge), Science Citation Index (ISI Web of Knowledge), PsycINFO (Ovid SP), and LILACS (Bireme). The methodological quality of each study was assessed by QUADAS-2. Sensitivities and specificities of C-PIB-PET in individual studies were calculated, and the studies underwent meta-analysis with a random-effects model. A summary receiver-operating characteristic curve (SROC) was constructed with the Moses-Shapiro-Littenberg method. Pooled estimates of sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR-), diagnostic odds ratio (DOR), and the SROC curve of each subgroup were determined. Heterogeneity was tested, and potential sources for heterogeneity were explored by assessing whether certain covariates significantly influenced the relative DOR.Eleven eligible studies consisting of a total of 352 patients with MCI at baseline were included

  1. Predictive Accuracy of Amyloid Imaging for Progression From Mild Cognitive Impairment to Alzheimer Disease With Different Lengths of Follow-up

    PubMed Central

    Ma, Yan; Zhang, Shuo; Li, Jing; Zheng, Dong-Ming; Guo, Yang; Feng, Juan; Ren, Wei-Dong

    2014-01-01

    Abstract In the past decade, amyloid deposition has been shown to begin many years before the clinical symptoms of dementia in mild cognitive impairment (MCI) due to Alzheimer disease (AD). Longitudinal studies with different follow-up durations have suggested that 11C-Pittsburgh compound B positron emission tomography (11C-PIB-PET) may play a role in stratifying patients with MCI into risk levels for developing AD. However, the predictive accuracy of amyloid imaging for the progression from MCI to AD with different follow-up durations has not yet been systematically evaluated. A formal systematic evaluation of the sensitivity, specificity, and other properties of 11C-PIB-PET was performed. This study aimed to systematically review and meta-analyze published data on the diagnostic performance of 11C-PIB-PET for predicting conversion to AD in patients with MCI and to determine whether long-term follow-up has a positive effect on predictive accuracy. Relevant studies were systematically identified through electronic searches, which were performed in MEDLINE (OvidSP), EMBASE (OvidSP), BIOSIS Previews (ISI Web of Knowledge), Science Citation Index (ISI Web of Knowledge), PsycINFO (Ovid SP), and LILACS (Bireme). The methodological quality of each study was assessed by QUADAS-2. Sensitivities and specificities of 11C-PIB-PET in individual studies were calculated, and the studies underwent meta-analysis with a random-effects model. A summary receiver-operating characteristic curve (SROC) was constructed with the Moses-Shapiro-Littenberg method. Pooled estimates of sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR−), diagnostic odds ratio (DOR), and the SROC curve of each subgroup were determined. Heterogeneity was tested, and potential sources for heterogeneity were explored by assessing whether certain covariates significantly influenced the relative DOR. Eleven eligible studies consisting of a total of 352 patients with MCI at

  2. A high-accuracy two-position alignment inertial navigation system for lunar rovers aided by a star sensor with a calibration and positioning function

    NASA Astrophysics Data System (ADS)

    Lu, Jiazhen; Lei, Chaohua; Yang, Yanqiang; Liu, Ming

    2016-12-01

    An integrated inertial/celestial navigation system (INS/CNS) has wide applicability in lunar rovers as it provides accurate and autonomous navigational information. Initialization is particularly vital for a INS. This paper proposes a two-position initialization method based on a standard Kalman filter. The difference between the computed star vector and the measured star vector is measured. With the aid of a star sensor and the two positions, the attitudinal and positional errors can be greatly reduced, and the biases of three gyros and accelerometers can also be estimated. The semi-physical simulation results show that the positional and attitudinal errors converge within 0.07″ and 0.1 m, respectively, when the given initial positional error is 1 km and the attitudinal error is 10°. These good results show that the proposed method can accomplish alignment, positioning and calibration functions simultaneously. Thus the proposed two-position initialization method has the potential for application in lunar rover navigation.

  3. Accuracy of genomic prediction using an evenly spaced, low-density single nucleotide polymorphism panel in broiler chickens.

    PubMed

    Wang, C; Habier, D; Peiris, B L; Wolc, A; Kranis, A; Watson, K A; Avendano, S; Garrick, D J; Fernando, R L; Lamont, S J; Dekkers, J C M

    2013-07-01

    One approach for cost-effective implementation of genomic selection is to genotype training individuals with a high-density (HD) panel and selection candidates with an evenly spaced, low-density (ELD) panel. The purpose of this study was to evaluate the extent to which the ELD approach reduces the accuracy of genomic estimated breeding values (GEBV) in a broiler line, in which 1,091 breeders from 3 generations were used for training and 160 progeny of the third generation for validation. All birds were genotyped with an Illumina Infinium platform HD panel that included 20,541 segregating markers. Two subsets of HD markers, with 377 (ELD-1) or 766 (ELD-2) markers, were selected as ELD panels. The ELD-1 panel was genotyped using KBiosciences KASPar SNP genotyping chemistry, whereas the ELD-2 panel was simulated by adding markers from the HD panel to the ELD-1 panel. The training data set was used for 2 traits: BW at 35 d on both sexes and hen house production (HHP) between wk 28 and 54. Methods Bayes-A, -B, -C and genomic best linear unbiased prediction were used to estimate HD-marker effects. Two scenarios were used: (1) the 160 progeny were ELD-genotyped, and (2) the 160 progeny and their dams (117 birds) were ELD-genotyped. The missing HD genotypes in ELD-genotyped birds were imputed by a Gibbs sampler, capitalizing on linkage within families. In scenario (1), the correlation of GEBV for BW (HHP) of the 160 progeny based on observed HD versus imputed genotypes was greater than 0.94 (0.98) with the ELD-1 panel and greater than 0.97 (0.99) with the ELD-2 panel. In scenario (2), the correlation of GEBV for BW (HHP) was greater than 0.92 (0.96) with the ELD-1 panel and greater than 0.95 (0.98) with the ELD-2 panel. Hence, in a pedigreed population, genomic selection can be implemented by genotyping selection candidates with about 400 ELD markers with less than 6% loss in accuracy. This leads to substantial savings in genotyping costs, with little sacrifice in accuracy.

  4. Accuracy of surface registration compared to conventional volumetric registration in patient positioning for head-and-neck radiotherapy: A simulation study using patient data

    SciTech Connect

    Kim, Youngjun; Li, Ruijiang; Na, Yong Hum; Xing, Lei; Lee, Rena

    2014-12-15

    Purpose: 3D optical surface imaging has been applied to patient positioning in radiation therapy (RT). The optical patient positioning system is advantageous over conventional method using cone-beam computed tomography (CBCT) in that it is radiation free, frameless, and is capable of real-time monitoring. While the conventional radiographic method uses volumetric registration, the optical system uses surface matching for patient alignment. The relative accuracy of these two methods has not yet been sufficiently investigated. This study aims to investigate the theoretical accuracy of the surface registration based on a simulation study using patient data. Methods: This study compares the relative accuracy of surface and volumetric registration in head-and-neck RT. The authors examined 26 patient data sets, each consisting of planning CT data acquired before treatment and patient setup CBCT data acquired at the time of treatment. As input data of surface registration, patient’s skin surfaces were created by contouring patient skin from planning CT and treatment CBCT. Surface registration was performed using the iterative closest points algorithm by point–plane closest, which minimizes the normal distance between source points and target surfaces. Six degrees of freedom (three translations and three rotations) were used in both surface and volumetric registrations and the results were compared. The accuracy of each method was estimated by digital phantom tests. Results: Based on the results of 26 patients, the authors found that the average and maximum root-mean-square translation deviation between the surface and volumetric registrations were 2.7 and 5.2 mm, respectively. The residual error of the surface registration was calculated to have an average of 0.9 mm and a maximum of 1.7 mm. Conclusions: Surface registration may lead to results different from those of the conventional volumetric registration. Only limited accuracy can be achieved for patient

  5. Evaluating the velocity accuracy of an integrated GPS/INS system: Flight test results. [Global positioning system/inertial navigation systems (GPS/INS)

    SciTech Connect

    Owen, T.E.; Wardlaw, R.

    1991-01-01

    Verifying the velocity accuracy of a GPS receiver or an integrated GPS/INS system in a dynamic environment is a difficult proposition when many of the commonly used reference systems have velocity uncertainities of the same order of magnitude or greater than the GPS system. The results of flight tests aboard an aircraft in which multiple reference systems simultaneously collected data to evaluate the accuracy of an integrated GPS/INS system are reported. Emphasis is placed on obtaining high accuracy estimates of the velocity error of the integrated system in order to verify that velocity accuracy is maintained during both linear and circular trajectories. Three different reference systems operating in parallel during flight tests are used to independently determine the position and velocity of an aircraft in flight. They are a transponder/interrogator ranging system, a laser tracker, and GPS carrier phase processing. Results obtained from these reference systems are compared against each other and against an integrated real time differential based GPS/INS system to arrive at a set of conclusions about the accuracy of the integrated system.

  6. Study on desirable ionospheric corrections accuracy for network-RTK positioning and its impact on time-to-fix and probability of successful single-epoch ambiguity resolution

    NASA Astrophysics Data System (ADS)

    Paziewski, Jacek

    2016-02-01

    The mitigation of ionospheric delay is still of crucial interest in GNSS positioning, especially in precise solutions such as instantaneous RTK positioning. Thus, several effective algorithms and functional models were developed, and also numerous investigations of ionospheric correction properties in RTK positioning have been performed so far. One of the most highly effective approaches in precise relative positioning is the application of the ionosphere-weighted model with network-derived corrections. This contribution investigates the impact of the accuracy of the network ionospheric corrections on time-to-fix in RTK-OTF positioning. Also, an attempt has been made to estimate the desirable accuracy of the network ionospheric corrections, allowing for reliable instantaneous ambiguity resolution. The experiment is based on a multi-baseline GPS RTK positioning supported with network-derived ionospheric corrections for medium length baselines. The results show that in such scenario, the double-differenced ionospheric correction residuals should not exceed ∼1/3 of the L1 wavelength for successful single-epoch ambiguity resolution.

  7. A Novel Wavelet-Based Approach for Predicting Nucleosome Positions Using DNA Structural Information.

    PubMed

    Gan, Yanglan; Zou, Guobing; Guan, Jihong; Xu, Guangwei

    2014-01-01

    Nucleosomes are basic elements of chromatin structure. The positioning of nucleosomes along a genome is very important to dictate eukaryotic DNA compaction and access. Current computational methods have focused on the analysis of nucleosome occupancy and the positioning of well-positioned nucleosomes. However, fuzzy nucleosomes require more complex configurations and are more difficult to predict their positions. We analyzed the positioning of well-positioned and fuzzy nucleosomes from a novel structural perspective, and proposed WaveNuc, a computational approach for inferring their positions based on continuous wavelet transformation. The comparative analysis demonstrates that these two kinds of nucleosomes exhibit different propeller twist structural characteristics. Well-positioned nucleosomes tend to locate at sharp peaks of the propeller twist profile, whereas fuzzy nucleosomes correspond to broader peaks. The sharpness of these peaks shows that the propeller twist profile may contain nucleosome positioning information. Exploiting this knowledge, we applied WaveNuc to detect the two different kinds of peaks of the propeller twist profile along the genome. We compared the performance of our method with existing methods on real data sets. The results show that the proposed method can accurately resolve complex configurations of fuzzy nucleosomes, which leads to better performance of nucleosome positioning prediction on the whole genome.

  8. Predicting the infrared transition intensities in the Ar-HF complex: the key role of the dipole moment surface accuracy.

    PubMed

    Jankowski, Piotr; Ziółkowski, Marcin

    2008-01-21

    The method proposed earlier for the generation of the full-dimensional energy surface for van der Waals complexes [P. Jankowski, J. Chem. Phys. 121, 1655 (2004)] is used to obtain a fulldimensional dipole moment surface for the atom-diatom complex in calculations based on the coupled-cluster with single, double, and noniterative triple excitation approach and the aug-cc-pVQZ basis sets. This surface has been employed to calculate transition intensities of the infrared spectra of Ar-HF. Special attention has been paid to study the problem of relative intensities of the different bands which have not been properly predicted within the long-range models of the dipole moment [A. E. Thornley and J. M. Hutson, J. Chem. Phys. 101, 5578 (1994)]. The intensities calculated with the present dipole moment surface agree very well with the experimental data, which indicate that the short-range interactions significantly affect the dipole moment surface and the calculated intensities. To investigate the role of the accuracy of the dipole moment surface on infrared transition intensities in atom-diatom complexes, four models of increasing complexity are studied. Their performance is shown to strongly depend on the region of the interaction energy surface probed by the initial and final states of the individual transitions.

  9. Incremental validity of positive and negative valence in predicting personality disorder.

    PubMed

    Simms, Leonard J; Yufik, Tom; Gros, Daniel F

    2010-04-01

    The Big Seven model of personality includes five dimensions similar to the Big Five model as well as two evaluative dimensions—Positive Valence (PV) and Negative Valence (NV)—which reflect extremely positive and negative person descriptors, respectively. Recent theory and research have suggested that PV and NV predict significant variance in personality disorder (PD) above that predicted by the Big Five, but firm conclusions have not been possible because previous studies have been limited to only single measures of PV, NV, and the Big Five traits. In the present study, we replicated and extended previous findings using three markers of all key constructs—including PV, NV, and the Big Five—in a diverse sample of 338 undergraduates. Results of hierarchical multiple regression analyses revealed that PV incrementally predicted Narcissistic and Histrionic PDs above the Big Five and that NV nonspecifically incremented the prediction of most PDs. Implications for dimensional models of personality pathology are discussed.

  10. Queuing Time Prediction Using WiFi Positioning Data in an Indoor Scenario

    PubMed Central

    Shu, Hua; Song, Ci; Pei, Tao; Xu, Lianming; Ou, Yang; Zhang, Libin; Li, Tao

    2016-01-01

    Queuing is common in urban public places. Automatically monitoring and predicting queuing time can not only help individuals to reduce their wait time and alleviate anxiety but also help managers to allocate resources more efficiently and enhance their ability to address emergencies. This paper proposes a novel method to estimate and predict queuing time in indoor environments based on WiFi positioning data. First, we use a series of parameters to identify the trajectories that can be used as representatives of queuing time. Next, we divide the day into equal time slices and estimate individuals’ average queuing time during specific time slices. Finally, we build a nonstandard autoregressive (NAR) model trained using the previous day’s WiFi estimation results and actual queuing time to predict the queuing time in the upcoming time slice. A case study comparing two other time series analysis models shows that the NAR model has better precision. Random topological errors caused by the drift phenomenon of WiFi positioning technology (locations determined by a WiFi positioning system may drift accidently) and systematic topological errors caused by the positioning system are the main factors that affect the estimation precision. Therefore, we optimize the deployment strategy during the positioning system deployment phase and propose a drift ratio parameter pertaining to the trajectory screening phase to alleviate the impact of topological errors and improve estimates. The WiFi positioning data from an eight-day case study conducted at the T3-C entrance of Beijing Capital International Airport show that the mean absolute estimation error is 147 s, which is approximately 26.92% of the actual queuing time. For predictions using the NAR model, the proportion is approximately 27.49%. The theoretical predictions and the empirical case study indicate that the NAR model is an effective method to estimate and predict queuing time in indoor public areas. PMID:27879663

  11. Queuing Time Prediction Using WiFi Positioning Data in an Indoor Scenario.

    PubMed

    Shu, Hua; Song, Ci; Pei, Tao; Xu, Lianming; Ou, Yang; Zhang, Libin; Li, Tao

    2016-11-22

    Queuing is common in urban public places. Automatically monitoring and predicting queuing time can not only help individuals to reduce their wait time and alleviate anxiety but also help managers to allocate resources more efficiently and enhance their ability to address emergencies. This paper proposes a novel method to estimate and predict queuing time in indoor environments based on WiFi positioning data. First, we use a series of parameters to identify the trajectories that can be used as representatives of queuing time. Next, we divide the day into equal time slices and estimate individuals' average queuing time during specific time slices. Finally, we build a nonstandard autoregressive (NAR) model trained using the previous day's WiFi estimation results and actual queuing time to predict the queuing time in the upcoming time slice. A case study comparing two other time series analysis models shows that the NAR model has better precision. Random topological errors caused by the drift phenomenon of WiFi positioning technology (locations determined by a WiFi positioning system may drift accidently) and systematic topological errors caused by the positioning system are the main factors that affect the estimation precision. Therefore, we optimize the deployment strategy during the positioning system deployment phase and propose a drift ratio parameter pertaining to the trajectory screening phase to alleviate the impact of topological errors and improve estimates. The WiFi positioning data from an eight-day case study conducted at the T3-C entrance of Beijing Capital International Airport show that the mean absolute estimation error is 147 s, which is approximately 26.92% of the actual queuing time. For predictions using the NAR model, the proportion is approximately 27.49%. The theoretical predictions and the empirical case study indicate that the NAR model is an effective method to estimate and predict queuing time in indoor public areas.

  12. Accuracy of Computed Tomography for Predicting Pathologic Nodal Extracapsular Extension in Patients With Head-and-Neck Cancer Undergoing Initial Surgical Resection

    SciTech Connect

    Prabhu, Roshan S.; Magliocca, Kelly R.; Hanasoge, Sheela; Aiken, Ashley H.; Hudgins, Patricia A.; Hall, William A.; Chen, Susie A.; Eaton, Bree R.; Higgins, Kristin A.; Saba, Nabil F.; Beitler, Jonathan J.

    2014-01-01

    Purpose: Nodal extracapsular extension (ECE) in patients with head-and-neck cancer increases the loco-regional failure risk and is an indication for adjuvant chemoradiation therapy (CRT). To reduce the risk of requiring trimodality therapy, patients with head-and-neck cancer who are surgical candidates are often treated with definitive CRT when preoperative computed tomographic imaging suggests radiographic ECE. The purpose of this study was to assess the accuracy of preoperative CT imaging for predicting pathologic nodal ECE (pECE). Methods and Materials: The study population consisted of 432 consecutive patients with oral cavity or locally advanced/nonfunctional laryngeal cancer who underwent preoperative CT imaging before initial surgical resection and neck dissection. Specimens with pECE had the extent of ECE graded on a scale from 1 to 4. Results: Radiographic ECE was documented in 46 patients (10.6%), and pECE was observed in 87 (20.1%). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 43.7%, 97.7%, 82.6%, and 87.3%, respectively. The sensitivity of radiographic ECE increased from 18.8% for grade 1 to 2 ECE, to 52.9% for grade 3, and 72.2% for grade 4. Radiographic ECE criteria of adjacent structure invasion was a better predictor than irregular borders/fat stranding for pECE. Conclusions: Radiographic ECE has poor sensitivity, but excellent specificity for pECE in patients who undergo initial surgical resection. PPV and NPV are reasonable for clinical decision making. The performance of preoperative CT imaging increased as pECE grade increased. Patients with resectable head-and-neck cancer with radiographic ECE based on adjacent structure invasion are at high risk for high-grade pECE requiring adjuvant CRT when treated with initial surgery; definitive CRT as an alternative should be considered where appropriate.

  13. Accuracy of three-dimensional measurements obtained from cone beam computed tomography surface-rendered images for cephalometric analysis: influence of patient scanning position.

    PubMed

    Hassan, Bassam; van der Stelt, Paul; Sanderink, Gerard

    2009-04-01

    The aims of this study were to assess the accuracy of linear measurements on three-dimensional (3D) surface-rendered images generated from cone beam computed tomography (CBCT) in comparison with two-dimensional (2D) slices and 2D lateral and postero-anterior (PA) cephalometric projections, and to investigate the influence of patient head position in the scanner on measurement accuracy. Eight dry human skulls were scanned twice using NewTom 3G CBCT in an ideal and a rotated position and the resulting datasets were used to create 3D surface-rendered images, 2D tomographic slices, and 2D lateral and PA projections. Ten linear distances were defined for cephalometric measurements. The physical and radiographic measurements were repeated twice by three independent observers and were compared using repeated measures analysis of variance (P=0.05). The radiographic measurements were also compared between the ideal and the rotated scan positions. The radiographic measurements of the 3D images were closer to the physical measurements than the 2D slices and 2D projection images. No statistically significant difference was found between the ideal and the rotated scan measurements for the 3D images and the 2D tomographic slices. A statistically significant difference (P<0.001) was observed between the ideal and rotated scan positions for the 2D projection images. The findings indicate that measurements based on 3D CBCT surface images are accurate and that small variations in the patient's head position do not influence measurement accuracy.

  14. Mediofrontal event-related potentials in response to positive, negative and unsigned prediction errors.

    PubMed

    Sambrook, Thomas D; Goslin, Jeremy

    2014-08-01

    Reinforcement learning models make use of reward prediction errors (RPEs), the difference between an expected and obtained reward. There is evidence that the brain computes RPEs, but an outstanding question is whether positive RPEs ("better than expected") and negative RPEs ("worse than expected") are represented in a single integrated system. An electrophysiological component, feedback related negativity, has been claimed to encode an RPE but its relative sensitivity to the utility of positive and negative RPEs remains unclear. This study explored the question by varying the utility of positive and negative RPEs in a design that controlled for other closely related properties of feedback and could distinguish utility from salience. It revealed a mediofrontal sensitivity to utility, for positive RPEs at 275-310ms and for negative RPEs at 310-390ms. These effects were preceded and succeeded by a response consistent with an unsigned prediction error, or "salience" coding.

  15. Improvement of walking speed prediction by accelerometry and altimetry, validated by satellite positioning.

    PubMed

    Perrin, O; Terrier, P; Ladetto, Q; Merminod, B; Schutz, Y

    2000-03-01

    Activity monitors based on accelerometry are used to predict the speed and energy cost of walking at 0% slope, but not at other inclinations. Parallel measurements of body accelerations and altitude variation were studied to determine whether walking speed prediction could be improved. Fourteen subjects walked twice along a 1.3 km circuit with substantial slope variations (-17% to +17%). The parameters recorded were body acceleration using a uni-axial accelerometer, altitude variation using differential barometry, and walking speed using satellite positioning (DGPS). Linear regressions were calculated between acceleration and walking speed, and between acceleration/altitude and walking speed. These predictive models, calculated using the data from the first circuit run, were used to predict speed during the second circuit. Finally the predicted velocity was compared with the measured one. The result was that acceleration alone failed to predict speed (mean r = 0.4). Adding altitude variation improved the prediction (mean r = 0.7). With regard to the altitude/acceleration-speed relationship, substantial inter-individual variation was found. It is concluded that accelerometry, combined with altitude measurement, can assess position variations of humans provided inter-individual variation is taken into account. It is also confirmed that DGPS can be used for outdoor walking speed measurements, opening up new perspectives in the field of biomechanics.

  16. Predicting adolescent substance use: the effects of depressed mood and positive expectancies.

    PubMed

    Clark, Heddy Kovach; Ringwalt, Chris L; Shamblen, Stephen R

    2011-05-01

    This study examined whether sixth-graders' depressed mood and positive substance use expectancies predicted increases over the next two years in students' lifetime and 30-day cigarette, alcohol, and marijuana use, and whether sixth graders' positive substance use expectancies moderated the relationship between baseline depressed mood and changes over the next two years in the use of these substances. Study data came from a randomized controlled trial of Project ALERT, a school-based substance use prevention program, in which students from 34 schools completed self-report surveys as sixth (n=5782), seventh (n=5065), and eighth graders (n=4940). Primary analyses were performed using Hierarchical Nonlinear Modeling. Over time, there were significant effects of baseline positive expectancies on each of the six measures of substance use. Baseline depressed mood predicted increases over time only for lifetime use of cigarettes and alcohol, and for 30-day alcohol use. Positive expectancies significantly moderated the effects of adolescent depressed mood only on lifetime marijuana use. Although depressed mood predicted substance use for half of our variables, our results suggest that positive expectancies are a more consistent predictor of adolescent substance use, and that they may moderate the effects of depressed mood on marijuana, but not cigarette or alcohol, use. Substance use prevention programs may benefit from addressing adolescents' perceptions about the positive consequences of drug use.

  17. Critical Features Predicting Sustained Implementation of School-Wide Positive Behavioral Interventions and Supports

    ERIC Educational Resources Information Center

    Mathews, Susanna; McIntosh, Kent; Frank, Jennifer L.; May, Seth L.

    2014-01-01

    The current study explored the extent to which a common measure of perceived implementation of critical features of Positive Behavioral Interventions and Supports (PBIS) predicted fidelity of implementation 3 years later. Respondents included school personnel from 261 schools across the United States implementing PBIS. School teams completed the…

  18. Critical Features Predicting Sustained Implementation of School-Wide Positive Behavior Support

    ERIC Educational Resources Information Center

    Mathews, Susanna; McIntosh, Kent; Frank, Jennifer; May, Seth

    2014-01-01

    The current study explored the extent to which a common measure of perceived implementation of critical features of School-wide Positive Behavior Support (SWPBS) predicted fidelity of implementation 3 years later. Respondents included school personnel from 261 schools across the United States implementing SWPBS. School teams completed the…

  19. Extreme Appraisals of Internal States and Bipolar Symptoms: The Hypomanic Attitudes and Positive Predictions Inventory

    ERIC Educational Resources Information Center

    Dodd, Alyson L.; Mansell, Warren; Morrison, Anthony P.; Tai, Sara

    2011-01-01

    The Hypomanic Attitudes and Positive Predictions Inventory (HAPPI; W. Mansell, 2006) was developed to assess multiple, extreme, self-relevant appraisals of internal states. The present study aimed to validate the HAPPI in a clinical sample. Participants (N = 50) with a diagnosis of bipolar disorder (confirmed by a structured clinical interview)…

  20. Development of X-Y servo pneumatic-piezoelectric hybrid actuators for position control with high response, large stroke and nanometer accuracy.

    PubMed

    Chiang, Mao-Hsiung

    2010-01-01

    This study aims to develop a X-Y dual-axial intelligent servo pneumatic-piezoelectric hybrid actuator for position control with high response, large stroke (250 mm, 200 mm) and nanometer accuracy (20 nm). In each axis, the rodless pneumatic actuator serves to position in coarse stroke and the piezoelectric actuator compensates in fine stroke. Thus, the overall control systems of the single axis become a dual-input single-output (DISO) system. Although the rodless pneumatic actuator has relatively larger friction force, it has the advantage of mechanism for multi-axial development. Thus, the X-Y dual-axial positioning system is developed based on the servo pneumatic-piezoelectric hybrid actuator. In addition, the decoupling self-organizing fuzzy sliding mode control is developed as the intelligent control strategies. Finally, the proposed novel intelligent X-Y dual-axial servo pneumatic-piezoelectric hybrid actuators are implemented and verified experimentally.

  1. Study of accuracy in the position determination with SALSA, a γ-scanning system for the characterization of segmented HPGe detectors

    NASA Astrophysics Data System (ADS)

    Hernandez-Prieto, A.; Quintana, B.; Martìn, S.; Domingo-Pardo, C.

    2016-07-01

    Accurate characterization of the electric response of segmented high-purity germanium (HPGe) detectors as a function of the interaction position is one of the current goals of the Nuclear Physics community seeking to perform γ-ray tracking or even imaging with these detectors. For this purpose, scanning devices must be developed to achieve the signal-position association with the highest precision. With a view to studying the accuracy achieved with SALSA, the SAlamanca Lyso-based Scanning Array, here we report a detailed study on the uncertainty sources and their effect in the position determination inside the HPGe detector to be scanned. The optimization performed on the design of SALSA, aimed at minimizing the effect of the uncertainty sources, afforded an intrinsic uncertainty of ∼2 mm for large coaxial detectors and ∼1 mm for planar ones.

  2. Improved accuracy and speed in scanning probe microscopy by image reconstruction from non-gridded position sensor data

    NASA Astrophysics Data System (ADS)

    Ziegler, Dominik; Meyer, Travis R.; Farnham, Rodrigo; Brune, Christoph; Bertozzi, Andrea L.; Ashby, Paul D.

    2013-08-01

    Scanning probe microscopy (SPM) has facilitated many scientific discoveries utilizing its strengths of spatial resolution, non-destructive characterization and realistic in situ environments. However, accurate spatial data are required for quantitative applications but this is challenging for SPM especially when imaging at higher frame rates. We present a new operation mode for scanning probe microscopy that uses advanced image processing techniques to render accurate images based on position sensor data. This technique, which we call sensor inpainting, frees the scanner to no longer be at a specific location at a given time. This drastically reduces the engineering effort of position control and enables the use of scan waveforms that are better suited for the high inertia nanopositioners of SPM. While in raster scanning, typically only trace or retrace images are used for display, in Archimedean spiral scans 100% of the data can be displayed and at least a two-fold increase in temporal or spatial resolution is achieved. In the new mode, the grid size of the final generated image is an independent variable. Inpainting to a few times more pixels than the samples creates images that more accurately represent the ground truth.

  3. Electromagnetic Real-Time Tumor Position Monitoring and Dynamic Multileaf Collimator Tracking Using a Siemens 160 MLC: Geometric and Dosimetric Accuracy of an Integrated System

    SciTech Connect

    Krauss, Andreas; Nill, Simeon; Tacke, Martin; Oelfke, Uwe

    2011-02-01

    Purpose: Dynamic multileaf collimator tracking represents a promising method for high-precision radiotherapy to moving tumors. In the present study, we report on the integration of electromagnetic real-time tumor position monitoring into a multileaf collimator-based tracking system. Methods and Materials: The integrated system was characterized in terms of its geometric and radiologic accuracy. The former was assessed from portal images acquired during radiation delivery to a phantom in tracking mode. The tracking errors were calculated from the positions of the tracking field and of the phantom as extracted from the portal images. Radiologic accuracy was evaluated from film dosimetry performed for conformal and intensity-modulated radiotherapy applied to different phantoms moving on sinusoidal trajectories. A static radiation delivery to the nonmoving target served as a reference for the delivery to the moving phantom with and without tracking applied. Results: Submillimeter tracking accuracy was observed for two-dimensional target motion despite the relatively large system latency of 500 ms. Film dosimetry yielded almost complete recovery of a circular dose distribution with tracking in two dimensions applied: 2%/2 mm gamma-failure rates could be reduced from 59.7% to 3.3%. For single-beam intensity-modulated radiotherapy delivery, accuracy was limited by the finite leaf width. A 2%/2 mm gamma-failure rate of 15.6% remained with tracking applied. Conclusion: The integrated system we have presented marks a major step toward the clinical implementation of high-precision dynamic multileaf collimator tracking. However, several challenges such as irregular motion traces or a thorough quality assurance still need to be addressed.

  4. Does information available at delivery improve the accuracy of predicting vaginal birth after cesarean? Validation of the published models in an independent patient cohort.

    PubMed

    Costantine, Maged M; Fox, Karin A; Pacheco, Luis Diego; Mateus, Julio; Hankins, Gary D V; Grobman, William A; Saade, George R

    2011-04-01

    We sought to validate a proposed vaginal birth after cesarean (VBAC) prediction model that includes variables available "at or close to delivery" and compare its accuracy to one that only uses variables available at "entry to care." We performed a retrospective cohort study of term pregnant women with a vertex singleton gestation attempting a trial of labor (TOL) after a single prior low transverse cesarean delivery. VBAC rates, predicted using the "close to delivery" model, were partitioned into deciles. The observed VBAC rate in each partition was compared with the predicted one. The accuracy of the two models was compared using the receiver operating characteristics curve. The predicted VBAC probability was higher in patients who had VBAC compared with those who failed a TOL (median [interquartile range]: 74.9% [59.6 to 86.1] versus 48.6% [35.4 to 66.7]; P < 0.001). The correlation between the observed and predicted VBAC rates was high (R = 0.98; P < 0.001). In the subset of patients who had the complete set of variables available for the two models (N = 490), the "close to delivery" model was more accurate. We validated the proposed VBAC prediction model in an independent cohort. Incorporating information available at delivery improves its accuracy.

  5. Accuracy of Ultrasound-Based Image Guidance for Daily Positioning of the Upper Abdomen: An Online Comparison With Cone Beam CT

    SciTech Connect

    Boda-Heggemann, Judit Mennemeyer, Philipp; Wertz, Hansjoerg; Riesenacker, Nadja; Kuepper, Beate; Lohr, Frank; Wenz, Frederik

    2009-07-01

    Purpose: Image-guided intensity-modulated radiotherapy can improve protection of organs at risk when large abdominal target volumes are irradiated. We estimated the daily positioning accuracy of ultrasound-based image guidance for abdominal target volumes by a direct comparison of daily imaging obtained with cone beam computed tomography (CBCT). Methods and Materials: Daily positioning (n = 83 positionings) of 15 patients was completed by using ultrasound guidance after an initial CBCT was obtained. Residual error after ultrasound was estimated by comparison with a second CBCT. Ultrasound image quality was visually rated using a scale of 1 to 4. Results: Of 15 patients, 7 patients had good sonographic imaging quality, 5 patients had satisfactory sonographic quality, and 3 patients were excluded because of unsatisfactory sonographic quality. When image quality was good, residual errors after ultrasound were -0.1 {+-} 3.11 mm in the x direction (left-right; group systematic error M = -0.09 mm; standard deviation [SD] of systematic error, {sigma} = 1.37 mm; SD of the random error, {sigma} = 2.99 mm), 0.93 {+-} 4.31 mm in the y direction (superior-inferior, M = 1.12 mm; {sigma} = 2.96 mm; {sigma} = 3.39 mm), and 0.71 {+-} 3.15 mm in the z direction (anteroposterior; M = 1.01 mm; {sigma} = 2.46 mm; {sigma} = 2.24 mm). For patients with satisfactory image quality, residual error after ultrasound was -0.6 {+-} 5.26 mm in the x (M = 0.07 mm; {sigma} = 5.67 mm; {sigma} = 4.86 mm), 1.76 {+-} 4.92 mm in the y (M = 3.54 mm; {sigma} = 4.1 mm; {sigma} = 5.29 mm), and 1.19 {+-} 4.75 mm in the z (M = 0.82 mm; {sigma} = 2.86 mm; {sigma} = 3.05 mm) directions. Conclusions: In patients from whom good sonographic image quality could be obtained, ultrasound improved daily positioning accuracy. In the case of satisfactory image quality, ultrasound guidance improved accuracy compared to that of skin marks only minimally. If sonographic image quality was unsatisfactory, daily CBCT

  6. Predicting the size of the progeny mapping population required to positionally clone a gene.

    PubMed

    Dinka, Stephen J; Campbell, Matthew A; Demers, Tyler; Raizada, Manish N

    2007-08-01

    A key frustration during positional gene cloning (map-based cloning) is that the size of the progeny mapping population is difficult to predict, because the meiotic recombination frequency varies along chromosomes. We describe a detailed methodology to improve this prediction using rice (Oryza sativa L.) as a model system. We derived and/or validated, then fine-tuned, equations that estimate the mapping population size by comparing these theoretical estimates to 41 successful positional cloning attempts. We then used each validated equation to test whether neighborhood meiotic recombination frequencies extracted from a reference RFLP map can help researchers predict the mapping population size. We developed a meiotic recombination frequency map (MRFM) for approximately 1400 marker intervals in rice and anchored each published allele onto an interval on this map. We show that neighborhood recombination frequencies (R-map, >280-kb segments) extracted from the MRFM, in conjunction with the validated formulas, better predicted the mapping population size than the genome-wide average recombination frequency (R-avg), with improved results whether the recombination frequency was calculated as genes/cM or kb/cM. Our results offer a detailed road map for better predicting mapping population size in diverse eukaryotes, but useful predictions will require robust recombination frequency maps based on sampling more progeny.

  7. A positive Babinski reflex predicts delayed neuropsychiatric sequelae in Chinese patients with carbon monoxide poisoning.

    PubMed

    Zou, Jian-Fang; Guo, Qiming; Shao, Hua; Li, Bin; Du, Yuxiu; Liu, Maofeng; Liu, Fengling; Dai, Lixin; Chung, Min-Hsien; Lin, Hung-Jung; Guo, How-Ran; Yang, Tzu-Meng; Huang, Chien-Cheng; Hsu, Chien-Chin

    2014-01-01

    As the human population increased in China, the carbon monoxide is a serious environmental toxin in public health. However, predicting the delayed neuropsychiatric sequelae (DNS) of carbon monoxide poisoning (COP) has not been well studied. We investigated the independent predictors of DNS in patients with COP. This study was conducted at four hospitals in China. Data were retrospectively collected from 258 patients with COP between November 1990 and October 2011. DNS was the primary endpoint. A positive Babinski reflex was the independent predictor for DNS: sensitivity = 53.8% (95% confidence interval [CI]: 26.1-79.6), specificity = 88.6% (95% CI: 83.7-92.1), positive predictive value (PPV) = 20.0% (95% CI: 9.1-37.5), and negative predictive value (NPV) = 97.3% (95% CI: 94.0-98.9). The area under the receiver operating characteristic curve = 0.712 (95% CI: 0.544-0.880). A positive Babinski reflex was very memorable, immediately available, and applicable in clinical practice. Even when the sensitivity and PPV of a positive Babinski reflex were unsatisfactory, it had a good specificity and NPV for excluding the risk of DNS. In patients without a positive Babinski reflex, the risk for DNS was only 2.7%. This finding may help physicians make decisions about dispositions for patients with COP.

  8. Accuracy of an infrared marker-based patient positioning system (ExacTrac®) for stereotactic body radiotherapy in localizing the planned isocenter using fiducial markers

    SciTech Connect

    Montes-Rodríguez, María de los Ángeles Mitsoura, Eleni; Hernández-Bojórquez, Mariana; Martínez-Gómez, Alma Angélica; Contreras-Pérez, Agustín; Negrete-Hernández, Ingrid Mireya; Hernández-Oviedo, Jorge Omar; Santiago-Concha, Bernardino Gabriel

    2014-11-07

    Stereotactic Body Radiation Therapy (SBRT) requires a controlled immobilization and position monitoring of patient and target. The purpose of this work is to analyze the performance of the imaging system ExacTrac® (ETX) using infrared and fiducial markers. Materials and methods: In order to assure the accuracy of isocenter localization, a Quality Assurance procedure was applied using an infrared marker-based positioning system. Scans were acquired of an inhouse-agar gel and solid water phantom with infrared spheres. In the inner part of the phantom, three reference markers were delineated as reference and one pellet was place internally; which was assigned as the isocenter. The iPlan® RT Dose treatment planning system. Images were exported to the ETX console. Images were acquired with the ETX to check the correctness of the isocenter placement. Adjustments were made in 6D the reference markers were used to fuse the images. Couch shifts were registered. The procedure was repeated for verification purposes. Results: The data recorded of the verifications in translational and rotational movements showed averaged 3D spatial uncertainties of 0.31 ± 0.42 mm respectively 0.82° ± 0.46° in the phantom and the first correction of these uncertainties were of 1.51 ± 1.14 mm respectively and 1.37° ± 0.61°. Conclusions: This study shows a high accuracy and repeatability in positioning the selected isocenter. The ETX-system for verifying the treatment isocenter position has the ability to monitor the tracing position of interest, making it possible to be used for SBRT positioning within uncertainty ≤1mm.

  9. Accuracy of an infrared marker-based patient positioning system (ExacTrac®) for stereotactic body radiotherapy in localizing the planned isocenter using fiducial markers

    NASA Astrophysics Data System (ADS)

    Montes-Rodríguez, María de los Ángeles; Hernández-Bojórquez, Mariana; Martínez-Gómez, Alma Angélica; Contreras-Pérez, Agustín; Negrete-Hernández, Ingrid Mireya; Hernández-Oviedo, Jorge Omar; Mitsoura, Eleni; Santiago-Concha, Bernardino Gabriel

    2014-11-01

    Stereotactic Body Radiation Therapy (SBRT) requires a controlled immobilization and position monitoring of patient and target. The purpose of this work is to analyze the performance of the imaging system ExacTrac® (ETX) using infrared and fiducial markers. Materials and methods: In order to assure the accuracy of isocenter localization, a Quality Assurance procedure was applied using an infrared marker-based positioning system. Scans were acquired of an inhouse-agar gel and solid water phantom with infrared spheres. In the inner part of the phantom, three reference markers were delineated as reference and one pellet was place internally; which was assigned as the isocenter. The iPlan® RT Dose treatment planning system. Images were exported to the ETX console. Images were acquired with the ETX to check the correctness of the isocenter placement. Adjustments were made in 6D the reference markers were used to fuse the images. Couch shifts were registered. The procedure was repeated for verification purposes. Results: The data recorded of the verifications in translational and rotational movements showed averaged 3D spatial uncertainties of 0.31 ± 0.42 mm respectively 0.82° ± 0.46° in the phantom and the first correction of these uncertainties were of 1.51 ± 1.14 mm respectively and 1.37° ± 0.61°. Conclusions: This study shows a high accuracy and repeatability in positioning the selected isocenter. The ETX-system for verifying the treatment isocenter position has the ability to monitor the tracing position of interest, making it possible to be used for SBRT positioning within uncertainty ≤1mm.

  10. Accuracy of Prediction Equations to Assess Percentage of Body Fat in Children and Adolescents with Down Syndrome Compared to Air Displacement Plethysmography

    ERIC Educational Resources Information Center

    Gonzalez-Aguero, A.; Vicente-Rodriguez, G.; Ara, I.; Moreno, L. A.; Casajus, J. A.

    2011-01-01

    To determine the accuracy of the published percentage body fat (%BF) prediction equations (Durnin et al., Johnston et al., Brook and Slaughter et al.) from skinfold thickness compared to air displacement plethysmography (ADP) in children and adolescents with Down syndrome (DS). Twenty-eight children and adolescents with DS (10-20 years old; 12…

  11. Cervical Radiculopathy and Carpal Tunnel Syndrome: A Prospective Determination of the Reliability, Diagnostic Accuracy, and Predictive Validity fo Commonly Used Clinical

    DTIC Science & Technology

    2007-11-02

    Patients with cervical radiculopathy and carpal tunnel syndrome result in significant medical and occupational costs annually. There is a need to...of diagnostic accuracy. and predictive validity of items of the clinical examination used for the diagnosis of cervical radiculopathy and carpal tunnel syndrome.

  12. Predictive Utility and Classification Accuracy of Oral Reading Fluency and the Measures of Academic Progress for the Wisconsin Knowledge and Concepts Exam

    ERIC Educational Resources Information Center

    Ball, Carrie R.; O'Connor, Edward

    2016-01-01

    This study examined the predictive validity and classification accuracy of two commonly used universal screening measures relative to a statewide achievement test. Results indicated that second-grade performance on oral reading fluency and the Measures of Academic Progress (MAP), together with special education status, explained 68% of the…

  13. Toddler Inhibitory Control, Bold Response to Novelty, and Positive Affect Predict Externalizing Symptoms in Kindergarten

    PubMed Central

    Buss, Kristin A.; Kiel, Elizabeth J.; Morales, Santiago; Robinson, Emily

    2013-01-01

    Poor inhibitory control and bold-approach have been found to predict the development of externalizing behavior problems in young children. Less research has examined how positive affect may influence the development of externalizing behavior in the context of low inhibitory control and high approach. We used a multimethod approach to examine how observed toddler inhibitory control, bold-approach, and positive affect predicted externalizing outcomes (observed, adult- and self-reported) in additive and interactive ways at the beginning of kindergarten. 24-month-olds (N = 110) participated in a laboratory visit and 84 were followed up in kindergarten for externalizing behaviors. Overall, children who were low in inhibitory control, high in bold-approach, and low in positive affect at 24-months of age were at greater risk for externalizing behaviors during kindergarten. PMID:25018589

  14. Predicting suicidal behaviours using clinical instruments: systematic review and meta-analysis of positive predictive values for risk scales.

    PubMed

    Carter, Gregory; Milner, Allison; McGill, Katie; Pirkis, Jane; Kapur, Navneet; Spittal, Matthew J

    2017-03-16

    BackgroundPrediction of suicidal behaviour is an aspirational goal for clinicians and policy makers; with patients classified as 'high risk' to be preferentially allocated treatment. Clinical usefulness requires an adequate positive predictive value (PPV).AimsTo identify studies of predictive instruments and to calculate PPV estimates for suicidal behaviours.MethodA systematic review identified studies of predictive instruments. A series of meta-analyses produced pooled estimates of PPV for suicidal behaviours.ResultsFor all scales combined, the pooled PPVs were: suicide 5.5% (95% CI 3.9-7.9%), self-harm 26.3% (95% CI 21.8-31.3%) and self-harm plus suicide 35.9% (95% CI 25.8-47.4%). Subanalyses on self-harm found pooled PPVs of 16.1% (95% CI 11.3-22.3%) for high-quality studies, 32.5% (95% CI 26.1-39.6%) for hospital-treated self-harm and 26.8% (95% CI 19.5-35.6%) for psychiatric in-patients.ConclusionsNo 'high-risk' classification was clinically useful. Prevalence imposes a ceiling on PPV. Treatment should reduce exposure to modifiable risk factors and offer effective interventions for selected subpopulations and unselected clinical populations.

  15. Validation of the North American Chest Pain Rule in Prediction of Very Low-Risk Chest Pain; a Diagnostic Accuracy Study

    PubMed Central

    Valadkhani, Somayeh; Jalili, Mohammad; Hesari, Elham; Mirfazaelian, Hadi

    2017-01-01

    Introduction: Acute coronary syndrome accounts for more than 15% of the chest pains. Recently, Hess et al. developed North American Chest Pain Rule (NACPR) to identify very low-risk patients who can be safely discharged from emergency department (ED). The present study aimed to validate this rule in EDs of two academic hospitals. Methods: A prospective diagnostic accuracy study was conducted on consecutive patients 24 years of age and older presenting to the ED with the chief complaint of acute chest pain, during March 2013 to June 2013. Chest pain characteristics, cardiac history, electrocardiogram findings, and cardiac biomarker measurement of patients were collected and screening performance characteristics of NACPR with 95% confidence interval were calculated using SPSS 21. Results: From 400 eligible patients with completed follow up, 69 (17.25 %) developed myocardial infarction, 121 (30.25%) underwent coronary revascularization, and 4 (2%) died because of cardiac or unidentifiable causes. By using NACPR, 34 (8.50%) of all the patients could be considered very low- risk and discharged after a brief ED assessment. Among these patients, none developed above-mentioned adverse outcomes within 30 days. Sensitivity, specificity, positive prediction value, and negative prediction value of the rule were 100% (95% CI: 87.35 - 100.00), 45.35 (95% CI: 40.19 - 50.61), 14.52 (95% CI: 10.40 – 19.85), and 100 (95% CI: 97.18 - 100.00), respectively. Conclusions: The present multicenter study showed that NACPR is a good screening tool for early discharge of patients with very low-risk chest pain from ED. PMID:28286818

  16. Potential of EnMAP spaceborne imaging spectroscopy for the prediction of common surface soil properties and expected accuracy

    NASA Astrophysics Data System (ADS)

    Chabrillat, Sabine; Foerster, Saskia; Steinberg, Andreas; Stevens, Antoine; Segl, Karl

    2016-04-01

    There is a renewed awareness of the finite nature of the world's soil resources, growing concern about soil security, and significant uncertainties about the carrying capacity of the planet. As a consequence, soil scientists are being challenged to provide regular assessments of soil conditions from local through to global scales. However, only a few countries have the necessary survey and monitoring programs to meet these new needs and existing global data sets are out-of-date. A particular issue is the clear demand for a new area-wide regional to global coverage with accurate, up-to-date, and spatially referenced soil information as expressed by the modeling scientific community, farmers and land users, and policy and decision makers. Soil spectroscopy from remote sensing observations based on studies from the laboratory scale to the airborne scale has been shown to be a proven method for the quantitative prediction of key soil surface properties in local areas for exposed soils in appropriate surface conditions such as low vegetation cover and low water content. With the upcoming launch of the next generation of hyperspectral satellite sensors in the next 3 to 5 years (EnMAP, HISUI, PRISMA, SHALOM), a great potential for the global mapping and monitoring of soil properties is appearing. Nevertheless, the capabilities to extend the soil properties current spectral modeling from local to regional scales are still to be demonstrated using robust methods. In particular, three central questions are at the forefront of research nowadays: a) methodological developments toward improved algorithms and operational tools for the extraction of soil properties, b) up scaling from the laboratory into space domain, and c) demonstration of the potential of upcoming satellite systems and expected accuracy of soil maps. In this study, airborne imaging spectroscopy data from several test sites are used to simulate EnMAP satellite images at 30 m scale. Then, different soil

  17. Situational Motivation and Perceived Intensity: Their Interaction in Predicting Changes in Positive Affect from Physical Activity

    PubMed Central

    Guérin, Eva; Fortier, Michelle S.

    2012-01-01

    There is evidence that affective experiences surrounding physical activity can contribute to the proper self-regulation of an active lifestyle. Motivation toward physical activity, as portrayed by self-determination theory, has been linked to positive affect, as has the intensity of physical activity, especially of a preferred nature. The purpose of this experimental study was to examine the interaction between situational motivation and intensity [i.e., ratings of perceived exertion (RPE)] in predicting changes in positive affect following an acute bout of preferred physical activity, namely, running. Fourty-one female runners engaged in a 30-minute self-paced treadmill run in a laboratory context. Situational motivation for running, pre- and post-running positive affect, and RPE were assessed via validated self-report questionnaires. Hierarchical regression analyses revealed a significant interaction effect between RPE and introjection (P < .05) but not between RPE and identified regulation or intrinsic motivation. At low levels of introjection, the influence of RPE on the change in positive affect was considerable, with higher RPE ratings being associated with greater increases in positive affect. The implications of the findings in light of SDT principles as well as the potential contingencies between the regulations and RPE in predicting positive affect among women are discussed. PMID:22778914

  18. Positioning.

    ERIC Educational Resources Information Center

    Conone, Ruth M.

    The key to positioning is the creation of a clear benefit image in the consumer's mind. One positioning strategy is creating in the prospect's mind a position that takes into consideration the company's or agency's strengths and weaknesses as well as those of its competitors. Another strategy is to gain entry into a position ladder owned by…

  19. Navigated non-image-based registration of the position of the pelvis during THR. An accuracy and reproducibility study.

    PubMed

    Jenny, Jean-Yves; Boeri, Cyril; Ciobanu, Eugen

    2008-05-01

    The precise recording of the position of the pelvis is a prerequisite for total hip replacement (THR). The anterior pelvic plane is an accepted reference for determining the 3D pelvic orientation. We hypothesized that cutaneous palpation of this plane was accurate and reproducible. Ten consecutive navigated implantations of THR prostheses were studied. In each case, four palpations of both anterior iliac spines and the pubic symphysis were performed with a navigated stylus. The first palpation was made on actual bone contours through a skin puncture and was considered as the reference. The other three palpations were made over the intact skin as a normal intra-operative procedure. There was no significant difference between the pelvic orientations measured by the three cutaneous palpations, or between the orientations measured by transcutaneous palpation and the mean result with cutaneous palpation. Cutaneous palpation can be considered as a reliable technique for the definition of pelvic orientation during THR with the non-image-based system employed.

  20. Disturbance in hitting accuracy by professional and collegiate baseball players due to intentional change of target position.

    PubMed

    Higuchi, Takatoshi; Nagami, Tomoyuki; Morohoshi, Jun; Nakata, Hiroki; Kanosue, Kazuyuki

    2013-04-01

    The present study investigated bat control of skilled baseball batters during tee batting, faced with an intentional change in target position. Twelve, skilled, male baseball players (M age = 24 yr., SD = 4) participated in the study. Participants were instructed to hit a baseball off a tee 0.8 m from the ground (Hitting condition), and also to deliberately swing just above the ball (Air Swing condition). The task for the participants was to perform, in alternate order, 15 swings at a real baseball on a stationary tee and 15 swings at an imaginary ball that was said to be on top of the real baseball. The participants were instructed to hit the ball toward center field just as they would hit in a game. While most participants could hit the real ball in the sweet area of the bat, only one participant did so in the Air Swing condition. Average distances from the center of the sweet area to ball center at the moment of ball-bat contact in the Air Swing condition (85 mm) were significantly greater than the distance in the Hitting condition (38 mm). The larger error in hitting an imaginary ball in the sweet area could be due to perceptual changes following the batter's altered focus, expectation of a lack of contact, and/or lack of feedback from the swing. It was suggested that baseball batters should be aware of the possible error in hitting accurately when they intentionally shifted the target.

  1. Ionospheric corrections estimation in a local GNSS permanent stations network: improvement of Code Point Positioning at sub-metric accuracy level

    NASA Astrophysics Data System (ADS)

    Brunini, C.; Crespi, M.; Mazzoni, A.

    2008-12-01

    It is well know that GNSS permanent networks for real-time positioning were mainly designed to generate and transmit products for RTK (or Network-RTK) positioning. In this context, RTK products are restricted to users equipped with geodetic-class receivers. This work is a first step toward using a local network of permanent GNSS stations to generate and transmit real time products that could remarkably improve positioning accuracy for C/A receiver users. A simple experiment was carried out based on 3 consecutive days of data from 3 permanent stations that belong to the RESNAP-GPS network (w3.uniroma1.it/resnap-gps), located at the Lazio Region (Central Italy) and managed by DITS-Area di Geodesia e Geomatica, Sapienza University of Rome. In the first step the RINEX files were corrected for the differential code biases according to IGS recommendations and then processed with Bernese 5.0 CODSPP module (single point positioning using code measurements), using IGS precise ephemeris and clocks. One position per epoch (every 30 seconds) was estimated for P1 and for the ionosphere free combination (P3). The accuracy obtained with the P3 combination for the vertical component, which ranged from -1 to +1 m, was taken as the reference for the following discussion. For P1 observations, the vertical coordinate errors showed a typical signature due to the ionospheric activity: higher errors for day-time (up to 5 m) and smaller ones for night-time (around 1.5 m). In order to improve the accuracy of the P1 solution, ionospheric corrections were estimated using the La Plata Ionospheric Model, based on the dual-frequency observations from the RESNAP-GPS network. Those corrections were applied to the RINEX files of a probing station located within the reference network. With this procedure, the vertical coordinate errors were reduced to the range from -0.8 to 0.8 m. This methodological approach shows the possibility to remarkably improve the real time positioning based on Code

  2. Ionospheric corrections estimation in a local GNSS permanent stations network: improvement of Code Point Positioning at sub-metric accuracy level

    NASA Astrophysics Data System (ADS)

    Brunini, C.; Crespi, M.; Mazzoni, A.

    2009-04-01

    It is well know that GNSS permanent networks for real-time positioning were mainly designed to generate and transmit products for RTK (or Network-RTK) positioning. In this context, RTK products are restricted to users equipped with geodetic-class receivers. This work is a first step toward using a local network of permanent GNSS stations to generate and transmit real time products that could remarkably improve positioning accuracy for C/A receiver users. A simple experiment was carried out based on 3 consecutive days of data from 3 permanent stations that belong to the RESNAP-GPS network (w3.uniroma1.it/resnap-gps), located at the Lazio Region (Central Italy) and managed by DITS-Area di Geodesia e Geomatica, Sapienza University of Rome. In the first step the RINEX files were corrected for the differential code biases according to IGS recommendations and then processed with Bernese 5.0 CODSPP module (single point positioning using code measurements), using IGS precise ephemeris and clocks. One position per epoch (every 30 seconds) was estimated for P1 and for the ionosphere free combination (P3). The accuracy obtained with the P3• combination for the vertical component, which ranged from -1 to +1 m, was taken as the reference for the following discussion. For P1 observations, the vertical coordinate errors showed a typical signature due to the ionospheric activity: higher errors for day-time (up to 5 m) and smaller ones for night-time (around 1.5 m). In order to improve the accuracy of the P1 solution, ionospheric corrections were estimated using the La Plata Ionospheric Model, based on the dual-frequency observations from the RESNAP-GPS network. Those corrections were applied to the RINEX files of a probing station located within the reference network. With this procedure, the vertical coordinate errors were reduced to the range from -0.8 to 0.8 m. This methodological approach shows the possibility to remarkably improve the real time positioning based on Code

  3. Effects of Recovery Behavior and Strain-Rate Dependence of Stress-Strain Curve on Prediction Accuracy of Thermal Stress Analysis During Casting

    NASA Astrophysics Data System (ADS)

    Motoyama, Yuichi; Shiga, Hidetoshi; Sato, Takeshi; Kambe, Hiroshi; Yoshida, Makoto

    2017-03-01

    Recovery behavior (recovery) and strain-rate dependence of the stress-strain curve (strain-rate dependence) are incorporated into constitutive equations of alloys to predict residual stress and thermal stress during casting. Nevertheless, few studies have systematically investigated the effects of these metallurgical phenomena on the prediction accuracy of thermal stress in a casting. This study compares the thermal stress analysis results with in situ thermal stress measurement results of an Al-Si-Cu specimen during casting. The results underscore the importance for the alloy constitutive equation of incorporating strain-rate dependence to predict thermal stress that develops at high temperatures where the alloy shows strong strain-rate dependence of the stress-strain curve. However, the prediction accuracy of the thermal stress developed at low temperatures did not improve by considering the strain-rate dependence. Incorporating recovery into the constitutive equation improved the accuracy of the simulated thermal stress at low temperatures. Results of comparison implied that the constitutive equation should include strain-rate dependence to simulate defects that develop from thermal stress at high temperatures, such as hot tearing and hot cracking. Recovery should be incorporated into the alloy constitutive equation to predict the casting residual stress and deformation caused by the thermal stress developed mainly in the low temperature range.

  4. Does morphology predict trophic position and habitat use of ant species and assemblages?

    PubMed

    Gibb, H; Stoklosa, J; Warton, D I; Brown, A M; Andrew, N R; Cunningham, S A

    2015-02-01

    A functional traits-based theory of organismal communities is critical for understanding the principles underlying community assembly, and predicting responses to environmental change. This is particularly true for terrestrial arthropods, of which only 20% are described. Using epigaeic ant assemblages, we asked: (1) can we use morphological variation among species to predict trophic position or preferred microhabitat; (2) does the strength of morphological associations suggest recent trait divergence; (3) do environmental variables at site scale predict trait sets for whole assemblages? We pitfall-trapped ants from a revegetation chronosequence and measured their morphology, trophic position [using C:N stoichiometry and stable isotope ratios (δ)] and characteristics of microhabitat and macrohabitat. We found strong associations between high trophic position (low C:N and high δ(15)N) in body tissue and morphological traits: predators were larger, had more laterally positioned eyes, more physical protection and tended to be monomorphic. In addition, morphological traits were associated with certain microhabitat features, e.g. smaller heads were associated with the bare ground microhabitat. Trait-microhabitat relationships were more pronounced when phylogenetic adjustments were used, indicating a strong influence of recent trait divergences. At the assemblage level, our fourth corner analysis revealed associations between the prevalence of traits and macrohabitat, although these associations were not the same as those based on microhabitat associations. This study shows direct links between species-level traits and both diet and habitat preference. Trait-based prediction of ecological roles and community structure is thus achievable when integrating stoichiometry, morphology and phylogeny, but scale is an important consideration in such predictions.

  5. Predictability, plausibility, and two late ERP positivities during written sentence comprehension

    PubMed Central

    DeLong, Katherine A.; Quante, Laura; Kutas, Marta

    2014-01-01

    Van Petten & Luka’s (2012) literature survey of late positive ERP components elicited by more or less predictable words during sentence processing led them to propose two topographically and functionally distinct positivities: a parietal one associated with semantically incongruent words related to semantic reanalysis and a frontal one with unknown significance associated with congruent but lexically unpredicted words. With the goal of testing this hypothesis within a single set of experimental materials and participants, we report results from two ERP studies: Experiment 1, a post hoc analysis of a dataset that varied on dimensions of both cloze probability (predictability) and plausibility, and Experiment 2, a follow-up study in which these factors were manipulated in a controlled fashion. In both studies, we observed distinct post-N400 positivities: a more anterior one to plausible, but not anomalous, low cloze probability sentence medial words, and a more posterior one to semantically anomalous sentence continuations. Taken together with an observed canonical cloze-modulated N400, these dual positivities indicate a dissociation between brain processes relating to written words’ sentential predictability versus plausibility, clearly an important distinction for any viable neural or psycholinguistic model of written sentence processing. PMID:24953958

  6. Interplay effects between dose distribution quality and positioning accuracy in total marrow irradiation with volumetric modulated arc therapy

    SciTech Connect

    Mancosu, Pietro; Navarria, Piera; Reggiori, Giacomo; Tomatis, Stefano; Alongi, Filippo; Scorsetti, Marta; Castagna, Luca; Sarina, Barbara; Nicolini, Giorgia; Fogliata, Antonella; Cozzi, Luca

    2013-11-15

    Purpose: To evaluate the dosimetric consequences of inaccurate isocenter positioning during treatment of total marrow (lymph-node) irradiation (TMI-TMLI) using volumetric modulated arc therapy (VMAT).Methods: Four patients treated with TMI and TMLI were randomly selected from the internal database. Plans were optimized with VMAT technique. Planning target volume (PTV) included all the body bones; for TMLI, lymph nodes and spleen were considered into the target, too. Dose prescription to PTV was 12 Gy in six fractions, two times per day for TMI, and 2 Gy in single fraction for TMLI. Ten arcs on five isocenters (two arcs for isocenter) were used to cover the upper part of PTV (i.e., from cranium to middle femurs). For each plan, three series of random shifts with values between −3 and +3 mm and three between −5 and +5 mm were applied to the five isocenters simulating involuntary patient motion during treatment. The shifts were applied separately in the three directions: left–right (L-R), anterior–posterior (A-P), and cranial–caudal (C-C). The worst case scenario with simultaneous random shifts in all directions simultaneously was considered too. Doses were recalculated for the 96 shifted plans (24 for each patient).Results: For all shifts, differences <0.5% were found for mean doses to PTV, body, and organs at risk with volumes >100 cm{sup 3}. Maximum doses increased up to 15% for C-C shifted plans. PTV covered by the 95% isodose decreased of 2%–8% revealing target underdosage with the highest values in C-C direction.Conclusions: The correct isocenter repositioning of TMI-TMLI patients is fundamental, in particular in C-C direction, in order to avoid over- and underdosages especially in the overlap regions. For this reason, a dedicated immobilization system was developed in the authors' center to best immobilize the patient.

  7. Suspicion of Motives Predicts Minorities’ Responses to Positive Feedback in Interracial Interactions

    PubMed Central

    Major, Brenda; Kunstman, Jonathan W.; Malta, Brenna D.; Sawyer, Pamela J.; Townsend, Sarah S. M.; Mendes, Wendy Berry

    2015-01-01

    Strong social and legal norms in the United States discourage the overt expression of bias against ethnic and racial minorities, increasing the attributional ambiguity of Whites’ positive behavior to ethnic minorities. Minorities who suspect that Whites’ positive overtures toward minorities are motivated more by their fear of appearing racist than by egalitarian attitudes may regard positive feedback they receive from Whites as disingenuous. This may lead them to react to such feedback with feelings of uncertainty and threat. Three studies examined how suspicion of motives relates to ethnic minorities’ responses to receiving positive feedback from a White peer or same-ethnicity peer (Experiment 1), to receiving feedback from a White peer that was positive or negative (Experiment 2), and to receiving positive feedback from a White peer who did or did not know their ethnicity (Experiment 3). As predicted, the more suspicious Latinas were of Whites’ motives for behaving positively toward minorities in general, the more they regarded positive feedback from a White peer who knew their ethnicity as disingenuous and the more they reacted with cardiovascular reactivity characteristic of threat/avoidance, increased feelings of stress, heightened uncertainty, and decreased self-esteem. We discuss the implications for intergroup interactions of perceptions of Whites’ motives for nonprejudiced behavior. PMID:26688594

  8. Positive thinking about the future in newspaper reports and presidential addresses predicts economic downturn.

    PubMed

    Sevincer, A Timur; Wagner, Greta; Kalvelage, Johanna; Oettingen, Gabriele

    2014-04-01

    Previous research has shown that positive thinking, in the form of fantasies about an idealized future, predicts low effort and poor performance. In the studies reported here, we used computerized content analysis of historical documents to investigate the relation between positive thinking about the future and economic development. During the financial crisis from 2007 to 2009, the more weekly newspaper articles in the economy page of USA Today contained positive thinking about the future, the more the Dow Jones Industrial Average declined in the subsequent week and 1 month later. In addition, between the New Deal era and the present time, the more presidential inaugural addresses contained positive thinking about the future, the more the gross domestic product and the employment rate declined in the presidents' subsequent tenures. These counterintuitive findings may help reveal the psychological processes that contribute to an economic crisis.

  9. CFD simulation of pollutant dispersion around isolated buildings: on the role of convective and turbulent mass fluxes in the prediction accuracy.

    PubMed

    Gousseau, P; Blocken, B; van Heijst, G J F

    2011-10-30

    Computational Fluid Dynamics (CFD) is increasingly used to predict wind flow and pollutant dispersion around buildings. The two most frequently used approaches are solving the Reynolds-averaged Navier-Stokes (RANS) equations and Large-Eddy Simulation (LES). In the present study, we compare the convective and turbulent mass fluxes predicted by these two approaches for two configurations of isolated buildings with distinctive features. We use this analysis to clarify the role of these two components of mass transport on the prediction accuracy of RANS and LES in terms of mean concentration. It is shown that the proper simulation of the convective fluxes is essential to predict an accurate concentration field. In addition, appropriate parameterization of the turbulent fluxes is needed with RANS models, while only the subgrid-scale effects are modeled with LES. Therefore, when the source is located outside of recirculation regions (case 1), both RANS and LES can provide accurate results. When the influence of the building is higher (case 2), RANS models predict erroneous convective fluxes and are largely outperformed by LES in terms of prediction accuracy of mean concentration. These conclusions suggest that the choice of the appropriate turbulence model depends on the configuration of the dispersion problem under study. It is also shown that for both cases LES predicts a counter-gradient mechanism of the streamwise turbulent mass transport, which is not reproduced by the gradient-diffusion hypothesis that is generally used with RANS models.

  10. Predictive and Prognostic Value of the 21-Gene Recurrence Score in Hormone Receptor–positive, Node-positive Breast Cancer

    PubMed Central

    2014-01-01

    The addition of adjuvant chemotherapy to hormonal therapy is recommended for patients with estrogen receptor–positive (ER+), node-positive (N+) early breast cancer (EBC). Some of these patients, however, are not likely to benefit from treatment and may, therefore, be overtreated while also incurring unnecessary treatment-related adverse events and health care costs. The 21-gene Recurrence Score assay has been clinically validated and recommended for use in patients with ER+, node-negative (N0) EBC to assess the 10-year risk of distant disease recurrence and predict the likelihood of response to adjuvant chemotherapy. A growing body of evidence from several large phase III clinical trials reports similar findings in patients with ER+, N+ EBC. A systematic review of published literature from key clinical trials that have used the 21-gene breast cancer assay in patients with ER+, N+ EBC was performed. The Recurrence Score has been shown to be an independent predictor of disease-free survival, overall survival, and distant recurrence-free interval in patients with ER+, N+ EBC. Outcomes from decision impact and health economics studies further indicate that the Recurrence Score affects physician treatment recommendations equally in patients with N+ or N0 disease. It also indicates that a reduction in Recurrence Score–directed chemotherapy is cost-effective. There is a large body of evidence to support the use of the 21-gene assay Recurrence Score in patients with N+ EBC. Use of this assay could help guide treatment decisions for patients who are most likely to receive benefit from chemotherapy. PMID:24853663

  11. Development of a video image-based QA system for the positional accuracy of dynamic tumor tracking irradiation in the Vero4DRT system

    SciTech Connect

    Ebe, Kazuyu Tokuyama, Katsuichi; Baba, Ryuta; Ogihara, Yoshisada; Ichikawa, Kosuke; Toyama, Joji; Sugimoto, Satoru; Utsunomiya, Satoru; Kagamu, Hiroshi; Aoyama, Hidefumi; Court, Laurence

    2015-08-15

    Purpose: To develop and evaluate a new video image-based QA system, including in-house software, that can display a tracking state visually and quantify the positional accuracy of dynamic tumor tracking irradiation in the Vero4DRT system. Methods: Sixteen trajectories in six patients with pulmonary cancer were obtained with the ExacTrac in the Vero4DRT system. Motion data in the cranio–caudal direction (Y direction) were used as the input for a programmable motion table (Quasar). A target phantom was placed on the motion table, which was placed on the 2D ionization chamber array (MatriXX). Then, the 4D modeling procedure was performed on the target phantom during a reproduction of the patient’s tumor motion. A substitute target with the patient’s tumor motion was irradiated with 6-MV x-rays under the surrogate infrared system. The 2D dose images obtained from the MatriXX (33 frames/s; 40 s) were exported to in-house video-image analyzing software. The absolute differences in the Y direction between the center of the exposed target and the center of the exposed field were calculated. Positional errors were observed. The authors’ QA results were compared to 4D modeling function errors and gimbal motion errors obtained from log analyses in the ExacTrac to verify the accuracy of their QA system. The patients’ tumor motions were evaluated in the wave forms, and the peak-to-peak distances were also measured to verify their reproducibility. Results: Thirteen of sixteen trajectories (81.3%) were successfully reproduced with Quasar. The peak-to-peak distances ranged from 2.7 to 29.0 mm. Three trajectories (18.7%) were not successfully reproduced due to the limited motions of the Quasar. Thus, 13 of 16 trajectories were summarized. The mean number of video images used for analysis was 1156. The positional errors (absolute mean difference + 2 standard deviation) ranged from 0.54 to 1.55 mm. The error values differed by less than 1 mm from 4D modeling function errors

  12. The positive predictive value of guaiac faecal occult blood test in relation to the number of positive squares in two consecutive rounds of colorectal cancer screening.

    PubMed

    Manfredi, Sylvain; Philip, Julie; Campillo, Boris; Piette, Christine; Durand, Gerard; Riou, Françoise; Bretagne, Jean François

    2011-07-01

    The aim of this study was to define the positive predictive values of a positive guaiac faecal occult blood test according to the number of positive squares, in two consecutive rounds of colorectal cancer mass screening in a French region. A total of 4172 colonoscopies were analyzed. Sex, age, number of positive squares, and colonoscopic and histopathologic findings were studied. In the results obtained, 76.6% of positive tests were positive with one or two squares. The number of positive squares was not related to sex, age and rank of participation. The positive predictive value for cancers and adenomas increased significantly with age, sex (male) and number of positive squares from 6.6% (one to two squares) to 27.6% (five to six squares) and from 15.2% to 22.2%, respectively. Cancer was diagnosed 211 times (54.1%) and advanced neoplasia was diagnosed 696 times (65.3%) following positive tests with one to two squares. The TNM stage of cancer increased significantly with the number of positive squares: 85.8% of stages 0-1-2 for one to two positive squares and 66.3% for five to six positive squares (P<0.001). Multivariate analysis showed an increased risk of cancer and advanced neoplasia for male patients and aged persons. The number of positive squares significantly increased the risk of cancer (odds ratio=4.6 for five to six positive squares) and the risk of advanced neoplasia (odds ratio=2.9). Age, sex and number of positive squares were independent predictive factors of positive guaiac faecal occult blood test. The proportion of TNM stages 3-4 was significantly higher in those with five to six positive squares. Performing a complete colonoscopy in every individual having a positive test, especially aged men with a high number of positive squares, should be a priority in any screening programme.

  13. Predicting Early Positive Change in Multisystemic Therapy with Youth Exhibiting Antisocial Behaviors

    PubMed Central

    Tiernan, Kristine; Foster, Sharon L.; Cunningham, Phillippe B.; Brennan, Patricia; Whitmore, Elizabeth

    2016-01-01

    This study examined individual and family characteristics that predicted early positive change in the context of Multisystemic Therapy (MST). Families (n=185; 65% male; average youth age 15 years) receiving MST in community settings completed assessments at the outset of treatment and 6-12 weeks into treatment. Early positive changes in youth antisocial behavior were assessed using the caregiver report on the CBCL Externalizing Behaviors subscale and youth report on the Self-Report Delinquency Scale. Overall, families showed significant positive changes by 6-12 weeks into treatment; these early changes were maintained into mid-treatment 6-12 weeks later. Families who exhibited clinically significant gains early in treatment were more likely to terminate treatment successfully compared to those who did not show these gains. Low youth internalizing behaviors and absence of youth drug use predicted early positive changes in MST. High levels of parental monitoring and low levels of affiliation with deviant peers (mechanisms known to be associated with MST success) were also associated with early positive change. PMID:24866967

  14. Prediction of metastatic relapse in node-positive breast cancer: establishment of a clinicogenomic model after FEC100 adjuvant regimen.

    PubMed

    Campone, Mario; Campion, Loïc; Roché, Henry; Gouraud, Wilfried; Charbonnel, Catherine; Magrangeas, Florence; Minvielle, Stéphane; Genève, Jean; Martin, Anne-Laure; Bataille, Régis; Jézéquel, Pascal

    2008-06-01

    Breast cancer is a very heterogeneous disease, and markers for disease subtypes and therapy response remain poorly defined. For that reason, we employed a retrospective study in node-positive breast cancer to identify molecular signatures of gene expression correlating with metastatic free survival. Patients were primarily included in FEC100 (5-fluorouracil 500 mg/m(2), epirubicin 100 mg/m(2) and cyclophosphamide 500 mg/m(2)) arms of two multicentric prospective adjuvant clinical trials (PACS01 and PEGASE01-FNCLCC cooperative group). Data from nylon microarrays containing 8,032 cDNA unique sequences, representing 5,776 distinct genes, have been used to develop a predictive model for treatment outcome. We obtained the gene expression profiles for 150 of these patients, and used stringent univariate selection techniques based on Cox regression combined with principal component analysis to identify a genomic signature of metastatic relapse after adjuvant FEC100 regimen. Most of the 14 selected genes have a clear role in breast cancer, carcinogenesis or chemotherapy resistance. Six genes have been previously described in other genomic studies (UBE2C, CENPF, C16orf61 [DC13], STMN1, CCT5 and BCL2A1). Furthermore, we showed the interest of combining transcriptomic data with clinical data into a clinicogenomic model for patients subtyping. The described model adds predictive accuracy to that provided by the well-established Nottingham prognostic index or by our genomic signature alone.

  15. An analysis on combined GPS/COMPASS data quality and its effect on single point positioning accuracy under different observing conditions

    NASA Astrophysics Data System (ADS)

    Cai, Changsheng; Gao, Yang; Pan, Lin; Dai, Wujiao

    2014-09-01

    With the rapid development of the COMPASS system, it is currently capable of providing regional navigation services. In order to test its data quality and performance for single point positioning (SPP), experiments have been conducted under different observing conditions including open sky, under trees, nearby a glass wall, nearby a large area of water, under high-voltage lines and under a signal transmitting tower. To assess the COMPASS data quality, the code multipath, cycle slip occurrence rate and data availability were analyzed and compared to GPS data. The datasets obtained from the experiments have also been utilized to perform combined GPS/COMPASS SPP on an epoch-by-epoch basis using unsmoothed single-frequency code observations. The investigation on the regional navigation performance aims at low-accuracy applications and all tests are made in Changsha, China, using the “SOUTH S82-C” GPS/COMPASS receivers. The results show that adding COMPASS observations can significantly improve the positioning accuracy of single-frequency GPS-only SPP in environments with limited satellite visibility. Since the COMPASS system is still in an initial operational stage, all results are obtained based on a fairly limited amount of data.

  16. A method to improve the stability and accuracy of ANN- and SVM-based time series models for long-term groundwater level predictions

    NASA Astrophysics Data System (ADS)

    Yoon, Heesung; Hyun, Yunjung; Ha, Kyoochul; Lee, Kang-Kun; Kim, Gyoo-Bum

    2016-05-01

    The prediction of long-term groundwater level fluctuations is necessary to effectively manage groundwater resources and to assess the effects of changes in rainfall patterns on groundwater resources. In the present study, a weighted error function approach was utilised to improve the performance of artificial neural network (ANN)- and support vector machine (SVM)-based recursive prediction models for the long-term prediction of groundwater levels in response to rainfall. The developed time series models were applied to groundwater level data from 5 groundwater-monitoring stations in South Korea. The results demonstrated that the weighted error function approach can improve the stability and accuracy of recursive prediction models, especially for ANN models. The comparison of the model performance showed that the recursive prediction performance of the SVM was superior to the performance of the ANN in this case study.

  17. Continuous and Discrete Space Particle Filters for Predictions in Acoustic Positioning

    NASA Astrophysics Data System (ADS)

    Bauer, Will; Kim, Surrey; Kouritzin, Michael A.

    2002-12-01

    Predicting the future state of a random dynamic signal based on corrupted, distorted, and partial observations is vital for proper real-time control of a system that includes time delay. Motivated by problems from Acoustic Positioning Research Inc., we consider the continual automated illumination of an object moving within a bounded domain, which requires object location prediction due to inherent mechanical and physical time lags associated with robotic lighting. Quality computational predictions demand high fidelity models for the coupled moving object signal and observation equipment pair. In our current problem, the signal represents the vector position, orientation, and velocity of a stage performer. Acoustic observations are formed by timing ultrasonic waves traveling from four perimeter speakers to a microphone attached to the performer. The goal is to schedule lighting movements that are coordinated with the performer by anticipating his/her future position based upon these observations using filtering theory. Particle system based methods have experienced rapid development and have become an essential technique of contemporary filtering strategies. Hitherto, researchers have largely focused on continuous state particle filters, ranging from traditional weighted particle filters to adaptive refining particle filters, readily able to perform path-space estimation and prediction. Herein, we compare the performance of a state-of-the-art refining particle filter to that of a novel discrete-space particle filter on the acoustic positioning problem. By discrete space particle filter we mean a Markov chain that counts particles in discretized cells of the signal state space in order to form an approximated unnormalized distribution of the signal state. For both filters mentioned above, we will examine issues like the mean time to localize a signal, the fidelity of filter estimates at various signal to noise ratios, computational costs, and the effect of signal

  18. Performance Feedback Processing Is Positively Biased As Predicted by Attribution Theory

    PubMed Central

    Rodriguez Buritica, Julia M.; Heekeren, Hauke R.

    2016-01-01

    A considerable literature on attribution theory has shown that healthy individuals exhibit a positivity bias when inferring the causes of evaluative feedback on their performance. They tend to attribute positive feedback internally (e.g., to their own abilities) but negative feedback externally (e.g., to environmental factors). However, all empirical demonstrations of this bias suffer from at least one of the three following drawbacks: First, participants directly judge explicit causes for their performance. Second, participants have to imagine events instead of experiencing them. Third, participants assess their performance only after receiving feedback and thus differences in baseline assessments cannot be excluded. It is therefore unclear whether the classically reported positivity bias generalizes to setups without these drawbacks. Here, we aimed at establishing the relevance of attributions for decision-making by showing an attribution-related positivity bias in a decision-making task. We developed a novel task, which allowed us to test how participants changed their evaluations in response to positive and negative feedback about performance. Specifically, we used videos of actors expressing different facial emotional expressions. Participants were first asked to evaluate the actors’ credibility in expressing a particular emotion. After this initial rating, participants performed an emotion recognition task and did—or did not—receive feedback on their veridical performance. Finally, participants re-rated the actors’ credibility, which provided a measure of how they changed their evaluations after feedback. Attribution theory predicts that participants change their evaluations of the actors’ credibility toward the positive after receiving positive performance feedback and toward the negative after negative performance feedback. Our results were in line with this prediction. A control condition without feedback showed that correct or incorrect

  19. Accuracy of three-dimensional soft tissue prediction for Le Fort I osteotomy using Dolphin 3D software: a pilot study.

    PubMed

    Resnick, C M; Dang, R R; Glick, S J; Padwa, B L

    2017-03-01

    Three-dimensional (3D) soft tissue prediction is replacing two-dimensional analysis in planning for orthognathic surgery. The accuracy of different computational models to predict soft tissue changes in 3D, however, is unclear. A retrospective pilot study was implemented to assess the accuracy of Dolphin 3D software in making these predictions. Seven patients who had a single-segment Le Fort I osteotomy and had preoperative (T0) and >6-month postoperative (T1) cone beam computed tomography (CBCT) scans and 3D photographs were included. The actual skeletal change was determined by subtracting the T0 from the T1 CBCT. 3D photographs were overlaid onto the T0 CBCT and virtual skeletal movements equivalent to the achieved repositioning were applied using Dolphin 3D planner. A 3D soft tissue prediction (TP) was generated and differences between the TP and T1 images (error) were measured at 14 points and at the nasolabial angle. A mean linear prediction error of 2.91±2.16mm was found. The mean error at the nasolabial angle was 8.1±5.6°. In conclusion, the ability to accurately predict 3D soft tissue changes after Le Fort I osteotomy using Dolphin 3D software is limited.

  20. Accuracy of imaging parameters in the prediction of lethal pulmonary hypoplasia secondary to mid-trimester prelabor rupture of fetal membranes: a systematic review and meta-analysis.

    PubMed

    van Teeffelen, A S P; Van Der Heijden, J; Oei, S G; Porath, M M; Willekes, C; Opmeer, B; Mol, B W J

    2012-05-01

    In women who have suffered mid-trimester prelabor rupture of membranes (PPROM), prediction of pulmonary hypoplasia is important for optimal management. We performed a systematic review to assess the capacity of imaging parameters to predict pulmonary hypoplasia. We searched for published articles that reported on biometric parameters and allowed the construction of a 2 × 2 table, comparing at least one of these parameters with the occurrence of pulmonary hypoplasia. The selected studies were scored on methodological quality and we calculated sensitivity and specificity of the tests in the prediction of pulmonary hypoplasia and lethal pulmonary hypoplasia. Overall performance was assessed by summary receiver-operating characteristics (sROC) analyses that were performed with bivariate meta-analysis. We detected 13 studies that reported on the prediction of lethal pulmonary hypoplasia. The quality of the included studies was poor to mediocre. The estimated sROC curves for the chest circumference/abdominal circumference ratio and other parameters showed limited accuracy in the prediction of pulmonary hypoplasia. In women with mid-trimester PPROM, the available evidence indicates limited accuracy of biometric parameters in the prediction of pulmonary hypoplasia.

  1. Analysis of the Ship Ops Model’s Accuracy in Predicting U.S. Naval Ship Operating Cost

    DTIC Science & Technology

    2003-06-01

    AGENCY REPORT NUMBER 11. SUPPLEMENTARY NOTES The views expressed in this report are those of the author(s) and do not reflect the official policy or...Dean Graduate School of Business and Public Policy iv THIS PAGE INTENTIONALLY LEFT BLANK v ANALYSIS OF THE SHIP OPS MODEL’S ACCURACY...of Model Accuracy using backcast : 1997-2002 Year SF SU SR SO Total 1997 $24,654 $4,315 $12,748 $6,626 $48,343 1998 $29,890 $5,853 $15,300 $9,046

  2. Adaptability and Prediction of Anticipatory Muscular Activity Parameters to Different Movements in the Sitting Position.

    PubMed

    Chikh, Soufien; Watelain, Eric; Faupin, Arnaud; Pinti, Antonio; Jarraya, Mohamed; Garnier, Cyril

    2016-08-01

    Voluntary movement often causes postural perturbation that requires an anticipatory postural adjustment to minimize perturbation and increase the efficiency and coordination during execution. This systematic review focuses specifically on the relationship between the parameters of anticipatory muscular activities and movement finality in sitting position among adults, to study the adaptability and predictability of anticipatory muscular activities parameters to different movements and conditions in sitting position in adults. A systematic literature search was performed using PubMed, Science Direct, Web of Science, Springer-Link, Engineering Village, and EbscoHost. Inclusion and exclusion criteria were applied to retain the most rigorous and specific studies, yielding 76 articles, Seventeen articles were excluded at first reading, and after the application of inclusion and exclusion criteria, 23 were retained. In a sitting position, central nervous system activity precedes movement by diverse anticipatory muscular activities and shows the ability to adapt anticipatory muscular activity parameters to the movement direction, postural stability, or charge weight. In addition, these parameters could be adapted to the speed of execution, as found for the standing position. Parameters of anticipatory muscular activities (duration, order, and amplitude of muscle contractions constituting the anticipatory muscular activity) could be used as a predictive indicator of forthcoming movement. In addition, this systematic review may improve methodology in empirical studies and assistive technology for people with disabilities.

  3. Prediction of positive food effect: Bioavailability enhancement of BCS class II drugs.

    PubMed

    Raman, Siddarth; Polli, James E

    2016-06-15

    High-throughput screening methods have increased the number of poorly water-soluble, highly permeable drug candidates. Many of these candidates have increased bioavailability when administered with food (i.e., exhibit a positive food effect). Food is known to impact drug bioavailability through a variety of mechanisms, including drug solubilization and prolonged gastric residence time. In vitro dissolution media that aim to mimic in vivo gastrointestinal (GI) conditions have been developed to lessen the need for fed human bioequivalence studies. The objective of this work was to develop an in vitro lipolysis model to predict positive food effect of three BCS Class II drugs (i.e., danazol, amiodarone and ivermectin) in previously developed lipolysis media. This in vitro lipolysis model was comparatively benchmarked against FeSSIF and FaSSIF media that were modified for an in vitro lipolysis approach, as FeSSIF and FaSSIF are widely used in in vitro dissolution studies. The in vitro lipolysis