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Sample records for assay improves accuracy

  1. Accuracy of FVIII: C assay by one-stage method can be improved using hemophilic plasma as diluent.

    Science.gov (United States)

    Cinotti, S; Paladino, E; Morfini, M

    2006-04-01

    the basic prerequisite of Factor VIII clotting assay (FVIII:C) by One-Stage Method is that all other than FVIII clotting factors are present in constant concentration in each dilution of both standard reference and patient's plasma curves. On the contrary, the plasma content of each dilution is decreasing as the dilution factor increases. to keep exactly constant the plasma content in each mixture, we performed all dilutions of both standard reference and patient's plasma with FVIII deficient plasma and further with a fixed amount of buffer (method B). To show the discrepancies between this method and regular method A, using buffer to make dilutions, a comparative study was conducted on FVIII: C assay on samples at known FVIII concentration and in patients' plasma. Imidazole or Owren's buffers and five different aPTT reagents were employed, both in method A and B. a discrepancy between FVIII: C assays obtained by method A and B was observed, mainly when Pathrontin SL and Imidazole buffer were used. The assays derived from method B always better fit with the expected, calculated, values of FVIII:C concentrations. Furthermore, FVIII: C was assayed in 60 patients: the outcome of method A was always higher than values of method B. The discrepancy between the two methods was higher at FVIII concentrations below 50 U/dL but null at 100 U/dL. The A slope was steeper than B slope and the difference was statistically significant starting from the 1/10 dilution. Accordingly, FVIII: C of patients' plasma obtained by method A was always higher that those obtained by method B, even 2 or 3 times for FVIII level < or = 10 U/dL or 1.4-1.6 times for FVIII levels between 10 and 25 U/dL. only method B is able to give FVIII: C assays in agreement with the expected values. The dilution of reference standards and samples with FVIII deficient plasma is crucial to accurately evaluate the post-infusion FVIII concentrations in pharmacokinetic studies or the trough level during prophylactic

  2. Cadastral Database Positional Accuracy Improvement

    Science.gov (United States)

    Hashim, N. M.; Omar, A. H.; Ramli, S. N. M.; Omar, K. M.; Din, N.

    2017-10-01

    Positional Accuracy Improvement (PAI) is the refining process of the geometry feature in a geospatial dataset to improve its actual position. This actual position relates to the absolute position in specific coordinate system and the relation to the neighborhood features. With the growth of spatial based technology especially Geographical Information System (GIS) and Global Navigation Satellite System (GNSS), the PAI campaign is inevitable especially to the legacy cadastral database. Integration of legacy dataset and higher accuracy dataset like GNSS observation is a potential solution for improving the legacy dataset. However, by merely integrating both datasets will lead to a distortion of the relative geometry. The improved dataset should be further treated to minimize inherent errors and fitting to the new accurate dataset. The main focus of this study is to describe a method of angular based Least Square Adjustment (LSA) for PAI process of legacy dataset. The existing high accuracy dataset known as National Digital Cadastral Database (NDCDB) is then used as bench mark to validate the results. It was found that the propose technique is highly possible for positional accuracy improvement of legacy spatial datasets.

  3. Improving Speaking Accuracy through Awareness

    Science.gov (United States)

    Dormer, Jan Edwards

    2013-01-01

    Increased English learner accuracy can be achieved by leading students through six stages of awareness. The first three awareness stages build up students' motivation to improve, and the second three provide learners with crucial input for change. The final result is "sustained language awareness," resulting in ongoing…

  4. Improving Accuracy of Processing Through Active Control

    Directory of Open Access Journals (Sweden)

    N. N. Barbashov

    2016-01-01

    Full Text Available An important task of modern mathematical statistics with its methods based on the theory of probability is a scientific estimate of measurement results. There are certain costs under control, and under ineffective control when a customer has got defective products these costs are significantly higher because of parts recall.When machining the parts, under the influence of errors a range scatter of part dimensions is offset towards the tolerance limit. To improve a processing accuracy and avoid defective products involves reducing components of error in machining, i.e. to improve the accuracy of machine and tool, tool life, rigidity of the system, accuracy of the adjustment. In a given time it is also necessary to adapt machine.To improve an accuracy and a machining rate there, currently  become extensively popular various the in-process gaging devices and controlled machining that uses adaptive control systems for the process monitoring. Improving the accuracy in this case is compensation of a majority of technological errors. The in-cycle measuring sensors (sensors of active control allow processing accuracy improvement by one or two quality and provide a capability for simultaneous operation of several machines.Efficient use of in-cycle measuring sensors requires development of methods to control the accuracy through providing the appropriate adjustments. Methods based on the moving average, appear to be the most promising for accuracy control since they include data on the change in some last measured values of the parameter under control.

  5. Improving the accuracy of computed matrix eigenvalues

    Energy Technology Data Exchange (ETDEWEB)

    Dongarra, J J

    1980-08-01

    A computational method is described for improving the accuracy of a given eigenvalue and its associated eigenvector, arrived at through a computation in a lower precision. The method to be described will increase the accuracy of the pair and do so at a relatively low cost. The technique used is similar to iterative refinement for the solution of a linear system; that is, through the factorization from the low-precision computation, an iterative algorithm is applied to increase the accuracy of the eigenpair. Extended precision arithmetic is used at critical points in the algorithm. The iterative algorithm requires O(n/sup 2/) operations for each iteration.

  6. Evaluation of the accuracy of antioxidant competition assays: incorrect assumptions with major impact.

    Science.gov (United States)

    Balk, Jiska M; Bast, Aalt; Haenen, Guido R M M

    2009-07-15

    The activity of antioxidants is frequently determined in competition assays. In these assays an antioxidant (A) and a detector molecule (D) compete for the reactive species (R). The competitive inhibitory effect of A on the reaction of D with R is a measure of the antioxidant activity of A. In determining the activity of A, it is in general incorrectly assumed that the concentrations of A and D remain equal to the initial concentration. However, the principle of the assay is that some A and D is consumed and consequently the concentrations of A and D will decrease during a competition assay, resulting in a deviation in the observed antioxidant activity. Computer modeling was used to obtain a graphical tool to estimate the extent of the deviation caused by the incorrect assumption that the concentrations of A and D do not decrease. Several competition assays were evaluated using this graphical tool, demonstrating that frequently inaccurate antioxidant activities have been reported. In general, differences between antioxidants are underestimated and the activity of all antioxidants shifts toward the antioxidant activity of D. A strategy is provided to improve the accuracy of a competition assay. To obtain accurate results in a competition assay, the reaction rate constant of the detector molecule with the reactive species should be comparable to that of the antioxidant. In addition, the concentration of the reactive species should be as low as possible.

  7. Improving the accuracy of dynamic mass calculation

    Directory of Open Access Journals (Sweden)

    Oleksandr F. Dashchenko

    2015-06-01

    Full Text Available With the acceleration of goods transporting, cargo accounting plays an important role in today's global and complex environment. Weight is the most reliable indicator of the materials control. Unlike many other variables that can be measured indirectly, the weight can be measured directly and accurately. Using strain-gauge transducers, weight value can be obtained within a few milliseconds; such values correspond to the momentary load, which acts on the sensor. Determination of the weight of moving transport is only possible by appropriate processing of the sensor signal. The aim of the research is to develop a methodology for weighing freight rolling stock, which increases the accuracy of the measurement of dynamic mass, in particular wagon that moves. Apart from time-series methods, preliminary filtration for improving the accuracy of calculation is used. The results of the simulation are presented.

  8. Mutants of Cre recombinase with improved accuracy

    Science.gov (United States)

    Eroshenko, Nikolai; Church, George M.

    2013-01-01

    Despite rapid advances in genome engineering technologies, inserting genes into precise locations in the human genome remains an outstanding problem. It has been suggested that site-specific recombinases can be adapted towards use as transgene delivery vectors. The specificity of recombinases can be altered either with directed evolution or via fusions to modular DNA-binding domains. Unfortunately, both wildtype and altered variants often have detectable activities at off-target sites. Here we use bacterial selections to identify mutations in the dimerization surface of Cre recombinase (R32V, R32M, and 303GVSdup) that improve the accuracy of recombination. The mutants are functional in bacteria, in human cells, and in vitro (except for 303GVSdup, which we did not purify), and have improved selectivity against both model off-target sites and the entire E. coli genome. We propose that destabilizing binding cooperativity may be a general strategy for improving the accuracy of dimeric DNA-binding proteins. PMID:24056590

  9. Accuracy of a prey-specific DNA assay and a generic prey-immunomarking assay for detecting predation

    Science.gov (United States)

    1. Predator gut examinations are useful for detecting arthropod predation events. Here, the accuracy and reproducibility of two different types of gut assays are tested on various predator species that consumed an immature lacewing, Chrysoperla carnea (Stephens), that was externally labelled with ra...

  10. Improving Accuracy of Image Classification Using GIS

    Science.gov (United States)

    Gupta, R. K.; Prasad, T. S.; Bala Manikavelu, P. M.; Vijayan, D.

    The Remote Sensing signal which reaches sensor on-board the satellite is the complex aggregation of signals (in agriculture field for example) from soil (with all its variations such as colour, texture, particle size, clay content, organic and nutrition content, inorganic content, water content etc.), plant (height, architecture, leaf area index, mean canopy inclination etc.), canopy closure status and atmospheric effects, and from this we want to find say, characteristics of vegetation. If sensor on- board the satellite makes measurements in n-bands (n of n*1 dimension) and number of classes in an image are c (f of c*1 dimension), then considering linear mixture modeling the pixel classification problem could be written as n = m* f +, where m is the transformation matrix of (n*c) dimension and therepresents the error vector (noise). The problem is to estimate f by inverting the above equation and the possible solutions for such problem are many. Thus, getting back individual classes from satellite data is an ill-posed inverse problem for which unique solution is not feasible and this puts limit to the obtainable classification accuracy. Maximum Likelihood (ML) is the constraint mostly practiced in solving such a situation which suffers from the handicaps of assumed Gaussian distribution and random nature of pixels (in-fact there is high auto-correlation among the pixels of a specific class and further high auto-correlation among the pixels in sub- classes where the homogeneity would be high among pixels). Due to this, achieving of very high accuracy in the classification of remote sensing images is not a straight proposition. With the availability of the GIS for the area under study (i) a priori probability for different classes could be assigned to ML classifier in more realistic terms and (ii) the purity of training sets for different thematic classes could be better ascertained. To what extent this could improve the accuracy of classification in ML classifier

  11. Evaluating the diagnostic accuracy of the Xpert®MTB/RIF assay on bronchoalveolar lavage fluid: a retrospective study.

    Science.gov (United States)

    Lu, Yanjun; Zhu, Yaowu; Shen, Na; Tian, Lei; Sun, Ziyong

    2018-02-08

    Limited data on the diagnostic accuracy of the Xpert ® MTB/RIF assay using bronchoalveolar lavage fluid in patients with suspected pulmonary tuberculosis (PTB) have been reported in China. Therefore, we designed a retrospective study to evaluate the diagnostic accuracy of this assay. Clinical, radiological, and microbiological characteristics of 238 PTB-suspected patients were retrospectively reviewed. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the diagnosis of active PTB were calculated for the Xpert ® MTB/RIF assay using TB culture or final diagnosis based on clinical and radiological evaluation as a reference standard. The sensitivity and specificity of the Xpert ® MTB/RIF assay were 84.5% and 98.9%, and those for smear microscopy (SM) were 36.2% and 100%, respectively, when compared with those of the culture method. However, compared with the sensitivity and specificity of final diagnosis based on clinical and radiological evaluation, the sensitivity and specificity of the assay were 72.9% and 98.7%, which were significantly higher than those for SM. The Xpert ® MTB/RIF assay on bronchoalveolar lavage fluid could serve as an additional rapid diagnosis tool for PTB in a high TB-burden country and improve the time to TB treatment initiation in patients with PTB. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  12. Improving Accuracy for Matrix Multiplications on GPUs

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    Matthew Badin

    2011-01-01

    Full Text Available Reproducibility of an experiment is a commonly used metric to determine its validity. Within scientific computing, this can become difficult due to the accumulation of floating point rounding errors in the numerical computation, greatly reducing the accuracy of the computation. Matrix multiplication is particularly susceptible to these rounding errors which is why there exist so many solutions, ranging from simulating extra precision to compensated summation algorithms. These solutions however all suffer from the same problem, abysmal performance when compared against the performance of the original algorithm. Graphics cards are particularly susceptible due to a lack of double precision on all but the most recent generation graphics cards, therefore increasing the accuracy of the precision that is offered becomes paramount. By using our method of selectively applying compensated summation algorithms, we are able to return a whole digit of accuracy on current generation graphics cards and potentially two digits of accuracy on the newly released “fermi” architecture. This is all possible with only a 2% drop in performance.

  13. Creatinine Assay Attainment of Analytical Performance Goals Following Implementation of IDMS Standardization: Further Improvements Required.

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    Lee, Elizabeth Sunmin; Collier, Christine P; White, Christine A

    2017-01-01

    The international initiative to standardize creatinine (Cr) assays by tracing reference materials to Isotope Dilution Mass Spectrometry (IDMS) assigned values was implemented to reduce interlaboratory variability and improve assay accuracy. The aims of this study were to examine whether IDMS standardization has improved Cr assay accuracy (bias), interlaboratory variability (precision), total error (TE), and attainment of recommended analytical performance goals. External Quality Assessment (EQA) data (n = 66 challenge vials) from Ontario, Canada, were analyzed. The bias, precision, TE, and the number of EQA challenge vials meeting performance goals were determined by assay manufacturer before (n = 32) and after (n = 34) IDMS implementation. The challenge vials with the worst bias and precision were spiked with known common interfering substances (glucose and bilirubin). IDMS standardization improved assay bias (10.4%-1.6%, P IDMS standardization has improved Cr assay accuracy and thus reduced TE, significant interlaboratory variability remains. Contemporary Cr assays do not currently meet the standards required to allow for accurate and consistent estimated glomerular filtration rate assessment and chronic kidney disease diagnosis across laboratories. Further improvements in Cr assay performance are needed.

  14. Improving calibration accuracy in gel dosimetry

    Science.gov (United States)

    Oldham, M.; McJury, M.; Baustert, I. B.; Webb, S.; Leach, M. O.

    1998-10-01

    A new method of calibrating gel dosimeters (applicable to both Fricke and polyacrylamide gels) is presented which has intrinsically higher accuracy than current methods, and requires less gel. Two test-tubes of gel (inner diameter 2.5 cm, length 20 cm) are irradiated separately with a field end-on in a water bath, such that the characteristic depth-dose curve is recorded in the gel. The calibration is then determined by fitting the depth-dose measured in water, against the measured change in relaxivity with depth in the gel. Increased accuracy is achieved in this simple depth-dose geometry by averaging the relaxivity at each depth. A large number of calibration data points, each with relatively high accuracy, are obtained. Calibration data over the full range of dose (1.6-10 Gy) is obtained by irradiating one test-tube to 10 Gy at dose maximum , and the other to 4.5 Gy at . The new calibration method is compared with a `standard method' where five identical test-tubes of gel were irradiated to different known doses between 2 and 10 Gy. The percentage uncertainties in the slope and intercept of the calibration fit are found to be lower with the new method by a factor of about 4 and 10 respectively, when compared with the standard method and with published values. The gel was found to respond linearly within the error bars up to doses of 7 Gy, with a slope of and an intercept of Gy. For higher doses, nonlinear behaviour was observed.

  15. Concept Mapping Improves Metacomprehension Accuracy among 7th Graders

    Science.gov (United States)

    Redford, Joshua S.; Thiede, Keith W.; Wiley, Jennifer; Griffin, Thomas D.

    2012-01-01

    Two experiments explored concept map construction as a useful intervention to improve metacomprehension accuracy among 7th grade students. In the first experiment, metacomprehension was marginally better for a concept mapping group than for a rereading group. In the second experiment, metacomprehension accuracy was significantly greater for a…

  16. Accuracy Improvement of Magnetic Hysteresis Calculated by LLG Equation

    Science.gov (United States)

    Tanaka, H.; Nakamura, K.; Ichinokura, O.

    2017-10-01

    Quantitative estimation of iron loss including magnetic hysteresis behavior is essential to the development of high-efficient electrical machines. A simplified micromagnetic model using Landau-Lifshitz-Gilbert (LLG) equation is one of the useful models for calculating the hysteresis behavior. However, further improvement of the calculation accuracy under magnetic saturation is required. This paper presents the accuracy improvement of the magnetic hysteresis calculated by the LLG equation.

  17. Does a Structured Data Collection Form Improve The Accuracy of ...

    African Journals Online (AJOL)

    6. Guerlain S, Lebeau K, Thompson M, et al. The effect of a standardized data collection form on diagnostic accuracy of acute abdominal pain. Human factors. 2001;45:1284–8. 7. Wellwood J, Johannessen S. How does computer- aided diagnosis improve the management of acute abdominal pain ? Ann Roy Coll Surg Engl.

  18. Error analysis to improve the speech recognition accuracy on ...

    Indian Academy of Sciences (India)

    Telugu language is one of the most widely spoken south Indian languages. In the proposed Telugu speech recognition system, errors obtained from decoder are analysed to improve the performance of the speech recognition system. Static pronunciation dictionary plays a key role in the speech recognition accuracy.

  19. A study of the conditions and accuracy of the thrombin time assay of plasma fibrinogen

    DEFF Research Database (Denmark)

    Jespersen, J; Sidelmann, Johannes Jakobsen

    1982-01-01

    The conditions, accuracy, precision and possible error of the thrombin time assay of plasma fibrinogen are determined. Comparison with an estimation of clottable protein by absorbance at 280 nm gave a correlation coefficient of 0.96 and the regression line y = 1.00 x + 0.56 (n = 34). Comparison...... with a radial immunodiffusion method yielded the correlation coefficient 0.97 and the regression line y = 1.18 x = 2.47 (n = 26). The presence of heparin in clinically applied concentrations produced a slight shortening of the clotting times. The resulting error in the estimated concentrations of fibrinogen...... was too small to affect the clinical usefulness of the determinations. The influence of fibrin(ogen) degradation products was significant only in excessive amounts in samples containing low levels of fibrinogen....

  20. Improving Accuracy of Processing by Adaptive Control Techniques

    Directory of Open Access Journals (Sweden)

    N. N. Barbashov

    2016-01-01

    Full Text Available When machining the work-pieces a range of scatter of the work-piece dimensions to the tolerance limit is displaced in response to the errors. To improve an accuracy of machining and prevent products from defects it is necessary to diminish the machining error components, i.e. to improve the accuracy of machine tool, tool life, rigidity of the system, accuracy of adjustment. It is also necessary to provide on-machine adjustment after a certain time. However, increasing number of readjustments reduces the performance and high machine and tool requirements lead to a significant increase in the machining cost.To improve the accuracy and machining rate, various devices of active control (in-process gaging devices, as well as controlled machining through adaptive systems for a technological process control now become widely used. Thus, the accuracy improvement in this case is reached by compensation of a majority of technological errors. The sensors of active control can provide improving the accuracy of processing by one or two quality classes, and simultaneous operation of several machines.For efficient use of sensors of active control it is necessary to develop the accuracy control methods by means of introducing the appropriate adjustments to solve this problem. Methods based on the moving average, appear to be the most promising for accuracy control, since they contain information on the change in the last several measured values of the parameter under control.When using the proposed method in calculation, the first three members of the sequence of deviations remain unchanged, therefore 1 1 x  x , 2 2 x  x , 3 3 x  x Then, for each i-th member of the sequence we calculate that way: , ' i i i x  x  k x , where instead of the i x values will be populated with the corresponding values ' i x calculated as an average of three previous members:3 ' 1  2  3  i i i i x x x x .As a criterion for the estimate of the control

  1. The diagnostic accuracy of pericardial and urinary lipoarabinomannan (LAM) assays in patients with suspected tuberculous pericarditis.

    Science.gov (United States)

    Pandie, Shaheen; Peter, Jonathan G; Kerbelker, Zita S; Meldau, Richard; Theron, Grant; Govender, Ureshnie; Ntsekhe, Mpiko; Dheda, Keertan; Mayosi, Bongani M

    2016-09-16

    We evaluated the diagnostic accuracy of urinary and pericardial fluid (PF) lipoarabinomannan (LAM) assays in tuberculous pericarditis (TBP). From October 2009 through September 2012, 151 patients with TBP were enrolled. Mycobacterium tuberculosis culture and/or pericardial histology were the reference standard for definite TBP. 49% (74/151), 33.1% (50/151) and 17.9% (27/151) of patients had definite-, probable-, and non-TB respectively; 69.5% (105/151) were HIV positive. LAM ELISA had the following sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value and negative predictive values (95% confidence interval): urinary - 17.4% (9.1-30.7), 93.8% (71.7-98.9), 2.8 (0.1-63.3), 0.9 (0.8-0.9), 88.9% (56.5-98.0), and 28.3% (17.9-41.6); PF - 11.6% (6.0-21.3), 88% (70.0-95.8), 0.9 (0.08-12.0), 1.0 (0.9-1.1), 72.7% (43.4-90.1), and 26.6% (18.2-36.9). Sensitivity increased with a CD4 ≤ 100 cells/mm(3) from 3.5% to 50% (p LAM ELISA; for urinary LAM strip test, grade 1 and 2 cut-points performed similarly, irrespective of HIV status or CD4 count. For PF LAM strip tests, switching cut-points from grade 1 to 2 significantly reduced test sensitivity (54.5% versus 19.7%; p LAM assays have low sensitivity but high specificity for diagnosis of TBP. The sensitivity of urinary LAM is increased in HIV-infected patients with a CD4 ≤ 100 cells/mm(3).

  2. Improving IMES Localization Accuracy by Integrating Dead Reckoning Information

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    Kenjiro Fujii

    2016-01-01

    Full Text Available Indoor positioning remains an open problem, because it is difficult to achieve satisfactory accuracy within an indoor environment using current radio-based localization technology. In this study, we investigate the use of Indoor Messaging System (IMES radio for high-accuracy indoor positioning. A hybrid positioning method combining IMES radio strength information and pedestrian dead reckoning information is proposed in order to improve IMES localization accuracy. For understanding the carrier noise ratio versus distance relation for IMES radio, the signal propagation of IMES radio is modeled and identified. Then, trilateration and extended Kalman filtering methods using the radio propagation model are developed for position estimation. These methods are evaluated through robot localization and pedestrian localization experiments. The experimental results show that the proposed hybrid positioning method achieved average estimation errors of 217 and 1846 mm in robot localization and pedestrian localization, respectively. In addition, in order to examine the reason for the positioning accuracy of pedestrian localization being much lower than that of robot localization, the influence of the human body on the radio propagation is experimentally evaluated. The result suggests that the influence of the human body can be modeled.

  3. Improvement of Diagnostic Accuracy by Standardization in Diuretic Renal Scan

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, In Young; Lee, Dong Soo; Lee, Kyung Han; Chung, June Key; Lee, Myung Chul; Koh, Chang Soon; Kim, Kwang Myung; Choi, Hwang; Choi, Yong [Seoul National University Hospital, Seoul (Korea, Republic of)

    1995-09-15

    We evaluated diagnostic accuracy of diuretic renal scan with standardization in 45 children(107 hydronephrotic kidneys) with 91 diuretic assessments. Sensitivity was 100% specificity was 78%, and accuracy was 84% in 49 hydronephrotic kidneys with standardization. Diuretic renal scan without standardization, sensitivity was 100%, specificity was 38%, and accuracy was 57% in 58 hydronephrotic kidneys. The false-positive results were observed in 25 cases without standardization, and in 8 cases with standardization. In duretic renal scans without standardization, the causes of false-positive results were 10 early injection of lasix before mixing of radioactivity in loplsty, 6 extrarenal pelvis, and 3 immature kidneys of false-positive results were 2 markedly dilated systems postpyeloplsty, 2 etrarenal pevis, 1 immature kidney of neonate , and 2 severe renal dysfunction, 1 vesicoureteral, reflux. In diuretic renal scan without standardization the false-positive results by inadequate study were common, but false-positive results by inadequate study were not found after standardization. The false-positive results by dilated pelvo-calyceal systems postpyeloplsty, extrarenal pelvis, and immature kidneys of, neonates were not dissolved after standardization. In conclusion, diagnostic accuracy of diuretic renal scan with standardization was useful in children with renal outflow tract obstruction by improving specificity significantly.

  4. Improving IMES Localization Accuracy by Integrating Dead Reckoning Information.

    Science.gov (United States)

    Fujii, Kenjiro; Arie, Hiroaki; Wang, Wei; Kaneko, Yuto; Sakamoto, Yoshihiro; Schmitz, Alexander; Sugano, Shigeki

    2016-01-27

    Indoor positioning remains an open problem, because it is difficult to achieve satisfactory accuracy within an indoor environment using current radio-based localization technology. In this study, we investigate the use of Indoor Messaging System (IMES) radio for high-accuracy indoor positioning. A hybrid positioning method combining IMES radio strength information and pedestrian dead reckoning information is proposed in order to improve IMES localization accuracy. For understanding the carrier noise ratio versus distance relation for IMES radio, the signal propagation of IMES radio is modeled and identified. Then, trilateration and extended Kalman filtering methods using the radio propagation model are developed for position estimation. These methods are evaluated through robot localization and pedestrian localization experiments. The experimental results show that the proposed hybrid positioning method achieved average estimation errors of 217 and 1846 mm in robot localization and pedestrian localization, respectively. In addition, in order to examine the reason for the positioning accuracy of pedestrian localization being much lower than that of robot localization, the influence of the human body on the radio propagation is experimentally evaluated. The result suggests that the influence of the human body can be modeled.

  5. Method for Improving Indoor Positioning Accuracy Using Extended Kalman Filter

    Directory of Open Access Journals (Sweden)

    Seoung-Hyeon Lee

    2016-01-01

    Full Text Available Beacons using bluetooth low-energy (BLE technology have emerged as a new paradigm of indoor positioning service (IPS because of their advantages such as low power consumption, miniaturization, wide signal range, and low cost. However, the beacon performance is poor in terms of the indoor positioning accuracy because of noise, motion, and fading, all of which are characteristics of a bluetooth signal and depend on the installation location. Therefore, it is necessary to improve the accuracy of beacon-based indoor positioning technology by fusing it with existing indoor positioning technology, which uses Wi-Fi, ZigBee, and so forth. This study proposes a beacon-based indoor positioning method using an extended Kalman filter that recursively processes input data including noise. After defining the movement of a smartphone on a flat two-dimensional surface, it was assumed that the beacon signal is nonlinear. Then, the standard deviation and properties of the beacon signal were analyzed. According to the analysis results, an extended Kalman filter was designed and the accuracy of the smartphone’s indoor position was analyzed through simulations and tests. The proposed technique achieved good indoor positioning accuracy, with errors of 0.26 m and 0.28 m from the average x- and y-coordinates, respectively, based solely on the beacon signal.

  6. Evidence that Indirect Inhibition of Saccade Initiation Improves Saccade Accuracy

    Directory of Open Access Journals (Sweden)

    Eugene McSorley

    2010-08-01

    Full Text Available Saccadic eye-movements to a visual target are less accurate if there are distracters close to its location (local distracters. The addition of more distracters, remote from the target location (remote distracters, invokes an involuntary increase in the response latency of the saccade and attenuates the effect of local distracters on accuracy. This may be due to the target and distracters directly competing (direct route or to the remote distracters acting to impair the ability to disengage from fixation (indirect route. To distinguish between these, we examined the development of saccade competition by recording saccade latency and accuracy responses made to a target and local distracter compared with those made with an addition of a remote distracter. The direct route would predict that the remote distracter impacts on the developing competition between target and local distracter, while the indirect route would predict no change as the accuracy benefit here derives from accessing the same competitive process but at a later stage. We found that the presence of the remote distracter did not change the pattern of accuracy improvement. This suggests that the remote distracter was acting along an indirect route that inhibits disengagement from fixation, slows saccade initiation, and enables more accurate saccades to be made.

  7. Accuracy of self-collected vaginal dry swabs using the Xpert human papillomavirus assay.

    Directory of Open Access Journals (Sweden)

    Rosa Catarino

    Full Text Available Polymerase chain reaction-based Xpert human papillomavirus (HPV assay is a rapid test that detects high-risk HPV (hrHPV infection. This point-of-care test is usually performed by collecting a cervical specimen in a vial of PreservCyt® transport medium. We compared HPV test positivity and accuracy between self-collected sample with a dry swab (s-DRY versus physician-collected cervical sampling using a broom like brush and immediate immersion in PreservCyt (dr-WET.In this cross-sectional study, we recruited 150 women ≥ 18 years old attending the colposcopy clinic in the University Hospital of Geneva. Each participant first self-collected a vaginal sample using a dry swab and then the physician collected a cervical specimen in PreservCyt. HPV analysis was performed with Xpert. Part of the PreservCyt-collected sample was used for hrHPV detection with the cobas® HPV test. HPV test positivity and performance of the two collection methods was compared.HPV positivity was 49.1% for s-DRY, 41.8% for dr-WET and 46.2% for cobas. Good agreement was found between s-DRY and dr-WET samples (kappa±Standard error (SE = 0.64±0.09,, particularly for low-grade squamous intraepithelial lesions (LSIL+ (kappa±SE = 0.80±0.17. Excellent agreement was found between the two samples for HPV16 detection in general (kappa±SE = 0.91±0.09 and among LSIL+ lesions (kappa±SE = 1.00±0.17. Sensitivities and specificities were, respectively, 84.2% and 47.1%(s-DRY, 73.1% and 58.7%. (dr-WET and 77.8% and 45.7% (cobas for CIN2+ detection. The median delay between sampling and HPV analysis was 7 days for the Xpert HPV assay and 19 days for cobas. There were 36 (24.0% invalid results among s-DRY samples and 4 (2.7% among dr-WET (p = 0.001. Invalid results happened due to the long interval between collection and analysis.Self-collected vaginal dry swabs are a valid alternative to collecting cervical samples in PreservCyt solution for HPV testing with the Xpert HPV assay

  8. Improvements in Mass Spectrometry Assay Library Generation for Targeted Proteomics.

    Science.gov (United States)

    Teleman, Johan; Hauri, Simon; Malmström, Johan

    2017-07-07

    In data-independent acquisition mass spectrometry (DIA-MS), targeted extraction of peptide signals in silico using mass spectrometry assay libraries is a successful method for the identification and quantification of proteins. However, it remains unclear if high quality assay libraries with more accurate peptide ion coordinates can improve peptide target identification rates in DIA analysis. In this study, we systematically improved and evaluated the common algorithmic steps for assay library generation and demonstrate that increased assay quality results in substantially higher identification rates of peptide targets from mouse organ protein lysates measured by DIA-MS. The introduced changes are (1) a new spectrum interpretation algorithm, (2) reapplication of segmented retention time normalization, (3) a ppm fragment mass error matching threshold, (4) usage of internal peptide fragments, and (5) a multilevel false discovery rate calculation. Taken together, these changes yielded 14-36% more identified peptide targets at 1% assay false discovery rate and are implemented in three new open source tools, Fraggle, Tramler, and Franklin, available at https://github.com/fickludd/eviltools . The improved algorithms provide ways to better utilize discovery MS data, translating to substantially increased DIA performance and ultimately better foundations for drawing biological conclusions in DIA-based experiments.

  9. Diagnostic accuracy of a new point-of-care screening assay for celiac disease.

    Science.gov (United States)

    Benkebil, Faiza; Combescure, Christophe; Anghel, Silvia I; Besson Duvanel, Cécile; Schäppi, Michela G

    2013-08-21

    To determine the diagnostic accuracy of a new point-of-care assay detecting anti-deamidated gliadin peptides in celiac disease (CD) patients. One-hundred-and-twelve patients (age range: 1.8-79.2 years old) with clinical symptoms suggestive of CD and/or first-degree relatives (FDR) of CD patients (n = 66), and confirmed CD on a gluten-free diet (GFD) (n = 46), were prospectively enrolled in the study at Gastroenterology outpatient clinics for adult patients and from the Gastroenterology Consultation Ward at the Pediatric Department of the University Hospital of Geneva. Written informed consent was obtained from all subjects enrolled. The study received approval from the local ethics committee. The original CD diagnosis had been based on serum-positive IgA anti-tissue transglutaminase enzyme-linked immunosorbent assay (ELISA) (QuantaLite™, Inova Diagnostics, San Diego, CA, United States) and on biopsy results. Serum samples from all study participants were tested by the new CD lateral flow immunochromatographic assay (CD-LFIA) device, Simtomax® Blood Drop (Augurix SA, BioArk, Monthey, Switzerland) to detect immunoglobulin (Ig)A and IgG antibodies against deamidated gliadin peptides. The diagnostic performance was evaluated using receiver operating characteristic curves with 95%CIs. A cut-off of 2 on the Rann colorimetric scale was used to calculate the device's sensitivity and specificity. CD-LFIA was highly accurate in detecting untreated celiac patients. In the group of patients with CD symptoms and/or FDR, eight new cases of CD were detected by ELISA and biopsy. All of these new cases were also correctly identified by CD-LFIA. The test yielded four false positive and four false negative results. The false positive results were all within the groups with clinical symptoms suggestive of CD and/or FDR, whereas the false negative results were all within the GFD group. The test yeld a sensitivity of 78.9% (95%CI: 54.4-93.9) and specificity of 95.7% (95%CI: 89

  10. Quiet eye training improves accuracy in basketball field goal shooting.

    Science.gov (United States)

    Vickers, Joan N; Vandervies, Ben; Kohut, Christie; Ryley, Brendan

    2017-01-01

    University students (N = 240) were randomly assigned to a quiet eye training (QET) or technical training (TT) group, and their shooting accuracy (%) determined during a pre-, post-, and transfer test in basketball field shooting. Both groups first received lectures on visuomotor processing and the quiet eye (QE), followed by a laboratory in which participants in the QET group were taught how to adopt the QE characteristics of elite free-throw shooters, which stresses optimal gaze control and focus relative to a single target location, while the TT participants were taught elite biomechanics which stresses optimal control of the shooting stance, arms, and hands. Overall, the QET group's accuracy was significantly higher than the TT group, but differences were found due to skill level and defensive pressure. From pre to post, the accuracy of the QET novices increased significantly compared to the TT novices, but declined during transfer. Both the QET and TT intermediates had relatively high accuracy scores during the pre- and posttests, which then declined, as expected, during the transfer test against defensive pressure. However, during transfer the QET group's accuracy remained higher than the TT group and was surprisingly similar to that found in elite competition. It is recommended that novice and intermediate basketball players be taught how to adopt the QE of elite players, rather than learning only the technical/mechanical aspects of shooting. Theoretically, the study is placed within the context of top-down "cognitive control," as proposed by Cavanagh and Frank (2014), and QET studies which show that when learners are taught how to adopt the QE of elite performers, this appears to contribute to a more optimal organization of the neural networks underlying control of the task which, in turn, leads to improved shooting performance. © 2017 Elsevier B.V. All rights reserved.

  11. Pediatric surgeon-directed wound classification improves accuracy.

    Science.gov (United States)

    Zens, Tiffany J; Rusy, Deborah A; Gosain, Ankush

    2016-04-01

    Surgical wound classification (SWC) communicates the degree of contamination in the surgical field and is used to stratify risk of surgical site infection and compare outcomes among centers. We hypothesized that by changing from nurse-directed to surgeon-directed SWC during a structured operative debrief, we will improve accuracy of documentation. An institutional review board-approved retrospective chart review was performed. Two time periods were defined: initially, SWC was determined and recorded by the circulating nurse (before debrief, June 2012-May 2013) and allowing 6 mo for adoption and education, we implemented a structured operative debriefing including surgeon-directed SWC (after debrief, January 2014-August 2014). Accuracy of SWC was determined for four commonly performed pediatric general surgery operations: inguinal hernia repair (clean), gastrostomy ± Nissen fundoplication (clean contaminated), appendectomy without perforation (contaminated), and appendectomy with perforation (dirty). One hundred eighty-three cases before debrief and 142 cases after debrief met inclusion criteria. No differences between time periods were noted in regard to patient demographics, ASA class, or case mix. Accuracy of wound classification improved before debrief (42% versus 58.5%, P = 0.003). Before debrief, 26.8% of cases were overestimated or underestimated by more than one wound class, versus 3.5% of cases after debrief (P wounds and decreases the degree of inaccuracy in incorrectly classified cases. However, after implementation of the debriefing, we still observed a 41.5% rate of incorrect documentation, most notably in contaminated cases, indicating further education and process improvement is needed. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Post-processing for improving hyperspectral anomaly detection accuracy

    Science.gov (United States)

    Wu, Jee-Cheng; Jiang, Chi-Ming; Huang, Chen-Liang

    2015-10-01

    Anomaly detection is an important topic in the exploitation of hyperspectral data. Based on the Reed-Xiaoli (RX) detector and a morphology operator, this research proposes a novel technique for improving the accuracy of hyperspectral anomaly detection. Firstly, the RX-based detector is used to process a given input scene. Then, a post-processing scheme using morphology operator is employed to detect those pixels around high-scoring anomaly pixels. Tests were conducted using two real hyperspectral images with ground truth information and the results based on receiver operating characteristic curves, illustrated that the proposed method reduced the false alarm rates of the RXbased detector.

  13. Improved TLC Bioautographic Assay for Qualitative and Quantitative Estimation of Tyrosinase Inhibitors in Natural Products.

    Science.gov (United States)

    Zhou, Jinge; Tang, Qingjiu; Wu, Tao; Cheng, Zhihong

    2017-03-01

    TLC bioautography for tyrosinase inhibitors has made recent progress; however, an assay with a relative low consumption of enzyme and quantitative capability would greatly advance the efficacy of related TLC bioautographic assays. An improved TLC bioautographic assay for detecting tyrosinase inhibitors was developed and validated in this study. L-DOPA (better water-solubility than L-tyrosine) was used as the substrate instead of reported L-tyrosine. The effects of enzyme and substrate concentrations, reaction temperatures and times, and pH values of the reaction system as well as different plate types on the TLC bioautographic assay were optimised. The quantitative analysis was conducted by densitometric scanning of spot areas, and expressed as the relative tyrosinase inhibitory capacity (RTIC) using a positive control (kojic acid) equivalent. The limit of detection (LOD) of this assay was 1.0 ng for kojic acid. This assay has acceptable accuracy (101.73-102.90%), intra- and inter-day, and intra- and inter-plate precisions [relative standard deviation (RSD), less than 7.0%], and ruggedness (RSD, less than 3.5%). The consumption of enzyme (75 U/mL) is relatively low. Two tyrosinase inhibitory compounds including naringenin and 1-O-β-D-glucopyranosyl-4-allylbenzene have been isolated from Rhodiola sacra guided by this TLC bioautographic assay. Our improved assay is a relatively low-cost, sensitive, and quantitative method compared to the reported TLC bioautographic assays. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  14. MemBrain: improving the accuracy of predicting transmembrane helices.

    Directory of Open Access Journals (Sweden)

    Hongbin Shen

    Full Text Available Prediction of transmembrane helices (TMH in alpha helical membrane proteins provides valuable information about the protein topology when the high resolution structures are not available. Many predictors have been developed based on either amino acid hydrophobicity scale or pure statistical approaches. While these predictors perform reasonably well in identifying the number of TMHs in a protein, they are generally inaccurate in predicting the ends of TMHs, or TMHs of unusual length. To improve the accuracy of TMH detection, we developed a machine-learning based predictor, MemBrain, which integrates a number of modern bioinformatics approaches including sequence representation by multiple sequence alignment matrix, the optimized evidence-theoretic K-nearest neighbor prediction algorithm, fusion of multiple prediction window sizes, and classification by dynamic threshold. MemBrain demonstrates an overall improvement of about 20% in prediction accuracy, particularly, in predicting the ends of TMHs and TMHs that are shorter than 15 residues. It also has the capability to detect N-terminal signal peptides. The MemBrain predictor is a useful sequence-based analysis tool for functional and structural characterization of helical membrane proteins; it is freely available at http://chou.med.harvard.edu/bioinf/MemBrain/.

  15. Accuracy improvement in dissipated energy measurement by using phase information

    Science.gov (United States)

    Shiozawa, D.; Inagawa, T.; Washio, T.; Sakagami, T.

    2017-04-01

    In this paper, a technique for improving the accuracy of a dissipated energy measurement based on the phase information—called the phase 2f lock-in infrared method—is proposed. In the conventional 2f lock-in infrared method, the dissipated energy is obtained as the double frequency component of the measured temperature change. In this work, a phase analysis of the double frequency component has been conducted. It is found that the double frequency component includes the influence of the energy dissipation and harmonic vibration of the fatigue testing machine, and the phase difference between the thermoelastic temperature change and the double frequency component is a specific value. The phase 2f lock-in method utilizes a specific phase of the dissipated energy and is effective for removing the noise component such as the thermoelastic temperature change due to the harmonic vibration of fatigue testing machine. This method provides an improvement in the accuracy of the fatigue-limit estimate and the detection of future crack initiation points based on the dissipated energy.

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

    Science.gov (United States)

    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.

  17. Improving the Accuracy of High-Order Nodal Transport Methods

    Energy Technology Data Exchange (ETDEWEB)

    Azmy, Y.Y.; Buscaglia, G.C.; Zamonsky, O.M.

    1999-09-27

    This paper outlines some recent advances towards improving the accuracy of neutron transport calculations using the Arbitrarily High Order Transport-Nodal (AHOT-N) Method. These advances consist of several contributions: (a) A formula for the spatial weights that allows for the polynomial order to be raised arbitrarily high without suffering adverse effects from round-off error; (b) A reconstruction technique for the angular flux, based upon a recursive formula, that reduces the pointwise error by one ordeq (c) An a posterior error indicator that estimates the true error and its distribution throughout the domain, so that it can be used for adaptively refining the approximation. Present results are mainly for ID, extension to 2D-3D is in progress.

  18. Improving the Accuracy of High-Order Nodal Transport Methods

    Energy Technology Data Exchange (ETDEWEB)

    Azmy, Y.Y.; Buscaglia, G.C.; Zamonsky, O.M.

    1999-09-27

    This paper outlines some recent advances towards improving the accuracy of neutron calculations using the Arbitrarily High Order Transport-Nodal (AHOT-N) Method. These transport advances consist of several contributions: (a) A formula for the spatial weights that allows for the polynomial order to be raised arbitrarily high without suffering from pollution from round-off, error; (b) A reconstruction technique for the angular flux, based upon a recursive formula, that reduces the pointwise error by one order; (c) An a posterior error indicator that estimates the true error and its distribution throughout the domain, so that it can be used for adaptively reftig the approximation. Present results are mainly for ID, extension to 2D-3D is in progress.

  19. Defining cell culture conditions to improve human norovirus infectivity assays

    Energy Technology Data Exchange (ETDEWEB)

    Straub, Tim M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hutchison, Janine R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bartholomew, Rachel A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Valdez, Catherine O. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Valentine, Nancy B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dohnalkova, Alice [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ozanich, Richard M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bruckner-Lea, Cindy J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-01-10

    Significant difficulties remain for determining whether human noroviruses (hNoV) recovered from water, food, and environmental samples are infectious. Three-dimensional tissue culture of human intestinal cells has shown promise in developing an infectivity assay, but reproducibility, even within a single laboratory, remains problematic. From the literature and our observations, we hypothesized that the common factors that leads to more reproducible hNoV infectivity in vitro requires that the cell line be 1) of human gastrointestinal origin, 2) expresses apical microvilli, and 3) be a positive secretor cell line. The C2BBe1 cell line, which is a brush-border producing clone of Caco-2, meets these three criteria. When challenged with Genogroup II viruses, we observed a 2 Log10 increase in viral RNA titer. A passage experiment with GII viruses showed evidence of the ability to propagate hNoV by both reverse transcription quantitative PCR (qRT-PCR) and microscopy. Using 3-D C2BBe1 cells improves reproducibility of the infectivity assay for hNoV, but the assay can still be variable. Two sources of variability include the cells themselves (mixed phenotypes of small and large intestine) and initial titer measurements using quantitative reverse transcription PCR (qRT-PCR) that measures all RNA vs. plaque assays that measure infectious virus.

  20. Analytical Tools to Improve Optimization Procedures for Lateral Flow Assays.

    Science.gov (United States)

    Hsieh, Helen V; Dantzler, Jeffrey L; Weigl, Bernhard H

    2017-05-28

    Immunochromatographic or lateral flow assays (LFAs) are inexpensive, easy to use, point-of-care medical diagnostic tests that are found in arenas ranging from a doctor's office in Manhattan to a rural medical clinic in low resource settings. The simplicity in the LFA itself belies the complex task of optimization required to make the test sensitive, rapid and easy to use. Currently, the manufacturers develop LFAs by empirical optimization of material components (e.g., analytical membranes, conjugate pads and sample pads), biological reagents (e.g., antibodies, blocking reagents and buffers) and the design of delivery geometry. In this paper, we will review conventional optimization and then focus on the latter and outline analytical tools, such as dynamic light scattering and optical biosensors, as well as methods, such as microfluidic flow design and mechanistic models. We are applying these tools to find non-obvious optima of lateral flow assays for improved sensitivity, specificity and manufacturing robustness.

  1. Altered sensory input improves the accuracy of muscle reinnervation.

    Science.gov (United States)

    Skouras, Emmanouil; Popratiloff, Anastas; Guntinas-Lichius, Orlando; Streppel, Michael; Rehm, Klaus E; Neiss, Wolfram F; Angelov, Doychin N

    2002-01-01

    To improve functional recovery after peripheral nerve suture, we characterized the quality of target reinnervation in rats in which the afferent trigeminal connection to facial motoneurons had been altered. Employing an improved lesion model and a refined mode of retrograde tracer application, we studied the accuracy of reinnervation in rats which underwent buccal-buccal nerve anastomosis (BBA) alone (group 1), BBA plus excision of the ipsilateral infraorbital nerve (ION; group 2), and BBA plus excision of the contralateral ION (group 3). This was done by comparison between the number of double-labeled motoneurons after pre-operative injection of Fluoro-Gold (FG) and post-operative injection of Fast Blue (FB) into the whisker pad muscles. In the first group we counted 398 +/- 80 FG+FB double labeled cells (mean +/- SD; n = 9 rats), i.e., only 27% of all motoneurons that grew axons into the whisker pad had projected to these muscles before surgery. In group 2, this value was increased marginally to 436 +/- 68 (32%). In group 3,. we counted 580 +/- 63 double-labeled neurons. This is the first morphological report demonstrating significantly improved specificity of reinnervation. Indeed, 41% of the motoneurons innervating the target in group 3 belonged to the original neuron pool. These morphological findings are supported by evidence obtained from electrophysiological recordings and behavioural studies. The principle finding of the present study is that a peripheral lesion to the contralateral trigeminal nerve improves the quality of reinnervation of the whisker pad musculature by its original nerve. The contralateral trigeminal lesion may trigger behavioural demand and forced overuse of the axotomized facial nerve, which may be a key issue for recovery of vibrissae rhythmical whisking after facial nerve surgery.

  2. Glacier Mapping With Landsat Tm: Improvements and Accuracy

    Science.gov (United States)

    Paul, F.; Huggel, C.; Kaeaeb, A.; Maisch, M.

    The new Swiss Glacier Inventory for the year 2000 (SGI 2000) is presently derived from Landsat TM data. Glacier areas were obtained by segmentation of a ratio image from TM band 4 and 5. This method has proven to be very simple and highly accurate - an essential requirement for world-wide application within the project GLIMS (Global Land Ice Measurements from Space). Mis-classification using TM4 / TM 5 results for lakes, forests and areas with vegetation in cloud shadows. Digital image processing techniques are used to classify these regions separately and eliminate them from the glacier map. Automatic mapping of debris-covered glacier ice is difficult due to the spectral similarity with the surrounding terrain. For the SGI 2000, an attempt has been made to obtain the debris-covered area on glaciers by a combination of pixel- based image classification, digital terrain modelling, an object-oriented procedure and change detection analysis. First results of these improvements are presented. The accuracy of the TM derived glacier outlines is assessed by a comparison with manually derived outlines of higher resolution data sets (pan bands from SPOT, IRS- 1C and Ikonos). The overlay of outlines show very good correspondence (within the georeferencing accuracy) and the comparison of glacier areas reveals differences smaller than 5% for debris-free ice. Since acquisition of IRS-1C and Ikonos imagery is one year before and after the TM scene, respectively, small differences are also a result of glacier retreat. The automatically mapped debris-covered glacier areas are compared to the areas assigned manually on the TM image by visual interpretation. For most glaciers only a few pixels have to be corrected, for some others larger modi- fications are required.

  3. Accuracy of serological assays for detection of recent infection with HIV and estimation of population incidence: a systematic review.

    Science.gov (United States)

    Guy, Rebecca; Gold, Judy; Calleja, Jesus M García; Kim, Andrea A; Parekh, Bharat; Busch, Michael; Rehle, Thomas; Hargrove, John; Remis, Robert S; Kaldor, John M

    2009-12-01

    We systematically reviewed the accuracy of serological tests for recent infections with HIV that have become widely used for measuring population patterns incidence of HIV. Across 13 different assays, sensitivity to detect recent infections ranged from 42-100% (median 89%). Specificity for detecting established infections was between 49.5% and 100% (median 86.8%) and was higher for infections of durations longer than 1 year (median 98%, range 31.5-100.0). For four different assays, comparisons were made between assay-derived population incidence estimates and a reference incidence estimate. The median percentage difference between the assay-derived incidence and reference incidence was 26.0%. Serological assays have reasonable sensitivity for the detection of recent infection with HIV, but are vulnerable to misclassifying established infections as recent-potentially leading to biases in incidence estimates. This conclusion is highly qualified by the apparent absence of a standardised approach to assay evaluation. There is an urgent need for an internationally agreed framework for evaluating and comparing these tests.

  4. Measurement of phospholipids may improve diagnostic accuracy in ovarian cancer.

    Directory of Open Access Journals (Sweden)

    Lian Shan

    Full Text Available BACKGROUND: More than two-thirds of women who undergo surgery for suspected ovarian neoplasm do not have cancer. Our previous results suggest phospholipids as potential biomarkers of ovarian cancer. In this study, we measured the serum levels of multiple phospholipids among women undergoing surgery for suspected ovarian cancer to identify biomarkers that better predict whether an ovarian mass is malignant. METHODOLOGY/PRINCIPAL FINDINGS: We obtained serum samples preoperatively from women with suspected ovarian cancer enrolled through a prospective, population-based rapid ascertainment system. Samples were analyzed from all women in whom a diagnosis of epithelial ovarian cancer (EOC was confirmed and from benign disease cases randomly selected from the remaining (non-EOC samples. We measured biologically relevant phospholipids using liquid chromatography/electrospray ionization mass spectrometry. We applied a powerful statistical and machine learning approach, Hybrid huberized support vector machine (HH-SVM to prioritize phospholipids to enter the biomarker models, and used cross-validation to obtain conservative estimates of classification error rates. RESULTS: The HH-SVM model using the measurements of specific combinations of phospholipids supplements clinical CA125 measurement and improves diagnostic accuracy. Specifically, the measurement of phospholipids improved sensitivity (identification of cases with preoperative CA125 levels below 35 among two types of cases in which CA125 performance is historically poor - early stage cases and those of mucinous histology. Measurement of phospholipids improved the identification of early stage cases from 65% (based on CA125 to 82%, and mucinous cases from 44% to 88%. CONCLUSIONS/SIGNIFICANCE: Levels of specific serum phospholipids differ between women with ovarian cancer and those with benign conditions. If validated by independent studies in the future, these biomarkers may serve as an adjunct at

  5. Transient expression assays in grapevine: a step towards genetic improvement.

    Science.gov (United States)

    Jelly, Noémie S; Valat, Laure; Walter, Bernard; Maillot, Pascale

    2014-12-01

    In the past few years, the usefulness of transient expression assays has continuously increased for the characterization of unknown gene function and metabolic pathways. In grapevine (Vitis vinifera L.), one of the most economically important fruit crops in the world, recent systematic sequencing projects produced many gene data sets that require detailed analysis. Due to their rapid nature, transient expression assays are well suited for large-scale genetic studies. Although genes and metabolic pathways of any species can be analysed by transient expression in model plants, a need for homologous systems has emerged to avoid the misinterpretation of results due to a foreign genetic background. Over the last 10 years, various protocols have thus been developed to apply this powerful technology to grapevine. Using cell suspension cultures, somatic embryos, leaves or whole plantlets, transient expression assays enabled the study of the function, regulation and subcellular localization of genes involved in specific metabolic pathways such as the biosynthesis of phenylpropanoids. Disease resistance genes that could be used for marker-assisted selection in conventional breeding or for stable transformation of elite cultivars have also been characterized. Additionally, transient expression assays have proved useful for shaping new tools for grapevine genetic improvement: synthetic promoters, silencing constructs, minimal linear cassettes or viral vectors. This review provides an update on the different tools (DNA constructs, reporter genes, vectors) and methods (Agrobacterium-mediated and direct gene transfer methods) available for transient gene expression in grapevine. The most representative results published thus far are then described. © 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  6. Forecasting space weather: Can new econometric methods improve accuracy?

    Science.gov (United States)

    Reikard, Gordon

    2011-06-01

    Space weather forecasts are currently used in areas ranging from navigation and communication to electric power system operations. The relevant forecast horizons can range from as little as 24 h to several days. This paper analyzes the predictability of two major space weather measures using new time series methods, many of them derived from econometrics. The data sets are the A p geomagnetic index and the solar radio flux at 10.7 cm. The methods tested include nonlinear regressions, neural networks, frequency domain algorithms, GARCH models (which utilize the residual variance), state transition models, and models that combine elements of several techniques. While combined models are complex, they can be programmed using modern statistical software. The data frequency is daily, and forecasting experiments are run over horizons ranging from 1 to 7 days. Two major conclusions stand out. First, the frequency domain method forecasts the A p index more accurately than any time domain model, including both regressions and neural networks. This finding is very robust, and holds for all forecast horizons. Combining the frequency domain method with other techniques yields a further small improvement in accuracy. Second, the neural network forecasts the solar flux more accurately than any other method, although at short horizons (2 days or less) the regression and net yield similar results. The neural net does best when it includes measures of the long-term component in the data.

  7. Stratified computed tomography findings improve diagnostic accuracy for appendicitis

    Science.gov (United States)

    Park, Geon; Lee, Sang Chul; Choi, Byung-Jo; Kim, Say-June

    2014-01-01

    AIM: To improve the diagnostic accuracy in patients with symptoms and signs of appendicitis, but without confirmative computed tomography (CT) findings. METHODS: We retrospectively reviewed the database of 224 patients who had been operated on for the suspicion of appendicitis, but whose CT findings were negative or equivocal for appendicitis. The patient population was divided into two groups: a pathologically proven appendicitis group (n = 177) and a non-appendicitis group (n = 47). The CT images of these patients were re-evaluated according to the characteristic CT features as described in the literature. The re-evaluations and baseline characteristics of the two groups were compared. RESULTS: The two groups showed significant differences with respect to appendiceal diameter, and the presence of periappendiceal fat stranding and intraluminal air in the appendix. A larger proportion of patients in the appendicitis group showed distended appendices larger than 6.0 mm (66.3% vs 37.0%; P appendicitis group. Furthermore, the presence of two or more of these factors increased the odds ratio to 6.8 times higher than baseline (95%CI: 3.013-15.454; P appendicitis with equivocal CT findings. PMID:25320531

  8. THE ACCURACY AND BIAS EVALUATION OF THE USA UNEMPLOYMENT RATE FORECASTS. METHODS TO IMPROVE THE FORECASTS ACCURACY

    Directory of Open Access Journals (Sweden)

    MIHAELA BRATU (SIMIONESCU

    2012-12-01

    Full Text Available In this study some alternative forecasts for the unemployment rate of USA made by four institutions (International Monetary Fund (IMF, Organization for Economic Co-operation and Development (OECD, Congressional Budget Office (CBO and Blue Chips (BC are evaluated regarding the accuracy and the biasness. The most accurate predictions on the forecasting horizon 201-2011 were provided by IMF, followed by OECD, CBO and BC.. These results were gotten using U1 Theil’s statistic and a new method that has not been used before in literature in this context. The multi-criteria ranking was applied to make a hierarchy of the institutions regarding the accuracy and five important accuracy measures were taken into account at the same time: mean errors, mean squared error, root mean squared error, U1 and U2 statistics of Theil. The IMF, OECD and CBO predictions are unbiased. The combined forecasts of institutions’ predictions are a suitable strategy to improve the forecasts accuracy of IMF and OECD forecasts when all combination schemes are used, but INV one is the best. The filtered and smoothed original predictions based on Hodrick-Prescott filter, respectively Holt-Winters technique are a good strategy of improving only the BC expectations. The proposed strategies to improve the accuracy do not solve the problem of biasness. The assessment and improvement of forecasts accuracy have an important contribution in growing the quality of decisional process.

  9. An improved in vitro micronucleus assay to biological dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Ocampo, Ivette Z.; Okazaki, Kayo; Vieira, Daniel P., E-mail: dpvieira@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), So Paulo, SP (Brazil)

    2013-07-01

    The biological dosimetry is widely used to estimate the absorbed dose in people occupationally or accidentally exposed to the radiation for a better medical treatment, minimizing the harmful effects. Many techniques and methods have been proposed to detect and quantify the radioinduced lesions in genetic material, among them, the micronucleus (MN) assay. In the present study, we proposed an improved in vitro micronucleus technique that is rapid, sensitive and with minor cell manipulations. Assays were carried out with human tumor cells (MCF-7) seeded (3x10{sup 4} cells) in slides placed into Petri dishes. Adherent cells were maintained with RPMI medium, supplemented with fetal calf serum, 1 % antibiotics, cytochalasin B (2 μg/mL), and incubated at 37 deg C in the presence of 5% CO2 for 72h. Cells were pre-treated for 24h with aminoguanidine, a nitric oxide synthase inhibitor. Nitric oxide is an intracellular free-radical, involved in DNA double-strand break repair mechanisms. After incubation, adherent cells on slides were briefly fixed with paraformaldehyde and stained with acridine orange (100 μg/mL) for analysis through fluorescence microscopy. Dye fluorescence permitted accurate discrimination between nuclei and micronuclei (bright green) and cytoplasm (red), and made possible a faster counting of binucleated cells. Aminoguanidine (2 mM) induced significant increase (p< 0.05) in frequencies of binucleated cells with micronuclei and in the number of micronuclei per binucleated cell. Data showed that proposed modifications permit to understand an early aspect of NO inhibition and suggested an improved protocol to MN assays. (author)

  10. An Investigation to Improve Classifier Accuracy for Myo Collected Data

    Science.gov (United States)

    2017-02-01

    Bad Samples Effect on Classification Accuracy 7 5.1 Naïve Bayes (NB) Classifier Accuracy 7 5.2 Logistic Model Tree (LMT) 10 5.3 K-Nearest Neighbor...gesture, pitch feature, user 06. All samples exhibit reversed movement...20 Fig. A-2 Come gesture, pitch feature, user 14. All samples exhibit reversed movement

  11. Accuracy of pitch matching significantly improved by live voice model.

    Science.gov (United States)

    Granot, Roni Y; Israel-Kolatt, Rona; Gilboa, Avi; Kolatt, Tsafrir

    2013-05-01

    Singing is, undoubtedly, the most fundamental expression of our musical capacity, yet an estimated 10-15% of Western population sings "out-of-tune (OOT)." Previous research in children and adults suggests, albeit inconsistently, that imitating a human voice can improve pitch matching. In the present study, we focus on the potentially beneficial effects of the human voice and especially the live human voice. Eighteen participants varying in their singing abilities were required to imitate in singing a set of nine ascending and descending intervals presented to them in five different randomized blocked conditions: live piano, recorded piano, live voice using optimal voice production, recorded voice using optimal voice production, and recorded voice using artificial forced voice production. Pitch and interval matching in singing were much more accurate when participants repeated sung intervals as compared with intervals played to them on the piano. The advantage of the vocal over the piano stimuli was robust and emerged clearly regardless of whether piano tones were played live and in full view or were presented via recording. Live vocal stimuli elicited higher accuracy than recorded vocal stimuli, especially when the recorded vocal stimuli were produced in a forced vocal production. Remarkably, even those who would be considered OOT singers on the basis of their performance when repeating piano tones were able to pitch match live vocal sounds, with deviations well within the range of what is considered accurate singing (M=46.0, standard deviation=39.2 cents). In fact, those participants who were most OOT gained the most from the live voice model. Results are discussed in light of the dual auditory-motor encoding of pitch analogous to that found in speech. Copyright © 2013 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  12. The trade-off between accuracy and accessibility of syphilis screening assays.

    Directory of Open Access Journals (Sweden)

    Pieter W Smit

    Full Text Available The availability of rapid and sensitive methods to diagnose syphilis facilitates screening of pregnant women, which is one of the most cost-effective health interventions available. We have evaluated two screening methods in Tanzania: an enzyme immunoassay (EIA, and a point-of-care test (POCT. We evaluated the performance of each test against the Treponema pallidum particle agglutination assay (TPPA as the reference method, and the accessibility of testing in a rural district of Tanzania. The POCT was performed in the clinic on whole blood, while the other assays were performed on plasma in the laboratory. Samples were also tested by the rapid plasma Reagin (RPR test. With TPPA as reference assay, the sensitivity and specificity of EIA were 95.3% and 97.8%, and of the POCT were 59.6% and 99.4% respectively. The sensitivity of the POCT and EIA for active syphilis cases (TPPA positive and RPR titer ≥ 1/8 were 82% and 100% respectively. Only 15% of antenatal clinic attenders in this district visited a health facility with a laboratory capable of performing the EIA. Although it is less sensitive than EIA, its greater accessibility, and the fact that treatment can be given on the same day, means that the use of POCT would result in a higher proportion of women with syphilis receiving treatment than with the EIA in this district of Tanzania.

  13. A Novel Navigation Robustness and Accuracy Improvement System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address NASA's need for L1 C/A-based navigation with better anti-spoofing ability and higher accuracy, Broadata Communications, Inc. (BCI) proposes to develop a...

  14. Analytical Tools to Improve Optimization Procedures for Lateral Flow Assays

    Directory of Open Access Journals (Sweden)

    Helen V. Hsieh

    2017-05-01

    Full Text Available Immunochromatographic or lateral flow assays (LFAs are inexpensive, easy to use, point-of-care medical diagnostic tests that are found in arenas ranging from a doctor’s office in Manhattan to a rural medical clinic in low resource settings. The simplicity in the LFA itself belies the complex task of optimization required to make the test sensitive, rapid and easy to use. Currently, the manufacturers develop LFAs by empirical optimization of material components (e.g., analytical membranes, conjugate pads and sample pads, biological reagents (e.g., antibodies, blocking reagents and buffers and the design of delivery geometry. In this paper, we will review conventional optimization and then focus on the latter and outline analytical tools, such as dynamic light scattering and optical biosensors, as well as methods, such as microfluidic flow design and mechanistic models. We are applying these tools to find non-obvious optima of lateral flow assays for improved sensitivity, specificity and manufacturing robustness.

  15. Detection of Mycoplasma bovis with an improved pcr assay.

    Science.gov (United States)

    Tenk, M; Bálint, A; Stipkovits, L; Biró, Judit; Dencso, L

    2006-12-01

    A Mycoplasma bovis species-specific PCR assay has been developed with improvement of a previously described method (Ghadersohi et al., 1997). This test and its semi-nested version (Hayman and Hirst, 2003) did not function at all in our hands. A new reverse primer (Mbr2) was designed using previously published sequence data. For testing specificity, DNA was extracted from the most frequently occurring mycoplasma species and bacteria of bovine origin. The new PCR detected only Mycoplasma bovis. Moreover, no cross-reaction was observed with the genetically closest relative species, M. agalactiae. The target organism could be detected in a dose as low as 150 CFU ml(-1) in broth cultures using ethidium-bromide-stained agarose gels.

  16. Accuracy Improvement in Magnetic Field Modeling for an Axisymmetric Electromagnet

    Science.gov (United States)

    Ilin, Andrew V.; Chang-Diaz, Franklin R.; Gurieva, Yana L.; Il,in, Valery P.

    2000-01-01

    This paper examines the accuracy and calculation speed for the magnetic field computation in an axisymmetric electromagnet. Different numerical techniques, based on an adaptive nonuniform grid, high order finite difference approximations, and semi-analitical calculation of boundary conditions are considered. These techniques are being applied to the modeling of the Variable Specific Impulse Magnetoplasma Rocket. For high-accuracy calculations, a fourth-order scheme offers dramatic advantages over a second order scheme. For complex physical configurations of interest in plasma propulsion, a second-order scheme with nonuniform mesh gives the best results. Also, the relative advantages of various methods are described when the speed of computation is an important consideration.

  17. Does a Structured Data Collection Form Improve The Accuracy of ...

    African Journals Online (AJOL)

    Objectives: To determine the extent to which use of a structured data collection form (SDCF) affected the diagnostic accuracy of AAP. Methodology: A before and after study carried out from October 2011 to March 2012 of patients aged 13 years and older presenting with AAP in the emergency department (ED) of Aga Khan ...

  18. Optimizing Lumber Production through Improved Accuracy of Side ...

    African Journals Online (AJOL)

    maximum yield of useful product from each tree in order to sustain the wood industry. This work looks at the effect of the accuracy of side clearance of band saw teeth on the surface quality of sawn lumber as well as the level of adherence to quality standards when sawing. Triplochiton scleroxylon (Wawa). The results ...

  19. On combining reference data to improve imputation accuracy.

    Directory of Open Access Journals (Sweden)

    Jun Chen

    Full Text Available Genotype imputation is an important tool in human genetics studies, which uses reference sets with known genotypes and prior knowledge on linkage disequilibrium and recombination rates to infer un-typed alleles for human genetic variations at a low cost. The reference sets used by current imputation approaches are based on HapMap data, and/or based on recently available next-generation sequencing (NGS data such as data generated by the 1000 Genomes Project. However, with different coverage and call rates for different NGS data sets, how to integrate NGS data sets of different accuracy as well as previously available reference data as references in imputation is not an easy task and has not been systematically investigated. In this study, we performed a comprehensive assessment of three strategies on using NGS data and previously available reference data in genotype imputation for both simulated data and empirical data, in order to obtain guidelines for optimal reference set construction. Briefly, we considered three strategies: strategy 1 uses one NGS data as a reference; strategy 2 imputes samples by using multiple individual data sets of different accuracy as independent references and then combines the imputed samples with samples based on the high accuracy reference selected when overlapping occurs; and strategy 3 combines multiple available data sets as a single reference after imputing each other. We used three software (MACH, IMPUTE2 and BEAGLE for assessing the performances of these three strategies. Our results show that strategy 2 and strategy 3 have higher imputation accuracy than strategy 1. Particularly, strategy 2 is the best strategy across all the conditions that we have investigated, producing the best accuracy of imputation for rare variant. Our study is helpful in guiding application of imputation methods in next generation association analyses.

  20. Accuracy of an Accelerated, Culture-Based Assay for Detection of Group B Streptococcus

    Directory of Open Access Journals (Sweden)

    Jonathan P. Faro

    2013-01-01

    Full Text Available Objective. To determine the validity of a novel Group B Streptococcus (GBS diagnostic assay for the detection of GBS in antepartum patients. Study Design. Women were screened for GBS colonization at 35 to 37 weeks of gestation. Three vaginal-rectal swabs were collected per patient; two were processed by traditional culture (commercial laboratory versus in-house culture, and the third was processed by an immunoblot-based test, in which a sample is placed over an antibody-coated nitrocellulose membrane, and after a six-hour culture, bound GBS is detected with a secondary antibody. Results. 356 patients were evaluated. Commercial processing revealed a GBS prevalence rate of 85/356 (23.6%. In-house culture provided a prevalence rate of 105/356 (29.5%. When the accelerated GBS test result was compared to the in-house GBS culture, it demonstrated a sensitivity of 97.1% and a specificity of 88.4%. Interobserver reliability for the novel GBS test was 88.2%. Conclusions. The accelerated GBS test provides a high level of validity for the detection of GBS colonization in antepartum patients within 6.5 hours and demonstrates a substantial agreement between observers.

  1. Accuracy of an accelerated, culture-based assay for detection of group B streptococcus.

    Science.gov (United States)

    Faro, Jonathan P; Bishop, Karen; Riddle, Gerald; Ramirez, Mildred M; Katz, Allan R; Turrentine, Mark A; Faro, Sebastian

    2013-01-01

    To determine the validity of a novel Group B Streptococcus (GBS) diagnostic assay for the detection of GBS in antepartum patients. Women were screened for GBS colonization at 35 to 37 weeks of gestation. Three vaginal-rectal swabs were collected per patient; two were processed by traditional culture (commercial laboratory versus in-house culture), and the third was processed by an immunoblot-based test, in which a sample is placed over an antibody-coated nitrocellulose membrane, and after a six-hour culture, bound GBS is detected with a secondary antibody. 356 patients were evaluated. Commercial processing revealed a GBS prevalence rate of 85/356 (23.6%). In-house culture provided a prevalence rate of 105/356 (29.5%). When the accelerated GBS test result was compared to the in-house GBS culture, it demonstrated a sensitivity of 97.1% and a specificity of 88.4%. Interobserver reliability for the novel GBS test was 88.2%. The accelerated GBS test provides a high level of validity for the detection of GBS colonization in antepartum patients within 6.5 hours and demonstrates a substantial agreement between observers.

  2. Assessment of neuropsychiatric symptoms in dementia: Toward improving accuracy

    Directory of Open Access Journals (Sweden)

    Florindo Stella

    Full Text Available ABSTRACT The issue of this article concerned the discussion about tools frequently used tools for assessing neuropsychiatric symptoms of patients with dementia, particularly Alzheimer's disease. The aims were to discuss the main tools for evaluating behavioral disturbances, and particularly the accuracy of the Neuropsychiatric Inventory - Clinician Rating Scale (NPI-C. The clinical approach to and diagnosis of neuropsychiatric syndromes in dementia require suitable accuracy. Advances in the recognition and early accurate diagnosis of psychopathological symptoms help guide appropriate pharmacological and non-pharmacological interventions. In addition, recommended standardized and validated measurements contribute to both scientific research and clinical practice. Emotional distress, caregiver burden, and cognitive impairment often experienced by elderly caregivers, may affect the quality of caregiver reports. The clinician rating approach helps attenuate these misinterpretations. In this scenario, the NPI-C is a promising and versatile tool for assessing neuropsychiatric syndromes in dementia, offering good accuracy and high reliability, mainly based on the diagnostic impression of the clinician. This tool can provide both strategies: a comprehensive assessment of neuropsychiatric symptoms in dementia or the investigation of specific psychopathological syndromes such as agitation, depression, anxiety, apathy, sleep disorders, and aberrant motor disorders, among others.

  3. Preoperative Measurement of Tibial Resection in Total Knee Arthroplasty Improves Accuracy of Postoperative Limb Alignment Restoration

    Directory of Open Access Journals (Sweden)

    Pei-Hui Wu

    2016-01-01

    Conclusions: Using conventional surgical instruments, preoperative measurement of resection thickness of the tibial plateau on radiographs could improve the accuracy of conventional surgical techniques.

  4. Improved uncertainty quantification in nondestructive assay for nonproliferation

    Energy Technology Data Exchange (ETDEWEB)

    Burr, Tom; Croft, Stephen; Jarman, Ken; Nicholson, Andrew; Norman, Claude; Walsh, Stephen

    2016-12-01

    This paper illustrates methods to improve uncertainty quantification (UQ) for non-destructive assay (NDA) measurements used in nuclear nonproliferation. First, it is shown that current bottom-up UQ applied to calibration data is not always adequate, for three main reasons: (1) Because there are errors in both the predictors and the response, calibration involves a ratio of random quantities, and calibration data sets in NDA usually consist of only a modest number of samples (3–10); therefore, asymptotic approximations involving quantities needed for UQ such as means and variances are often not sufficiently accurate; (2) Common practice overlooks that calibration implies a partitioning of total error into random and systematic error, and (3) In many NDA applications, test items exhibit non-negligible departures in physical properties from calibration items, so model-based adjustments are used, but item-specific bias remains in some data. Therefore, improved bottom-up UQ using calibration data should predict the typical magnitude of item-specific bias, and the suggestion is to do so by including sources of item-specific bias in synthetic calibration data that is generated using a combination of modeling and real calibration data. Second, for measurements of the same nuclear material item by both the facility operator and international inspectors, current empirical (top-down) UQ is described for estimating operator and inspector systematic and random error variance components. A Bayesian alternative is introduced that easily accommodates constraints on variance components, and is more robust than current top-down methods to the underlying measurement error distributions.

  5. Evaluation and improvement of LAMP assays for detection of

    African Journals Online (AJOL)

    Abstract: Escherichia coli serogroups O26, O45, O103, O111, O121, O145, and O157 are the causative agents of human diseases, and LAMP assays have been developed for detection of the seven leading STEC serogroups. Objective: To evaluate existing LAMP assays for detection of the seven STEC serogroups, ...

  6. Evaluation and improvement of LAMP assays for detection of ...

    African Journals Online (AJOL)

    Abstract: Escherichia coli serogroups O26, O45, O103, O111, O121, O145, and O157 are the causative agents of human diseas- es, and LAMP assays have been developed for detection of the seven leading STEC serogroups. Objective: To evaluate existing LAMP assays for detection of the seven STEC serogroups, ...

  7. Method for improving accuracy in full evaporation headspace analysis.

    Science.gov (United States)

    Xie, Wei-Qi; Chai, Xin-Sheng

    2017-05-01

    We report a new headspace analytical method in which multiple headspace extraction is incorporated with the full evaporation technique. The pressure uncertainty caused by the solid content change in the samples has a great impact to the measurement accuracy in the conventional full evaporation headspace analysis. The results (using ethanol solution as the model sample) showed that the present technique is effective to minimize such a problem. The proposed full evaporation multiple headspace extraction analysis technique is also automated and practical, and which could greatly broaden the applications of the full-evaporation-based headspace analysis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Improving Volatility Risk Forecasting Accuracy in Industry Sector

    Directory of Open Access Journals (Sweden)

    S. Al Wadi

    2017-01-01

    Full Text Available Recently, the volatility of financial markets has contributed a necessary part to risk management. Volatility risk is characterized as the standard deviation of the constantly compound return per day. This paper presents forecasting of volatility for the Jordanian industry sector after the crisis in 2009. ARIMA and ARIMA-Wavelet Transform (WT have been conducted in order to select the best forecasting model in the content of industry stock market data collected from Amman Stock Exchange (ASE. As a result, the researcher found that ARIMA-WT has more accuracy than ARIMA directly. The results have been introduced using MATLAB 2010a and R programming.

  9. Improving Estimation Accuracy of Aggregate Queries on Data Cubes

    Energy Technology Data Exchange (ETDEWEB)

    Pourabbas, Elaheh; Shoshani, Arie

    2008-08-15

    In this paper, we investigate the problem of estimation of a target database from summary databases derived from a base data cube. We show that such estimates can be derived by choosing a primary database which uses a proxy database to estimate the results. This technique is common in statistics, but an important issue we are addressing is the accuracy of these estimates. Specifically, given multiple primary and multiple proxy databases, that share the same summary measure, the problem is how to select the primary and proxy databases that will generate the most accurate target database estimation possible. We propose an algorithmic approach for determining the steps to select or compute the source databases from multiple summary databases, which makes use of the principles of information entropy. We show that the source databases with the largest number of cells in common provide the more accurate estimates. We prove that this is consistent with maximizing the entropy. We provide some experimental results on the accuracy of the target database estimation in order to verify our results.

  10. COLD-PCR enhanced melting curve analysis improves diagnostic accuracy for KRAS mutations in colorectal carcinoma.

    Science.gov (United States)

    Pritchard, Colin C; Akagi, Laura; Reddy, Poluru L; Joseph, Loren; Tait, Jonathan F

    2010-11-26

    KRAS mutational analysis is the standard of care prior to initiation of treatments targeting the epidermal growth factor receptor (EGFR) in patients with metastatic colorectal cancer. Sensitive methods are required to reliably detect KRAS mutations in tumor samples due to admixture with non-mutated cells. Many laboratories have implemented sensitive tests for KRAS mutations, but the methods often require expensive instrumentation and reagents, parallel reactions, multiple steps, or opening PCR tubes. We developed a highly sensitive, single-reaction, closed-tube strategy to detect all clinically significant mutations in KRAS codons 12 and 13 using the Roche LightCycler® instrument. The assay detects mutations via PCR-melting curve analysis with a Cy5.5-labeled sensor probe that straddles codons 12 and 13. Incorporating a fast COLD-PCR cycling program with a critical denaturation temperature (Tc) of 81°C increased the sensitivity of the assay >10-fold for the majority of KRAS mutations. We compared the COLD-PCR enhanced melting curve method to melting curve analysis without COLD-PCR and to traditional Sanger sequencing. In a cohort of 61 formalin-fixed paraffin-embedded colorectal cancer specimens, 29/61 were classified as mutant and 28/61 as wild type across all methods. Importantly, 4/61 (6%) were re-classified from wild type to mutant by the more sensitive COLD-PCR melting curve method. These 4 samples were confirmed to harbor clinically-significant KRAS mutations by COLD-PCR DNA sequencing. Five independent mixing studies using mutation-discordant pairs of cell lines and patient specimens demonstrated that the COLD-PCR enhanced melting curve assay could consistently detect down to 1% mutant DNA in a wild type background. We have developed and validated an inexpensive, rapid, and highly sensitive clinical assay for KRAS mutations that is the first report of COLD-PCR combined with probe-based melting curve analysis. This assay significantly improved diagnostic

  11. COLD-PCR enhanced melting curve analysis improves diagnostic accuracy for KRAS mutations in colorectal carcinoma

    Directory of Open Access Journals (Sweden)

    Joseph Loren

    2010-11-01

    -based melting curve analysis. This assay significantly improved diagnostic accuracy compared to traditional PCR and direct sequencing.

  12. An Optical Gun Muzzle Sensor To Improve Firing Accuracy

    Science.gov (United States)

    Carbonneau, Raymond; Dubois, Jacques; Harris, Geoffrey

    1986-11-01

    Thermal deformations of gun/tank components can affect the firing accuracy of modern tanks. To alleviate this problem, an optical gun muzzle sensor has been designed to provide corrections to the computer-generated signals responsible for fire control. This paper first summarizes some typical deformations that induce firing inaccuracies, then reviews various optical approaches to sensing the angular position of a gun and finally, discusses the design of an optical instrument recently developed in Canada for this purpose. The technique involves a laser diode transmitter/receiver mounted on a turret roof and a small mirror at the gun muzzle to reflect the laser beam. Thermal distortions induce a beam deflection which is measured by an analogue, two-axis position sensing detector whose output signals are converted into angular corrections and sent to the fire control computer. The optical design and some specific engineering problem's are thoroughly discussed.

  13. Improving axial depth of cut accuracy in micromilling

    DEFF Research Database (Denmark)

    Bissacco, Giuliano; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2004-01-01

    In order to maintain an optimum cutting speed, the reduction of mill diameters requires machine tools with high rotational speed capabilities. A solution to update existing machine tools is the use of high speed attached spindles. Major drawbacks of these attachments are the high thermal expansion...... and their rapid warming and cooling, which prevent the achievement of a steady state. Several other factors, independent on the tool-workpiece interaction, influence the machining accuracy. The cutting parameter most heavily affected is the axial depth of cut which is the most critical when using micro end mills...... provided with conventional milling machines. This paper presents an investigation aimed at the reduction of the error on the axial depth of cut in micromilling operations, in a workshop environment. A method for tool length correction with sub-micrometer resolution by use of an inductive probe...

  14. AN EVALUATION OF USA UNEMPLOYMENT RATE FORECASTS IN TERMS OF ACCURACY AND BIAS. EMPIRICAL METHODS TO IMPROVE THE FORECASTS ACCURACY

    Directory of Open Access Journals (Sweden)

    BRATU (SIMIONESCU MIHAELA

    2013-02-01

    Full Text Available The most accurate forecasts for USA unemployment rate on the horizon 2001-2012, according to U1 Theil’s coefficient and to multi-criteria ranking methods, were provided by International Monetary Fund (IMF, being followed by other institutions as: Organization for Economic Co-operation and Development (OECD, Congressional Budget Office (CBO and Blue Chips (BC. The multi-criteria ranking methods were applied to solve the divergence in assessing the accuracy, differences observed by computing five chosen measures of accuracy: U1 and U2 statistics of Theil, mean error, mean squared error, root mean squared error. Some strategies of improving the accuracy of the predictions provided by the four institutions, which are biased in all cases, excepting BC, were proposed. However, these methods did not generate unbiased forecasts. The predictions made by IMF and OECD for 2001-2012 can be improved by constructing combined forecasts, the INV approach and the scheme proposed by author providing the most accurate expections. The BC forecasts can be improved by smoothing the predictions using Holt-Winters method and Hodrick - Prescott filter.

  15. Improving the accuracy of camber predictions for precast pretensioned concrete beams : [tech transfer summary].

    Science.gov (United States)

    2015-07-01

    Implementing the recommendations of this study is expected to significantly : improve the accuracy of camber measurements and predictions and to : ultimately help reduce construction delays, improve bridge serviceability, : and decrease costs.

  16. A priori estimation of accuracy and of the number of wells to be employed in limiting dilution assays

    Directory of Open Access Journals (Sweden)

    J.G. Chaui-Berlinck

    2000-08-01

    Full Text Available The use of limiting dilution assay (LDA for assessing the frequency of responders in a cell population is a method extensively used by immunologists. A series of studies addressing the statistical method of choice in an LDA have been published. However, none of these studies has addressed the point of how many wells should be employed in a given assay. The objective of this study was to demonstrate how a researcher can predict the number of wells that should be employed in order to obtain results with a given accuracy, and, therefore, to help in choosing a better experimental design to fulfill one's expectations. We present the rationale underlying the expected relative error computation based on simple binomial distributions. A series of simulated in machina experiments were performed to test the validity of the a priori computation of expected errors, thus confirming the predictions. The step-by-step procedure of the relative error estimation is given. We also discuss the constraints under which an LDA must be performed.

  17. Going Vertical To Improve the Accuracy of Atomic Force Microscopy Based Single-Molecule Force Spectroscopy.

    Science.gov (United States)

    Walder, Robert; Van Patten, William J; Adhikari, Ayush; Perkins, Thomas T

    2018-01-23

    Single-molecule force spectroscopy (SMFS) is a powerful technique to characterize the energy landscape of individual proteins, the mechanical properties of nucleic acids, and the strength of receptor-ligand interactions. Atomic force microscopy (AFM)-based SMFS benefits from ongoing progress in improving the precision and stability of cantilevers and the AFM itself. Underappreciated is that the accuracy of such AFM studies remains hindered by inadvertently stretching molecules at an angle while measuring only the vertical component of the force and extension, degrading both measurements. This inaccuracy is particularly problematic in AFM studies using double-stranded DNA and RNA due to their large persistence length (p ≈ 50 nm), often limiting such studies to other SMFS platforms (e.g., custom-built optical and magnetic tweezers). Here, we developed an automated algorithm that aligns the AFM tip above the DNA's attachment point to a coverslip. Importantly, this algorithm was performed at low force (10-20 pN) and relatively fast (15-25 s), preserving the connection between the tip and the target molecule. Our data revealed large uncorrected lateral offsets for 100 and 650 nm DNA molecules [24 ± 18 nm (mean ± standard deviation) and 180 ± 110 nm, respectively]. Correcting this offset yielded a 3-fold improvement in accuracy and precision when characterizing DNA's overstretching transition. We also demonstrated high throughput by acquiring 88 geometrically corrected force-extension curves of a single individual 100 nm DNA molecule in ∼40 min and versatility by aligning polyprotein- and PEG-based protein-ligand assays. Importantly, our software-based algorithm was implemented on a commercial AFM, so it can be broadly adopted. More generally, this work illustrates how to enhance AFM-based SMFS by developing more sophisticated data-acquisition protocols.

  18. A Novel Reporting System to Improve Accuracy in Appendicitis Imaging

    Science.gov (United States)

    Godwin, Benjamin D.; Drake, Frederick T.; Simianu, Vlad V.; Shriki, Jabi E.; Hippe, Daniel S.; Dighe, Manjiri; Bastawrous, Sarah; Cuevas, Carlos; Flum, David; Bhargava, Puneet

    2015-01-01

    OBJECTIVE The purpose of this study was to ascertain if standardized radiologic reporting for appendicitis imaging increases diagnostic accuracy. MATERIALS AND METHODS We developed a standardized appendicitis reporting system that includes objective imaging findings common in appendicitis and a certainty score ranging from 1 (definitely not appendicitis) through 5 (definitely appendicitis). Four radiologists retrospectively reviewed the preoperative CT scans of 96 appendectomy patients using our reporting system. The presence of appendicitis-specific imaging findings and certainty scores were compared with final pathology. These comparisons were summarized using odds ratios (ORs) and the AUC. RESULTS The appendix was visualized on CT in 89 patients, of whom 71 (80%) had pathologically proven appendicitis. Imaging findings associated with appendicitis included appendiceal diameter (odds ratio [OR] = 14 [> 10 vs appendicitis. In this initially indeterminate group, using the standardized reporting system, radiologists assigned higher certainty scores (4 or 5) in 21 of the 28 patients with appendicitis (75%) and lower scores (1 or 2) in five of the seven patients without appendicitis (71%) (AUC = 0.90; p = 0.001). CONCLUSION Standardized reporting and grading of objective imaging findings correlated well with postoperative pathology and may decrease the number of CT findings reported as indeterminate for appendicitis. Prospective evaluation of this reporting system on a cohort of patients with clinically suspected appendicitis is currently under way. PMID:26001230

  19. Singing Video Games May Help Improve Pitch-Matching Accuracy

    Science.gov (United States)

    Paney, Andrew S.

    2015-01-01

    The purpose of this study was to investigate the effect of singing video games on the pitch-matching skills of undergraduate students. Popular games like "Rock Band" and "Karaoke Revolutions" rate players' singing based on the correctness of the frequency of their sung response. Players are motivated to improve their…

  20. Image processing for improved eye-tracking accuracy

    Science.gov (United States)

    Mulligan, J. B.; Watson, A. B. (Principal Investigator)

    1997-01-01

    Video cameras provide a simple, noninvasive method for monitoring a subject's eye movements. An important concept is that of the resolution of the system, which is the smallest eye movement that can be reliably detected. While hardware systems are available that estimate direction of gaze in real-time from a video image of the pupil, such systems must limit image processing to attain real-time performance and are limited to a resolution of about 10 arc minutes. Two ways to improve resolution are discussed. The first is to improve the image processing algorithms that are used to derive an estimate. Off-line analysis of the data can improve resolution by at least one order of magnitude for images of the pupil. A second avenue by which to improve resolution is to increase the optical gain of the imaging setup (i.e., the amount of image motion produced by a given eye rotation). Ophthalmoscopic imaging of retinal blood vessels provides increased optical gain and improved immunity to small head movements but requires a highly sensitive camera. The large number of images involved in a typical experiment imposes great demands on the storage, handling, and processing of data. A major bottleneck had been the real-time digitization and storage of large amounts of video imagery, but recent developments in video compression hardware have made this problem tractable at a reasonable cost. Images of both the retina and the pupil can be analyzed successfully using a basic toolbox of image-processing routines (filtering, correlation, thresholding, etc.), which are, for the most part, well suited to implementation on vectorizing supercomputers.

  1. Improved DORIS accuracy for precise orbit determination and geodesy

    Science.gov (United States)

    Willis, Pascal; Jayles, Christian; Tavernier, Gilles

    2004-01-01

    In 2001 and 2002, 3 more DORIS satellites were launched. Since then, all DORIS results have been significantly improved. For precise orbit determination, 20 cm are now available in real-time with DIODE and 1.5 to 2 cm in post-processing. For geodesy, 1 cm precision can now be achieved regularly every week, making now DORIS an active part of a Global Observing System for Geodesy through the IDS.

  2. Diagnostic accuracy of quantitative real-time PCR assay versus clinical and Gram stain identification of bacterial vaginosis.

    Science.gov (United States)

    Menard, J-P; Mazouni, C; Fenollar, F; Raoult, D; Boubli, L; Bretelle, F

    2010-12-01

    The purpose of this investigation was to determine the diagnostic accuracy of quantitative real-time polymerase chain reaction (PCR) assay in diagnosing bacterial vaginosis versus the standard methods, the Amsel criteria and the Nugent score. The Amsel criteria, the Nugent score, and results from the molecular tool were obtained independently from vaginal samples of 163 pregnant women who reported abnormal vaginal symptoms before 20 weeks gestation. To determine the performance of the molecular tool, we calculated the kappa value, sensitivity, specificity, and positive and negative predictive values. Either or both of the Amsel criteria (≥3 criteria) and the Nugent score (score ≥7) indicated that 25 women (15%) had bacterial vaginosis, and the remaining 138 women did not. DNA levels of Gardnerella vaginalis or Atopobium vaginae exceeded 10(9) copies/mL or 10(8) copies/mL, respectively, in 34 (21%) of the 163 samples. Complete agreement between both reference methods and high concentrations of G. vaginalis and A. vaginae was found in 94.5% of women (154/163 samples, kappa value = 0.81, 95% confidence interval 0.70-0.81). The nine samples with discordant results were categorized as intermediate flora by the Nugent score. The molecular tool predicted bacterial vaginosis with a sensitivity of 100%, a specificity of 93%, a positive predictive value of 73%, and a negative predictive value of 100%. The quantitative real-time PCR assay shows excellent agreement with the results of both reference methods for the diagnosis of bacterial vaginosis.

  3. Improved bioautographic assay on TLC layers for qualitative and quantitative estimation of xanthine oxidase inhibitors and superoxide scavengers.

    Science.gov (United States)

    Kong, Yao; Li, Xiangkun; Zhang, Na; Miao, Yu; Feng, Haiyan; Wu, Tao; Cheng, Zhihong

    2018-02-20

    A new agar-free bioautographic assay for xanthine oxidase (XO) inhibitors and superoxide scavengers on TLC layers was developed and validated. Compared to the first version of TLC bioautographic agar overlay method, our bioautographic assay greatly improved the sensitivity and quantification ability. The limit of detection (LOD) of this assay was 0.017ng for allopurinol. Quantitative estimation of XO inhibitors and superoxide scavengers was achieved by densitometry scanning, expressed as allopurinol equivalents in millimoles on a per sample weight basis. This assay has acceptable accuracy (95.37-99.23%), intra-day and inter-day precisions (RSD, 2.56-6.69%), as well as intra-plate and inter-plate precisions (RSD, 2.93-9.62%). Six pure compounds and three herbal extracts were evaluated for their potential XO inhibitory and superoxide scavenging activity by this bioautographic assay on TLC layers. Four active components were separated, located and identified in Astragalus membranaceus var. mongholicus extract by the bioautographic assay after TLC separation. The developed method is rapid, simple, sensitive and stable for screening and estimation of the potential XO inhibitors and superoxide scavengers. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Qualification of standard membrane-feeding assay with Plasmodium falciparum malaria and potential improvements for future assays.

    Directory of Open Access Journals (Sweden)

    Kazutoyo Miura

    Full Text Available Vaccines that interrupt malaria transmission are of increasing interest and a robust functional assay to measure this activity would promote their development by providing a biologically relevant means of evaluating potential vaccine candidates. Therefore, we aimed to qualify the standard membrane-feeding assay (SMFA. The assay measures the transmission-blocking activity of antibodies by feeding cultured P. falciparum gametocytes to Anopheles mosquitoes in the presence of the test antibodies and measuring subsequent mosquito infection. The International Conference on Harmonisation (ICH Harmonised Tripartite Guideline Q2(R1 details characteristics considered in assay validation. Of these characteristics, we decided to qualify the SMFA for Precision, Linearity, Range and Specificity. The transmission-blocking 4B7 monoclonal antibody was tested over 6 feeding experiments at several concentrations to determine four suitable concentrations that were tested in triplicate in the qualification experiments (3 additional feeds to evaluate Precision, Linearity and Range. For Specificity, 4B7 was tested in the presence of normal mouse IgG. We determined intra- and inter-assay variability of % inhibition of mean oocyst intensity at each concentration of 4B7 (lower concentrations showed higher variability. We also showed that % inhibition was dependent on 4B7 concentration and the activity is specific to 4B7. Since obtaining empirical data is time-consuming, we generated a model using data from all 9 feeds and simulated the effects of different parameters on final readouts to improve the assay procedure and analytical methods for future studies. For example, we estimated the effect of number of mosquitoes dissected on variability of % inhibition, and simulated the relationship between % inhibition in oocyst intensity and % inhibition of prevalence of infected mosquitos at different mean oocysts in the control. SMFA is one of the few biological assays used in

  5. Qualification of standard membrane-feeding assay with Plasmodium falciparum malaria and potential improvements for future assays.

    Science.gov (United States)

    Miura, Kazutoyo; Deng, Bingbing; Tullo, Gregory; Diouf, Ababacar; Moretz, Samuel E; Locke, Emily; Morin, Merribeth; Fay, Michael P; Long, Carole A

    2013-01-01

    Vaccines that interrupt malaria transmission are of increasing interest and a robust functional assay to measure this activity would promote their development by providing a biologically relevant means of evaluating potential vaccine candidates. Therefore, we aimed to qualify the standard membrane-feeding assay (SMFA). The assay measures the transmission-blocking activity of antibodies by feeding cultured P. falciparum gametocytes to Anopheles mosquitoes in the presence of the test antibodies and measuring subsequent mosquito infection. The International Conference on Harmonisation (ICH) Harmonised Tripartite Guideline Q2(R1) details characteristics considered in assay validation. Of these characteristics, we decided to qualify the SMFA for Precision, Linearity, Range and Specificity. The transmission-blocking 4B7 monoclonal antibody was tested over 6 feeding experiments at several concentrations to determine four suitable concentrations that were tested in triplicate in the qualification experiments (3 additional feeds) to evaluate Precision, Linearity and Range. For Specificity, 4B7 was tested in the presence of normal mouse IgG. We determined intra- and inter-assay variability of % inhibition of mean oocyst intensity at each concentration of 4B7 (lower concentrations showed higher variability). We also showed that % inhibition was dependent on 4B7 concentration and the activity is specific to 4B7. Since obtaining empirical data is time-consuming, we generated a model using data from all 9 feeds and simulated the effects of different parameters on final readouts to improve the assay procedure and analytical methods for future studies. For example, we estimated the effect of number of mosquitoes dissected on variability of % inhibition, and simulated the relationship between % inhibition in oocyst intensity and % inhibition of prevalence of infected mosquitos at different mean oocysts in the control. SMFA is one of the few biological assays used in preclinical and

  6. The study of vehicle classification equipment with solutions to improve accuracy in Oklahoma.

    Science.gov (United States)

    2014-12-01

    The accuracy of vehicle counting and classification data is vital for appropriate future highway and road : design, including determining pavement characteristics, eliminating traffic jams, and improving safety. : Organizations relying on vehicle cla...

  7. Improving the accuracy and usability of Iowa falling weight deflectometer data.

    Science.gov (United States)

    2013-05-01

    This study aims to improve the accuracy and usability of Iowa Falling Weight Deflectometer (FWD) data by incorporating significant : enhancements into the fully-automated software system for rapid processing of the FWD data. These enhancements includ...

  8. A modified digital image correlation with enhanced speed and improved accuracy

    Science.gov (United States)

    Li, Bang-Jian; Wang, Quan-Bao; Duan, Deng-Ping

    2017-02-01

    Digital image correlation (DIC) is widely applied in optical measurement field. In this work, the classical DIC algorithm is modified to improve the speed and enhance the measurement accuracy. A Butterworth function is installed on the traditional sum-of-squared differences correlation criterion. And inverse compositional Gauss-Newton is carried out. The computer generated speckle patterns are used to demonstrate the presented algorithm. The results declare the proposed method can improve the speed with enhanced measurement accuracy.

  9. Improving the positional accuracy of the goniometer on the Philips CM series TEM.

    Science.gov (United States)

    Pulokas, J; Green, C; Kisseberth, N; Potter, C S; Carragher, B

    1999-12-30

    We have developed a method to improve the accuracy for absolute relocation of a target specimen using the goniometer on a Philips transmission electron microscope. We have achieved this by characterizing the performance of the Philips compustage, modeling its behavior, and using this model to calculate the goniometer movements required for accurate target relocation. This resulted in a 10-fold improvement in the positioning accuracy of the goniometer. Copyright 1999 Academic Press.

  10. Development of an improved microneutralization assay for respiratory syncytial virus by automated plaque counting using imaging analysis

    Directory of Open Access Journals (Sweden)

    Quiroz Jorge

    2005-11-01

    Full Text Available Abstract Background Respiratory syncytial virus (RSV is the major cause of lower respiratory tract infection in infants and young children. Although several experimental RSV vaccines are under investigation, immuno therapy is the only treatment currently available. In assessing the immunogenicity of various vaccine formulations, a plaque reduction neutralization assay for the evaluation of RSV neutralizing antibody has been widely used. The method produces reliable results, but it is tedious and labor intensive as it relies on manual counting by laboratory personnel. To facilitate evaluation of phase II and phase III vaccine clinical trials, a more rapid, reliable and efficient neutralization assay is needed. Results An improved microneutralization assay for quantifying RSV neutralizing antibodies was developed using an ImmunoSpot® Series I Analyzer (Cellular Technology Ltd., Cleveland, OH for automated plaque counting. The method is an improvement of the established classical microneutralization assay in which immunostained plaques on transparent tissue culture plates are counted manually under a dissecting microscope. Image analyzer technology allows for fully automated counting of plaques distributed throughout an entire well. Adjustments, such as the use of opaque tissue culture plates and the TMB substrate, True Blue™ (KPL, Gaithersburg, MD, were required to adapt the assay for optimal detection of plaques by the image analyzer. The suitability and the accuracy of the method for counting RSV plaques were determined by comparative testing of a reference serum and two control sera by manual and automated counting methods. The results showed that the two methods were highly correlated (R = 0.9580 and the titers generated by them were within two-fold. Conclusion Our results demonstrate that the semi-automated assay is rapid and reliable. It provides results within two fold to the classical plaque microneutralization assay and is readily

  11. Novel methods for improving rapid paper-based protein assays with gold nanoparticle detection

    OpenAIRE

    Lama, Lara

    2017-01-01

    This thesis describes methods for improving sensitivity in rapid singleplex and multiplex microarray assays. The assays utilize the optical characteristics of colloidal gold nanoparticles for the colorimetric detection of proteins. Multiplexed detection in sandwich immunoassays is limited by cross-reactivity between different detection antibodies. The cross-reactivity between antibodies can contribute to increased background noise - decreasing the Limit-of-Detection of the assay - or generate...

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

    Science.gov (United States)

    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.

  13. Improved microbial screning assay for the detection of quinolone residues in poultry and eggs

    NARCIS (Netherlands)

    Pikkemaat, M.G.; Mulder, P.P.J.; Elferink, J.W.A.; Cocq, A.; Nielen, M.W.F.; Egmond, van H.J.

    2007-01-01

    An improved microbiological screening assay is reported for the detection of quinolone residues in poultry muscle and eggs. The method was validated using fortified tissue samples and is the first microbial assay to effectively detect enrofloxacin, difloxacin, danofloxacin, as well as flumequine and

  14. Learning linear spatial-numeric associations improves accuracy of memory for numbers

    Directory of Open Access Journals (Sweden)

    Clarissa Ann Thompson

    2016-01-01

    Full Text Available Memory for numbers improves with age and experience. One potential source of improvement is a logarithmic-to-linear shift in children’s representations of magnitude. To test this, Kindergartners and second graders estimated the location of numbers on number lines and recalled numbers presented in vignettes (Study 1. Accuracy at number-line estimation predicted memory accuracy on a numerical recall task after controlling for the effect of age and ability to approximately order magnitudes (mapper status. To test more directly whether linear numeric magnitude representations caused improvements in memory, half of children were given feedback on their number-line estimates (Study 2. As expected, learning linear representations was again linked to memory for numerical information even after controlling for age and mapper status. These results suggest that linear representations of numerical magnitude may be a causal factor in development of numeric recall accuracy.

  15. Verification and Improving Planimetric Accuracy of Airborne Laser Scanning Data with Using Photogrammetric Data

    Science.gov (United States)

    Bakuła, K.; Dominik, W.; Ostrowski, W.

    2014-03-01

    In this study results of planimetric accuracy of LIDAR data were verified with application of intensity of laser beam reflection and point cloud modelling results. Presented research was the basis for improving the accuracy of the products from the processing of LIDAR data, what is particularly important in issues related to surveying measurements. In the experiment, the true-ortho from the large-format aerial images with known exterior orientation were used to check the planimetric accuracy of LIDAR data in two proposed approaches. First analysis was carried out by comparison the position of the selected points identifiable on true-ortho from aerial images with corresponding points in the raster of reflection intensity reflection. Second method to verify planimetric accuracy used roof ridges from 3D building models automatically created from LIDAR data being intersections of surfaces from point cloud. Both analyses were carried out for 3 fragments of LIDAR strips. Detected systematic planimetric error in size of few centimetres enabled an implementation of appropriate correction for analyzed data locally. The presented problem and proposed solutions provide an opportunity to improve the accuracy of the LiDAR data. Such methods allowed for efficient use by specialists in other fields not directly related to the issues of orientation and accuracy of photogrammetric data during their acquisition and pre-processing

  16. VERIFICATION AND IMPROVING PLANIMETRIC ACCURACY OF AIRBORNE LASER SCANNING DATA WITH USING PHOTOGRAMMETRIC DATA

    Directory of Open Access Journals (Sweden)

    K. Bakuła

    2014-03-01

    Full Text Available In this study results of planimetric accuracy of LIDAR data were verified with application of intensity of laser beam reflection and point cloud modelling results. Presented research was the basis for improving the accuracy of the products from the processing of LIDAR data, what is particularly important in issues related to surveying measurements. In the experiment, the true-ortho from the large-format aerial images with known exterior orientation were used to check the planimetric accuracy of LIDAR data in two proposed approaches. First analysis was carried out by comparison the position of the selected points identifiable on true-ortho from aerial images with corresponding points in the raster of reflection intensity reflection. Second method to verify planimetric accuracy used roof ridges from 3D building models automatically created from LIDAR data being intersections of surfaces from point cloud. Both analyses were carried out for 3 fragments of LIDAR strips. Detected systematic planimetric error in size of few centimetres enabled an implementation of appropriate correction for analyzed data locally. The presented problem and proposed solutions provide an opportunity to improve the accuracy of the LiDAR data. Such methods allowed for efficient use by specialists in other fields not directly related to the issues of orientation and accuracy of photogrammetric data during their acquisition and pre-processing

  17. Training readers to improve their accuracy in grading Crohn's disease activity on MRI

    Energy Technology Data Exchange (ETDEWEB)

    Tielbeek, Jeroen A.W.; Bipat, Shandra; Boellaard, Thierry N.; Nio, C.Y.; Stoker, Jaap [University of Amsterdam, Department of Radiology, Academic Medical Center, Amsterdam (Netherlands)

    2014-05-15

    To prospectively evaluate if training with direct feedback improves grading accuracy of inexperienced readers for Crohn's disease activity on magnetic resonance imaging (MRI). Thirty-one inexperienced readers assessed 25 cases as a baseline set. Subsequently, all readers received training and assessed 100 cases with direct feedback per case, randomly assigned to four sets of 25 cases. The cases in set 4 were identical to the baseline set. Grading accuracy, understaging, overstaging, mean reading times and confidence scores (scale 0-10) were compared between baseline and set 4, and between the four consecutive sets with feedback. Proportions of grading accuracy, understaging and overstaging per set were compared using logistic regression analyses. Mean reading times and confidence scores were compared by t-tests. Grading accuracy increased from 66 % (95 % CI, 56-74 %) at baseline to 75 % (95 % CI, 66-81 %) in set 4 (P = 0.003). Understaging decreased from 15 % (95 % CI, 9-23 %) to 7 % (95 % CI, 3-14 %) (P < 0.001). Overstaging did not change significantly (20 % vs 19 %). Mean reading time decreased from 6 min 37 s to 4 min 35 s (P < 0.001). Mean confidence increased from 6.90 to 7.65 (P < 0.001). During training, overall grading accuracy, understaging, mean reading times and confidence scores improved gradually. Inexperienced readers need training with at least 100 cases to achieve the literature reported grading accuracy of 75 %. (orig.)

  18. A Tool to Improve Accuracy of Parental Measurements of Preschool Child Height

    Directory of Open Access Journals (Sweden)

    Meredith Yorkin

    2015-01-01

    Full Text Available Background. Parent-reported measurement of child height is common in public health research but may be inaccurate, especially for preschoolers. A standardized protocol and tools to improve measurement accuracy are needed. The purpose of this study was to develop and test materials to improve parents’ accuracy when measuring their preschooler’s height. Methods. In Phase A, 24 parents were observed measuring child height using written instructions and an easy-to-read tape measure; after each of 3 testing rounds, instructions were refined based on observed errors and parent versus researcher measurements. In Phase B, a video replaced written instructions and was refined over 4 rounds with 37 parents. Results. The height kit with written instructions, tape measure, plumb line, and explanatory video helped parents accurately measure child height. Compared to written instructions alone, parents rated the video as having significantly greater clarity and likelihood of improving measurements. Although no significant differences in accuracy were found between paper and video instructions, observations indicated written instructions were more difficult for parents with less education to use with fidelity. Conclusions. The kit may improve parent measurement of preschooler height, thereby improving accuracy of body mass index calculations, tracking of obesity prevalence, and obesity prevention and treatment.

  19. A model to improve the accuracy of US Poison Center data collection.

    Science.gov (United States)

    Krenzelok, E P; Reynolds, K M; Dart, R C; Green, J L

    2014-01-01

    Over 2 million human exposure calls are reported annually to United States regional poison information centers. All exposures are documented electronically and submitted to the American Association of Poison Control Center's National Poison Data System. This database represents the largest data source available on the epidemiology of pharmaceutical and non-pharmaceutical poisoning exposures. The accuracy of these data is critical; however, research has demonstrated that inconsistencies and inaccuracies exist. This study outlines the methods and results of a training program that was developed and implemented to enhance the quality of data collection using acetaminophen exposures as a model. Eleven poison centers were assigned randomly to receive either passive or interactive education to improve medical record documentation. A task force provided recommendations on educational and training strategies and the development of a quality-measurement scorecard to serve as a data collection tool to assess poison center data quality. Poison centers were recruited to participate in the study. Clinical researchers scored the documentation of each exposure record for accuracy. Results. Two thousand two hundred cases were reviewed and assessed for accuracy of data collection. After training, the overall mean quality scores were higher for both the passive (95.3%; + 1.6% change) and interactive intervention groups (95.3%; + 0.9% change). Data collection accuracy improved modestly for the overall accuracy score and significantly for the substance identification component. There was little difference in accuracy measures between the different training methods. Despite the diversity of poison centers, data accuracy, specifically substance identification data fields, can be improved by developing a standardized, systematic, targeted, and mandatory training process. This process should be considered for training on other important topics, thus enhancing the value of these data in

  20. Improvement of Accuracy in Damage Localization Using Frequency Slice Wavelet Transform

    Directory of Open Access Journals (Sweden)

    Xinglong Liu

    2012-01-01

    Full Text Available Damage localization is a primary objective of damage identification. This paper presents damage localization in beam structure using impact-induced Lamb wave and Frequency Slice Wavelet Transform (FSWT. FSWT is a new time-frequency analysis method and has the adaptive resolution feature. The time-frequency resolution is a vital factor affecting the accuracy of damage localization. In FSWT there is a unique parameter controlling the time-frequency resolution. To improve the accuracy of damage localization, a generalized criterion is proposed to determine the parameter value for achieving a suitable time-frequency resolution. For damage localization, the group velocity dispersion curve (GVDC of A0 Lamb waves in beam is first accurately estimated using FSWT, and then the arrival times of reflection wave from the crack for some individual frequency components are determined. An average operation on the calculated propagation distance is then performed to further improve the accuracy of damage localization.

  1. Diagnostic Accuracies of the TUNEL, SCD, and Comet Based Sperm DNA Fragmentation Assays for Male Infertility: a Meta-analysis Study.

    Science.gov (United States)

    Cui, Zhao-Lei; Zheng, De-Zhu; Liu, Yao-Hua; Chen, Liang-Yuan; Lin, Dong-Hong; Feng-Hua Lan

    2015-01-01

    Recent studies have provided new insights into the diagnostic value of sperm DNA fragmentation (SDF) for male factor sterility. This study aimed to systematically evaluate the diagnostic accuracy of the SDF test for male infertility. Eligible studies were retrieved by searching electronic databases. The quality of the studies was assessed on the basis of quality assessment for studies of diagnostic accuracy (QUADAS) criteria tool. The bivariate metaanalysis model was employed to summarize the diagnostic indices and plot the summary receiver operator characteristic (SROC) curve by using Meta-disc 1.4 software. Influence analysis, meta-regression, and publication bias assay were all conducted through Stata 12.0 software. Our bivariate random effect meta-analysis yielded an AUC (area under curve) value of 0.9211 with a sensitivity (95% confidence interval) of 0.80 (0.78 - 0.82) and specificity of 0.83 (0.80 - 0.86) for the use of the SDF test in differentiating infertile males from normal fertile controls. Moreover, our subgroup analysis suggested that SDF analysis with a single TUNEL test resulted in an AUC value of 0.9506, with a pooled sensitivity of 0.77 (0.74 - 0.80) and specificity of 0.91 (0.87 - 0.94), while SCD and Comet assays displayed a combined sensitivity of 0.77 (0.67 - 0.81) or 0.91 (0.88 - 0.94), and specificity of 0.84 (0.75 - 0.91) or 0.63 (0.54 - 0.70), accompanied by an AUC value of 0.8408 or 0.9473. The SDF assay confers a relatively high diagnostic accuracy for infertility detection, among which the TUNEL based methodology seems to achieve higher accuracy than the SCD and Comet assays.

  2. Improving the accuracy of genomic prediction in Chinese Holstein cattle by using one-step blending.

    Science.gov (United States)

    Li, Xiujin; Wang, Sheng; Huang, Ju; Li, Leyi; Zhang, Qin; Ding, Xiangdong

    2014-10-14

    The one-step blending approach has been suggested for genomic prediction in dairy cattle. The core of this approach is to incorporate pedigree and phenotypic information of non-genotyped animals. The objective of this study was to investigate the improvement of the accuracy of genomic prediction using the one-step blending method in Chinese Holstein cattle. Three methods, GBLUP (genomic best linear unbiased prediction), original one-step blending with a genomic relationship matrix, and adjusted one-step blending with an adjusted genomic relationship matrix, were compared with respect to the accuracy of genomic prediction for five milk production traits in Chinese Holstein. For the two one-step blending methods, de-regressed proofs of 17 509 non-genotyped cows, including 424 dams and 17 085 half-sisters of the validation cows, were incorporated in the prediction model. The results showed that, averaged over the five milk production traits, the one-step blending increased the accuracy of genomic prediction by about 0.12 compared to GBLUP. No further improvement in accuracies was obtained from the adjusted one-step blending over the original one-step blending in our situation. Improvements in accuracies obtained with both one-step blending methods were almost completely contributed by the non-genotyped dams. Compared with GBLUP, the one-step blending approach can significantly improve the accuracy of genomic prediction for milk production traits in Chinese Holstein cattle. Thus, the one-step blending is a promising approach for practical genomic selection in Chinese Holstein cattle, where the reference population mainly consists of cows.

  3. Improving Accuracy in α-Models of Turbulence through Approximate Deconvolution

    Directory of Open Access Journals (Sweden)

    Argus A. Dunca

    2017-10-01

    Full Text Available In this report, we present several results in the theory of α -models of turbulence with improved accuracy that have been developed in recent years. The α -models considered herein are the Leray- α model, the zeroth Approximate Deconvolution Model (ADM turbulence model, the modified Leray- α and the Navier–Stokes- α model. For all of the models from above, the accuracy is limited to α 2 in smooth flow regions. Better accuracy requires decreasing the filter radius α , which, in turn, requires a smaller mesh width that will lead in the end to a higher computational cost. Instead, one can use approximate deconvolution (without decreasing the mesh size to attain better accuracy. Such deconvolution methods have been considered recently in many studies that show the efficiency of this approach. For smooth flows, periodic boundary conditions and van Cittert deconvolution operator of order N, the expected accuracy is α 2 N + 2 . In a bounded domain, such results are valid only in case special conditions are satisfied. In more general conditions, the author has recently proved that, in the case of the ADM, the expected accuracy of the finite element method with Taylor–Hood elements and Crank–Nicolson time stepping method is Δ t 2 + h 2 + K N α 2 , where the constant K < 1 depends on the ratio α / h , which is assumed constant. In this study, we present the extension of the result to the rest of the models.

  4. New polymorphic tetranucleotide microsatellites improve scoring accuracy in the bottlenose dolphin Tursiops aduncus

    NARCIS (Netherlands)

    Nater, Alexander; Kopps, Anna M.; Kruetzen, Michael

    We isolated and characterized 19 novel tetranucleotide microsatellite markers in the Indo-Pacific bottlenose dolphin (Tursiops aduncus) in order to improve genotyping accuracy in applications like large-scale population-wide paternity and relatedness assessments. One hundred T. aduncus from Shark

  5. Toward accountable land use mapping: Using geocomputation to improve classification accuracy and reveal uncertainty

    NARCIS (Netherlands)

    Beekhuizen, J.; Clarke, K.C.

    2010-01-01

    The classification of satellite imagery into land use/cover maps is a major challenge in the field of remote sensing. This research aimed at improving the classification accuracy while also revealing uncertain areas by employing a geocomputational approach. We computed numerous land use maps by

  6. A Combined Post-Filtering Method to Improve Accuracy of Variational Optical Flow Estimation

    NARCIS (Netherlands)

    Tu, Z.; Veltkamp, R.C.|info:eu-repo/dai/nl/084742984; van der Aa, N.P.|info:eu-repo/dai/nl/298399679; van Gemeren, C.J.|info:eu-repo/dai/nl/372664571

    We present a novel combined post-filtering (CPF) method to improve the accuracy of optical flow estimation. Its attractive advantages are that outliers reduction is attained while discontinuities are well preserved, and occlusions are partially handled. Major contributions are the following: First,

  7. Operational amplifier speed and accuracy improvement analog circuit design with structural methodology

    CERN Document Server

    Ivanov, Vadim V

    2004-01-01

    Operational Amplifier Speed and Accuracy Improvement proposes a new methodology for the design of analog integrated circuits. The usefulness of this methodology is demonstrated through the design of an operational amplifier. This methodology consists of the following iterative steps: description of the circuit functionality at a high level of abstraction using signal flow graphs; equivalent transformations and modifications of the graph to the form where all important parameters are controlled by dedicated feedback loops; and implementation of the structure using a library of elementary cells. Operational Amplifier Speed and Accuracy Improvement shows how to choose structures and design circuits which improve an operational amplifier's important parameters such as speed to power ratio, open loop gain, common-mode voltage rejection ratio, and power supply rejection ratio. The same approach is used to design clamps and limiting circuits which improve the performance of the amplifier outside of its linear operat...

  8. Accuracy improvement of multimodal measurement of speed of sound based on image processing

    Science.gov (United States)

    Nitta, Naotaka; Kaya, Akio; Misawa, Masaki; Hyodo, Koji; Numano, Tomokazu

    2017-07-01

    Since the speed of sound (SOS) reflects tissue characteristics and is expected as an evaluation index of elasticity and water content, the noninvasive measurement of SOS is eagerly anticipated. However, it is difficult to measure the SOS by using an ultrasound device alone. Therefore, we have presented a noninvasive measurement method of SOS using ultrasound (US) and magnetic resonance (MR) images. By this method, we determine the longitudinal SOS based on the thickness measurement using the MR image and the time of flight (TOF) measurement using the US image. The accuracy of SOS measurement is affected by the accuracy of image registration and the accuracy of thickness measurements in the MR and US images. In this study, we address the accuracy improvement in the latter thickness measurement, and present an image-processing-based method for improving the accuracy of thickness measurement. The method was investigated by using in vivo data obtained from a tissue-engineered cartilage implanted in the back of a rat, with an unclear boundary.

  9. Diagnostic accuracy and usefulness of the Genotype MTBDRplus assay in diagnosing multidrug-resistant tuberculosis in Cameroon? a cross-sectional study.

    Science.gov (United States)

    Abanda, Ngu Njei; Djieugoué, Josiane Yvonne; Lim, Eunjung; Pefura-Yone, Eric Walter; Mbacham, Wilfred Fon; Vernet, Guy; Penlap, Veronique Mbeng; Eyangoh, Sara Irene; Taylor, Diane Wallace; Leke, Rose Gana Fomban

    2017-05-31

    Drug-resistant tuberculosis, especially multidrug-resistant tuberculosis (MDR-TB), is a major public health problem. Effective management of MDR-TB relies on accurate and rapid diagnosis. In this study, we assessed the diagnostic accuracy of the Genotype MTBDRplus assay in diagnosing MDR-TB in Cameroon, and then discuss on its utility within the diagnostic algorithm for MDR-TB. In this cross-sectional study, 225 isolates of Mycobacterium tuberculosis cultured from sputum samples collected from new and previously treated pulmonary tuberculosis patients in Cameroon were used to determine the accuracy of the Genotype MTBDRplus assay. We compared the results of the Genotype MTBDRplus assay with those from the automated liquid culture BACTEC MGIT 960 SIRE system for sensitivity, specificity, and degree of agreement. The pattern of mutations associated with resistance to RIF and INH were also analyzed. The Genotype MTBDRplus assay correctly identified Rifampicin (RIF) resistance in 48/49 isolates (sensitivity, 98% [CI, 89%-100%]), Isoniazid (INH) resistance in 55/60 isolates (sensitivity 92% [CI, 82%-96%]), and MDR-TB in 46/49 (sensitivity, 94% [CI, 83%-98%]). The specificity for the detection of RIF-resistant and MDR-TB cases was 100% (CI, 98%-100%), while that of INH resistance was 99% (CI, 97%-100%). The agreement between the two tests for the detection of MDR-TB was very good (Kappa = 0.96 [CI, 0.92-1.00]). Among the 3 missed MDR-TB cases, the Genotype MTBDRplus assay classified two samples as RIF-monoresistant and one as INH monoresistant. The most frequent mutations detected by the Genotype MTBDRplus assay was the rpoB S531 L MUT3 41/49 (84%) in RIF-resistant isolates, and the KatG S315 T1 (MUT1) 35/55 (64%) and inhA C15T (MUT1) 20/55 (36%) mutations in INH-resistant isolates. The Genotype MTBDRplus assay had good accuracy and could be used for the diagnosis of MDR-TB in Cameroon. For routine MDR-TB diagnosis, this assay could be used for Mycobacterium

  10. IMPROVING THE ACCURACY OF INERTIAL-SATELLITE NAVIGATION SYSTEM IN IMMOBILITY MODE

    Directory of Open Access Journals (Sweden)

    K. V. Kozadaev

    2017-01-01

    Full Text Available A method of improving the accuracy of navigation solutions in immobility mode between motion phases for loosely coupled inertial-satellite system with MEMS sensors is proposed. The method is based on invariance of the dynamic system state while stationary. The test results show the decrease of variation in estimation of geographical coordinates and velocities, and the increase of accuracy of determining the pitch and roll angles for dynamic systems, as well as the lack of increase of the course error.

  11. Use of Tikhonov Regularization to Improve the Accuracy of Position Estimates in Inertial Navigation

    Directory of Open Access Journals (Sweden)

    Tuukka Nieminen

    2011-01-01

    Full Text Available Inertial navigation problems are often understood as initial value problems. However, there are many applications where boundary value problems naturally arise. In these situations, it has been shown that the finite element method can be efficiently used to compute accurate position and velocity estimates. We will propose that finite element method complemented with Tikhonov regularization—a basic tool for inverse problems—is a powerful combination for further accuracy improvements. The proposed method provides a straightforward way to exploit prior information of various types and is subject to rigorous optimality results. Use and accuracy of the proposed method are demonstrated with examples.

  12. After Detection: The Improved Accuracy of Lung Cancer Assessment Using Radiologic Computer-aided Diagnosis.

    Science.gov (United States)

    Amir, Guy J; Lehmann, Harold P

    2016-02-01

    The aim of this study was to evaluate the improved accuracy of radiologic assessment of lung cancer afforded by computer-aided diagnosis (CADx). Inclusion/exclusion criteria were formulated, and a systematic inquiry of research databases was conducted. Following title and abstract review, an in-depth review of 149 surviving articles was performed with accepted articles undergoing a Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-based quality review and data abstraction. A total of 14 articles, representing 1868 scans, passed the review. Increases in the receiver operating characteristic (ROC) area under the curve of .8 or higher were seen in all nine studies that reported it, except for one that employed subspecialized radiologists. This systematic review demonstrated improved accuracy of lung cancer assessment using CADx over manual review, in eight high-quality observer-performance studies. The improved accuracy afforded by radiologic lung-CADx suggests the need to explore its use in screening and regular clinical workflow. Copyright © 2015 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  13. An effective approach to improving low-cost GPS positioning accuracy in real-time navigation.

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Md. Rashedul Islam

    2014-01-01

    Full Text Available 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.

  15. Improvement of a real-time RT-PCR assay for the detection of enterovirus RNA

    Directory of Open Access Journals (Sweden)

    Bruynseels Peggy

    2009-07-01

    Full Text Available Abstract We describe an improvement of an earlier reported real-time RT-PCR assay for the detection of enterovirus RNA, based on the 5' exonuclease digestion of a dual-labeled fluorogenic probe by Taq DNA polymerase. A different extraction method, real-time RT-PCR instrument and primer set were evaluated. Our data show that the optimized assay yields a higher sensitivity and reproducibility and resulted in a significant reduced hands-on time per sample.

  16. Convergence, divergence, and reconvergence in a feedforward network improves neural speed and accuracy

    Science.gov (United States)

    Jeanne, James M.; Wilson, Rachel I.

    2015-01-01

    Summary One of the proposed canonical circuit motifs employed by the brain is a feedforward network where parallel signals converge, diverge, and reconverge. Here we investigate a network with this architecture in the Drosophila olfactory system. We focus on a glomerulus whose receptor neurons converge in an all-to-all manner onto six projection neurons that then reconverge onto higher-order neurons. We find that both convergence and reconvergence improve the ability of a decoder to detect a stimulus based on a single neuron’s spike train. The first transformation implements averaging, and it improves peak detection accuracy but not speed; the second transformation implements coincidence detection, and it improves speed but not peak accuracy. In each case, the integration time and threshold of the postsynaptic cell are matched to the statistics of convergent spike trains. PMID:26586183

  17. Evaluation of real-time PCR assays and standard curve optimisation for enhanced accuracy in quantification of Campylobacter environmental water isolates.

    Science.gov (United States)

    Gosselin-Théberge, Maxime; Taboada, Eduardo; Guy, Rebecca A

    2016-10-01

    Campylobacter is a major public health and economic burden in developed and developing countries. This study evaluated published real-time PCR (qPCR) assays for detection of Campylobacter to enable selection of the best assays for quantification of C. spp. and C. jejuni in environmental water samples. A total of 9 assays were compared: three for thermotolerant C. spp. targeting the 16S rRNA and six for C. jejuni targeting different genes. These assays were tested in the wet-lab for specificity and sensitivity against a collection of 60, genetically diverse, Campylobacter isolates from environmental water. All three qPCR assays targeting C. spp. were positive when tested against the 60 isolates, whereas, assays targeting C. jejuni differed among each other in terms of specificity and sensitivity. Three C. jejuni-specific assays that demonstrated good specificity and sensitivity when tested in the wet-lab showed concordant results with in silico-predicted results obtained against a set of 211 C. jejuni and C. coli genome sequences. Two of the assays targeting C. spp. and C. jejuni were selected to compare DNA concentration estimation, using spectrophotometry and digital PCR (dPCR), in order to calibrate standard curves (SC) for greater accuracy of qPCR-based quantification. Average differences of 0.56±0.12 and 0.51±0.11 log fold copies were observed between the spectrophotometry-based SC preparation and the dPCR preparation for C. spp. and C. jejuni, respectively, demonstrating an over-estimation of Campylobacter concentration when spectrophotometry was used to calibrate the DNA SCs. Our work showed differences in quantification of aquatic environmental isolates of Campylobacter between qPCR assays and method-specific bias in SC preparation. This study provided an objective analysis of qPCR assays targeting Campylobacter in the literature and provides a framework for evaluating novel assays. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  18. Accuracy of the Xpert® MTB/RIF assay for the diagnosis of extra-pulmonary tuberculosis in South Korea.

    Science.gov (United States)

    Kim, Y W; Kwak, N; Seong, M-W; Kim, E-C; Yoo, C-G; Kim, Y W; Han, S K; Yim, J-J

    2015-01-01

    The Xpert(®) MTB/RIF assay has been endorsed by the World Health Organization for the detection of pulmonary and extra-pulmonary tuberculosis (EPTB). To determine the accuracy of the Xpert assay in diagnosing EPTB in South Korea, a country with an intermediate TB burden. We retrospectively reviewed the medical records of 1429 patients in whom the Xpert assay using EPTB specimens was requested between 1 January 2011 and 31 October 2013 in a tertiary referral hospital in South Korea. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the diagnosis of EPTB and detection of rifampicin (RMP) resistance were calculated. Using culture as gold standard, the sensitivity, specificity, PPV and NPV of the assay were respectively 67.7%, 98.1%, 60% and 98.6%. Using a composite reference standard, the sensitivity, specificity, PPV and NPV were respectively 49.3%, 100%, 100% and 95.1%. The sensitivity, specificity, PPV and NPV for the detection of RMP resistance among specimens with positive results for Mycobacterium tuberculosis were respectively 80%, 100%, 100% and 97.7%. The Xpert assay showed acceptable sensitivity in certain groups and excellent specificity in diagnosing EPTB and detecting RMP resistance in an intermediate TB burden country.

  19. Improving measuring accuracy of inharmonious signal voltage under the additive noise condition

    Directory of Open Access Journals (Sweden)

    Horbatyi I. V.

    2017-04-01

    Full Text Available The basic known methods of signal voltage measuring were considered. The circuit solutions used in the construction of digital voltmeters were analyzed. Their advantages and defects were analized. Method of direct assessment of alternating current voltage is proposed to improve by using the developed method for measuring root-mean-square value of alternating current voltage and the device for the realization of the method. It is set, that the use of improved method provides an increase of the inharmonious signal voltage measuring accuracy in conditions of additive noise. Circuit solutions that used for making of digital multimeter using the improved method for measuring of alternating current voltage were described.

  20. Has the use of computers in radiation therapy improved the accuracy in radiation dose delivery?

    Science.gov (United States)

    Van Dyk, J.; Battista, J.

    2014-03-01

    Purpose: It is well recognized that computer technology has had a major impact on the practice of radiation oncology. This paper addresses the question as to how these computer advances have specifically impacted the accuracy of radiation dose delivery to the patient. Methods: A review was undertaken of all the key steps in the radiation treatment process ranging from machine calibration to patient treatment verification and irradiation. Using a semi-quantitative scale, each stage in the process was analysed from the point of view of gains in treatment accuracy. Results: Our critical review indicated that computerization related to digital medical imaging (ranging from target volume localization, to treatment planning, to image-guided treatment) has had the most significant impact on the accuracy of radiation treatment. Conversely, the premature adoption of intensity-modulated radiation therapy has actually degraded the accuracy of dose delivery compared to 3-D conformal radiation therapy. While computational power has improved dose calibration accuracy through Monte Carlo simulations of dosimeter response parameters, the overall impact in terms of percent improvement is relatively small compared to the improvements accrued from 3-D/4-D imaging. Conclusions: As a result of computer applications, we are better able to see and track the internal anatomy of the patient before, during and after treatment. This has yielded the most significant enhancement to the knowledge of "in vivo" dose distributions in the patient. Furthermore, a much richer set of 3-D/4-D co-registered dose-image data is thus becoming available for retrospective analysis of radiobiological and clinical responses.

  1. IMPROVE THE ZY-3 HEIGHT ACCURACY USING ICESAT/GLAS LASER ALTIMETER DATA

    Directory of Open Access Journals (Sweden)

    G. Li

    2016-06-01

    Full Text Available ZY-3 is the first civilian high resolution stereo mapping satellite, which has been launched on 9th, Jan, 2012. The aim of ZY-3 satellite is to obtain high resolution stereo images and support the 1:50000 scale national surveying and mapping. Although ZY-3 has very high accuracy for direct geo-locations without GCPs (Ground Control Points, use of some GCPs is still indispensible for high precise stereo mapping. The GLAS (Geo-science Laser Altimetry System loaded on the ICESat (Ice Cloud and land Elevation Satellite, which is the first laser altimetry satellite for earth observation. GLAS has played an important role in the monitoring of polar ice sheets, the measuring of land topography and vegetation canopy heights after launched in 2003. Although GLAS has ended in 2009, the derived elevation dataset still can be used after selection by some criteria. In this paper, the ICESat/GLAS laser altimeter data is used as height reference data to improve the ZY-3 height accuracy. A selection method is proposed to obtain high precision GLAS elevation data. Two strategies to improve the ZY-3 height accuracy are introduced. One is the conventional bundle adjustment based on RFM and bias-compensated model, in which the GLAS footprint data is viewed as height control. The second is to correct the DSM (Digital Surface Model straightly by simple block adjustment, and the DSM is derived from the ZY-3 stereo imaging after freedom adjustment and dense image matching. The experimental result demonstrates that the height accuracy of ZY-3 without other GCPs can be improved to 3.0 meter after adding GLAS elevation data. What’s more, the comparison of the accuracy and efficiency between the two strategies is implemented for application.

  2. Improving substructure identification accuracy of shear structures using virtual control system

    Science.gov (United States)

    Zhang, Dongyu; Yang, Yang; Wang, Tingqiang; Li, Hui

    2018-02-01

    Substructure identification is a powerful tool to identify the parameters of a complex structure. Previously, the authors developed an inductive substructure identification method for shear structures. The identification error analysis showed that the identification accuracy of this method is significantly influenced by the magnitudes of two key structural responses near a certain frequency; if these responses are unfavorable, the method cannot provide accurate estimation results. In this paper, a novel method is proposed to improve the substructure identification accuracy by introducing a virtual control system (VCS) into the structure. A virtual control system is a self-balanced system, which consists of some control devices and a set of self-balanced forces. The self-balanced forces counterbalance the forces that the control devices apply on the structure. The control devices are combined with the structure to form a controlled structure used to replace the original structure in the substructure identification; and the self-balance forces are treated as known external excitations to the controlled structure. By optimally tuning the VCS’s parameters, the dynamic characteristics of the controlled structure can be changed such that the original structural responses become more favorable for the substructure identification and, thus, the identification accuracy is improved. A numerical example of 6-story shear structure is utilized to verify the effectiveness of the VCS based controlled substructure identification method. Finally, shake table tests are conducted on a 3-story structural model to verify the efficacy of the VCS to enhance the identification accuracy of the structural parameters.

  3. Existing methods for improving the accuracy of digital-to-analog converters

    Science.gov (United States)

    Eielsen, Arnfinn A.; Fleming, Andrew J.

    2017-09-01

    The performance of digital-to-analog converters is principally limited by errors in the output voltage levels. Such errors are known as element mismatch and are quantified by the integral non-linearity. Element mismatch limits the achievable accuracy and resolution in high-precision applications as it causes gain and offset errors, as well as harmonic distortion. In this article, five existing methods for mitigating the effects of element mismatch are compared: physical level calibration, dynamic element matching, noise-shaping with digital calibration, large periodic high-frequency dithering, and large stochastic high-pass dithering. These methods are suitable for improving accuracy when using digital-to-analog converters that use multiple discrete output levels to reconstruct time-varying signals. The methods improve linearity and therefore reduce harmonic distortion and can be retrofitted to existing systems with minor hardware variations. The performance of each method is compared theoretically and confirmed by simulations and experiments. Experimental results demonstrate that three of the five methods provide significant improvements in the resolution and accuracy when applied to a general-purpose digital-to-analog converter. As such, these methods can directly improve performance in a wide range of applications including nanopositioning, metrology, and optics.

  4. An improved haemolytic plaque assay for the detection of cells secreting antibody to bacterial antigens

    DEFF Research Database (Denmark)

    Barington, T; Heilmann, C

    1992-01-01

    Recent advances in the development of conjugate polysaccharide vaccines for human use have stimulated interest in the use of assays detecting antibody-secreting cells (AbSC) with specificity for bacterial antigens. Here we present improved haemolytic plaque-forming cell (PFC) assays detecting Ab......SC with specificity for tetanus and diphtheria toxoid as well as for Haemophilus influenzae type b and pneumococcal capsular polysaccharides. These assays were found to be less time consuming, more economical and yielded 1.9-3.4-fold higher plaque numbers than traditional Jerne-type PFC assays. In the case of anti......-polysaccharide antibodies aggregation of secreted monomeric antibody (IgG) is critical for plaque formation and increases the avidity of binding to target cells....

  5. Improving the accuracy and efficiency of respiratory rate measurements in children using mobile devices.

    Directory of Open Access Journals (Sweden)

    Walter Karlen

    Full Text Available The recommended method for measuring respiratory rate (RR is counting breaths for 60 s using a timer. This method is not efficient in a busy clinical setting. There is an urgent need for a robust, low-cost method that can help front-line health care workers to measure RR quickly and accurately. Our aim was to develop a more efficient RR assessment method. RR was estimated by measuring the median time interval between breaths obtained from tapping on the touch screen of a mobile device. The estimation was continuously validated by measuring consistency (% deviation from the median of each interval. Data from 30 subjects estimating RR from 10 standard videos with a mobile phone application were collected. A sensitivity analysis and an optimization experiment were performed to verify that a RR could be obtained in less than 60 s; that the accuracy improves when more taps are included into the calculation; and that accuracy improves when inconsistent taps are excluded. The sensitivity analysis showed that excluding inconsistent tapping and increasing the number of tap intervals improved the RR estimation. Efficiency (time to complete measurement was significantly improved compared to traditional methods that require counting for 60 s. There was a trade-off between accuracy and efficiency. The most balanced optimization result provided a mean efficiency of 9.9 s and a normalized root mean square error of 5.6%, corresponding to 2.2 breaths/min at a respiratory rate of 40 breaths/min. The obtained 6-fold increase in mean efficiency combined with a clinically acceptable error makes this approach a viable solution for further clinical testing. The sensitivity analysis illustrating the trade-off between accuracy and efficiency will be a useful tool to define a target product profile for any novel RR estimation device.

  6. Improving the accuracy of protein secondary structure prediction using structural alignment

    Directory of Open Access Journals (Sweden)

    Gallin Warren J

    2006-06-01

    Full Text Available Abstract Background The accuracy of protein secondary structure prediction has steadily improved over the past 30 years. Now many secondary structure prediction methods routinely achieve an accuracy (Q3 of about 75%. We believe this accuracy could be further improved by including structure (as opposed to sequence database comparisons as part of the prediction process. Indeed, given the large size of the Protein Data Bank (>35,000 sequences, the probability of a newly identified sequence having a structural homologue is actually quite high. Results We have developed a method that performs structure-based sequence alignments as part of the secondary structure prediction process. By mapping the structure of a known homologue (sequence ID >25% onto the query protein's sequence, it is possible to predict at least a portion of that query protein's secondary structure. By integrating this structural alignment approach with conventional (sequence-based secondary structure methods and then combining it with a "jury-of-experts" system to generate a consensus result, it is possible to attain very high prediction accuracy. Using a sequence-unique test set of 1644 proteins from EVA, this new method achieves an average Q3 score of 81.3%. Extensive testing indicates this is approximately 4–5% better than any other method currently available. Assessments using non sequence-unique test sets (typical of those used in proteome annotation or structural genomics indicate that this new method can achieve a Q3 score approaching 88%. Conclusion By using both sequence and structure databases and by exploiting the latest techniques in machine learning it is possible to routinely predict protein secondary structure with an accuracy well above 80%. A program and web server, called PROTEUS, that performs these secondary structure predictions is accessible at http://wishart.biology.ualberta.ca/proteus. For high throughput or batch sequence analyses, the PROTEUS programs

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

    Science.gov (United States)

    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

  8. Improved spatial accuracy of functional maps in the rat olfactory bulb using supervised machine learning approach.

    Science.gov (United States)

    Murphy, Matthew C; Poplawsky, Alexander J; Vazquez, Alberto L; Chan, Kevin C; Kim, Seong-Gi; Fukuda, Mitsuhiro

    2016-08-15

    Functional MRI (fMRI) is a popular and important tool for noninvasive mapping of neural activity. As fMRI measures the hemodynamic response, the resulting activation maps do not perfectly reflect the underlying neural activity. The purpose of this work was to design a data-driven model to improve the spatial accuracy of fMRI maps in the rat olfactory bulb. This system is an ideal choice for this investigation since the bulb circuit is well characterized, allowing for an accurate definition of activity patterns in order to train the model. We generated models for both cerebral blood volume weighted (CBVw) and blood oxygen level dependent (BOLD) fMRI data. The results indicate that the spatial accuracy of the activation maps is either significantly improved or at worst not significantly different when using the learned models compared to a conventional general linear model approach, particularly for BOLD images and activity patterns involving deep layers of the bulb. Furthermore, the activation maps computed by CBVw and BOLD data show increased agreement when using the learned models, lending more confidence to their accuracy. The models presented here could have an immediate impact on studies of the olfactory bulb, but perhaps more importantly, demonstrate the potential for similar flexible, data-driven models to improve the quality of activation maps calculated using fMRI data. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Accuracy Improvement Capability of Advanced Projectile Based on Course Correction Fuze Concept

    Directory of Open Access Journals (Sweden)

    Ahmed Elsaadany

    2014-01-01

    Full Text Available Improvement in terminal accuracy is an important objective for future artillery projectiles. Generally it is often associated with range extension. Various concepts and modifications are proposed to correct the range and drift of artillery projectile like course correction fuze. The course correction fuze concepts could provide an attractive and cost-effective solution for munitions accuracy improvement. In this paper, the trajectory correction has been obtained using two kinds of course correction modules, one is devoted to range correction (drag ring brake and the second is devoted to drift correction (canard based-correction fuze. The course correction modules have been characterized by aerodynamic computations and flight dynamic investigations in order to analyze the effects on deflection of the projectile aerodynamic parameters. The simulation results show that the impact accuracy of a conventional projectile using these course correction modules can be improved. The drag ring brake is found to be highly capable for range correction. The deploying of the drag brake in early stage of trajectory results in large range correction. The correction occasion time can be predefined depending on required correction of range. On the other hand, the canard based-correction fuze is found to have a higher effect on the projectile drift by modifying its roll rate. In addition, the canard extension induces a high-frequency incidence angle as canards reciprocate at the roll motion.

  10. Accuracy improvement capability of advanced projectile based on course correction fuze concept.

    Science.gov (United States)

    Elsaadany, Ahmed; Wen-jun, Yi

    2014-01-01

    Improvement in terminal accuracy is an important objective for future artillery projectiles. Generally it is often associated with range extension. Various concepts and modifications are proposed to correct the range and drift of artillery projectile like course correction fuze. The course correction fuze concepts could provide an attractive and cost-effective solution for munitions accuracy improvement. In this paper, the trajectory correction has been obtained using two kinds of course correction modules, one is devoted to range correction (drag ring brake) and the second is devoted to drift correction (canard based-correction fuze). The course correction modules have been characterized by aerodynamic computations and flight dynamic investigations in order to analyze the effects on deflection of the projectile aerodynamic parameters. The simulation results show that the impact accuracy of a conventional projectile using these course correction modules can be improved. The drag ring brake is found to be highly capable for range correction. The deploying of the drag brake in early stage of trajectory results in large range correction. The correction occasion time can be predefined depending on required correction of range. On the other hand, the canard based-correction fuze is found to have a higher effect on the projectile drift by modifying its roll rate. In addition, the canard extension induces a high-frequency incidence angle as canards reciprocate at the roll motion.

  11. Contrast-enhanced spectral mammography improves diagnostic accuracy in the symptomatic setting.

    Science.gov (United States)

    Tennant, S L; James, J J; Cornford, E J; Chen, Y; Burrell, H C; Hamilton, L J; Girio-Fragkoulakis, C

    2016-11-01

    To assess the diagnostic accuracy of contrast-enhanced spectral mammography (CESM), and gauge its "added value" in the symptomatic setting. A retrospective multi-reader review of 100 consecutive CESM examinations was performed. Anonymised low-energy (LE) images were reviewed and given a score for malignancy. At least 3 weeks later, the entire examination (LE and recombined images) was reviewed. Histopathology data were obtained for all cases. Differences in performance were assessed using receiver operator characteristic (ROC) analysis. Sensitivity, specificity, and lesion size (versus MRI or histopathology) differences were calculated. Seventy-three percent of cases were malignant at final histology, 27% were benign following standard triple assessment. ROC analysis showed improved overall performance of CESM over LE alone, with area under the curve of 0.93 versus 0.83 (p<0.025). CESM showed increased sensitivity (95% versus 84%, p<0.025) and specificity (81% versus 63%, p<0.025) compared to LE alone, with all five readers showing improved accuracy. Tumour size estimation at CESM was significantly more accurate than LE alone, the latter tending to undersize lesions. In 75% of cases, CESM was deemed a useful or significant aid to diagnosis. CESM provides immediately available, clinically useful information in the symptomatic clinic in patients with suspicious palpable abnormalities. Radiologist sensitivity, specificity, and size accuracy for breast cancer detection and staging are all improved using CESM as the primary mammographic investigation. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  12. The use of modified single pencil beam dose kernels to improve IMRT dose calculation accuracy.

    Science.gov (United States)

    Bergman, Alanah M; Otto, Karl; Duzenli, Cheryl

    2004-12-01

    Intensity modulated radiation therapy (IMRT) is used to deliver highly conformal radiation doses to tumors while sparing nearby sensitive tissues. Discrepancies between calculated and measured dose distributions have been reported for regions of high dose gradients corresponding to complex radiation fluence patterns. For the single pencil beam convolution dose calculation algorithm, the ability to resolve areas of high dose structure is partly related to the shape of the pencil beam dose kernel (similar to how a photon detector's point spread function relates to imaging resolution). Improvements in dose calculation accuracy have been reported when the treatment planning system (TPS) is recommissioned using high-resolution measurement data as input. This study proposes to improve the dose calculation accuracy for IMRT planning by modifying clinical dose kernel shapes already present in the TPS, thus avoiding the need to reacquire higher resolution commissioning data. The in-house optimization program minimizes a cost-function based on a two-dimensional composite dose subtraction/distance-to-agreement (gamma) analysis. The final modified kernel shapes are reintroduced into the treatment planning system and improvements to the dose calcula tion accuracy for complex IMRT dose distributions evaluated. The central kernel value (radius =0 cm) has the largest effect on the dose calculation resolution and is the focus of this study.

  13. Improving decision speed, accuracy and group cohesion through early information gathering in house-hunting ants.

    Directory of Open Access Journals (Sweden)

    Nathalie Stroeymeyt

    Full Text Available BACKGROUND: Successful collective decision-making depends on groups of animals being able to make accurate choices while maintaining group cohesion. However, increasing accuracy and/or cohesion usually decreases decision speed and vice-versa. Such trade-offs are widespread in animal decision-making and result in various decision-making strategies that emphasize either speed or accuracy, depending on the context. Speed-accuracy trade-offs have been the object of many theoretical investigations, but these studies did not consider the possible effects of previous experience and/or knowledge of individuals on such trade-offs. In this study, we investigated how previous knowledge of their environment may affect emigration speed, nest choice and colony cohesion in emigrations of the house-hunting ant Temnothorax albipennis, a collective decision-making process subject to a classical speed-accuracy trade-off. METHODOLOGY/PRINCIPAL FINDINGS: Colonies allowed to explore a high quality nest site for one week before they were forced to emigrate found that nest and accepted it faster than emigrating naïve colonies. This resulted in increased speed in single choice emigrations and higher colony cohesion in binary choice emigrations. Additionally, colonies allowed to explore both high and low quality nest sites for one week prior to emigration remained more cohesive, made more accurate decisions and emigrated faster than emigrating naïve colonies. CONCLUSIONS/SIGNIFICANCE: These results show that colonies gather and store information about available nest sites while their nest is still intact, and later retrieve and use this information when they need to emigrate. This improves colony performance. Early gathering of information for later use is therefore an effective strategy allowing T. albipennis colonies to improve simultaneously all aspects of the decision-making process--i.e. speed, accuracy and cohesion--and partly circumvent the speed-accuracy trade

  14. Anticipating, measuring, and minimizing MEMS mirror scan error to improve laser scanning microscopy's speed and accuracy.

    Science.gov (United States)

    Giannini, John P; York, Andrew G; Shroff, Hari

    2017-01-01

    We describe a method to speed up microelectromechanical system (MEMS) mirror scanning by > 20x, while also improving scan accuracy. We use Landweber deconvolution to determine an input voltage which would produce a desired output, based on the measured MEMS impulse response. Since the MEMS is weakly nonlinear, the observed behavior deviates from expectations, and we iteratively improve our input to minimize this deviation. This allows customizable MEMS angle vs. time with <1% deviation from the desired scan pattern. We demonstrate our technique by optimizing a point scanning microscope's raster patterns to image mammal submandibular gland and pollen at ~10 frames/s.

  15. New technology in dietary assessment: a review of digital methods in improving food record accuracy.

    Science.gov (United States)

    Stumbo, Phyllis J

    2013-02-01

    Methods for conducting dietary assessment in the United States date back to the early twentieth century. Methods of assessment encompassed dietary records, written and spoken dietary recalls, FFQ using pencil and paper and more recently computer and internet applications. Emerging innovations involve camera and mobile telephone technology to capture food and meal images. This paper describes six projects sponsored by the United States National Institutes of Health that use digital methods to improve food records and two mobile phone applications using crowdsourcing. The techniques under development show promise for improving accuracy of food records.

  16. Implementation of the World Health Organization checklist and debriefing improves accuracy of surgical wound class documentation.

    Science.gov (United States)

    Wyrick, Deidre L; Smith, Samuel D; Dassinger, Melvin S

    2015-12-01

    Surgical wound classification (SWC) is a component of surgical site infection risk stratification. Studies have demonstrated that SWC is often incorrectly documented. This study examines the accuracy of SWC after implementation of a multifaceted plan targeted at accurate documentation. A reviewer examined operative notes of 8 pediatric operations and determined SWC for each case. This SWC was compared with nurse-documented SWC. Percent agreement pre- and postintervention was compared. Analysis was performed using chi-square and a P value less than .05 was significant. Preintervention concordance was 58% (112/191) and postintervention was 83% (163/199, P = .001). Appendectomy accuracy was 28% and increased to 80% (P = .0005). Fundoplication accuracy increased from 44% to 84% (P = .016) and gastrostomy tube from 56% to 100% (P = .0002). The most accurate operation preintervention was pyloromyotomy and postintervention was gastrostomy tube and inguinal hernia. The least accurate pre- and postintervention was cholecystectomy. Implementation of a multifaceted approach improved accuracy of documented SWC. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Accuracy improvement techniques in Precise Point Positioning method using multiple GNSS constellations

    Science.gov (United States)

    Vasileios Psychas, Dimitrios; Delikaraoglou, Demitris

    2016-04-01

    The future Global Navigation Satellite Systems (GNSS), including modernized GPS, GLONASS, Galileo and BeiDou, offer three or more signal carriers for civilian use and much more redundant observables. The additional frequencies can significantly improve the capabilities of the traditional geodetic techniques based on GPS signals at two frequencies, especially with regard to the availability, accuracy, interoperability and integrity of high-precision GNSS applications. Furthermore, highly redundant measurements can allow for robust simultaneous estimation of static or mobile user states including more parameters such as real-time tropospheric biases and more reliable ambiguity resolution estimates. This paper presents an investigation and analysis of accuracy improvement techniques in the Precise Point Positioning (PPP) method using signals from the fully operational (GPS and GLONASS), as well as the emerging (Galileo and BeiDou) GNSS systems. The main aim was to determine the improvement in both the positioning accuracy achieved and the time convergence it takes to achieve geodetic-level (10 cm or less) accuracy. To this end, freely available observation data from the recent Multi-GNSS Experiment (MGEX) of the International GNSS Service, as well as the open source program RTKLIB were used. Following a brief background of the PPP technique and the scope of MGEX, the paper outlines the various observational scenarios that were used in order to test various data processing aspects of PPP solutions with multi-frequency, multi-constellation GNSS systems. Results from the processing of multi-GNSS observation data from selected permanent MGEX stations are presented and useful conclusions and recommendations for further research are drawn. As shown, data fusion from GPS, GLONASS, Galileo and BeiDou systems is becoming increasingly significant nowadays resulting in a position accuracy increase (mostly in the less favorable East direction) and a large reduction of convergence

  18. Evaluation of the accuracy of the microplate Alamar Blue assay for rapid detection of MDR-TB in Peru.

    Science.gov (United States)

    Chauca, J A; Palomino, J-C; Guerra, H

    2007-07-01

    Tuberculosis control is hampered by the widespread increase in multidrug resistance. Rapid drug susceptibility testing would greatly aid in the adequate treatment of the disease. This study evaluates the usefulness of the colorimetric method using Alamar Blue for the rapid detection of resistance to rifampicin and isoniazid in 63 clinical isolates of Mycobacterium tuberculosis in Peru. Results obtained by receiver operating characteristic curve analysis and measures of gain in certainty showed greater diagnostic accuracy than with the gold standard, the proportion method on Löwenstein-Jensen medium.

  19. Improved radioenzymatic assay for plasma norepinephrine using purified phenylethanolamine n-methyltransferase

    Energy Technology Data Exchange (ETDEWEB)

    Bowsher, R.R.; Henry, D.P.

    1986-03-01

    Radioenzymatic assays have been developed for catecholamines using either catechol O-methyltransferase (COMT) or phenylethanolamine N-methyltransferase (PNMT). Assays using PNMT are specific for norepinephrine (NE) and require minimal manipulative effort but until now have been less sensitive than the more complex procedures using COMT. The authors report an improved purification scheme for bovine PNMT which has permitted development of an NE assay with dramatically improved sensitivity (0.5 pg), specificity and reproducibility (C.V. < 5%). PNMT was purified by sequential pH 5.0 treatment and dialysis and by column chromatographic procedures using DEAE-Sephacel, Sepharcryl S-200 and Phenyl-Boronate Agarose. Recovery of PNMT through the purification scheme was 50%, while blank recovery was <.001%. NE can be directly quantified in 25 ul of human plasma and an 80 tube assay can be completed within 4 h. The capillary to venous plasma NE gradient was examined in 8 normotensive male subjects. Capillary plasma (NE (211.2 +/- 61.3 pg/ml)) was lower than venous plasma NE (366.6 +/- 92.5 pg/ml) in all subjects (p < 0.005). This difference suggests that capillary (NE) may be a unique indicator of sympathetic nervous system activity in vivo. In conclusion, purification of PNMT has facilitated development of an improved radioenzymatic for NE with significantly improved sensitivity.

  20. Development of an RSA calibration system with improved accuracy and precision.

    Science.gov (United States)

    Cai, Rongyi; Yuan, Xunhua; Rorabeck, Cecil; Bourne, Robert B; Holdsworth, David W

    2008-01-01

    In this study, a new radiostereometric analysis (RSA) calibration cage was developed with the aim of improving the accuracy and precision of RSA. This development consisted of three steps: a numerical simulation technique was first used to design the new cage; a synthetic imaging method was then implemented to predict the performance of the designed cage before it was actually fabricated; and an experimental phantom test was finally conducted to verify the actual performance of the new cage and compare with two currently widely used cages. Accuracy was calculated as the 95% prediction intervals from regression analyses between the measured and actual displacements, and precision was defined as the standard deviation of repeated measurements. The final experimental phantom tests showed that the accuracy and precision of the new calibration cage were improved by about 40% over an existing biplanar cage and by about 70% compared to a uniplanar cage design. This new cage can be used with any skeletal joints, in either static or kinematic examination, which is helpful for the standardization of the RSA application.

  1. Improving alignment accuracy on homopolymer regions for semiconductor-based sequencing technologies.

    Science.gov (United States)

    Feng, Weixing; Zhao, Sen; Xue, Dingkai; Song, Fengfei; Li, Ziwei; Chen, Duojiao; He, Bo; Hao, Yangyang; Wang, Yadong; Liu, Yunlong

    2016-08-22

    Ion Torrent and Ion Proton are semiconductor-based sequencing technologies that feature rapid sequencing speed and low upfront and operating costs, thanks to the avoidance of modified nucleotides and optical measurements. Despite of these advantages, however, Ion semiconductor sequencing technologies suffer much reduced sequencing accuracy at the genomic loci with homopolymer repeats of the same nucleotide. Such limitation significantly reduces its efficiency for the biological applications aiming at accurately identifying various genetic variants. In this study, we propose a Bayesian inference-based method that takes the advantage of the signal distributions of the electrical voltages that are measured for all the homopolymers of a fixed length. By cross-referencing the length of homopolymers in the reference genome and the voltage signal distribution derived from the experiment, the proposed integrated model significantly improves the alignment accuracy around the homopolymer regions. Besides improving alignment accuracy on homopolymer regions for semiconductor-based sequencing technologies with the proposed model, similar strategies can also be used on other high-throughput sequencing technologies that share similar limitations.

  2. Improving Accuracy of Intrusion Detection Model Using PCA and optimized SVM

    Directory of Open Access Journals (Sweden)

    Sumaiya Thaseen Ikram

    2016-06-01

    Full Text Available Intrusion detection is very essential for providing security to different network domains and is mostly used for locating and tracing the intruders. There are many problems with traditional intrusion detection models (IDS such as low detection capability against unknown network attack, high false alarm rate and insufficient analysis capability. Hence the major scope of the research in this domain is to develop an intrusion detection model with improved accuracy and reduced training time. This paper proposes a hybrid intrusiondetection model by integrating the principal component analysis (PCA and support vector machine (SVM. The novelty of the paper is the optimization of kernel parameters of the SVM classifier using automatic parameter selection technique. This technique optimizes the punishment factor (C and kernel parameter gamma (γ, thereby improving the accuracy of the classifier and reducing the training and testing time. The experimental results obtained on the NSL KDD and gurekddcup dataset show that the proposed technique performs better with higher accuracy, faster convergence speed and better generalization. Minimum resources are consumed as the classifier input requires reduced feature set for optimum classification. A comparative analysis of hybrid models with the proposed model is also performed.

  3. An improved Bathocuproine assay for accurate valence identification and quantification of copper bound by biomolecules.

    Science.gov (United States)

    Chen, Dinglong; Darabedian, Narek; Li, Zhiqiang; Kai, Tianhan; Jiang, Dianlu; Zhou, Feimeng

    2016-03-15

    Copper is an essential metal in all organisms. Reliably quantifying and identifying the copper content and oxidation state is crucial, since the information is essential to understanding protein structure and function. Chromophoric ligands, such as Bathocuproine (BC) and its water-soluble analog, Bathocuproinedisulfonic acid (BCS), preferentially bind Cu(I) over Cu(II), and therefore have been widely used as optical probes to determine the oxidation state of copper bound by biomolecules. However, the BCS assay is commonly misused, leading to erroneous conclusions regarding the role of copper in biological processes. By measuring the redox potential of Cu(II)-BCS2 and conducting UV-vis absorption measurements in the presence of oxidizable amino acids, the thermodynamic origin of the potential artifacts becomes evident. The BCS assay was improved by introducing a strong Cu(II) chelator EDTA prior to the addition of BCS to prevent interference that might arise from Cu(II) present in the sample. The strong Cu(II) chelator rids of all the potential errors inherent in the conventional BCS assay. Applications of the improved assay to peptides and protein containing oxidizable amino acid residues confirm that free Cu(II) no longer leads to artifacts, thereby resolving issues related to this persistently misused colorimetric assay of Cu(I) in biological systems. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. An improved microtiter assay for evaluating anti-HIV-1 neutralizing antibodies from sera or plasma

    Directory of Open Access Journals (Sweden)

    Chen Yunyun

    2003-12-01

    Full Text Available Abstract Background The anti-HIV-1 neutralizing antibody assay is widely used in AIDS vaccine research and other experimental and clinical studies. The vital dye staining method applied in the detection of anti-HIV-1 neutralizing antibody has been used in many laboratories. However, the unknown factor(s in sera or plasma affected cell growth and caused protection when the tested sera or plasma was continuously maintained in cell culture. In addition, the poor solubility of neutral red in medium (such as RPMI-1640 also limited the use of this assay. Methods In this study, human T cell line C8166 was used as host cells, and 3-(4,5-Dimethyl-2-thiazolyl-2,5-diphenyl-2H-tetrazolium bromide (MTT instead of neutral red was used as vital dye. In order to avoid the effect of the unknown factor(s, the tested sera or plasma was removed by a washout procedure after initial 3–6 h culture in the assay. Result This new assay eliminated the effect of the tested sera or plasma on cell growth, improved the reliability of detection of anti-HIV-1 neutralizing antibody, and showed excellent agreement with the p24 antigen method. Conclusion The results suggest that the improved assay is relatively simple, highly duplicable, cost-effective, and well reliable for evaluating anti-HIV-1 neutralizing antibodies from sera or plasma.

  5. [Improvement of registration accuracy for navigated-control drill in mastoidectomy (autopilot)].

    Science.gov (United States)

    Strauss, G; Dittrich, E; Baumberger, C; Hofer, M; Strauss, M; Stopp, S; Koulechov, K; Dietz, A; Lüth, T

    2008-08-01

    The goal of this study is the improvement of the surgical accuracy of a navigate-controlled drill for mastoidectomy in a lab test. For lab tests an artificial model of the temporal bone with color-coded injury identification of the facial nerve (solution of 0.5 mm) was used. Two different registration methods were examined: (group 1) navigation bow with 4 integrated markers at the upper jaw; (group 2) landmark registration with 4 titanium micro screws. An optical navigation system was used. The targets were illustrated by 3 titanium screws within the range of the planum mastoideum. The accuracy of the navigate-controlled drill in drilling the planned cavity were evaluated at 20 temporal bone models. The measurement of the registration accuracy was evaluated by deviation between the target screw and the calculated position in the navigation system. The evaluation of the resulted cavities was done by 5 senior surgeons with the help of the microscope. The registration accuracy shows a maximum deviation between the real position and the calculated position of 1,73 MM in group of 1 and 0.93 MM in group 2. In group 1 the nerve was hurt in 5/20 cases and a maximum deviation of - 1.5 mm (Std 0.25 mm) (drilled beyond the nerve) was measured. In group 2 the nerve was not hurt, a maximum deviation of 0.5 mm (too early stopped before the nerve) was measured. Significantly better results of the registration and drilling accuracy show up in group group 2. Thus the preconditions for clinical use are fulfilled.

  6. Early-Onset Neonatal Sepsis: Still Room for Improvement in Procalcitonin Diagnostic Accuracy Studies

    Science.gov (United States)

    Chiesa, Claudio; Pacifico, Lucia; Osborn, John F.; Bonci, Enea; Hofer, Nora; Resch, Bernhard

    2015-01-01

    Abstract To perform a systematic review assessing accuracy and completeness of diagnostic studies of procalcitonin (PCT) for early-onset neonatal sepsis (EONS) using the Standards for Reporting of Diagnostic Accuracy (STARD) initiative. EONS, diagnosed during the first 3 days of life, remains a common and serious problem. Increased PCT is a potentially useful diagnostic marker of EONS, but reports in the literature are contradictory. There are several possible explanations for the divergent results including the quality of studies reporting the clinical usefulness of PCT in ruling in or ruling out EONS. We systematically reviewed PubMed, Scopus, and the Cochrane Library databases up to October 1, 2014. Studies were eligible for inclusion in our review if they provided measures of PCT accuracy for diagnosing EONS. A data extraction form based on the STARD checklist and adapted for neonates with EONS was used to appraise the quality of the reporting of included studies. We found 18 articles (1998–2014) fulfilling our eligibility criteria which were included in the final analysis. Overall, the results of our analysis showed that the quality of studies reporting diagnostic accuracy of PCT for EONS was suboptimal leaving ample room for improvement. Information on key elements of design, analysis, and interpretation of test accuracy were frequently missing. Authors should be aware of the STARD criteria before starting a study in this field. We welcome stricter adherence to this guideline. Well-reported studies with appropriate designs will provide more reliable information to guide decisions on the use and interpretations of PCT test results in the management of neonates with EONS. PMID:26222858

  7. A New Approach to Improve Accuracy of Grey Model GMC(1,n in Time Series Prediction

    Directory of Open Access Journals (Sweden)

    Sompop Moonchai

    2015-01-01

    Full Text Available This paper presents a modified grey model GMC(1,n for use in systems that involve one dependent system behavior and n-1 relative factors. The proposed model was developed from the conventional GMC(1,n model in order to improve its prediction accuracy by modifying the formula for calculating the background value, the system of parameter estimation, and the model prediction equation. The modified GMC(1,n model was verified by two cases: the study of forecasting CO2 emission in Thailand and forecasting electricity consumption in Thailand. The results demonstrated that the modified GMC(1,n model was able to achieve higher fitting and prediction accuracy compared with the conventional GMC(1,n and D-GMC(1,n models.

  8. Pairwise adaptive thermostats for improved accuracy and stability in dissipative particle dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Leimkuhler, Benedict, E-mail: b.leimkuhler@ed.ac.uk; Shang, Xiaocheng, E-mail: x.shang@brown.edu

    2016-11-01

    We examine the formulation and numerical treatment of dissipative particle dynamics (DPD) and momentum-conserving molecular dynamics. We show that it is possible to improve both the accuracy and the stability of DPD by employing a pairwise adaptive Langevin thermostat that precisely matches the dynamical characteristics of DPD simulations (e.g., autocorrelation functions) while automatically correcting thermodynamic averages using a negative feedback loop. In the low friction regime, it is possible to replace DPD by a simpler momentum-conserving variant of the Nosé–Hoover–Langevin method based on thermostatting only pairwise interactions; we show that this method has an extra order of accuracy for an important class of observables (a superconvergence result), while also allowing larger timesteps than alternatives. All the methods mentioned in the article are easily implemented. Numerical experiments are performed in both equilibrium and nonequilibrium settings; using Lees–Edwards boundary conditions to induce shear flow.

  9. Has the accuracy of energy projections in OECD countries improved since the 1970s?

    DEFF Research Database (Denmark)

    Bentzen, Jan Børsen; Linderoth, Hans

    2001-01-01

    Since the 1970s, almost all OECD countries have published projections or forecasts of future energy consumption. By now, three decades later, the actual values of energy consumption are available for the same number of countries and thus a considerable amount of empirical data is available...... concerning formal hypothesis testing - e.g. whether there have been improvements in forecasting accuracy during this period. Using data for 16 OECD countries, the empirical evidence weakly favours the hypothesis that these countries have made some advances in forecasting accuracy, with regard to projections...... of energy consumption at the aggregate level and, to a lesser degree, at sectoral levels. Also, in accordance with a priori expectations, the forecasting failure increases with the length of the forecasting horizon....

  10. An Initial Study of Airport Arrival Heinz Capacity Benefits Due to Improved Scheduling Accuracy

    Science.gov (United States)

    Meyn, Larry; Erzberger, Heinz

    2005-01-01

    The long-term growth rate in air-traffic demand leads to future air-traffic densities that are unmanageable by today's air-traffic control system. I n order to accommodate such growth, new technology and operational methods will be needed in the next generation air-traffic control system. One proposal for such a system is the Automated Airspace Concept (AAC). One of the precepts of AAC is to direct aircraft using trajectories that are sent via an air-ground data link. This greatly improves the accuracy in directing aircraft to specific waypoints at specific times. Studies of the Center-TRACON Automation System (CTAS) have shown that increased scheduling accuracy enables increased arrival capacity at CTAS equipped airports.

  11. Automated auditory mismatch negativity paradigm improves coma prognostic accuracy after cardiac arrest and therapeutic hypothermia.

    Science.gov (United States)

    Rossetti, Andrea O; Tzovara, Athina; Murray, Micah M; De Lucia, Marzia; Oddo, Mauro

    2014-08-01

    EEG and somatosensory evoked potential are highly predictive of poor outcome after cardiac arrest; their accuracy for good recovery is however low. We evaluated whether addition of an automated mismatch negativity-based auditory discrimination paradigm (ADP) to EEG and somatosensory evoked potential improves prediction of awakening. EEG and ADP were prospectively recorded in 30 adults during therapeutic hypothermia and in normothermia. We studied the progression of auditory discrimination on single-trial multivariate analyses from therapeutic hypothermia to normothermia, and its correlation to outcome at 3 months, assessed with cerebral performance categories. At 3 months, 18 of 30 patients (60%) survived; 5 had severe neurologic impairment (cerebral performance categories = 3) and 13 had good recovery (cerebral performance categories = 1-2). All 10 subjects showing improvements of auditory discrimination from therapeutic hypothermia to normothermia regained consciousness: ADP was 100% predictive for awakening. The addition of ADP significantly improved mortality prediction (area under the curve, 0.77 for standard model including clinical examination, EEG, somatosensory evoked potential, versus 0.86 after adding ADP, P = 0.02). This automated ADP significantly improves early coma prognostic accuracy after cardiac arrest and therapeutic hypothermia. The progression of auditory discrimination is strongly predictive of favorable recovery and appears complementary to existing prognosticators of poor outcome. Before routine implementation, validation on larger cohorts is warranted.

  12. A multiple local models approach to accuracy improvement in continuous glucose monitoring.

    Science.gov (United States)

    Barceló-Rico, Fátima; Bondia, Jorge; Díez, José Luis; Rossetti, Paolo

    2012-01-01

    Continuous glucose monitoring (CGM) devices estimate plasma glucose (PG) from measurements in compartments alternative to blood. The accuracy of currently available CGM is yet unsatisfactory and may depend on the implemented calibration algorithms, which do not compensate adequately for the differences of glucose dynamics between the compartments. Here we propose and validate an innovative calibration algorithm for the improvement of CGM performance. CGM data from GlucoDay(®) (A. Menarini, Florence, Italy) and paired reference PG have been obtained from eight subjects without diabetes during eu-, hypo-, and hyperglycemic hyperinsulinemic clamps. A calibration algorithm based on a dynamic global model (GM) of the relationship between PG and CGM in the interstitial space has been obtained. The GM is composed by independent local models (LMs) weighted and added. LMs are defined by a combination of inputs from the CGM and by a validity function, so that each LM represents to a variable extent a different metabolic condition and/or sensor-subject interaction. The inputs best suited for glucose estimation were the sensor current I and glucose estimations Ĝ, at different time instants [I(k), I(k)(-1), Ĝ(k)(-1)] (IIG). In addition to IIG, other inputs have been used to obtain the GM, achieving different configurations of the calibration algorithm. Even in its simplest configuration considering only IIG, the new calibration algorithm improved the accuracy of the estimations compared with the manufacturer's estimate: mean absolute relative difference (MARD)=10.8±1.5% versus 14.7±5.4%, respectively (P=0.012, by analysis of variance). When additional exogenous signals were considered, the MARD improved further (7.8±2.6%, Palgorithm improves the accuracy of PG estimations.

  13. Kinematic Visual Biofeedback Improves Accuracy of Learning a Swallowing Maneuver and Accuracy of Clinician Cues During Training.

    Science.gov (United States)

    Azola, Alba M; Sunday, Kirstyn L; Humbert, Ianessa A

    2017-02-01

    Submental surface electromyography (ssEMG) visual biofeedback is widely used to train swallowing maneuvers. This study compares the effect of ssEMG and videofluoroscopy (VF) visual biofeedback on hyo-laryngeal accuracy when training a swallowing maneuver. Furthermore, it examines the clinician's ability to provide accurate verbal cues during swallowing maneuver training. Thirty healthy adults performed the volitional laryngeal vestibule closure maneuver (vLVC), which involves swallowing and sustaining closure of the laryngeal vestibule for 2 s. The study included two stages: (1) first accurate demonstration of the vLVC maneuver, followed by (2) training-20 vLVC training swallows. Participants were randomized into three groups: (a) ssEMG biofeedback only, (b) VF biofeedback only, and (c) mixed biofeedback (VF for the first accurate demonstration achieving stage and ssEMG for the training stage). Participants' performances were verbally critiqued or reinforced in real time while both the clinician and participant were observing the assigned visual biofeedback. VF and ssEMG were continuously recorded for all participants. Results show that accuracy of both vLVC performance and clinician cues was greater with VF biofeedback than with either ssEMG or mixed biofeedback (p < 0.001). Using ssEMG for providing real-time biofeedback during training could lead to errors while learning and training a swallowing maneuver.

  14. Diagnostic accuracy and comparison of two assays for Borrelia-specific IgG and IgM antibodies

    DEFF Research Database (Denmark)

    Dessau, Ram

    2013-01-01

    to represent the serological response of disseminated early Lyme borreliosis in general. Serum samples were obtained from 216 Danish blood donors as controls. By comparing sensitivity and specificity using pre-specified cut-off values, significant differences were found. However, using receiver operating......C/VlsE IgM assay, the specificity was decreased without a gain in sensitivity. This study proposes standardizing of reporting by using a control population as the reference and choosing decision thresholds guided by the risk of false-positive results at 2 and 8 %. The sensitivities for IDEIA (IgG and Ig...... ability to distinguish serum samples from patients with neuroborreliosis from blood donor controls. However, cut-off values should be adjusted for a proper comparison....

  15. Comparison of loop-mediated isothermal amplification assay and smear microscopy with culture for the diagnostic accuracy of tuberculosis.

    Science.gov (United States)

    Gelaw, Baye; Shiferaw, Yitayal; Alemayehu, Marta; Bashaw, Abate Assefa

    2017-01-17

    Tuberculosis (TB) caused by Mycobacterium tuberculosis is one of the leading causes of death from infectious diseases worldwide. Sputum smear microscopy remains the most widely available pulmonary TB diagnostic tool particularly in resource limited settings. A highly sensitive diagnostic with minimal infrastructure, cost and training is required. Hence, we assessed the diagnostic performance of Loop-mediated isothermal amplification (LAMP) assay in detecting M.tuberculosis infection in sputum sample compared to LED fluorescent smear microscopy and culture. A cross-sectional study was conducted at the University of Gondar Hospital from June 01, 2015 to August 30, 2015. Pulmonary TB diagnosis using sputum LED fluorescence smear microscopy, TB-LAMP assay and culture were done. A descriptive analysis was used to determine demographic characteristics of the study participants. Analysis of sensitivity and specificity for smear microscopy and TB-LAMP compared with culture as a reference test was performed. Cohen's kappa was calculated as a measure of agreement between the tests. A total of 78 pulmonary presumptive TB patients sputum sample were analyzed. The overall sensitivity and specificity of LAMP were 75 and 98%, respectively. Among smear negative sputum samples, 33.3% sensitivity and 100% specificity of LAMP were observed. Smear microscopy showed 78.6% sensitivity and 98% specificity. LAMP and smear in series had sensitivity of 67.8% and specificity of 100%. LAMP and smear in parallel had sensitivity of 85.7% and specificity of 96%. The agreement between LAMP and fluorescent smear microscopy tests was very good (κ = 0.83, P-value ≤0.0001). TB-LAMP showed similar specificity but a slightly lower sensitivity with LED fluorescence microscopy. The specificity of LAMP and smear microscopy in series was high. The sensitivity of LAMP was insufficient for smear negative sputum samples.

  16. Improved precision and accuracy for microarrays using updated probe set definitions

    Directory of Open Access Journals (Sweden)

    Larsson Ola

    2007-02-01

    Full Text Available Abstract Background Microarrays enable high throughput detection of transcript expression levels. Different investigators have recently introduced updated probe set definitions to more accurately map probes to our current knowledge of genes and transcripts. Results We demonstrate that updated probe set definitions provide both better precision and accuracy in probe set estimates compared to the original Affymetrix definitions. We show that the improved precision mainly depends on the increased number of probes that are integrated into each probe set, but we also demonstrate an improvement when the same number of probes is used. Conclusion Updated probe set definitions does not only offer expression levels that are more accurately associated to genes and transcripts but also improvements in the estimated transcript expression levels. These results give support for the use of updated probe set definitions for analysis and meta-analysis of microarray data.

  17. An improved high-throughput screening assay for tunicamycin sensitivity in Arabidopsis seedlings

    Directory of Open Access Journals (Sweden)

    Maggie E McCormack

    2015-08-01

    Full Text Available Tunicamycin sensitivity assays are a useful method for studies of endoplasmic reticulum stress and the unfolded protein response in eukaryotic cells. While tunicamycin sensitivity and tunicamycin recovery assays have been previously described, these existing methods are time-consuming, labor intensive and subjected to mechanical wounding. This study shows an improved method of testing tunicamycin sensitivity in Arabidopsis using liquid Murashige and Skoog medium versus the traditional solid agar plates. Liquid medium bypasses the physical manipulation of seedlings, thereby eliminating the risk of potential mechanical damage and additional unwanted stress to seedlings. Seedlings were subjected to comparative treatments with various concentrations of tunicamycin on both solid and liquid media and allowed to recover. Determination of fresh weight, chlorophyll contents analysis and qRT-PCR results confirm the efficacy of using liquid medium to perform quantitative tunicamycin stress assays.

  18. Accuracy improvement of a hybrid robot for ITER application using POE modeling method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yongbo, E-mail: yongbo.wang@hotmail.com [Laboratory of Intelligent Machines, Lappeenranta University of Technology, FIN-53851 Lappeenranta (Finland); Wu, Huapeng; Handroos, Heikki [Laboratory of Intelligent Machines, Lappeenranta University of Technology, FIN-53851 Lappeenranta (Finland)

    2013-10-15

    Highlights: ► The product of exponential (POE) formula for error modeling of hybrid robot. ► Differential Evolution (DE) algorithm for parameter identification. ► Simulation results are given to verify the effectiveness of the method. -- Abstract: This paper focuses on the kinematic calibration of a 10 degree-of-freedom (DOF) redundant serial–parallel hybrid robot to improve its accuracy. The robot was designed to perform the assembling and repairing tasks of the vacuum vessel (VV) of the international thermonuclear experimental reactor (ITER). By employing the product of exponentials (POEs) formula, we extended the POE-based calibration method from serial robot to redundant serial–parallel hybrid robot. The proposed method combines the forward and inverse kinematics together to formulate a hybrid calibration method for serial–parallel hybrid robot. Because of the high nonlinear characteristics of the error model and too many error parameters need to be identified, the traditional iterative linear least-square algorithms cannot be used to identify the parameter errors. This paper employs a global optimization algorithm, Differential Evolution (DE), to identify parameter errors by solving the inverse kinematics of the hybrid robot. Furthermore, after the parameter errors were identified, the DE algorithm was adopted to numerically solve the forward kinematics of the hybrid robot to demonstrate the accuracy improvement of the end-effector. Numerical simulations were carried out by generating random parameter errors at the allowed tolerance limit and generating a number of configuration poses in the robot workspace. Simulation of the real experimental conditions shows that the accuracy of the end-effector can be improved to the same precision level of the given external measurement device.

  19. [Improving the Accuracy Rate of Analgesics and Sedatives Administration in an Intensive Care Unit].

    Science.gov (United States)

    Lai, Hsiu-Chuan; Chen, Ya-Huei; Li, Yi-Jene; Huang, Hui-Mei; Tseng, Chien-Hua; Chan, Ming-Cheng

    2017-12-01

    Patients with respiratory failure needing mechanical ventilation are common in the intensive care unit. These patients often require sedative and analgesic agents to alleviate their discomfort and to avoid causing associated safety issues. However, prolonged post-awakening confusion and changes in perception after withdrawal from sedatives and analgesic agents are common in daily practice. Thus, the optimal use of sedative and analgesic agents remains an important issue in the intensive care unit. To optimize sedation by raising the rate of accuracy for administering analgesic and sedative agents in the intensive care unit from 30.44% to 60.88%. We first analyzed the problem from the current situation of the daily practice and revised the protocol of using analgesic and sedative agents. In order to achieve an optimal outcome, the authors further arranged staff education and bedside training and established an audit system to check and improve protocol adherence. The rate of accuracy for administering sedatives and analgesics improved from 34% to 93%. With appropriately scaled protocols of sedatives and analgesics administration, intensive care nurses may easily target the consistent and optimal assessment and provide pain relief prior to sedation, which will improve the quality of sedation and patient safety.

  20. Sleep extension improves serving accuracy: A study with college varsity tennis players.

    Science.gov (United States)

    Schwartz, Jennifer; Simon, Richard D

    2015-11-01

    This study investigated the effects of sleep extension on tennis serving accuracy, as well as daytime sleepiness in college varsity tennis players. Twelve (seven females and five males) healthy students on a college varsity tennis team maintained their habitual sleep-wake schedule for a one-week baseline period followed by a one-week sleep extension period. Participants were requested to sleep at least nine hours, including naps, during the sleep extension period. Serving accuracy was assessed when participants were sleep deprived (prior to the sleep extension period) and after the sleep extension period. Levels of daytime sleepiness were monitored via the Epworth Sleepiness Scale and the Stanford Sleepiness Scale, and caffeine consumption was recorded throughout the study. Participants slept significantly more in the second week--the sleep extension week--compared with the first week--the baseline week (8.85 vs. 7.14 h; psleep extension period, accuracy of the tennis serves improved significantly (35.7% vs. 41.8%; psleep of approximately 2h per night significantly increased athletic performance in college varsity tennis players. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Improvement in precision, accuracy, and efficiency in sstandardizing the characterization of granular materials

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, Jonathan R. [ORISE; Shadle, Lawrence J. [U.S. DOE; Benyahia, Sofiane [U.S. DOE; Mei, Joseph [U.S. DOE; Guenther, Chris [U.S. DOE; Koepke, M. E. [WVU

    2013-01-01

    Useful prediction of the kinematics, dynamics, and chemistry of a system relies on precision and accuracy in the quantification of component properties, operating mechanisms, and collected data. In an attempt to emphasize, rather than gloss over, the benefit of proper characterization to fundamental investigations of multiphase systems incorporating solid particles, a set of procedures were developed and implemented for the purpose of providing a revised methodology having the desirable attributes of reduced uncertainty, expanded relevance and detail, and higher throughput. Better, faster, cheaper characterization of multiphase systems result. Methodologies are presented to characterize particle size, shape, size distribution, density (particle, skeletal and bulk), minimum fluidization velocity, void fraction, particle porosity, and assignment within the Geldart Classification. A novel form of the Ergun equation was used to determine the bulk void fractions and particle density. Accuracy of properties-characterization methodology was validated on materials of known properties prior to testing materials of unknown properties. Several of the standard present-day techniques were scrutinized and improved upon where appropriate. Validity, accuracy, and repeatability were assessed for the procedures presented and deemed higher than present-day techniques. A database of over seventy materials has been developed to assist in model validation efforts and future desig

  2. A novel method for improving the accuracy of coordinate transformation in multiple measurement systems

    Science.gov (United States)

    Liu, W. L.; Li, Y. W.

    2017-09-01

    Large-scale dimensional metrology usually requires a combination of multiple measurement systems, such as laser tracking, total station, laser scanning, coordinate measuring arm and video photogrammetry, etc. Often, the results from different measurement systems must be combined to provide useful results. The coordinate transformation is used to unify coordinate frames in combination; however, coordinate transformation uncertainties directly affect the accuracy of the final measurement results. In this paper, a novel method is proposed for improving the accuracy of coordinate transformation, combining the advantages of the best-fit least-square and radial basis function (RBF) neural networks. First of all, the configuration of coordinate transformation is introduced and a transformation matrix containing seven variables is obtained. Second, the 3D uncertainty of the transformation model and the residual error variable vector are established based on the best-fit least-square. Finally, in order to optimize the uncertainty of the developed seven-variable transformation model, we used the RBF neural network to identify the uncertainty of the dynamic, and unstructured, owing to its great ability to approximate any nonlinear function to the designed accuracy. Intensive experimental studies were conducted to check the validity of the theoretical results. The results show that the mean error of coordinate transformation decreased from 0.078 mm to 0.054 mm after using this method in contrast with the GUM method.

  3. Oxygen permeability measurements of contact lenses: a proposal for accuracy improvement.

    Science.gov (United States)

    D'Avenio, Giuseppe; Poli, Cecilia; Daniele, Carla; Grigioni, Mauro

    2013-01-01

    Contact lens are a widespread medical device. In view of the importance of a proper oxygenation of the cornea, new materials are continuously being tested, with a high permeability to oxygen. Taking into account the limitations of the methods for testing soft contact lenses, as presented in the relevant international standards, this paper focuses on the polarographic method and on the approach of measuring oxygen permeability of stacked contact lenses. The effect of the interspersed saline solution layers on the measurable permeability of the stack is considered, using Fick's law of diffusive flux, and a proposal for accuracy improvement in oxygen permeability measurements is presented.

  4. Accuracy Improvement for Light-Emitting-Diode-Based Colorimeter by Iterative Algorithm

    Science.gov (United States)

    Yang, Pao-Keng

    2011-09-01

    We present a simple algorithm, combining an interpolating method with an iterative calculation, to enhance the resolution of spectral reflectance by removing the spectral broadening effect due to the finite bandwidth of the light-emitting diode (LED) from it. The proposed algorithm can be used to improve the accuracy of a reflective colorimeter using multicolor LEDs as probing light sources and is also applicable to the case when the probing LEDs have different bandwidths in different spectral ranges, to which the powerful deconvolution method cannot be applied.

  5. Color camera computed tomography imaging spectrometer for improved spatial-spectral image accuracy

    Science.gov (United States)

    Wilson, Daniel W. (Inventor); Bearman, Gregory H. (Inventor); Johnson, William R. (Inventor)

    2011-01-01

    Computed tomography imaging spectrometers ("CTIS"s) having color focal plane array detectors are provided. The color FPA detector may comprise a digital color camera including a digital image sensor, such as a Foveon X3.RTM. digital image sensor or a Bayer color filter mosaic. In another embodiment, the CTIS includes a pattern imposed either directly on the object scene being imaged or at the field stop aperture. The use of a color FPA detector and the pattern improves the accuracy of the captured spatial and spectral information.

  6. Accuracy of a rapid real-time polymerase chain reaction assay for diagnosis of group B Streptococcus colonization in a cohort of HIV-infected pregnant women.

    Science.gov (United States)

    Gouvea, Maria Isabel S; Joao, Esau C; Teixeira, Maria de Lourdes B; Read, Jennifer S; Fracalanzza, Sergio E L; Souza, Claudia T V; Souza, Maria José de; Torres Filho, Helio M; Leite, Cassiana C F; do Brasil, Pedro E A A

    2017-05-01

    There are limited data regarding Xpert performance to detect Group B Streptococcus (GBS) in HIV-infected pregnant women. We evaluated the accuracy of a rapid real-time polymerase chain reaction (PCR) test in a cohort of HIV-infected women. At 35-37 weeks of pregnancy, a pair of combined rectovaginal swabs were collected for two GBS assays in a cohort of sequentially included HIV-infected women in Rio de Janeiro: (1) culture; and (2) real-time PCR assay [GeneXpert GBS (Cepheid, Sunnyvale, CA)]. Using culture as the reference, sensitivity, specificity, positive and negative-likelihood ratios were estimated. From June 2012 to February 2015, 337 pregnant women met inclusion criteria. One woman was later excluded, due to failure to obtain a result in the index test; 336 were included in the analyses. The GBS colonization rate was 19.04%. Sensitivity and specificity of the GeneXpert GBS assay were 85.94% (95% CI: 75.38-92.42) and 94.85% (95% CI: 91.55-96.91), respectively. Positive and negative predictive values were 79.71% (95% CI: 68.78-87.51) and 96.63% (95% CI: 93.72-98.22), respectively. GeneXpert GBS is an acceptable test for the identification of GBS colonization in HIV-infected pregnant women and represents a reasonable option to detect GBS colonization in settings where culture is not feasible.

  7. Occupational exposure decisions: can limited data interpretation training help improve accuracy?

    Science.gov (United States)

    Logan, Perry; Ramachandran, Gurumurthy; Mulhausen, John; Hewett, Paul

    2009-06-01

    Accurate exposure assessments are critical for ensuring that potentially hazardous exposures are properly identified and controlled. The availability and accuracy of exposure assessments can determine whether resources are appropriately allocated to engineering and administrative controls, medical surveillance, personal protective equipment and other programs designed to protect workers. A desktop study was performed using videos, task information and sampling data to evaluate the accuracy and potential bias of participants' exposure judgments. Desktop exposure judgments were obtained from occupational hygienists for material handling jobs with small air sampling data sets (0-8 samples) and without the aid of computers. In addition, data interpretation tests (DITs) were administered to participants where they were asked to estimate the 95th percentile of an underlying log-normal exposure distribution from small data sets. Participants were presented with an exposure data interpretation or rule of thumb training which included a simple set of rules for estimating 95th percentiles for small data sets from a log-normal population. DIT was given to each participant before and after the rule of thumb training. Results of each DIT and qualitative and quantitative exposure judgments were compared with a reference judgment obtained through a Bayesian probabilistic analysis of the sampling data to investigate overall judgment accuracy and bias. There were a total of 4386 participant-task-chemical judgments for all data collections: 552 qualitative judgments made without sampling data and 3834 quantitative judgments with sampling data. The DITs and quantitative judgments were significantly better than random chance and much improved by the rule of thumb training. In addition, the rule of thumb training reduced the amount of bias in the DITs and quantitative judgments. The mean DIT % correct scores increased from 47 to 64% after the rule of thumb training (P rule of thumb

  8. Improving virtual screening predictive accuracy of Human kallikrein 5 inhibitors using machine learning models.

    Science.gov (United States)

    Fang, Xingang; Bagui, Sikha; Bagui, Subhash

    2017-08-01

    The readily available high throughput screening (HTS) data from the PubChem database provides an opportunity for mining of small molecules in a variety of biological systems using machine learning techniques. From the thousands of available molecular descriptors developed to encode useful chemical information representing the characteristics of molecules, descriptor selection is an essential step in building an optimal quantitative structural-activity relationship (QSAR) model. For the development of a systematic descriptor selection strategy, we need the understanding of the relationship between: (i) the descriptor selection; (ii) the choice of the machine learning model; and (iii) the characteristics of the target bio-molecule. In this work, we employed the Signature descriptor to generate a dataset on the Human kallikrein 5 (hK 5) inhibition confirmatory assay data and compared multiple classification models including logistic regression, support vector machine, random forest and k-nearest neighbor. Under optimal conditions, the logistic regression model provided extremely high overall accuracy (98%) and precision (90%), with good sensitivity (65%) in the cross validation test. In testing the primary HTS screening data with more than 200K molecular structures, the logistic regression model exhibited the capability of eliminating more than 99.9% of the inactive structures. As part of our exploration of the descriptor-model-target relationship, the excellent predictive performance of the combination of the Signature descriptor and the logistic regression model on the assay data of the Human kallikrein 5 (hK 5) target suggested a feasible descriptor/model selection strategy on similar targets. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Toxoplasma gondii plaque assays revisited: Improvements for ultrastructural and quantitative evaluation of lytic parasite growth.

    Science.gov (United States)

    Ufermann, Christoph-Martin; Müller, Florian; Frohnecke, Nora; Laue, Michael; Seeber, Frank

    2017-09-01

    Lytic growth of intracellular Toxoplasma gondii tachyzoite stages over a period of days results in plaques within mononolayers of host cells. Plaque assays are in frequent use to isolate single clones and to investigate invasion, replication and egress over a longer time frame. To allow correlating plaque morphology and/or size with ultrastructural examination of individual parasites we introduce a simple protocol for correlative light and electron microscopy (CLEM) of entire plaques. We also illustrate the advantages of visualizing only the boundaries of plaques by staining for infected cells ('positive staining') rather than the traditional staining of the intact cell monolayer, thus outlining the area of lysed cells ('negative staining'). Tachyzoites expressing β-galactosidase of Escherichia coli are an easy to visualize histochemical marker for this purpose. Quantitative measurements of plaque area with our compiled user-friendly ImageJ macros are compared to commercial software for ease and shown to be more accurate for some applications. Finally, a chemically defined medium is shown to be superior to the fetal bovine serum-containing medium for plaque assays, resulting in larger plaques. The reported additions and changes of the plaque assay procedure offer improved ways to analyze subtle differences in invasion, pathogen growth and egress. Our chemically defined medium will improve standardization of e.g. drug screening assays. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Improving the accuracy of admitted subacute clinical costing: an action research approach.

    Science.gov (United States)

    Hakkennes, Sharon; Arblaster, Ross; Lim, Kim

    2017-08-01

    Objective The aim of the present study was to determine whether action research could be used to improve the breadth and accuracy of clinical costing data in an admitted subacute setting Methods The setting was a 100-bed in-patient rehabilitation centre. Using a pre-post study design all admitted subacute separations during the 2011-12 financial year were eligible for inclusion. An action research framework aimed at improving clinical costing methodology was developed and implemented. Results In all, 1499 separations were included in the study. A medical record audit of a random selection of 80 separations demonstrated that the use of an action research framework was effective in improving the breadth and accuracy of the costing data. This was evidenced by a significant increase in the average number of activities costed, a reduction in the average number of activities incorrectly costed and a reduction in the average number of activities missing from the costing, per episode of care. Conclusions Engaging clinicians and cost centre managers was effective in facilitating the development of robust clinical costing data in an admitted subacute setting. Further investigation into the value of this approach across other care types and healthcare services is warranted. What is known about this topic? Accurate clinical costing data is essential for informing price models used in activity-based funding. In Australia, there is currently a lack of robust admitted subacute cost data to inform the price model for this care type. What does this paper add? The action research framework presented in this study was effective in improving the breadth and accuracy of clinical costing data in an admitted subacute setting. What are the implications for practitioners? To improve clinical costing practices, health services should consider engaging key stakeholders, including clinicians and cost centre managers, in reviewing clinical costing methodology. Robust clinical costing data has

  11. Improving accuracy for cancer classification with a new algorithm for genes selection

    Directory of Open Access Journals (Sweden)

    Zhang Hongyan

    2012-11-01

    Full Text Available Abstract Background Even though the classification of cancer tissue samples based on gene expression data has advanced considerably in recent years, it faces great challenges to improve accuracy. One of the challenges is to establish an effective method that can select a parsimonious set of relevant genes. So far, most methods for gene selection in literature focus on screening individual or pairs of genes without considering the possible interactions among genes. Here we introduce a new computational method named the Binary Matrix Shuffling Filter (BMSF. It not only overcomes the difficulty associated with the search schemes of traditional wrapper methods and overfitting problem in large dimensional search space but also takes potential gene interactions into account during gene selection. This method, coupled with Support Vector Machine (SVM for implementation, often selects very small number of genes for easy model interpretability. Results We applied our method to 9 two-class gene expression datasets involving human cancers. During the gene selection process, the set of genes to be kept in the model was recursively refined and repeatedly updated according to the effect of a given gene on the contributions of other genes in reference to their usefulness in cancer classification. The small number of informative genes selected from each dataset leads to significantly improved leave-one-out (LOOCV classification accuracy across all 9 datasets for multiple classifiers. Our method also exhibits broad generalization in the genes selected since multiple commonly used classifiers achieved either equivalent or much higher LOOCV accuracy than those reported in literature. Conclusions Evaluation of a gene’s contribution to binary cancer classification is better to be considered after adjusting for the joint effect of a large number of other genes. A computationally efficient search scheme was provided to perform effective search in the extensive

  12. Improved Statistical Sampling and Accuracy with Accelerated Molecular Dynamics on Rotatable Torsions.

    Science.gov (United States)

    Doshi, Urmi; Hamelberg, Donald

    2012-11-13

    In enhanced sampling techniques, the precision of the reweighted ensemble properties is often decreased due to large variation in statistical weights and reduction in the effective sampling size. To abate this reweighting problem, here, we propose a general accelerated molecular dynamics (aMD) approach in which only the rotatable dihedrals are subjected to aMD (RaMD), unlike the typical implementation wherein all dihedrals are boosted (all-aMD). Nonrotatable and improper dihedrals are marginally important to conformational changes or the different rotameric states. Not accelerating them avoids the sharp increases in the potential energies due to small deviations from their minimum energy conformations and leads to improvement in the precision of RaMD. We present benchmark studies on two model dipeptides, Ace-Ala-Nme and Ace-Trp-Nme, simulated with normal MD, all-aMD, and RaMD. We carry out a systematic comparison between the performances of both forms of aMD using a theory that allows quantitative estimation of the effective number of sampled points and the associated uncertainty. Our results indicate that, for the same level of acceleration and simulation length, as used in all-aMD, RaMD results in significantly less loss in the effective sample size and, hence, increased accuracy in the sampling of φ-ψ space. RaMD yields an accuracy comparable to that of all-aMD, from simulation lengths 5 to 1000 times shorter, depending on the peptide and the acceleration level. Such improvement in speed and accuracy over all-aMD is highly remarkable, suggesting RaMD as a promising method for sampling larger biomolecules.

  13. Motion correction for improving the accuracy of dual-energy myocardial perfusion CT imaging

    Science.gov (United States)

    Pack, Jed D.; Yin, Zhye; Xiong, Guanglei; Mittal, Priya; Dunham, Simon; Elmore, Kimberly; Edic, Peter M.; Min, James K.

    2016-03-01

    Coronary Artery Disease (CAD) is the leading cause of death globally [1]. Modern cardiac computed tomography angiography (CCTA) is highly effective at identifying and assessing coronary blockages associated with CAD. The diagnostic value of this anatomical information can be substantially increased in combination with a non-invasive, low-dose, correlative, quantitative measure of blood supply to the myocardium. While CT perfusion has shown promise of providing such indications of ischemia, artifacts due to motion, beam hardening, and other factors confound clinical findings and can limit quantitative accuracy. In this paper, we investigate the impact of applying a novel motion correction algorithm to correct for motion in the myocardium. This motion compensation algorithm (originally designed to correct for the motion of the coronary arteries in order to improve CCTA images) has been shown to provide substantial improvements in both overall image quality and diagnostic accuracy of CCTA. We have adapted this technique for application beyond the coronary arteries and present an assessment of its impact on image quality and quantitative accuracy within the context of dual-energy CT perfusion imaging. We conclude that motion correction is a promising technique that can help foster the routine clinical use of dual-energy CT perfusion. When combined, the anatomical information of CCTA and the hemodynamic information from dual-energy CT perfusion should facilitate better clinical decisions about which patients would benefit from treatments such as stent placement, drug therapy, or surgery and help other patients avoid the risks and costs associated with unnecessary, invasive, diagnostic coronary angiography procedures.

  14. Accuracy of indirect haemagglutination and western blot assays for the detection of anti-Schistosoma antibodies in non-severe febrile patients in two Tanzanian hospitals.

    Science.gov (United States)

    Bevilacqua, Nazario; Pane, Stefania; Vairo, Francesco; Nicastri, Emanuele; Paglia, Maria G; Ame, Shaali M; Schepisi, Monica Sañé; Kitua, Andrew; Mangi, Sabina; Racalbuto, Vincenzo; Meschi, Silvia; Ippolito, Giuseppe

    2012-06-01

    The diagnosis of schistosomiasis is usually based on clinical data associated with the detection of eggs in stool, urine, and/or rectal and bladder biopsy specimens. However antibody detection can be useful to indicate Schistosoma infection in those for whom eggs cannot be demonstrated. The aim of this study was to assess the seroprevalence of schistosomiasis and to evaluate the accuracy of indirect haemagglutination (IHA) and Western blot (WB) assays for the detection of anti-Schistosoma antibodies in 2 peripheral hospitals of the United Republic of Tanzania. Between February and March 2007 blood samples were collected from 297 non-severe febrile outpatients who attended Chake Chake Hospital, Pemba Island and Tosamaganga Hospital, Iringa region in Tanzania. The samples were processed for Schistosoma antibodies by IHA and WB assays in Italy. Two hundred and sixty-two of 297 patients were schistosomiasis antibody-positive by IHA (88.2%). Of 142 patients positive by IHA, only 22 (12.4%) cases were confirmed by WB assay. The WB assay confirmed all 35 negative cases previously identified by IHA. The seroprevalence of Schistosoma at Chake Chake Hospital was lower than in Tosamaganga Hospital (9/97, 9.3% vs 13/80, 16.2%). Schistosomiasis is endemic in Tanzania, being more prevalent on the mainland than on Pemba Island. The implications of this study are of public health relevance and suggest the need for increased efforts in large-scale chemotherapy-based morbidity control programmes, integrated with those for other soil-transmitted helminthiases, in these 2 peripheral areas of the United Republic of Tanzania.

  15. Surgical Navigation Improves the Precision and Accuracy of Tibial Component Alignment in Canine Total Knee Replacement.

    Science.gov (United States)

    Peters, Kaleigh M; Hutter, Erin; Siston, Robert A; Bertran, Judith; Allen, Matthew J

    2016-01-01

    The goal of this study was to determine whether computer-assisted surgical navigation improves the accuracy of tibial component alignment in canine total knee replacement (TKR). Retrospective radiographic review and prospective ex vivo study. Canine TKR radiographs (n = 17 sets) and canine cadaveric stifles (n = 12). Radiographs from TKR surgical workshops were reviewed to determine the incidence and magnitude of tibial component malalignment. Tibial component alignment was compared after either standard ("surgeon-guided") component placement or computer-assisted ("navigation-guided") placement. Results were compared against the current recommendations of a neutral (0° varus-valgus) ostectomy in the frontal plane and 6° of caudal slope in the sagittal plane. A prospective cadaveric study was then undertaken by performing TKR in 12 canine stifle joints. Malalignment of >3° in the frontal and sagittal planes was identified in 12% and 24% of the radiographs from the retrospective review, respectively. Surgical navigation reduced both the mean error (P = .007) and the variability in frontal plane alignment (P canine TKR. Clinical trials would be required to determine whether these improvements in surgical accuracy lead to better clinical outcomes in terms of joint function and a reduction in long-term implant wear. © Copyright 2015 by The American College of Veterinary Surgeons.

  16. A method for improving the calculation accuracy of acid-base constants by inverse gas chromatography.

    Science.gov (United States)

    Shi, Baoli; Qi, Dawei

    2012-03-30

    In this paper, studies were conducted in order to improve the calculation accuracy of acid-base constants measured by inverse gas chromatography. The conventional a·(γ(d)(l))(0.5) parameters of DCM (dichloromethane), TCM (trichloromethane), and EtAcet (ethyl acetate) were corrected as 185, 212, and 235 Å(2)(mJ/m(2))(0.5) by analyzing the relationship between a·(γ(d)(l))(0.5) and the boiling temperature of the probe solvents, where a is molecular area and γ(l)(d) is surface dispersive free energy of the probe solvents, respectively. To validate the availability of the new a·(γ(d)(l))(0.5) values, the acid-base constants of polystyrene were measured. It was found that when the new a·(γ(d)(l))(0.5) parameters were adopted, the final linear fit degree for the plot of -ΔH(a)(s)/AN* versus DN/AN* was enhanced from 0.993 to 0.999, and the standard deviation was decreased from 0.344 to 0.156. In addition, the availability of general application to improving the calculation accuracy of acid-base constants with the new a·(γ(d)(l))(0.5) parameters was also proved with a mathematical justification. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Improving Intensity-Based Lung CT Registration Accuracy Utilizing Vascular Information

    Directory of Open Access Journals (Sweden)

    Kunlin Cao

    2012-01-01

    Full Text Available Accurate pulmonary image registration is a challenging problem when the lungs have a deformation with large distance. In this work, we present a nonrigid volumetric registration algorithm to track lung motion between a pair of intrasubject CT images acquired at different inflation levels and introduce a new vesselness similarity cost that improves intensity-only registration. Volumetric CT datasets from six human subjects were used in this study. The performance of four intensity-only registration algorithms was compared with and without adding the vesselness similarity cost function. Matching accuracy was evaluated using landmarks, vessel tree, and fissure planes. The Jacobian determinant of the transformation was used to reveal the deformation pattern of local parenchymal tissue. The average matching error for intensity-only registration methods was on the order of 1 mm at landmarks and 1.5 mm on fissure planes. After adding the vesselness preserving cost function, the landmark and fissure positioning errors decreased approximately by 25% and 30%, respectively. The vesselness cost function effectively helped improve the registration accuracy in regions near thoracic cage and near the diaphragm for all the intensity-only registration algorithms tested and also helped produce more consistent and more reliable patterns of regional tissue deformation.

  18. Combined algorithm for improvement of fused radar and optical data classification accuracy

    Science.gov (United States)

    Karimi, Danya; Rangzan, Kazem; Akbarizadeh, Gholamreza; Kabolizadeh, Mostafa

    2017-01-01

    A new method, MICO-LDASR, is proposed to improve the classification accuracy of fused radar and optical data. The proposed algorithm combines three algorithms: multiplicative intrinsic component optimization (MICO), linear discriminant analysis (LDA), and sparse regularization (SR). MICO-LDASR first corrects the bias fields of the input images by an energy minimization process and then selects the most discriminative image features using a combination of LDA and SR (LDASR) based on a supervised feature selection and learning. Two pairs of fused radar and optical data were used in this study. Features, such as non-negative matrix factorization and textural features, were extracted from the original and bias corrected images, and, following the formation of two different types of feature matrices, the matrices were optimized based on LDASR and utilized in the two learned and unlearned forms as the inputs to rotation forest and support vector machine classifiers. The results showed that classification accuracy is greatly improved when implementing MICO-LDASR on feature matrices of Sentinel and ALOS-fused data.

  19. Standardised criteria improve accuracy of ECG interpretation in competitive athletes: a randomised controlled trial.

    Science.gov (United States)

    Exeter, Daniel J; Elley, C Raina; Fulcher, Mark L; Lee, Arier C; Drezner, Jonathan A; Asif, Irfan M

    2014-08-01

    Screening to prevent sudden cardiac death remains a contentious topic in sport and exercise medicine. The aim of this study was to assess whether the use of a standardised criteria tool improves the accuracy of ECG interpretation by physicians screening athletes. Design: Randomised control trial. Study Population: General practitioners with an interest in sports medicine, sports physicians, sports medicine registrars and cardiologists from Australia and New Zealand were eligible to participate. Outcome Measures: Accuracy, sensitivity, specificity and false-positive rates of screening ECG interpretation of athletes. Intervention: A two-page standardised ECG criteria tool was provided to intervention participants. Control participants undertook 'usual' interpretation. 62 physicians, with a mean duration of practice of 16 years, were randomised to intervention and control. 10 baseline and 30 postrandomisation athlete ECGs were interpreted by the participants. Intervention participants were more likely to be correct: OR 1.72 (95% CI 1.31 to 2.27, pathletes can be improved by using a standardised ECG criteria tool. Use of the tool results in lower false-positive rates; this may have implications for screening recommendations. ACTRN12612000641897. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

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

    Directory of Open Access Journals (Sweden)

    Donghwan Yoon

    2016-06-01

    Full Text Available 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.

  1. Affine registration of three-dimensional point sets for improving the accuracy of eye position trackers

    Science.gov (United States)

    Kang, Donghoon; Kim, Jinwook; Kim, Sung-Kyu

    2017-04-01

    Existing methods for tracking three-dimensional (3-D) eye positions with a monocular color camera mostly rely on a generic 3-D face model and a certain face database. However, the performance of these methods is susceptible to the variations of head poses. For this reason, existing methods for estimating 3-D eye position from a single two-dimensional face image may yield erroneous results. To improve the accuracy of 3-D eye position trackers using a monocular camera, we present a compensation method as a postprocessing technique. We address the problem of determining an optimal registration function for fitting 3-D data consisting of the inaccurate estimates from the eye position tracker and their corresponding ground truths. To obtain the ground truths of 3-D eye positions, we propose two different systems by combining an optical motion capture system and checkerboards, which construct the form of the hand-eye and robot-world calibration. By solving a least-squares optimization problem, we can determine the optimal registration function in an affine form. Real experiments demonstrate that the proposed method can considerably improve the accuracy of 3-D eye position trackers using a single color camera.

  2. Dual-wavelength retinal images denoising algorithm for improving the accuracy of oxygen saturation calculation

    Science.gov (United States)

    Xian, Yong-Li; Dai, Yun; Gao, Chun-Ming; Du, Rui

    2017-01-01

    Noninvasive measurement of hemoglobin oxygen saturation (SO2) in retinal vessels is based on spectrophotometry and spectral absorption characteristics of tissue. Retinal images at 570 and 600 nm are simultaneously captured by dual-wavelength retinal oximetry based on fundus camera. SO2 is finally measured after vessel segmentation, image registration, and calculation of optical density ratio of two images. However, image noise can dramatically affect subsequent image processing and SO2 calculation accuracy. The aforementioned problem remains to be addressed. The purpose of this study was to improve image quality and SO2 calculation accuracy by noise analysis and denoising algorithm for dual-wavelength images. First, noise parameters were estimated by mixed Poisson-Gaussian (MPG) noise model. Second, an MPG denoising algorithm which we called variance stabilizing transform (VST) + dual-domain image denoising (DDID) was proposed based on VST and improved dual-domain filter. The results show that VST + DDID is able to effectively remove MPG noise and preserve image edge details. VST + DDID is better than VST + block-matching and three-dimensional filtering, especially in preserving low-contrast details. The following simulation and analysis indicate that MPG noise in the retinal images can lead to erroneously low measurement for SO2, and the denoised images can provide more accurate grayscale values for retinal oximetry.

  3. Integrated multi-ISE arrays with improved sensitivity, accuracy and precision

    Science.gov (United States)

    Wang, Chunling; Yuan, Hongyan; Duan, Zhijuan; Xiao, Dan

    2017-03-01

    Increasing use of ion-selective electrodes (ISEs) in the biological and environmental fields has generated demand for high-sensitivity ISEs. However, improving the sensitivities of ISEs remains a challenge because of the limit of the Nernstian slope (59.2/n mV). Here, we present a universal ion detection method using an electronic integrated multi-electrode system (EIMES) that bypasses the Nernstian slope limit of 59.2/n mV, thereby enabling substantial enhancement of the sensitivity of ISEs. The results reveal that the response slope is greatly increased from 57.2 to 1711.3 mV, 57.3 to 564.7 mV and 57.7 to 576.2 mV by electronic integrated 30 Cl- electrodes, 10 F- electrodes and 10 glass pH electrodes, respectively. Thus, a tiny change in the ion concentration can be monitored, and correspondingly, the accuracy and precision are substantially improved. The EIMES is suited for all types of potentiometric sensors and may pave the way for monitoring of various ions with high accuracy and precision because of its high sensitivity.

  4. Spatio-Temporal Error Sources Analysis and Accuracy Improvement in Landsat 8 Image Ground Displacement Measurements

    Directory of Open Access Journals (Sweden)

    Chao Ding

    2016-11-01

    Full Text Available Because of the advantages of low cost, large coverage and short revisit cycle, Landsat 8 images have been widely applied to monitor earth surface movements. However, there are few systematic studies considering the error source characteristics or the improvement of the deformation field accuracy obtained by Landsat 8 image. In this study, we utilize the 2013 Mw 7.7 Balochistan, Pakistan earthquake to analyze error spatio-temporal characteristics and elaborate how to mitigate error sources in the deformation field extracted from multi-temporal Landsat 8 images. We found that the stripe artifacts and the topographic shadowing artifacts are two major error components in the deformation field, which currently lack overall understanding and an effective mitigation strategy. For the stripe artifacts, we propose a small spatial baseline (<200 m method to avoid the stripe artifacts effect on the deformation field. We also propose a small radiometric baseline method to reduce the topographic shadowing artifacts and radiometric decorrelation noises. Those performances and accuracy evaluation show that these two methods are effective in improving the precision of deformation field. This study provides the possibility to detect subtle ground movement with higher precision caused by earthquake, melting glaciers, landslides, etc., with Landsat 8 images. It is also a good reference for error source analysis and corrections in deformation field extracted from other optical satellite images.

  5. Improving sub-grid scale accuracy of boundary features in regional finite-difference models

    Science.gov (United States)

    Panday, Sorab; Langevin, Christian D.

    2012-01-01

    As an alternative to grid refinement, the concept of a ghost node, which was developed for nested grid applications, has been extended towards improving sub-grid scale accuracy of flow to conduits, wells, rivers or other boundary features that interact with a finite-difference groundwater flow model. The formulation is presented for correcting the regular finite-difference groundwater flow equations for confined and unconfined cases, with or without Newton Raphson linearization of the nonlinearities, to include the Ghost Node Correction (GNC) for location displacement. The correction may be applied on the right-hand side vector for a symmetric finite-difference Picard implementation, or on the left-hand side matrix for an implicit but asymmetric implementation. The finite-difference matrix connectivity structure may be maintained for an implicit implementation by only selecting contributing nodes that are a part of the finite-difference connectivity. Proof of concept example problems are provided to demonstrate the improved accuracy that may be achieved through sub-grid scale corrections using the GNC schemes.

  6. Case studies on forecasting for innovative technologies: frequent revisions improve accuracy.

    Science.gov (United States)

    Lerner, Jeffrey C; Robertson, Diane C; Goldstein, Sara M

    2015-02-01

    Health technology forecasting is designed to provide reliable predictions about costs, utilization, diffusion, and other market realities before the technologies enter routine clinical use. In this article we address three questions central to forecasting's usefulness: Are early forecasts sufficiently accurate to help providers acquire the most promising technology and payers to set effective coverage policies? What variables contribute to inaccurate forecasts? How can forecasters manage the variables to improve accuracy? We analyzed forecasts published between 2007 and 2010 by the ECRI Institute on four technologies: single-room proton beam radiation therapy for various cancers; digital breast tomosynthesis imaging technology for breast cancer screening; transcatheter aortic valve replacement for serious heart valve disease; and minimally invasive robot-assisted surgery for various cancers. We then examined revised ECRI forecasts published in 2013 (digital breast tomosynthesis) and 2014 (the other three topics) to identify inaccuracies in the earlier forecasts and explore why they occurred. We found that five of twenty early predictions were inaccurate when compared with the updated forecasts. The inaccuracies pertained to two technologies that had more time-sensitive variables to consider. The case studies suggest that frequent revision of forecasts could improve accuracy, especially for complex technologies whose eventual use is governed by multiple interactive factors. Project HOPE—The People-to-People Health Foundation, Inc.

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

    Directory of Open Access Journals (Sweden)

    Changho Lee

    2013-03-01

    Full Text Available 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.

  8. Clustering and training set selection methods for improving the accuracy of quantitative laser induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Ryan B., E-mail: randerson@astro.cornell.edu [Cornell University Department of Astronomy, 406 Space Sciences Building, Ithaca, NY 14853 (United States); Bell, James F., E-mail: Jim.Bell@asu.edu [Arizona State University School of Earth and Space Exploration, Bldg.: INTDS-A, Room: 115B, Box 871404, Tempe, AZ 85287 (United States); Wiens, Roger C., E-mail: rwiens@lanl.gov [Los Alamos National Laboratory, P.O. Box 1663 MS J565, Los Alamos, NM 87545 (United States); Morris, Richard V., E-mail: richard.v.morris@nasa.gov [NASA Johnson Space Center, 2101 NASA Parkway, Houston, TX 77058 (United States); Clegg, Samuel M., E-mail: sclegg@lanl.gov [Los Alamos National Laboratory, P.O. Box 1663 MS J565, Los Alamos, NM 87545 (United States)

    2012-04-15

    We investigated five clustering and training set selection methods to improve the accuracy of quantitative chemical analysis of geologic samples by laser induced breakdown spectroscopy (LIBS) using partial least squares (PLS) regression. The LIBS spectra were previously acquired for 195 rock slabs and 31 pressed powder geostandards under 7 Torr CO{sub 2} at a stand-off distance of 7 m at 17 mJ per pulse to simulate the operational conditions of the ChemCam LIBS instrument on the Mars Science Laboratory Curiosity rover. The clustering and training set selection methods, which do not require prior knowledge of the chemical composition of the test-set samples, are based on grouping similar spectra and selecting appropriate training spectra for the partial least squares (PLS2) model. These methods were: (1) hierarchical clustering of the full set of training spectra and selection of a subset for use in training; (2) k-means clustering of all spectra and generation of PLS2 models based on the training samples within each cluster; (3) iterative use of PLS2 to predict sample composition and k-means clustering of the predicted compositions to subdivide the groups of spectra; (4) soft independent modeling of class analogy (SIMCA) classification of spectra, and generation of PLS2 models based on the training samples within each class; (5) use of Bayesian information criteria (BIC) to determine an optimal number of clusters and generation of PLS2 models based on the training samples within each cluster. The iterative method and the k-means method using 5 clusters showed the best performance, improving the absolute quadrature root mean squared error (RMSE) by {approx} 3 wt.%. The statistical significance of these improvements was {approx} 85%. Our results show that although clustering methods can modestly improve results, a large and diverse training set is the most reliable way to improve the accuracy of quantitative LIBS. In particular, additional sulfate standards and

  9. Toward Improved Force-Field Accuracy through Sensitivity Analysis of Host-Guest Binding Thermodynamics

    Science.gov (United States)

    Yin, Jian; Fenley, Andrew T.; Henriksen, Niel M.; Gilson, Michael K.

    2015-01-01

    Improving the capability of atomistic computer models to predict the thermodynamics of noncovalent binding is critical for successful structure-based drug design, and the accuracy of such calculations remains limited by non-optimal force field parameters. Ideally, one would incorporate protein-ligand affinity data into force field parametrization, but this would be inefficient and costly. We now demonstrate that sensitivity analysis can be used to efficiently tune Lennard-Jones parameters of aqueous host-guest systems for increasingly accurate calculations of binding enthalpy. These results highlight the promise of a comprehensive use of calorimetric host-guest binding data, along with existing validation data sets, to improve force field parameters for the simulation of noncovalent binding, with the ultimate goal of making protein-ligand modeling more accurate and hence speeding drug discovery. PMID:26181208

  10. Correlation between provider computer experience and accuracy of electronic anesthesia charting A pilot study and performance improvement project

    Science.gov (United States)

    2017-03-20

    Anesthesia recordkeeping: Accuracy of recall with computerized and manual entry recordkeeping. CORRELATION BETWEEN PROVIDER COMPUTER EXPERIENCE 39...Unexpected increased mortality after implementation of a CORRELATION BETWEEN PROVIDER COMPUTER EXPERIENCE 40 commercially sold computerized physician...Correlation between provider computer experience and accuracy of electronic anesthesia charting – A pilot study and performance improvement

  11. Improvement of the accuracy of continuous GPS/Acoustic measurement using a slackly moored buoy

    Science.gov (United States)

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

    2016-12-01

    For the real-time detection of seafloor crustal movement and tsunami associated with large earthquakes, it is necessary to monitor them continuously in their source regions. For this purpose, Tohoku University, JAMSTEC, and JAXA have co-developed a continuous GPS/Acoustic (GPS/A) measurement system using a moored buoy, and the third sea-trial is ongoing for a year in Kumano-nada, Nankai Trough. In this presentation, we report of the positioning accuracy of the continuous GPS/Acoustic measurement in the buoy system. We have adopted the array positioning technique developed by researchers at the Scripps Institute of Oceanography with some improvements. The advantage of this method is that errors in assumed sound velocity and array geometry (relative positions of individual seafloor transponders) little affect positioning results when measurements are conducted in the vicinity of the array center. However, the GPS/A measurement using a moored buoy is generally conducted under much worse condition than the conventional one using a research vessel. In our system, the mooring cable length was determined to be 1.5 times the water depth for safety reasons against strong current. Therefore, the buoy is drifting within a relatively wide area by the wind and the current, and measurements are randomly performed at various points within the area. These features can lead to significant systematic errors in the array positioning, because the effect of errors in pre-defined array geometry increases as the observation point goes farther from the array center. At the moments, the positioning accuracy of GPS/A measurement using a moored buoy is estimated as 0.6/0.7 m, for the EW/NS components, respectively, from the data obtained during the third sea-trial. It is considered that errors in the assumed array geometry result in considerable errors in the array positioning. Therefore, it is necessary to determine the array geometry more precisely in order to improve the accuracy of GPS

  12. Iterative metal artifact reduction improves dose calculation accuracy. Phantom study with dental implants

    Energy Technology Data Exchange (ETDEWEB)

    Maerz, Manuel; Mittermair, Pia; Koelbl, Oliver; Dobler, Barbara [Regensburg University Medical Center, Department of Radiotherapy, Regensburg (Germany); Krauss, Andreas [Siemens Healthcare GmbH, Forchheim (Germany)

    2016-06-15

    Metallic dental implants cause severe streaking artifacts in computed tomography (CT) data, which affect the accuracy of dose calculations in radiation therapy. The aim of this study was to investigate the benefit of the metal artifact reduction algorithm iterative metal artifact reduction (iMAR) in terms of correct representation of Hounsfield units (HU) and dose calculation accuracy. Heterogeneous phantoms consisting of different types of tissue equivalent material surrounding metallic dental implants were designed. Artifact-containing CT data of the phantoms were corrected using iMAR. Corrected and uncorrected CT data were compared to synthetic CT data to evaluate accuracy of HU reproduction. Intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans were calculated in Oncentra v4.3 on corrected and uncorrected CT data and compared to Gafchromic trademark EBT3 films to assess accuracy of dose calculation. The use of iMAR increased the accuracy of HU reproduction. The average deviation of HU decreased from 1006 HU to 408 HU in areas including metal and from 283 HU to 33 HU in tissue areas excluding metal. Dose calculation accuracy could be significantly improved for all phantoms and plans: The mean passing rate for gamma evaluation with 3 % dose tolerance and 3 mm distance to agreement increased from 90.6 % to 96.2 % if artifacts were corrected by iMAR. The application of iMAR allows metal artifacts to be removed to a great extent which leads to a significant increase in dose calculation accuracy. (orig.) [German] Metallische Implantate verursachen streifenfoermige Artefakte in CT-Bildern, welche die Dosisberechnung beeinflussen. In dieser Studie soll der Nutzen des iterativen Metall-Artefakt-Reduktions-Algorithmus iMAR hinsichtlich der Wiedergabetreue von Hounsfield-Werten (HU) und der Genauigkeit von Dosisberechnungen untersucht werden. Es wurden heterogene Phantome aus verschiedenen Arten gewebeaequivalenten Materials mit

  13. Borderline Ovarian Tumors and Diagnostic Dilemma of Intraoperative Diagnosis: Could Preoperative He4 Assay and ROMA Score Assessment Increase the Frozen Section Accuracy? A Multicenter Case-Control Study

    Directory of Open Access Journals (Sweden)

    Salvatore Gizzo

    2014-01-01

    Full Text Available The aim of our study was to assess the value of a preoperative He4-serum-assay and ROMA-score assessment in improving the accuracy of frozen section histology in the diagnosis of borderline ovarian tumors (BOT. 113 women presenting with a unilateral ovarian mass diagnosed as serous/mucinous BOT at frozen-section-histology (FS and/or confirmed on final pathology were recruited. Pathologists were informed of the results of preoperative clinical/instrumental assessment of all patients. For Group_A patients, additional information regarding He4, CA125, and ROMA score was available (in Group_B only CA125 was known. The comparison between Group A and Group B in terms of FS accuracy, demonstrated a consensual diagnosis in 62.8% versus 58.6% (P: n.s., underdiagnosis in 25.6% versus 41.4% (P<0.05, and overdiagnosis in 11.6% versus 0% (P<0.01. Low FS diagnostic accuracy was associated with menopausal status (OR: 2.13, laparoscopic approach (OR: 2.18, mucinous histotype (OR: 2.23, low grading (OR: 1.30, and FIGO stage I (OR: 2.53. Ultrasound detection of papillae (OR: 0.29, septa (OR: 0.39, atypical vascularization (OR: 0.34, serum He4 assay (OR: 0.39, and ROMA score assessment (OR: 0.44 decreased the probability of underdiagnosis. A combined preoperative assessment through serum markers and ultrasonographic features may potentially reduce the risk of underdiagnosis of BOTs on FS while likely increasing the concomitant incidence of false-positive events.

  14. Spatially distributed modeling of soil organic carbon across China with improved accuracy

    Science.gov (United States)

    Li, Qi-quan; Zhang, Hao; Jiang, Xin-ye; Luo, Youlin; Wang, Chang-quan; Yue, Tian-xiang; Li, Bing; Gao, Xue-song

    2017-06-01

    There is a need for more detailed spatial information on soil organic carbon (SOC) for the accurate estimation of SOC stock and earth system models. As it is effective to use environmental factors as auxiliary variables to improve the prediction accuracy of spatially distributed modeling, a combined method (HASM_EF) was developed to predict the spatial pattern of SOC across China using high accuracy surface modeling (HASM), artificial neural network (ANN), and principal component analysis (PCA) to introduce land uses, soil types, climatic factors, topographic attributes, and vegetation cover as predictors. The performance of HASM_EF was compared with ordinary kriging (OK), OK, and HASM combined, respectively, with land uses and soil types (OK_LS and HASM_LS), and regression kriging combined with land uses and soil types (RK_LS). Results showed that HASM_EF obtained the lowest prediction errors and the ratio of performance to deviation (RPD) presented the relative improvements of 89.91%, 63.77%, 55.86%, and 42.14%, respectively, compared to the other four methods. Furthermore, HASM_EF generated more details and more realistic spatial information on SOC. The improved performance of HASM_EF can be attributed to the introduction of more environmental factors, to explicit consideration of the multicollinearity of selected factors and the spatial nonstationarity and nonlinearity of relationships between SOC and selected factors, and to the performance of HASM and ANN. This method may play a useful tool in providing more precise spatial information on soil parameters for global modeling across large areas.

  15. Improving Precision, Maintaining Accuracy, and Reducing Acquisition Time for Trace Elements in EPMA

    Science.gov (United States)

    Donovan, J.; Singer, J.; Armstrong, J. T.

    2016-12-01

    Trace element precision in electron probe micro analysis (EPMA) is limited by intrinsic random variation in the x-ray continuum. Traditionally we characterize background intensity by measuring on either side of the emission line and interpolating the intensity underneath the peak to obtain the net intensity. Alternatively, we can measure the background intensity at the on-peak spectrometer position using a number of standard materials that do not contain the element of interest. This so-called mean atomic number (MAN) background calibration (Donovan, et al., 2016) uses a set of standard measurements, covering an appropriate range of average atomic number, to iteratively estimate the continuum intensity for the unknown composition (and hence average atomic number). We will demonstrate that, at least for materials with a relatively simple matrix such as SiO2, TiO2, ZrSiO4, etc. where one may obtain a matrix matched standard for use in the so called "blank correction", we can obtain trace element accuracy comparable to traditional off-peak methods, and with improved precision, in about half the time. Donovan, Singer and Armstrong, A New EPMA Method for Fast Trace Element Analysis in Simple Matrices ", American Mineralogist, v101, p1839-1853, 2016 Figure 1. Uranium concentration line profiles from quantitative x-ray maps (20 keV, 100 nA, 5 um beam size and 4000 msec per pixel), for both off-peak and MAN background methods without (a), and with (b), the blank correction applied. We see precision significantly improved compared with traditional off-peak measurements while, in this case, the blank correction provides a small but discernable improvement in accuracy.

  16. Improvements in ECG accuracy for diagnosis of left ventricular hypertrophy in obesity.

    Science.gov (United States)

    Rider, Oliver J; Ntusi, Ntobeko; Bull, Sacha C; Nethononda, Richard; Ferreira, Vanessa; Holloway, Cameron J; Holdsworth, David; Mahmod, Masliza; Rayner, Jennifer J; Banerjee, Rajarshi; Myerson, Saul; Watkins, Hugh; Neubauer, Stefan

    2016-10-01

    The electrocardiogram (ECG) is the most commonly used tool to screen for left ventricular hypertrophy (LVH), and yet current diagnostic criteria are insensitive in modern increasingly overweight society. We propose a simple adjustment to improve diagnostic accuracy in different body weights and improve the sensitivity of this universally available technique. Overall, 1295 participants were included-821 with a wide range of body mass index (BMI 17.1-53.3 kg/m(2)) initially underwent cardiac magnetic resonance evaluation of anatomical left ventricular (LV) axis, LV mass and 12-lead surface ECG in order to generate an adjustment factor applied to the Sokolow-Lyon criteria. This factor was then validated in a second cohort (n=520, BMI 15.9-63.2 kg/m(2)). When matched for LV mass, the combination of leftward anatomical axis deviation and increased BMI resulted in a reduction of the Sokolow-Lyon index, by 4 mm in overweight and 8 mm in obesity. After adjusting for this in the initial cohort, the sensitivity of the Sokolow-Lyon index increased (overweight: 12.8% to 30.8%, obese: 3.1% to 27.2%) approaching that seen in normal weight (37.8%). Similar results were achieved in the validation cohort (specificity increased in overweight: 8.3% to 39.1%, obese: 9.4% to 25.0%) again approaching normal weight (39.0%). Importantly, specificity remained excellent (>93.1%). Adjusting the Sokolow-Lyon index for BMI (overweight +4 mm, obesity +8 mm) improves the diagnostic accuracy for detecting LVH. As the ECG, worldwide, remains the most widely used screening tool for LVH, implementing these findings should translate into significant clinical benefit. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  17. Knee joint secondary motion accuracy improved by quaternion-based optimizer with bony landmark constraints.

    Science.gov (United States)

    Wang, Hongsheng; Zheng, Naiqaun Nigel

    2010-12-01

    Skin marker-based motion analysis has been widely used in biomechanical studies and clinical applications. Unfortunately, the accuracy of knee joint secondary motions is largely limited by the nonrigidity nature of human body segments. Numerous studies have investigated the characteristics of soft tissue movement. Utilizing these characteristics, we may improve the accuracy of knee joint motion measurement. An optimizer was developed by incorporating the soft tissue movement patterns at special bony landmarks into constraint functions. Bony landmark constraints were assigned to the skin markers at femur epicondyles, tibial plateau edges, and tibial tuberosity in a motion analysis algorithm by limiting their allowed position space relative to the underlying bone. The rotation matrix was represented by quaternion, and the constrained optimization problem was solved by Fletcher's version of the Levenberg-Marquardt optimization technique. The algorithm was validated by using motion data from both skin-based markers and bone-mounted markers attached to fresh cadavers. By comparing the results with the ground truth bone motion generated from the bone-mounted markers, the new algorithm had a significantly higher accuracy (root-mean-square (RMS) error: 0.7 ± 0.1 deg in axial rotation and 0.4 ± 0.1 deg in varus-valgus) in estimating the knee joint secondary rotations than algorithms without bony landmark constraints (RMS error: 1.7 ± 0.4 deg in axial rotation and 0.7 ± 0.1 deg in varus-valgus). Also, it predicts a more accurate medial-lateral translation (RMS error: 0.4 ± 0.1 mm) than the conventional techniques (RMS error: 1.2 ± 0.2 mm). The new algorithm, using bony landmark constrains, estimates more accurate secondary rotations and medial-lateral translation of the underlying bone.

  18. Improving the accuracy of Møller-Plesset perturbation theory with neural networks

    Science.gov (United States)

    McGibbon, Robert T.; Taube, Andrew G.; Donchev, Alexander G.; Siva, Karthik; Hernández, Felipe; Hargus, Cory; Law, Ka-Hei; Klepeis, John L.; Shaw, David E.

    2017-10-01

    Noncovalent interactions are of fundamental importance across the disciplines of chemistry, materials science, and biology. Quantum chemical calculations on noncovalently bound complexes, which allow for the quantification of properties such as binding energies and geometries, play an essential role in advancing our understanding of, and building models for, a vast array of complex processes involving molecular association or self-assembly. Because of its relatively modest computational cost, second-order Møller-Plesset perturbation (MP2) theory is one of the most widely used methods in quantum chemistry for studying noncovalent interactions. MP2 is, however, plagued by serious errors due to its incomplete treatment of electron correlation, especially when modeling van der Waals interactions and π-stacked complexes. Here we present spin-network-scaled MP2 (SNS-MP2), a new semi-empirical MP2-based method for dimer interaction-energy calculations. To correct for errors in MP2, SNS-MP2 uses quantum chemical features of the complex under study in conjunction with a neural network to reweight terms appearing in the total MP2 interaction energy. The method has been trained on a new data set consisting of over 200 000 complete basis set (CBS)-extrapolated coupled-cluster interaction energies, which are considered the gold standard for chemical accuracy. SNS-MP2 predicts gold-standard binding energies of unseen test compounds with a mean absolute error of 0.04 kcal mol-1 (root-mean-square error 0.09 kcal mol-1), a 6- to 7-fold improvement over MP2. To the best of our knowledge, its accuracy exceeds that of all extant density functional theory- and wavefunction-based methods of similar computational cost, and is very close to the intrinsic accuracy of our benchmark coupled-cluster methodology itself. Furthermore, SNS-MP2 provides reliable per-conformation confidence intervals on the predicted interaction energies, a feature not available from any alternative method.

  19. Diagnostic accuracy of fecal calprotectin assay in distinguishing organic causes of chronic diarrhea from irritable bowel syndrome: a prospective study in adults and children.

    Science.gov (United States)

    Carroccio, Antonio; Iacono, Giuseppe; Cottone, Mario; Di Prima, Lidia; Cartabellotta, Fabio; Cavataio, Francesca; Scalici, Calogero; Montalto, Giuseppe; Di Fede, Gaetana; Rini, GiovamBattista; Notarbartolo, Alberto; Averna, Maurizio R

    2003-06-01

    Fecal calprotectin (FC) has been proposed as a marker of inflammatory bowel disease (IBD), but few studies have evaluated its usefulness in patients with chronic diarrhea of various causes. We evaluated the diagnostic accuracy of a FC assay in identifying "organic" causes of chronic diarrhea in consecutive adults and children. We consecutively enrolled 70 adult patients (30 males, 40 females; median age, 35 years) and 50 children (20 males, 30 females; median age, 3.5 years) with chronic diarrhea of unknown origin. All patients underwent a complete work-up to identify the causes of chronic diarrhea. FC was measured by ELISA. In adult patients, FC showed 64% sensitivity and 80% specificity with 70% positive and 74% negative predictive values for organic causes. False-positive results (8 of 40 cases) were associated with the use of aspirin (3 cases) or nonsteroidal antiinflammatory drugs (1 case) and with the presence of concomitant liver cirrhosis (3 cases). False-negative results mainly included patients suffering from celiac disease (5 cases). Patients with IBD (9 cases) were identified with 100% sensitivity and 95% specificity. In pediatric patients, sensitivity was 70%, specificity was 93%, and positive and negative predictive values were 96% and 56%. False-negative results (11 of 35 cases) were associated mainly with celiac disease (6 cases) or intestinal giardiasis (2 cases). FC assay is an accurate marker of IBD in both children and adult patients. In adults, false negatives occur (e.g., in celiac disease) and false-positive results are seen in cirrhosis or users of nonsteroidal antiinflammatory drugs. Diagnostic accuracy is higher in children.

  20. Improved accuracy in quantitative laser-induced breakdown spectroscopy using sub-models

    Science.gov (United States)

    Anderson, Ryan B.; Clegg, Samuel M.; Frydenvang, Jens; Wiens, Roger C.; McLennan, Scott; Morris, Richard V.; Ehlmann, Bethany; Dyar, M. Darby

    2017-03-01

    Accurate quantitative analysis of diverse geologic materials is one of the primary challenges faced by the laser-induced breakdown spectroscopy (LIBS)-based ChemCam instrument on the Mars Science Laboratory (MSL) rover. The SuperCam instrument on the Mars 2020 rover, as well as other LIBS instruments developed for geochemical analysis on Earth or other planets, will face the same challenge. Consequently, part of the ChemCam science team has focused on the development of improved multivariate analysis calibrations methods. Developing a single regression model capable of accurately determining the composition of very different target materials is difficult because the response of an element's emission lines in LIBS spectra can vary with the concentration of other elements. We demonstrate a conceptually simple "sub-model" method for improving the accuracy of quantitative LIBS analysis of diverse target materials. The method is based on training several regression models on sets of targets with limited composition ranges and then "blending" these "sub-models" into a single final result. Tests of the sub-model method show improvement in test set root mean squared error of prediction (RMSEP) for almost all cases. The sub-model method, using partial least squares (PLS) regression, is being used as part of the current ChemCam quantitative calibration, but the sub-model method is applicable to any multivariate regression method and may yield similar improvements.

  1. Improved accuracy in quantitative laser-induced breakdown spectroscopy using sub-models

    Science.gov (United States)

    Anderson, Ryan; Clegg, Samuel M.; Frydenvang, Jens; Wiens, Roger C.; McLennan, Scott M.; Morris, Richard V.; Ehlmann, Bethany L.; Dyar, M. Darby

    2017-01-01

    Accurate quantitative analysis of diverse geologic materials is one of the primary challenges faced by the Laser-Induced Breakdown Spectroscopy (LIBS)-based ChemCam instrument on the Mars Science Laboratory (MSL) rover. The SuperCam instrument on the Mars 2020 rover, as well as other LIBS instruments developed for geochemical analysis on Earth or other planets, will face the same challenge. Consequently, part of the ChemCam science team has focused on the development of improved multivariate analysis calibrations methods. Developing a single regression model capable of accurately determining the composition of very different target materials is difficult because the response of an element’s emission lines in LIBS spectra can vary with the concentration of other elements. We demonstrate a conceptually simple “sub-model” method for improving the accuracy of quantitative LIBS analysis of diverse target materials. The method is based on training several regression models on sets of targets with limited composition ranges and then “blending” these “sub-models” into a single final result. Tests of the sub-model method show improvement in test set root mean squared error of prediction (RMSEP) for almost all cases. The sub-model method, using partial least squares regression (PLS), is being used as part of the current ChemCam quantitative calibration, but the sub-model method is applicable to any multivariate regression method and may yield similar improvements.

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

    Science.gov (United States)

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

    2016-04-07

    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. Copyright © 2016 Ramstein et al.

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

    Directory of Open Access Journals (Sweden)

    Guillaume P. Ramstein

    2016-04-01

    Full Text Available 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.

  4. Attitude Modeling Using Kalman Filter Approach for Improving the Geometric Accuracy of Cartosat-1 Data Products

    Directory of Open Access Journals (Sweden)

    Nita H. SHAH

    2010-07-01

    Full Text Available This paper deals with the rigorous photogrammetric solution to model the uncertainty in the orientation parameters of Indian Remote Sensing Satellite IRS-P5 (Cartosat-1. Cartosat-1 is a three axis stabilized spacecraft launched into polar sun-synchronous circular orbit at an altitude of 618 km. The satellite has two panchromatic (PAN cameras with nominal resolution of ~2.5 m. The camera looking ahead is called FORE mounted with +26 deg angle and the other looking near nadir is called AFT mounted with -5 deg, in along track direction. Data Product Generation Software (DPGS system uses the rigorous photogrammetric Collinearity model in order to utilize the full system information, together with payload geometry & control points, for estimating the uncertainty in attitude parameters. The initial orbit, attitude knowledge is obtained from GPS bound orbit measurement, star tracker and gyros. The variations in satellite attitude with time are modelled using simple linear polynomial model. Also, based on this model, Kalman filter approach is studied and applied to improve the uncertainty in the orientation of spacecraft with high quality ground control points (GCPs. The sequential estimator (Kalman filter is used in an iterative process which corrects the parameters at each time of observation rather than at epoch time. Results are presented for three stereo data sets. The accuracy of model depends on the accuracy of the control points.

  5. A robust data scaling algorithm to improve classification accuracies in biomedical data.

    Science.gov (United States)

    Cao, Xi Hang; Stojkovic, Ivan; Obradovic, Zoran

    2016-09-09

    Machine learning models have been adapted in biomedical research and practice for knowledge discovery and decision support. While mainstream biomedical informatics research focuses on developing more accurate models, the importance of data preprocessing draws less attention. We propose the Generalized Logistic (GL) algorithm that scales data uniformly to an appropriate interval by learning a generalized logistic function to fit the empirical cumulative distribution function of the data. The GL algorithm is simple yet effective; it is intrinsically robust to outliers, so it is particularly suitable for diagnostic/classification models in clinical/medical applications where the number of samples is usually small; it scales the data in a nonlinear fashion, which leads to potential improvement in accuracy. To evaluate the effectiveness of the proposed algorithm, we conducted experiments on 16 binary classification tasks with different variable types and cover a wide range of applications. The resultant performance in terms of area under the receiver operation characteristic curve (AUROC) and percentage of correct classification showed that models learned using data scaled by the GL algorithm outperform the ones using data scaled by the Min-max and the Z-score algorithm, which are the most commonly used data scaling algorithms. The proposed GL algorithm is simple and effective. It is robust to outliers, so no additional denoising or outlier detection step is needed in data preprocessing. Empirical results also show models learned from data scaled by the GL algorithm have higher accuracy compared to the commonly used data scaling algorithms.

  6. Does an Adolescent’s Accuracy of Recall Improve with a Second 24-h Dietary Recall?

    Directory of Open Access Journals (Sweden)

    Deborah A. Kerr

    2015-05-01

    Full Text Available The multiple-pass 24-h dietary recall is used in most national dietary surveys. Our purpose was to assess if adolescents’ accuracy of recall improved when a 5-step multiple-pass 24-h recall was repeated. Participants (n = 24, were Chinese-American youths aged between 11 and 15 years and lived in a supervised environment as part of a metabolic feeding study. The 24-h recalls were conducted on two occasions during the first five days of the study. The four steps (quick list; forgotten foods; time and eating occasion; detailed description of the food/beverage of the 24-h recall were assessed for matches by category. Differences were observed in the matching for the time and occasion step (p < 0.01, detailed description (p < 0.05 and portion size matching (p < 0.05. Omission rates were higher for the second recall (p < 0.05 quick list; p < 0.01 forgotten foods. The adolescents over-estimated energy intake on the first (11.3% ± 22.5%; p < 0.05 and second recall (10.1% ± 20.8% compared with the known food and beverage items. These results suggest that the adolescents’ accuracy to recall food items declined with a second 24-h recall when repeated over two non-consecutive days.

  7. Error-corrected AFM: a simple and broadly applicable approach for substantially improving AFM image accuracy.

    Science.gov (United States)

    Bosse, James L; Huey, Bryan D

    2014-04-18

    Atomic force microscopy (AFM) has become an indispensable tool for imaging the topography and properties of surfaces at the nanoscale. A ubiquitous problem, however, is that optimal accuracy demands smooth surfaces, slow scanning, and expert users, contrary to many AFM applications and practical use patterns. Accordingly, a simple correction to AFM topographic images is implemented, incorporating error signals such as deflection and/or amplitude data that have long been available but quantitatively underexploited. This is demonstrated to substantially improve both height and lateral accuracy for expert users, with a corresponding 3-5 fold decrease in image error. Common image artifacts due to inexperienced AFM use, generally poorly scanned surfaces, or high speed images acquired in as fast as 7 s, are also shown to be effectively rectified, returning results equivalent to standard 'expert-user' images. This concept is proven for contact mode AFM, AC-mode, and high speed imaging, as well as property mapping such as phase contrast, with obvious extensions to many specialized AFM variations as well. Conveniently, as this correction procedure is based on either real time or post-processing, it is easily employed for future as well as legacy AFM systems and data. Such error-corrected AFM therefore offers a simple, broadly applicable approach for more accurate, more efficient, and more user-friendly implementation of AFM for nanoscale topography and property mapping.

  8. Accuracy Improvement of Discharge Measurement with Modification of Distance Made Good Heading

    Directory of Open Access Journals (Sweden)

    Jongkook Lee

    2016-01-01

    Full Text Available Remote control boats equipped with an Acoustic Doppler Current Profiler (ADCP are widely accepted and have been welcomed by many hydrologists for water discharge, velocity profile, and bathymetry measurements. The advantages of this technique include high productivity, fast measurements, operator safety, and high accuracy. However, there are concerns about controlling and operating a remote boat to achieve measurement goals, especially during extreme events such as floods. When performing river discharge measurements, the main error source stems from the boat path. Due to the rapid flow in a flood condition, the boat path is not regular and this can cause errors in discharge measurements. Therefore, improvement of discharge measurements requires modification of boat path. As a result, the measurement errors in flood flow conditions are 12.3–21.8% before the modification of boat path, but 1.2–3.7% after the DMG modification of boat path. And it is considered that the modified discharges are very close to the observed discharge in the flood flow conditions. In this study, through the distance made good (DMG modification of the boat path, a comprehensive discharge measurement with high accuracy can be achieved.

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

    Directory of Open Access Journals (Sweden)

    José Neuman de Souza

    2011-10-01

    Full Text Available 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.

  10. Improving the accuracy of skin elasticity measurement by using Q-parameters in Cutometer.

    Science.gov (United States)

    Qu, Di; Seehra, G Paul

    2016-01-01

    The skin elasticity parameters (Ue, Uv, Uf, Ur, Ua, and R0 through R9) in the Cutometer are widely used for in vivo measurement of skin elasticity. Their accuracy, however, is impaired by the inadequacy of the definition of a key parameter, the time point of 0.1 s, which separates the elastic and viscoelastic responses of human skin. This study shows why an inflection point (t(IP)) should be calculated from each individual response curve to define skin elasticity, and how the Q-parameters are defined in the Cutometer. By analyzing the strain versus time curves of some pure elastic standards and of a population of 746 human volunteers, a method of determining the t(IP) from each mode 1 response curve was established. The results showed a wide distribution of this parameter ranging from 0.11 to 0.19 s, demonstrating that the current single-valued empirical parameter of 0.1 s was not adequate to represent this property of skin. A set of area-based skin viscoelastic parameters were also defined. The biological elasticity thus obtained correlated well with the study volunteers' chronological age which was statistically significant. We conclude that the Q-parameters are more accurate than the U and R parameters and should be used to improve measurement accuracy of human skin elasticity.

  11. Improved Variant Calling Accuracy by Merging Replicates in Whole-Exome Sequencing Studies

    Directory of Open Access Journals (Sweden)

    Yanfeng Zhang

    2014-01-01

    Full Text Available In large scale population-based whole-exome sequencing (WES studies, there are some samples occasionally sequenced two or more times due to a variety of reasons. To investigate how to efficiently utilize these duplicated sequencing data, we conducted comprehensive evaluation of variant calling strategies. 92 samples subjected to WES twice were selected from a large population study. These 92 duplicated samples were divided into two groups: group H consisting of the higher sequencing depth for each subject and group L consisting of the lower depth for each subject. The merged samples for each subject were put in a third group M. Using the GATK multisample toolkit, we compared variant calling accuracy among three strategies. Hierarchical clustering analysis indicated that the two replicates for each subject showed high homogeneity. The comparative analyses on the basis of heterozygous-homozygous ratio (Hete/Homo, transition-transversion ratio (Ti/Tv, and overlapping rate with the 1000 Genomes Project consistently showed that the data quality of the SNPs detected from the M group was more accurate than that of SNPs detected from the H and L groups. These results suggested that merging homogeneous duplicated exomes instead of using one of them could improve variant calling accuracy.

  12. Improving accuracy of protein-protein interaction prediction by considering the converse problem for sequence representation

    Directory of Open Access Journals (Sweden)

    Wang Yong

    2011-10-01

    Full Text Available Abstract Background With the development of genome-sequencing technologies, protein sequences are readily obtained by translating the measured mRNAs. Therefore predicting protein-protein interactions from the sequences is of great demand. The reason lies in the fact that identifying protein-protein interactions is becoming a bottleneck for eventually understanding the functions of proteins, especially for those organisms barely characterized. Although a few methods have been proposed, the converse problem, if the features used extract sufficient and unbiased information from protein sequences, is almost untouched. Results In this study, we interrogate this problem theoretically by an optimization scheme. Motivated by the theoretical investigation, we find novel encoding methods for both protein sequences and protein pairs. Our new methods exploit sufficiently the information of protein sequences and reduce artificial bias and computational cost. Thus, it significantly outperforms the available methods regarding sensitivity, specificity, precision, and recall with cross-validation evaluation and reaches ~80% and ~90% accuracy in Escherichia coli and Saccharomyces cerevisiae respectively. Our findings here hold important implication for other sequence-based prediction tasks because representation of biological sequence is always the first step in computational biology. Conclusions By considering the converse problem, we propose new representation methods for both protein sequences and protein pairs. The results show that our method significantly improves the accuracy of protein-protein interaction predictions.

  13. Improving prediction accuracy for WSN data reduction by applying multivariate spatio-temporal correlation.

    Science.gov (United States)

    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.

  14. Error-corrected AFM: a simple and broadly applicable approach for substantially improving AFM image accuracy

    Science.gov (United States)

    Bosse, James L.; Huey, Bryan D.

    2014-04-01

    Atomic force microscopy (AFM) has become an indispensable tool for imaging the topography and properties of surfaces at the nanoscale. A ubiquitous problem, however, is that optimal accuracy demands smooth surfaces, slow scanning, and expert users, contrary to many AFM applications and practical use patterns. Accordingly, a simple correction to AFM topographic images is implemented, incorporating error signals such as deflection and/or amplitude data that have long been available but quantitatively underexploited. This is demonstrated to substantially improve both height and lateral accuracy for expert users, with a corresponding 3-5 fold decrease in image error. Common image artifacts due to inexperienced AFM use, generally poorly scanned surfaces, or high speed images acquired in as fast as 7 s, are also shown to be effectively rectified, returning results equivalent to standard ‘expert-user’ images. This concept is proven for contact mode AFM, AC-mode, and high speed imaging, as well as property mapping such as phase contrast, with obvious extensions to many specialized AFM variations as well. Conveniently, as this correction procedure is based on either real time or post-processing, it is easily employed for future as well as legacy AFM systems and data. Such error-corrected AFM therefore offers a simple, broadly applicable approach for more accurate, more efficient, and more user-friendly implementation of AFM for nanoscale topography and property mapping.

  15. Diagnostic accuracy of two multiplex real-time polymerase chain reaction assays for the diagnosis of meningitis in children in a resource-limited setting.

    Directory of Open Access Journals (Sweden)

    Jermaine Khumalo

    Full Text Available Accurate etiological diagnosis of meningitis is important, but difficult in resource-limited settings due to prior administration of antibiotics and lack of viral diagnostics. We aimed to develop and validate 2 real-time multiplex PCR (RT-PCR assays for the detection of common causes of community-acquired bacterial and viral meningitis in South African children.We developed 2 multiplex RT- PCRs for detection of S. pneumoniae, N. meningitidis, H. influenzae, enteroviruses, mumps virus and herpes simplex virus. We tested residual CSF samples from children presenting to a local paediatric hospital over a one-year period, whose CSF showed an abnormal cell count. Results were compared with routine diagnostic tests and the final discharge diagnosis. We calculated accuracy of the bacterial RT-PCR assay compared to CSF culture and using World Health Organisation definitions of laboratory-confirmed bacterial meningitis.From 292 samples, bacterial DNA was detected in 12 (4.1% and viral nucleic acids in 94 (32%. Compared to CSF culture, the sensitivity and specificity of the bacterial RT-PCR was 100% and 97.2% with complete agreement in organism identification. None of the cases positive by viral RT-PCR had a bacterial cause confirmed on CSF culture. Only 9/90 (10% of patients diagnosed clinically as bacterial meningitis or partially treated bacterial meningitis tested positive with the bacterial RT-PCR.In this population the use of 2 multiplex RT-PCRs targeting 6 common pathogens gave promising results. If introduced into routine diagnostic testing, these multiplex RT-PCR assays would supplement other diagnostic tests, and have the potential to limit unnecessary antibiotic therapy and hospitalisation.

  16. Diagnostic accuracy of two multiplex real-time polymerase chain reaction assays for the diagnosis of meningitis in children in a resource-limited setting

    Science.gov (United States)

    Khumalo, Jermaine; Nicol, Mark; Hardie, Diana; Muloiwa, Rudzani; Mteshana, Phindile

    2017-01-01

    Introduction Accurate etiological diagnosis of meningitis is important, but difficult in resource-limited settings due to prior administration of antibiotics and lack of viral diagnostics. We aimed to develop and validate 2 real-time multiplex PCR (RT-PCR) assays for the detection of common causes of community-acquired bacterial and viral meningitis in South African children. Methods We developed 2 multiplex RT- PCRs for detection of S. pneumoniae, N. meningitidis, H. influenzae, enteroviruses, mumps virus and herpes simplex virus. We tested residual CSF samples from children presenting to a local paediatric hospital over a one-year period, whose CSF showed an abnormal cell count. Results were compared with routine diagnostic tests and the final discharge diagnosis. We calculated accuracy of the bacterial RT-PCR assay compared to CSF culture and using World Health Organisation definitions of laboratory-confirmed bacterial meningitis. Results From 292 samples, bacterial DNA was detected in 12 (4.1%) and viral nucleic acids in 94 (32%). Compared to CSF culture, the sensitivity and specificity of the bacterial RT-PCR was 100% and 97.2% with complete agreement in organism identification. None of the cases positive by viral RT-PCR had a bacterial cause confirmed on CSF culture. Only 9/90 (10%) of patients diagnosed clinically as bacterial meningitis or partially treated bacterial meningitis tested positive with the bacterial RT-PCR. Discussion In this population the use of 2 multiplex RT-PCRs targeting 6 common pathogens gave promising results. If introduced into routine diagnostic testing, these multiplex RT-PCR assays would supplement other diagnostic tests, and have the potential to limit unnecessary antibiotic therapy and hospitalisation. PMID:28346504

  17. Diagnostic accuracy of two multiplex real-time polymerase chain reaction assays for the diagnosis of meningitis in children in a resource-limited setting.

    Science.gov (United States)

    Khumalo, Jermaine; Nicol, Mark; Hardie, Diana; Muloiwa, Rudzani; Mteshana, Phindile; Bamford, Colleen

    2017-01-01

    Accurate etiological diagnosis of meningitis is important, but difficult in resource-limited settings due to prior administration of antibiotics and lack of viral diagnostics. We aimed to develop and validate 2 real-time multiplex PCR (RT-PCR) assays for the detection of common causes of community-acquired bacterial and viral meningitis in South African children. We developed 2 multiplex RT- PCRs for detection of S. pneumoniae, N. meningitidis, H. influenzae, enteroviruses, mumps virus and herpes simplex virus. We tested residual CSF samples from children presenting to a local paediatric hospital over a one-year period, whose CSF showed an abnormal cell count. Results were compared with routine diagnostic tests and the final discharge diagnosis. We calculated accuracy of the bacterial RT-PCR assay compared to CSF culture and using World Health Organisation definitions of laboratory-confirmed bacterial meningitis. From 292 samples, bacterial DNA was detected in 12 (4.1%) and viral nucleic acids in 94 (32%). Compared to CSF culture, the sensitivity and specificity of the bacterial RT-PCR was 100% and 97.2% with complete agreement in organism identification. None of the cases positive by viral RT-PCR had a bacterial cause confirmed on CSF culture. Only 9/90 (10%) of patients diagnosed clinically as bacterial meningitis or partially treated bacterial meningitis tested positive with the bacterial RT-PCR. In this population the use of 2 multiplex RT-PCRs targeting 6 common pathogens gave promising results. If introduced into routine diagnostic testing, these multiplex RT-PCR assays would supplement other diagnostic tests, and have the potential to limit unnecessary antibiotic therapy and hospitalisation.

  18. Improvement of Position Estimation Accuracy in IPMSM Sensorless Drives with On-Line Parameter Identification

    Science.gov (United States)

    Inoue, Yukinori; Yamada, Koji; Morimoto, Shigeo; Sanada, Masayuki

    This paper proposes a position sensorless drive system combined with on-line parameter identification for an interior permanent magnet synchronous motor. The accuracy of the position estimation can be improved by the proposed system, in which the motor parameters used for the position estimation are identified according to the operating conditions. First, the influence of the parameter error on the estimation position error is examined from the simulation and experimental results. Next, the characteristics of the sensorless drive system and the performance of parameter identification are shown. The experimental results show that the proposed system can achieve more accurate position estimation than the drive system without the parameter identification for all operating conditions.

  19. Investigation of CFRP in aerospace field and improvement of the molding accuracy by using autoclave

    Science.gov (United States)

    Minamisawa, Takunori

    2017-07-01

    In recent years, CFRP (Carbon Fiber Reinforced Plastic) has come to be used in a wide range of industries such as sporting goods, fishing tackle and cars because it has a large number of advantages. In this situation, even the passenger aircraft industry also pays attention to the material. CFRP is an ideal material for airplanes because it has a lot of advantages such as light weight and strong, chemical resistance and corrosion resistance. Generally, autoclave is used for molding CFRP in the field of aerospace engineering. Autoclave is a machine that can mold a product by heating and pressurizing material in an evacuated bag. What is examined in this paper is an observation on handmade CFRP by a polarizing microscope. In addition, mechanical characteristics were investigated. Furthermore, an improvement of accuracy in CFRP molding using an autoclave is suggested from viewpoint of thermodynamics.

  20. Improving the Accuracy of CT Colonography Interpretation: Computer-Aided Diagnosis

    Science.gov (United States)

    Summers, Ronald M.

    2010-01-01

    Synopsis Computer-aided polyp detection aims to improve the accuracy of the colonography interpretation. The computer searches the colonic wall to look for polyp-like protrusions and presents a list of suspicious areas to a physician for further analysis. Computer-aided polyp detection has developed rapidly over the past decade and in the laboratory setting and has sensitivities comparable to those of experts. Computer-aided polyp detection tends to help inexperienced readers more than experienced ones and may also lead to small reductions in specificity. In its currently proposed use as an adjunct to standard image interpretation, computer-aided polyp detection serves as a spellchecker rather than an efficiency enhancer. PMID:20451814

  1. A multi breed reference improves genotype imputation accuracy in Nordic Red cattle

    DEFF Research Database (Denmark)

    Brøndum, Rasmus Froberg; Ma, Peipei; Lund, Mogens Sandø

    2012-01-01

    the subsequent effect of the imputed HD data on the reliability of genomic prediction. HD genotype data was available for 247 Danish, 210 Swedish and 249 Finnish Red bulls, and for 546 Holstein bulls. A subset 50 of bulls from each of the Nordic Red populations was selected for validation. After quality control...... 612,615 SNPs on chromosome 1-29 remained for analysis. Validation was done by masking markers in true HD data and imputing them using Beagle v. 3.3 and a reference group of either national Red, combined Red or combined Red and Holstein bulls. Results show a decrease in allele error rate from 2.64, 1......The objective of this study was to investigate if a multi breed reference would improve genotype imputation accuracy from 50K to high density (HD) single nucleotide polymorphism (SNP) marker data in Nordic Red Dairy Cattle, compared to using only a single breed reference, and to check...

  2. A multi breed reference improves genotype imputation accuracy in Nordic Red cattle

    DEFF Research Database (Denmark)

    Brøndum, Rasmus Froberg; Ma, Peipei; Lund, Mogens Sandø

    the subsequent effect of the imputed HD data on the reliability of genomic prediction. HD genotype data was available for 247 Danish, 210 Swedish and 249 Finnish Red bulls, and for 546 Holstein bulls. A subset 50 of bulls from each of the Nordic Red populations was selected for validation. After quality control...... 612,615 SNPs on chromosome 1-29 remained for analysis. Validation was done by masking markers in true HD data and imputing them using Beagle v. 3.3 and a reference group of either national Red, combined Red or combined Red and Holstein bulls. Results show a decrease in allele error rate from 2.64, 1......The objective of this study was to investigate if a multi breed reference would improve genotype imputation accuracy from 50K to high density (HD) single nucleotide polymorphism (SNP) marker data in Nordic Red Dairy Cattle, compared to using only a single breed reference, and to check...

  3. Accuracy Improvement for Diabetes Disease Classification: A Case on a Public Medical Dataset

    Directory of Open Access Journals (Sweden)

    Mehrbakhsh Nilashi

    2017-09-01

    Full Text Available As a chronic disease, diabetes mellitus has emerged as a worldwide epidemic. Providing diagnostic aid for diabetes disease by using a set of data that contains only medical information obtained without advanced medical equipment, can help numbers of people who want to discover the disease or the risk of disease at an early stage. This can possibly make a huge positive impact on a lot of peoples lives. The aim of this study is to classify diabetes disease by developing an intelligence system using machine learning techniques. Our method is developed through clustering, noise removal and classification approaches. Accordingly, we use SOM, PCA and NN for clustering, noise removal and classification tasks, respectively. Experimental results on Pima Indian Diabetes dataset show that proposed method remarkably improves the accuracy of prediction in relation to methods developed in the previous studies. The hybrid intelligent system can assist medical practitioners in the healthcare practice as a decision support system.

  4. Accuracy of weight estimation by the Broselow tape is substantially improved by including a visual assessment of body habitus.

    Science.gov (United States)

    Wells, Mike; Goldstein, Lara; Bentley, Alison

    2017-10-18

    BackgroundThe Broselow tape (BT) has been shown to estimate weight poorly primarily because of variations in body habitus. The manufacturers have suggested that a visual assessment of habitus may be used to increase its performance. This study evaluated the ability of habitus-modified models to improve the accuracy thereof.MethodsA post hoc analysis of prospectively collected data from four hospitals in Johannesburg, South Africa, on a population of 1,085 children. Sixteen a priori models generated a modified weight estimation or drug dose based on the BT weight and a gestalt assessment of habitus.ResultsThe habitus-modified method suggested by the manufacturer did not improve the accuracy of the BT. Five dosing and four weight-estimation models were identified that markedly improved dosing and weight estimation accuracy, respectively. The best dosing model improved dosing accuracy (doses within 10% of correct dose) from 52.0 to 69.6% and reduced critical dosing errors from 16.5 to 4.3%. The best weight-estimation model improved accuracy from 59.4 to 81.9% and reduced critical errors from 11.8 to 1.9%.ConclusionThe accuracy of the BT as a drug-dosing and weight-estimation device can be substantially improved by including an appraisal of body habitus in the methodology.Pediatric Research advance online publication, 18 October 2017; doi:10.1038/pr.2017.222.

  5. Design Optimization for the Measurement Accuracy Improvement of a Large Range Nanopositioning Stage

    Directory of Open Access Journals (Sweden)

    Marta Torralba

    2016-01-01

    Full Text Available Both an accurate machine design and an adequate metrology loop definition are critical factors when precision positioning represents a key issue for the final system performance. This article discusses the error budget methodology as an advantageous technique to improve the measurement accuracy of a 2D-long range stage during its design phase. The nanopositioning platform NanoPla is here presented. Its specifications, e.g., XY-travel range of 50 mm × 50 mm and sub-micrometric accuracy; and some novel designed solutions, e.g., a three-layer and two-stage architecture are described. Once defined the prototype, an error analysis is performed to propose improvement design features. Then, the metrology loop of the system is mathematically modelled to define the propagation of the different sources. Several simplifications and design hypothesis are justified and validated, including the assumption of rigid body behavior, which is demonstrated after a finite element analysis verification. The different error sources and their estimated contributions are enumerated in order to conclude with the final error values obtained from the error budget. The measurement deviations obtained demonstrate the important influence of the working environmental conditions, the flatness error of the plane mirror reflectors and the accurate manufacture and assembly of the components forming the metrological loop. Thus, a temperature control of ±0.1 °C results in an acceptable maximum positioning error for the developed NanoPla stage, i.e., 41 nm, 36 nm and 48 nm in X-, Y- and Z-axis, respectively.

  6. Using spectrotemporal indices to improve the fruit-tree crop classification accuracy

    Science.gov (United States)

    Peña, M. A.; Liao, R.; Brenning, A.

    2017-06-01

    This study assesses the potential of spectrotemporal indices derived from satellite image time series (SITS) to improve the classification accuracy of fruit-tree crops. Six major fruit-tree crop types in the Aconcagua Valley, Chile, were classified by applying various linear discriminant analysis (LDA) techniques on a Landsat-8 time series of nine images corresponding to the 2014-15 growing season. As features we not only used the complete spectral resolution of the SITS, but also all possible normalized difference indices (NDIs) that can be constructed from any two bands of the time series, a novel approach to derive features from SITS. Due to the high dimensionality of this ;enhanced; feature set we used the lasso and ridge penalized variants of LDA (PLDA). Although classification accuracies yielded by the standard LDA applied on the full-band SITS were good (misclassification error rate, MER = 0.13), they were further improved by 23% (MER = 0.10) with ridge PLDA using the enhanced feature set. The most important bands to discriminate the crops of interest were mainly concentrated on the first two image dates of the time series, corresponding to the crops' greenup stage. Despite the high predictor weights provided by the red and near infrared bands, typically used to construct greenness spectral indices, other spectral regions were also found important for the discrimination, such as the shortwave infrared band at 2.11-2.19 μm, sensitive to foliar water changes. These findings support the usefulness of spectrotemporal indices in the context of SITS-based crop type classifications, which until now have been mainly constructed by the arithmetic combination of two bands of the same image date in order to derive greenness temporal profiles like those from the normalized difference vegetation index.

  7. The contribution of educational class in improving accuracy of cardiovascular risk prediction across European regions

    DEFF Research Database (Denmark)

    Ferrario, Marco M; Veronesi, Giovanni; Chambless, Lloyd E

    2014-01-01

    .3%) and in Eastern Europe and Russia (NRI=24.7%). In women, after SCORE risk adjustment, the association was not statistically significant, but the reduced number of deaths plays a major role, and the addition of education led to improvements in discrimination and classification in the Nordic countries only......OBJECTIVE: To assess whether educational class, an index of socioeconomic position, improves the accuracy of the SCORE cardiovascular disease (CVD) risk prediction equation. METHODS: In a pooled analysis of 68 455 40-64-year-old men and women, free from coronary heart disease at baseline, from 47...... improvement (NRI)) when education was added to models including the SCORE risk equation. RESULTS: The lowest educational class was associated with higher CVD mortality in men (pooled age-adjusted HR=1.64, 95% CI 1.42 to 1.90) and women (HR=1.31, 1.02 to 1.68). In men, the HRs ranged from 1.3 (Central Europe...

  8. An improved genetic algorithm for increasing the addressing accuracy of encoding fiber Bragg grating sensor network

    Science.gov (United States)

    Liu, Huanlin; Wang, Chujun; Chen, Yong

    2018-01-01

    Large-capacity encoding fiber Bragg grating (FBG) sensor network is widely used in modern long-term health monitoring system. Encoding FBG sensors have greatly improved the capacity of distributed FBG sensor network. However, the error of addressing increases correspondingly with the enlarging of capacity. To address the issue, an improved algorithm called genetic tracking algorithm (GTA) is proposed in the paper. In the GTA, for improving the success rate of matching and reducing the large number of redundant matching operations generated by sequential matching, the individuals are designed based on the feasible matching. Then, two kinds of self-crossover ways and a dynamic variation during mutation process are designed to increase the diversity of individuals and to avoid falling into local optimum. Meanwhile, an assistant decision is proposed to handle the issue that the GTA cannot solve when the variation of sensor information is highly overlapped. The simulation results indicate that the proposed GTA has higher accuracy compared with the traditional tracking algorithm and the enhanced tracking algorithm. In order to address the problems of spectrum fragmentation and low sharing degree of spectrum resources in survivable.

  9. Creatinine Assay Attainment of Analytical Performance Goals Following Implementation of IDMS Standardization

    OpenAIRE

    Elizabeth Sunmin Lee; Christine P Collier; White, Christine A.

    2017-01-01

    Background: The international initiative to standardize creatinine (Cr) assays by tracing reference materials to Isotope Dilution Mass Spectrometry (IDMS) assigned values was implemented to reduce interlaboratory variability and improve assay accuracy. Objective: The aims of this study were to examine whether IDMS standardization has improved Cr assay accuracy (bias), interlaboratory variability (precision), total error (TE), and attainment of recommended analytical performance goals. Methods...

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

    Science.gov (United States)

    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.

  11. A method for improved accuracy in three dimensions for determining wheel/rail contact points

    Science.gov (United States)

    Yang, Xinwen; Gu, Shaojie; Zhou, Shunhua; Zhou, Yu; Lian, Songliang

    2015-11-01

    Searching for the contact points between wheels and rails is important because these points represent the points of exerted contact forces. In order to obtain an accurate contact point and an in-depth description of the wheel/rail contact behaviours on a curved track or in a turnout, a method with improved accuracy in three dimensions is proposed to determine the contact points and the contact patches between the wheel and the rail when considering the effect of the yaw angle and the roll angle on the motion of the wheel set. The proposed method, with no need of the curve fitting of the wheel and rail profiles, can accurately, directly, and comprehensively determine the contact interface distances between the wheel and the rail. The range iteration algorithm is used to improve the computation efficiency and reduce the calculation required. The present computation method is applied for the analysis of the contact of rails of CHINA (CHN) 75 kg/m and wheel sets of wearing type tread of China's freight cars. In addition, it can be proved that the results of the proposed method are consistent with that of Kalker's program CONTACT, and the maximum deviation from the wheel/rail contact patch area of this two methods is approximately 5%. The proposed method, can also be used to investigate static wheel/rail contact. Some wheel/rail contact points and contact patch distributions are discussed and assessed, wheel and rail non-worn and worn profiles included.

  12. Improving diagnostic accuracy using agent-based distributed data mining system.

    Science.gov (United States)

    Sridhar, S

    2013-09-01

    The use of data mining techniques to improve the diagnostic system accuracy is investigated in this paper. The data mining algorithms aim to discover patterns and extract useful knowledge from facts recorded in databases. Generally, the expert systems are constructed for automating diagnostic procedures. The learning component uses the data mining algorithms to extract the expert system rules from the database automatically. Learning algorithms can assist the clinicians in extracting knowledge automatically. As the number and variety of data sources is dramatically increasing, another way to acquire knowledge from databases is to apply various data mining algorithms that extract knowledge from data. As data sets are inherently distributed, the distributed system uses agents to transport the trained classifiers and uses meta learning to combine the knowledge. Commonsense reasoning is also used in association with distributed data mining to obtain better results. Combining human expert knowledge and data mining knowledge improves the performance of the diagnostic system. This work suggests a framework of combining the human knowledge and knowledge gained by better data mining algorithms on a renal and gallstone data set.

  13. Coval: improving alignment quality and variant calling accuracy for next-generation sequencing data.

    Directory of Open Access Journals (Sweden)

    Shunichi Kosugi

    Full Text Available Accurate identification of DNA polymorphisms using next-generation sequencing technology is challenging because of a high rate of sequencing error and incorrect mapping of reads to reference genomes. Currently available short read aligners and DNA variant callers suffer from these problems. We developed the Coval software to improve the quality of short read alignments. Coval is designed to minimize the incidence of spurious alignment of short reads, by filtering mismatched reads that remained in alignments after local realignment and error correction of mismatched reads. The error correction is executed based on the base quality and allele frequency at the non-reference positions for an individual or pooled sample. We demonstrated the utility of Coval by applying it to simulated genomes and experimentally obtained short-read data of rice, nematode, and mouse. Moreover, we found an unexpectedly large number of incorrectly mapped reads in 'targeted' alignments, where the whole genome sequencing reads had been aligned to a local genomic segment, and showed that Coval effectively eliminated such spurious alignments. We conclude that Coval significantly improves the quality of short-read sequence alignments, thereby increasing the calling accuracy of currently available tools for SNP and indel identification. Coval is available at http://sourceforge.net/projects/coval105/.

  14. Research on six degrees of freedom compound control technology for improving photoelectric pod pointing accuracy

    Science.gov (United States)

    Zhou, Junpeng; Li, Yan; Chen, Juan; Nian, Lun; Zhang, Haibo

    2017-08-01

    High line-of-sight (LOS) pointing precision is a prerequisite for improving the laser confrontation capability of a photoelectric interference pod. In a traditional photoelectric pod, the time delay in TV tracking reduces the system phase margin, system stability and LOS pointing precision. In view of this deficiency, a normalized LMS algorithm is introduced to compensate for the TV camera delay in the inner gimbal position loop of a two-axis and four-gimbal structure, which can allow a pod to avoid system phase margin reduction. Meanwhile, a fast steering mirror (FSM) system is used to improve the LOS pointing precision. First, this paper proposes a normalized LMS algorithm. Second, a compound control structure, with an outer gimbal analog controller and an inner gimbal lag-lead controller, is designed. Finally, the FSM beam control precision is analyzed. The experimental results show that the normalized LMS algorithm yields almost no delay; moreover, the azimuth and pitch beam control accuracies are greater by a factor of 15 and 3, respectively, compared with those of a conventional photoelectric pod.

  15. Improving protein fold recognition and structural class prediction accuracies using physicochemical properties of amino acids.

    Science.gov (United States)

    Raicar, Gaurav; Saini, Harsh; Dehzangi, Abdollah; Lal, Sunil; Sharma, Alok

    2016-08-07

    Predicting the three-dimensional (3-D) structure of a protein is an important task in the field of bioinformatics and biological sciences. However, directly predicting the 3-D structure from the primary structure is hard to achieve. Therefore, predicting the fold or structural class of a protein sequence is generally used as an intermediate step in determining the protein's 3-D structure. For protein fold recognition (PFR) and structural class prediction (SCP), two steps are required - feature extraction step and classification step. Feature extraction techniques generally utilize syntactical-based information, evolutionary-based information and physicochemical-based information to extract features. In this study, we explore the importance of utilizing the physicochemical properties of amino acids for improving PFR and SCP accuracies. For this, we propose a Forward Consecutive Search (FCS) scheme which aims to strategically select physicochemical attributes that will supplement the existing feature extraction techniques for PFR and SCP. An exhaustive search is conducted on all the existing 544 physicochemical attributes using the proposed FCS scheme and a subset of physicochemical attributes is identified. Features extracted from these selected attributes are then combined with existing syntactical-based and evolutionary-based features, to show an improvement in the recognition and prediction performance on benchmark datasets. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. A simple bioscore improves diagnostic accuracy of sepsis after surgery.

    Science.gov (United States)

    Liu, Zimeng; Chen, Juan; Liu, Yongjun; Si, Xiang; Jiang, Zhiyi; Zhang, Xuyu; Guan, Xiangdong

    2016-01-01

    Rapid and accurate prediction for sepsis remains a challenge in surgical intensive care units. Detection of individual biomarkers is often of marginal usefulness, and several biomarkers are difficult to measure in the clinical setting. The aim of this study was to evaluate the diagnostic and prognostic performance of three routine biomarkers, procalcitonin (PCT), B-type natriuretic peptide (BNP), and lymphocyte percentage, as individual or in combination for sepsis in surgical critically ill patients. Circulating PCT, BNP, and lymphocyte percentage were measured in surgical patients on admission to the intensive care unit. A bioscore system combining these biomarkers was constructed. All studied variables were analyzed according to the diagnosis and clinical outcomes of sepsis. A total of 320 consecutive patients were included in the analysis. One hundred fifty-six patients presented with sepsis. In the patients with sepsis, levels of PCT and BNP increased and lymphocyte percentage decreased. For individual biomarkers, PCT achieved the best area under the curve for the diagnosis of sepsis, whereas the diagnostic performance of the bioscore was better than that of each individual biomarker (area under the curve, 0.914 [95% confidence interval, 0.862-0.951]). Levels of BNP and bioscore increased in nonsurvivors in the entire cohort, but the accuracy of these two variables for mortality prediction was lower than that shown by Acute Physiology and Chronic Health Evaluation II score. Furthermore, bioscore failed to predict outcomes in septic patients. A simple bioscore combining PCT together with BNP and lymphocyte percentage improves the diagnostic accuracy for sepsis in surgical critically ill patients but fails to predict outcomes in surgical patients with sepsis. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Improvement of the accuracy in the optical hematocrit measurement by optimizing mean optical path length.

    Science.gov (United States)

    Oshima, Shiori; Sankai, Yoshiyuki

    2009-09-01

    Optical techniques have been developed to acquire blood information (e.g., hematocrit [Hct], saturation of oxygen, thrombus) noninvasively and continuously in an artificial heart. For the practical use of an optical Hct measurement, Twersky's theory has been shown to be useful and have a good agreement in forward-scattered measurements. However, it was not applied to backward-scattered measurements, which can provide the measurement with a less demanding spatial requirement. Additionally, optimal measurement for accuracy is not well examined. Therefore, we developed an accurate Hct measurement in an artificial heart using current optical devices. To this end, we focused on optimizing an emitter-detector distance to provide a maximum optical path length. We attached optical emitter and detector fibers on Tygon tubing at various distances to measure forward- and backward-scattered light. Fresh bovine blood (Hct: 30-50%) was circulated in the tubing by a nonpulsatile artificial heart. We calculated the optical path length at various emitter-detector distances by fitting the measured optical outputs and the reference Hcts to Twersky's theory. Then, we performed Hct measurements. As a result, Twersky's theory is applicable not only to forward- but also to backward-scattered measurements in the physiogical Hct range. In both forward- and backward-scattered measurements, calculated optical path lengths become maximum at the same emitter-detector distance. The accuracy of Hct measurement is improved two to three times with the emitter-detector distance compared with other distances. The mean error is less than 1 Hct%. This result shows that an accurate Hct measurement is realized by selecting the optimal emitter-detector distance, which provides maximum optical path length defined by Twersky's theory. Our study provides a framework for the practical and less restrictive application of the optical Hct measurement to patients with an artificial heart.

  18. Can use of an administrative database improve accuracy of hospital-reported readmission rates?

    Science.gov (United States)

    Edgerton, James R; Herbert, Morley A; Hamman, Baron L; Ring, W Steves

    2017-12-05

    Readmission rates after cardiac surgery are being used as a quality indicator; they are also being collected by Medicare and are tied to reimbursement. Accurate knowledge of readmission rates may be difficult to achieve because patients may be readmitted to different hospitals. In our area, 81 hospitals share administrative claims data; 28 of these hospitals (from 5 different hospital systems) do cardiac surgery and share Society of Thoracic Surgeons (STS) clinical data. We used these 2 sources to compare the readmissions data for accuracy. A total of 45,539 STS records from January 2008 to December 2016 were matched with the hospital billing data records. Using the index visit as the start date, the billing records were queried for any subsequent in-patient visits for that patient. The billing records included date of readmission and hospital of readmission data and were compared with the data captured in the STS record. We found 1153 (2.5%) patients who had STS records that were marked "No" or "missing," but there were billing records that showed a readmission. The reported STS readmission rate of 4796 (10.5%) underreported the readmission rate by 2.5 actual percentage points. The true rate should have been 13.0%. Actual readmission rate was 23.8% higher than reported by the clinical database. Approximately 36% of readmissions were to a hospital that was a part of a different hospital system. It is important to know accurate readmission rates for quality improvement processes and institutional financial planning. Matching patient records to an administrative database showed that the clinical database may fail to capture many readmissions. Combining data with an administrative database can enhance accuracy of reporting. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  19. Study on Improvement of Accuracy in Inertial Photogrammetry by Combining Images with Inertial Measurement Unit

    Science.gov (United States)

    Kawasaki, Hideaki; Anzai, Shojiro; Koizumi, Toshio

    2016-06-01

    Inertial photogrammetry is defined as photogrammetry that involves using a camera on which an inertial measurement unit (IMU) is mounted. In inertial photogrammetry, the position and inclination of a shooting camera are calculated using the IMU. An IMU is characterized by error growth caused by time accumulation because acceleration is integrated with respect to time. This study examines the procedure to estimate the position of the camera accurately while shooting using the IMU and the structure from motion (SfM) technology, which is applied in many fields, such as computer vision. When neither the coordinates of the position of the camera nor those of feature points are known, SfM provides a similar positional relationship between the position of the camera and feature points. Therefore, the actual length of positional coordinates is not determined. If the actual length of the position of the camera is unknown, the camera acceleration is obtained by calculating the second order differential of the position of the camera, with respect to the shooting time. The authors had determined the actual length by assigning the position of IMU to the SfM-calculated position. Hence, accuracy decreased because of the error growth, which was the characteristic feature of IMU. In order to solve this problem, a new calculation method was proposed. Using this method, the difference between the IMU-calculated acceleration and the camera-calculated acceleration can be obtained using the method of least squares, and the magnification required for calculating the actual dimension from the position of the camera can be obtained. The actual length can be calculated by multiplying all the SfM point groups by the obtained magnification factor. This calculation method suppresses the error growth, which is due to the time accumulation in IMU, and improves the accuracy of inertial photogrammetry.

  20. An improved Abbott ARCHITECT assay for the detection of hepatitis B virus surface antigen (HBsAg).

    Science.gov (United States)

    Lou, Sheng C; Pearce, Sandra K; Lukaszewska, Teresa X; Taylor, Russell E; Williams, Gregg T; Leary, Thomas P

    2011-05-01

    The sensitive and accurate detection of hepatitis B virus surface antigen (HBsAg) is critical to the identification of infection and the prevention of transfusion transmitted disease. Improvement in HBsAg assay sensitivity is essential to reduce the window to detect an acute HBV infection. Additionally, the sensitive detection of HBsAg mutants that continue to evolve due to vaccine escape, immune selection and an error prone reverse transcriptase is a necessity. A fully automated HBsAg prototype assay on the Abbott ARCHITECT instrument was developed to improve sensitivity and mutant detection. This magnetic microparticle-based assay utilizes anti-HBsAg monoclonal antibodies to capture antigen present in serum or plasma. Captured antigen is then detected using anti-HBsAg antibody conjugated with the chemiluminescent compound, acridinium. The sensitivity of the ARCHITECT HBsAg prototype assay was improved as compared to the current ARCHITECT, PRISM, and competitor HBsAg assays. The enhancement in assay sensitivity was demonstrated by the use of commercially available HBV seroconversion panels. The prototype assay detected more panel members (185 of 383) vs. the current ARCHITECT (171), PRISM (181), or competitor HBsAg assays (73/140 vs. 62/140, respectively). The ARCHITECT prototype assay also efficiently detected all mutants evaluated. Finally, the sensitivity improvement did not compromise the specificity of the assay (99.94%). An improved Abbott ARCHITECT HBsAg prototype assay with enhanced detection of HBsAg and HBsAg mutants, as well as equivalent specificity was developed for the detection, diagnosis, and management of HBV infection. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Improved mass spectrometry assay for plasma hepcidin: detection and characterization of a novel hepcidin isoform.

    Directory of Open Access Journals (Sweden)

    Coby M M Laarakkers

    Full Text Available Mass spectrometry (MS-based assays for the quantification of the iron regulatory hormone hepcidin are pivotal to discriminate between the bioactive 25-amino acid form that can effectively block the sole iron transporter ferroportin and other naturally occurring smaller isoforms without a known role in iron metabolism. Here we describe the design, validation and use of a novel stable hepcidin-25(+40 isotope as internal standard for quantification. Importantly, the relative large mass shift of 40 Da makes this isotope also suitable for easy-to-use medium resolution linear time-of-flight (TOF platforms. As expected, implementation of hepcidin-25(+40 as internal standard in our weak cation exchange (WCX TOF MS method yielded very low inter/intra run coefficients of variation. Surprisingly, however, in samples from kidney disease patients, we detected a novel peak (m/z 2673.9 with low intensity that could be identified as hepcidin-24 and had previously remained unnoticed due to peak interference with the formerly used internal standard. Using a cell-based bioassay it was shown that synthetic hepcidin-24 was, like the -22 and -20 isoforms, a significantly less potent inducer of ferroportin degradation than hepcidin-25. During prolonged storage of plasma at room temperature, we observed that a decrease in plasma hepcidin-25 was paralleled by an increase in the levels of the hepcidin-24, -22 and -20 isoforms. This provides first evidence that all determinants for the conversion of hepcidin-25 to smaller inactive isoforms are present in the circulation, which may contribute to the functional suppression of hepcidin-25, that is significantly elevated in patients with renal impairment. The present update of our hepcidin TOF MS assay together with improved insights in the source and preparation of the internal standard, and sample stability will further improve our understanding of circulating hepcidin and pave the way towards further optimization and

  2. Improved mass spectrometry assay for plasma hepcidin: detection and characterization of a novel hepcidin isoform.

    Science.gov (United States)

    Laarakkers, Coby M M; Wiegerinck, Erwin T; Klaver, Siem; Kolodziejczyk, Maria; Gille, Hendrik; Hohlbaum, Andreas M; Tjalsma, Harold; Swinkels, Dorine W

    2013-01-01

    Mass spectrometry (MS)-based assays for the quantification of the iron regulatory hormone hepcidin are pivotal to discriminate between the bioactive 25-amino acid form that can effectively block the sole iron transporter ferroportin and other naturally occurring smaller isoforms without a known role in iron metabolism. Here we describe the design, validation and use of a novel stable hepcidin-25(+40) isotope as internal standard for quantification. Importantly, the relative large mass shift of 40 Da makes this isotope also suitable for easy-to-use medium resolution linear time-of-flight (TOF) platforms. As expected, implementation of hepcidin-25(+40) as internal standard in our weak cation exchange (WCX) TOF MS method yielded very low inter/intra run coefficients of variation. Surprisingly, however, in samples from kidney disease patients, we detected a novel peak (m/z 2673.9) with low intensity that could be identified as hepcidin-24 and had previously remained unnoticed due to peak interference with the formerly used internal standard. Using a cell-based bioassay it was shown that synthetic hepcidin-24 was, like the -22 and -20 isoforms, a significantly less potent inducer of ferroportin degradation than hepcidin-25. During prolonged storage of plasma at room temperature, we observed that a decrease in plasma hepcidin-25 was paralleled by an increase in the levels of the hepcidin-24, -22 and -20 isoforms. This provides first evidence that all determinants for the conversion of hepcidin-25 to smaller inactive isoforms are present in the circulation, which may contribute to the functional suppression of hepcidin-25, that is significantly elevated in patients with renal impairment. The present update of our hepcidin TOF MS assay together with improved insights in the source and preparation of the internal standard, and sample stability will further improve our understanding of circulating hepcidin and pave the way towards further optimization and standardization of

  3. Improved cumulative probabilities and range accuracy of a pulsed Geiger-mode avalanche photodiode laser ranging system with turbulence effects.

    Science.gov (United States)

    Luo, Hanjun; Ouyang, Zhengbiao; Liu, Qiang; Lu, Zhenli; Li, Bin

    2017-10-10

    There exists a performance limitation in a pulsed Geiger-mode avalanche photodiode laser ranging system because of the echo intensity random fluctuation caused by turbulence effects. To suppress the influence of turbulence effects, we present a cumulative pulse detection technique with the ability to achieve improved cumulative probabilities and range accuracy. Based on the modulated Poisson model, the cumulative probabilities, range accuracy, and their influencing factors are investigated for a cumulative Q-switched laser pulse train. The results show that the improved cumulative probabilities and range accuracy can be obtained by utilizing cumulative pulse detection, with the condition that the echo intensity is 10, the echo pulse width is 10 ns, and the turbulence degree is 3, the target detection probability increases by 0.4, the false alarm probability decreases by 0.08, and the accuracy and precision increase by 46 cm and 27 cm, respectively.

  4. Using NAPIIA to improve the accuracy of Asian race codes in registry data.

    Science.gov (United States)

    Hsieh, Mei-Chin; Pareti, Lisa A; Chen, Vivien W

    2011-01-01

    Misclassification of race/ethnicity, particularly for Asians and American Indians, has been an issue existing in cancer registry data for years. Over the past 10 years, the Asian population has increased noticeably in both the US and in Louisiana. Therefore, accurate recording of Asian races/ethnicities in cancer registry databases has become essential for disparity research. The objectives of this study were to demonstrate that using the North American Association of Central Cancer Registries (NAACCR) Asian/Pacific Islander Identification Algorithm (NAPIIA) could improve the coding accuracy of Asian ethnicities and to identify sources for manually verifying race/ethnicity. We selected cases diagnosed in years 1995 to 2008 with first race (NAACCR item 160) coded to any Asians, other race, unknown race, or non-Asian race with birthplace in an Asian country. We then converted these races to Asian, Not Otherwise Specified (Asian NOS) race code 96 and applied NAPIIA on the records. The resultant Asian races/ethnicities assigned by NAPIIA were then compared to the original race. When the NAPIIA-assigned Asian codes were different from the original race, the cases were manually reviewed. Kappa statistic test was used to measure the interobserver agreement; sensitivity and positive predictive value (PPV) were used to assess the degree of discrepancy for each Asian racial/ethnic subgroup separately. Of 2,147 cases run through the NAPIIA, 22.3% (479) were identified with coding discrepancies. Overall, the agreement on Asian subgroups between the original and NAPIIA-assigned was almost perfect (Kappa = 0.8682). When NAPIIA-assigned race and manually reviewed race were compared, the Vietnamese subgroup had the highest consistent rate (95%). Of the 237 cases where the original race was coded to Asian NOS, 93.7% were verified as having a more specific race/ethnicity. Slightly over 98% of deceased patients found in Louisiana online death certificate database had specific race

  5. Improving accuracy and precision in biological applications of fluorescence lifetime imaging microscopy

    Science.gov (United States)

    Chang, Ching-Wei

    The quantitative understanding of cellular and molecular responses in living cells is important for many reasons, including identifying potential molecular targets for treatments of diseases like cancer. Fluorescence lifetime imaging microscopy (FLIM) can quantitatively measure these responses in living cells by producing spatially resolved images of fluorophore lifetime, and has advantages over intensity-based measurements. However, in live-cell microscopy applications using high-intensity light sources such as lasers, maintaining biological viability remains critical. Although high-speed, time-gated FLIM significantly reduces light delivered to live cells, making measurements at low light levels remains a challenge affecting quantitative FLIM results. We can significantly improve both accuracy and precision in gated FLIM applications. We use fluorescence resonance energy transfer (FRET) with fluorescent proteins to detect molecular interactions in living cells: the use of FLIM, better fluorophores, and temperature/CO2 controls can improve live-cell FRET results with higher consistency, better statistics, and less non-specific FRET (for negative control comparisons, p-value = 0.93 (physiological) vs. 9.43E-05 (non-physiological)). Several lifetime determination methods are investigated to optimize gating schemes. We demonstrate a reduction in relative standard deviation (RSD) from 52.57% to 18.93% with optimized gating in an example under typical experimental conditions. We develop two novel total variation (TV) image denoising algorithms, FWTV ( f-weighted TV) and UWTV (u-weighted TV), that can achieve significant improvements for real imaging systems. With live-cell images, they improve the precision of local lifetime determination without significantly altering the global mean lifetime values (high-light cases (RSD = 12.76% at total photon counts (TC) = 100 vs. RSD = 23.03% at TC = 400). Therefore, high-intensity excitation of living cells can be avoided

  6. Signal processing of MEMS gyroscope arrays to improve accuracy using a 1st order Markov for rate signal modeling.

    Science.gov (United States)

    Jiang, Chengyu; Xue, Liang; Chang, Honglong; Yuan, Guangmin; Yuan, Weizheng

    2012-01-01

    This paper presents a signal processing technique to improve angular rate accuracy of the gyroscope by combining the outputs of an array of MEMS gyroscope. A mathematical model for the accuracy improvement was described and a Kalman filter (KF) was designed to obtain optimal rate estimates. Especially, the rate signal was modeled by a first-order Markov process instead of a random walk to improve overall performance. The accuracy of the combined rate signal and affecting factors were analyzed using a steady-state covariance. A system comprising a six-gyroscope array was developed to test the presented KF. Experimental tests proved that the presented model was effective at improving the gyroscope accuracy. The experimental results indicated that six identical gyroscopes with an ARW noise of 6.2 °/√h and a bias drift of 54.14 °/h could be combined into a rate signal with an ARW noise of 1.8 °/√h and a bias drift of 16.3 °/h, while the estimated rate signal by the random walk model has an ARW noise of 2.4 °/√h and a bias drift of 20.6 °/h. It revealed that both models could improve the angular rate accuracy and have a similar performance in static condition. In dynamic condition, the test results showed that the first-order Markov process model could reduce the dynamic errors 20% more than the random walk model.

  7. An adaptive grid to improve the efficiency and accuracy of modelling underwater noise from shipping

    Science.gov (United States)

    Trigg, Leah; Chen, Feng; Shapiro, Georgy; Ingram, Simon; Embling, Clare

    2017-04-01

    represents a 2 to 5-fold increase in efficiency. The 5 km grid reduces the number of model executions further to 1024. However, over the first 25 km the 5 km grid produces errors of up to 13.8 dB when compared to the highly accurate but inefficient 1 km grid. The newly developed adaptive grid generates much smaller errors of less than 0.5 dB while demonstrating high computational efficiency. Our results show that the adaptive grid provides the ability to retain the accuracy of noise level predictions and improve the efficiency of the modelling process. This can help safeguard sensitive marine ecosystems from noise pollution by improving the underwater noise predictions that inform management activities. References Shapiro, G., Chen, F., Thain, R., 2014. The Effect of Ocean Fronts on Acoustic Wave Propagation in a Shallow Sea, Journal of Marine System, 139: 217 - 226. http://dx.doi.org/10.1016/j.jmarsys.2014.06.007.

  8. Using Critical Discourse Analysis Based Instruction to Improve EFL Learners’ Writing Complexity, Accuracy and Fluency

    Directory of Open Access Journals (Sweden)

    Hamid Marashi

    2016-11-01

    Full Text Available The literature of ELT is perhaps overwhelmed by attempts to enhance learners’ writing through the application of different methodologies. One such methodology is critical discourse analysis which is founded upon stressing not only the decoding of the propositional meaning of a text but also its ideological assumptions. Accordingly, this study was an attempt to investigate the impact of critical discourse analysis-based (CDA instruction on EFL learners’ writing complexity, accuracy, and fluency (CAF. To fulfill the purpose of this study, 60 female intermediate EFL learners were selected from among a total number of 100 through their performance on a piloted sample PET. Based on the results, the students were randomly assigned to a control and an experimental group with 30 participants in each. Both groups underwent the same amount of teaching time during 17 sessions which included a treatment of CDA instruction for the experimental group. A writing posttest was administered at the end of the instruction to both groups and their mean scores on the test were compared through a MANOVA. The results led to the rejection of the three null hypotheses, thereby demonstrating that the learners in the experimental group benefited significantly more than those in the control group in terms of improving their writing CAF. To this end, it is recommended that CDA instruction be incorporated more frequently in writing classes following of course adequate syllabus design and materials development.

  9. Improving accuracy of total knee component cementation: description of a simple technique

    Directory of Open Access Journals (Sweden)

    Dayton Michael R

    2009-10-01

    Full Text Available Abstract Background Total knee arthroplasty represents a common orthopedic surgical procedure. Achieving proper alignment of its components with the predrilled patellar and tibial peg holes prior to polymerization of the bone cement can be challenging. Technique After establishing the femoral, patellar and tibial bone cuts, the cancellous bone around the tibial keel, as well as the peg holes for the patella and femoral components are marked with methylene blue using a cotton swab stick. If bone cement is then placed onto the cut and marked bone edges, the methylene blue leaches through the bone cement and clearly outlines the tibial keel and predrilled femoral and patellar peg holes. This allows excellent visualization of the bone preparations for each component, ensuring safe and prompt positioning of TKA components while minimizing intraoperative difficulties with component alignment while the cement hardens. Conclusion The presented technical note helps to improve the accuracy and ease of insertion when the components of total knee arthroplasty are impacted to their final position.

  10. Improvement of the prediction accuracy of polar motion using empirical mode decomposition

    Directory of Open Access Journals (Sweden)

    Yu Lei

    2017-03-01

    Full Text Available Previous studies revealed that the error of pole coordinate prediction will significantly increase for a prediction period longer than 100 days, and this is mainly caused by short period oscillations. Empirical mode decomposition (EMD, which is increasingly popular and has advantages over classical wavelet decomposition, can be used to remove short period variations from observed time series of pole coordinates. A hybrid model combing EMD and extreme learning machine (ELM, where high frequency signals are removed and processed time series is then modeled and predicted, is summarized in this paper. The prediction performance of the hybrid model is compared with that of the ELM-only method created from original time series. The results show that the proposed hybrid model outperforms the pure ELM method for both short-term and long-term prediction of pole coordinates. The improvement of prediction accuracy up to 360 days in the future is found to be 24.91% and 26.79% on average in terms of mean absolute error (MAE for the xp and yp components of pole coordinates, respectively.

  11. Improving the Accuracy of Urban Environmental Quality Assessment Using Geographically-Weighted Regression Techniques

    Science.gov (United States)

    Faisal, Kamil; Shaker, Ahmed

    2017-01-01

    Urban Environmental Quality (UEQ) can be treated as a generic indicator that objectively represents the physical and socio-economic condition of the urban and built environment. The value of UEQ illustrates a sense of satisfaction to its population through assessing different environmental, urban and socio-economic parameters. This paper elucidates the use of the Geographic Information System (GIS), Principal Component Analysis (PCA) and Geographically-Weighted Regression (GWR) techniques to integrate various parameters and estimate the UEQ of two major cities in Ontario, Canada. Remote sensing, GIS and census data were first obtained to derive various environmental, urban and socio-economic parameters. The aforementioned techniques were used to integrate all of these environmental, urban and socio-economic parameters. Three key indicators, including family income, higher level of education and land value, were used as a reference to validate the outcomes derived from the integration techniques. The results were evaluated by assessing the relationship between the extracted UEQ results and the reference layers. Initial findings showed that the GWR with the spatial lag model represents an improved precision and accuracy by up to 20% with respect to those derived by using GIS overlay and PCA techniques for the City of Toronto and the City of Ottawa. The findings of the research can help the authorities and decision makers to understand the empirical relationships among environmental factors, urban morphology and real estate and decide for more environmental justice. PMID:28272334

  12. Convex gradient optimization for increased spatiotemporal resolution and improved accuracy in phase contrast MRI.

    Science.gov (United States)

    Middione, Matthew J; Wu, Holden H; Ennis, Daniel B

    2014-12-01

    To evaluate convex gradient optimization (CVX) for increased spatiotemporal resolution and improved accuracy for phase-contrast MRI (PC-MRI). A conventional flow-compensated and flow-encoded (FCFE) PC-MRI sequence was compared with a CVX PC-MRI sequence using numerical simulations, flow phantom experiments, and in vivo experiments. Flow measurements within the ascending aorta, main pulmonary artery, and right/left pulmonary arteries of normal volunteers (N = 10) were acquired at 3T and analyzed using a conventional FCFE sequence and a CVX sequence with either higher spatial resolution or higher temporal resolution. All sequences mitigated chemical shift-induced phase errors and used equivalent breath-hold durations. Chemical shift-optimized PC-MRI has increased sequence efficiency when using CVX, which can provide either higher spatial or higher temporal resolution compared with conventional FCFE PC-MRI. Numerical simulations, flow phantom experiments, and in vivo experiments indicate that CVX measurements of total flow and peak velocity are increased and more accurate when compared with FCFE. CVX PC-MRI increases sequence efficiency while reducing chemical shift-induced phase errors. This can be used to provide either higher spatial or higher temporal resolution than conventional chemical shift-mitigated PC-MRI methods to provide more accurate measurements of blood flow and peak velocity. © 2013 Wiley Periodicals, Inc.

  13. Improving the Accuracy of Urban Environmental Quality Assessment Using Geographically-Weighted Regression Techniques.

    Science.gov (United States)

    Faisal, Kamil; Shaker, Ahmed

    2017-03-07

    Urban Environmental Quality (UEQ) can be treated as a generic indicator that objectively represents the physical and socio-economic condition of the urban and built environment. The value of UEQ illustrates a sense of satisfaction to its population through assessing different environmental, urban and socio-economic parameters. This paper elucidates the use of the Geographic Information System (GIS), Principal Component Analysis (PCA) and Geographically-Weighted Regression (GWR) techniques to integrate various parameters and estimate the UEQ of two major cities in Ontario, Canada. Remote sensing, GIS and census data were first obtained to derive various environmental, urban and socio-economic parameters. The aforementioned techniques were used to integrate all of these environmental, urban and socio-economic parameters. Three key indicators, including family income, higher level of education and land value, were used as a reference to validate the outcomes derived from the integration techniques. The results were evaluated by assessing the relationship between the extracted UEQ results and the reference layers. Initial findings showed that the GWR with the spatial lag model represents an improved precision and accuracy by up to 20% with respect to those derived by using GIS overlay and PCA techniques for the City of Toronto and the City of Ottawa. The findings of the research can help the authorities and decision makers to understand the empirical relationships among environmental factors, urban morphology and real estate and decide for more environmental justice.

  14. Accuracy improvement in a calibration test bench for accelerometers by a vision system

    Energy Technology Data Exchange (ETDEWEB)

    D’Emilia, Giulio, E-mail: giulio.demilia@univaq.it; Di Gasbarro, David, E-mail: david.digasbarro@graduate.univaq.it; Gaspari, Antonella, E-mail: antonella.gaspari@graduate.univaq.it; Natale, Emanuela, E-mail: emanuela.natale@univaq.it [University of L’Aquila, Department of Industrial and Information Engineering and Economics (DIIIE), via G. Gronchi, 18, 67100 L’Aquila (Italy)

    2016-06-28

    A procedure is described in this paper for the accuracy improvement of calibration of low-cost accelerometers in a prototype rotary test bench, driven by a brushless servo-motor and operating in a low frequency range of vibrations (0 to 5 Hz). Vibration measurements by a vision system based on a low frequency camera have been carried out, in order to reduce the uncertainty of the real acceleration evaluation at the installation point of the sensor to be calibrated. A preliminary test device has been realized and operated in order to evaluate the metrological performances of the vision system, showing a satisfactory behavior if the uncertainty measurement is taken into account. A combination of suitable settings of the control parameters of the motion control system and of the information gained by the vision system allowed to fit the information about the reference acceleration at the installation point to the needs of the procedure for static and dynamic calibration of three-axis accelerometers.

  15. Free Form Deformation–Based Image Registration Improves Accuracy of Traction Force Microscopy

    Science.gov (United States)

    Jorge-Peñas, Alvaro; Izquierdo-Alvarez, Alicia; Aguilar-Cuenca, Rocio; Vicente-Manzanares, Miguel; Garcia-Aznar, José Manuel; Van Oosterwyck, Hans; de-Juan-Pardo, Elena M.; Ortiz-de-Solorzano, Carlos; Muñoz-Barrutia, Arrate

    2015-01-01

    Traction Force Microscopy (TFM) is a widespread method used to recover cellular tractions from the deformation that they cause in their surrounding substrate. Particle Image Velocimetry (PIV) is commonly used to quantify the substrate’s deformations, due to its simplicity and efficiency. However, PIV relies on a block-matching scheme that easily underestimates the deformations. This is especially relevant in the case of large, locally non-uniform deformations as those usually found in the vicinity of a cell’s adhesions to the substrate. To overcome these limitations, we formulate the calculation of the deformation of the substrate in TFM as a non-rigid image registration process that warps the image of the unstressed material to match the image of the stressed one. In particular, we propose to use a B-spline -based Free Form Deformation (FFD) algorithm that uses a connected deformable mesh to model a wide range of flexible deformations caused by cellular tractions. Our FFD approach is validated in 3D fields using synthetic (simulated) data as well as with experimental data obtained using isolated endothelial cells lying on a deformable, polyacrylamide substrate. Our results show that FFD outperforms PIV providing a deformation field that allows a better recovery of the magnitude and orientation of tractions. Together, these results demonstrate the added value of the FFD algorithm for improving the accuracy of traction recovery. PMID:26641883

  16. Improving Sensing Accuracy in Cognitive PANs through Modulation of Sensing Probability

    Directory of Open Access Journals (Sweden)

    Vojislav B. Mišić

    2009-01-01

    Full Text Available Cognitive radio technology necessitates accurate and timely sensing of primary users' activity on the chosen set of channels. The simplest selection procedure is a simple random choice of channels to be sensed, but the impact of sensing errors with respect to primary user activity or inactivity differs considerably. In order to improve sensing accuracy and increase the likelihood of finding channels which are free from primary user activity, the selection procedure is modified by assigning different sensing probabilities to active and inactive channels. The paper presents a probabilistic analysis of this policy and investigates the range of values in which the modulation of sensing probability is capable of maintaining an accurate view of the status of the working channel set. We also present a modification of the probability modulation algorithm that allows for even greater reduction of sensing error in a limited range of the duty cycle of primary users' activity. Finally, we give some guidelines as to the optimum application ranges for the original and modified algorithm, respectively.

  17. CT reconstruction techniques for improved accuracy of lung CT airway measurement

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, A. [Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705 (United States); Ranallo, F. N. [Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705 and Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792 (United States); Judy, P. F. [Brigham and Women’s Hospital, Boston, Massachusetts 02115 (United States); Gierada, D. S. [Department of Radiology, Washington University, St. Louis, Missouri 63110 (United States); Fain, S. B., E-mail: sfain@wisc.edu [Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705 (United States); Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792 (United States); Department of Biomedical Engineering,University of Wisconsin School of Engineering, Madison, Wisconsin 53706 (United States)

    2014-11-01

    FBP. Veo reconstructions showed slight improvement over STD FBP reconstructions (4%–9% increase in accuracy). The most improved ID and WA% measures were for the smaller airways, especially for low dose scans reconstructed at half DFOV (18 cm) with the EDGE algorithm in combination with 100% ASIR to mitigate noise. Using the BONE + ASIR at half BONE technique, measures improved by a factor of 2 over STD FBP even at a quarter of the x-ray dose. Conclusions: The flexibility of ASIR in combination with higher frequency algorithms, such as BONE, provided the greatest accuracy for conventional and low x-ray dose relative to FBP. Veo provided more modest improvement in qCT measures, likely due to its compatibility only with the smoother STD kernel.

  18. CT reconstruction techniques for improved accuracy of lung CT airway measurement

    Science.gov (United States)

    Rodriguez, A.; Ranallo, F. N.; Judy, P. F.; Gierada, D. S.; Fain, S. B.

    2014-01-01

    FBP. Veo reconstructions showed slight improvement over STD FBP reconstructions (4%–9% increase in accuracy). The most improved ID and WA% measures were for the smaller airways, especially for low dose scans reconstructed at half DFOV (18 cm) with the EDGE algorithm in combination with 100% ASIR to mitigate noise. Using the BONE + ASIR at half BONE technique, measures improved by a factor of 2 over STD FBP even at a quarter of the x-ray dose. Conclusions: The flexibility of ASIR in combination with higher frequency algorithms, such as BONE, provided the greatest accuracy for conventional and low x-ray dose relative to FBP. Veo provided more modest improvement in qCT measures, likely due to its compatibility only with the smoother STD kernel. PMID:25370644

  19. Improving the accuracy of vehicle emissions profiles for urban transportation greenhouse gas and air pollution inventories.

    Science.gov (United States)

    Reyna, Janet L; Chester, Mikhail V; Ahn, Soyoung; Fraser, Andrew M

    2015-01-06

    Metropolitan greenhouse gas and air emissions inventories can better account for the variability in vehicle movement, fleet composition, and infrastructure that exists within and between regions, to develop more accurate information for environmental goals. With emerging access to high quality data, new methods are needed for informing transportation emissions assessment practitioners of the relevant vehicle and infrastructure characteristics that should be prioritized in modeling to improve the accuracy of inventories. The sensitivity of light and heavy-duty vehicle greenhouse gas (GHG) and conventional air pollutant (CAP) emissions to speed, weight, age, and roadway gradient are examined with second-by-second velocity profiles on freeway and arterial roads under free-flow and congestion scenarios. By creating upper and lower bounds for each factor, the potential variability which could exist in transportation emissions assessments is estimated. When comparing the effects of changes in these characteristics across U.S. cities against average characteristics of the U.S. fleet and infrastructure, significant variability in emissions is found to exist. GHGs from light-duty vehicles could vary by -2%-11% and CAP by -47%-228% when compared to the baseline. For heavy-duty vehicles, the variability is -21%-55% and -32%-174%, respectively. The results show that cities should more aggressively pursue the integration of emerging big data into regional transportation emissions modeling, and the integration of these data is likely to impact GHG and CAP inventories and how aggressively policies should be implemented to meet reductions. A web-tool is developed to aide cities in improving emissions uncertainty.

  20. Model-based reconstruction for real-time phase-contrast flow MRI: Improved spatiotemporal accuracy.

    Science.gov (United States)

    Tan, Zhengguo; Roeloffs, Volkert; Voit, Dirk; Joseph, Arun A; Untenberger, Markus; Merboldt, K Dietmar; Frahm, Jens

    2017-03-01

    To develop a model-based reconstruction technique for real-time phase-contrast flow MRI with improved spatiotemporal accuracy in comparison to methods using phase differences of two separately reconstructed images with differential flow encodings. The proposed method jointly computes a common image, a phase-contrast map, and a set of coil sensitivities from every pair of flow-compensated and flow-encoded datasets obtained by highly undersampled radial FLASH. Real-time acquisitions with five and seven radial spokes per image resulted in 25.6 and 35.7 ms measuring time per phase-contrast map, respectively. The signal model for phase-contrast flow MRI requires the solution of a nonlinear inverse problem, which is accomplished by an iteratively regularized Gauss-Newton method. Aspects of regularization and scaling are discussed. The model-based reconstruction was validated for a numerical and experimental flow phantom and applied to real-time phase-contrast MRI of the human aorta for 10 healthy subjects and 2 patients. Under all conditions, and compared with a previously developed real-time flow MRI method, the proposed method yields quantitatively accurate phase-contrast maps (i.e., flow velocities) with improved spatial acuity, reduced phase noise and reduced streaking artifacts. This novel model-based reconstruction technique may become a new tool for clinical flow MRI in real time. Magn Reson Med 77:1082-1093, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  1. An expanded evaluation of protein function prediction methods shows an improvement in accuracy.

    Science.gov (United States)

    Jiang, Yuxiang; Oron, Tal Ronnen; Clark, Wyatt T; Bankapur, Asma R; D'Andrea, Daniel; Lepore, Rosalba; Funk, Christopher S; Kahanda, Indika; Verspoor, Karin M; Ben-Hur, Asa; Koo, Da Chen Emily; Penfold-Brown, Duncan; Shasha, Dennis; Youngs, Noah; Bonneau, Richard; Lin, Alexandra; Sahraeian, Sayed M E; Martelli, Pier Luigi; Profiti, Giuseppe; Casadio, Rita; Cao, Renzhi; Zhong, Zhaolong; Cheng, Jianlin; Altenhoff, Adrian; Skunca, Nives; Dessimoz, Christophe; Dogan, Tunca; Hakala, Kai; Kaewphan, Suwisa; Mehryary, Farrokh; Salakoski, Tapio; Ginter, Filip; Fang, Hai; Smithers, Ben; Oates, Matt; Gough, Julian; Törönen, Petri; Koskinen, Patrik; Holm, Liisa; Chen, Ching-Tai; Hsu, Wen-Lian; Bryson, Kevin; Cozzetto, Domenico; Minneci, Federico; Jones, David T; Chapman, Samuel; Bkc, Dukka; Khan, Ishita K; Kihara, Daisuke; Ofer, Dan; Rappoport, Nadav; Stern, Amos; Cibrian-Uhalte, Elena; Denny, Paul; Foulger, Rebecca E; Hieta, Reija; Legge, Duncan; Lovering, Ruth C; Magrane, Michele; Melidoni, Anna N; Mutowo-Meullenet, Prudence; Pichler, Klemens; Shypitsyna, Aleksandra; Li, Biao; Zakeri, Pooya; ElShal, Sarah; Tranchevent, Léon-Charles; Das, Sayoni; Dawson, Natalie L; Lee, David; Lees, Jonathan G; Sillitoe, Ian; Bhat, Prajwal; Nepusz, Tamás; Romero, Alfonso E; Sasidharan, Rajkumar; Yang, Haixuan; Paccanaro, Alberto; Gillis, Jesse; Sedeño-Cortés, Adriana E; Pavlidis, Paul; Feng, Shou; Cejuela, Juan M; Goldberg, Tatyana; Hamp, Tobias; Richter, Lothar; Salamov, Asaf; Gabaldon, Toni; Marcet-Houben, Marina; Supek, Fran; Gong, Qingtian; Ning, Wei; Zhou, Yuanpeng; Tian, Weidong; Falda, Marco; Fontana, Paolo; Lavezzo, Enrico; Toppo, Stefano; Ferrari, Carlo; Giollo, Manuel; Piovesan, Damiano; Tosatto, Silvio C E; Del Pozo, Angela; Fernández, José M; Maietta, Paolo; Valencia, Alfonso; Tress, Michael L; Benso, Alfredo; Di Carlo, Stefano; Politano, Gianfranco; Savino, Alessandro; Rehman, Hafeez Ur; Re, Matteo; Mesiti, Marco; Valentini, Giorgio; Bargsten, Joachim W; van Dijk, Aalt D J; Gemovic, Branislava; Glisic, Sanja; Perovic, Vladmir; Veljkovic, Veljko; Veljkovic, Nevena; Almeida-E-Silva, Danillo C; Vencio, Ricardo Z N; Sharan, Malvika; Vogel, Jörg; Kansakar, Lakesh; Zhang, Shanshan; Vucetic, Slobodan; Wang, Zheng; Sternberg, Michael J E; Wass, Mark N; Huntley, Rachael P; Martin, Maria J; O'Donovan, Claire; Robinson, Peter N; Moreau, Yves; Tramontano, Anna; Babbitt, Patricia C; Brenner, Steven E; Linial, Michal; Orengo, Christine A; Rost, Burkhard; Greene, Casey S; Mooney, Sean D; Friedberg, Iddo; Radivojac, Predrag

    2016-09-07

    A major bottleneck in our understanding of the molecular underpinnings of life is the assignment of function to proteins. While molecular experiments provide the most reliable annotation of proteins, their relatively low throughput and restricted purview have led to an increasing role for computational function prediction. However, assessing methods for protein function prediction and tracking progress in the field remain challenging. We conducted the second critical assessment of functional annotation (CAFA), a timed challenge to assess computational methods that automatically assign protein function. We evaluated 126 methods from 56 research groups for their ability to predict biological functions using Gene Ontology and gene-disease associations using Human Phenotype Ontology on a set of 3681 proteins from 18 species. CAFA2 featured expanded analysis compared with CAFA1, with regards to data set size, variety, and assessment metrics. To review progress in the field, the analysis compared the best methods from CAFA1 to those of CAFA2. The top-performing methods in CAFA2 outperformed those from CAFA1. This increased accuracy can be attributed to a combination of the growing number of experimental annotations and improved methods for function prediction. The assessment also revealed that the definition of top-performing algorithms is ontology specific, that different performance metrics can be used to probe the nature of accurate predictions, and the relative diversity of predictions in the biological process and human phenotype ontologies. While there was methodological improvement between CAFA1 and CAFA2, the interpretation of results and usefulness of individual methods remain context-dependent.

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

    Science.gov (United States)

    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

  3. Diagnostic needle arthroscopy and the economics of improved diagnostic accuracy: a cost analysis.

    Science.gov (United States)

    Voigt, Jeffrey D; Mosier, Michael; Huber, Bryan

    2014-10-01

    Hundreds of thousands of surgical arthroscopy procedures are performed annually in the United States (US) based on MRI findings. There are situations where these MRI findings are equivocal or indeterminate and because of this clinicians commonly perform the arthroscopy in order not to miss pathology. Recently, a less invasive needle arthroscopy system has been introduced that is commonly performed in the physician office setting and that may help improve the accuracy of diagnostic findings. This in turn may prevent unnecessary follow-on arthroscopy procedures from being performed. The purpose of this analysis is to determine whether the in-office diagnostic needle arthroscopy system can provide cost savings by reducing unnecessary follow on arthroscopy procedures. Data obtained from a recent trial and from a systematic review were used in comparing the accuracy of MRI and VisionScope needle arthroscopy (VSI) with standard arthroscopy (gold standard). The resultant false positive and false negative findings were then used to evaluate the costs of follow-on procedures. These differences were then modeled for the US patient population diagnosed and treated for meniscal knee pathology (most common disorder) to determine if a technology such as VSI could save the US healthcare system money. Data on surgical arthroscopy procedures in the US for meniscal knee pathology were used (calendar year [CY] 2010). The costs of performing diagnostic and surgical arthroscopy procedures (using CY 2013 Medicare reimbursement amounts), costs associated with false negative findings, and the costs for treating associated complications arising from diagnostic and therapeutic arthroscopy procedures were assessed. In patients presenting with medial meniscal pathology (International Classification of Diseases, 9th edition, Clinical Modification [ICD9CM] diagnosis 836.0), VSI in place of MRI (standard of care) resulted in a net cost savings to the US system of US$115-US$177 million (CY 2013

  4. Hybrid Indoor-Based WLAN-WSN Localization Scheme for Improving Accuracy Based on Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Zahid Farid

    2016-01-01

    Full Text Available In indoor environments, WiFi (RSS based localization is sensitive to various indoor fading effects and noise during transmission, which are the main causes of localization errors that affect its accuracy. Keeping in view those fading effects, positioning systems based on a single technology are ineffective in performing accurate localization. For this reason, the trend is toward the use of hybrid positioning systems (combination of two or more wireless technologies in indoor/outdoor localization scenarios for getting better position accuracy. This paper presents a hybrid technique to implement indoor localization that adopts fingerprinting approaches in both WiFi and Wireless Sensor Networks (WSNs. This model exploits machine learning, in particular Artificial Natural Network (ANN techniques, for position calculation. The experimental results show that the proposed hybrid system improved the accuracy, reducing the average distance error to 1.05 m by using ANN. Applying Genetic Algorithm (GA based optimization technique did not incur any further improvement to the accuracy. Compared to the performance of GA optimization, the nonoptimized ANN performed better in terms of accuracy, precision, stability, and computational time. The above results show that the proposed hybrid technique is promising for achieving better accuracy in real-world positioning applications.

  5. Improving the Stability and Accuracy of Power Hardware-in-the-Loop Simulation Using Virtual Impedance Method

    Directory of Open Access Journals (Sweden)

    Xiaoming Zha

    2016-11-01

    Full Text Available Power hardware-in-the-loop (PHIL systems are advanced, real-time platforms for combined software and hardware testing. Two paramount issues in PHIL simulations are the closed-loop stability and simulation accuracy. This paper presents a virtual impedance (VI method for PHIL simulations that improves the simulation’s stability and accuracy. Through the establishment of an impedance model for a PHIL simulation circuit, which is composed of a voltage-source converter and a simple network, the stability and accuracy of the PHIL system are analyzed. Then, the proposed VI method is implemented in a digital real-time simulator and used to correct the combined impedance in the impedance model, achieving higher stability and accuracy of the results. The validity of the VI method is verified through the PHIL simulation of two typical PHIL examples.

  6. Ammonium improves elution of fixed dried blood spots without affecting immunofluorescence assay quality.

    Science.gov (United States)

    Borremans, Benny

    2014-04-01

    To solve the problem of fixed dried blood spot elution without damaging IgG antibodies. The minimum effective concentration of liquid ammonium (NH3 ) in a PBS solution, which was found to elute fixed blood, was determined. By using a dilution series, the effects of NH3 on IgG antibody quality were assessed using immunofluorescence assays. The minimum effective concentration of 0.2% NH3 has no detectable effects on IgG quality. Ammonium greatly improves blood elution from fixed DBS while maintaining IgG antibody quality. These results are encouraging and provide a basis for further testing of the efficacy of ammonium in different situations as well as its effect on other compounds. © 2014 John Wiley & Sons Ltd.

  7. [Application of the improved MTT assay in predicting the intrinsic drug resistance of liver cancer].

    Science.gov (United States)

    Li, Qian-yu; Wang, Yi; Yin, Zheng-feng; Wu, Meng-chao

    2007-01-30

    To investigate the role of the improved MTT assay in prediction of intrinsic drug resistance of liver cancer. The convenient MTT colorimetry was innovated to test the effects of 4'-epi-adriamycin (E-ADM), carboplatin (CBP), and 5-Fluorouracil(5-Fu), used alone or in combination, on 30 specimens of primary liver cancer without chemotherapy. All of the 30 paraffin-embedded tissues were assembled in a microarray. The used terminal concentrations of drugs were one twentieth those of the plasma peak concentrations calculated by using the liver cancer cells of the line SMMC-7721. The expression of P-glycoprotein (P-gp), multidrug resistant protein (MRP)-3, lung resistance-related protein (LRP), glutathione S-transferase (GST)-pi, and 2 kinds of cyclin-related protein: p16(INK4a) and p21WAF1, were detected by immunohistochemistry. Sixteen of the 30 specimens (53.3%) were drug-resistant and 14 of the 30 specimens (46.7%) were drug-sensitive. The sequence of drug -sensitivity was in the order of combination chemotherapy, E-ADM, 5-Fu, and CBP. The positive rate of P-gp in the drug-resistant group was 56.3%, significantly higher than that of the drug-sensitive group (14.3%, P improved MTT assay has been developed that is more scientific and worth spreading clinically. Intrinsic drug resistance of liver cancer is popular. P-gp is a good predictive marker in intrinsic drug resistance of liver cancer.

  8. Improving accuracy in the MPM method using a null space filter

    Science.gov (United States)

    Gritton, Chris; Berzins, Martin

    2017-01-01

    The material point method (MPM) has been very successful in providing solutions to many challenging problems involving large deformations. Nevertheless there are some important issues that remain to be resolved with regard to its analysis. One key challenge applies to both MPM and particle-in-cell (PIC) methods and arises from the difference between the number of particles and the number of the nodal grid points to which the particles are mapped. This difference between the number of particles and the number of grid points gives rise to a non-trivial null space of the linear operator that maps particle values onto nodal grid point values. In other words, there are non-zero particle values that when mapped to the grid point nodes result in a zero value there. Moreover, when the nodal values at the grid points are mapped back to particles, part of those particle values may be in that same null space. Given positive mapping weights from particles to nodes such null space values are oscillatory in nature. While this problem has been observed almost since the beginning of PIC methods there are still elements of it that are problematical today as well as methods that transcend it. The null space may be viewed as being connected to the ringing instability identified by Brackbill for PIC methods. It will be shown that it is possible to remove these null space values from the solution using a null space filter. This filter improves the accuracy of the MPM methods using an approach that is based upon a local singular value decomposition (SVD) calculation. This local SVD approach is compared against the global SVD approach previously considered by the authors and to a recent MPM method by Zhang and colleagues.

  9. Integration of reflectance confocal microscopy in sequential dermoscopy follow-up improves melanoma detection accuracy.

    Science.gov (United States)

    Stanganelli, I; Longo, C; Mazzoni, L; Magi, S; Medri, M; Lanzanova, G; Farnetani, F; Pellacani, G

    2015-02-01

    Successful treatment of melanoma depends on early diagnosis, but its varied clinical presentation means that no single noninvasive method or criterion can provide reliable detection in all cases. To determine whether combining sequential dermoscopy imaging with reflectance confocal microscopy (RCM) can improve melanoma detection and reduce the burden of unnecessary excisions. We conducted a retrospective study with median follow-up of 25 months. We included equivocal pigmented lesions that lacked clear dermoscopy criteria for melanoma at baseline but were excised subsequently because of changes during digital monitoring. RCM imaging was performed before excision. Main melanoma dermoscopy features, seven-point checklist score at baseline, and changes in structure and/or colour, and development of new melanoma-specific criteria at follow-up (scored as major, moderate or minor) were considered. Main melanoma RCM criteria were evaluated and diagnosis was made. Histopathological diagnosis was the reference standard for defining parameter frequency and diagnostic accuracy. Seventy lesions were included. Major changes were more frequently correlated with melanoma diagnosis, although one-third (four of 12) of melanomas showed moderate or minor changes. Cytological atypia and architectural disarrangement on RCM were correlated with melanoma diagnosis. A correct melanoma diagnosis was achieved with RCM in almost all cases (11 of 12, 92%). Referring for excision only those lesions with RCM-positive features and/or presenting major changes at digital dermoscopy follow-up, theoretically 27 of 58 naevi could be saved from surgery. Integration of RCM in the clinical and instrumental strategy for managing difficult pigmented lesions provided additional diagnostic information useful in the decision-making process. © 2014 British Association of Dermatologists.

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

    Directory of Open Access Journals (Sweden)

    Kyuman Lee

    2016-08-01

    Full Text Available 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

  11. Multi-scale hippocampal parcellation improves atlas-based segmentation accuracy

    Science.gov (United States)

    Plassard, Andrew J.; McHugo, Maureen; Heckers, Stephan; Landman, Bennett A.

    2017-02-01

    Known for its distinct role in memory, the hippocampus is one of the most studied regions of the brain. Recent advances in magnetic resonance imaging have allowed for high-contrast, reproducible imaging of the hippocampus. Typically, a trained rater takes 45 minutes to manually trace the hippocampus and delineate the anterior from the posterior segment at millimeter resolution. As a result, there has been a significant desire for automated and robust segmentation of the hippocampus. In this work we use a population of 195 atlases based on T1-weighted MR images with the left and right hippocampus delineated into the head and body. We initialize the multi-atlas segmentation to a region directly around each lateralized hippocampus to both speed up and improve the accuracy of registration. This initialization allows for incorporation of nearly 200 atlases, an accomplishment which would typically involve hundreds of hours of computation per target image. The proposed segmentation results in a Dice similiarity coefficient over 0.9 for the full hippocampus. This result outperforms a multi-atlas segmentation using the BrainCOLOR atlases (Dice 0.85) and FreeSurfer (Dice 0.75). Furthermore, the head and body delineation resulted in a Dice coefficient over 0.87 for both structures. The head and body volume measurements also show high reproducibility on the Kirby 21 reproducibility population (R2 greater than 0.95, p < 0.05 for all structures). This work signifies the first result in an ongoing work to develop a robust tool for measurement of the hippocampus and other temporal lobe structures.

  12. Improved reliability, accuracy and quality in automated NMR structure calculation with ARIA

    Energy Technology Data Exchange (ETDEWEB)

    Mareuil, Fabien [Institut Pasteur, Cellule d' Informatique pour la Biologie (France); Malliavin, Thérèse E.; Nilges, Michael; Bardiaux, Benjamin, E-mail: bardiaux@pasteur.fr [Institut Pasteur, Unité de Bioinformatique Structurale, CNRS UMR 3528 (France)

    2015-08-15

    In biological NMR, assignment of NOE cross-peaks and calculation of atomic conformations are critical steps in the determination of reliable high-resolution structures. ARIA is an automated approach that performs NOE assignment and structure calculation in a concomitant manner in an iterative procedure. The log-harmonic shape for distance restraint potential and the Bayesian weighting of distance restraints, recently introduced in ARIA, were shown to significantly improve the quality and the accuracy of determined structures. In this paper, we propose two modifications of the ARIA protocol: (1) the softening of the force field together with adapted hydrogen radii, which is meaningful in the context of the log-harmonic potential with Bayesian weighting, (2) a procedure that automatically adjusts the violation tolerance used in the selection of active restraints, based on the fitting of the structure to the input data sets. The new ARIA protocols were fine-tuned on a set of eight protein targets from the CASD–NMR initiative. As a result, the convergence problems previously observed for some targets was resolved and the obtained structures exhibited better quality. In addition, the new ARIA protocols were applied for the structure calculation of ten new CASD–NMR targets in a blind fashion, i.e. without knowing the actual solution. Even though optimisation of parameters and pre-filtering of unrefined NOE peak lists were necessary for half of the targets, ARIA consistently and reliably determined very precise and highly accurate structures for all cases. In the context of integrative structural biology, an increasing number of experimental methods are used that produce distance data for the determination of 3D structures of macromolecules, stressing the importance of methods that successfully make use of ambiguous and noisy distance data.

  13. Improvement in the accuracy of flux measurement of radio sources by exploiting an arithmetic pattern in photon bunching noise

    Science.gov (United States)

    Lieu, Richard

    2018-01-01

    A hierarchy of statistics of increasing sophistication and accuracy is proposed, to exploit an interesting and fundamental arithmetic structure in the photon bunching noise of incoherent light of large photon occupation number, with the purpose of suppressing the noise and rendering a more reliable and unbiased measurement of the light intensity. The method does not require any new hardware, rather it operates at the software level, with the help of high precision computers, to reprocess the intensity time series of the incident light to create a new series with smaller bunching noise coherence length. The ultimate accuracy improvement of this method of flux measurement is limited by the timing resolution of the detector and the photon occupation number of the beam (the higher the photon number the better the performance). The principal application is accuracy improvement in the bolometric flux measurement of a radio source.

  14. Improvement in clinical step and shoot intensity modulated radiation therapy delivery accuracy on an integrated linear accelerator control system.

    Science.gov (United States)

    Agnew, C E; Irvine, D M; Hounsell, A R; McGarry, C K

    2014-01-01

    The dose delivery accuracy of 30 clinical step and shoot intensity modulated radiation therapy plans was investigated using the single integrated multileaf collimator controller of the Varian Truebeam linear accelerator (linac) (Varian Medical Systems, Palo Alto, CA) and compared with the dose delivery accuracy on a previous generation Varian 2100CD C-Series linac. Ten prostate, 10 prostate and pelvic node, and 10 head-and-neck cases were investigated in this study. Dose delivery accuracy on each linac was assessed using Farmer ionization chamber point dose measurements, 2-dimensional planar ionization chamber array measurements, and the corresponding Varian dynamic log files. Absolute point dose measurements, fluence delivery accuracy, leaf position accuracy, and the overshoot effect were assessed for each plan. Absolute point dose delivery accuracy increased by 1.5% on the Truebeam compared with the 2100CD linac. No improvement in fluence delivery accuracy between the linacs, at a gamma criterion of 3%/3 mm was measured using the 2-dimensional ionization chamber array, with median (interquartile range) gamma passing rates of 98.99% (97.70%-99.72%) and 99.28% (98.26%-99.75%) for the Truebeam and 2100CD linacs, respectively. Varian log files also showed no improvement in fluence delivery between the linacs at 3%/3 mm, with median gamma passing rates of 99.97% (99.93%-99.99%) and 99.98% (99.94%-100%) for the Truebeam and 2100CD linacs, respectively. However, log files revealed improved leaf position accuracy and fluence delivery at 1%/1 mm criterion on the Truebeam (99.87%; 99.78%-99.94%) compared with the 2100CD linac (97.87%; 91.93%-99.49%). The overshoot effect, characterized on the 2100CD linac, was not observed on the Truebeam. The integrated multileaf collimator controller on the Varian Truebeam improves clinical treatment delivery accuracy of step and shoot intensity modulated radiation therapy fields compared with delivery on a Varian C-series linac. Crown

  15. Improved accuracy of capacitive sensor-based micro-angle measurement with angular-to-linear displacement conversion

    Science.gov (United States)

    Tan, Xinran; Zhu, Fan; Wang, Chao; Shi, Jian; Qi, Xue; Yu, Yang; Yuan, Feng; Tan, Jiubin

    2017-11-01

    This paper presents a capacitive sensor-based micro-angle measurement (CSMAM) method that uses an angular-to-linear displacement conversion to achieve high accuracy. The principal and secondary error components of CSMAMs are modeled and analyzed to reveal their impacts on the measurement accuracy. The theoretical accuracies of six types of commonly used CSMAMs are analyzed to determine the optimum configuration of capacitive sensors for 1D and 2D micro-angle measurements. An angular-to-linear displacement conversion method with a linear motional stage and a hemisphere decoupler is used to eliminate the principal error of CSMAM. Experimental results indicate that the optimized CSMAM can achieve accuracies of 0.157 arc sec and 0.052 arc sec in the ranges of ±900 arc sec and ±300 arc sec, respectively, in the case that the effective length of the rotation arm is 100 mm and the linear displacement measurement accuracy of the capacitive sensor is 2 nm. These results can be used as a reference to further improve CSMAM designs and achieve high accuracy in a large measurement range, for use in a wide range of precision engineering applications including angle metrology, micro- and nano-radian angle generators, beam steering mechanisms, and high-performance precision stages.

  16. Improved accuracy of capacitive sensor-based micro-angle measurement with angular-to-linear displacement conversion.

    Science.gov (United States)

    Tan, Xinran; Zhu, Fan; Wang, Chao; Shi, Jian; Qi, Xue; Yu, Yang; Yuan, Feng; Tan, Jiubin

    2017-11-01

    This paper presents a capacitive sensor-based micro-angle measurement (CSMAM) method that uses an angular-to-linear displacement conversion to achieve high accuracy. The principal and secondary error components of CSMAMs are modeled and analyzed to reveal their impacts on the measurement accuracy. The theoretical accuracies of six types of commonly used CSMAMs are analyzed to determine the optimum configuration of capacitive sensors for 1D and 2D micro-angle measurements. An angular-to-linear displacement conversion method with a linear motional stage and a hemisphere decoupler is used to eliminate the principal error of CSMAM. Experimental results indicate that the optimized CSMAM can achieve accuracies of 0.157 arc sec and 0.052 arc sec in the ranges of ±900 arc sec and ±300 arc sec, respectively, in the case that the effective length of the rotation arm is 100 mm and the linear displacement measurement accuracy of the capacitive sensor is 2 nm. These results can be used as a reference to further improve CSMAM designs and achieve high accuracy in a large measurement range, for use in a wide range of precision engineering applications including angle metrology, micro- and nano-radian angle generators, beam steering mechanisms, and high-performance precision stages.

  17. The Role of Incidental Unfocused Prompts and Recasts in Improving English as a Foreign Language Learners' Accuracy

    Science.gov (United States)

    Rahimi, Muhammad; Zhang, Lawrence Jun

    2016-01-01

    This study was designed to investigate the effects of incidental unfocused prompts and recasts on improving English as a foreign language (EFL) learners' grammatical accuracy as measured in students' oral interviews and the Test of English as a Foreign Language (TOEFL) grammar test. The design of the study was quasi-experimental with pre-tests,…

  18. A simulated Linear Mixture Model to Improve Classification Accuracy of Satellite Data Utilizing Degradation of Atmospheric Effect

    Directory of Open Access Journals (Sweden)

    WIDAD Elmahboub

    2005-02-01

    Full Text Available Researchers in remote sensing have attempted to increase the accuracy of land cover information extracted from remotely sensed imagery. Factors that influence the supervised and unsupervised classification accuracy are the presence of atmospheric effect and mixed pixel information. A linear mixture simulated model experiment is generated to simulate real world data with known end member spectral sets and class cover proportions (CCP. The CCP were initially generated by a random number generator and normalized to make the sum of the class proportions equal to 1.0 using MATLAB program. Random noise was intentionally added to pixel values using different combinations of noise levels to simulate a real world data set. The atmospheric scattering error is computed for each pixel value for three generated images with SPOT data. Accuracy can either be classified or misclassified. Results portrayed great improvement in classified accuracy, for example, in image 1, misclassified pixels due to atmospheric noise is 41 %. Subsequent to the degradation of atmospheric effect, the misclassified pixels were reduced to 4 %. We can conclude that accuracy of classification can be improved by degradation of atmospheric noise.

  19. Incorporation of Inter-Subject Information to Improve the Accuracy of Subject-Specific P300 Classifiers.

    Science.gov (United States)

    Xu, Minpeng; Liu, Jing; Chen, Long; Qi, Hongzhi; He, Feng; Zhou, Peng; Wan, Baikun; Ming, Dong

    2016-05-01

    Although the inter-subject information has been demonstrated to be effective for a rapid calibration of the P300-based brain-computer interface (BCI), it has never been comprehensively tested to find if the incorporation of heterogeneous data could enhance the accuracy. This study aims to improve the subject-specific P300 classifier by adding other subject's data. A classifier calibration strategy, weighted ensemble learning generic information (WELGI), was developed, in which elementary classifiers were constructed by using both the intra- and inter-subject information and then integrated into a strong classifier with a weight assessment. 55 subjects were recruited to spell 20 characters offline using the conventional P300-based BCI, i.e. the P300-speller. Four different metrics, the P300 accuracy and precision, the round accuracy, and the character accuracy, were performed for a comprehensive investigation. The results revealed that the classifier constructed on the training dataset in combination with adding other subject's data was significantly superior to that without the inter-subject information. Therefore, the WELGI is an effective classifier calibration strategy which uses the inter-subject information to improve the accuracy of subject-specific P300 classifiers, and could also be applied to other BCI paradigms.

  20. Simulated single-cycle kinetics improves the design of surface plasmon resonance assays.

    Science.gov (United States)

    Palau, William; Di Primo, Carmelo

    2013-09-30

    Instruments based on the surface plasmon resonance (SPR) principle are widely used to monitor in real time molecular interactions between a partner, immobilized on a sensor chip surface and another one injected in a continuous flow of buffer. In a classical SPR experiment, several cycles of binding and regeneration of the surface are performed in order to determine the rate and the equilibrium constants of the reaction. In 2006, Karlsson and co-workers introduced a new method named single-cycle kinetics (SCK) to perform SPR assays. The method consists in injecting sequentially increasing concentrations of the partner in solution, with only one regeneration step performed at the end of the complete binding cycle. A 10 base-pair DNA duplex was characterized kinetically to show how simulated sensorgrams generated by the BiaEvaluation software provided by Biacore™ could really improve the design of SPR assays performed with the SCK method. The DNA duplex was investigated at three temperatures, 10, 20 and 30 °C, to analyze fast and slow rate constants. The results show that after a short obligatory preliminary experiment, simulations provide users with the best experimental conditions to be used, in particular, the maximum concentration used to reach saturation, the dilution factor for the serial dilutions of the sample injected and the duration of the dissociation and association phases. The use of simulated single-cycle kinetics saves time and reduces sample consumption. Simulations can also be used to design SPR experiments with ternary complexes. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Assay performance improved, but which "scorecard" designation for Vitros Troponin I?

    Science.gov (United States)

    Zaninotto, M; Vernocchi, A; Di Serio, F; Viloria, M Del Mar; Hurtado, Josè M; Perez-Guerrero, J J; Plebani, M

    2012-04-11

    Since cardiac troponins assay technology should comply with the recommendations of scientific societies (i.e. imprecision (10%) at the 99th percentile value observed in healthy subjects being the analytical qualifying aspect), the aim of the present study was to evaluate whether an improved troponin assay (Vitros Troponin I ES) provides data that meet the "guideline acceptable"criteria recently defined in a proposed scorecard. Vitros Troponin I ES, an enhanced chemiluminescence immunoassay, was evaluated in a multicenter study considering: limit of blank (LOB, 60 replicates of 0 calibrators), limit of detection (LOD, 12 measurements for each of 5 serum pools), precision, linearity using control materials and serum plasma pool; matrix samples study matching serum and lithium-heparin plasma (n=107 hospitalized patients); the 99th percentile limit in serum samples from 500 healthy Caucasian donors. LOB and LOD, 0.0029 μg/L and 0.0030 μg/L respectively; coefficients of variation (total CV%), obtained by running 3 levels of control materials and 10 serum pools, from 15.2% (x(-)=0.014 μg/L) to 2.0% (x(-)=5.324 μg/L); method, linear up to 70 μg/L. No significant differences were found between serum and lithium-heparin matched sample (p=0.48) values; 99th percentile limit of cTnI distribution in healthy donors, 0.021 μg/L. Since its analytical reliability meets the proposed performance and scorecard requirements, the Vitros TropI method can be considered "contemporary" and "guideline acceptable". Copyright © 2012 Elsevier B.V. All rights reserved.

  2. High Affinity Mannotetraose as an Alternative to Dextran in ConA Based Fluorescent Affinity Glucose Assay Due to Improved FRET Efficiency.

    Science.gov (United States)

    Locke, Andrea K; Cummins, Brian M; Coté, Gerard L

    2016-05-27

    Diabetes mellitus affects millions of people worldwide and requires that individuals tightly self-regulate their blood glucose levels to minimize the associated secondary complications. Continuous monitoring devices potentially offer patients a long-term means to tightly monitor their glucose levels. In recent years, fluorescent affinity sensors based on lectins (e.g., Concanavalin A (ConA)) have been implemented in such devices. Traditionally, these sensors pair the lectin with a multivalent ligand, like dextran, in order to develop a competitive binding assay that changes its fluorescent properties in response to the surrounding glucose concentrations. This work introduces a new type of fluorescent ligand for FRET-based assays in an attempt to improve the sensitivity of such assays. This ligand is rationally designed to present a core trimannose structure and a donor fluorophore in close proximity to one another. This design decreases the distance between the FRET donor and the FRET acceptors on ConA to maximize the FRET efficiency upon binding of the ligand to ConA. This work specifically compares the FRET efficiency and sensitivity of this new competing ligand with a traditional dextran ligand, showing that the new ligand has improved characteristics. This work also tested the long-term thermal stability of the assay based on this new competing ligand and displayed a MARD of less than 10% across the physiological range of glucose after 30 days incubation at 37 °C. Ultimately, this new type of fluorescent ligand has the potential to significantly improve the accuracy of continuous glucose monitoring devices based on the competitive binding sensing approach.

  3. Improving accuracy of cell and chromophore concentration measurements using optical density.

    Science.gov (United States)

    Myers, John A; Curtis, Brandon S; Curtis, Wayne R

    2013-04-22

    UV-vis spectrophotometric optical density (OD) is the most commonly-used technique for estimating chromophore formation and cell concentration in liquid culture. OD wavelength is often chosen with little thought given to its effect on the quality of the measurement. Analysis of the contributions of absorption and scattering to the measured optical density provides a basis for understanding variability among spectrophotometers and enables a quantitative evaluation of the applicability of the Beer-Lambert law. This provides a rational approach for improving the accuracy of OD measurements used as a proxy for direct dry weight (DW), cell count, and pigment levels. For pigmented organisms, the choice of OD wavelength presents a tradeoff between the robustness and the sensitivity of the measurement. The OD at a robust wavelength is primarily the result of light scattering and does not vary with culture conditions; whereas, the OD at a sensitive wavelength is additionally dependent on light absorption by the organism's pigments. Suitably robust and sensitive wavelengths are identified for a wide range of organisms by comparing their spectra to the true absorption spectra of dyes. The relative scattering contribution can be reduced either by measurement at higher OD, or by the addition of bovine serum albumin. Reduction of scattering or correlation with off-peak light attenuation provides for more accurate assessment of chromophore levels within cells. Conversion factors between DW, OD, and colony-forming unit density are tabulated for 17 diverse organisms to illustrate the scope of variability of these correlations. Finally, an inexpensive short pathlength LED-based flow cell is demonstrated for the online monitoring of growth in a bioreactor at culture concentrations greater than 5 grams dry weight per liter which would otherwise require off-line dilutions to obtain non-saturated OD measurements. OD is most accurate as a time-saving proxy measurement for biomass

  4. Tools to improve the accuracy of kidney stone sizing with ultrasound.

    Science.gov (United States)

    Dunmire, Barbrina; Lee, Franklin C; Hsi, Ryan S; Cunitz, Bryan W; Paun, Marla; Bailey, Michael R; Sorensen, Mathew D; Harper, Jonathan D

    2015-02-01

    Ultrasound (US) overestimates stone size when compared with CT. The purpose of this work was to evaluate the overestimation of stone size with US in an in vitro water bath model and investigate methods to reduce overestimation. Ten human stones (3-12 mm) were measured using B-mode (brightness mode) US by a sonographer blinded to the true stone size. Images were captured and compared using both a commercial US machine and software-based research US device. Image gain was adjusted between moderate and high stone intensities, and the transducer-to-stone depth was varied from 6 to 10 cm. A computerized stone-sizing program was developed to outline the stone width based on a grayscale intensity threshold. Overestimation with the commercial device increased with both gain and depth. Average overestimation at moderate and high gain was 1.9±0.8 and 2.1±0.9 mm, respectively (p=0.6). Overestimation increased an average of 22% with an every 2-cm increase in depth (p=0.02). Overestimation using the research device was 1.5±0.9 mm and did not vary with depth (p=0.28). Overestimation could be reduced to 0.02±1.1 mm (p<0.001) with the computerized stone-sizing program. However, a standardized threshold consistent across depth, system, or system settings could not be resolved. Stone size is consistently overestimated with US. Overestimation increased with increasing depth and gain using the commercial machine. Overestimation was reduced and did not vary with depth, using the software-based US device. The computerized stone-sizing program shows the potential to reduce overestimation by implementing a grayscale intensity threshold for defining the stone size. More work is needed to standardize the approach, but if successful, such an approach could significantly improve stone-sizing accuracy and lead to automation of stone sizing.

  5. Improving The Accuracy Of Bluetooth Based Travel Time Estimation Using Low-Level Sensor Data

    DEFF Research Database (Denmark)

    Araghi, Bahar Namaki; Tørholm Christensen, Lars; Krishnan, Rajesh

    2013-01-01

    triggered by a single device. This could lead to location ambiguity and reduced accuracy of travel time estimation. Therefore, the accuracy of travel time estimations by Bluetooth Technology (BT) depends upon how location ambiguity is handled by the estimation method. The issue of multiple detection events...... in the context of travel time estimation by BT has been considered by various researchers. However, treatment of this issue has remained simplistic so far. Most previous studies simply used the first detection event (Enter-Enter) as the best estimate. No systematic analysis for exploring the most accurate method...... of estimating travel time using multiple detection events has been conducted. In this study different aspects of BT detection zone, including size and its impact on the accuracy of travel time estimation, are discussed. Moreover, four alternative methods are applied; namely, Enter-Enter, Leave-Leave, Peak...

  6. Comparative accuracy of the REBA MTB MDR and Hain MTBDRplus line probe assays for the detection of multidrug-resistant tuberculosis: A multicenter, non-inferiority study.

    Science.gov (United States)

    Havumaki, Joshua; Hillemann, Doris; Ismail, Nazir; Omar, Shaheed Vally; Georghiou, Sophia B; Schumacher, Samuel G; Boehme, Catharina; Denkinger, Claudia M

    2017-01-01

    Despite recent diagnostic advances, the majority of multidrug-resistant tuberculosis (MDR-TB) cases remain undiagnosed. Line probes assays (LiPAs) hold great promise to curb the spread of MDR-TB as they can rapidly detect MDR-TB even when laboratory infrastructure is limited, yet few of these assays are currently widely available or supported by World Health Organization (WHO) policy. The aim of this prospective, blinded, non-inferiority study was to compare the performance of YD Diagnostics REBA MTB MDR LiPA (YD) to the WHO-endorsed Hain MTBDRplus V1 LiPA (Hain V1) for the detection of rifampicin and isoniazid resistance. In phase 1, YD and Hain V1 diagnostic performance was assessed with selected culture isolates and results were compared to phenotypic drug susceptibility testing (DST) results and targeted sequencing data. In phase 2, both assays were tested on processed sputum samples and results were compared to phenotypic DST results. In phase 1, YD did not achieve non-inferiority to Hain V1. For isoniazid resistance detection, Hain V1 had a sensitivity of 89% (95%CI 83.8-93%) and specificity of 99.4% (95%CI 96.9-100%). While YD had a similar sensitivity of 92% (95%CI 87.3-95.4%), the specificity was inferior at 92.6% (95%CI 87.6-96%). For rifampicin resistance detection, Hain V1 had a sensitivity of 90.2% (95%CI 84.8-94.2%) and specificity of 98.5% (95%CI 95.7-99.7%) while YD had an inferior sensitivity of 72.4% (95%CI 65.1-78.9%) and a comparable specificity of 98% (95%CI 95-99.5%). Similar results were observed in phase 2. For MDR-TB detection, the sensitivity and specificity of Hain V1 was 93.4% (95%CI 88.2-96.2%) and 96.2% (95%CI 88.2-96.8%), respectively, compared to 75.7% (95%CI 68-82.2%) and 92% (95%CI 88.2-94.9%) for YD. YD did not achieve non-inferiority with Hain V1. Further improvements and repeat evaluation of YD is necessary prior to recommending its use for clinical settings.

  7. Exploiting Deep Matching and SAR Data for the Geo-Localization Accuracy Improvement of Optical Satellite Images

    Directory of Open Access Journals (Sweden)

    Nina Merkle

    2017-06-01

    Full Text Available Improving the geo-localization of optical satellite images is an important pre-processing step for many remote sensing tasks like monitoring by image time series or scene analysis after sudden events. These tasks require geo-referenced and precisely co-registered multi-sensor data. Images captured by the high resolution synthetic aperture radar (SAR satellite TerraSAR-X exhibit an absolute geo-location accuracy within a few decimeters. These images represent therefore a reliable source to improve the geo-location accuracy of optical images, which is in the order of tens of meters. In this paper, a deep learning-based approach for the geo-localization accuracy improvement of optical satellite images through SAR reference data is investigated. Image registration between SAR and optical images requires few, but accurate and reliable matching points. These are derived from a Siamese neural network. The network is trained using TerraSAR-X and PRISM image pairs covering greater urban areas spread over Europe, in order to learn the two-dimensional spatial shifts between optical and SAR image patches. Results confirm that accurate and reliable matching points can be generated with higher matching accuracy and precision with respect to state-of-the-art approaches.

  8. Bureau of Indian Affairs Schools: New Facilities Management Information System Promising, but Improved Data Accuracy Needed.

    Science.gov (United States)

    General Accounting Office, Washington, DC.

    A General Accounting Office (GAO) study evaluated the Bureau of Indian Affairs' (BIA) new facilities management information system (FMIS). Specifically, the study examined whether the new FMIS addresses the old system's weaknesses and meets BIA's management needs, whether BIA has finished validating the accuracy of data transferred from the old…

  9. Can Providing Rubrics for Writing Tasks Improve Developing Writers' Calibration Accuracy?

    Science.gov (United States)

    Hawthorne, Katrice A.; Bol, Linda; Pribesh, Shana

    2017-01-01

    Rubric-referenced calibration and the interaction between writing achievement and calibration, a measure of the relationship between one's performance and the accuracy of one's judgments, were investigated. Undergraduate students (N = 596) were assigned to one of three calibration conditions: (a) global, (b) global and general criteria, or (c)…

  10. Knowing What You Know: Improving Metacomprehension and Calibration Accuracy in Digital Text

    Science.gov (United States)

    Reid, Alan J.; Morrison, Gary R.; Bol, Linda

    2017-01-01

    This paper presents results from an experimental study that examined embedded strategy prompts in digital text and their effects on calibration and metacomprehension accuracies. A sample population of 80 college undergraduates read a digital expository text on the basics of photography. The most robust treatment (mixed) read the text, generated a…

  11. Improving Accuracy of River Flow Forecasting Using LSSVR with Gravitational Search Algorithm

    Directory of Open Access Journals (Sweden)

    Rana Muhammad Adnan

    2017-01-01

    Full Text Available River flow prediction is essential in many applications of water resources planning and management. In this paper, the accuracy of multivariate adaptive regression splines (MARS, model 5 regression tree (M5RT, and conventional multiple linear regression (CMLR is compared with a hybrid least square support vector regression-gravitational search algorithm (HLGSA in predicting monthly river flows. In the first part of the study, all three regression methods were compared with each other in predicting river flows of each basin. It was found that the HLGSA method performed better than the MARS, M5RT, and CMLR in river flow prediction. The effect of log transformation on prediction accuracy of the regression methods was also examined in the second part of the study. Log transformation of the river flow data significantly increased the prediction accuracy of all regression methods. It was also found that log HLGSA (LHLSGA performed better than the other regression methods. In the third part of the study, the accuracy of the LHLGSA and HLGSA methods was examined in river flow estimation using nearby river flow data. On the basis of results of all applications, it was found that LHLGSA and HLGSA could be successfully used in prediction and estimation of river flow.

  12. Conjugate Fabry-Perot cavity pair for improved astro-comb accuracy.

    Science.gov (United States)

    Li, Chih-Hao; Chang, Guoqing; Glenday, Alexander G; Langellier, Nicholas; Zibrov, Alexander; Phillips, David F; Kärtner, Franz X; Szentgyorgyi, Andrew; Walsworth, Ronald L

    2012-08-01

    We propose a new astro-comb mode-filtering scheme composed of two Fabry-Perot cavities (coined "conjugate Fabry-Perot cavity pair"). Simulations indicate that this new filtering scheme makes the accuracy of astro-comb spectral lines more robust against systematic errors induced by nonlinear processes associated with power-amplifying and spectral-broadening optical fibers.

  13. A rapid, automated VWF ristocetin cofactor activity assay improves reliability in the diagnosis of Von Willebrand disease.

    Science.gov (United States)

    Bowyer, Annette E; Shepherd, Fiona; Kitchen, Stephen; Makris, Michael

    2011-04-01

    The effective diagnosis and monitoring of Von Willebrand Disease (VWD) requires an accurate assessment of ristocetin co-factor activity (VWF:RCo). Current methodologies include automated platelet aggregometry and manual visual agglutination both of which are laborious to perform and notoriously subject to a high degree of inter and intra assay variation. We have evaluated an automated VWF:RCo assay (BC Von Willebrand Reagent, Siemens, Marberg, Germany) for use on the Sysmex CS2100i analyser (Milton Keynes, UK) and retrospectively compared the results with an in-house manual visual agglutination assay and VWF antigen (Siemens) in normal subjects and in 53 patients with various types of VWD and 23 patients following VWF therapeutic treatment. The intra and interassay CV was improved with the automated assay (2.3% and 3.8% respectively) compared to 7% with the manual VWF:RCo assay. Good correlation was found between the two assays (r=0.91) in 53 patients with VWD. The mean manual VWF:RCo was 0.25IU/ml and mean automated VWF:RCo was 0.27IU/ml. A comparable increase in VWF:RCo following treatment, mostly with Desmopressin, was found in 13 patients with type 1 VWD (mean 3.9 fold increase with manual VWF:RCo and 3.1 fold with the automated VWF:RCo). In 13 patients with type 2 or 3 VWD following treatment mostly with concentrate , a higher increase was found with the automated VWF:RCo assay than the manual assay (mean 11.9 fold manually and mean 20.3 automated). The automated VWF:RCo assay shows enhanced precision and analysis time in this difficult and time consuming laboratory test and its introduction should greatly improve the reliability of VWF testing. Copyright © 2010. Published by Elsevier Ltd.

  14. Improved PCR-Based Detection of Soil Transmitted Helminth Infections Using a Next-Generation Sequencing Approach to Assay Design

    Science.gov (United States)

    Pilotte, Nils; Papaiakovou, Marina; Grant, Jessica R.; Bierwert, Lou Ann; Llewellyn, Stacey; McCarthy, James S.; Williams, Steven A.

    2016-01-01

    Background The soil transmitted helminths are a group of parasitic worms responsible for extensive morbidity in many of the world’s most economically depressed locations. With growing emphasis on disease mapping and eradication, the availability of accurate and cost-effective diagnostic measures is of paramount importance to global control and elimination efforts. While real-time PCR-based molecular detection assays have shown great promise, to date, these assays have utilized sub-optimal targets. By performing next-generation sequencing-based repeat analyses, we have identified high copy-number, non-coding DNA sequences from a series of soil transmitted pathogens. We have used these repetitive DNA elements as targets in the development of novel, multi-parallel, PCR-based diagnostic assays. Methodology/Principal Findings Utilizing next-generation sequencing and the Galaxy-based RepeatExplorer web server, we performed repeat DNA analysis on five species of soil transmitted helminths (Necator americanus, Ancylostoma duodenale, Trichuris trichiura, Ascaris lumbricoides, and Strongyloides stercoralis). Employing high copy-number, non-coding repeat DNA sequences as targets, novel real-time PCR assays were designed, and assays were tested against established molecular detection methods. Each assay provided consistent detection of genomic DNA at quantities of 2 fg or less, demonstrated species-specificity, and showed an improved limit of detection over the existing, proven PCR-based assay. Conclusions/Significance The utilization of next-generation sequencing-based repeat DNA analysis methodologies for the identification of molecular diagnostic targets has the ability to improve assay species-specificity and limits of detection. By exploiting such high copy-number repeat sequences, the assays described here will facilitate soil transmitted helminth diagnostic efforts. We recommend similar analyses when designing PCR-based diagnostic tests for the detection of other

  15. Improved PCR-Based Detection of Soil Transmitted Helminth Infections Using a Next-Generation Sequencing Approach to Assay Design.

    Science.gov (United States)

    Pilotte, Nils; Papaiakovou, Marina; Grant, Jessica R; Bierwert, Lou Ann; Llewellyn, Stacey; McCarthy, James S; Williams, Steven A

    2016-03-01

    The soil transmitted helminths are a group of parasitic worms responsible for extensive morbidity in many of the world's most economically depressed locations. With growing emphasis on disease mapping and eradication, the availability of accurate and cost-effective diagnostic measures is of paramount importance to global control and elimination efforts. While real-time PCR-based molecular detection assays have shown great promise, to date, these assays have utilized sub-optimal targets. By performing next-generation sequencing-based repeat analyses, we have identified high copy-number, non-coding DNA sequences from a series of soil transmitted pathogens. We have used these repetitive DNA elements as targets in the development of novel, multi-parallel, PCR-based diagnostic assays. Utilizing next-generation sequencing and the Galaxy-based RepeatExplorer web server, we performed repeat DNA analysis on five species of soil transmitted helminths (Necator americanus, Ancylostoma duodenale, Trichuris trichiura, Ascaris lumbricoides, and Strongyloides stercoralis). Employing high copy-number, non-coding repeat DNA sequences as targets, novel real-time PCR assays were designed, and assays were tested against established molecular detection methods. Each assay provided consistent detection of genomic DNA at quantities of 2 fg or less, demonstrated species-specificity, and showed an improved limit of detection over the existing, proven PCR-based assay. The utilization of next-generation sequencing-based repeat DNA analysis methodologies for the identification of molecular diagnostic targets has the ability to improve assay species-specificity and limits of detection. By exploiting such high copy-number repeat sequences, the assays described here will facilitate soil transmitted helminth diagnostic efforts. We recommend similar analyses when designing PCR-based diagnostic tests for the detection of other eukaryotic pathogens.

  16. Improved PCR-Based Detection of Soil Transmitted Helminth Infections Using a Next-Generation Sequencing Approach to Assay Design.

    Directory of Open Access Journals (Sweden)

    Nils Pilotte

    2016-03-01

    Full Text Available The soil transmitted helminths are a group of parasitic worms responsible for extensive morbidity in many of the world's most economically depressed locations. With growing emphasis on disease mapping and eradication, the availability of accurate and cost-effective diagnostic measures is of paramount importance to global control and elimination efforts. While real-time PCR-based molecular detection assays have shown great promise, to date, these assays have utilized sub-optimal targets. By performing next-generation sequencing-based repeat analyses, we have identified high copy-number, non-coding DNA sequences from a series of soil transmitted pathogens. We have used these repetitive DNA elements as targets in the development of novel, multi-parallel, PCR-based diagnostic assays.Utilizing next-generation sequencing and the Galaxy-based RepeatExplorer web server, we performed repeat DNA analysis on five species of soil transmitted helminths (Necator americanus, Ancylostoma duodenale, Trichuris trichiura, Ascaris lumbricoides, and Strongyloides stercoralis. Employing high copy-number, non-coding repeat DNA sequences as targets, novel real-time PCR assays were designed, and assays were tested against established molecular detection methods. Each assay provided consistent detection of genomic DNA at quantities of 2 fg or less, demonstrated species-specificity, and showed an improved limit of detection over the existing, proven PCR-based assay.The utilization of next-generation sequencing-based repeat DNA analysis methodologies for the identification of molecular diagnostic targets has the ability to improve assay species-specificity and limits of detection. By exploiting such high copy-number repeat sequences, the assays described here will facilitate soil transmitted helminth diagnostic efforts. We recommend similar analyses when designing PCR-based diagnostic tests for the detection of other eukaryotic pathogens.

  17. An efficient optimization method to improve the measuring accuracy of oxygen saturation by using triangular wave optical signal

    Science.gov (United States)

    Li, Gang; Yu, Yue; Zhang, Cui; Lin, Ling

    2017-09-01

    The oxygen saturation is one of the important parameters to evaluate human health. This paper presents an efficient optimization method that can improve the accuracy of oxygen saturation measurement, which employs an optical frequency division triangular wave signal as the excitation signal to obtain dynamic spectrum and calculate oxygen saturation. In comparison to the traditional method measured RMSE (root mean square error) of SpO2 which is 0.1705, this proposed method significantly reduced the measured RMSE which is 0.0965. It is notable that the accuracy of oxygen saturation measurement has been improved significantly. The method can simplify the circuit and bring down the demand of elements. Furthermore, it has a great reference value on improving the signal to noise ratio of other physiological signals.

  18. Introducing radiology report checklists among residents: adherence rates when suggesting versus requiring their use and early experience in improving accuracy.

    Science.gov (United States)

    Powell, Daniel K; Lin, Eaton; Silberzweig, James E; Kagetsu, Nolan J

    2014-03-01

    To retrospectively compare resident adherence to checklist-style structured reporting for maxillofacial computed tomography (CT) from the emergency department (when required vs. suggested between two programs). To compare radiology resident reporting accuracy before and after introduction of the structured report and assess its ability to decrease the rate of undetected pathology. We introduced a reporting checklist for maxillofacial CT into our dictation software without specific training, requiring it at one program and suggesting it at another. We quantified usage among residents and compared reporting accuracy, before and after counting and categorizing faculty addenda. There was no significant change in resident accuracy in the first few months, with residents acting as their own controls (directly comparing performance with and without the checklist). Adherence to the checklist at program A (where it originated and was required) was 85% of reports compared to 9% of reports at program B (where it was suggested). When using program B as a secondary control, there was no significant difference in resident accuracy with or without using the checklist (comparing different residents using the checklist to those not using the checklist). Our results suggest that there is no automatic value of checklists for improving radiology resident reporting accuracy. They also suggest the importance of focused training, checklist flexibility, and a period of adjustment to a new reporting style. Mandatory checklists were readily adopted by residents but not when simply suggested. Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.

  19. Hybrid Brain–Computer Interface Techniques for Improved Classification Accuracy and Increased Number of Commands: A Review

    Science.gov (United States)

    Hong, Keum-Shik; Khan, Muhammad Jawad

    2017-01-01

    In this article, non-invasive hybrid brain–computer interface (hBCI) technologies for improving classification accuracy and increasing the number of commands are reviewed. Hybridization combining more than two modalities is a new trend in brain imaging and prosthesis control. Electroencephalography (EEG), due to its easy use and fast temporal resolution, is most widely utilized in combination with other brain/non-brain signal acquisition modalities, for instance, functional near infrared spectroscopy (fNIRS), electromyography (EMG), electrooculography (EOG), and eye tracker. Three main purposes of hybridization are to increase the number of control commands, improve classification accuracy and reduce the signal detection time. Currently, such combinations of EEG + fNIRS and EEG + EOG are most commonly employed. Four principal components (i.e., hardware, paradigm, classifiers, and features) relevant to accuracy improvement are discussed. In the case of brain signals, motor imagination/movement tasks are combined with cognitive tasks to increase active brain–computer interface (BCI) accuracy. Active and reactive tasks sometimes are combined: motor imagination with steady-state evoked visual potentials (SSVEP) and motor imagination with P300. In the case of reactive tasks, SSVEP is most widely combined with P300 to increase the number of commands. Passive BCIs, however, are rare. After discussing the hardware and strategies involved in the development of hBCI, the second part examines the approaches used to increase the number of control commands and to enhance classification accuracy. The future prospects and the extension of hBCI in real-time applications for daily life scenarios are provided. PMID:28790910

  20. Hybrid Brain-Computer Interface Techniques for Improved Classification Accuracy and Increased Number of Commands: A Review.

    Science.gov (United States)

    Hong, Keum-Shik; Khan, Muhammad Jawad

    2017-01-01

    In this article, non-invasive hybrid brain-computer interface (hBCI) technologies for improving classification accuracy and increasing the number of commands are reviewed. Hybridization combining more than two modalities is a new trend in brain imaging and prosthesis control. Electroencephalography (EEG), due to its easy use and fast temporal resolution, is most widely utilized in combination with other brain/non-brain signal acquisition modalities, for instance, functional near infrared spectroscopy (fNIRS), electromyography (EMG), electrooculography (EOG), and eye tracker. Three main purposes of hybridization are to increase the number of control commands, improve classification accuracy and reduce the signal detection time. Currently, such combinations of EEG + fNIRS and EEG + EOG are most commonly employed. Four principal components (i.e., hardware, paradigm, classifiers, and features) relevant to accuracy improvement are discussed. In the case of brain signals, motor imagination/movement tasks are combined with cognitive tasks to increase active brain-computer interface (BCI) accuracy. Active and reactive tasks sometimes are combined: motor imagination with steady-state evoked visual potentials (SSVEP) and motor imagination with P300. In the case of reactive tasks, SSVEP is most widely combined with P300 to increase the number of commands. Passive BCIs, however, are rare. After discussing the hardware and strategies involved in the development of hBCI, the second part examines the approaches used to increase the number of control commands and to enhance classification accuracy. The future prospects and the extension of hBCI in real-time applications for daily life scenarios are provided.

  1. Two Simple Rules for Improving the Accuracy of Empiric Treatment of Multidrug-Resistant Urinary Tract Infections.

    Science.gov (United States)

    Linsenmeyer, Katherine; Strymish, Judith; Gupta, Kalpana

    2015-12-01

    The emergence of multidrug-resistant (MDR) uropathogens is making the treatment of urinary tract infections (UTIs) more challenging. We sought to evaluate the accuracy of empiric therapy for MDR UTIs and the utility of prior culture data in improving the accuracy of the therapy chosen. The electronic health records from three U.S. Department of Veterans Affairs facilities were retrospectively reviewed for the treatments used for MDR UTIs over 4 years. An MDR UTI was defined as an infection caused by a uropathogen resistant to three or more classes of drugs and identified by a clinician to require therapy. Previous data on culture results, antimicrobial use, and outcomes were captured from records from inpatient and outpatient settings. Among 126 patient episodes of MDR UTIs, the choices of empiric therapy against the index pathogen were accurate in 66 (52%) episodes. For the 95 patient episodes for which prior microbiologic data were available, when empiric therapy was concordant with the prior microbiologic data, the rate of accuracy of the treatment against the uropathogen improved from 32% to 76% (odds ratio, 6.9; 95% confidence interval, 2.7 to 17.1; P tract (GU)-directed agents (nitrofurantoin or sulfa agents) were equally as likely as broad-spectrum agents to be accurate (P = 0.3). Choosing an agent concordant with previous microbiologic data significantly increased the chance of accuracy of therapy for MDR UTIs, even if the previous uropathogen was a different species. Also, GU-directed or broad-spectrum therapy choices were equally likely to be accurate. The accuracy of empiric therapy could be improved by the use of these simple rules. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  2. Hybrid Brain–Computer Interface Techniques for Improved Classification Accuracy and Increased Number of Commands: A Review

    Directory of Open Access Journals (Sweden)

    Keum-Shik Hong

    2017-07-01

    Full Text Available In this article, non-invasive hybrid brain–computer interface (hBCI technologies for improving classification accuracy and increasing the number of commands are reviewed. Hybridization combining more than two modalities is a new trend in brain imaging and prosthesis control. Electroencephalography (EEG, due to its easy use and fast temporal resolution, is most widely utilized in combination with other brain/non-brain signal acquisition modalities, for instance, functional near infrared spectroscopy (fNIRS, electromyography (EMG, electrooculography (EOG, and eye tracker. Three main purposes of hybridization are to increase the number of control commands, improve classification accuracy and reduce the signal detection time. Currently, such combinations of EEG + fNIRS and EEG + EOG are most commonly employed. Four principal components (i.e., hardware, paradigm, classifiers, and features relevant to accuracy improvement are discussed. In the case of brain signals, motor imagination/movement tasks are combined with cognitive tasks to increase active brain–computer interface (BCI accuracy. Active and reactive tasks sometimes are combined: motor imagination with steady-state evoked visual potentials (SSVEP and motor imagination with P300. In the case of reactive tasks, SSVEP is most widely combined with P300 to increase the number of commands. Passive BCIs, however, are rare. After discussing the hardware and strategies involved in the development of hBCI, the second part examines the approaches used to increase the number of control commands and to enhance classification accuracy. The future prospects and the extension of hBCI in real-time applications for daily life scenarios are provided.

  3. The effect of written corrective feedback on grammatical accuracy of EFL students: An improvement over previous unfocused designs

    Directory of Open Access Journals (Sweden)

    Mobin Khanlarzadeh

    2016-07-01

    Full Text Available The effectiveness of written corrective feedback (WCF in the improvement of language learners' grammatical accuracy has been a topic of interest in SLA studies for the past couple of decades. The present study reports the findings of a three-month study investigating the effect of direct unfocused WCF on the grammatical accuracy of elementary students in an EFL context. The researchers selected two intact classes totaling 33 students, and assigned each to a direct feedback group (n = 16 and a control group (n = 17. The students produced eight pieces of writing (a pretest, three writing tasks along with their revisions, and a posttest from which their grammatical accuracy was obtained. The results indicated that while the experimental group significantly outperformed the control group in the revision of the three writing tasks, no significant difference was found when the two groups produced a new piece of writing after a one-month interval. The study concludes that accuracy improvement caused by unfocused WCF during the revision process does not extend to EFL learners' future writing when no feedback is available, at least at the elementary level.

  4. Evaluating a Bayesian approach to improve accuracy of individual photographic identification methods using ecological distribution data

    Directory of Open Access Journals (Sweden)

    Richard Stafford

    2011-04-01

    Full Text Available Photographic identification of individual organisms can be possible from natural body markings. Data from photo-ID can be used to estimate important ecological and conservation metrics such as population sizes, home ranges or territories. However, poor quality photographs or less well-studied individuals can result in a non-unique ID, potentially confounding several similar looking individuals. Here we present a Bayesian approach that uses known data about previous sightings of individuals at specific sites as priors to help assess the problems of obtaining a non-unique ID. Using a simulation of individuals with different confidence of correct ID we evaluate the accuracy of Bayesian modified (posterior probabilities. However, in most cases, the accuracy of identification decreases. Although this technique is unsuccessful, it does demonstrate the importance of computer simulations in testing such hypotheses in ecology.

  5. Improvement of accuracy of scanning absorption measurement of nuclear DNA content in plants.

    Science.gov (United States)

    Dolezel, J

    1989-01-01

    The effect of optical errors and stain variation on the accuracy of plant Feulgen-DNA absorption cytophotometry was investigated. Optical errors (glare, distributional error, and diffraction) were shown to cause important errors. A correction procedure of DUIJNDAM et al. (1980a) was successfully applied to eliminate them. Stain variation can also lead to serious errors and in case different samples are to be compared the use of an internal standard is imperative. Chicken red blood cells proved to be a reliable standard.

  6. Anodic stripping voltammetry procedure modified for improved accuracy of blood lead analysis.

    Science.gov (United States)

    Roda, S M; Greenland, R D; Bornschein, R L; Hammond, P B

    1988-03-01

    In evaluating the accuracy and reliability of blood lead (PbB) measurements with the Environmental Science Associates Model 3010A Trace Metal Analyzer, intralaboratory comparison demonstrated that use of the operating conditions recommended by the manufacturer resulted in consistently underestimated PbB concentrations less than 400 micrograms/L and overestimated PbB values greater than 400 micrograms/L. At PbB concentrations less than 50 micrograms/L, measured concentrations were often registered as negative results. However, these negative values could be replicated to within +/- 10 micrograms/L, indicating good precision of the method, but obviously not good accuracy. In addition, lower-than-expected lead (Pb) values were measured in samples containing increased concentrations of copper (Cu), such as may occur in pregnant women. We modified the procedure to eliminate these inaccuracies by substituting manual peak-height measurements for reliance on the integrator and digital display of the instrument. We established the accuracy of the modified procedure by using calibration standards previously quantified by isotope dilution-mass spectroscopy. A quality-control program for monitoring PbB analysis is also described.

  7. A modified blood pressure to height ratio improves accuracy for hypertension in childhood.

    Science.gov (United States)

    Mourato, Felipe A; Nadruz, Wilson; Moser, Lucia R D N; de Lima Filho, José L; Mattos, Sandra S

    2015-03-01

    The blood pressure to height ratio (BP:HT) has been proposed as a simple method for identifying children with elevated BP. This procedure shows good accuracy for the screening of hypertension in adolescents but less so in younger children. Our aim in this study was to modify the BP:HT ratio and determine if this change would increase accuracy when measuring hypertension during childhood. BP levels of 4,327 children (aged 5-12 years) were retrospectively obtained from medical charts. The modified ratio (BT:eHT13) was calculated as: BP/(HT + 7 × (13 - age in years)). Receiver operating characteristic curves were used to estimate cutoff points and the accuracy of the conventional and modified ratio to detect prehypertension and hypertension. The prevalences of prehypertension and hypertension were 3.91% and 5.44%, respectively. In general, BP:eHT13 showed higher sensitivity (ranging from 0.95 to 1.00) and specificity (ranging from 0.80 to 0.98) in detecting prehypertension, level I hypertension, and level II hypertension than BP:HT (sensitivity ranging from 0.91 to 1.00; specificity ranging from 0.59 to 0.89). The modified BP:eHT13 ratio showed better sensitivity and specificity for the screening of BP abnormalities in children aged 5-12 years. © American Journal of Hypertension, Ltd 2014. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. A New Multi-Sensor Fusion Scheme to Improve the Accuracy of Knee Flexion Kinematics for Functional Rehabilitation Movements.

    Science.gov (United States)

    Tannous, Halim; Istrate, Dan; Benlarbi-Delai, Aziz; Sarrazin, Julien; Gamet, Didier; Ho Ba Tho, Marie Christine; Dao, Tien Tuan

    2016-11-15

    Exergames have been proposed as a potential tool to improve the current practice of musculoskeletal rehabilitation. Inertial or optical motion capture sensors are commonly used to track the subject's movements. However, the use of these motion capture tools suffers from the lack of accuracy in estimating joint angles, which could lead to wrong data interpretation. In this study, we proposed a real time quaternion-based fusion scheme, based on the extended Kalman filter, between inertial and visual motion capture sensors, to improve the estimation accuracy of joint angles. The fusion outcome was compared to angles measured using a goniometer. The fusion output shows a better estimation, when compared to inertial measurement units and Kinect outputs. We noted a smaller error (3.96°) compared to the one obtained using inertial sensors (5.04°). The proposed multi-sensor fusion system is therefore accurate enough to be applied, in future works, to our serious game for musculoskeletal rehabilitation.

  9. Improved testing for microsatellite instability in colorectal cancer using a simplified 3-marker assay.

    Science.gov (United States)

    Esemuede, Iyare; Forslund, Ann; Khan, Sajid A; Qin, Li-Xuan; Gimbel, Mark I; Nash, Garrett M; Zeng, Zhaoshi; Rosenberg, Shoshana; Shia, Jinru; Barany, Francis; Paty, Philip B

    2010-12-01

    In colorectal cancer (CRC), microsatellite instability (MSI) is a valuable marker of defective DNA mismatch repair that identifies cancers with distinct phenotypic properties, including favorable survival. However, the optimal assay for MSI status is unknown. We have evaluated a simplified 3-marker assay for MSI and compared it with the 5-marker (NCI) assay to see if technical variations in MSI testing are important. DNA samples from 357 CRCs were evaluated for MSI using the 5 microsatellite markers recommended for the NCI assay (BAT 25, BAT26, D2S123, D5S346, and D17S250). Results were compared with a simplified 3-marker assay (BAT25, BAT26, and D2S123). CRCs identified as MSI were evaluated for their clinical, pathological, and genetic characteristics. The 5-marker assay identified 96 cancers as MSI. Only 56 of these were MSI by the 3-marker assay (3-marker+ group), leaving 40 cases identified as MSI only by NCI criteria (3-marker- group). The remaining 261 cancers were microsatellite stable (MSS). The 3-marker+ MSI tumors had features characteristic of MSI tumors: more proximal, poorly differentiated, associated with hereditary nonpolyposis colorectal cancer (HNPCC), more BRAF mutations, fewer KRAS mutations, better 5-year disease-specific survival, more frequent mismatch repair (MMR) protein loss, and less likely to be metastatic on presentation (P cancers (P colorectal cancer.

  10. Ultrasonication of pyrogenic microorganisms improves the detection of pyrogens in the Mono Mac 6 assay

    DEFF Research Database (Denmark)

    Moesby, Lise; Hansen, E W; Christensen, J D

    2000-01-01

    of the assay. The interleukin-6 inducing capacity of a broad spectrum of UV-killed and ultrasonicated microorganisms is examined in Mono Mac 6 cells. The interleukin-6 secretion is determined in a sandwich immunoassay (DELFIA). The Mono Mac 6 assay is able to detect UV-killed Bacillus subtilis, Staphylococcus......, ultrasonication of S. aureus results in a 100-fold increase in the interleukin-6 response. Even after ultrasonication Streptococcus faecalis can not be detected. Ultrasonication is an easy and simple method for expanding the detection range in the Mono Mac 6 assay....

  11. Improvements are needed in reporting of accuracy studies for diagnostic tests used for detection of finfish pathogens.

    Science.gov (United States)

    Gardner, Ian A; Burnley, Timothy; Caraguel, Charles

    2014-12-01

    Indices of test accuracy, such as diagnostic sensitivity and specificity, are important considerations in test selection for a defined purpose (e.g., screening or confirmation) and affect the interpretation of test results. Many biomedical journals recommend that authors clearly and transparently report test accuracy studies following the Standards for Reporting of Diagnostic Accuracy (STARD) guidelines ( www.stard-statement.org ). This allows readers to evaluate overall study validity and assess potential bias in diagnostic sensitivity and specificity estimates. The purpose of the present study was to evaluate the reporting quality of studies evaluating test accuracy for finfish diseases using the 25 items in the STARD checklist. Based on a database search, 11 studies that included estimates of diagnostic accuracy were identified for independent evaluation by three reviewers. For each study, STARD checklist items were scored as "yes," "no," or "not applicable." Only 10 of the 25 items were consistently reported in most (≥80%) papers, and reporting of the other items was highly variable (mostly between 30% and 60%). Three items ("number, training, and expertise of readers and testers"; "time interval between index tests and reference standard"; and "handling of indeterminate results, missing data, and outliers of the index tests") were reported in less than 10% of papers. Two items ("time interval between index tests and reference standard" and "adverse effects from testing") were considered minimally relevant to fish health because test samples usually are collected postmortem. Modification of STARD to fit finfish studies should increase use by authors and thereby improve the overall reporting quality regardless of how the study was designed. Furthermore, the use of STARD may lead to the improved design of future studies.

  12. A robot-aided visuo-motor training that improves proprioception and spatial accuracy of untrained movement.

    Science.gov (United States)

    Elangovan, Naveen; Cappello, Leonardo; Masia, Lorenzo; Aman, Joshua; Konczak, Jürgen

    2017-12-06

    Proprioceptive function can become enhanced during motor learning. Yet, we have incomplete knowledge to what extent proprioceptive function is trainable and how a training that enhances proprioception may influence performance in untrained motor skills. To address this knowledge gap, healthy young adults (N = 14) trained in a visuomotor task that required learners to make increasingly accurate wrist movements. Using a robotic exoskeleton coupled with a virtual visual environment, participants tilted a virtual table through continuous wrist flexion/extension movements with the goal to position a rolling ball on table into a target. With learning progress, the level of difficulty increased by altering the virtual ball mechanics and the gain between joint movement and ball velocity. Before and after training, wrist position sense acuity and spatial movement accuracy in an untrained, discrete wrist-pointing task was assessed using the same robot. All participants showed evidence of proprioceptive-motor learning. Mean position sense discrimination threshold improved by 34%. Wrist movement accuracy in the untrained pointing task improved by 27% in 13/14 participants. This demonstrates that a short sensorimotor training challenging proprioception can a) effectively enhance proprioceptive acuity and b) improve the accuracy of untrained movement. These findings provide a scientific basis for applying such somatosensory-based motor training to clinical populations with known proprioceptive dysfunction to enhance sensorimotor performance.

  13. Intensive care unit admission parameters improve the accuracy of operative mortality predictive models in cardiac surgery.

    Science.gov (United States)

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

    2010-10-21

    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. 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. 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). 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.

  14. Improved classification accuracy of powdery mildew infection levels of wine grapes by spatial-spectral analysis of hyperspectral images.

    Science.gov (United States)

    Knauer, Uwe; Matros, Andrea; Petrovic, Tijana; Zanker, Timothy; Scott, Eileen S; Seiffert, Udo

    2017-01-01

    Hyperspectral imaging is an emerging means of assessing plant vitality, stress parameters, nutrition status, and diseases. Extraction of target values from the high-dimensional datasets either relies on pixel-wise processing of the full spectral information, appropriate selection of individual bands, or calculation of spectral indices. Limitations of such approaches are reduced classification accuracy, reduced robustness due to spatial variation of the spectral information across the surface of the objects measured as well as a loss of information intrinsic to band selection and use of spectral indices. In this paper we present an improved spatial-spectral segmentation approach for the analysis of hyperspectral imaging data and its application for the prediction of powdery mildew infection levels (disease severity) of intact Chardonnay grape bunches shortly before veraison. Instead of calculating texture features (spatial features) for the huge number of spectral bands independently, dimensionality reduction by means of Linear Discriminant Analysis (LDA) was applied first to derive a few descriptive image bands. Subsequent classification was based on modified Random Forest classifiers and selective extraction of texture parameters from the integral image representation of the image bands generated. Dimensionality reduction, integral images, and the selective feature extraction led to improved classification accuracies of up to [Formula: see text] for detached berries used as a reference sample (training dataset). Our approach was validated by predicting infection levels for a sample of 30 intact bunches. Classification accuracy improved with the number of decision trees of the Random Forest classifier. These results corresponded with qPCR results. An accuracy of 0.87 was achieved in classification of healthy, infected, and severely diseased bunches. However, discrimination between visually healthy and infected bunches proved to be challenging for a few samples

  15. Solvent effects and improvements in the deoxyribose degradation assay for hydroxyl radical-scavenging.

    Science.gov (United States)

    Li, Xican

    2013-12-01

    The deoxyribose degradation assay is widely used to evaluate the hydroxyl (OH) radical-scavenging ability of food or medicines. We compared the hydroxyl radical-scavenging activity of 25 antioxidant samples prepared in ethanol solution with samples prepared after removing the ethanol (residue). The data suggested that there was an approximately 9-fold difference between assay results for the ethanol solution and residue samples. This indicated a strong alcoholic interference. To further study the mechanism, the scavenging activities of 18 organic solvents (including ethanol) were measured by the deoxyribose assay. Most pure organic solvents (especially alcohols) could effectively scavenge hydroxyl radicals. As hydroxyl radicals have extremely high reactivities, they will quickly react with surrounding solvent molecules. This shows that any organic solvent should be completely evaporated before measurement. The proposed method is regarded as a reliable hydroxyl radical-scavenging assay, suitable for all types of antioxidants. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Development of an improved RT-LAMP assay for detection of currently circulating rubella viruses.

    Science.gov (United States)

    Abo, H; Okamoto, K; Anraku, M; Otsuki, N; Sakata, M; Icenogle, J; Zheng, Q; Kurata, T; Kase, T; Komase, K; Takeda, M; Mori, Y

    2014-10-01

    Rubella virus is the causative agent of rubella. The symptoms are usually mild, and characterized by a maculopapular rash and fever. However, rubella infection in pregnant women sometimes can result in the birth of infants with congenital rubella syndrome (CRS). Global efforts have been made to reduce and eliminate CRS. Although a reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay for detection of rubella virus has been reported, the primers contained several mismatched nucleotides with the genomes of currently circulating rubella virus strains. In the present study, a new RT-LAMP assay was established. The detection limit of this assay was 100-1000PFU/reaction of viruses for all rubella genotypes, except for genotype 2C, which is not commonly found in the current era. Therefore, the new RT-LAMP assay can successfully detect all current rubella virus genotypes, and does not require sophisticated devices like TaqMan real-time PCR systems. This assay should be a useful assay for laboratory diagnosis of rubella and CRS. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Improvement of registration accuracy of a handheld augmented reality system for urban landscape simulation

    Directory of Open Access Journals (Sweden)

    Tomohiro Fukuda

    2014-12-01

    Full Text Available The need for visual landscape assessment in large-scale projects for the evaluation of the effects of a particular project on the surrounding landscape has grown in recent years. Augmented reality (AR has been considered for use as a landscape simulation system in which a landscape assessment object created by 3D models is included in the present surroundings. With the use of this system, the time and the cost needed to perform a 3DCG modeling of present surroundings, which is a major issue in virtual reality, are drastically reduced. This research presents the development of a 3D map-oriented handheld AR system that achieves geometric consistency using a 3D map to obtain position data instead of GPS, which has low position information accuracy, particularly in urban areas. The new system also features a gyroscope sensor to obtain posture data and a video camera to capture live video of the present surroundings. All these components are mounted in a smartphone and can be used for urban landscape assessment. Registration accuracy is evaluated to simulate an urban landscape from a short- to a long-range scale. The latter involves a distance of approximately 2000 m. The developed AR system enables users to simulate a landscape from multiple and long-distance viewpoints simultaneously and to walk around the viewpoint fields using only a smartphone. This result is the tolerance level of landscape assessment. In conclusion, the proposed method is evaluated as feasible and effective.

  18. High-accuracy extrapolated ab initio thermochemistry. II. Minor improvements to the protocol and a vital simplification.

    Science.gov (United States)

    Bomble, Yannick J; Vázquez, Juana; Kállay, Mihály; Michauk, Christine; Szalay, Péter G; Császár, Attila G; Gauss, Jürgen; Stanton, John F

    2006-08-14

    The recently developed high-accuracy extrapolated ab initio thermochemistry method for theoretical thermochemistry, which is intimately related to other high-precision protocols such as the Weizmann-3 and focal-point approaches, is revisited. Some minor improvements in theoretical rigor are introduced which do not lead to any significant additional computational overhead, but are shown to have a negligible overall effect on the accuracy. In addition, the method is extended to completely treat electron correlation effects up to pentuple excitations. The use of an approximate treatment of quadruple and pentuple excitations is suggested; the former as a pragmatic approximation for standard cases and the latter when extremely high accuracy is required. For a test suite of molecules that have rather precisely known enthalpies of formation {as taken from the active thermochemical tables of Ruscic and co-workers [Lecture Notes in Computer Science, edited by M. Parashar (Springer, Berlin, 2002), Vol. 2536, pp. 25-38; J. Phys. Chem. A 108, 9979 (2004)]}, the largest deviations between theory and experiment are 0.52, -0.70, and 0.51 kJ mol(-1) for the latter three methods, respectively. Some perspective is provided on this level of accuracy, and sources of remaining systematic deficiencies in the approaches are discussed.

  19. Improvement of Dimensional Accuracy of 3-D Printed Parts using an Additive/Subtractive Based Hybrid Prototyping Approach

    Science.gov (United States)

    Amanullah Tomal, A. N. M.; Saleh, Tanveer; Raisuddin Khan, Md.

    2017-11-01

    At present, two important processes, namely CNC machining and rapid prototyping (RP) are being used to create prototypes and functional products. Combining both additive and subtractive processes into a single platform would be advantageous. However, there are two important aspects need to be taken into consideration for this process hybridization. First is the integration of two different control systems for two processes and secondly maximizing workpiece alignment accuracy during the changeover step. Recently we have developed a new hybrid system which incorporates Fused Deposition Modelling (FDM) as RP Process and CNC grinding operation as subtractive manufacturing process into a single setup. Several objects were produced with different layer thickness for example 0.1 mm, 0.15 mm and 0.2 mm. It was observed that pure FDM method is unable to attain desired dimensional accuracy and can be improved by a considerable margin about 66% to 80%, if finishing operation by grinding is carried out. It was also observed layer thickness plays a role on the dimensional accuracy and best accuracy is achieved with the minimum layer thickness (0.1 mm).

  20. Diagnostic accuracy of quantitative heart-fatty acid binding protein assays compared with Cardiodetect(®) in the early detection of acute coronary syndrome.

    Science.gov (United States)

    Charpentier, Sandrine; Maupas-Schwalm, Françoise; Cournot, Maxime; Elbaz, Meyer; Ducassé, Jean-Louis; Bottela, Jean-Marie; Lauque, Dominique

    2011-10-01

    Heart-fatty acid binding protein (h-FABP) has been proposed as a cardiac marker for the early detection of acute coronary syndrome (ACS). In a study of 677 patients admitted to the emergency department (ED) for chest pain, we found that a semiquantitative point-of-care test that detects h-FABP (Cardiodetect(®)) had low sensitivity for the prediction of ACS. The aim of this ancillary study was to analyze and compare the performance of h-FABP for early ACS diagnosis in this large cohort of unselected patients, using a quantitative immunoassay and Cardiodetect(®). h-FABP was measured with a ready-to-use, solid-phase, enzyme-linked immunosorbent assay (ELISA) in 677 patients admitted to the ED with chest pain and suspected non-ST-segment elevation ACS. Two physicians, blinded to the results of the marker, categorized patients as having or not having non-ST-segment elevation ACS. Non-ST-segment elevation ACS was diagnosed in 185 patients (27.3%). The median h-FABP level was higher in patients with ACS (1.36μg/L, interquartile range [IQR] 0.59-3.55) than in those without ACS (0.58μg/L, IQR 0.24-1.34; P<0.01). The area under the curve was 0.68 (95% confidence interval [CI] 0.63-0.73). h-FABP did not improve the performance of a model that included the usual diagnostic tools for ACS management (odds ratio 0.92, 95% CI 0.32-2.70). The classification agreement between the ELISA and Cardiodetect(®) was 92.1% (kappa 0.39). In this study, we confirmed that measurement of h-FABP was insufficient to be used as a marker of ACS and NSTEMI in ED, whatever the analytical technique used. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  1. Combination of DKK1 and AFP improves diagnostic accuracy of hepatocellular carcinoma compared with either marker alone.

    Science.gov (United States)

    Erdal, Harun; Gül Utku, Özlem; Karatay, Eylem; Çelik, Bülent; Elbeg, Şehri; Doğan, İbrahim

    2016-07-01

    The Wnt/ß-catenin pathway plays a prominent role in hepatocellular carcinoma (HCC). The Dickkopf (DKK) proteins (DKK1-4) are known Wnt antagonists; the overexpression of DKK1 has been demonstrated in HCC, and increased DKK3 methylation in the HCC tissue is associated with worse prognosis. Thus, the aim of our study was to demonstrate the diagnostic accuracy of serum DKK1 and DKK3 in HCC in comparison with that of serum alpha-fetoprotein (AFP). We included consecutive 40 HCC patients, 54 cirrhosis patients, and 39 healthy controls. Serum DKK1 and DKK3 levels were measured by an enzyme-linked immunosorbent assay, and serum AFP levels were measured by a chemiluminescence assay. The AFP levels differed in each group and could help differentiate between groups (p AFP increased the diagnostic yield, with a sensitivity, specificity, positive predictive value, and negative predictive value of 87.5%, 92.3%, 92.1%, and 87.8%, respectively. Although AFP is superior to DKK1 and DKK3 in the diagnosis of HCC, the combination of DKK1 and AFP showed a better diagnostic yield than AFP alone.

  2. Can physiological endpoints improve the sensitivity of assays with plants in the risk assessment of contaminated soils?

    Directory of Open Access Journals (Sweden)

    Ana Gavina

    Full Text Available Site-specific risk assessment of contaminated areas indicates prior areas for intervention, and provides helpful information for risk managers. This study was conducted in the Ervedosa mine area (Bragança, Portugal, where both underground and open pit exploration of tin and arsenic minerals were performed for about one century (1857-1969. We aimed at obtaining ecotoxicological information with terrestrial and aquatic plant species to integrate in the risk assessment of this mine area. Further we also intended to evaluate if the assessment of other parameters, in standard assays with terrestrial plants, can improve the identification of phytotoxic soils. For this purpose, soil samples were collected on 16 sampling sites distributed along four transects, defined within the mine area, and in one reference site. General soil physical and chemical parameters, total and extractable metal contents were analyzed. Assays were performed for soil elutriates and for the whole soil matrix following standard guidelines for growth inhibition assay with Lemna minor and emergence and seedling growth assay with Zea mays. At the end of the Z. mays assay, relative water content, membrane permeability, leaf area, content of photosynthetic pigments (chlorophylls and carotenoids, malondialdehyde levels, proline content, and chlorophyll fluorescence (Fv/Fm and ΦPSII parameters were evaluated. In general, the soils near the exploration area revealed high levels of Al, Mn, Fe and Cu. Almost all the soils from transepts C, D and F presented total concentrations of arsenic well above soils screening benchmark values available. Elutriates of several soils from sampling sites near the exploration and ore treatment areas were toxic to L. minor, suggesting that the retention function of these soils was seriously compromised. In Z. mays assay, plant performance parameters (other than those recommended by standard protocols, allowed the identification of more phytotoxic soils

  3. Improvement in the accuracy of polymer gel dosimeters using scintillating fibers

    Energy Technology Data Exchange (ETDEWEB)

    Tremblay, Nicolas M; Hubert-Tremblay, Vincent; Bujold, Rachel; Beaulieu, Luc; Lepage, Martin, E-mail: Martin.Lepage@USherbrooke.c

    2010-11-01

    We propose a novel method for the absolute calibration of polyacrylamide gel (PAG) dosimeters with one or more reference scintillating fiber dosimeters inserted inside the gel. Four calibrated scintillating fibers were inserted into a cylindrical glass container filled with a PAG dosimeter irradiated with a wedge filtered 6 MV photon beam. Calibration curves using small glass vials containing the same gel as the cylindrical containers were used to obtain a first calibration curve. This calibration curve was then adjusted with the dose measured with one of the scintillating fibers in a low gradient part of the field using different approaches. Among these, it was found that a translation of the gel calibration curve yielded the highest accuracy with PAG dosimeters.

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

    Science.gov (United States)

    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.

  5. Improved Accuracy of Density Functional Theory Calculations for CO2 Reduction and Metal-Air Batteries

    DEFF Research Database (Denmark)

    Christensen, Rune; Hansen, Heine Anton; Vegge, Tejs

    2015-01-01

    .e. the electrocatalytic reduction of CO2 and metal-air batteries. In theoretical studies of electrocatalytic CO2 reduction, calculated DFT-level enthalpies of reaction for CO2reduction to various products are significantly different from experimental values[1-3]. In theoretical studies of metal-air battery reactions...... errors in DFT-level computational electrocatalytic CO2reduction is hence identified. The new insight adds increased accuracy e.g., for reaction to formic acid, where the experimental enthalpy of reaction is 0.15 eV. Previously, this enthalpy has been calculated without and with correctional approaches......, Nano Lett., 14, 1016 (2014) [6] J. Wellendorff, K. T. Lundgaard, A. Møgelhøj, V. Petzold, D. D. Landis, J. K. Nørskov, T. Bligaard, and K. W. Jacobsen, Phys. Rev. B, 85, 235149 (2012) Figure 1: Calculated enthalpies of reaction from CO2 to CH3OH (x axis) and HCOOH (y axis). Functional variations...

  6. Improving the Accuracy of Satellite Sea Surface Temperature Measurements by Explicitly Accounting for the Bulk-Skin Temperature Difference

    Science.gov (United States)

    Castro, Sandra L.; Emery, William J.

    2002-01-01

    The focus of this research was to determine whether the accuracy of satellite measurements of sea surface temperature (SST) could be improved by explicitly accounting for the complex temperature gradients at the surface of the ocean associated with the cool skin and diurnal warm layers. To achieve this goal, work centered on the development and deployment of low-cost infrared radiometers to enable the direct validation of satellite measurements of skin temperature. During this one year grant, design and construction of an improved infrared radiometer was completed and testing was initiated. In addition, development of an improved parametric model for the bulk-skin temperature difference was completed using data from the previous version of the radiometer. This model will comprise a key component of an improved procedure for estimating the bulk SST from satellites. The results comprised a significant portion of the Ph.D. thesis completed by one graduate student and they are currently being converted into a journal publication.

  7. The Application of Digital Pathology to Improve Accuracy in Glomerular Enumeration in Renal Biopsies.

    Directory of Open Access Journals (Sweden)

    Avi Z Rosenberg

    Full Text Available In renal biopsy reporting, quantitative measurements, such as glomerular number and percentage of globally sclerotic glomeruli, is central to diagnostic accuracy and prognosis. The aim of this study is to determine the number of glomeruli and percent globally sclerotic in renal biopsies by means of registration of serial tissue sections and manual enumeration, compared to the numbers in pathology reports from routine light microscopic assessment.We reviewed 277 biopsies from the Nephrotic Syndrome Study Network (NEPTUNE digital pathology repository, enumerating 9,379 glomeruli by means of whole slide imaging. Glomerular number and the percentage of globally sclerotic glomeruli are values routinely recorded in the official renal biopsy pathology report from the 25 participating centers. Two general trends in reporting were noted: total number per biopsy or average number per level/section. Both of these approaches were assessed for their accuracy in comparison to the analogous numbers of annotated glomeruli on WSI.The number of glomeruli annotated was consistently higher than those reported (p<0.001; this difference was proportional to the number of glomeruli. In contrast, percent globally sclerotic were similar when calculated on total glomeruli, but greater in FSGS when calculated on average number of glomeruli (p<0.01. The difference in percent globally sclerotic between annotated and those recorded in pathology reports was significant when global sclerosis is greater than 40%.Although glass slides were not available for direct comparison to whole slide image annotation, this study indicates that routine manual light microscopy assessment of number of glomeruli is inaccurate, and the magnitude of this error is proportional to the total number of glomeruli.

  8. Predicting sulfotyrosine sites using the random forest algorithm with significantly improved prediction accuracy

    Directory of Open Access Journals (Sweden)

    Yang Zheng

    2009-10-01

    Full Text Available Abstract Background Tyrosine sulfation is one of the most important posttranslational modifications. Due to its relevance to various disease developments, tyrosine sulfation has become the target for drug design. In order to facilitate efficient drug design, accurate prediction of sulfotyrosine sites is desirable. A predictor published seven years ago has been very successful with claimed prediction accuracy of 98%. However, it has a particularly low sensitivity when predicting sulfotyrosine sites in some newly sequenced proteins. Results A new approach has been developed for predicting sulfotyrosine sites using the random forest algorithm after a careful evaluation of seven machine learning algorithms. Peptides are formed by consecutive residues symmetrically flanking tyrosine sites. They are then encoded using an amino acid hydrophobicity scale. This new approach has increased the sensitivity by 22%, the specificity by 3%, and the total prediction accuracy by 10% compared with the previous predictor using the same blind data. Meanwhile, both negative and positive predictive powers have been increased by 9%. In addition, the random forest model has an excellent feature for ranking the residues flanking tyrosine sites, hence providing more information for further investigating the tyrosine sulfation mechanism. A web tool has been implemented at http://ecsb.ex.ac.uk/sulfotyrosine for public use. Conclusion The random forest algorithm is able to deliver a better model compared with the Hidden Markov Model, the support vector machine, artificial neural networks, and others for predicting sulfotyrosine sites. The success shows that the random forest algorithm together with an amino acid hydrophobicity scale encoding can be a good candidate for peptide classification.

  9. Intellijoint HIP®: a 3D mini-optical navigation tool for improving intraoperative accuracy during total hip arthroplasty

    Directory of Open Access Journals (Sweden)

    Paprosky WG

    2016-11-01

    Full Text Available Wayne G Paprosky,1,2 Jeffrey M Muir3 1Department of Orthopedics, Section of Adult Joint Reconstruction, Department of Orthopedics, Rush University Medical Center, Rush–Presbyterian–St Luke’s Medical Center, Chicago, 2Central DuPage Hospital, Winfield, IL, USA; 3Intellijoint Surgical, Inc, Waterloo, ON, Canada Abstract: Total hip arthroplasty is an increasingly common procedure used to address degenerative changes in the hip joint due to osteoarthritis. Although generally associated with good results, among the challenges associated with hip arthroplasty are accurate measurement of biomechanical parameters such as leg length, offset, and cup position, discrepancies of which can lead to significant long-term consequences such as pain, instability, neurological deficits, dislocation, and revision surgery, as well as patient dissatisfaction and, increasingly, litigation. Current methods of managing these parameters are limited, with manual methods such as outriggers or calipers being used to monitor leg length; however, these are susceptible to small intraoperative changes in patient position and are therefore inaccurate. Computer-assisted navigation, while offering improved accuracy, is expensive and cumbersome, in addition to adding significantly to procedural time. To address the technological gap in hip arthroplasty, a new intraoperative navigation tool (Intellijoint HIP® has been developed. This innovative, 3D mini-optical navigation tool provides real-time, intraoperative data on leg length, offset, and cup position and allows for improved accuracy and precision in component selection and alignment. Benchtop and simulated clinical use testing have demonstrated excellent accuracy, with the navigation tool able to measure leg length and offset to within <1 mm and cup position to within <1° in both anteversion and inclination. This study describes the indications, procedural technique, and early accuracy results of the Intellijoint HIP

  10. Improving dose homogeneity in large breasts by IMRT. Efficacy and dosimetric accuracy of different techniques

    Energy Technology Data Exchange (ETDEWEB)

    Abo-Madyan, Y. [Dept. of Radiation Oncology, Mannheim Medical Center, Univ. of Heidelberg, Mannheim (Germany); Dept. of Radiation Oncology and Nuclear Medicine (NEMROCK), Faculty of Medicine, Univ. of Cairo (Egypt); Polednik, M.; Rahn, A.; Schneider, F.; Dobler, B.; Wenz, F.; Lohr, F. [Dept. of Radiation Oncology, Mannheim Medical Center, Univ. of Heidelberg, Mannheim (Germany)

    2008-02-15

    Purpose: evaluation of a simplified intensity-modulated irradiation (IMRT), a three-field (MFT), and a conventional two-tangential-field technique regarding dose homogeneity, target coverage, feasibility and, for the first time, dosimetric reliability in patients with large breasts treated postoperatively for breast cancer on a low-energy linac. Material and methods: CT datasets of ten patients with relatively large breast volumes treated for breast cancer were selected. For each patient, four treatment plans were created: low-energy conventional (C-LE), high-energy conventional (C-HE), three-field (MFT), and a two-field aperture-based IMRT technique. Apertures for the IMRT and MFT were created with the aid of a three-dimensional dose display. Dosimetric accuracy of each technique was evaluated in an anthropomorphic thorax/breast phantom. Results: the mean of planning target volumes receiving < 95% or > 105% of the prescribed total dose was reduced from 16.0% to 13.9% to 10.4% to 8.9% in the C-LE, C-HE, MFT, and IMRT plans, respectively. Phantom dose measurements agreed well with the calculated dose within the breast tissue. Conclusion: aperture-based IMRT using two tangential incident beam directions, as well as a three-field technique with inverse optimization, provide a better alternative to the standard wedged tangential beams for patients with large breasts treated on low-energy linacs while maintaining the efficiency of the treatment-planning and delivery process. (orig.)

  11. Pseudo-inverse linear discriminants for the improvement of overall classification accuracies.

    Science.gov (United States)

    Daqi, Gao; Ahmed, Dastagir; Lili, Guo; Zejian, Wang; Zhe, Wang

    2016-09-01

    This paper studies the learning and generalization performances of pseudo-inverse linear discriminant (PILDs) based on the processing minimum sum-of-squared error (MS(2)E) and the targeting overall classification accuracy (OCA) criterion functions. There is little practicable significance to prove the equivalency between a PILD with the desired outputs in reverse proportion to the number of class samples and an FLD with the totally projected mean thresholds. When the desired outputs of each class are assigned a fixed value, a PILD is partly equal to an FLD. With the customarily desired outputs {1, -1}, a practicable threshold is acquired, which is only related to sample sizes. If the desired outputs of each sample are changeable, a PILD has nothing in common with an FLD. The optimal threshold may thus be singled out from multiple empirical ones related to sizes and distributed regions. Depending upon the processing MS(2)E criteria and the actually algebraic distances, an iterative learning strategy of PILD is proposed, the outstanding advantages of which are with limited epoch, without learning rate and divergent risk. Enormous experimental results for the benchmark datasets have verified that the iterative PILDs with optimal thresholds have good learning and generalization performances, and even reach the top OCAs for some datasets among the existing classifiers. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Parametric Study to Improve Subpixel Accuracy of Nitric Oxide Tagging Velocimetry with Image Preprocessing

    Directory of Open Access Journals (Sweden)

    Ravi Teja Vedula

    2017-01-01

    Full Text Available Biacetyl phosphorescence has been the commonly used molecular tagging velocimetry (MTV technique to investigate in-cylinder flow evolution and cycle-to-cycle variations in an optical engine. As the phosphorescence of biacetyl tracer deteriorates in the presence of oxygen, nitrogen was adopted as the working medium in the past. Recently, nitrous oxide MTV technique was employed to measure the velocity profile of an air jet. The authors here plan to investigate the potential application of this technique for engine flow studies. A possible experimental setup for this task indicated different permutations of image signal-to-noise ratio (SNR and laser line width. In the current work, a numerical analysis is performed to study the effect of these two factors on displacement error in MTV image processing. Also, several image filtering techniques were evaluated and the performance of selected filters was analyzed in terms of enhancing the image quality and minimizing displacement errors. The flow displacement error without image preprocessing was observed to be inversely proportional to SNR and directly proportional to laser line width. The mean filter resulted in the smallest errors for line widths smaller than 9 pixels. The effect of filter size on subpixel accuracy showed that error levels increased as the filter size increased.

  13. Iterative error correction of long sequencing reads maximizes accuracy and improves contig assembly.

    Science.gov (United States)

    Sameith, Katrin; Roscito, Juliana G; Hiller, Michael

    2017-01-01

    Next-generation sequencers such as Illumina can now produce reads up to 300 bp with high throughput, which is attractive for genome assembly. A first step in genome assembly is to computationally correct sequencing errors. However, correcting all errors in these longer reads is challenging. Here, we show that reads with remaining errors after correction often overlap repeats, where short erroneous k-mers occur in other copies of the repeat. We developed an iterative error correction pipeline that runs the previously published String Graph Assembler (SGA) in multiple rounds of k-mer-based correction with an increasing k-mer size, followed by a final round of overlap-based correction. By combining the advantages of small and large k-mers, this approach corrects more errors in repeats and minimizes the total amount of erroneous reads. We show that higher read accuracy increases contig lengths two to three times. We provide SGA-Iteratively Correcting Errors (https://github.com/hillerlab/IterativeErrorCorrection/) that implements iterative error correction by using modules from SGA. © The Author 2016. Published by Oxford University Press.

  14. Application of an improved enzyme-linked immunosorbent assay method for serological diagnosis of canine leishmaniasis

    NARCIS (Netherlands)

    Santarém, Nuno; Silvestre, Ricardo; Cardoso, Luís; Schallig, Henk; Reed, Steven G.; Cordeiro-da-Silva, Anabela

    2010-01-01

    Accurate diagnosis of canine leishmaniasis (CanL) is essential toward a more efficient control of this zoonosis, but it remains problematic due to the high incidence of asymptomatic infections. In this study, we present data on the development of enzyme-linked immunosorbent assay (ELISA)-based

  15. A mass spectrometry-based assay for improved quantitative measurements of efflux pump inhibition.

    Directory of Open Access Journals (Sweden)

    Adam R Brown

    Full Text Available Bacterial efflux pumps are active transport proteins responsible for resistance to selected biocides and antibiotics. It has been shown that production of efflux pumps is up-regulated in a number of highly pathogenic bacteria, including methicillin resistant Staphylococcus aureus. Thus, the identification of new bacterial efflux pump inhibitors is a topic of great interest. Existing assays to evaluate efflux pump inhibitory activity rely on fluorescence by an efflux pump substrate. When employing these assays to evaluate efflux pump inhibitory activity of plant extracts and some purified compounds, we observed severe optical interference that gave rise to false negative results. To circumvent this problem, a new mass spectrometry-based method was developed for the quantitative measurement of bacterial efflux pump inhibition. The assay was employed to evaluate efflux pump inhibitory activity of a crude extract of the botanical Hydrastis Canadensis, and to compare the efflux pump inhibitory activity of several pure flavonoids. The flavonoid quercetin, which appeared to be completely inactive with a fluorescence-based method, showed an IC50 value of 75 μg/mL with the new method. The other flavonoids evaluated (apigenin, kaempferol, rhamnetin, luteolin, myricetin, were also active, with IC50 values ranging from 19 μg/mL to 75 μg/mL. The assay described herein could be useful in future screening efforts to identify efflux pump inhibitors, particularly in situations where optical interference precludes the application of methods that rely on fluorescence.

  16. Economic Value of Improved Accuracy for Self-Monitoring of Blood Glucose Devices for Type 1 Diabetes in Canada.

    Science.gov (United States)

    McQueen, R Brett; Breton, Marc D; Ott, Markus; Koa, Helena; Beamer, Bruce; Campbell, Jonathan D

    2015-08-14

    The objective was to simulate and compare clinical and economic outcomes of self-monitoring of blood glucose (SMBG) devices along error ranges and strip price. We programmed a type 1 diabetes natural history and treatment cost-effectiveness model. In phase 1, using past evidence from in silico modeling validated by the Food and Drug Administration, we associated changes in SMBG error to changes in hemoglobin A1c (HbA1c) and separately, changes in severe hypoglycemia requiring an inpatient stay. In phase 2, using Markov cohort simulation modeling, we estimated clinical and economic outcomes from the Canadian payer perspective. The primary comparison was a SMBG device with strip price $0.73 Canadian dollars (CAD) and 10% error (exceeding accuracy requirements by International Organization for Standardization (ISO) 15197:2013) versus a SMBG device with strip price $0.60 CAD and 15% error (accuracy meeting ISO 15197:2013). Outcomes for the average patient, were quality-adjusted life years (QALYs), incremental cost-effectiveness ratios (ICERs), and budget impact. Assuming benefits translate into HbA1c improvements only, the ICER with 10% error versus 15% was $11 500 CAD per QALY. Assuming the benefits translate into reduced severe hypoglycemia requiring an inpatient stay only, an SMBG device with 10% error dominated (ie, less costly, more effective) an SMBG device with 15% error. The 3-year budget impact findings ranged from $0.004 CAD per member per month for HbA1c improvements to cost-savings for severe hypoglycemia reductions. From efficiency (cost-effectiveness) and affordability (budget impact) payer perspectives, investing in devices with improved accuracy (less error) appears to be an efficient and affordable strategy. © 2015 Diabetes Technology Society.

  17. Improving the Accuracy of Mapping Urban Vegetation Carbon Density by Combining Shadow Remove, Spectral Unmixing Analysis and Spatial Modeling

    Science.gov (United States)

    Qie, G.; Wang, G.; Wang, M.

    2016-12-01

    Mixed pixels and shadows due to buildings in urban areas impede accurate estimation and mapping of city vegetation carbon density. In most of previous studies, these factors are often ignored, which thus result in underestimation of city vegetation carbon density. In this study we presented an integrated methodology to improve the accuracy of mapping city vegetation carbon density. Firstly, we applied a linear shadow remove analysis (LSRA) on remotely sensed Landsat 8 images to reduce the shadow effects on carbon estimation. Secondly, we integrated a linear spectral unmixing analysis (LSUA) with a linear stepwise regression (LSR), a logistic model-based stepwise regression (LMSR) and k-Nearest Neighbors (kNN), and utilized and compared the integrated models on shadow-removed images to map vegetation carbon density. This methodology was examined in Shenzhen City of Southeast China. A data set from a total of 175 sample plots measured in 2013 and 2014 was used to train the models. The independent variables statistically significantly contributing to improving the fit of the models to the data and reducing the sum of squared errors were selected from a total of 608 variables derived from different image band combinations and transformations. The vegetation fraction from LSUA was then added into the models as an important independent variable. The estimates obtained were evaluated using a cross-validation method. Our results showed that higher accuracies were obtained from the integrated models compared with the ones using traditional methods which ignore the effects of mixed pixels and shadows. This study indicates that the integrated method has great potential on improving the accuracy of urban vegetation carbon density estimation. Key words: Urban vegetation carbon, shadow, spectral unmixing, spatial modeling, Landsat 8 images

  18. Investigations to improve and assess the accuracy of computational fluid dynamic based explosion models

    NARCIS (Netherlands)

    Popat, N.R.; Catlin, C.A.; Arntzen, B.J.; Lindstedt, R.P.; Hjertager, B.H.; Solberg, T.; Saeter, O.; Berg, A.C. van den

    1996-01-01

    A summary is given of part of the CEC co-sponsored project MERGE (Modelling and Experimental Research into Gas Explosions). The objective of this part of the project was to provide improved Computational Fluid Dynamic explosion models with the potential for use in hazard assessments. Five

  19. Improving the Grammatical Accuracy of the Spoken English of Indonesian International Kindergarten Students

    Science.gov (United States)

    Gozali, Imelda; Harjanto, Ignatius

    2014-01-01

    The need to improve the spoken English of kindergarten students in an international preschool in Surabaya prompted this Classroom Action Research (CAR). It involved the implementation of Form-Focused Instruction (FFI) strategy coupled with Corrective Feedback (CF) in Grammar lessons. Four grammar topics were selected, namely Regular Plural form,…

  20. Degenerate adaptor sequences for detecting PCR duplicates in reduced representation sequencing data improve genotype calling accuracy.

    Science.gov (United States)

    Tin, M M Y; Rheindt, F E; Cros, E; Mikheyev, A S

    2015-03-01

    RAD-tag is a powerful tool for high-throughput genotyping. It relies on PCR amplification of the starting material, following enzymatic digestion and sequencing adaptor ligation. Amplification introduces duplicate reads into the data, which arise from the same template molecule and are statistically nonindependent, potentially introducing errors into genotype calling. In shotgun sequencing, data duplicates are removed by filtering reads starting at the same position in the alignment. However, restriction enzymes target specific locations within the genome, causing reads to start in the same place, and making it difficult to estimate the extent of PCR duplication. Here, we introduce a slight change to the Illumina sequencing adaptor chemistry, appending a unique four-base tag to the first index read, which allows duplicate discrimination in aligned data. This approach was validated on the Illumina MiSeq platform, using double-digest libraries of ants (Wasmannia auropunctata) and yeast (Saccharomyces cerevisiae) with known genotypes, producing modest though statistically significant gains in the odds of calling a genotype accurately. More importantly, removing duplicates also corrected for strong sample-to-sample variability of genotype calling accuracy seen in the ant samples. For libraries prepared from low-input degraded museum bird samples (Mixornis gularis), which had low complexity, having been generated from relatively few starting molecules, adaptor tags show that virtually all of the genotypes were called with inflated confidence as a result of PCR duplicates. Quantification of library complexity by adaptor tagging does not significantly increase the difficulty of the overall workflow or its cost, but corrects for differences in quality between samples and permits analysis of low-input material. © 2014 John Wiley & Sons Ltd.

  1. Detecting representative data and generating synthetic samples to improve learning accuracy with imbalanced data sets.

    Directory of Open Access Journals (Sweden)

    Der-Chiang Li

    Full Text Available It is difficult for learning models to achieve high classification performances with imbalanced data sets, because with imbalanced data sets, when one of the classes is much larger than the others, most machine learning and data mining classifiers are overly influenced by the larger classes and ignore the smaller ones. As a result, the classification algorithms often have poor learning performances due to slow convergence in the smaller classes. To balance such data sets, this paper presents a strategy that involves reducing the sizes of the majority data and generating synthetic samples for the minority data. In the reducing operation, we use the box-and-whisker plot approach to exclude outliers and the Mega-Trend-Diffusion method to find representative data from the majority data. To generate the synthetic samples, we propose a counterintuitive hypothesis to find the distributed shape of the minority data, and then produce samples according to this distribution. Four real datasets were used to examine the performance of the proposed approach. We used paired t-tests to compare the Accuracy, G-mean, and F-measure scores of the proposed data pre-processing (PPDP method merging in the D3C method (PPDP+D3C with those of the one-sided selection (OSS, the well-known SMOTEBoost (SB study, and the normal distribution-based oversampling (NDO approach, and the proposed data pre-processing (PPDP method. The results indicate that the classification performance of the proposed approach is better than that of above-mentioned methods.

  2. An evaluation of the effectiveness of PROMPT therapy in improving speech production accuracy in six children with cerebral palsy.

    Science.gov (United States)

    Ward, Roslyn; Leitão, Suze; Strauss, Geoff

    2014-08-01

    This study evaluates perceptual changes in speech production accuracy in six children (3-11 years) with moderate-to-severe speech impairment associated with cerebral palsy before, during, and after participation in a motor-speech intervention program (Prompts for Restructuring Oral Muscular Phonetic Targets). An A1BCA2 single subject research design was implemented. Subsequent to the baseline phase (phase A1), phase B targeted each participant's first intervention priority on the PROMPT motor-speech hierarchy. Phase C then targeted one level higher. Weekly speech probes were administered, containing trained and untrained words at the two levels of intervention, plus an additional level that served as a control goal. The speech probes were analysed for motor-speech-movement-parameters and perceptual accuracy. Analysis of the speech probe data showed all participants recorded a statistically significant change. Between phases A1-B and B-C 6/6 and 4/6 participants, respectively, recorded a statistically significant increase in performance level on the motor speech movement patterns targeted during the training of that intervention. The preliminary data presented in this study make a contribution to providing evidence that supports the use of a treatment approach aligned with dynamic systems theory to improve the motor-speech movement patterns and speech production accuracy in children with cerebral palsy.

  3. Improved classification accuracy in 1- and 2-dimensional NMR metabolomics data using the variance stabilising generalised logarithm transformation

    Directory of Open Access Journals (Sweden)

    Günther Ulrich L

    2007-07-01

    variance in NMR metabolomics datasets. This significantly improves the discrimination between sample classes and has resulted in higher classification accuracies compared to unscaled, autoscaled or Pareto scaled data. Additionally we have confirmed the broad applicability of the glog approach using three disparate datasets from different biological samples using 1D NMR spectra, 1D projections of 2D JRES spectra, and intact 2D JRES spectra.

  4. New possibilities for improving the accuracy of parameter calculations for cascade gamma-ray decay of heavy nuclei

    CERN Document Server

    Sukhovoj, A M; Khitrov, V A

    2001-01-01

    The level density and radiative strength functions which accurately reproduce the experimental intensity of two- step cascades after thermal neutron capture and the total radiative widths of the compound states were applied to calculate the total gamma-ray spectra from the (n,gamma) reaction. In some cases, analysis showed far better agreement with experiment and gave insight into possible ways in which these parameters need to be corrected for further improvement of calculation accuracy for the cascade gamma-decay of heavy nuclei.

  5. Accuracy Improvement of the Method of Multiple Scales for Nonlinear Vibration Analyses of Continuous Systems with Quadratic and Cubic Nonlinearities

    Directory of Open Access Journals (Sweden)

    Akira Abe

    2010-01-01

    and are the driving and natural frequencies, respectively. The application of Galerkin's procedure to the equation of motion yields nonlinear ordinary differential equations with quadratic and cubic nonlinear terms. The steady-state responses are obtained by using the discretization approach of the MMS in which the definition of the detuning parameter, expressing the relationship between the natural frequency and the driving frequency, is changed in an attempt to improve the accuracy of the solutions. The validity of the solutions is discussed by comparing them with solutions of the direct approach of the MMS and the finite difference method.

  6. Accurate Region-of-Interest Recovery Improves the Measurement of the Cell Migration Rate in the In Vitro Wound Healing Assay.

    Science.gov (United States)

    Bedoya, Cesar; Cardona, Andrés; Galeano, July; Cortés-Mancera, Fabián; Sandoz, Patrick; Zarzycki, Artur

    2017-12-01

    The wound healing assay is widely used for the quantitative analysis of highly regulated cellular events. In this essay, a wound is voluntarily produced on a confluent cell monolayer, and then the rate of wound reduction (WR) is characterized by processing images of the same regions of interest (ROIs) recorded at different time intervals. In this method, sharp-image ROI recovery is indispensable to compensate for displacements of the cell cultures due either to the exploration of multiple sites of the same culture or to transfers from the microscope stage to a cell incubator. ROI recovery is usually done manually and, despite a low-magnification microscope objective is generally used (10x), repositioning imperfections constitute a major source of errors detrimental to the WR measurement accuracy. We address this ROI recovery issue by using pseudoperiodic patterns fixed onto the cell culture dishes, allowing the easy localization of ROIs and the accurate quantification of positioning errors. The method is applied to a tumor-derived cell line, and the WR rates are measured by means of two different image processing software. Sharp ROI recovery based on the proposed method is found to improve significantly the accuracy of the WR measurement and the positioning under the microscope.

  7. Improving accuracy of rare variant imputation with a two-step imputation approach

    DEFF Research Database (Denmark)

    Kreiner-Møller, Eskil; Medina-Gomez, Carolina; Uitterlinden, André G

    2015-01-01

    not being comprehensively scrutinized. Next-generation arrays ensuring sufficient coverage together with new reference panels, as the 1000 Genomes panel, are emerging to facilitate imputation of low frequent single-nucleotide polymorphisms (minor allele frequency (MAF) two-step......, the concordance rate between calls of imputed and true genotypes was found to be significantly higher for heterozygotes (Ptwo-step approach in our setting improves imputation quality compared with traditional direct imputation noteworthy...

  8. Improving nuclear data accuracy of 241Am and 237Np capture cross sections

    Science.gov (United States)

    Žerovnik, Gašper; Schillebeeckx, Peter; Cano-Ott, Daniel; Jandel, Marian; Hori, Jun-ichi; Kimura, Atsushi; Rossbach, Matthias; Letourneau, Alain; Noguere, Gilles; Leconte, Pierre; Sano, Tadafumi; Kellett, Mark A.; Iwamoto, Osamu; Ignatyuk, Anatoly V.; Cabellos, Oscar; Genreith, Christoph; Harada, Hideo

    2017-09-01

    In the framework of the OECD/NEA WPEC subgroup 41, ways to improve neutron induced capture cross sections for 241Am and 237Np are being sought. Decay data, energy dependent cross section data and neutron spectrum averaged data are important for that purpose and were investigated. New time-of-flight measurements were performed and analyzed, and considerable effort was put into development of methods for analysis of spectrum averaged data and re-analysis of existing experimental data.

  9. Assimilating aircraft-based measurements to improve forecast accuracy of volcanic ash transport

    Science.gov (United States)

    Fu, G.; Lin, H. X.; Heemink, A. W.; Segers, A. J.; Lu, S.; Palsson, T.

    2015-08-01

    The 2010 Eyjafjallajökull volcano eruption had serious consequences to civil aviation. This has initiated a lot of research on volcanic ash transport forecast in recent years. For forecasting the volcanic ash transport after eruption onset, a volcanic ash transport and diffusion model (VATDM) needs to be run with Eruption Source Parameters (ESP) such as plume height and mass eruption rate as input, and with data assimilation techniques to continuously improve the initial conditions of the forecast. Reliable and accurate ash measurements are crucial for providing a successful ash clouds advice. In this paper, simulated aircraft-based measurements, as one type of volcanic ash measurements, will be assimilated into a transport model to identify the potential benefit of this kind of observations in an assimilation system. The results show assimilating aircraft-based measurements can significantly improve the state of ash clouds, and further providing an improved forecast as aviation advice. We also show that for advice of aeroplane flying level, aircraft-based measurements should be preferably taken from this level to obtain the best performance on it. Furthermore it is shown that in order to make an acceptable advice for aviation decision makers, accurate knowledge about uncertainties of ESPs and measurements is of great importance.

  10. EpCAM-based flow cytometry in cerebrospinal fluid greatly improves diagnostic accuracy of leptomeningeal metastases from epithelial tumors

    Science.gov (United States)

    Milojkovic Kerklaan, Bojana; Pluim, Dick; Bol, Mijke; Hofland, Ingrid; Westerga, Johan; van Tinteren, Harm; Beijnen, Jos H.; Boogerd, Willem; Schellens, Jan H. M.; Brandsma, Dieta

    2016-01-01

    Background Moderate diagnostic accuracy of MRI and initial cerebrospinal fluid (CSF) cytology analysis results in at least 10%–15% false negative diagnoses of leptomeningeal metastases (LM) of solid tumors, thus postponing start of therapy. The aim of this prospective clinical study was to determine the diagnostic value of epithelial cell adhesion molecule (EpCAM)–based flow cytometry versus cytology in CSF for the diagnosis of LM in patients with epithelial tumors. Methods Patients with a clinical suspicion of LM but a negative or inconclusive MRI in whom a diagnostic lumbar puncture has to be performed were included. At least 5 mL of CSF for cytology, 5 mL for flow cytometry, 2 mL for cell count and biochemistry, and 8 mL whole blood samples for circulating tumor cells measurements and biochemistry were drawn. Tumor cells in CSF and whole blood were detected by multiparameter flow cytometry using EpCAM antibody. Results In total 29 eligible patients were enrolled in the study. Thirteen patients were ultimately diagnosed with LM. The flow cytometry assay showed 100% sensitivity and 100% specificity for diagnosing LM, while sensitivity of CSF cytology was only 61.5%. Cell count or biochemical parameters in CSF were abnormal in 100% of patients with LM. Conclusions Our results suggest that the EpCAM-based flow cytometry assay is superior to CSF cytology for the diagnosis of LM in patients with an epithelial tumor, a clinical suspicion of LM, and a nonconclusive MRI. Confirmation of these data is needed in a larger dataset to recommend dual CSF diagnostics for LM. ClinicalTrials.gov Identifier NCT01713699. PMID:26566655

  11. An improved multivariate analytical method to assess the accuracy of acoustic sediment classification maps.

    Science.gov (United States)

    Biondo, M.; Bartholomä, A.

    2014-12-01

    High resolution hydro acoustic methods have been successfully employed for the detailed classification of sedimentary habitats. The fine-scale mapping of very heterogeneous, patchy sedimentary facies, and the compound effect of multiple non-linear physical processes on the acoustic signal, cause the classification of backscatter images to be subject to a great level of uncertainty. Standard procedures for assessing the accuracy of acoustic classification maps are not yet established. This study applies different statistical techniques to automated classified acoustic images with the aim of i) quantifying the ability of backscatter to resolve grain size distributions ii) understanding complex patterns influenced by factors other than grain size variations iii) designing innovative repeatable statistical procedures to spatially assess classification uncertainties. A high-frequency (450 kHz) sidescan sonar survey, carried out in the year 2012 in the shallow upper-mesotidal inlet the Jade Bay (German North Sea), allowed to map 100 km2 of surficial sediment with a resolution and coverage never acquired before in the area. The backscatter mosaic was ground-truthed using a large dataset of sediment grab sample information (2009-2011). Multivariate procedures were employed for modelling the relationship between acoustic descriptors and granulometric variables in order to evaluate the correctness of acoustic classes allocation and sediment group separation. Complex patterns in the acoustic signal appeared to be controlled by the combined effect of surface roughness, sorting and mean grain size variations. The area is dominated by silt and fine sand in very mixed compositions; in this fine grained matrix, percentages of gravel resulted to be the prevailing factor affecting backscatter variability. In the absence of coarse material, sorting mostly affected the ability to detect gradual but significant changes in seabed types. Misclassification due to temporal discrepancies

  12. Improvements and Variants of the Multiple Antigen Blot Assay-MABA: An Immunoenzymatic Technique for Simultaneous Antigen and Antibody Screening.

    Science.gov (United States)

    Noya, Oscar; Losada, Sandra; Toledo, Marilyan; Gauna, Adriana; Lorenzo, María Angelita; Bermúdez, Henry; de Noya, Belkisyolé Alarcón

    2015-01-01

    This simple, versatile, reliable, reproducible, multipurpose, and inexpensive technique is based on the adhesion of different antigens to a single nitrocellulose strip using, as template, an acrylic device containing 28 parallel channels. The inclusion of channels containing normal human serum improves the quality control of this assay. Antigen-sensitized nitrocellulose strips are cut perpendicularly to the antigen-rows, exposed to immune sera followed by the appropriate conjugate. Positive signals are recorded using chemiluminescent or precipitable colorimetric substrates. This assay allows the simultaneous qualitative demonstration of antigenicity and immunogenicity of antigens obtained as synthetic peptides, recombinant molecules, or crude preparations, with high sensitivity and specificity. Its major value is based on the rapid and simultaneous comparative evaluation of various antigenic preparations allowing the diagnosis of a variety of infectious, allergic, and autoimmune diseases. It can in general be used to detect any type of antibody or circulating antigen. Some improvements and variants of the original technique are included.

  13. Devices, systems, and methods for conducting assays with improved sensitivity using sedimentation

    Science.gov (United States)

    Schaff, Ulrich Y; Koh, Chung-Yan; Sommer, Gregory J

    2015-02-24

    Embodiments of the present invention are directed toward devices, systems, and method for conducting assays using sedimentation. In one example, a method includes layering a mixture on a density medium, subjecting sedimentation particles in the mixture to sedimentation forces to cause the sedimentation particles to move to a detection area through a density medium, and detecting a target analyte in a detection region of the sedimentation channel. In some examples, the sedimentation particles and labeling agent may have like charges to reduce non-specific binding of labeling agent and sedimentation particles. In some examples, the density medium is provided with a separation layer for stabilizing the assay during storage and operation. In some examples, the sedimentation channel may be provided with a generally flat sedimentation chamber for dispersing the particle pellet over a larger surface area.

  14. Devices, systems, and methods for conducting assays with improved sensitivity using sedimentation

    Science.gov (United States)

    Schaff, Ulrich Y.; Koh, Chung-Yan; Sommer, Gregory J.

    2016-04-05

    Embodiments of the present invention are directed toward devices, systems, and method for conducting assays using sedimentation. In one example, a method includes layering a mixture on a density medium, subjecting sedimentation particles in the mixture to sedimentation forces to cause the sedimentation particles to move to a detection area through a density medium, and detecting a target analyte in a detection region of the sedimentation channel. In some examples, the sedimentation particles and labeling agent may have like charges to reduce non-specific binding of labeling agent and sedimentation particles. In some examples, the density medium is provided with a separation layer for stabilizing the assay during storage and operation. In some examples, the sedimentation channel may be provided with a generally flat sedimentation chamber for dispersing the particle pellet over a larger surface area.

  15. An improved 96-well turbidity assay for T4 lysozyme activity

    Science.gov (United States)

    2015-05-13

    room temperature, according to the manufacturer’s instructions. 4. Wash resin twice with 10 bed volumes of wash buffer (30mM potassium phosphate pH...measurements for T4L. First, the 30minute time allowance between cell suspension and the start of the assay was optimal for cells to rehydrate and settle...Determination of lysozyme activities in a microplate format, Anal. Biochem. 310 (2002) 223–224. [3] D. Christybapita, M. Divyagnaneswari, R.D. Michael, Oral

  16. Dissolution Behavior and Content Uniformity of An Improved Tablet Formulation Assayed by Spectrofluorometric and RIA Methods

    Directory of Open Access Journals (Sweden)

    Morteza Rafiee-Tehrani

    1990-06-01

    Full Text Available Digoxin 0.25 mg tablets were manufactured by pregranulation of lactose-fcorn starch with 10% corn starch paste and deposition of solvent on pregranules to make digoxin granules. In the preparation of tablet A, granules of lactose-corn Starch was uniformly moistened with a 5% chloroform-ethanol solution (2:lv/vof digoxin by a simple blending. Tablet B was produced by spray granulation system on which the solvent was sprayed on the granules of lactose-corn starch by utilization of a laboratory size fluidized bed drier (Uniglatt . The content uniformity and dissolution of both tablets were determined by the spectrofluorometric and radio¬immunoassay (RIA method modified for the assay of tablet solutious. One available commercially brand of digoxin tablet (C was included in dissolution study for comparison. For the spectrofluorometric method the technique is based on the fluor-ometric measurenent of the dehydration product of the cardiotonic steroid resulting from its reaction with hydrogen peroxide in concentrated hydrochloric acid. For the RIA method, the filtrate was diluted to theoretical concentration of 2.5 ng/ml."nAliquots of this dilution were then assayed for digoxin content using a commercial digoxin125 I RIA kit. Results from both assay methods were extrapolated to the total tablet content and compared with the labeled amount of 20 individual tablets. All tablet assay results were within the USP standards for the content uniformity and"ndissolution of individual. The individual tablet deviations from labeled amount by RIA method were smaller when compared with the spectrofluorometric method.There was no significant difference between the release of digoxin from three products, and thus it is suggested that the Procedure B could be easily applied for manufacturing"nof digoxin tablets in industrial scales.It was also concluded that,the RIA method could be used for the digoxin tablet determination.

  17. Evaluation of improved IS6110 LAMP assay for diagnosis of pulmonary and extra pulmonary tuberculosis.

    Science.gov (United States)

    Joon, Deepali; Nimesh, Manoj; Varma-Basil, Mandira; Saluja, Daman

    2017-08-01

    In the present study, IS6110 loop mediated isothermal amplification (LAMP) assay was modified using dUTP-UNG (uracil-DNA N-glycosylase) strategy to prevent carryover contamination, and was evaluated using clinical specimens. The clinical specimens were collected from 236 suspected patients of pulmonary tuberculosis and 315 specimens of suspected patients of extra pulmonary tuberculosis. DNA was extracted from specimens and used as template for nucleic acid amplification. The results were evaluated with culture method as gold standard. Modified IS6110 LAMP assay showed high sensitivity (94.4%) and specificity (97.2%) in specimens collected from suspected pulmonary tuberculosis patients. Sensitivity was comparatively less (86.67%) in extra pulmonary specimens while specificity was 94.04%. In conclusion, IS6110 LAMP assay was modified to prevent carry over contamination and it was validated to be rapid, sensitive and specific method with prospective application in resource-limited settings. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Strategies to Improve the Accuracy of Mars-GRAM Sensitivity Studies at Large Optical Depths

    Science.gov (United States)

    Justh, Hilary L.; Justus, Carl G.; Badger, Andrew M.

    2010-01-01

    The poster provides an overview of techniques to improve the Mars Global Reference Atmospheric Model (Mars-GRAM) sensitivity. It has been discovered during the Mars Science Laboratory (MSL) site selection process that the Mars Global Reference Atmospheric Model (Mars-GRAM) when used for sensitivity studies for TES MapYear = 0 and large optical depth values such as tau = 3 is less than realistic. A preliminary fix has been made to Mars-GRAM by adding a density factor value that was determined for tau = 0.3, 1 and 3.

  19. Stratification by Genetic and Demographic Characteristics Improves Diagnostic Accuracy of Cerebrospinal Fluid Biomarkers in Rapidly Progressive Dementia.

    Science.gov (United States)

    Karch, André; Llorens, Franc; Schmitz, Matthias; Arora, Amandeep Singh; Zafar, Saima; Lange, Peter; Schmidt, Christian; Zerr, Inga

    2016-10-18

    Cerebrospinal fluid (CSF) biomarkers are routinely used for the differential diagnosis of rapidly progressive dementia, but are also affected by patients' characteristics. To assess if stratification by age, sex, and genetic risk factors improves the accuracy of cerebrospinal fluid (CSF) biomarkers in patients with rapidly progressive dementia. 1,538 individuals with sporadic Creutzfeldt-Jakob disease (CJD), 173 with classic Alzheimer's disease (cAD), 37 with rapidly progressive Alzheimer's disease (rpAD), and 589 without signs of dementia were included in this retrospective diagnostic study. The effect of age, sex, PRNP codon 129, and APOE genotype on CSF levels of tau, p-tau, Aβ1-42, and Aβ1-40 values measured at time of diagnostic work-up was assessed. Tau was a better marker for the differentiation of CJD and rpAD in older (AUC:0.97; 95% CI:0.96-1.00) than in younger (AUC:0.91; 95% CI:0.87-0.94) patients as tau levels increased with age in CJD patients, but not in rpAD patients. PRNP codon 129 and APOE genotype had complex effects on biomarkers in all diseases, making stratification by genotype a powerful tool. In females (AUC:0.78; 95% CI:0.65-0.91) and patients older than 70 (AUC:0.78; 95% CI:0.62-0.93), tau was able to differentiate with moderate accuracy between cAD and rpAD patients. Implementation of stratum-specific reference ranges improves the diagnostic accuracy of CSF biomarkers for the differential diagnosis of rapidly progressive dementia. Diagnostic criteria developed for this setting have to take this into account.

  20. A Simple and Efficient Methodology To Improve Geometric Accuracy in Gamma Knife Radiation Surgery: Implementation in Multiple Brain Metastases

    Energy Technology Data Exchange (ETDEWEB)

    Karaiskos, Pantelis, E-mail: pkaraisk@med.uoa.gr [Medical Physics Laboratory, Medical School, University of Athens (Greece); Gamma Knife Department, Hygeia Hospital, Athens (Greece); Moutsatsos, Argyris; Pappas, Eleftherios; Georgiou, Evangelos [Medical Physics Laboratory, Medical School, University of Athens (Greece); Roussakis, Arkadios [CT and MRI Department, Hygeia Hospital, Athens (Greece); Torrens, Michael [Gamma Knife Department, Hygeia Hospital, Athens (Greece); Seimenis, Ioannis [Medical Physics Laboratory, Medical School, Democritus University of Thrace, Alexandroupolis (Greece)

    2014-12-01

    Purpose: To propose, verify, and implement a simple and efficient methodology for the improvement of total geometric accuracy in multiple brain metastases gamma knife (GK) radiation surgery. Methods and Materials: The proposed methodology exploits the directional dependence of magnetic resonance imaging (MRI)-related spatial distortions stemming from background field inhomogeneities, also known as sequence-dependent distortions, with respect to the read-gradient polarity during MRI acquisition. First, an extra MRI pulse sequence is acquired with the same imaging parameters as those used for routine patient imaging, aside from a reversal in the read-gradient polarity. Then, “average” image data are compounded from data acquired from the 2 MRI sequences and are used for treatment planning purposes. The method was applied and verified in a polymer gel phantom irradiated with multiple shots in an extended region of the GK stereotactic space. Its clinical impact in dose delivery accuracy was assessed in 15 patients with a total of 96 relatively small (<2 cm) metastases treated with GK radiation surgery. Results: Phantom study results showed that use of average MR images eliminates the effect of sequence-dependent distortions, leading to a total spatial uncertainty of less than 0.3 mm, attributed mainly to gradient nonlinearities. In brain metastases patients, non-eliminated sequence-dependent distortions lead to target localization uncertainties of up to 1.3 mm (mean: 0.51 ± 0.37 mm) with respect to the corresponding target locations in the “average” MRI series. Due to these uncertainties, a considerable underdosage (5%-32% of the prescription dose) was found in 33% of the studied targets. Conclusions: The proposed methodology is simple and straightforward in its implementation. Regarding multiple brain metastases applications, the suggested approach may substantially improve total GK dose delivery accuracy in smaller, outlying targets.

  1. "Score the Core" Web-based pathologist training tool improves the accuracy of breast cancer IHC4 scoring.

    Science.gov (United States)

    Engelberg, Jesse A; Retallack, Hanna; Balassanian, Ronald; Dowsett, Mitchell; Zabaglo, Lila; Ram, Arishneel A; Apple, Sophia K; Bishop, John W; Borowsky, Alexander D; Carpenter, Philip M; Chen, Yunn-Yi; Datnow, Brian; Elson, Sarah; Hasteh, Farnaz; Lin, Fritz; Moatamed, Neda A; Zhang, Yanhong; Cardiff, Robert D

    2015-11-01

    Hormone receptor status is an integral component of decision-making in breast cancer management. IHC4 score is an algorithm that combines hormone receptor, HER2, and Ki-67 status to provide a semiquantitative prognostic score for breast cancer. High accuracy and low interobserver variance are important to ensure the score is accurately calculated; however, few previous efforts have been made to measure or decrease interobserver variance. We developed a Web-based training tool, called "Score the Core" (STC) using tissue microarrays to train pathologists to visually score estrogen receptor (using the 300-point H score), progesterone receptor (percent positive), and Ki-67 (percent positive). STC used a reference score calculated from a reproducible manual counting method. Pathologists in the Athena Breast Health Network and pathology residents at associated institutions completed the exercise. By using STC, pathologists improved their estrogen receptor H score and progesterone receptor and Ki-67 proportion assessment and demonstrated a good correlation between pathologist and reference scores. In addition, we collected information about pathologist performance that allowed us to compare individual pathologists and measures of agreement. Pathologists' assessment of the proportion of positive cells was closer to the reference than their assessment of the relative intensity of positive cells. Careful training and assessment should be used to ensure the accuracy of breast biomarkers. This is particularly important as breast cancer diagnostics become increasingly quantitative and reproducible. Our training tool is a novel approach for pathologist training that can serve as an important component of ongoing quality assessment and can improve the accuracy of breast cancer prognostic biomarkers. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Improved accuracy of markerless motion tracking on bone suppression images: preliminary study for image-guided radiation therapy (IGRT)

    Science.gov (United States)

    Tanaka, Rie; Sanada, Shigeru; Sakuta, Keita; Kawashima, Hiroki

    2015-05-01

    The bone suppression technique based on advanced image processing can suppress the conspicuity of bones on chest radiographs, creating soft tissue images obtained by the dual-energy subtraction technique. This study was performed to evaluate the usefulness of bone suppression image processing in image-guided radiation therapy. We demonstrated the improved accuracy of markerless motion tracking on bone suppression images. Chest fluoroscopic images of nine patients with lung nodules during respiration were obtained using a flat-panel detector system (120 kV, 0.1 mAs/pulse, 5 fps). Commercial bone suppression image processing software was applied to the fluoroscopic images to create corresponding bone suppression images. Regions of interest were manually located on lung nodules and automatic target tracking was conducted based on the template matching technique. To evaluate the accuracy of target tracking, the maximum tracking error in the resulting images was compared with that of conventional fluoroscopic images. The tracking errors were decreased by half in eight of nine cases. The average maximum tracking errors in bone suppression and conventional fluoroscopic images were 1.3   ±   1.0 and 3.3   ±   3.3 mm, respectively. The bone suppression technique was especially effective in the lower lung area where pulmonary vessels, bronchi, and ribs showed complex movements. The bone suppression technique improved tracking accuracy without special equipment and implantation of fiducial markers, and with only additional small dose to the patient. Bone suppression fluoroscopy is a potential measure for respiratory displacement of the target. This paper was presented at RSNA 2013 and was carried out at Kanazawa University, JAPAN.

  3. IMPROVING THE GRAMMATICAL ACCURACY OF THE SPOKEN ENGLISH OF INDONESIAN INTERNATIONAL KINDERGARTEN STUDENTS

    Directory of Open Access Journals (Sweden)

    IMELDA GOZALI

    2014-07-01

    Full Text Available The need to improve the spoken English of kindergarten students in an international preschool in Surabaya prompted this Classroom Action Research (CAR. It involved the implementation of Form-Focused Instruction (FFI strategy coupled with Corrective Feedback (CF in Grammar lessons. Four grammar topics were selected, namely Regular Plural form, Subject Pronoun, Auxiliary Verbs Do/Does, and Irregular Past Tense Verbs as they were deemed to be the morpho-syntax which children acquire early in life based on the order of acquisition in Second Language Acquisition. The results showed that FFI and CF contributed to the improvement of the spoken grammar in varying degrees, depending on the academic performance, personality, and specific linguistic traits of the students. Students with high academic achievement could generally apply the grammar points taught after the FFI lessons in their daily speech. Students who were rather talkative were sensitive to the CF and could provide self-repair when prompted. Those with lower academic performance generally did not benefit much from the FFI lessons nor the CF.

  4. A New Multi-Sensor Fusion Scheme to Improve the Accuracy of Knee Flexion Kinematics for Functional Rehabilitation Movements

    Directory of Open Access Journals (Sweden)

    Halim Tannous

    2016-11-01

    Full Text Available Exergames have been proposed as a potential tool to improve the current practice of musculoskeletal rehabilitation. Inertial or optical motion capture sensors are commonly used to track the subject’s movements. However, the use of these motion capture tools suffers from the lack of accuracy in estimating joint angles, which could lead to wrong data interpretation. In this study, we proposed a real time quaternion-based fusion scheme, based on the extended Kalman filter, between inertial and visual motion capture sensors, to improve the estimation accuracy of joint angles. The fusion outcome was compared to angles measured using a goniometer. The fusion output shows a better estimation, when compared to inertial measurement units and Kinect outputs. We noted a smaller error (3.96° compared to the one obtained using inertial sensors (5.04°. The proposed multi-sensor fusion system is therefore accurate enough to be applied, in future works, to our serious game for musculoskeletal rehabilitation.

  5. Audiovisual communication of object-names improves the spatial accuracy of recalled object-locations in topographic maps.

    Science.gov (United States)

    Lammert-Siepmann, Nils; Bestgen, Anne-Kathrin; Edler, Dennis; Kuchinke, Lars; Dickmann, Frank

    2017-01-01

    Knowing the correct location of a specific object learned from a (topographic) map is fundamental for orientation and navigation tasks. Spatial reference systems, such as coordinates or cardinal directions, are helpful tools for any geometric localization of positions that aims to be as exact as possible. Considering modern visualization techniques of multimedia cartography, map elements transferred through the auditory channel can be added easily. Audiovisual approaches have been discussed in the cartographic community for many years. However, the effectiveness of audiovisual map elements for map use has hardly been explored so far. Within an interdisciplinary (cartography-cognitive psychology) research project, it is examined whether map users remember object-locations better if they do not just read the corresponding place names, but also listen to them as voice recordings. This approach is based on the idea that learning object-identities influences learning object-locations, which is crucial for map-reading tasks. The results of an empirical study show that the additional auditory communication of object names not only improves memory for the names (object-identities), but also for the spatial accuracy of their corresponding object-locations. The audiovisual communication of semantic attribute information of a spatial object seems to improve the binding of object-identity and object-location, which enhances the spatial accuracy of object-location memory.

  6. Audiovisual communication of object-names improves the spatial accuracy of recalled object-locations in topographic maps.

    Directory of Open Access Journals (Sweden)

    Nils Lammert-Siepmann

    Full Text Available Knowing the correct location of a specific object learned from a (topographic map is fundamental for orientation and navigation tasks. Spatial reference systems, such as coordinates or cardinal directions, are helpful tools for any geometric localization of positions that aims to be as exact as possible. Considering modern visualization techniques of multimedia cartography, map elements transferred through the auditory channel can be added easily. Audiovisual approaches have been discussed in the cartographic community for many years. However, the effectiveness of audiovisual map elements for map use has hardly been explored so far. Within an interdisciplinary (cartography-cognitive psychology research project, it is examined whether map users remember object-locations better if they do not just read the corresponding place names, but also listen to them as voice recordings. This approach is based on the idea that learning object-identities influences learning object-locations, which is crucial for map-reading tasks. The results of an empirical study show that the additional auditory communication of object names not only improves memory for the names (object-identities, but also for the spatial accuracy of their corresponding object-locations. The audiovisual communication of semantic attribute information of a spatial object seems to improve the binding of object-identity and object-location, which enhances the spatial accuracy of object-location memory.

  7. Brute force meets Bruno force in parameter optimisation: introduction of novel constraints for parameter accuracy improvement by symbolic computation.

    Science.gov (United States)

    Nakatsui, M; Horimoto, K; Lemaire, F; Ürgüplü, A; Sedoglavic, A; Boulier, F

    2011-09-01

    Recent remarkable advances in computer performance have enabled us to estimate parameter values by the huge power of numerical computation, the so-called 'Brute force', resulting in the high-speed simultaneous estimation of a large number of parameter values. However, these advancements have not been fully utilised to improve the accuracy of parameter estimation. Here the authors review a novel method for parameter estimation using symbolic computation power, 'Bruno force', named after Bruno Buchberger, who found the Gröbner base. In the method, the objective functions combining the symbolic computation techniques are formulated. First, the authors utilise a symbolic computation technique, differential elimination, which symbolically reduces an equivalent system of differential equations to a system in a given model. Second, since its equivalent system is frequently composed of large equations, the system is further simplified by another symbolic computation. The performance of the authors' method for parameter accuracy improvement is illustrated by two representative models in biology, a simple cascade model and a negative feedback model in comparison with the previous numerical methods. Finally, the limits and extensions of the authors' method are discussed, in terms of the possible power of 'Bruno force' for the development of a new horizon in parameter estimation.

  8. Improving the Accuracy of Coastal Sea Surface Heights by Retracking Decontaminated Radar Altimetry Waveforms

    Science.gov (United States)

    Huang, Zhengkai; Wang, Haihong; Luo, Zhicai

    2017-04-01

    Due to the complex coastal topography and energetic ocean dynamics effect, the return echoes are contaminated while the satellite footprint approaches or leaves the coastline. Specular peaks are often induced in the trailing edges of contaminated waveforms, thus leading the error in the determination of the leading edge and associated track offset in the waveform retracking process. We propose an improved algorithm base on Tseng's modification method to decontaminated coastal (0-7 km from coastline) waveforms, thus improving both the utilization and precision of coastal sea surface height (SSH). Using the Envisat/Jason-2 SGDR data, the shortcoming of Tseng's method is pointed out and the novel algorithm is proposed by revising the strategy of selecting reference waveform and determining weight for removing outlier. The reference waveform of the decontaminated technology is closer to the real waveform of the offshore area, which avoids the over-modification problem of Tseng method. The sea-level measurements from tide gauge station and geoid height from EGM2008 model were used to validate the retracking strategy. Experimental results show that decontaminated waveform was more suitable than original and Tseng modified waveform and has uniform performance in both compare to the tide gauge and geoid. The retrieved altimetry data in the 0-1km and 1-7km coastal zone indicate that threshold retracker with decontaminated waveform have STD of 73.8cm and 33cm as compared with in situ gauge data,which correspond to 62.1% and 58% in precession compared to the unretracked altimetry measurements. The retracked SSHs are better in two coastal (0-1 km and 1-7km) zones, which have STD of 11.9cm and 22.7cm as compared with geoid height. Furthermore, the comparisons shows that the precision of decontaminated technology improve 0.3cm and 3.3cm than the best result of PISTACH product in coastal sea. This work is supported by the National Natural Science Foundation of China (Grant Nos

  9. Decentralised control method for DC microgrids with improved current sharing accuracy

    DEFF Research Database (Denmark)

    Yang, Jie; Jin, Xinmin; Wu, Xuezhi

    2017-01-01

    A decentralised control method that deals with current sharing issues in dc microgrids (MGs) is proposed in this study. The proposed method is formulated in terms of ‘modified global indicator’ concept, which was originally proposed to improve reactive power sharing in ac MGs. In this work......, the ‘modified global indicator’ concept is extended to coordinate dc MGs, which aims to preserve the main features offered by decentralised control methods such as no need of communication links, central controller or knowledge of the microgrid topology and parameters. This global indicator is inserted between...... a shunt virtual resistance. The operation under multiple dc-buses is also included in order to enhance the applicability of the proposed controller. A detailed mathematical model including the effect of network mismatches is derived for analysis of the stability of the proposed controller. The feasibility...

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

    Science.gov (United States)

    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.

  11. Improving ECG classification accuracy using an ensemble of neural network modules.

    Directory of Open Access Journals (Sweden)

    Mehrdad Javadi

    Full Text Available This paper illustrates the use of a combined neural network model based on Stacked Generalization method for classification of electrocardiogram (ECG beats. In conventional Stacked Generalization method, the combiner learns to map the base classifiers' outputs to the target data. We claim adding the input pattern to the base classifiers' outputs helps the combiner to obtain knowledge about the input space and as the result, performs better on the same task. Experimental results support our claim that the additional knowledge according to the input space, improves the performance of the proposed method which is called Modified Stacked Generalization. In particular, for classification of 14966 ECG beats that were not previously seen during training phase, the Modified Stacked Generalization method reduced the error rate for 12.41% in comparison with the best of ten popular classifier fusion methods including Max, Min, Average, Product, Majority Voting, Borda Count, Decision Templates, Weighted Averaging based on Particle Swarm Optimization and Stacked Generalization.

  12. Improving the accuracy: volatility modeling and forecasting using high-frequency data and the variational component

    Directory of Open Access Journals (Sweden)

    Manish Kumar

    2010-06-01

    Full Text Available In this study, we predict the daily volatility of the S&P CNX NIFTY market index of India using the basic ‘heterogeneous autoregressive’ (HAR and its variant. In doing so, we estimated several HAR and Log form of HAR models using different regressor. The different regressors were obtained by extracting the jump and continuous component and the threshold jump and continuous component from the realized volatility. We also tried to investigate whether dividing volatility into simple and threshold jumps and continuous variation yields a substantial improvement in volatility forecasting or not. The results provide the evidence that inclusion of realized bipower variance in the HAR models helps in predicting future volatility.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Junga Hwang

    2016-12-01

    Full Text Available 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.

  15. Improving the Accuracy of Baha® Fittings through Measures of Direct Bone Conduction

    Science.gov (United States)

    Hillbratt, Martin

    2012-01-01

    Objectives Variability in Baha® sound processor fittings may arise from the nature of the implant-to-bone transmission as well as transcranial attenuation for patients with single-sided sensorineural deafness (SSD). One method of improving the predictability of Baha fittings is to measure the individual patient's actual bone conduction thresholds, thereby removing the influences of skin thickness and/or the implant location site. Methods Twenty adult wearers of the Baha bone conduction implant system participated in the study. Direct bone conduction thresholds were obtained through the BC Direct function of the Baha Fitting Software combined with the Cochlear Baha BP100 sound processor. For comparison, the masked and unmasked bone conduction responses of the patients were collected through standard audiometric testing techniques. Test-retest reliability measurement was performed for all participants. Data for each frequency and frequency range were analyzed separately. Results The results confirm the improved transmission of sound through the implant rather than transcutaneously through the skin. On average, the BC Direct thresholds were closer to the patient's unmasked thresholds than the masked values. In subjects with SSD, BC Direct results were poorer than contra-lateral bone conduction thresholds, most likely due to transcranial attenuation. The test-retest reliability for the BC Direct measurements was within +/-5 dB. The comparison of preferred amplification, based on direct bone conduction or bone conduction audiometry, found higher agreement for fittings based on direct bone conduction measurements. Conclusion While the transfer function between the implant and the skin can be predicted on average, there are a number of patients for whom measurement is essential to determine the required amplification. These were patients with: 1) SSD, 2) asymmetrical hearing loss, 3) unusual implant location or skull formation, and 4) users of Testband or Softband. The

  16. A multidisciplinary approach to vascular surgery procedure coding improves coding accuracy, work relative value unit assignment, and reimbursement.

    Science.gov (United States)

    Aiello, Francesco A; Judelson, Dejah R; Messina, Louis M; Indes, Jeffrey; FitzGerald, Gordon; Doucet, Danielle R; Simons, Jessica P; Schanzer, Andres

    2016-08-01

    Vascular surgery procedural reimbursement depends on accurate procedural coding and documentation. Despite the critical importance of correct coding, there has been a paucity of research focused on the effect of direct physician involvement. We hypothesize that direct physician involvement in procedural coding will lead to improved coding accuracy, increased work relative value unit (wRVU) assignment, and increased physician reimbursement. This prospective observational cohort study evaluated procedural coding accuracy of fistulograms at an academic medical institution (January-June 2014). All fistulograms were coded by institutional coders (traditional coding) and by a single vascular surgeon whose codes were verified by two institution coders (multidisciplinary coding). The coding methods were compared, and differences were translated into revenue and wRVUs using the Medicare Physician Fee Schedule. Comparison between traditional and multidisciplinary coding was performed for three discrete study periods: baseline (period 1), after a coding education session for physicians and coders (period 2), and after a coding education session with implementation of an operative dictation template (period 3). The accuracy of surgeon operative dictations during each study period was also assessed. An external validation at a second academic institution was performed during period 1 to assess and compare coding accuracy. During period 1, traditional coding resulted in a 4.4% (P = .004) loss in reimbursement and a 5.4% (P = .01) loss in wRVUs compared with multidisciplinary coding. During period 2, no significant difference was found between traditional and multidisciplinary coding in reimbursement (1.3% loss; P = .24) or wRVUs (1.8% loss; P = .20). During period 3, traditional coding yielded a higher overall reimbursement (1.3% gain; P = .26) than multidisciplinary coding. This increase, however, was due to errors by institution coders, with six inappropriately used codes

  17. A patient-centered methodology that improves the accuracy of prognostic predictions in cancer.

    Directory of Open Access Journals (Sweden)

    Mohammed Kashani-Sabet

    Full Text Available Individualized approaches to prognosis are crucial to effective management of cancer patients. We developed a methodology to assign individualized 5-year disease-specific death probabilities to 1,222 patients with melanoma and to 1,225 patients with breast cancer. For each cancer, three risk subgroups were identified by stratifying patients according to initial stage, and prediction probabilities were generated based on the factors most closely related to 5-year disease-specific death. Separate subgroup probabilities were merged to form a single composite index, and its predictive efficacy was assessed by several measures, including the area (AUC under its receiver operating characteristic (ROC curve. The patient-centered methodology achieved an AUC of 0.867 in the prediction of 5-year disease-specific death, compared with 0.787 using the AJCC staging classification alone. When applied to breast cancer patients, it achieved an AUC of 0.907, compared with 0.802 using the AJCC staging classification alone. A prognostic algorithm produced from a randomly selected training subsample of 800 melanoma patients preserved 92.5% of its prognostic efficacy (as measured by AUC when the same algorithm was applied to a validation subsample containing the remaining patients. Finally, the tailored prognostic approach enhanced the identification of high-risk candidates for adjuvant therapy in melanoma. These results describe a novel patient-centered prognostic methodology with improved predictive efficacy when compared with AJCC stage alone in two distinct malignancies drawn from two separate populations.

  18. Radiotherapy dosimetry audit: three decades of improving standards and accuracy in UK clinical practice and trials.

    Science.gov (United States)

    Clark, Catharine H; Aird, Edwin G A; Bolton, Steve; Miles, Elizabeth A; Nisbet, Andrew; Snaith, Julia A D; Thomas, Russell A S; Venables, Karen; Thwaites, David I

    2015-01-01

    Dosimetry audit plays an important role in the development and safety of radiotherapy. National and large scale audits are able to set, maintain and improve standards, as well as having the potential to identify issues which may cause harm to patients. They can support implementation of complex techniques and can facilitate awareness and understanding of any issues which may exist by benchmarking centres with similar equipment. This review examines the development of dosimetry audit in the UK over the past 30 years, including the involvement of the UK in international audits. A summary of audit results is given, with an overview of methodologies employed and lessons learnt. Recent and forthcoming more complex audits are considered, with a focus on future needs including the arrival of proton therapy in the UK and other advanced techniques such as four-dimensional radiotherapy delivery and verification, stereotactic radiotherapy and MR linear accelerators. The work of the main quality assurance and auditing bodies is discussed, including how they are working together to streamline audit and to ensure that all radiotherapy centres are involved. Undertaking regular external audit motivates centres to modernize and develop techniques and provides assurance, not only that radiotherapy is planned and delivered accurately but also that the patient dose delivered is as prescribed.

  19. Radiographic and anatomic basis for prostate contouring errors and methods to improve prostate contouring accuracy.

    Science.gov (United States)

    McLaughlin, Patrick W; Evans, Cheryl; Feng, Mary; Narayana, Vrinda

    2010-02-01

    Use of highly conformal radiation for prostate cancer can lead to both overtreatment of surrounding normal tissues and undertreatment of the prostate itself. In this retrospective study we analyzed the radiographic and anatomic basis of common errors in computed tomography (CT) contouring and suggest methods to correct them. Three hundred patients with prostate cancer underwent CT and magnetic resonance imaging (MRI). The prostate was delineated independently on the data sets. CT and MRI contours were compared by use of deformable registration. Errors in target delineation were analyzed and methods to avoid such errors detailed. Contouring errors were identified at the prostatic apex, mid gland, and base on CT. At the apex, the genitourinary diaphragm, rectum, and anterior fascia contribute to overestimation. At the mid prostate, the anterior and lateral fasciae contribute to overestimation. At the base, the bladder and anterior fascia contribute to anterior overestimation. Transition zone hypertrophy and bladder neck variability contribute to errors of overestimation and underestimation at the superior base, whereas variable prostate-to-seminal vesicle relationships with prostate hypertrophy contribute to contouring errors at the posterior base. Most CT contouring errors can be detected by (1) inspection of a lateral view of prostate contours to detect projection from the expected globular form and (2) recognition of anatomic structures (genitourinary diaphragm) on the CT scans that are clearly visible on MRI. This study shows that many CT prostate contouring errors can be improved without direct incorporation of MRI data. Copyright 2010 Elsevier Inc. All rights reserved.

  20. Improved Haptic Linear Lines for Better Movement Accuracy in Upper Limb Rehabilitation

    Directory of Open Access Journals (Sweden)

    Joan De Boeck

    2012-01-01

    Full Text Available Force feedback has proven to be beneficial in the domain of robot-assisted rehabilitation. According to the patients' personal needs, the generated forces may either be used to assist, support, or oppose their movements. In our current research project, we focus onto the upper limb training for MS (multiple sclerosis and CVA (cerebrovascular accident patients, in which a basic building block to implement many rehabilitation exercises was found. This building block is a haptic linear path: a second-order continuous path, defined by a list of points in space. Earlier, different attempts have been investigated to realize haptic linear paths. In order to have a good training quality, it is important that the haptic simulation is continuous up to the second derivative while the patient is enforced to follow the path tightly, even when low or no guiding forces are provided. In this paper, we describe our best solution to these haptic linear paths, discuss the weaknesses found in practice, and propose and validate an improvement.

  1. New procedure for improving precision and accuracy of instrumental color measurements of beef.

    Science.gov (United States)

    Khatri, Mamata; Phung, Vinh T; Isaksson, Tomas; Sørheim, Oddvin; Slinde, Erik; Egelandsdal, Bjørg

    2012-07-01

    The surface layers of steaks from bovine M. semimembranosus were prepared to have deoxy- (DMb), oxy- (OMb) and metmyoglobin (MMb) states using either chemicals (CHEM) or oxygen partial pressure packaging (OPP). Ninety-six different meat surface areas were measured in reflectance mode (400-1100 nm) for each preparation method. Reflectance spectra were converted to absorbance (A) and then transformed by Kubelka-Munk transformation (K/S) and/or extended multiplicative scatter correction (EMSC). Transformed spectra of prepared pure states were used to make calibration models of MMb, DMb and OMb using either selected wavelengths (SW) or partial least square (PLS) regression. Finally, the predicted myoglobin states were normalized to ensure that no state was 1 and the sum of all states equal to 1. Multivariate calibrations (i.e. PLS) outperformed the univariate calibrations (i.e. SW). The OPP method of preparing pure states was clearly best for OMb while the CHEM method was best for preparing MMb on fresh meat surfaces. Both preparation methods needed improvement concerning DMb. The CHEM(K/S) SW and the OPP EMSC(A) PLS methods predicted MMb, DMb and OMb with root-mean-square errors of cross validation (RMSECV) equal to 0.08, 0.16 and 0.18 (range 0-1) and 0.04, 0.04 and 0.04 (range 0-1), respectively. This new reflectance protocol has potential for routine meat color measurements. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Fetal MRI improves diagnostic accuracy in patients referred to a fetal center for suspected esophageal atresia.

    Science.gov (United States)

    Ethun, Cecilia G; Fallon, Sara C; Cassady, Christopher I; Mehollin-Ray, Amy R; Olutoye, Oluyinka O; Zamora, Irving J; Lee, Timothy C; Welty, Stephen E; Cass, Darrell L

    2014-05-01

    The purpose of this study was to describe prenatal imaging characteristics and outcomes of fetuses with suspected esophageal atresia (EA) in order to improve prenatal diagnosis, counseling, and management. The medical records of all patients referred to our multidisciplinary fetal center for suspected EA from January 2003 to April 2013 were reviewed retrospectively. Thirty-three patients were referred with a prenatal diagnosis of possible EA. Following fetal center evaluation with MRI, EA was deemed unlikely in 6 (18%) fetuses. Of 27 fetuses in whom EA could not be excluded, EA was confirmed postnatally in 15 (56%), excluded in 7 (26%), and unconfirmed in 5 (3 fetal losses; 2 lost to follow-up). Imaging characteristics on fetal MRI associated with the highest positive predictive values (PPV) were an esophageal pouch (100%) and a small stomach (75%). The finding of polyhydramnios had high sensitivity (93%) but low specificity (31%) and PPV (61%) for a diagnosis of EA. Prenatal imaging and fetal center evaluation correctly identify the presence or absence of esophageal atresia in 78% of patients referred on suspicion of this condition. The presence of an esophageal pouch on fetal MRI has significant predictive value for EA. These data may assist with evidence-based prenatal family counseling. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Improving the accuracy of the gradient method for determining soil carbon dioxide efflux

    Science.gov (United States)

    Sánchez-Cañete, Enrique P.; Scott, Russell L.; van Haren, Joost; Barron-Gafford, Greg A.

    2017-01-01

    Soil CO2 efflux (Fsoil) represents a significant source of ecosystem CO2 emissions that is rarely quantified with high-temporal-resolution data in carbon flux studies. Fsoil estimates can be obtained by the low-cost gradient method (GM), but the utility of the method is hindered by uncertainties in the application of published models for the diffusion coefficient. Therefore, to address and resolve these uncertainties, we compared Fsoil measured by 2 soil CO2 efflux chambers and Fsoil estimated by 16 gas transport models using the GM across 1 year. We used 14 published empirical gas diffusion models and 2 in situ models: (1) a gas transfer model called "Chamber model" obtained using a calibration between the chamber and the gradient method and (2) a diffusion model called "SF6 model" obtained through an interwell conservative tracer experiment. Most of the published models using the GM underestimated cumulative annual Fsoil by 55% to 361%, while the Chamber model closely approximated cumulative Fsoil (0.6% error). Surprisingly, the SF6 model combined with the GM underestimated Fsoil by 32%. Differences between in situ models could stem from the Chamber model implicitly accounting for production of soil CO2, while the conservative tracer model does not. Therefore, we recommend using the GM only after calibration with chamber measurements to generate reliable long-term ecosystem Fsoil measurements. Accurate estimates of Fsoil will improve our understanding of soil respiration's contribution to ecosystem fluxes.

  4. Improving the accuracy of the diagnosis of schizophrenia by means of virtual reality.

    Science.gov (United States)

    Sorkin, Anna; Weinshall, Daphna; Modai, Ilan; Peled, Avi

    2006-03-01

    The authors' goal was to improve the diagnosis of schizophrenia by using virtual reality technology to build a complex, multimodal environment in which cognitive functions can be studied (and measured) in parallel. The authors studied sensory integration within working memory by means of computer navigation through a virtual maze. The simulated journey consisted of a series of rooms, each of which included three doors. Each door was characterized by three features (color, shape, and sound), and a single combination of features--the door-opening rule--was correct. Subjects had to learn the rule and use it. The participants were 39 schizophrenic patients and 21 healthy comparison subjects. Upon completion, each subject was assigned a performance profile, including various error scores, response time, navigation ability, and strategy. A classification procedure based on the subjects' performance profile correctly predicted 85% of the schizophrenic patients (and all of the comparison subjects). Several performance variables showed significant correlations with scores on a standard diagnostic measure (Positive and Negative Syndrome Scale), suggesting potential use of these measurements for the diagnosis of schizophrenia. On the other hand, the patients did not show unusual repetition of response despite stimulus cessation (called "perseveration" in classical studies of schizophrenia), which is a common symptom of the disease. This deficit appeared only when the subjects did not receive proper explanation of the task. The ability to study multimodal performance simultaneously by using virtual reality technology opens new possibilities for the diagnosis of schizophrenia with objective procedures.

  5. Gravity Probe B data analysis status and potential for improved accuracy of scientific results

    Energy Technology Data Exchange (ETDEWEB)

    Everitt, C W F; Adams, M; Bencze, W; Buchman, S; Clarke, B; Conklin, J; DeBra, D B; Dolphin, M; Heifetz, M; Hipkins, D; Holmes, T; Keiser, G M; Kolodziejczak, J; Li, J; Lockhart, J M; Muhlfelder, B; Parkinson, B W; Salomon, M; Silbergleit, A; Solomonik, V [W W Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305-4085 (United States)] (and others)

    2008-06-07

    Gravity Probe B (GP-B) is a landmark physics experiment in space designed to yield precise tests of two fundamental predictions of Einstein's theory of general relativity, the geodetic and frame-dragging effects, by means of cryogenic gyroscopes in Earth orbit. Launched on 20 April 2004, data collection began on 28 August 2004 and science operations were completed on 29 September 2005 upon liquid helium depletion. During the course of the experiment, two unexpected and mutually-reinforcing complications were discovered: (1) larger than expected 'misalignment' torques on the gyroscopes producing classical drifts larger than the relativity effects under study and (2) a damped polhode oscillation that complicated the calibration of the instrument's scale factor against the aberration of starlight. Steady progress through 2006 and 2007 established the methods for treating both problems; in particular, an extended effort from January 2007 on 'trapped flux mapping' led in August 2007 to a dramatic breakthrough, resulting in a factor of {approx}20 reduction in data scatter. This paper reports results up to November 2007. Detailed investigation of a central 85-day segment of the data has yielded robust measurements of both relativity effects. Expansion to the complete science data set, along with anticipated improvements in modeling and in the treatment of systematic errors may be expected to yield a 3-6% determination of the frame-dragging effect.

  6. Drift Removal for Improving the Accuracy of Gait Parameters Using Wearable Sensor Systems

    Science.gov (United States)

    Takeda, Ryo; Lisco, Giulia; Fujisawa, Tadashi; Gastaldi, Laura; Tohyama, Harukazu; Tadano, Shigeru

    2014-01-01

    Accumulated signal noise will cause the integrated values to drift from the true value when measuring orientation angles of wearable sensors. This work proposes a novel method to reduce the effect of this drift to accurately measure human gait using wearable sensors. Firstly, an infinite impulse response (IIR) digital 4th order Butterworth filter was implemented to remove the noise from the raw gyro sensor data. Secondly, the mode value of the static state gyro sensor data was subtracted from the measured data to remove offset values. Thirdly, a robust double derivative and integration method was introduced to remove any remaining drift error from the data. Lastly, sensor attachment errors were minimized by establishing the gravitational acceleration vector from the acceleration data at standing upright and sitting posture. These improvements proposed allowed for removing the drift effect, and showed an average of 2.1°, 33.3°, 15.6° difference for the hip knee and ankle joint flexion/extension angle, when compared to without implementation. Kinematic and spatio-temporal gait parameters were also calculated from the heel-contact and toe-off timing of the foot. The data provided in this work showed potential of using wearable sensors in clinical evaluation of patients with gait-related diseases. PMID:25490587

  7. Accuracy Improvement by the Least Squares Image Matching Evaluated on the CARTOSAT-1

    Science.gov (United States)

    Afsharnia, H.; Azizi, A.; Arefi, H.

    2015-12-01

    Generating accurate elevation data from satellite images is a prerequisite step for applications that involve disaster forecasting and management using GIS platforms. In this respect, the high resolution satellite optical sensors may be regarded as one of the prime and valuable sources for generating accurate and updated elevation information. However, one of the main drawbacks of conventional approaches for automatic elevation generation from these satellite optical data using image matching techniques is the lack of flexibility in the image matching functional models to take dynamically into account the geometric and radiometric dissimilarities between the homologue stereo image points. The classical least squares image matching (LSM) method, on the other hand, is quite flexible in incorporating the geometric and radiometric variations of image pairs into its functional model. The main objective of this paper is to evaluate and compare the potential of the LSM technique for generating disparity maps from high resolution satellite images to achieve sub pixel precision. To evaluate the rate of success of the LSM, the size of the y-disparities between the homologous points is taken as the precision criteria. The evaluation is performed on the Cartosat-1 stereo along track images over a highly mountainous terrain. The precision improvement is judged based on the standard deviation and the scatter pattern of the y-disparity data. The analysis of the results indicate that, the LSM has achieved the matching precision of about 0.18 pixels which is clearly superior to the manual pointing that yielded the precision of 0.37 pixels.

  8. Improved accuracy of supervised CRM discovery with interpolated Markov models and cross-species comparison.

    Science.gov (United States)

    Kazemian, Majid; Zhu, Qiyun; Halfon, Marc S; Sinha, Saurabh

    2011-12-01

    Despite recent advances in experimental approaches for identifying transcriptional cis-regulatory modules (CRMs, 'enhancers'), direct empirical discovery of CRMs for all genes in all cell types and environmental conditions is likely to remain an elusive goal. Effective methods for computational CRM discovery are thus a critically needed complement to empirical approaches. However, existing computational methods that search for clusters of putative binding sites are ineffective if the relevant TFs and/or their binding specificities are unknown. Here, we provide a significantly improved method for 'motif-blind' CRM discovery that does not depend on knowledge or accurate prediction of TF-binding motifs and is effective when limited knowledge of functional CRMs is available to 'supervise' the search. We propose a new statistical method, based on 'Interpolated Markov Models', for motif-blind, genome-wide CRM discovery. It captures the statistical profile of variable length words in known CRMs of a regulatory network and finds candidate CRMs that match this profile. The method also uses orthologs of the known CRMs from closely related genomes. We perform in silico evaluation of predicted CRMs by assessing whether their neighboring genes are enriched for the expected expression patterns. This assessment uses a novel statistical test that extends the widely used Hypergeometric test of gene set enrichment to account for variability in intergenic lengths. We find that the new CRM prediction method is superior to existing methods. Finally, we experimentally validate 12 new CRM predictions by examining their regulatory activity in vivo in Drosophila; 10 of the tested CRMs were found to be functional, while 6 of the top 7 predictions showed the expected activity patterns. We make our program available as downloadable source code, and as a plugin for a genome browser installed on our servers. © The Author(s) 2011. Published by Oxford University Press.

  9. Analyses to Verify and Improve the Accuracy of the Manufactured Home Energy Audit (MHEA)

    Energy Technology Data Exchange (ETDEWEB)

    Ternes, Mark P [ORNL; Gettings, Michael B [ORNL

    2008-12-01

    A series of analyses were performed to determine the reasons that the Manufactured Home Energy Audit (MHEA) over predicted space-heating energy savings as measured in a recent field test and to develop appropriate corrections to improve its performance. The study used the Home Energy Rating System (HERS) Building Energy Simulation Test (BESTEST) to verify that MHEA accurately calculates the UA-values of mobile home envelope components and space-heating energy loads as compared with other, well-accepted hourly energy simulation programs. The study also used the Procedures for Verification of RESNET Accredited HERS Software Tools to determine that MHEA accurately calculates space-heating energy consumptions for gas furnaces, heat pumps, and electric-resistance furnaces. Even though MHEA's calculations were shown to be correct from an engineering point of view, three modifications to MHEA's algorithms and use of a 0.6 correction factor were incorporated into MHEA to true-up its predicted savings to values measured in a recent field test. A simulated use of the revised version of MHEA in a weatherization program revealed that MHEA would likely still recommend a significant number of cost-effective weatherization measures in mobile homes (including ceiling, floor, and even wall insulation and far fewer storm windows). Based on the findings from this study, it was recommended that a revised version of MHEA with all the changes and modifications outlined in this report should be finalized and made available to the weatherization community as soon as possible, preferably in time for use within the 2009 Program Year.

  10. Improving salt marsh digital elevation model accuracy with full-waveform lidar and nonparametric predictive modeling

    Science.gov (United States)

    Rogers, Jeffrey N.; Parrish, Christopher E.; Ward, Larry G.; Burdick, David M.

    2018-03-01

    Salt marsh vegetation tends to increase vertical uncertainty in light detection and ranging (lidar) derived elevation data, often causing the data to become ineffective for analysis of topographic features governing tidal inundation or vegetation zonation. Previous attempts at improving lidar data collected in salt marsh environments range from simply computing and subtracting the global elevation bias to more complex methods such as computing vegetation-specific, constant correction factors. The vegetation specific corrections can be used along with an existing habitat map to apply separate corrections to different areas within a study site. It is hypothesized here that correcting salt marsh lidar data by applying location-specific, point-by-point corrections, which are computed from lidar waveform-derived features, tidal-datum based elevation, distance from shoreline and other lidar digital elevation model based variables, using nonparametric regression will produce better results. The methods were developed and tested using full-waveform lidar and ground truth for three marshes in Cape Cod, Massachusetts, U.S.A. Five different model algorithms for nonparametric regression were evaluated, with TreeNet's stochastic gradient boosting algorithm consistently producing better regression and classification results. Additionally, models were constructed to predict the vegetative zone (high marsh and low marsh). The predictive modeling methods used in this study estimated ground elevation with a mean bias of 0.00 m and a standard deviation of 0.07 m (0.07 m root mean square error). These methods appear very promising for correction of salt marsh lidar data and, importantly, do not require an existing habitat map, biomass measurements, or image based remote sensing data such as multi/hyperspectral imagery.

  11. Accuracy of intermediate dose of furosemide injection to improve multidetector row CT urography

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Catherine [Department of Radiology B, Universitary Hospital of Strasbourg-Civil Hospital, 1, Place de l' hopital BP 426, 67091 Strasbourg Cedex (France)], E-mail: catherine.roy@chru-strasbourg.fr; Jeantroux, Jeremy; Irani, Farah G.; Sauer, Benoit [Department of Radiology B, Universitary Hospital of Strasbourg-Civil Hospital, 1, Place de l' hopital BP 426, 67091 Strasbourg Cedex (France); Lang, Herve; Saussine, Christian [Department of Urology, Universitary Hospital of Strasbourg-Civil Hospital, 1, Place de l' hopital BP 426, 67091 Strasbourg Cedex (France)

    2008-05-15

    Objective: Evaluate the usefulness of intermediate dose furosemide to improve visualization of the intrarenal collecting system and ureter using MDCTU. Materials and methods: Two groups of 100 patients without urinary tract disease or major abdominal pathology underwent MDCTU. Group I (various abdominal indications) was performed without any additional preparation and Group II (suspicion of urinary tract disease) 10 min after injection of furosemide (20 mg). MIP images of the excretory phase were post-processed. Maximal short-axis diameter of the pelvis and ureter were measured on axial images for all phases. Visualization of the collecting system wall and the identification of the whole ureter were assessed. Results: Mean pelvic diameter before contrast was (7.4 mm, S.D. {+-} 2.7; 13.4 mm, S.D. {+-} 4.1), on cortico-medullary phase (8.4 mm, S.D. {+-} 4.2; 14.3 mm, S.D. {+-} 4), on nephrographic phase (8.1 mm, S.D. {+-} 2.5; 14.8 mm, S.D. {+-} 4) and on excretory phase (9.7 mm, S.D. {+-} 3.4; 14.9 mm, S.D. {+-} 4.5), respectively, for Groups I and II. Intrarenal collecting system wall was clearly identified on both corticomedullary and nephrographic phases in 91% of Group II against 20% of Group I. Opacification of the entire ureter was excellent on excretory phase in 96% of Group II against 13% of Group I. The difference between the mean values for the two groups was statistically significant for all phases (p < 10{sup -9}). Conclusion: Intermediate-dose furosemide (20 mg) before MDCTU is a very simple add-on for accurate depiction of pelvicalyceal details and collecting system wall without artefacts. The procedure is associated with a constant and complete visualisation of the entire urete.

  12. Effective experimental validation of miRNA targets using an improved linker reporter assay.

    Science.gov (United States)

    Choi, Cheolwon; Han, James; Thao Tran, Nguyen Thi; Yoon, Seulgi; Kim, Goeun; Song, Sujung; Kim, Youngjo; Ryu, Seongho

    2017-01-30

    miRNAs are small, non-coding RNAs that play critical roles in various cellular processes. Although there are several algorithms that can predict the potential candidate genes that are regulated by a miRNA, these algorithms require further experimental validation in order to demonstrate genuine targets of miRNAs. Moreover, most algorithms predict hundreds to thousands of putative target genes for each miRNA, and it is difficult to validate all candidates using the whole 3'-untranslated region (UTR) reporter assay. We report a fast, simple and efficient experimental approach to screening miRNA candidate targets using a 3'-UTR linker assay. Critically, the linker has only a short miRNA regulatory element sequence of approximately 22 base pairs in length and can provide a benefit for screening strong miRNA candidates for further validation using the whole 3'-UTR sequence. Our technique will provide a simplified platform for the high-throughput screening of miRNA target gene validation.

  13. Interferon-gamma release assay improves the diagnosis of tuberculosis in children.

    Science.gov (United States)

    Bianchi, Leila; Galli, Luisa; Moriondo, Maria; Veneruso, Giuseppina; Becciolini, Laura; Azzari, Chiara; Chiappini, Elena; de Martino, Maurizio

    2009-06-01

    Interferon-gamma release assays (IGRAs) have been recently developed for the diagnosis of tuberculosis (TB) infection. The aim of the present study was to evaluate the performance of an enzyme-linked immunosorbent assay (ELISA)-based IGRA for detecting TB in children. A prospective study in 336 children at risk for TB infection was carried out. All children were tested with tuberculin skin test (TST) and a commercial ELISA-based IGRA [QuantiFERON-TB Gold In-Tube (Cellestis)]. TST were positive in 58 of 336 (17.3%) and IGRA in 60 of 336 (17.9%) children. Two (0.6%) IGRA results were indeterminate. The overall agreement between the 2 tests was intermediate (86.2%, kappa= 0.533). IGRA was positive in 15 of 16 (93.8%) children with active pulmonary TB. The discordant pattern IGRA-/TST+ was significantly associated with Bacille Calmette-Guérin (BCG) vaccination. Among IGRA+ children (excluding cases of TB disease), TST- were significantly younger than TST+ children. The good agreement between positive IGRA and active TB disease suggests a good sensitivity of IGRA. Discrepancies between IGRA and TST can be a result of higher specificity of IGRA that is not influenced by previous BCG vaccination. IGRA may be more sensitive in children younger than 48 months.

  14. Multiplex ligation-dependent probe amplification assay identifies additional copy number changes compared with R-band karyotype and provide more accuracy prognostic information in myelodysplastic syndromes.

    Science.gov (United States)

    Wang, Jingya; Ai, Xiaofei; Qin, Tiejun; Xu, Zefeng; Zhang, Yue; Liu, Jinqin; Li, Bing; Fang, Liwei; Zhang, Hongli; Pan, Lijuan; Hu, Naibo; Qu, Shiqiang; Cai, Wenyu; Ru, Kun; Jia, Yujiao; Huang, Gang; Xiao, Zhijian

    2017-01-03

    Cytogenetic analysis provides important diagnostic and prognostic information for patients with Myelodysplastic syndromes (MDS) and plays an essential role in the International Prognostic Scoring System (IPSS) and the revised International Prognostic Scoring System (IPSS-R). Multiplex ligation-dependent probe amplification (MLPA) assay is a recently developed technique to identify targeted cytogenetic aberrations in MDS patients. In the present study, we evaluated the results obtained using an MLPA assay in 437 patients with MDS to determine the efficacy of MLPA analysis. Using R-banding karyotyping, 45% (197/437) of MDS patients had chromosomal abnormalities, whereas MLPA analysis detected that 35% (153/437) of MDS cases contained at least one copy-number variations (CNVs) .2/5 individuals (40%) with R-band karyotype failures had trisomy 8 detected using only MLPA. Clonal cytogenetic abnormalities were detected in 20/235 (8.5%) MDS patients with a normal R-band karyotype, and 12/20 (60%) of those patients were reclassified into a higher-risk IPSS-R prognostic category. When sequencing and cytogenetics were combined, the fraction of patients with MDS-related oncogenic lesions increased to 87.3% (233/267 cases). MLPA analysis determined that the median OS of patients with a normal karyotype (n=218) was 65 months compared with 27 months in cases with an aberrant karyotype (P=0.002) in 240 patients with normal or failed karyotypes by R-banding karyotyping. The high-resolution MPLA assay is an efficient and reliable method that can be used in conjunction with R-band karyotyping to detect chromosomal abnormalities in patients with suspected MDS. MLPA may also provide more accurate prognostic information.

  15. Multiplex ligation-dependent probe amplification assay identifies additional copy number changes compared with R-band karyotype and provide more accuracy prognostic information in myelodysplastic syndromes

    Science.gov (United States)

    Xu, Zefeng; Zhang, Yue; Liu, Jinqin; Li, Bing; Fang, Liwei; Zhang, Hongli; Pan, Lijuan; Hu, Naibo; Qu, Shiqiang; Cai, Wenyu; Ru, Kun; Jia, Yujiao; Huang, Gang; Xiao, Zhijian

    2017-01-01

    Cytogenetic analysis provides important diagnostic and prognostic information for patients with Myelodysplastic syndromes (MDS) and plays an essential role in the International Prognostic Scoring System (IPSS) and the revised International Prognostic Scoring System (IPSS-R). Multiplex ligation-dependent probe amplification (MLPA) assay is a recently developed technique to identify targeted cytogenetic aberrations in MDS patients. In the present study, we evaluated the results obtained using an MLPA assay in 437 patients with MDS to determine the efficacy of MLPA analysis. Using R-banding karyotyping, 45% (197/437) of MDS patients had chromosomal abnormalities, whereas MLPA analysis detected that 35% (153/437) of MDS cases contained at least one copy-number variations (CNVs) .2/5 individuals (40%) with R-band karyotype failures had trisomy 8 detected using only MLPA. Clonal cytogenetic abnormalities were detected in 20/235 (8.5%) MDS patients with a normal R-band karyotype, and 12/20 (60%) of those patients were reclassified into a higher-risk IPSS-R prognostic category. When sequencing and cytogenetics were combined, the fraction of patients with MDS-related oncogenic lesions increased to 87.3% (233/267 cases). MLPA analysis determined that the median OS of patients with a normal karyotype (n=218) was 65 months compared with 27 months in cases with an aberrant karyotype (P=0.002) in 240 patients with normal or failed karyotypes by R-banding karyotyping. The high-resolution MPLA assay is an efficient and reliable method that can be used in conjunction with R-band karyotyping to detect chromosomal abnormalities in patients with suspected MDS. MLPA may also provide more accurate prognostic information. PMID:27906673

  16. Cardiopulmonary ultrasound for critically ill adults improves diagnostic accuracy in a resource-limited setting: the AFRICA trial.

    Science.gov (United States)

    Becker, Torben K; Tafoya, Chelsea A; Osei-Ampofo, Maxwell; Tafoya, Matthew J; Kessler, Ross A; Theyyunni, Nikhil; Yakubu, Hussein A; Opuni, Daniel; Clauw, Daniel J; Cranford, James A; Oppong, Chris K; Oteng, Rockefeller A

    2017-12-01

    To assess the effects of a cardiopulmonary ultrasound (CPUS) examination on diagnostic accuracy for critically ill patients in a resource-limited setting. Approximately half of the emergency medicine resident physicians at the Komfo Anokye Teaching Hospital (KATH) in Kumasi, Ghana, were trained in a CPUS protocol. Adult patients triaged to the resuscitation area of the emergency department (ED) were enrolled if they exhibited signs or symptoms of shock or respiratory distress. Patients were assigned to the intervention group if their treating physician had completed the CPUS training. The physician's initial diagnostic impression was recorded immediately after the history and physical examination in the control group, and after an added CPUS examination in the intervention group. This was compared to a standardised final diagnosis derived from post hoc chart review of the patient's care at 24 h by two blinded, independent reviewers using a clearly defined and systematic process. Secondary outcomes were 24-h mortality and use of IV fluids, diuretics, vasopressors and bronchodilators. Of 890 patients presenting during the study period, 502 were assessed for eligibility, and 180 patients were enrolled. Diagnostic accuracy was higher for patients who received the CPUS examination (71.9% vs. 57.1%, Δ 14.8% [CI 0.5%, 28.4%]). This effect was particularly pronounced for patients with a 'cardiac' diagnosis, such as cardiogenic shock, congestive heart failure or acute valvular disease (94.7% vs. 40.0%, Δ 54.7% [CI 8.9%, 86.4%]). Secondary outcomes were not different between groups. In an urban ED in Ghana, a CPUS examination improved the accuracy of the treating physician's initial diagnostic impression. There were no differences in 24-h mortality and a number of patient care interventions. © 2017 John Wiley & Sons Ltd.

  17. Development and Characterization of an HPV Type-16 Specific Modified DNA Aptamer for the Improvement of Potency Assays.

    Science.gov (United States)

    Trausch, Jeremiah J; Shank-Retzlaff, Mary; Verch, Thorsten

    2017-03-21

    Measuring vaccine potency is critical for vaccine release and is often accomplished using antibody-based ELISAs. Antibodies can be associated with significant drawbacks that are often overlooked including lot-to-lot variability, problems with cell-line maintenance, limited stability, high cost, and long discovery lead times. Here, we address many of these issues through the development of an aptamer, known as a slow off-rate modified DNA aptamer (SOMAmer), which targets a vaccine antigen in the human papillomavirus (HPV) vaccine Gardasil. The aptamer, termed HPV-07, was selected to bind the Type 16 virus-like-particle (VLP) formed by the self-assembling capsid protein L1. It is capable of binding with high sensitivity (EC50 of 0.1 to 0.4 μg/mL depending on assay format) while strongly discriminating against other VLP types. The aptamer competes for binding with the neutralizing antibody H16.V5, indicating at least partial recognition of a neutralizing and clinically relevant epitope. This makes it a useful reagent for measuring both potency and stability. When used in an ELISA format, the aptamer displays both high precision (intermediate precision of 6.3%) and a large linear range spanning from 25% to 200% of a typical formulation. To further exploit the advantages of aptamers, a simplified mix and read assay was also developed. This assay format offers significant time and resource reductions compared to a traditional ELISA. These results show aptamers are suitable reagents for biological potency assays, and we expect that their implementation could improve upon current assay formats.

  18. Reducing the influence of spatial resolution to improve quantitative accuracy in emission tomography: A comparison of potential strategies

    Science.gov (United States)

    Hutton, B. F.; Olsson, A.; Som, S.; Erlandsson, K.; Braun, M.

    2006-12-01

    The goal of this paper is to compare strategies for reducing partial volume effects by either minimizing the cause (i.e. improving resolution) or correcting the effect. Correction for resolution loss can be achieved either by modelling the resolution for use in iterative reconstruction or by imposing constraints based on knowledge of the underlying anatomy. Approaches to partial volume correction largely rely on knowledge of the underlying anatomy, based on well-registered high-resolution anatomical imaging modalities (CT or MRI). Corrections can be applied by considering the signal loss that results by smoothing the high-resolution modality to the same resolution as obtained in emission tomography. A physical phantom representing the central brain structures was used to evaluate the quantitative accuracy of the various strategies for either improving resolution or correcting for partial volume effects. Inclusion of resolution in the reconstruction model improved the measured contrast for the central brain structures but still underestimated the true object contrast (˜0.70). Use of information on the boundaries of the structures in conjunction with a smoothing prior using maximum entropy reconstruction achieved some degree of contrast enhancement and improved the noise properties of the resulting images. Partial volume correction based on segmentation of registered anatomical images and knowledge of the reconstructed resolution permitted more accurate quantification of the target to background ratio for individual brain structures.

  19. Improvement of Accuracy of Proper Motions of Hipparcos Catalogue Stars Using Optical Latitude Observations

    Science.gov (United States)

    Damljanovic, G.

    2009-09-01

    ), Mizusawa (MZL FZT), Tuorla -- Turku (TT VZT), Mizusawa (MZP and MZQ PZT), Mount Stromlo (MS PZT), Ondřejov (OJP PZT), Punta Indio (PIP PZT), Richmond (RCP and RCQ PZT) and Washington (WA, W and WGQ PZT). The task is to improve the proper motions in declination of the observed Hipparcos stars. The original method was developed, and it consists of removing from the instantaneous observed latitudes all known effects (polar motion and some local instrumental errors). The corrected latitudes are then used to calculate the corrections of the Hipparcos proper motions in declination (Damljanović 2005). The Least Squares Method (LSM) is used with the linear model. We compared the calculated results with ARIHIP and EOC-2 data, and found a good agreement. The newly obtained values of proper motions in declination are substantially more precise than those of the Hipparcos Catalogue. It is because the time interval covered by the latitude observations (tens of years) is much longer than the Hipparcos one (less than four years), and because of the great number of observations made during this interval (Damljanović et al. 2006). Our method is completely different from the one used to compute the EOC-2 catalogue (Vondrák 2004). It was also an almost independent check of the proper motions of EOC-2. The catalogue EOC-2 is used in this thesis to distinguish the corrections of the two stars of a pair observed by using the Horrebow -- Talcott method. The difference between the two proper motions is constrained by the difference in the EOC-2 and Hipparcos catalogues (Damljanović and Pejović 2006). The main result of the thesis is the catalogue of proper motions in declination of 2347 Hipparcos stars.

  20. Improving accuracy in shallow-landslide susceptibility analyses at regional scale

    Science.gov (United States)

    Iovine, Giulio G. R.; Rago, Valeria; Frustaci, Francesco; Bruno, Claudia; Giordano, Stefania; Muto, Francesco; Gariano, Stefano L.; Pellegrino, Annamaria D.; Conforti, Massimo; Pascale, Stefania; Distilo, Daniela; Basile, Vincenzo; Soleri, Sergio; Terranova, Oreste G.

    2015-04-01

    Calabria (southern Italy) is particularly exposed to geo-hydrological risk. In the last decades, slope instabilities, mainly related to rainfall-induced landslides, repeatedly affected its territory. Among these, shallow landslides, characterized by abrupt onset and extremely rapid movements, are among the most destructive and dangerous phenomena for people and infrastructures. In this study, a susceptibility analysis to shallow landslides has been performed by refining a method recently applied in Costa Viola - central Calabria (Iovine et al., 2014), and only focusing on landslide source activations (regardless of their possible evolution as debris flows). A multivariate approach has been applied to estimating the presence/absence of sources, based on linear statistical relationships with a set of causal variables. The different classes of numeric causal variables have been determined by means of a data clustering method, designed to determine the best arrangement. A multi-temporal inventory map of sources, mainly obtained from interpretation of air photographs taken in 1954-1955, and in 2000, has been adopted to selecting the training and the validation sets. Due to the wide extend of the territory, the analysis has been iteratively performed by a step-by-step decreasing cell-size approach, by adopting greater spatial resolutions and thematic details (e.g. lithology, land-use, soil, morphometry, rainfall) for high-susceptible sectors. Through a sensitivity analysis, the weight of the considered factors in predisposing shallow landslides has been evaluated. The best set of variables has been identified by iteratively including one variable at a time, and comparing the results in terms of performance. Furthermore, susceptibility evaluations obtained through logistic regression have been compared to those obtained by applying neural networks. Obtained results may be useful to improve land utilization planning, and to select proper mitigation measures in shallow

  1. Optimal Triage Test Characteristics to Improve the Cost-Effectiveness of the Xpert MTB/RIF Assay for TB Diagnosis: A Decision Analysis

    Science.gov (United States)

    van’t Hoog, Anna H.; Cobelens, Frank; Vassall, Anna; van Kampen, Sanne; Dorman, Susan E.; Alland, David; Ellner, Jerrold

    2013-01-01

    Background High costs are a limitation to scaling up the Xpert MTB/RIF assay (Xpert) for the diagnosis of tuberculosis in resource-constrained settings. A triaging strategy in which a sensitive but not necessarily highly specific rapid test is used to select patients for Xpert may result in a more affordable diagnostic algorithm. To inform the selection and development of particular diagnostics as a triage test we explored combinations of sensitivity, specificity and cost at which a hypothetical triage test will improve affordability of the Xpert assay. Methods In a decision analytical model parameterized for Uganda, India and South Africa, we compared a diagnostic algorithm in which a cohort of patients with presumptive TB received Xpert to a triage algorithm whereby only those with a positive triage test were tested by Xpert. Findings A triage test with sensitivity equal to Xpert, 75% specificity, and costs of US$5 per patient tested reduced total diagnostic costs by 42% in the Uganda setting, and by 34% and 39% respectively in the India and South Africa settings. When exploring triage algorithms with lower sensitivity, the use of an example triage test with 95% sensitivity relative to Xpert, 75% specificity and test costs $5 resulted in similar cost reduction, and was cost-effective by the WHO willingness-to-pay threshold compared to Xpert for all in Uganda, but not in India and South Africa. The gain in affordability of the examined triage algorithms increased with decreasing prevalence of tuberculosis among the cohort. Conclusions A triage test strategy could potentially improve the affordability of Xpert for TB diagnosis, particularly in low-income countries and with enhanced case-finding. Tests and markers with lower accuracy than desired of a diagnostic test may fall within the ranges of sensitivity, specificity and cost required for triage tests and be developed as such. PMID:24367555

  2. Improving Prediction Accuracy of “Central Line-Associated Blood Stream Infections” Using Data Mining Models

    Directory of Open Access Journals (Sweden)

    Amin Y. Noaman

    2017-01-01

    Full Text Available Prediction of nosocomial infections among patients is an important part of clinical surveillance programs to enable the related personnel to take preventive actions in advance. Designing a clinical surveillance program with capability of predicting nosocomial infections is a challenging task due to several reasons, including high dimensionality of medical data, heterogenous data representation, and special knowledge required to extract patterns for prediction. In this paper, we present details of six data mining methods implemented using cross industry standard process for data mining to predict central line-associated blood stream infections. For our study, we selected datasets of healthcare-associated infections from US National Healthcare Safety Network and consumer survey data from Hospital Consumer Assessment of Healthcare Providers and Systems. Our experiments show that central line-associated blood stream infections (CLABSIs can be successfully predicted using AdaBoost method with an accuracy up to 89.7%. This will help in implementing effective clinical surveillance programs for infection control, as well as improving the accuracy detection of CLABSIs. Also, this reduces patients’ hospital stay cost and maintains patients’ safety.

  3. A Modified LS+AR Model to Improve the Accuracy of the Short-term Polar Motion Prediction

    Science.gov (United States)

    Wang, Z. W.; Wang, Q. X.; Ding, Y. Q.; Zhang, J. J.; Liu, S. S.

    2017-03-01

    There are two problems of the LS (Least Squares)+AR (AutoRegressive) model in polar motion forecast: the inner residual value of LS fitting is reasonable, but the residual value of LS extrapolation is poor; and the LS fitting residual sequence is non-linear. It is unsuitable to establish an AR model for the residual sequence to be forecasted, based on the residual sequence before forecast epoch. In this paper, we make solution to those two problems with two steps. First, restrictions are added to the two endpoints of LS fitting data to fix them on the LS fitting curve. Therefore, the fitting values next to the two endpoints are very close to the observation values. Secondly, we select the interpolation residual sequence of an inward LS fitting curve, which has a similar variation trend as the LS extrapolation residual sequence, as the modeling object of AR for the residual forecast. Calculation examples show that this solution can effectively improve the short-term polar motion prediction accuracy by the LS+AR model. In addition, the comparison results of the forecast models of RLS (Robustified Least Squares)+AR, RLS+ARIMA (AutoRegressive Integrated Moving Average), and LS+ANN (Artificial Neural Network) confirm the feasibility and effectiveness of the solution for the polar motion forecast. The results, especially for the polar motion forecast in the 1-10 days, show that the forecast accuracy of the proposed model can reach the world level.

  4. Using a Structural Root System Model to Evaluate and Improve the Accuracy of Root Image Analysis Pipelines.

    Science.gov (United States)

    Lobet, Guillaume; Koevoets, Iko T; Noll, Manuel; Meyer, Patrick E; Tocquin, Pierre; Pagès, Loïc; Périlleux, Claire

    2017-01-01

    Root system analysis is a complex task, often performed with fully automated image analysis pipelines. However, the outcome is rarely verified by ground-truth data, which might lead to underestimated biases. We have used a root model, ArchiSimple, to create a large and diverse library of ground-truth root system images (10,000). For each image, three levels of noise were created. This library was used to evaluate the accuracy and usefulness of several image descriptors classically used in root image analysis softwares. Our analysis highlighted that the accuracy of the different traits is strongly dependent on the quality of the images and the type, size, and complexity of the root systems analyzed. Our study also demonstrated that machine learning algorithms can be trained on a synthetic library to improve the estimation of several root system traits. Overall, our analysis is a call to caution when using automatic root image analysis tools. If a thorough calibration is not performed on the dataset of interest, unexpected errors might arise, especially for large and complex root images. To facilitate such calibration, both the image library and the different codes used in the study have been made available to the community.

  5. The Impact of Implicit Tasks on Improving the Learners’ Writing in Terms of Autonomy and Grammatical Accuracy

    Directory of Open Access Journals (Sweden)

    Nastaran Nazari

    2014-01-01

    Full Text Available This paper aims to explore the Iranian EFL (English as a Foreign Language learners' ability to gain grammatical accuracy in their writing by noticing and correcting their own grammatical errors. Recent literature in language acquisition has emphasized the role of implicit tasks in encouraging learners to develop autonomous language learning habits, so it is important to consider tasks, particularly implicit tasks, as an important part of language teaching. In this study 60 EFL students from two elementary English classes were chosen. The students of one class were engaged in an implicit task in which they compared the use of grammar in their own writing to the use of that grammar in a written text by a native speaker, and the other class received no such treatment. The results indicated that the subjects who had received the treatment performed much better on the post-test. The outcome of the delayed post-test also confirmed the superior performance of the learners in the experimental group showing that they had internalized the targeted structure. Thus such tasks are beneficial in terms of allowing learners to autonomously make improvements in terms of grammatical accuracy in their writings.

  6. An improved AhR reporter gene assay for analyzing dioxins in soil, sediment and fish.

    Science.gov (United States)

    Chao, How-Ran; Wang, Ya-Fan; Wang, Yao-Nan; Lin, Ding-Yan; Gou, Yan-You; Chen, Chien-Yu; Chen, Kuan-Chung; Wu, Wen-Kai; Chiang, Bao-An; Huang, Yu-Ting; Hsieh, Lien-Te; Yeh, Kuei-Jyum C; Tsou, Tsui-Chun

    2012-10-01

    Our goal was to develop a fast-screening bioassay to determine dioxin levels in the environmental and biological samples from dioxin-contaminated areas. Our original dioxin-responsive-element (DRE)-driven luciferase bioassay (using Huh7-DRE-Luc cells) was modified by reducing the incubation temperature of the cell culture from 37 to 35°C and by adding phorbol-12-myristate-13-acetate, and the modified bioassay was used to examine samples from soil, sediment, and fish. The results of this bioassay were shown to be significantly related to those of the high-resolution gas chromatography/high-resolution mass spectrometry assay of dioxins. The correlative equation was: log (PCDD/Fs I-TEQs) = 1.19 × log (BEQs) - 1.15 with R(2) = 0.95 (p < 0.001).

  7. Using radar ground-truth to validate and improve the location accuracy of a lightning direction-finding network

    Science.gov (United States)

    Goodman, Steven J.

    1989-01-01

    A technique is described in which isolated radar echoes associated with clusters of lightning strikes are used to validate and improve the location accuracy of a lightning-direction-finding network. Using this technique, site errors of a magnetic direction-finding network for locating lightning strikes to ground were accurately determined. The technique offers advantages over existing techniques in that large sample sizes are readily attainable over a broad area on a regular basis; the technique can also provide additional constraints to redundant data methods such as that described by Orville (1987). Since most lightning strike networks have either partial or full weather radar coverage, the technique is practical for all but a few users.

  8. Iterative Image Reconstruction Improves the Accuracy of Automated Plaque Burden Assessment in Coronary CT Angiography: A Comparison With Intravascular Ultrasound.

    Science.gov (United States)

    Puchner, Stefan B; Ferencik, Maros; Maehara, Akiko; Stolzmann, Paul; Ma, Shixin; Do, Synho; Kauczor, Hans-Ulrich; Mintz, Gary S; Hoffmann, Udo; Schlett, Christopher L

    2017-04-01

    The purpose of this study was to determine whether use of iterative image reconstruction algorithms improves the accuracy of coronary CT angiography (CCTA) compared with intravascular ultrasound (IVUS) in semiautomated plaque burden assessment. CCTA and IVUS images of seven coronary arteries were acquired ex vivo. CT images were reconstructed with filtered back projection (FBP) and adaptive statistical (ASIR) and model-based (MBIR) iterative reconstruction algorithms. Cross-sectional images of the arteries were coregistered between CCTA and IVUS in 1-mm increments. In CCTA, fully automated (without manual corrections) and semiautomated (allowing manual corrections of vessel wall boundaries) plaque burden assessments were performed for each of the reconstruction algorithms with commercially available software. In IVUS, plaque burden was measured manually. Agreement between CCTA and IVUS was determined with Pearson correlation. A total of 173 corresponding cross sections were included. The mean plaque burden measured with IVUS was 63.39% ± 10.63%. With CCTA and the fully automated technique, it was 54.90% ± 11.70% with FBP, 53.34% ± 13.11% with ASIR, and 55.35% ± 12.22% with MBIR. With CCTA and the semiautomated technique mean plaque burden was 54.90% ± 11.76%, 53.40% ± 12.85%, 57.09% ± 11.05%. Manual correction of the semiautomated assessments was performed in 39% of all cross sections and improved plaque burden correlation with the IVUS assessment independently of reconstruction algorithm (p reconstruction algorithms such as FBP, independently of the use of a fully automated or semiautomated assessment approach. The highest accuracy for quantifying plaque burden with CCTA can be achieved by using MBIR data with semiautomated assessment.

  9. Reassessment of CT images to improve diagnostic accuracy in patients with suspected acute appendicitis and an equivocal preoperative CT interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Cheol; Yang, Dal Mo; Kim, Sang Won [Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Department of Radiology, Seoul (Korea, Republic of); Park, Seong Jin [Kyung Hee University Hospital, College of Medicine, Kyung Hee University, Department of Radiology, Seoul (Korea, Republic of)

    2012-06-15

    To identify CT features that discriminate individuals with and without acute appendicitis in patients with equivocal CT findings, and to assess whether knowledge of these findings improves diagnostic accuracy. 53 patients that underwent appendectomy with an indeterminate preoperative CT interpretation were selected and allocated to an acute appendicitis group or a non-appendicitis group. The 53 CT examinations were reviewed by two radiologists in consensus to identify CT findings that could aid in the discrimination of those with and without appendicitis. In addition, two additional radiologists were then requested to evaluate independently the 53 CT examinations using a 4-point scale, both before and after being informed of the potentially discriminating criteria. CT findings found to be significantly different in the two groups were; the presence of appendiceal wall enhancement, intraluminal air in appendix, a coexistent inflammatory lesion, and appendiceal wall thickening (P < 0.05). Areas under the curves of reviewers 1 and 2 significantly increased from 0.516 and 0.706 to 0.677 and 0.841, respectively, when reviewers were told which CT variables were significant (P = 0.0193 and P = 0.0397, respectively). Knowledge of the identified CT findings was found to improve diagnostic accuracy for acute appendicitis in patients with equivocal CT findings. circle Numerous patients with clinically equivocal appendicitis do not have acute appendicitis circle Computed tomography (CT) helps to reduce the negative appendectomy rate circle CT is not always infallible and may also demonstrate indeterminate findings circle However knowledge of significant CT variables can further reduce negative appendectomy rate circle An equivocal CT interpretation of appendicitis should be reassessed with this knowledge. (orig.)

  10. Patient-specific guides do not improve accuracy in total knee arthroplasty: a prospective randomized controlled trial.

    Science.gov (United States)

    Victor, Jan; Dujardin, Jan; Vandenneucker, Hilde; Arnout, Nele; Bellemans, Johan

    2014-01-01

    Recently, patient-specific guides (PSGs) have been introduced, claiming a significant improvement in accuracy and reproducibility of component positioning in TKA. Despite intensive marketing by the manufacturers, this claim has not yet been confirmed in a controlled prospective trial. We (1) compared three-planar component alignment and overall coronal mechanical alignment between PSG and conventional instrumentation and (2) logged the need for applying changes in the suggested position of the PSG. In this randomized controlled trial, we enrolled 128 patients. In the PSG cohort, surgical navigation was used as an intraoperative control. When the suggested cut deviated more than 3° from target, the use of PSG was abandoned and marked as an outlier. When cranial-caudal position or size was adapted, the PSG was marked as modified. All patients underwent long-leg standing radiography and CT scan. Deviation of more than 3° from the target in any plane was defined as an outlier. The PSG and conventional cohorts showed similar numbers of outliers in overall coronal alignment (25% versus 28%; p = 0.69), femoral coronal alignment (7% versus 14%) (p = 0.24), and femoral axial alignment (23% versus 17%; p = 0.50). There were more outliers in tibial coronal (15% versus 3%; p = 0.03) and sagittal 21% versus 3%; p = 0.002) alignment in the PSG group than in the conventional group. PSGs were abandoned in 14 patients (22%) and modified in 18 (28%). PSGs do not improve accuracy in TKA and, in our experience, were somewhat impractical in that the procedure needed to be either modified or abandoned with some frequency.

  11. Improved quantification accuracy for duplex real-time PCR detection of genetically modified soybean and maize in heat processed foods

    Directory of Open Access Journals (Sweden)

    CHENG Fang

    2013-04-01

    Full Text Available Real-time PCR technique has been widely used in quantitative GMO detection in recent years.The accuracy of GMOs quantification based on the real-time PCR methods is still a difficult problem,especially for the quantification of high processed samples.To develop the suitable and accurate real-time PCR system for high processed GM samples,we made ameliorations to several real-time PCR parameters,including re-designed shorter target DNA fragment,similar lengths of amplified endogenous and exogenous gene targets,similar GC contents and melting temperatures of PCR primers and TaqMan probes.Also,one Heat-Treatment Processing Model (HTPM was established using soybean flour samples containing GM soybean GTS 40-3-2 to validate the effectiveness of the improved real-time PCR system.Tested results showed that the quantitative bias of GM content in heat processed samples were lowered using the new PCR system.The improved duplex real-time PCR was further validated using processed foods derived from GM soybean,and more accurate GM content values in these foods was also achieved.These results demonstrated that the improved duplex real-time PCR would be quite suitable in quantitative detection of high processed food products.

  12. Improved accuracy of myocardial perfusion SPECT for detection of coronary artery disease by machine learning in a large population.

    Science.gov (United States)

    Arsanjani, Reza; Xu, Yuan; Dey, Damini; Vahistha, Vishal; Shalev, Aryeh; Nakanishi, Rine; Hayes, Sean; Fish, Mathews; Berman, Daniel; Germano, Guido; Slomka, Piotr J

    2013-08-01

    We aimed to improve the diagnostic accuracy of myocardial perfusion SPECT (MPS) by integrating clinical data and quantitative image features with machine learning (ML) algorithms. 1,181 rest (201)Tl/stress (99m)Tc-sestamibi dual-isotope MPS studies [713 consecutive cases with correlating invasive coronary angiography (ICA) and suspected coronary artery disease (CAD) and 468 with low likelihood (LLk) of CAD rest perfusion change, and transient ischemic dilatation were derived by automated perfusion quantification software and were combined with age, sex, and post-electrocardiogram CAD probability by a boosted ensemble ML algorithm (LogitBoost). The diagnostic accuracy of the model for prediction of obstructive CAD ≥70% was compared to standard prone/supine quantification and to visual analysis by two experienced readers utilizing all imaging, quantitative, and clinical data. Tenfold stratified cross-validation was performed. The diagnostic accuracy of ML (87.3% ± 2.1%) was similar to Expert 1 (86.0% ± 2.1%), but superior to combined supine/prone TPD (82.8% ± 2.2%) and Expert 2 (82.1% ± 2.2%) (P < .01). The receiver operator characteristic areas under curve for ML algorithm (0.94 ± 0.01) were higher than those for TPD and both visual readers (P < .001). The sensitivity of ML algorithm (78.9% ± 4.2%) was similar to TPD (75.6% ± 4.4%) and Expert 1 (76.3% ± 4.3%), but higher than that of Expert 2 (71.1% ± 4.6%), (P < .01). The specificity of ML algorithm (92.1% ± 2.2%) was similar to Expert 1 (91.4% ± 2.2%) and Expert 2 (88.3% ± 2.5%), but higher than TPD (86.8% ± 2.6%), (P < .01). ML significantly improves diagnostic performance of MPS by computational integration of quantitative perfusion and clinical data to the level rivaling expert analysis.

  13. Improved accuracy of quantitative parameter estimates in dynamic contrast-enhanced CT study with low temporal resolution

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sun Mo, E-mail: Sunmo.Kim@rmp.uhn.on.ca [Radiation Medicine Program, Princess Margaret Hospital/University Health Network, Toronto, Ontario M5G 2M9 (Canada); Haider, Masoom A. [Department of Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Medical Imaging, University of Toronto, Toronto, Ontario M5G 2M9 (Canada); Jaffray, David A. [Radiation Medicine Program, Princess Margaret Hospital/University Health Network, Toronto, Ontario M5G 2M9, Canada and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5G 2M9 (Canada); Yeung, Ivan W. T. [Radiation Medicine Program, Princess Margaret Hospital/University Health Network, Toronto, Ontario M5G 2M9 (Canada); Department of Medical Physics, Stronach Regional Cancer Centre, Southlake Regional Health Centre, Newmarket, Ontario L3Y 2P9 (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5G 2M9 (Canada)

    2016-01-15

    Purpose: A previously proposed method to reduce radiation dose to patient in dynamic contrast-enhanced (DCE) CT is enhanced by principal component analysis (PCA) filtering which improves the signal-to-noise ratio (SNR) of time-concentration curves in the DCE-CT study. The efficacy of the combined method to maintain the accuracy of kinetic parameter estimates at low temporal resolution is investigated with pixel-by-pixel kinetic analysis of DCE-CT data. Methods: The method is based on DCE-CT scanning performed with low temporal resolution to reduce the radiation dose to the patient. The arterial input function (AIF) with high temporal resolution can be generated with a coarsely sampled AIF through a previously published method of AIF estimation. To increase the SNR of time-concentration curves (tissue curves), first, a region-of-interest is segmented into squares composed of 3 × 3 pixels in size. Subsequently, the PCA filtering combined with a fraction of residual information criterion is applied to all the segmented squares for further improvement of their SNRs. The proposed method was applied to each DCE-CT data set of a cohort of 14 patients at varying levels of down-sampling. The kinetic analyses using the modified Tofts’ model and singular value decomposition method, then, were carried out for each of the down-sampling schemes between the intervals from 2 to 15 s. The results were compared with analyses done with the measured data in high temporal resolution (i.e., original scanning frequency) as the reference. Results: The patients’ AIFs were estimated to high accuracy based on the 11 orthonormal bases of arterial impulse responses established in the previous paper. In addition, noise in the images was effectively reduced by using five principal components of the tissue curves for filtering. Kinetic analyses using the proposed method showed superior results compared to those with down-sampling alone; they were able to maintain the accuracy in the

  14. HPLC purification of recombinant NcGRA6 antigen improves enzyme-linked immunosorbent assay for serodiagnosis of bovine neosporosis.

    Science.gov (United States)

    Jenkins, M C; Fetterer, R; Schares, G; Björkman, C; Wapenaar, W; McAllister, M; Dubey, J P

    2005-08-10

    The gene for a dense granule protein (NcGRA6) of Neospora caninum was expressed in Escherichia coli as a His-tag fusion protein and purified by NiNTA affinity chromatography. In a preliminary study, high binding of antibodies from N. caninum-negative cows was observed in enzyme-linked immunosorbent assay (ELISA) using NiNTA-purified NcGRA6. Analysis of NiNTA eluates revealed a significant number of E. coli proteins that co-purified with recombinant NcGRA6. In an attempt to improve the relative sensitivity and specificity of the NcGRA6-based ELISA, the rNcGRA6 eluates were subjected to a secondary purification using reverse phase-high performance liquid chromatography (RP-HPLC). Analysis of RP-HPLC eluates by SDS-PAGE/silver staining revealed the purification of recombinant NcGRA6 from contaminating E. coli proteins. ELISAs using the RP-HPLC purified NcGRA6 (dELISA) or singly purified NcGRA6 (sELISA) for identifying seropositive and seronegative cows in a beef herd experiencing an epidemic outbreak of neosporosis were compared to standard assays based on native tachyzoite protein-immunofluorescence antibody test, immunoblot assay, and ISCOM-ELISA. The relative sensitivity, specificity, and kappa value of the NcGRA6d-ELISA were greatly improved over the NcGRA6s-ELISA when compared to the three native antigen immunoassays. These results indicate that removal of contaminating E. coli proteins improves the performance of recombinant NcGRA6 ELISA in diagnosing bovine neosporosis, and may have applicability to the use of recombinant proteins in diagnosing other infectious agents.

  15. Plasmodium serine hydroxymethyltransferase as a potential anti-malarial target: inhibition studies using improved methods for enzyme production and assay

    Directory of Open Access Journals (Sweden)

    Sopitthummakhun Kittipat

    2012-06-01

    Full Text Available Abstract Background There is an urgent need for the discovery of new anti-malarial drugs. Thus, it is essential to explore different potential new targets that are unique to the parasite or that are required for its viability in order to develop new interventions for treating the disease. Plasmodium serine hydroxymethyltransferase (SHMT, an enzyme in the dTMP synthesis cycle, is a potential target for such new drugs, but convenient methods for producing and assaying the enzyme are still lacking, hampering the ability to screen inhibitors. Methods Production of recombinant Plasmodium falciparum SHMT (PfSHMT and Plasmodium vivax SHMT (PvSHMT, using auto-induction media, were compared to those using the conventional Luria Bertani medium with isopropyl thio-β-D-galactoside (LB-IPTG induction media. Plasmodium SHMT activity, kinetic parameters, and response to inhibitors were measured spectrophotometrically by coupling the reaction to that of 5,10-methylenetetrahydrofolate dehydrogenase (MTHFD. The identity of the intermediate formed upon inactivation of Plasmodium SHMTs by thiosemicarbazide was investigated by spectrophotometry, high performance liquid chromatography (HPLC, and liquid chromatography-mass spectrometry (LC-MS. The active site environment of Plasmodium SHMT was probed based on changes in the fluorescence emission spectrum upon addition of amino acids and folate. Results Auto-induction media resulted in a two to three-fold higher yield of Pf- and PvSHMT (7.38 and 29.29 mg/L compared to that produced in cells induced in LB-IPTG media. A convenient spectrophotometric activity assay coupling Plasmodium SHMT and MTHFD gave similar kinetic parameters to those previously obtained from the anaerobic assay coupling SHMT and 5,10-methylenetetrahydrofolate reductase (MTHFR; thus demonstrating the validity of the new assay procedure. The improved method was adopted to screen for Plasmodium SHMT inhibitors, of which some were originally designed

  16. Improving the estimation of tuberculosis infection prevalence using T-cell-based assay and mixture models

    Science.gov (United States)

    Pai, M.; Dendukuri, N.; Wang, L.; Joshi, R.; Kalantri, S.; Rieder, H. L.

    2010-01-01

    SUMMARY BACKGROUND The prevalence of latent tuberculosis infection (LTBI) is traditionally estimated using the tuberculin skin test (TST). Highly specific blood-based interferon-gamma release assays (IGRAs) are now available and could enhance the estimation of LTBI prevalence in combination with model-based methods. DESIGN We compared conventional and model-based methods for estimating LTBI prevalence among 719 Indian health care workers who underwent both TST and QuantiFERON-TB Gold In-Tube (QFT-G). In addition to using standard cut-off points on TST and QFT-G, Bayesian mixture model analyses were performed with: 1) continuous TST data and 2) categorical data using both TST and QFT-G results in a latent class analysis (LCA), accounting for prior information on sensitivity and specificity. RESULTS Estimates of LTBI prevalence varied from 33.8% to 60.7%, depending on the method used. The mixture model based on TST alone estimated the prevalence at 36.5% (95%CI 28.5–47.0). When results from both tests were combined using LCA, the prevalence was 45.4% (95%CI 39.5–51.1). The LCA provided additional results on the sensitivity, specificity and predictive values of joint results. CONCLUSION The availability of novel, specific IGRAs and development of methods such as mixture analyses allow a more realistic and informative approach to prevalence estimation. PMID:18647448

  17. Improvements in dose accuracy delivered with static-MLC IMRT on an integrated linear accelerator control system.

    Science.gov (United States)

    Li, Ji; Wiersma, Rodney D; Stepaniak, Christopher J; Farrey, Karl J; Al-Hallaq, Hania A

    2012-05-01

    /segment beams at both 300 and 600 MU/min. Earlier generations of Varian LINACs exhibited large dose variations for small MU segments in SMLC-IMRT delivery. Our results confirmed these findings. The dose delivery accuracy for SMLC-IMRT is significantly improved on TrueBeam compared to Trilogy for every combination of low MU/segment (1-10) and high dose rate (200-600 MU/min), in part due to the faster sampling rate (100 vs 20 Hz) and enhanced electronic integration of the MLC controller with the LINAC. SMLC-IMRT can be implemented on TrueBeam with higher dose accuracy per beam (±0.2% vs ±3%) than previous generations of Varian C-series LINACs for 1 MU/segment delivered at 600 MU/min).

  18. Improvements in dose accuracy delivered with static-MLC IMRT on an integrated linear accelerator control system

    Energy Technology Data Exchange (ETDEWEB)

    Li Ji; Wiersma, Rodney D.; Stepaniak, Christopher J.; Farrey, Karl J.; Al-Hallaq, Hania A. [Department of Radiation and Cellular Oncology, University of Chicago, 5758 South Maryland Avenue, MC9006, Chicago, Illinois 60637 (United States)

    2012-05-15

    Trilogy and the TrueBeam up to 10 MU/segment, at all dose rates greater than 100 MU/min. The linear trend of decreasing dose accuracy as a function of increasing dose rate on the Trilogy is no longer apparent on TrueBeam, even for dose rates as high as 2400 MU/min. Dose inaccuracy averaged over all ten segments in each beam delivery sequence was larger for Trilogy than TrueBeam, with the largest discrepancy (0.2% vs 3%) occurring for 1 MU/segment beams at both 300 and 600 MU/min. Conclusions: Earlier generations of Varian LINACs exhibited large dose variations for small MU segments in SMLC-IMRT delivery. Our results confirmed these findings. The dose delivery accuracy for SMLC-IMRT is significantly improved on TrueBeam compared to Trilogy for every combination of low MU/segment (1-10) and high dose rate (200-600 MU/min), in part due to the faster sampling rate (100 vs 20 Hz) and enhanced electronic integration of the MLC controller with the LINAC. SMLC-IMRT can be implemented on TrueBeam with higher dose accuracy per beam ({+-}0.2% vs {+-}3%) than previous generations of Varian C-series LINACs for 1 MU/segment delivered at 600 MU/min).

  19. Evaluation of Resistance to Phytophthora sojae in Soybean Mini Core Collections Using an Improved Assay System.

    Science.gov (United States)

    Jiang, Chang-Jie; Sugano, Shoji; Kaga, Akito; Lee, Sung Shin; Sugimoto, Takuma; Takahashi, Mami; Ishimoto, Masao

    2017-02-01

    Stem and root rot disease caused by Phytophthora sojae is devastating to soybean crops worldwide. Developing host resistance to P. sojae, considered the most effective and stable means to control this disease, is partly hampered by limited germplasm resources. In this study, we first modified conventional methods for a P. sojae resistance assay to a simpler and more cost-effective version, in which the P. sojae inoculum was mixed into the soil and the resistance was evaluated by survival rate (%) of soybean seedlings. This rating had significant correlations (P < 0.01) with the reduction in root fresh weight and the visual root rot severity. Applying this method to evaluate P. sojae resistance in soybean mini core collections comprising either 79 accessions originating from Japan (JMC) or 80 accessions collected around the world (WMC) revealed a wide variation in resistance among the individual varieties. In total, 38 accessions from the JMC and 41 from the WMC exhibited resistance or moderate resistance to P. sojae isolate N1 (with virulence to Rps1b, 3c, 4, 5, and 6), with ≥50% survival. Of these, 26 from the JMC and 29 from the WMC showed at least moderate resistance to P. sojae isolate HR1 (vir Rps1a-c, 1k, 2, 3a-c, 4-6, and 8). Additionally, 24 WCS accessions, in contrast to only 6 from the JMC, exhibited 100% survival after being challenged with both the N1 and HR1 isolates, suggesting a biogeographical difference between the two collections. We further verified two JMC varieties, Daizu and Amagi zairai 90D, for their resistance to an additional four P. sojae isolates (60 to 100% survival), which may provide new and valuable genetic sources for P. sojae resistance breeding in soybean.

  20. Evaluating Landsat 8 Satellite Sensor Data for Improved Vegetation Mapping Accuracy of the New Hampshire Coastal Watershed Area

    Science.gov (United States)

    Ledoux, Lindsay

    the previous Landsat sensor (Landsat 7). Once classification had been performed, traditional and area-based accuracy assessments were implemented. Comparison measures were also calculated (i.e. Kappa, Z test statistic). The results from this study indicate that, while using Landsat 8 imagery is useful, the additional spectral bands provided in the Landsat 8 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) do not provide an improvement in vegetation classification accuracy in this study.

  1. Improving accuracy and efficiency of mutual information for multi-modal retinal image registration using adaptive probability density estimation.

    Science.gov (United States)

    Legg, P A; Rosin, P L; Marshall, D; Morgan, J E

    2013-01-01

    Mutual information (MI) is a popular similarity measure for performing image registration between different modalities. MI makes a statistical comparison between two images by computing the entropy from the probability distribution of the data. Therefore, to obtain an accurate registration it is important to have an accurate estimation of the true underlying probability distribution. Within the statistics literature, many methods have been proposed for finding the 'optimal' probability density, with the aim of improving the estimation by means of optimal histogram bin size selection. This provokes the common question of how many bins should actually be used when constructing a histogram. There is no definitive answer to this. This question itself has received little attention in the MI literature, and yet this issue is critical to the effectiveness of the algorithm. The purpose of this paper is to highlight this fundamental element of the MI algorithm. We present a comprehensive study that introduces methods from statistics literature and incorporates these for image registration. We demonstrate this work for registration of multi-modal retinal images: colour fundus photographs and scanning laser ophthalmoscope images. The registration of these modalities offers significant enhancement to early glaucoma detection, however traditional registration techniques fail to perform sufficiently well. We find that adaptive probability density estimation heavily impacts on registration accuracy and runtime, improving over traditional binning techniques. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Improved Accuracy of Percutaneous Biopsy Using “Cross and Push” Technique for Patients Suspected with Malignant Biliary Strictures

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Prashant, E-mail: p.patel@bham.ac.uk [University of Birmingham, School of Cancer Sciences, Vincent Drive (United Kingdom); Rangarajan, Balaji; Mangat, Kamarjit, E-mail: kamarjit.mangat@uhb.nhs.uk, E-mail: kamarjit.mangat@nhs.net [University Hospital Birmingham NHS Trust, Department of Radiology (United Kingdom)

    2015-08-15

    PurposeVarious methods have been used to sample biliary strictures, including percutaneous fine-needle aspiration biopsy, intraluminal biliary washings, and cytological analysis of drained bile. However, none of these methods has proven to be particularly sensitive in the diagnosis of biliary tract malignancy. We report improved diagnostic accuracy using a modified technique for percutaneous transluminal biopsy in patients with this disease.Materials and MethodsFifty-two patients with obstructive jaundice due to a biliary stricture underwent transluminal forceps biopsy with a modified “cross and push” technique with the use of a flexible biopsy forceps kit commonly used for cardiac biopsies. The modification entailed crossing the stricture with a 0.038-in. wire leading all the way down into the duodenum. A standard or long sheath was subsequently advanced up to the stricture over the wire. A Cook 5.2-Fr biopsy forceps was introduced alongside the wire and the cup was opened upon exiting the sheath. With the biopsy forceps open, within the stricture the sheath was used to push and advance the biopsy cup into the stricture before the cup was closed and the sample obtained. The data were analysed retrospectively.ResultsWe report the outcomes of this modified technique used on 52 consecutive patients with obstructive jaundice secondary to a biliary stricture. The sensitivity and accuracy were 93.3 and 94.2 %, respectively. There was one procedure-related late complication.ConclusionWe propose that the modified “cross and push” technique is a feasible, safe, and more accurate option over the standard technique for sampling strictures of the biliary tree.

  3. MeSHLabeler: improving the accuracy of large-scale MeSH indexing by integrating diverse evidence.

    Science.gov (United States)

    Liu, Ke; Peng, Shengwen; Wu, Junqiu; Zhai, Chengxiang; Mamitsuka, Hiroshi; Zhu, Shanfeng

    2015-06-15

    Medical Subject Headings (MeSHs) are used by National Library of Medicine (NLM) to index almost all citations in MEDLINE, which greatly facilitates the applications of biomedical information retrieval and text mining. To reduce the time and financial cost of manual annotation, NLM has developed a software package, Medical Text Indexer (MTI), for assisting MeSH annotation, which uses k-nearest neighbors (KNN), pattern matching and indexing rules. Other types of information, such as prediction by MeSH classifiers (trained separately), can also be used for automatic MeSH annotation. However, existing methods cannot effectively integrate multiple evidence for MeSH annotation. We propose a novel framework, MeSHLabeler, to integrate multiple evidence for accurate MeSH annotation by using 'learning to rank'. Evidence includes numerous predictions from MeSH classifiers, KNN, pattern matching, MTI and the correlation between different MeSH terms, etc. Each MeSH classifier is trained independently, and thus prediction scores from different classifiers are incomparable. To address this issue, we have developed an effective score normalization procedure to improve the prediction accuracy. MeSHLabeler won the first place in Task 2A of 2014 BioASQ challenge, achieving the Micro F-measure of 0.6248 for 9,040 citations provided by the BioASQ challenge. Note that this accuracy is around 9.15% higher than 0.5724, obtained by MTI. The software is available upon request. © The Author 2015. Published by Oxford University Press.

  4. An improved behavioural assay demonstrates that ultrasound vocalizations constitute a reliable indicator of chronic cancer pain and neuropathic pain

    Directory of Open Access Journals (Sweden)

    Selvaraj Deepitha

    2010-03-01

    Full Text Available Abstract Background On-going pain is one of the most debilitating symptoms associated with a variety of chronic pain disorders. An understanding of mechanisms underlying on-going pain, i.e. stimulus-independent pain has been hampered so far by a lack of behavioural parameters which enable studying it in experimental animals. Ultrasound vocalizations (USVs have been proposed to correlate with pain evoked by an acute activation of nociceptors. However, literature on the utility of USVs as an indicator of chronic pain is very controversial. A majority of these inconsistencies arise from parameters confounding behavioural experiments, which include novelty, fear and stress due to restrain, amongst others. Results We have developed an improved assay which overcomes these confounding factors and enables studying USVs in freely moving mice repetitively over several weeks. Using this improved assay, we report here that USVs increase significantly in mice with bone metastases-induced cancer pain or neuropathic pain for several weeks, in comparison to sham-treated mice. Importantly, analgesic drugs which are known to alleviate tumour pain or neuropathic pain in human patients significantly reduce USVs as well as mechanical allodynia in corresponding mouse models. Conclusions We show that studying USVs and mechanical allodynia in the same cohort of mice enables comparing the temporal progression of on-going pain (i.e. stimulus-independent pain and stimulus-evoked pain in these clinically highly-relevant forms of chronic pain.

  5. Diagnostic accuracy and effectiveness of the Xpert MTB/RIF assay for the diagnosis of HIV-associated lymph node tuberculosis.

    Science.gov (United States)

    Van Rie, A; Page-Shipp, L; Mellet, K; Scott, L; Mkhwnazi, M; Jong, E; Omar, T; Beylis, N; Stevens, W; Sanne, I; Menezes, C N

    2013-11-01

    Xpert MTB/RIF (Xpert) is recommended for human immunodeficiency virus (HIV)-associated pulmonary tuberculosis but not extrapulmonary tuberculosis. We assessed the performance of Xpert for HIV-associated lymph node tuberculosis (LNTB), the most common type of extrapulmonary tuberculosis. Among HIV-infected adults suspected of LNTB presenting for fine needle aspirate (FNA) at a South African hospital, we assessed the diagnostic accuracy of Xpert using either FNA culture or a composite of microscopy, culture, and cytology as the reference standard, and evaluated the impact of different diagnostics on patient management. Among 344 adults with valid FNA culture and Xpert results, 84 (24 %) were positive on microscopy, 149 (43 %) on culture, 152 (53 %) on Xpert, and 181 (57 %) had a cytology result suggestive of tuberculosis. Using liquid culture as the reference standard, the specificity of a single Xpert was suboptimal (88.2 %) but the sensitivity was high [93.3 %, 95 % confidence interval (CI) 87.6-96.6] and increased with decreasing CD4 count (from 87.0 % for CD4 >250 to 98.6 % for CD4 <100 cells/mm(3)). Using a composite reference standard reduced the sensitivity to 79.2 % but increased the specificity to 98.6 %. All Xpert-positive patients initiated treatment within one day, compared to 70 % of culture-positive but Xpert-negative and 13 % of culture- and Xpert-negative but cytology-positive patients. Xpert is accurate and effective and could be endorsed as the initial diagnostic for HIV-associated LNTB.

  6. Temporary shielding of hot spots in the drainage areas of cutaneous melanoma improves accuracy of lymphoscintigraphic sentinel lymph node diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Maza, S.; Valencia, R.; Geworski, L.; Zander, A.; Munz, D.L. [Clinic for Nuclear Medicine, University Hospital Charite, Humboldt University of Berlin, Schumannstrasse 20-21, 10117 Berlin (Germany); Draeger, E.; Winter, H.; Sterry, W. [Clinic for Dermatology, Venereology and Allergology, University Hospital Charite, Humboldt University of Berlin, Berlin (Germany)

    2002-10-01

    Detection of the ''true'' sentinel lymph nodes, permitting correct staging of regional lymph nodes, is essential for management and prognostic assessment in malignant melanoma. In this study, it was prospectively evaluated whether simple temporary shielding of hot spots in lymphatic drainage areas could improve the accuracy of sentinel lymph node diagnostics. In 100 consecutive malignant melanoma patients (45 women, 55 men; age 11-91 years), dynamic and static lymphoscintigraphy in various views was performed after strict intracutaneous application of technetium-99m nanocolloid (40-150 MBq; 0.05 ml/deposit) around the tumour (31 patients) or the biopsy scar (69 patients, safety distance 1 cm). The images were acquired with and without temporary lead shielding of the most prominent hot spots in the drainage area. In 33/100 patients, one or two additional sentinel lymph nodes that showed less tracer accumulation or were smaller (<1.5 cm) were detected after shielding. Four of these patients had metastases in the sentinel lymph nodes; the non-sentinel lymph nodes were tumour negative. In 3/100 patients, hot spots in the drainage area proved to be lymph vessels, lymph vessel intersections or lymph vessel ectasias after temporary shielding; hence, a node interpreted as a non-sentinel lymph node at first glance proved to be the real sentinel lymph node. In two of these patients, lymph node metastasis was histologically confirmed; the non-sentinel lymph nodes were tumour free. In 7/100 patients the exact course of lymph vessels could be mapped after shielding. In one of these patients, two additional sentinel lymph nodes (with metastasis) were detected. Overall, in 43/100 patients the temporary shielding yielded additional information, with sentinel lymph node metastases in 7%. In conclusion, when used in combination with dynamic acquisition in various views, temporary shielding of prominent hot spots in the drainage area of a malignant melanoma of the

  7. Modification of two capripoxvirus quantitative real-time PCR assays to improve diagnostic sensitivity and include beta-actin as an internal positive control.

    Science.gov (United States)

    Das, Amaresh; Deng, Ming Y; Babiuk, Shawn; McIntosh, Michael T

    2017-05-01

    Capripoxviruses (CaPVs), consisting of Sheeppox virus (SPV), Goatpox virus (GPV), and Lumpy skin disease virus (LSDV) species, cause economically significant diseases in sheep, goats, and cattle, respectively. Quantitative real-time polymerase chain reaction (qPCR) assays are routinely used for rapid detection of CaPVs in surveillance and outbreak management programs. We further modified and optimized 2 previously published CaPV qPCR assays, referred to as the Balinsky and Bowden assays, by changing commercial PCR reagents used in the tests. The modified assays displayed 100% analytical specificity and showed no apparent changes in analytical sensitivities for detection of CaPVs compared with the original assays. Diagnostic sensitivities, assessed using 50 clinical reference samples from experimentally infected sheep, goats, and cattle, improved from 82% to 92% for the modified Balinsky assay and from 58% to 82% for the modified Bowden assay. The modified qPCR assays were multiplexed for detection of beta-actin as an indicator for potential false-negative results. The multiplex modified qPCR assays exhibited the same diagnostic sensitivities as the singleplex assays suggesting their utility in the detection of CaPVs.

  8. Evaluation of accuracy and uncertainty of ELISA assays for the determination of interleukin-4, interleukin-5, interferon-gamma and tumor necrosis factor-alpha

    DEFF Research Database (Denmark)

    Borg, Lone; Kristiansen, Jesper; Christensen, Jytte M

    2002-01-01

    , and robustness. Traceability was ensured by the use of World Health Organization International Standards (WHO IS). An uncertainty budget, which combined the contribution from all known uncertainty components, was established for each cytokine ELISA. The between-run relative analytical standard deviation (RSDA...... of the mass concentration of the WHO IS. The uncertainty of the WHO IS was not stated in the accompanying certificate and was evaluated by other means. The largest sources of uncertainty were located outside our laboratory. This means that the possibilities to improve the reliability of the results produced...

  9. The accuracy of survival time prediction for patients with glioma is improved by measuring mitotic spindle checkpoint gene expression.

    Directory of Open Access Journals (Sweden)

    Li Bie

    Full Text Available Identification of gene expression changes that improve prediction of survival time across all glioma grades would be clinically useful. Four Affymetrix GeneChip datasets from the literature, containing data from 771 glioma samples representing all WHO grades and eight normal brain samples, were used in an ANOVA model to screen for transcript changes that correlated with grade. Observations were confirmed and extended using qPCR assays on RNA derived from 38 additional glioma samples and eight normal samples for which survival data were available. RNA levels of eight major mitotic spindle assembly checkpoint (SAC genes (BUB1, BUB1B, BUB3, CENPE, MAD1L1, MAD2L1, CDC20, TTK significantly correlated with glioma grade and six also significantly correlated with survival time. In particular, the level of BUB1B expression was highly correlated with survival time (p<0.0001, and significantly outperformed all other measured parameters, including two standards; WHO grade and MIB-1 (Ki-67 labeling index. Measurement of the expression levels of a small set of SAC genes may complement histological grade and other clinical parameters for predicting survival time.

  10. Transmission Raman measurement directly through packed corn kernels to improve sample representation and accuracy of compositional analysis.

    Science.gov (United States)

    Shin, Kayeong; Chung, Hoeil; Kwak, Chul-won

    2012-08-21

    The potential of transmission Raman spectroscopy for direct analysis of packed granular samples, one of the most frequently encountered sample types in the field of non-destructive spectroscopic analysis, has been evaluated. For this purpose, transmission Raman spectra were collected by laser illumination through packed corn kernels to determine their protein concentration. Back-scattering Raman spectra of the same samples were also collected for comparison. Raman spectral features of the major kernel constituents were initially characterized, and Raman mapping over the whole kernel face was performed to investigate the inhomogeneous distribution of constituents in a kernel. Possible variations of transmission spectral features depending on the laser illumination on different locations of a kernel were investigated, since the orientation of kernels in the packing was essentially random. Rotation of kernel packing during spectral collection was helpful in improving the compositional representation of packed kernels. With partial least squares (PLS) regression, the protein concentrations were determined using both spectral collection methods and the resulting accuracies were compared. As a result, the transmission measurement provided a more accurate determination of protein concentration since it enabled deeper sampling across the packed kernels, leading to a better compositional representation of them. By contrast, in the back-scattering measurement, kernels on the top of the packing were mainly sampled for the spectral acquisition. Moreover, the back-scattering spectral feature, more weighted to constituents localized at the outer portion of a kernel, was short of representing the overall composition of a kernel.

  11. THE EFFECT OF TEACHER, PEER, AND SELF-EDITING ON IMPROVING GRAMMATICAL ACCURACY IN EFL LEARNERS’ WRITING

    Directory of Open Access Journals (Sweden)

    Meysam HEMATI

    2012-11-01

    Full Text Available The aim of this study was to explore the effect of teacher, peer, and self-editing on the improvement of grammatical accuracy in writing, using three groups of participants. The first group engaged in teacher-editing, the second group engaged in peer-editing and the third group engaged in self-editing. The results revealed that, compared to the peer-editing and self-editing groups, the teacher-editing group significantly reduced the rule- based errors in the revised drafts. The results revealed that the performance of the teacher-editing group was better than that of the other two groups, while the performance of the peer-editing group was better than that of the self-editing group regarding the correction of specific language errors in the revised drafts. This study contributes to teaching pedagogy by encouraging teachers to use editing, especially teacher-editing in the writing classroom and to focus on the correction of a few language errors so as to bring about language development.

  12. Multiphysics and Thermal Response Models to Improve Accuracy of Local Temperature Estimation in Rat Cortex under Microwave Exposure

    Directory of Open Access Journals (Sweden)

    Sachiko Kodera

    2017-03-01

    Full Text Available The rapid development of wireless technology has led to widespread concerns regarding adverse human health effects caused by exposure to electromagnetic fields. Temperature elevation in biological bodies is an important factor that can adversely affect health. A thermophysiological model is desired to quantify microwave (MW induced temperature elevations. In this study, parameters related to thermophysiological responses for MW exposures were estimated using an electromagnetic-thermodynamics simulation technique. To the authors’ knowledge, this is the first study in which parameters related to regional cerebral blood flow in a rat model were extracted at a high degree of accuracy through experimental measurements for localized MW exposure at frequencies exceeding 6 GHz. The findings indicate that the improved modeling parameters yield computed results that match well with the measured quantities during and after exposure in rats. It is expected that the computational model will be helpful in estimating the temperature elevation in the rat brain at multiple observation points (that are difficult to measure simultaneously and in explaining the physiological changes in the local cortex region.

  13. Improving the Accuracy of the Hyperspectral Model for Apple Canopy Water Content Prediction using the Equidistant Sampling Method.

    Science.gov (United States)

    Zhao, Huan-San; Zhu, Xi-Cun; Li, Cheng; Wei, Yu; Zhao, Geng-Xing; Jiang, Yuan-Mao

    2017-09-11

    The influence of the equidistant sampling method was explored in a hyperspectral model for the accurate prediction of the water content of apple tree canopy. The relationship between spectral reflectance and water content was explored using the sample partition methods of equidistant sampling and random sampling, and a stepwise regression model of the apple canopy water content was established. The results showed that the random sampling model was Y = 0.4797 - 721787.3883 × Z3 - 766567.1103 × Z5 - 771392.9030 × Z6; the equidistant sampling model was Y = 0.4613 - 480610.4213 × Z2 - 552189.0450 × Z5 - 1006181.8358 × Z6. After verification, the equidistant sampling method was verified to offer a superior prediction ability. The calibration set coefficient of determination of 0.6599 and validation set coefficient of determination of 0.8221 were higher than that of the random sampling model by 9.20% and 10.90%, respectively. The root mean square error (RMSE) of 0.0365 and relative error (RE) of 0.0626 were lower than that of the random sampling model by 17.23% and 17.09%, respectively. Dividing the calibration set and validation set by the equidistant sampling method can improve the prediction accuracy of the hyperspectral model of apple canopy water content.

  14. Does gadolinium-based contrast material improve diagnostic accuracy of local invasion in rectal cancer MRI? A multireader study.

    Science.gov (United States)

    Gollub, Marc J; Lakhman, Yulia; McGinty, Katrina; Weiser, Martin R; Sohn, Michael; Zheng, Junting; Shia, Jinru

    2015-02-01

    OBJECTIVE. The purpose of this study was to compare reader accuracy and agreement on rectal MRI with and without gadolinium administration in the detection of T4 rectal cancer. MATERIALS AND METHODS. In this study, two radiologists and one fellow independently interpreted all posttreatment MRI studies for patients with locally advanced or recurrent rectal cancer using unenhanced images alone or combined with contrast-enhanced images, with a minimum interval of 4 weeks. Readers evaluated involvement of surrounding structures on a 5-point scale and were blinded to pathology and disease stage. Sensitivity, specificity, negative predictive value, positive predictive value, and AUC were calculated and kappa statistics were used to describe interreader agreement. RESULTS. Seventy-two patients (38 men and 34 women) with a mean age of 61 years (range, 32-86 years) were evaluated. Fifteen patients had 32 organs invaded. Global AUCs without and with gadolinium administration were 0.79 and 0.77, 0.91 and 0.86, and 0.83 and 0.78 for readers 1, 2, and 3, respectively. AUCs before and after gadolinium administration were similar. Kappa values before and after gadolinium administration for pairs of readers ranged from 0.5 to 0.7. CONCLUSION. On the basis of pathology as a reference standard, the use of gadolinium during rectal MRI did not significantly improve radiologists' agreement or ability to detect T4 disease.

  15. Novel molecular and computational methods improve the accuracy of insertion site analysis in Sleeping Beauty-induced tumors.

    Directory of Open Access Journals (Sweden)

    Benjamin T Brett

    Full Text Available The recent development of the Sleeping Beauty (SB system has led to the development of novel mouse models of cancer. Unlike spontaneous models, SB causes cancer through the action of mutagenic transposons that are mobilized in the genomes of somatic cells to induce mutations in cancer genes. While previous methods have successfully identified many transposon-tagged mutations in SB-induced tumors, limitations in DNA sequencing technology have prevented a comprehensive analysis of large tumor cohorts. Here we describe a novel method for producing genetic profiles of SB-induced tumors using Illumina sequencing. This method has dramatically increased the number of transposon-induced mutations identified in each tumor sample to reveal a level of genetic complexity much greater than previously appreciated. In addition, Illumina sequencing has allowed us to more precisely determine the depth of sequencing required to obtain a reproducible signature of transposon-induced mutations within tumor samples. The use of Illumina sequencing to characterize SB-induced tumors should significantly reduce sampling error that undoubtedly occurs using previous sequencing methods. As a consequence, the improved accuracy and precision provided by this method will allow candidate cancer genes to be identified with greater confidence. Overall, this method will facilitate ongoing efforts to decipher the genetic complexity of the human cancer genome by providing more accurate comparative information from Sleeping Beauty models of cancer.

  16. An NMR-based scoring function improves the accuracy of binding pose predictions by docking by two orders of magnitude

    Energy Technology Data Exchange (ETDEWEB)

    Orts, Julien [EMBL, Structure and Computational Biology Unit (Germany); Bartoschek, Stefan [Industriepark Hoechst, Sanofi-Aventis Deutschland GmbH, R and D LGCR/Parallel Synthesis and Natural Products (Germany); Griesinger, Christian [Max Planck Institute for Biophysical Chemistry (Germany); Monecke, Peter [Industriepark Hoechst, Sanofi-Aventis Deutschland GmbH, R and D LGCR/Structure, Design and Informatics (Germany); Carlomagno, Teresa, E-mail: teresa.carlomagno@embl.de [EMBL, Structure and Computational Biology Unit (Germany)

    2012-01-15

    Low-affinity ligands can be efficiently optimized into high-affinity drug leads by structure based drug design when atomic-resolution structural information on the protein/ligand complexes is available. In this work we show that the use of a few, easily obtainable, experimental restraints improves the accuracy of the docking experiments by two orders of magnitude. The experimental data are measured in nuclear magnetic resonance spectra and consist of protein-mediated NOEs between two competitively binding ligands. The methodology can be widely applied as the data are readily obtained for low-affinity ligands in the presence of non-labelled receptor at low concentration. The experimental inter-ligand NOEs are efficiently used to filter and rank complex model structures that have been pre-selected by docking protocols. This approach dramatically reduces the degeneracy and inaccuracy of the chosen model in docking experiments, is robust with respect to inaccuracy of the structural model used to represent the free receptor and is suitable for high-throughput docking campaigns.

  17. An NMR-based scoring function improves the accuracy of binding pose predictions by docking by two orders of magnitude.

    Science.gov (United States)

    Orts, Julien; Bartoschek, Stefan; Griesinger, Christian; Monecke, Peter; Carlomagno, Teresa

    2012-01-01

    Low-affinity ligands can be efficiently optimized into high-affinity drug leads by structure based drug design when atomic-resolution structural information on the protein/ligand complexes is available. In this work we show that the use of a few, easily obtainable, experimental restraints improves the accuracy of the docking experiments by two orders of magnitude. The experimental data are measured in nuclear magnetic resonance spectra and consist of protein-mediated NOEs between two competitively binding ligands. The methodology can be widely applied as the data are readily obtained for low-affinity ligands in the presence of non-labelled receptor at low concentration. The experimental inter-ligand NOEs are efficiently used to filter and rank complex model structures that have been pre-selected by docking protocols. This approach dramatically reduces the degeneracy and inaccuracy of the chosen model in docking experiments, is robust with respect to inaccuracy of the structural model used to represent the free receptor and is suitable for high-throughput docking campaigns.

  18. Improved accuracy of pulmonary embolism computer-aided detection using iterative reconstruction compared with filtered back projection.

    Science.gov (United States)

    Lahiji, Kian; Kligerman, Seth; Jeudy, Jean; White, Charles

    2014-10-01

    The purpose of this study was to determine whether use of iterative reconstruction (IR) can improve performance of a pulmonary embolism computer-aided detection (PE CAD) prototype. Images were collected from 40 consecutive pulmonary CT angiographic examinations in which PE was found and 26 studies in which it was not found for use as control cases. All images were reconstructed with filtered back projection (FBP) and six levels of a hybrid IR algorithm. The studies were evaluated with a prototype PE CAD system, and its performance was comparatively assessed on the basis of reconstruction type on a per-embolus and a per-study basis. Use of the hybrid IR algorithm led to a significant and progressive decrease in false-positive marks made by PE CAD compared with those made by radiologists on FBP reconstructions (239 false-positive marks for FBP and 154, 136, 125, 116, 107, and 98 false-positive marks for the six hybrid IR [HIR] levels). Specificity improved with increasing HIR level (45.6% for level 6; 30.3% for FBP). However, compared with FBP, increasing levels of HIR resulted in a progressive decrease in per-embolism sensitivity (70.3% for FBP; 55.4% for HIR level 6) and, with the exception of HIR level 4, a progressive decrease in per-study sensitivity (97.5% for FBP; 85.0% for HIR level 6). Overall accuracy was highest for HIR level 1 (77.3%). The use of IR leads to a significant reduction in false-positive marks by PE CAD at a cost of decreasing sensitivity. Very high levels of IR, which had the lowest sensitivities, should be avoided if being used concomitantly with PE CAD.

  19. Improvement of 96-well microplate assay for estimation of cell growth and inhibition of Leishmania with Alamar Blue.

    Science.gov (United States)

    Corral, María Jesús; González, Elena; Cuquerella, Montserrat; Alunda, José María

    2013-08-01

    The value of resazurin-based Alamar Blue redox indicator to determine multiplication of Leishmania promastigotes in 96-well microtiter plates was examined. In addition, assay was validated with amphotericin B (AmB) and allicin. The method was tested on L.donovani and L.infantum promastigotes under different culture conditions (variable air-phase, presence of phenol red, initial cell density, incubation time, use of Hepes buffer). Results showed that the gas-phase of promastigote cultures was critical. The method yielded consistent results with initial plating cell densities of 2.5 × 10⁵ promastigotes/well, up to 72 h incubation and 5% CO₂ atmosphere or reduced air availability (sealed plastic bags, film-sealed microplates). Detection of low numbers of promastigotes and earlier results could be obtained using fluorimetry instead of spectrophotometry. The addition of 20 mM Hepes improved the results. Fluorescence intensity correlated to promastigotes number in both Leishmania spp. Inhibitory concentration (IC₅₀) values for AmB and allicin using cell counting and fluorimetry were comparable. Under these conditions this one-step, low-cost redox indicator can be used in drug sensitivity assays and studies of differential proliferation rates of Leishmania isolates or strains in a 96-well format. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. A Method for Improving the Pose Accuracy of a Robot Manipulator Based on Multi-Sensor Combined Measurement and Data Fusion

    Directory of Open Access Journals (Sweden)

    Bailing Liu

    2015-04-01

    Full Text Available An improvement method for the pose accuracy of a robot manipulator by using a multiple-sensor combination measuring system (MCMS is presented. It is composed of a visual sensor, an angle sensor and a series robot. The visual sensor is utilized to measure the position of the manipulator in real time, and the angle sensor is rigidly attached to the manipulator to obtain its orientation. Due to the higher accuracy of the multi-sensor, two efficient data fusion approaches, the Kalman filter (KF and multi-sensor optimal information fusion algorithm (MOIFA, are used to fuse the position and orientation of the manipulator. The simulation and experimental results show that the pose accuracy of the robot manipulator is improved dramatically by 38%~78% with the multi-sensor data fusion. Comparing with reported pose accuracy improvement methods, the primary advantage of this method is that it does not require the complex solution of the kinematics parameter equations, increase of the motion constraints and the complicated procedures of the traditional vision-based methods. It makes the robot processing more autonomous and accurate. To improve the reliability and accuracy of the pose measurements of MCMS, the visual sensor repeatability is experimentally studied. An optimal range of 1 x 0.8 x 1 ~ 2 x 0.8 x 1  m in the field of view (FOV is indicated by the experimental results.

  1. High accuracy mass spectrometry analysis as a tool to verify and improve gene annotation using Mycobacterium tuberculosis as an example

    Directory of Open Access Journals (Sweden)

    Prasad Swati

    2008-07-01

    Full Text Available Abstract Background While the genomic annotations of diverse lineages of the Mycobacterium tuberculosis complex are available, divergences between gene prediction methods are still a challenge for unbiased protein dataset generation. M. tuberculosis gene annotation is an example, where the most used datasets from two independent institutions (Sanger Institute and Institute of Genomic Research-TIGR differ up to 12% in the number of annotated open reading frames, and 46% of the genes contained in both annotations have different start codons. Such differences emphasize the importance of the identification of the sequence of protein products to validate each gene annotation including its sequence coding area. Results With this objective, we submitted a culture filtrate sample from M. tuberculosis to a high-accuracy LTQ-Orbitrap mass spectrometer analysis and applied refined N-terminal prediction to perform comparison of two gene annotations. From a total of 449 proteins identified from the MS data, we validated 35 tryptic peptides that were specific to one of the two datasets, representing 24 different proteins. From those, 5 proteins were only annotated in the Sanger database. In the remaining proteins, the observed differences were due to differences in annotation of transcriptional start sites. Conclusion Our results indicate that, even in a less complex sample likely to represent only 10% of the bacterial proteome, we were still able to detect major differences between different gene annotation approaches. This gives hope that high-throughput proteomics techniques can be used to improve and validate gene annotations, and in particular for verification of high-throughput, automatic gene annotations.

  2. SU-F-J-182: Investigation of Systems for Improved Accuracy in Clinical Y-90 Percent Delivered Calculations

    Energy Technology Data Exchange (ETDEWEB)

    McBeth, R; Elder, D [University of Colorado Health, Aurora, CO (United States); Kesner, A [University of Colorado, Anschutz Medical Campus, Aurora, CO (United States)

    2016-06-15

    Purpose: Y-90 Selective Internal Radiation Therapy (SIRT) is used to treat liver tumors, and by nature has variability in the percent of the intended dose that is actually delivered. To determine the quality of the administration, pre and post activity measurements are taken, and used to infer percent delivered. Vendor specifications indicate the use of an ion chamber to take these measurements. In our work, we investigated the accuracy of ion chambers, and compared them to other detector systems. Methods: We have built phantoms, phantom holders, and protocols, which allow us to measure our Y90 doses with varying apparatuses: a dose calibrator, a Geiger-counter, an ion chamber, a crystal based thyroid probe, and a gamma camera. We have set up a system that has enabled us to gather data by measuring clinical Y90 doses as they are used in the clinic using all of the instrumental methods. Five initial doses (25 measurements/acquisitions) have been taken at the time of this abstract submission. Results: Our initial results show that measurements acquired using scintillation based detectors (thyroid probe and gamma camera) correlate better with the gold standard (i.e. the dose calibrator). Pearson correlations between the dose calibrator measurements and the GM counter, Ion chamber, thyroid probe, and gamma camera were found to be 0.88, 0.83, 0.98, 0.99, respectively. More acquisitions and analysis are planned to determine the precision of the systems, as well as optimal energy window settings. Conclusion: It is likely that current standard practice can be improved using scintillation crystal based detectors. Such systems are more sensitive, can integrate signal, and can use energy discrimination. Furthermore, phantoms can be built to integrate with probe and gamma camera systems that are robust and provide reproducibility. Future work will include expanded acquisition and analysis.

  3. EGNSS High Accuracy System Improving Photovoltaic Plant Maintenance using RPAS integrated with Low-cost RTK Receiver

    DEFF Research Database (Denmark)

    Nisi, Marco; Menichetti, Fabio; Bilal, Muhammad

    Global Navigation Satellite System (GNSS) Real Time Kinematic (RTK) is the key enabling technology for a number of applications demanding very high positioning accuracy as their operational requirement. This include, but not limited to, mapping, surveying, robot guidance, and precision agriculture...... to name a few. Typically, GNSS RTK employs high-end dual-frequency receivers and antennas to deliver precise positioning that, in some way, restricts the use of GNSS RTK to a subset of user market due to very high cost. The emerging mass-market user applications, however, require centimeter positioning...... accuracy considering a cost-effective solution. This calls for low-cost GNSS RTK technology to create new possibilities for mass-market user applications to make use of GNSS high accuracy positioning in a variety of ways. One of the applications that make use of low-cost RTK is EGNSS high accuracy system...

  4. Development and inter-laboratory validation study of an improved new real-time PCR assay with internal control for detection and laboratory diagnosis of African swine fever virus.

    Science.gov (United States)

    Tignon, Marylène; Gallardo, Carmina; Iscaro, Carmen; Hutet, Evelyne; Van der Stede, Yves; Kolbasov, Denis; De Mia, Gian Mario; Le Potier, Marie-Frédérique; Bishop, Richard P; Arias, Marisa; Koenen, Frank

    2011-12-01

    A real-time polymerase chain reaction (PCR) assay for the rapid detection of African swine fever virus (ASFV), multiplexed for simultaneous detection of swine beta-actin as an endogenous control, has been developed and validated by four National Reference Laboratories of the European Union for African swine fever (ASF) including the European Union Reference Laboratory. Primers and a TaqMan(®) probe specific for ASFV were selected from conserved regions of the p72 gene. The limit of detection of the new real-time PCR assay is 5.7-57 copies of the ASFV genome. High accuracy, reproducibility and robustness of the PCR assay (CV ranging from 0.7 to 5.4%) were demonstrated both within and between laboratories using different real-time PCR equipments. The specificity of virus detection was validated using a panel of 44 isolates collected over many years in various geographical locations in Europe, Africa and America, including recent isolates from the Caucasus region, Sardinia, East and West Africa. Compared to the OIE-prescribed conventional and real-time PCR assays, the sensitivity of the new assay with internal control was improved, as demonstrated by testing 281 field samples collected in recent outbreaks and surveillance areas in Europe and Africa (170 samples) together with samples obtained through experimental infections (111 samples). This is particularly evident in the early days following experimental infection and during the course of the disease in pigs sub-clinically infected with strains of low virulence (from 35 up to 70dpi). The specificity of the assay was also confirmed on 150 samples from uninfected pigs and wild boar from ASF-free areas. Measured on the total of 431 tested samples, the positive deviation of the new assay reaches 21% or 26% compared to PCR and real-time PCR methods recommended by OIE. This improved and rigorously validated real-time PCR assay with internal control will provide a rapid, sensitive and reliable molecular tool for ASFV

  5. Improving the Accuracy of Computer-aided Diagnosis for Breast MR Imaging by Differentiating between Mass and Nonmass Lesions.

    Science.gov (United States)

    Gallego-Ortiz, Cristina; Martel, Anne L

    2016-03-01

    To determine suitable features and optimal classifier design for a computer-aided diagnosis (CAD) system to differentiate among mass and nonmass enhancements during dynamic contrast material-enhanced magnetic resonance (MR) imaging of the breast. Two hundred eighty histologically proved mass lesions and 129 histologically proved nonmass lesions from MR imaging studies were retrospectively collected. The institutional research ethics board approved this study and waived informed consent. Breast Imaging Reporting and Data System classification of mass and nonmass enhancement was obtained from radiologic reports. Image data from dynamic contrast-enhanced MR imaging were extracted and analyzed by using feature selection techniques and binary, multiclass, and cascade classifiers. Performance was assessed by measuring the area under the receiver operating characteristics curve (AUC), sensitivity, and specificity. Bootstrap cross validation was used to predict the best classifier for the classification task of mass and nonmass benign and malignant breast lesions. A total of 176 features were extracted. Feature relevance ranking indicated unequal importance of kinetic, texture, and morphologic features for mass and nonmass lesions. The best classifier performance was a two-stage cascade classifier (mass vs nonmass followed by malignant vs benign classification) (AUC, 0.91; 95% confidence interval (CI): 0.88, 0.94) compared with one-shot classifier (ie, all benign vs malignant classification) (AUC, 0.89; 95% CI: 0.85, 0.92). The AUC was 2% higher for cascade (median percent difference obtained by using paired bootstrapped samples) and was significant (P = .0027). Our proposed two-stage cascade classifier decreases the overall misclassification rate by 12%, with 72 of 409 missed diagnoses with cascade versus 82 of 409 missed diagnoses with one-shot classifier. Separately optimizing feature selection and training classifiers for mass and nonmass lesions improves the accuracy

  6. Development of Phage Lysin LysA2 for Use in Improved Purity Assays for Live Biotherapeutic Products.

    Science.gov (United States)

    Dreher-Lesnick, Sheila M; Schreier, Jeremy E; Stibitz, Scott

    2015-12-16

    Live biotherapeutic products (LBPs), commonly referred to as probiotics, are typically preparations of live bacteria, such as Lactobacillus and Bifidobacterium species that are considered normal human commensals. Popular interest in probiotics has been increasing with general health benefits being attributed to their consumption, but there is also growing interest in evaluating such products for treatment of specific diseases. While over-the-counter probiotics are generally viewed as very safe, at least in healthy individuals, it must be remembered that clinical studies to assess these products may be done in individuals whose defenses are compromised, such as through a disease process, immunosuppressive clinical treatment, or an immature or aging immune system. One of the major safety criteria for LBPs used in clinical studies is microbial purity, i.e., the absence of extraneous, undesirable microorganisms. The main goal of this project is to develop recombinant phage lysins as reagents for improved purity assays for LBPs. Phage lysins are hydrolytic enzymes containing a cell binding domain that provides specificity and a catalytic domain responsible for lysis and killing. Our approach is to use recombinant phage lysins to selectively kill target product bacteria, which when used for purity assays will allow for outgrowth of potential contaminants under non-selective conditions, thus allowing an unbiased assessment of the presence of contaminants. To develop our approach, we used LysA2, a phage lysin with reported activity against a broad range of Lactobacillus species. We report the lytic profile of a non-tagged recombinant LysA2 against Lactobacillus strains in our collection. We also present a proof-of-concept experiment, showing that addition of partially purified LysA2 to a culture of Lactobacillus jensenii (L. jensenii) spiked with low numbers of Escherichia coli (E. coli) or Staphylococcus aureus (S. aureus ) effectively eliminates or knocks down L

  7. Improving risk stratification among veterans diagnosed with prostate cancer: impact of the 17-gene prostate score assay.

    Science.gov (United States)

    Lynch, Julie A; Rothney, Megan P; Salup, Raoul R; Ercole, Cesar E; Mathur, Sharad C; Duchene, David A; Basler, Joseph W; Hernandez, Javier; Liss, Michael A; Porter, Michael P; Wright, Jonathan L; Risk, Michael C; Garzotto, Mark; Efimova, Olga; Barrett, Laurie; Berse, Brygida; Kemeter, Michael J; Febbo, Phillip G; Dash, Atreya

    2018-01-01

    Active surveillance (AS) has been widely implemented within Veterans Affairs' medical centers (VAMCs) as a standard of care for low-risk prostate cancer (PCa). Patient characteristics such as age, race, and Agent Orange (AO) exposure may influence advisability of AS in veterans. The 17-gene assay may improve risk stratification and management selection. To compare management strategies for PCa at 6 VAMCs before and after introduction of the Oncotype DX Genomic Prostate Score (GPS) assay. We reviewed records of patients diagnosed with PCa between 2013 and 2014 to identify management patterns in an untested cohort. From 2015 to 2016, these patients received GPS testing in a prospective study. Charts from 6 months post biopsy were reviewed for both cohorts to compare management received in the untested and tested cohorts. Men who just received their diagnosis and have National Comprehensive Cancer Network (NCCN) very low-, low-, and select cases of intermediate-risk PCa. Patient characteristics were generally similar in the untested and tested cohorts. AS utilization was 12% higher in the tested cohort compared with the untested cohort. In men younger than 60 years, utilization of AS in tested men was 33% higher than in untested men. AS in tested men was higher across all NCCN risk groups and races, particular in low-risk men (72% vs 90% for untested vs tested, respectively). Tested veterans exposed to AO received less AS than untested veterans. Tested nonexposed veterans received 19% more AS than untested veterans. Median GPS results did not significantly differ as a factor of race or AO exposure. Men who receive GPS testing are more likely to utilize AS within the year post diagnosis, regardless of age, race, and NCCN risk group. Median GPS was similar across racial groups and AO exposure groups, suggesting similar biology across these groups. The GPS assay may be a useful tool to refine risk assessment of PCa and increase rates of AS among clinically and

  8. Development of Phage Lysin LysA2 for Use in Improved Purity Assays for Live Biotherapeutic Products

    Directory of Open Access Journals (Sweden)

    Sheila M. Dreher-Lesnick

    2015-12-01

    Full Text Available Live biotherapeutic products (LBPs, commonly referred to as probiotics, are typically preparations of live bacteria, such as Lactobacillus and Bifidobacterium species that are considered normal human commensals. Popular interest in probiotics has been increasing with general health benefits being attributed to their consumption, but there is also growing interest in evaluating such products for treatment of specific diseases. While over-the-counter probiotics are generally viewed as very safe, at least in healthy individuals, it must be remembered that clinical studies to assess these products may be done in individuals whose defenses are compromised, such as through a disease process, immunosuppressive clinical treatment, or an immature or aging immune system. One of the major safety criteria for LBPs used in clinical studies is microbial purity, i.e., the absence of extraneous, undesirable microorganisms. The main goal of this project is to develop recombinant phage lysins as reagents for improved purity assays for LBPs. Phage lysins are hydrolytic enzymes containing a cell binding domain that provides specificity and a catalytic domain responsible for lysis and killing. Our approach is to use recombinant phage lysins to selectively kill target product bacteria, which when used for purity assays will allow for outgrowth of potential contaminants under non-selective conditions, thus allowing an unbiased assessment of the presence of contaminants. To develop our approach, we used LysA2, a phage lysin with reported activity against a broad range of Lactobacillus species. We report the lytic profile of a non-tagged recombinant LysA2 against Lactobacillus strains in our collection. We also present a proof-of-concept experiment, showing that addition of partially purified LysA2 to a culture of Lactobacillus jensenii (L. jensenii spiked with low numbers of Escherichia coli (E. coli or Staphylococcus aureus (S. aureus effectively eliminates or knocks

  9. Use of temperature dependent Raman spectra to improve accuracy for analysis of complex oil-based samples: lube base oils and adulterated olive oils.

    Science.gov (United States)

    Kim, Mooeung; Lee, Sanguk; Chang, Kyeol; Chung, Hoeil; Jung, Young Mee

    2012-10-20

    A simple and effective strategy to improve accuracy for Raman spectroscopic analysis of complex mixture samples by probing a measurement temperature yielding enhanced spectral selectivity has been demonstrated. For the evaluation, the determination of Kinematic Viscosity at 40 °C (KV@40) of lube base oil (LBO) samples was initially attempted. Partial least squares (PLS) was used to determine the KV@40 using Raman spectra of the samples collected at 8 different temperatures from 20 to 90 °C with 10 °C increments. Interestingly, the distinct temperature-induced spectral variation among the samples occurred at 50 °C, thereby resulting in the improved accuracy for determination of KV@40. Two-dimensional (2D) correlation analysis was also performed to find an additional supportive rationale for the improved accuracy. The strategy was further evaluated for the identification of soybean oil-adulterated olive oils using linear discriminant analysis (LDA). Similarly, the discrimination accuracy was improved around 80-90 °C due to the enhanced spectral selectivity between olive and soybean oils. In overall, these two results successfully demonstrate analytical effectiveness of the strategy. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. A Bayesian taxonomic classification method for 16S rRNA gene sequences with improved species-level accuracy.

    Science.gov (United States)

    Gao, Xiang; Lin, Huaiying; Revanna, Kashi; Dong, Qunfeng

    2017-05-10

    Species-level classification for 16S rRNA gene sequences remains a serious challenge for microbiome researchers, because existing taxonomic classification tools for 16S rRNA gene sequences either do not provide species-level classification, or their classification results are unreliable. The unreliable results are due to the limitations in the existing methods which either lack solid probabilistic-based criteria to evaluate the confidence of their taxonomic assignments, or use nucleotide k-mer frequency as the proxy for sequence similarity measurement. We have developed a method that shows significantly improved species-level classification results over existing methods. Our method calculates true sequence similarity between query sequences and database hits using pairwise sequence alignment. Taxonomic classifications are assigned from the species to the phylum levels based on the lowest common ancestors of multiple database hits for each query sequence, and further classification reliabilities are evaluated by bootstrap confidence scores. The novelty of our method is that the contribution of each database hit to the taxonomic assignment of the query sequence is weighted by a Bayesian posterior probability based upon the degree of sequence similarity of the database hit to the query sequence. Our method does not need any training datasets specific for different taxonomic groups. Instead only a reference database is required for aligning to the query sequences, making our method easily applicable for different regions of the 16S rRNA gene or other phylogenetic marker genes. Reliable species-level classification for 16S rRNA or other phylogenetic marker genes is critical for microbiome research. Our software shows significantly higher classification accuracy than the existing tools and we provide probabilistic-based confidence scores to evaluate the reliability of our taxonomic classification assignments based on multiple database matches to query sequences. Despite

  11. Improving the quantitative accuracy of optical-emission computed tomography by incorporating an attenuation correction: application to HIF1 imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, E; Bowsher, J; Thomas, A S; Sakhalkar, H; Dewhirst, M; Oldham, M [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States)

    2008-10-07

    Optical computed tomography (optical-CT) and optical-emission computed tomography (optical-ECT) are new techniques for imaging the 3D structure and function (including gene expression) of whole unsectioned tissue samples. This work presents a method of improving the quantitative accuracy of optical-ECT by correcting for the 'self'-attenuation of photons emitted within the sample. The correction is analogous to a method commonly applied in single-photon-emission computed tomography reconstruction. The performance of the correction method was investigated by application to a transparent cylindrical gelatin phantom, containing a known distribution of attenuation (a central ink-doped gelatine core) and a known distribution of fluorescing fibres. Attenuation corrected and uncorrected optical-ECT images were reconstructed on the phantom to enable an evaluation of the effectiveness of the correction. Significant attenuation artefacts were observed in the uncorrected images where the central fibre appeared {approx}24% less intense due to greater attenuation from the surrounding ink-doped gelatin. This artefact was almost completely removed in the attenuation-corrected image, where the central fibre was within {approx}4% of the others. The successful phantom test enabled application of attenuation correction to optical-ECT images of an unsectioned human breast xenograft tumour grown subcutaneously on the hind leg of a nude mouse. This tumour cell line had been genetically labelled (pre-implantation) with fluorescent reporter genes such that all viable tumour cells expressed constitutive red fluorescent protein and hypoxia-inducible factor 1 transcription-produced green fluorescent protein. In addition to the fluorescent reporter labelling of gene expression, the tumour microvasculature was labelled by a light-absorbing vasculature contrast agent delivered in vivo by tail-vein injection. Optical-CT transmission images yielded high-resolution 3D images of the

  12. Use of Low-Level Sensor Data to Improve the Accuracy of Bluetooth-Based Travel Time Estimation

    DEFF Research Database (Denmark)

    Araghi, Bahar Namaki; Christensen, Lars Tørholm; Krishnan, Rajesh

    2013-01-01

    by a single device. The latter situation could lead to location ambiguity and could reduce the accuracy of travel time estimation. Therefore, the accuracy of travel time estimation by Bluetooth technology depends on how location ambiguity is handled by the estimation method. The issue of multiple detection...... events in the context of travel time estimation by Bluetooth technology has been considered by various researchers. However, treatment of this issue has been simplistic. Most previous studies have used the first detection event (enter-enter) as the best estimate. No systematic analysis has been conducted...... to explore the most accurate method of travel time estimation with multiple detection events. In this study, different aspects of the Bluetooth detection zone, including size and impact on the accuracy of travel time estimation, were discussed. Four methods were applied to estimate travel time: enter...

  13. Canopy Temperature and Vegetation Indices from High-Throughput Phenotyping Improve Accuracy of Pedigree and Genomic Selection for Grain Yield in Wheat.

    Science.gov (United States)

    Rutkoski, Jessica; Poland, Jesse; Mondal, Suchismita; Autrique, Enrique; Pérez, Lorena González; Crossa, José; Reynolds, Matthew; Singh, Ravi

    2016-09-08

    Genomic selection can be applied prior to phenotyping, enabling shorter breeding cycles and greater rates of genetic gain relative to phenotypic selection. Traits measured using high-throughput phenotyping based on proximal or remote sensing could be useful for improving pedigree and genomic prediction model accuracies for traits not yet possible to phenotype directly. We tested if using aerial measurements of canopy temperature, and green and red normalized difference vegetation index as secondary traits in pedigree and genomic best linear unbiased prediction models could increase accuracy for grain yield in wheat, Triticum aestivum L., using 557 lines in five environments. Secondary traits on training and test sets, and grain yield on the training set were modeled as multivariate, and compared to univariate models with grain yield on the training set only. Cross validation accuracies were estimated within and across-environment, with and without replication, and with and without correcting for days to heading. We observed that, within environment, with unreplicated secondary trait data, and without correcting for days to heading, secondary traits increased accuracies for grain yield by 56% in pedigree, and 70% in genomic prediction models, on average. Secondary traits increased accuracy slightly more when replicated, and considerably less when models corrected for days to heading. In across-environment prediction, trends were similar but less consistent. These results show that secondary traits measured in high-throughput could be used in pedigree and genomic prediction to improve accuracy. This approach could improve selection in wheat during early stages if validated in early-generation breeding plots. Copyright © 2016 Rutkoski et al.

  14. Canopy Temperature and Vegetation Indices from High-Throughput Phenotyping Improve Accuracy of Pedigree and Genomic Selection for Grain Yield in Wheat

    Directory of Open Access Journals (Sweden)

    Jessica Rutkoski

    2016-09-01

    Full Text Available Genomic selection can be applied prior to phenotyping, enabling shorter breeding cycles and greater rates of genetic gain relative to phenotypic selection. Traits measured using high-throughput phenotyping based on proximal or remote sensing could be useful for improving pedigree and genomic prediction model accuracies for traits not yet possible to phenotype directly. We tested if using aerial measurements of canopy temperature, and green and red normalized difference vegetation index as secondary traits in pedigree and genomic best linear unbiased prediction models could increase accuracy for grain yield in wheat, Triticum aestivum L., using 557 lines in five environments. Secondary traits on training and test sets, and grain yield on the training set were modeled as multivariate, and compared to univariate models with grain yield on the training set only. Cross validation accuracies were estimated within and across-environment, with and without replication, and with and without correcting for days to heading. We observed that, within environment, with unreplicated secondary trait data, and without correcting for days to heading, secondary traits increased accuracies for grain yield by 56% in pedigree, and 70% in genomic prediction models, on average. Secondary traits increased accuracy slightly more when replicated, and considerably less when models corrected for days to heading. In across-environment prediction, trends were similar but less consistent. These results show that secondary traits measured in high-throughput could be used in pedigree and genomic prediction to improve accuracy. This approach could improve selection in wheat during early stages if validated in early-generation breeding plots.

  15. Development of C-reactive protein certified reference material NMIJ CRM 6201-b: optimization of a hydrolysis process to improve the accuracy of amino acid analysis.

    Science.gov (United States)

    Kato, Megumi; Kinumi, Tomoya; Yoshioka, Mariko; Goto, Mari; Fujii, Shin-Ichiro; Takatsu, Akiko

    2015-04-01

    To standardize C-reactive protein (CRP) assays, the National Metrology Institute of Japan (NMIJ) has developed a C-reactive protein solution certified reference material, CRM 6201-b, which is intended for use as a primary reference material to enable the SI-traceable measurement of CRP. This study describes the development process of CRM 6201-b. As a candidate material of the CRM, recombinant human CRP solution was selected because of its higher purity and homogeneity than the purified material from human serum. Gel filtration chromatography was used to examine the homogeneity and stability of the present CRM. The total protein concentration of CRP in the present CRM was determined by amino acid analysis coupled to isotope-dilution mass spectrometry (IDMS-AAA). To improve the accuracy of IDMS-AAA, we optimized the hydrolysis process by examining the effect of parameters such as the volume of protein samples taken for hydrolysis, the procedure of sample preparation prior to the hydrolysis, hydrolysis temperature, and hydrolysis time. Under optimized conditions, we conducted two independent approaches in which the following independent hydrolysis and liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) were combined: one was vapor-phase acid hydrolysis (130 °C, 24 h) and hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS) method, and the other was microwave-assisted liquid-phase acid hydrolysis (150 °C, 3 h) and pre-column derivatization liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The quantitative values of the two different amino acid analyses were in agreement within their uncertainties. The certified value was the weighted mean of the results of the two methods. Uncertainties from the value-assignment method, between-method variance, homogeneity, long-term stability, and short-term stability were taken into account in evaluating the uncertainty for a certified value. The certified value and the

  16. The Impact of Implicit Tasks on Improving the Learners' Writing in Terms of Autonomy and Grammatical Accuracy

    Science.gov (United States)

    Nazari, Nastaran

    2014-01-01

    This paper aims to explore the Iranian EFL (English as a Foreign Language) learners' ability to gain grammatical accuracy in their writing by noticing and correcting their own grammatical errors. Recent literature in language acquisition has emphasized the role of implicit tasks in encouraging learners to develop autonomous language learning…

  17. EpCAM-based flow cytometry in cerebrospinal fluid greatly improves diagnostic accuracy of leptomeningeal metastases from epithelial tumors

    NARCIS (Netherlands)

    Milojkovic Kerklaan, B.; Pluim, Dick; Bol, Mijke; Hofland, Ingrid; Westerga, Johan; van Tinteren, Harm; Beijnen, Jos H; Boogerd, Willem; Schellens, Jan H M; Brandsma, Dieta

    BACKGROUND: Moderate diagnostic accuracy of MRI and initial cerebrospinal fluid (CSF) cytology analysis results in at least 10%-15% false negative diagnoses of leptomeningeal metastases (LM) of solid tumors, thus postponing start of therapy. The aim of this prospective clinical study was to

  18. Short communication: Improving accuracy of Jersey genomic evaluations in the United States and Denmark by sharing reference population bulls

    Science.gov (United States)

    The effect on prediction accuracy for Jersey genomic evaluations in Denmark and the United States from using larger reference populations was assessed. Each country contributed genotypes from 1,157 Jersey bulls to the reference population of the other. Eight of 9 traits analyzed by Denmark (milk, fa...

  19. Improved accuracy of genomic prediction for dry matter intake of dairy cattle from combined European and Australian data sets

    NARCIS (Netherlands)

    Haas, de Y.; Calus, M.P.L.; Veerkamp, R.F.; Wall, E.; Coffey, M.P.; Daetwyler, H.D.; Hayes, B.J.; Pryce, J.

    2012-01-01

    With the aim of increasing the accuracy of genomic estimated breeding values for dry matter intake (DMI) in dairy cattle, data from Australia (AU), the United Kingdom (UK), and the Netherlands (NL) were combined using both single-trait and multi-trait models. In total, DMI records were available on

  20. Improved enzyme-linked immunoadsorbent assay (ELISA for the study of Trypanosoma cruzi-host cell interaction in vitro

    Directory of Open Access Journals (Sweden)

    Mauricio R. M. P. Luz

    1993-06-01

    Full Text Available We herein present an improved assay for detecting the presence of Trypanosoma cruzi in infected cultures. Using chagasic human sera (CHS, we were able to detect T. cruzi infection in primary cultures of both peritoneal macrophages and heart muscle cells (MHC. To avoid elevated background levels - hitherto observed in all experiments especially in those using HMC - CHS were preincubated with uninfected cells in monolayers or suspensions prior to being used for detection of T. cruzi in infected monolayers. Preincubation with cell suspensions gave better results than with monolayers, reducing background by up to three times and increasing sensitivity by to twenty times. In addition, the continous fibroplastic cell line L929 was shown to be suitable for preadsorption of CHS. These results indicate that the high background levels observed in previous reports may be due to the presence of human autoantibodies that recognize surface and/or extracellular matrix components in cell monolayers. We therefore propose a modified procedure that increases the performance of the ELISA method, making it an useful tool even in cultures that would otherwise be expected to present low levels of infection or high levels of background

  1. An improved enzyme-linked immunosorbent assay for whole-cell determination of methanogens in samples from anaerobic reactors

    DEFF Research Database (Denmark)

    Sørensen, A.H.; Ahring, B.K.

    1997-01-01

    -quality microtiter plates and the addition of dilute hydrochloric acid to the samples. In an experiment on different digester samples, the test demonstrated a unique pattern of different methanogenic strains present in each sample. The limited preparatory work required for the assay and the simple assay design make...

  2. Improving contour accuracy and strength of reactive air brazed (RAB) ceramic/metal joints by controlling interface microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chichi; Kuhn, Bernd; Brandenberg, Joerg; Beck, Tilmann; Singheiser, Lorenz [Forschungszentrum Juelich GmbH, Institute for Energy and Climate Research (IEK), Microstructure and Properties of Materials (IEK-2), 52425 Juelich (Germany); Bobzin, Kirsten; Bagcivan, Nazlim; Kopp, Nils [Surface Engineering Institute (IOT), RWTH Aachen University, Kackertstr. 15, 52072 Aachen (Germany)

    2012-06-15

    The development of high-temperature electrochemical devices such as solid oxide fuel cells, oxygen, and hydrogen separators and gas reformers poses a great challenge in brazing technology of metal/ceramic joints. To maintain the integrity of such equipment, the resulting seals have to be stable and hermetic during continuous and cyclic high temperature operation. As a solution for joining metal and ceramic materials, reactive air brazing has gained increasing interest in recent years. This paper compares joints brazed by different filler alloys: pure Ag, AgCu, and AgAl in three different aspects: contour accuracy, room temperature delamination resistance, and corresponding microstructures of the as-brazed and fractured brazed joints. Discussion focuses on fracture mechanism and associated delamination resistance. AgAl brazed joints exhibit the most promising mechanical properties and contour accuracy. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Improving accuracy of genomic prediction in Brangus cattle by adding animals with imputed low-density SNP genotypes.

    Science.gov (United States)

    Lopes, F B; Wu, X-L; Li, H; Xu, J; Perkins, T; Genho, J; Ferretti, R; Tait, R G; Bauck, S; Rosa, G J M

    2018-02-01

    Reliable genomic prediction of breeding values for quantitative traits requires the availability of sufficient number of animals with genotypes and phenotypes in the training set. As of 31 October 2016, there were 3,797 Brangus animals with genotypes and phenotypes. These Brangus animals were genotyped using different commercial SNP chips. Of them, the largest group consisted of 1,535 animals genotyped by the GGP-LDV4 SNP chip. The remaining 2,262 genotypes were imputed to the SNP content of the GGP-LDV4 chip, so that the number of animals available for training the genomic prediction models was more than doubled. The present study showed that the pooling of animals with both original or imputed 40K SNP genotypes substantially increased genomic prediction accuracies on the ten traits. By supplementing imputed genotypes, the relative gains in genomic prediction accuracies on estimated breeding values (EBV) were from 12.60% to 31.27%, and the relative gain in genomic prediction accuracies on de-regressed EBV was slightly small (i.e. 0.87%-18.75%). The present study also compared the performance of five genomic prediction models and two cross-validation methods. The five genomic models predicted EBV and de-regressed EBV of the ten traits similarly well. Of the two cross-validation methods, leave-one-out cross-validation maximized the number of animals at the stage of training for genomic prediction. Genomic prediction accuracy (GPA) on the ten quantitative traits was validated in 1,106 newly genotyped Brangus animals based on the SNP effects estimated in the previous set of 3,797 Brangus animals, and they were slightly lower than GPA in the original data. The present study was the first to leverage currently available genotype and phenotype resources in order to harness genomic prediction in Brangus beef cattle. © 2018 Blackwell Verlag GmbH.

  4. PAIR Comparison between Two Within-Group Conditions of Resting-State fMRI Improves Classification Accuracy

    Science.gov (United States)

    Zhou, Zhen; Wang, Jian-Bao; Zang, Yu-Feng; Pan, Gang

    2018-01-01

    Classification approaches have been increasingly applied to differentiate patients and normal controls using resting-state functional magnetic resonance imaging data (RS-fMRI). Although most previous classification studies have reported promising accuracy within individual datasets, achieving high levels of accuracy with multiple datasets remains challenging for two main reasons: high dimensionality, and high variability across subjects. We used two independent RS-fMRI datasets (n = 31, 46, respectively) both with eyes closed (EC) and eyes open (EO) conditions. For each dataset, we first reduced the number of features to a small number of brain regions with paired t-tests, using the amplitude of low frequency fluctuation (ALFF) as a metric. Second, we employed a new method for feature extraction, named the PAIR method, examining EC and EO as paired conditions rather than independent conditions. Specifically, for each dataset, we obtained EC minus EO (EC—EO) maps of ALFF from half of subjects (n = 15 for dataset-1, n = 23 for dataset-2) and obtained EO—EC maps from the other half (n = 16 for dataset-1, n = 23 for dataset-2). A support vector machine (SVM) method was used for classification of EC RS-fMRI mapping and EO mapping. The mean classification accuracy of the PAIR method was 91.40% for dataset-1, and 92.75% for dataset-2 in the conventional frequency band of 0.01–0.08 Hz. For cross-dataset validation, we applied the classifier from dataset-1 directly to dataset-2, and vice versa. The mean accuracy of cross-dataset validation was 94.93% for dataset-1 to dataset-2 and 90.32% for dataset-2 to dataset-1 in the 0.01–0.08 Hz range. For the UNPAIR method, classification accuracy was substantially lower (mean 69.89% for dataset-1 and 82.97% for dataset-2), and was much lower for cross-dataset validation (64.69% for dataset-1 to dataset-2 and 64.98% for dataset-2 to dataset-1) in the 0.01–0.08 Hz range. In conclusion, for within-group design studies (e

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