Accuracy and precision of polyurethane dental arch models fabricated using a three-dimensional subtractive rapid prototyping method with an intraoral scanning technique.

PubMed

Kim, Jae-Hong; Kim, Ki-Baek; Kim, Woong-Chul; Kim, Ji-Hwan; Kim, Hae-Young

2014-03-01

This study aimed to evaluate the accuracy and precision of polyurethane (PUT) dental arch models fabricated using a three-dimensional (3D) subtractive rapid prototyping (RP) method with an intraoral scanning technique by comparing linear measurements obtained from PUT models and conventional plaster models. Ten plaster models were duplicated using a selected standard master model and conventional impression, and 10 PUT models were duplicated using the 3D subtractive RP technique with an oral scanner. Six linear measurements were evaluated in terms of x, y, and z-axes using a non-contact white light scanner. Accuracy was assessed using mean differences between two measurements, and precision was examined using four quantitative methods and the Bland-Altman graphical method. Repeatability was evaluated in terms of intra-examiner variability, and reproducibility was assessed in terms of inter-examiner and inter-method variability. The mean difference between plaster models and PUT models ranged from 0.07 mm to 0.33 mm. Relative measurement errors ranged from 2.2% to 7.6% and intraclass correlation coefficients ranged from 0.93 to 0.96, when comparing plaster models and PUT models. The Bland-Altman plot showed good agreement. The accuracy and precision of PUT dental models for evaluating the performance of oral scanner and subtractive RP technology was acceptable. Because of the recent improvements in block material and computerized numeric control milling machines, the subtractive RP method may be a good choice for dental arch models.

Evaluating the Discriminant Accuracy of a Grammatical Measure With Spanish-Speaking Children

PubMed Central

Gutiérrez-Clellen, Vera F.; Restrepo, M. Adelaida; Simón-Cereijido, Gabriela

2012-01-01

Purpose The purpose of this study was to evaluate the discriminant accuracy of a grammatical measure for the identification of language impairment in Latino Spanish-speaking children. The authors hypothesized that if exposure to and use of English as a second language have an effect on the first language, bilingual children might exhibit lower rates of grammatical accuracy than their peers and be more likely to be misclassified. Method Eighty children with typical language development and 80 with language impairment were sampled from 4 different geographical regions and compared using linear discriminant function analysis. Results Results indicated fair-to-good sensitivity from 4;0 to 5;1 years, good sensitivity from 5;2 to 5;11 years, and poor sensitivity above age 6 years. The discriminant functions derived from the exploratory studies were able to predict group membership in confirmatory analyses with fair-to-excellent sensitivity up to age 6 years. Children who were bilingual did not show lower scores and were not more likely to be misclassified compared with their Spanish-only peers. Conclusions The measure seems to be appropriate for identifying language impairment in either Spanish-dominant or Spanish-only speakers between 4 and 6 years of age. However, for older children, supplemental testing is necessary. PMID:17197491

Diagnostic accuracy for major depression in multiple sclerosis using self-report questionnaires.

PubMed

Fischer, Anja; Fischer, Marcus; Nicholls, Robert A; Lau, Stephanie; Poettgen, Jana; Patas, Kostas; Heesen, Christoph; Gold, Stefan M

2015-09-01

Multiple sclerosis and major depressive disorder frequently co-occur but depression often remains undiagnosed in this population. Self-rated depression questionnaires are a good option where clinician-based standardized diagnostics are not feasible. However, there is a paucity of data on diagnostic accuracy of self-report measures for depression in multiple sclerosis (MS). Moreover, head-to-head comparisons of common questionnaires are largely lacking. This could be particularly relevant for high-risk patients with depressive symptoms. Here, we compare the diagnostic accuracy of the Beck Depression Inventory (BDI) and 30-item version of the Inventory of Depressive Symptomatology Self-Rated (IDS-SR30) for major depressive disorder (MSS) against diagnosis by a structured clinical interview. Patients reporting depressive symptoms completed the BDI, the IDS-SR30 and underwent diagnostic assessment (Mini International Neuropsychiatric Interview, M.I.N.I.). Receiver-Operating Characteristic analyses were performed, providing error estimates and false-positive/negative rates of suggested thresholds. Data from n = 31 MS patients were available. BDI and IDS-SR30 total score were significantly correlated (r = 0.82). The IDS-SR30total score, cognitive subscore, and BDI showed excellent to good accuracy (area under the curve (AUC) 0.86, 0.91, and 0.85, respectively). Both the IDS-SR30 and the BDI are useful to quantify depressive symptoms showing good sensitivity and specificity. The IDS-SR30 cognitive subscale may be useful as a screening tool and to quantify affective/cognitive depressive symptomatology.

Abbreviation of the Follow-Up NIH Stroke Scale Using Factor Analysis

PubMed Central

Raza, Syed Ali; Frankel, Michael R.; Rangaraju, Srikant

2017-01-01

Background The NIH Stroke Scale (NIHSS) is a 15-item measure of stroke-related neurologic deficits that, when measured at 24 h, is highly predictive of long-term functional outcome. We hypothesized that a simplified 24-h scale that incorporates the most predictive components of the NIHSS can retain prognostic accuracy and have improved interrater reliability. Methods In a post hoc analysis of the Interventional Management of Stroke-3 (IMS-3) trial, we performed principal component (PC) analysis to resolve the 24-h NIHSS into PCs. In the PCs that explained the largest proportions of variance, key variables were identified. Using these key variables, the prognostic accuracies (area under the curve [AUC]) for good outcome (3-month modified Rankin Scale [mRS] 0–2) and poor outcome (mRS 5–6) of various abbreviated NIHSS iterations were compared with the total 24-h NIHSS. The results were validated in the NINDS intravenous tissue plasminogen activator (NINDS-TPA) study cohort. Based on previously published data, interrater reliability of the abbreviated 24-h NIHSS (aNIHSS) was compared to the total 24-h NIHSS. Results In 545 IMS-3 participants, 2 PCs explained 60.8% of variance in the 24-h NIHSS. The key variables in PC1 included neglect, arm and leg weakness; while PC2 included level-of-consciousness (LOC) questions, LOC commands, and aphasia. A 3-variable aNIHSS (aphasia, neglect, arm weakness) retained excellent prognostic accuracy for good outcome (AUC = 0.90) as compared to the total 24-h NIHSS (AUC = 0.91), and it was more predictive (p < 0.001) than the baseline NIHSS (AUC = 0.73). The prognostic accuracy of the aNIHSS for good outcome was validated in the NINDS-TPA trial cohort (aNIHSS: AUC = 0.89 vs. total 24-h NIHSS: 0.92). An aNIHSS >9 predicted very poor outcomes (mRS 0–2: 0%, mRS 4–6: 98.5%). The estimated interrater reliability of the aNIHSS was higher than that of the total 24-h NIHSS across 6 published datasets (mean weighted kappa 0.80 vs. 0.73, p < 0.001). Conclusions At 24 h following ischemic stroke, aphasia, neglect, and arm weakness are the most prognostically relevant neurologic findings. The aNIHSS appears to have excellent prognostic accuracy with higher reliability and may be clinically useful. PMID:28968607

Properties of young massive clusters obtained with different massive-star evolutionary models

NASA Astrophysics Data System (ADS)

Wofford, Aida; Charlot, Stéphane

We undertake a comprehensive comparative test of seven widely-used spectral synthesis models using multi-band HST photometry of a sample of eight YMCs in two galaxies. We provide a first quantitative estimate of the accuracies and uncertainties of new models, show the good progress of models in fitting high-quality observations, and highlight the need of further comprehensive comparative tests.

Diagnostic performance of a Lattice Boltzmann-based method for CT-based fractional flow reserve.

PubMed

Giannopoulos, Andreas A; Tang, Anji; Ge, Yin; Cheezum, Michael K; Steigner, Michael L; Fujimoto, Shinichiro; Kumamaru, Kanako K; Chiappino, Dante; Della Latta, Daniele; Berti, Sergio; Chiappino, Sara; Rybicki, Frank J; Melchionna, Simone; Mitsouras, Dimitrios

2018-02-20

Fractional flow reserve (FFR) estimated from coronary computed tomography angiography (CT-FFR) offers non-invasive detection of lesion-specific ischaemia. We aimed to develop and validate a fast CT-FFR algorithm utilising the Lattice Boltzmann method for blood flow simulation (LBM CT-FFR). Sixty-four patients with clinically indicated CTA and invasive FFR measurement from three institutions were retrospectively analysed. CT-FFR was performed using an onsite tool interfacing with a commercial Lattice Boltzmann fluid dynamics cloud-based platform. Diagnostic accuracy of LBM CT-FFR ≤0.8 and percent diameter stenosis >50% by CTA to detect invasive FFR ≤0.8 were compared using area under the receiver operating characteristic curve (AUC). Sixty patients successfully underwent LBM CT-FFR analysis; 29 of 73 lesions in 69 vessels had invasive FFR ≤0.8. Total time to perform LBM CT-FFR was 40±10 min. Compared to invasive FFR, LBM CT-FFR had good correlation (r=0.64), small bias (0.009) and good limits of agreement (-0.223 to 0.206). The AUC of LBM CT-FFR (AUC=0.894, 95% confidence interval [CI]: 0.792-0.996) was significantly higher than CTA (AUC=0.685, 95% CI: 0.576-0.794) to detect FFR ≤0.8 (p=0.0021). Per-lesion specificity, sensitivity, and accuracy of LBM CT-FFR were 97.7%, 79.3%, and 90.4%, respectively. LBM CT-FFR has very good diagnostic accuracy to detect lesion-specific ischaemia (FFR ≤0.8) and can be performed in less than one hour.

Method of preliminary localization of the iris in biometric access control systems

NASA Astrophysics Data System (ADS)

Minacova, N.; Petrov, I.

2015-10-01

This paper presents a method of preliminary localization of the iris, based on the stable brightness features of the iris in images of the eye. In tests on images of eyes from publicly available databases method showed good accuracy and speed compared to existing methods preliminary localization.

Automated microdensitometer for digitizing astronomical plates

NASA Technical Reports Server (NTRS)

Angilello, J.; Chiang, W. H.; Elmegreen, D. M.; Segmueller, A.

1984-01-01

A precision microdensitometer was built under control of an IBM S/1 time-sharing computer system. The instrument's spatial resolution is better than 20 microns. A raster scan of an area of 10x10 sq mm (500x500 raster points) takes 255 minutes. The reproducibility is excellent and the stability is good over a period of 30 hours, which is significantly longer than the time required for most scans. The intrinsic accuracy of the instrument was tested using Kodak standard filters, and it was found to be better than 3%. A comparative accuracy was tested measuring astronomical plates of galaxies for which absolute photoelectric photometry data were available. The results showed an accuracy excellent for astronomical applications.

Fuzzy PID control algorithm based on PSO and application in BLDC motor

NASA Astrophysics Data System (ADS)

Lin, Sen; Wang, Guanglong

2017-06-01

A fuzzy PID control algorithm is studied based on improved particle swarm optimization (PSO) to perform Brushless DC (BLDC) motor control which has high accuracy, good anti-jamming capability and steady state accuracy compared with traditional PID control. The mathematical and simulation model is established for BLDC motor by simulink software, and the speed loop of the fuzzy PID controller is designed. The simulation results show that the fuzzy PID control algorithm based on PSO has higher stability, high control precision and faster dynamic response speed.

Comorbidities in head and neck cancer: agreement between self-report and chart review.

PubMed

Mukerji, Shraddha S; Duffy, Sonia A; Fowler, Karen E; Khan, Mumtaz; Ronis, David L; Terrell, Jeffrey E

2007-04-01

To determine the accuracy of self-reported comorbidities compared with medical record review and the clinical and sociodemographic characteristics associated with accuracy of self-reported comorbidities. We conducted a prospective study of 458 newly diagnosed head and neck cancer patients using self-administered questionnaire and medical chart review data. Overall and itemwise consistency between self-report and chart review was evaluated. Social, clinical, and demographic characteristics of consistent versus inconsistent responders were analyzed. Seventy-four percent of patients had at least one comorbidity. There was good overall consistency between self-report and chart review (kappa = 0.50). Compared with consistent responders, inconsistent responders were found to be older (P < 0.05), have lower sleep (P < 0.05) and physical activity scores (P < 0.05), be more depressed (P < 0.05), and have more severe comorbidities (P < 0.05). Self-report may be considered as an alternative to chart review for comorbidity assessment in head and neck cancer patients. Younger patients, those with good general health, fewer depressive symptoms, and mild comorbidities, are more likely to give responses consistent with chart review.

Accuracy and precision of polyurethane dental arch models fabricated using a three-dimensional subtractive rapid prototyping method with an intraoral scanning technique

PubMed Central

Kim, Jae-Hong; Kim, Ki-Baek; Kim, Woong-Chul; Kim, Ji-Hwan

2014-01-01

Objective This study aimed to evaluate the accuracy and precision of polyurethane (PUT) dental arch models fabricated using a three-dimensional (3D) subtractive rapid prototyping (RP) method with an intraoral scanning technique by comparing linear measurements obtained from PUT models and conventional plaster models. Methods Ten plaster models were duplicated using a selected standard master model and conventional impression, and 10 PUT models were duplicated using the 3D subtractive RP technique with an oral scanner. Six linear measurements were evaluated in terms of x, y, and z-axes using a non-contact white light scanner. Accuracy was assessed using mean differences between two measurements, and precision was examined using four quantitative methods and the Bland-Altman graphical method. Repeatability was evaluated in terms of intra-examiner variability, and reproducibility was assessed in terms of inter-examiner and inter-method variability. Results The mean difference between plaster models and PUT models ranged from 0.07 mm to 0.33 mm. Relative measurement errors ranged from 2.2% to 7.6% and intraclass correlation coefficients ranged from 0.93 to 0.96, when comparing plaster models and PUT models. The Bland-Altman plot showed good agreement. Conclusions The accuracy and precision of PUT dental models for evaluating the performance of oral scanner and subtractive RP technology was acceptable. Because of the recent improvements in block material and computerized numeric control milling machines, the subtractive RP method may be a good choice for dental arch models. PMID:24696823

Diagnostic accuracy for major depression in multiple sclerosis using self-report questionnaires

PubMed Central

Fischer, Anja; Fischer, Marcus; Nicholls, Robert A; Lau, Stephanie; Poettgen, Jana; Patas, Kostas; Heesen, Christoph; Gold, Stefan M

2015-01-01

Objective Multiple sclerosis and major depressive disorder frequently co-occur but depression often remains undiagnosed in this population. Self-rated depression questionnaires are a good option where clinician-based standardized diagnostics are not feasible. However, there is a paucity of data on diagnostic accuracy of self-report measures for depression in multiple sclerosis (MS). Moreover, head-to-head comparisons of common questionnaires are largely lacking. This could be particularly relevant for high-risk patients with depressive symptoms. Here, we compare the diagnostic accuracy of the Beck Depression Inventory (BDI) and 30-item version of the Inventory of Depressive Symptomatology Self-Rated (IDS-SR30) for major depressive disorder (MSS) against diagnosis by a structured clinical interview. Methods Patients reporting depressive symptoms completed the BDI, the IDS-SR30 and underwent diagnostic assessment (Mini International Neuropsychiatric Interview, M.I.N.I.). Receiver-Operating Characteristic analyses were performed, providing error estimates and false-positive/negative rates of suggested thresholds. Results Data from n = 31 MS patients were available. BDI and IDS-SR30 total score were significantly correlated (r = 0.82). The IDS-SR30total score, cognitive subscore, and BDI showed excellent to good accuracy (area under the curve (AUC) 0.86, 0.91, and 0.85, respectively). Conclusion Both the IDS-SR30 and the BDI are useful to quantify depressive symptoms showing good sensitivity and specificity. The IDS-SR30 cognitive subscale may be useful as a screening tool and to quantify affective/cognitive depressive symptomatology. PMID:26445703

New Equations for Calculating Principal and Fine-Structure Atomic Spectra for Single and Multi-Electron Atoms

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

Surdoval, Wayne A.; Berry, David A.; Shultz, Travis R.

A set of equations are presented for calculating atomic principal spectral lines and fine-structure energy splits for single and multi-electron atoms. Calculated results are presented and compared to the National Institute of Science and Technology database demonstrating very good accuracy. The equations do not require fitted parameters. The only experimental parameter required is the Ionization energy for the electron of interest. The equations have comparable accuracy and broader applicability than the single electron Dirac equation. Three Appendices discuss the origin of the new equations and present calculated results. New insights into the special relativistic nature of the Dirac equation andmore » its relationship to the new equations are presented.« less

New test techniques and analytical procedures for understanding the behavior of advanced propellers

NASA Technical Reports Server (NTRS)

Stefko, G. L.; Bober, L. J.; Neumann, H. E.

1983-01-01

Analytical procedures and experimental techniques were developed to improve the capability to design advanced high speed propellers. Some results from the propeller lifting line and lifting surface aerodynamic analysis codes are compared with propeller force data, probe data and laser velocimeter data. In general, the code comparisons with data indicate good qualitative agreement. A rotating propeller force balance demonstrated good accuracy and reduced test time by 50 percent. Results from three propeller flow visualization techniques are shown which illustrate some of the physical phenomena occurring on these propellers.

Application of Improved APO Algorithm in Vulnerability Assessment and Reconstruction of Microgrid

NASA Astrophysics Data System (ADS)

Xie, Jili; Ma, Hailing

2018-01-01

Artificial Physics Optimization (APO) has good global search ability and can avoid the premature convergence phenomenon in PSO algorithm, which has good stability of fast convergence and robustness. On the basis of APO of the vector model, a reactive power optimization algorithm based on improved APO algorithm is proposed for the static structure and dynamic operation characteristics of microgrid. The simulation test is carried out through the IEEE 30-bus system and the result shows that the algorithm has better efficiency and accuracy compared with other optimization algorithms.

Feature Orientation and Positional Accuracy Assessment of Digital Orthophoto and Line Map for Large Scale Mapping: the Case Study on Bahir Dar Town, Ethiopia

NASA Astrophysics Data System (ADS)

Sisay, Z. G.; Besha, T.; Gessesse, B.

2017-05-01

This study used in-situ GPS data to validate the accuracy of horizontal coordinates and orientation of linear features of orthophoto and line map for Bahir Dar city. GPS data is processed using GAMIT/GLOBK and Lieca GeoOfice (LGO) in a least square sense with a tie to local and regional GPS reference stations to predict horizontal coordinates at five checkpoints. Real-Time-Kinematic GPS measurement technique is used to collect the coordinates of road centerline to test the accuracy associated with the orientation of the photogrammetric line map. The accuracy of orthophoto was evaluated by comparing with in-situ GPS coordinates and it is in a good agreement with a root mean square error (RMSE) of 12.45 cm in x- and 13.97 cm in y-coordinates, on the other hand, 6.06 cm with 95 % confidence level - GPS coordinates from GAMIT/GLOBK. Whereas, the horizontal coordinates of the orthophoto are in agreement with in-situ GPS coordinates at an accuracy of 16.71 cm and 18.98 cm in x and y-directions respectively and 11.07 cm with 95 % confidence level - GPS data is processed by LGO and a tie to local GPS network. Similarly, the accuracy of linear feature is in a good fit with in-situ GPS measurement. The GPS coordinates of the road centerline deviates from the corresponding coordinates of line map by a mean value of 9.18 cm in x- direction and -14.96 cm in y-direction. Therefore, it can be concluded that, the accuracy of the orthophoto and line map is within the national standard of error budget ( 25 cm).

Comparing Features for Classification of MEG Responses to Motor Imagery

PubMed Central

Halme, Hanna-Leena; Parkkonen, Lauri

2016-01-01

Background Motor imagery (MI) with real-time neurofeedback could be a viable approach, e.g., in rehabilitation of cerebral stroke. Magnetoencephalography (MEG) noninvasively measures electric brain activity at high temporal resolution and is well-suited for recording oscillatory brain signals. MI is known to modulate 10- and 20-Hz oscillations in the somatomotor system. In order to provide accurate feedback to the subject, the most relevant MI-related features should be extracted from MEG data. In this study, we evaluated several MEG signal features for discriminating between left- and right-hand MI and between MI and rest. Methods MEG was measured from nine healthy participants imagining either left- or right-hand finger tapping according to visual cues. Data preprocessing, feature extraction and classification were performed offline. The evaluated MI-related features were power spectral density (PSD), Morlet wavelets, short-time Fourier transform (STFT), common spatial patterns (CSP), filter-bank common spatial patterns (FBCSP), spatio—spectral decomposition (SSD), and combined SSD+CSP, CSP+PSD, CSP+Morlet, and CSP+STFT. We also compared four classifiers applied to single trials using 5-fold cross-validation for evaluating the classification accuracy and its possible dependence on the classification algorithm. In addition, we estimated the inter-session left-vs-right accuracy for each subject. Results The SSD+CSP combination yielded the best accuracy in both left-vs-right (mean 73.7%) and MI-vs-rest (mean 81.3%) classification. CSP+Morlet yielded the best mean accuracy in inter-session left-vs-right classification (mean 69.1%). There were large inter-subject differences in classification accuracy, and the level of the 20-Hz suppression correlated significantly with the subjective MI-vs-rest accuracy. Selection of the classification algorithm had only a minor effect on the results. Conclusions We obtained good accuracy in sensor-level decoding of MI from single-trial MEG data. Feature extraction methods utilizing both the spatial and spectral profile of MI-related signals provided the best classification results, suggesting good performance of these methods in an online MEG neurofeedback system. PMID:27992574

Higher-order triangular spectral element method with optimized cubature points for seismic wavefield modeling

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

Liu, Youshan, E-mail: ysliu@mail.iggcas.ac.cn; Teng, Jiwen, E-mail: jwteng@mail.iggcas.ac.cn; Xu, Tao, E-mail: xutao@mail.iggcas.ac.cn

2017-05-01

The mass-lumped method avoids the cost of inverting the mass matrix and simultaneously maintains spatial accuracy by adopting additional interior integration points, known as cubature points. To date, such points are only known analytically in tensor domains, such as quadrilateral or hexahedral elements. Thus, the diagonal-mass-matrix spectral element method (SEM) in non-tensor domains always relies on numerically computed interpolation points or quadrature points. However, only the cubature points for degrees 1 to 6 are known, which is the reason that we have developed a p-norm-based optimization algorithm to obtain higher-order cubature points. In this way, we obtain and tabulate newmore » cubature points with all positive integration weights for degrees 7 to 9. The dispersion analysis illustrates that the dispersion relation determined from the new optimized cubature points is comparable to that of the mass and stiffness matrices obtained by exact integration. Simultaneously, the Lebesgue constant for the new optimized cubature points indicates its surprisingly good interpolation properties. As a result, such points provide both good interpolation properties and integration accuracy. The Courant–Friedrichs–Lewy (CFL) numbers are tabulated for the conventional Fekete-based triangular spectral element (TSEM), the TSEM with exact integration, and the optimized cubature-based TSEM (OTSEM). A complementary study demonstrates the spectral convergence of the OTSEM. A numerical example conducted on a half-space model demonstrates that the OTSEM improves the accuracy by approximately one order of magnitude compared to the conventional Fekete-based TSEM. In particular, the accuracy of the 7th-order OTSEM is even higher than that of the 14th-order Fekete-based TSEM. Furthermore, the OTSEM produces a result that can compete in accuracy with the quadrilateral SEM (QSEM). The high accuracy of the OTSEM is also tested with a non-flat topography model. In terms of computational efficiency, the OTSEM is more efficient than the Fekete-based TSEM, although it is slightly costlier than the QSEM when a comparable numerical accuracy is required. - Highlights: • Higher-order cubature points for degrees 7 to 9 are developed. • The effects of quadrature rule on the mass and stiffness matrices has been conducted. • The cubature points have always positive integration weights. • Freeing from the inversion of a wide bandwidth mass matrix. • The accuracy of the TSEM has been improved in about one order of magnitude.« less

Can the prevalence of high blood drug concentrations in a population be estimated by analysing oral fluid? A study of tetrahydrocannabinol and amphetamine.

PubMed

Gjerde, Hallvard; Verstraete, Alain

2010-02-25

To study several methods for estimating the prevalence of high blood concentrations of tetrahydrocannabinol and amphetamine in a population of drug users by analysing oral fluid (saliva). Five methods were compared, including simple calculation procedures dividing the drug concentrations in oral fluid by average or median oral fluid/blood (OF/B) drug concentration ratios or linear regression coefficients, and more complex Monte Carlo simulations. Populations of 311 cannabis users and 197 amphetamine users from the Rosita-2 Project were studied. The results of a feasibility study suggested that the Monte Carlo simulations might give better accuracies than simple calculations if good data on OF/B ratios is available. If using only 20 randomly selected OF/B ratios, a Monte Carlo simulation gave the best accuracy but not the best precision. Dividing by the OF/B regression coefficient gave acceptable accuracy and precision, and was therefore the best method. None of the methods gave acceptable accuracy if the prevalence of high blood drug concentrations was less than 15%. Dividing the drug concentration in oral fluid by the OF/B regression coefficient gave an acceptable estimation of high blood drug concentrations in a population, and may therefore give valuable additional information on possible drug impairment, e.g. in roadside surveys of drugs and driving. If good data on the distribution of OF/B ratios are available, a Monte Carlo simulation may give better accuracy. 2009 Elsevier Ireland Ltd. All rights reserved.

Emotion Recognition from Congruent and Incongruent Emotional Expressions and Situational Cues in Children with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Tell, Dina; Davidson, Denise

2015-01-01

In this research, the emotion recognition abilities of children with autism spectrum disorder and typically developing children were compared. When facial expressions and situational cues of emotion were congruent, accuracy in recognizing emotions was good for both children with autism spectrum disorder and typically developing children. When…

A comparative evaluation of the analytical performances of Capillarys 2 Flex Piercing, Tosoh HLC-723 G8, Premier Hb9210, and Roche Cobas c501 Tina-quant Gen 2 analyzers for HbA1c determination.

PubMed

Wu, Xiaobin; Chao, Yan; Wan, Zemin; Wang, Yunxiu; Ma, Yan; Ke, Peifeng; Wu, Xinzhong; Xu, Jianhua; Zhuang, Junhua; Huang, Xianzhang

2016-10-15

Haemoglobin A 1c (HbA 1c ) is widely used in the management of diabetes. Therefore, the reliability and comparability among different analytical methods for its detection have become very important. A comparative evaluation of the analytical performances (precision, linearity, accuracy, method comparison, and interferences including bilirubin, triglyceride, cholesterol, labile HbA 1c (LA 1c ), vitamin C, aspirin, fetal haemoglobin (HbF), and haemoglobin E (Hb E)) were performed on Capillarys 2 Flex Piercing (Capillarys 2FP) (Sebia, France), Tosoh HLC-723 G8 (Tosoh G8) (Tosoh, Japan), Premier Hb9210 (Trinity Biotech, Ireland) and Roche Cobas c501 (Roche c501) (Roche Diagnostics, Germany). A good precision was shown at both low and high HbA 1c levels on all four systems, with all individual CVs below 2% (IFCC units) or 1.5% (NGSP units). Linearity analysis for each analyzer had achieved a good correlation coefficient (R 2 > 0.99) over the entire range tested. The analytical bias of the four systems against the IFCC targets was less than ± 6% (NGSP units), indicating a good accuracy. Method comparison showed a great correlation and agreement between methods. Very high levels of triglycerides and cholesterol (≥ 15.28 and ≥ 8.72 mmol/L, respectively) led to falsely low HbA 1c concentrations on Roche c501. Elevated HbF induced false HbA 1c detection on Capillarys 2FP (> 10%), Tosoh G8 (> 30%), Premier Hb9210 (> 15%), and Roche c501 (> 5%). On Tosoh G8, HbE induced an extra peak on chromatogram, and significantly lower results were reported. The four HbA 1c methods commonly used with commercial analyzers showed a good reliability and comparability, although some interference may falsely alter the result.

Diagnostic accuracy of language sample measures with Persian-speaking preschool children.

PubMed

Kazemi, Yalda; Klee, Thomas; Stringer, Helen

2015-04-01

This study examined the diagnostic accuracy of selected language sample measures (LSMs) with Persian-speaking children. A pre-accuracy study followed by phase I and II studies are reported. Twenty-four Persian-speaking children, aged 42 to 54 months, with primary language impairment (PLI) were compared to 27 age-matched children without PLI on a set of measures derived from play-based, conversational language samples. Results showed that correlations between age and LSMs were not statistically significant in either group of children. However, a majority of LSMs differentiated children with and without PLI at the group level (phase I), while three of the measures exhibited good diagnostic accuracy at the level of the individual (phase II). We conclude that general LSMs are promising for distinguishing between children with and without PLI. Persian-specific measures are mainly helpful in identifying children without language impairment while their ability to identify children with PLI is poor.

Evaluation of diagnostic accuracy in detecting ordered symptom statuses without a gold standard

PubMed Central

Wang, Zheyu; Zhou, Xiao-Hua; Wang, Miqu

2011-01-01

Our research is motivated by 2 methodological problems in assessing diagnostic accuracy of traditional Chinese medicine (TCM) doctors in detecting a particular symptom whose true status has an ordinal scale and is unknown—imperfect gold standard bias and ordinal scale symptom status. In this paper, we proposed a nonparametric maximum likelihood method for estimating and comparing the accuracy of different doctors in detecting a particular symptom without a gold standard when the true symptom status had an ordered multiple class. In addition, we extended the concept of the area under the receiver operating characteristic curve to a hyper-dimensional overall accuracy for diagnostic accuracy and alternative graphs for displaying a visual result. The simulation studies showed that the proposed method had good performance in terms of bias and mean squared error. Finally, we applied our method to our motivating example on assessing the diagnostic abilities of 5 TCM doctors in detecting symptoms related to Chills disease. PMID:21209155

Comparison of Laser Scanning Diagnostic Devices for Early Glaucoma Detection.

PubMed

Schulze, Andreas; Lamparter, Julia; Pfeiffer, Norbert; Berisha, Fatmire; Schmidtmann, Irene; Hoffmann, Esther M

2015-08-01

To compare the diagnostic accuracy and to evaluate the correlation of optic nerve head and retinal nerve fiber layer thickness values between Fourier-Domain optical coherence tomography (FD-OCT), confocal scanning laser ophthalmoscopy (CSLO), and scanning laser polarimetry (SLP) for early glaucoma detection. Ninety-three patients with early open-angle glaucoma, 58 patients with ocular hypertension, and 60 healthy control subjects were included in this observational, cross-sectional study. All study participants underwent FD-OCT (RTVue-100), CSLO (HRT3), and SLP (GDx VCC) imaging of the optic nerve head and the retinal nerve fiber layer. Area under the receiver operating characteristic curves (AUROC) and Bland-Altman analysis were performed. The parameters with the highest diagnostic accuracy were found for FD-OCT cup-to-disc ratio (AUROC=0.841), for SLP NFI (AUROC=0.835), and for CSLO cup-to-disc ratio (AUROC=0.789). Diagnostic accuracy of the best CSLO and SLP parameter was similar (P=0.259). There was a small statistically significant difference between the best CSLO and FD-OCT parameters for differentiating between glaucoma and healthy eyes (P=0.047). FD-OCT and SLP have a similarly good diagnostic ability to distinguish between early glaucoma and healthy subjects. The diagnostic accuracy of CSLO was comparable with SLP and marginally lower compared with FD-OCT.

Quantitative comparison of OSEM and penalized likelihood image reconstruction using relative difference penalties for clinical PET

NASA Astrophysics Data System (ADS)

Ahn, Sangtae; Ross, Steven G.; Asma, Evren; Miao, Jun; Jin, Xiao; Cheng, Lishui; Wollenweber, Scott D.; Manjeshwar, Ravindra M.

2015-08-01

Ordered subset expectation maximization (OSEM) is the most widely used algorithm for clinical PET image reconstruction. OSEM is usually stopped early and post-filtered to control image noise and does not necessarily achieve optimal quantitation accuracy. As an alternative to OSEM, we have recently implemented a penalized likelihood (PL) image reconstruction algorithm for clinical PET using the relative difference penalty with the aim of improving quantitation accuracy without compromising visual image quality. Preliminary clinical studies have demonstrated visual image quality including lesion conspicuity in images reconstructed by the PL algorithm is better than or at least as good as that in OSEM images. In this paper we evaluate lesion quantitation accuracy of the PL algorithm with the relative difference penalty compared to OSEM by using various data sets including phantom data acquired with an anthropomorphic torso phantom, an extended oval phantom and the NEMA image quality phantom; clinical data; and hybrid clinical data generated by adding simulated lesion data to clinical data. We focus on mean standardized uptake values and compare them for PL and OSEM using both time-of-flight (TOF) and non-TOF data. The results demonstrate improvements of PL in lesion quantitation accuracy compared to OSEM with a particular improvement in cold background regions such as lungs.

An Improved P-Phase Arrival Picking Method S/L-K-A with an Application to the Yongshaba Mine in China

NASA Astrophysics Data System (ADS)

Shang, Xueyi; Li, Xibing; Morales-Esteban, A.; Dong, Longjun

2018-02-01

Automatic microseismic P-phase arrival picking is paramount for microseismic event identification, event location and source mechanism analysis. The commonly used STA/LTA picker, PAI-K picker, AIC picker and three proposed pickers have been applied to determine the P-phase arrivals of 580 microseismic signals (the sampling frequency is 6000 Hz). These have been obtained from the Institute of Mine Seismology (IMS) acquisition system of the Yongshaba mine in China. Then, the six above-mentioned pickers have been compared in their picking accuracy, typical waveforms, signal-to-noise ratio (SNR) adaptabilities and quantitative evaluation. The results have shown that: (1) the triggered STA/LTA picker has a good picking stability but a low picking accuracy. While the PAI-K and the AIC pickers have a higher picking accuracy but a poorer picking stability compared with the triggered STA/LTA picker. Moreover, the AIC picker usually has a better picking result than the PAI-K picker; (2) the S/L-K-A picker significantly improves the STA/LTA, the PAI-K and the S/L + PAI-K pickers. Moreover, it obviously improves the AIC and the S/L + AIC pickers' large picking error (> 30 ms) signals; (3) the picking error ratios of the S/L-K-A picker within 10, 20 and 30 ms achieve 92.76, 95.86 and 97.41%, respectively. The S/L-K-A picker enhances the picking adaptability to different waveforms and SNRs. In conclusion, the S/L-K-A picker provides a new method for automatic microseismic P-phase arrival picking with a high accuracy and a good stability.

SU-F-T-479: Estimation of the Accuracy in Respiratory-Gated Radiotherapy

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

Kurosawa, T; Miyakawa, S; Sato, M

Purpose: Irregular respiratory patterns affects dose outputs in respiratorygated radiotherapy and there is no commercially available quality assurance (QA) system for it. We designed and developed a patient specific QA system for respiratory-gated radiotherapy to estimate irradiated output. Methods: Our in-house QA system for gating was composed of a personal computer with the USB-FSIO electronic circuit connecting to the linear accelerator (ONCOR-K, Toshiba Medical Systems). The linac implements a respiratory gating system (AZ-733V, Anzai Medical). During the beam was on, 4.2 V square-wave pulses were continually sent to the system. Our system can receive and count the pulses. At first,more » our system and an oscilloscope were compared to check the performance of our system. Next, basic estimation models were generated when ionization-chamber measurements were performed in gating using regular sinusoidal wave patterns (2.0, 2.5, 4.0, 8.0, 15 sec/cycle). During gated irradiation with the regular patterns, the number of the pulses per one gating window was measured using our system. Correlation between the number of the pulses per one gating and dose per the gating window were assessed to generate the estimation model. Finally, two irregular respiratory patterns were created and the accuracy of the estimation was evaluated. Results: Compared to the oscilloscope, our system worked similarly. The basic models were generated with the accuracy within 0.1%. The results of the gated irradiations with two irregular respiratory patterns show good agreement within 0.4% estimation accuracy. Conclusion: Our developed system shows good estimation for even irregular respiration patterns. The system would be a useful tool to verify the output for respiratory-gated radiotherapy.« less

Decay Properties of K-Vacancy States in Fe X-Fe XVII

NASA Technical Reports Server (NTRS)

Mendoza, C.; Kallman, T. R.; Bautista, M. A.; Palmeri, P.

2003-01-01

We report extensive calculations of the decay properties of fine-structure K-vacancy levels in Fe X-Fe XVII. A large set of level energies, wavelengths, radiative and Auger rates, and fluorescence yields has been computed using three different standard atomic codes, namely Cowan's HFR, AUTOSTRUCTURE and the Breit-Pauli R-matrix package. This multi-code approach is used to the study the effects of core relaxation, configuration interaction and the Breit interaction, and enables the estimate of statistical accuracy ratings. The Ksigma and KLL Auger widths have been found to be nearly independent of both the outer-electron configuration and electron occupancy keeping a constant ratio of 1.53 +/- 0.06. By comparing with previous theoretical and measured wavelengths, the accuracy of the present set is determined to be within 2 m Angstrom. Also, the good agreement found between the different radiative and Auger data sets that have been computed allow us to propose with confidence an accuracy rating of 20% for the line fluorescence yields greater than 0.01. Emission and absorption spectral features are predicted finding good correlation with measurements in both laboratory and astrophysical plasmas.

Determination of Monensin in Bovine Tissues: A Bridging Study Comparing the Bioautographic Method (FSIS CLG-MON) with a Liquid Chromatography-Tandem Mass Spectrometry Method (OMA 2011.24).

PubMed

Mizinga, Kemmy M; Burnett, Thomas J; Brunelle, Sharon L; Wallace, Michael A; Coleman, Mark R

2018-05-01

The U.S. Department of Agriculture, Food Safety Inspection Service regulatory method for monensin, Chemistry Laboratory Guidebook CLG-MON, is a semiquantitative bioautographic method adopted in 1991. Official Method of AnalysisSM (OMA) 2011.24, a modern quantitative and confirmatory LC-tandem MS method, uses no chlorinated solvents and has several advantages, including ease of use, ready availability of reagents and materials, shorter run-time, and higher throughput than CLG-MON. Therefore, a bridging study was conducted to support the replacement of method CLG-MON with OMA 2011.24 for regulatory use. Using fortified bovine tissue samples, CLG-MON yielded accuracies of 80-120% in 44 of the 56 samples tested (one sample had no result, six samples had accuracies of >120%, and five samples had accuracies of 40-160%), but the semiquantitative nature of CLG-MON prevented assessment of precision, whereas OMA 2011.24 had accuracies of 88-110% and RSDr of 0.00-15.6%. Incurred residue results corroborated these results, demonstrating improved accuracy (83.3-114%) and good precision (RSDr of 2.6-20.5%) for OMA 2011.24 compared with CLG-MON (accuracy generally within 80-150%, with exceptions). Furthermore, χ2 analysis revealed no statistically significant difference between the two methods. Thus, the microbiological activity of monensin correlated with the determination of monensin A in bovine tissues, and OMA 2011.24 provided improved accuracy and precision over CLG-MON.

Comparison of Feature Selection Techniques in Machine Learning for Anatomical Brain MRI in Dementia.

PubMed

Tohka, Jussi; Moradi, Elaheh; Huttunen, Heikki

2016-07-01

We present a comparative split-half resampling analysis of various data driven feature selection and classification methods for the whole brain voxel-based classification analysis of anatomical magnetic resonance images. We compared support vector machines (SVMs), with or without filter based feature selection, several embedded feature selection methods and stability selection. While comparisons of the accuracy of various classification methods have been reported previously, the variability of the out-of-training sample classification accuracy and the set of selected features due to independent training and test sets have not been previously addressed in a brain imaging context. We studied two classification problems: 1) Alzheimer's disease (AD) vs. normal control (NC) and 2) mild cognitive impairment (MCI) vs. NC classification. In AD vs. NC classification, the variability in the test accuracy due to the subject sample did not vary between different methods and exceeded the variability due to different classifiers. In MCI vs. NC classification, particularly with a large training set, embedded feature selection methods outperformed SVM-based ones with the difference in the test accuracy exceeding the test accuracy variability due to the subject sample. The filter and embedded methods produced divergent feature patterns for MCI vs. NC classification that suggests the utility of the embedded feature selection for this problem when linked with the good generalization performance. The stability of the feature sets was strongly correlated with the number of features selected, weakly correlated with the stability of classification accuracy, and uncorrelated with the average classification accuracy.

Comparative Study on the Different Testing Techniques in Tree Classification for Detecting the Learning Motivation

NASA Astrophysics Data System (ADS)

Juliane, C.; Arman, A. A.; Sastramihardja, H. S.; Supriana, I.

2017-03-01

Having motivation to learn is a successful requirement in a learning process, and needs to be maintained properly. This study aims to measure learning motivation, especially in the process of electronic learning (e-learning). Here, data mining approach was chosen as a research method. For the testing process, the accuracy comparative study on the different testing techniques was conducted, involving Cross Validation and Percentage Split. The best accuracy was generated by J48 algorithm with a percentage split technique reaching at 92.19 %. This study provided an overview on how to detect the presence of learning motivation in the context of e-learning. It is expected to be good contribution for education, and to warn the teachers for whom they have to provide motivation.

Follow-up of intracranial aneurysms treated with stent-assisted coiling: Comparison of contrast-enhanced MRA, time-of-flight MRA, and digital subtraction angiography.

PubMed

Marciano, David; Soize, Sébastien; Metaxas, Georgios; Portefaix, Christophe; Pierot, Laurent

2017-02-01

Data about non-invasive follow-up of aneurysm after stent-assisted coiling is scarce. We aimed to compare time-of-flight (TOF) magnetic resonance angiography (MRA) (3D-TOF-MRA) and contrast-enhanced MRA (CE-MRA) at 3-Tesla, with digital subtraction angiography (DSA) for evaluating aneurysm occlusion and parent artery patency after stent-assisted coiling. In this retrospective single-center study, patients were included if they had an intracranial aneurysm treated by stent-assisted coiling between March 2008 and June 2015, followed with both MRA sequences (3D-TOF-MRA and CE-MRA) at 3-Tesla and DSA, performed in an interval<48hours. Thirty-five aneurysms were included. Regarding aneurysm occlusion evaluation, agreement with DSA was better for CE-MRA (K=0.53) than 3D-TOF-MRA (K=0.28). Diagnostic accuracies for aneurysm remnant depiction were similar for 3D-TOF-MRA and CE-MRA (P=1). Both 3D-TOF-MRA (K=0.05) and CE-MRA (K=-0.04) were unable to detect pathological vessel compared to DSA, without difference in accuracy (P=0.68). For parent artery occlusion detection, agreement with DSA was substantial for 3D-TOF-MRA (K=0.64) and moderate for CE-MRA (K=0.45), with similar good diagnostic accuracies (P=1). After stent-assisted coiling treatment, 3D-TOF-MRA and CE-MRA demonstrated good accuracy to detect aneurysm remnant (but tended to overestimation). Although CE-MRA agreement with DSA was better, there was no statistical difference between 3D-TOF-MRA and CE-MRA accuracies. Both MRAs were unable to provide a precise evaluation of in-stent status but could detect parent vessel occlusion. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Attribute Weighting Based K-Nearest Neighbor Using Gain Ratio

NASA Astrophysics Data System (ADS)

Nababan, A. A.; Sitompul, O. S.; Tulus

2018-04-01

K- Nearest Neighbor (KNN) is a good classifier, but from several studies, the result performance accuracy of KNN still lower than other methods. One of the causes of the low accuracy produced, because each attribute has the same effect on the classification process, while some less relevant characteristics lead to miss-classification of the class assignment for new data. In this research, we proposed Attribute Weighting Based K-Nearest Neighbor Using Gain Ratio as a parameter to see the correlation between each attribute in the data and the Gain Ratio also will be used as the basis for weighting each attribute of the dataset. The accuracy of results is compared to the accuracy acquired from the original KNN method using 10-fold Cross-Validation with several datasets from the UCI Machine Learning repository and KEEL-Dataset Repository, such as abalone, glass identification, haberman, hayes-roth and water quality status. Based on the result of the test, the proposed method was able to increase the classification accuracy of KNN, where the highest difference of accuracy obtained hayes-roth dataset is worth 12.73%, and the lowest difference of accuracy obtained in the abalone dataset of 0.07%. The average result of the accuracy of all dataset increases the accuracy by 5.33%.

40 CFR 92.127 - Emission measurement accuracy.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Emission measurement accuracy. (a) Good engineering practice dictates that exhaust emission sample analyzer... resolution read-out systems such as computers, data loggers, etc., can provide sufficient accuracy and...

40 CFR 92.127 - Emission measurement accuracy.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Emission measurement accuracy. (a) Good engineering practice dictates that exhaust emission sample analyzer... resolution read-out systems such as computers, data loggers, etc., can provide sufficient accuracy and...

40 CFR 92.127 - Emission measurement accuracy.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Emission measurement accuracy. (a) Good engineering practice dictates that exhaust emission sample analyzer... resolution read-out systems such as computers, data loggers, etc., can provide sufficient accuracy and...

40 CFR 92.127 - Emission measurement accuracy.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Emission measurement accuracy. (a) Good engineering practice dictates that exhaust emission sample analyzer... resolution read-out systems such as computers, data loggers, etc., can provide sufficient accuracy and...

40 CFR 92.127 - Emission measurement accuracy.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Emission measurement accuracy. (a) Good engineering practice dictates that exhaust emission sample analyzer... resolution read-out systems such as computers, data loggers, etc., can provide sufficient accuracy and...

40 CFR 89.310 - Analyzer accuracy and specifications.

Code of Federal Regulations, 2010 CFR

2010-07-01

... to § 89.323. (c) Emission measurement accuracy—Bag sampling. (1) Good engineering practice dictates... generally not be used. (2) Some high resolution read-out systems, such as computers, data loggers, and so..., using good engineering judgement, below 15 percent of full scale are made to ensure the accuracy of the...

40 CFR 89.310 - Analyzer accuracy and specifications.

Code of Federal Regulations, 2011 CFR

2011-07-01

... to § 89.323. (c) Emission measurement accuracy—Bag sampling. (1) Good engineering practice dictates... generally not be used. (2) Some high resolution read-out systems, such as computers, data loggers, and so..., using good engineering judgement, below 15 percent of full scale are made to ensure the accuracy of the...

40 CFR 89.310 - Analyzer accuracy and specifications.

Code of Federal Regulations, 2013 CFR

2013-07-01

... to § 89.323. (c) Emission measurement accuracy—Bag sampling. (1) Good engineering practice dictates... generally not be used. (2) Some high resolution read-out systems, such as computers, data loggers, and so..., using good engineering judgement, below 15 percent of full scale are made to ensure the accuracy of the...

40 CFR 89.310 - Analyzer accuracy and specifications.

Code of Federal Regulations, 2012 CFR

2012-07-01

... to § 89.323. (c) Emission measurement accuracy—Bag sampling. (1) Good engineering practice dictates... generally not be used. (2) Some high resolution read-out systems, such as computers, data loggers, and so..., using good engineering judgement, below 15 percent of full scale are made to ensure the accuracy of the...

40 CFR 89.310 - Analyzer accuracy and specifications.

Code of Federal Regulations, 2014 CFR

2014-07-01

... to § 89.323. (c) Emission measurement accuracy—Bag sampling. (1) Good engineering practice dictates... generally not be used. (2) Some high resolution read-out systems, such as computers, data loggers, and so..., using good engineering judgement, below 15 percent of full scale are made to ensure the accuracy of the...

Diagnostic Accuracy and Clinical Implications of Translabial Ultrasound for the Assessment of Levator Ani Defects and Levator Ani Biometry in Women With Pelvic Organ Prolapse: A Systematic Review.

PubMed

Notten, Kim J B; Vergeldt, Tineke F M; van Kuijk, Sander M J; Weemhoff, Mirjam; Roovers, Jan-Paul W R

The aim of this study was to assess the diagnostic accuracy and clinical implications of translabial 3-dimensional (3D) ultrasound for the assessment of levator ani defects and biometry in women with pelvic organ prolapse (POP). We performed a systematic literature search through computerized databases including MEDLINE (via PubMed), EMBASE (via OvidSP), and the Cochrane Library using both medical subject headings and text terms from January 1, 2003, to December 25, 2015.We included articles that reported on POP status and diagnostic accuracy measurements with translabial 3D ultrasound or transperineal ultrasound for the detection of levator ani defects or for measuring pelvic floor biometry, that is, levator ani hiatus, or reported on the clinical relevance of using translabial 3D ultrasound for levator ani defects or measuring pelvic floor biometry in women with POP. Thirty-one articles were selected in accordance with parts of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines that can be applied to studies of diagnostic accuracy. Twenty-two articles (71%) are coauthored by 1 expert in this field. Detecting levator ani defects with translabial 3D ultrasound compared with magnetic resonance imaging showed a moderate to good agreement, whereas measuring hiatal biometry on translabial 3D ultrasound compared with magnetic resonance imaging showed a moderate to very good agreement.The interobserver agreement for diagnosing levator ani defects and measuring the levator hiatal area showed a moderate to very good agreement. Furthermore, levator ani defects increase the risk of cystocele and uterine prolapse, and levator ani defects are associated with recurrent POP.Finally, a larger hiatus was associated with POP and recurrent POP. Translabial 3D ultrasound is reproducible for diagnosing levator ani defects and ballooning hiatus. Both levator ani defects and a larger hiatal area are, in a selected population of patients with pelvic floor dysfunction, associated with POP and recurrent POP. More research is needed concerning external validation because most data in this article are coauthored by 1 expert in this field.

Golden Ratio Versus Pi as Random Sequence Sources for Monte Carlo Integration

NASA Technical Reports Server (NTRS)

Sen, S. K.; Agarwal, Ravi P.; Shaykhian, Gholam Ali

2007-01-01

We discuss here the relative merits of these numbers as possible random sequence sources. The quality of these sequences is not judged directly based on the outcome of all known tests for the randomness of a sequence. Instead, it is determined implicitly by the accuracy of the Monte Carlo integration in a statistical sense. Since our main motive of using a random sequence is to solve real world problems, it is more desirable if we compare the quality of the sequences based on their performances for these problems in terms of quality/accuracy of the output. We also compare these sources against those generated by a popular pseudo-random generator, viz., the Matlab rand and the quasi-random generator ha/ton both in terms of error and time complexity. Our study demonstrates that consecutive blocks of digits of each of these numbers produce a good random sequence source. It is observed that randomly chosen blocks of digits do not have any remarkable advantage over consecutive blocks for the accuracy of the Monte Carlo integration. Also, it reveals that pi is a better source of a random sequence than theta when the accuracy of the integration is concerned.

A ratiometric strategy -based electrochemical sensing interface for the sensitive and reliable detection of imidacloprid.

PubMed

Li, Xueyan; Kan, Xianwen

2018-04-30

In this study, a ratiometric strategy-based electrochemical sensor was developed by electropolymerization of thionine (THI) and β-cyclodextrin (β-CD) composite films on a glassy carbon electrode surface for imidacloprid (IMI) detection. THI played the role of an inner reference element to provide a built-in correction. In addition, the modified β-CD showed good selective enrichment for IMI to improve the sensitivity and anti-interference ability of the sensor. The current ratio between IMI and THI was calculated as the detected signal for IMI sensing. Compared with common single-signal sensing, the proposed ratiometric strategy showed a higher linear range and a lower limit of detection of 4.0 × 10-8-1.0 × 10-5 mol L-1 and 1.7 × 10-8 mol L-1, respectively, for IMI detection. On the other hand, the ratiometric strategy endowed the sensor with good accuracy, reproducibility, and stability. The sensor was also used for IMI determination in real samples with satisfactory results. The simple, effective, and reliable way reported in this study can be further used to prepare ratiometric strategy-based electrochemical sensors for the selective and sensitive detection of other compounds with good accuracy and stability.

Patient-specific 3D models created by 3D imaging system or bi-planar imaging coupled with Moiré-Fringe projections: a comparative study of accuracy and reliability on spinal curvatures and vertebral rotation data.

PubMed

Hocquelet, Arnaud; Cornelis, François; Jirot, Anna; Castaings, Laurent; de Sèze, Mathieu; Hauger, Olivier

2016-10-01

The aim of this study is to compare the accuracy and reliability of spinal curvatures and vertebral rotation data based on patient-specific 3D models created by 3D imaging system or by bi-planar imaging coupled with Moiré-Fringe projections. Sixty-two consecutive patients from a single institution were prospectively included. For each patient, frontal and sagittal calibrated low-dose bi-planar X-rays were performed and coupled simultaneously with an optical Moiré back surface-based technology. The 3D reconstructions of spine and pelvis were performed independently by one radiologist and one technician in radiology using two different semi-automatic methods using 3D radio-imaging system (method 1) or bi-planar imaging coupled with Moiré projections (method 2). Both methods were compared using Bland-Altman analysis, and reliability using intraclass correlation coefficient (ICC). ICC showed good to very good agreement. Between the two techniques, the maximum 95 % prediction limits was -4.9° degrees for the measurements of spinal coronal curves and less than 5° for other parameters. Inter-rater reliability was excellent for all parameters across both methods, except for axial rotation with method 2 for which ICC was fair. Method 1 was faster for reconstruction time than method 2 for both readers (13.4 vs. 20.7 min and 10.6 vs. 13.9 min; p = 0.0001). While a lower accuracy was observed for the evaluation of the axial rotation, bi-planar imaging coupled with Moiré-Fringe projections may be an accurate and reliable tool to perform 3D reconstructions of the spine and pelvis.

Accuracy of self-reported nevus and pigmentation phenotype compared with clinical assessment in a population-based study of young Australian adults.

PubMed

Cust, Anne E; Pickles, Kristen M; Goumas, Chris; Vu, Thao; Schmid, Helen; Nagore, Eduardo; Kelly, John; Aitken, Joanne F; Giles, Graham G; Hopper, John L; Jenkins, Mark A; Mann, Graham J

2015-04-01

Awareness of individual risk may encourage improved prevention and early detection of melanoma. We evaluated the accuracy of self-reported pigmentation and nevus phenotype compared with clinical assessment, and examined agreement between nevus counts from selected anatomical regions. The sample included 456 cases with invasive cutaneous melanoma diagnosed between ages 18 to 39 years and 538 controls from the population-based Australian Melanoma Family Study. Participants completed a questionnaire about their pigmentation and nevus phenotype, and attended a dermatologic skin examination. There was strong agreement between self-reported and clinical assessment of eye color [κ, = 0.78; 95% confidence interval (CI), 0.74-0.81]; and moderate agreement for hair color (κ = 0.46; 95% CI, 0.42-0.50). Agreement between self-reported skin color and spectrophotometer-derived measurements was poor (κ = 0.12; 95% CI, 0.08-0.16) to moderate (Spearman correlation rs = -0.37; 95% CI, -0.32 to -0.42). Participants tended to underestimate their nevus counts and pigmentation; men were more likely to underreport their skin color. The rs was 0.43 (95% CI, 0.38-0.49) comparing clinical total body nevus counts with self-reported nevus categories. There was good agreement between total body nevus counts and site-specific nevus counts, particularly on both arms. Young adults have suboptimal accuracy when assessing important risk characteristics including nevus numbers and pigmentation. Measuring nevus count on the arms is a good predictor of full body nevus count. These results have implications for the likely success of targeted public health programs that rely on self-assessment of these factors. ©2015 American Association for Cancer Research.

Accuracy of self-reported nevus and pigmentation phenotype compared to clinical assessment in a population-based study of young Australian adults

PubMed Central

Cust, Anne E.; Pickles, Kristen M.; Goumas, Chris; Vu, Thao; Schmid, Helen; Nagore, Eduardo; Kelly, John; Aitken, Joanne F.; Giles, Graham G.; Hopper, John L.; Jenkins, Mark A.; Mann, Graham J.

2015-01-01

Background Awareness of individual risk may encourage improved prevention and early detection of melanoma. Methods We evaluated the accuracy of self-reported pigmentation and nevus phenotype compared to clinical assessment, and examined agreement between nevus counts from selected anatomical regions. The sample included 456 cases with invasive cutaneous melanoma diagnosed between ages 18-39 years and 538 controls from the population-based Australian Melanoma Family Study. Participants completed a questionnaire regarding their pigmentation and nevus phenotype, and attended a dermatologic skin examination. Results There was strong agreement between self-reported and clinical assessment of eye color (kappa, κ, =0.78, 95% confidence interval (CI) 0.74-0.81); and moderate agreement for hair color (κ =0.46, 95% CI 0.42-0.50). Agreement between self-reported skin color and spectrophotometer-derived measurements was poor (κ =0.12, 95% CI 0.08-0.16) to moderate (Spearman correlation rs=-0.37, 95% CI -0.32- to -0.42). Participants tended to under-estimate their nevus counts and pigmentation; men were more likely to under-report their skin color. The rs was 0.43 (95% CI 0.38-0.49) comparing clinical total body nevus counts with self-reported nevus categories. There was good agreement of quartile distributions of total body nevus counts with site-specific nevus counts, particularly on both arms. Conclusions Young adults have sub-optimal accuracy when assessing important risk characteristics including nevus numbers and pigmentation. Measuring nevus count on the arms is a good predictor of full body nevus count. Impact These results have implications for the likely success of targeted public health programs that rely on self-assessment of these factors. PMID:25628333

Inertial Measures of Motion for Clinical Biomechanics: Comparative Assessment of Accuracy under Controlled Conditions - Effect of Velocity

PubMed Central

Lebel, Karina; Boissy, Patrick; Hamel, Mathieu; Duval, Christian

2013-01-01

Background Inertial measurement of motion with Attitude and Heading Reference Systems (AHRS) is emerging as an alternative to 3D motion capture systems in biomechanics. The objectives of this study are: 1) to describe the absolute and relative accuracy of multiple units of commercially available AHRS under various types of motion; and 2) to evaluate the effect of motion velocity on the accuracy of these measurements. Methods The criterion validity of accuracy was established under controlled conditions using an instrumented Gimbal table. AHRS modules were carefully attached to the center plate of the Gimbal table and put through experimental static and dynamic conditions. Static and absolute accuracy was assessed by comparing the AHRS orientation measurement to those obtained using an optical gold standard. Relative accuracy was assessed by measuring the variation in relative orientation between modules during trials. Findings Evaluated AHRS systems demonstrated good absolute static accuracy (mean error < 0.5o) and clinically acceptable absolute accuracy under condition of slow motions (mean error between 0.5o and 3.1o). In slow motions, relative accuracy varied from 2o to 7o depending on the type of AHRS and the type of rotation. Absolute and relative accuracy were significantly affected (p<0.05) by velocity during sustained motions. The extent of that effect varied across AHRS. Interpretation Absolute and relative accuracy of AHRS are affected by environmental magnetic perturbations and conditions of motions. Relative accuracy of AHRS is mostly affected by the ability of all modules to locate the same global reference coordinate system at all time. Conclusions Existing AHRS systems can be considered for use in clinical biomechanics under constrained conditions of use. While their individual capacity to track absolute motion is relatively consistent, the use of multiple AHRS modules to compute relative motion between rigid bodies needs to be optimized according to the conditions of operation. PMID:24260324

Research on Remote Sensing Geological Information Extraction Based on Object Oriented Classification

NASA Astrophysics Data System (ADS)

Gao, Hui

2018-04-01

The northern Tibet belongs to the Sub cold arid climate zone in the plateau. It is rarely visited by people. The geological working conditions are very poor. However, the stratum exposures are good and human interference is very small. Therefore, the research on the automatic classification and extraction of remote sensing geological information has typical significance and good application prospect. Based on the object-oriented classification in Northern Tibet, using the Worldview2 high-resolution remote sensing data, combined with the tectonic information and image enhancement, the lithological spectral features, shape features, spatial locations and topological relations of various geological information are excavated. By setting the threshold, based on the hierarchical classification, eight kinds of geological information were classified and extracted. Compared with the existing geological maps, the accuracy analysis shows that the overall accuracy reached 87.8561 %, indicating that the classification-oriented method is effective and feasible for this study area and provides a new idea for the automatic extraction of remote sensing geological information.

Continuous Glucose Monitoring and Trend Accuracy

PubMed Central

Gottlieb, Rebecca; Le Compte, Aaron; Chase, J. Geoffrey

2014-01-01

Continuous glucose monitoring (CGM) devices are being increasingly used to monitor glycemia in people with diabetes. One advantage with CGM is the ability to monitor the trend of sensor glucose (SG) over time. However, there are few metrics available for assessing the trend accuracy of CGM devices. The aim of this study was to develop an easy to interpret tool for assessing trend accuracy of CGM data. SG data from CGM were compared to hourly blood glucose (BG) measurements and trend accuracy was quantified using the dot product. Trend accuracy results are displayed on the Trend Compass, which depicts trend accuracy as a function of BG. A trend performance table and Trend Index (TI) metric are also proposed. The Trend Compass was tested using simulated CGM data with varying levels of error and variability, as well as real clinical CGM data. The results show that the Trend Compass is an effective tool for differentiating good trend accuracy from poor trend accuracy, independent of glycemic variability. Furthermore, the real clinical data show that the Trend Compass assesses trend accuracy independent of point bias error. Finally, the importance of assessing trend accuracy as a function of BG level is highlighted in a case example of low and falling BG data, with corresponding rising SG data. This study developed a simple to use tool for quantifying trend accuracy. The resulting trend accuracy is easily interpreted on the Trend Compass plot, and if required, performance table and TI metric. PMID:24876437

Accuracy of Monte Carlo simulations compared to in-vivo MDCT dosimetry.

PubMed

Bostani, Maryam; Mueller, Jonathon W; McMillan, Kyle; Cody, Dianna D; Cagnon, Chris H; DeMarco, John J; McNitt-Gray, Michael F

2015-02-01

The purpose of this study was to assess the accuracy of a Monte Carlo simulation-based method for estimating radiation dose from multidetector computed tomography (MDCT) by comparing simulated doses in ten patients to in-vivo dose measurements. MD Anderson Cancer Center Institutional Review Board approved the acquisition of in-vivo rectal dose measurements in a pilot study of ten patients undergoing virtual colonoscopy. The dose measurements were obtained by affixing TLD capsules to the inner lumen of rectal catheters. Voxelized patient models were generated from the MDCT images of the ten patients, and the dose to the TLD for all exposures was estimated using Monte Carlo based simulations. The Monte Carlo simulation results were compared to the in-vivo dose measurements to determine accuracy. The calculated mean percent difference between TLD measurements and Monte Carlo simulations was -4.9% with standard deviation of 8.7% and a range of -22.7% to 5.7%. The results of this study demonstrate very good agreement between simulated and measured doses in-vivo. Taken together with previous validation efforts, this work demonstrates that the Monte Carlo simulation methods can provide accurate estimates of radiation dose in patients undergoing CT examinations.

New triangular and quadrilateral plate-bending finite elements

NASA Technical Reports Server (NTRS)

Narayanaswami, R.

1974-01-01

A nonconforming plate-bending finite element of triangular shape and associated quadrilateral elements are developed. The transverse displacement is approximated within the element by a quintic polynomial. The formulation takes into account the effects of transverse shear deformation. Results of the static and dynamic analysis of a square plate, with edges simply supported or clamped, are compared with exact solutions. Good accuracy is obtained in all calculations.

A new accuracy measure based on bounded relative error for time series forecasting

PubMed Central

Twycross, Jamie; Garibaldi, Jonathan M.

2017-01-01

Many accuracy measures have been proposed in the past for time series forecasting comparisons. However, many of these measures suffer from one or more issues such as poor resistance to outliers and scale dependence. In this paper, while summarising commonly used accuracy measures, a special review is made on the symmetric mean absolute percentage error. Moreover, a new accuracy measure called the Unscaled Mean Bounded Relative Absolute Error (UMBRAE), which combines the best features of various alternative measures, is proposed to address the common issues of existing measures. A comparative evaluation on the proposed and related measures has been made with both synthetic and real-world data. The results indicate that the proposed measure, with user selectable benchmark, performs as well as or better than other measures on selected criteria. Though it has been commonly accepted that there is no single best accuracy measure, we suggest that UMBRAE could be a good choice to evaluate forecasting methods, especially for cases where measures based on geometric mean of relative errors, such as the geometric mean relative absolute error, are preferred. PMID:28339480

A new accuracy measure based on bounded relative error for time series forecasting.

PubMed

Chen, Chao; Twycross, Jamie; Garibaldi, Jonathan M

2017-01-01

Many accuracy measures have been proposed in the past for time series forecasting comparisons. However, many of these measures suffer from one or more issues such as poor resistance to outliers and scale dependence. In this paper, while summarising commonly used accuracy measures, a special review is made on the symmetric mean absolute percentage error. Moreover, a new accuracy measure called the Unscaled Mean Bounded Relative Absolute Error (UMBRAE), which combines the best features of various alternative measures, is proposed to address the common issues of existing measures. A comparative evaluation on the proposed and related measures has been made with both synthetic and real-world data. The results indicate that the proposed measure, with user selectable benchmark, performs as well as or better than other measures on selected criteria. Though it has been commonly accepted that there is no single best accuracy measure, we suggest that UMBRAE could be a good choice to evaluate forecasting methods, especially for cases where measures based on geometric mean of relative errors, such as the geometric mean relative absolute error, are preferred.

Spectral Accuracy and Sulfur Counting Capabilities of the LTQ-FT-ICR and the LTQ-Orbitrap XL for Small Molecule Analysis

NASA Astrophysics Data System (ADS)

Blake, Samantha L.; Walker, S. Hunter; Muddiman, David C.; Hinks, David; Beck, Keith R.

2011-12-01

Color Index Disperse Yellow 42 (DY42), a high-volume disperse dye for polyester, was used to compare the capabilities of the LTQ-Orbitrap XL and the LTQ-FT-ICR with respect to mass measurement accuracy (MMA), spectral accuracy, and sulfur counting. The results of this research will be used in the construction of a dye database for forensic purposes; the additional spectral information will increase the confidence in the identification of unknown dyes found in fibers at crime scenes. Initial LTQ-Orbitrap XL data showed MMAs greater than 3 ppm and poor spectral accuracy. Modification of several Orbitrap installation parameters (e.g., deflector voltage) resulted in a significant improvement of the data. The LTQ-FT-ICR and LTQ-Orbitrap XL (after installation parameters were modified) exhibited MMA ≤ 3 ppm, good spectral accuracy (χ2 values for the isotopic distribution ≤ 2), and were correctly able to ascertain the number of sulfur atoms in the compound at all resolving powers investigated for AGC targets of 5.00 × 105 and 1.00 × 106.

Fast and high-order numerical algorithms for the solution of multidimensional nonlinear fractional Ginzburg-Landau equation

NASA Astrophysics Data System (ADS)

Mohebbi, Akbar

2018-02-01

In this paper we propose two fast and accurate numerical methods for the solution of multidimensional space fractional Ginzburg-Landau equation (FGLE). In the presented methods, to avoid solving a nonlinear system of algebraic equations and to increase the accuracy and efficiency of method, we split the complex problem into simpler sub-problems using the split-step idea. For a homogeneous FGLE, we propose a method which has fourth-order of accuracy in time component and spectral accuracy in space variable and for nonhomogeneous one, we introduce another scheme based on the Crank-Nicolson approach which has second-order of accuracy in time variable. Due to using the Fourier spectral method for fractional Laplacian operator, the resulting schemes are fully diagonal and easy to code. Numerical results are reported in terms of accuracy, computational order and CPU time to demonstrate the accuracy and efficiency of the proposed methods and to compare the results with the analytical solutions. The results show that the present methods are accurate and require low CPU time. It is illustrated that the numerical results are in good agreement with the theoretical ones.

[Diagnostic performance of biliary ultrasound vs. magnetic resonance cholangiogram in patients with recurrent biliary obstruction.].

PubMed

Chávez-Valencia, V; Espinosa-Ortega, H F; Espinoza-Peralta, D; Arce-Salinas, C A

2009-01-01

Obstructive jaundice in patients with previous cholecystectomy requires a precise diagnosis. In the diagnostic algorithm, biliary ultrasound (BUS) and magnetic resonance cholangiogram (MRC) are used, although the accuracy of each method is unknown in our setting. No previous comparison of US and MRC in subjects with cholecystectomy has been made. To determine diagnostic accuracy of BUS and MRC in patients with recurrent biliary obstruction. Patients with endoscopic retrograde cholangiopacreatography (ERCP) demonstrating recurrent biliary obstruction by stones were included. All patients underwent BUS and MRC. We determined the diagnostic performance of each image study compared with ERCP. Twenty-seven patients with a mean age of 62.9 +/- 17.3 years-old were included. Sensitivity and specificity of BUS were 0.12 and 0.58, respectively. Figures for MRC were 0.88 and 0.82. Diagnostic agreement between ERCP and MRC was k= 0.66 whereas BUS had a k of only 0.26. MRC had good diagnostic performance for recurrent choledocolithiasis. BUS demonstrated lower accuracy compared with previous reports, so should not be considered in the initial approach of recurrent choledocus obstruction.

An easy-to-use semiquantitative food record validated for energy intake by using doubly labelled water technique.

PubMed

Koebnick, C; Wagner, K; Thielecke, F; Dieter, G; Höhne, A; Franke, A; Garcia, A L; Meyer, H; Hoffmann, I; Leitzmann, P; Trippo, U; Zunft, H J F

2005-09-01

Estimating dietary intake is important for both epidemiological and clinical studies, but often lacks accuracy. To investigate the accuracy and validity of energy intake estimated by an easy-to-use semiquantitative food record (EI(SQFR)) compared to total energy expenditure (TEE) estimated by doubly labelled water technique (EE(DLW)). TEE was measured in 29 nonobese subjects using the doubly labelled water method over a period of 14 days. Within this period, subjects reported their food consumption by a newly developed semiquantitative food record for 4 consecutive days. Energy intake was calculated using the German Food Code and Nutrition Data Base BLS II.3. A good correlation was observed between EI(SQFR) and EE(DLW) (r = 0.685, P < 0.001). The mean difference between EI(SQFR) and EE(DLW) was -1.7+/-2.6 MJ/day (-14+/-21%, P = 0.002). An underestimation of EI(SQFR) <10% was observed in nine subjects (31%), of 10-20% in six subjects (21%), and of >20% in nine subjects (31%). In five subjects (17%), an overestimation of EI(SQFR) was observed. The easy-to-use semiquantitative food record provided good estimates of EI in free-living and nonobese adults without prior detailed verbal instructions. The presented food record has limitations regarding accuracy at the individual level.

Taxonomic resolutions based on 18S rRNA genes: a case study of subclass copepoda.

PubMed

Wu, Shu; Xiong, Jie; Yu, Yuhe

2015-01-01

Biodiversity studies are commonly conducted using 18S rRNA genes. In this study, we compared the inter-species divergence of variable regions (V1-9) within the copepod 18S rRNA gene, and tested their taxonomic resolutions at different taxonomic levels. Our results indicate that the 18S rRNA gene is a good molecular marker for the study of copepod biodiversity, and our conclusions are as follows: 1) 18S rRNA genes are highly conserved intra-species (intra-species similarities are close to 100%); and could aid in species-level analyses, but with some limitations; 2) nearly-whole-length sequences and some partial regions (around V2, V4, and V9) of the 18S rRNA gene can be used to discriminate between samples at both the family and order levels (with a success rate of about 80%); 3) compared with other regions, V9 has a higher resolution at the genus level (with an identification success rate of about 80%); and 4) V7 is most divergent in length, and would be a good candidate marker for the phylogenetic study of Acartia species. This study also evaluated the correlation between similarity thresholds and the accuracy of using nuclear 18S rRNA genes for the classification of organisms in the subclass Copepoda. We suggest that sample identification accuracy should be considered when a molecular sequence divergence threshold is used for taxonomic identification, and that the lowest similarity threshold should be determined based on a pre-designated level of acceptable accuracy.

Taxonomic Resolutions Based on 18S rRNA Genes: A Case Study of Subclass Copepoda

PubMed Central

Wu, Shu; Xiong, Jie; Yu, Yuhe

2015-01-01

Biodiversity studies are commonly conducted using 18S rRNA genes. In this study, we compared the inter-species divergence of variable regions (V1–9) within the copepod 18S rRNA gene, and tested their taxonomic resolutions at different taxonomic levels. Our results indicate that the 18S rRNA gene is a good molecular marker for the study of copepod biodiversity, and our conclusions are as follows: 1) 18S rRNA genes are highly conserved intra-species (intra-species similarities are close to 100%); and could aid in species-level analyses, but with some limitations; 2) nearly-whole-length sequences and some partial regions (around V2, V4, and V9) of the 18S rRNA gene can be used to discriminate between samples at both the family and order levels (with a success rate of about 80%); 3) compared with other regions, V9 has a higher resolution at the genus level (with an identification success rate of about 80%); and 4) V7 is most divergent in length, and would be a good candidate marker for the phylogenetic study of Acartia species. This study also evaluated the correlation between similarity thresholds and the accuracy of using nuclear 18S rRNA genes for the classification of organisms in the subclass Copepoda. We suggest that sample identification accuracy should be considered when a molecular sequence divergence threshold is used for taxonomic identification, and that the lowest similarity threshold should be determined based on a pre-designated level of acceptable accuracy. PMID:26107258

The Strong Lensing Time Delay Challenge (2014)

NASA Astrophysics Data System (ADS)

Liao, Kai; Dobler, G.; Fassnacht, C. D.; Treu, T.; Marshall, P. J.; Rumbaugh, N.; Linder, E.; Hojjati, A.

2014-01-01

Time delays between multiple images in strong lensing systems are a powerful probe of cosmology. At the moment the application of this technique is limited by the number of lensed quasars with measured time delays. However, the number of such systems is expected to increase dramatically in the next few years. Hundred such systems are expected within this decade, while the Large Synoptic Survey Telescope (LSST) is expected to deliver of order 1000 time delays in the 2020 decade. In order to exploit this bounty of lenses we needed to make sure the time delay determination algorithms have sufficiently high precision and accuracy. As a first step to test current algorithms and identify potential areas for improvement we have started a "Time Delay Challenge" (TDC). An "evil" team has created realistic simulated light curves, to be analyzed blindly by "good" teams. The challenge is open to all interested parties. The initial challenge consists of two steps (TDC0 and TDC1). TDC0 consists of a small number of datasets to be used as a training template. The non-mandatory deadline is December 1 2013. The "good" teams that complete TDC0 will be given access to TDC1. TDC1 consists of thousands of lightcurves, a number sufficient to test precision and accuracy at the subpercent level, necessary for time-delay cosmography. The deadline for responding to TDC1 is July 1 2014. Submissions will be analyzed and compared in terms of predefined metrics to establish the goodness-of-fit, efficiency, precision and accuracy of current algorithms. This poster describes the challenge in detail and gives instructions for participation.

Evaluation of the accuracy of mono-energetic electron and beta-emitting isotope dose-point kernels using particle and heavy ion transport code system: PHITS.

PubMed

Shiiba, Takuro; Kuga, Naoya; Kuroiwa, Yasuyoshi; Sato, Tatsuhiko

2017-10-01

We assessed the accuracy of mono-energetic electron and beta-emitting isotope dose-point kernels (DPKs) calculated using the particle and heavy ion transport code system (PHITS) for patient-specific dosimetry in targeted radionuclide treatment (TRT) and compared our data with published data. All mono-energetic and beta-emitting isotope DPKs calculated using PHITS, both in water and compact bone, were in good agreement with those in literature using other MC codes. PHITS provided reliable mono-energetic electron and beta-emitting isotope scaled DPKs for patient-specific dosimetry. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reliability and accuracy analysis of a new semiautomatic radiographic measurement software in adult scoliosis.

PubMed

Aubin, Carl-Eric; Bellefleur, Christian; Joncas, Julie; de Lanauze, Dominic; Kadoury, Samuel; Blanke, Kathy; Parent, Stefan; Labelle, Hubert

2011-05-20

Radiographic software measurement analysis in adult scoliosis. To assess the accuracy as well as the intra- and interobserver reliability of measuring different indices on preoperative adult scoliosis radiographs using a novel measurement software that includes a calibration procedure and semiautomatic features to facilitate the measurement process. Scoliosis requires a careful radiographic evaluation to assess the deformity. Manual and computer radiographic process measures have been studied extensively to determine the reliability and reproducibility in adolescent idiopathic scoliosis. Most studies rely on comparing given measurements, which are repeated by the same user or by an expert user. A given measure with a small intra- or interobserver error might be deemed as good repeatability, but all measurements might not be truly accurate because the ground-truth value is often unknown. Thorough accuracy assessment of radiographic measures is necessary to assess scoliotic deformities, compare these measures at different stages or to permit valid multicenter studies. Thirty-four sets of adult scoliosis digital radiographs were measured two times by three independent observers using a novel radiographic measurement software that includes semiautomatic features to facilitate the measurement process. Twenty different measures taken from the Spinal Deformity Study Group radiographic measurement manual were performed on the coronal and sagittal images. Intra- and intermeasurer reliability for each measure was assessed. The accuracy of the measurement software was also assessed using a physical spine model in six different scoliotic configurations as a true reference. The majority of the measures demonstrated good to excellent intra- and intermeasurer reliability, except for sacral obliquity. The standard variation of all the measures was very small: ≤ 4.2° for Cobb angles, ≤ 4.2° for the kyphosis, ≤ 5.7° for the lordosis, ≤ 3.9° for the pelvic angles, and ≤5.3° for the sacral angles. The variability in the linear measurements (distances) was <4 mm. The variance of the measures was 1.7 and 2.6 times greater, respectively, for the angular and linear measures between the inter- and intrameasurer reliability. The image quality positively influenced the intermeasurer reliability especially for the proximal thoracic Cobb angle, T10-L2 lordosis, sacral slope and L5 seating. The accuracy study revealed that on average the difference in the angular measures was < 2° for the Cobb angles, and < 4° for the other angles, except T2-T12 kyphosis (5.3°). The linear measures were all <3.5 mm difference on average. The majority of the measures, which were analyzed in this study demonstrated good to excellent reliability and accuracy. The novel semiautomatic measurement software can be recommended for use for clinical, research or multicenter study purposes.

Communication Accuracy in Magazine Science Reporting.

ERIC Educational Resources Information Center

Borman, Susan Cray

1978-01-01

Evaluators with scientific expertise who analyzed the accuracy of popularized science news in mass circulation magazines found that the over-all accuracy of the magazine articles was good, and that the major problem was the omission of relevant information. (GW)

Competency-based assessment in surgeon-performed head and neck ultrasonography: A validity study.

PubMed

Todsen, Tobias; Melchiors, Jacob; Charabi, Birgitte; Henriksen, Birthe; Ringsted, Charlotte; Konge, Lars; von Buchwald, Christian

2018-06-01

Head and neck ultrasonography (HNUS) increasingly is used as a point-of-care diagnostic tool by otolaryngologists. However, ultrasonography (US) is a very operator-dependent image modality. Hence, this study aimed to explore the diagnostic accuracy of surgeon-performed HNUS and to establish validity evidence for an objective structured assessment of ultrasound skills (OSAUS) used for competency-based assessment. A prospective experimental study. Six otolaryngologists and 11 US novices were included in a standardized test setup for which they had to perform focused HNUS of eight patients suspected for different head and neck lesions. Their diagnostic accuracy was calculated based on the US reports, and two blinded raters assessed the video-recorded US performance using the OSAUS scale. The otolaryngologists obtained a high diagnostic accuracy on 88% (range 63%-100%) compared to the US novices on 38% (range 0-63%); P < 0.001. The OSAUS score demonstrated good inter-case reliability (0.85) and inter-rater reliability (0.76), and significant discrimination between otolaryngologist and US novices; P < 0.001. A strong correlation between the OSAUS score and the diagnostic accuracy was found (Spearman's ρ, 0.85; P < P 0.001), and a pass/fail score was established at 2.8. Strong validity evidence supported the use of the OSAUS scale to assess HNUS competence with good reliability, significant discrimination between US competence levels, and a strong correlation of assessment score to diagnostic accuracy. An OSAUS pass/fail score was established and could be used for competence-based assessment in surgeon-performed HNUS. NA. Laryngoscope, 128:1346-1352, 2018. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Comparison of GPS receiver DCB estimation methods using a GPS network

NASA Astrophysics Data System (ADS)

Choi, Byung-Kyu; Park, Jong-Uk; Min Roh, Kyoung; Lee, Sang-Jeong

2013-07-01

Two approaches for receiver differential code biases (DCB) estimation using the GPS data obtained from the Korean GPS network (KGN) in South Korea are suggested: the relative and single (absolute) methods. The relative method uses a GPS network, while the single method determines DCBs from a single station only. Their performance was assessed by comparing the receiver DCB values obtained from the relative method with those estimated by the single method. The daily averaged receiver DCBs obtained from the two different approaches showed good agreement for 7 days. The root mean square (RMS) value of those differences is 0.83 nanoseconds (ns). The standard deviation of the receiver DCBs estimated by the relative method was smaller than that of the single method. From these results, it is clear that the relative method can obtain more stable receiver DCBs compared with the single method over a short-term period. Additionally, the comparison between the receiver DCBs obtained by the Korea Astronomy and Space Science Institute (KASI) and those of the IGS Global Ionosphere Maps (GIM) showed a good agreement at 0.3 ns. As the accuracy of DCB values significantly affects the accuracy of ionospheric total electron content (TEC), more studies are needed to ensure the reliability and stability of the estimated receiver DCBs.

[Comparison of the accuracy of rectal endoscopic sonography and magnetic resonance imaging in the diagnosis of colorectal endometriosis].

PubMed

Kanté, F; Belghiti, J; Roseau, G; Thomassin-Naggara, I; Bazot, M; Daraï, E; Ballester, M

2017-03-01

To compare the accuracy of magnetic resonance imaging (MRI) and rectal endoscopic sonography (RES) for the diagnosis of colorectal endometriosis. In retrospective study, 407 patients operated on service of gynecology of Tenon hospital for deep endometriosis with suspected colorectal involvement. All patients underwent MRI and then RES. In the study, 239 patients (59%) had colorectal endometriosis which were diagnosed with the histology. The sensitivity, specificity, positive and negative predictive value (PPV and NPV) of RES and MRI for the diagnosis of colorectal endometriosis were respectively 92%, 87%, 91%, 88% and 85%, 88%, 91%, 80%. The accuracy of RES was not significantly different than MRI (90% versus 86%, P=0.09). RES is a good exam to diagnose colorectal endometriosis. It is able to improve diagnosis performances. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

An evaluation of image quality and accuracy of eye bank measurement of donor cornea endothelial cell density in the Specular Microscopy Ancillary Study.

PubMed

Lass, Jonathan H; Gal, Robin L; Ruedy, Katrina J; Benetz, Beth Ann; Beck, Roy W; Baratz, Keith H; Holland, Edward J; Kalajian, Andrea; Kollman, Craig; Manning, Francis J; Mannis, Mark J; McCoy, Kristen; Montoya, Monty; Stulting, Doyle; Xing, Dongyuan

2005-03-01

The Specular Microscopy Ancillary Study was designed to examine donor corneal endothelial specular image quality, compare the central endothelial cell density determined by eye banks with the endothelial cell density determined by a central specular microscopy reading center, and evaluate donor factors that may have an impact on specular image quality and endothelial cell density accuracy. Nonrandomized comparative trial. Endothelial specular images of donor corneas assigned in the Cornea Donor Study. Certified readers assessed donor image quality (analyzable from fair to excellent vs. unanalyzable) and determined the central endothelial cell density. Independent adjudication was performed if there was a difference in the quality of grading or if the endothelial cell density varied by > or =5.0% between readers. Average reading center-determined endothelial cell density was compared with the endothelial cell density determined by each eye bank. Evaluation of image quality and accuracy of endothelial cell density. Of 688 donor endothelial images submitted by 23 eye banks, 663 (96%) were analyzable (excellent, 40 [6%]; good, 302 [44%]; fair, 321 [47%]), and 25 (4%) were unanalyzable by reading center standards. In situ retrieval and greater epithelial exposure correlated with a higher image quality grading. The eye bank-determined endothelial cell density of 434 of the 663 (65%) analyzable images were within 10% of the endothelial cell density determined by the reading center, whereas 185 (28%) were more than 10% higher and 44 (7%) were more than 10% lower. Greater variation in endothelial cell density between the eye banks and the reading center was observed with shorter time of death to preservation, presence of an epithelial defect, folds in Descemet's membrane, lower image quality, and the use of fixed-frame or center method endothelial cell density analysis. Overall, donor endothelial specular image quality and accuracy of endothelial cell density determination were good. However, the data suggest that factors that may affect image quality and contribute to variation in interpretation of the endothelial cell density should be addressed, because the donor endothelial cell density is an important parameter for assessing long-term corneal graft survival.

Interim heterogeneity changes measured using entropy texture features on T2-weighted MRI at 3.0 T are associated with pathological response to neoadjuvant chemotherapy in primary breast cancer.

PubMed

Henderson, Shelley; Purdie, Colin; Michie, Caroline; Evans, Andrew; Lerski, Richard; Johnston, Marilyn; Vinnicombe, Sarah; Thompson, Alastair M

2017-11-01

To investigate whether interim changes in hetereogeneity (measured using entropy features) on MRI were associated with pathological residual cancer burden (RCB) at final surgery in patients receiving neoadjuvant chemotherapy (NAC) for primary breast cancer. This was a retrospective study of 88 consenting women (age: 30-79 years). Scanning was performed on a 3.0 T MRI scanner prior to NAC (baseline) and after 2-3 cycles of treatment (interim). Entropy was derived from the grey-level co-occurrence matrix, on slice-matched baseline/interim T2-weighted images. Response, assessed using RCB score on surgically resected specimens, was compared statistically with entropy/heterogeneity changes and ROC analysis performed. Association of pCR within each tumour immunophenotype was evaluated. Mean entropy percent differences between examinations, by response category, were: pCR: 32.8%, RCB-I: 10.5%, RCB-II: 9.7% and RCB-III: 3.0%. Association of ultimate pCR with coarse entropy changes between baseline/interim MRI across all lesions yielded 85.2% accuracy (area under ROC curve: 0.845). Excellent sensitivity/specificity was obtained for pCR prediction within each immunophenotype: ER+: 100%/100%; HER2+: 83.3%/95.7%, TNBC: 87.5%/80.0%. Lesion T2 heterogeneity changes are associated with response to NAC using RCB scores, particularly for pCR, and can be useful across all immunophenotypes with good diagnostic accuracy. • Texture analysis provides a means of measuring lesion heterogeneity on MRI images. • Heterogeneity changes between baseline/interim MRI can be linked with ultimate pathological response. • Heterogeneity changes give good diagnostic accuracy of pCR response across all immunophenotypes. • Percentage reduction in heterogeneity is associated with pCR with good accuracy and NPV.

Perspectives of Maine Forest Cover Change from Landsat Imagery and Forest Inventory Analysis (FIA)

Treesearch

Steven Sader; Michael Hoppus; Jacob Metzler; Suming Jin

2005-01-01

A forest change detection map was developed to document forest gains and losses during the decade of the 1990s. The effectiveness of the Landsat imagery and methods for detecting Maine forest cover change are indicated by the good accuracy assessment results: forest-no change, forest loss, and forest gain accuracy were 90, 88, and 92% respectively, and the good...

Ontario multidetector computed tomographic coronary angiography study: field evaluation of diagnostic accuracy.

PubMed

Chow, Benjamin J W; Freeman, Michael R; Bowen, James M; Levin, Leslie; Hopkins, Robert B; Provost, Yves; Tarride, Jean-Eric; Dennie, Carole; Cohen, Eric A; Marcuzzi, Dan; Iwanochko, Robert; Moody, Alan R; Paul, Narinder; Parker, John D; O'Reilly, Daria J; Xie, Feng; Goeree, Ron

2011-06-13

Computed tomographic coronary angiography (CTCA) has gained clinical acceptance for the detection of obstructive coronary artery disease. Although single-center studies have demonstrated excellent accuracy, multicenter studies have yielded variable results. The true diagnostic accuracy of CTCA in the "real world" remains uncertain. We conducted a field evaluation comparing multidetector CTCA with invasive CA (ICA) to understand CTCA's diagnostic accuracy in a real-world setting. A multicenter cohort study of patients awaiting ICA was conducted between September 2006 and June 2009. All patients had either a low or an intermediate pretest probability for coronary artery disease and underwent CTCA and ICA within 10 days. The results of CTCA and ICA were interpreted visually by local expert observers who were blinded to all clinical data and imaging results. Using a patient-based analysis (diameter stenosis ≥50%) of 169 patients, the sensitivity, specificity, positive predictive value, and negative predictive value were 81.3% (95% confidence interval [CI], 71.0%-89.1%), 93.3% (95% CI, 85.9%-97.5%), 91.6% (95% CI, 82.5%-96.8%), and 84.7% (95% CI, 76.0%-91.2%), respectively; the area under receiver operating characteristic curve was 0.873. The diagnostic accuracy varied across centers (P < .001), with a sensitivity, specificity, positive predictive value, and negative predictive value ranging from 50.0% to 93.2%, 92.0% to 100%, 84.6% to 100%, and 42.9% to 94.7%, respectively. Compared with ICA, CTCA appears to have good accuracy; however, there was variability in diagnostic accuracy across centers. Factors affecting institutional variability need to be better understood before CTCA is universally adopted. Additional real-world evaluations are needed to fully understand the impact of CTCA on clinical care. clinicaltrials.gov Identifier: NCT00371891.

A survey of the dummy face and human face stimuli used in BCI paradigm.

PubMed

Chen, Long; Jin, Jing; Zhang, Yu; Wang, Xingyu; Cichocki, Andrzej

2015-01-15

It was proved that the human face stimulus were superior to the flash only stimulus in BCI system. However, human face stimulus may lead to copyright infringement problems and was hard to be edited according to the requirement of the BCI study. Recently, it was reported that facial expression changes could be done by changing a curve in a dummy face which could obtain good performance when it was applied to visual-based P300 BCI systems. In this paper, four different paradigms were presented, which were called dummy face pattern, human face pattern, inverted dummy face pattern and inverted human face pattern, to evaluate the performance of the dummy faces stimuli compared with the human faces stimuli. The key point that determined the value of dummy faces in BCI systems were whether dummy faces stimuli could obtain as good performance as human faces stimuli. Online and offline results of four different paradigms would have been obtained and comparatively analyzed. Online and offline results showed that there was no significant difference among dummy faces and human faces in ERPs, classification accuracy and information transfer rate when they were applied in BCI systems. Dummy faces stimuli could evoke large ERPs and obtain as high classification accuracy and information transfer rate as the human faces stimuli. Since dummy faces were easy to be edited and had no copyright infringement problems, it would be a good choice for optimizing the stimuli of BCI systems. Copyright © 2014 Elsevier B.V. All rights reserved.

a Band Selection Method for High Precision Registration of Hyperspectral Image

NASA Astrophysics Data System (ADS)

Yang, H.; Li, X.

2018-04-01

During the registration of hyperspectral images and high spatial resolution images, too much bands in a hyperspectral image make it difficult to select bands with good registration performance. Terrible bands are possible to reduce matching speed and accuracy. To solve this problem, an algorithm based on Cram'er-Rao lower bound theory is proposed to select good matching bands in this paper. The algorithm applies the Cram'er-Rao lower bound theory to the study of registration accuracy, and selects good matching bands by CRLB parameters. Experiments show that the algorithm in this paper can choose good matching bands and provide better data for the registration of hyperspectral image and high spatial resolution image.

Accuracy of Monte Carlo simulations compared to in-vivo MDCT dosimetry

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

Bostani, Maryam, E-mail: mbostani@mednet.ucla.edu; McMillan, Kyle; Cagnon, Chris H.

Purpose: The purpose of this study was to assess the accuracy of a Monte Carlo simulation-based method for estimating radiation dose from multidetector computed tomography (MDCT) by comparing simulated doses in ten patients to in-vivo dose measurements. Methods: MD Anderson Cancer Center Institutional Review Board approved the acquisition of in-vivo rectal dose measurements in a pilot study of ten patients undergoing virtual colonoscopy. The dose measurements were obtained by affixing TLD capsules to the inner lumen of rectal catheters. Voxelized patient models were generated from the MDCT images of the ten patients, and the dose to the TLD for allmore » exposures was estimated using Monte Carlo based simulations. The Monte Carlo simulation results were compared to the in-vivo dose measurements to determine accuracy. Results: The calculated mean percent difference between TLD measurements and Monte Carlo simulations was −4.9% with standard deviation of 8.7% and a range of −22.7% to 5.7%. Conclusions: The results of this study demonstrate very good agreement between simulated and measured doses in-vivo. Taken together with previous validation efforts, this work demonstrates that the Monte Carlo simulation methods can provide accurate estimates of radiation dose in patients undergoing CT examinations.« less

Combining diffusion-weighted MRI with Gd-EOB-DTPA-enhanced MRI improves the detection of colorectal liver metastases.

PubMed

Koh, D-M; Collins, D J; Wallace, T; Chau, I; Riddell, A M

2012-07-01

To compare the diagnostic accuracy of gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MRI, diffusion-weighted MRI (DW-MRI) and a combination of both techniques for the detection of colorectal hepatic metastases. 72 patients with suspected colorectal liver metastases underwent Gd-EOB-DTPA MRI and DW-MRI. Images were retrospectively reviewed with unenhanced T(1) and T(2) weighted images as Gd-EOB-DTPA image set, DW-MRI image set and combined image set by two independent radiologists. Each lesion detected was scored for size, location and likelihood of metastasis, and compared with surgery and follow-up imaging. Diagnostic accuracy was compared using receiver operating characteristics and interobserver agreement by kappa statistics. 417 lesions (310 metastases, 107 benign) were found in 72 patients. For both readers, diagnostic accuracy using the combined image set was higher [area under the curve (Az)=0.96, 0.97] than Gd-EOB-DTPA image set (Az=0.86, 0.89) or DW-MRI image set (Az=0.93, 0.92). Using combined image set improved identification of liver metastases compared with Gd-EOB-DTPA image set (p<0.001) or DW-MRI image set (p<0.001). There was very good interobserver agreement for lesion classification (κ=0.81-0.88). Combining DW-MRI with Gd-EOB-DTPA-enhanced T(1) weighted MRI significantly improved the detection of colorectal liver metastases.

Static bending deflection and free vibration analysis of moderate thick symmetric laminated plates using multidimensional wave digital filters

NASA Astrophysics Data System (ADS)

Tseng, Chien-Hsun

2018-06-01

This paper aims to develop a multidimensional wave digital filtering network for predicting static and dynamic behaviors of composite laminate based on the FSDT. The resultant network is, thus, an integrated platform that can perform not only the free vibration but also the bending deflection of moderate thick symmetric laminated plates with low plate side-to-thickness ratios (< = 20). Safeguarded by the Courant-Friedrichs-Levy stability condition with the least restriction in terms of optimization technique, the present method offers numerically high accuracy, stability and efficiency to proceed a wide range of modulus ratios for the FSDT laminated plates. Instead of using a constant shear correction factor (SCF) with a limited numerical accuracy for the bending deflection, an optimum SCF is particularly sought by looking for a minimum ratio of change in the transverse shear energy. This way, it can predict as good results in terms of accuracy for certain cases of bending deflection. Extensive simulation results carried out for the prediction of maximum bending deflection have demonstratively proven that the present method outperforms those based on the higher-order shear deformation and layerwise plate theories. To the best of our knowledge, this is the first work that shows an optimal selection of SCF can significantly increase the accuracy of FSDT-based laminates especially compared to the higher order theory disclaiming any correction. The highest accuracy of overall solution is compared to the 3D elasticity equilibrium one.

Real-Time Tropospheric Product Establishment and Accuracy Assessment in China

NASA Astrophysics Data System (ADS)

Chen, M.; Guo, J.; Wu, J.; Song, W.; Zhang, D.

2018-04-01

Tropospheric delay has always been an important issue in Global Navigation Satellite System (GNSS) processing. Empirical tropospheric delay models are difficult to simulate complex and volatile atmospheric environments, resulting in poor accuracy of the empirical model and difficulty in meeting precise positioning demand. In recent years, some scholars proposed to establish real-time tropospheric product by using real-time or near-real-time GNSS observations in a small region, and achieved some good results. This paper uses real-time observing data of 210 Chinese national GNSS reference stations to estimate the tropospheric delay, and establishes ZWD grid model in the country wide. In order to analyze the influence of tropospheric grid product on wide-area real-time PPP, this paper compares the method of taking ZWD grid product as a constraint with the model correction method. The results show that the ZWD grid product estimated based on the national reference stations can improve PPP accuracy and convergence speed. The accuracy in the north (N), east (E) and up (U) direction increase by 31.8 %,15.6 % and 38.3 %, respectively. As with the convergence speed, the accuracy of U direction experiences the most improvement.

New potentiometric transducer based on a Mn(II) [2-formylquinoline thiosemicarbazone] complex for static and hydrodynamic assessment of azides.

PubMed

Kamel, Ayman H

2015-11-01

A new potentiometric transducer for selective recognition of azide is characterized and developed. The PVC plasticized based sensor incorporates Mn(II) [2-formylquinoline thiosemicarbazone] complex in the presence of tri dodecyl methyl ammonium chloride (TDMAC) as a lipophilic cationic additive. The sensor displayed a near-Nernstian response for azide over 1.0×10(-2)-1.0×10(-5) mol L(-1), with an anionic slope of -55.8±0.6 mV decade(-1) and lower limit of detection 0.34 µg mL(-1). The sensor was pH independent in the range 5.5-9 and presented good selectivity features towards several inorganic anions, and it is easily used in a flow injection system and compared with a tubular detector. The intrinsic characteristics of the detector in a low dispersion manifold were determined and compared with data obtained under a hydrodynamic mode of operation. This simple and inexpensive automation, with a good potentiometric detector, enabled the analysis of ~33 samples h(-1) without requiring pre-treatment procedures. The proposed method is also applied to the analysis of trace levels of azide in primer mixtures. Significantly improved accuracy, precision, response time, stability and selectivity were offered by these simple and cost-effective potentiometric sensor compared with other standard techniques. The method has the requisite accuracy, sensitivity and precision to determine azide ions. Copyright © 2015 Elsevier B.V. All rights reserved.

Rule extraction from minimal neural networks for credit card screening.

PubMed

Setiono, Rudy; Baesens, Bart; Mues, Christophe

2011-08-01

While feedforward neural networks have been widely accepted as effective tools for solving classification problems, the issue of finding the best network architecture remains unresolved, particularly so in real-world problem settings. We address this issue in the context of credit card screening, where it is important to not only find a neural network with good predictive performance but also one that facilitates a clear explanation of how it produces its predictions. We show that minimal neural networks with as few as one hidden unit provide good predictive accuracy, while having the added advantage of making it easier to generate concise and comprehensible classification rules for the user. To further reduce model size, a novel approach is suggested in which network connections from the input units to this hidden unit are removed by a very straightaway pruning procedure. In terms of predictive accuracy, both the minimized neural networks and the rule sets generated from them are shown to compare favorably with other neural network based classifiers. The rules generated from the minimized neural networks are concise and thus easier to validate in a real-life setting.

Comparison between calculation and measured data on secondary neutron energy spectra by heavy ion reactions from different thick targets.

PubMed

Iwase, H; Wiegel, B; Fehrenbacher, G; Schardt, D; Nakamura, T; Niita, K; Radon, T

2005-01-01

Measured neutron energy fluences from high-energy heavy ion reactions through targets several centimeters to several hundred centimeters thick were compared with calculations made using the recently developed general-purpose particle and heavy ion transport code system (PHITS). It was confirmed that the PHITS represented neutron production by heavy ion reactions and neutron transport in thick shielding with good overall accuracy.

MRI Interscanner Agreement of the Association between the Susceptibility Vessel Sign and Histologic Composition of Thrombi.

PubMed

Bourcier, Romain; Détraz, Lili; Serfaty, Jean Michel; Delasalle, Beatrice Guyomarch; Mirza, Mahmood; Derraz, Imad; Toulgoat, Frédérique; Naggara, Olivier; Toquet, Claire; Desal, Hubert

2017-11-01

The susceptibility vessel sign (SVS) on magnetic resonance imaging (MRI) is related to thrombus location, composition, and size in acute stroke. No previous study has determined its inter-MRI scanner variability. We aimed to compare the diagnostic accuracy in-vitro of four different MRI scanners for the characterization of histologic thrombus composition. Thirty-five manufactured thrombi analogs of different composition that were histologically categorized as fibrin-dominant, mixed, or red blood cell (RBC)-dominant were scanned on four different MRI units with T2* sequence. Nine radiologists, blinded to thrombus composition and MRI scanner model, classified twice, in a 2-week interval, the SVS of each thrombus as absent, questionable, or present. We calculated the weighted kappa with 95% confidence interval (CI), sensitivity, specificity and accuracy of the SVS on each MRI scanner to detect RBC-dominant thrombi. The SVS was present in 42%, absent in 33%, and questionable in 25% of thrombi. The interscanner agreement was moderate to good, ranging from .45 (CI: .37-.52) to .67 (CI: .61-.74). The correlation between the SVS and the thrombus composition was moderate (κ: .50 [CI: .44-.55]) to good κ: .76 ([CI: .72-.80]). Sensitivity, specificity, and accuracy to identify RBC-dominant clots were significantly different between MRI scanners (P < .001). The diagnostic accuracy of SVS to determine thrombus composition varies significantly among MRI scanners. Normalization of T2*sequences between scanners may be needed to better predict thrombus composition in multicenter studies. Copyright © 2017 by the American Society of Neuroimaging.

Contrast-enhanced small-animal PET/CT in cancer research: strong improvement of diagnostic accuracy without significant alteration of quantitative accuracy and NEMA NU 4-2008 image quality parameters.

PubMed

Lasnon, Charline; Quak, Elske; Briand, Mélanie; Gu, Zheng; Louis, Marie-Hélène; Aide, Nicolas

2013-01-17

The use of iodinated contrast media in small-animal positron emission tomography (PET)/computed tomography (CT) could improve anatomic referencing and tumor delineation but may introduce inaccuracies in the attenuation correction of the PET images. This study evaluated the diagnostic performance and accuracy of quantitative values in contrast-enhanced small-animal PET/CT (CEPET/CT) as compared to unenhanced small animal PET/CT (UEPET/CT). Firstly, a NEMA NU 4-2008 phantom (filled with 18F-FDG or 18F-FDG plus contrast media) and a homemade phantom, mimicking an abdominal tumor surrounded by water or contrast media, were used to evaluate the impact of iodinated contrast media on the image quality parameters and accuracy of quantitative values for a pertinent-sized target. Secondly, two studies in 22 abdominal tumor-bearing mice and rats were performed. The first animal experiment studied the impact of a dual-contrast media protocol, comprising the intravenous injection of a long-lasting contrast agent mixed with 18F-FDG and the intraperitoneal injection of contrast media, on tumor delineation and the accuracy of quantitative values. The second animal experiment compared the diagnostic performance and quantitative values of CEPET/CT versus UEPET/CT by sacrificing the animals after the tracer uptake period and imaging them before and after intraperitoneal injection of contrast media. There was minimal impact on IQ parameters (%SDunif and spillover ratios in air and water) when the NEMA NU 4-2008 phantom was filled with 18F-FDG plus contrast media. In the homemade phantom, measured activity was similar to true activity (-0.02%) and overestimated by 10.30% when vials were surrounded by water or by an iodine solution, respectively. The first animal experiment showed excellent tumor delineation and a good correlation between small-animal (SA)-PET and ex vivo quantification (r2 = 0.87, P < 0.0001). The second animal experiment showed a good correlation between CEPET/CT and UEPET/CT quantitative values (r2 = 0.99, P < 0.0001). Receiver operating characteristic analysis demonstrated better diagnostic accuracy of CEPET/CT versus UEPET/CT (senior researcher, area under the curve (AUC) 0.96 versus 0.77, P = 0.004; junior researcher, AUC 0.78 versus 0.58, P = 0.004). The use of iodinated contrast media for small-animal PET imaging significantly improves tumor delineation and diagnostic performance, without significant alteration of SA-PET quantitative accuracy and NEMA NU 4-2008 IQ parameters.

LBP and SIFT based facial expression recognition

NASA Astrophysics Data System (ADS)

Sumer, Omer; Gunes, Ece O.

2015-02-01

This study compares the performance of local binary patterns (LBP) and scale invariant feature transform (SIFT) with support vector machines (SVM) in automatic classification of discrete facial expressions. Facial expression recognition is a multiclass classification problem and seven classes; happiness, anger, sadness, disgust, surprise, fear and comtempt are classified. Using SIFT feature vectors and linear SVM, 93.1% mean accuracy is acquired on CK+ database. On the other hand, the performance of LBP-based classifier with linear SVM is reported on SFEW using strictly person independent (SPI) protocol. Seven-class mean accuracy on SFEW is 59.76%. Experiments on both databases showed that LBP features can be used in a fairly descriptive way if a good localization of facial points and partitioning strategy are followed.

Dental cementum in age estimation: a polarized light and stereomicroscopic study.

PubMed

Kasetty, Sowmya; Rammanohar, M; Raju Ragavendra, T

2010-05-01

Dental hard tissues are good candidates for age estimation as they are less destructive and procedures to determine age can be easily performed. Although cementum annulations and cementum thickness are important parameters in this regard, they are seldom used. This study was undertaken to review the methods, difficulties in execution of techniques, and accuracy of cementum thickness and annulations in estimating the age. Unstained and stained ground sections of tooth were used to measure cemental thickness and count cemental annulations based on which age was estimated and was compared with known age. Although there was positive relation between cemental thickness and annulations with age, only in 1-1.5% of cases, age could be predicted with accuracy.

On the accuracy of the 'decoupled l-dominant' approximation for atom-molecule scattering

NASA Technical Reports Server (NTRS)

Green, S.

1976-01-01

Cross sections for rotational excitation and spectral pressure broadening of HD, HCl, CO, and HCN due to collisions with low energy He atoms have been computed within the 'decoupled l-dominant' (DLD) approximation and are compared with accurate close coupling results and also with two similar approximations, the effective potential of Rabitz and the coupled states of McGuire and Kouri. DLD predictions of state-to-state cross sections are rather good, being only slightly less accurate than coupled states results. DLD is far superior to either the coupled states or effective potential methods for pressure broadening calculations, although it may not be uniformly of the quantitative accuracy desirable for obtaining intermolecular potentials from experimental data.

Application of the boundary integral method to immiscible displacement problems

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

Masukawa, J.; Horne, R.N.

1988-08-01

This paper presents an application of the boundary integral method (BIM) to fluid displacement problems to demonstrate its usefulness in reservoir simulation. A method for solving two-dimensional (2D), piston-like displacement for incompressible fluids with good accuracy has been developed. Several typical example problems with repeated five-spot patterns were solved for various mobility ratios. The solutions were compared with the analytical solutions to demonstrate accuracy. Singularity programming was found to be a major advantage in handling flow in the vicinity of wells. The BIM was found to be an excellent way to solve immiscible displacement problems. Unlike analytic methods, it canmore » accommodate complex boundary shapes and does not suffer from numerical dispersion at the front.« less

Fatigue life prediction of rotor blade composites: Validation of constant amplitude formulations with variable amplitude experiments

NASA Astrophysics Data System (ADS)

Westphal, T.; Nijssen, R. P. L.

2014-12-01

The effect of Constant Life Diagram (CLD) formulation on the fatigue life prediction under variable amplitude (VA) loading was investigated based on variable amplitude tests using three different load spectra representative for wind turbine loading. Next to the Wisper and WisperX spectra, the recently developed NewWisper2 spectrum was used. Based on these variable amplitude fatigue results the prediction accuracy of 4 CLD formulations is investigated. In the study a piecewise linear CLD based on the S-N curves for 9 load ratios compares favourably in terms of prediction accuracy and conservativeness. For the specific laminate used in this study Boerstra's Multislope model provides a good alternative at reduced test effort.

Model-based RSA of a femoral hip stem using surface and geometrical shape models.

PubMed

Kaptein, Bart L; Valstar, Edward R; Spoor, Cees W; Stoel, Berend C; Rozing, Piet M

2006-07-01

Roentgen stereophotogrammetry (RSA) is a highly accurate three-dimensional measuring technique for assessing micromotion of orthopaedic implants. A drawback is that markers have to be attached to the implant. Model-based techniques have been developed to prevent using special marked implants. We compared two model-based RSA methods with standard marker-based RSA techniques. The first model-based RSA method used surface models, and the second method used elementary geometrical shape (EGS) models. We used a commercially available stem to perform experiments with a phantom as well as reanalysis of patient RSA radiographs. The data from the phantom experiment indicated the accuracy and precision of the elementary geometrical shape model-based RSA method is equal to marker-based RSA. For model-based RSA using surface models, the accuracy is equal to the accuracy of marker-based RSA, but its precision is worse. We found no difference in accuracy and precision between the two model-based RSA techniques in clinical data. For this particular hip stem, EGS model-based RSA is a good alternative for marker-based RSA.

External validation and comparison of two nomograms predicting the probability of Gleason sum upgrading between biopsy and radical prostatectomy pathology in two patient populations: a retrospective cohort study.

PubMed

Utsumi, Takanobu; Oka, Ryo; Endo, Takumi; Yano, Masashi; Kamijima, Shuichi; Kamiya, Naoto; Fujimura, Masaaki; Sekita, Nobuyuki; Mikami, Kazuo; Hiruta, Nobuyuki; Suzuki, Hiroyoshi

2015-11-01

The aim of this study is to validate and compare the predictive accuracy of two nomograms predicting the probability of Gleason sum upgrading between biopsy and radical prostatectomy pathology among representative patients with prostate cancer. We previously developed a nomogram, as did Chun et al. In this validation study, patients originated from two centers: Toho University Sakura Medical Center (n = 214) and Chibaken Saiseikai Narashino Hospital (n = 216). We assessed predictive accuracy using area under the curve values and constructed calibration plots to grasp the tendency for each institution. Both nomograms showed a high predictive accuracy in each institution, although the constructed calibration plots of the two nomograms underestimated the actual probability in Toho University Sakura Medical Center. Clinicians need to use calibration plots for each institution to correctly understand the tendency of each nomogram for their patients, even if each nomogram has a good predictive accuracy. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A new algorithm for microwave delay estimation from water vapor radiometer data

NASA Technical Reports Server (NTRS)

Robinson, S. E.

1986-01-01

A new algorithm has been developed for the estimation of tropospheric microwave path delays from water vapor radiometer (WVR) data, which does not require site and weather dependent empirical parameters to produce high accuracy. Instead of taking the conventional linear approach, the new algorithm first uses the observables with an emission model to determine an approximate form of the vertical water vapor distribution which is then explicitly integrated to estimate wet path delays, in a second step. The intrinsic accuracy of this algorithm has been examined for two channel WVR data using path delays and stimulated observables computed from archived radiosonde data. It is found that annual RMS errors for a wide range of sites are in the range from 1.3 mm to 2.3 mm, in the absence of clouds. This is comparable to the best overall accuracy obtainable from conventional linear algorithms, which must be tailored to site and weather conditions using large radiosonde data bases. The new algorithm's accuracy and flexibility are indications that it may be a good candidate for almost all WVR data interpretation.

Data capture by digital pen in clinical trials: a qualitative and quantitative study.

PubMed

Estellat, Candice; Tubach, Florence; Costa, Yolande; Hoffmann, Isabelle; Mantz, Jean; Ravaud, Philippe

2008-05-01

To investigate the use of the digital pen (DP) system to collect data in a clinical trial. To assess the accuracy of the system in this setting. Qualitative study based on semistructured interviews and a focus group. Quantitative study comparing the DP system and a double manual data-entry system in accuracy of acquiring data by variable type (tick boxes, dates, numbers, letters). An ongoing randomised multicentric clinical trial in tertiary care in France. 27 investigators involved in the trial (anaesthetists) who did or did not include patients, 4 study monitors and the study coordinator. Six key findings emerged: 1) the DP system was easy to use; its utilisation was intuitive, even for investigators inexperienced in informatics; 2) despite its portability, the DP was not always used in front of patients; 3) the DP system did not affect patient recruitment; 4) most of the technical problems of the system occurred during setup (compatibility, password access, antivirus software); 5) the main advantage was quickness of data availability for the study coordination staff and the main hindrance was the extra time required for online verification; and 6) all investigators were ready to use the system again. The investigators had to check 16% of data obtained by the DP system during the verification step. There is no relevant difference between the number of errors for the DP and the double manual data-entry systems: 8/5022 versus 6/5022 data entries. 5 out of 8 DP-system failures were due to the intelligent character recognition system. The DP system has a good acceptability among all investigators in a clinical setting, whether they are experienced with computers or not, and a good accuracy, as compared with double manual data entry.

Prediction of the spectral reflectance of laser-generated color prints by combination of an optical model and learning methods.

PubMed

Nébouy, David; Hébert, Mathieu; Fournel, Thierry; Larina, Nina; Lesur, Jean-Luc

2015-09-01

Recent color printing technologies based on the principle of revealing colors on pre-functionalized achromatic supports by laser irradiation offer advanced functionalities, especially for security applications. However, for such technologies, the color prediction is challenging, compared to classic ink-transfer printing systems. The spectral properties of the coloring materials modified by the lasers are not precisely known and may strongly vary, depending on the laser settings, in a nonlinear manner. We show in this study, through the example of the color laser marking (CLM) technology, based on laser bleaching of a mixture of pigments, that the combination of an adapted optical reflectance model and learning methods to get the model's parameters enables prediction of the spectral reflectance of any printable color with rather good accuracy. Even though the pigment mixture is formulated from three colored pigments, an analysis of the dimensionality of the spectral space generated by CLM printing, thanks to a principal component analysis decomposition, shows that at least four spectral primaries are needed for accurate spectral reflectance predictions. A polynomial interpolation is then used to relate RGB laser intensities with virtual coordinates of new basis vectors. By studying the influence of the number of calibration patches on the prediction accuracy, we can conclude that a reasonable number of 130 patches are enough to achieve good accuracy in this application.

The German version of the Posttraumatic Stress Disorder Checklist for DSM-5 (PCL-5): psychometric properties and diagnostic utility.

PubMed

Krüger-Gottschalk, Antje; Knaevelsrud, Christine; Rau, Heinrich; Dyer, Anne; Schäfer, Ingo; Schellong, Julia; Ehring, Thomas

2017-11-28

The Posttraumatic Stress Disorder (PTSD) Checklist (PCL, now PCL-5) has recently been revised to reflect the new diagnostic criteria of the disorder. A clinical sample of trauma-exposed individuals (N = 352) was assessed with the Clinician Administered PTSD Scale for DSM-5 (CAPS-5) and the PCL-5. Internal consistencies and test-retest reliability were computed. To investigate diagnostic accuracy, we calculated receiver operating curves. Confirmatory factor analyses (CFA) were performed to analyze the structural validity. Results showed high internal consistency (α = .95), high test-retest reliability (r = .91) and a high correlation with the total severity score of the CAPS-5, r = .77. In addition, the recommended cutoff of 33 on the PCL-5 showed high diagnostic accuracy when compared to the diagnosis established by the CAPS-5. CFAs comparing the DSM-5 model with alternative models (the three-factor solution, the dysphoria, anhedonia, externalizing behavior and hybrid model) to account for the structural validity of the PCL-5 remained inconclusive. Overall, the findings show that the German PCL-5 is a reliable instrument with good diagnostic accuracy. However, more research evaluating the underlying factor structure is needed.

Dynamic comparisons of piezoelectric ejecta diagnostics

NASA Astrophysics Data System (ADS)

Buttler, W. T.; Zellner, M. B.; Olson, R. T.; Rigg, P. A.; Hixson, R. S.; Hammerberg, J. E.; Obst, A. W.; Payton, J. R.; Iverson, A.; Young, J.

2007-03-01

We investigate the quantitative reliability and precision of three different piezoelectric technologies for measuring ejected areal mass from shocked surfaces. Specifically we performed ejecta measurements on Sn shocked at two pressures, P ≈215 and 235 kbar. The shock in the Sn was created by launching a impactor with a powder gun. We self-compare and cross-compare these measurements to assess the ability of these probes to precisely determine the areal mass ejected from a shocked surface. We demonstrate the precision of each technology to be good, with variabilities on the order of ±10%. We also discuss their relative accuracy.

Forecasting the value of credit scoring

NASA Astrophysics Data System (ADS)

Saad, Shakila; Ahmad, Noryati; Jaffar, Maheran Mohd

2017-08-01

Nowadays, credit scoring system plays an important role in banking sector. This process is important in assessing the creditworthiness of customers requesting credit from banks or other financial institutions. Usually, the credit scoring is used when customers send the application for credit facilities. Based on the score from credit scoring, bank will be able to segregate the "good" clients from "bad" clients. However, in most cases the score is useful at that specific time only and cannot be used to forecast the credit worthiness of the same applicant after that. Hence, bank will not know if "good" clients will always be good all the time or "bad" clients may become "good" clients after certain time. To fill up the gap, this study proposes an equation to forecast the credit scoring of the potential borrowers at a certain time by using the historical score related to the assumption. The Mean Absolute Percentage Error (MAPE) is used to measure the accuracy of the forecast scoring. Result shows the forecast scoring is highly accurate as compared to actual credit scoring.

A hybrid PSO-SVM-based method for predicting the friction coefficient between aircraft tire and coating

NASA Astrophysics Data System (ADS)

Zhan, Liwei; Li, Chengwei

2017-02-01

A hybrid PSO-SVM-based model is proposed to predict the friction coefficient between aircraft tire and coating. The presented hybrid model combines a support vector machine (SVM) with particle swarm optimization (PSO) technique. SVM has been adopted to solve regression problems successfully. Its regression accuracy is greatly related to optimizing parameters such as the regularization constant C , the parameter gamma γ corresponding to RBF kernel and the epsilon parameter \\varepsilon in the SVM training procedure. However, the friction coefficient which is predicted based on SVM has yet to be explored between aircraft tire and coating. The experiment reveals that drop height and tire rotational speed are the factors affecting friction coefficient. Bearing in mind, the friction coefficient can been predicted using the hybrid PSO-SVM-based model by the measured friction coefficient between aircraft tire and coating. To compare regression accuracy, a grid search (GS) method and a genetic algorithm (GA) are used to optimize the relevant parameters (C , γ and \\varepsilon ), respectively. The regression accuracy could be reflected by the coefficient of determination ({{R}2} ). The result shows that the hybrid PSO-RBF-SVM-based model has better accuracy compared with the GS-RBF-SVM- and GA-RBF-SVM-based models. The agreement of this model (PSO-RBF-SVM) with experiment data confirms its good performance.

The power of timing: Adding a time-to-completion cutoff to the Word Choice Test and Recognition Memory Test improves classification accuracy.

PubMed

Erdodi, Laszlo A; Tyson, Bradley T; Shahein, Ayman G; Lichtenstein, Jonathan D; Abeare, Christopher A; Pelletier, Chantalle L; Zuccato, Brandon G; Kucharski, Brittany; Roth, Robert M

2017-05-01

The Recognition Memory Test (RMT) and Word Choice Test (WCT) are structurally similar, but psychometrically different. Previous research demonstrated that adding a time-to-completion cutoff improved the classification accuracy of the RMT. However, the contribution of WCT time-cutoffs to improve the detection of invalid responding has not been investigated. The present study was designed to evaluate the classification accuracy of time-to-completion on the WCT compared to the accuracy score and the RMT. Both tests were administered to 202 adults (M age  = 45.3 years, SD = 16.8; 54.5% female) clinically referred for neuropsychological assessment in counterbalanced order as part of a larger battery of cognitive tests. Participants obtained lower and more variable scores on the RMT (M = 44.1, SD = 7.6) than on the WCT (M = 46.9, SD = 5.7). Similarly, they took longer to complete the recognition trial on the RMT (M = 157.2 s,SD = 71.8) than the WCT (M = 137.2 s, SD = 75.7). The optimal cutoff on the RMT (≤43) produced .60 sensitivity at .87 specificity. The optimal cutoff on the WCT (≤47) produced .57 sensitivity at .87 specificity. Time-cutoffs produced comparable classification accuracies for both RMT (≥192 s; .48 sensitivity at .88 specificity) and WCT (≥171 s; .49 sensitivity at .91 specificity). They also identified an additional 6-10% of the invalid profiles missed by accuracy score cutoffs, while maintaining good specificity (.93-.95). Functional equivalence was reached at accuracy scores ≤43 (RMT) and ≤47 (WCT) or time-to-completion ≥192 s (RMT) and ≥171 s (WCT). Time-to-completion cutoffs are valuable additions to both tests. They can function as independent validity indicators or enhance the sensitivity of accuracy scores without requiring additional measures or extending standard administration time.

Geometrical accuracy of metallic objects produced with additive or subtractive manufacturing: A comparative in vitro study.

PubMed

Braian, Michael; Jönsson, David; Kevci, Mir; Wennerberg, Ann

2018-07-01

To evaluate the accuracy and precision of objects produced by additive manufacturing systems (AM) for use in dentistry and to compare with subtractive manufacturing systems (SM). Ten specimens of two geometrical objects were produced by five different AM machines and one SM machine. Object A mimics an inlay-shaped object, while object B imitates a four-unit bridge model. All the objects were sorted into different measurement dimensions (x, y, z), linear distances, angles and corner radius. None of the additive manufacturing or subtractive manufacturing groups presented a perfect match to the CAD file with regard to all parameters included in the present study. Considering linear measurements, the precision for subtractive manufacturing group was consistent in all axes for object A, presenting results of <0.050mm. The additive manufacturing groups had consistent precision in the x-axis and y-axis but not in the z-axis. With regard to corner radius measurements, the SM group had the best overall accuracy and precision for both objects A and B when compared to the AM groups. Within the limitations of this in vitro study, the conclusion can be made that subtractive manufacturing presented overall precision on all measurements below 0.050mm. The AM machines also presented fairly good precision, <0.150mm, on all axes except for the z-axis. Knowledge regarding accuracy and precision for different production techniques utilized in dentistry is of great clinical importance. The dental community has moved from casting to milling and additive techniques are now being implemented. Thus all these production techniques need to be tested, compared and validated. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Towards designing an optical-flow based colonoscopy tracking algorithm: a comparative study

NASA Astrophysics Data System (ADS)

Liu, Jianfei; Subramanian, Kalpathi R.; Yoo, Terry S.

2013-03-01

Automatic co-alignment of optical and virtual colonoscopy images can supplement traditional endoscopic procedures, by providing more complete information of clinical value to the gastroenterologist. In this work, we present a comparative analysis of our optical flow based technique for colonoscopy tracking, in relation to current state of the art methods, in terms of tracking accuracy, system stability, and computational efficiency. Our optical-flow based colonoscopy tracking algorithm starts with computing multi-scale dense and sparse optical flow fields to measure image displacements. Camera motion parameters are then determined from optical flow fields by employing a Focus of Expansion (FOE) constrained egomotion estimation scheme. We analyze the design choices involved in the three major components of our algorithm: dense optical flow, sparse optical flow, and egomotion estimation. Brox's optical flow method,1 due to its high accuracy, was used to compare and evaluate our multi-scale dense optical flow scheme. SIFT6 and Harris-affine features7 were used to assess the accuracy of the multi-scale sparse optical flow, because of their wide use in tracking applications; the FOE-constrained egomotion estimation was compared with collinear,2 image deformation10 and image derivative4 based egomotion estimation methods, to understand the stability of our tracking system. Two virtual colonoscopy (VC) image sequences were used in the study, since the exact camera parameters(for each frame) were known; dense optical flow results indicated that Brox's method was superior to multi-scale dense optical flow in estimating camera rotational velocities, but the final tracking errors were comparable, viz., 6mm vs. 8mm after the VC camera traveled 110mm. Our approach was computationally more efficient, averaging 7.2 sec. vs. 38 sec. per frame. SIFT and Harris affine features resulted in tracking errors of up to 70mm, while our sparse optical flow error was 6mm. The comparison among egomotion estimation algorithms showed that our FOE-constrained egomotion estimation method achieved the optimal balance between tracking accuracy and robustness. The comparative study demonstrated that our optical-flow based colonoscopy tracking algorithm maintains good accuracy and stability for routine use in clinical practice.

Exploring Capabilities of SENTINEL-2 for Vegetation Mapping Using Random Forest

NASA Astrophysics Data System (ADS)

Saini, R.; Ghosh, S. K.

2018-04-01

Accurate vegetation mapping is essential for monitoring crop and sustainable agricultural practice. This study aims to explore the capabilities of Sentinel-2 data over Landsat-8 Operational Land Imager (OLI) data for vegetation mapping. Two combination of Sentinel-2 dataset have been considered, first combination is 4-band dataset at 10m resolution which consists of NIR, R, G and B bands, while second combination is generated by stacking 4 bands having 10 m resolution along with other six sharpened bands using Gram-Schmidt algorithm. For Landsat-8 OLI dataset, six multispectral bands have been pan-sharpened to have a spatial resolution of 15 m using Gram-Schmidt algorithm. Random Forest (RF) and Maximum Likelihood classifier (MLC) have been selected for classification of images. It is found that, overall accuracy achieved by RF for 4-band, 10-band dataset of Sentinel-2 and Landsat-8 OLI are 88.38 %, 90.05 % and 86.68 % respectively. While, MLC give an overall accuracy of 85.12 %, 87.14 % and 83.56 % for 4-band, 10-band Sentinel and Landsat-8 OLI respectively. Results shown that 10-band Sentinel-2 dataset gives highest accuracy and shows a rise of 3.37 % for RF and 3.58 % for MLC compared to Landsat-8 OLI. However, all the classes show significant improvement in accuracy but a major rise in accuracy is observed for Sugarcane, Wheat and Fodder for Sentinel 10-band imagery. This study substantiates the fact that Sentinel-2 data can be utilized for mapping of vegetation with a good degree of accuracy when compared to Landsat-8 OLI specifically when objective is to map a sub class of vegetation.

EEG minimum-norm estimation compared with MEG dipole fitting in the localization of somatosensory sources at S1.

PubMed

Komssi, S; Huttunen, J; Aronen, H J; Ilmoniemi, R J

2004-03-01

Dipole models, which are frequently used in attempts to solve the electromagnetic inverse problem, require explicit a priori assumptions about the cerebral current sources. This is not the case for solutions based on minimum-norm estimates. In the present study, we evaluated the spatial accuracy of the L2 minimum-norm estimate (MNE) in realistic noise conditions by assessing its ability to localize sources of evoked responses at the primary somatosensory cortex (SI). Multichannel somatosensory evoked potentials (SEPs) and magnetic fields (SEFs) were recorded in 5 subjects while stimulating the median and ulnar nerves at the left wrist. A Tikhonov-regularized L2-MNE, constructed on a spherical surface from the SEP signals, was compared with an equivalent current dipole (ECD) solution obtained from the SEFs. Primarily tangential current sources accounted for both SEP and SEF distributions at around 20 ms (N20/N20m) and 70 ms (P70/P70m), which deflections were chosen for comparative analysis. The distances between the locations of the maximum current densities obtained from MNE and the locations of ECDs were on the average 12-13 mm for both deflections and nerves stimulated. In accordance with the somatotopical order of SI, both the MNE and ECD tended to localize median nerve activation more laterally than ulnar nerve activation for the N20/N20m deflection. Simulation experiments further indicated that, with a proper estimate of the source depth and with a good fit of the head model, the MNE can reach a mean accuracy of 5 mm in 0.2-microV root-mean-square noise. When compared with previously reported localizations based on dipole modelling of SEPs, it appears that equally accurate localization of S1 can be obtained with the MNE. MNE can be used to verify parametric source modelling results. Having a relatively good localization accuracy and requiring minimal assumptions, the MNE may be useful for the localization of poorly known activity distributions and for tracking activity changes between brain areas as a function of time.

Vertical profiles of the 3-D wind velocity retrieved from multiple wind lidars performing triple range-height-indicator scans

DOE PAGES

Debnath, Mithu; Iungo, G. Valerio; Ashton, Ryan; ...

2017-02-06

Vertical profiles of 3-D wind velocity are retrieved from triple range-height-indicator (RHI) scans performed with multiple simultaneous scanning Doppler wind lidars. This test is part of the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign carried out at the Boulder Atmospheric Observatory. The three wind velocity components are retrieved and then compared with the data acquired through various profiling wind lidars and high-frequency wind data obtained from sonic anemometers installed on a 300 m meteorological tower. The results show that the magnitude of the horizontal wind velocity and the wind direction obtained from the triple RHI scans are generally retrieved withmore » good accuracy. Furthermore, poor accuracy is obtained for the evaluation of the vertical velocity, which is mainly due to its typically smaller magnitude and to the error propagation connected with the data retrieval procedure and accuracy in the experimental setup.« less

Research on Modeling of Propeller in a Turboprop Engine

NASA Astrophysics Data System (ADS)

Huang, Jiaqin; Huang, Xianghua; Zhang, Tianhong

2015-05-01

In the simulation of engine-propeller integrated control system for a turboprop aircraft, a real-time propeller model with high-accuracy is required. A study is conducted to compare the real-time and precision performance of propeller models based on strip theory and lifting surface theory. The emphasis in modeling by strip theory is focused on three points as follows: First, FLUENT is adopted to calculate the lift and drag coefficients of the propeller. Next, a method to calculate the induced velocity which occurs in the ground rig test is presented. Finally, an approximate method is proposed to obtain the downwash angle of the propeller when the conventional algorithm has no solution. An advanced approximation of the velocities induced by helical horseshoe vortices is applied in the model based on lifting surface theory. This approximate method will reduce computing time and remain good accuracy. Comparison between the two modeling techniques shows that the model based on strip theory which owns more advantage on both real-time and high-accuracy can meet the requirement.

A MUSIC-based method for SSVEP signal processing.

PubMed

Chen, Kun; Liu, Quan; Ai, Qingsong; Zhou, Zude; Xie, Sheng Quan; Meng, Wei

2016-03-01

The research on brain computer interfaces (BCIs) has become a hotspot in recent years because it offers benefit to disabled people to communicate with the outside world. Steady state visual evoked potential (SSVEP)-based BCIs are more widely used because of higher signal to noise ratio and greater information transfer rate compared with other BCI techniques. In this paper, a multiple signal classification based method was proposed for multi-dimensional SSVEP feature extraction. 2-second data epochs from four electrodes achieved excellent accuracy rates including idle state detection. In some asynchronous mode experiments, the recognition accuracy reached up to 100%. The experimental results showed that the proposed method attained good frequency resolution. In most situations, the recognition accuracy was higher than canonical correlation analysis, which is a typical method for multi-channel SSVEP signal processing. Also, a virtual keyboard was successfully controlled by different subjects in an unshielded environment, which proved the feasibility of the proposed method for multi-dimensional SSVEP signal processing in practical applications.

An absolute photometric system at 10 and 20 microns

NASA Technical Reports Server (NTRS)

Rieke, G. H.; Lebofsky, M. J.; Low, F. J.

1985-01-01

Two new direct calibrations at 10 and 20 microns are presented in which terrestrial flux standards are referred to infrared standard stars. These measurements give both good agreement and higher accuracy when compared with previous direct calibrations. As a result, the absolute calibrations at 10 and 20 microns have now been determined with accuracies of 3 and 8 percent, respectively. A variety of absolute calibrations based on extrapolation of stellar spectra from the visible to 10 microns are reviewed. Current atmospheric models of A-type stars underestimate their fluxes by about 10 percent at 10 microns, whereas models of solar-type stars agree well with the direct calibrations. The calibration at 20 microns can probably be determined to about 5 percent by extrapolation from the more accurate result at 10 microns. The photometric system at 10 and 20 microns is updated to reflect the new absolute calibration, to base its zero point directly on the colors of A0 stars, and to improve the accuracy in the comparison of the standard stars.

Influence of non-level walking on pedometer accuracy.

PubMed

Leicht, Anthony S; Crowther, Robert G

2009-05-01

The YAMAX Digiwalker pedometer has been previously confirmed as a valid and reliable monitor during level walking, however, little is known about its accuracy during non-level walking activities or between genders. Subsequently, this study examined the influence of non-level walking and gender on pedometer accuracy. Forty-six healthy adults completed 3-min bouts of treadmill walking at their normal walking pace during 11 inclines (0-10%) while another 123 healthy adults completed walking up and down 47 stairs. During walking, participants wore a YAMAX Digiwalker SW-700 pedometer with the number of steps taken and registered by the pedometer recorded. Pedometer difference (steps registered-steps taken), net error (% of steps taken), absolute error (absolute % of steps taken) and gender were examined by repeated measures two-way ANOVA and Tukey's post hoc tests. During incline walking, pedometer accuracy indices were similar between inclines and gender except for a significantly greater step difference (-7+/-5 steps vs. 1+/-4 steps) and net error (-2.4+/-1.8% for 9% vs. 0.4+/-1.2% for 2%). Step difference and net error were significantly greater during stair descent compared to stair ascent while absolute error was significantly greater during stair ascent compared to stair descent. The current study demonstrated that the YAMAX Digiwalker SW-700 pedometer exhibited good accuracy during incline walking up to 10% while it overestimated steps taken during stair ascent/descent with greater overestimation during stair descent. Stair walking activity should be documented in field studies as the YAMAX Digiwalker SW-700 pedometer overestimates this activity type.

Accuracies of breeding values for dry matter intake using nongenotyped animals and predictor traits in different lactations.

PubMed

Manzanilla-Pech, C I V; Veerkamp, R F; de Haas, Y; Calus, M P L; Ten Napel, J

2017-11-01

Given the interest of including dry matter intake (DMI) in the breeding goal, accurate estimated breeding values (EBV) for DMI are needed, preferably for separate lactations. Due to the limited amount of records available on DMI, 2 main approaches have been suggested to compute those EBV: (1) the inclusion of predictor traits, such as fat- and protein-corrected milk (FPCM) and live weight (LW), and (2) the addition of genomic information of animals using what is called genomic prediction. Recently, several methodologies to estimate EBV utilizing genomic information (EBV) have become available. In this study, a new method known as single-step ridge-regression BLUP (SSRR-BLUP) is suggested. The SSRR-BLUP method does not have an imposed limit on the number of genotyped animals, as the commonly used methods do. The objective of this study was to estimate genetic parameters using a relatively large data set with DMI records, as well as compare the accuracies of the EBV for DMI. These accuracies were obtained using 4 different methods: BLUP (using pedigree for all animals with phenotypes), genomic BLUP (GBLUP; only for genotyped animals), single-step GBLUP (SS-GBLUP), and SSRR-BLUP (for genotyped and nongenotyped animals). Records from different lactations, with or without predictor traits (FPCM and LW), were used in the model. Accuracies of EBV for DMI (defined as the correlation between the EBV and pre-adjusted DMI phenotypes divided by the average accuracy of those phenotypes) ranged between 0.21 and 0.38 across methods and scenarios. Accuracies of EBV for DMI using BLUP were the lowest accuracies obtained across methods. Meanwhile, accuracies of EBV for DMI were similar in SS-GBLUP and SSRR-BLUP, and lower for the GBLUP method. Hence, SSRR-BLUP could be used when the number of genotyped animals is large, avoiding the construction of the inverse genomic relationship matrix. Adding information on DMI from different lactations in the reference population gave higher accuracies in comparison when only lactation 1 was included. Finally, no benefit was obtained by adding information on predictor traits to the reference population when DMI was already included. However, in the absence of DMI records, having records on FPCM and LW from different lactations is a good way to obtain EBV with a relatively good accuracy. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Bias from two analytical laboratories involved in a long-term air monitoring program measuring organic pollutants in the Arctic: a quality assurance/quality control assessment.

PubMed

Su, Yushan; Hung, Hayley; Stern, Gary; Sverko, Ed; Lao, Randy; Barresi, Enzo; Rosenberg, Bruno; Fellin, Phil; Li, Henrik; Xiao, Hang

2011-11-01

Initiated in 1992, air monitoring of organic pollutants in the Canadian Arctic provided spatial and temporal trends in support of Canada's participation in the Stockholm Convention of Persistent Organic Pollutants. The specific analytical laboratory charged with this task was changed in 2002 while field sampling protocols remained unchanged. Three rounds of intensive comparison studies were conducted in 2004, 2005, and 2008 to assess data comparability between the two laboratories. Analysis was compared for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in standards, blind samples of mixed standards and extracts of real air samples. Good measurement accuracy was achieved for both laboratories when standards were analyzed. Variation of measurement accuracy over time was found for some OCPs and PCBs in standards on a random and non-systematic manner. Relatively low accuracy in analyzing blind samples was likely related to the process of sample purification. Inter-laboratory measurement differences for standards (<30%) and samples (<70%) were generally less than or comparable to those reported in a previous inter-laboratory study with 21 participating laboratories. Regression analysis showed inconsistent data comparability between the two laboratories during the initial stages of the study. These inter-laboratory differences can complicate abilities to discern long-term trends of pollutants in a given sampling site. It is advisable to maintain long-term measurements with minimal changes in sample analysis.

Evaluation of Aution Max AX-4030 and 9UB Uriflet, 10PA Aution Sticks urine dipsticks in the automated urine test strip analysis.

PubMed

Rota, Cristina; Biondi, Marco; Trenti, Tommaso

2011-09-26

Aution Max AX-4030, a test strip analyzer recently introduced to the market, represents an upgrade of the Aution Max AX-4280 widely employed for urinalysis. This new instrument model can allocate two different test strips at the same time. In the present study the two instruments have been compared together with the usage of Uriflet 9UB and the recently produced Aution Sticks 10PA urine strips, the latter presenting an additional test area for the measurement of urinary creatinine. Imprecision and correlation between instruments and strips have been evaluated for chemical-physical parameters. Accuracy was evaluated for protein, glucose and creatinine by comparing the semi-quantitative results to those obtained by quantitative methods. The well-known interference effect of high ascorbic acid levels on urine glucose test strip determination was evaluated, ascorbic acid influence was also evaluated on protein and creatinine determination. The two instruments have demonstrated comparable performances: precision and correlation between instruments and strips, evaluated for chemical-physical parameters, were always good. Furthermore, accuracy was always very good: results of protein and glucose semi-quantitative measurements resulted to be highly correlated with those obtained by quantitative methods. Moreover, the semi-quantitative measurements of creatinine, employing Aution Sticks 10PA urine strips, were highly comparable with quantitative results. 10PA urine strips are eligible for urine creatinine determination with the possibility of correcting urinalysis results for urinary creatinine concentration, whenever necessary and calculating the protein creatinine ratio. Further studies should be carried out to evaluate effectiveness and appropriateness of the usage of creatinine semi-quantitative analysis.

Application of an efficient hybrid scheme for aeroelastic analysis of advanced propellers

NASA Technical Reports Server (NTRS)

Srivastava, R.; Sankar, N. L.; Reddy, T. S. R.; Huff, D. L.

1989-01-01

An efficient 3-D hybrid scheme is applied for solving Euler equations to analyze advanced propellers. The scheme treats the spanwise direction semi-explicitly and the other two directions implicitly, without affecting the accuracy, as compared to a fully implicit scheme. This leads to a reduction in computer time and memory requirement. The calculated power coefficients for two advanced propellers, SR3 and SR7L, and various advanced ratios showed good correlation with experiment. Spanwise distribution of elemental power coefficient and steady pressure coefficient differences also showed good agreement with experiment. A study of the effect of structural flexibility on the performance of the advanced propellers showed that structural deformation due to centrifugal and aero loading should be included for better correlation.

Use of a bubble tiltmeter as a horizontal seismometer

NASA Technical Reports Server (NTRS)

Miller, W. F.; Geller, R. J.; Stein, S.

1978-01-01

A bubble tiltmeter has been used as a horizontal seismometer. With the appropriate filters, the bubble system has good response for displacement over the passband of conventional seismometers (from about 10 Hz to 200 s), and for tilt from about 1 Hz to DC. The accuracy of the response is confirmed by comparing the filtered bubble output to conventional seismic instruments. The agreement between the filtered bubble records and broad band and short period conventional records is extremely good in every case. The small size, broad-band response, and lack of moving parts make the bubble ideal as an instrument for remote environments. In particular, the instrument seems ideal for the ocean bottom, land and marine boreholes and planetary missions.

A new OLED SPICE model for pixel circuit simulation in OLED-on-silicon microdisplay design

NASA Astrophysics Data System (ADS)

Bohua, Zhao; Ran, Huang; Jianhui, Bu; Yinxue, Lü; Yiqi, Wang; Fei, Ma; Guohua, Xie; Zhensong, Zhang; Huan, Du; Jiajun, Luo; Zhengsheng, Han; Yi, Zhao

2012-07-01

A new equivalent circuit model of organic-light-emitting-diode (OLED) is proposed. As the single-diode model is able to approximate OLED behavior as well as the multiple-diode model, the new model will be built based on it. In order to make sure that the experimental and simulated data are in good agreement, the constant resistor is exchanged for an exponential resistor in the new model. Compared with the measured data and the results of the other two OLED SPICE models, the simulated I—V characteristics of the new model match the measured data much better. This new model can be directly incorporated into an SPICE circuit simulator and presents good accuracy over the whole operating voltage.

A systematic evaluation of prevalence and diagnostic accuracy of sacroiliac joint interventions.

PubMed

Simopoulos, Thomas T; Manchikanti, Laxmaiah; Singh, Vijay; Gupta, Sanjeeva; Hameed, Haroon; Diwan, Sudhir; Cohen, Steven P

2012-01-01

The contributions of the sacroiliac joint to low back and lower extremity pain have been a subject of considerable debate and research. It is generally accepted that 10% to 25% of patients with persistent mechanical low back pain below L5 have pain secondary to sacroiliac joint pathology. However, no single historical, physical exam, or radiological feature can definitively establish a diagnosis of sacroiliac joint pain. Based on present knowledge, a proper diagnosis can only be made using controlled diagnostic blocks. The diagnosis and treatment of sacroiliac joint pain continue to be characterized by wide variability and a paucity of the literature. To evaluate the accuracy of diagnostic sacroiliac joint interventions. A systematic review of diagnostic sacroiliac joint interventions. Methodological quality assessment of included studies was performed using Quality Appraisal of Reliability Studies (QAREL). Only diagnostic accuracy studies meeting at least 50% of the designated inclusion criteria were utilized for analysis. Studies scoring less than 50% are presented descriptively and analyzed critically. The level of evidence was classified as good, fair, or poor based on the quality of evidence developed by the United States Preventive Services Task Force (USPSTF). Data sources included relevant literature identified through searches of PubMed and EMBASE from 1966 to December 2011, and manual searches of the bibliographies of known primary and review articles. In this evaluation we utilized controlled local anesthetic blocks using at least 50% pain relief as the reference standard. The evidence is good for the diagnosis of sacroiliac joint pain utilizing controlled comparative local anesthetic blocks. The prevalence of sacroiliac joint pain is estimated to range between 10% and 62% based on the setting; however, the majority of analyzed studies suggest a point prevalence of around 25%, with a false-positive rate for uncontrolled blocks of approximately 20%. The evidence for provocative testing to diagnose sacroiliac joint pain was fair. The evidence for the diagnostic accuracy of imaging is limited. The limitations of this systematic review include a paucity of literature, variations in technique, and variable criterion standards for the diagnosis of sacroiliac joint pain. Based on this systematic review, the evidence for the diagnostic accuracy of sacroiliac joint injections is good, the evidence for provocation maneuvers is fair, and evidence for imaging is limited.

Simulation of heat and mass transfer in turbulent channel flow using the spectral-element method: effect of spatial resolution

NASA Astrophysics Data System (ADS)

Ryzhenkov, V.; Ivashchenko, V.; Vinuesa, R.; Mullyadzhanov, R.

2016-10-01

We use the open-source code nek5000 to assess the accuracy of high-order spectral element large-eddy simulations (LES) of a turbulent channel flow depending on the spatial resolution compared to the direct numerical simulation (DNS). The Reynolds number Re = 6800 is considered based on the bulk velocity and half-width of the channel. The filtered governing equations are closed with the dynamic Smagorinsky model for subgrid stresses and heat flux. The results show very good agreement between LES and DNS for time-averaged velocity and temperature profiles and their fluctuations. Even the coarse LES grid which contains around 30 times less points than the DNS one provided predictions of the friction velocity within 2.0% accuracy interval.

Spatial accuracy of a simplified disaggregation method for traffic emissions applied in seven mid-sized Chilean cities

NASA Astrophysics Data System (ADS)

Ossés de Eicker, Margarita; Zah, Rainer; Triviño, Rubén; Hurni, Hans

The spatial accuracy of top-down traffic emission inventory maps obtained with a simplified disaggregation method based on street density was assessed in seven mid-sized Chilean cities. Each top-down emission inventory map was compared against a reference, namely a more accurate bottom-up emission inventory map from the same study area. The comparison was carried out using a combination of numerical indicators and visual interpretation. Statistically significant differences were found between the seven cities with regard to the spatial accuracy of their top-down emission inventory maps. In compact cities with a simple street network and a single center, a good accuracy of the spatial distribution of emissions was achieved with correlation values>0.8 with respect to the bottom-up emission inventory of reference. In contrast, the simplified disaggregation method is not suitable for complex cities consisting of interconnected nuclei, resulting in correlation values<0.5. Although top-down disaggregation of traffic emissions generally exhibits low accuracy, the accuracy is significantly higher in compact cities and might be further improved by applying a correction factor for the city center. Therefore, the method can be used by local environmental authorities in cities with limited resources and with little knowledge on the pollution situation to get an overview on the spatial distribution of the emissions generated by traffic activities.

Application of Hyperspectral Imaging to Detect Sclerotinia sclerotiorum on Oilseed Rape Stems

PubMed Central

Kong, Wenwen; Zhang, Chu; Huang, Weihao

2018-01-01

Hyperspectral imaging covering the spectral range of 384–1034 nm combined with chemometric methods was used to detect Sclerotinia sclerotiorum (SS) on oilseed rape stems by two sample sets (60 healthy and 60 infected stems for each set). Second derivative spectra and PCA loadings were used to select the optimal wavelengths. Discriminant models were built and compared to detect SS on oilseed rape stems, including partial least squares-discriminant analysis, radial basis function neural network, support vector machine and extreme learning machine. The discriminant models using full spectra and optimal wavelengths showed good performance with classification accuracies of over 80% for the calibration and prediction set. Comparing all developed models, the optimal classification accuracies of the calibration and prediction set were over 90%. The similarity of selected optimal wavelengths also indicated the feasibility of using hyperspectral imaging to detect SS on oilseed rape stems. The results indicated that hyperspectral imaging could be used as a fast, non-destructive and reliable technique to detect plant diseases on stems. PMID:29300315

Kannada character recognition system using neural network

NASA Astrophysics Data System (ADS)

Kumar, Suresh D. S.; Kamalapuram, Srinivasa K.; Kumar, Ajay B. R.

2013-03-01

Handwriting recognition has been one of the active and challenging research areas in the field of pattern recognition. It has numerous applications which include, reading aid for blind, bank cheques and conversion of any hand written document into structural text form. As there is no sufficient number of works on Indian language character recognition especially Kannada script among 15 major scripts in India. In this paper an attempt is made to recognize handwritten Kannada characters using Feed Forward neural networks. A handwritten Kannada character is resized into 20x30 Pixel. The resized character is used for training the neural network. Once the training process is completed the same character is given as input to the neural network with different set of neurons in hidden layer and their recognition accuracy rate for different Kannada characters has been calculated and compared. The results show that the proposed system yields good recognition accuracy rates comparable to that of other handwritten character recognition systems.

Comparison of Regression Analysis and Transfer Function in Estimating the Parameters of Central Pulse Waves from Brachial Pulse Wave.

PubMed

Chai, Rui; Xu, Li-Sheng; Yao, Yang; Hao, Li-Ling; Qi, Lin

2017-01-01

This study analyzed ascending branch slope (A_slope), dicrotic notch height (Hn), diastolic area (Ad) and systolic area (As) diastolic blood pressure (DBP), systolic blood pressure (SBP), pulse pressure (PP), subendocardial viability ratio (SEVR), waveform parameter (k), stroke volume (SV), cardiac output (CO), and peripheral resistance (RS) of central pulse wave invasively and non-invasively measured. Invasively measured parameters were compared with parameters measured from brachial pulse waves by regression model and transfer function model. Accuracy of parameters estimated by regression and transfer function model, was compared too. Findings showed that k value, central pulse wave and brachial pulse wave parameters invasively measured, correlated positively. Regression model parameters including A_slope, DBP, SEVR, and transfer function model parameters had good consistency with parameters invasively measured. They had same effect of consistency. SBP, PP, SV, and CO could be calculated through the regression model, but their accuracies were worse than that of transfer function model.

The strategic management of organizational knowledge exchange related to hospital quality measurement and reporting.

PubMed

Rangachari, Pavani

2008-01-01

CONTEXT/PURPOSE: With the growing momentum toward hospital quality measurement and reporting by public and private health care payers, hospitals face increasing pressures to improve their medical record documentation and administrative data coding accuracy. This study explores the relationship between the organizational knowledge-sharing structure related to quality and hospital coding accuracy for quality measurement. Simultaneously, this study seeks to identify other leadership/management characteristics associated with coding for quality measurement. Drawing upon complexity theory, the literature on "professional complex systems" has put forth various strategies for managing change and turnaround in professional organizations. In so doing, it has emphasized the importance of knowledge creation and organizational learning through interdisciplinary networks. This study integrates complexity, network structure, and "subgoals" theories to develop a framework for knowledge-sharing network effectiveness in professional complex systems. This framework is used to design an exploratory and comparative research study. The sample consists of 4 hospitals, 2 showing "good coding" accuracy for quality measurement and 2 showing "poor coding" accuracy. Interviews and surveys are conducted with administrators and staff in the quality, medical staff, and coding subgroups in each facility. Findings of this study indicate that good coding performance is systematically associated with a knowledge-sharing network structure rich in brokerage and hierarchy (with leaders connecting different professional subgroups to each other and to the external environment), rather than in density (where everyone is directly connected to everyone else). It also implies that for the hospital organization to adapt to the changing environment of quality transparency, senior leaders must undertake proactive and unceasing efforts to coordinate knowledge exchange across physician and coding subgroups and connect these subgroups with the changing external environment.

Modeling additive and non-additive effects in a hybrid population using genome-wide genotyping: prediction accuracy implications

PubMed Central

Bouvet, J-M; Makouanzi, G; Cros, D; Vigneron, Ph

2016-01-01

Hybrids are broadly used in plant breeding and accurate estimation of variance components is crucial for optimizing genetic gain. Genome-wide information may be used to explore models designed to assess the extent of additive and non-additive variance and test their prediction accuracy for the genomic selection. Ten linear mixed models, involving pedigree- and marker-based relationship matrices among parents, were developed to estimate additive (A), dominance (D) and epistatic (AA, AD and DD) effects. Five complementary models, involving the gametic phase to estimate marker-based relationships among hybrid progenies, were developed to assess the same effects. The models were compared using tree height and 3303 single-nucleotide polymorphism markers from 1130 cloned individuals obtained via controlled crosses of 13 Eucalyptus urophylla females with 9 Eucalyptus grandis males. Akaike information criterion (AIC), variance ratios, asymptotic correlation matrices of estimates, goodness-of-fit, prediction accuracy and mean square error (MSE) were used for the comparisons. The variance components and variance ratios differed according to the model. Models with a parent marker-based relationship matrix performed better than those that were pedigree-based, that is, an absence of singularities, lower AIC, higher goodness-of-fit and accuracy and smaller MSE. However, AD and DD variances were estimated with high s.es. Using the same criteria, progeny gametic phase-based models performed better in fitting the observations and predicting genetic values. However, DD variance could not be separated from the dominance variance and null estimates were obtained for AA and AD effects. This study highlighted the advantages of progeny models using genome-wide information. PMID:26328760

Quality of information on the internet related to bladder pain syndrome: a systematic review of the evidence.

PubMed

Tirlapur, S A; Leiu, C; Khan, K S

2013-08-01

Bladder pain syndrome (BPS) has an impact on quality of life and available treatments often only provide temporary symptomatic relief. The information provided by websites can be valuable for patient education and management. The hypothesis was to assess medical information available on the internet related to bladder pain syndrome in terms of accuracy, credibility, readability and quality. A search was performed in the meta-search engine Copernic Agent, using the search terms "bladder pain syndrome, interstitial cystitis, painful bladder syndrome and pelvic pain", which simultaneously captured websites from a range of engines. Websites in the English language that were open-access were included. The four quality assessments used were: credibility using a ten-point scale, accuracy based on the American Urological Association guidelines, quality using the DISCERN questionnaire and readability using the Flesch Reading Ease Score. Inter-rater agreement was tested by intra-class coefficient (ICC). Eighteen suitable websites were identified; 7 (39%) were specialist or specific to BPS. The combined mean scores for accuracy, quality, credibility and readability ranged from 83 to 144 for specialist websites and 76 to 137 for non-specialist ones, with a maximum possible score of 208. There was good inter-observer agreement for the assessments performed with an ICC ranging from 0.80 for DISCERN to 0.53 for readability. Specialist websites had higher quality scores (median difference 10, p = 0.07) and readability scores (median difference 5.4, p = 0.05) compared with non-specialist websites whereas credibility and accuracy scores were no different. We found four websites that fulfilled our criteria for good quality information.

Feasibility of MDCT angiography for determination of tumor-feeding vessels in chemoembolization of hepatocellular carcinoma.

PubMed

Kim, Inwha; Kim, Dae Jung; Kim, Kyoung Ah; Yoon, Sang Wook; Lee, Jong Tae

2014-01-01

To investigate the feasibility and accuracy of multidetector computed tomography (MDCT) angiography for assessment of subsegmental tumor-feeding vessels in transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). A total of 23 patients with 36 HCCs who underwent TACE during a 14-month period were enrolled. All patients underwent 3-phase dynamic MDCT within a month before TACE. Arterial phase MDCT images were retrospectively reformatted and analyzed for determination of single subsegmental tumor-feeding vessel using maximum intensity projection (MIP) and volume-rendering technique (VRT). Two radiologists independently assessed and scored the MIP and VRT images using 4-grade visual scores (grade 1, no depiction of tumor-feeding vessel; grade 2, indeterminate tumor-feeding vessel; grade 3, probable tumor-feeding vessel; and grade 4, good depiction of tumor-feeding vessel). The weighted kappa test was used to determine interobserver variability, and Wilcoxon signed rank test was used to differentiate visual scores of each technique. Results of digital subtraction angiography were defined as the criterion standard; therefore, assessment of subsegmental tumor-feeding vessel using MIP or VRT was compared with digital subtraction angiography, and the accuracy of each technique was calculated. Interobserver agreement (weighted kappa, 0.746 on VRT and 0.806 on MIP) was substantial to almost perfect. The visual scores for MIP (mean, 3.64 for reviewer 1 and 3.5 for reviewer 2) were higher than those for VRT (mean, 2.11 for reviewer 1 and 2.22 for reviewer 2; P = 0.000). The accuracy for assessing subsegmental tumor-feeding vessel was 22.2% for VRT and 77.8% for MIP. Multidetector CT angiography using MIP showed good imaging quality and high accuracy for determination of subsegmental tumor-feeding vessels.

Story Goodness in Adolescents with Autism Spectrum Disorder (ASD) and in Optimal Outcomes from ASD

ERIC Educational Resources Information Center

Canfield, Allison R.; Eigsti, Inge-Marie; de Marchena, Ashley; Fein, Deborah

2016-01-01

Purpose: This study examined narrative quality of adolescents with autism spectrum disorder (ASD) using a well-studied "story goodness" coding system. Method: Narrative samples were analyzed for distinct aspects of story goodness and rated by naïve readers on dimensions of story goodness, accuracy, cohesiveness, and oddness. Adolescents…

Adaptation and application of multivariate AMBI (M-AMBI) in US coastal waters.

PubMed

Pelletier, Marguerite C; Gillett, David J; Hamilton, Anna; Grayson, Treda; Hansen, Virginia; Leppo, Erik W; Weisberg, Stephan B; Borja, Angel

2018-06-01

The multivariate AMBI (M-AMBI) is an extension of the AZTI Marine Biotic Index (AMBI) that has been used extensively in Europe, but not in the United States. In a previous study, we adapted AMBI for use in US coastal waters (US AMBI), but saw biases in salinity and score distribution when compared to locally calibrated indices. In this study we modified M-AMBI for US waters and compared its performance to that of US AMBI. Index performance was evaluated in three ways: 1) concordance with local indices presently being used as management tools in three geographic regions of US coastal waters, 2) classification accuracy for sites defined a priori as good or bad and 3) insensitivity to natural environmental gradients. US M-AMBI was highly correlated with all three local indices and removed the compression in response seen in moderately disturbed sites with US AMBI. US M-AMBI and US AMBI did a similar job correctly classifying sites as good or bad in local validation datasets (83 to 100% accuracy vs. 84 to 95%, respectively). US M-AMBI also removed the salinity bias of US AMBI so that lower salinity sites were not more likely to be incorrectly classified as impaired. The US M-AMBI appears to be an acceptable index for comparing condition across broad-scales such as estuarine and coastal waters surveyed by the US EPA's National Coastal Condition Assessment, and may be applicable to areas of the US coast that do not have a locally derived benthic index.

Experimental evaluation criteria for constitutive models of time dependent cyclic plasticity

NASA Technical Reports Server (NTRS)

Martin, J. F.

1986-01-01

Notched members were tested at temperatures far above those recorded till now. Simulation of the notch root stress response was accomplished to establish notch stress-strain behavior. Cyclic stress-strain profiles across the net-section were recorded and on-line direct notch strain control was accomplished. Data are compared to three analysis techniques with good results. The objective of the study is to generate experimental data that can be used to evaluate the accuracy of constitutive models of time dependent cyclic plasticity.

Neutron spectroscopy of magnesium dihydride

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

Kolesnikov, Alexander I; Antonov, Vladimir E.; Efimchenko, V. S.

2011-01-01

Inelastic neutron scattering spectra of -MgH2 powder have been measured at T = 7 K with an energy resolution better than 1.5% using the time-of-flight direct geometry spectrometer SEQUOIA. Based on these spectra, the density g(E) of phonon states in -MgH2 has been experimentally constructed for the fist time. Comparing the available experimental data on the heat capacity of -MgH2 with those calculated using the obtained g(E) spectrum confirmed the good accuracy of its determination.

Closed-Form Evaluation of Mutual Coupling in a Planar Array of Circular Apertures

NASA Technical Reports Server (NTRS)

Bailey, M. C.

1996-01-01

The integral expression for the mutual admittance between circular apertures in a planar array is evaluated in closed form. Very good accuracy is realized when compared with values that were obtained by numerical integration. Utilization of this closed-form expression, for all element pairs that are separated by more than one element spacing, yields extremely accurate results and significantly reduces the computation time that is required to analyze the performance of a large electronically scanning antenna array.

High-pressure liquid chromatography analysis of antibiotic susceptibility disks.

PubMed Central

Hagel, R B; Waysek, E H; Cort, W M

1979-01-01

The analysis of antibiotic susceptibility disks by high-pressure liquid chromatography (HPLC) was investigated. Methods are presented for the potency determination of mecillinam, ampicillin, carbenicillin, and cephalothin alone and in various combinations. Good agreement between HPLC and microbiological data is observed for potency determinations with recoveries of greater than 95%. Relative standard deviations of lower than 2% are recorded for each HPLC method. HPLC methods offer improved accuracy and greater precision when compared to the standard microbiological methods of analysis for susceptibility disks. PMID:507793

The relative trending accuracy of noninvasive continuous hemoglobin monitoring during hemodialysis in critically ill patients.

PubMed

Yamada, Hiroshi; Saeki, Minako; Ito, Junko; Kawada, Kazuhiro; Higurashi, Aya; Funakoshi, Hiromi; Takeda, Kohji

2015-02-01

The pulse CO-Oximeter (Radical-7; Masimo Corp., Irvine, CA) is a multi-wavelength spectrophotometric method for noninvasive continuous monitoring of hemoglobin (SpHb). Because evaluating the relative change in blood volume (ΔBV) is crucial to avoid hypovolemia and hypotension during hemodialysis, it would be of great clinical benefit if ΔBV could be estimated by measurement of SpHb during hemodialysis. The capability of the pulse CO-Oximeter to monitor ΔBV depends on the relative trending accuracy of SpHb. The purpose of the current study was to evaluate the relative trending accuracy of SpHb by the pulse CO-Oximeter using Crit-Line as a reference device. In 12 patients who received hemodialysis (total 22 sessions) in the intensive care unit, ΔBV was determined from SpHb. Relative changes in blood volume determined from SpHb were calculated according to the equation: ΔBV(SpHb)=[starting SpHb]/[current SpHb] - 1. The absolute values of SpHb and hematocrit measured by Crit-Line (CL-Hct) showed poor correlation. On the contrary, linear regression analysis showed good correlation between ΔBV(SpHb) and the relative change in blood volume measured by Crit-Line [ΔBV(CL-Hct)] (r=0.83; P≤0.001). Bland-Altman analysis also revealed good agreement between ΔBV(SpHb) and ΔBV(CL-Hct) (bias, -0.77%; precision, 3.41%). Polar plot analysis revealed good relative trending accuracy of SpHb with an angular bias of 4.1° and radial limits of agreement of 24.4° (upper) and -16.2° (lower). The results of the current study indicate that SpHb measurement with the pulse CO-Oximeter has good relative trending accuracy.

Assessment of leaf carotenoids content with a new carotenoid index: Development and validation on experimental and model data

NASA Astrophysics Data System (ADS)

Zhou, Xianfeng; Huang, Wenjiang; Kong, Weiping; Ye, Huichun; Dong, Yingying; Casa, Raffaele

2017-05-01

Leaf carotenoids content (LCar) is an important indicator of plant physiological status. Accurate estimation of LCar provides valuable insight into early detection of stress in vegetation. With spectroscopy techniques, a semi-empirical approach based on spectral indices was extensively used for carotenoids content estimation. However, established spectral indices for carotenoids that generally rely on limited measured data, might lack predictive accuracy for carotenoids estimation in various species and at different growth stages. In this study, we propose a new carotenoid index (CARI) for LCar assessment based on a large synthetic dataset simulated from the leaf radiative transfer model PROSPECT-5, and evaluate its capability with both simulated data from PROSPECT-5 and 4SAIL and extensive experimental datasets: the ANGERS dataset and experimental data acquired in field experiments in China in 2004. Results show that CARI was the index most linearly correlated with carotenoids content at the leaf level using a synthetic dataset (R2 = 0.943, RMSE = 1.196 μg/cm2), compared with published spectral indices. Cross-validation results with CARI using ANGERS data achieved quite an accurate estimation (R2 = 0.545, RMSE = 3.413 μg/cm2), though the RBRI performed as the best index (R2 = 0.727, RMSE = 2.640 μg/cm2). CARI also showed good accuracy (R2 = 0.639, RMSE = 1.520 μg/cm2) for LCar assessment with leaf level field survey data, though PRI performed better (R2 = 0.710, RMSE = 1.369 μg/cm2). Whereas RBRI, PRI and other assessed spectral indices showed a good performance for a given dataset, overall their estimation accuracy was not consistent across all datasets used in this study. Conversely CARI was more robust showing good results in all datasets. Further assessment of LCar with simulated and measured canopy reflectance data indicated that CARI might not be very sensitive to LCar changes at low leaf area index (LAI) value, and in these conditions soil moisture influenced the LCar retrieval accuracy.

Superior accuracy of model-based radiostereometric analysis for measurement of polyethylene wear

PubMed Central

Stilling, M.; Kold, S.; de Raedt, S.; Andersen, N. T.; Rahbek, O.; Søballe, K.

2012-01-01

Objectives The accuracy and precision of two new methods of model-based radiostereometric analysis (RSA) were hypothesised to be superior to a plain radiograph method in the assessment of polyethylene (PE) wear. Methods A phantom device was constructed to simulate three-dimensional (3D) PE wear. Images were obtained consecutively for each simulated wear position for each modality. Three commercially available packages were evaluated: model-based RSA using laser-scanned cup models (MB-RSA), model-based RSA using computer-generated elementary geometrical shape models (EGS-RSA), and PolyWare. Precision (95% repeatability limits) and accuracy (Root Mean Square Errors) for two-dimensional (2D) and 3D wear measurements were assessed. Results The precision for 2D wear measures was 0.078 mm, 0.102 mm, and 0.076 mm for EGS-RSA, MB-RSA, and PolyWare, respectively. For the 3D wear measures the precision was 0.185 mm, 0.189 mm, and 0.244 mm for EGS-RSA, MB-RSA, and PolyWare respectively. Repeatability was similar for all methods within the same dimension, when compared between 2D and 3D (all p > 0.28). For the 2D RSA methods, accuracy was below 0.055 mm and at least 0.335 mm for PolyWare. For 3D measurements, accuracy was 0.1 mm, 0.2 mm, and 0.3 mm for EGS-RSA, MB-RSA and PolyWare respectively. PolyWare was less accurate compared with RSA methods (p = 0.036). No difference was observed between the RSA methods (p = 0.10). Conclusions For all methods, precision and accuracy were better in 2D, with RSA methods being superior in accuracy. Although less accurate and precise, 3D RSA defines the clinically relevant wear pattern (multidirectional). PolyWare is a good and low-cost alternative to RSA, despite being less accurate and requiring a larger sample size. PMID:23610688

Effect of fluoroscopic X-ray beam spectrum on air-kerma measurement accuracy: implications for establishing correction coefficients on interventional fluoroscopes with KAP meters.

PubMed

Wunderle, Kevin A; Rakowski, Joseph T; Dong, Frank F

2016-05-08

The first goal of this study was to investigate the accuracy of the displayed reference plane air kerma (Ka,r) or air kerma-area product (Pk,a) over a broad spectrum of X-ray beam qualities on clinically used interventional fluoroscopes incorporating air kerma-area product meters (KAP meters) to measure X-ray output. The second goal was to investigate the accuracy of a correction coefficient (CC) determined at a single beam quality and applied to the measured Ka,r over a broad spectrum of beam qualities. Eleven state-of-the-art interventional fluoroscopes were evaluated, consisting of eight Siemens Artis zee and Artis Q systems and three Philips Allura FD systems. A separate calibrated 60 cc ionization chamber (external chamber) was used to determine the accuracy of the KAP meter over a broad range of clinically used beam qualities. For typical adult beam qualities, applying a single CC deter-mined at 100 kVp with copper (Cu) in the beam resulted in a deviation of < 5% due to beam quality variation. This result indicates that applying a CC determined using The American Association of Physicists in Medicine Task Group 190 protocol or a similar protocol provides very good accuracy as compared to the allowed ± 35% deviation of the KAP meter in this limited beam quality range. For interventional fluoroscopes dedicated to or routinely used to perform pediatric interventions, using a CC established with a low kVp (~ 55-60 kVp) and large amount of Cu filtration (~ 0.6-0.9 mm) may result in greater accuracy as compared to using the 100 kVp values. KAP meter responses indicate that fluoroscope vendors are likely normalizing or otherwise influencing the KAP meter output data. Although this may provide improved accuracy in some instances, there is the potential for large discrete errors to occur, and these errors may be difficult to identify.

Interference with activities due to pain and fatigue: Accuracy of ratings across different reporting periods

PubMed Central

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

2010-01-01

Purpose This study examined the impact of different reporting period lengths on the accuracy of items measuring interference due to pain and fatigue with work, walking, and relations with others. Methods Six items from well-established instruments (Brief Pain Inventory, Brief Fatigue Inventory, SF-36) were investigated in a prospective study of 117 patients with chronic rheumatological illness. Daily ratings were compared with recall ratings of 1, 3, 7, and 28-day reporting periods. Results The level of recall ratings (RRs) for reporting periods of 3 days or more were significantly higher than the level of aggregated end-of-day (EOD) ratings. Correspondence between aggregated EOD and RRs was good (r ≥ .80) regardless of the length of the reporting period. Ratings of interference for a single day were highly correlated with aggregated EOD for up to 14 days prior to the single rating (r ≥ .76). Conclusions Recall ratings with reporting periods of up to a month yield good correspondence with aggregated daily ratings, although the absolute level of the rating will be inflated for recall periods of 3 days or longer. PMID:20535565

Effect of sample preparation method on quantification of polymorphs using PXRD.

PubMed

Alam, Shahnwaz; Patel, Sarsvatkumar; Bansal, Arvind Kumar

2010-01-01

The purpose of this study was to improve the sensitivity and accuracy of quantitative analysis of polymorphic mixtures. Various techniques such as hand grinding and mixing (in mortar and pestle), air jet milling and ball milling for micronization of particle and mixing were used to prepare binary mixtures. Using these techniques, mixtures of form I and form II of clopidogrel bisulphate were prepared in various proportions from 0-5% w/w of form I in form II and subjected to x-ray powder diffraction analysis. In order to obtain good resolution in minimum time, step time and step size were varied to optimize scan rate. Among the six combinations, step size of 0.05 degrees with step time of 5 s demonstrated identification of maximum characteristic peaks of form I in form II. Data obtained from samples prepared using both grinding and mixing in ball mill showed good analytical sensitivity and accuracy compared to other methods. Powder x-ray diffraction method was reproducible, precise with LOD of 0.29% and LOQ of 0.91%. Validation results showed excellent correlation between actual and predicted concentration with R2 > 0.9999.

A pressure-affected headspace-gas chromatography method for determining calcium carbonate content in paper sample.

PubMed

Dai, Yi; Yu, Zhen-Hua; Zhan, Jian-Bo; Chai, Xin-Sheng; Zhang, Shu-Xin; Xie, Wei-Qi; He, Liang

2017-07-21

The present work reports on the development of a pressure-affected based headspace (HS) analytical technique for the determination of calcium carbonate content in paper samples. By the acidification, the carbonate in the sample was converted to CO 2 and released into the headspace of a closed vial and then measured by gas chromatography (GC). When the amount of carbonate in the sample is significant, the pressure created by the CO 2 affects the accuracy of the method. However, the pressure also causes a change in the O 2 signal in the HS-GC measurement, which is a change that can be used as an indirect measure of the carbonate in the sample. The results show that the present method has a good precision (the relative standard deviation<2.32%), and good accuracy (the relative differences compared to a reference method was<5.76%). Coupled with the fact that the method is simple, rapid, and accurate, it is suitable for a variety of applications that call for the analysis of high carbonate content in paper samples. Copyright © 2017 Elsevier B.V. All rights reserved.

A meta-analysis of the validity of FFQ targeted to adolescents.

PubMed

Tabacchi, Garden; Filippi, Anna Rita; Amodio, Emanuele; Jemni, Monèm; Bianco, Antonino; Firenze, Alberto; Mammina, Caterina

2016-05-01

The present work is aimed at meta-analysing validity studies of FFQ for adolescents, to investigate their overall accuracy and variables that can affect it negatively. A meta-analysis of sixteen original articles was performed within the ASSO Project (Adolescents and Surveillance System in the Obesity prevention). The articles assessed the validity of FFQ for adolescents, compared with food records or 24 h recalls, with regard to energy and nutrient intakes. Pearson's or Spearman's correlation coefficients, means/standard deviations, kappa agreement, percentiles and mean differences/limits of agreement (Bland-Altman method) were extracted. Pooled estimates were calculated and heterogeneity tested for correlation coefficients and means/standard deviations. A subgroup analysis assessed variables influencing FFQ accuracy. An overall fair/high correlation between FFQ and reference method was found; a good agreement, measured through the intake mean comparison for all nutrients except sugar, carotene and K, was observed. Kappa values showed fair/moderate agreement; an overall good ability to rank adolescents according to energy and nutrient intakes was evidenced by data of percentiles; absolute validity was not confirmed by mean differences/limits of agreement. Interviewer administration mode, consumption interval of the previous year/6 months and high number of food items are major contributors to heterogeneity and thus can reduce FFQ accuracy. The meta-analysis shows that FFQ are accurate tools for collecting data and could be used for ranking adolescents in terms of energy and nutrient intakes. It suggests how the design and the validation of a new FFQ should be addressed.

The Role of Pattern Goodness in the Reproduction of Backward Masked Patterns

ERIC Educational Resources Information Center

Bell, Herbert H.; Handel, Stephen

1976-01-01

The purpose of the present work was to investigate the relation between pattern goodness and accuracy of reproduction in backward masking. It may be hypothesized that good patterns, being easier to encode as wholes, will be reproduced more easily than poorer patterns. Four experiments were performed. (Author)

Uniform Sampling Table Method and its Applications II--Evaluating the Uniform Sampling by Experiment.

PubMed

Chen, Yibin; Chen, Jiaxi; Chen, Xuan; Wang, Min; Wang, Wei

2015-01-01

A new method of uniform sampling is evaluated in this paper. The items and indexes were adopted to evaluate the rationality of the uniform sampling. The evaluation items included convenience of operation, uniformity of sampling site distribution, and accuracy and precision of measured results. The evaluation indexes included operational complexity, occupation rate of sampling site in a row and column, relative accuracy of pill weight, and relative deviation of pill weight. They were obtained from three kinds of drugs with different shape and size by four kinds of sampling methods. Gray correlation analysis was adopted to make the comprehensive evaluation by comparing it with the standard method. The experimental results showed that the convenience of uniform sampling method was 1 (100%), odds ratio of occupation rate in a row and column was infinity, relative accuracy was 99.50-99.89%, reproducibility RSD was 0.45-0.89%, and weighted incidence degree exceeded the standard method. Hence, the uniform sampling method was easy to operate, and the selected samples were distributed uniformly. The experimental results demonstrated that the uniform sampling method has good accuracy and reproducibility, which can be put into use in drugs analysis.

Validation of cardiac accelerometer sensor measurements.

PubMed

Remme, Espen W; Hoff, Lars; Halvorsen, Per Steinar; Naerum, Edvard; Skulstad, Helge; Fleischer, Lars A; Elle, Ole Jakob; Fosse, Erik

2009-12-01

In this study we have investigated the accuracy of an accelerometer sensor designed for the measurement of cardiac motion and automatic detection of motion abnormalities caused by myocardial ischaemia. The accelerometer, attached to the left ventricular wall, changed its orientation relative to the direction of gravity during the cardiac cycle. This caused a varying gravity component in the measured acceleration signal that introduced an error in the calculation of myocardial motion. Circumferential displacement, velocity and rotation of the left ventricular apical region were calculated from the measured acceleration signal. We developed a mathematical method to separate translational and gravitational acceleration components based on a priori assumptions of myocardial motion. The accuracy of the measured motion was investigated by comparison with known motion of a robot arm programmed to move like the heart wall. The accuracy was also investigated in an animal study. The sensor measurements were compared with simultaneously recorded motion from a robot arm attached next to the sensor on the heart and with measured motion by echocardiography and a video camera. The developed compensation method for the varying gravity component improved the accuracy of the calculated velocity and displacement traces, giving very good agreement with the reference methods.

EVALUATION OF DIAGNOSTIC ACCURACY OF THE COMPARATIVE TUBERCULIN SKIN TEST IN REHABILITANT BORNEAN ORANGUTANS (PONGO PYGMAEUS).

PubMed

Dench, Rosalie; Sulistyo, Fransiska; Fahroni, Agus; Philippa, Joost

2015-12-01

The tuberculin skin test (TST) has been the mainstay of tuberculosis (TB) testing in primates for decades, but its interpretation in orangutans (Pongo spp.) is challenging, because many animals react strongly, without evidence of infection with Mycobacterium tuberculosis complex. One explanation is cross-reactivity with environmental nontuberculous mycobacteria (NTM). The use of a comparative TST (CTST), comparing reactivity to avian (representing NTM) and bovine (representing tuberculous mycobacteria) tuberculins aids in distinguishing cross-reactivity due to sensitization by NTM from shared antigens. The specificity of the TST can be increased with the use of CTST. We considered three interpretations of the TST in rehabilitant Bornean orangutans ( Pongo pygmaeus ) using avian purified protein derivative (APPD; 25,000 IU/ml) and two concentrations of bovine purified protein derivative (BPPD; 100,000 and 32,500 IU/ml). The tests were evaluated for their ability to identify accurately seven orangutans previously diagnosed with and treated for TB from a group of presumed negative individuals (n = 288 and n = 161 for the two respective BPPD concentrations). BPPD at 32,500 IU/ml had poor diagnostic capacity, whereas BPPD at 100,000 IU/ml performed better. The BPPD-only interpretation had moderate sensitivity (57%) and poor specificity (40%) and accuracy (41%). The comparative interpretation at 72 hr had similar sensitivity (57%) but improved specificity (95%) and accuracy (94%). However, best results were obtained by a comparative interpretation incorporating the 48- and 72-hr scores, which had good sensitivity (86%), specificity (95%) and accuracy (95%). These data reinforce recommendations that a CTST be used in orangutans and support the use of APPD at 25,000 IU/ml and BPPD at 100,000 IU/ml. The highest score at each site from the 48- and 72-hr checks should be considered the result for that tuberculin. If the bovine result is greater than the avian result, the animal should be considered a TB suspect.

Benchmark for Peak Detection Algorithms in Fiber Bragg Grating Interrogation and a New Neural Network for its Performance Improvement

PubMed Central

Negri, Lucas; Nied, Ademir; Kalinowski, Hypolito; Paterno, Aleksander

2011-01-01

This paper presents a benchmark for peak detection algorithms employed in fiber Bragg grating spectrometric interrogation systems. The accuracy, precision, and computational performance of currently used algorithms and those of a new proposed artificial neural network algorithm are compared. Centroid and gaussian fitting algorithms are shown to have the highest precision but produce systematic errors that depend on the FBG refractive index modulation profile. The proposed neural network displays relatively good precision with reduced systematic errors and improved computational performance when compared to other networks. Additionally, suitable algorithms may be chosen with the general guidelines presented. PMID:22163806

The accuracy and consistency of rural, remote and outpost triage nurse decision making in one Western Australia Country Health Service Region.

PubMed

Ekins, Kylie; Morphet, Julia

2015-11-01

The Australasian Triage Scale aims to ensure that the triage category allocated, reflects the urgency with which the patient needs medical assistance. This is dependent on triage nurse accuracy in decision making. The Australasian Triage Scale also aims to facilitate triage decision consistency between individuals and organisations. Various studies have explored the accuracy and consistency of triage decisions throughout Australia, yet no studies have specifically focussed on triage decision making in rural health services. Further, no standard has been identified by which accuracy or consistency should be measured. Australian emergency departments are measured against a set of standard performance indicators, including time from triage to patient review, and patient length of stay. There are currently no performance indicators for triage consistency. An online questionnaire was developed to collect demographic data and measure triage accuracy and consistency. The questionnaire utilised previously validated triage scenarios.(1) Triage decision accuracy was measured, and consistency was compared by health site type using Fleiss' kappa. Forty-six triage nurses participated in this study. The accuracy of participants' triage decision-making decreased with each less urgent triage category. Post-graduate qualifications had no bearing on triage accuracy. There was no significant difference in the consistency of decision-making between paediatric and adult scenarios. Overall inter-rater agreement using Fleiss' kappa coefficient, was 0.4. This represents a fair-to-good level of inter-rater agreement. A standard definition of accuracy and consistency in triage nurse decision making is required. Inaccurate triage decisions can result in increased morbidity and mortality. It is recommended that emergency department performance indicator thresholds be utilised as a benchmark for national triage consistency. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

An experimental comparison of ETM+ image geometric correction methods in the mountainous areas of Yunnan Province, China

NASA Astrophysics Data System (ADS)

Wang, Jinliang; Wu, Xuejiao

2010-11-01

Geometric correction of imagery is a basic application of remote sensing technology. Its precision will impact directly on the accuracy and reliability of applications. The accuracy of geometric correction depends on many factors, including the used model for correction and the accuracy of the reference map, the number of ground control points (GCP) and its spatial distribution, resampling methods. The ETM+ image of Kunming Dianchi Lake Basin and 1:50000 geographical maps had been used to compare different correction methods. The results showed that: (1) The correction errors were more than one pixel and some of them were several pixels when the polynomial model was used. The correction accuracy was not stable when the Delaunay model was used. The correction errors were less than one pixel when the collinearity equation was used. (2) 6, 9, 25 and 35 GCP were selected randomly for geometric correction using the polynomial correction model respectively, the best result was obtained when 25 GCPs were used. (3) The contrast ratio of image corrected by using nearest neighbor and the best resampling rate was compared to that of using the cubic convolution and bilinear model. But the continuity of pixel gravy value was not very good. The contrast of image corrected was the worst and the computation time was the longest by using the cubic convolution method. According to the above results, the result was the best by using bilinear to resample.

Prediction-Oriented Marker Selection (PROMISE): With Application to High-Dimensional Regression.

PubMed

Kim, Soyeon; Baladandayuthapani, Veerabhadran; Lee, J Jack

2017-06-01

In personalized medicine, biomarkers are used to select therapies with the highest likelihood of success based on an individual patient's biomarker/genomic profile. Two goals are to choose important biomarkers that accurately predict treatment outcomes and to cull unimportant biomarkers to reduce the cost of biological and clinical verifications. These goals are challenging due to the high dimensionality of genomic data. Variable selection methods based on penalized regression (e.g., the lasso and elastic net) have yielded promising results. However, selecting the right amount of penalization is critical to simultaneously achieving these two goals. Standard approaches based on cross-validation (CV) typically provide high prediction accuracy with high true positive rates but at the cost of too many false positives. Alternatively, stability selection (SS) controls the number of false positives, but at the cost of yielding too few true positives. To circumvent these issues, we propose prediction-oriented marker selection (PROMISE), which combines SS with CV to conflate the advantages of both methods. Our application of PROMISE with the lasso and elastic net in data analysis shows that, compared to CV, PROMISE produces sparse solutions, few false positives, and small type I + type II error, and maintains good prediction accuracy, with a marginal decrease in the true positive rates. Compared to SS, PROMISE offers better prediction accuracy and true positive rates. In summary, PROMISE can be applied in many fields to select regularization parameters when the goals are to minimize false positives and maximize prediction accuracy.

The comparison of high and standard definition computed tomography techniques regarding coronary artery imaging.

PubMed

Aykut, Aktas; Bumin, Degirmenci; Omer, Yilmaz; Mustafa, Kayan; Meltem, Cetin; Orhan, Celik; Nisa, Unlu; Hikmet, Orhan; Hakan, Demirtas; Mert, Koroglu

2015-09-01

The aim was to compare coronary high-definition CT (HDCT) with standard-definition CT (SDCT) angiography as to radiation dose, image quality and accuracy. 28 patients with history of coronary artery disease scanned by HDCT (Discovery CT750 HD) and SDCT (Somatom Definition AS). The scan modes were both axial prospective ECG-triggered. The vessel diameters and vessel attenuation values of totally 280 measurements from 140 coronary arteries were analyzed by two experienced radiologists. All data was analyzed by intraclass correlation test. Image quality graded by motion and stair step artifacts (grade 1, poor, to grade 4, excellent), accuracy of vessel inner and outer diameters were compared between the two CT units using the independent samples t-test and Mann-Whitney U test. The intraclass correlation coefficient (ICC) of measured vessel attenuation values in SDCT between the two radiologists was exceedingly good. The ICC was higher in HDCT. The radiation dose of HDCT was higher than that of SDCT. The mean tube current was 180 (mA) in HDCT and 147(mA) in SDCT with the same tube voltage (kVp). There was no significant difference between image quality. HDCT has a higher radiation dose but has much more atenuation and the spatial resolution which improve measurement accuracy for imaging coronary arteries.

Virtual reality hardware and graphic display options for brain-machine interfaces

PubMed Central

Marathe, Amar R.; Carey, Holle L.; Taylor, Dawn M.

2009-01-01

Virtual reality hardware and graphic displays are reviewed here as a development environment for brain-machine interfaces (BMIs). Two desktop stereoscopic monitors and one 2D monitor were compared in a visual depth discrimination task and in a 3D target-matching task where able-bodied individuals used actual hand movements to match a virtual hand to different target hands. Three graphic representations of the hand were compared: a plain sphere, a sphere attached to the fingertip of a realistic hand and arm, and a stylized pacman-like hand. Several subjects had great difficulty using either stereo monitor for depth perception when perspective size cues were removed. A mismatch in stereo and size cues generated inappropriate depth illusions. This phenomenon has implications for choosing target and virtual hand sizes in BMI experiments. Target matching accuracy was about as good with the 2D monitor as with either 3D monitor. However, users achieved this accuracy by exploring the boundaries of the hand in the target with carefully controlled movements. This method of determining relative depth may not be possible in BMI experiments if movement control is more limited. Intuitive depth cues, such as including a virtual arm, can significantly improve depth perception accuracy with or without stereo viewing. PMID:18006069

Application of time series discretization using evolutionary programming for classification of precancerous cervical lesions.

PubMed

Acosta-Mesa, Héctor-Gabriel; Rechy-Ramírez, Fernando; Mezura-Montes, Efrén; Cruz-Ramírez, Nicandro; Hernández Jiménez, Rodolfo

2014-06-01

In this work, we present a novel application of time series discretization using evolutionary programming for the classification of precancerous cervical lesions. The approach optimizes the number of intervals in which the length and amplitude of the time series should be compressed, preserving the important information for classification purposes. Using evolutionary programming, the search for a good discretization scheme is guided by a cost function which considers three criteria: the entropy regarding the classification, the complexity measured as the number of different strings needed to represent the complete data set, and the compression rate assessed as the length of the discrete representation. This discretization approach is evaluated using a time series data based on temporal patterns observed during a classical test used in cervical cancer detection; the classification accuracy reached by our method is compared with the well-known times series discretization algorithm SAX and the dimensionality reduction method PCA. Statistical analysis of the classification accuracy shows that the discrete representation is as efficient as the complete raw representation for the present application, reducing the dimensionality of the time series length by 97%. This representation is also very competitive in terms of classification accuracy when compared with similar approaches. Copyright © 2014 Elsevier Inc. All rights reserved.

Using Language Sample Analysis in Clinical Practice: Measures of Grammatical Accuracy for Identifying Language Impairment in Preschool and School-Aged Children.

PubMed

Eisenberg, Sarita; Guo, Ling-Yu

2016-05-01

This article reviews the existing literature on the diagnostic accuracy of two grammatical accuracy measures for differentiating children with and without language impairment (LI) at preschool and early school age based on language samples. The first measure, the finite verb morphology composite (FVMC), is a narrow grammatical measure that computes children's overall accuracy of four verb tense morphemes. The second measure, percent grammatical utterances (PGU), is a broader grammatical measure that computes children's accuracy in producing grammatical utterances. The extant studies show that FVMC demonstrates acceptable (i.e., 80 to 89% accurate) to good (i.e., 90% accurate or higher) diagnostic accuracy for children between 4;0 (years;months) and 6;11 in conversational or narrative samples. In contrast, PGU yields acceptable to good diagnostic accuracy for children between 3;0 and 8;11 regardless of sample types. Given the diagnostic accuracy shown in the literature, we suggest that FVMC and PGU can be used as one piece of evidence for identifying children with LI in assessment when appropriate. However, FVMC or PGU should not be used as therapy goals directly. Instead, when children are low in FVMC or PGU, we suggest that follow-up analyses should be conducted to determine the verb tense morphemes or grammatical structures that children have difficulty with. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Comparison of Trained Clinician Ratings with Expert Ratings of Aspiration on Videofluoroscopic Images from a Randomized Clinical Trial

PubMed Central

Hind, Jacqueline A.; Gensler, Gary; Brandt, Diane K.; Miller Gardner, Patricia J.; Blumenthal, Loreen; Gramigna, Gary D.; Kosek, Steven; Lundy, Donna; McGarvey-Toler, Susan; Rockafellow, Susan; Sullivan, Paula A.; Villa, Marybell; Gill, Gary D.; Lindblad, Anne S.; Logemann, Jeri A.; Robbins, JoAnne

2009-01-01

Accurate detection and classification of aspiration is a critical component of videofluoroscopic swallowing evaluation, the most commonly utilized instrumental method for dysphagia diagnosis and treatment. Currently published literature indicates that inter-judge reliability for the identification of aspiration ranges from poor to fairly good depending on the amount of training provided to clinicians. The majority of extant studies compared judgments among clinicians. No studies included judgments made during the use of a postural compensatory strategy. The purpose of this study was to examine the accuracy of judgments made by speech-language pathologists (SLPs) practicing in hospitals compared with unblinded expert judges when identifying aspiration and using the 8-point Penetration/Aspiration Scale. Clinicians received extensive training for the detection of aspiration and minimal training on use of the Penetration/Aspiration Scale. Videofluoroscopic data were collected from 669 patients as part of a large, randomized clinical trial and include judgments of 10,200 swallows made by 76 clinicians from 44 hospitals in 11 states. Judgments were made on swallows during use of dysphagia compensatory strategies: chin down posture with thin-liquids and thickened liquids (nectar-thick and honey-thick consistencies) in a head neutral posture. The subject population included patients with Parkinson’s disease and/or dementia. Kappa statistics indicate high accuracy for all interventions by SLPs for identification of aspiration (all К > .86) and variable accuracy (range 69%–76%) using the Penetration/Aspiration Scale when compared to expert judges. It is concluded that while the accuracy of identifying the presence of aspiration by SLPs is excellent, more extensive training and/or image enhancement is recommended for precise use of the Penetration/Aspiration Scale. PMID:18953607

SLOWLY REPEATED EVOKED PAIN (SREP) AS A MARKER OF CENTRAL SENSITIZATION IN FIBROMYALGIA: DIAGNOSTIC ACCURACY AND RELIABILITY IN COMPARISON WITH TEMPORAL SUMMATION OF PAIN.

PubMed

de la Coba, Pablo; Bruehl, Stephen; Gálvez-Sánchez, Carmen María; Reyes Del Paso, Gustavo A

2018-05-01

This study examined the diagnostic accuracy and test-retest reliability of a novel dynamic evoked pain protocol (slowly repeated evoked pain; SREP) compared to temporal summation of pain (TSP), a standard index of central sensitization. Thirty-five fibromyalgia (FM) and 30 rheumatoid arthritis (RA) patients completed, in pseudorandomized order, a standard mechanical TSP protocol (10 stimuli of 1s duration at the thenar eminence using a 300g monofilament with 1s interstimulus interval) and the SREP protocol (9 suprathreshold pressure stimuli of 5s duration applied to the fingernail with a 30s interstimulus interval). In order to evaluate reliability for both protocols, they were repeated in a second session 4-7 days later. Evidence for significant pain sensitization over trials (increasing pain intensity ratings) was observed for SREP in FM (p<.001) but not in RA (p=.35), whereas significant sensitization was observed in both diagnostic groups for the TSP protocol (p's<.008). Compared to TSP, SREP demonstrated higher overall diagnostic accuracy (87.7% vs. 64.6%), greater sensitivity (0.89 vs. 0.57), and greater specificity (0.87 vs. 0.73) in discriminating between FM and RA patients. Test-retest reliability of SREP sensitization was good in FM (ICCs: 0.80), and moderate in RA (ICC: 0.68). SREP seems to be a dynamic evoked pain index tapping into pain sensitization that allows for greater diagnostic accuracy in identifying FM patients compared to a standard TSP protocol. Further research is needed to study mechanisms underlying SREP and the potential utility of adding SREP to standard pain evaluation protocols.

Validation of deformable image registration algorithms on CT images of ex vivo porcine bladders with fiducial markers.

PubMed

Wognum, S; Heethuis, S E; Rosario, T; Hoogeman, M S; Bel, A

2014-07-01

The spatial accuracy of deformable image registration (DIR) is important in the implementation of image guided adaptive radiotherapy techniques for cancer in the pelvic region. Validation of algorithms is best performed on phantoms with fiducial markers undergoing controlled large deformations. Excised porcine bladders, exhibiting similar filling and voiding behavior as human bladders, provide such an environment. The aim of this study was to determine the spatial accuracy of different DIR algorithms on CT images of ex vivo porcine bladders with radiopaque fiducial markers applied to the outer surface, for a range of bladder volumes, using various accuracy metrics. Five excised porcine bladders with a grid of 30-40 radiopaque fiducial markers attached to the outer wall were suspended inside a water-filled phantom. The bladder was filled with a controlled amount of water with added contrast medium for a range of filling volumes (100-400 ml in steps of 50 ml) using a luer lock syringe, and CT scans were acquired at each filling volume. DIR was performed for each data set, with the 100 ml bladder as the reference image. Six intensity-based algorithms (optical flow or demons-based) implemented in theMATLAB platform DIRART, a b-spline algorithm implemented in the commercial software package VelocityAI, and a structure-based algorithm (Symmetric Thin Plate Spline Robust Point Matching) were validated, using adequate parameter settings according to values previously published. The resulting deformation vector field from each registration was applied to the contoured bladder structures and to the marker coordinates for spatial error calculation. The quality of the algorithms was assessed by comparing the different error metrics across the different algorithms, and by comparing the effect of deformation magnitude (bladder volume difference) per algorithm, using the Independent Samples Kruskal-Wallis test. The authors found good structure accuracy without dependency on bladder volume difference for all but one algorithm, and with the best result for the structure-based algorithm. Spatial accuracy as assessed from marker errors was disappointing for all algorithms, especially for large volume differences, implying that the deformations described by the registration did not represent anatomically correct deformations. The structure-based algorithm performed the best in terms of marker error for the large volume difference (100-400 ml). In general, for the small volume difference (100-150 ml) the algorithms performed relatively similarly. The structure-based algorithm exhibited the best balance in performance between small and large volume differences, and among the intensity-based algorithms, the algorithm implemented in VelocityAI exhibited the best balance. Validation of multiple DIR algorithms on a novel physiological bladder phantom revealed that the structure accuracy was good for most algorithms, but that the spatial accuracy as assessed from markers was low for all algorithms, especially for large deformations. Hence, many of the available algorithms exhibit sufficient accuracy for contour propagation purposes, but possibly not for accurate dose accumulation.

Systematic assessment of survey scan and MS2-based abundance strategies for label-free quantitative proteomics using high-resolution MS data.

PubMed

Tu, Chengjian; Li, Jun; Sheng, Quanhu; Zhang, Ming; Qu, Jun

2014-04-04

Survey-scan-based label-free method have shown no compelling benefit over fragment ion (MS2)-based approaches when low-resolution mass spectrometry (MS) was used, the growing prevalence of high-resolution analyzers may have changed the game. This necessitates an updated, comparative investigation of these approaches for data acquired by high-resolution MS. Here, we compared survey scan-based (ion current, IC) and MS2-based abundance features including spectral-count (SpC) and MS2 total-ion-current (MS2-TIC), for quantitative analysis using various high-resolution LC/MS data sets. Key discoveries include: (i) study with seven different biological data sets revealed only IC achieved high reproducibility for lower-abundance proteins; (ii) evaluation with 5-replicate analyses of a yeast sample showed IC provided much higher quantitative precision and lower missing data; (iii) IC, SpC, and MS2-TIC all showed good quantitative linearity (R(2) > 0.99) over a >1000-fold concentration range; (iv) both MS2-TIC and IC showed good linear response to various protein loading amounts but not SpC; (v) quantification using a well-characterized CPTAC data set showed that IC exhibited markedly higher quantitative accuracy, higher sensitivity, and lower false-positives/false-negatives than both SpC and MS2-TIC. Therefore, IC achieved an overall superior performance than the MS2-based strategies in terms of reproducibility, missing data, quantitative dynamic range, quantitative accuracy, and biomarker discovery.

Systematic Assessment of Survey Scan and MS2-Based Abundance Strategies for Label-Free Quantitative Proteomics Using High-Resolution MS Data

PubMed Central

2015-01-01

Survey-scan-based label-free method have shown no compelling benefit over fragment ion (MS2)-based approaches when low-resolution mass spectrometry (MS) was used, the growing prevalence of high-resolution analyzers may have changed the game. This necessitates an updated, comparative investigation of these approaches for data acquired by high-resolution MS. Here, we compared survey scan-based (ion current, IC) and MS2-based abundance features including spectral-count (SpC) and MS2 total-ion-current (MS2-TIC), for quantitative analysis using various high-resolution LC/MS data sets. Key discoveries include: (i) study with seven different biological data sets revealed only IC achieved high reproducibility for lower-abundance proteins; (ii) evaluation with 5-replicate analyses of a yeast sample showed IC provided much higher quantitative precision and lower missing data; (iii) IC, SpC, and MS2-TIC all showed good quantitative linearity (R2 > 0.99) over a >1000-fold concentration range; (iv) both MS2-TIC and IC showed good linear response to various protein loading amounts but not SpC; (v) quantification using a well-characterized CPTAC data set showed that IC exhibited markedly higher quantitative accuracy, higher sensitivity, and lower false-positives/false-negatives than both SpC and MS2-TIC. Therefore, IC achieved an overall superior performance than the MS2-based strategies in terms of reproducibility, missing data, quantitative dynamic range, quantitative accuracy, and biomarker discovery. PMID:24635752

Allergen-specific IgE measurement with the IMMULITE 2000 system: intermethod comparison of detection performance for allergen-specific IgE antibodies from Korean allergic patients.

PubMed

Lee, Yong Won; Sohn, Jung Ho; Lee, Jae-Hyun; Hong, Chein-Soo; Park, Jung-Won

2009-03-01

Intermethod comparison between IMMULITE 2000 chemiluminescent enzyme immunoassay (CLEIA) and the established CAP test for allergen-specific IgE (sIgE) has only been evaluated by a few studies. We performed such an interassay comparison using 283 Korean allergic patients with the following: asthma (18.4%), allergic rhinitis (18.4%), both asthma and allergic rhinitis (14.5%), atopic dermatitis (21.9%), and others (26.8%). We compared the sIgE detection performance of both systems for 10 major inhalant allergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae, Blattela germanica, cat dander, dog hair, alder, birch, oak, ragweed, and mugwort) and four food allergens (egg white, cow milk, peanut, and shrimp). After 645 paired comparison tests, close association and significant correlation were observed between the results of both assays for most of these allergens (r=0.525-0.979, p<0.05, respectively), except for shrimp. Intermethod agreement based on sIgE detection was fair to good (74.1-100%, kappa=0.514-1.000, p<0.05, respectively) for most allergens except for B. germanica, ragweed, and shrimp. Although both assays showed good accuracy in ROC curve analysis, some minor differences were noted. IMMULITE 2000 CLEIA for sIgE detection showed fair to good intermethod correlation, association, agreement, and accuracy in comparison to the established CAP assay among Korean allergic patients. However, we should take into account the intermethod differences between both assays for clinical applications.

Comparison of laser anemometer measurements and theory in an annular turbine cascade with experimental accuracy determined by parameter estimation

NASA Technical Reports Server (NTRS)

Goldman, L. J.; Seasholtz, R. G.

1982-01-01

Experimental measurements of the velocity components in the blade to blade (axial tangential) plane were obtained with an axial flow turbine stator passage and were compared with calculations from three turbomachinery computer programs. The theoretical results were calculated from a quasi three dimensional inviscid code, a three dimensional inviscid code, and a three dimensional viscous code. Parameter estimation techniques and a particle dynamics calculation were used to assess the accuracy of the laser measurements, which allow a rational basis for comparison of the experimenal and theoretical results. The general agreement of the experimental data with the results from the two inviscid computer codes indicates the usefulness of these calculation procedures for turbomachinery blading. The comparison with the viscous code, while generally reasonable, was not as good as for the inviscid codes.

An interval precise integration method for transient unbalance response analysis of rotor system with uncertainty

NASA Astrophysics Data System (ADS)

Fu, Chao; Ren, Xingmin; Yang, Yongfeng; Xia, Yebao; Deng, Wangqun

2018-07-01

A non-intrusive interval precise integration method (IPIM) is proposed in this paper to analyze the transient unbalance response of uncertain rotor systems. The transfer matrix method (TMM) is used to derive the deterministic equations of motion of a hollow-shaft overhung rotor. The uncertain transient dynamic problem is solved by combing the Chebyshev approximation theory with the modified precise integration method (PIM). Transient response bounds are calculated by interval arithmetic of the expansion coefficients. Theoretical error analysis of the proposed method is provided briefly, and its accuracy is further validated by comparing with the scanning method in simulations. Numerical results show that the IPIM can keep good accuracy in vibration prediction of the start-up transient process. Furthermore, the proposed method can also provide theoretical guidance to other transient dynamic mechanical systems with uncertainties.

Marine Targets Detection in Pol-SAR Data

NASA Astrophysics Data System (ADS)

Chen, Peng; Yang, Jingsong

2016-08-01

In this poster, we present a new method of marine target detection in Pol-SAR data. One band SAR image, like HH, VV or VH, can be used to find marine target using a Contant False Alarm Ratio (CFAR) algorithm. But some false detection may happen, as the sidelobe of antenna, Azimuth ambiguity, strong speckle noise and so on in the single band SAR image. Pol-SAR image can get more information of targets. After decomposition and false color composite, the sidelobe of antenna and Azimuth ambiguity could be deleted. So, the method presented include three steps, decomposion, false color composite and supervised classification. The result of Radarsat-2 SAR image test indicates a good accuracy. The detection results are compared with Automatic Indentify Sistem (AIS) data, the accuracy of right detection is above 95% and false detection ratio is below 5%.

Results of the first complete static calibration of the RSRA rotor-load-measurement system

NASA Technical Reports Server (NTRS)

Acree, C. W., Jr.

1984-01-01

The compound Rotor System Research Aircraft (RSRA) is designed to make high-accuracy, simultaneous measurements of all rotor forces and moments in flight. Physical calibration of the rotor force- and moment-measurement system when installed in the aircraft is required to account for known errors and to ensure that measurement-system accuracy is traceable to the National Bureau of Standards. The first static calibration and associated analysis have been completed with good results. Hysteresis was a potential cause of static calibration errors, but was found to be negligible in flight compared to full-scale loads, and analytical methods have been devised to eliminate hysteresis effects on calibration data. Flight tests confirmed that the calibrated rotor-load-measurement system performs as expected in flight and that it can dependably make direct measurements of fuselage vertical drag in hover.

Measuring large aspherics using a commercially available 3D-coordinate measuring machine

NASA Astrophysics Data System (ADS)

Otto, Wolfgang; Matthes, Axel; Schiehle, Heinz

2000-07-01

A CNC-controlled precision measuring machine is a very powerful tool in the optical shop not only to determine the surface figure, but also to qualify the radius of curvature and conic constant of aspherics. We used a commercially available 3D-coordinate measuring machine (CMM, ZEISS UPMC 850 CARAT S-ACC) to measure the shape of the GEMINI 1-m convex secondary mirrors at different lapping and polishing stages. To determine the measuring accuracy we compared the mechanical measurements with the results achieved by means of an interferometrical test setup. The data obtained in an early stage of polishing were evaluated in Zernike polynomials which show a very good agreement. The deviation concerning long wave rotational symmetrical errors was 20 nm rms, whereas the accuracy measuring of mid spatial frequency deviations was limited to about 100 nm rms.

Accuracy, calibration and clinical performance of the EuroSCORE: can we reduce the number of variables?

PubMed

Ranucci, Marco; Castelvecchio, Serenella; Menicanti, Lorenzo; Frigiola, Alessandro; Pelissero, Gabriele

2010-03-01

The European system for cardiac operative risk evaluation (EuroSCORE) is currently used in many institutions and is considered a reference tool in many countries. We hypothesised that too many variables were included in the EuroSCORE using limited patient series. We tested different models using a limited number of variables. A total of 11150 adult patients undergoing cardiac operations at our institution (2001-2007) were retrospectively analysed. The 17 risk factors composing the EuroSCORE were separately analysed and ranked for accuracy of prediction of hospital mortality. Seventeen models were created by progressively including one factor at a time. The models were compared for accuracy with a receiver operating characteristics (ROC) analysis and area under the curve (AUC) evaluation. Calibration was tested with Hosmer-Lemeshow statistics. Clinical performance was assessed by comparing the predicted with the observed mortality rates. The best accuracy (AUC 0.76) was obtained using a model including only age, left ventricular ejection fraction, serum creatinine, emergency operation and non-isolated coronary operation. The EuroSCORE AUC (0.75) was not significantly different. Calibration and clinical performance were better in the five-factor model than in the EuroSCORE. Only in high-risk patients were 12 factors needed to achieve a good performance. Including many factors in multivariable logistic models increases the risk for overfitting, multicollinearity and human error. A five-factor model offers the same level of accuracy but demonstrated better calibration and clinical performance. Models with a limited number of factors may work better than complex models when applied to a limited number of patients. Copyright (c) 2009 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

Can generic paediatric mortality scores calculated 4 hours after admission be used as inclusion criteria for clinical trials?

PubMed Central

Leteurtre, Stéphane; Leclerc, Francis; Wirth, Jessica; Noizet, Odile; Magnenant, Eric; Sadik, Ahmed; Fourier, Catherine; Cremer, Robin

2004-01-01

Introduction Two generic paediatric mortality scoring systems have been validated in the paediatric intensive care unit (PICU). Paediatric RISk of Mortality (PRISM) requires an observation period of 24 hours, and PRISM III measures severity at two time points (at 12 hours and 24 hours) after admission, which represents a limitation for clinical trials that require earlier inclusion. The Paediatric Index of Mortality (PIM) is calculated 1 hour after admission but does not take into account the stabilization period following admission. To avoid these limitations, we chose to conduct assessments 4 hours after PICU admission. The aim of the present study was to validate PRISM, PRISM III and PIM at the time points for which they were developed, and to compare their accuracy in predicting mortality at those times with their accuracy at 4 hours. Methods All children admitted from June 1998 to May 2000 in one tertiary PICU were prospectively included. Data were collected to generate scores and predictions using PRISM, PRISM III and PIM. Results There were 802 consecutive admissions with 80 deaths. For the time points for which the scores were developed, observed and predicted mortality rates were significantly different for the three scores (P < 0.01) whereas all exhibited good discrimination (area under the receiver operating characteristic curve ≥0.83). At 4 hours after admission only the PIM had good calibration (P = 0.44), but all three scores exhibited good discrimination (area under the receiver operating characteristic curve ≥0.82). Conclusions Among the three scores calculated at 4 hours after admission, all had good discriminatory capacity but only the PIM score was well calibrated. Further studies are required before the PIM score at 4 hours can be used as an inclusion criterion in clinical trials. PMID:15312217

Diagnostic accuracy of refractometry for assessing bovine colostrum quality: A systematic review and meta-analysis.

PubMed

Buczinski, S; Vandeweerd, J M

2016-09-01

Provision of good quality colostrum [i.e., immunoglobulin G (IgG) concentration ≥50g/L] is the first step toward ensuring proper passive transfer of immunity for young calves. Precise quantification of colostrum IgG levels cannot be easily performed on the farm. Assessment of the refractive index using a Brix scale with a refractometer has been described as being highly correlated with IgG concentration in colostrum. The aim of this study was to perform a systematic review of the diagnostic accuracy of Brix refractometry to diagnose good quality colostrum. From 101 references initially obtain ed, 11 were included in the systematic review meta-analysis representing 4,251 colostrum samples. The prevalence of good colostrum samples with IgG ≥50g/L varied from 67.3 to 92.3% (median 77.9%). Specific estimates of accuracy [sensitivity (Se) and specificity (Sp)] were obtained for different reported cut-points using a hierarchical summary receiver operating characteristic curve model. For the cut-point of 22% (n=8 studies), Se=80.2% (95% CI: 71.1-87.0%) and Sp=82.6% (71.4-90.0%). Decreasing the cut-point to 18% increased Se [96.1% (91.8-98.2%)] and decreased Sp [54.5% (26.9-79.6%)]. Modeling the effect of these Brix accuracy estimates using a stochastic simulation and Bayes theorem showed that a positive result with the 22% Brix cut-point can be used to diagnose good quality colostrum (posttest probability of a good colostrum: 94.3% (90.7-96.9%). The posttest probability of good colostrum with a Brix value <18% was only 22.7% (12.3-39.2%). Based on this study, the 2 cut-points could be alternatively used to select good quality colostrum (sample with Brix ≥22%) or to discard poor quality colostrum (sample with Brix <18%). When sample results are between these 2 values, colostrum supplementation should be considered. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Development of a modified independent parallel reactions kinetic model and comparison with the distributed activation energy model for the pyrolysis of a wide variety of biomass fuels.

PubMed

Sfakiotakis, Stelios; Vamvuka, Despina

2015-12-01

The pyrolysis of six waste biomass samples was studied and the fuels were kinetically evaluated. A modified independent parallel reactions scheme (IPR) and a distributed activation energy model (DAEM) were developed and their validity was assessed and compared by checking their accuracy of fitting the experimental results, as well as their prediction capability in different experimental conditions. The pyrolysis experiments were carried out in a thermogravimetric analyzer and a fitting procedure, based on least squares minimization, was performed simultaneously at different experimental conditions. A modification of the IPR model, considering dependence of the pre-exponential factor on heating rate, was proved to give better fit results for the same number of tuned kinetic parameters, comparing to the known IPR model and very good prediction results for stepwise experiments. Fit of calculated data to the experimental ones using the developed DAEM model was also proved to be very good. Copyright © 2015 Elsevier Ltd. All rights reserved.

Good Exemplars of Natural Scene Categories Elicit Clearer Patterns than Bad Exemplars but Not Greater BOLD Activity

PubMed Central

Torralbo, Ana; Walther, Dirk B.; Chai, Barry; Caddigan, Eamon; Fei-Fei, Li; Beck, Diane M.

2013-01-01

Within the range of images that we might categorize as a “beach”, for example, some will be more representative of that category than others. Here we first confirmed that humans could categorize “good” exemplars better than “bad” exemplars of six scene categories and then explored whether brain regions previously implicated in natural scene categorization showed a similar sensitivity to how well an image exemplifies a category. In a behavioral experiment participants were more accurate and faster at categorizing good than bad exemplars of natural scenes. In an fMRI experiment participants passively viewed blocks of good or bad exemplars from the same six categories. A multi-voxel pattern classifier trained to discriminate among category blocks showed higher decoding accuracy for good than bad exemplars in the PPA, RSC and V1. This difference in decoding accuracy cannot be explained by differences in overall BOLD signal, as average BOLD activity was either equivalent or higher for bad than good scenes in these areas. These results provide further evidence that V1, RSC and the PPA not only contain information relevant for natural scene categorization, but their activity patterns mirror the fundamentally graded nature of human categories. Analysis of the image statistics of our good and bad exemplars shows that variability in low-level features and image structure is higher among bad than good exemplars. A simulation of our neuroimaging experiment suggests that such a difference in variance could account for the observed differences in decoding accuracy. These results are consistent with both low-level models of scene categorization and models that build categories around a prototype. PMID:23555588

Capsule Endoscopy in the Assessment of Obscure Gastrointestinal Bleeding: An Evidence-Based Analysis

PubMed Central

2015-01-01

Background Obscure gastrointestinal bleeding (OGIB) is defined as persistent or recurrent bleeding associated with negative findings on upper and lower gastrointestinal (GI) endoscopic evaluations. The diagnosis and management of patients with OGIB is particularly challenging because of the length and complex loops of the small intestine. Capsule endoscopy (CE) is 1 diagnostic modality that is used to determine the etiology of bleeding. Objectives The objective of this analysis was to review the diagnostic accuracy, safety, and impact on health outcomes of CE in patients with OGIB in comparison with other diagnostic modalities. Data Sources A literature search was performed using Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid Embase, the Wiley Cochrane Library, and the Centre for Reviews and Dissemination database, for studies published between 2007 and 2013. Review Methods Data on diagnostic accuracy, safety, and impact on health outcomes were abstracted from included studies. Quality of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Results The search yielded 1,189 citations, and 24 studies were included. Eight studies reported diagnostic accuracy comparing CE with other diagnostic modalities. Capsule endoscopy has a higher sensitivity and lower specificity than magnetic resonance enteroclysis, computed tomography, and push enteroscopy. Capsule endoscopy has a good safety profile with few adverse events, although comparative safety data with other diagnostic modalities are limited. Capsule endoscopy is associated with no difference in patient health-related outcomes such as rebleeding or follow-up treatment compared with push enteroscopy, small-bowel follow-through, and angiography. Limitations There was significant heterogeneity in estimates of diagnostic accuracy, which prohibited a statistical summary of findings. The analysis was also limited by the fact that there is no established reference standard to which the diagnostic accuracy of CE can be compared. Conclusions There is very-low-quality evidence that CE has a higher sensitivity but a lower specificity than other diagnostic modalities. Capsule endoscopy has few adverse events, with capsule retention being the most serious complication. Capsule endoscopy is perceived by patients as less painful and less burdensome compared with other modalities. There is low-quality evidence that patients who undergo CE have similar rates of rebleeding, further therapeutic interventions, and hospitalization compared with other diagnostic modalities. PMID:26357529

Mean Expected Error in Prediction of Total Body Water: A True Accuracy Comparison between Bioimpedance Spectroscopy and Single Frequency Regression Equations

PubMed Central

Abtahi, Shirin; Abtahi, Farhad; Ellegård, Lars; Johannsson, Gudmundur; Bosaeus, Ingvar

2015-01-01

For several decades electrical bioimpedance (EBI) has been used to assess body fluid distribution and body composition. Despite the development of several different approaches for assessing total body water (TBW), it remains uncertain whether bioimpedance spectroscopic (BIS) approaches are more accurate than single frequency regression equations. The main objective of this study was to answer this question by calculating the expected accuracy of a single measurement for different EBI methods. The results of this study showed that all methods produced similarly high correlation and concordance coefficients, indicating good accuracy as a method. Even the limits of agreement produced from the Bland-Altman analysis indicated that the performance of single frequency, Sun's prediction equations, at population level was close to the performance of both BIS methods; however, when comparing the Mean Absolute Percentage Error value between the single frequency prediction equations and the BIS methods, a significant difference was obtained, indicating slightly better accuracy for the BIS methods. Despite the higher accuracy of BIS methods over 50 kHz prediction equations at both population and individual level, the magnitude of the improvement was small. Such slight improvement in accuracy of BIS methods is suggested insufficient to warrant their clinical use where the most accurate predictions of TBW are required, for example, when assessing over-fluidic status on dialysis. To reach expected errors below 4-5%, novel and individualized approaches must be developed to improve the accuracy of bioimpedance-based methods for the advent of innovative personalized health monitoring applications. PMID:26137489

Vocal Accuracy and Neural Plasticity Following Micromelody-Discrimination Training

PubMed Central

Zarate, Jean Mary; Delhommeau, Karine; Wood, Sean; Zatorre, Robert J.

2010-01-01

Background Recent behavioral studies report correlational evidence to suggest that non-musicians with good pitch discrimination sing more accurately than those with poorer auditory skills. However, other studies have reported a dissociation between perceptual and vocal production skills. In order to elucidate the relationship between auditory discrimination skills and vocal accuracy, we administered an auditory-discrimination training paradigm to a group of non-musicians to determine whether training-enhanced auditory discrimination would specifically result in improved vocal accuracy. Methodology/Principal Findings We utilized micromelodies (i.e., melodies with seven different interval scales, each smaller than a semitone) as the main stimuli for auditory discrimination training and testing, and we used single-note and melodic singing tasks to assess vocal accuracy in two groups of non-musicians (experimental and control). To determine if any training-induced improvements in vocal accuracy would be accompanied by related modulations in cortical activity during singing, the experimental group of non-musicians also performed the singing tasks while undergoing functional magnetic resonance imaging (fMRI). Following training, the experimental group exhibited significant enhancements in micromelody discrimination compared to controls. However, we did not observe a correlated improvement in vocal accuracy during single-note or melodic singing, nor did we detect any training-induced changes in activity within brain regions associated with singing. Conclusions/Significance Given the observations from our auditory training regimen, we therefore conclude that perceptual discrimination training alone is not sufficient to improve vocal accuracy in non-musicians, supporting the suggested dissociation between auditory perception and vocal production. PMID:20567521

Procedural Documentation and Accuracy Assessment of Bathymetric Maps and Area/Capacity Tables for Small Reservoirs

USGS Publications Warehouse

Wilson, Gary L.; Richards, Joseph M.

2006-01-01

Because of the increasing use and importance of lakes for water supply to communities, a repeatable and reliable procedure to determine lake bathymetry and capacity is needed. A method to determine the accuracy of the procedure will help ensure proper collection and use of the data and resulting products. It is important to clearly define the intended products and desired accuracy before conducting the bathymetric survey to ensure proper data collection. A survey-grade echo sounder and differential global positioning system receivers were used to collect water-depth and position data in December 2003 at Sugar Creek Lake near Moberly, Missouri. Data were collected along planned transects, with an additional set of quality-assurance data collected for use in accuracy computations. All collected data were imported into a geographic information system database. A bathymetric surface model, contour map, and area/capacity tables were created from the geographic information system database. An accuracy assessment was completed on the collected data, bathymetric surface model, area/capacity table, and contour map products. Using established vertical accuracy standards, the accuracy of the collected data, bathymetric surface model, and contour map product was 0.67 foot, 0.91 foot, and 1.51 feet at the 95 percent confidence level. By comparing results from different transect intervals with the quality-assurance transect data, it was determined that a transect interval of 1 percent of the longitudinal length of Sugar Creek Lake produced nearly as good results as 0.5 percent transect interval for the bathymetric surface model, area/capacity table, and contour map products.

Accuracy of pedicle screw insertion in the thoracic and lumbar spine: a comparative study between percutaneous screw insertion and conventional open technique.

PubMed

Ikeuchi, Hiroko; Ikuta, Ko

2016-09-01

In the last decade, posterior instrumented fusion using percutaneous pedicle screws (PPSs) had been growing in popularity, and its safety and good clinical results have been reported. However, there have been few previous reports of the accuracy of PPS placement compared with that of conventional open screw insertion in an institution. This study aimed to evaluate the accuracy of PPS placement compared with that of conventional open technique. One hundred patients were treated with posterior instrumented fusion of the thoracic and lumbar spine from April 2008 to July 2013. Four cases of revised instrumentation surgery were excluded. In this study, the pedicle screws inserted below Th7 were investigated, therefore, a total of 455 screws were enrolled. Two hundred and ninety-three pedicle screws were conventional open-inserted screws (O-group) and 162 screws were PPSs (P-group). We conducted a comparative study about the accuracy of placement between the two groups. Postoperative computed tomography scans were carried out to all patients, and the pedicle screw position was assessed according to a scoring system described by Zdichavsky et al. (Eur J Trauma 30:241-247, 2004; Eur J Trauma 30:234-240, 2004) and a classification described by Wiesner et al. (Spine 24:1599-1603, 1999). Based on Zdichavsky's scoring system, the number of grade Ia screws was 283 (96.6 %) in the O-group and 153 (94.4 %) in the P-group, whereas 5 screws (1.7 %) in the O-group and one screw (0.6 %) in the P-group were grade IIIa/IIIb. Meanwhile, the pedicle wall penetrations based on Wiesner classification were demonstrated in 20 screws (6.8 %) in the O-group, and 12 screws (7.4 %) in the P-group. No neurologic complications were observed and no screws had to be replaced in both groups. The PPSs could be ideally inserted without complications. There were no statistically significant differences about the accuracy between the conventional open insertion and PPS placement.

Protein levels of ADAM10, BACE1, and PSEN1 in platelets and leukocytes of Alzheimer's disease patients.

PubMed

Bram, Jessyka Maria de França; Talib, Leda Leme; Joaquim, Helena Passarelli Giroud; Sarno, Tamires Alves; Gattaz, Wagner Farid; Forlenza, Orestes Vicente

2018-05-29

The clinical diagnosis of Alzheimer's disease (AD) is a probabilistic formulation that may lack accuracy particularly at early stages of the dementing process. Abnormalities in amyloid-beta precursor protein (APP) metabolism and in the level of APP secretases have been demonstrated in platelets, and to a lesser extent in leukocytes, of AD patients, with conflicting results. The aim of the present study was to compare the protein level of the APP secretases A-disintegrin and metalloprotease 10 (ADAM10), Beta-site APP-cleaving enzyme 1 (BACE1), and presenilin-1 (PSEN1) in platelets and leukocytes from 20 non-medicated older adults with AD and 20 healthy elders, and to determine the potential use of these biomarkers to discriminate cases of AD from controls. The protein levels of all APP secretases were significantly higher in platelets compared to leukocytes. We found statistically a significant decrease in ADAM10 (52.5%, p < 0.0001) and PSEN1 (32%, p = 0.02) in platelets from AD patients compared to controls, but not in leukocytes. Combining all three secretases to generate receiver-operating characteristic (ROC) curves, we found a good discriminatory effect (AD vs. controls) when using platelets (the area under the curve-AUC-0.90, sensitivity 88.9%, specificity 66.7%, p = 0.003), but not in leukocytes (AUC 0.65, sensitivity 77.8%, specificity 50.0%, p = 0.2). Our findings indicate that platelets represent a better biological matrix than leukocytes to address the peripheral level of APP secretases. In addition, combining the protein level of ADAM10, BACE1, and PSEN1 in platelets, yielded a good accuracy to discriminate AD from controls.

Tabu search and binary particle swarm optimization for feature selection using microarray data.

PubMed

Chuang, Li-Yeh; Yang, Cheng-Huei; Yang, Cheng-Hong

2009-12-01

Gene expression profiles have great potential as a medical diagnosis tool because they represent the state of a cell at the molecular level. In the classification of cancer type research, available training datasets generally have a fairly small sample size compared to the number of genes involved. This fact poses an unprecedented challenge to some classification methodologies due to training data limitations. Therefore, a good selection method for genes relevant for sample classification is needed to improve the predictive accuracy, and to avoid incomprehensibility due to the large number of genes investigated. In this article, we propose to combine tabu search (TS) and binary particle swarm optimization (BPSO) for feature selection. BPSO acts as a local optimizer each time the TS has been run for a single generation. The K-nearest neighbor method with leave-one-out cross-validation and support vector machine with one-versus-rest serve as evaluators of the TS and BPSO. The proposed method is applied and compared to the 11 classification problems taken from the literature. Experimental results show that our method simplifies features effectively and either obtains higher classification accuracy or uses fewer features compared to other feature selection methods.

Assessment of an Euler-Interacting Boundary Layer Method Using High Reynolds Number Transonic Flight Data

NASA Technical Reports Server (NTRS)

Bonhaus, Daryl L.; Maddalon, Dal V.

1998-01-01

Flight-measured high Reynolds number turbulent-flow pressure distributions on a transport wing in transonic flow are compared to unstructured-grid calculations to assess the predictive ability of a three-dimensional Euler code (USM3D) coupled to an interacting boundary layer module. The two experimental pressure distributions selected for comparative analysis with the calculations are complex and turbulent but typical of an advanced technology laminar flow wing. An advancing front method (VGRID) was used to generate several tetrahedral grids for each test case. Initial calculations left considerable room for improvement in accuracy. Studies were then made of experimental errors, transition location, viscous effects, nacelle flow modeling, number and placement of spanwise boundary layer stations, and grid resolution. The most significant improvements in the accuracy of the calculations were gained by improvement of the nacelle flow model and by refinement of the computational grid. Final calculations yield results in close agreement with the experiment. Indications are that further grid refinement would produce additional improvement but would require more computer memory than is available. The appendix data compare the experimental attachment line location with calculations for different grid sizes. Good agreement is obtained between the experimental and calculated attachment line locations.

Bicuspid aortic valves: diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT.

PubMed

Murphy, David J; McEvoy, Sinead H; Iyengar, Sri; Feuchtner, Gudrun; Cury, Ricardo C; Roobottom, Carl; Baumueller, Stephan; Alkadhi, Hatem; Dodd, Jonathan D

2014-08-01

To assess the diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT for bicuspid aortic valves. The standard axial chest CT scans of 20 patients with known bicuspid aortic valves were blindly, randomly analyzed for (i) the appearance of the valve cusps, (ii) the largest aortic sinus area, (iii) the longest aortic cusp length, (iv) the thickest aortic valve cusp and (v) valve calcification. A second blinded reader independently analyzed the appearance of the valve cusps. Forty-two age- and sex-matched patients with known tricuspid aortic valves were used as controls. Retrospectively ECG-gated cardiac CT multiphase reconstructions of the aortic valve were used as the gold-standard. Fourteen (21%) scans were scored as unevaluable (7 bicuspid, 7 tricuspid). Of the remainder, there were 13 evaluable bicuspid valves, ten of which showed an aortic valve line sign, while the remaining three showed a normal Mercedes-Benz appearance owing to fused valve cusps. The 35 evaluable tricuspid aortic valves all showed a normal Mercedes-Benz appearance (P=0.001). Kappa analysis=0.62 indicating good interobserver agreement for the aortic valve cusp appearance. Aortic sinus areas, aortic cusp lengths and aortic cusp thicknesses of ≥ 3.8 cm(2), 3.2 cm and 1.6mm respectively on standard axial chest CT best distinguished bicuspid from tricuspid aortic valves (P<0.0001 for all). Of evaluable scans, the sensitivity, specificity, positive and negative predictive values of standard axial chest CT in diagnosing bicuspid aortic valves was 77% (CI 0.54-1.0), 100%, 100% and 70% respectively. The aortic valve is evaluable in approximately 80% of standard chest 64-slice CT scans. Bicuspid aortic valves may be diagnosed on evaluable scans with good diagnostic accuracy. An aortic valve line sign, enlarged aortic sinuses and elongated, thickened valve cusps are specific CT features. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Heart rate measurement based on face video sequence

NASA Astrophysics Data System (ADS)

Xu, Fang; Zhou, Qin-Wu; Wu, Peng; Chen, Xing; Yang, Xiaofeng; Yan, Hong-jian

2015-03-01

This paper proposes a new non-contact heart rate measurement method based on photoplethysmography (PPG) theory. With this method we can measure heart rate remotely with a camera and ambient light. We collected video sequences of subjects, and detected remote PPG signals through video sequences. Remote PPG signals were analyzed with two methods, Blind Source Separation Technology (BSST) and Cross Spectral Power Technology (CSPT). BSST is a commonly used method, and CSPT is used for the first time in the study of remote PPG signals in this paper. Both of the methods can acquire heart rate, but compared with BSST, CSPT has clearer physical meaning, and the computational complexity of CSPT is lower than that of BSST. Our work shows that heart rates detected by CSPT method have good consistency with the heart rates measured by a finger clip oximeter. With good accuracy and low computational complexity, the CSPT method has a good prospect for the application in the field of home medical devices and mobile health devices.

Turbo-SMT: Accelerating Coupled Sparse Matrix-Tensor Factorizations by 200×

PubMed Central

Papalexakis, Evangelos E.; Faloutsos, Christos; Mitchell, Tom M.; Talukdar, Partha Pratim; Sidiropoulos, Nicholas D.; Murphy, Brian

2015-01-01

How can we correlate the neural activity in the human brain as it responds to typed words, with properties of these terms (like ‘edible’, ‘fits in hand’)? In short, we want to find latent variables, that jointly explain both the brain activity, as well as the behavioral responses. This is one of many settings of the Coupled Matrix-Tensor Factorization (CMTF) problem. Can we accelerate any CMTF solver, so that it runs within a few minutes instead of tens of hours to a day, while maintaining good accuracy? We introduce TURBO-SMT, a meta-method capable of doing exactly that: it boosts the performance of any CMTF algorithm, by up to 200×, along with an up to 65 fold increase in sparsity, with comparable accuracy to the baseline. We apply TURBO-SMT to BRAINQ, a dataset consisting of a (nouns, brain voxels, human subjects) tensor and a (nouns, properties) matrix, with coupling along the nouns dimension. TURBO-SMT is able to find meaningful latent variables, as well as to predict brain activity with competitive accuracy. PMID:26473087

Prognostic scores in oesophageal or gastric variceal bleeding.

PubMed

Ohmann, C; Stöltzing, H; Wins, L; Busch, E; Thon, K

1990-05-01

Numerous scoring systems have been developed for the prediction of outcome of variceal bleeding; however, only a few have been evaluated adequately. The object of this study was to improve the classical Child-Pugh score (CPS) and to test other scores from the literature. Patients (n = 82) with endoscopically confirmed variceal bleeding and long-term sclerotherapy were included in the study. Linear logistic regression (LR) was applied to different sets of prognostic variables with regard to 30-day mortality. In addition, scores from the literature were evaluated on the data set. Performance was measured by the accuracy and receiver-operating characteristic curves. The application of LR to all five CPS variables (accuracy, 80%) was superior to the classical CPS (70%). LR with selection from the CPS variables or from other sets of variables resulted in no improvement. Compared with CPS only three scores from the literature, mainly based on subsets of the CPS variables, showed an improved accuracy. It is concluded that CPS is still a good scoring system; however, it can be improved by statistical analysis using the same variables.

[Comparative Study on Evaluating the Bladder Volume between BladderScan BVI9400 and Ultrasound System iU22].

PubMed

Luo, Huanli; Wang, Ying; Li, Fang; Ling, Yun; Yang, Dingyi; Jin, Fu

2015-07-01

To evaluate the accuracy of the latest BladderScan BVI9400 on measuring bladder volume. Two bladder phantoms were selected for investigating the accuracy of BVI9400. 341 patients with the iU22 ultrasound examinations were followed by BVI 9400. The difference and correlation between BVI9400 and iU22 were contrastively analyzed. The relative difference between results from BVI9400 and phantom volume was 2.5% and 1.36%. There was a strong correlation for patients between BVI9400 and iU22 (R = 0.96, P < 0.001). The relative difference between BVI9400 and iU22 decreased with the increasing of bladder volume and had no significant difference with patient's gender (P > 0.1). BladderScan BVI9400 had the ability of high accuracy and good stability of measured data. In view of quick and conveniences, BVI9400 could be as auxiliary equipment on pelvic tumor to evaluate whether the bladder volume during fractional radiotherapy was consistency with that during CT positioning.

Impact of time-resolved MRA on diagnostic accuracy in patients with symptomatic peripheral artery disease of the calf station.

PubMed

Hansmann, Jan; Michaely, Henrik J; Morelli, John N; Diehl, Steffen J; Meyer, Mathias; Schoenberg, Stefan O; Attenberger, Ulrike I

2013-12-01

The purpose of this article is to evaluate the added diagnostic accuracy of time-resolved MR angiography (MRA) of the calves compared with continuous-table-movement MRA in patients with symptomatic lower extremity peripheral artery disease (PAD) using digital subtraction angiography (DSA) correlation. Eighty-four consecutive patients with symptomatic PAD underwent a low-dose 3-T MRA protocol, consisting of continuous-table-movement MRA, acquired from the diaphragm to the calves, and an additional time-resolved MRA of the calves; 0.1 mmol/kg body weight (bw) of contrast material was used (0.07 mmol/kg bw for continuous-table-movement MRA and 0.03 mmol/kg bw for time-resolved MRA). Two radiologists rated image quality on a 4-point scale and stenosis degree on a 3-point scale. An additional assessment determined the degree of venous contamination and whether time-resolved MRA improved diagnostic confidence. The accuracy of stenosis gradation with continuous-table-movement and time-resolved MRA was compared with that of DSA as a correlation. Overall diagnostic accuracy was calculated for continuous-table-movement and time-resolved MRA. Median image quality was rated as good for 578 vessel segments with continuous-table-movement MRA and as excellent for 565 vessel segments with time-resolved MRA. Interreader agreement was excellent (κ = 0.80-0.84). Venous contamination interfered with diagnosis in more than 60% of continuous-table-movement MRA examinations. The degree of stenosis was assessed for 340 vessel segments. The diagnostic accuracies (continuous-table-movement MRA/time-resolved MRA) combined for the readers were obtained for the tibioperoneal trunk (84%/93%), anterior tibial (69%/87%), posterior tibial (85%/91%), and peroneal (67%/81%) arteries. The addition of time-resolved MRA improved diagnostic confidence in 69% of examinations. The addition of time-resolved MRA at the calf station improves diagnostic accuracy over continuous-table-movement MRA alone in symptomatic patients with PAD.

Accuracy of urinary human papillomavirus testing for presence of cervical HPV: systematic review and meta-analysis

PubMed Central

Pathak, Neha; Dodds, Julie; Khan, Khalid

2014-01-01

Objective To determine the accuracy of testing for human papillomavirus (HPV) DNA in urine in detecting cervical HPV in sexually active women. Design Systematic review and meta-analysis. Data sources Searches of electronic databases from inception until December 2013, checks of reference lists, manual searches of recent issues of relevant journals, and contact with experts. Eligibility criteria Test accuracy studies in sexually active women that compared detection of urine HPV DNA with detection of cervical HPV DNA. Data extraction and synthesis Data relating to patient characteristics, study context, risk of bias, and test accuracy. 2×2 tables were constructed and synthesised by bivariate mixed effects meta-analysis. Results 16 articles reporting on 14 studies (1443 women) were eligible for meta-analysis. Most used commercial polymerase chain reaction methods on first void urine samples. Urine detection of any HPV had a pooled sensitivity of 87% (95% confidence interval 78% to 92%) and specificity of 94% (95% confidence interval 82% to 98%). Urine detection of high risk HPV had a pooled sensitivity of 77% (68% to 84%) and specificity of 88% (58% to 97%). Urine detection of HPV 16 and 18 had a pooled sensitivity of 73% (56% to 86%) and specificity of 98% (91% to 100%). Metaregression revealed an increase in sensitivity when urine samples were collected as first void compared with random or midstream (P=0.004). Limitations The major limitations of this review are the lack of a strictly uniform method for the detection of HPV in urine and the variation in accuracy between individual studies. Conclusions Testing urine for HPV seems to have good accuracy for the detection of cervical HPV, and testing first void urine samples is more accurate than random or midstream sampling. When cervical HPV detection is considered difficult in particular subgroups, urine testing should be regarded as an acceptable alternative. PMID:25232064

Intercomparison of Laboratory Radiance Calibration Standards

NASA Technical Reports Server (NTRS)

Pavri, Betina; Chrien, Tom; Green, Robert; Williams, Orlesa

2000-01-01

Several standards for radiometric calibration were measured repeatedly with a spectroradiometer in order to understand how they compared in accuracy and stability. The tested radiance standards included a NIST 1000 W bulb and halon panel, two calibrated and stabilized integrating spheres, and a cavity blackbody. Results indicate good agreement between the blackbody and 1000 W bulb/spectralon panel, If these two radiance sources are assumed correct, then the integrating spheres did not conform. to their manufacturer-reported radiances in several regions of the spectrum. More detailed measurements am underway to investigate the discrepancy.

Comparison of Control Group Generating Methods.

PubMed

Szekér, Szabolcs; Fogarassy, György; Vathy-Fogarassy, Ágnes

2017-01-01

Retrospective studies suffer from drawbacks such as selection bias. As the selection of the control group has a significant impact on the evaluation of the results, it is very important to find the proper method to generate the most appropriate control group. In this paper we suggest two nearest neighbors based control group selection methods that aim to achieve good matching between the individuals of case and control groups. The effectiveness of the proposed methods is evaluated by runtime and accuracy tests and the results are compared to the classical stratified sampling method.

SonotaCo network and CAMS

NASA Astrophysics Data System (ADS)

Koseki, Masahiro

2017-04-01

You might think that the newly developed CAMS video system can get much more fine results than the system of SonotaCo network. There are small differences between them surely, but the comparison between the statistics of them reveals both data are comparable in accuracy. We find that the SonotaCo system cannot detect slow velocity meteors as good as CAMS but it is superior for faster meteors. There is a more important difference between them, that is, the definition of meteor showers and this is resulting in curious stream data.

Modeling of layered anisotropic composite material based on effective medium theory

NASA Astrophysics Data System (ADS)

Bao, Yang; Song, Jiming

2018-04-01

In this paper, we present an efficient method to simulate multilayered anisotropic composite material with effective medium theory. Effective permittivity, permeability and orientation angle for a layered anisotropic composite medium are extracted with this equivalent model. We also derive analytical expressions for effective parameters and orientation angle with low frequency (LF) limit, which will be shown in detail. Numerical results are shown in comparing extracted effective parameters and orientation angle with analytical results from low frequency limit. Good agreements are achieved to demonstrate the accuracy of our efficient model.

The roles of family history of dyslexia, language, speech production and phonological processing in predicting literacy progress.

PubMed

Carroll, Julia M; Mundy, Ian R; Cunningham, Anna J

2014-09-01

It is well established that speech, language and phonological skills are closely associated with literacy, and that children with a family risk of dyslexia (FRD) tend to show deficits in each of these areas in the preschool years. This paper examines what the relationships are between FRD and these skills, and whether deficits in speech, language and phonological processing fully account for the increased risk of dyslexia in children with FRD. One hundred and fifty-three 4-6-year-old children, 44 of whom had FRD, completed a battery of speech, language, phonology and literacy tasks. Word reading and spelling were retested 6 months later, and text reading accuracy and reading comprehension were tested 3 years later. The children with FRD were at increased risk of developing difficulties in reading accuracy, but not reading comprehension. Four groups were compared: good and poor readers with and without FRD. In most cases good readers outperformed poor readers regardless of family history, but there was an effect of family history on naming and nonword repetition regardless of literacy outcome, suggesting a role for speech production skills as an endophenotype of dyslexia. Phonological processing predicted spelling, while language predicted text reading accuracy and comprehension. FRD was a significant additional predictor of reading and spelling after controlling for speech production, language and phonological processing, suggesting that children with FRD show additional difficulties in literacy that cannot be fully explained in terms of their language and phonological skills. © 2014 John Wiley & Sons Ltd.

The relationship between transorbital ultrasound measurement of the optic nerve sheath diameter (ONSD) and invasively measured ICP in children : Part I: repeatability, observer variability and general analysis.

PubMed

Padayachy, Llewellyn C; Padayachy, Vaishali; Galal, Ushma; Gray, Rebecca; Fieggen, A Graham

2016-10-01

The aim of this study was to investigate the relationship between optic nerve sheath diameter (ONSD) measurement and invasively measured intracranial pressure (ICP) in children. ONSD measurement was performed prior to invasive measurement of ICP. The mean binocular ONSD measurement was compared to the ICP reading. Physiological variables including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse rate, temperature, respiratory rate and end tidal carbon dioxide (ETCO2) level were recorded at the time of ONSD measurement. Diagnostic accuracy analysis was performed at various ICP thresholds and  repeatability, intra- and inter-observer variability, correlation between measurements in different imaging planes as well the relationship over the entire patient cohort were examined in part I of this study. Data from 174 patients were analysed. Repeatability and intra-observer variability were excellent (α = 0.97-0.99). Testing for inter-observer variability revealed good correlation (r = 0.89, p < 0.001). Imaging in the sagittal plane demonstrated a slightly better correlation with ICP (r = 0.66, p < 0.001). The ONSD measurement with the best diagnostic accuracy for detecting an ICP ≥ 20 mmHg over the entire patient cohort was 5.5 mm, sensitivity 93.2 %, specificity 74 % and odds ratio (OR) of 39.3. Transorbital ultrasound measurement of the OSND is a reliable and reproducible technique, demonstrating a good relationship with ICP and high diagnostic accuracy for detecting raised ICP.

Prospective Evaluation of Noninvasive HeadSense Intracranial Pressure Monitor in Traumatic Brain Injury Patients Undergoing Invasive Intracranial Pressure Monitoring.

PubMed

Herklots, Martin W; Moudrous, Walid; Oldenbeuving, Annemarie; Roks, Gerwin; Mourtzoukos, Stylianos; Schoonman, Guus G; Ganslandt, Oliver

2017-10-01

Currently, intracranial pressure (ICP) is measured by invasive methods with a significant risk of infectious and hemorrhagic complications. Because of these high risks, there is a need for a noninvasive ICP (nICP) monitor with an accuracy similar to that of an invasive ICP (iICP) monitor. We sought to assess prospectively the accuracy and precision of an nICP monitor compared with iICP measurement in severe traumatic brain injury (TBI) patients. Participants were ICP-monitored patients who had sustained TBI. In parallel with the standard invasive ICP measurements, nICP was measured by the HeadSense HS-1000, which is based on sound propagation. The device generated an acoustic signal using a small transmitter, placed in the patient's ear, and picked up by an acoustic sensor placed in the other ear. The signal is then analyzed using proprietary algorithms, and the ICP value is calculated in millimeter of mercury (mm Hg). Analysis of 2911 paired iICP and nICP measurements from 14 severe TBI patients showed a good accuracy of the nICP monitor indicated by a mean difference of 0.5 mm Hg. The precision was also good with a standard deviation of 3.9 mm Hg. The Pearson r correlation was 0.604 (P < 0.001). The HeadSense HS-1000 nICP monitor seems sufficiently accurate to measure the ICP in severe TBI patients, is patient friendly, and has minimal risk of complications. Copyright © 2017 Elsevier Inc. All rights reserved.

A Novel Methodology to Validate the Accuracy of Extraoral Dental Scanners and Digital Articulation Systems.

PubMed

Ellakwa, A; Elnajar, S; Littlefair, D; Sara, G

2018-05-03

The aim of the current study is to develop a novel method to investigate the accuracy of 3D scanners and digital articulation systems. An upper and a lower poured stone model were created by taking impression of fully dentate male (fifty years old) participant. Titanium spheres were added to the models to allow for an easily recognisable geometric shape for measurement after scanning and digital articulation. Measurements were obtained using a Coordinate Measuring Machine to record volumetric error, articulation error and clinical effect error. Three scanners were compared, including the Imetric 3D iScan d104i, Shining 3D AutoScan-DS100 and 3Shape D800, as well as their respective digital articulation software packages. Stoneglass Industries PDC digital articulation system was also applied to the Imetric scans for comparison with the CMM measurements. All the scans displayed low volumetric error (p⟩0.05), indicating that the scanners themselves had a minor contribution to the articulation and clinical effect errors. The PDC digital articulation system was found to deliver the lowest average errors, with good repeatability of results. The new measuring technique in the current study was able to assess the scanning and articulation accuracy of the four systems investigated. The PDC digital articulation system using Imetric scans was recommended as it displayed the lowest articulation error and clinical effect error with good repeatability. The low errors from the PDC system may have been due to its use of a 3D axis for alignment rather than the use of a best fit. Copyright© 2018 Dennis Barber Ltd.

Comparing writing style feature-based classification methods for estimating user reputations in social media.

PubMed

Suh, Jong Hwan

2016-01-01

In recent years, the anonymous nature of the Internet has made it difficult to detect manipulated user reputations in social media, as well as to ensure the qualities of users and their posts. To deal with this, this study designs and examines an automatic approach that adopts writing style features to estimate user reputations in social media. Under varying ways of defining Good and Bad classes of user reputations based on the collected data, it evaluates the classification performance of the state-of-art methods: four writing style features, i.e. lexical, syntactic, structural, and content-specific, and eight classification techniques, i.e. four base learners-C4.5, Neural Network (NN), Support Vector Machine (SVM), and Naïve Bayes (NB)-and four Random Subspace (RS) ensemble methods based on the four base learners. When South Korea's Web forum, Daum Agora, was selected as a test bed, the experimental results show that the configuration of the full feature set containing content-specific features and RS-SVM combining RS and SVM gives the best accuracy for classification if the test bed poster reputations are segmented strictly into Good and Bad classes by portfolio approach. Pairwise t tests on accuracy confirm two expectations coming from the literature reviews: first, the feature set adding content-specific features outperform the others; second, ensemble learning methods are more viable than base learners. Moreover, among the four ways on defining the classes of user reputations, i.e. like, dislike, sum, and portfolio, the results show that the portfolio approach gives the highest accuracy.

Ex vivo characterization of normal and adenocarcinoma colon samples by Mueller matrix polarimetry.

PubMed

Ahmad, Iftikhar; Ahmad, Manzoor; Khan, Karim; Ashraf, Sumara; Ahmad, Shakil; Ikram, Masroor

2015-05-01

Mueller matrix polarimetry along with polar decomposition algorithm was employed for the characterization of ex vivo normal and adenocarcinoma human colon tissues by polarized light in the visible spectral range (425-725 nm). Six derived polarization metrics [total diattenuation (DT ), retardance (RT ), depolarization(ΔT ), linear diattenuation (DL), retardance (δ), and depolarization (ΔL)] were compared for normal and adenocarcinoma colon tissue samples. The results show that all six polarimetric properties for adenocarcinoma samples were significantly higher as compared to the normal samples for all wavelengths. The Wilcoxon rank sum test illustrated that total retardance is a good candidate for the discrimination of normal and adenocarcinoma colon samples. Support vector machine classification for normal and adenocarcinoma based on the four polarization properties spectra (ΔT , ΔL, RT ,and δ) yielded 100% accuracy, sensitivity, and specificity, while both DTa nd DL showed 66.6%, 33.3%, and 83.3% accuracy, sensitivity, and specificity, respectively. The combination of polarization analysis and given classification methods provides a framework to distinguish the normal and cancerous tissues.

High variation subarctic topsoil pollutant concentration prediction using neural network residual kriging

NASA Astrophysics Data System (ADS)

Sergeev, A. P.; Tarasov, D. A.; Buevich, A. G.; Subbotina, I. E.; Shichkin, A. V.; Sergeeva, M. V.; Lvova, O. A.

2017-06-01

The work deals with the application of neural networks residual kriging (NNRK) to the spatial prediction of the abnormally distributed soil pollutant (Cr). It is known that combination of geostatistical interpolation approaches (kriging) and neural networks leads to significantly better prediction accuracy and productivity. Generalized regression neural networks and multilayer perceptrons are classes of neural networks widely used for the continuous function mapping. Each network has its own pros and cons; however both demonstrated fast training and good mapping possibilities. In the work, we examined and compared two combined techniques: generalized regression neural network residual kriging (GRNNRK) and multilayer perceptron residual kriging (MLPRK). The case study is based on the real data sets on surface contamination by chromium at a particular location of the subarctic Novy Urengoy, Russia, obtained during the previously conducted screening. The proposed models have been built, implemented and validated using ArcGIS and MATLAB environments. The networks structures have been chosen during a computer simulation based on the minimization of the RMSE. MLRPK showed the best predictive accuracy comparing to the geostatistical approach (kriging) and even to GRNNRK.

Development of a Cost-Effective Modular Pixelated NaI(Tl) Detector for Clinical SPECT Applications

PubMed Central

Rozler, Mike; Liang, Haoning; Chang, Wei

2013-01-01

A new pixelated detector for high-resolution clinical SPECT applications was designed and tested. The modular detector is based on a scintillator block comprised of 2.75×2.75×10 mm3 NaI(Tl) pixels and decoded by an array of 51 mm diameter single-anode PMTs. Several configurations, utilizing two types of PMTs, were evaluated using a collimated beam source to measure positioning accuracy directly. Good pixel separation was observed, with correct pixel identification ranging from 60 to 72% averaged over the entire area of the modules, depending on the PMT type and configuration. This translates to a significant improvement in positioning accuracy compared to continuous slab detectors of the same thickness, along with effective reduction of “dead” space at the edges. The observed 10% average energy resolution compares well to continuous slab detectors. The combined performance demonstrates the suitability of pixelated detectors decoded with a relatively small number of medium-sized PMTs as a cost-effective approach for high resolution clinical SPECT applications, in particular those involving curved detector geometries. PMID:24146436

Experimental Validation of Various Temperature Modells for Semi-Physical Tyre Model Approaches

NASA Astrophysics Data System (ADS)

Hackl, Andreas; Scherndl, Christoph; Hirschberg, Wolfgang; Lex, Cornelia

2017-10-01

With increasing level of complexity and automation in the area of automotive engineering, the simulation of safety relevant Advanced Driver Assistance Systems (ADAS) leads to increasing accuracy demands in the description of tyre contact forces. In recent years, with improvement in tyre simulation, the needs for coping with tyre temperatures and the resulting changes in tyre characteristics are rising significantly. Therefore, experimental validation of three different temperature model approaches is carried out, discussed and compared in the scope of this article. To investigate or rather evaluate the range of application of the presented approaches in combination with respect of further implementation in semi-physical tyre models, the main focus lies on the a physical parameterisation. Aside from good modelling accuracy, focus is held on computational time and complexity of the parameterisation process. To evaluate this process and discuss the results, measurements from a Hoosier racing tyre 6.0 / 18.0 10 LCO C2000 from an industrial flat test bench are used. Finally the simulation results are compared with the measurement data.

Methodological quality of diagnostic accuracy studies on non-invasive coronary CT angiography: influence of QUADAS (Quality Assessment of Diagnostic Accuracy Studies included in systematic reviews) items on sensitivity and specificity.

PubMed

Schueler, Sabine; Walther, Stefan; Schuetz, Georg M; Schlattmann, Peter; Dewey, Marc

2013-06-01

To evaluate the methodological quality of diagnostic accuracy studies on coronary computed tomography (CT) angiography using the QUADAS (Quality Assessment of Diagnostic Accuracy Studies included in systematic reviews) tool. Each QUADAS item was individually defined to adapt it to the special requirements of studies on coronary CT angiography. Two independent investigators analysed 118 studies using 12 QUADAS items. Meta-regression and pooled analyses were performed to identify possible effects of methodological quality items on estimates of diagnostic accuracy. The overall methodological quality of coronary CT studies was merely moderate. They fulfilled a median of 7.5 out of 12 items. Only 9 of the 118 studies fulfilled more than 75 % of possible QUADAS items. One QUADAS item ("Uninterpretable Results") showed a significant influence (P = 0.02) on estimates of diagnostic accuracy with "no fulfilment" increasing specificity from 86 to 90 %. Furthermore, pooled analysis revealed that each QUADAS item that is not fulfilled has the potential to change estimates of diagnostic accuracy. The methodological quality of studies investigating the diagnostic accuracy of non-invasive coronary CT is only moderate and was found to affect the sensitivity and specificity. An improvement is highly desirable because good methodology is crucial for adequately assessing imaging technologies. • Good methodological quality is a basic requirement in diagnostic accuracy studies. • Most coronary CT angiography studies have only been of moderate design quality. • Weak methodological quality will affect the sensitivity and specificity. • No improvement in methodological quality was observed over time. • Authors should consider the QUADAS checklist when undertaking accuracy studies.

Applications and accuracy of the parallel diagonal dominant algorithm

NASA Technical Reports Server (NTRS)

Sun, Xian-He

1993-01-01

The Parallel Diagonal Dominant (PDD) algorithm is a highly efficient, ideally scalable tridiagonal solver. In this paper, a detailed study of the PDD algorithm is given. First the PDD algorithm is introduced. Then the algorithm is extended to solve periodic tridiagonal systems. A variant, the reduced PDD algorithm, is also proposed. Accuracy analysis is provided for a class of tridiagonal systems, the symmetric, and anti-symmetric Toeplitz tridiagonal systems. Implementation results show that the analysis gives a good bound on the relative error, and the algorithm is a good candidate for the emerging massively parallel machines.

A Dynamic Precision Evaluation Method for the Star Sensor in the Stellar-Inertial Navigation System.

PubMed

Lu, Jiazhen; Lei, Chaohua; Yang, Yanqiang

2017-06-28

Integrating the advantages of INS (inertial navigation system) and the star sensor, the stellar-inertial navigation system has been used for a wide variety of applications. The star sensor is a high-precision attitude measurement instrument; therefore, determining how to validate its accuracy is critical in guaranteeing its practical precision. The dynamic precision evaluation of the star sensor is more difficult than a static precision evaluation because of dynamic reference values and other impacts. This paper proposes a dynamic precision verification method of star sensor with the aid of inertial navigation device to realize real-time attitude accuracy measurement. Based on the gold-standard reference generated by the star simulator, the altitude and azimuth angle errors of the star sensor are calculated for evaluation criteria. With the goal of diminishing the impacts of factors such as the sensors' drift and devices, the innovative aspect of this method is to employ static accuracy for comparison. If the dynamic results are as good as the static results, which have accuracy comparable to the single star sensor's precision, the practical precision of the star sensor is sufficiently high to meet the requirements of the system specification. The experiments demonstrate the feasibility and effectiveness of the proposed method.

A method for approximating acoustic-field-amplitude uncertainty caused by environmental uncertainties.

PubMed

James, Kevin R; Dowling, David R

2008-09-01

In underwater acoustics, the accuracy of computational field predictions is commonly limited by uncertainty in environmental parameters. An approximate technique for determining the probability density function (PDF) of computed field amplitude, A, from known environmental uncertainties is presented here. The technique can be applied to several, N, uncertain parameters simultaneously, requires N+1 field calculations, and can be used with any acoustic field model. The technique implicitly assumes independent input parameters and is based on finding the optimum spatial shift between field calculations completed at two different values of each uncertain parameter. This shift information is used to convert uncertain-environmental-parameter distributions into PDF(A). The technique's accuracy is good when the shifted fields match well. Its accuracy is evaluated in range-independent underwater sound channels via an L(1) error-norm defined between approximate and numerically converged results for PDF(A). In 50-m- and 100-m-deep sound channels with 0.5% uncertainty in depth (N=1) at frequencies between 100 and 800 Hz, and for ranges from 1 to 8 km, 95% of the approximate field-amplitude distributions generated L(1) values less than 0.52 using only two field calculations. Obtaining comparable accuracy from traditional methods requires of order 10 field calculations and up to 10(N) when N>1.

Impact of orthographic transparency on typical and atypical reading development: evidence in French-Spanish bilingual children.

PubMed

Lallier, Marie; Valdois, Sylviane; Lassus-Sangosse, Delphine; Prado, Chloé; Kandel, Sonia

2014-05-01

The present study aimed to quantify cross-linguistic modulations of the contribution of phonemic awareness skills and visual attention span (VA Span) skills (number of visual elements that can be processed simultaneously) to reading speed and accuracy in 18 Spanish-French balanced bilingual children with and without developmental dyslexia. The children were administered two similar reading batteries in French and Spanish. The deficits of the dyslexic children in reading accuracy were mainly visible in their opaque orthography (French) whereas difficulties indexed by reading speed were observed in both their opaque and transparent orthographies. Dyslexic children did not exhibit any phonemic awareness problems in French or in Spanish, but showed poor VA Span skills compared to their control peers. VA span skills correlated with reading accuracy and speed measures in both Spanish and French, whereas phonemic awareness correlated with reading accuracy only. Overall, the present results show that the VA Span is tightly related to reading speed regardless of orthographic transparency, and that it accounts for differences in reading performance between good and poor readers across languages. The present findings further suggest that VA Span skills may play a particularly important role in building-up specific word knowledge which is critical for lexical reading strategies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Inclusion of Population-specific Reference Panel from India to the 1000 Genomes Phase 3 Panel Improves Imputation Accuracy.

PubMed

Ahmad, Meraj; Sinha, Anubhav; Ghosh, Sreya; Kumar, Vikrant; Davila, Sonia; Yajnik, Chittaranjan S; Chandak, Giriraj R

2017-07-27

Imputation is a computational method based on the principle of haplotype sharing allowing enrichment of genome-wide association study datasets. It depends on the haplotype structure of the population and density of the genotype data. The 1000 Genomes Project led to the generation of imputation reference panels which have been used globally. However, recent studies have shown that population-specific panels provide better enrichment of genome-wide variants. We compared the imputation accuracy using 1000 Genomes phase 3 reference panel and a panel generated from genome-wide data on 407 individuals from Western India (WIP). The concordance of imputed variants was cross-checked with next-generation re-sequencing data on a subset of genomic regions. Further, using the genome-wide data from 1880 individuals, we demonstrate that WIP works better than the 1000 Genomes phase 3 panel and when merged with it, significantly improves the imputation accuracy throughout the minor allele frequency range. We also show that imputation using only South Asian component of the 1000 Genomes phase 3 panel works as good as the merged panel, making it computationally less intensive job. Thus, our study stresses that imputation accuracy using 1000 Genomes phase 3 panel can be further improved by including population-specific reference panels from South Asia.

Application of GA-SVM method with parameter optimization for landslide development prediction

NASA Astrophysics Data System (ADS)

Li, X. Z.; Kong, J. M.

2013-10-01

Prediction of landslide development process is always a hot issue in landslide research. So far, many methods for landslide displacement series prediction have been proposed. Support vector machine (SVM) has been proved to be a novel algorithm with good performance. However, the performance strongly depends on the right selection of the parameters (C and γ) of SVM model. In this study, we presented an application of GA-SVM method with parameter optimization in landslide displacement rate prediction. We selected a typical large-scale landslide in some hydro - electrical engineering area of Southwest China as a case. On the basis of analyzing the basic characteristics and monitoring data of the landslide, a single-factor GA-SVM model and a multi-factor GA-SVM model of the landslide were built. Moreover, the models were compared with single-factor and multi-factor SVM models of the landslide. The results show that, the four models have high prediction accuracies, but the accuracies of GA-SVM models are slightly higher than those of SVM models and the accuracies of multi-factor models are slightly higher than those of single-factor models for the landslide prediction. The accuracy of the multi-factor GA-SVM models is the highest, with the smallest RSME of 0.0009 and the biggest RI of 0.9992.

Measuring Blood Glucose Concentrations in Photometric Glucometers Requiring Very Small Sample Volumes.

PubMed

Demitri, Nevine; Zoubir, Abdelhak M

2017-01-01

Glucometers present an important self-monitoring tool for diabetes patients and, therefore, must exhibit high accuracy as well as good usability features. Based on an invasive photometric measurement principle that drastically reduces the volume of the blood sample needed from the patient, we present a framework that is capable of dealing with small blood samples, while maintaining the required accuracy. The framework consists of two major parts: 1) image segmentation; and 2) convergence detection. Step 1 is based on iterative mode-seeking methods to estimate the intensity value of the region of interest. We present several variations of these methods and give theoretical proofs of their convergence. Our approach is able to deal with changes in the number and position of clusters without any prior knowledge. Furthermore, we propose a method based on sparse approximation to decrease the computational load, while maintaining accuracy. Step 2 is achieved by employing temporal tracking and prediction, herewith decreasing the measurement time, and, thus, improving usability. Our framework is tested on several real datasets with different characteristics. We show that we are able to estimate the underlying glucose concentration from much smaller blood samples than is currently state of the art with sufficient accuracy according to the most recent ISO standards and reduce measurement time significantly compared to state-of-the-art methods.

Weight Multispectral Reconstruction Strategy for Enhanced Reconstruction Accuracy and Stability With Cerenkov Luminescence Tomography.

PubMed

Hongbo Guo; Xiaowei He; Muhan Liu; Zeyu Zhang; Zhenhua Hu; Jie Tian

2017-06-01

Cerenkov luminescence tomography (CLT) provides a novel technique for 3-D noninvasive detection of radiopharmaceuticals in living subjects. However, because of the severe scattering of Cerenkov light, the reconstruction accuracy and stability of CLT is still unsatisfied. In this paper, a modified weight multispectral CLT (wmCLT) reconstruction strategy was developed which split the Cerenkov radiation spectrum into several sub-spectral bands and weighted the sub-spectral results to obtain the final result. To better evaluate the property of the wmCLT reconstruction strategy in terms of accuracy, stability and practicability, several numerical simulation experiments and in vivo experiments were conducted and the results obtained were compared with the traditional multispectral CLT (mCLT) and hybrid-spectral CLT (hCLT) reconstruction strategies. The numerical simulation results indicated that wmCLT strategy significantly improved the accuracy of Cerenkov source localization and intensity quantitation and exhibited good stability in suppressing noise in numerical simulation experiments. And the comparison of the results achieved from different in vivo experiments further indicated significant improvement of the wmCLT strategy in terms of the shape recovery of the bladder and the spatial resolution of imaging xenograft tumors. Overall the strategy reported here will facilitate the development of nuclear and optical molecular tomography in theoretical study.

Investigation of a Coupled Arrhenius-Type/Rossard Equation of AH36 Material.

PubMed

Qin, Qin; Tian, Ming-Liang; Zhang, Peng

2017-04-13

High-temperature tensile testing of AH36 material in a wide range of temperatures (1173-1573 K) and strain rates (10 -4 -10 -2 s -1 ) has been obtained by using a Gleeble system. These experimental stress-strain data have been adopted to develop the constitutive equation. The constitutive equation of AH36 material was suggested based on the modified Arrhenius-type equation and the modified Rossard equation respectively. The results indicate that the constitutive equation is strongly influenced by temperature and strain, especially strain. Moreover, there is a good agreement between the predicted data of the modified Arrhenius-type equation and the experimental results when the strain is greater than 0.02. There is also good agreement between the predicted data of the Rossard equation and the experimental results when the strain is less than 0.02. Therefore, a coupled equation where the modified Arrhenius-type equation and Rossard equation are combined has been proposed to describe the constitutive equation of AH36 material according to the different strain values in order to improve the accuracy. The correlation coefficient between the computed and experimental flow stress data was 0.998. The minimum value of the average absolute relative error shows the high accuracy of the coupled equation compared with the two modified equations.

Development of a Smartphone-based reading system for lateral flow immunoassay.

PubMed

Lee, Sangdae; Kim, Giyoung; Moon, Jihea

2014-11-01

This study was conducted to develop and evaluate the performance of the Smartphone-based reading system for the lateral flow immunoassay (LFIA). Smartphone-based reading system consists of a Samsung Galaxy S2 Smartphone, Smartphone application, and a LFIA reader. LFIA reader is composed of the close-up lens with a focal length up to 30 mm, white LED light, lithium polymer battery, and main body. The Smartphone application for image acquisition and data analysis was developed on the Android platform. The standard curve was obtained by plotting the measured P(T)/P(c) or A(T)/A(c) ratio versus Salmonella standard concentration. The mean, standard deviation (SD), recovery, and relative standard deviation (RSD) were also calculated using additional experimental results. These data were compared with that obtained from the benchtop LFIA reader. The LOD in both systems was observed with 10(6) CFU/mL. The results show high accuracy and good reproducibility with a RSD less than 10% in the range of 10(6) to 10(9) CFU/mL. Due to the simple structure, good sensitivity, and high accuracy of the Smartphone-based reading system, this system can be substituted for the benchtop LFIA reader for point-of-care medical diagnostics.

A parametric finite element method for solid-state dewetting problems with anisotropic surface energies

NASA Astrophysics Data System (ADS)

Bao, Weizhu; Jiang, Wei; Wang, Yan; Zhao, Quan

2017-02-01

We propose an efficient and accurate parametric finite element method (PFEM) for solving sharp-interface continuum models for solid-state dewetting of thin films with anisotropic surface energies. The governing equations of the sharp-interface models belong to a new type of high-order (4th- or 6th-order) geometric evolution partial differential equations about open curve/surface interface tracking problems which include anisotropic surface diffusion flow and contact line migration. Compared to the traditional methods (e.g., marker-particle methods), the proposed PFEM not only has very good accuracy, but also poses very mild restrictions on the numerical stability, and thus it has significant advantages for solving this type of open curve evolution problems with applications in the simulation of solid-state dewetting. Extensive numerical results are reported to demonstrate the accuracy and high efficiency of the proposed PFEM.

Estadiaje local del carcinoma rectal: imágenes de ecografía versus resonancia magnética. Revisión sistemática de la literatura y metaanálisis.

PubMed

Guenaga, Katia F; Otoch, Jose P; Artifon, Everson L A

2016-01-01

New surgical techniques in the treatment of rectal cancer have improved survival mainly by reducing local recurrences. A preoperative staging method is required to accurately identify tumor stage and planning the appropriate treatment. MRI and ERUS are currently being used for the local staging (T stage). In this review, the accuracy of MRI and ERUS with rigid probe was compared against the gold standard of the pathological findings in the resection specimens. Five studies met the inclusion criteria and were included in this meta-analysis. The accuracy was 91.0% to ERUS and 86.8% to MRI (p=0.27). The result has no statistical significance but with pronounced heterogeneity between the included trials as well as other published reviews. We can conclude that there is a clear need for good quality, larger scale and prospective studies.

[Dental arch form reverting by four-point method].

PubMed

Pan, Xiao-Gang; Qian, Yu-Fen; Weng, Si-En; Feng, Qi-Ping; Yu, Quan

2008-04-01

To explore a simple method of reverting individual dental arch form template for wire bending. Individual dental arch form was reverted by four-point method. By defining central point of bracket on bilateral lower second premolar and first molar, certain individual dental arch form could be generated. The arch form generating procedure was then be developed to computer software for printing arch form. Four-point method arch form was evaluated by comparing with direct model measurement on linear and angular parameters. The accuracy and reproducibility were assessed by paired t test and concordance correlation coefficient with Medcalc 9.3 software package. The arch form by four-point method was of good accuracy and reproducibility (linear concordance correlation coefficient was 0.9909 and angular concordance correlation coefficient was 0.8419). The dental arch form reverted by four-point method could reproduce the individual dental arch form.

Mapping advanced argillic alteration zones with ASTER and Hyperion data in the Andes Mountains of Peru

NASA Astrophysics Data System (ADS)

Ramos, Yuddy; Goïta, Kalifa; Péloquin, Stéphane

2016-04-01

This study evaluates Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Hyperion hyperspectral sensor datasets to detect advanced argillic minerals. The spectral signatures of some alteration clay minerals, such as dickite and alunite, have similar absorption features; thus separating them using multispectral satellite images is a complex challenge. However, Hyperion with its fine spectral bands has potential for good separability of features. The Spectral Angle Mapper algorithm was used in this study to map three advanced argillic alteration minerals (alunite, kaolinite, and dickite) in a known alteration zone in the Peruvian Andes. The results from ASTER and Hyperion were analyzed, compared, and validated using a Portable Infrared Mineral Analyzer field spectrometer. The alterations corresponding to kaolinite and alunite were detected with both ASTER and Hyperion (80% to 84% accuracy). However, the dickite mineral was identified only with Hyperion (82% accuracy).

An efficient method for hybrid density functional calculation with spin-orbit coupling

NASA Astrophysics Data System (ADS)

Wang, Maoyuan; Liu, Gui-Bin; Guo, Hong; Yao, Yugui

2018-03-01

In first-principles calculations, hybrid functional is often used to improve accuracy from local exchange correlation functionals. A drawback is that evaluating the hybrid functional needs significantly more computing effort. When spin-orbit coupling (SOC) is taken into account, the non-collinear spin structure increases computing effort by at least eight times. As a result, hybrid functional calculations with SOC are intractable in most cases. In this paper, we present an approximate solution to this problem by developing an efficient method based on a mixed linear combination of atomic orbital (LCAO) scheme. We demonstrate the power of this method using several examples and we show that the results compare very well with those of direct hybrid functional calculations with SOC, yet the method only requires a computing effort similar to that without SOC. The presented technique provides a good balance between computing efficiency and accuracy, and it can be extended to magnetic materials.

Accuracy of Estimating Solar Radiation Pressure for GEO Debris with Tumbling Effect

NASA Astrophysics Data System (ADS)

Chao, Chia-Chun George

2009-03-01

The accuracy of estimating solar radiation pressure for GEO debris is examined and demonstrated, via numerical simulations, by fitting a batch (months) of simulated position vectors. These simulated position vectors are generated from a "truth orbit" with added white noise using high-precision numerical integration tools. After the long-arc fit of the simulated observations (position vectors), one can accurately and reliably determine how close the estimated value of solar radiation pressure is to the truth. Results of this study show that the inherent accuracy in estimating the solar radiation pressure coefficient can be as good as 1% if a long-arc fit span up to 180 days is used and the satellite is not tumbling. The corresponding position prediction accuracy can be as good as, in maximum error, 1 km along in-track, 0.3 km along radial and 0.1 km along cross-track up to 30 days. Similar accuracies can be expected when the object is tumbling as long as the rate of attitude change is different from the orbit rate. Results of this study reveal an important phenomenon that the solar radiation pressure significantly affects the orbit motion when the spin rate is equal to the orbit rate.

Characterization of stacked-crystal PET detector designs for measurement of both TOF and DOI.

PubMed

Schmall, Jeffrey P; Surti, Suleman; Karp, Joel S

2015-05-07

A PET detector with good timing resolution and two-level depth-of-interaction (DOI) discrimination can be constructed using a single-ended readout of scintillator stacks of Lanthanum Bromide (LaBr3), with various Cerium dopant concentrations, including pure Cerium Bromide (CeBr3). The stacked crystal geometry creates a unique signal shape for interactions occurring in each layer, which can be used to identify the DOI, while retaining the inherently good timing properties of LaBr3 and CeBr3. In this work, single pixel elements are used to optimize the choice of scintillator, coupling of layers, and type of photodetector, evaluating the performance using a fast, single-channel photomultiplier tube (PMT) and a single 4 × 4 mm(2) silicon photomultiplier (SiPM). We also introduce a method to quantify and evaluate the DOI discrimination accuracy. From signal shape measurements using fast waveform sampling, we found that in addition to differences in signal rise times, between crystal layers, there were also differences in the signal fall times. A DOI accuracy of 98% was achieved using our classification method for a stacked crystal pair, consisting of a 15 mm long LaBr3(Ce:20%) crystal on top of a 15 mm long CeBr3 crystal, readout using a PMT. A DOI accuracy of 95% was measured with a stack of two, identical, 12 mm long, CeBr3 crystals. The DOI accuracy of this crystal pair was reduced to 91% when using a SiPM for readout. For the stack of two, 12 mm long, CeBr3 crystals, a coincidence timing resolution (average of timing results from the top and bottom layer) of 199 ps was measured using a PMT, and this was improved to 153 ps when using a SiPM. These results show that with stacked LaBr3/CeBr3 scintillators and fast waveform sampling nearly perfect DOI accuracy can be achieved with excellent timing resolution-timing resolution that is only minimally degraded compared to results from a single CeBr3 crystal of comparable length to the stacked crystals. The interface in the stacked crystal geometry itself plays a major role in creating the differences in signal shape and this can be used to construct stacked DOI detectors using the same scintillator type, thereby simplifying and broadening the application of this technique.

Characterization of stacked-crystal PET detector designs for measurement of both TOF and DOI

PubMed Central

Schmall, Jeffrey P; Surti, Suleman; Karp, Joel S

2015-01-01

A PET detector with good timing resolution and two-level depth-of-interaction (DOI) discrimination can be constructed using a single-ended readout of scintillator stacks of Lanthanum Bromide (LaBr3), with various Cerium dopant concentrations, including pure Cerium Bromide (CeBr3). The stacked crystal geometry creates a unique signal shape for interactions occurring in each layer, which can be used to identify the DOI, while retaining the inherently good timing properties of LaBr3 and CeBr3. In this work, single pixel elements are used to optimize the choice of scintillator, coupling of layers, and type of photodetector, evaluating the performance using a fast, single-channel photomultiplier tube (PMT) and a single 4×4 mm2 silicon photomultiplier (SiPM). We also introduce a method to quantify and evaluate the DOI discrimination accuracy. From signal shape measurements using fast waveform sampling, we found that in addition to differences in signal rise times, between crystal layers, there were also differences in the signal fall times. A DOI accuracy of 98% was achieved using our classification method for a stacked crystal pair, consisting of a 15-mm long LaBr3(Ce:20%) crystal on top of a 15-mm long CeBr3 crystal, readout using a PMT. A DOI accuracy of 95% was measured with a stack of two, identical, 12-mm long, CeBr3 crystals. The DOI accuracy of this crystal pair was reduced to 91% when using a SiPM for readout. For the stack of two, 12-mm long, CeBr3 crystals, a coincidence timing resolution (average of timing results from the top and bottom layer) of 199 ps was measured using a PMT, and this was improved to 153 ps when using a SiPM. These results show that with stacked LaBr3/CeBr3 scintillators and fast waveform sampling nearly perfect DOI accuracy can be achieved with excellent timing resolution—timing resolution that is only minimally degraded compared to results from a single CeBr3 crystal of comparable length to the stacked crystals. The interface in the stacked crystal geometry itself plays a major role in creating the differences in signal shape and this can be used to construct stacked DOI detectors using the same scintillator type, thereby simplifying and broadening the application of this technique. PMID:25860172

40 CFR 86.1338-84 - Emission measurement accuracy.

Code of Federal Regulations, 2010 CFR

2010-07-01

... engineering practice dictates that exhaust emission sample analyzer readings below 15 percent of full scale... computers, data loggers, etc., can provide sufficient accuracy and resolution below 15 percent of full scale... spaced points, using good engineering judgement, below 15 percent of full scale are made to ensure the...

40 CFR 86.1338-84 - Emission measurement accuracy.

Code of Federal Regulations, 2013 CFR

2013-07-01

... engineering practice dictates that exhaust emission sample analyzer readings below 15 percent of full scale... computers, data loggers, etc., can provide sufficient accuracy and resolution below 15 percent of full scale... spaced points, using good engineering judgement, below 15 percent of full scale are made to ensure the...

40 CFR 86.1338-84 - Emission measurement accuracy.

Code of Federal Regulations, 2012 CFR

2012-07-01

... engineering practice dictates that exhaust emission sample analyzer readings below 15 percent of full scale... computers, data loggers, etc., can provide sufficient accuracy and resolution below 15 percent of full scale... spaced points, using good engineering judgement, below 15 percent of full scale are made to ensure the...

40 CFR 86.1338-84 - Emission measurement accuracy.

Code of Federal Regulations, 2011 CFR

2011-07-01

... engineering practice dictates that exhaust emission sample analyzer readings below 15 percent of full scale... computers, data loggers, etc., can provide sufficient accuracy and resolution below 15 percent of full scale... spaced points, using good engineering judgement, below 15 percent of full scale are made to ensure the...

Accuracy of magnetic resonance based susceptibility measurements

NASA Astrophysics Data System (ADS)

Erdevig, Hannah E.; Russek, Stephen E.; Carnicka, Slavka; Stupic, Karl F.; Keenan, Kathryn E.

2017-05-01

Magnetic Resonance Imaging (MRI) is increasingly used to map the magnetic susceptibility of tissue to identify cerebral microbleeds associated with traumatic brain injury and pathological iron deposits associated with neurodegenerative diseases such as Parkinson's and Alzheimer's disease. Accurate measurements of susceptibility are important for determining oxygen and iron content in blood vessels and brain tissue for use in noninvasive clinical diagnosis and treatment assessments. Induced magnetic fields with amplitude on the order of 100 nT, can be detected using MRI phase images. The induced field distributions can then be inverted to obtain quantitative susceptibility maps. The focus of this research was to determine the accuracy of MRI-based susceptibility measurements using simple phantom geometries and to compare the susceptibility measurements with magnetometry measurements where SI-traceable standards are available. The susceptibilities of paramagnetic salt solutions in cylindrical containers were measured as a function of orientation relative to the static MRI field. The observed induced fields as a function of orientation of the cylinder were in good agreement with simple models. The MRI susceptibility measurements were compared with SQUID magnetometry using NIST-traceable standards. MRI can accurately measure relative magnetic susceptibilities while SQUID magnetometry measures absolute magnetic susceptibility. Given the accuracy of moment measurements of tissue mimicking samples, and the need to look at small differences in tissue properties, the use of existing NIST standard reference materials to calibrate MRI reference structures is problematic and better reference materials are required.

Quantitative underwater 3D motion analysis using submerged video cameras: accuracy analysis and trajectory reconstruction.

PubMed

Silvatti, Amanda P; Cerveri, Pietro; Telles, Thiago; Dias, Fábio A S; Baroni, Guido; Barros, Ricardo M L

2013-01-01

In this study we aim at investigating the applicability of underwater 3D motion capture based on submerged video cameras in terms of 3D accuracy analysis and trajectory reconstruction. Static points with classical direct linear transform (DLT) solution, a moving wand with bundle adjustment and a moving 2D plate with Zhang's method were considered for camera calibration. As an example of the final application, we reconstructed the hand motion trajectories in different swimming styles and qualitatively compared this with Maglischo's model. Four highly trained male swimmers performed butterfly, breaststroke and freestyle tasks. The middle fingertip trajectories of both hands in the underwater phase were considered. The accuracy (mean absolute error) of the two calibration approaches (wand: 0.96 mm - 2D plate: 0.73 mm) was comparable to out of water results and highly superior to the classical DLT results (9.74 mm). Among all the swimmers, the hands' trajectories of the expert swimmer in the style were almost symmetric and in good agreement with Maglischo's model. The kinematic results highlight symmetry or asymmetry between the two hand sides, intra- and inter-subject variability in terms of the motion patterns and agreement or disagreement with the model. The two outcomes, calibration results and trajectory reconstruction, both move towards the quantitative 3D underwater motion analysis.

Trend analysis of the aerosol optical depth from fusion of MISR and MODIS retrievals over China

NASA Astrophysics Data System (ADS)

Guo, Jing; Gu, Xingfa; Yu, Tao; Cheng, Tianhai; Chen, Hao

2014-03-01

Atmospheric aerosol plays an important role in the climate change though direct and indirect processes. In order to evaluate the effects of aerosols on climate, it is necessary to have a research on their spatial and temporal distributions. Satellite aerosol remote sensing is a developing technology that may provide good temporal sampling and superior spatial coverage to study aerosols. The Moderate Resolution Imaging Spectroradiometer (MODIS) and Multi-angle Imaging Spectroradiometer (MISR) have provided aerosol observations since 2000, with large coverage and high accuracy. However, due to the complex surface, cloud contamination, and aerosol models used in the retrieving process, the uncertainties still exist in current satellite aerosol products. There are several observed differences in comparing the MISR and MODIS AOD data with the AERONET AOD. Combing multiple sensors could reduce uncertainties and improve observational accuracy. The validation results reveal that a better agreement between fusion AOD and AERONET AOD. The results confirm that the fusion AOD values are more accurate than single sensor. We have researched the trend analysis of the aerosol properties over China based on nine-year (2002-2010) fusion data. Compared with trend analysis in Jingjintang and Yangtze River Delta, the accuracy has increased by 5% and 3%, respectively. It is obvious that the increasing trend of the AOD occurred in Yangtze River Delta, where human activities may be the main source of the increasing AOD.

Comparison of 10 single and stepped methods to identify frail older persons in primary care: diagnostic and prognostic accuracy.

PubMed

Sutorius, Fleur L; Hoogendijk, Emiel O; Prins, Bernard A H; van Hout, Hein P J

2016-08-03

Many instruments have been developed to identify frail older adults in primary care. A direct comparison of the accuracy and prevalence of identification methods is rare and most studies ignore the stepped selection typically employed in routine care practice. Also it is unclear whether the various methods select persons with different characteristics. We aimed to estimate the accuracy of 10 single and stepped methods to identify frailty in older adults and to predict adverse health outcomes. In addition, the methods were compared on their prevalence of the identified frail persons and on the characteristics of persons identified. The Groningen Frailty Indicator (GFI), the PRISMA-7, polypharmacy, the clinical judgment of the general practitioner (GP), the self-rated health of the older adult, the Edmonton Frail Scale (EFS), the Identification Seniors At Risk Primary Care (ISAR PC), the Frailty Index (FI), the InterRAI screener and gait speed were compared to three measures: two reference standards (the clinical judgment of a multidisciplinary expert panel and Fried's frailty criteria) and 6-years mortality or long term care admission. Data were used from the Dutch Identification of Frail Elderly Study, consisting of 102 people aged 65 and over from a primary care practice in Amsterdam. Frail older adults were oversampled. The accuracy of each instrument and several stepped strategies was estimated by calculating the area under the ROC-curve. Prevalence rates of frailty ranged from 14.8 to 52.9 %. The accuracy for recommended cut off values ranged from poor (AUC = 0.556 ISAR-PC) to good (AUC = 0.865 gait speed). PRISMA-7 performed best over two reference standards, GP predicted adversities best. Stepped strategies resulted in lower prevalence rates and accuracy. Persons selected by the different instruments varied greatly in age, IADL dependency, receiving homecare and mood. We found huge differences between methods to identify frail persons in prevalence, accuracy and in characteristics of persons they select. A necessary next step is to find out which frail persons can benefit from intervention before case finding programs are implemented. Further evidence is needed to guide this emerging clinical field.

Evaluation of reliability and validity of three dental color-matching devices.

PubMed

Tsiliagkou, Aikaterini; Diamantopoulou, Sofia; Papazoglou, Efstratios; Kakaboura, Afrodite

2016-01-01

To assess the repeatability and accuracy of three dental color-matching devices under standardized and freehand measurement conditions. Two shade guides (Vita Classical A1-D4, Vita; and Vita Toothguide 3D-Master, Vita), and three color-matching devices (Easyshade, Vita; SpectroShade, MHT Optic Research; and ShadeVision, X-Rite) were used. Five shade tabs were selected from the Vita Classical A1-D4 (A2, A3.5, B1, C4, D3), and five from the Vita Toothguide 3D-Master (1M1, 2R1.5, 3M2, 4L2.5, 5M3) shade guides. Each shade tab was recorded 15 continuous, repeated times with each device under two different measurement conditions (standardized, and freehand). Both qualitative (color shade) and quantitative (L, a, and b) color characteristics were recorded. The color difference (ΔE) of each recorded value with the known values of the shade tab was calculated. The repeatability of each device was evaluated by the coefficient of variance. The accuracy of each device was determined by comparing the recorded values with the known values of the reference shade tab (one sample t test; α = 0.05). The agreement between the recorded shade and the reference shade tab was calculated. The influence of the parameters (devices and conditions) on the parameter ΔE was investigated (two-way ANOVA). Comparison of the devices was performed with Bonferroni pairwise post-hoc analysis. Under standardized conditions, repeatability of all three devices was very good, except for ShadeVision with Vita Classical A1-D4. Accuracy ranged from good to fair, depending on the device and the shade guide. Under freehand conditions, repeatability and accuracy for Easyshade and ShadeVision were negatively influenced, but not for SpectroShade, regardless of the shade guide. Based on the total of the color parameters assessed per device, SpectroShade was the most reliable of the three color-matching devices studied.

Meta-analysis of stratus OCT glaucoma diagnostic accuracy.

PubMed

Chen, Hsin-Yi; Chang, Yue-Cune

2014-09-01

To evaluate the diagnostic accuracy of glaucoma in different stages, different types of glaucoma, and different ethnic groups using Stratus optical coherence tomography (OCT). We searched MEDLINE to identify available articles on diagnostic accuracy of glaucoma published between January 2004 and December 2011. A PubMed (National Center for Biotechnology Information) search using medical subject headings and keywords was executed using the following terms: "diagnostic accuracy" or "receiver operator characteristic" or "area under curve" or "AUC" and "Stratus OCT" and "glaucoma." The search was subsequently limited to publications in English. The area under a receiver operator characteristic (AUC) curve was used to measure the diagnostic performance. A random-effects model was used to estimate the pooled AUC value of the 17 parameters (average retinal nerve fiber layer thickness, temporal quadrant, superior quadrant, nasal quadrant, inferior quadrant, and 1 to 12 o'clock). Meta-regression analysis was used to check the significance of some important factors: (1) glaucoma severity (five stages), (2) glaucoma types (four types), and (3) ethnicity (four categories). The orders of accuracy among those parameters were as follows: average > inferior > superior > 7 o'clock > 6 o'clock > 11 o'clock > 12 o'clock > 1 o'clock > 5 o'clock > nasal > temporal > 2 o'clock > 10 o'clock > 8 o'clock > 9 o'clock > 4 o'clock > 3 o'clock. After adjusting for the effects of age, glaucoma severity, glaucoma types, and ethnicity, the average retinal nerve fiber layer thickness provided highest accuracy compared with the other parameters of OCT. The diagnostic accuracy in Asian populations was significantly lower than that in whites and the other two ethnic types. Stratus OCT demonstrated good diagnostic capability in differentiating glaucomatous from normal eyes. However, we should be more cautious in applying this instrument in Asian groups in glaucoma management.

Diagnostic Accuracy Assessment of Sensititre and Agar Disk Diffusion for Determining Antimicrobial Resistance Profiles of Bovine Clinical Mastitis Pathogens▿

PubMed Central

Saini, V.; Riekerink, R. G. M. Olde; McClure, J. T.; Barkema, H. W.

2011-01-01

Determining the accuracy and precision of a measuring instrument is pertinent in antimicrobial susceptibility testing. This study was conducted to predict the diagnostic accuracy of the Sensititre MIC mastitis panel (Sensititre) and agar disk diffusion (ADD) method with reference to the manual broth microdilution test method for antimicrobial resistance profiling of Escherichia coli (n = 156), Staphylococcus aureus (n = 154), streptococcal (n = 116), and enterococcal (n = 31) bovine clinical mastitis isolates. The activities of ampicillin, ceftiofur, cephalothin, erythromycin, oxacillin, penicillin, the penicillin-novobiocin combination, pirlimycin, and tetracycline were tested against the isolates. Diagnostic accuracy was determined by estimating the area under the receiver operating characteristic curve; intertest essential and categorical agreements were determined as well. Sensititre and the ADD method demonstrated moderate to highly accurate (71 to 99%) and moderate to perfect (71 to 100%) predictive accuracies for 74 and 76% of the isolate-antimicrobial MIC combinations, respectively. However, the diagnostic accuracy was low for S. aureus-ceftiofur/oxacillin combinations and other streptococcus-ampicillin combinations by either testing method. Essential agreement between Sensititre automatic MIC readings and MIC readings obtained by the broth microdilution test method was 87%. Essential agreement between Sensititre automatic and manual MIC reading methods was 97%. Furthermore, the ADD test method and Sensititre MIC method exhibited 92 and 91% categorical agreement (sensitive, intermediate, resistant) of results, respectively, compared with the reference method. However, both methods demonstrated lower agreement for E. coli-ampicillin/cephalothin combinations than for Gram-positive isolates. In conclusion, the Sensititre and ADD methods had moderate to high diagnostic accuracy and very good essential and categorical agreement for most udder pathogen-antimicrobial combinations and can be readily employed in veterinary diagnostic laboratories. PMID:21270215

Accuracy and precision evaluation of seven self-monitoring blood glucose systems.

PubMed

Kuo, Chih-Yi; Hsu, Cheng-Teng; Ho, Cheng-Shiao; Su, Ting-En; Wu, Ming-Hsun; Wang, Chau-Jong

2011-05-01

Self-monitoring blood glucose (SMBG) systems play a critical role in management of diabetes. SMBG systems should at least meet the minimal requirement of the World Health Organization's ISO 15197:2003. For tight glycemic control, a tighter accuracy requirement is needed. Seven SMBG systems were evaluated for accuracy and precision: Bionime Rightest(™) GM550 (Bionime Corp., Dali City, Taiwan), Accu-Chek(®) Performa (Roche Diagnostics, Indianapolis, IN), OneTouch(®) Ultra(®)2 (LifeScan Inc., Milpitas, CA), MediSense(®) Optium(™) Xceed (Abbott Diabetes Care Inc., Alameda, CA), Medisafe (TERUMO Corp., Tokyo, Japan), Fora(®) TD4227 (Taidac Technology Corp., Wugu Township, Taiwan), and Ascensia Contour(®) (Bayer HealthCare LLC, Mishawaka, IN). The 107 participants (44 men and 63 women) were between 23 and 91 years old. The analytical results of seven SMBG systems were compared with those of plasma analyzed with the hexokinase method (Olympus AU640, Olympus America Inc., Center Valley, PA). The imprecision of the seven blood glucose meters ranged from 1.1% to 4.7%. Three of the seven blood glucose meters (42.9%) fulfilled the minimum accuracy criteria of ISO 15197:2003. The mean absolute relative error value for each blood glucose meter was calculated and ranged from 6.5% to 12.0%. More than 40% of evaluated SMBG systems meet the minimal accuracy criteria requirement of ISO 15197:2003. However, considering tighter criteria for accuracy of ±15%, only the Bionime Rightest GM550 meets this requirement. Because SMBG systems play a critical role in management of diabetes, manufacturers have to strive to improve accuracy and precision and to ensure the good quality of blood glucose meters and test strips.

Validation of deformable image registration algorithms on CT images of ex vivo porcine bladders with fiducial markers

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

Wognum, S., E-mail: s.wognum@gmail.com; Heethuis, S. E.; Bel, A.

2014-07-15

Purpose: The spatial accuracy of deformable image registration (DIR) is important in the implementation of image guided adaptive radiotherapy techniques for cancer in the pelvic region. Validation of algorithms is best performed on phantoms with fiducial markers undergoing controlled large deformations. Excised porcine bladders, exhibiting similar filling and voiding behavior as human bladders, provide such an environment. The aim of this study was to determine the spatial accuracy of different DIR algorithms on CT images ofex vivo porcine bladders with radiopaque fiducial markers applied to the outer surface, for a range of bladder volumes, using various accuracy metrics. Methods: Fivemore » excised porcine bladders with a grid of 30–40 radiopaque fiducial markers attached to the outer wall were suspended inside a water-filled phantom. The bladder was filled with a controlled amount of water with added contrast medium for a range of filling volumes (100–400 ml in steps of 50 ml) using a luer lock syringe, and CT scans were acquired at each filling volume. DIR was performed for each data set, with the 100 ml bladder as the reference image. Six intensity-based algorithms (optical flow or demons-based) implemented in theMATLAB platform DIRART, a b-spline algorithm implemented in the commercial software package VelocityAI, and a structure-based algorithm (Symmetric Thin Plate Spline Robust Point Matching) were validated, using adequate parameter settings according to values previously published. The resulting deformation vector field from each registration was applied to the contoured bladder structures and to the marker coordinates for spatial error calculation. The quality of the algorithms was assessed by comparing the different error metrics across the different algorithms, and by comparing the effect of deformation magnitude (bladder volume difference) per algorithm, using the Independent Samples Kruskal-Wallis test. Results: The authors found good structure accuracy without dependency on bladder volume difference for all but one algorithm, and with the best result for the structure-based algorithm. Spatial accuracy as assessed from marker errors was disappointing for all algorithms, especially for large volume differences, implying that the deformations described by the registration did not represent anatomically correct deformations. The structure-based algorithm performed the best in terms of marker error for the large volume difference (100–400 ml). In general, for the small volume difference (100–150 ml) the algorithms performed relatively similarly. The structure-based algorithm exhibited the best balance in performance between small and large volume differences, and among the intensity-based algorithms, the algorithm implemented in VelocityAI exhibited the best balance. Conclusions: Validation of multiple DIR algorithms on a novel physiological bladder phantom revealed that the structure accuracy was good for most algorithms, but that the spatial accuracy as assessed from markers was low for all algorithms, especially for large deformations. Hence, many of the available algorithms exhibit sufficient accuracy for contour propagation purposes, but possibly not for accurate dose accumulation.« less

Comparison between MDCT and Grayscale IVUS in a Quantitative Analysis of Coronary Lumen in Segments with or without Atherosclerotic Plaques

PubMed Central

Falcão, João L. A. A.; Falcão, Breno A. A.; Gurudevan, Swaminatha V.; Campos, Carlos M.; Silva, Expedito R.; Kalil-Filho, Roberto; Rochitte, Carlos E.; Shiozaki, Afonso A.; Coelho-Filho, Otavio R.; Lemos, Pedro A.

2015-01-01

Background The diagnostic accuracy of 64-slice MDCT in comparison with IVUS has been poorly described and is mainly restricted to reports analyzing segments with documented atherosclerotic plaques. Objectives We compared 64-slice multidetector computed tomography (MDCT) with gray scale intravascular ultrasound (IVUS) for the evaluation of coronary lumen dimensions in the context of a comprehensive analysis, including segments with absent or mild disease. Methods The 64-slice MDCT was performed within 72 h before the IVUS imaging, which was obtained for at least one coronary, regardless of the presence of luminal stenosis at angiography. A total of 21 patients were included, with 70 imaged vessels (total length 114.6 ± 38.3 mm per patient). A coronary plaque was diagnosed in segments with plaque burden > 40%. Results At patient, vessel, and segment levels, average lumen area, minimal lumen area, and minimal lumen diameter were highly correlated between IVUS and 64-slice MDCT (p < 0.01). However, 64-slice MDCT tended to underestimate the lumen size with a relatively wide dispersion of the differences. The comparison between 64-slice MDCT and IVUS lumen measurements was not substantially affected by the presence or absence of an underlying plaque. In addition, 64-slice MDCT showed good global accuracy for the detection of IVUS parameters associated with flow-limiting lesions. Conclusions In a comprehensive, multi-territory, and whole-artery analysis, the assessment of coronary lumen by 64-slice MDCT compared with coronary IVUS showed a good overall diagnostic ability, regardless of the presence or absence of underlying atherosclerotic plaques. PMID:25993595

A global comparative evaluation of commercial immunochromatographic rapid diagnostic tests for visceral leishmaniasis.

PubMed

Cunningham, Jane; Hasker, Epco; Das, Pradeep; El Safi, Sayda; Goto, Hiro; Mondal, Dinesh; Mbuchi, Margaret; Mukhtar, Maowia; Rabello, Ana; Rijal, Suman; Sundar, Shyam; Wasunna, Monique; Adams, Emily; Menten, Joris; Peeling, Rosanna; Boelaert, Marleen

2012-11-15

Poor access to diagnosis stymies control of visceral leishmaniasis (VL). Antibody-detecting rapid diagnostic tests (RDTs) can be performed in peripheral health settings. However, there are many brands available and published reports of variable accuracy. Commercial VL RDTs containing bound rK39 or rKE16 antigen were evaluated using archived human sera from confirmed VL cases (n = 750) and endemic non-VL controls (n = 754) in the Indian subcontinent (ISC), Brazil, and East Africa to assess sensitivity and specificity with 95% confidence intervals. A subset of RDTs were also evaluated after 60 days' heat incubation (37°C, 45°C). Interlot and interobserver variability was assessed. All test brands performed well against ISC panels (sensitivity range, 92.8%-100%; specificity range, 96%-100%); however, sensitivity was lower against Brazil and East African panels (61.5%-91% and 36.8%-87.2%, respectively). Specificity was consistently > 95% in Brazil and ranged between 90.8% and 98% in East Africa. Performance of some products was adversely affected by high temperatures. Agreement between lots and readers was good to excellent (κ > 0.73-0.99). Diagnostic accuracy of VL RDTs varies between the major endemic regions. Many tests performed well and showed good heat stability in the ISC; however, reduced sensitivity against Brazilian and East African panels suggests that in these regions, used alone, several RDTs are inadequate for excluding a VL diagnosis. More research is needed to assess ease of use and to compare performance using whole blood instead of serum and in patients coinfected with human immunodeficiency virus.

Laboratory-based performance evaluation of PIMA CD4+ T-lymphocyte count point-of-care by lay-counselors in Kenya.

PubMed

Zeh, Clement; Rose, Charles E; Inzaule, Seth; Desai, Mitesh A; Otieno, Fredrick; Humwa, Felix; Akoth, Benta; Omolo, Paul; Chen, Robert T; Kebede, Yenew; Samandari, Taraz

2017-09-01

CD4+ T-lymphocyte count testing at the point-of-care (POC) may improve linkage to care of persons diagnosed with HIV-1 infection, but the accuracy of POC devices when operated by lay-counselors in the era of task-shifting is unknown. We examined the accuracy of Alere's Pima™ POC device on both capillary and venous blood when performed by lay-counselors and laboratory technicians. In Phase I, we compared the perfomance of POC against FACSCalibur™ for 280 venous specimens by laboratory technicians. In Phase II we compared POC performance by lay-counselors versus laboratory technicians using 147 paired capillary and venous specimens, and compared these to FACSCalibur™. Statistical analyses included Bland-Altman analyses, concordance correlation coefficient, sensitivity, and specificity at treatment eligibility thresholds of 200, 350, and 500cells/μl. Phase I: POC sensitivity and specificity were 93.0% and 84.1% at 500cells/μl, respectively. Phase II: Good agreement was observed for venous POC results from both lay-counselors (concordance correlation coefficient (CCC)=0.873, bias -86.4cells/μl) and laboratory technicians (CCC=0.920, bias -65.7cells/μl). Capillary POC had good correlation: lay-counselors (CCC=0.902, bias -71.2cells/μl), laboratory technicians (CCC=0.918, bias -63.0cells/μl). Misclassification at the 500 cells/μl threshold for venous blood was 13.6% and 10.2% for lay-counselors and laboratory technicians and 12.2% for capillary blood in both groups. POC tended to under-classify the CD4 values with increasingly negative bias at higher CD4 values. Pima™ results were comparable to FACSCalibur™ for both venous and capillary specimens when operated by lay-counselors. POC CD4 testing has the potential to improve linkage to HIV care without burdening laboratory technicians in resource-limited settings. Published by Elsevier B.V.

Comparing the ISO-recommended and the cumulative data-reduction algorithms in S-on-1 laser damage test by a reverse approach method

NASA Astrophysics Data System (ADS)

Zorila, Alexandru; Stratan, Aurel; Nemes, George

2018-01-01

We compare the ISO-recommended (the standard) data-reduction algorithm used to determine the surface laser-induced damage threshold of optical materials by the S-on-1 test with two newly suggested algorithms, both named "cumulative" algorithms/methods, a regular one and a limit-case one, intended to perform in some respects better than the standard one. To avoid additional errors due to real experiments, a simulated test is performed, named the reverse approach. This approach simulates the real damage experiments, by generating artificial test-data of damaged and non-damaged sites, based on an assumed, known damage threshold fluence of the target and on a given probability distribution function to induce the damage. In this work, a database of 12 sets of test-data containing both damaged and non-damaged sites was generated by using four different reverse techniques and by assuming three specific damage probability distribution functions. The same value for the threshold fluence was assumed, and a Gaussian fluence distribution on each irradiated site was considered, as usual for the S-on-1 test. Each of the test-data was independently processed by the standard and by the two cumulative data-reduction algorithms, the resulting fitted probability distributions were compared with the initially assumed probability distribution functions, and the quantities used to compare these algorithms were determined. These quantities characterize the accuracy and the precision in determining the damage threshold and the goodness of fit of the damage probability curves. The results indicate that the accuracy in determining the absolute damage threshold is best for the ISO-recommended method, the precision is best for the limit-case of the cumulative method, and the goodness of fit estimator (adjusted R-squared) is almost the same for all three algorithms.

Satellite observed salinity distributions at high latitudes in the Northern Hemisphere: A comparison of four products

NASA Astrophysics Data System (ADS)

Garcia-Eidell, Cynthia; Comiso, Josefino C.; Dinnat, Emmanuel; Brucker, Ludovic

2017-09-01

Global surface ocean salinity measurements have been available since the launch of SMOS in 2009 and coverage was further enhanced with the launch of Aquarius in 2011. In the polar regions where spatial and temporal changes in sea surface salinity (SSS) are deemed important, the data have not been as robustly validated because of the paucity of in situ measurements. This study presents a comparison of four SSS products in the ice-free Arctic region, three using Aquarius data and one using SMOS data. The accuracy of each product is assessed through comparative analysis with ship and other in situ measurements. Results indicate RMS errors ranging between 0.33 and 0.89 psu. Overall, the four products show generally good consistency in spatial distribution with the Atlantic side being more saline than the Pacific side. A good agreement between the ship and satellite measurements was also observed in the low salinity regions in the Arctic Ocean, where SSS in situ measurements are usually sparse, at the end of summer melt seasons. Some discrepancies including biases of about 1 psu between the products in spatial and temporal distribution are observed. These are due in part to differences in retrieval techniques, geophysical filtering, and sea ice and land masks. The monthly SSS retrievals in the Arctic from 2011 to 2015 showed variations (within ˜1 psu) consistent with effects of sea ice seasonal cycles. This study indicates that spaceborne observations capture the seasonality and interannual variability of SSS in the Arctic with reasonably good accuracy.

Identification of residual breast carcinoma following neoadjuvant chemotherapy: diffusion-weighted imaging--comparison with contrast-enhanced MR imaging and pathologic findings.

PubMed

Woodhams, Reiko; Kakita, Satoko; Hata, Hirofumi; Iwabuchi, Keiichi; Kuranami, Masaru; Gautam, Shiva; Hatabu, Hiroto; Kan, Shinichi; Mountford, Carolyn

2010-02-01

To compare the capability of diffusion-weighted (DW) and contrast material-enhanced magnetic resonance (MR) imaging to provide diagnostic information on residual breast cancers following neoadjuvant chemotherapy and to assess apparent diffusion coefficients (ADCs) of the carcinoma prior to neoadjuvant chemotherapy to determine if the method could help predict response to chemotherapy. Institutional review board approval and informed consent were obtained. Three hundred ninety-eight patients underwent MR imaging of the breast, including DW MR (b values, 0 and 1500 sec/mm(2)) and contrast-enhanced MR imaging. Of these, the contralateral breast in 73 women was used as a control. Seventy-two patients with 73 lesions with malignant disease were treated by using neoadjuvant chemotherapy and were examined for residual disease following therapy. Three were excluded because of prolonged intervals between final MR imaging and surgery. Thus, 69 patients (70 lesions) with DW and contrast-enhanced MR imaging results were compared with postoperative histopathologic findings. The ADCs of the carcinoma prior to neoadjuvant chemotherapy were calculated for each patient, and those with complete response and residual disease were compared. The accuracy for depicting residual tumor was 96% for DW MR imaging, compared with an accuracy of 89% for contrast-enhanced MR imaging (P = .06). There was no significant difference in prechemotherapy ADCs between pathologic complete response cases and those with residual disease. DW MR imaging had at least as good of accuracy as did contrast-enhanced MR imaging for monitoring neoadjuvant chemotherapy. The ADCs prior to chemotherapy did not predict response to chemotherapy. The use of DW imaging to visualize residual breast cancer without the need for contrast medium could be advantageous in women with impaired renal function. (c) RSNA, 2010

Simplified signal processing for impedance spectroscopy with spectrally sparse sequences

NASA Astrophysics Data System (ADS)

Annus, P.; Land, R.; Reidla, M.; Ojarand, J.; Mughal, Y.; Min, M.

2013-04-01

Classical method for measurement of the electrical bio-impedance involves excitation with sinusoidal waveform. Sinusoidal excitation at fixed frequency points enables wide variety of signal processing options, most general of them being Fourier transform. Multiplication with two quadrature waveforms at desired frequency could be easily accomplished both in analogue and in digital domains, even simplest quadrature square waves can be considered, which reduces signal processing task in analogue domain to synchronous switching followed by low pass filter, and in digital domain requires only additions. So called spectrally sparse excitation sequences (SSS), which have been recently introduced into bio-impedance measurement domain, are very reasonable choice when simultaneous multifrequency excitation is required. They have many good properties, such as ease of generation and good crest factor compared to similar multisinusoids. Typically, the usage of discrete or fast Fourier transform in signal processing step is considered so far. Usage of simplified methods nevertheless would reduce computational burden, and enable simpler, less costly and less energy hungry signal processing platforms. Accuracy of the measurement with SSS excitation when using different waveforms for quadrature demodulation will be compared in order to evaluate the feasibility of the simplified signal processing. Sigma delta modulated sinusoid (binary signal) is considered to be a good alternative for a synchronous demodulation.

Uncertainty of OpenStreetMap data for the road network in Cyprus

NASA Astrophysics Data System (ADS)

Demetriou, Demetris

2016-08-01

Volunteered geographic information (VGI) refers to the geographic data compiled and created by individuals which are rendered on the Internet through specific web-based tools for diverse areas of interest. One of the most well-known VGI projects is the OpenStreetMap (OSM) that provides worldwide free geospatial data representing a variety of features. A critical issue for all VGI initiatives is the quality of the information offered. Thus, this report looks into the uncertainty of the OSM dataset for the main road network in Cyprus. The evaluation is based on three basic quality standards, namely positional accuracy, completeness and attribute accuracy. The work has been carried out by employing the Model Builder of ArcGIS which facilitated the comparison between the OSM data and the authoritative data provided by the Public Works Department (PWD). Findings showed that the positional accuracy increases with the hierarchical level of a road, it varies per administrative District and around 70% of the roads have a positional accuracy within 6m compared to the reference dataset. Completeness in terms of road length difference is around 25% for three out of four road categories examined and road name completeness is 100% and around 40% for higher and lower level roads, respectively. Attribute accuracy focusing on road name is very high for all levels of roads. These outputs indicate that OSM data are good enough if they fit for the purpose of use. Furthermore, the study revealed some weaknesses of the methods used for calculating the positional accuracy, suggesting the need for methodological improvements.

Is cone beam computed tomography accurate for postoperative evaluation of implants? An in vitro study.

PubMed

Vidor, Michele Machado; Liedke, Gabriela Salatino; Fontana, Mathias Pante; da Silveira, Heraldo Luis Dias; Arus, Nadia Assein; Lemos, André; Vizzotto, Mariana Boessio

2017-11-01

The aim of this study was to evaluate the accuracy of cone beam computed tomography (CBCT) for evaluation of the bone-implant interface in comparison with periapical radiography. Titanium implants were inserted in 74 bovine rib blocks in intimate contact with bone walls and with a gap of 0.125 mm (simulating failure in the osseointegration process). Periapical radiographs were taken with conventional film, and CBCT scans were acquired with i-CAT (0.2 mm and 0.125 mm voxel) and Kodak (0.2 mm and 0.076 mm voxel) units. Three examiners evaluated the images using a 5-point scale. Diagnostic accuracy was analyzed through sensitivity, specificity, and the area under the receiver operating characteristic (ROC) curve (AUC) with 95% confidence intervals (CIs). Intra- and interexaminer agreements were analyzed through Kendall's concordance test. Intra- and interexaminer agreements showed satisfactory results. The greatest accuracy was observed with conventional radiography (AUC = 0.963; CI 95% = 0.891-0.993). I-CAT 0.125-mm images showed good accuracy (AUC = 0.885; CI 95% = 0.790-0.947), with no significant difference compared with conventional radiography. Kodak images had high specificity and low sensitivity, presenting more false-negative results. Conventional radiography showed the highest accuracy for assessment of the bone-implant interface. However, CBCT (i-CAT; 0.125-mm voxel), if available or if performed for preoperative assessment of another implant site, may provide similar accuracy. Copyright © 2017 Elsevier Inc. All rights reserved.

Accuracy of ultrasound-guided nerve blocks of the cervical zygapophysial joints.

PubMed

Siegenthaler, Andreas; Mlekusch, Sabine; Trelle, Sven; Schliessbach, Juerg; Curatolo, Michele; Eichenberger, Urs

2012-08-01

Cervical zygapophysial joint nerve blocks typically are performed with fluoroscopic needle guidance. Descriptions of ultrasound-guided block of these nerves are available, but only one small study compared ultrasound with fluoroscopy, and only for the third occipital nerve. To evaluate the potential usefulness of ultrasound-guidance in clinical practice, studies that determine the accuracy of this technique using a validated control are essential. The aim of this study was to determine the accuracy of ultrasound-guided nerve blocks of the cervical zygapophysial joints using fluoroscopy as control. Sixty volunteers were studied. Ultrasound-imaging was used to place the needle to the bony target of cervical zygapophysial joint nerve blocks. The levels of needle placement were determined randomly (three levels per volunteer). After ultrasound-guided needle placement and application of 0.2 ml contrast dye, fluoroscopic imaging was performed for later evaluation by a blinded pain physician and considered as gold standard. Raw agreement, chance-corrected agreement κ, and chance-independent agreement Φ between the ultrasound-guided placement and the assessment using fluoroscopy were calculated to quantify accuracy. One hundred eighty needles were placed in 60 volunteers. Raw agreement was 87% (95% CI 81-91%), κ was 0.74 (0.64-0.83), and Φ 0.99 (0.99-0.99). Accuracy varied significantly between the different cervical nerves: it was low for the C7 medial branch, whereas all other levels showed very good accuracy. Ultrasound-imaging is an accurate technique for performing cervical zygapophysial joint nerve blocks in volunteers, except for the medial branch blocks of C7.

Recursive feature selection with significant variables of support vectors.

PubMed

Tsai, Chen-An; Huang, Chien-Hsun; Chang, Ching-Wei; Chen, Chun-Houh

2012-01-01

The development of DNA microarray makes researchers screen thousands of genes simultaneously and it also helps determine high- and low-expression level genes in normal and disease tissues. Selecting relevant genes for cancer classification is an important issue. Most of the gene selection methods use univariate ranking criteria and arbitrarily choose a threshold to choose genes. However, the parameter setting may not be compatible to the selected classification algorithms. In this paper, we propose a new gene selection method (SVM-t) based on the use of t-statistics embedded in support vector machine. We compared the performance to two similar SVM-based methods: SVM recursive feature elimination (SVMRFE) and recursive support vector machine (RSVM). The three methods were compared based on extensive simulation experiments and analyses of two published microarray datasets. In the simulation experiments, we found that the proposed method is more robust in selecting informative genes than SVMRFE and RSVM and capable to attain good classification performance when the variations of informative and noninformative genes are different. In the analysis of two microarray datasets, the proposed method yields better performance in identifying fewer genes with good prediction accuracy, compared to SVMRFE and RSVM.

Evaluation of trade influence on economic growth rate by computational intelligence approach

NASA Astrophysics Data System (ADS)

Sokolov-Mladenović, Svetlana; Milovančević, Milos; Mladenović, Igor

2017-01-01

In this study was analyzed the influence of trade parameters on the economic growth forecasting accuracy. Computational intelligence method was used for the analyzing since the method can handle highly nonlinear data. It is known that the economic growth could be modeled based on the different trade parameters. In this study five input parameters were considered. These input parameters were: trade in services, exports of goods and services, imports of goods and services, trade and merchandise trade. All these parameters were calculated as added percentages in gross domestic product (GDP). The main goal was to select which parameters are the most impactful on the economic growth percentage. GDP was used as economic growth indicator. Results show that the imports of goods and services has the highest influence on the economic growth forecasting accuracy.

Dipyridamole stress myocardial perfusion by computed tomography in patients with left bundle branch block.

PubMed

Cabeda, Estêvan Vieira; Falcão, Andréa Maria Gomes; Soares, José; Rochitte, Carlos Eduardo; Nomura, César Higa; Ávila, Luiz Francisco Rodrigues; Parga, José Rodrigues

2015-12-01

Functional tests have limited accuracy for identifying myocardial ischemia in patients with left bundle branch block (LBBB). To assess the diagnostic accuracy of dipyridamole-stress myocardial computed tomography perfusion (CTP) by 320-detector CT in patients with LBBB using invasive quantitative coronary angiography (QCA) (stenosis ≥ 70%) as reference; to investigate the advantage of adding CTP to coronary computed tomography angiography (CTA) and compare the results with those of single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy. Thirty patients with LBBB who had undergone SPECT for the investigation of coronary artery disease were referred for stress tomography. Independent examiners performed per-patient and per-coronary territory assessments. All patients gave written informed consent to participate in the study that was approved by the institution's ethics committee. The patients' mean age was 62 ± 10 years. The mean dose of radiation for the tomography protocol was 9.3 ± 4.6 mSv. With regard to CTP, the per-patient values for sensitivity, specificity, positive and negative predictive values, and accuracy were 86%, 81%, 80%, 87%, and 83%, respectively (p = 0.001). The per-territory values were 63%, 86%, 65%, 84%, and 79%, respectively (p < 0.001). In both analyses, the addition of CTP to CTA achieved higher diagnostic accuracy for detecting myocardial ischemia than SPECT (p < 0.001). The use of the stress tomography protocol is feasible and has good diagnostic accuracy for assessing myocardial ischemia in patients with LBBB.

Inter-arch digital model vs. manual cast measurements: Accuracy and reliability.

PubMed

Kiviahde, Heikki; Bukovac, Lea; Jussila, Päivi; Pesonen, Paula; Sipilä, Kirsi; Raustia, Aune; Pirttiniemi, Pertti

2017-06-28

The purpose of this study was to evaluate the accuracy and reliability of inter-arch measurements using digital dental models and conventional dental casts. Thirty sets of dental casts with permanent dentition were examined. Manual measurements were done with a digital caliper directly on the dental casts, and digital measurements were made on 3D models by two independent examiners. Intra-class correlation coefficients (ICC), a paired sample t-test or Wilcoxon signed-rank test, and Bland-Altman plots were used to evaluate intra- and inter-examiner error and to determine the accuracy and reliability of the measurements. The ICC values were generally good for manual and excellent for digital measurements. The Bland-Altman plots of all the measurements showed good agreement between the manual and digital methods and excellent inter-examiner agreement using the digital method. Inter-arch occlusal measurements on digital models are accurate and reliable and are superior to manual measurements.

Estimating population genetic parameters and comparing model goodness-of-fit using DNA sequences with error

PubMed Central

Liu, Xiaoming; Fu, Yun-Xin; Maxwell, Taylor J.; Boerwinkle, Eric

2010-01-01

It is known that sequencing error can bias estimation of evolutionary or population genetic parameters. This problem is more prominent in deep resequencing studies because of their large sample size n, and a higher probability of error at each nucleotide site. We propose a new method based on the composite likelihood of the observed SNP configurations to infer population mutation rate θ = 4Neμ, population exponential growth rate R, and error rate ɛ, simultaneously. Using simulation, we show the combined effects of the parameters, θ, n, ɛ, and R on the accuracy of parameter estimation. We compared our maximum composite likelihood estimator (MCLE) of θ with other θ estimators that take into account the error. The results show the MCLE performs well when the sample size is large or the error rate is high. Using parametric bootstrap, composite likelihood can also be used as a statistic for testing the model goodness-of-fit of the observed DNA sequences. The MCLE method is applied to sequence data on the ANGPTL4 gene in 1832 African American and 1045 European American individuals. PMID:19952140

SA36. Atypical Memory Structure Related to Recollective Ability

PubMed Central

Greenland-White, Sarah; Niendam, Tara

2017-01-01

Abstract Background: People with schizophrenia have impaired recognition memory and disproportionate recollection rather than familiarity deficits. This pattern also occurs in individuals with early psychosis (EP) and those at clinical high risk (CHR; Ragland et al., 2016). Additionally, these groups show atypical relationships between different memory processes, with patients demonstrating a stronger reliance on familiarity to support recognition accuracy. However, it is unclear whether these group differences represent a compensatory “trade-off” in memory strategies, whereby patients adopt an overreliance on familiarity to compensate for impaired recollection. We examined data from the Relational and Item-Specific memory task (RiSE) in healthy control (HC), EP and CHR participants, and contrasted subgroups with and without prominent recollection impairments. Interrelations between these memory processes (accuracy, recollection, and familiarity) were examined with Structural Equation Modeling (SEM). Methods: A total of 181 individuals (57 HC, 101 EP, and 21 CHR) completed the RiSE. Measures of recognition accuracy, familiarity, and recollection were computed. We divided the patient group into those with poor recollection (overall d’ recognition accuracy < 1.5, n = 52) and those with good recollection (overall d’ recollection accuracy ≥ 1.5, n = 70). SEM was used to investigate the pattern of memory relationships between HC and patient groups as well as between patients with good versus bad recollection. Results: Recollection and familiarity were negatively correlated in the HC group (r = −.467, P < .01) and in the patient group, though more weakly (r = −.288,P < .05). Improved recollection was correlated with overall improvement in recognition accuracy for both the groups (HC r = .771, P < .01; r = .753, P < .01). Improved familiarity was associated with higher recognition accuracy in the patient group only (.361, P < .01). Moreover, patients with poor recollection showed a stronger association (Fisher’s Z = 2.58, P < .01) between familiarity performance and recognition accuracy (.718, P < .01) than patients with good recollection performance (.396, P < .01). Conclusion: Results suggest that patients may be overrelying on more intact familiarity processes to support recognition accuracy. This potential compensatory strategy is particularly marked in those patients with the worst recollection abilities. The finding that recognition accuracy remains impaired in both patient subgroups, however, reveals that this compensatory familiarity-based strategy is not fully successful. Further work is needed to understand how patients can be remediated for their consistently impaired recollection processes.

Values of the phase space factors for double beta decay

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

Stoica, Sabin, E-mail: stoica@theory.nipne.ro; Mirea, Mihai; Horia Hulubei National Institute of Physics and Nuclear Engineering, 30 Reactorului street, P.O. Box MG6, Magurele

2015-10-28

We report an up-date list of the experimentally most interesting phase space factors for double beta decay (DBD). The electron/positron wave functions are obtained by solving the Dirac equations with a Coulomb potential derived from a realistic proton density distribution in nucleus and with inclusion of the finite nuclear size (FNS) and electron screening (ES) effects. We build up new numerical routines which allow us a good control of the accuracy of calculations. We found several notable differences as compared with previous results reported in literature and possible sources of these discrepancies are discussed.

Complex space monofilar approximation of diffraction currents on a conducting half plane

NASA Technical Reports Server (NTRS)

Lindell, I. V.

1987-01-01

Simple approximation of diffraction surface currents on a conducting half plane, due to an incoming plane wave, is obtained with a line current (monofile) in complex space. When compared to an approximating current at the edge, the diffraction pattern is seen to improve by an order of magnitude for a minimal increase of computation effort. Thus, the inconvient Fresnel integral functions can be avoided for quick calculations of diffracted fields and the accuracy is good in other directions than along the half plane. The method can be applied to general problems involving planar metal edges.

Performance characteristics of three-phase induction motors

NASA Technical Reports Server (NTRS)

Wood, M. E.

1977-01-01

An investigation into the characteristics of three phase, 400 Hz, induction motors of the general type used on aircraft and spacecraft is summarized. Results of laboratory tests are presented and compared with results from a computer program. Representative motors were both tested and simulated under nominal conditions as well as off nominal conditions of temperature, frequency, voltage magnitude, and voltage balance. Good correlation was achieved between simulated and laboratory results. The primary purpose of the program was to verify the simulation accuracy of the computer program, which in turn will be used as an analytical tool to support the shuttle orbiter.

A Method for Determining the Rate of Heat Transfer from a Wing or Streamline Body

NASA Technical Reports Server (NTRS)

Frick, Charles W; Mccullough, George B

1945-01-01

A method for calculating the rate of heat transfer from the surface of an airfoil or streamline body is presented. A comparison with the results of an experimental investigation indicates that the accuracy of the method is good. This method may be used to calculate the heat supply necessary for heat de-icing or in ascertaining the heat loss from the fuselage of an aircraft operating at great altitude. To illustrate the method, the total rate of heat transfer from an airfoil is calculated and compared with the experimental results.

A Weighted Measurement Fusion Particle Filter for Nonlinear Multisensory Systems Based on Gauss–Hermite Approximation

PubMed Central

Li, Yun

2017-01-01

We addressed the fusion estimation problem for nonlinear multisensory systems. Based on the Gauss–Hermite approximation and weighted least square criterion, an augmented high-dimension measurement from all sensors was compressed into a lower dimension. By combining the low-dimension measurement function with the particle filter (PF), a weighted measurement fusion PF (WMF-PF) is presented. The accuracy of WMF-PF appears good and has a lower computational cost when compared to centralized fusion PF (CF-PF). An example is given to show the effectiveness of the proposed algorithms. PMID:28956862

Validity of Eucken formula and Stokes’ viscosity relation in high-temperature electronically excited gases

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

Istomin, V. A.; Kustova, E. V.; Mekhonoshina, M. A.

2014-12-09

In the present work we evaluate the accuracy of the Eucken formula and Stokes’ viscosity relation in high temperature non-equilibrium air species with electronic excitation. The thermal conductivity coefficient calculated using the exact kinetic theory methods is compared with that obtained applying approximate formulas in the temperature range 200–20000 K. A modification of the Eucken formula providing a good agreement with exact calculations is proposed. It is shown that the Stokes viscosity relation is not valid in electronically excited monoatomic gases at temperatures higher than 2000 K.

Radiation Protection Considerations

NASA Astrophysics Data System (ADS)

Adorisio, C.; Roesler, S.; Urscheler, C.; Vincke, H.

This chapter summarizes the legal Radiation Protection (RP) framework to be considered in the design of HiLumi LHC. It details design limits and constraints, dose objectives and explains how the As Low As Reasonably Achievable (ALARA) approach is formalized at CERN. Furthermore, features of the FLUKA Monte Carlo code are summarized that are of relevance for RP studies. Results of FLUKA simulations for residual dose rates during Long Shutdown 1 (LS1) are compared to measurements demonstrating good agreement and providing proof for the accuracy of FLUKA predictions for future shutdowns. Finally, an outlook for the residual dose rate evolution until LS3 is given.

65Zn and 133Ba standardizing by photon-photon coincidence counting

NASA Astrophysics Data System (ADS)

Loureiro, Jamir S.; da Cruz, Paulo A. L.; Iwahara, Akira; Delgado, José U.; Lopes, Ricardo T.

2018-03-01

The LNMRI/Brazil has deployed a system using X-gamma coincidence technique for the standardizing radionuclide, which present simple and complex decay scheme with X-rays of energy below 100 keV. The work was carried on radionuclide metrology laboratory using a sodium iodide detector, for gamma photons, in combination with a high purity germanium detector for X-rays. Samples of 65Zn and 133Ba were standardized and the results for both radionuclides showed good precision and accuracy when compared with reference values. The standardization differences were 0.72 % for 65Zn and 0.48 % for 133Ba samples.

An anthropomorphic abdominal phantom for deformable image registration accuracy validation in adaptive radiation therapy.

PubMed

Liao, Yuliang; Wang, Linjing; Xu, Xiangdong; Chen, Haibin; Chen, Jiawei; Zhang, Guoqian; Lei, Huaiyu; Wang, Ruihao; Zhang, Shuxu; Gu, Xuejun; Zhen, Xin; Zhou, Linghong

2017-06-01

To design and construct a three-dimensional (3D) anthropomorphic abdominal phantom for geometric accuracy and dose summation accuracy evaluations of deformable image registration (DIR) algorithms for adaptive radiation therapy (ART). Organ molds, including liver, kidney, spleen, stomach, vertebra, and two metastasis tumors, were 3D printed using contours from an ovarian cancer patient. The organ molds were molded with deformable gels made of different mixtures of polyvinyl chloride (PVC) and the softener dioctyl terephthalate. Gels with different densities were obtained by a polynomial fitting curve that described the relation between the Hounsfield unit (HU) and PVC-softener blending ratio. The rigid vertebras were constructed by molding of white cement and cellulose pulp. The final abdominal phantom was assembled by arranging all the fabricated organs inside a hollow dummy according to their anatomies, and sealed by deformable gel with averaged HU of muscle and fat. Fiducial landmarks were embedded inside the phantom for spatial accuracy and dose accumulation accuracy studies. Two channels were excavated to facilitate ionization chamber insertion for dosimetric measurements. Phantom properties such as deformable gel elasticity and HU stability were studied. The dosimetric measurement accuracy in the phantom was performed, and the DIR accuracies of three DIR algorithms available in the open source DIR toolkit-DIRART were also validated. The constructed deformable gel showed elastic behavior and was stable in HU values over times, proving to be a practical material for the deformable phantom. The constructed abdominal phantom consisted of realistic anatomies in terms of both anatomical shapes and densities when compared with its reference patient. The dosimetric measurements showed a good agreement with the calculated doses from the treatment planning system. Fiducial-based accuracy analysis conducted on the constructed phantom demonstrated the feasibility of applying the phantom for organ-wise DIR accuracy assessment. We have designed and constructed an anthropomorphic abdominal deformable phantom with satisfactory elastic property, realistic organ density, and anatomy. This physical phantom can be used for routine validations of DIR geometric accuracy and dose accumulation accuracy in ART. © 2017 American Association of Physicists in Medicine.

Parallel Decomposition of the Fictitious Lagrangian Algorithm and its Accuracy for Molecular Dynamics Simulations of Semiconductors.

NASA Astrophysics Data System (ADS)

Yeh, Mei-Ling

We have performed a parallel decomposition of the fictitious Lagrangian method for molecular dynamics with tight-binding total energy expression into the hypercube computer. This is the first time in literature that the dynamical simulation of semiconducting systems containing more than 512 silicon atoms has become possible with the electrons treated as quantum particles. With the utilization of the Intel Paragon system, our timing analysis predicts that our code is expected to perform realistic simulations on very large systems consisting of thousands of atoms with time requirements of the order of tens of hours. Timing results and performance analysis of our parallel code are presented in terms of calculation time, communication time, and setup time. The accuracy of the fictitious Lagrangian method in molecular dynamics simulation is also investigated, especially the energy conservation of the total energy of ions. We find that the accuracy of the fictitious Lagrangian scheme in small silicon cluster and very large silicon system simulations is good for as long as the simulations proceed, even though we quench the electronic coordinates to the Born-Oppenheimer surface only in the beginning of the run. The kinetic energy of electrons does not increase as time goes on, and the energy conservation of the ionic subsystem remains very good. This means that, as far as the ionic subsystem is concerned, the electrons are on the average in the true quantum ground states. We also tie up some odds and ends regarding a few remaining questions about the fictitious Lagrangian method, such as the difference between the results obtained from the Gram-Schmidt and SHAKE method of orthonormalization, and differences between simulations where the electrons are quenched to the Born -Oppenheimer surface only once compared with periodic quenching.

Survival prediction of trauma patients: a study on US National Trauma Data Bank.

PubMed

Sefrioui, I; Amadini, R; Mauro, J; El Fallahi, A; Gabbrielli, M

2017-12-01

Exceptional circumstances like major incidents or natural disasters may cause a huge number of victims that might not be immediately and simultaneously saved. In these cases it is important to define priorities avoiding to waste time and resources for not savable victims. Trauma and Injury Severity Score (TRISS) methodology is the well-known and standard system usually used by practitioners to predict the survival probability of trauma patients. However, practitioners have noted that the accuracy of TRISS predictions is unacceptable especially for severely injured patients. Thus, alternative methods should be proposed. In this work we evaluate different approaches for predicting whether a patient will survive or not according to simple and easily measurable observations. We conducted a rigorous, comparative study based on the most important prediction techniques using real clinical data of the US National Trauma Data Bank. Empirical results show that well-known Machine Learning classifiers can outperform the TRISS methodology. Based on our findings, we can say that the best approach we evaluated is Random Forest: it has the best accuracy, the best area under the curve, and k-statistic, as well as the second-best sensitivity and specificity. It has also a good calibration curve. Furthermore, its performance monotonically increases as the dataset size grows, meaning that it can be very effective to exploit incoming knowledge. Considering the whole dataset, it is always better than TRISS. Finally, we implemented a new tool to compute the survival of victims. This will help medical practitioners to obtain a better accuracy than the TRISS tools. Random Forests may be a good candidate solution for improving the predictions on survival upon the standard TRISS methodology.

Stress echocardiography with smartphone: real-time remote reading for regional wall motion.

PubMed

Scali, Maria Chiara; de Azevedo Bellagamba, Clarissa Carmona; Ciampi, Quirino; Simova, Iana; de Castro E Silva Pretto, José Luis; Djordjevic-Dikic, Ana; Dodi, Claudio; Cortigiani, Lauro; Zagatina, Angela; Trambaiolo, Paolo; Torres, Marco R; Citro, Rodolfo; Colonna, Paolo; Paterni, Marco; Picano, Eugenio

2017-11-01

The diffusion of smart-phones offers access to the best remote expertise in stress echo (SE). To evaluate the reliability of SE based on smart-phone filming and reading. A set of 20 SE video-clips were read in random sequence with a multiple choice six-answer test by ten readers from five different countries (Italy, Brazil, Serbia, Bulgaria, Russia) of the "SE2020" study network. The gold standard to assess accuracy was a core-lab expert reader in agreement with angiographic verification (0 = wrong, 1 = right). The same set of 20 SE studies were read, in random order and >2 months apart, on desktop Workstation and via smartphones by ten remote readers. Image quality was graded from 1 = poor but readable, to 3 = excellent. Kappa (k) statistics was used to assess intra- and inter-observer agreement. The image quality was comparable in desktop workstation vs. smartphone (2.0 ± 0.5 vs. 2.4 ± 0.7, p = NS). The average reading time per case was similar for desktop versus smartphone (90 ± 39 vs. 82 ± 54 s, p = NS). The overall diagnostic accuracy of the ten readers was similar for desktop workstation vs. smartphone (84 vs. 91%, p = NS). Intra-observer agreement (desktop vs. smartphone) was good (k = 0.81 ± 0.14). Inter-observer agreement was good and similar via desktop or smartphone (k = 0.69 vs. k = 0.72, p = NS). The diagnostic accuracy and consistency of SE reading among certified readers was high and similar via desktop workstation or via smartphone.

Evaluation of CROES Nephrolithometry Nomogram as a Preoperative Predictive System for Percutaneous Nephrolithotomy Outcomes.

PubMed

Kumar, Sumit; Sreenivas, Jayaram; Karthikeyan, Vilvapathy Senguttuvan; Mallya, Ashwin; Keshavamurthy, Ramaiah

2016-10-01

Scoring systems have been devised to predict outcomes of percutaneous nephrolithotomy (PCNL). CROES nephrolithometry nomogram (CNN) is the latest tool devised to predict stone-free rate (SFR). We aim to compare predictive accuracy of CNN against Guy stone score (GSS) for SFR and postoperative outcomes. Between January 2013 and December 2015, 313 patients undergoing PCNL were analyzed for predictive accuracy of GSS, CNN, and stone burden (SB) for SFR, complications, operation time (OT), and length of hospitalization (LOH). We further stratified patients into risk groups based on CNN and GSS. Mean ± standard deviation (SD) SB was 298.8 ± 235.75 mm 2 . SB, GSS, and CNN (area under curve [AUC]: 0.662, 0.660, 0.673) were found to be predictors of SFR. However, predictability for complications was not as good (AUC: SB 0.583, GSS 0.554, CNN 0.580). Single implicated calix (Adj. OR 3.644; p = 0.027), absence of staghorn calculus (Adj. OR 3.091; p = 0.044), single stone (Adj. OR 3.855; p = 0.002), and single puncture (Adj. OR 2.309; p = 0.048) significantly predicted SFR on multivariate analysis. Charlson comorbidity index (CCI; p = 0.020) and staghorn calculus (p = 0.002) were independent predictors for complications on linear regression. SB and GSS independently predicted OT on multivariate analysis. SB and complications significantly predicted LOH, while GSS and CNN did not predict LOH. CNN offered better risk stratification for residual stones than GSS. CNN and GSS have good preoperative predictive accuracy for SFR. Number of implicated calices may affect SFR, and CCI affects complications. Studies should incorporate these factors in scoring systems and assess if predictability of PCNL outcomes improves.

MRL and SuperFine+MRL: new supertree methods

PubMed Central

2012-01-01

Background Supertree methods combine trees on subsets of the full taxon set together to produce a tree on the entire set of taxa. Of the many supertree methods, the most popular is MRP (Matrix Representation with Parsimony), a method that operates by first encoding the input set of source trees by a large matrix (the "MRP matrix") over {0,1, ?}, and then running maximum parsimony heuristics on the MRP matrix. Experimental studies evaluating MRP in comparison to other supertree methods have established that for large datasets, MRP generally produces trees of equal or greater accuracy than other methods, and can run on larger datasets. A recent development in supertree methods is SuperFine+MRP, a method that combines MRP with a divide-and-conquer approach, and produces more accurate trees in less time than MRP. In this paper we consider a new approach for supertree estimation, called MRL (Matrix Representation with Likelihood). MRL begins with the same MRP matrix, but then analyzes the MRP matrix using heuristics (such as RAxML) for 2-state Maximum Likelihood. Results We compared MRP and SuperFine+MRP with MRL and SuperFine+MRL on simulated and biological datasets. We examined the MRP and MRL scores of each method on a wide range of datasets, as well as the resulting topological accuracy of the trees. Our experimental results show that MRL, coupled with a very good ML heuristic such as RAxML, produced more accurate trees than MRP, and MRL scores were more strongly correlated with topological accuracy than MRP scores. Conclusions SuperFine+MRP, when based upon a good MP heuristic, such as TNT, produces among the best scores for both MRP and MRL, and is generally faster and more topologically accurate than other supertree methods we tested. PMID:22280525

SU-E-T-396: Dosimetric Accuracy of Proton Therapy for Patients with Metal Implants in CT Scans Using Metal Deletion Technique (MDT) Artifacts Reduction

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

Li, X; Kantor, M; Zhu, X

2014-06-01

Purpose: To evaluate the dosimetric accuracy for proton therapy patients with metal implants in CT using metal deletion technique (MDT) artifacts reduction. Methods: Proton dose accuracies under CT metal artifacts were first evaluated using a water phantom with cylindrical inserts of different materials (titanium and steel). Ranges and dose profiles along different beam angles were calculated using treatment planning system (Eclipse version 8.9) on uncorrected CT, MDT CT, and manually-corrected CT, where true Hounsfield units (water) were assigned to the streak artifacts. In patient studies, the treatment plans were developed on manually-corrected CTs, then recalculated on MDT and uncorrected CTs.more » DVH indices were compared between the dose distributions on all the CTs. Results: For water phantom study with 1/2 inch titanium insert, the proton range differences estimated by MDT CT were with 1% for all beam angles, while the range error can be up to 2.6% for uncorrected CT. For the study with 1 inch stainless steel insert, the maximum range error calculated by MDT CT was 1.09% among all the beam angles compared with maximum range error with 4.7% for uncorrected CT. The dose profiles calculated on MDT CTs for both titanium and steel inserts showed very good agreements with the ones calculated on manually-corrected CTs, while large dose discrepancies calculated using uncorrected CTs were observed in the distal end region of the proton beam. The patient study showed similar dose distribution and DVHs for organs near the metal artifacts recalculated on MDT CT compared with the ones calculated on manually-corrected CT, while the differences between uncorrected and corrected CTs were much pronounced. Conclusion: In proton therapy, large dose error could occur due to metal artifact. The MDT CT can be used for proton dose calculation to achieve similar dose accuracy as the current clinical practice using manual correction.« less

Efficacy of Transcerebellar Diameter/Abdominal Circumference Versus Head Circumference/Abdominal Circumference in Predicting Asymmetric Intrauterine Growth Retardation

PubMed Central

Bhimarao; Bhat, Venkataramana; Gowda, Puttanna VN

2015-01-01

Background The high incidence of IUGR and its low recognition lead to increasing perinatal morbidity and mortality for which prediction of IUGR with timely management decisions is of paramount importance. Many studies have compared the efficacy of several gestational age independent parameters and found that TCD/AC is a better predictor of asymmetric IUGR. Aim To compare the accuracy of transcerebellar diameter/abdominal circumference with head circumference/abdominal circumference in predicting asymmetric intrauterine growth retardation after 20 weeks of gestation. Materials and Methods The prospective study was conducted over a period of one year on 50 clinically suspected IUGR pregnancies who were evaluated with 3.5 MHz frequency ultrasound scanner by a single sonologist. BPD, HC, AC and FL along with TCD were measured for assessing the sonological gestational age. Two morphometric ratios- TCD/AC and HC/AC were calculated. Estimated fetal weight was calculated for all these pregnancies and its percentile was determined. Statistical Methods The TCD/AC and HC/AC ratios were correlated with advancing gestational age to know if these were related to GA. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy (DA) for TCD/AC and HC/AC ratios in evaluating IUGR fetuses were calculated. Results In the present study, linear relation of TCD and HC in IUGR fetuses with gestation was noted. The sensitivity, specificity, PPV, NPV & DA were 88%, 93.5%, 77.1%, 96.3% & 92.4% respectively for TCD/AC ratio versus 84%, 92%, 72.4%, 95.8% & 90.4% respectively for HC/AC ratio in predicting IUGR. Conclusion Both ratios were gestational age independent and can be used in detecting IUGR with good diagnostic accuracy. However, TCD/AC ratio had a better diagnostic validity and accuracy compared to HC/AC ratio in predicting asymmetric IUGR. PMID:26557588

Diagnostic accuracy of level 3 portable sleep tests versus level 1 polysomnography for sleep-disordered breathing: a systematic review and meta-analysis

PubMed Central

El Shayeb, Mohamed; Topfer, Leigh-Ann; Stafinski, Tania; Pawluk, Lawrence; Menon, Devidas

2014-01-01

Background: Greater awareness of sleep-disordered breathing and rising obesity rates have fueled demand for sleep studies. Sleep testing using level 3 portable devices may expedite diagnosis and reduce the costs associated with level 1 in-laboratory polysomnography. We sought to assess the diagnostic accuracy of level 3 testing compared with level 1 testing and to identify the appropriate patient population for each test. Methods: We conducted a systematic review and meta-analysis of comparative studies of level 3 versus level 1 sleep tests in adults with suspected sleep-disordered breathing. We searched 3 research databases and grey literature sources for studies that reported on diagnostic accuracy parameters or disease management after diagnosis. Two reviewers screened the search results, selected potentially relevant studies and extracted data. We used a bivariate mixed-effects binary regression model to estimate summary diagnostic accuracy parameters. Results: We included 59 studies involving a total of 5026 evaluable patients (mostly patients suspected of having obstructive sleep apnea). Of these, 19 studies were included in the meta-analysis. The estimated area under the receiver operating characteristics curve was high, ranging between 0.85 and 0.99 across different levels of disease severity. Summary sensitivity ranged between 0.79 and 0.97, and summary specificity ranged between 0.60 and 0.93 across different apnea–hypopnea cut-offs. We saw no significant difference in the clinical management parameters between patients who underwent either test to receive their diagnosis. Interpretation: Level 3 portable devices showed good diagnostic performance compared with level 1 sleep tests in adult patients with a high pretest probability of moderate to severe obstructive sleep apnea and no unstable comorbidities. For patients suspected of having other types of sleep-disordered breathing or sleep disorders not related to breathing, level 1 testing remains the reference standard. PMID:24218531

A New Method to Cross Calibrate and Validate TOMS, SBUV/2, and SCIAMACHY Measurements

NASA Technical Reports Server (NTRS)

Ahmad, Ziauddin; Hilsenrath, Ernest; Einaudi, Franco (Technical Monitor)

2001-01-01

A unique method to validate back scattered ultraviolet (buv) type satellite data that complements the measurements from existing ground networks is proposed. The method involves comparing the zenith sky radiance measurements from the ground to the nadir radiance measurements taken from space. Since the measurements are compared directly, the proposed method is superior to any other method that involves comparing derived products (for example, ozone), because comparison of derived products involve inversion algorithms which are susceptible to several type of errors. Forward radiative transfer (RT) calculations show that for an aerosol free atmosphere, the ground-based zenith sky radiance measurement and the satellite nadir radiance measurements can be predicted with an accuracy of better than 1 percent. The RT computations also show that for certain values of the solar zenith angles, the radiance comparisons could be better than half a percent. This accuracy is practically independent of ozone amount and aerosols in the atmosphere. Experiences with the Shuttle Solar Backscatter Ultraviolet (SSBUV) program show that the accuracy of the ground-based zenith sky radiance measuring instrument can be maintained at a level of a few tenth of a percent. This implies that the zenith sky radiance measurements can be used to validate Total Ozone Mapping Spectrometer (TOMS), Solar Backscatter Ultraviolet (SBUV/2), and The SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) radiance data. Also, this method will help improve the long term precision of the measurements for better trend detection and the accuracy of other BUV products such as tropospheric ozone and aerosols. Finally, in the long term, this method is a good candidate to inter-calibrate and validate long term observations of upcoming operational instruments such as Global Ozone Monitoring Experiment (GOME-2), Ozone Mapping Instrument (OMI), Ozone Dynamics Ultraviolet Spectrometer (ODUS), and Ozone Mapping and Profiler Suite (OMPS).

Validation of Photoplethysmography-Based Sleep Staging Compared With Polysomnography in Healthy Middle-Aged Adults.

PubMed

Fonseca, Pedro; Weysen, Tim; Goelema, Maaike S; Møst, Els I S; Radha, Mustafa; Lunsingh Scheurleer, Charlotte; van den Heuvel, Leonie; Aarts, Ronald M

2017-07-01

To compare the accuracy of automatic sleep staging based on heart rate variability measured from photoplethysmography (PPG) combined with body movements measured with an accelerometer, with polysomnography (PSG) and actigraphy. Using wrist-worn PPG to analyze heart rate variability and an accelerometer to measure body movements, sleep stages and sleep statistics were automatically computed from overnight recordings. Sleep-wake, 4-class (wake/N1 + N2/N3/REM) and 3-class (wake/NREM/REM) classifiers were trained on 135 simultaneously recorded PSG and PPG recordings of 101 healthy participants and validated on 80 recordings of 51 healthy middle-aged adults. Epoch-by-epoch agreement and sleep statistics were compared with actigraphy for a subset of the validation set. The sleep-wake classifier obtained an epoch-by-epoch Cohen's κ between PPG and PSG sleep stages of 0.55 ± 0.14, sensitivity to wake of 58.2 ± 17.3%, and accuracy of 91.5 ± 5.1%. κ and sensitivity were significantly higher than with actigraphy (0.40 ± 0.15 and 45.5 ± 19.3%, respectively). The 3-class classifier achieved a κ of 0.46 ± 0.15 and accuracy of 72.9 ± 8.3%, and the 4-class classifier, a κ of 0.42 ± 0.12 and accuracy of 59.3 ± 8.5%. The moderate epoch-by-epoch agreement and, in particular, the good agreement in terms of sleep statistics suggest that this technique is promising for long-term sleep monitoring, although more evidence is needed to understand whether it can complement PSG in clinical practice. It also offers an improvement in sleep/wake detection over actigraphy for healthy individuals, although this must be confirmed on a larger, clinical population. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Parasitic Parameters Extraction for InP DHBT Based on EM Method and Validation up to H-Band

NASA Astrophysics Data System (ADS)

Li, Oupeng; Zhang, Yong; Wang, Lei; Xu, Ruimin; Cheng, Wei; Wang, Yuan; Lu, Haiyan

2017-05-01

This paper presents a small-signal model for InGaAs/InP double heterojunction bipolar transistor (DHBT). Parasitic parameters of access via and electrode finger are extracted by 3-D electromagnetic (EM) simulation. By analyzing the equivalent circuit of seven special structures and using the EM simulation results, the parasitic parameters are extracted systematically. Compared with multi-port s-parameter EM model, the equivalent circuit model has clear physical intension and avoids the complex internal ports setting. The model is validated on a 0.5 × 7 μm2 InP DHBT up to 325 GHz. The model provides a good fitting result between measured and simulated multi-bias s-parameters in full band. At last, an H-band amplifier is designed and fabricated for further verification. The measured amplifier performance is highly agreed with the model prediction, which indicates the model has good accuracy in submillimeterwave band.

Musical aptitude and second language pronunciation skills in school-aged children: neural and behavioral evidence.

PubMed

Milovanov, Riia; Huotilainen, Minna; Välimäki, Vesa; Esquef, Paulo A A; Tervaniemi, Mari

2008-02-15

The main focus of this study was to examine the relationship between musical aptitude and second language pronunciation skills. We investigated whether children with superior performance in foreign language production represent musical sound features more readily in the preattentive level of neural processing compared with children with less-advanced production skills. Sound processing accuracy was examined in elementary school children by means of event-related potential (ERP) recordings and behavioral measures. Children with good linguistic skills had better musical skills as measured by the Seashore musicality test than children with less accurate linguistic skills. The ERP data accompany the results of the behavioral tests: children with good linguistic skills showed more pronounced sound-change evoked activation with the music stimuli than children with less accurate linguistic skills. Taken together, the results imply that musical and linguistic skills could partly be based on shared neural mechanisms.

A fast determination method for transverse relaxation of spin-exchange-relaxation-free magnetometer

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

Lu, Jixi, E-mail: lujixi@buaa.edu.cn; Qian, Zheng; Fang, Jiancheng

2015-04-15

We propose a fast and accurate determination method for transverse relaxation of the spin-exchange-relaxation-free (SERF) magnetometer. This method is based on the measurement of magnetic resonance linewidth via a chirped magnetic field excitation and the amplitude spectrum analysis. Compared with the frequency sweeping via separate sinusoidal excitation, our method can realize linewidth determination within only few seconds and meanwhile obtain good frequency resolution. Therefore, it can avoid the drift error in long term measurement and improve the accuracy of the determination. As the magnetic resonance frequency of the SERF magnetometer is very low, we include the effect of the negativemore » resonance frequency caused by the chirp and achieve the coefficient of determination of the fitting results better than 0.998 with 95% confidence bounds to the theoretical equation. The experimental results are in good agreement with our theoretical analysis.« less

Critically re-evaluating a common technique: Accuracy, reliability, and confirmation bias of EMG.

PubMed

Narayanaswami, Pushpa; Geisbush, Thomas; Jones, Lyell; Weiss, Michael; Mozaffar, Tahseen; Gronseth, Gary; Rutkove, Seward B

2016-01-19

(1) To assess the diagnostic accuracy of EMG in radiculopathy. (2) To evaluate the intrarater reliability and interrater reliability of EMG in radiculopathy. (3) To assess the presence of confirmation bias in EMG. Three experienced academic electromyographers interpreted 3 compact discs with 20 EMG videos (10 normal, 10 radiculopathy) in a blinded, standardized fashion without information regarding the nature of the study. The EMGs were interpreted 3 times (discs A, B, C) 1 month apart. Clinical information was provided only with disc C. Intrarater reliability was calculated by comparing interpretations in discs A and B, interrater reliability by comparing interpretation between reviewers. Confirmation bias was estimated by the difference in correct interpretations when clinical information was provided. Sensitivity was similar to previous reports (77%, confidence interval [CI] 63%-90%); specificity was 71%, CI 56%-85%. Intrarater reliability was good (κ 0.61, 95% CI 0.41-0.81); interrater reliability was lower (κ 0.53, CI 0.35-0.71). There was no substantial confirmation bias when clinical information was provided (absolute difference in correct responses 2.2%, CI -13.3% to 17.7%); the study lacked precision to exclude moderate confirmation bias. This study supports that (1) serial EMG studies should be performed by the same electromyographer since intrarater reliability is better than interrater reliability; (2) knowledge of clinical information does not bias EMG interpretation substantially; (3) EMG has moderate diagnostic accuracy for radiculopathy with modest specificity and electromyographers should exercise caution interpreting mild abnormalities. This study provides Class III evidence that EMG has moderate diagnostic accuracy and specificity for radiculopathy. © 2015 American Academy of Neurology.

Comparison of several von Willebrand factor (VWF) activity assays for monitoring patients undergoing treatment with VWF/FVIII concentrates: improved performance with a new modified automated method.

PubMed

Hillarp, A; Friedman, K D; Adcock-Funk, D; Tiefenbacher, S; Nichols, W L; Chen, D; Stadler, M; Schwartz, B A

2015-11-01

The ability of von Willebrand factor (VWF) to bind platelet GP Ib and promote platelet plug formation is measured in vitro using the ristocetin cofactor (VWF:RCo) assay. Automated assay systems make testing more accessible for diagnosis, but do not necessarily improve sensitivity and accuracy. We assessed the performance of a modified automated VWF:RCo assay protocol for the Behring Coagulation System (BCS(®) ) compared to other available assay methods. Results from different VWF:RCo assays in a number of specialized commercial and research testing laboratories were compared using plasma samples with varying VWF:RCo activities (0-1.2 IU mL(-1) ). Samples were prepared by mixing VWF concentrate or plasma standard into VWF-depleted plasma. Commercially available lyophilized standard human plasma was also studied. Emphasis was put on the low measuring range. VWF:RCo accuracy was calculated based on the expected values, whereas precision was obtained from repeated measurements. In the physiological concentration range, most of the automated tests resulted in acceptable accuracy, with varying reproducibility dependent on the method. However, several assays were inaccurate in the low measuring range. Only the modified BCS protocol showed acceptable accuracy over the entire measuring range with improved reproducibility. A modified BCS(®) VWF:RCo method can improve sensitivity and thus enhances the measuring range. Furthermore, the modified BCS(®) assay displayed good precision. This study indicates that the specific modifications - namely the combination of increased ristocetin concentration, reduced platelet content, VWF-depleted plasma as on-board diluent and a two-curve calculation mode - reduces the issues seen with current VWF:RCo activity assays. © 2015 John Wiley & Sons Ltd.

Artificial neural networks: Predicting head CT findings in elderly patients presenting with minor head injury after a fall.

PubMed

Dusenberry, Michael W; Brown, Charles K; Brewer, Kori L

2017-02-01

To construct an artificial neural network (ANN) model that can predict the presence of acute CT findings with both high sensitivity and high specificity when applied to the population of patients≥age 65years who have incurred minor head injury after a fall. An ANN was created in the Python programming language using a population of 514 patients ≥ age 65 years presenting to the ED with minor head injury after a fall. The patient dataset was divided into three parts: 60% for "training", 20% for "cross validation", and 20% for "testing". Sensitivity, specificity, positive and negative predictive values, and accuracy were determined by comparing the model's predictions to the actual correct answers for each patient. On the "cross validation" data, the model attained a sensitivity ("recall") of 100.00%, specificity of 78.95%, PPV ("precision") of 78.95%, NPV of 100.00%, and accuracy of 88.24% in detecting the presence of positive head CTs. On the "test" data, the model attained a sensitivity of 97.78%, specificity of 89.47%, PPV of 88.00%, NPV of 98.08%, and accuracy of 93.14% in detecting the presence of positive head CTs. ANNs show great potential for predicting CT findings in the population of patients ≥ 65 years of age presenting with minor head injury after a fall. As a good first step, the ANN showed comparable sensitivity, predictive values, and accuracy, with a much higher specificity than the existing decision rules in clinical usage for predicting head CTs with acute intracranial findings. Copyright © 2016 Elsevier Inc. All rights reserved.

A Comparative Study on Diagnostic Accuracy of Colour Coded Digital Images, Direct Digital Images and Conventional Radiographs for Periapical Lesions – An In Vitro Study

PubMed Central

Mubeen; K.R., Vijayalakshmi; Bhuyan, Sanat Kumar; Panigrahi, Rajat G; Priyadarshini, Smita R; Misra, Satyaranjan; Singh, Chandravir

2014-01-01

Objectives: The identification and radiographic interpretation of periapical bone lesions is important for accurate diagnosis and treatment. The present study was undertaken to study the feasibility and diagnostic accuracy of colour coded digital radiographs in terms of presence and size of lesion and to compare the diagnostic accuracy of colour coded digital images with direct digital images and conventional radiographs for assessing periapical lesions. Materials and Methods: Sixty human dry cadaver hemimandibles were obtained and periapical lesions were created in first and second premolar teeth at the junction of cancellous and cortical bone using a micromotor handpiece and carbide burs of sizes 2, 4 and 6. After each successive use of round burs, a conventional, RVG and colour coded image was taken for each specimen. All the images were evaluated by three observers. The diagnostic accuracy for each bur and image mode was calculated statistically. Results: Our results showed good interobserver (kappa > 0.61) agreement for the different radiographic techniques and for the different bur sizes. Conventional Radiography outperformed Digital Radiography in diagnosing periapical lesions made with Size two bur. Both were equally diagnostic for lesions made with larger bur sizes. Colour coding method was least accurate among all the techniques. Conclusion: Conventional radiography traditionally forms the backbone in the diagnosis, treatment planning and follow-up of periapical lesions. Direct digital imaging is an efficient technique, in diagnostic sense. Colour coding of digital radiography was feasible but less accurate however, this imaging technique, like any other, needs to be studied continuously with the emphasis on safety of patients and diagnostic quality of images. PMID:25584318

Direct comparison of PI-RADS version 2 and version 1 regarding interreader agreement and diagnostic accuracy for the detection of clinically significant prostate cancer.

PubMed

Becker, Anton S; Cornelius, Alexander; Reiner, Cäcilia S; Stocker, Daniel; Ulbrich, Erika J; Barth, Borna K; Mortezavi, Ashkan; Eberli, Daniel; Donati, Olivio F

2017-09-01

to simultaneously evaluate interreader agreement and diagnostic accuracy in the of PI-RADS v2 and compare it to v1. A total of 67 patients (median age 65.3 y, range 51.2-78.2 y; PSA 6.8μg/L, 0.2-33μg/L) undergoing MRI of the prostate and subsequent transperineal template biopsy within ≤6 months from MRI were included. Four readers from two institutions evaluated the likelihood of prostate cancer using PI-RADS v1 and v2 in two separate reading sessions ≥3 months apart. Interreader agreement was assessed for each pulse-sequence and for total PI-RADS scores using the intraclass correlation coefficient (ICC). Differences were considered significant for non-overlapping 95%-confidence intervals. Diagnostic accuracy was assessed with the area under the receiver operating characteristic curve (A Z ). A p-value <0.05 was considered statistically significant. Interreader agreement for DCE-scores was good in v2 (ICC 2 =0.70; 95% CI: 0.66-0.74) and slightly lower in v1 (ICC 1 =0.64, 0.59-0.69). Agreement for DWI scores (ICC 1 =0.77, ICC 2 =0.76) as well as final PI-RADS scores per quadrant were nearly identical (ICC 1 =ICC 2 =0.71). Diagnostic accuracy showed no significant differences (p=0.09-0.93) between v1 and v2 in any of the readers (range: A Z =0.78-0.88). PI-RADS scores show similar interreader agreement in v2 and v1 at comparable diagnostic performance. The simplification of the DCE interpretation in v2 might slightly improve agreement while not negatively affecting diagnostic performance. Copyright © 2017 Elsevier B.V. All rights reserved.

Geometric and mechanical evaluation of 3D-printing materials for skull base anatomical education and endoscopic surgery simulation - A first step to create reliable customized simulators.

PubMed

Favier, Valentin; Zemiti, Nabil; Caravaca Mora, Oscar; Subsol, Gérard; Captier, Guillaume; Lebrun, Renaud; Crampette, Louis; Mondain, Michel; Gilles, Benjamin

2017-01-01

Endoscopic skull base surgery allows minimal invasive therapy through the nostrils to treat infectious or tumorous diseases. Surgical and anatomical education in this field is limited by the lack of validated training models in terms of geometric and mechanical accuracy. We choose to evaluate several consumer-grade materials to create a patient-specific 3D-printed skull base model for anatomical learning and surgical training. Four 3D-printed consumer-grade materials were compared to human cadaver bone: calcium sulfate hemihydrate (named Multicolor), polyamide, resin and polycarbonate. We compared the geometric accuracy, forces required to break thin walls of materials and forces required during drilling. All materials had an acceptable global geometric accuracy (from 0.083mm to 0.203mm of global error). Local accuracy was better in polycarbonate (0.09mm) and polyamide (0.15mm) than in Multicolor (0.90mm) and resin (0.86mm). Resin and polyamide thin walls were not broken at 200N. Forces needed to break Multicolor thin walls were 1.6-3.5 times higher than in bone. For polycarbonate, forces applied were 1.6-2.5 times higher. Polycarbonate had a mode of fracture similar to the cadaver bone. Forces applied on materials during drilling followed a normal distribution except for the polyamide which was melted. Energy spent during drilling was respectively 1.6 and 2.6 times higher on bone than on PC and Multicolor. Polycarbonate is a good substitute of human cadaver bone for skull base surgery simulation. Thanks to short lead times and reasonable production costs, patient-specific 3D printed models can be used in clinical practice for pre-operative training, improving patient safety.

Diagnostic accuracy of an identification tool for localized neuropathic pain based on the IASP criteria.

PubMed

Mayoral, Víctor; Pérez-Hernández, Concepción; Muro, Inmaculada; Leal, Ana; Villoria, Jesús; Esquivias, Ana

2018-04-27

Based on the clear neuroanatomical delineation of many neuropathic pain (NP) symptoms, a simple tool for performing a short structured clinical encounter based on the IASP diagnostic criteria was developed to identify NP. This study evaluated its accuracy and usefulness. A case-control study was performed in 19 pain clinics within Spain. A pain clinician used the experimental screening tool (the index test, IT) to assign the descriptions of non-neuropathic (nNP), non-localized neuropathic (nLNP), and localized neuropathic (LNP) to the patients' pain conditions. The reference standard was a formal clinical diagnosis provided by another pain clinician. The accuracy of the IT was compared with that of the Douleur Neuropathique en 4 questions (DN4) and the Leeds Assessment of Neuropathic Signs and Symptoms (LANSS). Six-hundred and sixty-six patients were analyzed. There was a good agreement between the IT and the reference standard (kappa =0.722). The IT was accurate in distinguishing between LNP and nLNP (83.2% sensitivity, 88.2% specificity), between LNP and the other pain categories (nLNP + nNP) (80.0% sensitivity, 90.7% specificity), and between NP and nNP (95.5% sensitivity, 89.1% specificity). The accuracy in distinguishing between NP and nNP was comparable with that of the DN4 and the LANSS. The IT took a median of 10 min to complete. A novel instrument based on an operationalization of the IASP criteria can not only discern between LNP and nLNP, but also provide a high level of diagnostic certainty about the presence of NP after a short clinical encounter.

Adaptive estimation of state of charge and capacity with online identified battery model for vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Wei, Zhongbao; Tseng, King Jet; Wai, Nyunt; Lim, Tuti Mariana; Skyllas-Kazacos, Maria

2016-11-01

Reliable state estimate depends largely on an accurate battery model. However, the parameters of battery model are time varying with operating condition variation and battery aging. The existing co-estimation methods address the model uncertainty by integrating the online model identification with state estimate and have shown improved accuracy. However, the cross interference may arise from the integrated framework to compromise numerical stability and accuracy. Thus this paper proposes the decoupling of model identification and state estimate to eliminate the possibility of cross interference. The model parameters are online adapted with the recursive least squares (RLS) method, based on which a novel joint estimator based on extended Kalman Filter (EKF) is formulated to estimate the state of charge (SOC) and capacity concurrently. The proposed joint estimator effectively compresses the filter order which leads to substantial improvement in the computational efficiency and numerical stability. Lab scale experiment on vanadium redox flow battery shows that the proposed method is highly authentic with good robustness to varying operating conditions and battery aging. The proposed method is further compared with some existing methods and shown to be superior in terms of accuracy, convergence speed, and computational cost.

A Blade Tip Timing Method Based on a Microwave Sensor

PubMed Central

Zhang, Jilong; Duan, Fajie; Niu, Guangyue; Jiang, Jiajia; Li, Jie

2017-01-01

Blade tip timing is an effective method for blade vibration measurements in turbomachinery. This method is increasing in popularity because it is non-intrusive and has several advantages over the conventional strain gauge method. Different kinds of sensors have been developed for blade tip timing, including optical, eddy current and capacitance sensors. However, these sensors are unsuitable in environments with contaminants or high temperatures. Microwave sensors offer a promising potential solution to overcome these limitations. In this article, a microwave sensor-based blade tip timing measurement system is proposed. A patch antenna probe is used to transmit and receive the microwave signals. The signal model and process method is analyzed. Zero intermediate frequency structure is employed to maintain timing accuracy and dynamic performance, and the received signal can also be used to measure tip clearance. The timing method uses the rising and falling edges of the signal and an auto-gain control circuit to reduce the effect of tip clearance change. To validate the accuracy of the system, it is compared experimentally with a fiber optic tip timing system. The results show that the microwave tip timing system achieves good accuracy. PMID:28492469

A Blade Tip Timing Method Based on a Microwave Sensor.

PubMed

Zhang, Jilong; Duan, Fajie; Niu, Guangyue; Jiang, Jiajia; Li, Jie

2017-05-11

Blade tip timing is an effective method for blade vibration measurements in turbomachinery. This method is increasing in popularity because it is non-intrusive and has several advantages over the conventional strain gauge method. Different kinds of sensors have been developed for blade tip timing, including optical, eddy current and capacitance sensors. However, these sensors are unsuitable in environments with contaminants or high temperatures. Microwave sensors offer a promising potential solution to overcome these limitations. In this article, a microwave sensor-based blade tip timing measurement system is proposed. A patch antenna probe is used to transmit and receive the microwave signals. The signal model and process method is analyzed. Zero intermediate frequency structure is employed to maintain timing accuracy and dynamic performance, and the received signal can also be used to measure tip clearance. The timing method uses the rising and falling edges of the signal and an auto-gain control circuit to reduce the effect of tip clearance change. To validate the accuracy of the system, it is compared experimentally with a fiber optic tip timing system. The results show that the microwave tip timing system achieves good accuracy.

Research on Optimal Observation Scale for Damaged Buildings after Earthquake Based on Optimal Feature Space

NASA Astrophysics Data System (ADS)

Chen, J.; Chen, W.; Dou, A.; Li, W.; Sun, Y.

2018-04-01

A new information extraction method of damaged buildings rooted in optimal feature space is put forward on the basis of the traditional object-oriented method. In this new method, ESP (estimate of scale parameter) tool is used to optimize the segmentation of image. Then the distance matrix and minimum separation distance of all kinds of surface features are calculated through sample selection to find the optimal feature space, which is finally applied to extract the image of damaged buildings after earthquake. The overall extraction accuracy reaches 83.1 %, the kappa coefficient 0.813. The new information extraction method greatly improves the extraction accuracy and efficiency, compared with the traditional object-oriented method, and owns a good promotional value in the information extraction of damaged buildings. In addition, the new method can be used for the information extraction of different-resolution images of damaged buildings after earthquake, then to seek the optimal observation scale of damaged buildings through accuracy evaluation. It is supposed that the optimal observation scale of damaged buildings is between 1 m and 1.2 m, which provides a reference for future information extraction of damaged buildings.

Comparing SVM and ANN based Machine Learning Methods for Species Identification of Food Contaminating Beetles.

PubMed

Bisgin, Halil; Bera, Tanmay; Ding, Hongjian; Semey, Howard G; Wu, Leihong; Liu, Zhichao; Barnes, Amy E; Langley, Darryl A; Pava-Ripoll, Monica; Vyas, Himansu J; Tong, Weida; Xu, Joshua

2018-04-25

Insect pests, such as pantry beetles, are often associated with food contaminations and public health risks. Machine learning has the potential to provide a more accurate and efficient solution in detecting their presence in food products, which is currently done manually. In our previous research, we demonstrated such feasibility where Artificial Neural Network (ANN) based pattern recognition techniques could be implemented for species identification in the context of food safety. In this study, we present a Support Vector Machine (SVM) model which improved the average accuracy up to 85%. Contrary to this, the ANN method yielded ~80% accuracy after extensive parameter optimization. Both methods showed excellent genus level identification, but SVM showed slightly better accuracy  for most species. Highly accurate species level identification remains a challenge, especially in distinguishing between species from the same genus which may require improvements in both imaging and machine learning techniques. In summary, our work does illustrate a new SVM based technique and provides a good comparison with the ANN model in our context. We believe such insights will pave better way forward for the application of machine learning towards species identification and food safety.

MARS: a mouse atlas registration system based on a planar x-ray projector and an optical camera

NASA Astrophysics Data System (ADS)

Wang, Hongkai; Stout, David B.; Taschereau, Richard; Gu, Zheng; Vu, Nam T.; Prout, David L.; Chatziioannou, Arion F.

2012-10-01

This paper introduces a mouse atlas registration system (MARS), composed of a stationary top-view x-ray projector and a side-view optical camera, coupled to a mouse atlas registration algorithm. This system uses the x-ray and optical images to guide a fully automatic co-registration of a mouse atlas with each subject, in order to provide anatomical reference for small animal molecular imaging systems such as positron emission tomography (PET). To facilitate the registration, a statistical atlas that accounts for inter-subject anatomical variations was constructed based on 83 organ-labeled mouse micro-computed tomography (CT) images. The statistical shape model and conditional Gaussian model techniques were used to register the atlas with the x-ray image and optical photo. The accuracy of the atlas registration was evaluated by comparing the registered atlas with the organ-labeled micro-CT images of the test subjects. The results showed excellent registration accuracy of the whole-body region, and good accuracy for the brain, liver, heart, lungs and kidneys. In its implementation, the MARS was integrated with a preclinical PET scanner to deliver combined PET/MARS imaging, and to facilitate atlas-assisted analysis of the preclinical PET images.

MARS: a mouse atlas registration system based on a planar x-ray projector and an optical camera.

PubMed

Wang, Hongkai; Stout, David B; Taschereau, Richard; Gu, Zheng; Vu, Nam T; Prout, David L; Chatziioannou, Arion F

2012-10-07

This paper introduces a mouse atlas registration system (MARS), composed of a stationary top-view x-ray projector and a side-view optical camera, coupled to a mouse atlas registration algorithm. This system uses the x-ray and optical images to guide a fully automatic co-registration of a mouse atlas with each subject, in order to provide anatomical reference for small animal molecular imaging systems such as positron emission tomography (PET). To facilitate the registration, a statistical atlas that accounts for inter-subject anatomical variations was constructed based on 83 organ-labeled mouse micro-computed tomography (CT) images. The statistical shape model and conditional Gaussian model techniques were used to register the atlas with the x-ray image and optical photo. The accuracy of the atlas registration was evaluated by comparing the registered atlas with the organ-labeled micro-CT images of the test subjects. The results showed excellent registration accuracy of the whole-body region, and good accuracy for the brain, liver, heart, lungs and kidneys. In its implementation, the MARS was integrated with a preclinical PET scanner to deliver combined PET/MARS imaging, and to facilitate atlas-assisted analysis of the preclinical PET images.

A Multicriteria Approach to Find Predictive and Sparse Models with Stable Feature Selection for High-Dimensional Data.

PubMed

Bommert, Andrea; Rahnenführer, Jörg; Lang, Michel

2017-01-01

Finding a good predictive model for a high-dimensional data set can be challenging. For genetic data, it is not only important to find a model with high predictive accuracy, but it is also important that this model uses only few features and that the selection of these features is stable. This is because, in bioinformatics, the models are used not only for prediction but also for drawing biological conclusions which makes the interpretability and reliability of the model crucial. We suggest using three target criteria when fitting a predictive model to a high-dimensional data set: the classification accuracy, the stability of the feature selection, and the number of chosen features. As it is unclear which measure is best for evaluating the stability, we first compare a variety of stability measures. We conclude that the Pearson correlation has the best theoretical and empirical properties. Also, we find that for the stability assessment behaviour it is most important that a measure contains a correction for chance or large numbers of chosen features. Then, we analyse Pareto fronts and conclude that it is possible to find models with a stable selection of few features without losing much predictive accuracy.

Detecting Diseases in Medical Prescriptions Using Data Mining Tools and Combining Techniques.

PubMed

Teimouri, Mehdi; Farzadfar, Farshad; Soudi Alamdari, Mahsa; Hashemi-Meshkini, Amir; Adibi Alamdari, Parisa; Rezaei-Darzi, Ehsan; Varmaghani, Mehdi; Zeynalabedini, Aysan

2016-01-01

Data about the prevalence of communicable and non-communicable diseases, as one of the most important categories of epidemiological data, is used for interpreting health status of communities. This study aims to calculate the prevalence of outpatient diseases through the characterization of outpatient prescriptions. The data used in this study is collected from 1412 prescriptions for various types of diseases from which we have focused on the identification of ten diseases. In this study, data mining tools are used to identify diseases for which prescriptions are written. In order to evaluate the performances of these methods, we compare the results with Naïve method. Then, combining methods are used to improve the results. Results showed that Support Vector Machine, with an accuracy of 95.32%, shows better performance than the other methods. The result of Naive method, with an accuracy of 67.71%, is 20% worse than Nearest Neighbor method which has the lowest level of accuracy among the other classification algorithms. The results indicate that the implementation of data mining algorithms resulted in a good performance in characterization of outpatient diseases. These results can help to choose appropriate methods for the classification of prescriptions in larger scales.

Estimation of Center of Mass Trajectory using Wearable Sensors during Golf Swing.

PubMed

Najafi, Bijan; Lee-Eng, Jacqueline; Wrobel, James S; Goebel, Ruben

2015-06-01

This study suggests a wearable sensor technology to estimate center of mass (CoM) trajectory during a golf swing. Groups of 3, 4, and 18 participants were recruited, respectively, for the purpose of three validation studies. Study 1 examined the accuracy of the system to estimate a 3D body segment angle compared to a camera-based motion analyzer (Vicon®). Study 2 assessed the accuracy of three simplified CoM trajectory models. Finally, Study 3 assessed the accuracy of the proposed CoM model during multiple golf swings. A relatively high agreement was observed between wearable sensors and the reference (Vicon®) for angle measurement (r > 0.99, random error <1.2° (1.5%) for anterior-posterior; <0.9° (2%) for medial-lateral; and <3.6° (2.5%) for internal-external direction). The two-link model yielded a better agreement with the reference system compared to one-link model (r > 0.93 v. r = 0.52, respectively). On the same note, the proposed two-link model estimated CoM trajectory during golf swing with relatively good accuracy (r > 0.9, A-P random error <1cm (7.7%) and <2cm (10.4%) for M-L). The proposed system appears to accurately quantify the kinematics of CoM trajectory as a surrogate of dynamic postural control during an athlete's movement and its portability, makes it feasible to fit the competitive environment without restricting surface type. Key pointsThis study demonstrates that wearable technology based on inertial sensors are accurate to estimate center of mass trajectory in complex athletic task (e.g., golf swing)This study suggests that two-link model of human body provides optimum tradeoff between accuracy and minimum number of sensor module for estimation of center of mass trajectory in particular during fast movements.Wearable technologies based on inertial sensors are viable option for assessing dynamic postural control in complex task outside of gait laboratory and constraints of cameras, surface, and base of support.

Electroencephalography Predicts Poor and Good Outcomes After Cardiac Arrest: A Two-Center Study.

PubMed

Rossetti, Andrea O; Tovar Quiroga, Diego F; Juan, Elsa; Novy, Jan; White, Roger D; Ben-Hamouda, Nawfel; Britton, Jeffrey W; Oddo, Mauro; Rabinstein, Alejandro A

2017-07-01

The prognostic role of electroencephalography during and after targeted temperature management in postcardiac arrest patients, relatively to other predictors, is incompletely known. We assessed performances of electroencephalography during and after targeted temperature management toward good and poor outcomes, along with other recognized predictors. Cohort study (April 2009 to March 2016). Two academic hospitals (Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland; Mayo Clinic, Rochester, MN). Consecutive comatose adults admitted after cardiac arrest, identified through prospective registries. All patients were managed with targeted temperature management, receiving prespecified standardized clinical, neurophysiologic (particularly, electroencephalography during and after targeted temperature management), and biochemical evaluations. We assessed electroencephalography variables (reactivity, continuity, epileptiform features, and prespecified "benign" or "highly malignant" patterns based on the American Clinical Neurophysiology Society nomenclature) and other clinical, neurophysiologic (somatosensory-evoked potential), and biochemical prognosticators. Good outcome (Cerebral Performance Categories 1 and 2) and mortality predictions at 3 months were calculated. Among 357 patients, early electroencephalography reactivity and continuity and flexor or better motor reaction had greater than 70% positive predictive value for good outcome; reactivity (80.4%; 95% CI, 75.9-84.4%) and motor response (80.1%; 95% CI, 75.6-84.1%) had highest accuracy. Early benign electroencephalography heralded good outcome in 86.2% (95% CI, 79.8-91.1%). False positive rates for mortality were less than 5% for epileptiform or nonreactive early electroencephalography, nonreactive late electroencephalography, absent somatosensory-evoked potential, absent pupillary or corneal reflexes, presence of myoclonus, and neuron-specific enolase greater than 75 µg/L; accuracy was highest for early electroencephalography reactivity (86.6%; 95% CI, 82.6-90.0). Early highly malignant electroencephalography had an false positive rate of 1.5% with accuracy of 85.7% (95% CI, 81.7-89.2%). This study provides class III evidence that electroencephalography reactivity predicts both poor and good outcomes, and motor reaction good outcome after cardiac arrest. Electroencephalography reactivity seems to be the best discriminator between good and poor outcomes. Standardized electroencephalography interpretation seems to predict both conditions during and after targeted temperature management.

Accuracy of Rhenium-188 SPECT/CT activity quantification for applications in radionuclide therapy using clinical reconstruction methods.

PubMed

Esquinas, Pedro L; Uribe, Carlos F; Gonzalez, M; Rodríguez-Rodríguez, Cristina; Häfeli, Urs O; Celler, Anna

2017-07-20

The main applications of 188 Re in radionuclide therapies include trans-arterial liver radioembolization and palliation of painful bone-metastases. In order to optimize 188 Re therapies, the accurate determination of radiation dose delivered to tumors and organs at risk is required. Single photon emission computed tomography (SPECT) can be used to perform such dosimetry calculations. However, the accuracy of dosimetry estimates strongly depends on the accuracy of activity quantification in 188 Re images. In this study, we performed a series of phantom experiments aiming to investigate the accuracy of activity quantification for 188 Re SPECT using high-energy and medium-energy collimators. Objects of different shapes and sizes were scanned in Air, non-radioactive water (Cold-water) and water with activity (Hot-water). The ordered subset expectation maximization algorithm with clinically available corrections (CT-based attenuation, triple-energy window (TEW) scatter and resolution recovery was used). For high activities, the dead-time corrections were applied. The accuracy of activity quantification was evaluated using the ratio of the reconstructed activity in each object to this object's true activity. Each object's activity was determined with three segmentation methods: a 1% fixed threshold (for cold background), a 40% fixed threshold and a CT-based segmentation. Additionally, the activity recovered in the entire phantom, as well as the average activity concentration of the phantom background were compared to their true values. Finally, Monte-Carlo simulations of a commercial [Formula: see text]-camera were performed to investigate the accuracy of the TEW method. Good quantification accuracy (errors  <10%) was achieved for the entire phantom, the hot-background activity concentration and for objects in cold background segmented with a 1% threshold. However, the accuracy of activity quantification for objects segmented with 40% threshold or CT-based methods decreased (errors  >15%), mostly due to partial-volume effects. The Monte-Carlo simulations confirmed that TEW-scatter correction applied to 188 Re, although practical, yields only approximate estimates of the true scatter.

A robust omnifont open-vocabulary Arabic OCR system using pseudo-2D-HMM

NASA Astrophysics Data System (ADS)

Rashwan, Abdullah M.; Rashwan, Mohsen A.; Abdel-Hameed, Ahmed; Abdou, Sherif; Khalil, A. H.

2012-01-01

Recognizing old documents is highly desirable since the demand for quickly searching millions of archived documents has recently increased. Using Hidden Markov Models (HMMs) has been proven to be a good solution to tackle the main problems of recognizing typewritten Arabic characters. These attempts however achieved a remarkable success for omnifont OCR under very favorable conditions, they didn't achieve the same performance in practical conditions, i.e. noisy documents. In this paper we present an omnifont, large-vocabulary Arabic OCR system using Pseudo Two Dimensional Hidden Markov Model (P2DHMM), which is a generalization of the HMM. P2DHMM offers a more efficient way to model the Arabic characters, such model offer both minimal dependency on the font size/style (omnifont), and high level of robustness against noise. The evaluation results of this system are very promising compared to a baseline HMM system and best OCRs available in the market (Sakhr and NovoDynamics). The recognition accuracy of the P2DHMM classifier is measured against the classic HMM classifier, the average word accuracy rates for P2DHMM and HMM classifiers are 79% and 66% respectively. The overall system accuracy is measured against Sakhr and NovoDynamics OCR systems, the average word accuracy rates for P2DHMM, NovoDynamics, and Sakhr are 74%, 71%, and 61% respectively.

Analytical performance, agreement and user-friendliness of six point-of-care testing urine analysers for urinary tract infection in general practice

PubMed Central

Schot, Marjolein J C; van Delft, Sanne; Kooijman-Buiting, Antoinette M J; de Wit, Niek J; Hopstaken, Rogier M

2015-01-01

Objective Various point-of-care testing (POCT) urine analysers are commercially available for routine urine analysis in general practice. The present study compares analytical performance, agreement and user-friendliness of six different POCT urine analysers for diagnosing urinary tract infection in general practice. Setting All testing procedures were performed at a diagnostic centre for primary care in the Netherlands. Urine samples were collected at four general practices. Primary and secondary outcome measures Analytical performance and agreement of the POCT analysers regarding nitrite, leucocytes and erythrocytes, with the laboratory reference standard, was the primary outcome measure, and analysed by calculating sensitivity, specificity, positive and negative predictive value, and Cohen's κ coefficient for agreement. Secondary outcome measures were the user-friendliness of the POCT analysers, in addition to other characteristics of the analysers. Results The following six POCT analysers were evaluated: Uryxxon Relax (Macherey Nagel), Urisys 1100 (Roche), Clinitek Status (Siemens), Aution 11 (Menarini), Aution Micro (Menarini) and Urilyzer (Analyticon). Analytical performance was good for all analysers. Compared with laboratory reference standards, overall agreement was good, but differed per parameter and per analyser. Concerning the nitrite test, the most important test for clinical practice, all but one showed perfect agreement with the laboratory standard. For leucocytes and erythrocytes specificity was high, but sensitivity was considerably lower. Agreement for leucocytes varied between good to very good, and for the erythrocyte test between fair and good. First-time users indicated that the analysers were easy to use. They expected higher productivity and accuracy when using these analysers in daily practice. Conclusions The overall performance and user-friendliness of all six commercially available POCT urine analysers was sufficient to justify routine use in suspected urinary tract infections in general practice. PMID:25986635

Assessment of liver ablation using cone beam computed tomography.

PubMed

Abdel-Rehim, Mohamed; Ronot, Maxime; Sibert, Annie; Vilgrain, Valérie

2015-01-14

To investigate the feasibility and accuracy of cone beam computed tomography (CBCT) in assessing the ablation zone after liver tumor ablation. Twenty-three patients (17 men and 6 women, range: 45-85 years old, mean age 65 years) with malignant liver tumors underwent ultrasound-guided percutaneous tumor ablation [radiofrequency (n = 14), microwave (n = 9)] followed by intravenous contrast-enhanced CBCT. Baseline multidetector computed tomography (MDCT) and peri-procedural CBCT images were compared. CBCT image quality was assessed as poor, good, or excellent. Image fusion was performed to assess tumor coverage, and quality of fusion was rated as bad, good, or excellent. Ablation zone volumes on peri-procedural CBCT and post-procedural MDCT were compared using the non-parametric paired Wilcoxon t-test. Rate of primary ablation effectiveness was 100%. There were no complications related to ablation. Local tumor recurrence and new liver tumors were found 3 mo after initial treatment in one patient (4%). The ablation zone was identified in 21/23 (91.3%) patients on CBCT. The fusion of baseline MDCT and peri-procedural CBCT images was feasible in all patients and showed satisfactory tumor coverage (at least 5-mm margin). CBCT image quality was poor, good, and excellent in 2 (9%), 8 (35%), and 13 (56%), patients respectively. Registration quality between peri-procedural CBCT and post-procedural MDCT images was good to excellent in 17/23 (74%) patients. The median ablation volume on peri-procedural CBCT and post-procedural MDCT was 30 cm(3) (range: 4-95 cm(3)) and 30 cm(3) (range: 4-124 cm(3)), respectively (P-value > 0.2). There was a good correlation (r = 0.79) between the volumes of the two techniques. Contrast-enhanced CBCT after tumor ablation of the liver allows early assessment of the ablation zone.

Diagnostic validity of methods for assessment of swallowing sounds: a systematic review.

PubMed

Taveira, Karinna Veríssimo Meira; Santos, Rosane Sampaio; Leão, Bianca Lopes Cavalcante de; Neto, José Stechman; Pernambuco, Leandro; Silva, Letícia Korb da; De Luca Canto, Graziela; Porporatti, André Luís

2018-02-03

Oropharyngeal dysphagia is a highly prevalent comorbidity in neurological patients and presents a serious health threat, which may lead to outcomes of aspiration pneumonia, ranging from hospitalization to death. This assessment proposes a non-invasive, acoustic-based method to differentiate between individuals with and without signals of penetration and aspiration. This systematic review evaluated the diagnostic validity of different methods for assessment of swallowing sounds, when compared to Videofluroscopic of Swallowing Study (VFSS) to detect oropharyngeal dysphagia. Articles in which the primary objective was to evaluate the accuracy of swallowing sounds were searched in five electronic databases with no language or time limitations. Accuracy measurements described in the studies were transformed to construct receiver operating characteristic curves and forest plots with the aid of Review Manager v. 5.2 (The Nordic Cochrane Centre, Copenhagen, Denmark). The methodology of the selected studies was evaluated using the Quality Assessment Tool for Diagnostic Accuracy Studies-2. The final electronic search revealed 554 records, however only 3 studies met the inclusion criteria. The accuracy values (area under the curve) were 0.94 for microphone, 0.80 for Doppler, and 0.60 for stethoscope. Based on limited evidence and low methodological quality because few studies were included, with a small sample size, from all index testes found for this systematic review, Doppler showed excellent diagnostic accuracy for the discrimination of swallowing sounds, whereas microphone-reported good accuracy discrimination of swallowing sounds of dysphagic patients and stethoscope showed best screening test. Copyright © 2018 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Diagnostic accuracy of noncontrast MRI for detection of glenohumeral cartilage lesions: a prospective comparison to arthroscopy.

PubMed

VanBeek, Corinne; Loeffler, Bryan J; Narzikul, Alexa; Gordon, Victoria; Rasiej, Michael J; Kazam, Jonathan K; Abboud, Joseph A

2014-07-01

The purpose of this study was to determine the prevalence of glenohumeral articular cartilage lesions in patients with rotator cuff tendinopathy and to assess the accuracy of noncontrast magnetic resonance imaging (MRI) in detecting these defects compared with the "gold standard" of arthroscopy. Noncontrast MRI studies obtained in 84 consecutive patients undergoing shoulder arthroscopy for rotator cuff tendinopathy (mean age, 54.8 years; range, 17-82 years) were prospectively evaluated for glenohumeral cartilage lesions. Two fellowship-trained, experienced musculoskeletal radiologists were blinded from the arthroscopic findings and independently evaluated the glenoid and humeral head cartilage on 2 separate occasions. At arthroscopy, cartilage lesions of the humeral head were detected in 23 patients (frequency, 27.4%), and glenoid cartilage lesions were found in 20 patients (frequency, 23.8%). For detection of a humeral lesion on MRI, the radiologists' combined accuracy was 78%, sensitivity was 43%, and specificity was 91%. The combined accuracy for detection of glenoid lesions on MRI was 84%, sensitivity was 53%, and specificity was 93%. Combining the readers, low-grade lesions (International Cartilage Repair Society grades 1 and 2) of the glenoid and humerus were read as negative on MRI in 63% and 86% of cases, respectively. Overall accuracy of noncontrast MRI for detection of glenohumeral articular cartilage lesions is good; however, interpretation is reader dependent, and accuracy is significantly reduced for detection of low-grade lesions. On the basis of these findings, we recommend that patients with rotator cuff tendinopathy undergoing arthroscopy be informed that the presence and severity of cartilage lesions may be underestimated on MRI. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Place and response learning in human virtual navigation: behavioral measures and gender differences.

PubMed

Schmitzer-Torbert, Neil

2007-04-01

Two experiments examined the use of place and response strategies by humans navigating virtual multiple T mazes. In Experiment 1, probe trials revealed that participants commonly used place and response strategies, and place strategies were more frequent early in training, whereas response strategies were more frequent late in training. Compared with women, men learned the correct path through the maze more quickly and developed a more stable route through the maze. In Experiment 2, participants were trained to locate 2 targets. One target required participants to use either a place or response strategy, whereas the other target could be found using either strategy. Accuracy improved faster for place training compared with response training, and women outperformed men in both groups. Probe trials testing transfer of the imposed strategy to the other target found faster transfer for place training than for response training and that women demonstrated faster transfer than men. Accuracy on probe trials was correlated with poor route stability in the place-trained group and with good route stability in the response-trained group, indicating that navigation strategy use may be related to measures of improvement in performance on normal trials. (c) 2007 APA, all rights reserved

Comparison of transabdominal and transvaginal sonography in the diagnosis of placenta previa.

PubMed

Petpichetchian, Chusana; Pranpanus, Savitree; Suntharasaj, Thitima; Kor-Anantakul, Ounjai; Hanprasertpong, Tharangrut

2018-07-01

To compare the accuracies of transabdominal sonography (TAS) and transvaginal sonography (TVS) in the diagnosis of placenta previa. A prospective, cross-sectional study was conducted at a university hospital. Both TAS and TVS were performed on 81 pregnant women with a suspicion of placenta previa in the third trimester. The final diagnosis was confirmed at delivery. The agreement between the two ultrasound methods and the parameters of each method were calculated. Fifty-eight percent of the women had a placenta previa. The sensitivities of TAS and TVS were 86% (95% CI 78-94%) and 95% (95% CI 91-100%), respectively (p= 0.2). The specificity of both methods was 93% (95 CI 88-99%), and the overall accuracies of TAS and TVS were 89% (95% CI 82-96%) and 94% (95% CI 89-100%), respectively. When TAS was followed by TVS, 23% of the previous diagnoses were changed. The agreement between both methods was good (Kappa value = 0.7, 95%CI 0.55-0.86). For the diagnosis of placenta previa, TAS showed a high sensitivity and specificity, which were comparable to those of TVS. © 2018 Wiley Periodicals, Inc.

RMP: Reduced-set matching pursuit approach for efficient compressed sensing signal reconstruction.

PubMed

Abdel-Sayed, Michael M; Khattab, Ahmed; Abu-Elyazeed, Mohamed F

2016-11-01

Compressed sensing enables the acquisition of sparse signals at a rate that is much lower than the Nyquist rate. Compressed sensing initially adopted [Formula: see text] minimization for signal reconstruction which is computationally expensive. Several greedy recovery algorithms have been recently proposed for signal reconstruction at a lower computational complexity compared to the optimal [Formula: see text] minimization, while maintaining a good reconstruction accuracy. In this paper, the Reduced-set Matching Pursuit (RMP) greedy recovery algorithm is proposed for compressed sensing. Unlike existing approaches which either select too many or too few values per iteration, RMP aims at selecting the most sufficient number of correlation values per iteration, which improves both the reconstruction time and error. Furthermore, RMP prunes the estimated signal, and hence, excludes the incorrectly selected values. The RMP algorithm achieves a higher reconstruction accuracy at a significantly low computational complexity compared to existing greedy recovery algorithms. It is even superior to [Formula: see text] minimization in terms of the normalized time-error product, a new metric introduced to measure the trade-off between the reconstruction time and error. RMP superior performance is illustrated with both noiseless and noisy samples.

A Cross-Correlated Delay Shift Supervised Learning Method for Spiking Neurons with Application to Interictal Spike Detection in Epilepsy.

PubMed

Guo, Lilin; Wang, Zhenzhong; Cabrerizo, Mercedes; Adjouadi, Malek

2017-05-01

This study introduces a novel learning algorithm for spiking neurons, called CCDS, which is able to learn and reproduce arbitrary spike patterns in a supervised fashion allowing the processing of spatiotemporal information encoded in the precise timing of spikes. Unlike the Remote Supervised Method (ReSuMe), synapse delays and axonal delays in CCDS are variants which are modulated together with weights during learning. The CCDS rule is both biologically plausible and computationally efficient. The properties of this learning rule are investigated extensively through experimental evaluations in terms of reliability, adaptive learning performance, generality to different neuron models, learning in the presence of noise, effects of its learning parameters and classification performance. Results presented show that the CCDS learning method achieves learning accuracy and learning speed comparable with ReSuMe, but improves classification accuracy when compared to both the Spike Pattern Association Neuron (SPAN) learning rule and the Tempotron learning rule. The merit of CCDS rule is further validated on a practical example involving the automated detection of interictal spikes in EEG records of patients with epilepsy. Results again show that with proper encoding, the CCDS rule achieves good recognition performance.

Investigation of a Coupled Arrhenius-Type/Rossard Equation of AH36 Material

PubMed Central

Qin, Qin; Tian, Ming-Liang; Zhang, Peng

2017-01-01

High-temperature tensile testing of AH36 material in a wide range of temperatures (1173–1573 K) and strain rates (10−4–10−2 s−1) has been obtained by using a Gleeble system. These experimental stress-strain data have been adopted to develop the constitutive equation. The constitutive equation of AH36 material was suggested based on the modified Arrhenius-type equation and the modified Rossard equation respectively. The results indicate that the constitutive equation is strongly influenced by temperature and strain, especially strain. Moreover, there is a good agreement between the predicted data of the modified Arrhenius-type equation and the experimental results when the strain is greater than 0.02. There is also good agreement between the predicted data of the Rossard equation and the experimental results when the strain is less than 0.02. Therefore, a coupled equation where the modified Arrhenius-type equation and Rossard equation are combined has been proposed to describe the constitutive equation of AH36 material according to the different strain values in order to improve the accuracy. The correlation coefficient between the computed and experimental flow stress data was 0.998. The minimum value of the average absolute relative error shows the high accuracy of the coupled equation compared with the two modified equations. PMID:28772767

Application of portable X-ray fluorescence spectrometry in environmental investigation of heavy metal-contaminated sites and comparison with laboratory analysis

NASA Astrophysics Data System (ADS)

Ding, Liang; Wang, Shui; Cai, Bingjie; Zhang, Mancheng; Qu, Changsheng

2018-02-01

In this study, portable X-ray fluorescence spectrometry (pXRF) was used to measure the heavy metal contents of As, Cu, Cr, Ni, Pb and Zn in the soils of heavy metal-contaminated sites. The precision, accuracy and system errors of pXRF were evaluated and compared with traditional laboratory methods to examine the suitability of in situ pXRF. The results show that the pXRF analysis achieved satisfactory accuracy and precision in measuring As, Cr, Cu, Ni, Pb, and Zn in soils, and meets the requirements of the relevant detection technology specifications. For the certified reference soil samples, the pXRF results of As, Cr, Cu, Ni, Pb, and Zn show good linear relationships and coefficients of determination with the values measured using the reference analysis methods; with the exception of Ni, all the measured values were within the 95% confidence level. In the soil samples, the coefficients of determination between Cu, Zn, Pb, and Ni concentrations measured laboratory pXRF and the values measured with laboratory analysis all reach 0.9, showing a good linear relationship; however, there were large deviations between methods for Cr and As. This study provides reference data and scientific support for rapid detection of heavy metals in soils using pXRF in site investigation, which can better guide the practical application of pXRF.

Simultaneous Determination of Metamizole, Thiamin and Pyridoxin Using UV-Spectroscopy in Combination with Multivariate Calibration

PubMed Central

Chotimah, Chusnul; Sudjadi; Riyanto, Sugeng; Rohman, Abdul

2015-01-01

Purpose: Analysis of drugs in multicomponent system officially is carried out using chromatographic technique, however, this technique is too laborious and involving sophisticated instrument. Therefore, UV-VIS spectrophotometry coupled with multivariate calibration of partial least square (PLS) for quantitative analysis of metamizole, thiamin and pyridoxin is developed in the presence of cyanocobalamine without any separation step. Methods: The calibration and validation samples are prepared. The calibration model is prepared by developing a series of sample mixture consisting these drugs in certain proportion. Cross validation of calibration sample using leave one out technique is used to identify the smaller set of components that provide the greatest predictive ability. The evaluation of calibration model was based on the coefficient of determination (R2) and root mean square error of calibration (RMSEC). Results: The results showed that the coefficient of determination (R2) for the relationship between actual values and predicted values for all studied drugs was higher than 0.99 indicating good accuracy. The RMSEC values obtained were relatively low, indicating good precision. The accuracy and presision results of developed method showed no significant difference compared to those obtained by official method of HPLC. Conclusion: The developed method (UV-VIS spectrophotometry in combination with PLS) was succesfully used for analysis of metamizole, thiamin and pyridoxin in tablet dosage form. PMID:26819934

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

Nakaguchi, Yuji, E-mail: nkgc2003@yahoo.co.jp; Ono, Takeshi; Onitsuka, Ryota

COMPASS system (IBA Dosimetry, Schwarzenbruck, Germany) and ArcCHECK with 3DVH software (Sun Nuclear Corp., Melbourne, FL) are commercial quasi-3-dimensional (3D) dosimetry arrays. Cross-validation to compare them under the same conditions, such as a treatment plan, allows for clear evaluation of such measurement devices. In this study, we evaluated the accuracy of reconstructed dose distributions from the COMPASS system and ArcCHECK with 3DVH software using Monte Carlo simulation (MC) for multi-leaf collimator (MLC) test patterns and clinical VMAT plans. In a phantom study, ArcCHECK 3DVH showed clear differences from COMPASS, measurement and MC due to the detector resolution and the dosemore » reconstruction method. Especially, ArcCHECK 3DVH showed 7% difference from MC for the heterogeneous phantom. ArcCHECK 3DVH only corrects the 3D dose distribution of treatment planning system (TPS) using ArcCHECK measurement, and therefore the accuracy of ArcCHECK 3DVH depends on TPS. In contrast, COMPASS showed good agreement with MC for all cases. However, the COMPASS system requires many complicated installation procedures such as beam modeling, and appropriate commissioning is needed. In terms of clinical cases, there were no large differences for each QA device. The accuracy of the compass and ArcCHECK 3DVH systems for phantoms and clinical cases was compared. Both systems have advantages and disadvantages for clinical use, and consideration of the operating environment is important. The QA system selection is depending on the purpose and workflow in each hospital.« less

Convolutional neural networks for vibrational spectroscopic data analysis.

PubMed

Acquarelli, Jacopo; van Laarhoven, Twan; Gerretzen, Jan; Tran, Thanh N; Buydens, Lutgarde M C; Marchiori, Elena

2017-02-15

In this work we show that convolutional neural networks (CNNs) can be efficiently used to classify vibrational spectroscopic data and identify important spectral regions. CNNs are the current state-of-the-art in image classification and speech recognition and can learn interpretable representations of the data. These characteristics make CNNs a good candidate for reducing the need for preprocessing and for highlighting important spectral regions, both of which are crucial steps in the analysis of vibrational spectroscopic data. Chemometric analysis of vibrational spectroscopic data often relies on preprocessing methods involving baseline correction, scatter correction and noise removal, which are applied to the spectra prior to model building. Preprocessing is a critical step because even in simple problems using 'reasonable' preprocessing methods may decrease the performance of the final model. We develop a new CNN based method and provide an accompanying publicly available software. It is based on a simple CNN architecture with a single convolutional layer (a so-called shallow CNN). Our method outperforms standard classification algorithms used in chemometrics (e.g. PLS) in terms of accuracy when applied to non-preprocessed test data (86% average accuracy compared to the 62% achieved by PLS), and it achieves better performance even on preprocessed test data (96% average accuracy compared to the 89% achieved by PLS). For interpretability purposes, our method includes a procedure for finding important spectral regions, thereby facilitating qualitative interpretation of results. Copyright © 2016 Elsevier B.V. All rights reserved.

Can electromagnetic-navigated maxillary positioning replace occlusional splints in orthognathic surgery? A clinical pilot study.

PubMed

Berger, Moritz; Nova, Igor; Kallus, Sebastian; Ristow, Oliver; Freudlsperger, Christian; Eisenmann, Urs; Dickhaus, Hartmut; Engel, Michael; Hoffmann, Jürgen; Seeberger, Robin

2017-10-01

Because of the inaccuracy of intermaxillary splints in orthognathic surgery, intraoperative guidance via a real time navigation system might represent a suitable method for enhancing the precision of maxillary positioning. Therefore, in this clinical trial, maxillary repositioning after Le Fort I osteotomy was guided splintless by an electromagnetic navigation system. Conservatively planned maxillary reposition in each of 5 patients was transferred to a novel software module of the electromagnetic navigation system. Intraoperatively, after Le Fort I osteotomy, the software guided the maxilla to the targeted position. Accuracy was evaluated by pre- and postoperative cone beam computer tomography imaging (the vectorial distance of the incisal marker points was measured in three dimensions) and compared with that of a splint transposed control group. The repositioning of the maxilla guided by the electromagnetic navigation system was intuitive and simple to accomplish. The achieved maxillary position with a deviation of 0.7 mm on average to the planned position was equally accurate compared with that of the splint transposed control group of 0.5 mm (p > 0.05). The data of this clinical study display good accuracy for splintless electromagnetic-navigated maxillary positioning. Nevertheless, this method does not surpass the splint-encoded gold standard with regard to accuracy. Future investigations will be necessary to show the full potential of electromagnetic navigation in orthognathic surgery. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Accuracy and stability of measuring GABA, glutamate, and glutamine by proton magnetic resonance spectroscopy: A phantom study at 4 Tesla

NASA Astrophysics Data System (ADS)

Henry, Michael E.; Lauriat, Tara L.; Shanahan, Meghan; Renshaw, Perry F.; Jensen, J. Eric

2011-02-01

Proton magnetic resonance spectroscopy has the potential to provide valuable information about alterations in gamma-aminobutyric acid (GABA), glutamate (Glu), and glutamine (Gln) in psychiatric and neurological disorders. In order to use this technique effectively, it is important to establish the accuracy and reproducibility of the methodology. In this study, phantoms with known metabolite concentrations were used to compare the accuracy of 2D J-resolved MRS, single-echo 30 ms PRESS, and GABA-edited MEGA-PRESS for measuring all three aforementioned neurochemicals simultaneously. The phantoms included metabolite concentrations above and below the physiological range and scans were performed at baseline, 1 week, and 1 month time-points. For GABA measurement, MEGA-PRESS proved optimal with a measured-to-target correlation of R2 = 0.999, with J-resolved providing R2 = 0.973 for GABA. All three methods proved effective in measuring Glu with R2 = 0.987 (30 ms PRESS), R2 = 0.996 (J-resolved) and R2 = 0.910 (MEGA-PRESS). J-resolved and MEGA-PRESS yielded good results for Gln measures with respective R2 = 0.855 (J-resolved) and R2 = 0.815 (MEGA-PRESS). The 30 ms PRESS method proved ineffective in measuring GABA and Gln. When measurement stability at in vivo concentration was assessed as a function of varying spectral quality, J-resolved proved the most stable and immune to signal-to-noise and linewidth fluctuation compared to MEGA-PRESS and 30 ms PRESS.

A B-spline Galerkin method for the Dirac equation

NASA Astrophysics Data System (ADS)

Froese Fischer, Charlotte; Zatsarinny, Oleg

2009-06-01

The B-spline Galerkin method is first investigated for the simple eigenvalue problem, y=-λy, that can also be written as a pair of first-order equations y=λz, z=-λy. Expanding both y(r) and z(r) in the B basis results in many spurious solutions such as those observed for the Dirac equation. However, when y(r) is expanded in the B basis and z(r) in the dB/dr basis, solutions of the well-behaved second-order differential equation are obtained. From this analysis, we propose a stable method ( B,B) basis for the Dirac equation and evaluate its accuracy by comparing the computed and exact R-matrix for a wide range of nuclear charges Z and angular quantum numbers κ. When splines of the same order are used, many spurious solutions are found whereas none are found for splines of different order. Excellent agreement is obtained for the R-matrix and energies for bound states for low values of Z. For high Z, accuracy requires the use of a grid with many points near the nucleus. We demonstrate the accuracy of the bound-state wavefunctions by comparing integrals arising in hyperfine interaction matrix elements with exact analytic expressions. We also show that the Thomas-Reiche-Kuhn sum rule is not a good measure of the quality of the solutions obtained by the B-spline Galerkin method whereas the R-matrix is very sensitive to the appearance of pseudo-states.

Towards more efficient burn care: Identifying factors associated with good quality of life post-burn.

PubMed

Finlay, V; Phillips, M; Allison, G T; Wood, F M; Ching, D; Wicaksono, D; Plowman, S; Hendrie, D; Edgar, D W

2015-11-01

As minor burn patients constitute the vast majority of a developed nation case-mix, streamlining care for this group can promote efficiency from a service-wide perspective. This study tested the hypothesis that a predictive nomogram model that estimates likelihood of good long-term quality of life (QoL) post-burn is a valid way to optimise patient selection and risk management when applying a streamlined model of care. A sample of 224 burn patients managed by the Burn Service of Western Australia who provided both short and long-term outcomes was used to estimate the probability of achieving a good QoL defined as 150 out of a possible 160 points on the Burn Specific Health Scale-Brief (BSHS-B) at least six months from injury. A multivariate logistic regression analysis produced a predictive model provisioned as a nomogram for clinical application. A second, independent cohort of consecutive patients (n=106) was used to validate the predictive merit of the nomogram. Male gender (p=0.02), conservative management (p=0.03), upper limb burn (p=0.04) and high BSHS-B score within one month of burn (p<0.001) were significant predictors of good outcome at six months and beyond. A Receiver Operating Curve (ROC) analysis demonstrated excellent (90%) accuracy overall. At 80% probability of good outcome, the false positive risk was 14%. The nomogram was validated by running a second ROC analysis of the model in an independent cohort. The analysis confirmed high (86%) overall accuracy of the model, the risk of false positive was reduced to 10% at a lower (70%) probability. This affirms the stability of the nomogram model in different patient groups over time. An investigation of the effect of missing data on sample selection determined that a greater proportion of younger patients with smaller TBSA burns were excluded due to loss to follow up. For clinicians managing comparable burn populations, the BSWA burns nomogram is an effective tool to assist the selection of patients to a streamlined care pathway with the aim of improving efficiency of service delivery. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

A novel modality for intrapartum fetal heart rate monitoring.

PubMed

Ashwal, Eran; Shinar, Shiri; Aviram, Amir; Orbach, Sharon; Yogev, Yariv; Hiersch, Liran

2017-11-02

Intrapartum fetal heart rate (FHR) monitoring is well recommended during labor to assess fetal wellbeing. Though commonly used, the external Doppler and fetal scalp electrode monitor have significant shortcomings. Lately, non-invasive technologies were developed as possible alternatives. The objective of this study is to compare the accuracy of FHR trace using novel Electronic Uterine Monitoring (EUM) to that of external Doppler and fetal scalp electrode monitor. A comparative study conducted in a single tertiary medical center. Intrapartum FHR trace was recorded simultaneously using three different methods: internal fetal scalp electrode, external Doppler, and EUM. The latter, a multichannel electromyogram (EMG) device acquires a uterine signal and maternal and fetal electrocardiograms. FHR traces obtained from all devices during the first and second stages of labor were analyzed. Positive percent of agreement (PPA) and accuracy (by measuring root means square error between observed and predicted values) of EUM and external Doppler were both compared to internal scalp electrode monitoring. A Bland-Altman agreement plot was used to compare the differences in FHR trace between all modalities. For momentary recordings of fetal heart rate <110 bpm or >160 bpm level of agreement, sensitivity, and specificity were also evaluated. Overall, 712,800 FHR momentary recordings were obtained from 33 parturients. Although both EUM and external Doppler highly correlated with internal scalp electrode monitoring (r 2  = 0.98, p < .001 for both methods), the accuracy of EUM was significantly higher than external Doppler (99.0% versus 96.6%, p < .001). In addition, for fetal heart rate <110 bpm or >160 bpm, the PPA, sensitivity, and specificity of EUM as compared with internal fetal scalp electrode, were significantly greater than those of external Doppler (p < .001). Intrapartum FHR using EUM is both valid and accurate, yielding higher correlations with internal scalp electrode monitoring than external Doppler. As such, it may provide a good framework for non-invasive evaluation of intrapartum FHR.

Comparative evaluation of Indian Diabetes Risk Score and Finnish Diabetes Risk Score for predicting risk of diabetes mellitus type II: A teaching hospital-based survey in Maharashtra.

PubMed

Pawar, Shivshakti D; Naik, Jayashri D; Prabhu, Priya; Jatti, Gajanan M; Jadhav, Sachin B; Radhe, B K

2017-01-01

India is currently becoming capital for diabetes mellitus. This significantly increasing incidence of diabetes putting an additional burden on health care in India. Unfortunately, half of diabetic individuals are unknown about their diabetic status. Hence, there is an emergent need of effective screening instrument to identify "diabetes risk" individuals. The aim is to evaluate and compare the diagnostic accuracy and clinical utility of Indian Diabetes Risk Score (IDRS) and Finnish Diabetes Risk Score (FINDRISC). This is retrospective, record-based study of diabetes detection camp organized by a teaching hospital. Out of 780 people attended this camp voluntarily only 763 fulfilled inclusion criteria of the study. In this camp, pro forma included the World Health Organization STEP guidelines for surveillance of noncommunicable diseases. Included primary sociodemographic characters, physical measurements, and clinical examination. After that followed the random blood glucose estimation of each individual. Diagnostic accuracy of IDRS and FINDRISC compared by using receiver operative characteristic curve (ROC). Sensitivity, specificity, likelihood ratio, positive predictive and negative predictive values were compared. Clinical utility index (CUI) of each score also compared. SPSS version 22, Stata 13, R3.2.9 used. Out of 763 individuals, 38 were new diabetics. By IDRS 347 and by FINDRISC 96 people were included in high-risk category for diabetes. Odds ratio for high-risk people in FINDRISC for getting affected by diabetes was 10.70. Similarly, it was 4.79 for IDRS. Area under curves of ROCs of both scores were indifferent ( P = 0.98). Sensitivity and specificity of IDRS was 78.95% and 56.14%; whereas for FINDRISC it was 55.26% and 89.66%, respectively. CUI was excellent (0.86) for FINDRISC while IDRS it was "satisfactory" (0.54). Bland-Altman plot and Cohen's Kappa suggested fair agreement between these score in measuring diabetes risk. Diagnostic accuracy and clinical utility of FINDRISC is fairly good than IDRS.

A whole-heart motion-correction algorithm: Effects on CT image quality and diagnostic accuracy of mechanical valve prosthesis abnormalities.

PubMed

Suh, Young Joo; Kim, Young Jin; Kim, Jin Young; Chang, Suyon; Im, Dong Jin; Hong, Yoo Jin; Choi, Byoung Wook

2017-11-01

We aimed to determine the effect of a whole-heart motion-correction algorithm (new-generation snapshot freeze, NG SSF) on the image quality of cardiac computed tomography (CT) images in patients with mechanical valve prostheses compared to standard images without motion correction and to compare the diagnostic accuracy of NG SSF and standard CT image sets for the detection of prosthetic valve abnormalities. A total of 20 patients with 32 mechanical valves who underwent wide-coverage detector cardiac CT with single-heartbeat acquisition were included. The CT image quality for subvalvular (below the prosthesis) and valvular regions (valve leaflets) of mechanical valves was assessed by two observers on a four-point scale (1 = poor, 2 = fair, 3 = good, and 4 = excellent). Paired t-tests or Wilcoxon signed rank tests were used to compare image quality scores and the number of diagnostic phases (image quality score≥3) between the standard image sets and NG SSF image sets. Diagnostic performance for detection of prosthetic valve abnormalities was compared between two image sets with the final diagnosis set by re-operation or clinical findings as the standard reference. NG SSF image sets had better image quality scores than standard image sets for both valvular and subvalvular regions (P < 0.05 for both). The number of phases that were of diagnostic image quality per patient was significantly greater in the NG SSF image set than standard image set for both valvular and subvalvular regions (P < 0.0001). Diagnostic performance of NG SSF image sets for the detection of prosthetic abnormalities (20 pannus and two paravalvular leaks) was greater than that of standard image sets (P < 0.05). Application of NG SSF can improve CT image quality and diagnostic accuracy in patients with mechanical valves compared to standard images. Copyright © 2017 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Examining the strength of the newly-launched Sentinel 2 MSI sensor in detecting and discriminating subtle differences between C3 and C4 grass species

NASA Astrophysics Data System (ADS)

Shoko, C.; Mutanga, O.

2017-07-01

C3 and C4 grass species discrimination has increasingly become relevant in understanding their response to environmental changes and to monitor their integrity in providing goods and services. While remotely-sensed data provide robust, cost-effective and repeatable monitoring tools for C3 and C4 grasses, this has been largely limited by the scarcity of sensors with better earth imaging characteristics. The recent launch of the advanced Sentinel 2 MultiSpectral Instrument (MSI) presents a new prospect for discriminating C3 and C4 grasses. The present study tested the potential of Sentinel 2, characterized by refined spatial resolution and more unique spectral bands in discriminating between Festuca (C3) and Themeda (C4) grasses. To evaluate the performance of Sentinel 2 MSI; spectral bands, vegetation indices and spectral bands plus indices were used. Findings from Sentinel 2 were compared with those derived from the widely-used Worldview 2 commercial sensor and the Landsat 8 Operational Land Imager (OLI). Overall classification accuracies have shown that Sentinel 2 bands have potential (90.36%), than indices (85.54%) and combined variables (88.61%). The results were comparable to Worldview 2 sensor, which produced slightly higher accuracies using spectral bands (95.69%), indices (86.02%) and combined variables (87.09%), and better than Landsat 8 OLI spectral bands (75.26%), indices (82.79%) and combined variables (86.02%). Sentinel 2 bands produced lower errors of commission and omission (between 4.76 and 14.63%), comparable to Worldview 2 (between 1.96 and 7.14%), than Landsat 8 (between 18.18 and 30.61%), when classifying the two species. The classification accuracy from Sentinel 2 also did not differ significantly (z = 1.34) from Worldview 2, using standard bands; it was significantly (z > 1.96) different using indices and combined variables, whereas when compared to Landsat 8, Sentinel 2 accuracies were significantly different (z > 1.96) using all variables. These results demonstrated that key vegetation species discrimination could be improved by the use of the freely and improved Sentinel 2 MSI data.

GOODS-Herschel: identification of the individual galaxies responsible for the 80-290 μm cosmic infrared background

NASA Astrophysics Data System (ADS)

Leiton, R.; Elbaz, D.; Okumura, K.; Hwang, H. S.; Magdis, G.; Magnelli, B.; Valtchanov, I.; Dickinson, M.; Béthermin, M.; Schreiber, C.; Charmandaris, V.; Dole, H.; Juneau, S.; Le Borgne, D.; Pannella, M.; Pope, A.; Popesso, P.

2015-07-01

Aims: We propose a new method of pushing Herschel to its faintest detection limits using universal trends in the redshift evolution of the far infrared over 24 μm colours in the well-sampled GOODS-North field. An extension to other fields with less multi-wavelength information is presented. This method is applied here to raise the contribution of individually detected Herschel sources to the cosmic infrared background (CIRB) by a factor 5 close to its peak at 250 μm and more than 3 in the 350 and 500 μm bands. Methods: We produce realistic mock Herschel images of the deep PACS and SPIRE images of the GOODS-North field from the GOODS-Herschel key program and use them to quantify the confusion noise at the position of individual sources, i.e., estimate a "local confusion noise". Two methods are used to identify sources with reliable photometric accuracy extracted using 24 μm prior positions. The clean index (CI), previously defined but validated here with simulations, which measures the presence of bright 24 μm neighbours and the photometric accuracy index (PAI) directly extracted from the mock Herschel images. Results: Both methods converge to comparable depths and fractions of the CIRB resolved into sources individually detected with Herschel. After correction for completeness, thanks to our mock Herschel images, individually detected sources make up as much as 54% and 60% of the CIRB in the PACS bands down to 1.1 mJy at 100 μm and 2.2 mJy at 160 μm and 55, 33, and 13% of the CIRB in the SPIRE bands down to 2.5, 5, and 9 mJy at 250 μm, 350 μm, and 500 μm, respectively. The latter depths improve the detection limits of Herschel by factors of 5 at 250 μm, and 3 at 350 μm and 500 μm as compared to the standard confusion limit. Interestingly, the dominant contributors to the CIRB in all Herschel bands appear to be distant siblings of the Milky Way (z ~ 0.96 for λ< 300 μm) with a stellar mass of M⋆ ~ 9 × 1010M⊙.

Good and Bad Public Prose.

ERIC Educational Resources Information Center

Cockburn, Stewart

1969-01-01

The basic requirements of all good prose are clarity, accuracy, brevity, and simplicity. Especially in public prose--in which the meaning is the crux of the article or speech--concise, vigorous English demands a minimum of adjectives, a maximum use of the active voice, nouns carefully chosen, a logical argument with no labored or obscure points,…

Assessment of nailfold capillaroscopy in systemic sclerosis by different optical magnification methods.

PubMed

Mazzotti, N G; Bredemeier, M; Brenol, C V; Xavier, R M; Cestari, T F

2014-03-01

Systemic sclerosis (SSc) is characterized by target-organ fibrosis and microvascular dysfunction, which can be assessed using nailfold capillaroscopy. Dermoscopy is a useful and easily performed method for diagnosing skin lesions. To compare conventional capillaroscopy, using the gold-standard method (conventional stereomicroscope nailfold capillaroscopy; SNFC), with polarized light noncontact dermoscopy (PNCD) and nonpolarized light contact dermoscopy (NPCD), and to evaluate their accuracy in diagnosing characteristic SSc-related alterations. The study enrolled 45 patients with SSc. Capillaroscopy images and photographs were taken with three devices, SNFC, NPCD and PNCD, and these images were randomly analysed by a blinded observer. The scleroderma pattern was found in 83% of patients. PNCD and NPCD were highly sensitive in identifying the presence of focal capillary loss (96.4% and 100%, respectively), haemorrhage (96.2% and 92%, respectively), and scleroderma (91.9%, 94.6%), and showed high specificity for haemorrhage and enlarged loops. The intra-observer kappa values for detection of the scleroderma pattern by SNFC images, NPCD and PNCD were moderate to good: (κ = 0.71 (95% CI 0.44-0.95), κ = 0.60 (95% CI 0.35-0.83) and κ = 0.60 (95% CI 0.32-0.86), respectively. Evaluation of haemorrhage presence gave high kappa values for all methods: κ = 0.77 (95% CI 0.57-0.95), κ = 0.90 (95% CI 0.76-1.00) and κ = 0.95 (95% CI 0.85-1.00), respectively. Both polarized and nonpolarized dermoscopy are reliable methods for valuation of nailfold capillaroscopy in patients with SSc. They are easy to perform, with good rates of accuracy and results that are comparable with traditional capillaroscopy. © 2013 British Association of Dermatologists.

Testing the applicability of a benthic foraminiferal-based transfer function for the reconstruction of paleowater depth changes in Rhodes (Greece) during the early Pleistocene.

PubMed

Milker, Yvonne; Weinkauf, Manuel F G; Titschack, Jürgen; Freiwald, Andre; Krüger, Stefan; Jorissen, Frans J; Schmiedl, Gerhard

2017-01-01

We present paleo-water depth reconstructions for the Pefka E section deposited on the island of Rhodes (Greece) during the early Pleistocene. For these reconstructions, a transfer function (TF) using modern benthic foraminifera surface samples from the Adriatic and Western Mediterranean Seas has been developed. The TF model gives an overall predictive accuracy of ~50 m over a water depth range of ~1200 m. Two separate TF models for shallower and deeper water depth ranges indicate a good predictive accuracy of 9 m for shallower water depths (0-200 m) but far less accuracy of 130 m for deeper water depths (200-1200 m) due to uneven sampling along the water depth gradient. To test the robustness of the TF, we randomly selected modern samples to develop random TFs, showing that the model is robust for water depths between 20 and 850 m while greater water depths are underestimated. We applied the TF to the Pefka E fossil data set. The goodness-of-fit statistics showed that most fossil samples have a poor to extremely poor fit to water depth. We interpret this as a consequence of a lack of modern analogues for the fossil samples and removed all samples with extremely poor fit. To test the robustness and significance of the reconstructions, we compared them to reconstructions from an alternative TF model based on the modern analogue technique and applied the randomization TF test. We found our estimates to be robust and significant at the 95% confidence level, but we also observed that our estimates are strongly overprinted by orbital, precession-driven changes in paleo-productivity and corrected our estimates by filtering out the precession-related component. We compared our corrected record to reconstructions based on a modified plankton/benthos (P/B) ratio, excluding infaunal species, and to stable oxygen isotope data from the same section, as well as to paleo-water depth estimates for the Lindos Bay Formation of other sediment sections of Rhodes. These comparisons indicate that our orbital-corrected reconstructions are reasonable and reflect major tectonic movements of Rhodes during the early Pleistocene.

Testing the applicability of a benthic foraminiferal-based transfer function for the reconstruction of paleowater depth changes in Rhodes (Greece) during the early Pleistocene

PubMed Central

Weinkauf, Manuel F. G.; Titschack, Jürgen; Freiwald, Andre; Krüger, Stefan; Jorissen, Frans J.; Schmiedl, Gerhard

2017-01-01

We present paleo-water depth reconstructions for the Pefka E section deposited on the island of Rhodes (Greece) during the early Pleistocene. For these reconstructions, a transfer function (TF) using modern benthic foraminifera surface samples from the Adriatic and Western Mediterranean Seas has been developed. The TF model gives an overall predictive accuracy of ~50 m over a water depth range of ~1200 m. Two separate TF models for shallower and deeper water depth ranges indicate a good predictive accuracy of 9 m for shallower water depths (0–200 m) but far less accuracy of 130 m for deeper water depths (200–1200 m) due to uneven sampling along the water depth gradient. To test the robustness of the TF, we randomly selected modern samples to develop random TFs, showing that the model is robust for water depths between 20 and 850 m while greater water depths are underestimated. We applied the TF to the Pefka E fossil data set. The goodness-of-fit statistics showed that most fossil samples have a poor to extremely poor fit to water depth. We interpret this as a consequence of a lack of modern analogues for the fossil samples and removed all samples with extremely poor fit. To test the robustness and significance of the reconstructions, we compared them to reconstructions from an alternative TF model based on the modern analogue technique and applied the randomization TF test. We found our estimates to be robust and significant at the 95% confidence level, but we also observed that our estimates are strongly overprinted by orbital, precession-driven changes in paleo-productivity and corrected our estimates by filtering out the precession-related component. We compared our corrected record to reconstructions based on a modified plankton/benthos (P/B) ratio, excluding infaunal species, and to stable oxygen isotope data from the same section, as well as to paleo-water depth estimates for the Lindos Bay Formation of other sediment sections of Rhodes. These comparisons indicate that our orbital-corrected reconstructions are reasonable and reflect major tectonic movements of Rhodes during the early Pleistocene. PMID:29166653

Pre-operative prediction of cervical nodal metastasis in papillary thyroid cancer by 99mTc-MIBI SPECT/CT; a pilot study.

PubMed

Tangjaturonrasme, Napadon; Vasavid, Pataramon; Sombuntham, Premsuda; Keelawat, Somboon

2013-06-01

Papillary thyroid cancer has a high prevalence of cervical nodal metastasis. There is no "gold standard" imaging for pre-operative diagnosis. The aim of the present study was to assess the accuracy of pre-operative 99mTc-MBI SPECT/CT in diagnosis of cervical nodal metastasis in patients with papillary thyroid cancer Fifteen patients were performed 99Tc-MlBI SPECT/CT pre-operatively. Either positive pathological report of neck dissection or positive post-treatment I-131 whole body scan with SPECT/CT of neck was concluded for definite neck metastasis. The PPV, NPV, and accuracy of 99mTc-MIBI SPECT/CT were analyzed. The PPV NPV and accuracy were 80%, 88.89%, and 85.71%, respectively. 99mTc-MIBI SPECT/CT could localize the abnormal lymph nodes groups correctly in most cases when compared with pathological results. However the authors found one false positive case with caseating granulomatous lymphadenitis and one false negative case with positive post-treatment 1-131 whole body scan with SPECT/CT of neck on cervical nodes zone II and IV CONCLUSION: 99mTc-MIBI SPECT/CTseem promising for pre-operative staging of cervical nodal involvement in patients with papillary thyroid cancer without the need of using iodinated contrast that may complicate subsequence 1-131 treatment. However, false positive result in granulomatous inflammatory nodes should be aware of especially in endemic areas. 99mTc-MIBI SPECT/CT scan shows a good result when compared with previous study of CT or MRI imaging. The comparative study between different imaging modality and the extension of neck dissection according to MIBI result seems interesting.

A comparative analysis of noncontrast flow-spoiled versus contrast-enhanced magnetic resonance angiography for evaluation of peripheral arterial disease.

PubMed

Kassamali, Rahil Hussein; Hoey, Edward T D; Ganeshan, Arul; Littlehales, Tracey

2013-01-01

This feasibility study aimed to obtain initial data to assess the performance of a novel noncontrast spoiled magnetic resonance (MR) angiography technique (fresh-blood imaging [FBI]) compared to gadolinium-enhanced MR (Gd-MR) angiography for evaluation of the aorto-iliac and lower extremity arteries. Thirteen patients with suspected lower extremity arterial disease that had undergone Gd-MR angiography and FBI at the same session were randomly included in the study. FBI was performed using an ECG-gated ow-spoiled T2-weighted half-Fourier fast spin-echo sequence. For analysis, the aortoiliac and lower limb arteries were divided into 18 anatomical segments. Two blinded readers individually graded image quality of FBI and also assessed the presence and severity of any stenotic lesions. A similar analysis was performed for the Gd-MR angiography images. A total of 385 arterial segments were analyzed; 34 segments were excluded due to degraded image quality (1.3% of Gd- MR vs. 8% of FBI-MR angiography images). FBI-MR angiography had comparable accuracy to Gd-MR angiography for assessment of the above knee vessels with high kappa statistics (large arteries, 0.91; small arteries, 0.86) and high sensitivity (large arteries, 98.1%; small arteries, 88.6%) and specificity (large arteries, 97.2%; small arteries, 97.6%) using Gd-MR angiography as the gold standard. Initial results show good agreement between FBI-MR angiography and Gd-MR angiography in the diagnosis of peripheral arterial disease, making FBI a potential alternative in patients with renal impairment. FBI showed highest accuracy in the above knee vessels. Technological refinements are required to improve accuracy for assessing the calf and pedal vessels.

Validation of Contact-Free Sleep Monitoring Device with Comparison to Polysomnography.

PubMed

Tal, Asher; Shinar, Zvika; Shaki, David; Codish, Shlomi; Goldbart, Aviv

2017-03-15

To validate a contact-free system designed to achieve maximal comfort during long-term sleep monitoring, together with high monitoring accuracy. We used a contact-free monitoring system (EarlySense, Ltd., Israel), comprising an under-the-mattress piezoelectric sensor and a smartphone application, to collect vital signs and analyze sleep. Heart rate (HR), respiratory rate (RR), body movement, and calculated sleep-related parameters from the EarlySense (ES) sensor were compared to data simultaneously generated by the gold standard, polysomnography (PSG). Subjects in the sleep laboratory underwent overnight technician-attended full PSG, whereas subjects at home were recorded for 1 to 3 nights with portable partial PSG devices. Data were compared epoch by epoch. A total of 63 subjects (85 nights) were recorded under a variety of sleep conditions. Compared to PSG, the contact-free system showed similar values for average total sleep time (TST), % wake, % rapid eye movement, and % non-rapid eye movement sleep, with 96.1% and 93.3% accuracy of continuous measurement of HR and RR, respectively. We found a linear correlation between TST measured by the sensor and TST determined by PSG, with a coefficient of 0.98 (R = 0.87). Epoch-by-epoch comparison with PSG in the sleep laboratory setting revealed that the system showed sleep detection sensitivity, specificity, and accuracy of 92.5%, 80.4%, and 90.5%, respectively. TST estimates with the contact-free sleep monitoring system were closely correlated with the gold-standard reference. This system shows good sleep staging capability with improved performance over accelerometer-based apps, and collects additional physiological information on heart rate and respiratory rate. © 2017 American Academy of Sleep Medicine

Diagnostic value of 3.0T (1)H MRS with choline-containing compounds ratio (∆CCC) in primary malignant hepatic tumors.

PubMed

Zhang, Li; Zhao, Xinming; Ouyang, Han; Wang, Shuang; Zhou, Chunwu

2016-08-22

The purpose of this study was to investigate the diagnostic value of 3.0-T (1)H magnetic resonance spectroscopy ((1)H MRS) in primary malignant hepatic tumors and to compare the effects of (1)H MRS on the diagnostic accuracy of liver-occupying lesions between junior and experienced radiologists. This study included 50 healthy volunteers and 40 consecutive patients (50 lesions). Informed consent was obtained from each subject. Images were obtained on clinical whole-body 3.0-T MR system. Point -Resolved Spectroscopy was used to obtain the spectroscopy image. All conventional images were reviewed blindly by junior radiologist and experienced radiologist, respectively. The choline-containing compounds peak area (CCC-A) was measured with SAGE software, and the choline-containing compound ratio (∆CCC) was calculated. The efficacy of CCC-A and ∆CCC in the diagnosis of primary malignant hepatic tumors was determined by plotting receiver operating characteristic (ROC) curves. We also compared the effects of MRS on the diagnostic accuracy of liver-occupying lesions with junior and experienced radiologist. A significant increase in mean CCC-A was observed in malignant tumors compared with benign tumors. The ROC curve showed ∆CCC had a high discriminatory ability in diagnosing primary malignant hepatic tumors with a sensitivity and specificity of 94.3 and 93.3 %, respectively. The ∆CCC area under the curve (AUC) was 0.97 that was larger than that of both junior and experienced radiologist, while the significantly statistical difference was only obtained between ∆CCC and junior radiologist (P = 0.01). (1)H MRS with ∆CCC demonstrates good efficacy in diagnosing primary malignant hepatic tumors. The technique improves the accuracy of diagnosing liver-occupying lesions, particularly for junior radiologists.

Investigation of the Aerodynamic Performance of a DG808s UAS in Propeller Slipstream Using Computational Fluid Dynamics

NASA Astrophysics Data System (ADS)

Chandra, Yatish

Unmanned Aerial Systems (UASs) are relatively affordable and immediately available compared to commercial aircraft. Hence, their aerodynamics and design accuracies are often based on extrapolating from design standards and procedures widely used in the aerospace industry for commercial aircraft with most often, acceptable results. Engineering level software such as Advanced Aircraft Analysis (AAA) use general aviation aircraft data and later extrapolate them onto UASs for aerodynamic and flight dynamics modeling but are limited by their platform repository and relatively high Reynolds number evaluations. UASs however, are aircraft which fly at comparatively low speeds and low Reynolds number with close proximities between the components wherein such standards may not hold good. This thesis focuses on evaluating the accuracy and impact of such industry standards on the aerodynamics and flight dynamics of UASs. A DG808s UAS is chosen for the study which was previously modeled using the AAA software at The University of Kansas by the Flight Systems Team. Using the STAR-CCM+ code, performance data were compared and assessed with AAA. Aerodynamic simulations were carried out for two different configurations viz., aircraft with and without propeller slipstream effects. Data obtained for the non-powered simulations were found to be in good agreement with the AAA model. For the powered flight however, discrepancies between the AAA model and CFD data were observed with large values for the vertical tail side-force coefficient. A comparison with the system identification data from the flight tests was made to confirm and validate this vertical tail behavior with the help of rudder deflection inputs. A relationship between the propeller RPM and the aerodynamic model was established by simulating two different propeller speeds. Based on the STAR-CCM+ data and the resulting comparisons with AAA, updates necessary to the UAS aerodynamic and flight dynamics models currently used in the industry were discussed and concluded with a stress on dependency on higher fidelity methods such as Computational Fluid Dynamics.

Snow Climatology of Arctic Sea Ice: Comparison of Reanalysis and Climate Model Data with In Situ Measurements

NASA Astrophysics Data System (ADS)

Chevooruvalappil Chandran, B.; Pittana, M.; Haas, C.

2015-12-01

Snow on sea ice is a critical and complex factor influencing sea ice processes. Deep snow with a high albedo and low thermal conductivity inhibits ice growth in winter and minimizes ice loss in summer. Very shallow or absent snow promotes ice growth in winter and ice loss in summer. The timing of snow ablation critically impacts summer sea ice mass balance. Here we assess the accuracy of various snow on sea ice data products from reanalysis and modeling comparing them with in situ measurements. The latter are based on the Warren et al. (1999) monthly climatology derived from snow ruler measurements between 1954-1991, and on daily snow depth retrievals from few drifting ice mass balance buoys (IMB) with sufficiently long observations spanning the summer season. These were compared with snow depth data from the National Center for Environmental Prediction Department of Energy Reanalysis 2 (NCEP), the Community Climate System Model 4 (CCSM4), and the Canadian Earth System Model 2 (CanESM2). Results are quite variable in different years and regions. However, there is often good agreement between CanESM2 and IMB snow depth during the winter accumulation and spring melt periods. Regional analyses show that over the western Arctic covered primarily with multiyear ice NCEP snow depths are in good agreement with the Warren climatology while CCSM4 overestimates snow depth. However, in the Eastern Arctic which is dominated by first-year ice the opposite behavior is observed. Compared to the Warren climatology CanESM2 underestimates snow depth in all regions. Differences between different snow depth products are as large as 10 to 20 cm, with large consequences for the sea ice mass balance. However, it is also very difficult to evaluate the accuracy of reanalysis and model snow depths due to a lack of extensive, continuous in situ measurements.

Comparison of automated volumetry of the hippocampus using NeuroQuant® and visual assessment of the medial temporal lobe in Alzheimer's disease.

PubMed

Persson, Karin; Barca, Maria Lage; Cavallin, Lena; Brækhus, Anne; Knapskog, Anne-Brita; Selbæk, Geir; Engedal, Knut

2017-01-01

Background Different clinically feasible methods for evaluation of medial temporal lobe atrophy exists and are useful in diagnostic work-up of Alzheimer's disease (AD). Purpose To compare the diagnostic properties of two clinically available magnetic resonance imaging (MRI)-based methods-an automated volumetric software, NeuroQuant® (NQ) (evaluation of hippocampus volume) and the Scheltens scale (visual evaluation of medial temporal lobe atrophy [MTA])-in patients with AD dementia, and subjective and mild cognitive impairment (non-dementia). Material and Methods MRIs from 56 patients (31 AD, 25 non-dementia) were assessed with both methods. Correlations between the methods were calculated and receiver operating curve (ROC) analyses that yield area under the curve (AUC) statistics were conducted. Results High correlations were found between the two MRI assessments for the total hippocampal volume measured with NQ and mean MTA score (-0.753, P < 0.001), for the right (-0.767, P < 0.001), and for the left (-0.675, P < 0.001) sides. The NQ total measure yielded somewhat higher AUC (0.88, "good") compared to the MTA mean measure (0.80, "good") in the comparison of patients with AD and non-dementia, but the accuracy was in favor of the MTA scale. Conclusion The two methods correlated highly and both methods reached equally "good" power.

Narrative Skills, Gender, Culture, and Children's Long-Term Memory Accuracy of a Staged Event

ERIC Educational Resources Information Center

Klemfuss, J. Zoe; Wang, Qi

2017-01-01

This study examined the extent to which school-aged children's general narrative skills provide cognitive benefits for accurate remembering or enable good storytelling that undermines memory accuracy. European American and Chinese American 6-year-old boys and girls (N = 114) experienced a staged event in the laboratory and were asked to tell a…

Is computed tomography an accurate and reliable method for measuring total knee arthroplasty component rotation?

PubMed

Figueroa, José; Guarachi, Juan Pablo; Matas, José; Arnander, Magnus; Orrego, Mario

2016-04-01

Computed tomography (CT) is widely used to assess component rotation in patients with poor results after total knee arthroplasty (TKA). The purpose of this study was to simultaneously determine the accuracy and reliability of CT in measuring TKA component rotation. TKA components were implanted in dry-bone models and assigned to two groups. The first group (n = 7) had variable femoral component rotations, and the second group (n = 6) had variable tibial tray rotations. CT images were then used to assess component rotation. Accuracy of CT rotational assessment was determined by mean difference, in degrees, between implanted component rotation and CT-measured rotation. Intraclass correlation coefficient (ICC) was applied to determine intra-observer and inter-observer reliability. Femoral component accuracy showed a mean difference of 2.5° and the tibial tray a mean difference of 3.2°. There was good intra- and inter-observer reliability for both components, with a femoral ICC of 0.8 and 0.76, and tibial ICC of 0.68 and 0.65, respectively. CT rotational assessment accuracy can differ from true component rotation by approximately 3° for each component. It does, however, have good inter- and intra-observer reliability.

Effects of pH, lactate, hematocrit and potassium level on the accuracy of continuous glucose monitoring (CGM) in pediatric intensive care unit.

PubMed

Marics, Gábor; Koncz, Levente; Eitler, Katalin; Vatai, Barbara; Szénási, Boglárka; Zakariás, David; Mikos, Borbála; Körner, Anna; Tóth-Heyn, Péter

2015-03-19

Continuous glucose monitoring (CGM) originally was developed for diabetic patients and it may be a useful tool for monitoring glucose changes in pediatric intensive care unit (PICU). Its use is, however, limited by the lack of sufficient data on its reliability at insufficient peripheral perfusion. We aimed to correlate the accuracy of CGM with laboratory markers relevant to disturbed tissue perfusion. In 38 pediatric patients (age range, 0-18 years) requiring intensive care we tested the effect of pH, lactate, hematocrit and serum potassium on the difference between CGM and meter glucose measurements. Guardian® (Medtronic®) CGM results were compared to GEM 3000 (Instrumentation laboratory®) and point-of-care measurements. The clinical accuracy of CGM was evaluated by Clarke Error Grid -, Bland-Altman analysis and Pearson's correlation. We used Friedman test for statistical analysis (statistical significance was established as a p < 0.05). CGM values exhibited a considerable variability without any correlation with the examined laboratory parameters. Clarke, Bland-Altman analysis and Pearson's correlation coefficient demonstrated a good clinical accuracy of CGM (zone A and B = 96%; the mean difference between reference and CGM glucose was 1,3 mg/dL, 48 from the 780 calibration pairs overrunning the 2 standard deviation; Pearson's correlation coefficient: 0.83). The accuracy of CGM measurements is independent of laboratory parameters relevant to tissue hypoperfusion. CGM may prove a reliable tool for continuous monitoring of glucose changes in PICUs, not much influenced by tissue perfusion, but still not appropriate for being the base for clinical decisions.

Genotyping by sequencing for genomic prediction in a soybean breeding population.

PubMed

Jarquín, Diego; Kocak, Kyle; Posadas, Luis; Hyma, Katie; Jedlicka, Joseph; Graef, George; Lorenz, Aaron

2014-08-29

Advances in genotyping technology, such as genotyping by sequencing (GBS), are making genomic prediction more attractive to reduce breeding cycle times and costs associated with phenotyping. Genomic prediction and selection has been studied in several crop species, but no reports exist in soybean. The objectives of this study were (i) evaluate prospects for genomic selection using GBS in a typical soybean breeding program and (ii) evaluate the effect of GBS marker selection and imputation on genomic prediction accuracy. To achieve these objectives, a set of soybean lines sampled from the University of Nebraska Soybean Breeding Program were genotyped using GBS and evaluated for yield and other agronomic traits at multiple Nebraska locations. Genotyping by sequencing scored 16,502 single nucleotide polymorphisms (SNPs) with minor-allele frequency (MAF) > 0.05 and percentage of missing values ≤ 5% on 301 elite soybean breeding lines. When SNPs with up to 80% missing values were included, 52,349 SNPs were scored. Prediction accuracy for grain yield, assessed using cross validation, was estimated to be 0.64, indicating good potential for using genomic selection for grain yield in soybean. Filtering SNPs based on missing data percentage had little to no effect on prediction accuracy, especially when random forest imputation was used to impute missing values. The highest accuracies were observed when random forest imputation was used on all SNPs, but differences were not significant. A standard additive G-BLUP model was robust; modeling additive-by-additive epistasis did not provide any improvement in prediction accuracy. The effect of training population size on accuracy began to plateau around 100, but accuracy steadily climbed until the largest possible size was used in this analysis. Including only SNPs with MAF > 0.30 provided higher accuracies when training populations were smaller. Using GBS for genomic prediction in soybean holds good potential to expedite genetic gain. Our results suggest that standard additive G-BLUP models can be used on unfiltered, imputed GBS data without loss in accuracy.

Optical properties of reduced graphene oxide and CuFe2O4 composites in the IR region

NASA Astrophysics Data System (ADS)

Ma, De-yue; Li, Xiao-xia; Guo, Yu-xiang; Zeng, Yu-run

2018-01-01

The complex refractive index of reduced graphene oxide and CuFe2O4 composites prepared by hydrothermal method was calculated using infrared Micro-reflective spectra and K-K relation, and the calculation errors were analyzed according to its IR transmission and spectral reflectivity calculated by Fresnel formula. And then normal emissivity of the composite in IR atmospheric window was calculated by means of Fresnel formula and modified refraction angle formula. The calculation accuracy was verified by comparing measured normal total emissivity with the calculated one. The results show that complex refractive index and normal emissivity calculated by the formulas have a high accuracy. It has been found that the composite has a good absorption and radiation characteristics in IR atmospheric window and a strong scattering ability in middle IR region by analyzing its extinction, absorption and radiation properties in IR region. Therefore, it may be used as IR absorption, extinction and radiation materials in some special fields.

Variational approach to probabilistic finite elements

NASA Technical Reports Server (NTRS)

Belytschko, T.; Liu, W. K.; Mani, A.; Besterfield, G.

1991-01-01

Probabilistic finite element methods (PFEM), synthesizing the power of finite element methods with second-moment techniques, are formulated for various classes of problems in structural and solid mechanics. Time-invariant random materials, geometric properties and loads are incorporated in terms of their fundamental statistics viz. second-moments. Analogous to the discretization of the displacement field in finite element methods, the random fields are also discretized. Preserving the conceptual simplicity, the response moments are calculated with minimal computations. By incorporating certain computational techniques, these methods are shown to be capable of handling large systems with many sources of uncertainties. By construction, these methods are applicable when the scale of randomness is not very large and when the probabilistic density functions have decaying tails. The accuracy and efficiency of these methods, along with their limitations, are demonstrated by various applications. Results obtained are compared with those of Monte Carlo simulation and it is shown that good accuracy can be obtained for both linear and nonlinear problems. The methods are amenable to implementation in deterministic FEM based computer codes.

Variational approach to probabilistic finite elements

NASA Astrophysics Data System (ADS)

Belytschko, T.; Liu, W. K.; Mani, A.; Besterfield, G.

1991-08-01

Probabilistic finite element methods (PFEM), synthesizing the power of finite element methods with second-moment techniques, are formulated for various classes of problems in structural and solid mechanics. Time-invariant random materials, geometric properties and loads are incorporated in terms of their fundamental statistics viz. second-moments. Analogous to the discretization of the displacement field in finite element methods, the random fields are also discretized. Preserving the conceptual simplicity, the response moments are calculated with minimal computations. By incorporating certain computational techniques, these methods are shown to be capable of handling large systems with many sources of uncertainties. By construction, these methods are applicable when the scale of randomness is not very large and when the probabilistic density functions have decaying tails. The accuracy and efficiency of these methods, along with their limitations, are demonstrated by various applications. Results obtained are compared with those of Monte Carlo simulation and it is shown that good accuracy can be obtained for both linear and nonlinear problems. The methods are amenable to implementation in deterministic FEM based computer codes.

Variational approach to probabilistic finite elements

NASA Technical Reports Server (NTRS)

Belytschko, T.; Liu, W. K.; Mani, A.; Besterfield, G.

1987-01-01

Probabilistic finite element method (PFEM), synthesizing the power of finite element methods with second-moment techniques, are formulated for various classes of problems in structural and solid mechanics. Time-invariant random materials, geometric properties, and loads are incorporated in terms of their fundamental statistics viz. second-moments. Analogous to the discretization of the displacement field in finite element methods, the random fields are also discretized. Preserving the conceptual simplicity, the response moments are calculated with minimal computations. By incorporating certain computational techniques, these methods are shown to be capable of handling large systems with many sources of uncertainties. By construction, these methods are applicable when the scale of randomness is not very large and when the probabilistic density functions have decaying tails. The accuracy and efficiency of these methods, along with their limitations, are demonstrated by various applications. Results obtained are compared with those of Monte Carlo simulation and it is shown that good accuracy can be obtained for both linear and nonlinear problems. The methods are amenable to implementation in deterministic FEM based computer codes.

An Investigation into the Application of Generalized Differential Quadrature Method to Bending Analysis of Composite Sandwich Plates

NASA Astrophysics Data System (ADS)

Ghassemi, Aazam; Yazdani, Mostafa; Hedayati, Mohamad

2017-12-01

In this work, based on the First Order Shear Deformation Theory (FSDT), an attempt is made to explore the applicability and accuracy of the Generalized Differential Quadrature Method (GDQM) for bending analysis of composite sandwich plates under static loading. Comparative studies of the bending behavior of composite sandwich plates are made between two types of boundary conditions for different cases. The effects of fiber orientation, ratio of thickness to length of the plate, the ratio of thickness of core to thickness of the face sheet are studied on the transverse displacement and moment resultants. As shown in this study, the role of the core thickness in deformation of these plates can be reversed by the stiffness of the core in comparison with sheets. The obtained graphs give very good results due to optimum design of sandwich plates. In Comparison with existing solutions, fast convergent rates and high accuracy results can be achieved by the GDQ method.

Development of a data-processing method based on Bayesian k-means clustering to discriminate aneugens and clastogens in a high-content micronucleus assay.

PubMed

Huang, Z H; Li, N; Rao, K F; Liu, C T; Huang, Y; Ma, M; Wang, Z J

2018-03-01

Genotoxicants can be identified as aneugens and clastogens through a micronucleus (MN) assay. The current high-content screening-based MN assays usually discriminate an aneugen from a clastogen based on only one parameter, such as the MN size, intensity, or morphology, which yields low accuracies (70-84%) because each of these parameters may contribute to the results. Therefore, the development of an algorithm that can synthesize high-dimensionality data to attain comparative results is important. To improve the automation and accuracy of detection using the current parameter-based mode of action (MoA), the MN MoA signatures of 20 chemicals were systematically recruited in this study to develop an algorithm. The results of the algorithm showed very good agreement (93.58%) between the prediction and reality, indicating that the proposed algorithm is a validated analytical platform for the rapid and objective acquisition of genotoxic MoA messages.

[Research on direct forming of comminuted fracture surgery orienting model by selective laser melting].

PubMed

He, Xingrong; Yang, Yongqiang; Wu, Weihui; Wang, Di; Ding, Huanwen; Huang, Weihong

2010-06-01

In order to simplify the distal femoral comminuted fracture surgery and improve the accuracy of the parts to be reset, a kind of surgery orienting model for the surgery operation was designed according to the scanning data of computer tomography and the three-dimensional reconstruction image. With the use of DiMetal-280 selective laser melting rapid prototyping system, the surgery orienting model of 316L stainless steel was made through orthogonal experiment for processing parameter optimization. The technology of direct manufacturing of surgery orienting model by selective laser melting was noted to have obvious superiority with high speed, precise profile and good accuracy in size when compared with the conventional one. The model was applied in a real surgical operation for thighbone replacement; it worked well. The successful development of the model provides a new method for the automatic manufacture of customized surgery model, thus building a foundation for more clinical applications in the future.

Forecasting the onset of an allergic risk to poaceae in Nancy and Strasbourg (France) with different methods.

PubMed

Cassagne, E; Caillaud, P D; Besancenot, J P; Thibaudon, M

2007-10-01

Pollen of Poaceae is among the most allergenic pollen in Europe with pollen of birch. It is therefore useful to elaborate models to help pollen allergy sufferers. The objective of this study was to construct forecast models that could predict the first day characterized by a certain level of allergic risk called here the Starting Date of the Allergic Risk (SDAR). Models result from four forecast methods (three summing and one multiple regression analysis) used in the literature. They were applied on Nancy and Strasbourg from 1988 to 2005 and were tested on 2006. Mean Absolute Error and Actual forecast ability test are the parameters used to choose best models, assess and compare their accuracy. It was found, on the whole, that all the models presented a good forecast accuracy which was equivalent. They were all reliable and were used in order to forecast the SDAR in 2006 with contrasting results in forecasting precision.

Quantitative analysis of γ-oryzanol content in cold pressed rice bran oil by TLC-image analysis method.

PubMed

Sakunpak, Apirak; Suksaeree, Jirapornchai; Monton, Chaowalit; Pathompak, Pathamaporn; Kraisintu, Krisana

2014-02-01

To develop and validate an image analysis method for quantitative analysis of γ-oryzanol in cold pressed rice bran oil. TLC-densitometric and TLC-image analysis methods were developed, validated, and used for quantitative analysis of γ-oryzanol in cold pressed rice bran oil. The results obtained by these two different quantification methods were compared by paired t-test. Both assays provided good linearity, accuracy, reproducibility and selectivity for determination of γ-oryzanol. The TLC-densitometric and TLC-image analysis methods provided a similar reproducibility, accuracy and selectivity for the quantitative determination of γ-oryzanol in cold pressed rice bran oil. A statistical comparison of the quantitative determinations of γ-oryzanol in samples did not show any statistically significant difference between TLC-densitometric and TLC-image analysis methods. As both methods were found to be equal, they therefore can be used for the determination of γ-oryzanol in cold pressed rice bran oil.

Quantitative analysis of γ-oryzanol content in cold pressed rice bran oil by TLC-image analysis method

PubMed Central

Sakunpak, Apirak; Suksaeree, Jirapornchai; Monton, Chaowalit; Pathompak, Pathamaporn; Kraisintu, Krisana

2014-01-01

Objective To develop and validate an image analysis method for quantitative analysis of γ-oryzanol in cold pressed rice bran oil. Methods TLC-densitometric and TLC-image analysis methods were developed, validated, and used for quantitative analysis of γ-oryzanol in cold pressed rice bran oil. The results obtained by these two different quantification methods were compared by paired t-test. Results Both assays provided good linearity, accuracy, reproducibility and selectivity for determination of γ-oryzanol. Conclusions The TLC-densitometric and TLC-image analysis methods provided a similar reproducibility, accuracy and selectivity for the quantitative determination of γ-oryzanol in cold pressed rice bran oil. A statistical comparison of the quantitative determinations of γ-oryzanol in samples did not show any statistically significant difference between TLC-densitometric and TLC-image analysis methods. As both methods were found to be equal, they therefore can be used for the determination of γ-oryzanol in cold pressed rice bran oil. PMID:25182282

Characterisation of the n-colour printing process using the spot colour overprint model.

PubMed

Deshpande, Kiran; Green, Phil; Pointer, Michael R

2014-12-29

This paper is aimed at reproducing the solid spot colours using the n-colour separation. A simplified numerical method, called as the spot colour overprint (SCOP) model, was used for characterising the n-colour printing process. This model was originally developed for estimating the spot colour overprints. It was extended to be used as a generic forward characterisation model for the n-colour printing process. The inverse printer model based on the look-up table was implemented to obtain the colour separation for n-colour printing process. Finally the real-world spot colours were reproduced using 7-colour separation on lithographic offset printing process. The colours printed with 7 inks were compared against the original spot colours to evaluate the accuracy. The results show good accuracy with the mean CIEDE2000 value between the target colours and the printed colours of 2.06. The proposed method can be used successfully to reproduce the spot colours, which can potentially save significant time and cost in the printing and packaging industry.

Validation of Accelerometer Cut-Points in Children With Cerebral Palsy Aged 4 to 5 Years.

PubMed

Keawutan, Piyapa; Bell, Kristie L; Oftedal, Stina; Davies, Peter S W; Boyd, Roslyn N

2016-01-01

To derive and validate triaxial accelerometer cut-points in children with cerebral palsy (CP) and compare these with previously established cut-points in children with typical development. Eighty-four children with CP aged 4 to 5 years wore the ActiGraph during a play-based gross motor function measure assessment that was video-taped for direct observation. Receiver operating characteristic and Bland-Altman plots were used for analyses. The ActiGraph had good classification accuracy in Gross Motor Function Classification System (GMFCS) levels III and V and fair classification accuracy in GMFCS levels I, II, and IV. These results support the use of the previously established cut-points for sedentary time of 820 counts per minute in children with CP aged 4 to 5 years across all functional abilities. The cut-point provides an objective measure of sedentary and active time in children with CP. The cut-point is applicable to group data but not for individual children.

An assessment of the accuracy of orthotropic photoelasticity

NASA Technical Reports Server (NTRS)

Hyer, M. W.; Liu, D. H.

1984-01-01

The accuracy of orthotropic photoelasticity was studied. The study consisted of both theoretical and experimental phases. In the theoretical phase a stress-optic law was developed. The stress-optic law included the effects of residual birefringence in the relation between applied stress and the material's optical response. The experimental phase had several portions. First, it was shown that four-point bending tests and the concept of an optical neutral axis could be conveniently used to calibrate the stress-optic behavior of the material. Second, the actual optical response of an orthotropic disk in diametral compression was compared with theoretical predictions. Third, the stresses in the disk were determined from the observed optical response, the stress-optic law, and a finite-difference form of the plane stress equilibrium equations. It was concluded that orthotropic photoelasticity is not as accurate as isotropic photoelasticity. This is believed to be due to the lack of good fringe resolution and the low sensitivity of most orthotropic photoelastic materials.

Measuring a diffusion coefficient by single-particle tracking: statistical analysis of experimental mean squared displacement curves.

PubMed

Ernst, Dominique; Köhler, Jürgen

2013-01-21

We provide experimental results on the accuracy of diffusion coefficients obtained by a mean squared displacement (MSD) analysis of single-particle trajectories. We have recorded very long trajectories comprising more than 1.5 × 10(5) data points and decomposed these long trajectories into shorter segments providing us with ensembles of trajectories of variable lengths. This enabled a statistical analysis of the resulting MSD curves as a function of the lengths of the segments. We find that the relative error of the diffusion coefficient can be minimized by taking an optimum number of points into account for fitting the MSD curves, and that this optimum does not depend on the segment length. Yet, the magnitude of the relative error for the diffusion coefficient does, and achieving an accuracy in the order of 10% requires the recording of trajectories with about 1000 data points. Finally, we compare our results with theoretical predictions and find very good qualitative and quantitative agreement between experiment and theory.

A modified potential for HO2 with spectroscopic accuracy

NASA Astrophysics Data System (ADS)

Brandão, João; Rio, Carolina M. A.; Tennyson, Jonathan

2009-04-01

Seven ground state potential energy surfaces for the hydroperoxyl radical are compared. The potentials were determined from either high-quality ab initio calculations, fits to spectroscopic data, or a combination of the two approaches. Vibration-rotation calculations are performed on each potential and the results compared with experiment. None of the available potentials is entirely satisfactory although the best spectroscopic results are obtained using the Morse oscillator rigid bender internal dynamics potential [Bunker et al., J. Mol. Spectrosc. 155, 44 (1992)]. We present modifications of the double many-body expansion IV potential of Pastrana et al. [J. Chem. Phys. 94, 8093 (1990)]. These new potentials reproduce the observed vibrational levels and observed vibrational levels and rotational constants, respectively, while preserving the good global properties of the original potential.

Tight-binding study of stacking fault energies and the Rice criterion of ductility in the fcc metals

NASA Astrophysics Data System (ADS)

Mehl, Michael J.; Papaconstantopoulos, Dimitrios A.; Kioussis, Nicholas; Herbranson, M.

2000-02-01

We have used the Naval Research Laboratory (NRL) tight-binding (TB) method to calculate the generalized stacking fault energy and the Rice ductility criterion in the fcc metals Al, Cu, Rh, Pd, Ag, Ir, Pt, Au, and Pb. The method works well for all classes of metals, i.e., simple metals, noble metals, and transition metals. We compared our results with full potential linear-muffin-tin orbital and embedded atom method (EAM) calculations, as well as experiment, and found good agreement. This is impressive, since the NRL-TB approach only fits to first-principles full-potential linearized augmented plane-wave equations of state and band structures for cubic systems. Comparable accuracy with EAM potentials can be achieved only by fitting to the stacking fault energy.

Measurement system with high accuracy for laser beam quality.

PubMed

Ke, Yi; Zeng, Ciling; Xie, Peiyuan; Jiang, Qingshan; Liang, Ke; Yang, Zhenyu; Zhao, Ming

2015-05-20

Presently, most of the laser beam quality measurement system collimates the optical path manually with low efficiency and low repeatability. To solve these problems, this paper proposed a new collimated method to improve the reliability and accuracy of the measurement results. The system accuracy controlled the position of the mirror to change laser beam propagation direction, which can realize the beam perpendicularly incident to the photosurface of camera. The experiment results show that the proposed system has good repeatability and the measuring deviation of M² factor is less than 0.6%.

Differential Effects of Context and Feedback on Orthographic Learning: How Good Is Good Enough?

ERIC Educational Resources Information Center

Martin-Chang, Sandra; Ouellette, Gene; Bond, Linda

2017-01-01

In this study, students in Grade 2 read different sets of words under 4 experimental training conditions (context/feedback, isolation/feedback, context/no-feedback, isolation/no-feedback). Training took place over 10 trials, followed by a spelling test and a delayed reading posttest. Reading in context boosted reading accuracy initially; in…

13C labeling analysis of sugars by high resolution-mass spectrometry for metabolic flux analysis.

PubMed

Acket, Sébastien; Degournay, Anthony; Merlier, Franck; Thomasset, Brigitte

2017-06-15

Metabolic flux analysis is particularly complex in plant cells because of highly compartmented metabolism. Analysis of free sugars is interesting because it provides data to define fluxes around hexose, pentose, and triose phosphate pools in different compartment. In this work, we present a method to analyze the isotopomer distribution of free sugars labeled with carbon 13 using a liquid chromatography-high resolution mass spectrometry, without derivatized procedure, adapted for Metabolic flux analysis. Our results showed a good sensitivity, reproducibility and better accuracy to determine isotopic enrichments of free sugars compared to our previous methods [5, 6]. Copyright © 2017 Elsevier Inc. All rights reserved.

Prediction of high frequency core loss for electrical steel using the data provided by manufacturer

NASA Astrophysics Data System (ADS)

Roy, Rakesh; Dalal, Ankit; Kumar, Praveen

2016-07-01

This paper describes a technique to determine the core loss data, at high frequencies, using the loss data provided by the lamination manufacturer. Steinmetz equation is used in this proposed method to determine core loss at high frequency. This Steinmetz equation consists of static hysteresis and eddy current loss. The presented technique considers the coefficients of Steinmetz equation as variable with frequency and peak magnetic flux density. The high frequency core loss data, predicted using this model is compared with the catalogue data given by manufacturer and very good accuracy has been obtained for a wide range of frequency.

Performance of Geant4 in simulating semiconductor particle detector response in the energy range below 1 MeV

NASA Astrophysics Data System (ADS)

Soti, G.; Wauters, F.; Breitenfeldt, M.; Finlay, P.; Kraev, I. S.; Knecht, A.; Porobić, T.; Zákoucký, D.; Severijns, N.

2013-11-01

Geant4 simulations play a crucial role in the analysis and interpretation of experiments providing low energy precision tests of the Standard Model. This paper focuses on the accuracy of the description of the electron processes in the energy range between 100 and 1000 keV. The effect of the different simulation parameters and multiple scattering models on the backscattering coefficients is investigated. Simulations of the response of HPGe and passivated implanted planar Si detectors to β particles are compared to experimental results. An overall good agreement is found between Geant4 simulations and experimental data.

Determination of Oversulphated Chondroitin Sulphate and Dermatan Sulphate in unfractionated heparin by (1)H-NMR - Collaborative study for quantification and analytical determination of LoD.

PubMed

McEwen, I; Mulloy, B; Hellwig, E; Kozerski, L; Beyer, T; Holzgrabe, U; Wanko, R; Spieser, J-M; Rodomonte, A

2008-12-01

Oversulphated Chondroitin Sulphate (OSCS) and Dermatan Sulphate (DS) in unfractionated heparins can be identified by nuclear magnetic resonance spectrometry (NMR). The limit of detection (LoD) of OSCS is 0.1% relative to the heparin content. This LoD is obtained at a signal-to-noise ratio (S/N) of 2000:1 of the heparin methyl signal. Quantification is best obtained by comparing peak heights of the OSCS and heparin methyl signals. Reproducibility of less than 10% relative standard deviation (RSD) has been obtained. The accuracy of quantification was good.

Improved Frame Mode Selection for AMR-WB+ Based on Decision Tree

NASA Astrophysics Data System (ADS)

Kim, Jong Kyu; Kim, Nam Soo

In this letter, we propose a coding mode selection method for the AMR-WB+ audio coder based on a decision tree. In order to reduce computation while maintaining good performance, decision tree classifier is adopted with the closed loop mode selection results as the target classification labels. The size of the decision tree is controlled by pruning, so the proposed method does not increase the memory requirement significantly. Through an evaluation test on a database covering both speech and music materials, the proposed method is found to achieve a much better mode selection accuracy compared with the open loop mode selection module in the AMR-WB+.

The application of mixed recommendation algorithm with user clustering in the microblog advertisements promotion

NASA Astrophysics Data System (ADS)

Gong, Lina; Xu, Tao; Zhang, Wei; Li, Xuhong; Wang, Xia; Pan, Wenwen

2017-03-01

The traditional microblog recommendation algorithm has the problems of low efficiency and modest effect in the era of big data. In the aim of solving these issues, this paper proposed a mixed recommendation algorithm with user clustering. This paper first introduced the situation of microblog marketing industry. Then, this paper elaborates the user interest modeling process and detailed advertisement recommendation methods. Finally, this paper compared the mixed recommendation algorithm with the traditional classification algorithm and mixed recommendation algorithm without user clustering. The results show that the mixed recommendation algorithm with user clustering has good accuracy and recall rate in the microblog advertisements promotion.

Optical Hilbert transform using fiber Bragg gratings

NASA Astrophysics Data System (ADS)

Ge, Jing; Wang, Chinhua; Zhu, Xiaojun

2010-11-01

In this paper, we demonstrate that a simple and practical phase-shifted fiber Bragg grating (PSFBG) operated in reflection can provide the required spectral response for implementing an all-optical Hilbert transformer (HT), including both integer and fractional orders. The PSFBG consists of two concatenated identical uniform FBGs with a phase shift between them. It can be proved that the phase shift of the FBG and the apodizing profile of the refractive index modulation determine the order of the transform. The device shows a good accuracy in calculating the Hilbert transform of the complex field of an arbitrary input optical waveforms when compared with the theoretical results.

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

Wu Shioumin; Kruijs, Robbert van de; Zoethout, Erwin

Ion sputtering yields for Ru, Mo, and Si under Ar{sup +} ion bombardment in the near-threshold energy range have been studied using an in situ weight-loss method with a Kaufman ion source, Faraday cup, and quartz crystal microbalance. The results are compared to theoretical models. The accuracy of the in situ weight-loss method was verified by thickness-decrease measurements using grazing incidence x-ray reflectometry, and results from both methods are in good agreement. These results provide accurate data sets for theoretical modeling in the near-threshold sputter regime and are of relevance for (optical) surfaces exposed to plasmas, as, for instance, inmore » extreme ultraviolet photolithography.« less

Northern Hemisphere observations of ICRF sources on the USNO stellar catalogue frame

NASA Astrophysics Data System (ADS)

Fienga, A.; Andrei, A. H.

2004-06-01

The most recent USNO stellar catalogue, the USNO B1.0 (Monet et al. \\cite{Monet03}), provides positions for 1 042 618 261 objects, with a published astrometric accuracy of 200 mas and five-band magnitudes with a 0.3 mag accuracy. Its completeness is believed to be up to magnitude 21th in V-band. Such a catalogue would be a very good tool for astrometric reduction. This work investigates the accuracy of the USNO B1.0 link to ICRF and give an estimation of its internal and external accuracies by comparison with different catalogues, and by computation of ICRF sources using USNO B1.0 star positions.

DJ-1 is a reliable serum biomarker for discriminating high-risk endometrial cancer.

PubMed

Di Cello, Annalisa; Di Sanzo, Maddalena; Perrone, Francesca Marta; Santamaria, Gianluca; Rania, Erika; Angotti, Elvira; Venturella, Roberta; Mancuso, Serafina; Zullo, Fulvio; Cuda, Giovanni; Costanzo, Francesco

2017-06-01

New reliable approaches to stratify patients with endometrial cancer into risk categories are highly needed. We have recently demonstrated that DJ-1 is overexpressed in endometrial cancer, showing significantly higher levels both in serum and tissue of patients with high-risk endometrial cancer compared with low-risk endometrial cancer. In this experimental study, we further extended our observation, evaluating the role of DJ-1 as an accurate serum biomarker for high-risk endometrial cancer. A total of 101 endometrial cancer patients and 44 healthy subjects were prospectively recruited. DJ-1 serum levels were evaluated comparing cases and controls and, among endometrial cancer patients, between high- and low-risk patients. The results demonstrate that DJ-1 levels are significantly higher in cases versus controls and in high- versus low-risk patients. The receiver operating characteristic curve analysis shows that DJ-1 has a very good diagnostic accuracy in discriminating endometrial cancer patients versus controls and an excellent accuracy in distinguishing, among endometrial cancer patients, low- from high-risk cases. DJ-1 sensitivity and specificity are the highest when high- and low-risk patients are compared, reaching the value of 95% and 99%, respectively. Moreover, DJ-1 serum levels seem to be correlated with worsening of the endometrial cancer grade and histotype, making it a reliable tool in the preoperative decision-making process.

High-resolution metal artifact reduction MR imaging of the lumbosacral plexus in patients with metallic implants.

PubMed

Ahlawat, Shivani; Stern, Steven E; Belzberg, Allan J; Fritz, Jan

2017-07-01

To assess the quality and accuracy of metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) for the diagnosis of lumbosacral neuropathies in patients with metallic implants in the pelvis. Twenty-two subjects with lumbosacral neuropathy following pelvic instrumentation underwent 1.5-T MARS MRI including optimized axial intermediate-weighted and STIR turbo spin echo sequences extending from L5 to the ischial tuberosity. Two readers graded the visibility of the lumbosacral trunk, sciatic, femoral, lateral femoral cutaneous, and obturator nerves and the nerve signal intensity of nerve, architecture, caliber, course, continuity, and skeletal muscle denervation. Clinical examination and electrodiagnostic studies were used as the standard of reference. Descriptive, agreement, and diagnostic performance statistics were applied. Lumbosacral plexus visibility on MARS MRI was good (4) or very good (3) in 92% of cases with 81% exact agreement and a Kendall's W coefficient of 0.811. The obturator nerve at the obturator foramen and the sciatic nerve posterior to the acetabulum had the lowest visibility, with good or very good ratings in only 61% and 77% of cases respectively. The reader agreement for nerve abnormalities on MARS MRI was excellent, ranging from 95.5 to 100%. MARS MRI achieved a sensitivity of 86%, specificity of 67%, positive predictive value of 95%, and negative predictive value of 40%, and accuracy of 83% for the detection of neuropathy. MARS MRI yields high image quality and diagnostic accuracy for the assessment of lumbosacral neuropathies in patients with metallic implants of the pelvis and hips.

Quantifying glenoid bone loss in anterior shoulder instability: reliability and accuracy of 2-dimensional and 3-dimensional computed tomography measurement techniques.

PubMed

Bois, Aaron J; Fening, Stephen D; Polster, Josh; Jones, Morgan H; Miniaci, Anthony

2012-11-01

Glenoid support is critical for stability of the glenohumeral joint. An accepted noninvasive method of quantifying glenoid bone loss does not exist. To perform independent evaluations of the reliability and accuracy of standard 2-dimensional (2-D) and 3-dimensional (3-D) computed tomography (CT) measurements of glenoid bone deficiency. Descriptive laboratory study. Two sawbone models were used; one served as a model for 2 anterior glenoid defects and the other for 2 anteroinferior defects. For each scapular model, predefect and defect data were collected for a total of 6 data sets. Each sample underwent 3-D laser scanning followed by CT scanning. Six physicians measured linear indicators of bone loss (defect length and width-to-length ratio) on both 2-D and 3-D CT and quantified bone loss using the glenoid index method on 2-D CT and using the glenoid index, ratio, and Pico methods on 3-D CT. The intraclass correlation coefficient (ICC) was used to assess agreement, and percentage error was used to compare radiographic and true measurements. With use of 2-D CT, the glenoid index and defect length measurements had the least percentage error (-4.13% and 7.68%, respectively); agreement was very good (ICC, .81) for defect length only. With use of 3-D CT, defect length (0.29%) and the Pico(1) method (4.93%) had the least percentage error. Agreement was very good for all linear indicators of bone loss (range, .85-.90) and for the ratio linear and Pico surface area methods used to quantify bone loss (range, .84-.98). Overall, 3-D CT results demonstrated better agreement and accuracy compared to 2-D CT. None of the methods assessed in this study using 2-D CT was found to be valid, and therefore, 2-D CT is not recommended for these methods. However, the length of glenoid defects can be reliably and accurately measured on 3-D CT. The Pico and ratio techniques are most reliable; however, the Pico(1) method accurately quantifies glenoid bone loss in both the anterior and anteroinferior locations. Future work is required to implement valid imaging techniques of glenoid bone loss into clinical practice. This is one of the only studies to date that has investigated both the reliability and accuracy of multiple indicators and quantification methods that evaluate glenoid bone loss in anterior glenohumeral instability. These data are critical to ensure valid methods are used for preoperative assessment and to determine when a glenoid bone augmentation procedure is indicated.

Development of an LC-MS/MS method for the determination of endogenous cortisol in hair using (13)C3-labeled cortisol as surrogate analyte.

PubMed

Binz, Tina M; Braun, Ueli; Baumgartner, Markus R; Kraemer, Thomas

2016-10-15

Hair cortisol levels are increasingly applied as a measure for stress in humans and mammals. Cortisol is an endogenous compound and is always present within the hair matrix. Therefore, "cortisol-free hair matrix" is a critical point for any analytical method to accurately quantify especially low cortisol levels. The aim of this project was to modify current methods used for hair cortisol analysis to more accurately determine low endogenous cortisol concentrations in hair. For that purpose, (13)C3-labeled cortisol, which is not naturally present in hair (above 13C natural abundance levels), was used for calibration and comparative validation applying cortisol versus (13)C3-labeled cortisol. Cortisol was extracted from 20mg hair (standard sample amount) applying an optimized single step extraction protocol. An LC-MS/MS method was developed for the quantitative analysis of cortisol using either cortisol or (13)C3-cortisol as calibrators and D7-cortisone as internal standard (IS). The two methods (cortisol/(13)C3-labeled cortisol) were validated in a concentration range up to 500pg/mg and showed good linearity for both analytes (cortisol: R(2)=0.9995; (13)C3-cortisol R(2)=0.9992). Slight differences were observed for limit of detection (LOD) (0.2pg/mg/0.1pg/mg) and limit of quantification (LOQ) (1pg/mg/0.5pg/mg). Precision was good with a maximum deviation of 8.8% and 10% for cortisol and (13)C3-cortisol respectively. Accuracy and matrix effects were good for both analytes except for the quality control (QC) low cortisol. QC low (2.5pg/mg) showed matrix effects (126.5%, RSD 35.5%) and accuracy showed a deviation of 26% when using cortisol to spike. These effects are likely to be caused by the unknown amount of endogenous cortisol in the different hair samples used to determine validation parameters like matrix effect, LOQ and accuracy. No matrix effects were observed for the high QC (400pg/mg) samples. Recovery was good with 92.7%/87.3% (RSD 9.9%/6.2%) for QC low and 102.3%/82.1% (RSD 5.8%/11.4%) for QC high. After successful validation the applicability of the method could be proven. The study shows that the method is especially useful for determining low endogenous cortisol concentrations as they occur in cow hair for example. Copyright © 2016 Elsevier B.V. All rights reserved.

A High-Precision Counter Using the DSP Technique

DTIC Science & Technology

2004-09-01

DSP is not good enough to process all the 1-second samples. The cache memory is also not sufficient to store all the sampling data. So we cut the...sampling number in a cycle is not good enough to achieve an accuracy less than 2×10-11. For this reason, a correlation operation is performed for... not good enough to process all the 1-second samples. The cache memory is also not sufficient to store all the sampling data. We will solve this

Feature selection and classifier parameters estimation for EEG signals peak detection using particle swarm optimization.

PubMed

Adam, Asrul; Shapiai, Mohd Ibrahim; Tumari, Mohd Zaidi Mohd; Mohamad, Mohd Saberi; Mubin, Marizan

2014-01-01

Electroencephalogram (EEG) signal peak detection is widely used in clinical applications. The peak point can be detected using several approaches, including time, frequency, time-frequency, and nonlinear domains depending on various peak features from several models. However, there is no study that provides the importance of every peak feature in contributing to a good and generalized model. In this study, feature selection and classifier parameters estimation based on particle swarm optimization (PSO) are proposed as a framework for peak detection on EEG signals in time domain analysis. Two versions of PSO are used in the study: (1) standard PSO and (2) random asynchronous particle swarm optimization (RA-PSO). The proposed framework tries to find the best combination of all the available features that offers good peak detection and a high classification rate from the results in the conducted experiments. The evaluation results indicate that the accuracy of the peak detection can be improved up to 99.90% and 98.59% for training and testing, respectively, as compared to the framework without feature selection adaptation. Additionally, the proposed framework based on RA-PSO offers a better and reliable classification rate as compared to standard PSO as it produces low variance model.

MR Fingerprinting Using The Quick Echo Splitting NMR Imaging Technique

PubMed Central

Jiang, Yun; Ma, Dan; Jerecic, Renate; Duerk, Jeffrey; Seiberlich, Nicole; Gulani, Vikas; Griswold, Mark A.

2016-01-01

Purpose The purpose of the study is to develop a quantitative method for the relaxation properties with a reduced radio frequency (RF) power deposition by combining Magnetic Resonance Fingerprinting (MRF) technique with Quick Echo Splitting NMR Imaging Technique (QUEST). Methods A QUEST-based MRF sequence was implemented to acquire high order echoes by increasing the gaps between RF pulses. Bloch simulations were used to calculate a dictionary containing the range of physically plausible signal evolutions using a range of T1 and T2 values based on the pulse sequence. MRF-QUEST was evaluated by comparing to the results of spin-echo methods. The SAR of QUEST-MRF was compared to the clinically available methods. Results MRF-QUEST quantifies the relaxation properties with good accuracy at the estimated head Specific Absorption Rate (SAR) of 0.03 W/kg. T1 and T2 values estimated by MRF-QUEST are in good agreement with the traditional methods. Conclusion The combination of the MRF and the QUEST provides an accurate quantification of T1 and T2 simultaneously with reduced RF power deposition. The resulting lower SAR may provide a new acquisition strategy for MRF when RF energy deposition is problematic. PMID:26924639

Analysis Article on the Performance Analysis of the OneTouch® UltraVue™ Blood Glucose Monitoring System

PubMed Central

Solnica, Bogdan

2009-01-01

In this issue of Journal of Diabetes Science and Technology, Chang and colleagues present the analytical performance evaluation of the OneTouch® UltraVue™ blood glucose meter. This device is an advanced construction with a color display, used-strip ejector, no-button interface, and short assay time. Accuracy studies were performed using a YSI 2300 analyzer, considered the reference. Altogether, 349 pairs of results covering a wide range of blood glucose concentrations were analyzed. Patients with diabetes performed a significant part of the tests. Obtained results indicate good accuracy of OneTouch UltraVue blood glucose monitoring system, satisfying the International Organization for Standardization recommendations and thereby locating >95% of tests within zone A of the error grid. Results of the precision studies indicate good reproducibility of measurements. In conclusion, the evaluation of the OneTouch UltraVue meter revealed good analytical performance together with convenient handling useful for self-monitoring of blood glucose performed by elderly diabetes patients. PMID:20144432

Analysis article on the performance analysis of the OneTouch UltraVue blood glucose monitoring system.

PubMed

Solnica, Bogdan

2009-09-01

In this issue of Journal of Diabetes Science and Technology, Chang and colleagues present the analytical performance evaluation of the OneTouch UltraVue blood glucose meter. This device is an advanced construction with a color display, used-strip ejector, no-button interface, and short assay time. Accuracy studies were performed using a YSI 2300 analyzer, considered the reference. Altogether, 349 pairs of results covering a wide range of blood glucose concentrations were analyzed. Patients with diabetes performed a significant part of the tests. Obtained results indicate good accuracy of OneTouch UltraVue blood glucose monitoring system, satisfying the International Organization for Standardization recommendations and thereby locating >95% of tests within zone A of the error grid. Results of the precision studies indicate good reproducibility of measurements. In conclusion, the evaluation of the OneTouch UltraVue meter revealed good analytical performance together with convenient handling useful for self-monitoring of blood glucose performed by elderly diabetes patients. 2009 Diabetes Technology Society.

System considerations for detection and tracking of small targets using passive sensors

NASA Astrophysics Data System (ADS)

DeBell, David A.

1991-08-01

Passive sensors provide only a few discriminants to assist in threat assessment of small targets. Tracking of the small targets provides additional discriminants. This paper discusses the system considerations for tracking small targets using passive sensors, in particular EO sensors. Tracking helps establish good versus bad detections. Discussed are the requirements to be placed on the sensor system's accuracy, with respect to knowledge of the sightline direction. The detection of weak targets sets a requirement for two levels of tracking in order to reduce processor throughput. A system characteristic is the need to track all detections. For low thresholds, this can mean a heavy track burden. Therefore, thresholds must be adaptive in order not to saturate the processors. Second-level tracks must develop a range estimate in order to assess threat. Sensor platform maneuvers are required if the targets are moving. The need for accurate pointing, good stability, and a good update rate will be shown quantitatively, relating to track accuracy and track association.

A neural-network-based model for the dynamic simulation of the tire/suspension system while traversing road irregularities.

PubMed

Guarneri, Paolo; Rocca, Gianpiero; Gobbi, Massimiliano

2008-09-01

This paper deals with the simulation of the tire/suspension dynamics by using recurrent neural networks (RNNs). RNNs are derived from the multilayer feedforward neural networks, by adding feedback connections between output and input layers. The optimal network architecture derives from a parametric analysis based on the optimal tradeoff between network accuracy and size. The neural network can be trained with experimental data obtained in the laboratory from simulated road profiles (cleats). The results obtained from the neural network demonstrate good agreement with the experimental results over a wide range of operation conditions. The NN model can be effectively applied as a part of vehicle system model to accurately predict elastic bushings and tire dynamics behavior. Although the neural network model, as a black-box model, does not provide a good insight of the physical behavior of the tire/suspension system, it is a useful tool for assessing vehicle ride and noise, vibration, harshness (NVH) performance due to its good computational efficiency and accuracy.

A novel scanning system using an industrial robot and the workspace measurement and positioning system

NASA Astrophysics Data System (ADS)

Zhao, Ziyue; Zhu, Jigui; Yang, Linghui; Lin, Jiarui

2015-10-01

The present scanning system consists of an industrial robot and a line-structured laser sensor which uses the industrial robot as a position instrument to guarantee the accuracy. However, the absolute accuracy of an industrial robot is relatively poor compared with the good repeatability in the manufacturing industry. This paper proposes a novel method using the workspace measurement and positioning system (wMPS) to remedy the lack of accuracy of the industrial robot. In order to guarantee the positioning accuracy of the system, the wMPS which is a laser-based measurement technology designed for large-volume metrology applications is brought in. Benefitting from the wMPS, this system can measure different cell-areas by the line-structured laser sensor and fuse the measurement data of different cell-areas by using the wMPS accurately. The system calibration which is the procedure to acquire and optimize the structure parameters of the scanning system is also stated in detail in this paper. In order to verify the feasibility of the system for scanning the large free-form surface, an experiment is designed to scan the internal surface of the door of a car-body in white. The final results show that the measurement data of the whole measuring areas have been jointed perfectly and there is no mismatch in the figure especially in the hole measuring areas. This experiment has verified the rationality of the system scheme, the correctness and effectiveness of the relevant methods.

Glucose Prediction Algorithms from Continuous Monitoring Data: Assessment of Accuracy via Continuous Glucose Error-Grid Analysis.

PubMed

Zanderigo, Francesca; Sparacino, Giovanni; Kovatchev, Boris; Cobelli, Claudio

2007-09-01

The aim of this article was to use continuous glucose error-grid analysis (CG-EGA) to assess the accuracy of two time-series modeling methodologies recently developed to predict glucose levels ahead of time using continuous glucose monitoring (CGM) data. We considered subcutaneous time series of glucose concentration monitored every 3 minutes for 48 hours by the minimally invasive CGM sensor Glucoday® (Menarini Diagnostics, Florence, Italy) in 28 type 1 diabetic volunteers. Two prediction algorithms, based on first-order polynomial and autoregressive (AR) models, respectively, were considered with prediction horizons of 30 and 45 minutes and forgetting factors (ff) of 0.2, 0.5, and 0.8. CG-EGA was used on the predicted profiles to assess their point and dynamic accuracies using original CGM profiles as reference. Continuous glucose error-grid analysis showed that the accuracy of both prediction algorithms is overall very good and that their performance is similar from a clinical point of view. However, the AR model seems preferable for hypoglycemia prevention. CG-EGA also suggests that, irrespective of the time-series model, the use of ff = 0.8 yields the highest accurate readings in all glucose ranges. For the first time, CG-EGA is proposed as a tool to assess clinically relevant performance of a prediction method separately at hypoglycemia, euglycemia, and hyperglycemia. In particular, we have shown that CG-EGA can be helpful in comparing different prediction algorithms, as well as in optimizing their parameters.

Facial emotion recognition and borderline personality pathology.

PubMed

Meehan, Kevin B; De Panfilis, Chiara; Cain, Nicole M; Antonucci, Camilla; Soliani, Antonio; Clarkin, John F; Sambataro, Fabio

2017-09-01

The impact of borderline personality pathology on facial emotion recognition has been in dispute; with impaired, comparable, and enhanced accuracy found in high borderline personality groups. Discrepancies are likely driven by variations in facial emotion recognition tasks across studies (stimuli type/intensity) and heterogeneity in borderline personality pathology. This study evaluates facial emotion recognition for neutral and negative emotions (fear/sadness/disgust/anger) presented at varying intensities. Effortful control was evaluated as a moderator of facial emotion recognition in borderline personality. Non-clinical multicultural undergraduates (n = 132) completed a morphed facial emotion recognition task of neutral and negative emotional expressions across different intensities (100% Neutral; 25%/50%/75% Emotion) and self-reported borderline personality features and effortful control. Greater borderline personality features related to decreased accuracy in detecting neutral faces, but increased accuracy in detecting negative emotion faces, particularly at low-intensity thresholds. This pattern was moderated by effortful control; for individuals with low but not high effortful control, greater borderline personality features related to misattributions of emotion to neutral expressions, and enhanced detection of low-intensity emotional expressions. Individuals with high borderline personality features may therefore exhibit a bias toward detecting negative emotions that are not or barely present; however, good self-regulatory skills may protect against this potential social-cognitive vulnerability. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Recall accuracy of mobile phone calls among Japanese young people.

PubMed

Kiyohara, Kosuke; Wake, Kanako; Watanabe, Soichi; Arima, Takuji; Sato, Yasuto; Kojimahara, Noriko; Taki, Masao; Yamaguchi, Naohito

2016-11-01

This study aimed to elucidate the recall accuracy of mobile phone calls among young people using new software-modified phone (SMP) technology. A total of 198 Japanese students aged between 10 and 24 years were instructed to use a SMP for 1 month to record their actual call statuses. Ten to 12 months after this period, face-to-face interviews were conducted to obtain the self-reported call statuses during the monitoring period. Using the SMP record as the gold standard of validation, the recall accuracy of phone calls was evaluated. A total of 19% of the participants (34/177) misclassified their laterality (i.e., the dominant side of ear used while making calls), with the level of agreement being moderate (κ-statistics, 0.449). The level of agreement between the self-reports and SMP records was relatively good for the duration of calls (Pearson's r, 0.620), as compared with the number of calls (Pearson's r, 0.561). The recall was prone to small systematic and large random errors for both the number and duration of calls. Such a large random recall error for the amount of calls and misclassification of laterality suggest that the results of epidemiological studies of mobile phone use based on self-assessment should be interpreted cautiously.

Rectal Tumour Staging with Endorectal Ultrasound: Is There Any Difference between Western and Eastern European Countries?

PubMed

Fábián, Anna; Bor, Renáta; Farkas, Klaudia; Bálint, Anita; Milassin, Ágnes; Rutka, Mariann; Tiszlavicz, László; Wittmann, Tibor; Nagy, Ferenc; Molnár, Tamás; Szepes, Zoltán

2016-01-01

Background. Rectal tumour management depends highly on locoregional extension. Rectal endoscopic ultrasound (ERUS) is a good alternative to computed tomography and magnetic resonance imaging. However, in Hungary only a small amount of rectal tumours is examined with ERUS. Methods. Our retrospective study (2006-2012) evaluates the diagnostic accuracy of ERUS and compares the results, the first data from Central Europe, with those from Western Europe. The effect of neoadjuvant therapy, rectal probe type, and investigator's experience were also assessed. Results. 311 of the 647 ERUS assessed locoregional extension. Histological comparison was available in 177 cases: 67 patients underwent surgery alone; 110 received neoadjuvant chemoradiotherapy (CRT); ERUS preceded CRT in 77 and followed it in 33 patients. T-staging was accurate in 72% of primarily operated patients. N-staging was less accurate (62%). CRT impaired staging accuracy (64% and 59% for T- and N-staging). Rigid probes were more accurate (79%). At least 30 examinations are needed to master the technique. Conclusions. The sensitivity of ERUS complies with the literature. ERUS is easy to learn and more accurate in early stages but unnecessary for restaging after CRT. Staging accuracy is similar in Western and Central Europe, although the number of examinations should be increased.

High-resolution myocardial stress perfusion at 3 T in patients with suspected coronary artery disease.

PubMed

Meyer, Carsten; Strach, Katharina; Thomas, Daniel; Litt, Harold; Nähle, Claas P; Tiemann, Klaus; Schwenger, Ulrich; Schild, Hans H; Sommer, Torsten

2008-02-01

To implement a high-resolution first-pass myocardial perfusion imaging protocol (HRPI) at 3 T, and to evaluate the feasibility, image quality and accuracy of this approach prospectively in patients with suspected CAD. We hypothesized that utilizing the gain in SNR at 3 T to increase spatial resolution would reduce partial volume effects and subendocardial dark rim artifacts in comparison to 1.5 T. HRPI studies were performed on 60 patients using a segmented k-space gradient echo sequence (in plane resolution 1.97 x 1.94 mm(2)). Semiquantitative assessment of dark rim artifacts was performed for the stress studies on a slice-by-slice basis. Qualitative visual analysis was compared to quantitative coronary angiography (QCA) results; hemodynamically significant CAD was defined as stenosis >or=70% at QCA. Dark rim artifacts appeared in 108 of 180 slices (average extent 1.3 +/- 1.2 mm representing 11.8 +/- 10.8% of the transmural myocardial thickness). Sensitivity, specifity, and test accuracy for the detection of significant CAD were 89%,79%, and 85%. HRPI studies at 3 T are feasible in a clinical setting, providing good image quality and high accuracy for detection of significant CAD. The presence of dark rim artifacts does not appear to represent a diagnostic problem when using a HRPI approach.

The inverted cup device for blood transfer on malaria RDTs: ease of use, acceptability and safety in routine use by health workers in Nigeria.

PubMed

Incardona, Sandra; Mwancha-Kwasa, Magoma; Rees-Channer, Roxanne R; Albertini, Audrey; Havumaki, Joshua; Chiodini, Peter; Oyibo, Wellington; Gonzalez, Iveth J

2018-01-15

Malaria rapid diagnostic tests (RDTs) are becoming widely adopted for case management at community level. However, reports and anecdotal observations indicate that the blood transfer step poses a significant challenge to many users. This study sought to evaluate the inverted cup device in the hands of health workers in everyday clinical practice, in comparison with the plastic pipette, and to determine the volume accuracy of the device made of a lower-cost plastic. The volume accuracy of inverted cup devices made of two plastics, PMMA and SBC, was compared by transferring blood 150 times onto filter paper and comparing the blood spot areas with those produced by 20 reference transfers with a calibrated micropipette. The ease of use, safety and acceptability of the inverted cup device and the pipette were evaluated by 50 health workers in Nigeria. Observations were recorded on pre-designed questionnaires, by the health workers themselves and by trained observers. Focus group discussions were also conducted. The volume accuracy assessment showed that the device made from the low-cost material (SBC) delivered a more accurate volume (mean 5.4 μL, SD 0.48 μL, range 4.5-7.0 μL) than the PMMA device (mean 5.9 μL, SD 0.48 μL, range 4.9-7.2 μL). The observational evaluation demonstrated that the inverted cup device performed better than the pipette in all aspects, e.g. higher proportions of health workers achieved successful blood collection (96%, vs. 66%), transfer of the required blood volume (90%, vs. 58%), and blood deposit without any loss (95%, vs. 50%). Majority of health workers also considered it' very easy' to use (81%),'very appropriate' for everyday use (78%), and 50% of them reported that it was their preferred BTD. The good volume accuracy and high acceptability of the inverted cup device shown in this study, along with observed ease of use and safety in hands of health workers, further strengthens prior findings which demonstrated its higher accuracy as compared with other BTDs in a laboratory setting. Altogether, these studies suggest that the inverted cup device should replace other types of devices for use in day-to-day malaria diagnosis with RDTs.

Forecasting daily patient volumes in the emergency department.

PubMed

Jones, Spencer S; Thomas, Alun; Evans, R Scott; Welch, Shari J; Haug, Peter J; Snow, Gregory L

2008-02-01

Shifts in the supply of and demand for emergency department (ED) resources make the efficient allocation of ED resources increasingly important. Forecasting is a vital activity that guides decision-making in many areas of economic, industrial, and scientific planning, but has gained little traction in the health care industry. There are few studies that explore the use of forecasting methods to predict patient volumes in the ED. The goals of this study are to explore and evaluate the use of several statistical forecasting methods to predict daily ED patient volumes at three diverse hospital EDs and to compare the accuracy of these methods to the accuracy of a previously proposed forecasting method. Daily patient arrivals at three hospital EDs were collected for the period January 1, 2005, through March 31, 2007. The authors evaluated the use of seasonal autoregressive integrated moving average, time series regression, exponential smoothing, and artificial neural network models to forecast daily patient volumes at each facility. Forecasts were made for horizons ranging from 1 to 30 days in advance. The forecast accuracy achieved by the various forecasting methods was compared to the forecast accuracy achieved when using a benchmark forecasting method already available in the emergency medicine literature. All time series methods considered in this analysis provided improved in-sample model goodness of fit. However, post-sample analysis revealed that time series regression models that augment linear regression models by accounting for serial autocorrelation offered only small improvements in terms of post-sample forecast accuracy, relative to multiple linear regression models, while seasonal autoregressive integrated moving average, exponential smoothing, and artificial neural network forecasting models did not provide consistently accurate forecasts of daily ED volumes. This study confirms the widely held belief that daily demand for ED services is characterized by seasonal and weekly patterns. The authors compared several time series forecasting methods to a benchmark multiple linear regression model. The results suggest that the existing methodology proposed in the literature, multiple linear regression based on calendar variables, is a reasonable approach to forecasting daily patient volumes in the ED. However, the authors conclude that regression-based models that incorporate calendar variables, account for site-specific special-day effects, and allow for residual autocorrelation provide a more appropriate, informative, and consistently accurate approach to forecasting daily ED patient volumes.

Evaluation of two portable meters for determination of blood triglyceride concentration in dogs.

PubMed

Kluger, Elissa K; Dhand, Navneet K; Malik, Richard; Ilkin, William J; Snow, David H; Govendir, Merran

2010-02-01

To evaluate agreement between 2 portable triglyceride meters and a veterinary laboratory for measurement of blood triglyceride concentrations in dogs and evaluate effects of Hct and blood volume analyzed. 97 blood samples collected from 60 dogs. Triglyceride concentrations were measured in blood by use of 2 meters and compared with serum triglyceride concentrations determined by a veterinary laboratory. Within- and between-day precision, accuracy, and effects of blood volume and Hct were analyzed. Accuracy of both meters varied with triglyceride concentration, although both accurately delineated dogs with triglyceride concentrations < 180 mg/dL versus > or = 180 mg/dL. One meter had results with excellent overall correlation with results of the standard laboratory method, with a concordance correlation coefficient of 0.94 and mean difference of 20.3 mg/dL. The other meter had a good overall concordance correlation coefficient of 0.86 with a higher absolute mean difference of -27.7 mg/dL. Results were only affected by blood volume; triglyceride concentrations determined via both meters were significantly lower when 7 microL of EDTA-anticoagulated blood was used, compared with larger volumes. 1 meter had greater accuracy in the range of 140 to 400 mg/dL and was therefore well suited to detect hypertriglyceridemia. The other meter was accurate with triglyceride values < 140 mg/dL and yielded results similar to those of the veterinary laboratory in the range of 140 to 400 mg/dL, therefore being suitable for determination of triglyceride concentrations in nonfed dogs and dogs with mildly high concentrations.

Accuracy in Rietveld quantitative phase analysis: a comparative study of strictly monochromatic Mo and Cu radiations.

PubMed

León-Reina, L; García-Maté, M; Álvarez-Pinazo, G; Santacruz, I; Vallcorba, O; De la Torre, A G; Aranda, M A G

2016-06-01

This study reports 78 Rietveld quantitative phase analyses using Cu  K α 1 , Mo  K α 1 and synchrotron radiations. Synchrotron powder diffraction has been used to validate the most challenging analyses. From the results for three series with increasing contents of an analyte (an inorganic crystalline phase, an organic crystalline phase and a glass), it is inferred that Rietveld analyses from high-energy Mo  K α 1 radiation have slightly better accuracies than those obtained from Cu  K α 1 radiation. This behaviour has been established from the results of the calibration graphics obtained through the spiking method and also from Kullback-Leibler distance statistic studies. This outcome is explained, in spite of the lower diffraction power for Mo radiation when compared to Cu radiation, as arising because of the larger volume tested with Mo and also because higher energy allows one to record patterns with fewer systematic errors. The limit of detection (LoD) and limit of quantification (LoQ) have also been established for the studied series. For similar recording times, the LoDs in Cu patterns, ∼0.2 wt%, are slightly lower than those derived from Mo patterns, ∼0.3 wt%. The LoQ for a well crystallized inorganic phase using laboratory powder diffraction was established to be close to 0.10 wt% in stable fits with good precision. However, the accuracy of these analyses was poor with relative errors near to 100%. Only contents higher than 1.0 wt% yielded analyses with relative errors lower than 20%.

Development, Calibration and Evaluation of a Portable and Direct Georeferenced Laser Scanning System for Kinematic 3D Mapping

NASA Astrophysics Data System (ADS)

Heinz, Erik; Eling, Christian; Wieland, Markus; Klingbeil, Lasse; Kuhlmann, Heiner

2015-12-01

In recent years, kinematic laser scanning has become increasingly popular because it offers many benefits compared to static laser scanning. The advantages include both saving of time in the georeferencing and a more favorable scanning geometry. Often mobile laser scanning systems are installed on wheeled platforms, which may not reach all parts of the object. Hence, there is an interest in the development of portable systems, which remain operational even in inaccessible areas. The development of such a portable laser scanning system is presented in this paper. It consists of a lightweight direct georeferencing unit for the position and attitude determination and a small low-cost 2D laser scanner. This setup provides advantages over existing portable systems that employ heavy and expensive 3D laser scanners in a profiling mode. A special emphasis is placed on the system calibration, i. e. the determination of the transformation between the coordinate frames of the direct georeferencing unit and the 2D laser scanner. To this end, a calibration field is used, which consists of differently orientated georeferenced planar surfaces, leading to estimates for the lever arms and boresight angles with an accuracy of mm and one-tenth of a degree. Finally, point clouds of the mobile laser scanning system are compared with georeferenced point clouds of a high-precision 3D laser scanner. Accordingly, the accuracy of the system is in the order of cm to dm. This is in good agreement with the expected accuracy, which has been derived from the error propagation of previously estimated variance components.

Can we measure the ankle-brachial index using only a stethoscope? A pilot study.

PubMed

Carmo, G A L; Mandil, A; Nascimento, B R; Arantes, B D; Bittencourt, J C; Falqueto, E B; Ribeiro, A L

2009-02-01

Ankle-brachial index (ABI) is an excellent method for the diagnosis of peripheral arterial disease (PAD) when it is performed with Doppler. However, this device is not always available for primary care physicians. The ABI measured with stethoscope is an easy alternative approach, but have not been proved to be useful. To assess the accuracy of the ABI measured using a stethoscope comparatively to that of the current eligible method for the diagnosis of PAD, the Doppler ABI, and describe the characteristics of this new approach. We conducted a diagnostic study of ABI measured with a stethoscope and a Doppler probe and compared the results. Eighty-eight patients were accessed by both methods. Mean stethoscope ABI, 1.01 +/- 0.15, and mean Doppler ABI, 1.03 +/- 0.20, (P = 0.047) displayed a good correlation. Measurements of stethoscope ABI diagnostic accuracy in recognizing a Doppler ABI are described. The comparison of this data with the current gold standard method results gave a sensitivity of 71.4% [95% confidence interval (CI), 41.9-91.6] and specificity of 91.0% (95% CI, 81.5-96.6), with predictive positive value of 62.5% (95% CI, 38.6-81.5) and negative predictive value of 93.8% (95% CI, 85.2-97.6). The study accuracy was 87.7%. The area under the ROC curve was 0.895 (95% CI, 0.804-0.986, P < 0.0001). According to our study, the stethoscope ABI is a useful method to detect PAD and it may be suitable for its screening in the primary care setting.

Accuracy and stability of measuring GABA, glutamate, and glutamine by proton magnetic resonance spectroscopy: A phantom study at 4 Tesla

PubMed Central

Henry, Michael E.; Lauriat, Tara L.; Shanahan, Meghan; Renshaw, Perry F.; Jensen, J. Eric

2015-01-01

Proton magnetic resonance spectroscopy has the potential to provide valuable information about alterations in gamma-aminobutyric acid (GABA), glutamate (Glu), and glutamine (Gln) in psychiatric and neurological disorders. In order to use this technique effectively, it is important to establish the accuracy and reproducibility of the methodology. In this study, phantoms with known metabolite concentrations were used to compare the accuracy of 2D J-resolved MRS, single-echo 30 ms PRESS, and GABA-edited MEGA-PRESS for measuring all three aforementioned neurochemicals simultaneously. The phantoms included metabolite concentrations above and below the physiological range and scans were performed at baseline, 1 week, and 1 month time-points. For GABA measurement, MEGA-PRESS proved optimal with a measured-to-target correlation of R2 = 0.999, with J-resolved providing R2 = 0.973 for GABA. All three methods proved effective in measuring Glu with R2 = 0.987 (30 ms PRESS), R2 = 0.996 (J-resolved) and R2 = 0.910 (MEGA-PRESS). J-resolved and MEGA-PRESS yielded good results for Gln measures with respective R2 = 0.855 (J-resolved) and R2 = 0.815 (MEGA-PRESS). The 30 ms PRESS method proved ineffective in measuring GABA and Gln. When measurement stability at in vivo concentration was assessed as a function of varying spectral quality, J-resolved proved the most stable and immune to signal-to-noise and linewidth fluctuation compared to MEGA-PRESS and 30 ms PRESS. PMID:21130670

Symmetry Breaking and the B3LYP Functional

NASA Technical Reports Server (NTRS)

Bauschlicher, Charles W., Jr.; Hudgins, Douglas M.; Allamandola, Louis J.; Arnold, James O. (Technical Monitor)

1999-01-01

The infrared spectra of six molecules, each of which contains a five-membered ring, and their cations are determined using density functional theory (DFT); both the B3LYP and BP86 functionals are used. The computed results are compared with the experimental spectra. For the neutral molecules, both methods are in good agreement with experiment. Even the Hartree-Fock (HF) approach is qualitatively correct for the neutrals. For the cations, the HF approach fails, as found for other organic ring systems. The B3LYP and BP86 approaches are in good mutual agreement for five of the six cation spectra, and in good agreement with experiment for four of the five cations where the experimental spectra are available. It is only for the fluoranthene cation, where the BP86 and B3LYP functionals yield different results; the BP86 yields the expected C2v symmetry, while the B3LYP approach breaks symmetry. The experimental spectra supports the BP86 spectra over the B3LYP, but the quality of the experimental spectra does not allow a critical evaluation of the accuracy of the BP86 approach for this difficult system.

Accuracy and borehole influences in pulsed neutron gamma density logging while drilling.

PubMed

Yu, Huawei; Sun, Jianmeng; Wang, Jiaxin; Gardner, Robin P

2011-09-01

A new pulsed neutron gamma density (NGD) logging has been developed to replace radioactive chemical sources in oil logging tools. The present paper describes studies of near and far density measurement accuracy of NGD logging at two spacings and the borehole influences using Monte-Carlo simulation. The results show that the accuracy of near density is not as good as far density. It is difficult to correct this for borehole effects by using conventional methods because both near and far density measurement is significantly sensitive to standoffs and mud properties. Copyright © 2011 Elsevier Ltd. All rights reserved.

Dissimilarity representations in lung parenchyma classification

NASA Astrophysics Data System (ADS)

Sørensen, Lauge; de Bruijne, Marleen

2009-02-01

A good problem representation is important for a pattern recognition system to be successful. The traditional approach to statistical pattern recognition is feature representation. More specifically, objects are represented by a number of features in a feature vector space, and classifiers are built in this representation. This is also the general trend in lung parenchyma classification in computed tomography (CT) images, where the features often are measures on feature histograms. Instead, we propose to build normal density based classifiers in dissimilarity representations for lung parenchyma classification. This allows for the classifiers to work on dissimilarities between objects, which might be a more natural way of representing lung parenchyma. In this context, dissimilarity is defined between CT regions of interest (ROI)s. ROIs are represented by their CT attenuation histogram and ROI dissimilarity is defined as a histogram dissimilarity measure between the attenuation histograms. In this setting, the full histograms are utilized according to the chosen histogram dissimilarity measure. We apply this idea to classification of different emphysema patterns as well as normal, healthy tissue. Two dissimilarity representation approaches as well as different histogram dissimilarity measures are considered. The approaches are evaluated on a set of 168 CT ROIs using normal density based classifiers all showing good performance. Compared to using histogram dissimilarity directly as distance in a emph{k} nearest neighbor classifier, which achieves a classification accuracy of 92.9%, the best dissimilarity representation based classifier is significantly better with a classification accuracy of 97.0% (text{emph{p" border="0" class="imgtopleft"> = 0.046).

The Herschel Multi-Tiered Extragalactic Survey: SPIRE-mm Photometric Redshifts

NASA Technical Reports Server (NTRS)

Roseboom, I. G.; Ivison, R. J.; Greve, T. R.; Amblard, A.; Arumugam, V.; Auld, R.; Aussel, H.; Bethermin, M.; Blain, A.; Bock, J.;

Modelling Multi Hazard Mapping in Semarang City Using GIS-Fuzzy Method

NASA Astrophysics Data System (ADS)

Nugraha, A. L.; Awaluddin, M.; Sasmito, B.

2018-02-01

One important aspect of disaster mitigation planning is hazard mapping. Hazard mapping can provide spatial information on the distribution of locations that are threatened by disaster. Semarang City as the capital of Central Java Province is one of the cities with high natural disaster intensity. Frequent natural disasters Semarang city is tidal flood, floods, landslides, and droughts. Therefore, Semarang City needs spatial information by doing multi hazard mapping to support disaster mitigation planning in Semarang City. Multi Hazards map modelling can be derived from parameters such as slope maps, rainfall, land use, and soil types. This modelling is done by using GIS method with scoring and overlay technique. However, the accuracy of modelling would be better if the GIS method is combined with Fuzzy Logic techniques to provide a good classification in determining disaster threats. The Fuzzy-GIS method will build a multi hazards map of Semarang city can deliver results with good accuracy and with appropriate threat class spread so as to provide disaster information for disaster mitigation planning of Semarang city. from the multi-hazard modelling using GIS-Fuzzy can be known type of membership that has a good accuracy is the type of membership Gauss with RMSE of 0.404 the smallest of the other membership and VAF value of 72.909% of the largest of the other membership.

Design and Application of Automatic Falling Device for Different Brands of Goods

NASA Astrophysics Data System (ADS)

Yang, Xudong; Ge, Qingkuan; Zuo, Ping; Peng, Tao; Dong, Weifu

2017-12-01

The Goods-Falling device is an important device in the intelligent sorting goods sorting system, which is responsible for the temporary storage and counting of the goods, and the function of putting the goods on the conveyor belt according to certain precision requirements. According to the present situation analysis and actual demand of the domestic goods sorting equipment, a vertical type Goods - Falling Device is designed and the simulation model of the device is established. The dynamic characteristics such as the angular error of the opening and closing mechanism are carried out by ADAMS software. The simulation results show that the maximum angular error is 0.016rad. Through the test of the device, the goods falling speed is 7031/hour, the good of the falling position error within 2mm, meet the crawl accuracy requirements of the palletizing robot.

Relationship between dean's letter rankings and later evaluations by residency program directors.

PubMed

Lurie, Stephen J; Lambert, David R; Grady-Weliky, Tana A

2007-01-01

It is not known how well dean's letter rankings predict later performance in residency. To assess the accuracy of dean's letter rankings to predict clinical performance in internship. Participants were medical students who graduated from the University of Rochester School of Medicine and Dentistry in the classes of 2003 and 2004. In their Dean's Letter, each student was ranked as either "Outstanding" (upper quartile), "Excellent" (second quartile), "Very good" (lower 2 quartiles), or "Good" (lowest few percentile). We compared these dean's letter rankings against results of questionnaires sent to program directors 9 months after graduation. Response rate to the questionnaire was 58.9% (109 of 185 eligible graduates). There were no differences in response rate across the four dean's letter ranking categories. Program directors rated students in the top two categories of dean's letter rankings significantly higher than those in the very good group. Students in all three groups were rated significantly higher than those in the good group, F (3, 105) = 13.37, p < .001. Students in the very good group were most variable in their ratings by program directors, with many receiving similarly high ratings as students in the upper 2 groups. There were no differences by gender or specialty. Dean's letter rankings are a significant predictor of later performance in internship among graduates of our medical school. Students in the bottom half of the class are most likely either to underperform or overperform in internship.

Diagnostic accuracy of CTA and MRI/MRA in the evaluation of the cortical venous reflux in the intracranial dural arteriovenous fistula DAVF.

PubMed

Lin, Yen-Heng; Wang, Yu-Fen; Liu, Hon-Man; Lee, Chung-Wei; Chen, Ya-Fang; Hsieh, Hong-Jen

2018-01-01

Computed tomography angiography (CTA) and magnetic resonance imaging/angiography (MRI/MRA) are used for the diagnosis of intracranial dural arteriovenous fistulas (DAVFs). The purpose of this study was to compare the diagnostic accuracy of CTA and magnetic resonance imaging/angiography (MRI/MRA) for detection of cortical venous reflux (CVR) in intracranial DAVFs. The records of patients with angiography-confirmed intracranial DAVFs who also received CTA and MRI/MRA from January 2008 to July 2016 were reviewed. CTA and MRI/MRA were reviewed for signs of CVR, and the diagnostic accuracy of individual signs was evaluated by receiver operating curve (ROC) analysis. A total 108 patients were included in this study. CTA signs of CVR included abnormal dilatation, early enhancement, and the presence of a medullary or pial vein. MRI/MRA signs of CVR included abnormal dilatation, early enhancement, flow-related enhancement, flow void, and medullary or pial venous collaterals. The sensitivity of individual CTA signs ranged from 62 to 96%, and specificities from 79 to 94%. The sensitivities of individual MRI/MRA signs ranged from 58 to 83%, and specificities from 77 to 93%. The area under ROC curve (AUC) of CTA and MRI/MRA were 0.91 and 0.87, respectively (P = 0.04 in direct comparison). In subgroup analysis, CTA had better diagnostic accuracy for higher grade disease (P = 0.05) and non-aggressive manifestation (P = 0.04). Both CTA and MRI/MRA have good diagnostic accuracy for detection of CVR in patients with intracranial DAVFs. There is modest evidence that CTA is better than MRI/MRA.

Diagnostic accuracy of a noninvasive hepatic ultrasound score for non-alcoholic fatty liver disease (NAFLD) in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

PubMed

Goulart, Alessandra Carvalho; Oliveira, Ilka Regina Souza de; Alencar, Airlane Pereira; Santos, Maira Solange Camara dos; Santos, Itamar Souza; Martines, Brenda Margatho Ramos; Meireles, Danilo Peron; Martines, João Augusto dos Santos; Misciagna, Giovanni; Benseñor, Isabela Martins; Lotufo, Paulo Andrade

2015-01-01

Noninvasive strategies for evaluating non-alcoholic fatty liver disease (NAFLD) have been investigated over the last few decades. Our aim was to evaluate the diagnostic accuracy of a new hepatic ultrasound score for NAFLD in the ELSA-Brasil study. Diagnostic accuracy study conducted in the ELSA center, in the hospital of a public university. Among the 15,105 participants of the ELSA study who were evaluated for NAFLD, 195 individuals were included in this sub-study. Hepatic ultrasound was performed (deep beam attenuation, hepatorenal index and anteroposterior diameter of the right hepatic lobe) and compared with the hepatic steatosis findings from 64-channel high-resolution computed tomography (CT). We also evaluated two clinical indices relating to NAFLD: the fatty liver index (FLI) and the hepatic steatosis index (HSI). Among the 195 participants, the NAFLD frequency was 34.4%. High body mass index, high waist circumference, diabetes and hypertriglyceridemia were associated with high hepatic attenuation and large anteroposterior diameter of the right hepatic lobe, but not with the hepatorenal index. The hepatic ultrasound score, based on hepatic attenuation and the anteroposterior diameter of the right hepatic lobe, presented the best performance for NAFLD screening at the cutoff point ≥ 1 point; sensitivity: 85.1%; specificity: 73.4%; accuracy: 79.3%; and area under the curve (AUC 0.85; 95% confidence interval, CI: 0.78-0.91)]. FLI and HSI presented lower performance (AUC 0.76; 95% CI: 0.69-0.83) than CT. The hepatic ultrasound score based on hepatic attenuation and the anteroposterior diameter of the right hepatic lobe has good reproducibility and accuracy for NAFLD screening.

Assessment of Different Discrete Particle Methods Ability To Predict Gas-Particle Flow in a Small-Scale Fluidized Bed

DOE PAGES

Lu, Liqiang; Gopalan, Balaji; Benyahia, Sofiane

2017-06-21

Several discrete particle methods exist in the open literature to simulate fluidized bed systems, such as discrete element method (DEM), time driven hard sphere (TDHS), coarse-grained particle method (CGPM), coarse grained hard sphere (CGHS), and multi-phase particle-in-cell (MP-PIC). These different approaches usually solve the fluid phase in a Eulerian fixed frame of reference and the particle phase using the Lagrangian method. The first difference between these models lies in tracking either real particles or lumped parcels. The second difference is in the treatment of particle-particle interactions: by calculating collision forces (DEM and CGPM), using momentum conservation laws (TDHS and CGHS),more » or based on particle stress model (MP-PIC). These major model differences lead to a wide range of results accuracy and computation speed. However, these models have never been compared directly using the same experimental dataset. In this research, a small-scale fluidized bed is simulated with these methods using the same open-source code MFIX. The results indicate that modeling the particle-particle collision by TDHS increases the computation speed while maintaining good accuracy. Also, lumping few particles in a parcel increases the computation speed with little loss in accuracy. However, modeling particle-particle interactions with solids stress leads to a big loss in accuracy with a little increase in computation speed. The MP-PIC method predicts an unphysical particle-particle overlap, which results in incorrect voidage distribution and incorrect overall bed hydrodynamics. Based on this study, we recommend using the CGHS method for fluidized bed simulations due to its computational speed that rivals that of MPPIC while maintaining a much better accuracy.« less

Accuracy of diagnostic imaging modalities for peripheral post-traumatic osteomyelitis - a systematic review of the recent literature.

PubMed

Govaert, Geertje A; IJpma, Frank F; McNally, Martin; McNally, Eugene; Reininga, Inge H; Glaudemans, Andor W

2017-08-01

Post-traumatic osteomyelitis (PTO) is difficult to diagnose and there is no consensus on the best imaging strategy. The aim of this study is to present a systematic review of the recent literature on diagnostic imaging of PTO. A literature search of the EMBASE and PubMed databases of the last 16 years (2000-2016) was performed. Studies that evaluated the accuracy of magnetic resonance imaging (MRI), three-phase bone scintigraphy (TPBS), white blood cell (WBC) or antigranulocyte antibody (AGA) scintigraphy, fluorodeoxyglucose positron emission tomography (FDG-PET) and plain computed tomography (CT) in diagnosing PTO were considered for inclusion. The review was conducted using the PRISMA statement and QUADAS-2 criteria. The literature search identified 3358 original records, of which 10 articles could be included in this review. Four of these studies had a comparative design which made it possible to report the results of, in total, 17 patient series. WBC (or AGA) scintigraphy and FDG-PET exhibit good accuracy for diagnosing PTO (sensitivity ranged from 50-100%, specificity ranged from 40-97% versus 83-100% and 51%-100%, respectively). The accuracy of both modalities improved when a hybrid imaging technique (SPECT/CT & FDG-PET/CT) was performed. For FDG-PET/CT, sensitivity ranged between 86 and 94% and specificity between 76 and 100%. For WBC scintigraphy + SPECT/CT, this is 100% and 89-97%, respectively. Based on the best available evidence of the last 16 years, both WBC (or AGA) scintigraphy combined with SPECT/CT or FDG-PET combined with CT have the best diagnostic accuracy for diagnosing peripheral PTO.

Numerical and clinical precision of continuous glucose monitoring in Colombian patients treated with insulin infusion pump with automated suspension in hypoglycemia.

PubMed

Gómez, Ana M; Marín Sánchez, Alejandro; Muñoz, Oscar M; Colón Peña, Christian Alejandro

2015-12-01

Insulin pump therapy associated with continuous glucose monitoring has shown a positive clinical impact on diabetes control and reduction of hypoglycemia episodes. There are descriptions of the performance of this device in other populations, but its precision and accuracy in Colombia and Latin America are unknown, especially in the routine outpatient setting. Data from 33 type 1 and type 2 diabetes patients with sensor-augmented pump therapy with threshold suspend automation, MiniMed Paradigm® Veo™ (Medtronic, Northridge, California), managed at Hospital Universitario San Ignacio (Bogotá, Colombia) and receiving outpatient treatment, were analyzed. Simultaneous data from continuous glucose monitoring and capillary blood glucose were compared, and their precision and accuracy were calculating with different methods, including Clarke error grid. Analyses included 2,262 continuous glucose monitoring -reference paired glucose values. A mean absolute relative difference of 20.1% was found for all measurements, with a value higher than 23% for glucose levels ≤75mg/dL. Global compliance with the ISO criteria was 64.9%. It was higher for values >75mg/dl (68.3%, 1,308 of 1,916 readings), than for those ≤ 75mg/dl (49.4%, 171 of 346 readings). Clinical accuracy, as assessed by the Clarke error grid, showed that 91.77% of data were within the A and B zones (75.6% in hypoglycemia). A good numerical accuracy was found for continuous glucose monitoring in normo and hyperglycemia situations, with low precision in hypoglycemia. The clinical accuracy of the device was adequate, with no significant safety concerns for patients. Copyright © 2015 SEEN. Published by Elsevier España, S.L.U. All rights reserved.

Improving zero-training brain-computer interfaces by mixing model estimators

NASA Astrophysics Data System (ADS)

Verhoeven, T.; Hübner, D.; Tangermann, M.; Müller, K. R.; Dambre, J.; Kindermans, P. J.

2017-06-01

Objective. Brain-computer interfaces (BCI) based on event-related potentials (ERP) incorporate a decoder to classify recorded brain signals and subsequently select a control signal that drives a computer application. Standard supervised BCI decoders require a tedious calibration procedure prior to every session. Several unsupervised classification methods have been proposed that tune the decoder during actual use and as such omit this calibration. Each of these methods has its own strengths and weaknesses. Our aim is to improve overall accuracy of ERP-based BCIs without calibration. Approach. We consider two approaches for unsupervised classification of ERP signals. Learning from label proportions (LLP) was recently shown to be guaranteed to converge to a supervised decoder when enough data is available. In contrast, the formerly proposed expectation maximization (EM) based decoding for ERP-BCI does not have this guarantee. However, while this decoder has high variance due to random initialization of its parameters, it obtains a higher accuracy faster than LLP when the initialization is good. We introduce a method to optimally combine these two unsupervised decoding methods, letting one method’s strengths compensate for the weaknesses of the other and vice versa. The new method is compared to the aforementioned methods in a resimulation of an experiment with a visual speller. Main results. Analysis of the experimental results shows that the new method exceeds the performance of the previous unsupervised classification approaches in terms of ERP classification accuracy and symbol selection accuracy during the spelling experiment. Furthermore, the method shows less dependency on random initialization of model parameters and is consequently more reliable. Significance. Improving the accuracy and subsequent reliability of calibrationless BCIs makes these systems more appealing for frequent use.

Comparison of 3T and 7T susceptibility-weighted angiography of the substantia nigra in diagnosing Parkinson disease.

PubMed

Cosottini, M; Frosini, D; Pesaresi, I; Donatelli, G; Cecchi, P; Costagli, M; Biagi, L; Ceravolo, R; Bonuccelli, U; Tosetti, M

2015-03-01

Standard neuroimaging fails in defining the anatomy of the substantia nigra and has a marginal role in the diagnosis of Parkinson disease. Recently 7T MR target imaging of the substantia nigra has been useful in diagnosing Parkinson disease. We performed a comparative study to evaluate whether susceptibility-weighted angiography can diagnose Parkinson disease with a 3T scanner. Fourteen patients with Parkinson disease and 13 healthy subjects underwent MR imaging examination at 3T and 7T by using susceptibility-weighted angiography. Two expert blinded observers and 1 neuroradiology fellow evaluated the 3T and 7T images of the sample to identify substantia nigra abnormalities indicative of Parkinson disease. Diagnostic accuracy and intra- and interobserver agreement were calculated separately for 3T and 7T acquisitions. Susceptibility-weighted angiography 7T MR imaging can diagnose Parkinson disease with a mean sensitivity of 93%, specificity of 100%, and diagnostic accuracy of 96%. 3T MR imaging diagnosed Parkinson disease with a mean sensitivity of 79%, specificity of 94%, and diagnostic accuracy of 86%. Intraobserver and interobserver agreement was excellent at 7T. At 3T, intraobserver agreement was excellent for experts, and interobserver agreement ranged between good and excellent. The less expert reader obtained a diagnostic accuracy of 89% at 3T. Susceptibility-weighted angiography images obtained at 3T and 7T differentiate controls from patients with Parkinson disease with a higher diagnostic accuracy at 7T. The capability of 3T in diagnosing Parkinson disease might encourage its use in clinical practice. The use of the more accurate 7T should be supported by a dedicated cost-effectiveness study. © 2015 by American Journal of Neuroradiology.

Accuracy of the raw-data-based effective atomic numbers and monochromatic CT numbers for contrast medium with a dual-energy CT technique.

PubMed

Kawahara, Daisuke; Ozawa, Shuichi; Yokomachi, Kazushi; Tanaka, Sodai; Higaki, Toru; Fujioka, Chikako; Suzuki, Tatsuhiko; Tsuneda, Masato; Nakashima, Takeo; Ohno, Yoshimi; Nagata, Yasushi

2018-02-01

To evaluate the accuracy of raw-data-based effective atomic number (Z eff ) values and monochromatic CT numbers for contrast material of varying iodine concentrations, obtained using dual-energy CT. We used a tissue characterization phantom and varying concentrations of iodinated contrast medium. A comparison between the theoretical values of Z eff and that provided by the manufacturer was performed. The measured and theoretical monochromatic CT numbers at 40-130 keV were compared. The average difference between the Z eff values of lung (inhale) inserts in the tissue characterization phantom was 81.3% and the average Z eff difference was within 8.4%. The average difference between the Z eff values of the varying concentrations of iodinated contrast medium was within 11.2%. For the varying concentrations of iodinated contrast medium, the differences between the measured and theoretical monochromatic CT values increased with decreasing monochromatic energy. The Z eff and monochromatic CT numbers in the tissue characterization phantom were reasonably accurate. The accuracy of the raw-data-based Z eff values was higher than that of image-based Z eff values in the tissue-equivalent phantom. The accuracy of Z eff values in the contrast medium was in good agreement within the maximum SD found in the iodine concentration range of clinical dynamic CT imaging. Moreover, the optimum monochromatic energy for human tissue and iodinated contrast medium was found to be 70 keV. Advances in knowledge: The accuracy of the Z eff values and monochromatic CT numbers of the contrast medium created by raw-data-based, dual-energy CT could be sufficient in clinical conditions.

Assessment of Different Discrete Particle Methods Ability To Predict Gas-Particle Flow in a Small-Scale Fluidized Bed

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

Lu, Liqiang; Gopalan, Balaji; Benyahia, Sofiane

Several discrete particle methods exist in the open literature to simulate fluidized bed systems, such as discrete element method (DEM), time driven hard sphere (TDHS), coarse-grained particle method (CGPM), coarse grained hard sphere (CGHS), and multi-phase particle-in-cell (MP-PIC). These different approaches usually solve the fluid phase in a Eulerian fixed frame of reference and the particle phase using the Lagrangian method. The first difference between these models lies in tracking either real particles or lumped parcels. The second difference is in the treatment of particle-particle interactions: by calculating collision forces (DEM and CGPM), using momentum conservation laws (TDHS and CGHS),more » or based on particle stress model (MP-PIC). These major model differences lead to a wide range of results accuracy and computation speed. However, these models have never been compared directly using the same experimental dataset. In this research, a small-scale fluidized bed is simulated with these methods using the same open-source code MFIX. The results indicate that modeling the particle-particle collision by TDHS increases the computation speed while maintaining good accuracy. Also, lumping few particles in a parcel increases the computation speed with little loss in accuracy. However, modeling particle-particle interactions with solids stress leads to a big loss in accuracy with a little increase in computation speed. The MP-PIC method predicts an unphysical particle-particle overlap, which results in incorrect voidage distribution and incorrect overall bed hydrodynamics. Based on this study, we recommend using the CGHS method for fluidized bed simulations due to its computational speed that rivals that of MPPIC while maintaining a much better accuracy.« less

Prediction of pathologic staging with magnetic resonance imaging after preoperative chemoradiotherapy in rectal cancer: pooled analysis of KROG 10-01 and 11-02.

PubMed

Lee, Jong Hoon; Jang, Hong Seok; Kim, Jun-Gi; Lee, Myung Ah; Kim, Dae Yong; Kim, Tae Hyun; Oh, Jae Hwan; Park, Sung Chan; Kim, Sun Young; Baek, Ji Yeon; Park, Hee Chul; Kim, Hee Cheol; Nam, Taek-Keun; Chie, Eui Kyu; Jung, Ji-Han; Oh, Seong Taek

2014-10-01

The reported overall accuracy of MRI in predicting the pathologic stage of nonirradiated rectal cancer is high. However, the role of MRI in restaging rectal tumors after neoadjuvant CRT is contentious. Thus, we evaluate the accuracy of restaging magnetic resonance imaging (MRI) for rectal cancer patients who receive preoperative chemoradiotherapy (CRT). We analyzed 150 patients with locally advanced rectal cancer (T3-4N0-2) who had received preoperative CRT. Pre-CRT MRI was performed for local tumor and nodal staging. All patients underwent restaging MRI followed by total mesorectal excision after the end of radiotherapy. The primary endpoint of the present study was to estimate the accuracy of post-CRT MRI as compared with pathologic staging. Pathologic T classification matched the post-CRT MRI findings in 97 (64.7%) of 150 patients. 36 (24.0%) of 150 patients were overstaged in T classification, and the concordance degree was moderate (k=0.33, p<0.01). Pathologic N classification matched the post-CRI MRI findings in 85 (56.6%) of 150 patients. 54 (36.0%) of 150 patients were overstaged in N classification. 26 patients achieved downstaging (ycT0-2N0) on restaging MRI after CRT. 23 (88.5%) of 26 patients who had been downstaged on MRI after CRT were confirmed on the pathological staging, and the concordance degree was good (k=0.72, p<0.01). Restaging MRI has low accuracy for the prediction of the pathologic T and N classifications in rectal cancer patients who received preoperative CRT. The diagnostic accuracy of restaging MRI is relatively high in rectal cancer patients who achieved clinical downstaging after CRT. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

First-principles anharmonic quantum calculations for peptide spectroscopy: VSCF calculations and comparison with experiments.

PubMed

Roy, Tapta Kanchan; Sharma, Rahul; Gerber, R Benny

2016-01-21

First-principles quantum calculations for anharmonic vibrational spectroscopy of three protected dipeptides are carried out and compared with experimental data. Using hybrid HF/MP2 potentials, the Vibrational Self-Consistent Field with Second-Order Perturbation Correction (VSCF-PT2) algorithm is used to compute the spectra without any ad hoc scaling or fitting. All of the vibrational modes (135 for the largest system) are treated quantum mechanically and anharmonically using full pair-wise coupling potentials to represent the interaction between different modes. In the hybrid potential scheme the MP2 method is used for the harmonic part of the potential and a modified HF method is used for the anharmonic part. The overall agreement between computed spectra and experiment is very good and reveals different signatures for different conformers. This study shows that first-principles spectroscopic calculations of good accuracy are possible for dipeptides hence it opens possibilities for determination of dipeptide conformer structures by comparison of spectroscopic calculations with experiment.

Thermogravimetric analysis for rapid assessment of moisture diffusivity in polydisperse powder and thin film matrices.

PubMed

Thirunathan, Praveena; Arnz, Patrik; Husny, Joeska; Gianfrancesco, Alessandro; Perdana, Jimmy

2018-03-01

Accurate description of moisture diffusivity is key to precisely understand and predict moisture transfer behaviour in a matrix. Unfortunately, measuring moisture diffusivity is not trivial, especially at low moisture values and/or elevated temperatures. This paper presents a novel experimental procedure to accurately measure moisture diffusivity based on thermogravimetric approach. The procedure is capable to measure diffusivity even at elevated temperatures (>70°C) and low moisture values (>1%). Diffusivity was extracted from experimental data based on "regular regime approach". The approach was tailored to determine diffusivity from thin film and from poly-dispersed powdered samples. Subsequently, measured diffusivity was validated by comparing to available literature data, showing good agreement. Ability of this approach to accurately measure diffusivity at a wider range of temperatures provides better insight on temperature dependency of diffusivity. Thus, this approach can be crucial to ensure good accuracy of moisture transfer description/prediction especially when involving elevated temperatures. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sustained modelling ability of artificial neural networks in the analysis of two pharmaceuticals (dextropropoxyphene and dipyrone) present in unequal concentrations.

PubMed

Cámara, María S; Ferroni, Félix M; De Zan, Mercedes; Goicoechea, Héctor C

2003-07-01

An improvement is presented on the simultaneous determination of two active ingredients present in unequal concentrations in injections. The analysis was carried out with spectrophotometric data and non-linear multivariate calibration methods, in particular artificial neural networks (ANNs). The presence of non-linearities caused by the major analyte concentrations which deviate from Beer's law was confirmed by plotting actual vs. predicted concentrations, and observing curvatures in the residuals for the estimated concentrations with linear methods. Mixtures of dextropropoxyphene and dipyrone have been analysed by using linear and non-linear partial least-squares (PLS and NPLSs) and ANNs. Notwithstanding the high degree of spectral overlap and the occurrence of non-linearities, rapid and simultaneous analysis has been achieved, with reasonably good accuracy and precision. A commercial sample was analysed by using the present methodology, and the obtained results show reasonably good agreement with those obtained by using high-performance liquid chromatography (HPLC) and a UV-spectrophotometric comparative methods.

Analytical formulas for short bunch wakes in a flat dechirper

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

Bane, Karl; Stupakov, Gennady; Zagorodnov, Igor

2016-08-04

We develop analytical models of the longitudinal and transverse wakes, on and off axis for a flat, corrugated beam pipe with realistic parameters, and then compare them with numerical calculations, and generally find good agreement. These analytical “first order” formulas approximate the droop at the origin of the longitudinal wake and of the slope of the transverse wakes; they represent an improvement in accuracy over earlier, “zeroth order” formulas. In example calculations for the RadiaBeam/LCLS dechirper using typical parameters, we find a 16% droop in the energy chirp at the bunch tail compared to simpler calculations. As a result, withmore » the beam moved to 200 μm from one jaw in one dechirper section, one can achieve a 3 MV transverse kick differential over a 30 μm length.« less

A Sequence Mining Method to Predict the Bidding Strategy of Trading Agents

NASA Astrophysics Data System (ADS)

Nikolaidou, Vivia; Mitkas, Pericles A.

In this work, we describe the process used in order to predict the bidding strategy of trading agents. This was done in the context of the Reverse TAC, or CAT, game of the Trading Agent Competition. In this game, a set of trading agents, buyers or sellers, are provided by the server and they trade their goods in one of the markets operated by the competing agents. Better knowledge of the strategy of the trading agents will allow a market maker to adapt its incentives and attract more agents to its own market. Our prediction was based on the time series of the traders’ past bids, taking into account the variation of each bid compared to its history. The results proved to be of satisfactory accuracy, both in the game’s context and when compared to other existing approaches.

[Identification of the patient with acute severe pancreatitis. A prospective, comparative study of the Ranson and the Salvador Zubirán National Institute of Nutrition criteria].

PubMed

Uscanga-Domínguez, L F; Herrera-Asencio, E; Enriquez, J R; Vargas-Vorackova, F; Robles-Díaz, G

1998-01-01

Early detection of severe acute pancreatitis could represent a formidable task for the clinician with limited resources. We have previously proposed a series of parameters that can identify patients with severe acute pancreatitis. The aim of this prospective study was to compare Ranson criteria with those previously described by the authors (INNSZ criteria) in 78 patients with acute pancreatitis. Sensitivity, specificity, positive and negative predictive values and accuracy were similar in both scores. We found a good correlation (r = 0.65, p < 0.001) and agreement (z = 5.0, Kappa 0.69, p < 0.001) between Ranson and INNSZ criteria. Our results allow us to propose INNSZ severity criteria as an easy and inexpensive alternative in the evaluation of patients with acute pancreatitis.

Reproducible segmentation of white matter hyperintensities using a new statistical definition.

PubMed

Damangir, Soheil; Westman, Eric; Simmons, Andrew; Vrenken, Hugo; Wahlund, Lars-Olof; Spulber, Gabriela

2017-06-01

We present a method based on a proposed statistical definition of white matter hyperintensities (WMH), which can work with any combination of conventional magnetic resonance (MR) sequences without depending on manually delineated samples. T1-weighted, T2-weighted, FLAIR, and PD sequences acquired at 1.5 Tesla from 119 subjects from the Kings Health Partners-Dementia Case Register (healthy controls, mild cognitive impairment, Alzheimer's disease) were used. The segmentation was performed using a proposed definition for WMH based on the one-tailed Kolmogorov-Smirnov test. The presented method was verified, given all possible combinations of input sequences, against manual segmentations and a high similarity (Dice 0.85-0.91) was observed. Comparing segmentations with different input sequences to one another also yielded a high similarity (Dice 0.83-0.94) that exceeded intra-rater similarity (Dice 0.75-0.91). We compared the results with those of other available methods and showed that the segmentation based on the proposed definition has better accuracy and reproducibility in the test dataset used. Overall, the presented definition is shown to produce accurate results with higher reproducibility than manual delineation. This approach can be an alternative to other manual or automatic methods not only because of its accuracy, but also due to its good reproducibility.

Validation of automatic segmentation of ribs for NTCP modeling.

PubMed

Stam, Barbara; Peulen, Heike; Rossi, Maddalena M G; Belderbos, José S A; Sonke, Jan-Jakob

2016-03-01

Determination of a dose-effect relation for rib fractures in a large patient group has been limited by the time consuming manual delineation of ribs. Automatic segmentation could facilitate such an analysis. We determine the accuracy of automatic rib segmentation in the context of normal tissue complication probability modeling (NTCP). Forty-one patients with stage I/II non-small cell lung cancer treated with SBRT to 54 Gy in 3 fractions were selected. Using the 4DCT derived mid-ventilation planning CT, all ribs were manually contoured and automatically segmented. Accuracy of segmentation was assessed using volumetric, shape and dosimetric measures. Manual and automatic dosimetric parameters Dx and EUD were tested for equivalence using the Two One-Sided T-test (TOST), and assessed for agreement using Bland-Altman analysis. NTCP models based on manual and automatic segmentation were compared. Automatic segmentation was comparable with the manual delineation in radial direction, but larger near the costal cartilage and vertebrae. Manual and automatic Dx and EUD were significantly equivalent. The Bland-Altman analysis showed good agreement. The two NTCP models were very similar. Automatic rib segmentation was significantly equivalent to manual delineation and can be used for NTCP modeling in a large patient group. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Regression analysis and transfer function in estimating the parameters of central pulse waves from brachial pulse wave.

PubMed

Chai Rui; Li Si-Man; Xu Li-Sheng; Yao Yang; Hao Li-Ling

2017-07-01

This study mainly analyzed the parameters such as ascending branch slope (A_slope), dicrotic notch height (Hn), diastolic area (Ad) and systolic area (As) diastolic blood pressure (DBP), systolic blood pressure (SBP), pulse pressure (PP), subendocardial viability ratio (SEVR), waveform parameter (k), stroke volume (SV), cardiac output (CO) and peripheral resistance (RS) of central pulse wave invasively and non-invasively measured. These parameters extracted from the central pulse wave invasively measured were compared with the parameters measured from the brachial pulse waves by a regression model and a transfer function model. The accuracy of the parameters which were estimated by the regression model and the transfer function model was compared too. Our findings showed that in addition to the k value, the above parameters of the central pulse wave and the brachial pulse wave invasively measured had positive correlation. Both the regression model parameters including A_slope, DBP, SEVR and the transfer function model parameters had good consistency with the parameters invasively measured, and they had the same effect of consistency. The regression equations of the three parameters were expressed by Y'=a+bx. The SBP, PP, SV, CO of central pulse wave could be calculated through the regression model, but their accuracies were worse than that of transfer function model.

Inversion of oceanic constituents in case I and II waters with genetic programming algorithms.

PubMed

Chami, Malik; Robilliard, Denis

2002-10-20

A stochastic inverse technique based on agenetic programming (GP) algorithm was developed toinvert oceanic constituents from simulated data for case I and case II water applications. The simulations were carried out with the Ordre Successifs Ocean Atmosphere (OSOA) radiative transfer model. They include the effects of oceanic substances such as algal-related chlorophyll, nonchlorophyllous suspended matter, and dissolved organic matter. The synthetic data set also takes into account the directional effects of particles through a variation of their phase function that makes the simulated data realistic. It is shown that GP can be successfully applied to the inverse problem with acceptable stability in the presence of realistic noise in the data. GP is compared with neural network methodology for case I waters; GP exhibits similar retrieval accuracy, which is greater than for traditional techniques such as band ratio algorithms. The application of GP to real satellite data [a Sea-viewing Wide Field-of-view Sensor (SeaWiFS)] was also carried out for case I waters as a validation. Good agreement was obtained when GP results were compared with the SeaWiFS empirical algorithm. For case II waters the accuracy of GP is less than 33%, which remains satisfactory, at the present time, for remote-sensing purposes.

Establishing a method of short-term rainfall forecasting based on GNSS-derived PWV and its application.

PubMed

Yao, Yibin; Shan, Lulu; Zhao, Qingzhi

2017-09-29

Global Navigation Satellite System (GNSS) can effectively retrieve precipitable water vapor (PWV) with high precision and high-temporal resolution. GNSS-derived PWV can be used to reflect water vapor variation in the process of strong convection weather. By studying the relationship between time-varying PWV and rainfall, it can be found that PWV contents increase sharply before raining. Therefore, a short-term rainfall forecasting method is proposed based on GNSS-derived PWV. Then the method is validated using hourly GNSS-PWV data from Zhejiang Continuously Operating Reference Station (CORS) network of the period 1 September 2014 to 31 August 2015 and its corresponding hourly rainfall information. The results show that the forecasted correct rate can reach about 80%, while the false alarm rate is about 66%. Compared with results of the previous studies, the correct rate is improved by about 7%, and the false alarm rate is comparable. The method is also applied to other three actual rainfall events of different regions, different durations, and different types. The results show that the method has good applicability and high accuracy, which can be used for rainfall forecasting, and in the future study, it can be assimilated with traditional weather forecasting techniques to improve the forecasted accuracy.

Comparisons of the NASA ER-2 meteorological measurement system with radar tracking and radiosonde data

NASA Technical Reports Server (NTRS)

Gaines, Steven E.; Bowen, Stuart W.; Hipskind, R. S.; Bui, T. P.; Chan, K. R.

1992-01-01

Measurements of aircraft longitude, latitude, and velocity, and measurements of atmospheric pressure, temperature, and horizontal wind from the meteorological measurement system (MMS) on board the NASA ER-2 aircraft were compared with independent measurements of these quantities from radiosondes and radar tracking of both the ER-2 and radiosonde balloons. In general, the comparisons were good and within the expected measurement accuracy and natural variability of the meteorological parameters. Radar tracking of the ER-2 resolved the velocity and position drift of the inertial navigation system (INS). The rms errors in the horizontal velocity components of the ER-2, due to INS errors, were found to be 0.5 m/s. The magnitude of the drift in longitude and latitude depends on the sign and magnitude of the corresponding component velocity drift and can be a few hundredths of a degree. The radar altitudes of the ER-2 and radiosondes were used as the basis for comparing measurements of atmospheric pressure, temperature, and horizontal wind from these two platforms. The uncertainty in the MMS horizontal wind measurement is estimated to be +/- 2.5 m/s. The accuracy of the MMS pressure and temperature measurements were inferred to be +/- 0.3 hPa and +/- 0.3 K.

Comparative Performance of Reagents and Platforms for Quantitation of Cytomegalovirus DNA by Digital PCR

PubMed Central

Gu, Z.; Sam, S. S.; Sun, Y.; Tang, L.; Pounds, S.; Caliendo, A. M.

2016-01-01

A potential benefit of digital PCR is a reduction in result variability across assays and platforms. Three sets of PCR reagents were tested on two digital PCR systems (Bio-Rad and RainDance), using three different sets of PCR reagents for quantitation of cytomegalovirus (CMV). Both commercial quantitative viral standards and 16 patient samples (n = 16) were tested. Quantitative accuracy (compared to nominal values) and variability were determined based on viral standard testing results. Quantitative correlation and variability were assessed with pairwise comparisons across all reagent-platform combinations for clinical plasma sample results. The three reagent sets, when used to assay quantitative standards on the Bio-Rad system, all showed a high degree of accuracy, low variability, and close agreement with one another. When used on the RainDance system, one of the three reagent sets appeared to have a much better correlation to nominal values than did the other two. Quantitative results for patient samples showed good correlation in most pairwise comparisons, with some showing poorer correlations when testing samples with low viral loads. Digital PCR is a robust method for measuring CMV viral load. Some degree of result variation may be seen, depending on platform and reagents used; this variation appears to be greater in samples with low viral load values. PMID:27535685

Prediction of Tubal Ectopic Pregnancy Using Offline Analysis of 3-Dimensional Transvaginal Ultrasonographic Data Sets: An Interobserver and Diagnostic Accuracy Study.

PubMed

Infante, Fernando; Espada Vaquero, Mercedes; Bignardi, Tommaso; Lu, Chuan; Testa, Antonia C; Fauchon, David; Epstein, Elisabeth; Leone, Francesco P G; Van den Bosch, Thierry; Martins, Wellington P; Condous, George

2018-06-01

To assess interobserver reproducibility in detecting tubal ectopic pregnancies by reading data sets from 3-dimensional (3D) transvaginal ultrasonography (TVUS) and comparing it with real-time 2-dimensional (2D) TVUS. Images were initially classified as showing pregnancies of unknown location or tubal ectopic pregnancies on real time 2D TVUS by an experienced sonologist, who acquired 5 3D volumes. Data sets were analyzed offline by 5 observers who had to classify each case as ectopic pregnancy or pregnancy of unknown location. The interobserver reproducibility was evaluated by the Fleiss κ statistic. The performance of each observer in predicting ectopic pregnancies was compared to that of the experienced sonologist. Women were followed until they were reclassified as follows: (1) failed pregnancy of unknown location; (2) intrauterine pregnancy; (3) ectopic pregnancy; or (4) persistent pregnancy of unknown location. Sixty-one women were included. The agreement between reading offline 3D data sets and the first real-time 2D TVUS was very good (80%-82%; κ = 0.89). The overall interobserver agreement among observers reading offline 3D data sets was moderate (κ = 0.52). The diagnostic performance of experienced observers reading offline 3D data sets had accuracy of 78.3% to 85.0%, sensitivity of 66.7% to 81.3%, specificity of 79.5% to 88.4%, positive predictive value of 57.1% to 72.2%, and negative predictive value of 87.5% to 91.3%, compared to the experienced sonologist's real-time 2D TVUS: accuracy of 94.5%, sensitivity of 94.4%, specificity of 94.5%, positive predictive value of 85.0%, and negative predictive value of 98.1%. The diagnostic accuracy of 3D TVUS by reading offline data sets for predicting ectopic pregnancies is dependent on experience. Reading only static 3D data sets without clinical information does not match the diagnostic performance of real time 2D TVUS combined with clinical information obtained during the scan. © 2017 by the American Institute of Ultrasound in Medicine.

Highly accurate detection of ovarian cancer using CA125 but limited improvement with serum matrix-assisted laser desorption/ionization time-of-flight mass spectrometry profiling.

PubMed

Tiss, Ali; Timms, John F; Smith, Celia; Devetyarov, Dmitry; Gentry-Maharaj, Aleksandra; Camuzeaux, Stephane; Burford, Brian; Nouretdinov, Ilia; Ford, Jeremy; Luo, Zhiyuan; Jacobs, Ian; Menon, Usha; Gammerman, Alex; Cramer, Rainer

2010-12-01

Our objective was to test the performance of CA125 in classifying serum samples from a cohort of malignant and benign ovarian cancers and age-matched healthy controls and to assess whether combining information from matrix-assisted laser desorption/ionization (MALDI) time-of-flight profiling could improve diagnostic performance. Serum samples from women with ovarian neoplasms and healthy volunteers were subjected to CA125 assay and MALDI time-of-flight mass spectrometry (MS) profiling. Models were built from training data sets using discriminatory MALDI MS peaks in combination with CA125 values and tested their ability to classify blinded test samples. These were compared with models using CA125 threshold levels from 193 patients with ovarian cancer, 290 with benign neoplasm, and 2236 postmenopausal healthy controls. Using a CA125 cutoff of 30 U/mL, an overall sensitivity of 94.8% (96.6% specificity) was obtained when comparing malignancies versus healthy postmenopausal controls, whereas a cutoff of 65 U/mL provided a sensitivity of 83.9% (99.6% specificity). High classification accuracies were obtained for early-stage cancers (93.5% sensitivity). Reasons for high accuracies include recruitment bias, restriction to postmenopausal women, and inclusion of only primary invasive epithelial ovarian cancer cases. The combination of MS profiling information with CA125 did not significantly improve the specificity/accuracy compared with classifications on the basis of CA125 alone. We report unexpectedly good performance of serum CA125 using threshold classification in discriminating healthy controls and women with benign masses from those with invasive ovarian cancer. This highlights the dependence of diagnostic tests on the characteristics of the study population and the crucial need for authors to provide sufficient relevant details to allow comparison. Our study also shows that MS profiling information adds little to diagnostic accuracy. This finding is in contrast with other reports and shows the limitations of serum MS profiling for biomarker discovery and as a diagnostic tool.

Comparative effectiveness of 18F-FDG PET-CT and contrast-enhanced CT in the diagnosis of suspected large-vessel vasculitis.

PubMed

Vaidyanathan, Sriram; Chattopadhyay, Arpita; Mackie, Sarah L; Scarsbrook, Andrew

2018-06-21

Large-vessel vasculitis (LVV) is a serious illness with potentially life-threatening consequences. 18 F-FDG PET-CT has emerged as a valuable diagnostic tool in suspected LVV, combining the strengths of functional and structural imaging. This study aimed to compare the accuracy of FDG PET-CT and contrast-enhanced CT (CECT) in the evaluation of patients with LVV. A retrospective database review for LVV patients undergoing CECT and PET-CT between 2011 to 2016 yielded demographics, scan interval and vasculitis type. Qualitative and quantitative PET-CT analyses included aorta: liver FDG uptake, bespoke FDG uptake distribution scores and vascular maximum standardized uptake values (SUVmax). Quantitative CECT data were assessed wall thickness and mural/lumen ratio. ROC curves were constructed to evaluate comparative diagnostic accuracy and a correlational analysis was conducted between SUVmax and wall-thickness. 36 adults (17 LVV, 19 controls) with a mean age (range) 63 (38-89) years, of which 17 (47%) were males were included. Time interval between CT and PET was mean (standard deviation (SD)) 1.9 (1.2) months. Both SUVmax and wall-thickness demonstrated a significant difference between LVV and controls, with a mean difference (95%confidence interval (CI)) for SUVmax 1.6 (1.1, 2.0) and wall thickness 1.25 (0.68, 1.83) mm, respectively. These two parameters were significantly correlated (p < .0001, R = 0.62). The area under the curve (AUC) (95% CI) for SUVmax was 0.95 (0.88-1.00), and for mural thickening was 0.83 (0.66-0.99). FDG PET-CT demonstrated excellent accuracy whilst CECT mural thickening showed good accuracy in the diagnosis of LVV. Both parameters showed a highly significant correlation. In hospitals without access to FDG PET-CT or in patients unsuitable for PET-CT (e.g., uncontrolled diabetes) CECT offers a viable alternative for the assessment LVV. Advances in knowledge: FDG PET-CT is a highly accurate test for the diagnosis of LVV. Aorta:liver SUVmax ratio is the most specific parameter for LVV. In hospitals without PET-CT or in unsuitable patients e.g. diabetics, CECT is a viable alternative.

Reproducibility of serum IgE, Ara h2 skin prick testing and fraction of exhaled nitric oxide for predicting clinical peanut allergy in children.

PubMed

Percival, Elizabeth; Bhatia, Rani; Preece, Kahn; McElduff, Patrick; McEvoy, Mark; Collison, Adam; Mattes, Joerg

2016-01-01

Ara h2 sIgE serum levels improve the diagnostic accuracy for predicting peanut allergy, but the use of Ara h2 purified protein as a skin prick test (SPT), has not been substantially evaluated. The fraction of exhaled nitric oxide (FeNO) shows promise as a novel biomarker of peanut allergy. Reproducibility of these measures has not been determined. The aim was to assess the accuracy and reproducibility (over a time-period of at least 12 months) of SPT to Ara h2 in comparison with four predictors of clinical peanut allergy (Peanut SPT, Ara h2 specific Immunoglobulin E (sIgE), Peanut sIgE and FeNO). Twenty-seven children were recruited in a follow-up of a prospective cohort of fifty-six children at least 12 months after an open-labelled peanut food challenge. Their repeat assessment involved a questionnaire, SPT to peanut and Ara h2 purified protein, FeNO and sIgE to peanut and Ara h2 measurements. Ara h2 SPT was no worse in accuracy when compared with peanut SPT, FeNO, Ara h2 sIgE and peanut sIgE (AUC 0.908 compared with 0.887, 0.889, 0.935 and 0.804 respectively) for predicting allergic reaction at previous food challenge. SPT for peanut and Ara h2 demonstrated limited reproducibility (ICC = 0.51 and 0.44); while FeNO demonstrated good reproducibility (ICC = 0.73) and sIgE for peanut and Ara h2 were highly reproducible (ICC = 0.81 and 0.85). In this population, Ara h2 SPT was no worse in accuracy when compared with current testing for the evaluation of clinical peanut allergy, but had-like peanut SPT-poor reproducibility. FeNO, peanut sIgE and Ara h2 sIgE were consistently reproducible despite an interval of at least 12 months between the repeated measurements.

The accuracy of the first response histidine-rich protein2 rapid diagnostic test compared with malaria microscopy for guiding field treatment in an outbreak of falciparum malaria.

PubMed

Ghouth, Abdulla Salim Bin; Nasseb, Faraj Mubarak; Al-Kaldy, Khaled Hussin

2012-01-01

Recent WHO guidelines recommended a universal "test and treat" strategy for malaria mainly by use of the rapid diagnostic test (RDT) in all areas. There are concerns about RDT that use the antigen histidine-rich protein2 (HRP2) to detect Plasmodium falciparum, because infection can persist after effective treatment. The aim of this paper is to describe the accuracy of the first response (HRP2)-RDT compared with malaria microscopy used for guiding the field treatment of patients in an outbreak situation in the Al-Rahabah area in Al-Rydah district in Hadramout/Yemen. An ad hoc cross sectional survey of all febrile patients in the affected area was conducted in May 2011. The field team was developed including the case management group and the entomology group. The group of case management prepared their plan based on "test and treat" strategy by using First Response Malaria Antigen HRP2 rapid diagnostic test for falciparum malaria, artemsinin-based combination therapy (ACT) according to the national policy of anti-malaria drugs in Yemen were supplied to treat those who were found to be RDT positive in the field; also blood smear films were taken from every patient with fever in order to validate the use of the RDT in the field. Blood film slides prepared and read by skilled lab technicians, the fourth reading was done by one lab expert in the malaria referral lab. The accuracy parameters of HRP2 compared with microscopy are: Sensitivity (74%), specificity (94%). The positive predictive value is 68% and the negative predictive value is 96%. Total agreement is 148/162 (93%) and the overall prevalence is 14%. All the positive malaria cases were of P. falciparum either coming from RDT or microscopy. HRP2-rapid test is an acceptable test as a guide for field treatment in an outbreak situation where prompt response is indicated. Good prepared blood film slides should be used as it is feasible to evaluate the accuracy of RDTs as a quality control tool.

Estimation of Center of Mass Trajectory using Wearable Sensors during Golf Swing

PubMed Central

Najafi, Bijan; Lee-Eng, Jacqueline; Wrobel, James S.; Goebel, Ruben

2015-01-01

This study suggests a wearable sensor technology to estimate center of mass (CoM) trajectory during a golf swing. Groups of 3, 4, and 18 participants were recruited, respectively, for the purpose of three validation studies. Study 1 examined the accuracy of the system to estimate a 3D body segment angle compared to a camera-based motion analyzer (Vicon®). Study 2 assessed the accuracy of three simplified CoM trajectory models. Finally, Study 3 assessed the accuracy of the proposed CoM model during multiple golf swings. A relatively high agreement was observed between wearable sensors and the reference (Vicon®) for angle measurement (r > 0.99, random error <1.2° (1.5%) for anterior-posterior; <0.9° (2%) for medial-lateral; and <3.6° (2.5%) for internal-external direction). The two-link model yielded a better agreement with the reference system compared to one-link model (r > 0.93 v. r = 0.52, respectively). On the same note, the proposed two-link model estimated CoM trajectory during golf swing with relatively good accuracy (r > 0.9, A-P random error <1cm (7.7%) and <2cm (10.4%) for M-L). The proposed system appears to accurately quantify the kinematics of CoM trajectory as a surrogate of dynamic postural control during an athlete’s movement and its portability, makes it feasible to fit the competitive environment without restricting surface type. Key points This study demonstrates that wearable technology based on inertial sensors are accurate to estimate center of mass trajectory in complex athletic task (e.g., golf swing) This study suggests that two-link model of human body provides optimum tradeoff between accuracy and minimum number of sensor module for estimation of center of mass trajectory in particular during fast movements. Wearable technologies based on inertial sensors are viable option for assessing dynamic postural control in complex task outside of gait laboratory and constraints of cameras, surface, and base of support. PMID:25983585

SU-E-T-13: A Feasibility Study of the Use of Hybrid Computational Phantoms for Improved Historical Dose Reconstruction in the Study of Late Radiation Effects for Hodgkin's Lymphoma

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

Petroccia, H; O'Reilly, S; Bolch, W

Purpose: Radiation-induced cancer effects are well-documented following radiotherapy. Further investigation is needed to more accurately determine a dose-response relationship for late radiation effects. Recent dosimetry studies tend to use representative patients (Taylor 2009) or anthropomorphic phantoms (Wirth 2008) for estimating organ mean doses. In this study, we compare hybrid computational phantoms to patient-specific voxel phantoms to test the accuracy of University of Florida Hybrid Phantom Library (UFHP Library) for historical dose reconstructions. Methods: A cohort of 10 patients with CT images was used to reproduce the data that was collected historically for Hodgkin's lymphoma patients (i.e. caliper measurements and photographs).more » Four types of phantoms were generated to show a range of refinement from reference hybrid-computational phantom to patient-specific phantoms. Each patient is matched to a reference phantom from the UFHP Library based on height and weight. The reference phantom is refined in the anterior/posterior direction to create a ‘caliper-scaled phantom’. A photograph is simulated using a surface rendering from segmented CT images. Further refinement in the lateral direction is performed using ratios from a simulated-photograph to create a ‘photograph and caliper-scaled phantom’; breast size and position is visually adjusted. Patient-specific hybrid phantoms, with matched organ volumes, are generated and show the capabilities of the UF Hybrid Phantom Library. Reference, caliper-scaled, photograph and caliper-scaled, and patient-specific hybrid phantoms are compared with patient-specific voxel phantoms to determine the accuracy of the study. Results: Progression from reference phantom to patient specific hybrid shows good agreement with the patient specific voxel phantoms. Each stage of refinement shows an overall trend of improvement in dose accuracy within the study, which suggests that computational phantoms can show improved accuracy in historical dose estimates. Conclusion: Computational hybrid phantoms show promise for improved accuracy within retrospective studies when CTs and other x-ray images are not available.« less

Effect of tropospheric models on derived precipitable water vapor over Southeast Asia

NASA Astrophysics Data System (ADS)

Rahimi, Zhoobin; Mohd Shafri, Helmi Zulhaidi; Othman, Faridah; Norman, Masayu

2017-05-01

An interesting subject in the field of GPS technology is estimating variation of precipitable water vapor (PWV). This estimation can be used as a data source to assess and monitor rapid changes in meteorological conditions. So far, numerous GPS stations are distributed across the world and the number of GPS networks is increasing. Despite these developments, a challenging aspect of estimating PWV through GPS networks is the need of tropospheric parameters such as temperature, pressure, and relative humidity (Liu et al., 2015). To estimate the tropospheric parameters, global pressure temperature (GPT) model developed by Boehm et al. (2007) is widely used in geodetic analysis for GPS observations. To improve the accuracy, Lagler et al. (2013) introduced GPT2 model by adding annual and semi-annual variation effects to GPT model. Furthermore, Boehm et al. (2015) proposed the GPT2 wet (GPT2w) model which uses water vapor pressure to improve the calculations. The global accuracy of GPT2 and GPT2w models has been evaluated by previous researches (Fund et al., 2011; Munekane and Boehm, 2010); however, investigations to assess the accuracy of global tropospheric models in tropical regions such as Southeast Asia is not sufficient. This study tests and examines the accuracy of GPT2w as one of the most recent versions of tropospheric models (Boehm et al., 2015). We developed a new regional model called Malaysian Pressure Temperature (MPT) model, and compared this model with GPT2w model. The compared results at one international GNSS service (IGS) station located in the south of Peninsula Malaysia shows that MPT model has a better performance than GPT2w model to produce PWV during monsoon season. According to the results, MPT has improved the accuracy of estimated pressure and temperature by 30% and 10%, respectively, in comparison with GPT2w model. These results indicate that MPT model can be a good alternative tool in the absence of meteorological sensors at GPS stations in Peninsula Malaysia. Therefore, for GPS-based studies, we recommend MPT model to be used as a complementary tool for the Malaysia Real-Time Kinematic Network to develop a real-time PWV monitoring system.

2D- and 3D-quantitative structure-activity relationship studies for a series of phenazine N,N'-dioxide as antitumour agents.

PubMed

Cunha, Jonathan Da; Lavaggi, María Laura; Abasolo, María Inés; Cerecetto, Hugo; González, Mercedes

2011-12-01

Hypoxic regions of tumours are associated with increased resistance to radiation and chemotherapy. Nevertheless, hypoxia has been used as a tool for specific activation of some antitumour prodrugs, named bioreductive agents. Phenazine dioxides are an example of such bioreductive prodrugs. Our 2D-quantitative structure activity relationship studies established that phenazine dioxides electronic and lipophilic descriptors are related to survival fraction in oxia or in hypoxia. Additionally, statistically significant models, derived by partial least squares, were obtained between survival fraction in oxia and comparative molecular field analysis standard model (r² = 0.755, q² = 0.505 and F = 26.70) or comparative molecular similarity indices analysis-combined steric and electrostatic fields (r² = 0.757, q² = 0.527 and F = 14.93), and survival fraction in hypoxia and comparative molecular field analysis standard model (r² = 0.736, q² = 0.521 and F = 18.63) or comparative molecular similarity indices analysis-hydrogen bond acceptor field (r² = 0.858, q² = 0.737 and F = 27.19). Categorical classification was used for the biological parameter selective cytotoxicity emerging also good models, derived by soft independent modelling of class analogy, with both comparative molecular field analysis standard model (96% of overall classification accuracy) and comparative molecular similarity indices analysis-steric field (92% of overall classification accuracy). 2D- and 3D-quantitative structure-activity relationships models provided important insights into the chemical and structural basis involved in the molecular recognition process of these phenazines as bioreductive agents and should be useful for the design of new structurally related analogues with improved potency. © 2011 John Wiley & Sons A/S.

Localization Algorithm with On-line Path Loss Estimation and Node Selection

PubMed Central

Bel, Albert; Vicario, José López; Seco-Granados, Gonzalo

2011-01-01

RSS-based localization is considered a low-complexity algorithm with respect to other range techniques such as TOA or AOA. The accuracy of RSS methods depends on the suitability of the propagation models used for the actual propagation conditions. In indoor environments, in particular, it is very difficult to obtain a good propagation model. For that reason, we present a cooperative localization algorithm that dynamically estimates the path loss exponent by using RSS measurements. Since the energy consumption is a key point in sensor networks, we propose a node selection mechanism to limit the number of neighbours of a given node that are used for positioning purposes. Moreover, the selection mechanism is also useful to discard bad links that could negatively affect the performance accuracy. As a result, we derive a practical solution tailored to the strict requirements of sensor networks in terms of complexity, size and cost. We present results based on both computer simulations and real experiments with the Crossbow MICA2 motes showing that the proposed scheme offers a good trade-off in terms of position accuracy and energy efficiency. PMID:22163992

Support vector machine incremental learning triggered by wrongly predicted samples

NASA Astrophysics Data System (ADS)

Tang, Ting-long; Guan, Qiu; Wu, Yi-rong

2018-05-01

According to the classic Karush-Kuhn-Tucker (KKT) theorem, at every step of incremental support vector machine (SVM) learning, the newly adding sample which violates the KKT conditions will be a new support vector (SV) and migrate the old samples between SV set and non-support vector (NSV) set, and at the same time the learning model should be updated based on the SVs. However, it is not exactly clear at this moment that which of the old samples would change between SVs and NSVs. Additionally, the learning model will be unnecessarily updated, which will not greatly increase its accuracy but decrease the training speed. Therefore, how to choose the new SVs from old sets during the incremental stages and when to process incremental steps will greatly influence the accuracy and efficiency of incremental SVM learning. In this work, a new algorithm is proposed to select candidate SVs and use the wrongly predicted sample to trigger the incremental processing simultaneously. Experimental results show that the proposed algorithm can achieve good performance with high efficiency, high speed and good accuracy.

The Good Behavior Game with Students in Alternative Educational Environments: Interactions between Reinforcement Criteria and Scoring Accuracy

ERIC Educational Resources Information Center

Sy, Jolene R.; Gratz, Olivia; Donaldson, Jeanne M.

2016-01-01

The good behavior game (GBG) is a class-wide contingency management strategy that involves rewarding teams who engage in low levels of disruptive behavior. The GBG has been found to be effective with neuro-typical individuals from preschool to high school. In Study 1, teachers and experimenters implemented the GBG on alternating days in an…

Adaptation and validation of a commercial head phantom for cranial radiosurgery dosimetry end-to-end audit.

PubMed

Dimitriadis, Alexis; Palmer, Antony L; Thomas, Russell A S; Nisbet, Andrew; Clark, Catharine H

2017-06-01

To adapt and validate an anthropomorphic head phantom for use in a cranial radiosurgery audit. Two bespoke inserts were produced for the phantom: one for providing the target and organ at risk for delineation and the other for performing dose measurements. The inserts were tested to assess their positional accuracy. A basic treatment plan dose verification with an ionization chamber was performed to establish a baseline accuracy for the phantom and beam model. The phantom and inserts were then used to perform dose verification measurements of a radiosurgery plan. The dose was measured with alanine pellets, EBT extended dose film and a plastic scintillation detector (PSD). Both inserts showed reproducible positioning (±0.5 mm) and good positional agreement between them (±0.6 mm). The basic treatment plan measurements showed agreement to the treatment planning system (TPS) within 0.5%. Repeated film measurements showed consistent gamma passing rates with good agreement to the TPS. For 2%-2 mm global gamma, the mean passing rate was 96.7% and the variation in passing rates did not exceed 2.1%. The alanine pellets and PSD showed good agreement with the TPS (-0.1% and 0.3% dose difference in the target) and good agreement with each other (within 1%). The adaptations to the phantom showed acceptable accuracies. The presence of alanine and PSD do not affect film measurements significantly, enabling simultaneous measurements by all three detectors. Advances in knowledge: A novel method for thorough end-to-end test of radiosurgery, with capability to incorporate all steps of the clinical pathway in a time-efficient and reproducible manner, suitable for a national audit.

Accuracy of Oxygen Flow Delivered by Compressed-Gas Cylinders in Hospital and Prehospital Emergency Care.

PubMed

Duprez, Frédéric; Michotte, Jean Bernard; Cuvelier, Gregory; Legrand, Alexandre; Mashayekhi, Sharam; Reychler, Gregory

2018-03-01

Oxygen cylinders are widely used both in hospital and prehospital care. Excessive or inappropriate F IO 2 may be critical for patients with hypercapnia or hypoxia. Moreover, over-oxygenation could be deleterious in ischemic disorders. Supplemental oxygen from oxygen cylinder should therefore be delivered accurately. The aim of this study was to assess the accuracy of oxygen flows for oxygen cylinder in hospital and prehospital care. A prospective trial was conducted to evaluate accuracy of delivered oxygen flows (2, 4, 6, 9 and 12 L/min) for different oxygen cylinder ready for use in different hospital departments. Delivered flows were analyzed randomly using a calibrated thermal mass flow meter. Two types of oxygen cylinder were evaluated: 78 oxygen cylinder with a single-stage regulator and 70 oxygen cylinder with a dual-stage regulator. Delivered flows were compared to the required oxygen flow. The residual pressure value for each oxygen cylinder was considered. A coefficient of variation was calculated to compare the variability of the delivered flow between the two types of oxygen cylinder. The median values of delivered flows were all ≥ 100% of the required flow for single stage (range 100-109%) and < 100% of required flow for dual stage (range 95-97%). The median values of the delivered flow differed between single and dual stage. It was found that single stage is significantly higher than dual stage ( P = .01). At low flow, the dispersion of the measures for single stage was higher than with a high oxygen flow. Delivered flow differences were also found between low and high residual pressures, but only with single stage ( P = .02). The residual pressure for both oxygen cylinders (no. = 148) ranged from 73 to 2,900 pounds per square inch, and no significant difference was observed between the 2 types ( P = .86). The calculated coefficient of variation ranged from 7% (±1%) for dual stage to 8% (±2%) for single stage. This study shows good accuracy of oxygen flow delivered via oxygen cylinders. This accuracy was higher with dual stage. Single stage was also accurate, however, at low flow this accuracy is slightly less. Moreover, with single stage, when residual pressure decreases, the median value of delivered flow decreased. Copyright © 2018 by Daedalus Enterprises.

Noninvasive scoring algorithm to identify significant liver fibrosis among treatment-naive chronic hepatitis C patients.

PubMed

Koller, Tomas; Kollerova, Jana; Huorka, Martin; Meciarova, Iveta; Payer, Juraj

2014-10-01

Staging for liver fibrosis is recommended in the management of hepatitis C as an argument for treatment priority. Our aim was to construct a noninvasive algorithm to predict the significant liver fibrosis (SLF) using common biochemical markers and compare it with some existing models. The study group included 104 consecutive cases; SLF was defined as Ishak fibrosis stage greater than 2. The patient population was assigned randomly to the training and the validation groups of 52 cases each. The training group was used to construct the algorithm from parameters with the best predictive value. Each parameter was assigned a score that was added to the noninvasive fibrosis score (NFS). The accuracy of NFS in predicting SLF was tested in the validation group and compared with APRI, FIB4, and Forns models. Our algorithm used age, alkaline phosphatase, ferritin, APRI, α2 macroglobulin, and insulin and the NFS ranged from -4 to 5. The probability of SLF was 2.6 versus 77.1% in NFS<0 and NFS>0, leaving NFS=0 in a gray zone (29.8% of cases). The area under the receiver operating curve was 0.895 and 0.886, with a specificity, sensitivity, and diagnostic accuracy of 85.1, 92.3, and 87.5% versus 77.8, 100, and 87.9% for the training and the validation group. In comparison, the area under the receiver operating curve for APRI=0.810, FIB4=0.781, and Forns=0.703 with a diagnostic accuracy of 83.9, 72.3, and 62% and gray zone cases in 46.15, 37.5, and 44.2%. We devised an algorithm to calculate the NFS to predict SLF with good accuracy, fewer cases in the gray zone, and a straightforward clinical interpretation. NFS could be used for the initial evaluation of the treatment priority.

Source localization of rhythmic ictal EEG activity: a study of diagnostic accuracy following STARD criteria.

PubMed

Beniczky, Sándor; Lantz, Göran; Rosenzweig, Ivana; Åkeson, Per; Pedersen, Birthe; Pinborg, Lars H; Ziebell, Morten; Jespersen, Bo; Fuglsang-Frederiksen, Anders

2013-10-01

Although precise identification of the seizure-onset zone is an essential element of presurgical evaluation, source localization of ictal electroencephalography (EEG) signals has received little attention. The aim of our study was to estimate the accuracy of source localization of rhythmic ictal EEG activity using a distributed source model. Source localization of rhythmic ictal scalp EEG activity was performed in 42 consecutive cases fulfilling inclusion criteria. The study was designed according to recommendations for studies on diagnostic accuracy (STARD). The initial ictal EEG signals were selected using a standardized method, based on frequency analysis and voltage distribution of the ictal activity. A distributed source model-local autoregressive average (LAURA)-was used for the source localization. Sensitivity, specificity, and measurement of agreement (kappa) were determined based on the reference standard-the consensus conclusion of the multidisciplinary epilepsy surgery team. Predictive values were calculated from the surgical outcome of the operated patients. To estimate the clinical value of the ictal source analysis, we compared the likelihood ratios of concordant and discordant results. Source localization was performed blinded to the clinical data, and before the surgical decision. Reference standard was available for 33 patients. The ictal source localization had a sensitivity of 70% and a specificity of 76%. The mean measurement of agreement (kappa) was 0.61, corresponding to substantial agreement (95% confidence interval (CI) 0.38-0.84). Twenty patients underwent resective surgery. The positive predictive value (PPV) for seizure freedom was 92% and the negative predictive value (NPV) was 43%. The likelihood ratio was nine times higher for the concordant results, as compared with the discordant ones. Source localization of rhythmic ictal activity using a distributed source model (LAURA) for the ictal EEG signals selected with a standardized method is feasible in clinical practice and has a good diagnostic accuracy. Our findings encourage clinical neurophysiologists assessing ictal EEGs to include this method in their armamentarium. Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.

GPU-accelerated Monte Carlo convolution/superposition implementation for dose calculation.

PubMed

Zhou, Bo; Yu, Cedric X; Chen, Danny Z; Hu, X Sharon

2010-11-01

Dose calculation is a key component in radiation treatment planning systems. Its performance and accuracy are crucial to the quality of treatment plans as emerging advanced radiation therapy technologies are exerting ever tighter constraints on dose calculation. A common practice is to choose either a deterministic method such as the convolution/superposition (CS) method for speed or a Monte Carlo (MC) method for accuracy. The goal of this work is to boost the performance of a hybrid Monte Carlo convolution/superposition (MCCS) method by devising a graphics processing unit (GPU) implementation so as to make the method practical for day-to-day usage. Although the MCCS algorithm combines the merits of MC fluence generation and CS fluence transport, it is still not fast enough to be used as a day-to-day planning tool. To alleviate the speed issue of MC algorithms, the authors adopted MCCS as their target method and implemented a GPU-based version. In order to fully utilize the GPU computing power, the MCCS algorithm is modified to match the GPU hardware architecture. The performance of the authors' GPU-based implementation on an Nvidia GTX260 card is compared to a multithreaded software implementation on a quad-core system. A speedup in the range of 6.7-11.4x is observed for the clinical cases used. The less than 2% statistical fluctuation also indicates that the accuracy of the authors' GPU-based implementation is in good agreement with the results from the quad-core CPU implementation. This work shows that GPU is a feasible and cost-efficient solution compared to other alternatives such as using cluster machines or field-programmable gate arrays for satisfying the increasing demands on computation speed and accuracy of dose calculation. But there are also inherent limitations of using GPU for accelerating MC-type applications, which are also analyzed in detail in this article.

Geometric and mechanical evaluation of 3D-printing materials for skull base anatomical education and endoscopic surgery simulation – A first step to create reliable customized simulators

PubMed Central

Zemiti, Nabil; Caravaca Mora, Oscar; Subsol, Gérard; Captier, Guillaume; Lebrun, Renaud; Crampette, Louis; Mondain, Michel; Gilles, Benjamin

2017-01-01

Introduction Endoscopic skull base surgery allows minimal invasive therapy through the nostrils to treat infectious or tumorous diseases. Surgical and anatomical education in this field is limited by the lack of validated training models in terms of geometric and mechanical accuracy. We choose to evaluate several consumer-grade materials to create a patient-specific 3D-printed skull base model for anatomical learning and surgical training. Methods Four 3D-printed consumer-grade materials were compared to human cadaver bone: calcium sulfate hemihydrate (named Multicolor), polyamide, resin and polycarbonate. We compared the geometric accuracy, forces required to break thin walls of materials and forces required during drilling. Results All materials had an acceptable global geometric accuracy (from 0.083mm to 0.203mm of global error). Local accuracy was better in polycarbonate (0.09mm) and polyamide (0.15mm) than in Multicolor (0.90mm) and resin (0.86mm). Resin and polyamide thin walls were not broken at 200N. Forces needed to break Multicolor thin walls were 1.6–3.5 times higher than in bone. For polycarbonate, forces applied were 1.6–2.5 times higher. Polycarbonate had a mode of fracture similar to the cadaver bone. Forces applied on materials during drilling followed a normal distribution except for the polyamide which was melted. Energy spent during drilling was respectively 1.6 and 2.6 times higher on bone than on PC and Multicolor. Conclusion Polycarbonate is a good substitute of human cadaver bone for skull base surgery simulation. Thanks to short lead times and reasonable production costs, patient-specific 3D printed models can be used in clinical practice for pre-operative training, improving patient safety. PMID:29252993

Magnetic Resonance Enterography to Assess Multifocal and Multicentric Bowel Endometriosis.

PubMed

Nyangoh Timoh, Krystel; Stewart, Zelda; Benjoar, Mikhael; Beldjord, Selma; Ballester, Marcos; Bazot, Marc; Thomassin-Naggara, Isabelle; Darai, Emile

To prospectively determine the accuracy of magnetic resonance enterography (MRE) compared with conventional magnetic resonance imaging (MRI) for multifocal (i.e., multiple lesions affecting the same digestive segment) and multicentric (i.e., multiple lesions affecting several digestive segments) bowel endometriosis. A prospective study (Canadian Task Force classification II-2). Tenon University Hospital, Paris, France. Patients with MRI-suspected colorectal endometriosis scheduled for colorectal resection from April 2014 to February 2016 were included. Patients underwent both 1.5-Tesla MRI and MRE as well as laparoscopically assisted and open colorectal resections. The diagnostic performance of MRI and MRE was evaluated for sensitivity, specificity, positive and negative predictive values, accuracy, and positive and negative likelihood ratios (LRs). The interobserver variability of the experienced and junior radiologists was quantified using weighted statistics. Forty-seven patients were included. Twenty-two (46.8%) patients had unifocal lesions, 14 (30%) had multifocal lesions, and 11 (23.4%) had multicentric lesions. The sensitivity, specificity, positive LR, and negative LR for the diagnosis of multifocal lesions were 0.29 (6/21), 1.00 (23/24), 15.36, and 0.71 for MRI and 0.57 (12/21), 0.89 (23/25), 4.95, and 0.58 for MRE. The sensitivity, specificity, positive LR, and negative LR for the diagnosis of multicentric lesions were 0.18 (1/11), 1.00 (1/1), 15, and 0.80 for MRI and 0.46 (5/11), 0.92 (33/36), 5.45, and 0.60 for MRE. Lower accuracies for MRI compared with MRE to diagnose multicentric (p = .01) and multifocal lesions (p = .004) were noted. The interobserver agreement for MRE was good for both multifocality (κ = 0.80) and multicentricity (κ = 0.61). MRE has better accuracy for diagnosing multifocal and multicentric bowel endometriosis than conventional MRI. Copyright © 2018. Published by Elsevier Inc.

A New Family of Compact High Order Coupled Time-Space Unconditionally Stable Vertical Advection Schemes

NASA Astrophysics Data System (ADS)

Lemarié, F.; Debreu, L.

2016-02-01

Recent papers by Shchepetkin (2015) and Lemarié et al. (2015) have emphasized that the time-step of an oceanic model with an Eulerian vertical coordinate and an explicit time-stepping scheme is very often restricted by vertical advection in a few hot spots (i.e. most of the grid points are integrated with small Courant numbers, compared to the Courant-Friedrichs-Lewy (CFL) condition, except just few spots where numerical instability of the explicit scheme occurs first). The consequence is that the numerics for vertical advection must have good stability properties while being robust to changes in Courant number in terms of accuracy. An other constraint for oceanic models is the strict control of numerical mixing imposed by the highly adiabatic nature of the oceanic interior (i.e. mixing must be very small in the vertical direction below the boundary layer). We examine in this talk the possibility of mitigating vertical Courant-Friedrichs-Lewy (CFL) restriction, while avoiding numerical inaccuracies associated with standard implicit advection schemes (i.e. large sensitivity of the solution on Courant number, large phase delay, and possibly excess of numerical damping with unphysical orientation). Most regional oceanic models have been successfully using fourth order compact schemes for vertical advection. In this talk we present a new general framework to derive generic expressions for (one-step) coupled time and space high order compact schemes (see Daru & Tenaud (2004) for a thorough description of coupled time and space schemes). Among other properties, we show that those schemes are unconditionally stable and have very good accuracy properties even for large Courant numbers while having a very reasonable computational cost. To our knowledge no unconditionally stable scheme with such high order accuracy in time and space have been presented so far in the literature. Furthermore, we show how those schemes can be made monotonic without compromising their stability properties.

Novel SVM-based technique to improve rainfall estimation over the Mediterranean region (north of Algeria) using the multispectral MSG SEVIRI imagery

NASA Astrophysics Data System (ADS)

Sehad, Mounir; Lazri, Mourad; Ameur, Soltane

2017-03-01

In this work, a new rainfall estimation technique based on the high spatial and temporal resolution of the Spinning Enhanced Visible and Infra Red Imager (SEVIRI) aboard the Meteosat Second Generation (MSG) is presented. This work proposes efficient scheme rainfall estimation based on two multiclass support vector machine (SVM) algorithms: SVM_D for daytime and SVM_N for night time rainfall estimations. Both SVM models are trained using relevant rainfall parameters based on optical, microphysical and textural cloud proprieties. The cloud parameters are derived from the Spectral channels of the SEVIRI MSG radiometer. The 3-hourly and daily accumulated rainfall are derived from the 15 min-rainfall estimation given by the SVM classifiers for each MSG observation image pixel. The SVMs were trained with ground meteorological radar precipitation scenes recorded from November 2006 to March 2007 over the north of Algeria located in the Mediterranean region. Further, the SVM_D and SVM_N models were used to estimate 3-hourly and daily rainfall using data set gathered from November 2010 to March 2011 over north Algeria. The results were validated against collocated rainfall observed by rain gauge network. Indeed, the statistical scores given by correlation coefficient, bias, root mean square error and mean absolute error, showed good accuracy of rainfall estimates by the present technique. Moreover, rainfall estimates of our technique were compared with two high accuracy rainfall estimates methods based on MSG SEVIRI imagery namely: random forests (RF) based approach and an artificial neural network (ANN) based technique. The findings of the present technique indicate higher correlation coefficient (3-hourly: 0.78; daily: 0.94), and lower mean absolute error and root mean square error values. The results show that the new technique assign 3-hourly and daily rainfall with good and better accuracy than ANN technique and (RF) model.

Secure Fingerprint Identification of High Accuracy

DTIC Science & Technology

2014-01-01

secure ) solution of complexity O(n3) based on Gaussian elimination. When it is applied to biometrics X and Y with mX and mY minutiae, respectively...collections of biometric data in use today include, for example, fingerprint, face, and iris images collected by the US Department of Homeland Security ...work we focus on fingerprint data due to popularity and good accuracy of this type of biometry. We formulate the problem of private, or secure , finger

How Much Press Do You Need to Cover a War?

DTIC Science & Technology

1994-06-17

before they were sent. Journalists , in the end, succumbed to the pressure and reported according to the military’s rules out of respect for American...some good and some bad journalists . True, some reporters just cannot grasp how releasing certain information will aid the enemy or endanger our troops... Reporting Accuracy is a concern of reputable journalists as well as military commanders. But a report lacking accuracy will cost a commander much

LIDAR mapping of ozone-episode dynamics in Paris and intercomparison with spot analyzers Supplementary material available at http://link.springer.de/journals/apb

NASA Astrophysics Data System (ADS)

Thomasson, A.; Geffroy, S.; Frejafon, E.; Weidauer, D.; Fabian, R.; Godet, Y.; Nominé, M.; Ménard, T.; Rairoux, P.; Moeller, D.; Wolf, J. P.

Continuous mapping of an ozone episode in Paris in June 1999 has been performed using a differential absorption lidar system. The 2D ozone concentration vertical maps recorded over 33 h at the Champ de Mars are compiled in a video clip that gives access to local photochemical dynamics with unprecedented precision. The lidar data are compared over the whole period with point monitors located at 0-, 50-, and 300-m altitudes on the Eiffel Tower. Very good agreement is found when spatial resolution, acquisition time, and required concentration accuracy are optimized. Sensitivity to these parameters for successful intercomparison in urban areas is discussed.

Fast methods to numerically integrate the Reynolds equation for gas fluid films

NASA Technical Reports Server (NTRS)

Dimofte, Florin

1992-01-01

The alternating direction implicit (ADI) method is adopted, modified, and applied to the Reynolds equation for thin, gas fluid films. An efficient code is developed to predict both the steady-state and dynamic performance of an aerodynamic journal bearing. An alternative approach is shown for hybrid journal gas bearings by using Liebmann's iterative solution (LIS) for elliptic partial differential equations. The results are compared with known design criteria from experimental data. The developed methods show good accuracy and very short computer running time in comparison with methods based on an inverting of a matrix. The computer codes need a small amount of memory and can be run on either personal computers or on mainframe systems.

Toward an affordable and user-friendly visual motion capture system.

PubMed

Bonnet, V; Sylla, N; Cherubini, A; Gonzáles, A; Azevedo Coste, C; Fraisse, P; Venture, G

2014-01-01

The present study aims at designing and evaluating a low-cost, simple and portable system for arm joint angle estimation during grasping-like motions. The system is based on a single RGB-D camera and three customized markers. The automatically detected and tracked marker positions were used as inputs to an offline inverse kinematic process based on bio-mechanical constraints to reduce noise effect and handle marker occlusion. The method was validated on 4 subjects with different motions. The joint angles were estimated both with the proposed low-cost system and, a stereophotogrammetric system. Comparative analysis shows good accuracy with high correlation coefficient (r= 0.92) and low average RMS error (3.8 deg).

A comparison between families obtained from different proper elements

NASA Technical Reports Server (NTRS)

Zappala, Vincenzo; Cellino, Alberto; Farinella, Paolo

1992-01-01

Using the hierarchical method of family identification developed by Zappala et al., the results coming from the data set of proper elements computed by Williams (about 2100 numbered + about 1200 PLS 2 asteroids) and by Milani and Knezevic (5.7 version, about 4200 asteroids) are compared. Apart from some expected discrepancies due to the different data sets and/or low accuracy of proper elements computed in peculiar dynamical zones, a good agreement was found in several cases. It follows that these high reliability families represent a sample which can be considered independent on the methods used for their proper elements computation. Therefore, they should be considered as the best candidates for detailed physical studies.

One-Dimensional Modelling of Internal Ballistics

NASA Astrophysics Data System (ADS)

Monreal-González, G.; Otón-Martínez, R. A.; Velasco, F. J. S.; García-Cascáles, J. R.; Ramírez-Fernández, F. J.

2017-10-01

A one-dimensional model is introduced in this paper for problems of internal ballistics involving solid propellant combustion. First, the work presents the physical approach and equations adopted. Closure relationships accounting for the physical phenomena taking place during combustion (interfacial friction, interfacial heat transfer, combustion) are deeply discussed. Secondly, the numerical method proposed is presented. Finally, numerical results provided by this code (UXGun) are compared with results of experimental tests and with the outcome from a well-known zero-dimensional code. The model provides successful results in firing tests of artillery guns, predicting with good accuracy the maximum pressure in the chamber and muzzle velocity what highlights its capabilities as prediction/design tool for internal ballistics.

Coulomb energy differences in isobaric multiplets

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

Lenzi, S. M.; Farnea, E.; Bazzacco, D.

2007-02-12

By comparing the excitation energies of analogue states in isobaric multiplets, several nuclear structure properties can be studied as a function of the angular momentum up to high spin states. In particular, the mirror nuclei 35Ar and 35Cl show large differences between the excitation energies of analogue negative-parity states at high spin, confirming the important contribution of the relativistic electromagnetic spin-orbit interaction to the Coulomb energy. The single-particle character of the configuration of these states is reproduced with very good accuracy by shell model calculations in the sd and pf shells valence space. In addition, evidence of isospin mixing ismore » deduced from the El transitions linking positive and negative parity states.« less

Ultraspectral Infrared Measurements from the Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft

NASA Technical Reports Server (NTRS)

Pagano, Thomas

2003-01-01

Aqua measures the Earth's water cycle, energy fluxes, vegetation and temperatures. The Atmospheric Infrared Sounder (AIRS), Advanced Microwave Sounding Unit (AMSU) and Humidity Sounder for Brazil (HSB) were launched on the EOS Aqua spacecraft in May 2002. AIRS has had good radiometric and spectral sensitivity, stability, and accuracy and is suitable for climate studies. Temperature products compare well with radiosondes and models over the limited test range (|LAT| less than 40 degrees). Early trace gas products demonstrate the potential of AIRS. NASA is developing the next generation of hyperspectral IR imagers. JPL is ready to participate with US government agencies and US industry to transfer AIRS technology and science experience.

Photoelastic Analysis of Cracked Thick Walled Cylinders

NASA Astrophysics Data System (ADS)

Pastramă, Ştefan Dan

2017-12-01

In this paper, the experimental determination of the stress intensity factor in thick walled cylinders subject to uniform internal pressure and having longitudinal non-penetrating cracks is presented. Photoelastic measurements were used together with the expressions of the stress field near the crack tip for Mode I crack extension and a specific methodology for stress intensity factor determination. Two types of longitudinal cracks - internal and external - were considered. Four plane models were manufactured and analyzed in a plane polariscope at different values of the applied internal pressure. The values of the normalized stress intensity factor were calculated and the results were compared to those reported by other authors. A good accuracy was noticed, showing the reliability of the experimental procedure.

Oxygen measurement by multimode diode lasers employing gas correlation spectroscopy.

PubMed

Lou, Xiutao; Somesfalean, Gabriel; Chen, Bin; Zhang, Zhiguo

2009-02-10

Multimode diode laser (MDL)-based correlation spectroscopy (COSPEC) was used to measure oxygen in ambient air, thereby employing a diode laser (DL) having an emission spectrum that overlaps the oxygen absorption lines of the A band. A sensitivity of 700 ppm m was achieved with good accuracy (2%) and linearity (R(2)=0.999). For comparison, measurements of ambient oxygen were also performed by tunable DL absorption spectroscopy (TDLAS) technique employing a vertical cavity surface emitting laser. We demonstrate that, despite slightly degraded sensitivity, the MDL-based COSPEC-based oxygen sensor has the advantages of high stability, low cost, ease-of-use, and relaxed requirements in component selection and instrument buildup compared with the TDLAS-based instrument.

Analytical performance of benchtop total reflection X-ray fluorescence instrumentation for multielemental analysis of wine samples

NASA Astrophysics Data System (ADS)

Dalipi, Rogerta; Marguí, Eva; Borgese, Laura; Bilo, Fabjola; Depero, Laura E.

2016-06-01

Recent technological improvements have led to a widespread adoption of benchtop total reflection X-ray fluorescence systems (TXRF) for analysis of liquid samples. However, benchtop TXRF systems usually present limited sensitivity compared with high-scale instrumentation which can restrict its application in some fields. The aim of the present work was to evaluate and compare the analytical capabilities of two TXRF systems, equipped with low power Mo and W target X-ray tubes, for multielemental analysis of wine samples. Using the Mo-TXRF system, the detection limits for most elements were one order of magnitude lower than those attained using the W-TXRF system. For the detection of high Z elements like Cd and Ag, however, W-TXRF remains a very good option due to the possibility of K-Lines detection. Accuracy and precision of the obtained results have been evaluated analyzing spiked real wine samples and comparing the TXRF results with those obtained by inductively coupled plasma emission spectroscopy (ICP-OES). In general, good agreement was obtained between ICP-OES and TXRF results for the analysis of both red and white wine samples except for light elements (i.e., K) which TXRF concentrations were underestimated. However, a further achievement of analytical quality of TXRF results can be achieved if wine analysis is performed after dilution of the sample with de-ionized water.

Pre-clinical validation of a new intra-operative "dual beam Doppler" blood flowmeter in an artificial circuit.

PubMed

Cikirikcioglu, Mustafa; Cikirikcioglu, Y Banu; Khabiri, Ebrahim; Djebaili, M Karim; Kalangos, Afksendiyos; Walpoth, Beat H

2006-01-01

Intra-operative flow measurement during coronary or peripheral bypass operations is helpful for ruling out technical failures and for prediction of complication and patency rates. Preclinical validation of the flowmeters is required in order to rely on the intra-operatively measured results. The aim of this study is to evaluate a new "dual beam Doppler" blood flowmeter before clinical application and to compare it with the established "transit time flow measure-ment" technique in an artificial circuit. Measurements were performed in an experimental flow model using pig blood and pig arteries. Three different flowmeters were used: Quantix OR (dual beam doppler flowmeter), CardioMed (transit time flowmeter), and Transonic (transit time flowmeter). Three validation tests were performed to assess correlation, precision, and repeatability of devices. (1) Correlation and agreement analysis was performed with various flow amounts (10-350 mL/min) (n = 160). (2) Device reproducibility and measurement stability were tested with a constant flow (flow amount = 300 mL/min) (n = 30). (3) A user accuracy test (intra- and inter-observer variability) was performed by 5 different observers with a constant flow (flow amount = 205 mL/min) (n = 75). Time collected true flow was used as a reference method in all steps and all tests were performed in a blind manner. Results are shown as mean values +/- standard deviations. Pear-son's correlation and Bland-Altman plot analyses were used to compare measurements. The mean flow was 167 +/- 98 mL/min for true flow and 162 +/- 94 mL/min, 165 +/- 94 mL/min, and 166 +/- 100 mL/min for Quantix OR, CardioMed, and Transonic, respectively. Correlation coefficients between Quantix OR, Medi-Stim, Transonic, and time collected true flow were over 0.98 (P = .01). Most of the measured results ( > 90%) were between +/- 1.96 SD agreement limits in Bland and Altman plot analysis. All devices showed good results in the reproducibility test. During the user accuracy test, larger variance changes were observed between intra- and inter-observer results with the dual beam Doppler flowmeter compared to the 2 used transit time flowmeters when used for single sided vessel access without stabilization device (available from the manufacturer). All 3 tested flowmeters showed an excellent correlation to the true flow in an artificial circuit and the accuracy of the tested devices was within agreement limits. Reproducibility of all devices was good and linear. The new dual beam Doppler flow measurement technique compares favorably to the classic transit time method. Clinical use may depend on operator, location, and condition, thus more studies may be required to ensure uniform results using the currently available blood flow measurement devices.

An Improved Method of Heterogeneity Compensation for the Convolution / Superposition Algorithm

NASA Astrophysics Data System (ADS)

Jacques, Robert; McNutt, Todd

2014-03-01

Purpose: To improve the accuracy of convolution/superposition (C/S) in heterogeneous material by developing a new algorithm: heterogeneity compensated superposition (HCS). Methods: C/S has proven to be a good estimator of the dose deposited in a homogeneous volume. However, near heterogeneities electron disequilibrium occurs, leading to the faster fall-off and re-buildup of dose. We propose to filter the actual patient density in a position and direction sensitive manner, allowing the dose deposited near interfaces to be increased or decreased relative to C/S. We implemented the effective density function as a multivariate first-order recursive filter and incorporated it into GPU-accelerated, multi-energetic C/S implementation. We compared HCS against C/S using the ICCR 2000 Monte-Carlo accuracy benchmark, 23 similar accuracy benchmarks and 5 patient cases. Results: Multi-energetic HCS increased the dosimetric accuracy for the vast majority of voxels; in many cases near Monte-Carlo results were achieved. We defined the per-voxel error, %|mm, as the minimum of the distance to agreement in mm and the dosimetric percentage error relative to the maximum MC dose. HCS improved the average mean error by 0.79 %|mm for the patient volumes; reducing the average mean error from 1.93 %|mm to 1.14 %|mm. Very low densities (i.e. < 0.1 g / cm3) remained problematic, but may be solvable with a better filter function. Conclusions: HCS improved upon C/S's density scaled heterogeneity correction with a position and direction sensitive density filter. This method significantly improved the accuracy of the GPU based algorithm reaching the accuracy levels of Monte Carlo based methods with performance in a few tenths of seconds per beam. Acknowledgement: Funding for this research was provided by the NSF Cooperative Agreement EEC9731748, Elekta / IMPAC Medical Systems, Inc. and the Johns Hopkins University. James Satterthwaite provided the Monte Carlo benchmark simulations.

Accuracy and Reliability Assessment of CT and MR Perfusion Analysis Software Using a Digital Phantom

PubMed Central

Christensen, Soren; Sasaki, Makoto; Østergaard, Leif; Shirato, Hiroki; Ogasawara, Kuniaki; Wintermark, Max; Warach, Steven

2013-01-01

Purpose: To design a digital phantom data set for computed tomography (CT) perfusion and perfusion-weighted imaging on the basis of the widely accepted tracer kinetic theory in which the true values of cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and tracer arrival delay are known and to evaluate the accuracy and reliability of postprocessing programs using this digital phantom. Materials and Methods: A phantom data set was created by generating concentration-time curves reflecting true values for CBF (2.5–87.5 mL/100 g per minute), CBV (1.0–5.0 mL/100 g), MTT (3.4–24 seconds), and tracer delays (0–3.0 seconds). These curves were embedded in human brain images. The data were analyzed by using 13 algorithms each for CT and magnetic resonance (MR), including five commercial vendors and five academic programs. Accuracy was assessed by using the Pearson correlation coefficient (r) for true values. Delay-, MTT-, or CBV-dependent errors and correlations between time to maximum of residue function (Tmax) were also evaluated. Results: In CT, CBV was generally well reproduced (r > 0.9 in 12 algorithms), but not CBF and MTT (r > 0.9 in seven and four algorithms, respectively). In MR, good correlation (r > 0.9) was observed in one-half of commercial programs, while all academic algorithms showed good correlations for all parameters. Most algorithms had delay-dependent errors, especially for commercial software, as well as CBV dependency for CBF or MTT calculation and MTT dependency for CBV calculation. Correlation was good in Tmax except for one algorithm. Conclusion: The digital phantom readily evaluated the accuracy and characteristics of the CT and MR perfusion analysis software. All commercial programs had delay-induced errors and/or insufficient correlations with true values, while academic programs for MR showed good correlations with true values. © RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12112618/-/DC1 PMID:23220899

Analytical performance, agreement and user-friendliness of six point-of-care testing urine analysers for urinary tract infection in general practice.

PubMed

Schot, Marjolein J C; van Delft, Sanne; Kooijman-Buiting, Antoinette M J; de Wit, Niek J; Hopstaken, Rogier M

2015-05-18

Various point-of-care testing (POCT) urine analysers are commercially available for routine urine analysis in general practice. The present study compares analytical performance, agreement and user-friendliness of six different POCT urine analysers for diagnosing urinary tract infection in general practice. All testing procedures were performed at a diagnostic centre for primary care in the Netherlands. Urine samples were collected at four general practices. Analytical performance and agreement of the POCT analysers regarding nitrite, leucocytes and erythrocytes, with the laboratory reference standard, was the primary outcome measure, and analysed by calculating sensitivity, specificity, positive and negative predictive value, and Cohen's κ coefficient for agreement. Secondary outcome measures were the user-friendliness of the POCT analysers, in addition to other characteristics of the analysers. The following six POCT analysers were evaluated: Uryxxon Relax (Macherey Nagel), Urisys 1100 (Roche), Clinitek Status (Siemens), Aution 11 (Menarini), Aution Micro (Menarini) and Urilyzer (Analyticon). Analytical performance was good for all analysers. Compared with laboratory reference standards, overall agreement was good, but differed per parameter and per analyser. Concerning the nitrite test, the most important test for clinical practice, all but one showed perfect agreement with the laboratory standard. For leucocytes and erythrocytes specificity was high, but sensitivity was considerably lower. Agreement for leucocytes varied between good to very good, and for the erythrocyte test between fair and good. First-time users indicated that the analysers were easy to use. They expected higher productivity and accuracy when using these analysers in daily practice. The overall performance and user-friendliness of all six commercially available POCT urine analysers was sufficient to justify routine use in suspected urinary tract infections in general practice. 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.

Research on effect of rough surface on FMCW laser radar range accuracy

NASA Astrophysics Data System (ADS)

Tao, Huirong

2018-03-01

The non-cooperative targets large scale measurement system based on frequency-modulated continuous-wave (FMCW) laser detection and ranging technology has broad application prospects. It is easy to automate measurement without cooperative targets. However, the complexity and diversity of the surface characteristics of the measured surface directly affects the measurement accuracy. First, the theoretical analysis of range accuracy for a FMCW laser radar was studied, the relationship between surface reflectivity and accuracy was obtained. Then, to verify the effect of surface reflectance for ranging accuracy, a standard tool ball and three standard roughness samples were measured within 7 m to 24 m. The uncertainty of each target was obtained. The results show that the measurement accuracy is found to increase as the surface reflectivity gets larger. Good agreements were obtained between theoretical analysis and measurements from rough surfaces. Otherwise, when the laser spot diameter is smaller than the surface correlation length, a multi-point averaged measurement can reduce the measurement uncertainty. The experimental results show that this method is feasible.

Optimizing Tsunami Forecast Model Accuracy

NASA Astrophysics Data System (ADS)

Whitmore, P.; Nyland, D. L.; Huang, P. Y.

2015-12-01

Recent tsunamis provide a means to determine the accuracy that can be expected of real-time tsunami forecast models. Forecast accuracy using two different tsunami forecast models are compared for seven events since 2006 based on both real-time application and optimized, after-the-fact "forecasts". Lessons learned by comparing the forecast accuracy determined during an event to modified applications of the models after-the-fact provide improved methods for real-time forecasting for future events. Variables such as source definition, data assimilation, and model scaling factors are examined to optimize forecast accuracy. Forecast accuracy is also compared for direct forward modeling based on earthquake source parameters versus accuracy obtained by assimilating sea level data into the forecast model. Results show that including assimilated sea level data into the models increases accuracy by approximately 15% for the events examined.

Multistix 10 SG Leukocyte Esterage Dipstick Testing in Rapid Bedside Diagnosis of Spontaneous Bacterial Peritonitis: A Prospective Study.

PubMed

Jha, Ashish K; Kumawat, Dal C; Bolya, Yasvant K; Goenka, Mahesh K

2012-09-01

Spontaneous bacterial peritonitis (SBP) requires rapid diagnosis and the initiation of antibiotics. Diagnosis of SBP is usually based on cytobacteriological examination of ascitic fluid. These tests require good laboratory facilities and reporting time of few hours to 1-2 day. However, the 24 h laboratory facilities not widely available in country like India. We evaluated the diagnostic utility of reagent strip (Multistix 10 SG(®)) for rapid diagnosis of SBP. The study was prospectively carried out on patients of cirrhosis with ascites. Bedside leukocyte esterase reagent strip testing was performed on ascitic fluid. Cell count as determined by colorimetric scale of reagent strip was compared with counting chamber method. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated. Out of 100 patients with cirrhotic ascites, [72 males: 28 female; mean age 44.34 (SD 13.03) years] 18 patients were diagnosed to have SBP by counting chamber method as compared to 14 patients detected to have SBP by reagent strip test ≥++ positive. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of reagent strip ≥++ positive were 77.77%, 95.12%, 77.77%, 95.12% and 92% respectively compared to counting chamber method. Reagent strip to diagnose SBP is very specific but less sensitive as compared to counting chamber method. This can be performed rapidly, easily and efficiently even in remote area of developing countries. This bedside test could be a useful tool for the diagnosis of SBP in country like India.

Use of APACHE II and SAPS II to predict mortality for hemorrhagic and ischemic stroke patients.

PubMed

Moon, Byeong Hoo; Park, Sang Kyu; Jang, Dong Kyu; Jang, Kyoung Sool; Kim, Jong Tae; Han, Yong Min

2015-01-01

We studied the applicability of the Acute Physiology and Chronic Health Evaluation II (APACHE II) and Simplified Acute Physiology Score II (SAPS II) in patients admitted to the intensive care unit (ICU) with acute stroke and compared the results with the Glasgow Coma Scale (GCS) and National Institutes of Health Stroke Scale (NIHSS). We also conducted a comparative study of accuracy for predicting hemorrhagic and ischemic stroke mortality. Between January 2011 and December 2012, ischemic or hemorrhagic stroke patients admitted to the ICU were included in the study. APACHE II and SAPS II-predicted mortalities were compared using a calibration curve, the Hosmer-Lemeshow goodness-of-fit test, and the receiver operating characteristic (ROC) curve, and the results were compared with the GCS and NIHSS. Overall 498 patients were included in this study. The observed mortality was 26.3%, whereas APACHE II and SAPS II-predicted mortalities were 35.12% and 35.34%, respectively. The mean GCS and NIHSS scores were 9.43 and 21.63, respectively. The calibration curve was close to the line of perfect prediction. The ROC curve showed a slightly better prediction of mortality for APACHE II in hemorrhagic stroke patients and SAPS II in ischemic stroke patients. The GCS and NIHSS were inferior in predicting mortality in both patient groups. Although both the APACHE II and SAPS II systems can be used to measure performance in the neurosurgical ICU setting, the accuracy of APACHE II in hemorrhagic stroke patients and SAPS II in ischemic stroke patients was superior. Copyright © 2014 Elsevier Ltd. All rights reserved.

In vivo dosimetry with optically stimulated luminescent dosimeters for conformal and intensity-modulated radiation therapy: A 2-year multicenter cohort study.

PubMed

Riegel, Adam C; Chen, Yu; Kapur, Ajay; Apicello, Laura; Kuruvilla, Abraham; Rea, Anthony J; Jamshidi, Abolghassem; Potters, Louis

Optically stimulated luminescent dosimeters (OSLDs) are utilized for in vivo dosimetry (IVD) of modern radiation therapy techniques such as intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT). Dosimetric precision achieved with conventional techniques may not be attainable. In this work, we measured accuracy and precision for a large sample of clinical OSLD-based IVD measurements. Weekly IVD measurements were collected from 4 linear accelerators for 2 years and were expressed as percent differences from planned doses. After outlier analysis, 10,224 measurements were grouped in the following way: overall, modality (photons, electrons), treatment technique (3-dimensional [3D] conformal, field-in-field intensity modulation, inverse-planned IMRT, and VMAT), placement location (gantry angle, cardinality, and central axis positioning), and anatomical site (prostate, breast, head and neck, pelvis, lung, rectum and anus, brain, abdomen, esophagus, and bladder). Distributions were modeled via a Gaussian function. Fitting was performed with least squares, and goodness-of-fit was assessed with the coefficient of determination. Model means (μ) and standard deviations (σ) were calculated. Sample means and variances were compared for statistical significance by analysis of variance and the Levene tests (α = 0.05). Overall, μ ± σ was 0.3 ± 10.3%. Precision for electron measurements (6.9%) was significantly better than for photons (10.5%). Precision varied significantly among treatment techniques (P < .0001) with field-in-field lowest (σ = 7.2%) and IMRT and VMAT highest (σ = 11.9% and 13.4%, respectively). Treatment site models with goodness-of-fit greater than 0.90 (6 of 10) yielded accuracy within ±3%, except for head and neck (μ = -3.7%). Precision varied with treatment site (range, 7.3%-13.0%), with breast and head and neck yielding the best and worst precision, respectively. Placement on the central axis of cardinal gantry angles yielded more precise results (σ = 8.5%) compared with other locations (range, 10.5%-11.4%). Accuracy of ±3% was achievable. Precision ranged from 6.9% to 13.4% depending on modality, technique, and treatment site. Simple, standardized locations may improve IVD precision. These findings may aid development of patient-specific tolerances for OSLD-based IVD. Copyright © 2016 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

Improving the sensitivity and accuracy of gamma activation analysis for the rapid determination of gold in mineral ores.

PubMed

Tickner, James; Ganly, Brianna; Lovric, Bojan; O'Dwyer, Joel

2017-04-01

Mining companies rely on chemical analysis methods to determine concentrations of gold in mineral ore samples. As gold is often mined commercially at concentrations around 1 part-per-million, it is necessary for any analysis method to provide good sensitivity as well as high absolute accuracy. We describe work to improve both the sensitivity and accuracy of the gamma activation analysis (GAA) method for gold. We present analysis results for several suites of ore samples and discuss the design of a GAA facility designed to replace conventional chemical assay in industrial applications. Copyright © 2017. Published by Elsevier Ltd.

Thyroid Carcinoma

PubMed

Ahmed, Najeeb; Niyaz, Kashif; Borakati, Aditya; Marafi, Fahad; Birk, Rubinder; Usmani, Sharjeel

2018-02-26

Differentiated thyroid cancer (DTC) has a good prognosis overall; however, lifelong follow-up is required for many cases. Radioiodine planar imaging with iodine-123 (I-123) or radioiodine-131 (I-131) remains the standard in the follow-up after initial surgery and ablation of residual thyroid tissue using I-131 therapy. Radioiodine imaging is also used in risk-stratifying and for staging of thyroid cancer, and in long-term follow-up. Unfortunately, the lack of anatomical detail on planar gamma camera imaging and superimposition of areas presenting with increased radioiodine uptake can make accurate diagnosis and localization of radioiodine-avid metastatic disease challenging, leading to false positive results and potentially to over-treatment of patients. Hybrid SPECT/CT allows precise anatomical localization and superior characterization of foci of increased tracer uptake when compared to planar imaging. This, in turn, allows the differentiation of pathological and physiological uptake, increasing the accuracy of image interpretation and ultimately improving the accuracy of DTC staging and subsequent patient management. In this review, we look at the unique and emerging role that SPECT/CT plays in the management of DTC, illustrated by examples from our own clinical practice. Creative Commons Attribution License

SU-E-J-89: Deformable Registration Method Using B-TPS in Radiotherapy.

PubMed

Xie, Y

2012-06-01

A novel deformable registration method for four-dimensional computed tomography (4DCT) images is developed in radiation therapy. The proposed method combines the thin plate spline (TPS) and B-spline together to achieve high accuracy and high efficiency. The method consists of two steps. First, TPS is used as a global registration method to deform large unfit regions in the moving image to match counterpart in the reference image. Then B-spline is used for local registration, the previous deformed moving image is further deformed to match the reference image more accurately. Two clinical CT image sets, including one pair of lung and one pair of liver, are simulated using the proposed algorithm, which results in a tremendous improvement in both run-time and registration quality, compared with the conventional methods solely using either TPS or B-spline. The proposed method can combine the efficiency of TPS and the accuracy of B-spline, performing good adaptively and robust in registration of clinical 4DCT image. © 2012 American Association of Physicists in Medicine.

An Effective 3D Shape Descriptor for Object Recognition with RGB-D Sensors

PubMed Central

Liu, Zhong; Zhao, Changchen; Wu, Xingming; Chen, Weihai

2017-01-01

RGB-D sensors have been widely used in various areas of computer vision and graphics. A good descriptor will effectively improve the performance of operation. This article further analyzes the recognition performance of shape features extracted from multi-modality source data using RGB-D sensors. A hybrid shape descriptor is proposed as a representation of objects for recognition. We first extracted five 2D shape features from contour-based images and five 3D shape features over point cloud data to capture the global and local shape characteristics of an object. The recognition performance was tested for category recognition and instance recognition. Experimental results show that the proposed shape descriptor outperforms several common global-to-global shape descriptors and is comparable to some partial-to-global shape descriptors that achieved the best accuracies in category and instance recognition. Contribution of partial features and computational complexity were also analyzed. The results indicate that the proposed shape features are strong cues for object recognition and can be combined with other features to boost accuracy. PMID:28245553

Design and implementation of the modified signed digit multiplication routine on a ternary optical computer.

PubMed

Xu, Qun; Wang, Xianchao; Xu, Chao

2017-06-01

Multiplication with traditional electronic computers is faced with a low calculating accuracy and a long computation time delay. To overcome these problems, the modified signed digit (MSD) multiplication routine is established based on the MSD system and the carry-free adder. Also, its parallel algorithm and optimization techniques are studied in detail. With the help of a ternary optical computer's characteristics, the structured data processor is designed especially for the multiplication routine. Several ternary optical operators are constructed to perform M transformations and summations in parallel, which has accelerated the iterative process of multiplication. In particular, the routine allocates data bits of the ternary optical processor based on digits of multiplication input, so the accuracy of the calculation results can always satisfy the users. Finally, the routine is verified by simulation experiments, and the results are in full compliance with the expectations. Compared with an electronic computer, the MSD multiplication routine is not only good at dealing with large-value data and high-precision arithmetic, but also maintains lower power consumption and fewer calculating delays.

Accuracies and Contrasts of Models of the Diffusion-Weighted-Dependent Attenuation of the MRI Signal at Intermediate b-values.

PubMed

Nicolas, Renaud; Sibon, Igor; Hiba, Bassem

2015-01-01

The diffusion-weighted-dependent attenuation of the MRI signal E(b) is extremely sensitive to microstructural features. The aim of this study was to determine which mathematical model of the E(b) signal most accurately describes it in the brain. The models compared were the monoexponential model, the stretched exponential model, the truncated cumulant expansion (TCE) model, the biexponential model, and the triexponential model. Acquisition was performed with nine b-values up to 2500 s/mm(2) in 12 healthy volunteers. The goodness-of-fit was studied with F-tests and with the Akaike information criterion. Tissue contrasts were differentiated with a multiple comparison corrected nonparametric analysis of variance. F-test showed that the TCE model was better than the biexponential model in gray and white matter. Corrected Akaike information criterion showed that the TCE model has the best accuracy and produced the most reliable contrasts in white matter among all models studied. In conclusion, the TCE model was found to be the best model to infer the microstructural properties of brain tissue.

High accuracy experimental determination of copper and zinc mass attenuation coefficients in the 100 eV to 30 keV photon energy range

NASA Astrophysics Data System (ADS)

Ménesguen, Y.; Gerlach, M.; Pollakowski, B.; Unterumsberger, R.; Haschke, M.; Beckhoff, B.; Lépy, M.-C.

2016-02-01

The knowledge of atomic fundamental parameters such as mass attenuation coefficients with low uncertainties, is of decisive importance in elemental quantification using x-ray fluorescence analysis techniques. Several databases are accessible and frequently used within a large community of users. These compilations are most often in good agreement for photon energies in the hard x-ray ranges. However, they significantly differ for low photon energies and around the absorption edges of any element. In a joint cooperation of the metrology institutes of France and Germany, mass attenuation coefficients of copper and zinc were determined experimentally in the photon energy range from 100 eV to 30 keV by independent approaches using monochromatized synchrotron radiation at SOLEIL (France) and BESSY II (Germany), respectively. The application of high-accuracy experimental techniques resulted in mass attenuation coefficient datasets determined with low uncertainties that are directly compared to existing databases. The novel datasets are expected to enhance the reliability of mass attenuation coefficients.

Fault diagnosis method based on FFT-RPCA-SVM for Cascaded-Multilevel Inverter.

PubMed

Wang, Tianzhen; Qi, Jie; Xu, Hao; Wang, Yide; Liu, Lei; Gao, Diju

2016-01-01

Thanks to reduced switch stress, high quality of load wave, easy packaging and good extensibility, the cascaded H-bridge multilevel inverter is widely used in wind power system. To guarantee stable operation of system, a new fault diagnosis method, based on Fast Fourier Transform (FFT), Relative Principle Component Analysis (RPCA) and Support Vector Machine (SVM), is proposed for H-bridge multilevel inverter. To avoid the influence of load variation on fault diagnosis, the output voltages of the inverter is chosen as the fault characteristic signals. To shorten the time of diagnosis and improve the diagnostic accuracy, the main features of the fault characteristic signals are extracted by FFT. To further reduce the training time of SVM, the feature vector is reduced based on RPCA that can get a lower dimensional feature space. The fault classifier is constructed via SVM. An experimental prototype of the inverter is built to test the proposed method. Compared to other fault diagnosis methods, the experimental results demonstrate the high accuracy and efficiency of the proposed method. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Feature extraction using first and second derivative extrema (FSDE) for real-time and hardware-efficient spike sorting.

PubMed

Paraskevopoulou, Sivylla E; Barsakcioglu, Deren Y; Saberi, Mohammed R; Eftekhar, Amir; Constandinou, Timothy G

2013-04-30

Next generation neural interfaces aspire to achieve real-time multi-channel systems by integrating spike sorting on chip to overcome limitations in communication channel capacity. The feasibility of this approach relies on developing highly efficient algorithms for feature extraction and clustering with the potential of low-power hardware implementation. We are proposing a feature extraction method, not requiring any calibration, based on first and second derivative features of the spike waveform. The accuracy and computational complexity of the proposed method are quantified and compared against commonly used feature extraction methods, through simulation across four datasets (with different single units) at multiple noise levels (ranging from 5 to 20% of the signal amplitude). The average classification error is shown to be below 7% with a computational complexity of 2N-3, where N is the number of sample points of each spike. Overall, this method presents a good trade-off between accuracy and computational complexity and is thus particularly well-suited for hardware-efficient implementation. Copyright © 2013 Elsevier B.V. All rights reserved.

The role of feedback and differences between good and poor decoders in a repeated word reading paradigm in first grade.

PubMed

van Gorp, Karly; Segers, Eliane; Verhoeven, Ludo

2017-04-01

The direct, retention, and transfer effects of repeated word and pseudoword reading were studied in a pretest, training, posttest, retention design. First graders (48 good readers, 47 poor readers) read 25 CVC words and 25 CVC pseudowords in ten repeated word reading sessions, preceded and followed by a transfer task with a different set of items. Two weeks after training, trained items were assessed again in a retention test. Participants either received phonics feedback, in which each word was spelled out and repeated; word feedback, in which each word was repeated; or no feedback. During the training, both good and poor readers improved in accuracy and speed. The increase in speed was stronger for poor readers than for good readers. The good readers demonstrated a stronger increase for pseudowords than for words. This increase in speed was most prominent in the first four sessions. Two weeks after training, the levels of accuracy and speed were retained. Furthermore, transfer effects on speed were found for pseudowords in both groups of readers. Good readers performed most accurately during the training when they received no feedback while poor readers performed most accurately during the training with the help of phonics feedback. However, feedback did not differentiate for reading speed or for effects after the training. The effects of repeated word reading were found to be stronger for poor readers than for good readers. Moreover, these effects were found to be stronger for pseudowords than for words. This indicates that repeated word reading can be seen as an important trigger for the improvement of decoding skills.

Simulation of nitrous oxide effluxes, crop yields and soil physical properties using the LandscapeDNDC model in managed ecosystem

NASA Astrophysics Data System (ADS)

Nyckowiak, Jedrzej; Lesny, Jacek; Haas, Edwin; Juszczak, Radoslaw; Kiese, Ralf; Butterbach-Bahl, Klaus; Olejnik, Janusz

2014-05-01

Modeling of nitrous oxide emissions from soil is very complex. Many different biological and chemical processes take place in soils which determine the amount of emitted nitrous oxide. Additionaly, biogeochemical models contain many detailed factors which may determine fluxes and other simulated variables. We used the LandscapeDNDC model in order to simulate N2O emissions, crop yields and soil physical properties from mineral cultivated soils in Poland. Nitrous oxide emissions from soils were modeled for fields with winter wheat, winter rye, spring barley, triticale, potatoes and alfalfa crops. Simulations were carried out for the plots of the Brody arable experimental station of Poznan University of Life Science in western Poland and covered the period 2003 - 2012. The model accuracy and its efficiency was determined by comparing simulations result with measurements of nitrous oxide emissions (measured with static chambers) from about 40 field campaigns. N2O emissions are strongly dependent on temperature and soil water content, hence we compared also simulated soil temperature at 10cm depth and soil water content at the same depth with the daily measured values of these driving variables. We compared also simulated yield quantities for each individual experimental plots with yield quantities which were measured in the period 2003-2012. We conclude that the LandscapeDNDC model is capable to simulate soil N2O emissions, crop yields and physical properties of soil with satisfactorily good accuracy and efficiency.

Potential of on-line visible and near infrared spectroscopy for measurement of pH for deriving variable rate lime recommendations.

PubMed

Tekin, Yücel; Kuang, Boyan; Mouazen, Abdul M

2013-08-08

This paper aims at exploring the potential of visible and near infrared (vis-NIR) spectroscopy for on-line measurement of soil pH, with the intention to produce variable rate lime recommendation maps. An on-line vis-NIR soil sensor set up to a frame was used in this study. Lime application maps, based on pH predicted by vis-NIR techniques, were compared with maps based on traditional lab-measured pH. The validation of the calibration model using off-line spectra provided excellent prediction accuracy of pH (R2 = 0.85, RMSEP = 0.18 and RPD = 2.52), as compared to very good accuracy obtained with the on-line measured spectra (R2 = 0.81, RMSEP = 0.20 and RPD = 2.14). On-line predicted pH of all points (e.g., 2,160) resulted in the largest overall field virtual lime requirement (1.404 t), as compared to those obtained with 16 validation points off-line prediction (0.28 t), on-line prediction (0.14 t) and laboratory reference measurement (0.48 t). The conclusion is that the vis-NIR spectroscopy can be successfully used for the prediction of soil pH and for deriving lime recommendations. The advantage of the on-line sensor over sampling with limited number of samples is that more detailed information about pH can be obtained, which is the reason for a higher but precise calculated lime recommendation rate.

Potential of On-Line Visible and Near Infrared Spectroscopy for Measurement of pH for Deriving Variable Rate Lime Recommendations

PubMed Central

Tekin, Yücel; Kuang, Boyan; Mouazen, Abdul M.

2013-01-01

This paper aims at exploring the potential of visible and near infrared (vis-NIR) spectroscopy for on-line measurement of soil pH, with the intention to produce variable rate lime recommendation maps. An on-line vis-NIR soil sensor set up to a frame was used in this study. Lime application maps, based on pH predicted by vis-NIR techniques, were compared with maps based on traditional lab-measured pH. The validation of the calibration model using off-line spectra provided excellent prediction accuracy of pH (R2 = 0.85, RMSEP = 0.18 and RPD = 2.52), as compared to very good accuracy obtained with the on-line measured spectra (R2 = 0.81, RMSEP = 0.20 and RPD = 2.14). On-line predicted pH of all points (e.g., 2,160) resulted in the largest overall field virtual lime requirement (1.404 t), as compared to those obtained with 16 validation points off-line prediction (0.28 t), on-line prediction (0.14 t) and laboratory reference measurement (0.48 t). The conclusion is that the vis-NIR spectroscopy can be successfully used for the prediction of soil pH and for deriving lime recommendations. The advantage of the on-line sensor over sampling with limited number of samples is that more detailed information about pH can be obtained, which is the reason for a higher but precise calculated lime recommendation rate. PMID:23966186

A Comparison of Two Balance Calibration Model Building Methods

NASA Technical Reports Server (NTRS)

DeLoach, Richard; Ulbrich, Norbert

2007-01-01

Simulated strain-gage balance calibration data is used to compare the accuracy of two balance calibration model building methods for different noise environments and calibration experiment designs. The first building method obtains a math model for the analysis of balance calibration data after applying a candidate math model search algorithm to the calibration data set. The second building method uses stepwise regression analysis in order to construct a model for the analysis. Four balance calibration data sets were simulated in order to compare the accuracy of the two math model building methods. The simulated data sets were prepared using the traditional One Factor At a Time (OFAT) technique and the Modern Design of Experiments (MDOE) approach. Random and systematic errors were introduced in the simulated calibration data sets in order to study their influence on the math model building methods. Residuals of the fitted calibration responses and other statistical metrics were compared in order to evaluate the calibration models developed with different combinations of noise environment, experiment design, and model building method. Overall, predicted math models and residuals of both math model building methods show very good agreement. Significant differences in model quality were attributable to noise environment, experiment design, and their interaction. Generally, the addition of systematic error significantly degraded the quality of calibration models developed from OFAT data by either method, but MDOE experiment designs were more robust with respect to the introduction of a systematic component of the unexplained variance.

The concurrent validity of the Amharic version of Screening of Activity Limitation and Safety Awareness (SALSA) in persons affected by leprosy.

PubMed

Wijk, Ulrika; Brandsma, J Wim; Dahlström, Orjan; Björk, Mathilda

2013-03-01

Leprosy is endemic in many countries and results in activity limitations. There is a need for assessment tools to guide professionals in their evaluation and choice of intervention in order to improve conditions for leprosy-affected people. The purpose of our study was to evaluate the concurrent validity of the Amharic version of Screening of Activity Limitation and Safety Awareness (SALSA-am) scale with Amharic version of Disability of the Arm, Shoulder and Hand (DASH-am) questionnaire. Thirty-eight individuals with nerve damage due to leprosy completed the SALSA-am and DASH-am questionnaires. Spearman's rank correlation was used to determine relationships between SALSA and DASH scores. Specificity, sensitivity and accuracy were calculated. There was a good correlation 0.87 (P < 0.001) between SALSA-am and DASH-am scores. Sensitivity, specificity and accuracy were calculated with acceptable results. SALSA-am is considered a useful questionnaire for determining activity limitations in persons affected by leprosy, and showed good correlation with DASH-am. The concurrent validity was considered good.

Magnetic Resonance Imaging of Pulmonary Embolism: Diagnostic Accuracy of Unenhanced MR and Influence in Mortality Rates.

PubMed

Pasin, Lilian; Zanon, Matheus; Moreira, Jose; Moreira, Ana Luiza; Watte, Guilherme; Marchiori, Edson; Hochhegger, Bruno

2017-04-01

We evaluated the diagnostic value for pulmonary embolism (PE) of the True fast imaging with steady-state precession (TrueFISP) MRI, a method that allows the visualization of pulmonary vasculature without breath holding or intravenous contrast. This is a prospective investigation including 93 patients with suspected PE. All patients underwent TrueFISP MRI after undergoing CT pulmonary angiography (CTPA). Two independent readers evaluated each MR study, and consensus was obtained. CTPA results were analysed by a third independent reviewer and these results served as the reference standard. A fourth radiologist was responsible for evaluating if lesions found on MRI for both analysis were the same and if these were the correspondent lesions on the CTPA. Sensitivity, specificity, predictive values and accuracy were calculated. Evidence for death from PE within the 1-year follow-up was also assessed. Two patients could not undergo the real-time MRI and were excluded from the study. PE prevalence was 22%. During the 1-year follow-up period, eight patients died, whereas PE was responsible for 12.5% of cases. Between patients who developed PE, only 5% died due to this condition. There were no differences between MR and CT embolism detection in these subjects. MR sequences had a sensitivity of 85%, specificity was 98.6% and accuracy was 95.6%. Agreement between readers was high (κ= 0.87). Compared with contrast-enhanced CT, unenhanced MR sequences demonstrate good accuracy and no differences in the mortality rates in 1 year were detected.

Contention Modeling for Multithreaded Distributed Shared Memory Machines: The Cray XMT

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

Secchi, Simone; Tumeo, Antonino; Villa, Oreste

Distributed Shared Memory (DSM) machines are a wide class of multi-processor computing systems where a large virtually-shared address space is mapped on a network of physically distributed memories. High memory latency and network contention are two of the main factors that limit performance scaling of such architectures. Modern high-performance computing DSM systems have evolved toward exploitation of massive hardware multi-threading and fine-grained memory hashing to tolerate irregular latencies, avoid network hot-spots and enable high scaling. In order to model the performance of such large-scale machines, parallel simulation has been proved to be a promising approach to achieve good accuracy inmore » reasonable times. One of the most critical factors in solving the simulation speed-accuracy trade-off is network modeling. The Cray XMT is a massively multi-threaded supercomputing architecture that belongs to the DSM class, since it implements a globally-shared address space abstraction on top of a physically distributed memory substrate. In this paper, we discuss the development of a contention-aware network model intended to be integrated in a full-system XMT simulator. We start by measuring the effects of network contention in a 128-processor XMT machine and then investigate the trade-off that exists between simulation accuracy and speed, by comparing three network models which operate at different levels of accuracy. The comparison and model validation is performed by executing a string-matching algorithm on the full-system simulator and on the XMT, using three datasets that generate noticeably different contention patterns.« less

Aerial Images and Convolutional Neural Network for Cotton Bloom Detection.

PubMed

Xu, Rui; Li, Changying; Paterson, Andrew H; Jiang, Yu; Sun, Shangpeng; Robertson, Jon S

2017-01-01

Monitoring flower development can provide useful information for production management, estimating yield and selecting specific genotypes of crops. The main goal of this study was to develop a methodology to detect and count cotton flowers, or blooms, using color images acquired by an unmanned aerial system. The aerial images were collected from two test fields in 4 days. A convolutional neural network (CNN) was designed and trained to detect cotton blooms in raw images, and their 3D locations were calculated using the dense point cloud constructed from the aerial images with the structure from motion method. The quality of the dense point cloud was analyzed and plots with poor quality were excluded from data analysis. A constrained clustering algorithm was developed to register the same bloom detected from different images based on the 3D location of the bloom. The accuracy and incompleteness of the dense point cloud were analyzed because they affected the accuracy of the 3D location of the blooms and thus the accuracy of the bloom registration result. The constrained clustering algorithm was validated using simulated data, showing good efficiency and accuracy. The bloom count from the proposed method was comparable with the number counted manually with an error of -4 to 3 blooms for the field with a single plant per plot. However, more plots were underestimated in the field with multiple plants per plot due to hidden blooms that were not captured by the aerial images. The proposed methodology provides a high-throughput method to continuously monitor the flowering progress of cotton.

Genotype Imputation for Latinos Using the HapMap and 1000 Genomes Project Reference Panels.

PubMed

Gao, Xiaoyi; Haritunians, Talin; Marjoram, Paul; McKean-Cowdin, Roberta; Torres, Mina; Taylor, Kent D; Rotter, Jerome I; Gauderman, William J; Varma, Rohit

2012-01-01

Genotype imputation is a vital tool in genome-wide association studies (GWAS) and meta-analyses of multiple GWAS results. Imputation enables researchers to increase genomic coverage and to pool data generated using different genotyping platforms. HapMap samples are often employed as the reference panel. More recently, the 1000 Genomes Project resource is becoming the primary source for reference panels. Multiple GWAS and meta-analyses are targeting Latinos, the most populous, and fastest growing minority group in the US. However, genotype imputation resources for Latinos are rather limited compared to individuals of European ancestry at present, largely because of the lack of good reference data. One choice of reference panel for Latinos is one derived from the population of Mexican individuals in Los Angeles contained in the HapMap Phase 3 project and the 1000 Genomes Project. However, a detailed evaluation of the quality of the imputed genotypes derived from the public reference panels has not yet been reported. Using simulation studies, the Illumina OmniExpress GWAS data from the Los Angles Latino Eye Study and the MACH software package, we evaluated the accuracy of genotype imputation in Latinos. Our results show that the 1000 Genomes Project AMR + CEU + YRI reference panel provides the highest imputation accuracy for Latinos, and that also including Asian samples in the panel can reduce imputation accuracy. We also provide the imputation accuracy for each autosomal chromosome using the 1000 Genomes Project panel for Latinos. Our results serve as a guide to future imputation based analysis in Latinos.

Evaluation of the reliability and accuracy of using cone-beam computed tomography for diagnosing periapical cysts from granulomas.

PubMed

Guo, Jing; Simon, James H; Sedghizadeh, Parish; Soliman, Osman N; Chapman, Travis; Enciso, Reyes

2013-12-01

The purpose of this study was to evaluate the reliability and accuracy of cone-beam computed tomographic (CBCT) imaging against the histopathologic diagnosis for the differential diagnosis of periapical cysts (cavitated lesions) from (solid) granulomas. Thirty-six periapical lesions were imaged using CBCT scans. Apicoectomy surgeries were conducted for histopathological examination. Evaluator 1 examined each CBCT scan for the presence of 6 radiologic characteristics of a cyst (ie, location, periphery, shape, internal structure, effects on surrounding structure, and perforation of the cortical plate). Not every cyst showed all radiologic features (eg, not all cysts perforate the cortical plate). For the purpose of finding the minimum number of diagnostic criteria present in a scan to diagnose a lesion as a cyst, we conducted 6 receiver operating characteristic curve analyses comparing CBCT diagnoses with the histopathologic diagnosis. Two other independent evaluators examined the CBCT lesions. Statistical tests were conducted to examine the accuracy, inter-rater reliability, and intrarater reliability of CBCT images. Findings showed that a score of ≥4 positive findings was the optimal scoring system. The accuracies of differential diagnoses of 3 evaluators were moderate (area under the curve = 0.76, 0.70, and 0.69 for evaluators 1, 2, and 3, respectively). The inter-rater agreement of the 3 evaluators was excellent (α = 0.87). The intrarater agreement was good to excellent (κ = 0.71, 0.76, and 0.77). CBCT images can provide a moderately accurate diagnosis between cysts and granulomas. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

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

Morrison, H; Menon, G; Sloboda, R

The purpose of this study was to investigate the accuracy of radiochromic film calibration procedures used in external beam radiotherapy when applied to I-125 brachytherapy sources delivering higher doses, and to determine any necessary modifications to achieve similar accuracy in absolute dose measurements. GafChromic EBT3 film was used to measure radiation doses upwards of 35 Gy from 6 MV, 75 kVp and (∼28 keV) I-125 photon sources. A custom phantom was used for the I-125 irradiations to obtain a larger film area with nearly constant dose to reduce the effects of film heterogeneities on the optical density (OD) measurements. RGBmore » transmission images were obtained with an Epson 10000XL flatbed scanner, and calibration curves relating OD and dose using a rational function were determined for each colour channel and at each energy using a non-linear least square minimization method. Differences found between the 6 MV calibration curve and those for the lower energy sources are large enough that 6 MV beams should not be used to calibrate film for low-energy sources. However, differences between the 75 kVp and I-125 calibration curves were quite small; indicating that 75 kVp is a good choice. Compared with I-125 irradiation, this gives the advantages of lower type B uncertainties and markedly reduced irradiation time. To obtain high accuracy calibration for the dose range up to 35 Gy, two-segment piece-wise fitting was required. This yielded absolute dose measurement accuracy above 1 Gy of ∼2% for 75 kVp and ∼5% for I-125 seed exposures.« less

Accuracy of dengue clinical diagnosis with and without NS1 antigen rapid test: Comparison between human and Bayesian network model decision.

PubMed

Sa-Ngamuang, Chaitawat; Haddawy, Peter; Luvira, Viravarn; Piyaphanee, Watcharapong; Iamsirithaworn, Sopon; Lawpoolsri, Saranath

2018-06-18

Differentiating dengue patients from other acute febrile illness patients is a great challenge among physicians. Several dengue diagnosis methods are recommended by WHO. The application of specific laboratory tests is still limited due to high cost, lack of equipment, and uncertain validity. Therefore, clinical diagnosis remains a common practice especially in resource limited settings. Bayesian networks have been shown to be a useful tool for diagnostic decision support. This study aimed to construct Bayesian network models using basic demographic, clinical, and laboratory profiles of acute febrile illness patients to diagnose dengue. Data of 397 acute undifferentiated febrile illness patients who visited the fever clinic of the Bangkok Hospital for Tropical Diseases, Thailand, were used for model construction and validation. The two best final models were selected: one with and one without NS1 rapid test result. The diagnostic accuracy of the models was compared with that of physicians on the same set of patients. The Bayesian network models provided good diagnostic accuracy of dengue infection, with ROC AUC of 0.80 and 0.75 for models with and without NS1 rapid test result, respectively. The models had approximately 80% specificity and 70% sensitivity, similar to the diagnostic accuracy of the hospital's fellows in infectious disease. Including information on NS1 rapid test improved the specificity, but reduced the sensitivity, both in model and physician diagnoses. The Bayesian network model developed in this study could be useful to assist physicians in diagnosing dengue, particularly in regions where experienced physicians and laboratory confirmation tests are limited.

Using Markov Chains and Multi-Objective Optimization for Energy-Efficient Context Recognition.

PubMed

Janko, Vito; Luštrek, Mitja

2017-12-29

The recognition of the user's context with wearable sensing systems is a common problem in ubiquitous computing. However, the typically small battery of such systems often makes continuous recognition impractical. The strain on the battery can be reduced if the sensor setting is adapted to each context. We propose a method that efficiently finds near-optimal sensor settings for each context. It uses Markov chains to simulate the behavior of the system in different configurations and the multi-objective genetic algorithm to find a set of good non-dominated configurations. The method was evaluated on three real-life datasets and found good trade-offs between the system's energy expenditure and the system's accuracy. One of the solutions, for example, consumed five-times less energy than the default one, while sacrificing only two percentage points of accuracy.

Reliability and type of consumer health documents on the World Wide Web: an annotation study.

PubMed

Martin, Melanie J

2011-01-01

In this paper we present a detailed scheme for annotating medical web pages designed for health care consumers. The annotation is along two axes: first, by reliability (the extent to which the medical information on the page can be trusted), second, by the type of page (patient leaflet, commercial, link, medical article, testimonial, or support). We analyze inter-rater agreement among three judges for each axis. Inter-rater agreement was moderate (0.77 accuracy, 0.62 F-measure, 0.49 Kappa) on the page reliability axis and good (0.81 accuracy, 0.72 F-measure, 0.73 Kappa) along the page type axis. We have shown promising results in this study that appropriate classes of pages can be developed and used by human annotators to annotate web pages with reasonable to good agreement. No.

Analytical parameters of the microplate-based ORAC-pyrogallol red assay.

PubMed

Ortiz, Rocío; Antilén, Mónica; Speisky, Hernán; Aliaga, Margarita E; López-Alarcón, Camilo

2011-01-01

The analytical parameters of the microplate-based oxygen radicals absorbance capacity (ORAC) method using pyrogallol red (PGR) as probe (ORAC-PGR) are presented. In addition, the antioxidant capacity of commercial beverages, such as wines, fruit juices, and iced teas, is estimated. A good linearity of the area under the curve (AUC) versus Trolox concentration plots was obtained [AUC = (845 +/- 110) + (23 +/- 2) [Trolox, microM], R = 0.9961, n = 19]. QC experiments showed better precision and accuracy at the highest Trolox concentration (40 microM) with RSD and REC (recuperation) values of 1.7 and 101.0%, respectively. When red wine was used as sample, the method also showed good linearity [AUC = (787 +/- 77) + (690 +/- 60) [red wine, microL/mL]; R = 0.9926, n = 17], precision and accuracy with RSD values from 1.4 to 8.3%, and REC values that ranged from 89.7 to 103.8%. Additivity assays using solutions containing gallic acid and Trolox (or red wine) showed an additive protection of PGR given by the samples. Red wines showed higher ORAC-PGR values than white wines, while the ORAC-PGR index of fruit juices and iced teas presented a great variability, ranging from 0.6 to 21.6 mM of Trolox equivalents. This variability was also observed for juices of the same fruit, showing the influence of the brand on the ORAC-PGR index. The ORAC-PGR methodology can be applied in a microplate reader with good linearity, precision, and accuracy.

Recalibrating disease parameters for increasing realism in modeling epidemics in closed settings.

PubMed

Bioglio, Livio; Génois, Mathieu; Vestergaard, Christian L; Poletto, Chiara; Barrat, Alain; Colizza, Vittoria

2016-11-14

The homogeneous mixing assumption is widely adopted in epidemic modelling for its parsimony and represents the building block of more complex approaches, including very detailed agent-based models. The latter assume homogeneous mixing within schools, workplaces and households, mostly for the lack of detailed information on human contact behaviour within these settings. The recent data availability on high-resolution face-to-face interactions makes it now possible to assess the goodness of this simplified scheme in reproducing relevant aspects of the infection dynamics. We consider empirical contact networks gathered in different contexts, as well as synthetic data obtained through realistic models of contacts in structured populations. We perform stochastic spreading simulations on these contact networks and in populations of the same size under a homogeneous mixing hypothesis. We adjust the epidemiological parameters of the latter in order to fit the prevalence curve of the contact epidemic model. We quantify the agreement by comparing epidemic peak times, peak values, and epidemic sizes. Good approximations of the peak times and peak values are obtained with the homogeneous mixing approach, with a median relative difference smaller than 20 % in all cases investigated. Accuracy in reproducing the peak time depends on the setting under study, while for the peak value it is independent of the setting. Recalibration is found to be linear in the epidemic parameters used in the contact data simulations, showing changes across empirical settings but robustness across groups and population sizes. An adequate rescaling of the epidemiological parameters can yield a good agreement between the epidemic curves obtained with a real contact network and a homogeneous mixing approach in a population of the same size. The use of such recalibrated homogeneous mixing approximations would enhance the accuracy and realism of agent-based simulations and limit the intrinsic biases of the homogeneous mixing.

Understanding of diagnosis and medications among non-English-speaking older patients.

PubMed

Teo, Ken Gw; Tacey, Mark; Holbeach, Edwina

2018-01-28

To determine whether non-English-speaking background (NESB) patients had a poorer understanding of diagnosis and medications compared to English-speaking background (ESB) patients. English-speaking background and NESB patients admitted to inpatient geriatric evaluation and management (GEM) unit were asked standardised questions about their admission diagnosis, reason for GEM admission and medications. Accuracy of answers, as compared to medical notes, ranked as 'full credit', 'partial credit' or 'no credit'. Of the 66 patients recruited (30 NESB), understanding of diagnosis and purpose of GEM admission was good. There was no difference between ESB and NESB patients. Understanding of medications taken prior to admission was poor, with 67% of overall patients scoring 'no credit'. NESB patients were more likely to score 'no credit' compared to ESB (80% vs 56%, P = 0.036). Reassuringly, patients had a reasonable understanding of diagnosis and purpose of GEM admission. Lack of understanding of medications, especially among NESB patients, should be improved. © 2018 AJA Inc.

Comparative performance of short-term diffusion barrier charcoal canisters and long-term alpha-track monitors for indoor 222Rn measurements.

PubMed

Martz, D E; George, J L; Langner, G H

1991-04-01

The accuracy and precision of indoor 222Rn measurements obtained with the use of diffusion barrier charcoal canisters (DBCC) under actual field conditions were determined by comparing the integrated average of 26 successive 7-d exposures of DBCC in each of 16 occupied residences over a 6-mo period with simultaneous measurements using four types of commercially available alpha-track monitors (ATM) and one type of scintillation chamber continuous 222Rn monitor. The results suggest that properly calibrated DBCCs provide very good estimates of the integrated 222Rn concentrations in residential structures over the standard 1-wk exposure period despite the occurrence of large diurnal variations in the actual 222Rn concentrations. The results also suggest that a relatively small number of 1-wk DBCC measurements at selected times throughout the calendar year would provide estimates of the annual average indoor 222Rn concentrations that compare favorably with single long-term ATM measurements.

Comparative analysis of diagnostic performance, feasibility and cost of different test-methods for thyroid nodules with indeterminate cytology

PubMed Central

Sciacchitano, Salvatore; Lavra, Luca; Ulivieri, Alessandra; Magi, Fiorenza; De Francesco, Gian Paolo; Bellotti, Carlo; Salehi, Leila B.; Trovato, Maria; Drago, Carlo; Bartolazzi, Armando

2017-01-01

Since it is impossible to recognize malignancy at fine needle aspiration (FNA) cytology in indeterminate thyroid nodules, surgery is recommended for all of them. However, cancer rate at final histology is <30%. Many different test-methods have been proposed to increase diagnostic accuracy in such lesions, including Galectin-3-ICC (GAL-3-ICC), BRAF mutation analysis (BRAF), Gene Expression Classifier (GEC) alone and GEC+BRAF, mutation/fusion (M/F) panel, alone, M/F panel+miRNA GEC, and M/F panel by next generation sequencing (NGS), FDG-PET/CT, MIBI-Scan and TSHR mRNA blood assay. We performed systematic reviews and meta-analyses to compare their features, feasibility, diagnostic performance and cost. GEC, GEC+BRAF, M/F panel+miRNA GEC and M/F panel by NGS were the best in ruling-out malignancy (sensitivity = 90%, 89%, 89% and 90% respectively). BRAF and M/F panel alone and by NGS were the best in ruling-in malignancy (specificity = 100%, 93% and 93%). The M/F by NGS showed the highest accuracy (92%) and BRAF the highest diagnostic odds ratio (DOR) (247). GAL-3-ICC performed well as rule-out (sensitivity = 83%) and rule-in test (specificity = 85%), with good accuracy (84%) and high DOR (27) and is one of the cheapest (113 USD) and easiest one to be performed in different clinical settings. In conclusion, the more accurate molecular-based test-methods are still expensive and restricted to few, highly specialized and centralized laboratories. GAL-3-ICC, although limited by some false negatives, represents the most suitable screening test-method to be applied on a large-scale basis in the diagnostic algorithm of indeterminate thyroid lesions. PMID:28472764

Performance and Accuracy of Lightweight and Low-Cost GPS Data Loggers According to Antenna Positions, Fix Intervals, Habitats and Animal Movements

PubMed Central

Forin-Wiart, Marie-Amélie; Hubert, Pauline; Sirguey, Pascal; Poulle, Marie-Lazarine

2015-01-01

Recently developed low-cost Global Positioning System (GPS) data loggers are promising tools for wildlife research because of their affordability for low-budget projects and ability to simultaneously track a greater number of individuals compared with expensive built-in wildlife GPS. However, the reliability of these devices must be carefully examined because they were not developed to track wildlife. This study aimed to assess the performance and accuracy of commercially available GPS data loggers for the first time using the same methods applied to test built-in wildlife GPS. The effects of antenna position, fix interval and habitat on the fix-success rate (FSR) and location error (LE) of CatLog data loggers were investigated in stationary tests, whereas the effects of animal movements on these errors were investigated in motion tests. The units operated well and presented consistent performance and accuracy over time in stationary tests, and the FSR was good for all antenna positions and fix intervals. However, the LE was affected by the GPS antenna and fix interval. Furthermore, completely or partially obstructed habitats reduced the FSR by up to 80% in households and increased the LE. Movement across habitats had no effect on the FSR, whereas forest habitat influenced the LE. Finally, the mean FSR (0.90 ± 0.26) and LE (15.4 ± 10.1 m) values from low-cost GPS data loggers were comparable to those of built-in wildlife GPS collars (71.6% of fixes with LE < 10 m for motion tests), thus confirming their suitability for use in wildlife studies. PMID:26086958

Factors interfering with the accuracy of five blood glucose meters used in Chinese hospitals.

PubMed

Lv, Hong; Zhang, Guo-jun; Kang, Xi-xiong; Yuan, Hui; Lv, Yan-wei; Wang, Wen-wen; Randall, Rollins

2013-09-01

The prevalence of diabetes is increasing in China. Glucose control is very important in diabetic patients. The aim of this study was to compare the accuracy of five glucose meters used in Chinese hospitals with a reference method, in the absence and presence of various factors that may interfere with the meters. Within-run precision of the meters was evaluated include Roche Accu-Chek Inform®, Abbott Precision PCx FreeStyle®, Bayer Contour®, J&J LifeScan SureStep Flexx®, and Nova Biomedical StatStrip®. The interference of hematocrit level, maltose, ascorbic acid, acetaminophen, galactose, dopamine, and uric acid were tested in three levels of blood glucose, namely low, medium, and high concentrations. Accuracy (bias) of the meters and analytical interference by various factors were evaluated by comparing results obtained in whole blood specimens with those in plasma samples of the whole blood specimens run on the reference method. Impact of oxygen tension on above five blood glucose meters was detected. Precision was acceptable and slightly different between meters. There were no significant differences in the measurements between the meters and the reference method. The hematocrit level significantly interfered with all meters, except StatStrip. Measurements were affected to varying degrees by different substances at different glucose levels, e.g. acetaminophen and ascorbic acid (Freestyle), maltose and galactose (FreeStyle, Accu-Chek), uric acid (FreeStyle, Bayer Contour), and dopamine (Bayer Contour). The measurements with the five meters showed a good correlation with the plasma hexokinase reference method, but most were affected by the hematocrit level. Some meters also showed marked interference by other substances. © 2013 Wiley Periodicals, Inc.

Critically re-evaluating a common technique

PubMed Central

Geisbush, Thomas; Jones, Lyell; Weiss, Michael; Mozaffar, Tahseen; Gronseth, Gary; Rutkove, Seward B.

2016-01-01

Objectives: (1) To assess the diagnostic accuracy of EMG in radiculopathy. (2) To evaluate the intrarater reliability and interrater reliability of EMG in radiculopathy. (3) To assess the presence of confirmation bias in EMG. Methods: Three experienced academic electromyographers interpreted 3 compact discs with 20 EMG videos (10 normal, 10 radiculopathy) in a blinded, standardized fashion without information regarding the nature of the study. The EMGs were interpreted 3 times (discs A, B, C) 1 month apart. Clinical information was provided only with disc C. Intrarater reliability was calculated by comparing interpretations in discs A and B, interrater reliability by comparing interpretation between reviewers. Confirmation bias was estimated by the difference in correct interpretations when clinical information was provided. Results: Sensitivity was similar to previous reports (77%, confidence interval [CI] 63%–90%); specificity was 71%, CI 56%–85%. Intrarater reliability was good (κ 0.61, 95% CI 0.41–0.81); interrater reliability was lower (κ 0.53, CI 0.35–0.71). There was no substantial confirmation bias when clinical information was provided (absolute difference in correct responses 2.2%, CI −13.3% to 17.7%); the study lacked precision to exclude moderate confirmation bias. Conclusions: This study supports that (1) serial EMG studies should be performed by the same electromyographer since intrarater reliability is better than interrater reliability; (2) knowledge of clinical information does not bias EMG interpretation substantially; (3) EMG has moderate diagnostic accuracy for radiculopathy with modest specificity and electromyographers should exercise caution interpreting mild abnormalities. Classification of evidence: This study provides Class III evidence that EMG has moderate diagnostic accuracy and specificity for radiculopathy. PMID:26701380

Accuracy of a Portable Indirect Calorimeter for Measuring Resting Energy Expenditure in Individuals With Cancer.

PubMed

Purcell, Sarah A; Elliott, Sarah A; Ryan, Aoife M; Sawyer, Michael B; Prado, Carla M

2018-06-05

Determining optimal caloric intake for an individual with cancer is complicated by metabolic changes that occur, namely, alterations in resting energy expenditure (REE). There is currently no validated clinically available equation or tool to measure energy expenditure in these patients. Patients with newly diagnosed solid tumors underwent REE assessments using the FitMate GS portable indirect calorimeter and reference VMax metabolic cart; both used canopy hoods. REE was also estimated from the Harris-Benedict, Mifflin St. Jeor, and Henry equations for comparison. Data were analyzed using paired samples t-test and the Bland-Altman approach to assess group-level and individual-level agreement compared with the metabolic cart. A total 26 patients (19 males; body mass index: 27.8 ± 5.5 kg/m 2 ; age: 62 ± 10 years) participated in the study. Biases for the FitMate GS and both equations were low (ranging from -44 to -92 kcal or -2.3% to -5.1%), indicating good group-level accuracy. The FitMate GS had low bias, but the widest limits of agreement (-28.0% to 21.2%) compared with the 3 equations (Harris-Benedict: -15.8% to 11.2%; Mifflin St. Jeor: -17.1% to 6.9%; Henry: -15.4% to 11.5%). These differences were not due to volume of oxygen, BMI category, or sex. FitMate GS performed well on a group level, but its accuracy was poor on an individual level. Further research should develop better equations and validate tools to measure energy expenditure for accurate dietary recommendations for patients at nutrition risk. © 2018 American Society for Parenteral and Enteral Nutrition.

Validation of the Dutch version of the quick mild cognitive impairment screen (Qmci-D).

PubMed

Bunt, Steven; O'Caoimh, Rónán; Krijnen, Wim P; Molloy, D William; Goodijk, Geert Pieter; van der Schans, Cees P; Hobbelen, Hans J S M

2015-10-02

Differentiating mild cognitive impairment (MCI) from dementia is important, as treatment options differ. There are few short (<5 min) but accurate screening tools that discriminate between MCI, normal cognition (NC) and dementia, in the Dutch language. The Quick Mild Cognitive Impairment (Qmci) screen is sensitive and specific in differentiating MCI from NC and mild dementia. Given this, we adapted the Qmci for use in Dutch-language countries and validated the Dutch version, the Qmci-D, against the Dutch translation of the Standardised Mini-Mental State Examination (SMMSE-D). The Qmci was translated into Dutch with a combined qualitative and quantitative approach. In all, 90 participants were recruited from a hospital geriatric clinic (25 with dementia, 30 with MCI, 35 with NC). The Qmci-D and SMMSE-D were administered sequentially but randomly by the same trained rater, blind to the diagnosis. The Qmci-D was more sensitive than the SMMSE-D in discriminating MCI from dementia, with a significant difference in the area under the curve (AUC), 0.73 compared to 0.60 (p = 0.024), respectively, and in discriminating dementia from NC, with an AUC of 0.95 compared to 0.89 (p = 0.006). Both screening instruments discriminated MCI from NC with an AUC of 0.86 (Qmci-D) and 0.84 (SMMSE-D). The Qmci-D shows similar,(good) accuracy as the SMMSE-D in separating NC from MCI; greater,(albeit fair), accuracy differentiating MCI from dementia, and significantly greater accuracy in separating dementia from NC. Given its brevity and ease of administration, the Qmci-D seems a useful cognitive screen in a Dutch population. Further study with a suitably powered sample against more sensitive screens is now required.

Accuracy of pulse oximeter readings from probe placement on newborn wrist and ankle.

PubMed

Phattraprayoon, N; Sardesai, S; Durand, M; Ramanathan, R

2012-04-01

To compare the accuracy of pulse oximetry oxygen saturation (SpO(2)) measured on the wrist compared with the ipsilateral palm, and SpO(2) measured on the ankle compared with the ipsilateral sole. In this prospective observational study, neonates admitted to the neonatal intensive care unit were enrolled. We recorded SpO(2) (Masimo Radical-7 pulse oximeter) detected at the palm and ipsilateral wrist initially, then at 30 s, and at 1 min, and we repeated the same procedure over the sole and ipsilateral ankle. We recorded the time to obtain the SpO(2) readings from all these sites. Regression analysis was performed to determine the relationship between paired SpO(2) measurements. The mean difference (bias) and standard deviation of the paired SpO(2) differences (precision) were calculated (Bland-Altman plots). A total of 150 patients (birth weight 2381±1020 g, gestational age 34.3±4.3 weeks, median postnatal age 3.5 days (25th-75th percentile 1-16 days)) were enrolled. There was a good correlation between SpO(2) measured at the palm versus the wrist (r=0.95, P<0.001 (right); r=0.97, P< 0.001 (left)) and between SpO(2) measured at the sole versus the ankle (r=0.92, P<0.001 (right); r=0.91, P<0.001 (left)). There was also a good agreement between paired SpO(2) measurements from these sites. The bias and precision for SpO(2) at the right palm and right wrist was 0.08±0.94% and for the left palm and left wrist 0.22±0.87%. Similarly, the bias and precision for SpO(2) at the right sole and right ankle was -0.03±0.93% and for the left sole and left ankle was -0.01±0.93%. Our results show that the wrist and ankle can be used as alternative sites to measure SpO(2) in newborn infants in place of the routinely used palm or sole.

An ROC-type measure of diagnostic accuracy when the gold standard is continuous-scale.

PubMed

Obuchowski, Nancy A

2006-02-15

ROC curves and summary measures of accuracy derived from them, such as the area under the ROC curve, have become the standard for describing and comparing the accuracy of diagnostic tests. Methods for estimating ROC curves rely on the existence of a gold standard which dichotomizes patients into disease present or absent. There are, however, many examples of diagnostic tests whose gold standards are not binary-scale, but rather continuous-scale. Unnatural dichotomization of these gold standards leads to bias and inconsistency in estimates of diagnostic accuracy. In this paper, we propose a non-parametric estimator of diagnostic test accuracy which does not require dichotomization of the gold standard. This estimator has an interpretation analogous to the area under the ROC curve. We propose a confidence interval for test accuracy and a statistical test for comparing accuracies of tests from paired designs. We compare the performance (i.e. CI coverage, type I error rate, power) of the proposed methods with several alternatives. An example is presented where the accuracies of two quick blood tests for measuring serum iron concentrations are estimated and compared.