Accuracy Comparable (accuracy + comparable)

Distribution by Scientific Domains

Selected Abstracts

Quantitative trace element imaging using PIXE and the nuclear microprobe

C. G. Ryan
Abstract The X-ray spectra of pure elements, excited using MeV energy beam of protons from the nuclear microprobe, have known spectra signatures. This makes X-ray spectra for more complex mixtures amenable to decomposition into contributions from the component elements. By devising this procedure as a matrix operation that transforms directly from spectrum vector to elemental concentration vector, the decomposition can be performed very efficiently enabling the real-time projection of the component element signals. In the case of a raster-scanned beam, with data that contain position information for each X-ray event, this approach enables the real-time projection of component element spatial distribution images. This paper describes the matrix transform approach called dynamic analysis (DA), which enables on-line real-time imaging of major and trace elements using proton-induced X-ray emission (PIXE). The method also provides off-line iterative yield corrections to these images to compensate for changing sample composition across an image area. The resulting images are quantitative in two respects: (1) they resolve the pure element components and strongly reject interferences from other elements and (2) they can be directly interrogated for sample composition at each pixel, over areas, or along lines across the image area, with accuracy comparable to microanalytical point analysis methods. The paper describes the DA method, presents tests, and discusses its application to quantitative major and trace element imaging in geology. 2001 John Wiley & Sons, Inc. Int J Imaging Syst Technol 11, 219,230, 2000 [source]

Modeling of microwave devices with space mapping and radial basis functions

Slawomir Koziel
Abstract We review recent developments in space mapping techniques for modeling of microwave devices. We present a surrogate modeling methodology that utilizes space mapping combined with radial basis function interpolation. The method has advantages both over the standard space mapping modeling methodology and the recently published space mapping modeling with variable weight coefficients. In particular, it provides accuracy comparable or better than the latter method and computational efficiency as good as the standard space mapping modeling procedure. A comparison between the space mapping modeling methodologies as well as application examples of optimization and statistical analysis of microwave structures is presented. Copyright 2007 John Wiley & Sons, Ltd. [source]

Accuracy of brief and full forms of the child mania rating scale

David B. Henry
Abstract This study assesses the sensitivity of full and brief forms of a parent-rated mania scale to variations in diagnoses. Parents of a sample of 150 subjects either diagnosed with bipolar disorder (BD) or attention deficit hyperactivity disorder (ADHD), or healthy controls (HC), completed the full Child Mania Rating Scale and other measures. We used single-parameter item-response theory models to produce a brief parent mania rating scale from the full version. The 10-item, brief Child Mania Rating Scale,Parent (CMRS-P) version correlated .93 with 11 items from the full CMRS-P that were not used in constructing the brief version, and showed accuracy comparable to the full scale in differentiating BD from ADHD, and in discriminating among bipolar subtypes. 2008 Wiley Periodicals, Inc. J Clin Psychol 64:1,14, 2008. [source]

Correlation method for variance reduction of Monte Carlo integration in RS-HDMR

Genyuan Li
Abstract The High Dimensional Model Representation (HDMR) technique is a procedure for efficiently representing high-dimensional functions. A practical form of the technique, RS-HDMR, is based on randomly sampling the overall function and utilizing orthonormal polynomial expansions. The determination of expansion coefficients employs Monte Carlo integration, which controls the accuracy of RS-HDMR expansions. In this article, a correlation method is used to reduce the Monte Carlo integration error. The determination of the expansion coefficients becomes an iteration procedure, and the resultant RS-HDMR expansion has much better accuracy than that achieved by direct Monte Carlo integration. For an illustration in four dimensions a few hundred random samples are sufficient to construct an RS-HDMR expansion by the correlation method with an accuracy comparable to that obtained by direct Monte Carlo integration with thousands of samples. 2003 Wiley Periodicals, Inc. J Comput Chem 24: 277,283, 2003 [source]

Assessing the outdoor operating temperature of photovoltaic modules

David Faiman
Abstract By a careful study of data collected from seven varieties of photovoltaic (PV) module it is demonstrated that a simple modified form of the Hottel,Whillier,Bliss (HWB) equation, familiar from the analysis of flat-plate solar,thermal collectors, can be employed to predict module temperatures within an accuracy comparable to the cell-to-cell temperature differences typically encountered within a module. Furthermore, for modules within the range of construction parameters employed in this study, the actual values of the two modified HWB constants do not appear to depend upon module type. The implication of these results for the accuracy of outdoor module characterization is discussed. Copyright 2008 John Wiley & Sons, Ltd. [source]

Closely spaced external standard: a universal method of achieving 5 ppm mass accuracy over the entire MALDI plate in axial matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Eugene Moskovets
Close deposition of the sample and external standard was used in axial matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) to achieve mass accuracy equivalent to that obtained with an internal standard across the entire MALDI plate. In this work, the sample and external standard were deposited by continuous deposition in separate traces, each approximately 200,,m wide. The dependence of the mass accuracy on the distance between the sample and standard traces was determined across a MALDI target plate with dimensions of 57.5,mm,,57.0,mm by varying the gap between the traces from 100,,m to 4,mm. During acquisition, two adjacent traces were alternately irradiated with a 200-Hz laser, such that the peaks in the resulting mass spectra combined the sample and external standard. Ion suppression was not observed even when the peptide concentrations in the two traces differed by more than two orders of magnitude. The five peaks from the external standard trace were used in a four-term mass calibration of the masses of the sample trace. The average accuracy across the whole plate with this method was 5,ppm when peaks of the sample trace had signal-to-noise ratios of at least 30 and the gap between the traces was approximately 100,,m. This approach was applied to determining peptide masses of a reversed-phase liquid chromatographic (LC) separation of a tryptic digest of , -galactosidase deposited as a long serpentine trace across the MALDI plate, with accuracy comparable to that obtainable using internal calibration. In addition, the eluent from reversed-phase LC separation of a strong cation-exchange fraction containing tryptic peptides from a yeast lysate along with the closely placed external standard was deposited on the MALDI plate. The data obtained in the MS and MS/MS modes on a MALDI-TOF/TOF mass spectrometer were combined and used in database searching with MASCOT. Since the significant score is a function of mass accuracy in the MS mode, database searching with high mass accuracy reduced the number of false positives and also added peptides which otherwise would have been eliminated at lower mass accuracy (false negatives). Copyright 2003 John Wiley & Sons, Ltd. [source]

Detection of chromosomal aneusomy by fluorescence in situ hybridization for patients with nipple discharge

CANCER, Issue 3 2003
Daigo Yamamoto M.D.
Abstract BACKGROUND Breast carcinoma and precancer are believed to start in the lining of the milk duct or lobule. Ductography and fiberoptic ductoscopy (FDS) are used to identify abnormal intraductal lesions, although it is difficult to distinguish malignant from benign cases. Therefore, we studied the clinical usefulness of fluorescence in situ hybridization (FISH) analysis of a numerical aberration of chromosomes (aneusomy) using ductal lavage from patients with nipple discharge. METHODS We applied ductography and FDS to 90 women who had nipple discharge. Ductal lavages obtained from patients with positive ductography and/or FDS findings were subjected to cytology and FISH analysis using centromere probes for chromosomes 1, 11, and 17. Patients with samples that showed aneusomy in at least one of the three chromosomes were diagnosed as positive. RESULTS Histologic evaluation revealed 54 benign lesions and six malignancies. The sensitivity, specificity, and diagnostic accuracy were 33.3%, 88.9%, and 83.3%, respectively, for cytology and 100%, 100%, and 100%, respectively, for FISH. CONCLUSION The results demonstrated that FISH has a diagnostic accuracy comparable to cytology. This technique has 100% specificity is making a definitive diagnosis of malignancy in patients with indeterminate cytologic results, suggesting that FISH diagnosis can be a good adjunct to cytology. Cancer 2003;97:690,4. 2003 American Cancer Society. DOI 10.1002/cncr.11091 [source]