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1

Centroid finding method for position-sensitive detectors  

International Nuclear Information System (INIS)

A new centroid finding method for all detectors where the signal charge is collected or induced on strips of wires, or on subdivided resistive electrodes, is presented. The centroid of charge is determined by convolution of the sequentially switched outputs from these subdivisions or from the strips with a linear centroid finding filter. The position line width is inversely proportional to N/sup 3/2/, where N is the number of subdivisions

2

Modification of backgammon shape cathode and graded charge division readout method for a novel triple charge division centroid finding method  

International Nuclear Information System (INIS)

Triple Charge Division (TCD) centroid finding method that uses modified pattern of Backgammon Shape Cathode (MBSC) is introduced for medium range length position sensitive detectors with optimum numbers of cathode segments. MBSC pattern has three separated areas and uses saw tooth like insulator gaps for separating the areas. Side areas of the MBSC pattern are severed by a central common area. Size of the central area is twice of the size of both sides. Whereas central area is the widest area among three, both sides' areas have the main role in position sensing. With the same resolution and linearity, active region of original Backgammon pattern increases twice by using MBSC pattern, and with the same length, linearity of TCD centroid finding is much better than Backgammon charge division readout method. Linearity prediction of TCD centroid finding and experimental results conducted us to find an optimum truncation of the apices of MBCS pattern in the central area. The TCD centroid finding has an especial readout method since charges must be collected from two segments in both sides and from three segments in the central area of MBSC pattern. The so called Graded Charge Division (GCD) is the especial readout method for TCD. The GCD readout is a combination of the charge division readout and sequence grading of serial segments. Position sensing with TCD centroid finding and GCD readout were done by two sizes MBSC patterns (200mm and 80mm) and Spatial resolution about 1% of the detector length is achieved

3

High-position-resolution scintillation neutron-imaging detector by crossed-fiber readout with novel centroid-finding method  

CERN Document Server

Aiming at high-position-resolution and high-counting-rate neutron imaging, a novel centroid-finding method is proposed for a scintillation neutron-imaging detector with crossed-fiber readout. Crossed wavelength-shifting fibers are arranged on and under the scintillator. Luminescences generated in the scintillator are emitted and detected by a few fibers surrounding the incident point of a neutron. In the novel method, X and Y positions of the incident neutron are decided by coincidence of a central signal and neighboring signals, respectively. By fundamental experiments using a ZnS:Ag/ sup 6 LiF scintillator of 0.5-mm thickness and crossed wavelength-shifting fibers with a size of 0.5 x 0.5 mm sup 2 , it was confirmed that the position resolution is about 0.5 mm and the limitation of the neutron-counting rate is 320 kcps. (orig.)

Katagiri, M; Sakasai, K; Matsubayashi, M; Birumachi, A; Takahashi, H; Nakazawa, M

2002-01-01

4

Capacitive charge division in centroid finding cathode readouts in MWPCs  

International Nuclear Information System (INIS)

A technique is described in which the centroid of induced charge on cathode strips in a proportional chamber can be determined with reduced differential and integral nonlinearity, without increasing the number of readout channels. It is based on capacitive charge division from intermediate cathode strips to adjacent readout strips, and may be applied to a variety of position readout principles

5

A Method for Analog Implementation of Centroid Tracking Algorithm in a Video Signal  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The main goal of a video tracking algorithm is finding the location of a predefined target in successive video frames. Centroid pointing is one of the most efficient methods in the target tracking. This method can be simply implemented by a digital video processing system that includes a video memory and a powerful digital processor. Usually, the cost and the complexity of the digital video processor is high and in some applications, using analog video processor that includes only electronic ...

Payman Moallem; ?Aliakbar Shaemi?

2007-01-01

6

A Method for Analog Implementation of Centroid Tracking Algorithm in a Video Signal  

Directory of Open Access Journals (Sweden)

Full Text Available The main goal of a video tracking algorithm is finding the location of a predefined target in successive video frames. Centroid pointing is one of the most efficient methods in the target tracking. This method can be simply implemented by a digital video processing system that includes a video memory and a powerful digital processor. Usually, the cost and the complexity of the digital video processor is high and in some applications, using analog video processor that includes only electronic devices like OPAMP, diodes, transistors, resistors and capacitors has lower cost, more efficient and more reliable. Implementing of the centroid in an analog video processor is not as simple as digital one, therefore in this paper, we introduce a novel formulation of the centroid that can be implemented in an analog video processor. We simulate the proposed method by MatLab simulink and compare the results with the area-based tracking that is usually used in analog video processors. The simulation results show that the proposed method is more reliable and accurate.

Payman Moallem

2007-06-01

7

Alteração no método centroide de avaliação da adaptabilidade genotípica / Alteration of the centroid method to evaluate genotypic adaptability  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O objetivo deste trabalho foi alterar o método centroide de avaliação da adaptabilidade e estabilidade fenotípica de genótipos, para deixá-lo com maior sentido biológico e melhorar aspectos quantitativos e qualitativos de sua análise. A alteração se deu pela adição de mais três ideótipos, definidos [...] de acordo com valores médios dos genótipos nos ambientes. Foram utilizados dados provenientes de um experimento sobre produção de matéria seca de 92 genótipos de alfafa (Medicago sativa) realizado em blocos ao acaso, com duas repetições. Os genótipos foram submetidos a 20 cortes, no período de novembro de 2004 a junho de 2006. Cada corte foi considerado um ambiente. A inclusão dos ideótipos de maior sentido biológico (valores médios nos ambientes) resultou em uma dispersão gráfica em forma de uma seta voltada para a direita, na qual os genótipos mais produtivos ficaram próximos à ponta da seta. Com a alteração, apenas cinco genótipos foram classificados nas mesmas classes do método centroide original. A figura em forma de seta proporciona uma comparação direta dos genótipos, por meio da formação de um gradiente de produtividade. A alteração no método mantém a facilidade de interpretação dos resultados para a recomendação dos genótipos presente no método original e não permite duplicidade de interpretação dos resultados. Abstract in english ABSTRACT The objective of this work was to modify the centroid method of evaluation of phenotypic adaptability and the phenotype stability of genotypes in order for the method to make greater biological sense and improve its quantitative and qualitative performance. The method was modified by means [...] of the inclusion of three additional ideotypes defined in accordance with the genotypes' average yield in the environments tested. The alfalfa (Medicago sativa L.) forage yield of 92 genotypes was used. The trial had a randomized block design, with two replicates, and the data were used to test the method. The genotypes underwent 20 cuts, from November 2004 to June 2006. Each cut was considered an environment. The inclusion of ideotypes of greater biological average production in the environments produced an arrow-shaped graphical dispersion directed to the right in which the most productive genotypes were placed near the tip of the arrow. With the alteration only five genotypes were classified into the former classes of the original centroid method. The arrow-shaped figure allowed a direct comparison of genotypes throughout the productivity gradient. The alteration performed in the method preserved the easy interpretation of results for genotype recommendations of the original method, and does leaves no room for ambiguity in interpretation of the results.

Moysés, Nascimento; Cosme Damião, Cruz; Ana Carolina Mota, Campana; Rafael Simões, Tomaz; Caio Césio, Salgado; Reinaldo de Paula, Ferreira.

8

A further investigation of the centroid-to-centroid method for stereotactic lung radiotherapy: A phantom study  

Energy Technology Data Exchange (ETDEWEB)

Purpose: Our previous study [B. Lu et al., “A patient alignment solution for lung SBRT setups based on a deformable registration technique,” Med. Phys. 39(12), 7379–7389 (2012)] proposed a deformable-registration-based patient setup strategy called the centroid-to-centroid (CTC) method, which can perform an accurate alignment of internal-target-volume (ITV) centroids between averaged four-dimensional computed tomography and cone-beam computed tomography (CBCT) images. Scenarios with variations between CBCT and simulation CT caused by irregular breathing and/or tumor change were not specifically considered in the patient study [B. Lu et al., “A patient alignment solution for lung SBRT setups based on a deformable registration technique,” Med. Phys. 39(12), 7379–7389 (2012)] due to the lack of both a sufficiently large patient data sample and a method of tumor tracking. The aim of this study is to thoroughly investigate and compare the impacts of breathing pattern and tumor change on both the CTC and the translation-only (T-only) gray-value mode strategies by employing a four-dimensional (4D) lung phantom.Methods: A sophisticated anthropomorphic 4D phantom (CIRS Dynamic Thorax Phantom model 008) was employed to simulate all desired respiratory variations. The variation scenarios were classified into four groups: inspiration to expiration ratio (IE ratio) change, tumor trajectory change, tumor position change, tumor size change, and the combination of these changes. For each category the authors designed several scenarios to demonstrate the effects of different levels of breathing variation on both of the T-only and the CTC methods. Each scenario utilized 4DCT and CBCT scans. The ITV centroid alignment discrepancies for CTC and T-only were evaluated. The dose-volume-histograms (DVHs) of ITVs for two extreme cases were analyzed.Results: Except for some extreme cases in the combined group, the accuracy of the CTC registration was about 2 mm for all cases for both the single and the combined scenarios. The performance of the CTC method was insensitive to region-of-registration (ROR) size selections, as suggested by the comparable accuracy between 1 and 2 cm expansions of the ROR selections for the method. The T-only method was suitable for some single scenarios, such as trajectory variation, position variation, and size variation. However, for combined scenarios and/or a large variation in the IE ratio, the T-only method failed to produce reasonable registration results (within 3 mm). The discrepancy was close to, or even greater than, 1 cm. In addition, unlike the CTC method, the T-only method was sensitive to the ROR size selection. The DVH analysis suggested that a large ITV to PTV margin should be considered if a breathing pattern variation is observed.Conclusions: The phantom study demonstrated that the CTC method was reliable for scenarios in which breathing pattern variation was involved. The T-only gray value method worked for some scenarios, but not for scenarios that involved an IE ratio variation. For scenarios involving position variation, the T-only method worked only with a careful selection of the ROR, whereas the CTC method was independent of ROR size as long as the ITVs were included in the ROR. One indication of the dose consequence analysis was that a large ITV to PTV margin should be considered if a breathing pattern variation is observed.

Lu, Bo; Samant, Sanjiv; Mittauer, Kathryn; Lee, Soyoung; Huang, Yin; Li, Jonathan; Kahler, Darren; Liu, Chihray [Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, Florida 32610 (United States)

2013-10-15

9

A further investigation of the centroid-to-centroid method for stereotactic lung radiotherapy: A phantom study  

International Nuclear Information System (INIS)

Purpose: Our previous study [B. Lu et al., “A patient alignment solution for lung SBRT setups based on a deformable registration technique,” Med. Phys. 39(12), 7379–7389 (2012)] proposed a deformable-registration-based patient setup strategy called the centroid-to-centroid (CTC) method, which can perform an accurate alignment of internal-target-volume (ITV) centroids between averaged four-dimensional computed tomography and cone-beam computed tomography (CBCT) images. Scenarios with variations between CBCT and simulation CT caused by irregular breathing and/or tumor change were not specifically considered in the patient study [B. Lu et al., “A patient alignment solution for lung SBRT setups based on a deformable registration technique,” Med. Phys. 39(12), 7379–7389 (2012)] due to the lack of both a sufficiently large patient data sample and a method of tumor tracking. The aim of this study is to thoroughly investigate and compare the impacts of breathing pattern and tumor change on both the CTC and the translation-only (T-only) gray-value mode strategies by employing a four-dimensional (4D) lung phantom.Methods: A sophisticated anthropomorphic 4D phantom (CIRS Dynamic Thorax Phantom model 008) was employed to simulate all desired respiratory variations. The variation scenarios were classified into four groups: inspiration to expiration ratio (IE ratio) change, tumor trajectory change, tumor position change, tumor size change, and the combination of these changes. For each category the authors designed several scenarios to demonstrate the effects of different levels of breathing variation on both of the T-only and the CTC methods. Each scenario utilized 4DCT and CBCT scans. The ITV centroid alignment discrepancies for CTC and T-only were evaluated. The dose-volume-histograms (DVHs) of ITVs for two extreme cases were analyzed.Results: Except for some extreme cases in the combined group, the accuracy of the CTC registration was about 2 mm for all cases for both the single and the combined scenarios. The performance of the CTC method was insensitive to region-of-registration (ROR) size selections, as suggested by the comparable accuracy between 1 and 2 cm expansions of the ROR selections for the method. The T-only method was suitable for some single scenarios, such as trajectory variation, position variation, and size variation. However, for combined scenarios and/or a large variation in the IE ratio, the T-only method failed to produce reasonable registration results (within 3 mm). The discrepancy was close to, or even greater than, 1 cm. In addition, unlike the CTC method, the T-only method was sensitive to the ROR size selection. The DVH analysis suggested that a large ITV to PTV margin should be considered if a breathing pattern variation is observed.Conclusions: The phantom study demonstrated that the CTC method was reliable for scenarios in which breathing pattern variation was involved. The T-only gray value method worked for some scenarios, but not for scenarios that involved an IE ratio variation. For scenarios involving position variation, the T-only method worked only with a careful selection of the ROR, whereas the CTC method was independent of ROR size as long as the ITVs were included in the ROR. One indication of the dose consequence analysis was that a large ITV to PTV margin should be considered if a breathing pattern variation is observed

10

Star sub-pixel centroid calculation based on multi-step minimum energy difference method  

Science.gov (United States)

The star's centroid plays a vital role in celestial navigation, star images which be gotten during daytime, due to the strong sky background, have a low SNR, and the star objectives are nearly submerged in the background, takes a great trouble to the centroid localization. Traditional methods, such as a moment method, weighted centroid calculation method is simple but has a big error, especially in the condition of a low SNR. Gaussian method has a high positioning accuracy, but the computational complexity. Analysis of the energy distribution in star image, a location method for star target centroids based on multi-step minimum energy difference is proposed. This method uses the linear superposition to narrow the centroid area, in the certain narrow area uses a certain number of interpolation to pixels for the pixels' segmentation, and then using the symmetry of the stellar energy distribution, tentatively to get the centroid position: assume that the current pixel is the star centroid position, and then calculates and gets the difference of the sum of the energy which in the symmetric direction(in this paper we take the two directions of transverse and longitudinal) and the equal step length(which can be decided through different conditions, the paper takes 9 as the step length) of the current pixel, and obtain the centroid position in this direction when the minimum difference appears, and so do the other directions, then the validation comparison of simulated star images, and compare with several traditional methods, experiments shows that the positioning accuracy of the method up to 0.001 pixel, has good effect to calculate the centroid of low SNR conditions; at the same time, uses this method on a star map which got at the fixed observation site during daytime in near-infrared band, compare the results of the paper's method with the position messages which were known of the star, it shows that :the multi-step minimum energy difference method achieves a better effect.

Wang, Duo; Han, YanLi; Sun, Tengfei

2013-09-01

11

The efficiency of the centroid method compared to a simple average  

DEFF Research Database (Denmark)

Based on empirical data as well as a simulation study this paper gives recommendations with respect to situations wheere a simple avarage of the manifest indicators can be used as a close proxy for the centroid method and when it cannot.

Eskildsen, Jacob Kjær; Kristensen, Kai

12

Adaptive thresholding and dynamic windowing method for automatic centroid detection of digital Shack-Hartmann wavefront sensor  

International Nuclear Information System (INIS)

A Shack-Hartmann wavefront sensor (SWHS) splits the incident wavefront into many subsections and transfers the distorted wavefront detection into the centroid measurement. The accuracy of the centroid measurement determines the accuracy of the SWHS. Many methods have been presented to improve the accuracy of the wavefront centroid measurement. However, most of these methods are discussed from the point of view of optics, based on the assumption that the spot intensity of the SHWS has a Gaussian distribution, which is not applicable to the digital SHWS. In this paper, we present a centroid measurement algorithm based on the adaptive thresholding and dynamic windowing method by utilizing image processing techniques for practical application of the digital SHWS in surface profile measurement. The method can detect the centroid of each focal spot precisely and robustly by eliminating the influence of various noises, such as diffraction of the digital SHWS, unevenness and instability of the light source, as well as deviation between the centroid of the focal spot and the center of the detection area. The experimental results demonstrate that the algorithm has better precision, repeatability, and stability compared with other commonly used centroid methods, such as the statistical averaging, thresholding, and windowing algorithms.

13

A multi-resolution method for climate system modeling: application of Spherical Centroidal A multi-resolution method for climate system modeling: Application of Spherical Centroidal Voroni Tessellations  

Energy Technology Data Exchange (ETDEWEB)

During the next decade and beyond, climate system models will be challenged to resolve scales and processes that are far beyond their current scope. Each climate system component has its prototypical example of an unresolved process that may strongly influence the global climate system, ranging from eddy activity within ocean models, to ice streams within ice sheet models, to surface hydrological processes within land system models, to cloud processes within atmosphere models. These new demands will almost certainly result in the develop of multi-resolution schemes that are able, at least regional to faithfully simulate these fine-scale processes. Spherical Centroidal Voronoi Tessellations (SCVTs) offer one potential path toward the development of robust, multi-resolution climate system component models, SCVTs allow for the generation of high quality Voronoi diagrams and Delaunay triangulations through the use of an intuitive, user-defined density function, each of the examples provided, this method results in high-quality meshes where the quality measures are guaranteed to improve as the number of nodes is increased. Real-world examples are developed for the Greenland ice sheet and the North Atlantic ocean. Idealized examples are developed for ocean-ice shelf interaction and for regional atmospheric modeling. In addition to defining, developing and exhibiting SCVTs, we pair this mesh generation technique with a previously developed finite-volume method. Our numerical example is based on the nonlinear shallow-water equations spanning the entire surface of the sphere. This example is used to elucidate both the potential benefits of this multi-resolution method and the challenges ahead.

Ringler, Todd D [Los Alamos National Laboratory; Gunzburger, Max [FLORIDA STATE UNIV; Ju, Lili [UNIV OF SOUTH CAROLINA

2008-01-01

14

Comparison of pure and 'Latinized' centroidal Voronoi tessellation against various other statistical sampling methods  

International Nuclear Information System (INIS)

A recently developed centroidal Voronoi tessellation (CVT) sampling method is investigated here to assess its suitability for use in statistical sampling applications. CVT efficiently generates a highly uniform distribution of sample points over arbitrarily shaped M-dimensional parameter spaces. On several 2-D test problems CVT has recently been found to provide exceedingly effective and efficient point distributions for response surface generation. Additionally, for statistical function integration and estimation of response statistics associated with uniformly distributed random-variable inputs (uncorrelated), CVT has been found in initial investigations to provide superior points sets when compared against latin-hypercube and simple-random Monte Carlo methods and Halton and Hammersley quasi-random sequence methods. In this paper, the performance of all these sampling methods and a new variant ('Latinized' CVT) are further compared for non-uniform input distributions. Specifically, given uncorrelated normal inputs in a 2-D test problem, statistical sampling efficiencies are compared for resolving various statistics of response: mean, variance, and exceedence probabilities

15

Localization Methods of Weighted Centroid of dBZ on Weather-Radar Echo Maps in Vector Format  

Directory of Open Access Journals (Sweden)

Full Text Available Fast generation of weather-radar echo maps in vector format and accurate localization of weighted centroid of dBZ (dBZ stands for decibels of reflectivity of a radar signal reflected off a remote object are the basis of studying the characteristic tracking algorithms which are based on the vector echoes. The authors principally studied the approach to generating the vector echo map, and discussed the localization methods of weighted centroid of dBZ on vector echo maps. First, based on the traditional calculation method on raster echo data, some new localization methods of weighted centroid of dBZ on vector echo data were proposed by considering the weights of features’ area and distance from their location to radar center. Second, taking the base reflectivity products of CINRAD/SA weather radar in Meizhou city of China as data sources, they illustrated the storage structure of this type of echo data and studied the drawing mode of changing this type of data into vector format files under the polar coordinate system in detail. Third, using the same vector echo maps created by the above method, the weighted centroid of the same area was calculated by the above localization methods. In the end, Compared with the calculated value of the same area by traditional method which is based on raster echo maps, the three new calculated results and the sources of error were analyzed in detail and two conclusions were drawn: the echo’s precision in vector format is much higher than that in raster format and it is more accurate to take the features’ area and distance to radar center as weights during the calculation of weighted centroid of dBZ on echo maps in vector format.

Xue-tao Yu

2013-02-01

16

A multi-resolution method for climate system modeling: application of spherical centroidal Voronoi tessellations  

Energy Technology Data Exchange (ETDEWEB)

During the next decade and beyond, climate system models will be challenged to resolve scales and processes that are far beyond their current scope. Each climate system component has its prototypical example of an unresolved process that may strongly influence the global climate system, ranging from eddy activity within ocean models, to ice streams within ice sheet models, to surface hydrological processes within land system models, to cloud processes within atmosphere models. These new demands will almost certainly result in the develop of multiresolution schemes that are able, at least regionally, to faithfully simulate these fine-scale processes. Spherical centroidal Voronoi tessellations (SCVTs) offer one potential path toward the development of a robust, multiresolution climate system model components. SCVTs allow for the generation of high quality Voronoi diagrams and Delaunay triangulations through the use of an intuitive, user-defined density function. In each of the examples provided, this method results in high-quality meshes where the quality measures are guaranteed to improve as the number of nodes is increased. Real-world examples are developed for the Greenland ice sheet and the North Atlantic ocean. Idealized examples are developed for ocean–ice shelf interaction and for regional atmospheric modeling. In addition to defining, developing, and exhibiting SCVTs, we pair this mesh generation technique with a previously developed finite-volume method. Our numerical example is based on the nonlinear, shallow water equations spanning the entire surface of the sphere. This example is used to elucidate both the potential benefits of this multiresolution method and the challenges ahead.

Ringler, Todd [Los Alamos National Laboratory; Ju, Lili [University of South Carolina; Gunzburger, Max [Florida State University

2008-01-01

17

A novel, view-independent method for strain mapping in myocardial elastography: eliminating angle and centroid dependence  

International Nuclear Information System (INIS)

Robust indices of regional and global cardiac function are a key factor in detection and treatment of heart disease as well as understanding of the fundamental mechanisms of a healthy heart. Myocardial elastography provides a noninvasive method for imaging and measuring displacement and strain of the myocardium for the early detection of cardiovascular disease. However, two-dimensional in-plane axial and lateral strains measured depend on the sonographic view used. This becomes especially critical in a clinical setting and may induce large variations in the measured strains, potentially leading to false diagnoses. A novel method in myocardial elastography is proposed for eliminating this view dependence by deriving the polar, principal and classified principal strains. The performance of the proposed methodology is assessed by employing 3D finite-element left-ventricular models of a control and an ischemic canine heart. Although polar strains are angle-independent, they are sensitive to the selected reference coordinate system, which requires the definition of a centroid of the left ventricle (LV). In contrast, principal strains derived through eigenvalue decomposition exhibit the inherent characteristic of coordinate system independence, offering view (i.e., angle and centroid)-independent strain measurements. Classified principal strains are obtained by assigning the principal components in the physical ventricular coordinate system. An extensive strain analysis ille system. An extensive strain analysis illustrates the improvement in interpretation and visualization of the full-field myocardial deformation by using the classified principal strains, clearly depicting the ischemic and non-ischemic regions. Strain maps, independent of sonographic views and imaging planes, that can be used to accurately detect regional contractile dysfunction are demonstrated

18

Selection of Initial Centroids for k-Means Algorithm?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Clustering is one of the important data mining techniques. k-Means [1] is one of the mostimportant algorithm for Clustering. Traditional k-Means algorithm selects initial centroids randomly and ink-Means algorithm result of clustering highly depends on selection of initial centroids. k-Means algorithm issensitive to initial centroids so proper selection of initial centroids is necessary. This paper introduces anefficient method to start the k-Means with good initial centroids. Good initial ce...

Baswade, Anand M.; Nalwade?, Prakash S.

2013-01-01

19

Geogebra: Calculation of Centroid  

Directory of Open Access Journals (Sweden)

Full Text Available Our paper is result of the research done in a special direction for solving problems of physics by using GeoGebra programme: calculation of centroid. Lots of simulations of physical phenomena from the class of Mechanics can be performed and computational problems can be solved with GeoGebra. GeoGebra offers many commands and one of them is the command “centroid” to calculate the coordinates of the centroid of a polygon but, we have created a new tool to calculate the coordinates of the centroid of a plane region bounded by curves. Our work is part of the passionate work of many GeoGebra users which will result with a very rich fund of GeoGebra virtual tools, examples and experiences that will be worldwidely available for many teachers and practioners.

Qamil Kllogjeri

2012-09-01

20

Centroid Based Text Clustering  

Directory of Open Access Journals (Sweden)

Full Text Available Web mining is a burgeoning new field that attempts to glean meaningful information from natural language text. Web mining refers generally to the process of extracting interesting information and knowledge from unstructured text. Text clustering is one of the important Web mining functionalities. Text clustering is the task in which texts are classified into groups of similar objects based on their contents. Current research in the area of Web mining is tacklesproblems of text data representation, classification, clustering, information extraction or the search for and modeling of hidden patterns. In this paper we propose for mining large document collections it is necessary to pre-process the web documents and store the information in a data structure, which is more appropriate for further processing than a plain web file. In this paper we developed a php-mySql based utility to convert unstructured web documents into structured tabular representation by preprocessing, indexing .We apply centroid based web clustering method on preprocessed data. We apply three methods for clustering. Finally we proposed a method that can increase accuracy based on clustering ofdocuments.

Priti Maheshwari

2010-09-01

 
 
 
 
21

Selection of Initial Centroids for k-Means Algorithm?  

Directory of Open Access Journals (Sweden)

Full Text Available Clustering is one of the important data mining techniques. k-Means [1] is one of the mostimportant algorithm for Clustering. Traditional k-Means algorithm selects initial centroids randomly and ink-Means algorithm result of clustering highly depends on selection of initial centroids. k-Means algorithm issensitive to initial centroids so proper selection of initial centroids is necessary. This paper introduces anefficient method to start the k-Means with good initial centroids. Good initial centroids are useful for betterclustering.

Anand M. Baswade

2013-07-01

22

Application example: Preliminary Results of ISOLA use to find moment tensor solutions and centroid depth applied to aftershocks of Mw=8.8 February 27 2010, Maule Earthquake  

Science.gov (United States)

We selected seven aftershocks from Maule earthquake between 33.5°S to 35°S from May to September to find single source inversion. The data were provided by XY Chile Ramp Experiment* which was deployed after great Maule earthquake. Waveform data are from 13 broad band stations chosen from the 58 broad band stations deployed by IRIS-PASCAL from April to September 2010. Stations are placed above the normal subduction section south of ~33.5°S. Events were located with an iterative software called Hypocenter using one dimensional local model, obtained above for the forearc region between 33°S to 35°S. We used ISOLA which is a fortran code with a Matlab interface to obtain moment tensors solutions, optimum position and time of the subevents. Values depth obtained by a grid search of centroid position show range values which are compatibles with the interplate seismogenic zone. Double-Couple focal mechanism solutions (Figure 1) show 4 thrust events which can be associated with that zone. However, only one of them has strike, dip and rake of 358°, 27° and 101 respectively, appropriate to be expected for interplate seismogenic zone. On the other hand, the other 3 events show strike and normal double-couple focal mechanism solutions (Figure 1). This last topic makes association to those events to the contact of the Nazca and South American plate difficult. Nevertheless, in a first stage, their depths may allow possibility of an origin there. * The facilities of the IRIS Data Management System, and specifically the IRIS Data Management Center, were used for access to waveform, metadata or products required in this study. The IRIS DMS is funded through the National Science Foundation and specifically the GEO Directorate through the Instrumentation and Facilities Program of the National Science Foundation under Cooperative Agreement EAR-0552316. Some activities of are supported by the National Science Foundation EarthScope Program under Cooperative Agreement EAR-0733069. Figure 1. Doble-Couple focal mechanisms solutions from Moment Tensor Inversion using ISOLA. Triangles show broad band stations used in this work from IRIS-PASSCAL.

Nacif, S. V.; Sanchez, M. A.

2013-05-01

23

A Robust Front-End Processor combining Mel Frequency Cepstral Coefficient and Sub-band Spectral Centroid Histogram methods for Automatic Speech Recognition  

Directory of Open Access Journals (Sweden)

Full Text Available Environmental robustness is an important area of research in speech recognition. Mismatch between trained speech models and actual speech to be recognized is due to factors like background noise. It can cause severe degradation in the accuracy of recognizers whichare based on commonly used features like mel-frequency cepstral co-efficient (MFCC and linear predictive coding (LPC. It is well understood that all previous auditory based feature extraction methods perform extremely well in terms of robustness due to the dominantfrequency information present in them. But these methods suffer from high computational cost. Another method called sub-band spectral centroid histograms (SSCH integrates dominant-frequency information with sub-band power information. This method is based onsub-band spectral centroids (SSC which are closely related to spectral peaks for both clean and noisy speech. Since SSC can be computed efficiently from short-term speech power spectrum estimate, SSCH method is quite robust to background additive noise at a lowercomputational cost. It has been noted that MFCC method outperforms SSCH method in the case of clean speech. However in the case of speech with additive noise, MFCC method degrades substantially. In this paper, both MFCC and SSCH feature extraction have beenimplemented in Carnegie Melon University (CMU Sphinx 4.0 and trained and tested on AN4 database for clean and noisy speech. Finally, a robust speech recognizer which automatically employs either MFCC or SSCH feature extraction methods based on the variance of shortterm power of the input utterance is suggested.

R. Thangarajan

2009-06-01

24

Multiple Centroid Methodology to analyze genotype adaptability  

Directory of Open Access Journals (Sweden)

Full Text Available This study was carried out to propose a modification of the centroid method. The method is modified in thechoice of the ideotype, to be defined according to the researcher's interest, using the bi-segmented regression model, ratherthan based on experimental data, which limit the comparison of genotypes. To illustrate the method, one trait was simulatedin 25 genotypes in 8 environments. For the simulations and statistical analyses the software package GENES was used. Themultiple centroid is more flexible than the original centroid method, since it can be used according to the researcher's objectiveand the desired recommendation strategy. It is also readily interpretable for recommendation and unambiguous. Besides, thenumber of genotypes of interest can be compared, making a detailed study possible, by separating the genotypes intorecommendation classes.

Moysés Nascimento

2009-01-01

25

Combined use of the centroid and matched filtering spectral magnetic methods in determining thermomagnetic characteristics of the crust in the structural provinces of Central Brazil  

Science.gov (United States)

Spectral analysis of data acquired in twelve different aeromagnetic surveys of central Brazil has led to new insights in the magnetic characteristics of the lithosphere in the structural provinces of Tocantins and São Francisco. Since centroid-based spectral magnetic methods do not model the spectrum explicitly, they are used for the first time in conjunction with the matched filtering spectral modeling method to verify that appropriate slope segments are fit when determining source depths. The Tocantins province is characterized by subdued variations in the thickness of magnetized layers, most of which may be associated with structural discontinuities and subcrustal intrusions. In contrast, variations in thickness of magnetized crustal layers are more prevalent in the São Francisco province. The depths to the bottom of magnetized crust in the Tocantins province are, in general, less than 30-35 km, whereas they reach depths greater than 40 km in the São Francisco province. In parts of São Francisco craton, the depths to the bottom of magnetized crust are greater than the crustal thickness determined from seismic refraction and receiver function studies. However, these are indistinguishable in terms of resolution of the two methods. Analysis of heat flow data and results of thermal modeling indicate depths of Curie isotherms consistent with estimates from spectral analysis of aeromagnetic data. Hence the possibility that the uppermost part of mantle under the São Francisco craton may be ferromagnetic cannot be dismissed.

Guimarães, S. N. P.; Ravat, D.; Hamza, V. M.

2014-06-01

26

Evidence for subduction beneath Gibraltar Arc and Andean regions from k-means earthquake centroids  

Science.gov (United States)

k-Means algorithms are widely used for determining clusters in broad types of datasets. Since zones of high seismic activity as plate boundary present diffuse seismicity patterns, the use of k-algorithm is a way to classify earthquakes in terms of centroids. Mapping centroids improves seismic visibility for further tectonic interpretation. We used selected datasets of earthquakes and determined the number of clusters or values of k by introducing the silhouette index method to check the validity of cluster numbers. By introducing magnitude size in the vectorial attributes, k-means algorithm provides a map of centroids that represents the location of high seismic energy, which is useful in seismic risk assessment. By including the depth of seismic events as the main attribute, we obtained spatiotemporal variations of centroids, which improve the image resolution of seismicity at depth to find out the underlying dynamic process. This has been achieved in subduction zone of Chile where the presence of slab is reflected by centroid distribution. The method is particularly relevant to complex seismic zones where controversial geodynamic models are reported such as the Gibraltar Arc. Resulting model supports W-oriented subduction underlying many parts of the Gibraltar zone.

Ramdani, Faiçal; Kettani, Omar; Tadili, Benaissa

2014-09-01

27

Comparação dos métodos de determinação da estabilidade oxidativa de biodiesel B100, em mistura com antioxidantes sintéticos: aplicação do delineamento simplex-centroide com variável de processo Comparison of methods for determination of oxidative stability of B100 biodiesel mixed with synthetic antioxidants: application of simplex-centroid design with process variable  

Directory of Open Access Journals (Sweden)

Full Text Available The Rancimat and accelerated stove tests were used to determine the oxidative stability of B100 biodiesel mixed with synthetic antioxidants. The predictive equations, with process variable, were obtained by applying a simplex-centroid design. Regardless of the antioxidant used, all assays carried out with the accelerated stove test presented storage time longer than 177.88 d, the greatest value obtained by applying the Rancimat test. The t test, applied to the parameters containing the process variable, showed a statistically significant difference (at the level of 5% between the methods used.

João Rafael de Moraes Cini

2013-01-01

28

CCD centroiding analysis for Nano-JASMINE observation data  

Science.gov (United States)

Nano-JASMINE is a very small satellite mission for global space astrometry with milli-arcsecond accuracy, which will be launched in 2011. In this mission, centroids of stars in CCD image frames are estimated with sub-pixel accuracy. In order to realize such a high precision centroiding an algorithm utilizing a least square method is employed. One of the advantages is that centroids can be calculated without explicit assumption of the point spread functions of stars. CCD centroiding experiment has been performed to investigate whether this data analysis is available, and centroids of artificial star images on a CCD are determined with a precision of less than 0.001 pixel. This result indicates parallaxes of stars within 300 pc from Sun can be observed in Nano-JASMINE.

Niwa, Yoshito; Yano, Taihei; Araki, Hiroshi; Gouda, Naoteru; Kobayashi, Yukiyasu; Yamada, Yoshiyuki; Tazawa, Seiichi; Hanada, Hideo

2010-07-01

29

Shack-Hartmann centroid detection using the spiral phase transform.  

Science.gov (United States)

We present a Shack-Hartmann (SH) centroid detection algorithm capable to measure in presence of strong noise, background illumination and spot modulating signals, which are typical limiting factors of traditional centroid detection algorithms. The proposed method is based on performing a normalization of the SH pattern using the spiral phase transform method and Fourier filtering. The spot centroids are then obtained using global thresholding and weighted average methods. We have tested the algorithm with simulations and experimental data obtaining satisfactory results. A complete MATLAB package that can reproduce all the results can be downloaded from [http://goo.gl/o2JhD]. PMID:23089793

Vargas, J; Restrepo, R; Estrada, J C; Sorzano, C O S; Du, Yong-Zhao; Carazo, J M

2012-10-20

30

Analysis of the positon resolution in centroid measurements in MWPC  

International Nuclear Information System (INIS)

Resolution limits in avalanche localization along the anode wires of an MWPC with cathodes connected by resistors and equally spaced amplifiers, are evaluated. A simple weighted-centroid method and a highly linear method based on a linear centroid finding filter, are considered. The contributions to the variance of the estimator of the avalanche position, due to the series noise of the amplifiers and to the thermal noise of the resistive line are separately calculated and compared. A comparison is made with the resolution of the MWPC with isolated cathodes. The calculations are performed with a distributed model of the diffusive line formed by the cathodes and the resistors. A comparison is also made with the results obtained with a simple lumped model of the diffusive line. A number of graphs useful in determining the best parameters of a MWPC, with a specified position and time resolution, are given. It has been found that, for short resolution times, an MWPC with cathodes connected by resitors presents better resolution (lower variance of the estimator of the avalanche position) than an MWPC with isolated cathodes. Conversely, for long resolution times, the variance of the estimator of the avalanche position is lower in an MWPC with isolated cathodes. (orig.)

31

STATISTICS OF CENTROIDS OF VELOCITY  

Directory of Open Access Journals (Sweden)

Full Text Available We review the use of velocity centroids statistics to recover information of interstellar turbulence from observations. Velocity centroids have been used for a long time now to retrieve information about the scaling properties of the turbulent velocity field in the interstellar medium. We show that, while they are useful to study subsonic turbulence, they do not trace the statistics of velocity in supersonic turbulence, because they are highly influenced by fluctuations of density. We show also that for sub-Alfvénic turbulence (both supersonic and subsonic two-point statistics (e.g. correlation functions or power-spectra are anisotropic. This anisotropy can be used to determine the direction of the mean magnetic field projected in the plane of the sky.

A. Esquivel

2009-01-01

32

Comparison of Blaugrund and Monte Carlo centroid-shift calculations  

International Nuclear Information System (INIS)

A comparison of Blaugrund and Monte Carlo centroid-shift calculations is presented. We find that the two methods of calculation agree to within 15% if the lifetime is greater than several times the flight time between collisions. The differences are systematic and hence predictable. These discrepancies depend only weakly on the reduced energy parameter epsilon and are a function of the mass ratio only when the projectile-target mass ratio is close to unity. Furthermore, the discrepancies between these methods of calculation only show a weak dependence on the choice of atomic interaction potential. On the other hand, for lifetimes that are shorter than a few times the flight time between collisions, the situation is more complex. (orig.)

33

CCD centroiding experiment for JASMINE and ILOM  

Science.gov (United States)

JASMINE and ILOM are space missions which are in progress at the National Astronomical Observatory of Japan. These two projects need a common astrometric technique to obtain precise positions of star images on solid state detectors to accomplish the objectives. We have carried out measurements of centroid of artificial star images on a CCD to investigate the accuracy of the positions of the stars, using an algorithm for estimating them from photon weighted means of the stars. We find that the accuracy of the star positions reaches 1/300 pixel for one measurement. We also measure positions of stars, using an algorithm for correcting the distorted optical image. Finally, we find that the accuracy of the measurement for the positions of the stars from the strongly distorted image is under 1/150 pixel for one measurement.

Yano, Taihei; Araki, Hiroshi; Gouda, Naoteru; Kobayashi, Yukiyasu; Tsujimoto, Takuji; Nakajima, Tadashi; Kawano, Nobuyuki; Tazawa, Seiichi; Yamada, Yoshiyuki; Hanada, Hideo; Asari, Kazuyoshi; Tsuruta, Seiitsu

2006-06-01

34

The Differential Form Method for Finding Symmetries  

Directory of Open Access Journals (Sweden)

Full Text Available This article reviews the use of differential forms and Lie derivatives to find symmetries of differential equations, as originally presented in Harrison and Estabrook, J. Math. Phys., 12 (1971, 653. An outline of the method is given, followed by examples and references to recent papers using the method.

B. Kent Harrison

2005-08-01

35

Content Based Image Retrieval by using Multi Layer Centroid Contour Distance  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper we present a new approach to measuring similarity between two shape of object. In conventional method, centroid contour distance (CCD is formed by measuring distance between centroid (center and boundary of object, but this method cannot capture if an object have multiple boundary in the same angle. We develop a novel approach feature shape by measuring distance between centroid (center and boundary of object that can capture multiple boundaries in the same angle or multi-layer centroid contour distance (MLCCD. The experiment result on simulation dataset and plankton dataset show that the proposed method (MLCCD better than the conventional method (CCD.

Kohei Arai

2013-03-01

36

Quantum spatial superresolution by optical centroid measurements  

CERN Document Server

Quantum lithography (QL) has been suggested as a means of achieving enhanced spatial resolution for optical imaging, but its realization has been held back by the low multi-photon detection rates of recording materials. Recently, an optical centroid measurement (OCM) procedure was proposed as a way to obtain spatial resolution enhancement identical to that of QL but with higher detection efficiency (M. Tsang, Phys. Rev. Lett. 102, 253601, 2009). Here we describe a variation of the OCM method with still higher detection efficiency based on the use of photon-number-resolving detection. We also report laboratory results for two-photon interference. We compare these results with those of the standard QL method based on multi-photon detection and show that the new method leads to superresolution but with higher detection efficiency.

Shin, Heedeuk; Chang, Hye Jeong; Boyd, Robert W

2011-01-01

37

Point estimation of root finding methods  

CERN Document Server

This book sets out to state computationally verifiable initial conditions for predicting the immediate appearance of the guaranteed and fast convergence of iterative root finding methods. Attention is paid to iterative methods for simultaneous determination of polynomial zeros in the spirit of Smale's point estimation theory, introduced in 1986. Some basic concepts and Smale's theory for Newton's method, together with its modifications and higher-order methods, are presented in the first two chapters. The remaining chapters contain the recent author's results on initial conditions guaranteing convergence of a wide class of iterative methods for solving algebraic equations. These conditions are of practical interest since they depend only on available data, the information of a function whose zeros are sought and initial approximations. The convergence approach presented can be applied in designing a package for the simultaneous approximation of polynomial zeros.

2008-01-01

38

Finding protein sites using machine learning methods  

Directory of Open Access Journals (Sweden)

Full Text Available The increasing amount of protein three-dimensional (3D structures determined by x-ray and NMR technologies as well as structures predicted by computational methods results in the need for automated methods to provide inital annotations. We have developed a new method for recognizing sites in three-dimensional protein structures. Our method is based on a previosly reported algorithm for creating descriptions of protein microenviroments using physical and chemical properties at multiple levels of detail. The recognition method takes three inputs: 1. A set of control nonsites that share some structural or functional role. 2. A set of control nonsites that lack this role. 3. A single query site. A support vector machine classifier is built using feature vectors where each component represents a property in a given volume. Validation against an independent test set shows that this recognition approach has high sensitivity and specificity. We also describe the results of scanning four calcium binding proteins (with the calcium removed using a three dimensional grid of probe points at 1.25 angstrom spacing. The system finds the sites in the proteins giving points at or near the blinding sites. Our results show that property based descriptions along with support vector machines can be used for recognizing protein sites in unannotated structures.

Jaime Leonardo Bobadilla Molina

2010-04-01

39

Maser Source Finding Methods in HOPS  

CERN Document Server

The {\\bf H}$_2${\\bf O} Southern Galactic {\\bf P}lane {\\bf S}urvey (HOPS) has observed 100 square degrees of the Galactic plane, using the Mopra radio telescope to search for emission from multiple spectral lines in the 12\\,mm band (19.5\\,--\\,27.5\\,GHz). Perhaps the most important of these spectral lines is the 22.2\\,GHz water maser transition. We describe the methods used to identify water maser candidates and subsequent confirmation of the sources. Our methods involve a simple determination of likely candidates by searching peak emission maps, utilising the intrinsic nature of water maser emission - spatially unresolved and spectrally narrow-lined. We estimate completeness limits and compare our method with results from the {\\sc Duchamp} source finder. We find that the two methods perform similarly. We conclude that the similarity in performance is due to the intrinsic limitation of the noise characteristics of the data. The advantages of our method are that it is slightly more efficient in eliminating spuri...

Walsh, Andrew J; Longmore, Steven; Jordan, Christopher H; Lowe, Vicki

2011-01-01

40

Particle identification by modified Bragg-curve centroid detection  

International Nuclear Information System (INIS)

A new article identification method based on the measurement of Bragg-curve centroids using a gas-filled ionization chamber has been improved for detection of low-energy particles around 1 MeV per nucleon by introducing a nonuniform distribution of resistance on the anode electrode. Almost the same quality of Z-resolutions as in the conventional ?E-E method could be obtained up to Z=19. (orig.)

 
 
 
 
41

The Burbea-Rao and Bhattacharyya centroids  

CERN Document Server

We study the centroid with respect to the class of information-theoretic distortion measures called Burbea-Rao divergences. Burbea-Rao divergences generalize the Jensen-Shannon divergence by measuring the non-negative Jensen difference induced by a strictly convex and differentiable function expressing a measure of entropy. We first show that a symmetrization of Bregman divergences called Jensen-Bregman distances yields a natural definition of Burbea-Rao divergences. We then define skew Burbea-Rao divergences, and prove that skew Burbea-Rao divergences amount to compute Bregman divergences in asymptotical cases. We prove that Burbea-Rao centroids are always unique, and we design a generic iterative algorithm for efficiently estimating those centroids with guaranteed convergence. In statistics, the Bhattacharyya distance is widely used to measure the degree of overlap of probability distributions. This distance notion is all the more useful as it provides both upper and lower bounds on Bayes misclassification ...

Nielsen, Frank

2010-01-01

42

Evaluation of centroiding algorithm error for Nano-JASMINE  

Science.gov (United States)

The Nano-JASMINE mission has been designed to perform absolute astrometric measurements with unprecedented accuracy; the end-of-mission parallax standard error is required to be of the order of 3 milli arc seconds for stars brighter than 7.5 mag in the zw-band(0.6?m-1.0?m) .These requirements set a stringent constraint on the accuracy of the estimation of the location of the stellar image on the CCD for each observation. However each stellar images have individual shape depend on the spectral energy distribution of the star, the CCD properties, and the optics and its associated wave front errors. So it is necessity that the centroiding algorithm performs a high accuracy in any observables. Referring to the study of Gaia, we use LSF fitting method for centroiding algorithm, and investigate systematic error of the algorithm for Nano-JASMINE. Furthermore, we found to improve the algorithm by restricting sample LSF when we use a Principle Component Analysis. We show that centroiding algorithm error decrease after adapted the method.

Hara, Takuji; Gouda, Naoteru; Yano, Taihei; Yamada, Yoshiyuki

2014-08-01

43

Foot Bone in Vivo: Its Center of Mass and Centroid of Shape  

CERN Document Server

This paper studies foot bone geometrical shape and its mass distribution and establishes an assessment method of bone strength. Using spiral CT scanning, with an accuracy of sub-millimeter, we analyze the data of 384 pieces of foot bones in vivo and investigate the relationship between the bone's external shape and internal structure. This analysis is explored on the bases of the bone's center of mass and its centroid of shape. We observe the phenomenon of superposition of center of mass and centroid of shape fairly precisely, indicating a possible appearance of biomechanical organism. We investigate two aspects of the geometrical shape, (i) distance between compact bone's centroid of shape and that of the bone and (ii) the mean radius of the same density bone issue relative to the bone's centroid of shape. These quantities are used to interpret the influence of different physical exercises imposed on bone strength, thereby contributing to an alternate assessment technique to bone strength.

Fan, Yifang; Fan, Yubo; Lin, Zhiyu; Lv, Changsheng

2010-01-01

44

Global Optimization of Centroidal Voronoi Tessellation with Monte Carlo Approach.  

Science.gov (United States)

Centroidal Voronoi tessellation (CVT) is a widely used geometric structure in applications including mesh generation, vector quantization and image processing. Global optimization of the CVT function is important in these applications. With numerical evidences, we show that the CVT function is highly non-convex and has many local minima and therefore the global optimization of the CVT function is nontrivial. We apply the method of {\\em Monte Carlo with minimization} (MCM) to optimizing the CVT function globally and demonstrate its efficacy in producing much improved results compared with two other global optimization methods. PMID:22291151

Lu, Lin; Sun, Feng; Pan, Hao; Wang, Wenping

2012-01-26

45

Radiographic measures of thoracic kyphosis in osteoporosis: Cobb and vertebral centroid angles  

International Nuclear Information System (INIS)

Several measures can quantify thoracic kyphosis from radiographs, yet their suitability for people with osteoporosis remains uncertain. The aim of this study was to examine the validity and reliability of the vertebral centroid and Cobb angles in people with osteoporosis. Lateral radiographs of the thoracic spine were captured in 31 elderly women with osteoporosis. Thoracic kyphosis was measured globally (T1-T12) and regionally (T4-T9) using Cobb and vertebral centroid angles. Multisegmental curvature was also measured by fitting polynomial functions to the thoracic curvature profile. Canonical and Pearson correlations were used to examine correspondence; agreement between measures was examined with linear regression. Moderate to high intra- and inter-rater reliability was achieved (SEM = 0.9-4.0 ). Concurrent validity of the simple measures was established against multisegmental curvature (r = 0.88-0.98). Strong association was observed between the Cobb and centroid angles globally (r = 0.84) and regionally (r 0.83). Correspondence between measures was moderate for the Cobb method (r 0.72), yet stronger for the centroid method (r = 0.80). The Cobb angle was 20% greater for regional measures due to the influence of endplate tilt. Regional Cobb and centroid angles are valid and reliable measures of thoracic kyphosis in people with osteoporosis. However, the Cobb angle is biased by endplate tilt, suggesting that the centroid angle is more appropriate for this populationle is more appropriate for this population. (orig.)

46

Radiographic measures of thoracic kyphosis in osteoporosis: Cobb and vertebral centroid angles  

Energy Technology Data Exchange (ETDEWEB)

Several measures can quantify thoracic kyphosis from radiographs, yet their suitability for people with osteoporosis remains uncertain. The aim of this study was to examine the validity and reliability of the vertebral centroid and Cobb angles in people with osteoporosis. Lateral radiographs of the thoracic spine were captured in 31 elderly women with osteoporosis. Thoracic kyphosis was measured globally (T1-T12) and regionally (T4-T9) using Cobb and vertebral centroid angles. Multisegmental curvature was also measured by fitting polynomial functions to the thoracic curvature profile. Canonical and Pearson correlations were used to examine correspondence; agreement between measures was examined with linear regression. Moderate to high intra- and inter-rater reliability was achieved (SEM = 0.9-4.0 ). Concurrent validity of the simple measures was established against multisegmental curvature (r = 0.88-0.98). Strong association was observed between the Cobb and centroid angles globally (r = 0.84) and regionally (r = 0.83). Correspondence between measures was moderate for the Cobb method (r = 0.72), yet stronger for the centroid method (r = 0.80). The Cobb angle was 20% greater for regional measures due to the influence of endplate tilt. Regional Cobb and centroid angles are valid and reliable measures of thoracic kyphosis in people with osteoporosis. However, the Cobb angle is biased by endplate tilt, suggesting that the centroid angle is more appropriate for this population. (orig.)

Briggs, A.M.; Greig, A.M. [University of Melbourne, Centre for Health, Exercise and Sports Medicine, School of Physiotherapy, Victoria (Australia); University of Melbourne, Department of Medicine, Royal Melbourne Hospital, Victoria (Australia); Wrigley, T.V.; Tully, E.A.; Adams, P.E.; Bennell, K.L. [University of Melbourne, Centre for Health, Exercise and Sports Medicine, School of Physiotherapy, Victoria (Australia)

2007-08-15

47

GPU-assisted computation of centroidal Voronoi tessellation.  

Science.gov (United States)

Centroidal Voronoi tessellations (CVT) are widely used in computational science and engineering. The most commonly used method is Lloyd's method, and recently the L-BFGS method is shown to be faster than Lloyd's method for computing the CVT. However, these methods run on the CPU and are still too slow for many practical applications. We present techniques to implement these methods on the GPU for computing the CVT on 2D planes and on surfaces, and demonstrate significant speedup of these GPU-based methods over their CPU counterparts. For CVT computation on a surface, we use a geometry image stored in the GPU to represent the surface for computing the Voronoi diagram on it. In our implementation a new technique is proposed for parallel regional reduction on the GPU for evaluating integrals over Voronoi cells. PMID:21233516

Rong, Guodong; Liu, Yang; Wang, Wenping; Yin, Xiaotian; Gu, Xianfeng David; Guo, Xiaohu

2011-03-01

48

JASMINE project Instrument design and centroiding experiment  

Science.gov (United States)

JASMINE will study the fundamental structure and evolution of the Milky Way Galaxy. To accomplish these objectives, JASMINE will measure trigonometric parallaxes, positions and proper motions of about 10 million stars with a precision of 10 ?arcsec at z = 14 mag. In this paper the instrument design (optics, detectors, etc.) of JASMINE is presented. We also show a CCD centroiding experiment for estimating positions of star images. The experimental result shows that the accuracy of estimated distances has a variance of less than 0.01 pixel.

Yano, Taihei; Gouda, Naoteru; Kobayashi, Yukiyasu; Yamada, Yoshiyuki

49

Centroid Velocity Statistics of Molecular Clouds  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We compute structure functions and Fourier spectra of 2D centroid velocity (CV) maps in order to study the gas dynamics of typical molecular clouds (MCs) in numerical simulations. We account for a simplified treatment of time-dependent chemistry and the non-isothermal nature of the gas and use a 3D radiative transfer tool to model the CO line emission in a post-processing step. We perform simulations using three different initial mean number densities of n_0 = 30, 100 and 30...

Bertram, Erik; Konstandin, Lukas; Shetty, Rahul; Glover, Simon C. O.; Klessen, Ralf S.

2014-01-01

50

Centroid moment tensor catalogue for Indonesia  

Science.gov (United States)

We developed a centroid moment tensor (CMT) catalogue of earthquakes in and around Indonesia (InaCMT) using data from the nationwide broadband seismograph network in Indonesia. We obtained CMT solutions for about 500 earthquakes that occurred in and around Indonesia between 2006 and 2009. The moment magnitudes ranged from 4.5 to 8.3. We examined the accuracy of the CMT solutions of the InaCMT catalogue by comparing them with those obtained by the Global CMT (GCMT) Project. The seismic moments and focal mechanisms of these catalogues were highly consistent with each other, but we found systematic differences between the catalogues in the source centroid locations of earthquakes off Sumatra. The InaCMT source centroid locations were closer to the hypocenter locations in the Preliminary Determination of Earthquakes (PDE) of the U.S. Geological Survey compared to those of GCMT. The systematic deviations in the GCMT source centroid locations may mainly reflect insufficient azimuthal coverage of the stations used for the inversions as well as uncertainties in the Earth model. Using the InaCMT catalogue, we investigated seismic activity related to the off Bengkulu seismic sequence on 12 September 2007 ( Mw = 8.3, 7.9, and 6.8), southwest of Sumatra, and the earthquakes northwest of the island of New Guinea on 3 January 2009 ( Mw = 7.7 and 7.4). In the aftershock activity of the 2007 off Bengkulu seismic sequence, we found that shallow earthquakes were aligned along the eastern coast of Siberut Island, located between the Sunda trench and Sumatra. These earthquakes may have occurred along the Mentawai fault or another unknown fault. The focal mechanisms of the earthquakes were dominantly reverse slip, although the Mentawai fault has been considered to be a strike-slip fault. Shallow large earthquakes along this fault may cause damage above the source region and generate large tsunamis. We found that the 2009 earthquakes northwest of New Guinea occurred along the Manokwari trough and that the aftershocks were aligned along a plane dipping about 30° to the south, indicating that the Pacific and/or Philippine Sea plate subducts below the Australian plate at the Manokwari trough. The InaCMT catalogue enables us to perform detailed analyses of seismic activity in and around Indonesia, which contributes to better understanding of tectonic features and potential seismic and tsunami hazards in Indonesia as well as the coastal regions of the Pacific and Indian Oceans.

Nakano, M.; Yamashina, T.; Kumagai, H.; Inoue, H.; Sunarjo

2010-12-01

51

Comparing the performance of open loop centroiding techniques in the Raven MOAO system  

Science.gov (United States)

Raven is a multi-object adaptive optics (MOAO) demonstrator that will be mounted on the NIR Nasmyth platform of the Subaru telescope in May, 2014. Raven can use three open-loop NGS WFSs and an on-axis LGS WFS to control DMs in two separate science pick-off arms. Centroiding in open loop AO systems like Raven is more difficult than in closed loop AO systems because the Shack-Hartmann spots will not be driven to the same spot on a detector. Rather the spots can fall on any combination of pixels because the WFSs need to have sufficient dynamic range to measure the full turbulence. In this paper, we compare correlation and thresholded center of gravity (tCOG) centroiding methods in simulation, with Raven using its calibration unit, and on-sky. Each method has its own advantages. Correlation centroiding is superior to tCOG centroiding for faint NGSs and for extended sources (Raven open loop WFSs do not contain ADCs so spots will become elongated). We expect that correlation centroiding will push the limiting magnitude of Raven NGSs fainter by roughly one magnitude. Correlation centroiding is computationally more intensive, however, and actually will limit Raven's sampling rate for shorter integrations. Therefore, for bright stars with sufficiently high signal-to-noise, Raven can be run significantly faster and with superior performance using the tCOG method. Here we quantify both the performance and timing differences of these two centroiding methods in simulation, in the lab and on sky using Raven.

Andersen, David R.; Bradley, Colin; Gamroth, Darryl; Kerley, Dan; Lardière, Olivier; Véran, Jean-Pierre

2014-08-01

52

ASTROMETRIC IMAGE CENTROID DISPLACEMENTS DUE TO GRAVITATIONAL MICROLENSING BY THE ELLIS WORMHOLE  

International Nuclear Information System (INIS)

Continuing work initiated in an earlier publication, we study the gravitational microlensing effects of the Ellis wormhole in the weak-field limit. First, we find a suitable coordinate transformation, such that the lens equation and analytic expressions of the lensed image positions can become much simpler. Second, we prove that two images always appear for the weak-field lens by the Ellis wormhole. By using these analytic results, we discuss astrometric image centroid displacements due to gravitational microlensing by the Ellis wormhole. The astrometric image centroid trajectory by the Ellis wormhole is different from the standard one by a spherical lensing object that is expressed by the Schwarzschild metric. The anomalous shift of the image centroid by the Ellis wormhole lens is smaller than that by the Schwarzschild lens, provided that the impact parameter and the Einstein ring radius are the same. Therefore, the lensed image centroid by the Ellis wormhole moves slower. Such a difference, although it is very small, will be, in principle, applicable for detecting or constraining the Ellis wormhole by using future high-precision astrometry observations. In particular, the image centroid position gives us additional information, so that the parameter degeneracy existing in photometric microlensing can be partially broken. The anomalous shift reaches the order of a few micro arcseconds, if our galaxy hosts a wormhole with throat radius larger than 105 km. When the source moves tangentially to the Einstein ring, for instance, the maximum position shift of the image centroid by the Ellis wormhole is 0.18 normalized by the Einstein ring radius. For the same source trajectory, the maximum difference between the centroid displacement by the Ellis wormhole lens and that by the Schwarzschild one with the same Einstein ring radius is -0.16 in the units of the Einstein radius, where the negative means that the astrometric displacement by the Ellis wormhole lens is smaller than that by the Schwarzschild one.

53

Centroid Velocity Statistics of Molecular Clouds  

CERN Document Server

We compute structure functions and Fourier spectra of 2D centroid velocity (CV) maps in order to study the gas dynamics of typical molecular clouds (MCs) in numerical simulations. We account for a simplified treatment of time-dependent chemistry and the non-isothermal nature of the gas and use a 3D radiative transfer tool to model the CO line emission in a post-processing step. We perform simulations using three different initial mean number densities of n_0 = 30, 100 and 300 cm^{-3} to span a range of typical values for dense gas clouds in the solar neighbourhood. We compute slopes of the centroid velocity increment structure functions (CVISF) and of Fourier spectra for different chemical components: the total density, H2 number density, 12CO number density as well as the integrated intensity of 12CO (J=1-0) and 13CO (J=1-0). We show that optical depth effects can significantly affect the slopes derived for the CVISF, which also leads to different scaling properties for the Fourier spectra. The slopes of CVI...

Bertram, Erik; Shetty, Rahul; Glover, Simon C O; Klessen, Ralf S

2014-01-01

54

Measurement of centroid trajectory of Dragon-I electron beam  

International Nuclear Information System (INIS)

The control of the electron beam in an intense current linear induction accelerator (LIA) is very important. The center position of the electron beam and the beam profile are two important parameters which should be measured accurately. The setup of a time-resolved measurement system and a data processing method for determining the beam center position are introduced for the purpose of obtaining Dragon-I electron beam trajectory including beam profile. The actual results show that the centroid position error can be controlled in one to two pixels. the time-resolved beam centroid trajectory of Dragon-I (18.5 MeV, 2 kA, 90 ns) is obtained recently in 10 ns interval, 3 ns exposure time with a multi-frame gated camera. The results show that the screw movement of the electron beam is mainly limited in an area with a radius of 0.5 mm and the time-resolved diameters of the beam are 8.4 mm, 8.8 mm, 8.5 mm, 9.3 mm and 7.6 mm. These results have provided a very important support to several research areas such as beam trajectory tuning and beam transmission. (authors)

55

Interstellar cloud structure: The statistics of centroid velocities  

CERN Document Server

The investigation of the statistical properties of maps of line centroids has been used for almost 50 years, but there is still no general agreement on their interpretation. We try to quantify which properties of underlying turbulent velocity fields can be derived from centroid velocity maps, and we test conditions under which the scaling behaviour of the centroid velocities matches the scaling of the three-dimensional velocity field. Using fractal cloud models we study systematically the relation between three-dimensional density and velocity fields and the statistical properties of the produced line centroid maps. We put special attention to cases with large density fluctuations resembling supersonic interstellar turbulence. Starting from the Delta-variance analysis we derive a new tool to compute the scaling behaviour of the three-dimensional velocity field from observed intensity and centroid velocity maps. We provide two criteria to decide whether the information from the centroid velocities directly ref...

Ossenkopf, V; Lazarian, A; Stutzki, J

2006-01-01

56

An Improved Centroid Algorithm in Wireless Sensor Network  

Directory of Open Access Journals (Sweden)

Full Text Available Due to the anisotropic network, the distribution of nodes is completely random, network topology is not uniform, through the centroid algorithm there are some errors between estimated position and actual position of nodes, "cluster effect" error is prone to made in the positioning process. In order to overcome the positioning error resulting, a modified centroid algorithm is proposed that adds the stage of a correction of node estimated position on the basis of the traditional centroid algorithm positioning completion.

Siwei Peng

2013-01-01

57

Visualization Method for Finding Critical Care Factors in Variance Analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present a novel visualization method for finding care factors in variance analysis. The analysis has two stages: first stage enables users to extract a significant variance, and second stage enables users to find out a critical care factors of the variance. The analysis has been validated by using synthetically created inpatient care processes. It was found that the method is efficient in improving clinical pathways.

Yui, Shuntaro; Bito, Yoshitaka; Obara, Kiyohiro; Kamiyama, Takuya; Seto, Kumiko; Ban, Hideyuki; Hashizume, Akihide; Haga, Masashi; Oka, Yuji

2006-01-01

58

Energy Centroids in the presence of random interactions  

CERN Document Server

In this paper we study energy centroids such as those with fixed spin and isospin, those with fixed irreducible representations for bosons, in the presence of random two-body and/or three-body interactions. Our results show that regularities of energy centroids of fixed spin states reported in earlier works are more robust than expected.

Zhao, Y M; Yoshida, N; Ogawa, K; Yoshinaga, N; Kota, V K B

2005-01-01

59

A new method for finding vacua in string phenomenology  

Energy Technology Data Exchange (ETDEWEB)

One of the central problems of string-phenomenology is to find stable vacua in the four dimensional effective theories which result from compactification. We present an algorithmic method to find all of the vacua of any given string-phenomenological system in a huge class. In particular, this paper reviews and then extends hep-th/0606122 to include various nonperturbative effects. These include gaugino condensation and instantonic contributions to the superpotential. (authors)

Gray, James [Institut d' Astrophysique de Paris and APC, Universite de Paris 7, 98 bis, Bd. Arago 75014, Paris (France); He, Yang-Hui [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom)]|[Merton College, Oxford, OX1 4JD and Mathematical Institute, Oxford University, Oxford (United Kingdom); Ilderton, Anton [School of Mathematics and Statistics, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Lukas, Andre [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom)

2007-05-15

60

A new method for finding vacua in string phenomenology  

International Nuclear Information System (INIS)

One of the central problems of string-phenomenology is to find stable vacua in the four dimensional effective theories which result from compactification. We present an algorithmic method to find all of the vacua of any given string-phenomenological system in a huge class. In particular, this paper reviews and then extends hep-th/0606122 to include various non-perturbative effects. These include gaugino condensation and instantonic contributions to the superpotential

 
 
 
 
61

A new method for finding vacua in string phenomenology  

International Nuclear Information System (INIS)

One of the central problems of string-phenomenology is to find stable vacua in the four dimensional effective theories which result from compactification. We present an algorithmic method to find all of the vacua of any given string-phenomenological system in a huge class. In particular, this paper reviews and then extends hep-th/0606122 to include various nonperturbative effects. These include gaugino condensation and instantonic contributions to the superpotential. (authors)

62

A New Method for Finding Vacua in String Phenomenology  

CERN Document Server

One of the central problems of string-phenomenology is to find stable vacua in the four dimensional effective theories which result from compactification. We present an algorithmic method to find all of the vacua of any given string-phenomenological system in a huge class. In particular, this paper reviews and then extends hep-th/0606122 to include various non-perturbative effects. These include gaugino condensation and instantonic contributions to the superpotential.

Gray, J; Ilderton, A; Lukas, A; Gray, James; He, Yang-Hui; Ilderton, Anton; Lukas, Andre

2007-01-01

63

Transverse centroid oscillations in solenoidially focused beam transport lattices  

International Nuclear Information System (INIS)

Linear equations of motion are derived that describe small-amplitude centroid oscillations induced by displacement and rotational misalignments of the focusing solenoids in the transport lattice, dipole steering elements, and initial centroid offset errors. These equations are analyzed in a local rotating Larmor frame to derive complex-variable 'alignment functions' and 'bending functions' that efficiently describe the characteristics of the centroid oscillations induced by mechanical misalignments of the solenoids and dipole steering elements. The alignment and bending functions depend only on properties of the ideal lattice in the absence of errors and steering and have associated expansion amplitudes set by the misalignments and steering fields. Applications of this formulation are presented for statistical analysis of centroid deviations, calculation of actual lattice misalignments from centroid measurements, and optimal beam steering

64

Feature selection and nearest centroid classification for protein mass spectrometry  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The use of mass spectrometry as a proteomics tool is poised to revolutionize early disease diagnosis and biomarker identification. Unfortunately, before standard supervised classification algorithms can be employed, the "curse of dimensionality" needs to be solved. Due to the sheer amount of information contained within the mass spectra, most standard machine learning techniques cannot be directly applied. Instead, feature selection techniques are used to first reduce the dimensionality of the input space and thus enable the subsequent use of classification algorithms. This paper examines feature selection techniques for proteomic mass spectrometry. Results This study examines the performance of the nearest centroid classifier coupled with the following feature selection algorithms. Student-t test, Kolmogorov-Smirnov test, and the P-test are univariate statistics used for filter-based feature ranking. From the wrapper approaches we tested sequential forward selection and a modified version of sequential backward selection. Embedded approaches included shrunken nearest centroid and a novel version of boosting based feature selection we developed. In addition, we tested several dimensionality reduction approaches, namely principal component analysis and principal component analysis coupled with linear discriminant analysis. To fairly assess each algorithm, evaluation was done using stratified cross validation with an internal leave-one-out cross-validation loop for automated feature selection. Comprehensive experiments, conducted on five popular cancer data sets, revealed that the less advocated sequential forward selection and boosted feature selection algorithms produce the most consistent results across all data sets. In contrast, the state-of-the-art performance reported on isolated data sets for several of the studied algorithms, does not hold across all data sets. Conclusion This study tested a number of popular feature selection methods using the nearest centroid classifier and found that several reportedly state-of-the-art algorithms in fact perform rather poorly when tested via stratified cross-validation. The revealed inconsistencies provide clear evidence that algorithm evaluation should be performed on several data sets using a consistent (i.e., non-randomized, stratified cross-validation procedure in order for the conclusions to be statistically sound.

Levner Ilya

2005-03-01

65

JASMINE Project --Instrument Design and Centroiding Experiment--  

Science.gov (United States)

JASMINE is the acronym of the Japan Astrometry Satellite Mission for INfrared z-band 0 9 micron Exploration and is planned to be launched around 2015 The main objective of JASMINE is to study the fundamental structure and evolution of the Milky Way Galaxy Another important objective is to investigate stellar physics In order to accomplish these objectives JASMINE will measure trigonometric parallaxes positions and proper motions of about ten million stars during the observational program with the precision of 10 microarcsec at z 14mag We present the instrument design of JASMINE optics detectors etc and techniques for estimating the centroiding of satar images to accomplish the objectives In order to obtain measurements of astrometric parameters with high accuracy the optics with a long focal length and a wide focal plane is requested The Korsch system 3-mirror system is one of the convincing models However the center of the field is totally vignetted because of the fold mirror Therefore we consider the improved Korsch system in which the center of the field is not vignetted We obtain the diffraction limited optical design with small distortion We place dozens of CCD arrays with high quantum efficiency at z-band on the focal plane This new type of detectors is now being developed mainly at National Astronomical Observatory of Japan In order to accomplish the objective we must estimate positions of star images on the CCD array with sub-pixel accuracy Therefore we need a technique to obtain precise positions of star

Yano, T.; Gouda, N.; Kobayashi, Y.; Yamada, Y.; Jasmine Working Group

66

Biased gradient squared descent saddle point finding method  

Science.gov (United States)

The harmonic approximation to transition state theory simplifies the problem of calculating a chemical reaction rate to identifying relevant low energy saddle points in a chemical system. Here, we present a saddle point finding method which does not require knowledge of specific product states. In the method, the potential energy landscape is transformed into the square of the gradient, which converts all critical points of the original potential energy surface into global minima. A biasing term is added to the gradient squared landscape to stabilize the low energy saddle points near a minimum of interest, and destabilize other critical points. We demonstrate that this method is competitive with the dimer min-mode following method in terms of the number of force evaluations required to find a set of low-energy saddle points around a reactant minimum.

Duncan, Juliana; Wu, Qiliang; Promislow, Keith; Henkelman, Graeme

2014-05-01

67

Biased gradient squared descent saddle point finding method.  

Science.gov (United States)

The harmonic approximation to transition state theory simplifies the problem of calculating a chemical reaction rate to identifying relevant low energy saddle points in a chemical system. Here, we present a saddle point finding method which does not require knowledge of specific product states. In the method, the potential energy landscape is transformed into the square of the gradient, which converts all critical points of the original potential energy surface into global minima. A biasing term is added to the gradient squared landscape to stabilize the low energy saddle points near a minimum of interest, and destabilize other critical points. We demonstrate that this method is competitive with the dimer min-mode following method in terms of the number of force evaluations required to find a set of low-energy saddle points around a reactant minimum. PMID:24852525

Duncan, Juliana; Wu, Qiliang; Promislow, Keith; Henkelman, Graeme

2014-05-21

68

Path finding methods accounting for stoichiometry in metabolic networks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Graph-based methods have been widely used for the analysis of biological networks. Their application to metabolic networks has been much discussed, in particular noting that an important weakness in such methods is that reaction stoichiometry is neglected. In this study, we show that reaction stoichiometry can be incorporated into path-finding approaches via mixed-integer linear programming. This major advance at the modeling level results in improved prediction of topological and functional ...

Pey, Jon; Prada, Joaqui?n; Beasley, John E.; Planes, Francisco J.

2011-01-01

69

Astrometric Image Centroid Displacements due to Gravitational Microlensing by the Ellis Wormhole  

CERN Document Server

Continuing work initiated in an earlier publication (Abe, ApJ, 725 (2010) 787), we study the gravitational microlensing effects of the Ellis wormhole in the weak-field limit. First, we find a suitable coordinate transformation, such that the lens equation and analytic expressions of the lensed image positions can become much simpler than the previous ones. Second, we prove that two images always appear for the weak-field lens by the Ellis wormhole. By using these analytic results, we discuss astrometric image centroid displacements due to gravitational microlensing by the Ellis wormhole. The astrometric image centroid trajectory by the Ellis wormhole is different from the standard one by a spherical lensing object that is expressed by the Schwarzschild metric. The anomalous shift of the image centroid by the Ellis wormhole lens is smaller than that by the Schwarzschild lens, provided that the impact parameter and the Einstein ring radius are the same. Therefore, the lensed image centroid by the Ellis wormhole...

Toki, Yukiharu; Asada, Hideki; Abe, Fumio

2011-01-01

70

Computed tomographic methods and findings in adenomyomatosis of the gallbladder  

International Nuclear Information System (INIS)

Objective: To describe the characteristic CT imaging of adenomyomatosis of gallbladder and to improve the diagnostic knowledge of the disease. Methods: Eleven (5 males and 6 females, mean age = 43 years) patients with adenomyomatosis of gallbladder (4 diffuse, 2 segmental, and 5 fundal) confirmed by histopathology and performed by CT examination including plain, dynamic or multiphase enhancement and/or oral chole-graphic agent were reviewed. Results: Correct diagnosis was made in 7 of 11 patients (3 diffuse, 1 segmental, and 3 fundal). CT findings included segmental or diffuse gallbladder wall thickening in the involved area, associated with well defined and regular borders at both of the inner and outer layers. Significant CT findings of this entity were marked enhancement of wall layers during triphase contrast CT scanning, especially at delayed scans. Rokitansky-Aschoff sinuses were clearly shown by CT, Presenting as characteristic 'aureola' sign, when performed with application of a chole-graphic agent. Conclusion: Understanding the CT findings and using the optimal methods, the authors can use CT scan as a valuable method to help make the diagnosis in most cases of adenomyomatosis

71

Optimality Driven Nearest Centroid Classification from Genomic Data  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nearest-centroid classifiers have recently been successfully employed in high-dimensional applications, such as in genomics. A necessary step when building a classifier for high-dimensional data is feature selection. Feature selection is frequently carried out by computing univariate scores for each feature individually, without consideration for how a subset of features performs as a whole. We introduce a new feature selection approach for high-dimensional nearest centroid classifiers that i...

Dabney, Alan R.; Storey, John D.

2007-01-01

72

Comparison of decision tree methods for finding active objects  

CERN Document Server

The automated classification of objects from large catalogues or survey projects is an important task in many astronomical surveys. Faced with various classification algorithms, astronomers should select the method according to their requirements. Here we describe several kinds of decision trees for finding active objects by multi-wavelength data, such as REPTree, Random Tree, Decision Stump, Random Forest, J48, NBTree, AdTree. All decision tree approaches investigated are in the WEKA package. The classification performance of the methods is presented. In the process of classification by decision tree methods, the classification rules are easily obtained, moreover these rules are clear and easy to understand for astronomers. As a result, astronomers are inclined to prefer and apply them, thus know which attributes are important to discriminate celestial objects. The experimental results show that when various decision trees are applied in discriminating active objects (quasars, BL Lac objects and active galax...

Zhao, Y

2007-01-01

73

A method for finding three-dimensional magnetic skeletons  

International Nuclear Information System (INIS)

Magnetic fields are an essential component of a plasma. In many astrophysical, solar, magnetospheric, and laboratory situations the magnetic field in the plasma can be very dynamic and form highly complex structures. One approach to unraveling these structures is to determine the magnetic skeleton of the field, a set of topological features that divide the magnetic field into topologically distinct domains. In general, the features of the magnetic skeleton are difficult to locate, in particular those given by numerical experiments. In this paper, we propose a new set of tools to find the skeleton of general magnetic fields including null points, spines, separatrix surfaces, and separators. This set of tools is found to be considerably better at finding the skeleton than the currently favored methods used in magnetohydrodynamics.

74

A doubly nudged elastic band method for finding transition states.  

Science.gov (United States)

A modification of the nudged elastic band (NEB) method is presented that enables stable optimizations to be run using both the limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) quasi-Newton and slow-response quenched velocity Verlet minimizers. The performance of this new "doubly nudged" DNEB method is analyzed in conjunction with both minimizers and compared with previous NEB formulations. We find that the fastest DNEB approach (DNEB/L-BFGS) can be quicker by up to 2 orders of magnitude. Applications to permutational rearrangements of the seven-atom Lennard-Jones cluster (LJ7) and highly cooperative rearrangements of LJ38 and LJ75 are presented. We also outline an updated algorithm for constructing complicated multi-step pathways using successive DNEB runs. PMID:15268346

Trygubenko, Semen A; Wales, David J

2004-02-01

75

A Doubly Nudged Elastic Band Method for Finding Transition States  

CERN Document Server

A modification of the nudged elastic band (NEB) method is presented that enables stable optimisations to be run using both the limited-memory quasi-Newton (L-BFGS) and slow-response quenched velocity Verlet (SQVV) minimisers. The performance of this new `doubly nudged' DNEB method is analysed in conjunction with both minimisers and compared with previous NEB formulations. We find that the fastest DNEB approach (DNEB/L-BFGS) can be quicker by up to two orders of magnitude. Applications to permutational rearrangements of the seven-atom Lennard-Jones cluster (LJ7) and highly cooperative rearrangements of LJ38 and LJ75 are presented. We also outline an updated algorithm for constructing complicated multi-step pathways using successive DNEB runs.

Trygubenko, S A; Trygubenko, Semen A.; Wales, David J.

2004-01-01

76

Automatic segmentation and centroid detection of skin sensors for lung interventions  

Science.gov (United States)

Electromagnetic (EM) tracking has been recognized as a valuable tool for locating the interventional devices in procedures such as lung and liver biopsy or ablation. The advantage of this technology is its real-time connection to the 3D volumetric roadmap, i.e. CT, of a patient's anatomy while the intervention is performed. EM-based guidance requires tracking of the tip of the interventional device, transforming the location of the device onto pre-operative CT images, and superimposing the device in the 3D images to assist physicians to complete the procedure more effectively. A key requirement of this data integration is to find automatically the mapping between EM and CT coordinate systems. Thus, skin fiducial sensors are attached to patients before acquiring the pre-operative CTs. Then, those sensors can be recognized in both CT and EM coordinate systems and used calculate the transformation matrix. In this paper, to enable the EM-based navigation workflow and reduce procedural preparation time, an automatic fiducial detection method is proposed to obtain the centroids of the sensors from the pre-operative CT. The approach has been applied to 13 rabbit datasets derived from an animal study and eight human images from an observation study. The numerical results show that it is a reliable and efficient method for use in EM-guided application.

Lu, Kongkuo; Xu, Sheng; Xue, Zhong; Wong, Stephen T.

2012-02-01

77

Mixed Method Research: Instruments, Validity, Reliability and Reporting Findings  

Directory of Open Access Journals (Sweden)

Full Text Available The mixed method approaches have recently risen to prominence. The reason that more researchers are opting for these types of research is that both qualitative and quantitative data are simultaneously collected, analyzed and interpreted. In this article the main research instruments (questionnaire, interview and classroom observation usually used in the mixed method designs are presented and elaborated on. It is believed that using different types of procedures for collecting data and obtaining that information through different sources (learners, teachers, program staff, etc. can augment the validity and reliability of the data and their interpretation. Therefore, the various ways of boosting the validity and reliability of the data and instruments are delineated at length. Finally, an outline of reporting the findings in the mixed method approaches is sketched out. It is believed that this article can be useful and beneficial to the researchers in general and postgraduate students in particular who want to start or are involved in the process of conducting research.

Mohammad Zohrabi

2013-02-01

78

A method to find palindromes in nucleic acid sequences  

Science.gov (United States)

Various types of sequences in the human genome are known to play important roles in different aspects of genomic functioning. Among these sequences, palindromic nucleic acid sequences are one such type that have been studied in detail and found to influence a wide variety of genomic characteristics. For a nucleotide sequence to be considered as a palindrome, its complementary strand must read the same in the opposite direction. For example, both the strands i.e the strand going from 5' to 3' and its complementary strand from 3' to 5' must be complementary. A typical nucleotide palindromic sequence would be TATA (5' to 3') and its complimentary sequence from 3' to 5' would be ATAT. Thus, a new method has been developed using dynamic programming to fetch the palindromic nucleic acid sequences. The new method uses less memory and thereby it increases the overall speed and efficiency. The proposed method has been tested using the bacterial (3891 KB bases) and human chromosomal sequences (Chr-18: 74366 kb and Chr-Y: 25554 kb) and the computation time for finding the palindromic sequences is in milli seconds. PMID:23515654

Anjana, Ramnath; Shankar, Mani; Vaishnavi, Marthandan Kirti; Sekar, Kanagaraj

2013-01-01

79

A method to find palindromes in nucleic acid sequences.  

Science.gov (United States)

Various types of sequences in the human genome are known to play important roles in different aspects of genomic functioning. Among these sequences, palindromic nucleic acid sequences are one such type that have been studied in detail and found to influence a wide variety of genomic characteristics. For a nucleotide sequence to be considered as a palindrome, its complementary strand must read the same in the opposite direction. For example, both the strands i.e the strand going from 5' to 3' and its complementary strand from 3' to 5' must be complementary. A typical nucleotide palindromic sequence would be TATA (5' to 3') and its complimentary sequence from 3' to 5' would be ATAT. Thus, a new method has been developed using dynamic programming to fetch the palindromic nucleic acid sequences. The new method uses less memory and thereby it increases the overall speed and efficiency. The proposed method has been tested using the bacterial (3891 KB bases) and human chromosomal sequences (Chr-18: 74366 kb and Chr-Y: 25554 kb) and the computation time for finding the palindromic sequences is in milli seconds. PMID:23515654

Anjana, Ramnath; Shankar, Mani; Vaishnavi, Marthandan Kirti; Sekar, Kanagaraj

2013-01-01

80

Comparison of decision tree methods for finding active objects  

Science.gov (United States)

The automated classification of objects from large catalogs or survey projects is an important task in many astronomical surveys. Faced with various classification algorithms, astronomers should select the method according to their requirements. Here we describe several kinds of decision trees for finding active objects by multi-wavelength data, such as REPTree, Random Tree, Decision Stump, Random Forest, J48, NBTree, AdTree. All decision tree approaches investigated are in the WEKA package. The classification performance of the methods is presented. In the process of classification by decision tree methods, the classification rules are easily obtained, moreover these rules are clear and easy to understand for astronomers. As a result, astronomers are inclined to prefer and apply them, thus know which attributes are important to discriminate celestial objects. The experimental results show that when various decision trees are applied in discriminating active objects (quasars, BL Lac objects and active galaxies) from non-active objects (stars and galaxies), ADTree is the best only in terms of accuracy, Decision Stump is the best only considering speed, J48 is the optimal choice considering both accuracy and speed.

Zhao, Yongheng; Zhang, Yanxia

 
 
 
 
81

Finding and characterising WHIM structures using the luminosity density method  

CERN Document Server

We have developed a new method to approach the missing baryons problem. We assume that the missing baryons reside in a form of Warm Hot Intergalactic Medium, i.e. the WHIM. Our method consists of (a) detecting the coherent large scale structure in the spatial distribution of galaxies that traces the Cosmic Web and that in hydrodynamical simulations is associated to the WHIM, (b) map its luminosity into a galaxy luminosity density field, (c) use numerical simulations to relate the luminosity density to the density of the WHIM, (d) apply this relation to real data to trace the WHIM using the observed galaxy luminosities in the Sloan Digital Sky Survey and 2dF redshift surveys. In our application we find evidence for the WHIM along the line of sight to the Sculptor Wall, at redshifts consistent with the recently reported X-ray absorption line detections. Our indirect WHIM detection technique complements the standard method based on the detection of characteristic X-ray absorption lines, showing that the galaxy l...

Nevalainen, J; Tempel, E; Branchini, E; Roncarelli, M; Giocoli, C; Heinamaki, P; Saar, E; Bonamente, M; Einasto, M; Finoguenov, A; Kaastra, J; Lindfors, E; Nurmi, P; Ueda, Y

2014-01-01

82

Communications: On artificial frequency shifts in infrared spectra obtained from centroid molecular dynamics: Quantum liquid water  

Science.gov (United States)

Centroid molecular dynamics (CMD) is a popular method to extract approximate quantum dynamics from path integral simulations. Very recently we have shown that CMD gas phase infrared spectra exhibit significant artificial redshifts of stretching peaks, due to the so-called "curvature problem" imprinted by the effective centroid potential. Here we provide evidence that for condensed phases, and in particular for liquid water, CMD produces pronounced artificial redshifts for high-frequency vibrations such as the OH stretching band. This peculiar behavior intrinsic to the CMD method explains part of the unexpectedly large quantum redshifts of the stretching band of liquid water compared to classical frequencies, which is improved after applying a simple and rough "harmonic curvature correction."

Ivanov, Sergei D.; Witt, Alexander; Shiga, Motoyuki; Marx, Dominik

2010-01-01

83

Bias in the centroid moment tensor for central Asian earthquakes: Evidence from regional surface wave data  

International Nuclear Information System (INIS)

Surface waves recorded on the Chinese Digital Seismic Network (CDSN) station Urumqi (WMQ) are analyzed for 26 centroid moment tensor (CMT) earthquakes located within an epicentral distance of 1300 km. Applying a simple grid search method for source parameter retrieval, I obtain revised estimates of the focal depth, fault strike, and seismic moment (M0) from amplitude spectra of Love and Rayleigh waves and compare these estimates with the CMT best double-couple solutions. The comparisons show that residuals are unbiased for focal depth and fault strike, where population spreads are ±13 km and ±17 degree, respectively. On the other hand, M0 estimates are found to be biased, with CMT M0 larger than regional estimates by an average of 0.27±0.04 log units. The results for focal depth and strike are consistent with previous global and regional studies comparing independent estimates with CMT results. Recent full-waveform modeling studies for central Asian earthquakes support the findings of bias in M0 estimates. I suggest that causes for M0 bias may be related to great thicknesses of continental crust in Hindu Kush and Tien Shan regions and to data censoring practices at small magnitudes. M0:mb scaling relationships for central Asian earthquakes show better agreement with western U.S. scaling when M0 estimates determined in this study are used. copyright 1998 American Geophysical Unioopyright 1998 American Geophysical Union

84

Plasma Channel Diagnostic Based on Laser Centroid Oscillations  

Energy Technology Data Exchange (ETDEWEB)

A technique has been developed for measuring the properties of discharge-based plasma channels by monitoring the centroid location of a laser beam exiting the channel as a function of input alignment offset between the laser and the channel. The centroid position of low-intensity (<10{sup 14}Wcm{sup -2}) laser pulses focused at the input of a hydrogen-filled capillary discharge waveguide was scanned and the exit positions recorded to determine the channel shape and depth with an accuracy of a few %. In addition, accurate alignment of the laser beam through the plasma channel can be provided by minimizing laser centroid motion at the channel exit as the channel depth is scanned either by scanning the plasma density or the discharge timing. The improvement in alignment accuracy provided by this technique will be crucial for minimizing electron beam pointing errors in laser plasma accelerators.

Gonsalves, Anthony; Nakamura, Kei; Lin, Chen; Osterhoff, Jens; Shiraishi, Satomi; Schroeder, Carl; Geddes, Cameron; Toth, Csaba; Esarey, Eric; Leemans, Wim

2010-09-09

85

Plasma Channel Diagnostic Based on Laser Centroid Oscillations  

International Nuclear Information System (INIS)

A technique has been developed for measuring the properties of discharge-based plasma channels by monitoring the centroid location of a laser beam exiting the channel as a function of input alignment offset between the laser and the channel. The centroid position of low-intensity (14Wcm-2) laser pulses focused at the input of a hydrogen-filled capillary discharge waveguide was scanned and the exit positions recorded to determine the channel shape and depth with an accuracy of a few %. In addition, accurate alignment of the laser beam through the plasma channel can be provided by minimizing laser centroid motion at the channel exit as the channel depth is scanned either by scanning the plasma density or the discharge timing. The improvement in alignment accuracy provided by this technique will be crucial for minimizing electron beam pointing errors in laser plasma accelerators.

86

Extracting Ocean Surface Currents from SAR: MCC and Doppler Centroid Tracking  

Science.gov (United States)

SAR backscatter from the ocean is reduced by biogenic surface slicks and repeat observations of these slicks from spaceborne SAR instruments offers a method for studying submeso- to mesoscale ocean surface current features by observing slick advection. The Maximum Cross-Correlation (MCC) method has been used to derive ocean surface currents from tracking thermal infra-red and ocean color features in satellite imagery. In this study, the MCC algorithm is applied to a series of Envisat & ERS2 SAR 30-minute lag image pairs over the US West Coast, and results are compared with HF radar currents. One sample SAR pair processed to generate currents is shown in Fig. 1. The dark linear features are surface slicks, and their spatial shift is clear in the change detection image. Comparison with the current field from HF radar shows good overall agreement. Further Envisat-ERS2 SAR pairs over the West Coast are being processed for years 2008 and 2009 and quantitative statistical comparison of MCC SAR currents with HF radar currents will be discussed. SAR Doppler centroid tracking can estimate surface currents, though only in the across-track (XT) radial direction. Removal of satellite platform contributions from the measured Doppler spectrum results in "Doppler centroid anomaly", which is the Doppler shift due to geophysical processes: wind, waves, surface currents. Modeling is used to remove the undesired geophysical components and get an estimate of radial currents. Envisat Wide Swath Mode (WSM) intensity images are delivered with a low-resolution (~10 km) Doppler centroid grid; this grid is processed to generate radial currents, and the radials can be used to study currents at the meso- and synoptic scales. A sample comparison of Doppler centroid radials with HF radar current radials (rotated in XT-direction) over the US East Coast are shown in Fig. 2. The large scale features in both current fields are similar, but smaller-scale features in HF radar radials are not apparent in Doppler radials; this is expected, because the Doppler centroid radials have much lower resolution than the HF radar radials. More Envisat WSM Doppler radials are being processed, and they will be compared with HF radar, and with MCC SAR currents where available. Quantitative statistical comparisons of these current fields will be further discussed.; MCC SAR currents from an Envisat-ERS2 30-minute lag image pair ; Doppler centroid radial currents from an Envisat WSM Doppler centorid grid

Qazi, W. A.; Emery, W. J.; Hansen, M. W.

2012-12-01

87

r-centroids and Franck-Condon factors of the SiO molecule  

International Nuclear Information System (INIS)

The r-centroids and Franck-Condon factors for the bands of the E1?+-X1?+ and a 3PIsub(r) - X1?+ systems of the astrophysically important SiO molecule have been determined. The characteristic bands of this molecule are found in the sunspots. The Franck-Condon factors are determined by the approximate analytical method of Jarmain and Fraser. The absence of the bands in these systems is explained. (orig.)

88

Centroids and the Rapid Decay property in mapping class groups  

CERN Document Server

We study a notion of a Lipschitz, permutation-invariant "centroid" for triples of points in mapping class groups MCG(S), which satisfies a certain polynomial growth bound. A consequence (via work of Drutu-Sapir) is the Rapid Decay Property for MCG(S).

Behrstock, Jason A

2008-01-01

89

The Integration of Math and Science via Centroids.  

Science.gov (United States)

Explores the new proving of Ceva and Menelaus's results from Archimedes's Law of the Lever. Presents the geometrical construction of the weighted centroid of the gravity of finite particles along with some properties of vector representation, and sets up a related result to spatial shape. (Author/ASK)

Lee, Cheng-Shyong

1997-01-01

90

Optimizing the calculation of point source count-centroid in pixel size measurement  

International Nuclear Information System (INIS)

Purpose: Pixel size is an important parameter of gamma camera and SPECT. A number of Methods are used for its accurate measurement. In the original count-centroid method, where the image of a point source(PS) is acquired and its count-centroid calculated to represent PS position in the image, background counts are inevitable. Thus the measured count-centroid (Xm) is an approximation of the true count-centroid (Xp) of the PS, i.e. Xm=Xp+(Xb-Xp)/(1+Rp/Rb), where Rp is the net counting rate of the PS, Xb the background count-centroid and Rb the background counting rate. To get accurate measurement, Rp must be very big, which is unpractical, resulting in the variation of measured pixel size. Rp-independent calculation of PS count-centroid is desired. Methods: The proposed method attempted to eliminate the effect of the term (Xb-Xp)/(1+Rp/Rb) by bringing Xb closer to Xp and by reducing Rb. In the acquired PS image, a circular ROI was generated to enclose the PS, the pixel with the maximum count being the center of the ROI. To choose the diameter (D) of the ROI, a Gaussian count distribution was assumed for the PS, accordingly, K=I-(0.5)D/R percent of the total PS counts was in the ROI, R being the full width at half maximum of the PS count distribution. D was set to be 6*R to enclose most (K=98.4%) of the PS counts. The count-centroid of the ROI was calculated to represent Xp. The proposed method was tested in measuring the pixel size of a well-tuned SPECT, whose pixel sizize of a well-tuned SPECT, whose pixel size was estimated to be 3.02 mm according to its mechanical and electronic setting (128*128 matrix, 387 mm UFOV, ZOOM=1). For comparison, the original method, which was use in the former versions of some commercial SPECT software, was also tested. 12 PSs were prepared and their image acquired and stored. The net counting rate of the PSs increased from 10cps to 1183cps. Results: Using the proposed method, the measured pixel size (in mm) varied only between 3.00 and 3.01( mean= 3.01±0.00) as Rp increased, and the difference between the measured and estimated pixel size was < 1%. While using the original method, the measured pixel size decreased from 23.11 to 3.10 (mean= 7.07±6.35) as Rp increased, and the difference between the measured and estimated pixel size was much bigger. Conclusions: The proposed method is not only Rp-independent, but also accurate and precise. (authors)

91

First experimental results of very high accuracy centroiding measurements for the neat astrometric mission  

CERN Document Server

NEAT is an astrometric mission proposed to ESA with the objectives of detecting Earth-like exoplanets in the habitable zone of nearby solar-type stars. NEAT requires the capability to measure stellar centroids at the precision of 5e-6 pixel. Current state-of-the-art methods for centroid estimation have reached a precision of about 2e-5 pixel at two times Nyquist sampling, this was shown at the JPL by the VESTA experiment. A metrology system was used to calibrate intra and inter pixel quantum efficiency variations in order to correct pixelation errors. The European part of the NEAT consortium is building a testbed in vacuum in order to achieve 5e-6 pixel precision for the centroid estimation. The goal is to provide a proof of concept for the precision requirement of the NEAT spacecraft. In this paper we present the metrology and the pseudo stellar sources sub-systems, we present a performance model and an error budget of the experiment and we report the present status of the demonstration. Finally we also pres...

Crouzier, A; Preis, O; Henault, F; Kern, P; Martin, G; Feautrier, P; Stadler, E; Lafrasse, S; Behar, E; Saint-Pe, M; Dupont, J; Potin, S; Cara, C; Lagage, P O; Leger, A; LeDuigou, J M; Shao, M; Goullioud, R

2013-01-01

92

Centroid based Categorization Approach for Extraction of Body Sensor Network Data  

Directory of Open Access Journals (Sweden)

Full Text Available Monitoring human activities using wearable wireless sensor nodes has the potential to enable many useful applications for everyday situations. The long-term lifestyle categorization can greatly improve healthcare by gathering information about quality of life; aiding the diagnosis and tracking of certain diseases. The deployment of an automatic and computationally-efficient algorithm reduces the complexities involved in the detection and recognition of human activities in a distributed on Body sensor network server. Directory service is a useful aid human looking for information on Network Data. A directory services is a pre-categorized list of topics containing many links for each topic. However, most directory services are maintained manually now and face many drawbacks. Therefore the task of automatic categorization of new data into the topics of directory services becomes very necessary. BSN data categorization is more difficult due to a large variation of noisy information embedded in Sensor network data. This paper suggests a new Centroid based approach for Categorization for BSN data. We further introduce a new algorithm through centroid based approach for extraction of BSN data categorization and show that it achieves about more improvement over other BSN data categorization methods. Experimental results show that our proposed Centroid-based BSN data categorization algorithm achieves an approximately 13.8% improvement for BSN data categorization algorithm.

Setu Ku. Chaturvedi

2010-01-01

93

Metrology calibration and very high accuracy centroiding with the NEAT testbed  

CERN Document Server

NEAT is an astrometric mission proposed to ESA with the objectives of detecting Earth-like exoplanets in the habitable zone of nearby solar-type stars. NEAT requires the capability to measure stellar centroids at the precision of 5e-6 pixel. Current state-of-the-art methods for centroid estimation have reached a precision of about 2e-5 pixel at two times Nyquist sampling, this was shown at the JPL by the VESTA experiment. A metrology system was used to calibrate intra and inter pixel quantum efficiency variations in order to correct pixelation errors. The European part of the NEAT consortium is building a testbed in vacuum in order to achieve 5e-6 pixel precision for the centroid estimation. The goal is to provide a proof of concept for the precision requirement of the NEAT spacecraft. The testbed consists of two main sub-systems. The first one produces pseudo stars: a blackbody source is fed into a large core fiber and lights-up a pinhole mask in the object plane, which is imaged by a mirror on the CCD. The ...

Crouzier, A; Preis, O; Henault, F; Kern, P; Martin, G; Feautrier, P; Stadler, E; Lafrasse, S; Delboulbe, A; Behar, E; Saint-Pe, M; Dupont, J; Potin, S; Cara, C; Donati, M; Doumayrou, E; Lagage, P O; Léger, A; LeDuigou, J M; Shao, M; Goullioud, R

2014-01-01

94

Real time quantum dynamics preaveraged over imaginary time path integral: A formal basis for both Centroid Molecular Dynamics and Ring Polymer Molecular Dynamics  

CERN Document Server

An exact real time quantum dynamics preaveraged over imaginary time path integral is formulated for general condensed phase equilibrium ensemble. This formulation results in the well-known centroid dynamics approach upon filtering of centroid constraint, and provides a rigorous framework to understand and analyze a related quantum dynamics approximation method called ring polymer molecular dynamics. The formulation also serves as the basis for developing new kinds of quantum dynamics that utilize the cyclic nature of the imaginary time path integral.

Jang, Seogjoo

2013-01-01

95

Plasma Channel Diagnostic Based on Laser Centroid Oscillations  

Energy Technology Data Exchange (ETDEWEB)

A technique has been developed for measuring the properties of discharge-based plasma channels by monitoring the centroid location of a laser beam exiting the channel as a function of input alignment offset between the laser and the channel. Experiments were performed using low-intensity (< 1014 Wcm-2) laser pulses focused onto the entrance of a hydrogen-filled capillary discharge waveguide. Scanning the laser centroid position at the input of the channel and recording the exit position allows determination of the channel depth with an accuracy of a few percent, measurement of the transverse channel shape, and inference of the matched spot size. In addition, accurate alignment of the laser beam through the plasma channel is provided by minimizing laser centroid motion at the channel exit as the channel depth is scanned either by scanning the plasma density or the discharge timing. The improvement in alignment accuracy provided by this technique will be crucial for minimizing electron beam pointing errors in laser plasma accelerators.

Gonsalves, A.J.; Nakamura, K.; Lin, C.; Osterhoff, J.; Shiraishi, S.; Schroeder, C.B.; Geddes, C.G.R.; Toth, Cs.; Esarey, E.; Leemans, W.P.

2010-02-12

96

Modified string method for finding minimum energy path  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present an efficient algorithm for calculating the minimum energy path (MEP) and energy barriers between local minima on a multidimensional potential energy surface (PES). Such paths play a central role in the understanding of transition pathways between metastable states. Our method relies on the original formulation of the string method [Phys. Rev. B ${\\bf 66}$, 052301 (2002)], i.e. to evolve a smooth curve along a direction normal to the curve. The algorithm works by p...

Samanta, Amit; E, Weinan

2010-01-01

97

Model Independent Analysis of Beam Centroid Dynamics in Accelerators  

International Nuclear Information System (INIS)

Fundamental issues in Beam-Position-Monitor (BPM)-based beam dynamics observations are studied in this dissertation. The major topic is the Model-Independent Analysis (MIA) of beam centroid dynamics. Conventional beam dynamics analysis requires a certain machine model, which itself of ten needs to be refined by beam measurements. Instead of using any particular machine model, MIA relies on a statistical analysis of the vast amount of BPM data that often can be collected non-invasively during normal machine operation. There are two major parts in MIA. One is noise reduction and degrees-of-freedom analysis using a singular value decomposition of a BPM-data matrix, which constitutes a principal component analysis of BPM data. The other is a physical base decomposition of the BPM-data matrix based on the time structure of pulse-by-pulse beam and/or machine parameters. The combination of these two methods allows one to break the resolution limit set by individual BPMs and observe beam dynamics at more accurate levels. A physical base decomposition is particularly useful for understanding various beam dynamics issues. MIA improves observation and analysis of beam dynamics and thus leads to better understanding and control of beams in both linacs and rings. The statistical nature of MIA makes it potentially useful in other fields. Another important topic discussed in this dissertation is the measurement of a nonlinear Poincare section (one-turn) map in circular accelerators.n (one-turn) map in circular accelerators. The beam dynamics in a ring is intrinsically nonlinear. In fact, nonlinearities are a major factor that limits stability and influences the dynamics of halos. The Poincare section map plays a basic role in characterizing and analyzing such a periodic nonlinear system. Although many kinds of nonlinear beam dynamics experiments have been conducted, no direct measurement of a nonlinear map has been reported for a ring in normal operation mode. This dissertation analyzes various issues concerning map measurements and shows that it is possible to measure the Poincare section map (in terms of Taylor series) of a circular accelerator to a surprisingly high order and accuracy based on present BPM technology. MIA can overcome the inherent limit of BPM resolution. Nonlinear map measurements will advance understanding of the beam dynamics of a ring

98

Subliminal psychodynamic activation method and annihilation anxiety: preliminary findings.  

Science.gov (United States)

Research with the subliminal psychodynamic activation (SPA) method has led to improvements in subjects' functioning in a variety of areas, including but not limited to weight control, school grades, and feelings of general anxiety. In 1987, Hurvich proposed that the SPA method could be used to further the understanding of annihilation anxiety. 100 nonclinical subjects completed questionnaires pertaining to annihilation anxiety, psychological differentiation, and state anxiety and were tachistoscopically exposed to the subliminal message of symbiotic-like oneness, MOMMY AND I ARE ONE, and to control messages. Analysis showed that women with low annihilation anxiety had significantly lower state anxiety than women with high annihilation anxiety, regardless of the content of the subliminal message; results did not reach significance for men. Correlations among scores on the questionnaires also were noted. PMID:1561028

Greenberg, A C

1992-02-01

99

Comparison of statistical methods for finding network motifs.  

Science.gov (United States)

There has been much recent interest in systems biology for investigating the structure of gene regulatory systems. Such networks are often formed of specific patterns, or network motifs, that are interesting from a biological point of view. Our aim in the present paper is to compare statistical methods specifically with regard to the question of how well they can detect such motifs. One popular approach is by network analysis with Gaussian graphical models (GGMs), which are statistical models associated with undirected graphs, where vertices of the graph represent genes and edges indicate regulatory interactions. Gene expression microarray data allow us to observe the amount of mRNA simultaneously for a large number of genes p under different experimental conditions n, where p is usually much larger than n prohibiting the use of standard methods. We therefore compare the performance of a number of procedures that have been specifically designed to address this large p-small n issue: G-Lasso estimation, Neighbourhood selection, Shrinkage estimation using empirical Bayes for model selection, and PC-algorithm. We found that all approaches performed poorly on the benchmark E. coli network. Hence we systematically studied their ability to detect specific network motifs, pairs, hubs and cascades, in extensive simulations. We conclude that all methods have difficulty detecting hubs, but the PC-algorithm is most promising. PMID:24933631

Albieri, Vanna; Didelez, Vanessa

2014-08-01

100

Efficient methods for finding transition states in chemical reactions: comparison of improved dimer method and partitioned rational function optimization method.  

Science.gov (United States)

A combination of interpolation methods and local saddle-point search algorithms is probably the most efficient way of finding transition states in chemical reactions. Interpolation methods such as the growing-string method and the nudged-elastic band are able to find an approximation to the minimum-energy pathway and thereby provide a good initial guess for a transition state and imaginary mode connecting both reactant and product states. Since interpolation methods employ usually just a small number of configurations and converge slowly close to the minimum-energy pathway, local methods such as partitioned rational function optimization methods using either exact or approximate Hessians or minimum-mode-following methods such as the dimer or the Lanczos method have to be used to converge to the transition state. A modification to the original dimer method proposed by [Henkelman and Jonnson J. Chem. Phys. 111, 7010 (1999)] is presented, reducing the number of gradient calculations per cycle from six to four gradients or three gradients and one energy, and significantly improves the overall performance of the algorithm on quantum-chemical potential-energy surfaces, where forces are subject to numerical noise. A comparison is made between the dimer methods and the well-established partitioned rational function optimization methods for finding transition states after the use of interpolation methods. Results for 24 different small- to medium-sized chemical reactions covering a wide range of structural types demonstrate that the improved dimer method is an efficient alternative saddle-point search algorithm on medium-sized to large systems and is often even able to find transition states when partitioned rational function optimization methods fail to converge. PMID:16375464

Heyden, Andreas; Bell, Alexis T; Keil, Frerich J

2005-12-01

 
 
 
 
101

Esthesioneuroblastoma methods of intracranial extension: CT and MR imaging findings  

International Nuclear Information System (INIS)

Esthesioneuroblastoma (ENB) is an aggressive neuroectodermal malignancy in the upper nasal cavity with local infiltration and lymphatic or hematogenous metastasis. The purpose of this paper is to document three types of direct intracranial extensions by ENB using computed tomography (CT) and magnetic resonance imaging (MRI). Eleven patients with pathologically confirmed ENB were admitted in our hospital between December 2002 and December 2008. Their magnetic resonance (MR; n = 10) and CT (n = 8) images were retrospectively reviewed, and particular attention was paid to tumor location and extension, enhancement pattern, cervical lymph node metastasis, and Kadish stage. The majority of patients were male (8/11) with Kadish stage C tumor (10/11). Three types of direct intracranial extension by ENBs were put forward according to their MR and CT findings. The primary tumors were well-defined soft-tissue masses centered in the roof of the nasal cavity eroding into the paranasal sinuses (11/11), the contralateral nasal cavity (4/11), the cranial cavity (5/11), and the fossa orbitalis (3/11). The tumor parenchyma were hypointensity on T1-weighted images, heterogeneous hyperintensity on T2-weighted images, and isodensity or slight hyperdensity on CT images with scattered necroses (4/11) and marginal cysts(4/11). Their enhancements were significant and inhomogeneous. Cervical lymph nodes metastases were observed in four patients (4/11), but no pathologically proved distant metastasis was observed. Three types of direct intracranial extensions by ENB can be found on CT and MRI: cranio-orbital-nasal-communicating ENB, cranio-nasal-communicating ENB, and orbital-nasal-communicating ENB. (orig.)

102

Esthesioneuroblastoma methods of intracranial extension: CT and MR imaging findings  

Energy Technology Data Exchange (ETDEWEB)

Esthesioneuroblastoma (ENB) is an aggressive neuroectodermal malignancy in the upper nasal cavity with local infiltration and lymphatic or hematogenous metastasis. The purpose of this paper is to document three types of direct intracranial extensions by ENB using computed tomography (CT) and magnetic resonance imaging (MRI). Eleven patients with pathologically confirmed ENB were admitted in our hospital between December 2002 and December 2008. Their magnetic resonance (MR; n = 10) and CT (n = 8) images were retrospectively reviewed, and particular attention was paid to tumor location and extension, enhancement pattern, cervical lymph node metastasis, and Kadish stage. The majority of patients were male (8/11) with Kadish stage C tumor (10/11). Three types of direct intracranial extension by ENBs were put forward according to their MR and CT findings. The primary tumors were well-defined soft-tissue masses centered in the roof of the nasal cavity eroding into the paranasal sinuses (11/11), the contralateral nasal cavity (4/11), the cranial cavity (5/11), and the fossa orbitalis (3/11). The tumor parenchyma were hypointensity on T1-weighted images, heterogeneous hyperintensity on T2-weighted images, and isodensity or slight hyperdensity on CT images with scattered necroses (4/11) and marginal cysts(4/11). Their enhancements were significant and inhomogeneous. Cervical lymph nodes metastases were observed in four patients (4/11), but no pathologically proved distant metastasis was observed. Three types of direct intracranial extensions by ENB can be found on CT and MRI: cranio-orbital-nasal-communicating ENB, cranio-nasal-communicating ENB, and orbital-nasal-communicating ENB. (orig.)

Yu, Tian; Xu, Yi-Kai; Jia, Fei-Ge; Yang, Rui-Meng; Feng, Jie; Ye, Xiang-Hua; Qiu, Ying-Wei [Southern Medical University, Department of Medical Imaging Center, Nan Fang Hospital, Guangzhou, Guangdong (China); Li, Long [Chinese People' s Armed Police Forces, Department of Radiology, Guangdong Provincial Corps Hospital, Guangzhou (China); Duan, Gang; Wu, Yuan-Kui [Southern Medical University, Department of Radiology, Nan Fang Hospital, Guangzhou (China); Li, Hua-Yu [No. 458 Hospital of PLA, Department of Medical Imaging Center, Guangzhou (China)

2009-12-15

103

Fixed J spectral distributions in large shell model spaces. III. Fixed J quasiparticle centroids and widths  

International Nuclear Information System (INIS)

A method is developed to exactly calculate the fixed J quasiparticle centroid energies and partial widths. Some results obtained in the even-mass lead isotopes with various interactions are analysed. Fixed J quasi-particle distributions are used to predict an upper limit for the deviations between the quasiparticle approximation and the shell model results for the low-energy levels. The influence of the states with a high quasiparticle number in the low-energy region is seen to strongly depend upon the interaction. The importance of the dimensionalities and the internal widths in explaining the admixtures is stressed

104

Finding Similarities in Ancient Ceramics by EDXRF and Multivariate Methods  

International Nuclear Information System (INIS)

We have studied 39 samples of fragments from ceramic roof tiles with different stamps(Diamalas and Heraion), dated between 330 to 170 BC and found at the archaeological site of Dimales, some 30 km from the Adriatic coast. The data from these samples were compared with those obtained from 7 samples of similar objects and period with the stamp Heraion, found at the archaeological site of APOLLONIA. The samples were analyzed by energy-dispersive X -ray fluorescence(EDXRF), using of the x-ray lines of the elements to the intensity of the Compton peak. The results have been treated with diverse multivariate methods. The application of hierarchical cluster analysis and factor analysis permitted the identification of two main clusters. The first cluster is composed from the ''Heraion'' samples discovered in Apollonia, while the second comprises all the samples discovered in Dimale independent of their stamp. (authors)

105

M?bius-strip-like columnar functional connections are revealed in somato-sensory receptive field centroids  

Science.gov (United States)

Receptive fields of neurons in the forelimb region of areas 3b and 1 of primary somatosensory cortex, in cats and monkeys, were mapped using extracellular recordings obtained sequentially from nearly radial penetrations. Locations of the field centroids indicated the presence of a functional system in which cortical homotypic representations of the limb surfaces are entwined in three-dimensional Möbius-strip-like patterns of synaptic connections. Boundaries of somatosensory receptive field in nested groups irregularly overlie the centroid order, and are interpreted as arising from the superposition of learned connections upon the embryonic order. Since the theory of embryonic synaptic self-organization used to model these results was devised and earlier used to explain findings in primary visual cortex, the present findings suggest the theory may be of general application throughout cortex and may reveal a modular functional synaptic system, which, only in some parts of the cortex, and in some species, is manifest as anatomical ordering into columns.

Wright, James Joseph; Bourke, Paul David; Favorov, Oleg Vyachesslavovich

2014-01-01

106

Onychomycosis: Clinical findings, etiological agents and evaluation of laboratory methods  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this study was to identify the etiological agents in patients with suspected onychomycosis, and to carry out comparative testing of individual or combinations of tests: direct microscopy with KOH and Blankophor (BP, culturing on Sabouraud’s dextrose agar (SDA, diluted Sabouraud’s dextrose agar (D-SDA and dermatophyte test medium (DTM. From 70 nail samples (65 toenails, 5 fingernails, 46 (60.5% had at least one of five positive tests. Isolation was possible in 41, while in 5 samples the presence of fungi was observed by KOH and/or BP. Dermatophytes were most frequently isolated (80.5% where Trichophyton rubrum was predominant. Candida spp. was isolated in 9.8%, Aspergillus spp. 4.9%, Alternaria spp. 2.4% and Fusarium spp. 2.4%. Application of BP as an individual test was the most sensitive method. The combination of BP with DTM or D-SDA provides the best sensitivity and allows the identification of fungi to the species/genus level.

Dubljanin Eleonora

2014-01-01

107

Centroid-moment tensor inversions using high-rate GPS waveforms  

Science.gov (United States)

Displacement time-series recorded by Global Positioning System (GPS) receivers are a new type of near-field waveform observation of the seismic source. We have developed an inversion method which enables the recovery of an earthquake's mechanism and centroid coordinates from such data. Our approach is identical to that of the 'classical' Centroid-Moment Tensor (CMT) algorithm, except that we forward model the seismic wavefield using a method that is amenable to the efficient computation of synthetic GPS seismograms and their partial derivatives. We demonstrate the validity of our approach by calculating CMT solutions using 1 Hz GPS data for two recent earthquakes in Japan. These results are in good agreement with independently determined source models of these events. With wider availability of data, we envisage the CMT algorithm providing a tool for the systematic inversion of GPS waveforms, as is already the case for teleseismic data. Furthermore, this general inversion method could equally be applied to other near-field earthquake observations such as those made using accelerometers.

O'Toole, Thomas B.; Valentine, Andrew P.; Woodhouse, John H.

2012-10-01

108

Metrology calibration and very high accuracy centroiding with the NEAT testbed  

Science.gov (United States)

NEAT is an astrometric mission proposed to ESA with the objectives of detecting Earth-like exoplanets in the habitable zone of nearby solar-type stars. NEAT requires the capability to measure stellar centroids at the precision of 5 x 10-6 pixel. Current state-of-the-art methods for centroid estimation have reached a precision of about 2 x 10-5 pixel at two times Nyquist sampling, this was shown at the JPL by the VESTA experiment. A metrology system was used to calibrate intra and inter pixel quantum efficiency variations in order to correct pixelation errors. The European part of the NEAT consortium is building a testbed in vacuum in order to achieve 5 x 10-6 pixel precision for the centroid estimation. The goal is to provide a proof of concept for the precision requirement of the NEAT spacecraft. The testbed consists of two main sub-systems. The first one produces pseudo stars: a blackbody source is fed into a large core fiber and lights-up a pinhole mask in the object plane, which is imaged by a mirror on the CCD. The second sub-system is the metrology, it projects young fringes on the CCD. The fringes are created by two single mode fibers facing the CCD and fixed on the mirror. In this paper we present the experiments conducted and the results obtained since July 2013 when we had the first light on both the metrology and pseudo stars. We explain the data reduction procedures we used.

Crouzier, A.; Malbet, F.; Preis, O.; Henault, F.; Kern, P.; Martin, G.; Feautrier, P.; Stadler, E.; Lafrasse, S.; Delboulbe, A.; Behar, E.; Saint-Pe, M.; Dupont, J.; Potin, S.; Cara, C.; Donati, M.; Doumayrou, E.; Lagage, P. O.; Léger, A.; Le Duigou, J. M.; Shao, M.; Goullioud, R.

2014-08-01

109

Localization Algorithm based on Improved Weighted Centroid in Wireless Sensor Networks  

Directory of Open Access Journals (Sweden)

Full Text Available Location technology is becoming more and more important in wireless sensor networks. The weighted centroid localization offers a fast and simple algorithm for the location equipment in wireless sensor networks. The algorithm derives from the centroid measurement and calculation device of the adjacent anchor in the average coordinate. After the analysis of the radio propagation loss model, the most appropriate log-distance distribution model is selected to simulate the signal propagation. Based on the centroid algorithm and the weighted centroid algorithm, this paper proposes an ellipse centroid localization algorithm. This algorithm makes use of ellipse’s characteristic to estimate the unknown node’s coordinate. The main idea of ellipse centroid localization algorithm is the precision control factor that can control the algorithm’s location precision. In ellipse centroid localization algorithm, node is extended as anchor in order to strengthen anchor density’s dynamic characteristic. The simulation result shows the ellipse centroid localization algorithm is more effective than the centroid algorithm and the weighted centroid precision algorithm

Shyi-Ching Liang

2014-01-01

110

User Manual and Supporting Information for Library of Codes for Centroidal Voronoi Point Placement and Associated Zeroth, First, and Second Moment Determination; TOPICAL  

International Nuclear Information System (INIS)

The theory, numerical algorithm, and user documentation are provided for a new ''Centroidal Voronoi Tessellation (CVT)'' method of filling a region of space (2D or 3D) with particles at any desired particle density. ''Clumping'' is entirely avoided and the boundary is optimally resolved. This particle placement capability is needed for any so-called ''mesh-free'' method in which physical fields are discretized via arbitrary-connectivity discrete points. CVT exploits efficient statistical methods to avoid expensive generation of Voronoi diagrams. Nevertheless, if a CVT particle's Voronoi cell were to be explicitly computed, then it would have a centroid that coincides with the particle itself and a minimized rotational moment. The CVT code provides each particle's volume and centroid, and also the rotational moment matrix needed to approximate a particle by an ellipsoid (instead of a simple sphere). DIATOM region specification is supported

111

Hartmann and Hartmann-Shack spot identification and centroid evaluation by a new efficient segmentation and thresholding algorithm  

Science.gov (United States)

In this paper, we describe a new method to identify the spots and to obtain the coordinates for the centroids from a Hartmann and Hartmann-Shack screen test when some noise and reflection errors are present using an independent dynamic thresholding method. The proposed algorithm is a robust one, working with almost no interactive operation. It proved to be good for noise removal in the presence of relatively high noise with low and uneven contrast and spot reflections. The process involves the binarization of the image through a thresholding operation. Subsequently, a data segmentation algorithm is used for spot identification. The spot identification and indexing is performed independently. Finally, the coordinates of each centroid are obtained using an appropriate masking for each spot. To test the procedure we used first synthetic images obtained from some specified functions and later we used a Hartmanngram image from a human cornea.

Hernández-Gómez, Geovanni; Malacara-Hernández, Zacarías; Malacara-Hernández, Daniel; Gómez-Vieyra, Armando

2013-11-01

112

TEST CASE GENERATION BASED ON ADAPTIVE RANDOM BORDER CENTROIDAL VORONOI TESSELLATION  

Directory of Open Access Journals (Sweden)

Full Text Available Random testing is a black box testing approach where programs are tested by generating random, independent inputs and also tested by choosing an arbitrary subset of all possible input values. Random testing is low cost and straightforward but its effectiveness is not satisfactory and it doesn’t cover the test cases properly. To increase the effectiveness of Random Testing, researchers have developed Adaptive Random Testing and Quasi-Random Testing methods which attempt to maximize the test case coverage of the input domain. Adaptive Random Border Centroidal Voronoi Tessellations (ARBCVT utilizes Centroidal Voronoi Tessellations (CVT, enhances the existing state of the test case generation techniques. Besides, the voronoi regions are uniformly departed to cover maximum test points. A novel search algorithm has been included into ARBCVT by reducing the order of computational complexity of the new approach. The ARBCVT approach may results in production of maximum coverage of test cases when compared to the test cases covered by the existing approaches which are more cost-effective at a reduced computational complexity. It is recommended that the usage of ARBCVT approach leads to the enhancement of the existing strategies within a software testing.

R.Charan

2014-03-01

113

Nano-JASMINE: cosmic radiation degradation of CCD performance and centroid detection  

Science.gov (United States)

Nano-JASMINE (NJ) is a very small astrometry satellite project led by the National Astronomical Observatory of Japan. The satellite is ready for launch, and the launch is currently scheduled for late 2013 or early 2014. The satellite is equipped with a fully depleted CCD and is expected to perform astrometry observations for stars brighter than 9 mag in the zw-band (0.6 µm-1.0 µm). Distances of stars located within 100 pc of the Sun can be determined by using annual parallax measurements. The targeted accuracy for the position determination of stars brighter than 7.5 mag is 3 mas, which is equivalent to measuring the positions of stars with an accuracy of less than one five-hundredth of the CCD pixel size. The position measurements of stars are performed by centroiding the stellar images taken by the CCD that operates in the time and delay integration mode. The degradation of charge transfer performance due to cosmic radiation damage in orbit is proved experimentally. A method is then required to compensate for the effects of performance degradation. One of the most effective ways of achieving this is to simulate observed stellar outputs, including the effect of CCD degradation, and then formulate our centroiding algorithm and evaluate the accuracies of the measurements. We report here the planned procedure to simulate the outputs of the NJ observations. We also developed a CCD performance-measuring system and present preliminary results obtained using the system.

Kobayashi, Yukiyasu; Shimura, Yuki; Niwa, Yoshito; Yano, Taihei; Gouda, Naoteru; Yamada, Yoshiyuki

2012-09-01

114

Assessing the uncertainties on seismic source parameters: Towards realistic error estimates for centroid-moment-tensor determinations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The centroid-moment-tensor (CMT) algorithm provides a straightforward, rapid method for the determination of seismic source parameters from waveform data. As such, it has found widespread application, and catalogues of CMT solutions – particularly the catalogue maintained by the Global CMT Project – are routinely used by geoscientists. However, there have been few attempts to quantify the uncertainties associated with any given CMT determination: whilst catalogues typically qu...

Valentine, A. P.; Trampert, J.

2012-01-01

115

The Schr\\"odinger formulation of the Feynman path centroid density  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present an analysis of the Feynman path centroid density that provides new insight into the correspondence between the path integral and the Schr\\"odinger formulations of statistical mechanics. The path centroid density is a central concept for several approximations (centroid molecular dynamics, quantum transition state theory, and pure quantum self-consistent harmonic approximation) that are used in path integral studies of thermodynamic and dynamical properties of quan...

Rami?rez, Rafael; Lo?pez-ciudad, Telesforo

1999-01-01

116

An improved centroid location algorithm for Infrared LED feature points  

Science.gov (United States)

The precision of centroid location for infrared LED point images is an important factor, which affects the precision of the light-pen Coordinate Measuring Machining (CMM) .In this paper, the error model using the traditional center of mass (COM) algorithm is analyzed and it is shown that there are systematic error and random error. This paper analyzes the systematic error and random error, and then adopts the Gaussian surface fitting (GSF) algorithm and weighted centre-ofgravity (WCOG) algorithm to compensate systematic errors, meanwhile it analyzes how to reduce random error. The simulation results show that the accuracy of the infrared LED point position can be enhanced from 1/ 20 pixel to 1/100 pixel using the new algorithm.

Wang, Shaoqiong; Yan, Bixi; Dong, Mingli; Wang, Jun; Sun, Peng

2013-10-01

117

A NEW METHOD FOR FINDING CORE LOCATIONS OF EXTENSIVE AIR SHOWERS  

International Nuclear Information System (INIS)

Analysis of an extensive air shower (EAS) detected by surface arrays highly depends on the determination of core locations. Here we present a new method to find the core location of an EAS that, unlike the common methods, does not depend on the lateral distribution function and uses arrival times of secondary particles. This method improves the accuracy of finding the core location of a low-energy EAS in the internal parts of an array, in comparison with common methods.

118

Simplex-centroid mixture formulation for optimised composting of kitchen waste.  

Science.gov (United States)

Composting is a good recycling method to fully utilise all the organic wastes present in kitchen waste due to its high nutritious matter within the waste. In this present study, the optimised mixture proportions of kitchen waste containing vegetable scraps (V), fish processing waste (F) and newspaper (N) or onion peels (O) were determined by applying the simplex-centroid mixture design method to achieve the desired initial moisture content and carbon-to-nitrogen (CN) ratio for effective composting process. The best mixture was at 48.5% V, 17.7% F and 33.7% N for blends with newspaper while for blends with onion peels, the mixture proportion was 44.0% V, 19.7% F and 36.2% O. The predicted responses from these mixture proportions fall in the acceptable limits of moisture content of 50% to 65% and CN ratio of 20-40 and were also validated experimentally. PMID:20624604

Abdullah, N; Chin, N L

2010-11-01

119

a Hierarchical Finite Element Method for Quantum Field Theory  

Science.gov (United States)

We study a model of scalar quantum field theory (QFT) in which spacetime is a discrete set of points obtained by repeatedly subdividing a triangle into three triangles at the centroid. By integrating out the field variable at the centroid we get a renormalized action on the original triangle. The exact renormalization map between the angles of the triangles is obtained as well. The map can be used to find the partition function in scalar field theories in a recursive manner. A fixed point of this map is the cotangent formula in Finite Element Method which is used to find the energy stored in fields on a plane due to a Laplacian.

Kar, Arnab; Moolekamp, Fred; Rajeev, S. G.

2013-10-01

120

Franck–Condon factors and r-centroids for the diatomic fluorides of germanium and silicon  

Directory of Open Access Journals (Sweden)

Full Text Available A suitable potential energy function was found by analysing the potential functions proposed by Morse, Mohammad and Rafi et al. for the A2?+–X2?3/2 and B2?+–X2?3/2 band systems of GeF and the 1?–1? band system of SiF. It was found that the potential proposed by Rafi et al. is in close agreement with the Rydberg–Klein–Rees (R–K–R potential. Using this potential, the wave functions were evaluated by the Wentzel–Kramer–Brillouin (W–K–B method. The Franck–Condon factors and r-centroids were computed by a numerical integration technique. The results are compared with available theoretical values. The intensities of the various bands were investigated.

S. KANAGAPRABHA

2008-05-01

 
 
 
 
121

Neutron radiography with sub-15 ?m resolution through event centroiding  

International Nuclear Information System (INIS)

Conversion of thermal and cold neutrons into a strong ?1 ns electron pulse with an absolute neutron detection efficiency as high as 50–70% makes detectors with 10B-doped Microchannel Plates (MCPs) very attractive for neutron radiography and microtomography applications. The subsequent signal amplification preserves the location of the event within the MCP pore (typically 6–10 ?m in diameter), providing the possibility to perform neutron counting with high spatial resolution. Different event centroiding techniques of the charge landing on a patterned anode enable accurate reconstruction of the neutron position, provided the charge footprints do not overlap within the time required for event processing. The new fast 2×2 Timepix readout with >1.2 kHz frame rates provides the unique possibility to detect neutrons with sub-15 ?m resolution at several MHz/cm2 counting rates. The results of high resolution neutron radiography experiments presented in this paper, demonstrate the sub-15 ?m resolution capability of our detection system. The high degree of collimation and cold spectrum of ICON and BOA beamlines combined with the high spatial resolution and detection efficiency of MCP-Timepix detectors are crucial for high contrast neutron radiography and microtomography with high spatial resolution. The next generation of Timepix electronics with sparsified readout should enable counting rates in excess of 107 n/cm2/s taking full advantage of high beam intensity of present brightest neutron imaging facilities.

122

A New Method for Finding an Optimal Solution for Transportation Problems  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper a new method named ASM-Method is proposed for finding an optimal solution for a wide range of transportation problems, directly. A numerical illustration is established and theoptimality of the result yielded by this method is also checked. The most attractive feature of this method is that it requires very simple arithmetical and logical calculation, that’s why it is very easy even for layman to understand and use. This method will be very lucrative for those decision makers who are dealing with logistics and supply chain related issues. Because of the simplicity of this method one can easily adopt it among the existing methods.

Abdul Quddoos

2012-07-01

123

Seismotectonics of Morocco from regional centroid moment tensors  

Science.gov (United States)

We have obtained new regional centroid moment tensors (RCMTs) for 35 earthquakes occurred in Morocco and vicinity between 2008 and 2012. During this time period an unprecedented number of broadband stations (more than 100) were operating in the region, providing high-quality waveform data that were used to obtain RCMTs from waveform inversion. The main part of this dataset was composed of temporary broadband stations that were concurrently deployed in different seismic experiments (i.e. IberArray, PICASSO, Muenster, Bristol). The events analyzed in this study are moderate in size, ranging in moment magnitude Mw from 3.5 to 4.8. Their predominant mechanisms correspond to reverse and strike-slip faulting, although normal and "mixed" mechanisms are also observed. In spite of this variability in mechanism type, when analyzed in terms of the orientation of the P (compression) axes two major groups can be distinguished. The first group, corresponding to earthquakes in the Altas and NE Morocco is characterized by near-horizontal P axes oriented in an approximately NW-SE direction that coincides with the direction of convergence between Africa and Eurasia. A small clockwise rotation of the orientation of the P axes is observed from eastern Morocco to the western Atlas. The second group corresponds to earthquakes in the western Rif, that are characterized also by horizontal P axes, but oriented in a SW-NE direction, almost perpendicular to the first group. These earthquakes are part of a cluster located north of Ouezzane. The mechanisms in this second cluster are consistent with recent GPS results that show that the western Rif is moving in a SW direction with respect to the African (Nubia) plate.

Villaseñor, Antonio; el Moudnib, Lahcen; Herrmann, Robert B.; Harnafi, Mimoun

2014-05-01

124

An Inversion-Free Method for Finding Positive Definite Solution of a Rational Matrix Equation  

Science.gov (United States)

A new iterative scheme has been constructed for finding minimal solution of a rational matrix equation of the form X + A*X?1A = I. The new method is inversion-free per computing step. The convergence of the method has been studied and tested via numerical experiments. PMID:25215323

Sharifi, Mahdi; Karimi Vanani, Solat; Khaksar Haghani, Farhad; K?l?cman, Adem

2014-01-01

125

Novel Method for Finding [zeta](2[rho]) from a Product of Sines  

Science.gov (United States)

Euler gave a simple method for showing that [zeta](2)=1/1[superscript 2] + 1/2[superscript 2] + 1/3[superscript 2] + ... = [pi][superscript 2]/6. He generalized his method so as to find [zeta](4), [zeta](6), [zeta](8),.... His computations became increasingly more complex as the arguments increased. In this note we show a different generalization…

Osler, Thomas J.

2006-01-01

126

An inversion-free method for finding positive definite solution of a rational matrix equation.  

Science.gov (United States)

A new iterative scheme has been constructed for finding minimal solution of a rational matrix equation of the form X + A*X (-1) A = I. The new method is inversion-free per computing step. The convergence of the method has been studied and tested via numerical experiments. PMID:25215323

Soleymani, Fazlollah; Sharifi, Mahdi; Karimi Vanani, Solat; Khaksar Haghani, Farhad; K?l?çman, Adem

2014-01-01

127

Nonlinear force density method for the form-finding of minimal surface membrane structures  

Science.gov (United States)

We develop an alternative approach for the form-finding of the minimal surface membranes (including cable membranes) using discrete models and nonlinear force density method. Two directed weighted graphs with 3 and 4-sided regional cycles, corresponding to triangular and quadrilateral finite element meshes are introduced as computational models for the form-finding problem. The triangular graph model is closely related to the triangular computational models available in the literature whilst the quadrilateral graph uses a novel averaging approach for the form-finding of membrane structures within the context of nonlinear force density method. The viability of the mentioned discrete models for form-finding are studied through two solution methods including a fixed-point iteration method and the Newton-Raphson method with backtracking. We suggest a hybrid version of these methods as an effective solution strategy. Examples of the formation of certain well-known minimal surfaces are presented whilst the results obtained are compared and contrasted with analytical solutions in order to verify the accuracy and viability of the suggested methods.

Koohestani, K.

2014-06-01

128

Dressing transformation method for finding soliton solutions of the sinh-Gordon equation  

International Nuclear Information System (INIS)

In this paper, the establishment of the dressing transformations in the sinh-Gordon model is reconsidered. By carefully analysing the infinitesimal structures of dressing transformations, we improve the algebraic method for solving the dressing problem in the system and then lay the dressing transformation method on a firm basis. The modified dressing transformation method, which no longer contains any deductive jumps, turns out to become a powerful Hamiltonian approach to finding N-soliton solutions (N?1) of the integrable systems. (author)

129

Enhancing gibbs sampling method for motif finding in DNA with initial graph representation of sequences.  

Science.gov (United States)

Abstract Finding short patterns with residue variation in a set of sequences is still an open problem in genetics, since motif-finding techniques on DNA and protein sequences are inconclusive on real data sets and their performance varies on different species. Hence, finding new algorithms and evolving established methods are vital to further understanding of genome properties and the mechanisms of protein development. In this work, we present an approach to finding functional motifs in DNA sequences in connection to Gibbs sampling method. Starting points in the search space are partly determined via graphical representation of input sequences opposed to completely random initial points with the standard Gibbs sampling. Our algorithm is evaluated on synthetic as well as on real data sets by using several statistics, such as sensitivity, positive predictive value, specificity, performance, and correlation coefficient. Additionally, a comparison between our algorithm and the basic standard Gibbs sampling algorithm is made to show improvement in accuracy, repeatability, and performance. PMID:25121709

Stepan?i?, Ziva

2014-10-01

130

A New Method for Finding the Thevenin and Norton Equivalent Circuits  

Directory of Open Access Journals (Sweden)

Full Text Available The paper presents a new pedagogical method for finding the Thevenin and Norton equivalent circuits of a linear electric circuit (LEC at the n-different pairs of terminals simultaneously, regardless of the circuit topology and complexity. The proposed method is appropriate for undergraduate electrical and electronic engineering students leading to straightforward solutions, mostly arrived at by inspection, so that it can be regarded as a simple and innovative calculation tool for Thevenin equivalents. Furthermore, the method is easily adapted to computer implementation. Examples illustrating the method’s scientific and pedagogical reliability, as well as real test results and statistically-sound data assessing its functionality are provided.

George E. Chatzarakis

2010-05-01

131

Nudged-elastic band method with two climbing images: finding transition states in complex energy landscapes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The nudged-elastic band (NEB) method is modified with concomitant two climbing images (C2-NEB) to find a transition state (TS) in complex energy landscapes, such as those with serpentine minimal energy path (MEP). If a single climbing image (C1-NEB) successfully finds the TS, C2-NEB finds it with higher stability and accuracy. However, C2-NEB is suitable for more complex cases, where C1-NEB misses the TS because the MEP and NEB directions near the saddle point are different....

Zarkevich, Nikolai A.; Johnson, Duane D.

2014-01-01

132

A trilinear method for finding null points in a three-dimensional vector space  

International Nuclear Information System (INIS)

Null points are important locations in vector fields, such as a magnetic field. A new technique (a trilinear method for finding null points) is presented for finding null points over a large grid of points, such as those derived from a numerical experiment. The method was designed so that the null points found would agree with any field lines traced using the commonly used trilinear interpolation. It is split into three parts: reduction, analysis, and positioning, which, when combined, provide an efficient means of locating null points to a user-defined subgrid accuracy. We compare the results of the trilinear method with that of a method based on the Poincare index, and discuss the accuracy and limitations of both methods

133

A Computer Program to Create a Population with Any Desired Centroid and Covariance Matrix  

Science.gov (United States)

A Computer program written in FORTRAN IV is presented which will create a population of desired size with marginally normal score vectors manifesting any desired centroid and covariance matrix. Uses and documentation are provided. (Author)

Morris, John D.

1975-01-01

134

Empirical Centroid Fictitious Play: An Approach For Distributed Learning In Multi-Agent Games  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper is concerned with distributed learning in large-scale games. The well-known fictitious play (FP) algorithm is addressed, which, despite theoretical convergence results, might be impractical to implement in large-scale settings due to intense computation and communication requirements. An adaptation of the FP algorithm, designated as the empirical centroid fictitious play (ECFP), is presented. In ECFP players respond to the centroid of all players' actions rather th...

Swenson, Brian; Kar, Soummya; Xavier, Joao

2013-01-01

135

The method of geometric progression for finding a minimum of unimodal functions  

Energy Technology Data Exchange (ETDEWEB)

An asymptotically optimal method for finding a minimal point x{sup *} for a function f(x) {element_of} C{sup 2}, unimodal on an interval [a{sub k},b{sub k}] is proposed. This method partitions the intervals {delta}{sub k} = b{sub k} - a{sub k}, k = 1, 2, {hor_ellipsis}, and locates x{sup *} by means of a decreasing geometric progression. 1 ref., 1 fig., 2 tabs.

Abdukhamidov, A.U. [Samarkand Univ. (Russian Federation)

1994-06-05

136

Nudged-elastic band method with two climbing images: finding transition states in complex energy landscapes  

CERN Document Server

The nudged-elastic band (NEB) method is modified with concomitant two climbing images (C2-NEB) to find a transition state (TS) in complex energy landscapes, such as those with serpentine minimal energy path (MEP). If a single climbing image (C1-NEB) successfully finds the TS, C2-NEB finds it with higher stability and accuracy. However, C2-NEB is suitable for more complex cases, where C1-NEB misses the TS because the MEP and NEB directions near the saddle point are different. Generally, C2-NEB not only finds the TS but guarantees that the climbing images approach it from the opposite sides along the MEP, and it estimates accuracy from the three images: the highest-energy one and its climbing neighbors. C2-NEB is suitable for fixed-cell NEB and the generalized solid-state NEB (SS-NEB).

Zarkevich, Nikolai A

2014-01-01

137

Error-finding and error-correcting methods for the start-up of the SLC  

International Nuclear Information System (INIS)

During the commissioning of an accelerator, storage ring, or beam transfer line, one of the important tasks of an accelertor physicist is to check the first-order optics of the beam line and to look for errors in the system. Conceptually, it is important to distinguish between techniques for finding the machine errors that are the cause of the problem and techniques for correcting the beam errors that are the result of the machine errors. In this paper we will limit our presentation to certain applications of these two methods for finding or correcting beam-focus errors and beam-kick errors that affect the profile and trajectory of the beam respectively. Many of these methods have been used successfully in the commissioning of SLC systems. In order not to waste expensive beam time we have developed and used a beam-line simulator to test the ideas that have not been tested experimentally. To save valuable physicist's time we have further automated the beam-kick error-finding procedures by adopting methods from the field of artificial intelligence to develop a prototype expert system. Our experience with this prototype has demonstrated the usefulness of expert systems in solving accelerator control problems. The expert system is able to find the same solutions as an expert physicist but in a more systematic fashion. The methods used in these procedures and some of the recent applications will be described in this paper

138

Research off Limits and Underground: Street Corner Methods for Finding Invisible Students  

Science.gov (United States)

This paper investigates research methods for studies of school drop-outs and push-outs, populations that are very difficult to find since they no longer have an institutional affiliation. The work argues that street corner research, which was in favor among the early urban researchers of the Chicago school, may have a renewed role in these…

Simmons, Lizbet

2007-01-01

139

A von Neumann Alternating Method for Finding Common Solutions to Variational Inequalities  

CERN Document Server

Modifying von Neumann's alternating projections algorithm, we obtain an alternating method for solving the recently introduced Common Solutions to Variational Inequalities Problem (CSVIP). For simplicity, we mainly confine our attention to the two-set CSVIP, which entails finding common solutions to two unrelated variational inequalities in Hilbert space.

Censor, Yair; Reich, Simeon

2012-01-01

140

A new exhaustive method and strategy for finding motifs in ChIP-enriched regions.  

Science.gov (United States)

ChIP-seq, which combines chromatin immunoprecipitation (ChIP) with next-generation parallel sequencing, allows for the genome-wide identification of protein-DNA interactions. This technology poses new challenges for the development of novel motif-finding algorithms and methods for determining exact protein-DNA binding sites from ChIP-enriched sequencing data. State-of-the-art heuristic, exhaustive search algorithms have limited application for the identification of short (l, d) motifs (l ? 10, d ? 2) contained in ChIP-enriched regions. In this work we have developed a more powerful exhaustive method (FMotif) for finding long (l, d) motifs in DNA sequences. In conjunction with our method, we have adopted a simple ChIP-enriched sampling strategy for finding these motifs in large-scale ChIP-enriched regions. Empirical studies on synthetic samples and applications using several ChIP data sets including 16 TF (transcription factor) ChIP-seq data sets and five TF ChIP-exo data sets have demonstrated that our proposed method is capable of finding these motifs with high efficiency and accuracy. The source code for FMotif is available at http://211.71.76.45/FMotif/. PMID:24475069

Jia, Caiyan; Carson, Matthew B; Wang, Yang; Lin, Youfang; Lu, Hui

2014-01-01

 
 
 
 
141

Initial data for general relativistic SPH with Centroidal Voronoi Tessellations  

CERN Document Server

In this work we present an alternative method to obtain a distribution of particles over an hyper surface, such that they obey a rest-mass density distribution $\\rho(x^i)$. We use density profiles that can be written as $\\rho(x^1,x^2,x^3)=\\rho(x^1) \\rho(x^2) \\rho(x^3)$ in order to be able to use them as a probability density functions. We can find the relation between the chart $x^j$ and a uniform random variable $\\bar{x}^j \\in (0,1)$, say $F(x^j)=\\bar{x}^j$. Using the inverse of this function we relate a set of $N$ arbitrary number of points inside a cube with coordinates $\\{ x^j =F^{-1}(\\bar{x}^j)\\}$ giving the position in order to get the density distribution $\\rho(x^j)$. We get some noise due to the random distribution and we can notice that each time we relax the configuration on the cube we also get a better distribution of the desired physical configuration described with $\\rho(x^j)$. This relaxation of the position of the particles in the cube has been performed a Lloyd's algorithm in 3D and we have u...

Pablo, Cruz Pérez Juan

2013-01-01

142

A regional registration method to find corresponding mass lesions in temporal mammogram pairs  

International Nuclear Information System (INIS)

In this paper we develop an automatic regional registration method to find corresponding masses on prior and current mammograms. The method contains three steps. In the first, we globally align both images. Then, for each mass lesion on the current view, we define a search area on the prior view, which is likely to contain the same mass lesion. Third, at each location in this search area we calculate a registration measure to quantify how well this location matches the mass lesion on the current view. Finally we select the best location. To determine the performance of our method we compare it to several other registration methods. On a dataset of 389 temporal mass pairs our method correctly links 82% of prior and current mass lesions, whereas other methods achieve at most 72%

143

Novas abordagens da avaliação do comportamento tático no futebol: análise do centroid e índice de dispersão / Towards a new evaluation of the football' tactical behaviour: analysis of the centroid and stretch index  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A tendência evolutiva do futebol determina as necessidades de produzir ferramentas inovadoras que aumentem substancialmente a eficiência da análise de jogo. Considerando os métodos tradicionais notacionais como limitados para a interpretação dos processos de jogo, a investigação carece de novos méto [...] dos nos quais prevaleça a análise do processo. Dessa forma, o presente trabalho propõe-se a analisar novas métricas quantitativas e automáticas de avaliação tática no futebol, nomeadamente o centroid de equipe e o índice de dispersão. Abstract in english The evolutionary tendency of the football game determines the conception of the new tools that increase the efficiency of the match analysis. The traditional notational analysis, actually, are limited to understand the true dynamic of the football match, thus the investigation lacks by new methods t [...] o understand the process and not just the product. Therefore, this work aims analyze new automatically tactical metrics, specifically the centroid and the stretch index method.

Rui Manuel, Mendes; Filipe Manuel, Clemente; Micael Santos, Couceiro; Fernando Manuel Lourenço, Martins.

2013-12-01

144

Novas abordagens da avaliação do comportamento tático no futebol: análise do centroid e índice de dispersão / Towards a new evaluation of the football' tactical behaviour: analysis of the centroid and stretch index  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A tendência evolutiva do futebol determina as necessidades de produzir ferramentas inovadoras que aumentem substancialmente a eficiência da análise de jogo. Considerando os métodos tradicionais notacionais como limitados para a interpretação dos processos de jogo, a investigação carece de novos méto [...] dos nos quais prevaleça a análise do processo. Dessa forma, o presente trabalho propõe-se a analisar novas métricas quantitativas e automáticas de avaliação tática no futebol, nomeadamente o centroid de equipe e o índice de dispersão. Abstract in english The evolutionary tendency of the football game determines the conception of the new tools that increase the efficiency of the match analysis. The traditional notational analysis, actually, are limited to understand the true dynamic of the football match, thus the investigation lacks by new methods t [...] o understand the process and not just the product. Therefore, this work aims analyze new automatically tactical metrics, specifically the centroid and the stretch index method.

Rui Manuel, Mendes; Filipe Manuel, Clemente; Micael Santos, Couceiro; Fernando Manuel Lourenço, Martins.

145

Progressive track finding coupled with track fitting by the Kalman filtering method  

International Nuclear Information System (INIS)

A progressive track finding algorithm based on the Kalman filtering method has been proposed and tested for the track reconstruction in high energy physics experiment. The algorithm starts from small track segments with fitted track parameters and weight matrices or from fitted tracks of a neighboring detector, then extends the candidate tracks by adding measured points one by one. The track parametes and weight matrices of the candidate tracks are updated at the same time of each point addition. Therefore at the end of the track finding, the track fitting is accomplished simultaneously. The main procedures and its advantages of the algorithm are presented. Its performance is briefed

146

A Tabu Search Method for Finding Minimal Multi-Homogeneous Bézout Number  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: A homotopy method has proven to be reliable for computing all of the isolated solutions of a multivariate polynomial system. The multi-homogeneous Bézout number of a polynomial system is the number of paths that one has to trace in order to compute all of its isolated solutions. Each partition of the variables corresponds to a multi-homogeneous Bézout number. It is a crucial problem to find a partition with the minimum multi-homogeneous Bézout number since the size of the space of all the partitions increases exponentially. Approach: This study presented a new method by producing the Tabu Search Method (TSM as a powerful technique for finding minimum multi-homogeneous Bézout number. Results: A comparison is made between the new method and some recent methods. It is shown that our algorithm is superior to the latter, besides being simple and efficient in the implementation. Conclusion: Furthermore the present study extended the applicability of the Tabu search method.

Hassan M.S. Bawazir

2010-01-01

147

A measure of variable planar locations anchored on the centroid of the vowel space : A sociophonetic research tool  

DEFF Research Database (Denmark)

This paper presents part of an ongoing research program which aims to apply mathematical and geometrical analytic methods to vowel formant data to enable the quantification of parameters of variation of interest to sociophoneticians. We open with an overview of recent research working towards a set of desiderata for choice of normalization algorithm(s) based on replicable procedures. We then present the principles of centroid-based normalization and account for its performance in recent road tests. In sections 4 and 5 we introduce a method that utilizes the centroid of the speaker’s vowel space as an anchor point or vertex for calculation of planar locations on formant plots, permitting quantification of the distribution of vowel tokens within the space. This information, along with details such as Euclidean distances, can then be used to precisely pinpoint the trajectories of diachronic change, for instance over a set of speakers in different age groups within a defined speech community. This has the advantage of mathematical reproducibility, and reduces the level of subjectivity in visual analyses of formant plots used in investigations of vowel variability and change in progress.

Watt, Dominic; Fabricius, Anne

2011-01-01

148

ISAR imaging of maneuvering targets based on the range centroid Doppler technique.  

Science.gov (United States)

A new inverse synthetic aperture radar (ISAR) imaging approach is presented for application in situations where the maneuverability of noncooperative target is not too severe and the Doppler variation of subechoes from scatterers can be approximated as a first-order polynomial. The proposed algorithm is referred to as the range centroid Doppler (RCD) ISAR imaging technique and is based on the stretch Keystone-Wigner transform (SKWT). The SKWT introduces a stretch weight factor containing a range of chirp rate into the autocorrelation function of each cross-range profile and uses a 1-D interpolation of the phase history which we call stretch keystone formatting. The processing simultaneously eliminates the effects of linear frequency migration for all signal components regardless of their unknown chirp rate in time-frequency plane, but not for the noise or for the cross terms. By utilizing this novel technique, clear ISAR imaging can be achieved for maneuvering targets without an exhaustive search procedure for the motion parameters. Performance comparison is carried out to evaluate the improvement of the RCD technique versus other methods such as the conventional range Doppler (RD) technique, the range instantaneous Doppler (RID) technique, and adaptive joint time-frequency (AJTF) technique. Examples provided demonstrate the effectiveness of the RCD technique with both simulated and experimental ISAR data. PMID:19775968

Lv, Xiaolei; Xing, Mengdao; Wan, Chunru; Zhang, Shouhong

2010-01-01

149

Detection of a surface breaking crack by using the centroid variations of laser ultrasonic spectrums  

International Nuclear Information System (INIS)

A laser ultrasonic system is a non-contact inspection device with a wide-band spectrum and a high spatial resolution. It provides absolute measurements of the moving distance and it can be applied to hard-to-access locations including curved or rough surfaces like in a nuclear power plant. In this paper, we have investigated the detection methods of the depth of a surface-breaking crack by using the surface wave of a laser ultrasound. The filtering function of a surface-breaking crack is a kind of a low-pass filter. The higher frequency components are more highly decreased in proportion to the crack depth. Also, the center frequency value of each ultrasound spectrum is decreased in proportion to the crack depth. We extracted the depth information of a surface-breaking crack by observing the centroid variation of the frequency spectrum. We describe the experimental results to detect the crack depth information by using the peak-to-valley values in the time domain and the center frequency values in the frequency domain.

150

New Method for Finding an Optimal Solution to Quadratic Programming Problems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this study is to present a new method for finding an optimal solution to quadratic programming problems. The principle of the method is based on calculating the value of critical point. If the critical point belongs to the set of feasible solutions, so the optimal solution to our problem is the critical point itself. If the critical point is not at in the feasible solution set, a new feasible constraint set is built by a homographic transform, in such a way that the projection of t...

Mekki, R.; Djebbar, B.; Chikhaoui, A.

2010-01-01

151

Correcting the beam centroid motion in an induction accelerator and reducing the beam breakup instability  

Science.gov (United States)

Axial beam centroid and beam breakup (BBU) measurements were conducted on an 80 ns FWHM, intense relativistic electron bunch with an injected energy of 3.8 MV and current of 2.9 kA. The intense relativistic electron bunch is accelerated and transported through a nested solenoid and ferrite induction core lattice consisting of 64 elements, exiting the accelerator with a nominal energy of 19.8 MeV. The principal objective of these experiments is to quantify the coupling of the beam centroid motion to the BBU instability and validate the theory of this coupling for the first time. Time resolved centroid measurements indicate a reduction in the BBU amplitude, ???, of 19% and a reduction in the BBU growth rate (?) of 4% by reducing beam centroid misalignments ˜50% throughout the accelerator. An investigation into the contribution of the misaligned elements is made. An alignment algorithm is presented in addition to a qualitative comparison of experimental and calculated results which include axial beam centroid oscillations, BBU amplitude, and growth with different dipole steering.

Coleman, J. E.; Ekdahl, C. A.; Moir, D. C.; Sullivan, G. W.; Crawford, M. T.

2014-09-01

152

3D Reconstruction: Novel Method for Finding of Corresponding Points using Pseudo Colors  

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Full Text Available This paper deals with the reconstruction of spatial coordinates of an arbitrary point in a scene using two images scanned by a 3D camera or two displaced cameras. Calculations are based on the perspective geom-etry. Accurate determination of corresponding points is a fundamental step in this process. The usually used methods can have a problem with points, which lie in areas without sufficient contrast. This paper describes our proposed method based on the use of the relationship between the selected points and area feature points. The proposed method finds correspondence using a set of feature points found by SURF. An algorithm is proposed and described for quick removal of false correspondences, which could ruin the correct reconstruction. The new method, which makes use of pseudo color image representation (pseudo coloring has been proposed subsequently. By means of this method it is possible to significantly increase the color contrast of the surveyed image, and therefore add more information to find the correct correspondence. Reliability of the found correspondence can be verified by reconstruction of 3D position of selected points. Executed experiments confirm our assumptions

L. Bolecek

2013-04-01

153

Initial periodontal screening and radiographic findings - A comparison of two methods to evaluate the periodontal situation  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The periodontal screening index (PSI is an element of the initial dental examination. The PSI provides information on the periodontal situation and allows a first estimation of the treatment required. The dental panoramic tomography (DPT indicates the proximal bone loss, thus also allowing conclusions on the periodontal situation. In this study, the results of both methods in determining the periodontal situation are compared. Methods The clinical examination covered DMF-T, QHI, and PSI scores at four proximal sites per tooth; the examining dentist was unaware of the radiographic finding. Based on the PSI scores, the findings were diagnosed as follows: score 0 - 2 "no periodontitis", score 3 and 4 "periodontitis". Independent of the locality and time of the clinical evaluation, two dentists examined the DPTs of the subjects. The results were classified as follows: no bone loss = "no periodontitis", and bone loss = "periodontitis". Results 112 male subjects (age 18 to 58, Ø 37.7 ± 8 years were examined. Regarding the PSI, 17 subjects were diagnosed "no periodontitis" and 95 subjects "periodontitis". According to the evaluation of the DPTs, 70 subjects were diagnosed "no periodontitis" and 42 "periodontitis". A comparison of both methods revealed that the diagnosis "no periodontitis" corresponded in 17 cases and "periodontitis" in 42 cases (53%. In 47% (53 cases the results were not congruent. The difference between both methods was statistically significant (p Conclusion The present study shows that the initial assessment of the periodontal situation significantly depends on the method of evaluation.

Hornecker Else

2011-01-01

154

Experimental determination of Philodendron melinonii and Arabidopsis thaliana tissue microstructure and geometric modeling via finite-edge centroidal Voronoi tessellation.  

Science.gov (United States)

Plant petioles and stems are hierarchical cellular structures, displaying structural features defined at multiple length scales. One or more of the intermediate hierarchical levels consists of tissues, in which the cellular distribution is quasirandom. The current work focuses on the realistic modeling of plant tissue microstructures. The finite-edge centroidal Voronoi tessellation (FECVT) is here introduced to overcome the drawbacks of the semi-infinite edges of a typical Voronoi model. FECVT can generate a realistic model of a tissue microstructure, which might have finite edges at its border, be defined by a boundary contour of any shape, and include complex heterogeneity and cellular gradients. The centroid-based Voronoi tessellation is applied to model the microstructure of the Philodendron melinonii petiole and the Arabidopsis thaliana stem, which both display intense cellular gradients. FECVT coupled with a digital image processing algorithm is implemented to capture the nonperiodic microstructures of plant tissues. The results obtained via this method satisfactorily obey the geometric, statistical, and topological laws of naturally evolved cellular solids. The predicted models are also validated by experimental data. PMID:23030958

Faisal, Tanvir R; Hristozov, Nicolay; Rey, Alejandro D; Western, Tamara L; Pasini, Damiano

2012-09-01

155

New Method for Finding an Optimal Solution to Quadratic Programming Problems  

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Full Text Available The aim of this study is to present a new method for finding an optimal solution to quadratic programming problems. The principle of the method is based on calculating the value of critical point. If the critical point belongs to the set of feasible solutions, so the optimal solution to our problem is the critical point itself. If the critical point is not at in the feasible solution set, a new feasible constraint set is built by a homographic transform, in such a way that the projection of the critical point of the objective function onto this set produces the exact solution to the problem on hand. It should be noted here that the objective function may be convex or not convex. On the other hand the search for the optimal solution is to find the hyper plane separating the convex and the critical point. Notice that one does not need to transform the quadratic problem into an equivalent linear one as in the numerical methods; the method is purely analytical and avoids the usage of initial solution. An algorithm computing the optimal solution of the concave function has given.

R. Mekki

2010-01-01

156

Parallel algorithms for planar and spherical Delaunay construction with an application to centroidal Voronoi tessellations  

Science.gov (United States)

A new algorithm, featuring overlapping domain decompositions, for the parallel construction of Delaunay and Voronoi tessellations is developed. Overlapping allows for the seamless stitching of the partial pieces of the global Delaunay tessellations constructed by individual processors. The algorithm is then modified, by the addition of stereographic projections, to handle the parallel construction of spherical Delaunay and Voronoi tessellations. The algorithms are then embedded into algorithms for the parallel construction of planar and spherical centroidal Voronoi tessellations that require multiple constructions of Delaunay tessellations. This combination of overlapping domain decompositions with stereographic projections provides a unique algorithm for the construction of spherical meshes that can be used in climate simulations. Computational tests are used to demonstrate the efficiency and scalability of the algorithms for spherical Delaunay and centroidal Voronoi tessellations. Compared to serial versions of the algorithm and to STRIPACK-based approaches, the new parallel algorithm results in speedups for the construction of spherical centroidal Voronoi tessellations and spherical Delaunay triangulations.

Jacobsen, D. W.; Gunzburger, M.; Ringler, T.; Burkardt, J.; Peterson, J.

2013-08-01

157

Comparison of methods for finding saddle points without knowledge of the final states.  

Science.gov (United States)

Within the harmonic approximation to transition state theory, the biggest challenge involved in finding the mechanism or rate of transitions is the location of the relevant saddle points on the multidimensional potential energy surface. The saddle point search is particularly challenging when the final state of the transition is not specified. In this article we report on a comparison of several methods for locating saddle points under these conditions and compare, in particular, the well-established rational function optimization (RFO) methods using either exact or approximate Hessians with the more recently proposed minimum mode following methods where only the minimum eigenvalue mode is found, either by the dimer or the Lanczos method. A test problem involving transitions in a seven-atom Pt island on a Pt(111) surface using a simple Morse pairwise potential function is used and the number of degrees of freedom varied by varying the number of movable atoms. In the full system, 175 atoms can move so 525 degrees of freedom need to be optimized to find the saddle points. For testing purposes, we have also restricted the number of movable atoms to 7 and 1. Our results indicate that if attempting to make a map of all relevant saddle points for a large system (as would be necessary when simulating the long time scale evolution of a thermal system) the minimum mode following methods are preferred. The minimum mode following methods are also more efficient when searching for the lowest saddle points in a large system, and if the force can be obtained cheaply. However, if only the lowest saddle points are sought and the calculation of the force is expensive but a good approximation for the Hessian at the starting position of the search can be obtained at low cost, then the RFO approaches employing an approximate Hessian represent the preferred choice. For small and medium sized systems where the force is expensive to calculate, the RFO approaches employing an approximate Hessian is also the more efficient, but when the force and Hessian can be obtained cheaply and only the lowest saddle points are sought the RFO approach using an exact Hessian is the better choice. These conclusions have been reached based on a comparison of the total computational effort needed to find the saddle points and the number of saddle points found for each of the methods. The RFO methods do not perform very well with respect to the latter aspect, but starting the searches further away from the initial minimum or using the hybrid RFO version presented here improves this behavior considerably in most cases. PMID:15549851

Olsen, R A; Kroes, G J; Henkelman, G; Arnaldsson, A; Jónsson, H

2004-11-22

158

Quantum imaging beyond the diffraction limit by optical centroid measurements.  

Science.gov (United States)

I propose a quantum imaging method that can beat the Rayleigh-Abbe diffraction limit and achieve de Broglie resolution without requiring a multiphoton absorber or coincidence detection. Using the same nonclassical states of light as those for quantum lithography, the proposed method requires only optical intensity measurements, followed by image postprocessing, to produce the same complex quantum interference patterns as those in quantum lithography. The method is expected to be experimentally realizable using current technology. PMID:19659073

Tsang, Mankei

2009-06-26

159

Dilation method for finding close roots of polynomials based on constrained learning neural networks  

International Nuclear Information System (INIS)

In finding roots of polynomials, often two or more roots that are close together in solution space are very difficult to be resolved by a root-finder. To solve this problem, this Letter proposes a dilation method to transform the positions of roots in space so that all roots in space are pulled further apart. As a result, those close (including complex) roots can be readily resolved efficiently by a root-finder. In addition, in this Letter a complex version of constrained learning algorithm is derived. Moreover, our previously proposing feedforward neural network (FNN) root-finder is adopted to address the root finding issue. Finally, some satisfactory results that support our approach are presented

160

Robustness of regularities for energy centroids in the presence of random interactions  

International Nuclear Information System (INIS)

In this paper we study energy centroids such as those with fixed spin and isospin and those with fixed irreducible representations for both bosons and fermions, in the presence of random two-body and/or three-body interactions. Our results show that regularities of energy centroids of fixed-spin states reported in earlier works are very robust in these more complicated cases. We suggest that these behaviors might be intrinsic features of quantum many-body systems interacting by random forces

 
 
 
 
161

Beyond Field Effect: Analysis of Shrunken Centroids in Normal Esophageal Epithelia Detects Concomitant Esophageal Adenocarcinoma  

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Full Text Available Background and Aims: Because of the extremely low neoplastic progression rate in Barrett’s esophagus, it is difficult to diagnose patients with concomitant adenocarcinoma early in their disease course. If biomarkers existed in normal squamous esophageal epithelium to identify patients with concomitant esophageal adenocarcinoma, potential applications would be far-reaching. The aim of the current study was to identify global gene expression patterns in normal esophageal epithelium capable of revealing simultaneous esophageal adenocarcinoma, even located remotely in the esophagus.Methods: Tissues comprised normal esophageal epithelia from 9 patients with esophageal adenocarcinoma, 8 patients lacking esophageal adenocarcinoma or Barrett’s, and 6 patients with Barrett’s esophagus alone. cDNA microarrays were performed, and pattern recognition in each of these subgroups was achieved using shrunken nearest centroid predictors. Results: Our method accurately discriminated normal esophageal epithelia of 8/8 patients without esophageal adenocarcinoma or Barrett’s esophagus and of 6/6 patients with Barrett’s esophagus alone from normal esophageal epithelia of 9/9 patients with Barrett’s esophagus and concomitant esophageal adenocarcinoma. Moreover, we identified genes differentially expressed between the above subgroups. Thus, based on their corresponding normal esophageal epithelia alone, our method accurately diagnosed patients who had concomitant esophageal adenocarcinoma.Conclusions: These global gene expression patterns, along with individual genes culled from them, represent potential biomarkers for the early diagnosis of esophageal adenocarcinoma from normal esophageal epithelia. Genes discovered in normal esophagus that are differentially expressed in patients with vs. without esophageal adenocarcinoma merit further pursuit in molecular genetic, functional, and therapeutic interventional studies.

Florin M. Selaru

2007-01-01

162

A Lin's method approach to finding and continuing heteroclinic connections involving periodic orbits  

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We present a numerical method for finding and continuing heteroclinic connections of vector fields that involve periodic orbits. Specifically, we concentrate on the case of a codimension-d heteroclinic connection from a saddle equilibrium to a saddle periodic orbit, denoted EtoP connection for short. By employing a Lin's method approach we construct a boundary value problem that has as its solution two orbit segments, one from the equilibrium to a suitable section ? and the other from ? to the periodic orbit. The difference between their two end points in ? can be chosen in a d-dimensional subspace, and this gives rise to d well-defined test functions that are called the Lin gaps. A connecting orbit can be found in a systematic way by closing the Lin gaps one by one in d consecutive continuation runs. Indeed, any common zero of the Lin gaps corresponds to an EtoP connection, which can then be continued in system parameters. The performance of our method is demonstrated with a number of examples. Specifically, we computate different types of EtoP orbits in the Lorenz system, in a vector-field model of a saddle-node Hopf bifurcation with global reinjection and in a four-dimensional Duffing-type system. Finally, we demonstrate the versatility of our geometric approach by finding a codimension-zero heteroclinic connection between two saddle periodic orbits in a four-dimensional vector field.

Krauskopf, Bernd; Rieß, Thorsten

2008-08-01

163

A simple method for finding explicit analytic transition densities of diffusion processes with general diploid selection.  

Science.gov (United States)

The transition density function of the Wright-Fisher diffusion describes the evolution of population-wide allele frequencies over time. This function has important practical applications in population genetics, but finding an explicit formula under a general diploid selection model has remained a difficult open problem. In this article, we develop a new computational method to tackle this classic problem. Specifically, our method explicitly finds the eigenvalues and eigenfunctions of the diffusion generator associated with the Wright-Fisher diffusion with recurrent mutation and arbitrary diploid selection, thus allowing one to obtain an accurate spectral representation of the transition density function. Simplicity is one of the appealing features of our approach. Although our derivation involves somewhat advanced mathematical concepts, the resulting algorithm is quite simple and efficient, only involving standard linear algebra. Furthermore, unlike previous approaches based on perturbation, which is applicable only when the population-scaled selection coefficient is small, our method is nonperturbative and is valid for a broad range of parameter values. As a by-product of our work, we obtain the rate of convergence to the stationary distribution under mutation-selection balance. PMID:22209899

Song, Yun S; Steinrücken, Matthias

2012-03-01

164

Fast simulators for satellite cloud optical centroid pressure retrievals; evaluation of OMI cloud retrievals  

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Full Text Available The cloud Optical Centroid Pressure (OCP is a satellite-derived parameter that is commonly used in trace-gas retrievals to account for the effects of clouds on near-infrared through ultraviolet radiance measurements. Fast simulators are desirable to further expand the use of cloud OCP retrievals into the operational and climate communities for applications such as data assimilation and evaluation of cloud vertical structure in general circulation models. In this paper, we develop and validate fast simulators that provide estimates of the cloud OCP given a vertical profile of optical extinction. We use a pressure-weighting scheme where the weights depend upon optical parameters of clouds and/or aerosols. A cloud weighting function is easily extracted using this formulation. We then use fast simulators to compare two different satellite cloud OCP retrievals, from the Ozone Monitoring Instrument (OMI, with estimates based on collocated cloud extinction profiles from a combination of CloudSat radar and MODIS visible radiance data. These comparisons are made over a wide range of conditions to provide a comprehensive validation of the OMI cloud OCP retrievals. We find generally good agreement between OMI cloud OCPs and those predicted by CloudSat. However, the OMI cloud OCPs from the two independent algorithms agree better with each other than either does with the estimates from CloudSat/MODIS. Differences between OMI cloud OCPs and those based on CloudSat/MODIS may result from undetected snow/ice at the surface, cloud 3-D effects, cases of low clouds obscurred by ground-clutter in CloudSat observations and by opaque high clouds in CALIPSO lidar observations, and the fact that CloudSat/CALIPSO only observes a relatively small fraction of an OMI field-of-view.

J. Joiner

2012-03-01

165

Fast Simulators for Satellite Cloud Optical Centroid Pressure Retrievals, 1. Evaluation of OMI Cloud Retrievals  

Science.gov (United States)

The cloud Optical Centroid Pressure (OCP), also known as the effective cloud pressure, is a satellite-derived parameter that is commonly used in trace-gas retrievals to account for the effects of clouds on near-infrared through ultraviolet radiance measurements. Fast simulators are desirable to further expand the use of cloud OCP retrievals into the operational and climate communities for applications such as data assimilation and evaluation of cloud vertical structure in general circulation models. In this paper, we develop and validate fast simulators that provide estimates of the cloud OCP given a vertical profile of optical extinction. We use a pressure-weighting scheme where the weights depend upon optical parameters of clouds and/or aerosol. A cloud weighting function is easily extracted using this formulation. We then use fast simulators to compare two different satellite cloud OCP retrievals from the Ozone Monitoring Instrument (OMI) with estimates based on collocated cloud extinction profiles from a combination of CloudS at radar and MODIS visible radiance data. These comparisons are made over a wide range of conditions to provide a comprehensive validation of the OMI cloud OCP retrievals. We find generally good agreement between OMI cloud OCPs and those predicted by CloudSat. However, the OMI cloud OCPs from the two independent algorithms agree better with each other than either does with the estimates from CloudSat/MODIS. Differences between OMI cloud OCPs and those based on CloudSat/MODIS may result from undetected snow/ice at the surface, cloud 3-D effects, low altitude clouds missed by CloudSat, and the fact that CloudSat only observes a relatively small fraction of an OMI field-of-view.

Joiner, J.; Vasilkov, A.; Gupta, P.; Bhartia, P. K.; Veefkind, P.; Sneep, M.; de Haan, J.; Polonsky, I.; Spurr, R.

2012-01-01

166

A Tabu Search Method for Finding Minimal Multi-Homogeneous Bézout Number  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Problem statement: A homotopy method has proven to be reliable for computing all of the isolated solutions of a multivariate polynomial system. The multi-homogeneous Bézout number of a polynomial system is the number of paths that one has to trace in order to compute all of its isolated solutions. Each partition of the variables corresponds to a multi-homogeneous Bézout number. It is a crucial problem to find a partition with the minimum multi-homogeneous Bézout number since the siz...

Bawazir, Hassan M. S.; Rahman, Ali A.

2010-01-01

167

Application of a Bayesian method to absorption spectral-line finding in simulated ASKAP data  

CERN Document Server

The large spectral bandwidth and wide field-of-view of the Australian SKA Pathfinder radio telescope will open up a completely new parameter space for large extragalactic HI surveys. Here we focus on identifying and parametrising HI absorption-lines which occur in the line of sight towards strong radio continuum sources. We have developed a method for simultaneously finding and fitting HI absorption-lines in radio data by using multi-nested sampling, a Bayesian Monte-arlo algorithm. The method is tested on a simulated ASKAP data cube, and is shown to be reliable at detecting absorption-lines in low signal-to-noise data without the need to smooth or alter the data. Estimation of the local Bayesian evidence statistic provides a quantitative criterion for assigning significance to a detection and selecting between competing analytical line-profile models.

Allison, J R; Whiting, M T

2011-01-01

168

Application of a Bayesian Method to Absorption Spectral-Line Finding in Simulated ASKAP Data  

Science.gov (United States)

The large spectral bandwidth and wide field of view of the Australian SKA Pathfinder radio telescope will open up a completely new parameter space for large extragalactic HI surveys. Here we focus on identifying and parametrising HI absorption lines which occur in the line of sight towards strong radio continuum sources. We have developed a method for simultaneously finding and fitting HI absorption lines in radio data by using multi-nested sampling, a Bayesian Monte Carlo algorithm. The method is tested on a simulated ASKAP data cube, and is shown to be reliable at detecting absorption lines in low signal-to-noise data without the need to smooth or alter the data. Estimation of the local Bayesian evidence statistic provides a quantitative criterion for assigning significance to a detection and selecting between competing analytical line-profile models.

Allison, J. R.; Sadler, E. M.; Whiting, M. T.

2012-10-01

169

A new method of finding all Roots of simple quaternionic polynomials  

CERN Document Server

In this paper, we provide a new method to find all zeros of polynomials with quaternionic coefficients located on only one side of the powers of the variable (these polynomials are called simple polynomials). This method is much more efficient and much simpler than the known one in [D. Janovska and G. Opfer, A note on the computation of all zeros of simple quaternionic polynomials, SIAM J. Numer. Anal., 48(1)(2010), pp. 244-256]. We recover several known results, and deduce several interesting consequences concerning solving equations with all real coefficients or complex coefficients which do not seem to be deduced easily from the results in [D. Janovska and G. Opfer, A note on the computation of all zeros of simple quaternionic polynomials, SIAM J. Numer. Anal., 48(1)(2010), pp. 244-256]. We also give a necessary and sufficient condition for a simple quaternionic polynomials to have finitely many solutions (only isolated solutions).

Feng, Lianggui

2011-01-01

170

Application of Artificial Intelligence methods in Finding Program Comprehension Differences in Novice Object Oriented Programmers  

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Full Text Available Program comprehension is the first step required for software maintenance, which accounts for a considerable number of job opportunities. For this to happen, it seems obvious that improving this ability in the teaching environment is required. The literature shows, however, that not enough solutions for improving program comprehension are offered as much as for programming itself.The aim of this research therefore, is to find a pattern of how different students vary in terms of comprehending a code written in an object-oriented language. For this, we have focused on two concepts including inheritance and polymorphism, gathered data online and analyzed it qualitatively. To find the right subject for all the students to study, a data mining technique i.e., the K-means clustering algorithm, was used.Results showed that a slight difference in programming experience can have a significant impact on program comprehension ability. The methods that were used by participants who succeeded in the experiment were the same as methods used by experts as mentioned in earlier research. Inheritance and polymorphism did not play an important role in lack of success in the process of program comprehension.

Marzieh Ahmadzadeh

2013-09-01

171

Microlensed image centroid motions by an exotic lens object with negative convergence or negative mass  

Science.gov (United States)

Gravitational lens models with negative convergence inspired by modified gravity theories, exotic matter, and energy have been recently examined in such a way that a static and spherically symmetric modified spacetime metric depends on the inverse distance to the nth power (n=1 for Schwarzschild metric, n=2 for Ellis wormhole, and n?1 for an extended spherical distribution of matter such as an isothermal sphere) in the weak-field approximation. Some of the models act as if a convex lens, whereas the others are repulsive on light rays like a concave lens. The present paper considers microlensed image centroid motions by the exotic lens models. Numerical calculations show that, for large n cases in the convex-type models, the centroid shift from the source position might move on a multiply connected curve like a bow tie, while it is known to move on an ellipse for the n=1 case and to move on an oval curve for n=2. The distinctive feature of the microlensed image centroid may be used for searching (or constraining) localized exotic matter or energy with astrometric observations. It is shown also that the centroid shift trajectory for concave-type repulsive models might be elongated vertically to the source motion direction like a prolate spheroid, whereas that for convex-type models such as the Schwarzschild one is tangentially elongated like an oblate spheroid.

Kitamura, Takao; Izumi, Koji; Nakajima, Koki; Hagiwara, Chisaki; Asada, Hideki

2014-04-01

172

Data Fusion for Identity Estimation and Tracking of Centroid using Imaging Sensor Data  

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Full Text Available Two aspects involved in automatic target recognition namely, (i Location and identity estimation (LIE of a target by fusing infrared (IR and acoustic sensor data, and (ii centroid tracking for target state estimation using IR sensor data are discussed in this paper. The LIE has been achieved using a combination of Bayesian fusion and one of the three search algorithms namely, metropolis hastings (MH, simulated annealing (SA and gradual greedy (GG. It was observed that the performance of the GG search algorithms was better in terms of success rate which has been evaluated through Monte Carlo simulations. For tracking of the centroid, an algorithm, where the centroid of the gray level image is tracked using probabilistic data association filter, has been implemented. Simulated data results indicate good tracking performance of this algorithm. For robust tracking of centroid, the track from the imaging sensor was fused with the track from ground-based radar using state vector fusion. It was observed that fusion generates robust tracks even when there is data loss in one of the sensors.

V.P.S. Naidu

2007-09-01

173

Sum rules for isospin centroids in pick-up reactions on general multishell target states  

CERN Document Server

Sum Rules equations for pick-up reactions are presented for the first time for the energy centroids of states both for the isospin T_, which, at the present moment, are difficult to handle analytically. These terms are managed by combining these equations with the known stripping reactions equations. Sample applications of these equations to experimental data are presented.

Bansal, R K; Kumar, A; Kumar, Ashwani

1996-01-01

174

A pilot study quantifying the shape of tidal breathing waveforms using centroids in health and COPD.  

Science.gov (United States)

During resting tidal breathing the shape of the expiratory airflow waveform differs with age and respiratory disease. While most studies quantifying these changes report time or volume specific metrics, few have concentrated on waveform shape or area parameters. The aim of this study was to derive and compare the centroid co-ordinates (the geometric centre) of inspiratory and expiratory flow-time and flow-volume waveforms collected from participants with or without COPD. The study does not aim to test the diagnostic potential of these metrics as an age matched control group would be required. Twenty-four participants with COPD and thirteen healthy participants who underwent spirometry had their resting tidal breathing recorded. The flow-time data was analysed using a Monte Carlo simulation to derive the inspiratory and expiratory flow-time and flow-volume centroid for each breath. A comparison of airflow waveforms show that in COPD, the breathing rate is faster (17 ± 4 vs 14 ± 3 min(-1)) and the time to reach peak expiratory flow shorter (0.6 ± 0.2 and 1.0 ± 0.4 s). The expiratory flow-time and flow-volume centroid is left-shifted with the increasing asymmetry of the expired airflow pattern induced by airway obstruction. This study shows that the degree of skew in expiratory airflow waveforms can be quantified using centroids. PMID:23881418

Williams, E M; Powell, T; Eriksen, M; Neill, P; Colasanti, R

2014-02-01

175

The optical system for JASMINE and the CCD centroiding experiment  

Science.gov (United States)

We have investigated the optical design for the Japan astrometry satellite mission (JASMINE). In order to accomplish measurements of astrometric parameters with high accuracy, optics with a long focal length and a wide focal plane for astrometry are required. In 1977 Korsch proposed a three mirror system with a long focal length and a wide focal plane. The Korsch system is one of the convincing models. However, the center of the field is totally vignetted because of the fold mirror. Therefore we consider an improved Korsch system in which the center of the field is not vignetted. Finally, we obtain the diffraction limited optical design with small distortion. Our project needs a common astrometric technique to obtain precise positions of star images on solid state detectors to accomplish its objectives. In order to determine the centers of stars, an image of the point source must be focused onto the CCD array with a spread of a few pixels. The distribution of photons (photoelectrons) over a set of pixels enables us to estimate positions of stars with sub-pixel accuracy. We modify the algorithm to estimate the real positions of stars from the photon weighted mean, which was originally developed by the FAME (Full-Sky Astrometric Mapping Explorer) group. Finally, we obtain the results from the experiment that the accuracy of estimation of distance between two stars has a variance of about 1/300 pixel; that is, the error for one measurement is about 1/300 pixel, which is almost an ideal result given by Poisson photon noise. We also investigate the accuracy of estimation of positions with a different size of PSF. In this case also, we find that the accuracy of estimation has a variance of about 1/300 pixel.

Yano, Taihei; Gouda, Naoteru; Kobayashi, Yukiyasu; Tsujimoto, Takuji; Nakajima, Tadashi; Hanada, Hideo; Yamada, Yoshiyuki; Araki, Hiroshi; Tazawa, Seiichi; Asari, Kazuyoshi; Tsuruta, Seiitsu; Kawano, Nobuyuki; Takato, Naruhisa

2005-04-01

176

Meta-Analysis of Methods and Findings of Urban Quality of Life in Iran  

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Full Text Available IntroductionThere is no agreement on what city and urban lifestyle are. It is not just about minimum factors that each city must have, but also about social interactions, social needs and individual perceptions which are dependent on cultural characteristics and geographical details. Generally speaking, cities have complex systems of transportation, sanitation, utilities, land usage, social connections and economic actions. These systems are always in the process of changing and developing. So, development of cities leads to new lifestyles and create what we may call urban life. Development of urban life causes concentration of equipments and resources in cities. Also, it is clear that a mere focus on quantitative facts of urban development is not enough to get to the efficient way of life. Hence researchers and managers have decided to pay more attention to factors which are more related to quality of urban life. In other words, after an initial attention to quantitative development of cities, the concept of quality of life is now getting attention in terms of qualitative factors. Due to this shift, a great deal of scientific and practical studies have been conducted and many new things have been revealed. Medical, sociological, psychological, environmental and economic points of views led to create new indexes and multidimensional frameworks. More than that, each city arrives at special findings which are linked to its local specifications. Because of diversity of results in different cases and cities, reaching to a shared and unique conclusion for urban quality of life is not easy. So the purpose of this study is to centralize and summarize the results of various studies on this topic in Iran. Meta-analysis is a research method for arriving at a specific knowledge from different studies. This research method was introduced in the late 1970s and soon became famous because of its abilities to get clear conclusions. Material & MethodsThis paper has analyzed Iranian scientific studies on quality of life, which were published until 2012. Meta-analysis is a tool for integrating scattered results and achieving to a new understanding in order to develop boundaries of knowledge. Identifying patterns among study results, contrasting and combining different studies, identifying a common measure of size effects, overcoming bias and doing systematic reviews are different benefits and applications of this method. Some steps are taken in order to get a reliable meta-analysis. First of all, it was decided to find keywords which are related to urban quality of life. Based on ideas of experts and those keywords, all Persian scientific databases which could have articles related to quality of urban life were searched. Initially, 45 articles were included in the sample. Later on, however, some of these articles which were not scientifically acceptable or belonged to medical fields were excluded. After this process, 27 articles were selected, of which 17 articles are published in scientific peer-reviewed journals and the remaining 10 article in other journals. Based on these categories, it was decided to separate results into two different types: "results of studies published in peer-reviewed journals" and "result of studies published in non-peer-reviewed journals". After that, specific findings of articles were written and summarized. For doing this, 9 important dimensions were chosen which were used for filtering the articles. Table 1 provides a view of these indicators. Table 1- View of Filtering IndicatorsDimensionsIndicatorsResearch methodtype of research, data collection method,Sampling methodSamples, specified samples, quality of samplesResearch frameworkAssumptions and Questions and framework selectingValidity and reliabilityThe amount of validity and reliability and declaration of itTheoretical ApproachThe main approach to quality of urban life and clarity of expressionSubjective and objective indicatorsType of indicators (objective and subjective and their separation in final resultsMain dimensionsEnvironment

Gholamreza Kazemian

2013-01-01

177

4D tumor centroid tracking using orthogonal 2D dynamic MRI: Implications for radiotherapy planning  

Energy Technology Data Exchange (ETDEWEB)

Purpose: Current pretreatment, 4D imaging techniques are suboptimal in that they sample breathing motion over a very limited “snapshot” in time. Heretofore, long-duration, 4D motion characterization for radiotherapy planning, margin optimization, and validation have been impractical for safety reasons, requiring invasive markers imaged under x-ray fluoroscopy. To characterize 3D tumor motion and associated variability over durations more consistent with treatments, the authors have developed a practical dynamic MRI (dMRI) technique employing two orthogonal planes acquired in a continuous, interleaved fashion.Methods: 2D balanced steady-state free precession MRI was acquired continuously over 9–14 min at approximately 4 Hz in three healthy volunteers using a commercial 1.5 T system; alternating orthogonal imaging planes (sagittal, coronal, sagittal, etc.) were employed. The 2D in-plane pixel resolution was 2 × 2 mm{sup 2} with a 5 mm slice profile. Simultaneous with image acquisition, the authors monitored a 1D surrogate respiratory signal using a device available with the MRI system. 2D template matching-based anatomic feature registration, or tracking, was performed independently in each orientation. 4D feature tracking at the raw frame rate was derived using spline interpolation.Results: Tracking vascular features in the lung for two volunteers and pancreatic features in one volunteer, the authors have successfully demonstrated this method. Registration error, defined here as the difference between the sagittal and coronal tracking result in the SI direction, ranged from 0.7 to 1.6 mm (1?) which was less than the acquired image resolution. Although the healthy volunteers were instructed to relax and breathe normally, significantly variable respiration was observed. To demonstrate potential applications of this technique, the authors subsequently explored the intrafraction stability of hypothetical tumoral internal target volumes and 3D spatial probability distribution functions. The surrogate respiratory information allowed the authors to show how this technique can be used to study correlations between internal and external (surrogate) information over these prolonged durations. However, compared against the gold standard of the time stamps in the dMRI frames, the temporal synchronization of the surrogate 1D respiratory information was shown to be likely unreliable.Conclusions: The authors have established viability of a novel and practical pretreatment, 4D tumor centroid tracking method employing a commercially available dynamic MRI sequence. Further developments from the vendor are likely needed to provide a reliably synchronized surrogate 1D respiratory signal, which will likely broaden the utility of this method in the pretreatment radiotherapy planning context.

Tryggestad, Erik [Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231 and Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota 55905 (United States); Flammang, Aaron; Shea, Steven M. [Center for Applied Medical Imaging, Siemens Corporation, Corporate Technology, Baltimore, Maryland 21205 (United States); Hales, Russell; Herman, Joseph; Lee, Junghoon; McNutt, Todd; Roland, Teboh; Wong, John [Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231 (United States)

2013-09-15

178

4D tumor centroid tracking using orthogonal 2D dynamic MRI: Implications for radiotherapy planning  

International Nuclear Information System (INIS)

Purpose: Current pretreatment, 4D imaging techniques are suboptimal in that they sample breathing motion over a very limited “snapshot” in time. Heretofore, long-duration, 4D motion characterization for radiotherapy planning, margin optimization, and validation have been impractical for safety reasons, requiring invasive markers imaged under x-ray fluoroscopy. To characterize 3D tumor motion and associated variability over durations more consistent with treatments, the authors have developed a practical dynamic MRI (dMRI) technique employing two orthogonal planes acquired in a continuous, interleaved fashion.Methods: 2D balanced steady-state free precession MRI was acquired continuously over 9–14 min at approximately 4 Hz in three healthy volunteers using a commercial 1.5 T system; alternating orthogonal imaging planes (sagittal, coronal, sagittal, etc.) were employed. The 2D in-plane pixel resolution was 2 × 2 mm2 with a 5 mm slice profile. Simultaneous with image acquisition, the authors monitored a 1D surrogate respiratory signal using a device available with the MRI system. 2D template matching-based anatomic feature registration, or tracking, was performed independently in each orientation. 4D feature tracking at the raw frame rate was derived using spline interpolation.Results: Tracking vascular features in the lung for two volunteers and pancreatic features in one volunteer, the authors have successfully demonstrated this method. Registration error, defined here as the difference between the sagittal and coronal tracking result in the SI direction, ranged from 0.7 to 1.6 mm (1?) which was less than the acquired image resolution. Although the healthy volunteers were instructed to relax and breathe normally, significantly variable respiration was observed. To demonstrate potential applications of this technique, the authors subsequently explored the intrafraction stability of hypothetical tumoral internal target volumes and 3D spatial probability distribution functions. The surrogate respiratory information allowed the authors to show how this technique can be used to study correlations between internal and external (surrogate) information over these prolonged durations. However, compared against the gold standard of the time stamps in the dMRI frames, the temporal synchronization of the surrogate 1D respiratory information was shown to be likely unreliable.Conclusions: The authors have established viability of a novel and practical pretreatment, 4D tumor centroid tracking method employing a commercially available dynamic MRI sequence. Further developments from the vendor are likely needed to provide a reliably synchronized surrogate 1D respiratory signal, which will likely broaden the utility of this method in the pretreatment radiotherapy planning context

179

Old Wine in New Skins: The Sensitivity of Established Findings to New Methods  

Science.gov (United States)

Findings from an evaluation of a model system for delivering mental health services to youth were reassessed to determine the robustness of key findings to the use of methodologies unavailable to the original analysts. These analyses address a key concern about earlier findings--that the quasi-experimental design involved the comparison of two…

Foster, E. Michael; Wiley-Exley, Elizabeth; Bickman, Leonard

2009-01-01

180

CentroidAlign-Web: A Fast and Accurate Multiple Aligner for Long Non-Coding RNAs  

Directory of Open Access Journals (Sweden)

Full Text Available Due to the recent discovery of non-coding RNAs (ncRNAs, multiple sequence alignment (MSA of those long RNA sequences is becoming increasingly important for classifying and determining the functional motifs in RNAs. However, not only primary (nucleotide sequences, but also secondary structures of ncRNAs are closely related to their function and are conserved evolutionarily. Hence, information about secondary structures should be considered in the sequence alignment of ncRNAs. Yet, in general, a huge computational time is required in order to compute MSAs, taking secondary structure information into account. In this paper, we describe a fast and accurate web server, called CentroidAlign-Web, which can handle long RNA sequences. The web server also appropriately incorporates information about known secondary structures into MSAs. Computational experiments indicate that our web server is fast and accurate enough to handle long RNA sequences. CentroidAlign-Web is freely available from http://centroidalign.ncrna.org/.

Michiaki Hamada

2013-03-01

 
 
 
 
181

1997-2008: 11 years of European-Mediterranean Regional Centroid Moment Tensors and their dissemination  

Science.gov (United States)

The European-Mediterranean Regional Centroid Moment Tensor (RCMT) Catalog collects seismic moment tensor solutions that have been routinely computed since 1997 for earthquakes with moderate magnitude (4.5 exported in various formats, or mapped directly on the web page (beach balls). Two important flags were introduced, allowing us to include in the database new events still in the preliminary stages of analysis or in need of further refinements. The first flag distinguishes Definitive and Quick solutions, while the second one categorizes events in 4 Quality levels on the basis of changes of centroid coordinates or when the depth needs to be fixed or when the double couple component is too big (Pondrelli et al., PEPI, 2006).

Pondrelli, S.; Morelli, A.; Ekström, G.; Postpischl, L.; Salimbeni, S.

2008-12-01

182

Artificial neural networks for centroiding elongated spots in Shack-Hartmann wavefront sensors  

Science.gov (United States)

The use of adaptive optics in extremely large telescopes brings new challenges, one of which is the treatment of images from Shack-Hartmann wavefront sensors. When using this type of sensor in conjunction with laser guide stars to sample the pupils of telescopes with diameters of more than 30 m, it is necessary to compute the centroid of elongated spots, whose elongation angle and aspect ratio are changing across the telescope pupil. Existing techniques, such as the matched filter technique, have been considered as the best ways to compute the centroid of elongated spots, but these are not good at coping with the effect of a variation in the sodium profile. In this paper, we propose a new technique using artificial neural networks. This technique takes advantage of the neural network's ability to cope with changing conditions, and it outperforms existing techniques in this context. We have developed comprehensive simulations to explore this technique and we compare it with existing algorithms.

Mello, A. T.; Kanaan, A.; Guzman, D.; Guesalaga, A.

2014-05-01

183

Optimization of Phenolic Antioxidant Extraction from Wuweizi (Schisandra chinensis) Pulp Using Random-Centroid Optimazation Methodology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The extraction optimization and composition analysis of polyphenols in the fresh pulp of Wuweizi (Schisandra chinensis) have been investigated in this study. The extraction process of polyphenols from Wuweizi pulp was optimized using Random-Centroid Optimization (RCO) methodology. Six factors including liquid and solid ratio, ethanol concentration, pH, temperature, heating time and extraction times, and three extraction targets of polyphenol content, antioxidant activity and extract yield wer...

Xiong (Bill) Yu; Hao Jing; Xia Wu

2011-01-01

184

Transition state-finding strategies for use with the growing string method.  

Science.gov (United States)

Efficient identification of transition states is important for understanding reaction mechanisms. Most transition state search algorithms require long computational times and a good estimate of the transition state structure in order to converge, particularly for complex reaction systems. The growing string method (GSM) [B. Peters et al., J. Chem. Phys. 120, 7877 (2004)] does not require an initial guess of the transition state; however, the calculation is still computationally intensive due to repeated calls to the quantum mechanics code. Recent modifications to the GSM [A. Goodrow et al., J. Chem. Phys. 129, 174109 (2008)] have reduced the total computational time for converging to a transition state by a factor of 2 to 3. In this work, three transition state-finding strategies have been developed to complement the speedup of the modified-GSM: (1) a hybrid strategy, (2) an energy-weighted strategy, and (3) a substring strategy. The hybrid strategy initiates the string calculation at a low level of theory (HF/STO-3G), which is then refined at a higher level of theory (B3LYP/6-31G(*)). The energy-weighted strategy spaces points along the reaction pathway based on the energy at those points, leading to a higher density of points where the energy is highest and finer resolution of the transition state. The substring strategy is similar to the hybrid strategy, but only a portion of the low-level string is refined using a higher level of theory. These three strategies have been used with the modified-GSM and are compared in three reactions: alanine dipeptide isomerization, H-abstraction in methanol oxidation on VO(x)/SiO(2) catalysts, and C-H bond activation in the oxidative carbonylation of toluene to p-toluic acid on Rh(CO)(2)(TFA)(3) catalysts. In each of these examples, the substring strategy was proved most effective by obtaining a better estimate of the transition state structure and reducing the total computational time by a factor of 2 to 3 compared to the modified-GSM. The applicability of the substring strategy has been extended to three additional examples: cyclopropane rearrangement to propylene, isomerization of methylcyclopropane to four different stereoisomers, and the bimolecular Diels-Alder condensation of 1,3-butadiene and ethylene to cyclohexene. Thus, the substring strategy used in combination with the modified-GSM has been demonstrated to be an efficient transition state-finding strategy for a wide range of types of reactions. PMID:19566143

Goodrow, Anthony; Bell, Alexis T; Head-Gordon, Martin

2009-06-28

185

Determination of the centroid of interaction of crystals in block detectors for PET  

International Nuclear Information System (INIS)

Cut blocks of bismuth germanate (BGO) are the most common detectors used in current positron emission tomography (PET) imaging systems. The distribution of light received by four photo-multiplier (PMT) cathodes is used to assign each gamma ray to one crystal. Most 511-keV gamma rays undergo Compton scattering in the crystal before being photoelectrically absorbed. This, and the effects of dense metal septa between blocks change the response of the crystals depending on their position in the block and the angle of incidence of gamma rays on the block. For each projection, the authors used Monte Carlo simulation to determine the ''centroid of interaction'' for each crystal in the block. The authors found the crystals appear to be packed slightly closer in each block than their geometrical distance. The authors found the location of the crystal's centroid relative to its center changes along each projection. The authors simulated the 4 x 4 crystal arrays of the Scanditronix PC2048-B, determined the centroid of interaction for each crystal, then modified the reconstruction program's interpolation parameters. The spatial resolution improved by up to 10%, and a distortion of 1.5 mm at the edge of the imaging field was eliminated

186

Enhancing spatial resolution of soft x-ray CCD detectors by single-photon centroid determination  

CERN Document Server

In Charge Coupled Device (CCD) detectors the electrons excited upon absorption of a single x-ray photon quickly diffuse and generate charge-spots often larger than pixel dimensions. In the soft x-ray range this phenomenon drastically limits the effective spatial resolution to approximately 25\\mu m, irrespective of the pixel size. For very low fluence the charge-cloud centroid determination can be used, on each individual spot, to estimate the actual photon impact position with sub-pixel precision. The readout noise and speed, together with the charge and spatial undersampling, are the main factors limiting the accuracy of this procedure in commercial devices. We have developed and extensively tested an algorithm for efficient centroid reconstruction on images acquired by low noise detectors not designed for single photon counting. We have thus measured a position uncertainty of 6-7\\mu m in CCDs with 13.5\\mu m and 20.0\\mu m pixel size, around 1 keV photon energy. We have analyzed the centroid calculation perfo...

Amorese, Andrea; Braicovich, Lucio; Ghiringhelli, Giacomo

2014-01-01

187

Centroid and Envelope Dynamics of High-Intensity Charged-Particle Beams in an External Focusing Lattice and Oscillating Wobbler  

International Nuclear Information System (INIS)

The centroid and envelope dynamics of a high-intensity charged-particle beam are investigated as a beam smoothing technique to achieve uniform illumination over a suitably chosen region of the target for applications to ion-beam-driven high energy density physics and heavy ion fusion. The motion of the beam centroid projected onto the target follows a smooth pattern to achieve the desired illumination, for improved stability properties during the beam-target interaction. The centroid dynamics is controlled by an oscillating 'wobbler', a set of electrically biased plates driven by rf voltage.

188

Centroid and Envelope Dynamics of High-intensity Charged Particle Beams in an External Focusing Lattice and Oscillating Wobbler  

International Nuclear Information System (INIS)

The centroid and envelope dynamics of a high-intensity charged particle beam are investigated as a beam smoothing technique to achieve uniform illumination over a suitably chosen region of the target for applications to ion-beam-driven high energy density physics and heavy ion fusion. The motion of the beam centroid projected onto the target follows a smooth pattern to achieve the desired illumination, for improved stability properties during the beam-target interaction. The centroid dynamics is controlled by an oscillating 'wobbler', a set of electrically-biased plates driven by RF voltage.

189

Centroid and Envelope Dynamics of High-intensity Charged Particle Beams in an External Focusing Lattice and Oscillating Wobbler  

Energy Technology Data Exchange (ETDEWEB)

The centroid and envelope dynamics of a high-intensity charged particle beam are investigated as a beam smoothing technique to achieve uniform illumination over a suitably chosen region of the target for applications to ion-beam-driven high energy density physics and heavy ion fusion. The motion of the beam centroid projected onto the target follows a smooth pattern to achieve the desired illumination, for improved stability properties during the beam-target interaction. The centroid dynamics is controlled by an oscillating "wobbler", a set of electrically-biased plates driven by RF voltage. __________________________________________________

Hong Qin, Ronald C. Davidson and B. Grant Logan

2010-04-28

190

Centroid and Envelope Dynamics of High-Intensity Charged-Particle Beams in an External Focusing Lattice and Oscillating Wobbler  

Science.gov (United States)

The centroid and envelope dynamics of a high-intensity charged-particle beam are investigated as a beam smoothing technique to achieve uniform illumination over a suitably chosen region of the target for applications to ion-beam-driven high energy density physics and heavy ion fusion. The motion of the beam centroid projected onto the target follows a smooth pattern to achieve the desired illumination, for improved stability properties during the beam-target interaction. The centroid dynamics is controlled by an oscillating “wobbler,” a set of electrically biased plates driven by rf voltage.

Qin, Hong; Davidson, Ronald C.; Logan, B. Grant

2010-06-01

191

Infant feeding experiences among teen mothers in North Carolina: Findings from a mixed-methods study  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Adolescent mothers in the U.S. are much less likely to initiate breastfeeding than older mothers, and teens who do initiate breastfeeding tend to breastfeed for shorter durations. The purpose of this mixed-methods study is to investigate breastfeeding practices, barriers and facilitators among adolescent mothers ages 17 and younger. Methods Quantitative descriptive analyses are conducted using data from the North Carolina Pregnancy Risk Assessment Monitoring System (PRAMS. The population-based sample comprises 389 teens ages 13-17 giving birth to a live born infant in North Carolina in 2000 - 2005 and in 2007. Qualitative analyses are based on in-depth interviews with 22 Black, White and Hispanic teen mothers residing in rural and urban areas of North Carolina conducted between November 2007 and February 2009. Results In quantitative analyses, 52% (196 of 389 of North Carolina teen mothers initiated breastfeeding, but half of those who initiated breastfeeding (92/196 stopped within the first month postpartum. Hispanic teens (44/52 or 89% were much more likely than Black (61/159 or 41% or White teens (87/164 or 52% to initiate breastfeeding and to continue for a longer duration. Nearly sixty two percent (29/52 of Hispanic respondents breastfed for greater than four weeks as compared to 16% (29/159 of Black respondents and 26% (39/164 of White respondents. Common barriers to breastfeeding initiation and continuation included not liking breastfeeding, returning to school, nipple pain, and insufficient milk. Qualitative data provided context for the quantitative findings, elucidating the barriers and facilitators to breastfeeding from the teens' perspective and insight into the ways in which breastfeeding support to teens could be enhanced. Conclusions The large number of adolescents ceasing breastfeeding within the first month points to the need for more individualized follow-up after hospital discharge in the first few days postpartum, to address common technical challenges and to provide assistance managing the transition back to school. Provision of an extra home visit or outpatient visit for teens within the first few days following hospital discharge, and advocacy to make schools more compatible with breastfeeding, could potentially help teens who desire to breastfeed to successfully continue. These interventions warrant further research to test their effectiveness among adolescents.

Samandari Ghazaleh

2011-09-01

192

Southern Ocean jets and how to find them: Improving and comparing common jet detection methods  

Science.gov (United States)

study undertakes a detailed comparison of different methods used for detecting and tracking oceanic jets in the Southern Ocean. The methods under consideration are the gradient thresholding method, the probability density function (PDF) method, and the contour method. Some weaknesses of the gradient thresholding method are discussed and an enhancement (the WHOSE method), based on techniques from signal processing, is proposed. The WHOSE method is then compared to the other three methods. Quantitative comparison is undertaken using synthetic sea-surface height fields. The WHOSE method and the contour method are found to perform well even in the presence of a strong eddy field. In contrast, the standard gradient thresholding and PDF methods only perform well in high signal-to-noise ratio situations. The WHOSE, PDF, and the contour methods are then applied to data from the eddy-resolving Ocean General Circulation Model for the Earth Simulator. While the three methods are in broad agreement on the location of the main ACC jets, the nature of the jet fields they produce differ. In particular, the WHOSE method reveals a fine-scale jet field with complex braiding behavior. It is argued that this fine-scale jet field may affect the calculation of eddy diffusivities. Finally, recommendations based on this study are made. The WHOSE and gradient thresholding methods are more suitable for the study of jets as localized strong currents, useful for studies of tracer fluxes. The contour and PDF methods are recommended for studies linking jets to hydrographic fronts.

Chapman, Christopher C.

2014-07-01

193

Heap Base Coordinator Finding with Fault Tolerant Method in Distributed Systems  

Directory of Open Access Journals (Sweden)

Full Text Available Coordinator finding in wireless networks is a very important problem, and this problem is solved by suitable algorithms. The main goals of coordinator finding are synchronizing the processes at optimal using of the resources. Many different algorithms have been presented for coordinator finding. The most important leader election algorithms are the Bully and Ring algorithms. In this paper we analyze and compare these algorithms with together and we propose new approach with fault tolerant mechanisms base on heap for coordinator finding in wireless environment. Our algorithm's running time and message complexity compare favorably with existing algorithms. Our work involves substantial modifications of an existing algorithm and its proof, and we adapt the existing algorithms to the noisy environment base on fault tolerant mechanisms

Mehdi EffatParvar

2011-07-01

194

New Method for Finding a Series of Exact Solutions to Generalized Breaking Soliton Equation  

International Nuclear Information System (INIS)

In this paper, a new generalized extended tanh-function method is presented for constructing soliton-like, period-form solutions of nonlinear evolution equations (NEEs). This method is more powerful than the extended tanh-function method [Phys. Lett. A 277 (2000) 212] and the modified extended tanh-function method [Phys. Lett. A 285 (2001) 355]. Abundant new families of the exact solutions of Bogoyavlenskii's generalized breaking soliton equation are obtained by using this method and symbolic computation system Maple.

195

Enhanced multiposition method to suppress the north finding error caused by bias drift with fiber optic gyroscopes.  

Science.gov (United States)

We present an enhanced multiposition method (EMM) to suppress the north finding error caused by bias drift with fiber optic gyroscopes (FOGs). The new proposal is a static method to find the true north, and it employs a differential strategy and a rotation scheme of increasing step angle. Using the noise model of Allan variance, we analyze the north finding errors caused by angle random walk (ARW), rate random walk (RRW), and rate ramp (RR) theoretically, where RRW and RR are two main noise sources of bias drift, and ARW is the rate white noise. Theoretical analysis indicates that, in the traditional multiposition method (TMM), as the position number increases, the error caused by ARW decreases while that by bias drift increases. Therefore, the suppressions of ARW and bias drift are conflicted with each other. The north finding accuracy is limited by bias drift. In contrast, in EMM, both errors caused by ARW and bias drift will decrease as the position number increases. Experimental results with two specific FOGs verify our theoretical analysis. In our experiments, we study the effect of position number and step angle on the north finding accuracy. Utilizing the proposed EMM, for FOG-1, the north finding error has been reduced by 76.60%, and for FOG-2, a 36.33% reduction has been achieved. Our proposal provides a more effective and stable way to find true north, and it can also be applied to other rate gyroscopes. PMID:23872780

He, Changhong; Yang, Chuanchuan; Wang, Xinyue; Wang, Ziyu

2013-07-20

196

A method for finding the periodic solution of autonomous ordinary differential equations  

International Nuclear Information System (INIS)

Using the least square method, the problem for computing periodic solution of autonomous ordinary differential equations has been reduced to a problem of minimization on a normal plane. The conjugate gradient method is used to yield successive initial value, and the Runge-Kutta method is used to solve the initial value problem in the ordinary differential equations. So a new method for this problem is formed. As examples, it is applied to the Brusselator model and Field-Noyes model of Belousov-Zhabotinskii reactions. The numerical results obtained show that this method is very efficient. (author). 7 refs, 2 figs, 3 tabs

197

Finding ultracool brown dwarfs with MegaCam on CFHT: method and first results  

Science.gov (United States)

Aims: We present the first results of a wide field survey for cool brown dwarfs with the MegaCam camera on the CFHT telescope, the Canada-France Brown Dwarf Survey, hereafter CFBDS. Our objectives are to find ultracool brown dwarfs and to constrain the field-brown dwarf mass function thanks to a larger sample of L and T dwarfs. Methods: We identify candidates in CFHT/MegaCam i' and z' images using optimised psf-fitting within Source Extractor, and follow them up with pointed near-infrared imaging on several telescopes. Results: We have so far analysed over 350 square degrees and found 770 brown dwarf candidates brighter than z'_AB=22.5. We currently have J-band photometry for 220 of these candidates, which confirms 37% as potential L or T dwarfs. Some are among the reddest and farthest brown dwarfs currently known, including an independent identification of the recently published ULAS J003402.77-005206.7 and the discovery of a second brown dwarf later than T8, CFBDS J005910.83-011401.3. Infrared spectra of three T dwarf candidates confirm their nature, and validate the selection process. Conclusions: The completed survey will discover ~100 T dwarfs and ~500 L dwarfs or M dwarfs later than M8, approximately doubling the number of currently known brown dwarfs. The resulting sample will have a very well-defined selection function, and will therefore produce a very clean luminosity function. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. Based on observations made with the ESO New Technology Telescope at the La Silla Observatory under programme ID 76.C-0540(A), 77.C-0594, 77.A-0707, 78.A-0651, 78.C-0629 and 79.A-0663. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil) and CONICET (Argentina). Based on observations with the Kitt Peak National Observatory, National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under cooperative agreement with the National Science Foundation. Based on observations made with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. This paper includes data taken at The McDonald Observatory of The University of Texas at Austin.

Delorme, P.; Willott, C. J.; Forveille, T.; Delfosse, X.; Reylé, C.; Bertin, E.; Albert, L.; Artigau, E.; Robin, A. C.; Allard, F.; Doyon, R.; Hill, G. J.

2008-06-01

198

Study of Functional Variable Method for Finding Exact Solutions of Nonlinear Evolution Equations  

Directory of Open Access Journals (Sweden)

Full Text Available A direct method, called the functional variable method, has been used to construct the exact solutions of nonlinear evolution equations (NLEEs in mathematical physics. To illustrate the validity and advantages of this method, the (2+1 dimensional Boussinesq-Kadomtsev-Petviashvili (BKP equations and the new coupled Konno-Oono (KO equations are considered. The obtained solutions contain an explicit function of the variables in the considered equations. It has been shown that the method provides a powerful mathematical tool for solving NLEEs in mathematical physics and engineering fields without the help of computer algebra system.

Kamruzzaman KHAN

2015-03-01

199

Measurement of large displacements of the toroidal current centroid using an external coil diagnostic  

International Nuclear Information System (INIS)

Several sinusoidal and saddle coils have been used to measure the toroidal current centroid of discharges produced in a pulsed tokamak experiment. Careful analysis of the external coil measurements and elaborate calibrations made the measurements possible even for large displacements of the plasma current and the noncircular geometry of the diagnostic coils. The calibration techniques and the data analysis formula are described, and examples of the use of the external coils to measure m = 1 kinks of unstable toroidal Z-pinch discharges are presented

200

Vertex-centroid finite volume scheme on tetrahedral grids for conservation laws  

CERN Document Server

Vertex-centroid schemes are cell-centered finite volume schemes for conservation laws which make use of vertex values to construct high resolution schemes. The vertex values must be obtained through a consistent averaging (interpolation) procedure. A modified interpolation scheme is proposed which is better than existing schemes in giving positive weights in the interpolation formula. A simplified reconstruction scheme is also proposed which is also more accurate and efficient. For scalar conservation laws, we develop limited versions of the schemes which are stable in maximum norm by constructing suitable limiters. The schemes are applied to compressible flows governed by the Euler equations of inviscid gas dynamics.

Chandrashekar, Praveen

2011-01-01

 
 
 
 
201

Towards understanding household-level forest reliance in Cambodia - study sites, methods, and preliminary findings  

DEFF Research Database (Denmark)

There is growing international interest in the role of forests in poverty prevention and reduction. In consequence, this broad area of investigation has been subject to increased research; one major international research project is that facilitated by the Poverty Environment Network (PEN). This project covers a large number of sites in 26 countries throughout the tropics. The present report contains contextual details, methodological information and preliminary findings for the PEN sites in Cambodia.

Ra, Koy; Pichdara, Lonn

2011-01-01

202

An MLE method for finding LKB NTCP model parameters using Monte Carlo uncertainty estimates  

Science.gov (United States)

The aims of this work were to establish a program to fit NTCP models to clinical data with multiple toxicity endpoints, to test the method using a realistic test dataset, to compare three methods for estimating confidence intervals for the fitted parameters and to characterise the speed and performance of the program.

Carolan, Martin; Oborn, Brad; Foo, Kerwyn; Haworth, Annette; Gulliford, Sarah; Ebert, Martin

2014-03-01

203

Finding the Right Mix: Teaching Methods as Predictors for Student Progress on Learning Objectives  

Science.gov (United States)

This study extends existing student ratings research by exploring how teaching methods, individually and collectively, influence a minimum standard of student achievement on learning objectives and how class size impacts this influence. Twenty teaching methods were used to predict substantial or exceptional progress on each of 12 learning…

Glover, Jacob I.

2012-01-01

204

A method for finding solutions of the Hermitian theory of relativity which depend on three coordinates  

International Nuclear Information System (INIS)

A method is presented, which can generate solutions of the Hermitian theory of relativity from known solutions of the general theory of relativity, when the latter depend on three coordinates and are invariant under reversal of the fourth one. (author)

205

Paediatric cardiac CT examinations: impact of the iterative reconstruction method ASIR on image quality - preliminary findings  

International Nuclear Information System (INIS)

filtered back-projection method. Reconstruction including 20% to 40% ASIR slightly improved the conspicuity of various paediatric cardiac structures in newborns and children with respect to conventional reconstruction (filtered back-projection) alone. (orig.)

206

Proposing Cluster_Similarity Method in Order to Find as Much Better Similarities in Databases  

Directory of Open Access Journals (Sweden)

Full Text Available Different ways of entering data into databases result in duplicate records that cause increasing of databases size. This is a fact that we cannot ignore it easily. There are several methods that are used for this purpose. In this paper, we have tried to increase the accuracy of operations by using cluster similarity instead of direct similarity of fields. So that clustering is done on fields of database and according to accomplished clustering on fields, similarity degree of records is obtained. In this method by using present information in database, more logical similarity is obtained for deficient information that in general, the method of cluster similarity could improve operations 24% compared with previous methods.

Mohammad-Reza Feizi-Derakhshi

2011-09-01

207

A comparative method for finding and folding RNA secondary structures within protein-coding regions.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Existing computational methods for RNA secondary-structure prediction tacitly assume RNA to only encode functional RNA structures. However, experimental studies have revealed that some RNA sequences, e.g. compact viral genomes, can simultaneously encode functional RNA structures as well as proteins, and evidence is accumulating that this phenomenon may also be found in Eukaryotes. We here present the first comparative method, called RNA-Decoder, which explicitly takes the known protein-coding...

Pedersen, Js; Meyer, Im; Forsberg, R.; Simmonds, P.; Hein, J.

2004-01-01

208

Infant feeding experiences among teen mothers in North Carolina: Findings from a mixed-methods study  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background Adolescent mothers in the U.S. are much less likely to initiate breastfeeding than older mothers, and teens who do initiate breastfeeding tend to breastfeed for shorter durations. The purpose of this mixed-methods study is to investigate breastfeeding practices, barriers and facilitators among adolescent mothers ages 17 and younger. Methods Quantitative descriptive analyses are conducted using data from the North Carolina Pregnancy Risk Asses...

Samandari Ghazaleh; Wilson Ellen K; Tucker Christine M

2011-01-01

209

A numerical method for finding sign-changing solutions of superlinear Dirichlet problems  

Energy Technology Data Exchange (ETDEWEB)

In a recent result it was shown via a variational argument that a class of superlinear elliptic boundary value problems has at least three nontrivial solutions, a pair of one sign and one which sign changes exactly once. These three and all other nontrivial solutions are saddle points of an action functional, and are characterized as local minima of that functional restricted to a codimension one submanifold of the Hilbert space H-0-1-2, or an appropriate higher codimension subset of that manifold. In this paper, we present a numerical Sobolev steepest descent algorithm for finding these three solutions.

Neuberger, J.M.

1996-12-31

210

Improvement of range accuracy of range-gating laser radar using the centroid method.  

Science.gov (United States)

An improved processing approach based on the relation between range accuracy and slicing number is proposed to improve the range accuracy of range-gating laser radar. The sequence of time-slice images is segmented according to their optimal slicing number and processed in segments to achieve the range information of objects. Experimental results indicate that the slicing number has a significant impact on range accuracy, and the highest range accuracy can be achieved when the systems work with an optimal slicing number. PMID:20062514

Zhang, Yong; Zhao, Yuan; Liu, Liping; He, Jiang; Jin, Chenfei; Mi, Guangcan; Sun, Xiudong

2010-01-10

211

Application of the multiple PRF technique to resolve Doppler centroid estimation ambiguity for spaceborne SAR  

Science.gov (United States)

Estimation of the Doppler centroid ambiguity is a necessary element of the signal processing for SAR systems with large antenna pointing errors. Without proper resolution of the Doppler centroid estimation (DCE) ambiguity, the image quality will be degraded in the system impulse response function and the geometric fidelity. Two techniques for resolution of DCE ambiguity for the spaceborne SAR are presented; they include a brief review of the range cross-correlation technique and presentation of a new technique using multiple pulse repetition frequencies (PRFs). For SAR systems, where other performance factors control selection of the PRF's, an algorithm is devised to resolve the ambiguity that uses PRF's of arbitrary numerical values. The performance of this multiple PRF technique is analyzed based on a statistical error model. An example is presented that demonstrates for the Shuttle Imaging Radar-C (SIR-C) C-band SAR, the probability of correct ambiguity resolution is higher than 95 percent for antenna attitude errors as large as 3 deg.

Chang, C. Y.; Curlander, J. C.

1992-01-01

212

Music therapists’ practice-based research in cancer and palliative care: Creative methods and situated findings  

Directory of Open Access Journals (Sweden)

Full Text Available Although randomized controlled trials are described as the gold standard in health care research, their superiority is being questioned in palliative care which is focused on addressing individualized needs to maximize life quality. We use creative practice-based research to examine the usefulness of our music therapy work amongst people with life threatening conditions. Examined voices include “collective” (patients, visitors, staff, and music therapist, "their” (patients or caregivers, "our” (a group of music therapists, and "my voice” (one music therapist. Data sources have included clinical journals, semi-structured questionnaires, interview responses, a focus group, reflexive groupwork supervision transcripts, and patients’ song lyrics. Findings, situated within varied theoretic lenses, substantiate music therapy’s role in oncology and palliative care settings. Readers are invited to devise creative ways to voice their clients’, bystanders’, and own wisdom about music therapy to meaningfully extend the knowledge base.

Philippa Barry

2009-11-01

213

NCI: SBIR & STTR - Find Funding - Contracts - 264 Novel and Improved Methods for Detecting Epigenetic Modifications  

Science.gov (United States)

Epigenetic markers have shown promise for early detection and diagnosis of cancerous lesions. However, it is unlikely that any single epigenetic marker has sufficient sensitivity and specificity to accurately and reliably detect early cancers, or to predict cancer risk and progression. Also, methods used to measure epigenetic modifications need to be improved to increase specificity, sensitivity, reproducibility, and throughput.

214

Finding the "g"-Factor in Brain Structure Using the Method of Correlated Vectors  

Science.gov (United States)

It is unclear whether brain mechanisms underlying human intelligence are distributed throughout the brain or mainly concentrated in the frontal lobes. Data are inconsistent possibly due, at least in part, to the different ways the construct of intelligence is measured. Here we apply the method of correlated vectors to determine how the general…

Colom, Roberto; Jung, Rex E.; Haier, Richard J.

2006-01-01

215

The Dynamics of Poverty in the United States: A Review of Data, Methods, and Findings  

Science.gov (United States)

This paper reviews the literature on poverty dynamics in the U.S. It surveys the most prevalent data, theories, and methods used to answer three key questions: How likely are people to enter, exit, and reenter poverty? How long do people remain in poverty? And what events are associated with entering and exiting poverty? The paper then analyzes…

Cellini, Stephanie Riegg; McKernan, Signe-Mary; Ratcliffe, Caroline

2008-01-01

216

A Simple Method to Find out when an Ordinary Differential Equation Is Separable  

Science.gov (United States)

We present an alternative method to that of Scott (D. Scott, "When is an ordinary differential equation separable?", "Amer. Math. Monthly" 92 (1985), pp. 422-423) to teach the students how to discover whether a differential equation y[prime] = f(x,y) is separable or not when the nonlinearity f(x, y) is not explicitly factorized. Our approach is…

Cid, Jose Angel

2009-01-01

217

Finding a fox: an evaluation of survey methods to estimate abundance of a small desert carnivore.  

Science.gov (United States)

The status of many carnivore species is a growing concern for wildlife agencies, conservation organizations, and the general public. Historically, kit foxes (Vulpes macrotis) were classified as abundant and distributed in the desert and semi-arid regions of southwestern North America, but is now considered rare throughout its range. Survey methods have been evaluated for kit foxes, but often in populations where abundance is high and there is little consensus on which technique is best to monitor abundance. We conducted a 2-year study to evaluate four survey methods (scat deposition surveys, scent station surveys, spotlight survey, and trapping) for detecting kit foxes and measuring fox abundance. We determined the probability of detection for each method, and examined the correlation between the relative abundance as estimated by each survey method and the known minimum kit fox abundance as determined by radio-collared animals. All surveys were conducted on 15 5-km transects during the 3 biological seasons of the kit fox. Scat deposition surveys had both the highest detection probabilities (p?=?0.88) and were most closely related to minimum known fox abundance (r2?=?0.50, P?=?0.001). The next best method for kit fox detection was the scent station survey (p?=?0.73), which had the second highest correlation to fox abundance (r2?=?0.46, Pscat deposition transects during the breeding season. Scat deposition surveys have low costs, resilience to weather, low labor requirements, and pose no risk to the study animals. The breeding season was ideal for monitoring kit fox population size, as detections consisted of the resident population and had the highest detection probabilities. Using appropriate monitoring techniques will be critical for future conservation actions for this rare desert carnivore. PMID:25148102

Dempsey, Steven J; Gese, Eric M; Kluever, Bryan M

2014-01-01

218

THE STATISTICAL METHOD FOR FINDING THE RESPONSE FOR N RANDOM EXCITATION OF THE INVERTED PENDULUM  

Directory of Open Access Journals (Sweden)

Full Text Available We present a method for estimating the power spectral density of the stationary response of oscillatorwith a nonlinear restoring force under external stochastic wide-band excitation. An equivalent linear system isderived, from which the power spectral density is deduced. We consider an inverted pendulum suspendedsubjected to white noise excitation with a random number n random excitations simultaneously applied. Themethod will be briefly discussed in the following sections

Marinic? STAN

2013-05-01

219

THE STATISTICAL METHOD FOR FINDING THE RESPONSE FOR N RANDOM EXCITATION OF THE INVERTED PENDULUM  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present a method for estimating the power spectral density of the stationary response of oscillatorwith a nonlinear restoring force under external stochastic wide-band excitation. An equivalent linear system isderived, from which the power spectral density is deduced. We consider an inverted pendulum suspendedsubjected to white noise excitation with a random number n random excitations simultaneously applied. Themethod will be briefly discussed in the following sections

Stan, Marinica?; Stan, Petre

2013-01-01

220

Paediatric cardiac CT examinations: impact of the iterative reconstruction method ASIR on image quality - preliminary findings  

Energy Technology Data Exchange (ETDEWEB)

Radiation dose exposure is of particular concern in children due to the possible harmful effects of ionizing radiation. The adaptive statistical iterative reconstruction (ASIR) method is a promising new technique that reduces image noise and produces better overall image quality compared with routine-dose contrast-enhanced methods. To assess the benefits of ASIR on the diagnostic image quality in paediatric cardiac CT examinations. Four paediatric radiologists based at two major hospitals evaluated ten low-dose paediatric cardiac examinations (80 kVp, CTDI{sub vol} 4.8-7.9 mGy, DLP 37.1-178.9 mGy.cm). The average age of the cohort studied was 2.6 years (range 1 day to 7 years). Acquisitions were performed on a 64-MDCT scanner. All images were reconstructed at various ASIR percentages (0-100%). For each examination, radiologists scored 19 anatomical structures using the relative visual grading analysis method. To estimate the potential for dose reduction, acquisitions were also performed on a Catphan phantom and a paediatric phantom. The best image quality for all clinical images was obtained with 20% and 40% ASIR (p < 0.001) whereas with ASIR above 50%, image quality significantly decreased (p < 0.001). With 100% ASIR, a strong noise-free appearance of the structures reduced image conspicuity. A potential for dose reduction of about 36% is predicted for a 2- to 3-year-old child when using 40% ASIR rather than the standard filtered back-projection method. Reconstruction including 20% to 40% ASIR slightly improved the conspicuity of various paediatric cardiac structures in newborns and children with respect to conventional reconstruction (filtered back-projection) alone. (orig.)

Mieville, Frederic A. [University Hospital Center and University of Lausanne, Institute of Radiation Physics, Lausanne (Switzerland); University Hospital Center and University of Lausanne, Institute of Radiation Physics - Medical Radiology, Lausanne (Switzerland); Gudinchet, Francois; Rizzo, Elena [University Hospital Center and University of Lausanne, Department of Radiology, Lausanne (Switzerland); Ou, Phalla; Brunelle, Francis [Necker Children' s Hospital, Department of Radiology, Paris (France); Bochud, Francois O.; Verdun, Francis R. [University Hospital Center and University of Lausanne, Institute of Radiation Physics, Lausanne (Switzerland)

2011-09-15

 
 
 
 
221

FINDING CRITICAL BUCKLING LOAD OF RECTANGULAR PLATE USING INTEGRATED FORCE METHOD  

Directory of Open Access Journals (Sweden)

Full Text Available A method which couples equilibrium equations and compatibility conditions that are developed based on equilibrium equations by using a systematic concatenation procedure is proposed here for the plate buckling analysis. A RECT_9F_12D plate bending element having 9 force unknowns and 12 displacement degrees of freedom is used with the necessary matrix formulation based on the Integrated Force Method (IFM. The geometric stiffness matrix required for buckling analysis is explicitly derived. Matlab software is used to develop compatibility conditions whereas other calculations are carried out in a program developed in VB.NET. A rectangular plate under uniaxial loading is analysed under 7 different boundary conditions. A case of biaxial loading of simply supported plate with loading ratio equals to one is also attempted using the proposed formulation. Results are obtained by considering either 2 x 2 discretization of quarter plate or 4 x 2 discretization of half plate depending upon the type of symmetry available based on support conditions. Results are compared with the available classical solutions to demonstrate the effectiveness of the proposed method; a good agreement is indicated.

S. C. Patodi

2012-11-01

222

Adaptive Ant Colony Clustering Method Applied to Finding Closely Communicating Community  

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Full Text Available The investigation of community structures in networks is an important issue in many domains and disciplines. Closely communicating community is different from the traditional community which emphasize particularly on structure or context. Our previous method played more emphasis on the feasibility that ant colony algorithm applied to community detection. However the essence of closely communicating community did not be described clearly. In this paper, the de?nition of closely communicating community is put forward ?rstly, the four features are described and corresponding methods are introduced to achieve the value of features between each pair. Meanwhile, pair propinquity and local propinquity are put forward and used to guide ants’ decision. Based on the previous work, the closely communicating community detection method is improved in four aspects of adaptive adjusting, which are entropy based weight modulation, combining historical paths and random wandering to select next coordination, the strategy of forcing unloading and the adaptive change of ant’s eyesight. The value selection of parameters is discussed in the portion of experiments, and the results also reveal the improvement of our algorithm in adaptive djusting.

Yan Liu

2012-02-01

223

A method for finding the optimal predictor indices for local wave climate conditions  

Science.gov (United States)

In this study, a method to obtain local wave predictor indices that take into account the wave generation process is described and applied to several locations. The method is based on a statistical model that relates significant wave height with an atmospheric predictor, defined by sea level pressure fields. The predictor is composed of a local and a regional part, representing the sea and the swell wave components, respectively. The spatial domain of the predictor is determined using the Evaluation of Source and Travel-time of wave Energy reaching a Local Area (ESTELA) method. The regional component of the predictor includes the recent historical atmospheric conditions responsible for the swell wave component at the target point. The regional predictor component has a historical temporal coverage ( n-days) different to the local predictor component (daily coverage). Principal component analysis is applied to the daily predictor in order to detect the dominant variability patterns and their temporal coefficients. Multivariate regression model, fitted at daily scale for different n-days of the regional predictor, determines the optimum historical coverage. The monthly wave predictor indices are selected applying a regression model using the monthly values of the principal components of the daily predictor, with the optimum temporal coverage for the regional predictor. The daily predictor can be used in wave climate projections, while the monthly predictor can help to understand wave climate variability or long-term coastal morphodynamic anomalies.

Camus, Paula; Méndez, Fernando J.; Losada, Inigo J.; Menéndez, Melisa; Espejo, Antonio; Pérez, Jorge; Rueda, Ana; Guanche, Yanira

2014-07-01

224

Centroid-Point of Ranking Fuzzy Numbers and Its Application to Health Related Quality of Life Indicators  

Directory of Open Access Journals (Sweden)

Full Text Available Ranking of fuzzy numbers is not an easy task as fuzzy numbers are represented by possibility distributions and they can overlap with each other. Since it was introduced, various approaches on ranking fuzzy numbers have been proposed. The recent ranking fuzzy numbers proposed by Wang and Li is claimed to be the improved version in ranking. However, the method was never been simplified and tested in real life application. This paper presents a four-step computation ofranking fuzzy numbers and its application in ranking indicatorsof health related quality of life. The four steps algorithm was proposed as to establish ranking and followed by a testimony inhealth related symptoms among elderly. Data in form of linguistic terms were collected from three experts at State of Terengganu Malaysia. Decisions were made based on the centroid-point ( x, y , where the degree of representative location ( x is higher than average height ( y . These points permit to characterize the evaluation behaviour of each indicator. The ranking reflects the problematic level of elderly people. The results show the feasibility of the proposed stepwise computation in real application.

Lazim Abdullah,

2010-11-01

225

A comparison of companion matrix methods to find roots of a trigonometric polynomial  

Science.gov (United States)

A trigonometric polynomial is a truncated Fourier series of the form fN(t)??j=0Naj cos(jt)+?j=1N bj sin(jt). It has been previously shown by the author that zeros of such a polynomial can be computed as the eigenvalues of a companion matrix with elements which are complex valued combinations of the Fourier coefficients, the "CCM" method. However, previous work provided no examples, so one goal of this new work is to experimentally test the CCM method. A second goal is introduce a new alternative, the elimination/Chebyshev algorithm, and experimentally compare it with the CCM scheme. The elimination/Chebyshev matrix (ECM) algorithm yields a companion matrix with real-valued elements, albeit at the price of usefulness only for real roots. The new elimination scheme first converts the trigonometric rootfinding problem to a pair of polynomial equations in the variables (c,s) where c?cos(t) and s?sin(t). The elimination method next reduces the system to a single univariate polynomial P(c). We show that this same polynomial is the resultant of the system and is also a generator of the Groebner basis with lexicographic ordering for the system. Both methods give very high numerical accuracy for real-valued roots, typically at least 11 decimal places in Matlab/IEEE 754 16 digit floating point arithmetic. The CCM algorithm is typically one or two decimal places more accurate, though these differences disappear if the roots are "Newton-polished" by a single Newton's iteration. The complex-valued matrix is accurate for complex-valued roots, too, though accuracy decreases with the magnitude of the imaginary part of the root. The cost of both methods scales as O(N3) floating point operations. In spite of intimate connections of the elimination/Chebyshev scheme to two well-established technologies for solving systems of equations, resultants and Groebner bases, and the advantages of using only real-valued arithmetic to obtain a companion matrix with real-valued elements, the ECM algorithm is noticeably inferior to the complex-valued companion matrix in simplicity, ease of programming, and accuracy.

Boyd, John P.

2013-08-01

226

ALGORITHM FOR FINDING EFFECTIVE FORMS AND METHODS OF TRADE ACTIVATION AND OPTIMIZATION OF FOREIGN UKRAINE  

Directory of Open Access Journals (Sweden)

Full Text Available  The Fundamental and applied problems of activation and optimization of foreign economic activity is choice of effective forms and methods of realization of external economic point-of-sale operations. In this context, on the basis of the Ukrainian legislation and economic literature, it is formulated and generalized them teoretiko-methodological essence, and also separate features which can serve as the economic instruments of activation and optimization of foreign economic activity of Ukraine are marked. Generalized methodological properties of algorithms and the schematic algorithm of search of economic instruments of activation and optimization of foreign economic activity of Ukraine is developed.

?.?. ??????

2011-12-01

227

A comparative method for finding and folding RNA secondary structures within protein-coding regions  

DEFF Research Database (Denmark)

Existing computational methods for RNA secondary-structure prediction tacitly assume RNA to only encode functional RNA structures. However, experimental studies have revealed that some RNA sequences, e.g. compact viral genomes, can simultaneously encode functional RNA structures as well as proteins, and evidence is accumulating that this phenomenon may also be found in Eukaryotes. We here present the first comparative method, called RNA-DECODER, which explicitly takes the known protein-coding context of an RNA-sequence alignment into account in order to predict evolutionarily conserved secondary-structure elements, which may span both coding and non-coding regions. RNA-DECODER employs a stochastic context-free grammar together with a set of carefully devised phylogenetic substitution-models, which can disentangle and evaluate the different kinds of overlapping evolutionary constraints which arise. We show that RNA-DECODER's parameters can be automatically trained to successfully fold known secondary structures within the HCV genome. We scan the genomes of HCV and polio virus for conserved secondary-structure elements, and analyze performance as a function of available evolutionary information. On known secondary structures, RNA-DECODER shows a sensitivity similar to the programs MFOLD, PFOLD and RNAALIFOLD. When scanning the entire genomes of HCV and polio virus for structure elements, RNA-DECODER's results indicate a markedly higher specificity than MFOLD, PFOLD and RNAALIFOLD.

Pedersen, Jakob Skou; Meyer, Irmtraud Margret

2004-01-01

228

Application of geo-microbial prospecting method for finding oil and gas reservoirs  

Science.gov (United States)

Microbial prospecting of hydrocarbons is based on the detection of anomalous population of hydrocarbon oxidizing bacteria in the surface soils, indicates the presence of subsurface oil and gas accumulation. The technique is based on the seepage of light hydrocarbon gases such as C1-C4 from the oil and gas pools to the shallow surface that provide the suitable conditions for the development of highly specialized bacterial population. These bacteria utilize hydrocarbon gases as their only food source and are found enriched in the near surface soils above the hydrocarbon bearing structures. The methodology involves the collection of soil samples from the survey area, packing, preservation and storage of samples in pre-sterilized sample bags under aseptic and cold conditions till analysis and isolation and enumeration of hydrocarbon utilizing bacteria such as methane, ethane, propane, and butane oxidizers. The contour maps for the population density of hydrocarbon oxidizing bacteria are drawn and the data can be integrated with geological, geochemical, geophysical methods to evaluate the hydrocarbon prospect of an area and to prioritize the drilling locations thereby reducing the drilling risks and achieve higher success in petroleum exploration. Microbial Prospecting for Oil and Gas (MPOG) method success rate has been reported to be 90%. The paper presents details of microbial prospecting for oil and gas studies, excellent methodology, future development trends, scope, results of study area, case studies and advantages.

Rasheed, M. A.; Hasan, Syed Zaheer; Rao, P. L. Srinivasa; Boruah, Annapurna; Sudarshan, V.; Kumar, B.; Harinarayana, T.

2014-07-01

229

A Vision based Geometrical Method to find Fingers Positions in Real Time Hand Gesture Recognition  

Directory of Open Access Journals (Sweden)

Full Text Available A novel method to calculate the bended finger’s angle has presented here which could be used to control the electro-mechanical robotic hand. It is assumed that the robotic hand has the human hand like joints and same number of degree of freedom as human hand. In many applications an equipment like human hand is needed, to do the same kind of operation like human do. These days it is easy to make the electro-mechanical robotic hand which has five fingers and same joint but it is not easily controllable as the human hand for accurate work. In our method the hand gesture will be interpreted for controlling the robotic hand. The angles for all the fingers will be calculated and that could be further passed to the robotic hand for controlling its finger. User would perform gesture according to the action as he wants to be done by robotic hand. Here finger positions are detected using geometric modeling of hand in the extracted image Region of interest cropping from the image made the algorithm faster.

Ankit Chaudhary

2012-04-01

230

Three-Dimensional Computed Tomography as a Method for Finding Die Attach Voids in Diodes  

Science.gov (United States)

NASA analyzes electrical, electronic, and electromechanical (EEE) parts used in space vehicles to understand failure modes of these components. The diode is an EEE part critical to NASA missions that can fail due to excessive voiding in the die attach. Metallography, one established method for studying the die attach, is a time-intensive, destructive, and equivocal process whereby mechanical grinding of the diodes is performed to reveal voiding in the die attach. Problems such as die attach pull-out tend to complicate results and can lead to erroneous conclusions. The objective of this study is to determine if three-dimensional computed tomography (3DCT), a nondestructive technique, is a viable alternative to metallography for detecting die attach voiding. The die attach voiding in two- dimensional planes created from 3DCT scans was compared to several physical cross sections of the same diode to determine if the 3DCT scan accurately recreates die attach volumetric variability

Brahm, E. N.; Rolin, T. D.

2010-01-01

231

A screening pattern recognition method finds new and divergent targets for drugs and natural products.  

Science.gov (United States)

Computational target prediction methods using chemical descriptors have been applied exhaustively in drug discovery to elucidate the mechanisms-of-action (MOAs) of small molecules. To predict truly novel and unexpected small molecule-target interactions, compounds must be compared by means other than their chemical structure alone. Here we investigated predictions made by a method, HTS fingerprints (HTSFPs), that matches patterns of activities in experimental screens. Over 1,400 drugs and 1,300 natural products (NPs) were screened in more than 200 diverse assays, creating encodable activity patterns. The comparison of these activity patterns to an MOA-annotated reference panel led to the prediction of 5,281 and 2,798 previously unknown targets for the NP and drug sets, respectively. Intriguingly, there was limited overlap among the targets predicted; the drugs were more biased toward membrane receptors and the NPs toward soluble enzymes, consistent with the idea that they represent unexplored pharmacologies. Importantly, HTSFPs inferred targets that were beyond the prediction capabilities of standard chemical descriptors, especially for NPs but also for the more explored drug set. Of 65 drug-target predictions that we tested in vitro, 48 (73.8%) were confirmed with AC50 values ranging from 38 nM to 29 ?M. Among these interactions was the inhibition of cyclooxygenases 1 and 2 by the HIV protease inhibitor Tipranavir. These newly discovered targets that are phylogenetically and phylochemically distant to the primary target provide an explanation for spontaneous bleeding events observed for patients treated with this drug, a physiological effect that was previously difficult to reconcile with the drug's known MOA. PMID:24802392

Wassermann, Anne Mai; Lounkine, Eugen; Urban, Laszlo; Whitebread, Steven; Chen, Shanni; Hughes, Kevin; Guo, Hongqiu; Kutlina, Elena; Fekete, Alexander; Klumpp, Martin; Glick, Meir

2014-07-18

232

Finding an optimal method for imaging lymphatic vessels of the upper limb  

Energy Technology Data Exchange (ETDEWEB)

Lymphoscintigraphy involves interstitial injection of radiolabelled particulate materials or radioproteins. Although several variations in the technique have been described, their place in clinical practice remains controversial. Traditional diagnostic criteria are based primarily on lymph node appearances but in situations such as breast cancer, where lymph nodes may have been excised, these criteria are of limited use. In these circumstances, lymphatic vessel morphology takes on greater importance as a clinical endpoint, so a method that gives good definition of lymphatic vessels would be useful. In patients with breast cancer, for example, such a method, used before and after lymph node resection, may assist in predicting the development of breast cancer-related lymphoedema. The aim of this study was to optimise a method for the visualisation of lymphatic vessels. Subcutaneous (sc) and intradermal (id) injection sites were compared, and technetium-99m nanocolloid, a particulate material, was compared with {sup 99m}Tc-human immunoglobulin (HIG), which is a soluble macromolecule. Twelve normal volunteers were each studied on two occasions. In three subjects, id {sup 99m}Tc-HIG was compared with sc {sup 99m}Tc-HIG, in three id {sup 99m}Tc-nanocolloid was compared with sc {sup 99m}Tc-nanocolloid, in three id {sup 99m}Tc-HIG was compared with id {sup 99m}Tc-nanocolloid and in three sc {sup 99m}Tc-HIG was compared with sc {sup 99m}Tc-nanocolloid. Endpoints were quality of lymphatic vessel definition, the time after injection at which vessels were most clearly visualised, the rate constant of depot disappearance (k) and the systemic blood accumulation rate as measured by gamma camera imaging over the liver or cardiac blood pool. Excellent definition of lymphatic vessels was obtained following id injection of either radiopharmaceutical, an injection route that was clearly superior to sc. Differences between radiopharmaceuticals were less clear, although after id injection, {sup 99m}Tc-HIG gave images that were marginally but significantly better than those given by {sup 99m}Tc-nanocolloid. Image quality correlated inversely with time after injection at which the best image was obtained, consistent with the notion that good vessel definition was dependent on a ''narrow'' bolus width. k was approximately three times higher after id injection than after sc injection but it was not significantly different between radiopharmaceuticals for either injection route. Intradermal {sup 99m}Tc-HIG gave a cardiac blood pool signal that, over the first 60 min, increased about five times faster than that with sc {sup 99m}Tc-HIG, but no clear difference was observed in the rate of increase in hepatic activity between id {sup 99m}Tc-nanocolloid and sc {sup 99m}Tc-nanocolloid. We conclude that id injection provides rapid access of radiotracers to lymphatic vessels, which is ideal for imaging lymphatic vessel morphology. {sup 99m}Tc-HIG is marginally superior to nanocolloid for this purpose and, in drainage basins from which lymph nodes have been excised, is not handicapped by a potentially inferior ability, compared with radiocolloid, to image lymph nodes. (orig.)

O' Mahony, Susan; Purushotham, Arnie D. [Cambridge Breast Unit, Addenbrooke' s Hospital, Cambridge (United Kingdom); Rose, Sarah L.; Chilvers, Alison J.; Ballinger, James R.; Solanki, Chandra K.; Barber, Robert W.; Peters, A. Michael [Department of Nuclear Medicine, Addenbrooke' s Hospital, Hills Road, CB2 2QQ, Cambridge (United Kingdom); Mortimer, Peter S. [Department of Medicine, St George' s Hospital, London (United Kingdom)

2004-04-01

233

Lead finding from Pterocarpous santilanus with hepatoprotective potentials through in silico methods  

Directory of Open Access Journals (Sweden)

Full Text Available Review of the literature revealed that, many compounds have been isolated from P.santalinus but there is no report of screening its potency in protecting CCl4 induced liver damage. Hence in the present study an attempt has been made to study the hepatoprotective potency of the active constituents in P.santalinus through in silico methods.Lipenski’s Rule of Five was applied on all the compounds to evaluate their drug likeness and pharmacological properties. Only the compounds satisfying the Lipenski’s criteria were considered for further computational operations. Compounds that cleared the Lipenski’s barrier were prepared for docking studies by their energyminimization in Marvin Sketch. HBx protein of hepatitis B virus served as a target (receptor for docking studies. Its structure was retrieved from PDB (ID:3I7H. Energy minimized compounds were subjected to receptor-ligand interaction study using Hex docking tool. Based on the docking scores of energy minimized compounds it wasconcluded that pterocarpol and cryptomeridiol required minimum energy to bind to HBx. ADME-TOX analysis of these compounds showed that their AMES test value was significantly lower than some of the ommercially and widely used drugs to treat Hepatisis. Hence these compounds hold good prospective of being used as medicine thattargets HBx for hepatitis treatment.

B.K.Manjunatha

2010-08-01

234

Influence of various treatment methods on bacteriological findings in cows with puerperal endometritis.  

Science.gov (United States)

The aim of the study was to identify the species of microorganisms isolated from the uterus of healthy cows (control group) and cows affected with puerperal metritis (PM) before and after an experimental therapy with an immunomodulator and antibiotics versus commonly applied methods (antibiotic + beta-blocker or antibiotic + PGF2alpha). Examinations were carried out on 110 cows with PM in three farms with similar system of rearing and nutrition. The control group consisted of 21 cows without postpartum disturbances. Smears from the uterus were taken before treatment and then at 21st day of observation. Escherichia coli and other species of Enterobacteriaceae family were isolated from 48.2% of PM cows and 47.6% of healthy cows. The degree of Arcanobacterium pyogenes infection was statistically lower in healthy than in sick cows (9.5% versus 30.0%). Streptococcus sp. was isolated from 13.6% of PM cows and from 16% of control ones. Staphylococci were isolated from 10% of PM and from 30% of control cows. Other bacteria species were isolated from about 10% of the examined cows. The best elimination of infections (66%) was noted in cows treated with the intrauterine antibiotic in combination with PGF2alpha i.m. injection. Examination showed that species of bacteria in the postparturient uterus were similar in healthy and sick cows. However, Arcanobacterium pyogenes was isolated 3 times more often from the sick animals. This pathogen was identified in 11 cows out of 19 (57.9%) culled subsequently because of infertility after the metritis puerperalis was clinically cured. PMID:15478861

Kaczmarowski, M; Malinowski, E; Markiewicz, H

2004-01-01

235

An efficient method to find potentially universal population genetic markers, applied to metazoans  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Despite the impressive growth of sequence databases, the limited availability of nuclear markers that are sufficiently polymorphic for population genetics and phylogeography and applicable across various phyla restricts many potential studies, particularly in non-model organisms. Numerous introns have invariant positions among kingdoms, providing a potential source for such markers. Unfortunately, most of the few known EPIC (Exon Primed Intron Crossing loci are restricted to vertebrates or belong to multigenic families. Results In order to develop markers with broad applicability, we designed a bioinformatic approach aimed at avoiding multigenic families while identifying intron positions conserved across metazoan phyla. We developed a program facilitating the identification of EPIC loci which allowed slight variation in intron position. From the Homolens databases we selected 29 gene families which contained 52 promising introns for which we designed 93 primer pairs. PCR tests were performed on several ascidians, echinoderms, bivalves and cnidarians. On average, 24 different introns per genus were amplified in bilaterians. Remarkably, five of the introns successfully amplified in all of the metazoan genera tested (a dozen genera, including cnidarians. The influence of several factors on amplification success was investigated. Success rate was not related to the phylogenetic relatedness of a taxon to the groups that most influenced primer design, showing that these EPIC markers are extremely conserved in animals. Conclusions Our new method now makes it possible to (i rapidly isolate a set of EPIC markers for any phylum, even outside the animal kingdom, and thus, (ii compare genetic diversity at potentially homologous polymorphic loci between divergent taxa.

Chenuil Anne

2010-09-01

236

Path integral centroid molecular dynamics simulations of semiinfinite slab and bulk liquid of para-hydrogen  

Energy Technology Data Exchange (ETDEWEB)

It has been unsuccessful to solve a set of time-dependent Schroedinger equations numerically for many-body quantum systems which involve, e.g., a number of hydrogen molecules, protons, and excess electrons at a low temperature, where quantum effect evidently appears. This undesirable situation is fatal for the investigation of real low-temperature chemical systems because they are essentially composed of many quantum degrees of freedom. However, if we use a new technique called `path integral centroid molecular dynamics (CMD) simulation` proposed by Cao and Voth in 1994, the real-time semi-classical dynamics of many degrees of freedom can be computed by utilizing the techniques already developed in the traditional classical molecular dynamics (MD) simulations. Therefore, the CMD simulation is expected to be very powerful tool for the quantum dynamics studies or real substances. (J.P.N.)

Kinugawa, Kenichi [Nara Women`s Univ., Nara (Japan). Dept. of Chemistry

1998-10-01

237

Luminescence properties, centroid shift and energy transfer of Ce3+ in aqueous chloride solutions  

International Nuclear Information System (INIS)

This paper focuses upon three themes: all related to aqueous cerium chloride solutions. First, the features in the absorption spectra of CeCl3 solutions do not shift noticeably with concentration and are at similar energies to bands in the solid-state absorption spectrum of Ce(H2O)93+, with the exception of the weak band at 297 nm which is due to Ce(H2O)83+. The broad emission band in solution is only due to [Ce(H2O)83+]? and the emission quenches at concentrations >0.06 M. Bands in the excitation spectra of aqueous CeCl3 solutions apparently change position with increasing concentration, due to absorption by Ce(H2O)93+ which does not contribute to emission. At concentrations above 1 M, there is total extinction of incident radiation for wavelengths shorter than 310 nm. Second, this system is chosen to illustrate the revised calculation of centroid shift, by taking into account the vibronic nature of spectral features, in contrast with the pure electronic transition of the free ion. Similar calculations are applicable to other Ce3+ systems. Thirdly, excitation spectra are employed to demonstrate the energy transfer occurring from Ce3+ to Tb3+ and Eu3+ in aqueous chloride solutions, which is an unusual energy transfer, occurring from 5d to 4f states and between hydrated lanthanide ions in solution. -- Highlights: • Excitation spectra of aqueous CeCl3 reveal photodissociation and emission only from [Ce(H2O)83+]?. • Revised calculation of centroid shift is given for general cases. • Excitation spectra demonstrate the energy transfer occurring from Ce3+ to Tb3+ and Eu3+ in aqueous chloride solutions. • This is an unusual energy transfer, occurring from 5d to 4f states and between hydrated lanthanide ions in solution

238

Pipeline structure for real-time centroid calculation of Hartmann wavefront sensor with horizontal multi-channel pixel output  

Science.gov (United States)

In this paper, a real-time pipeline centroid calculating structure based on programmable logic devices is designed for Hartmann wavefront sensor with horizontal multi-channel pixel output. The pipeline consists of modularized cells including multiplier groups, accumulation cells, dividers and corresponding control units. The structure is specially designed to deal with simultaneously output pixels which belong to two adjacent subapertures as well as those pixels belong to the same subaperture. When the number of output channels is 8 and pixels output at 80MHz clock frequency, centroid calculation latency in simulation is less than 0.5?s.

Wang, Shaobai; Wang, Chunhong; Rao, Changhui

2011-08-01

239

The Shortlist Method for Fast Computation of the Earth Mover's Distance and Finding Optimal Solutions to Transportation Problems  

Science.gov (United States)

Finding solutions to the classical transportation problem is of great importance, since this optimization problem arises in many engineering and computer science applications. Especially the Earth Mover's Distance is used in a plethora of applications ranging from content-based image retrieval, shape matching, fingerprint recognition, object tracking and phishing web page detection to computing color differences in linguistics and biology. Our starting point is the well-known revised simplex algorithm, which iteratively improves a feasible solution to optimality. The Shortlist Method that we propose substantially reduces the number of candidates inspected for improving the solution, while at the same time balancing the number of pivots required. Tests on simulated benchmarks demonstrate a considerable reduction in computation time for the new method as compared to the usual revised simplex algorithm implemented with state-of-the-art initialization and pivot strategies. As a consequence, the Shortlist Method facilitates the computation of large scale transportation problems in viable time. In addition we describe a novel method for finding an initial feasible solution which we coin Modified Russell's Method. PMID:25310106

Gottschlich, Carsten; Schuhmacher, Dominic

2014-01-01

240

The 3-D tectonic stress fields in and around Japan inverted from centroid moment tensor data of seismic events  

Science.gov (United States)

We can regard the occurrence of earthquakes as the partial release of tectonic stress by sudden brittle rupture. In the framework of linear elasticity, any indigenous source including earthquake rupture is represented by a moment tensor. The moment tensor is mathematically equivalent to the volume integral of stress release over the whole elastic region surrounding the source, and so we can quantitatively relate the centroid moment tensor (CMT) of seismic events with an unknown tectonic stress field. On the basis of such an idea and Bayesian statistical inference theory, we developed an inversion method to estimate the 3-D pattern of tectonic stress from CMT data. Applying the CMT data inversion method to 12,500 seismic events in and around Japan, we obtained precise 3-D tectonic stress patterns that illuminate the present-day (Quaternary) complex tectonic motion of Japanese islands. The stress pattern of the Kuril-Japan-Nankai arc is basically E-W compression, but the direction of intermediate principal stress changes from N-S (reverse faulting type) in northeast Japan to vertical (strike-slip faulting type) in southwest Japan. On the other hand, the stress pattern of the Ryukyu and Izu-Bonin back-arc regions is basically trench perpendicular tension (normal faulting type). In addition to these basic stress patterns governed by mechanical interaction between the Eurasian, North American, Pacific, and Philippine Sea plates, we can recognize several characteristic local stress patterns corresponding to the horizontal motion of the Kuril fore-arc sliver, the collision of the Izu Peninsula with the mainland of Japan, and the opening of the Beppu-Shimabara rift zone.

Terakawa, Toshiko; Matsu'Ura, Mitsuhiro

2010-12-01

 
 
 
 
241

Luminescence properties, centroid shift and energy transfer of Ce{sup 3+} in aqueous chloride solutions  

Energy Technology Data Exchange (ETDEWEB)

This paper focuses upon three themes: all related to aqueous cerium chloride solutions. First, the features in the absorption spectra of CeCl{sub 3} solutions do not shift noticeably with concentration and are at similar energies to bands in the solid-state absorption spectrum of Ce(H{sub 2}O){sub 9}{sup 3+}, with the exception of the weak band at 297 nm which is due to Ce(H{sub 2}O){sub 8}{sup 3+}. The broad emission band in solution is only due to [Ce(H{sub 2}O){sub 8}{sup 3+}]{sup ?} and the emission quenches at concentrations >0.06 M. Bands in the excitation spectra of aqueous CeCl{sub 3} solutions apparently change position with increasing concentration, due to absorption by Ce(H{sub 2}O){sub 9}{sup 3+} which does not contribute to emission. At concentrations above 1 M, there is total extinction of incident radiation for wavelengths shorter than 310 nm. Second, this system is chosen to illustrate the revised calculation of centroid shift, by taking into account the vibronic nature of spectral features, in contrast with the pure electronic transition of the free ion. Similar calculations are applicable to other Ce{sup 3+} systems. Thirdly, excitation spectra are employed to demonstrate the energy transfer occurring from Ce{sup 3+} to Tb{sup 3+} and Eu{sup 3+} in aqueous chloride solutions, which is an unusual energy transfer, occurring from 5d to 4f states and between hydrated lanthanide ions in solution. -- Highlights: • Excitation spectra of aqueous CeCl{sub 3} reveal photodissociation and emission only from [Ce(H{sub 2}O){sub 8}{sup 3+}]{sup ?}. • Revised calculation of centroid shift is given for general cases. • Excitation spectra demonstrate the energy transfer occurring from Ce{sup 3+} to Tb{sup 3+} and Eu{sup 3+} in aqueous chloride solutions. • This is an unusual energy transfer, occurring from 5d to 4f states and between hydrated lanthanide ions in solution.

Wang, Jiwei; Mei, Yong [Faculty of Physics, Liaoning University, Shenyang 110036 (China); Tanner, Peter A., E-mail: peter.a.tanner@gmail.com [Department of Science and Environmental Studies, The Hong Kong Institute of Education, 10 Lo Ping Road, Tai Po, New Territories, Hong Kong S. A. R. (China)

2014-02-15

242

Kinetic and thermodynamic parameters of biodiesel oxidation with synthetic antioxidants: simplex centroid mixture design  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese A influência da temperatura sobre a oxidação de biodiesel foi avaliada pelos parâmetros cinéticos e termodinâmicos do biocombustível de óleo de soja e gordura suína com antioxidantes sintéticos: 3-terc-butil-4-hidroxianisol (BHA), 3,5-di-terc-butil-hidroxitolueno (BHT), 2-terc-butil-hidroquinona (TB [...] HQ) e galato de propila (PG), de acordo com delineamento de mistura simplex-centróide. Os parâmetros cinéticos foram determinados considerando-se reação de primeira ordem e aplicando a equação de Arrhenius. A adição de antioxidantes promoveu o aumento da energia de ativação (Ea), sendo TBHQ e PG os mais eficientes, apresentando efeito sinérgico. BHT e BHA foram os menos eficientes, assim como suas misturas. Os parâmetros termodinâmicos de ativação, avaliados pela equação de Eyring, não indicaram processos espontâneos (?G‡ > 0) com valores de ?H‡ positivos, e ?S‡ positivos e negativos. O delineamento simplex-centróide indicou valor otimizado de 174,46 kJ mol-1 para a mistura contendo 33,33 e 66,67% de TBHQ e PG, respectivamente. Abstract in english Temperature's influence on biodiesel oxidation was evaluated by kinetic and thermodynamic data in biofuel from soybean oil and lard with synthetic antioxidants: butylatedhydroxyanisol (BHA), butylatedhydroxytoluene (BHT), tert-butylhydroquinone (TBHQ), and propylgallate (PG) by simplex centroid mixt [...] ure design. The kinetic parameters ware obtained by Arrhenius equation and showed that addition of antioxidants in all tests increased activation energy (Ea) and that TBHQ and PG were more efficient and presented synergistic effect. BHT and BHA were the least efficient, as well as their mixtures. The thermodynamic activation parameters of the reactions, evaluated by the Eyring equation and based on the theory of the activated complex (ACT), indicated no spontaneous processes (?G‡ > 0) with positive ?H‡ values and positive and negative ?S‡ values. The application of simplex centroid mixture design, using Ea as response, showed the optimised value of 174.46 kJ mol-1 for a mixture containing 33.33 and 66.67% of TBHQ and PG, respectively.

Dionisio, Borsato; Diego, Galvan; Jaqueline L., Pereira; Juliane R., Orives; Karina G., Angilelli; Rodolfo L., Coppo.

1984-19-01

243

A Viscosity Approximation Method for Finding Common Solutions of Variational Inclusions, Equilibrium Problems, and Fixed Point Problems in Hilbert Spaces  

Directory of Open Access Journals (Sweden)

Full Text Available We introduce an iterative method for finding a common element of the set of common fixed points of a countable family of nonexpansive mappings, the set of solutions of a variational inclusion with set-valued maximal monotone mapping, and inverse strongly monotone mappings and the set of solutions of an equilibrium problem in Hilbert spaces. Under suitable conditions, some strong convergence theorems for approximating this common elements are proved. The results presented in the paper improve and extend the main results of J. W. Peng et al. (2008 and many others.

Plubtieng Somyot

2009-01-01

244

Statistical Reporting with Philip’s Sextuple and Extended Sextuple: A Simple Method for Easy Communication of Findings  

Directory of Open Access Journals (Sweden)

Full Text Available The advance of science and human knowledge is impeded by misunderstandings of various statistics, insufficient reporting of findings, and the use of numerous standardized and non-standardized presentations of essentially identical information. Communication with journalists and the public is hindered by the failure to present statistics that are easy for non-scientists to interpret as well as by use of the word significant, which in scientific English does not carry the meaning of “important” or “large.” This article promotes a new standard method for reporting two-group and two-variable statistics that can enhance the presentation of relevant information, increase understanding of findings, and replace the current presentations of two-group ANOVA, t-tests, correlations, chi-squares, and z-tests of proportions. A brief call to highly restrict the publication of risk ratios, odds ratios, and relative increase in risk percentages is also made, since these statistics appear to provide no useful scientific information regarding the magnitude of findings.

Philip Tromovitch

2012-12-01

245

THE VELOCITY CENTROID PERIODICITY OF L2 PUPPIS' SiO MASER EMISSION  

Energy Technology Data Exchange (ETDEWEB)

We report the first short term velocity centroid (VC) periodicity derived from SiO maser emission. L2 Puppis, a semi-regular AGB star, was observed using the Mopra radio telescope of the Australia Telescope National Facility in the SiO v = 1, J = 1-0 and v = 1, J = 2-1 transitions. It exhibits a 139 day period in its SiO maser VC based on a period folding analysis and a Lomb Scargle analysis. L2 Pup's SiO maser emission has an unusually large velocity range and an unusual three-peaked spectrum. To create the change in VC the entire spectrum does not shift in velocity, but changes in the relative emission of the peaks generate the variation. The changes in the VC may be due to differential illumination, an asymmetric circumstellar distribution of material, or a mixture of causes. The unusual velocity structure, similar to that observed in Orion source 1, may be due to revolution of the circumstellar material or asymmetries in the circumstellar environment.

McIntosh, Gordon C. [Division of Science and Mathematics, University of Minnesota, Morris, Morris, MN 56267 (United States); Indermuehle, Balthasar [Australia Telescope National Facility, Locked Bag 194, Narrabri, NSW 2390 (Australia)

2013-09-01

246

Centroid and Envelope Eynamics of Charged Particle Beams in an Oscillating Wobbler and External Focusing Lattice for Heavy Ion Fusion Applications  

International Nuclear Information System (INIS)

Recent heavy ion fusion target studies show that it is possible to achieve ignition with direct drive and energy gain larger than 100 at 1MJ. To realize these advanced, high-gain schemes based on direct drive, it is necessary to develop a reliable beam smoothing technique to mitigate instabilities and facilitate uniform deposition on the target. The dynamics of the beam centroid can be explored as a possible beam smoothing technique to achieve a uniform illumination over a suitably chosen region of the target. The basic idea of this technique is to induce an oscillatory motion of the centroid for each transverse slice of the beam in such a way that the centroids of different slices strike different locations on the target. The centroid dynamics is controlled by a set of biased electrical plates called 'wobblers'. Using a model based on moments of the Vlasov-Maxwell equations, we show that the wobbler deflection force acts only on the centroid motion, and that the envelope dynamics are independent of the wobbler fields. If the conducting wall is far away from the beam, then the envelope dynamics and centroid dynamics are completely decoupled. This is a preferred situation for the beam wobbling technique, because the wobbler system can be designed to generate the desired centroid motion on the target without considering its effects on the envelope and emittance. A conceptual design of the wobbler system for a heavy ion fusion dr

247

Centroid and Envelope Eynamics of Charged Particle Beams in an Oscillating Wobbler and External Focusing Lattice for Heavy Ion Fusion Applications  

Energy Technology Data Exchange (ETDEWEB)

Recent heavy ion fusion target studies show that it is possible to achieve ignition with direct drive and energy gain larger than 100 at 1MJ. To realize these advanced, high-gain schemes based on direct drive, it is necessary to develop a reliable beam smoothing technique to mitigate instabilities and facilitate uniform deposition on the target. The dynamics of the beam centroid can be explored as a possible beam smoothing technique to achieve a uniform illumination over a suitably chosen region of the target. The basic idea of this technique is to induce an oscillatory motion of the centroid for each transverse slice of the beam in such a way that the centroids of different slices strike different locations on the target. The centroid dynamics is controlled by a set of biased electrical plates called 'wobblers'. Using a model based on moments of the Vlasov-Maxwell equations, we show that the wobbler deflection force acts only on the centroid motion, and that the envelope dynamics are independent of the wobbler fields. If the conducting wall is far away from the beam, then the envelope dynamics and centroid dynamics are completely decoupled. This is a preferred situation for the beam wobbling technique, because the wobbler system can be designed to generate the desired centroid motion on the target without considering its effects on the envelope and emittance. A conceptual design of the wobbler system for a heavy ion fusion driver is briefly summarized.

Ronald C. Davidson and B. Grant Logan

2011-07-19

248

Franck-Condon factors and r-centroids for certain band systems of gallium and indium mono-fluorides  

International Nuclear Information System (INIS)

For the first time, the Franck-Condon factors and r-centroids, which are very closely related to vibrational transition probabilities, have been evaluated for the bands of A3?+0 - Xl ?+, B3 ?-1 - Xl ?+, and C1? - Xl ?+ systems of Ga F and In F molecules. A numerical integration procedure is followed to evaluate these transition probability parameters, using a suitable potential. (Author)

249

Finding possible transition states of defects in silicon-carbide and alpha-iron using the dimer method  

CERN Document Server

Energetic primary recoil atoms from ion implantation or fast neutron irradiation produce isolated point defects and clusters of both vacancies and interstitials. The migration energies and mechanisms for these defects are crucial to successful multiscale modeling of microstructural evolution during ion-implantation, thermal annealing, or under irradiation over long periods of time. The dimer method is employed to search for possible transition states of interstitials and small interstitial clusters in SiC and alpha-Fe. The method uses only the first derivatives of the potential energy to find saddle points without knowledge of the final state of the transition. In SiC, the possible migration pathway for the C interstitial is found to consist of the first neighbor jump via a Si site or second neighbor jump, but the relative probability for the second neighbor jump is very low. In alpha-Fe, the possible transition states are studied as a function of interstitial cluster size, and the lowest energy barriers corr...

Gao Fei; Weber, W J; Corrales, L R; Jonsson, H

2003-01-01

250

A third study of case-finding methods for pulmonary tuberculosis in Kenya, including the use of community leaders.  

Science.gov (United States)

Five methods of identifying tuberculosis suspects were investigated in the Machakos District of Kenya by: (1) 3-monthly interrogation of the Community Elders, (2) interrogation of household heads, (3) identifying suspects amongst outpatients attending local health units, (4) examination of patients registered during the previous 10 years in the District Tuberculosis Register and also (5) their close contacts. Sputum was bacteriologically examined by smear and culture from suspects found by all the methods. The initial interrogation of the Elders yielded 216 suspects, of whom 9 were culture-positive, including 6 smear-positive. Reinterrogating the Elders 4 times at 3-monthly intervals produced a further 114 suspects including 4 culture-positive cases (3 being smear-positive). The examination of a second sputum specimen from suspects after a 3-month interval yielded 4 further culture-positive cases (all smear-negative) but the examination of a third specimen after a further 3 months yielded no further cases. A single interrogation of 1093 household head suspects yielded 22 culture-positive cases, including 11 smear-positive. The response in 5 health units covering a population of about 24 500 was poor. During a 2-year period only 109 suspects were recorded; 7 were culture-positive, including 3 smear-positive. Of 61 cases of tuberculosis registered during the previous 10 years, 8 were currently culture-positive, 5 being smear-positive. Of 318 household contacts of these cases, 6 were culture-positive cases, 2 being smear-positive. The problems presented by different active case-finding methods are discussed, identifying those that appear promising and those unpromising. PMID:7303164

Nsanzumuhire, H; Aluoch, J A; Karuga, W K; Edwards, E A; Stott, H; Fox, W; Sutherland, I

1981-06-01

251

Method for finding metabolic properties based on the general growth law. Liver examples. A general framework for biological modeling.  

Science.gov (United States)

We propose a method for finding metabolic parameters of cells, organs and whole organisms, which is based on the earlier discovered general growth law. Based on the obtained results and analysis of available biological models, we propose a general framework for modeling biological phenomena and discuss how it can be used in Virtual Liver Network project. The foundational idea of the study is that growth of cells, organs, systems and whole organisms, besides biomolecular machinery, is influenced by biophysical mechanisms acting at different scale levels. In particular, the general growth law uniquely defines distribution of nutritional resources between maintenance needs and biomass synthesis at each phase of growth and at each scale level. We exemplify the approach considering metabolic properties of growing human and dog livers and liver transplants. A procedure for verification of obtained results has been introduced too. We found that two examined dogs have high metabolic rates consuming about 0.62 and 1 gram of nutrients per cubic centimeter of liver per day, and verified this using the proposed verification procedure. We also evaluated consumption rate of nutrients in human livers, determining it to be about 0.088 gram of nutrients per cubic centimeter of liver per day for males, and about 0.098 for females. This noticeable difference can be explained by evolutionary development, which required females to have greater liver processing capacity to support pregnancy. We also found how much nutrients go to biomass synthesis and maintenance at each phase of liver and liver transplant growth. Obtained results demonstrate that the proposed approach can be used for finding metabolic characteristics of cells, organs, and whole organisms, which can further serve as important inputs and constraints for many applications in biology (such as protein expression), biotechnology (synthesis of substances), and medicine. PMID:24940740

Shestopaloff, Yuri K

2014-01-01

252

The centroid shift of the 5d levels of Ce sup 3 sup + with respect to the 4f levels in ionic crystals, a theoretical investigation  

CERN Document Server

The centroid shifts of the 5d level of Ce sup 3 sup + in BaF sub 2 , LaAlO sub 3 and LaCl sub 3 have been calculated using the ionic cluster approach. By applying configuration interaction as extension of the basic HF-LCAO approach the dynamical polarization contribution to the centroid shift was calculated. This was found to be only successful if basis sets are used optimized for polarization of the anions.

Andriessen, J; Eijk, C W E

2002-01-01

253

Franck-Condon factors and r-centroids for certain band systems of gallium and indium mono-fluorides  

Energy Technology Data Exchange (ETDEWEB)

For the first time, the Franck-Condon factors and r-centroids, which are very closely related to vibrational transition probabilities, have been evaluated for the bands of A{sup 3}{pi}{sup +}{sub 0} - X{sup l} {sigma}{sup +}, B{sup 3} {pi}{sup -}{sub 1} - X{sup l} {sigma}{sup +}, and C{sup 1}{pi} - X{sup l} {sigma}{sup +} systems of Ga F and In F molecules. A numerical integration procedure is followed to evaluate these transition probability parameters, using a suitable potential. (Author)

Prithivi Kumaran, N.; Raja, V.; Rajamanickam, N. [Physics Research Centre, V.H.N.S.N. College, Virudhunagar 626 001 (India)]. E-mail: nrvnrindia@yahoo.co.in

2003-07-01

254

Morse Franck--Condon factors and R-centroids for some Lyman bands of H2, HD, and D2  

International Nuclear Information System (INIS)

Using new rotational and vibrational constants, Morse Franck-Condon factors and r-centroids are computed for 108 Lyman bands of astrophysical importance H2, HD and D2 molecules. Experimental oscillator strengths conjoint with Morse Franck--Condon Factors for six Lyman bands of molecular hydrogen yield radiative lifetimes for v = 0 to 5 levels of the B 1SIGMA+/sub u/ state that are inconsistent with the experimental lifetime measurements. The limitation of analytic Morse function in the region of small internuclear separation for the B 1SIGMA+/sub u/ state of H2 is discussed. The r-centroids (r/sub v'v''/) are found to increase with frequencies of the Lyman bands of H2, HD and D2. For a sequence, ?r identical with r/sub v'+1,v''+1/ -- r/sub v'v''/ is constant. A comparison of r/sub v'v''/ values of the Lyman bands shows that r/sub v'v''/ of the band (v'v'') increases in going from H2 to D2

255

Constraints on the centroid moment tensors of the 2010 Maule and 2011 Tohoku earthquakes from radial modes  

Science.gov (United States)

Surface acceleration caused by the radial modes depends only on the Mrr component of the centroid moment tensor and on its depth assuming the isotropic component to be negligible. The 0S0-mode amplitude enables one to obtain a relatively narrow interval of Mrr values, whereas 1S0-mode amplitude is more sensitive to centroid depth. We have used these facts to analyze the 2010 Maule (Chile) Mw = 8.8 and 2011 Tohoku (Japan) Mw = 9.1 earthquakes using PREM. Superconducting gravimeter data available within the framework of the Global Geodynamic Project reveal that the Mrr components of these earthquakes should be in the interval 0.95-1.15 × 1022 Nm (Maule) and 1.50-1.75 × 1022 Nm (Tohoku), respectively. Re-evaluation of the modal quality factors Q is needed to obtain constraints on Mrr self-consistently. The joint analysis of gravity data from both events yields Q = 5500 ± 140 for the 0S0 mode and Q = 2000 ± 80 for the 1S0 mode. We were not able to determine the quality factor of the 2S0 mode with an accuracy sufficient to allow meaningful constraints (Q = 1120 ± 270).

Zábranová, E.; Matyska, C.; Hanyk, L.; Pálinkáš, V.

2012-09-01

256

An algebraic method for finding a series of exact solutions to integrable and nonintegrable nonlinear evolution equations  

International Nuclear Information System (INIS)

An algebraic method is devised to uniformly construct a series of exact solutions for general integrable and nonintegrable nonlinear evolution equations. Compared with most existing tanh methods, the Jacobi function expansion method or other sophisticated methods, the proposed method not only gives new and more general solutions, but also provides a guideline to classify the various types of the solutions according to the values of some parameters. The solutions obtained in this paper include (a) polynomial solutions, (b) exponential solutions, (c) rational solutions, (d) triangular periodic wave solutions, (e) hyperbolic and solitary wave solutions and (f) Jacobi and Weierstrass doubly periodic wave solutions. The efficiency of the method can be demonstrated on a large variety of nonlinear equations such as those considered in this paper, new (2 + 1)-dimensional Calogero-KdV equation, (3 + 1)-dimensional Jimbo-Miwa equation, symmetric regular long wave equation, Drinfel'd-Sokolov-Wilson equation, (2 + 1)-dimensional generalized dispersive long wave equation, double sine-Gordon equation, Calogero-Degasperis-Fokas equation and coupled Schroedinger-Boussinesq equation. In addition, the links among our proposed method, the tanh method, the extended method and the Jacobi function expansion method are also clarified generally

257

A robust spectral method for finding lumpings and meta stable states of non-reversible Markov chains  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A spectral method for identifying lumping in large Markov chains is presented. Identification of meta stable states is treated as a special case. The method is based on spectral analysis of a self-adjoint matrix that is a function of the original transition matrix. It is demonstrated that the technique is more robust than existing methods when applied to noisy non-reversible Markov chains.

Jacobi, Martin Nilsson

2008-01-01

258

Experiences of racism and discrimination among migrant care workers in England: findings from a mixed-methods research project  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Abstract This article reports part of the findings of research undertaken in 2007-09 that aimed to investigate the contribution made by migrant workers to the care workforce in England. The study involved analysis of national statistics on social care and social workers and semi-structured interviews with a wide range of stakeholders, including 96 migrant care workers. The interviews elicited some accounts relating experiences of racism and discrimination from some peo...

2011-01-01

259

Differential form method for finding symmetries of a (2 + 1)-dimensional Camassa–Holm system based on its Lax pair  

International Nuclear Information System (INIS)

In this paper, we use the differential form method to seek Lie point symmetries of a (2 + 1)-dimensional Camassa–Holm (CH) system based on its Lax pair. Then we reduce both the system and its Lax pair with the obtained symmetries, as a result some reduced (1 + 1)-dimensional equations with their new Lax pairs are presented. At last, the conservation laws for the CH system are derived from a direct method.

260

?????????????????????? A Filled Function Method of Finding Weak Efficient Mi-nimizer for Convex Multi-Objective Optimization  

Directory of Open Access Journals (Sweden)

Full Text Available ?????????????????????????????????????????????????????????????????????????????????????????To a kind of multi-objective optimization problem, which objective function is convex vector function and which constraints are box sets, firstly we use linear weighted method to turn it into nonconvex single-objective optimization problem, secondly we get the global minimizer of the single-objective optimi-zation problem by implying the filled function method, then we attain the weak efficient minimizer of the prime multi-objective optimization problem.

??

2011-07-01

 
 
 
 
261

Using quantitative and qualitative data in health services research – what happens when mixed method findings conflict? [ISRCTN61522618  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background In this methodological paper we document the interpretation of a mixed methods study and outline an approach to dealing with apparent discrepancies between qualitative and quantitative research data in a pilot study evaluating whether welfare rights advice has an impact on health and social outcomes among a population aged 60 and over. Methods Quantitative and qualitative data were collected contemporaneously. Quantitative data were collected...

Mackintosh Joan; Moffatt Suzanne

2006-01-01

262

OMERACT 10 sharp symposium: important findings in examination of imaging methods for measurement of joint damage in rheumatoid arthritis  

DEFF Research Database (Denmark)

The Sharp Symposium was held at the Outcome Measures in Rheumatology Clinical Trials 2010 meeting (OMERACT 10) in honor of the late John Sharp, consummate rheumatologist and researcher. The symposium focused on the status of current scoring methods in radiography, magnetic resonance imaging (MRI), and ultrasound (US) in rheumatoid arthritis (RA), as well as on the use of soluble and tissue biomarkers in RA, with the aim of updating recommendations regarding methods for enhanced detection, monitoring, and prediction of joint damage in clinical trials.

Strand, Vibeke; Kingsbury, Sarah R

2011-01-01

263

Optimization of a fermented soy product formulation with a kefir culture and fiber using a simplex-centroid mixture design.  

Science.gov (United States)

The objective of this work was to optimize a fermented soy product formulation with kefir and soy, oat and wheat fibers and to evaluate the fiber and product characteristics. A simplex-centroid mixture design was used for the optimization. Soymilk, soy, oat and wheat fiber mixtures, sucrose and anti-foaming agent were used for the formulation, followed by thermal treatment, cooling and the addition of flavoring. Fermentation was performed at 25?°C with a kefir culture until a pH of 4.5 was obtained. The products were cooled, homogenized and stored for analysis. From the mathematical models and variables response surface and desirability an optimal fermented product was formulated containing 3% (w/w) soy fiber. Compared with the other formulations, soy fermented product with 3% soy fiber had the best acidity, viscosity, syneresis, firmness and Lactococcus lactis count. PMID:23876105

Baú, Tahis Regina; Garcia, Sandra; Ida, Elza Iouko

2013-12-01

264

Diagnostic methods in finding out the causes of infertility, results of HSG examination and laparoscopy in infertile women examined at the Gynecological Ward of the City Hospital  

International Nuclear Information System (INIS)

The paper presents diagnostic methods and the results of hysterosalpingography (HSG) and laparoscopy examination, with special attention being drawn to the usefulness of these methods in finding out the causes of infertility. 51 patients with primary and second infertility were examined. HSG and laparoscopy make it possible to diagnose correctly the cause of infertility. They also enable adequate and early classification of patients for further diagnosis and treatment at highly specialized centers dealing with the problems of infertility. (author)

265

Direct digital method fast-acting analysis of the correlation-interferometric radio direction-finding with reconstructing of spatial analytical  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction. Nowadays radio control of radio electronic devices must be carried out in the conditions of sticky electromagnetic wicket, large prior uncertainty in relation to the parameters of radiations, and also in the conditions of the real time realization. The use and researches of direct digital methods of correlation-interferometric direction-finding is perspective direction in radio control realization for the indicated terms. Fundamentals of researches. In this paper, the direct digital method fast-acting analysis of the correlation-interferometric radio direction-finding with reconstructing of spatial analytical signal is executed. The estimation of time charges, fast-acting and relative time efficiency of method is executed. Conclusions. It is certain that analyzed direct method of direction-finding provides a spatial selection and simultaneous direction-finding of radiations which get in the pass frequencies band of simultaneous analysis with a width to one hundred ten megahertz real-time with the use of only one signal processor.

V. V. Tsyporenko

2013-04-01

266

Perturbed damped pendulum: finding periodic solutions via averaging method / Perturbações do pêndulo amortecido: encontrando soluções periódicas via método averaging  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Utilizando o modelo do pêndulo amortecido, introduzimos o método "averaging" no estudo de soluções periódicas de sistemas dinâmicos com pequenas perturbações não autónomas. Considerando perturbações do sistema do pêndulo amortecido, fornecemos condições suficientes para a existência de soluções peri [...] ódicas de pequena amplitude. O método "averaging" fornece uma ferramenta útil no estudo de sistemas dinâmicos e é acessível a estudantes de pós-graduação. Abstract in english Using the damped pendulum model we introduce the averaging method to study the periodic solutions of dynamical systems with small non-autonomous perturbation. We provide sufficient conditions for the existence of periodic solutions with small amplitude of the non-linear perturbed damped pendulum. Th [...] e averaging method provides a useful means to study dynamical systems, accessible to Master and PhD students.

Douglas D., Novaes.

2013-03-01

267

Finding more needles in the haystack: A simple and efficient method for improving high-throughput docking results.  

Science.gov (United States)

The technology underpinning high-throughput docking (HTD) has developed over the past few years to where it has become a vital tool in modern drug discovery. Although the performance of various docking algorithms is adequate, the ability to accurately and consistently rank compounds using a scoring function remains problematic. We show that by employing a simple machine learning method (naïve Bayes) it is possible to significantly overcome this deficiency. Compounds from the Available Chemical Directory (ACD), along with known active compounds, were docked into two protein targets using three software packages. In cases where HTD alone was able to show some enrichment, the application of naïve Bayes was able to improve upon the enrichment. The application of this methodology to enrich HTD results can be carried out without a priori knowledge of the activity of compounds and results in superior enrichment of known actives compared to the use of scoring methods alone. PMID:15139752

Klon, Anthony E; Glick, Meir; Thoma, Mathis; Acklin, Pierre; Davies, John W

2004-05-20

268

Use of a Novel Method to Find Substrates of Protein Kinase C Delta Identifies M2 Pyruvate Kinase  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Protein kinase C (PKC) family members have been implicated in numerous cellular processes. However, identifying the substrates of each PKC isozyme remains a challenge. Here, we describe a method using two dimensional (2-D) isoelectric focusing gel electrophoresis to identify substrates of delta PKC (?PKC) in MCF-7 breast carcinoma cells. We show that M2 pyruvate kinase is a substrate of ?PKC, and further characterize the interaction between M2 pyruvate kinase and ?PKC in MCF-7 cells by imm...

Siwko, Stefan; Mochly-rosen, Daria

2007-01-01

269

Characterization of a millefiori glass find from Aquincum by SEM-EDX and micro-PIXE methods  

Energy Technology Data Exchange (ETDEWEB)

Research has been focused on the analysis of archaeological glasses from the Roman age and medieval times. Study of ancient millefiori type glasses from the collection of Hungarian Museums has been started. A test measurement, carried out on a glass fragment supposedly part of a dish, was performed by SEM-EDX and micro-PIXE methods. Complementary analytical data were obtained for texture and composition. Results suggest that Roman and Mesopotamian techniques were used together. Our data contribute to data bases of millefiori glasses.

Uzonyi, I., E-mail: uzonyi@atomki.hu [Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4026 Debrecen, Bem ter 18/C (Hungary); Csontos, K.; Verebes, A. [Budapest History Museum, Aquincum Museum H-8211 Budapest, Zahony u. 4. (Hungary); Cserhati, C. [Department of Solid State Physics, University of Debrecen H-4032 Debrecen, Bem ter 18/B (Hungary); Csedreki, L.; Kis-Varga, M.; Kiss, A.Z. [Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4026 Debrecen, Bem ter 18/C (Hungary)

2011-10-15

270

Numerical methods for finding periodic points in discrete maps. High order islands chains and noble barriers in a toroidal magnetic configuration  

International Nuclear Information System (INIS)

We first remind usual physical and mathematical concepts involved in the dynamics of Hamiltonian systems, and namely in chaotic systems described by discrete 2D maps (representing the intersection points of toroidal magnetic lines in a poloidal plane in situations of incomplete magnetic chaos in Tokamaks). Finding the periodic points characterizing chains of magnetic islands is an essential step not only to determine the skeleton of the phase space picture, but also to determine the flux of magnetic lines across semi-permeable barriers like Cantori. We discuss here several computational methods used to determine periodic points in N dimensions, which amounts to solve a set of N nonlinear coupled equations: Newton method, minimization techniques, Laplace or steepest descend method, conjugated direction method and Fletcher-Reeves method. We have succeeded to improve this last method in an important way, without modifying its useful double-exponential convergence. This improved method has been tested and applied to finding periodic points of high order m in the 2D 'Tokamap' mapping, for values of m along rational chains of winding number n/m converging towards a noble value where a Cantorus exists. Such precise positions of periodic points have been used in the calculation of the flux across this Cantorus. (authors)

271

Numerical methods for finding periodic points in discrete maps. High order islands chains and noble barriers in a toroidal magnetic configuration  

Energy Technology Data Exchange (ETDEWEB)

We first remind usual physical and mathematical concepts involved in the dynamics of Hamiltonian systems, and namely in chaotic systems described by discrete 2D maps (representing the intersection points of toroidal magnetic lines in a poloidal plane in situations of incomplete magnetic chaos in Tokamaks). Finding the periodic points characterizing chains of magnetic islands is an essential step not only to determine the skeleton of the phase space picture, but also to determine the flux of magnetic lines across semi-permeable barriers like Cantori. We discuss here several computational methods used to determine periodic points in N dimensions, which amounts to solve a set of N nonlinear coupled equations: Newton method, minimization techniques, Laplace or steepest descend method, conjugated direction method and Fletcher-Reeves method. We have succeeded to improve this last method in an important way, without modifying its useful double-exponential convergence. This improved method has been tested and applied to finding periodic points of high order m in the 2D 'Tokamap' mapping, for values of m along rational chains of winding number n/m converging towards a noble value where a Cantorus exists. Such precise positions of periodic points have been used in the calculation of the flux across this Cantorus. (authors)

Steinbrecher, G. [Association Euratom-Nasti Romania, Dept. of Theoretical Physics, Physics Faculty, University of Craiova (Romania); Reuss, J.D.; Misguich, J.H. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee

2001-11-01

272

The application of infrared chemical imaging to the detection and enhancement of latent fingerprints: method optimization and further findings.  

Science.gov (United States)

Fourier transform infrared (FTIR) chemical imaging allows the collection of fingerprint images from backgrounds that have traditionally posed problems for conventional fingerprint detection methods. In this work, the suitability of this technique for the imaging of fingerprints on a wider range of difficult surfaces (including polymer banknotes, various types of paper, and aluminum drink cans) has been tested. For each new surface, a systematic methodology was employed to optimize settings such as spectral resolution, number of scans, and pixel aggregation in order to reduce collection time and file-size without compromising spatial resolution and the quality of the final fingerprint image. The imaging of cyanoacrylate-fumed fingerprints on polymer banknotes has been improved, with shorter collection times for larger image areas. One-month-old fingerprints on polymer banknotes have been successfully fumed and imaged. It was also found that FTIR chemical imaging gives high quality images of cyanoacrylate-fumed fingerprints on aluminum drink cans, regardless of the printed background. Although visible and UV light sources do not yield fingerprint images of the same quality on difficult, nonporous backgrounds, in many cases they can be used to locate a fingerprint prior to higher quality imaging by the FTIR technique. Attempts to acquire FTIR images of fingerprints on paper-based porous surfaces that had been treated with established reagents such as ninhydrin were all unsuccessful due to the swamping effect of the cellulose constituents of the paper. PMID:17680795

Tahtouh, Mark; Despland, Pauline; Shimmon, Ronald; Kalman, John R; Reedy, Brian J

2007-09-01

273

A new method for the discovery of the best threshold value for finding positive or negative association rules using Binary Particle Swarm Optimization  

Directory of Open Access Journals (Sweden)

Full Text Available In association rule mining most of former researches have worked on analytic optimizing method , but finding and specifying the advocate initiation limit influences on association rule mining's quality , which still is important hence this research wants to present a new algorithm for optimizing the analytic efficiency improvement including automatic analyze proper amount for initiation. Through former method this task had been performing based on positive rules but regarding that finding the negative ones were though for administrator, this research's privilege is that the initiation level automatically is analyzed for the first time; also it has high efficiency in large data base. Particle Swarm Optimization is observed for any particle's efficiency and as data turned in binary the advocate amount will be found. Results showed Particle Swarm Optimization could present better initiation level, and enhance the former algorithm's result a lot. Consequence will be comparing with Weka and Apriori.

Abdoljabbar Asadi

2012-11-01

274

Improved centroid moment tensor analyses in the NIED AQUA (Accurate and QUick Analysis system for source parameters)  

Science.gov (United States)

The rapid determination of hypocentral parameters and their transmission to the public are valuable components of disaster mitigation. We have operated an automatic system for this purpose—termed the Accurate and QUick Analysis system for source parameters (AQUA)—since 2005 (Matsumura et al., 2006). In this system, the initial hypocenter, the moment tensor (MT), and the centroid moment tensor (CMT) solutions are automatically determined and posted on the NIED Hi-net Web site (www.hinet.bosai.go.jp). This paper describes improvements made to the AQUA to overcome limitations that became apparent after the 2011 Tohoku Earthquake (05:46:17, March 11, 2011 in UTC). The improvements included the processing of NIED F-net velocity-type strong motion records, because NIED F-net broadband seismographs are saturated for great earthquakes such as the 2011 Tohoku Earthquake. These velocity-type strong motion seismographs provide unsaturated records not only for the 2011 Tohoku Earthquake, but also for recording stations located close to the epicenters of M>7 earthquakes. We used 0.005-0.020 Hz records for M>7.5 earthquakes, in contrast to the 0.01-0.05 Hz records employed in the original system. The initial hypocenters determined based on arrival times picked by using seismograms recorded by NIED Hi-net stations can have large errors in terms of magnitude and hypocenter location, especially for great earthquakes or earthquakes located far from the onland Hi-net network. The size of the 2011 Tohoku Earthquake was initially underestimated in the AQUA to be around M5 at the initial stage of rupture. Numerous aftershocks occurred at the outer rise east of the Japan trench, where a great earthquake is anticipated to occur. Hence, we modified the system to repeat the MT analyses assuming a larger size, for all earthquakes for which the magnitude was initially underestimated. We also broadened the search range of centroid depth for earthquakes located far from the onland Hi-net network. After implementing the above improvements, the CMT solution for the 2011 Tohoku Earthquake was successfully determined with a moment magnitude (Mw) of 8.6 (9.04 × 10^21 Nm). The focal mechanisms and centroid depths of the 2011 Tohoku Earthquake and M>7 aftershocks, as obtained using the improved system, are in agreement with those from the GlobalCMT. The sizes of these earthquakes are also consistent with those of GlobalCMT, with differences of less than Mw 0.1 except for the mainshock (Mw9.1, 5.31 × 10^22 Nm, GlobalCMT). This discrepancy may indicate that the bandwidth used in the analysis is insufficient for an earthquake of this size. To address this shortcoming, we used 0.0025-0.0100 Hz records and obtained a magnitude of Mw8.9 (3.35 × 10^22 Nm). This result is consistent with the GlobalCMT and other results (e.g., Mw 9.0, 3.43 × 10^22 Nm reported by Ozawa et al., 2011; Mw9.0, 4.42 × 10^22 Nm reported by Suzuki et al., 2011). Using the improved system, the CMT analysis for the 2011 Tohoku Earthquake is estimated to be completed within 12 minutes of the origin time.

Kimura, H.; Asano, Y.; Matsumoto, T.

2012-12-01

275

Image motion compensation by area correlation and centroid tracking of solar surface features  

Science.gov (United States)

An experimental solar correlation tracker was tested and evaluated on a ground-based solar magnetograph. Using sunspots as fixed targets, tracking error signals were derived by which the telescope image was stabilized against wind induced perturbations. Two methods of stabilization were investigated; mechanical stabilization of the image by controlled two-axes motion of an active optical element in the telescope beam, and electronic stabilization by biasing of the electron scan in the recording camera. Both approaches have demonstrated telescope stability of about 0.6 arc sec under random perturbations which can cause the unstabilized image to move up to 120 arc sec at frequencies up to 30 Hz.

Nein, M. E.; Mcintosh, W. R.; Cumings, N. P.

1983-01-01

276

Finding the transition state without initial guess: the growing string method for Newton trajectory to isomerization and enantiomerization reaction of alanine dipeptide and poly(15)alanine.  

Science.gov (United States)

We report a new, high-dimensional application of a method for finding a transition state (TS) between a reactant and a product on the potential energy surface: the search of a growing string along a reaction path defined by any Newton trajectory in combination with the Berny method (Quapp, J Chem Phys (2005), 122, 174106; we have provided this algorithm on a web page). Two given minima are connected by a one-dimensional, but usually curvilinear reaction coordinate. It leads to the TS region. The application of the method to alanine dipeptide finds the TS of the isomerisation C(7 ax) --> C(5), some TSs of the enantiomerisation of C(7 ax) from L-form to quasi-D-form, and it finds the TS region of a transition of a partly unfolded, bent structure which turns back into a mainly alpha-helix in the Ac(Ala)(15)NHMe polyalanine (all at the quantum mechanical level B3LYP/6-31G: the growing string calculation is interfaced with the Gaussian03 package). The formation or dissolvation of some alpha- or 3(10)-hydrogen bonds of the helix are discussed along the TS pathway, as well as the case of an enantiomer at the central residue of the helix. PMID:17342714

Quapp, Wolfgang

2007-08-01

277

Vital sign sensing method based on EMD in terahertz band  

Science.gov (United States)

Non-contact respiration and heartbeat rates detection could be applied to find survivors trapped in the disaster or the remote monitoring of the respiration and heartbeat of a patient. This study presents an improved algorithm that extracts the respiration and heartbeat rates of humans by utilizing the terahertz radar, which further lessens the effects of noise, suppresses the cross-term, and enhances the detection accuracy. A human target echo model for the terahertz radar is first presented. Combining the over-sampling method, low-pass filter, and Empirical Mode Decomposition improves the signal-to-noise ratio. The smoothed pseudo Wigner-Ville distribution time-frequency technique and the centroid of the spectrogram are used to estimate the instantaneous velocity of the target's cardiopulmonary motion. The down-sampling method is adopted to prevent serious distortion. Finally, a second time-frequency analysis is applied to the centroid curve to extract the respiration and heartbeat rates of the individual. Simulation results show that compared with the previously presented vital sign sensing method, the improved algorithm enhances the signal-to-noise ratio to 1 dB with a detection accuracy of 80%. The improved algorithm is an effective approach for the detection of respiration and heartbeat signal in a complicated environment.

Xu, Zhengwu; Liu, Tong

2014-12-01

278

Low-frequency centroid-moment-tensor inversion from superconducting-gravimeter data: The effect of seismic attenuation  

Science.gov (United States)

After the 2010 Maule and 2011 Tohoku earthquakes the spheroidal modes up to 1 mHz were clearly registered by the Global Geodynamic Project (GGP) network of superconducting gravimeters (SG). Fundamental parameters in synthetic calculations of the signals are the quality factors of the modes. We study the role of their uncertainties in the centroid-moment-tensor (CMT) inversions. First, we have inverted the SG data from selected GGP stations to jointly determine the quality factors of these normal modes and the three low-frequency CMT components, Mrr,(M??-M??)/2 and M??, that generate the observed SG signal. We have used several-days-long records to minimize the trade-off between the quality factors and the CMT but it was not eliminated completely. We have also inverted each record separately to get error estimates of the obtained parameters. Consequently, we have employed the GGP records of 60-h lengths for several published modal-quality-factor sets and inverted only the same three CMT components. The obtained CMT tensors are close to the solution from the joint Q-CMT inversion of longer records and resulting variability of the CMT components is smaller than differences among routine agency solutions. Reliable low-frequency CMT components can thus be obtained for any quality factors from the studied sets.

Zábranová, Eliška; Matyska, Ctirad

2014-10-01

279

Global pathways to men's caregiving: mixed methods findings from the International Men and Gender Equality Survey and the Men Who Care study.  

Science.gov (United States)

Promoting men's participation in unpaid care work is part of the Programme of Action for the International Conference on Population and Development. However, men's involvement in care work does not mirror the advances women have made in paid work outside the home. This mixed method study explores which men are more involved in caregiving, and what childhood and adulthood factors influence their level of involvement. Quantitative research presents findings from 1169 men across six countries with children aged 0-4, and a qualitative study presents findings from in-depth interviews with 83 men engaged in atypical caregiving practices. Survey research finds that being taught to care for children, witnessing one's father take care of one's siblings, respondents' present attitudes about gender equality and having outside help (or none, in some cases) were all also associated with men's higher level of involvement. Qualitative research reveals that men's experiences of violence, the normalisation of domestic work as children and life circumstances rather than greater-than-average beliefs in gender equality all propelled them into care work. Findings suggest that engaging more men into care work implies changes to policies and structural realities in the workplace coupled with changing gender attitudes. These insights inform policy and practice aimed at promoting greater involvement in care work by men. PMID:24938308

Kato-Wallace, Jane; Barker, Gary; Eads, Marci; Levtov, Ruti

2014-01-01

280

A comparison of three clustering methods for finding subgroups in MRI, SMS or clinical data : SPSS TwoStep Cluster analysis, Latent Gold and SNOB  

DEFF Research Database (Denmark)

BACKGROUND: There are various methodological approaches to identifying clinically important subgroups and one method is to identify clusters of characteristics that differentiate people in cross-sectional and/or longitudinal data using Cluster Analysis (CA) or Latent Class Analysis (LCA). There is a scarcity of head-to-head comparisons that can inform the choice of which clustering method might be suitable for particular clinical datasets and research questions. Therefore, the aim of this study was to perform a head-to-head comparison of three commonly available methods (SPSS TwoStep CA, Latent Gold LCA and SNOB LCA). METHODS: The performance of these three methods was compared: (i) quantitatively using the number of subgroups detected, the classification probability of individuals into subgroups, the reproducibility of results, and (ii) qualitatively using subjective judgments about each program's ease of use and interpretability of the presentation of results.We analysed five real datasets of varying complexity in a secondary analysis of data from other research projects. Three datasets contained only MRI findings (n = 2,060 to 20,810 vertebral disc levels), one dataset contained only pain intensity data collected for 52 weeks by text (SMS) messaging (n = 1,121 people), and the last dataset contained a range of clinical variables measured in low back pain patients (n = 543 people). Four artificial datasets (n = 1,000 each) containing subgroups of varying complexity were also analysed testing the ability of these clustering methods to detect subgroups and correctly classify individuals when subgroup membership was known. RESULTS: The results from the real clinical datasets indicated that the number of subgroups detected varied, the certainty of classifying individuals into those subgroups varied, the findings had perfect reproducibility, some programs were easier to use and the interpretability of the presentation of their findings also varied. The results from the artificial datasets indicated that all three clustering methods showed a near-perfect ability to detect known subgroups and correctly classify individuals into those subgroups. CONCLUSIONS: Our subjective judgement was that Latent Gold offered the best balance of sensitivity to subgroups, ease of use and presentation of results with these datasets but we recognise that different clustering methods may suit other types of data and clinical research questions.

Kent, Peter; Jensen, Rikke K

2014-01-01

 
 
 
 
281

A colorimetric method for highly sensitive and accurate detection of iodide by finding the critical color in a color change process using silver triangular nanoplates  

International Nuclear Information System (INIS)

Graphical abstract: -- Highlights: •Demonstrated a new colorimetric strategy for iodide detection by silver nanoplates. •The colorimetric strategy is to find the critical color in a color change process. •The colorimetric strategy is more accurate and sensitive than common colorimetry. •Discovered a new morphological transformation phenomenon of silver nanoplates. -- Abstract: In this contribution, we demonstrated a novel colorimetric method for highly sensitive and accurate detection of iodide using citrate-stabilized silver triangular nanoplates (silver TNPs). Very lower concentration of iodide can induce an appreciable color change of silver TNPs solution from blue to yellow by fusing of silver TNPs to nanoparticles, as confirmed by UV–vis absorption spectroscopy and transmission electron microscopy (TEM). The principle of this colorimetric assay is not an ordinary colorimetry, but a new colorimetric strategy by finding the critical color in a color change process. With this strategy, 0.1 ?M of iodide can be recognized within 30 min by naked-eyes observation, and lower concentration of iodide down to 8.8 nM can be detected using a spectrophotometer. Furthermore, this high sensitive colorimetric assay has good accuracy, stability and reproducibility comparing with other ordinary colorimetry. We believe this new colorimetric method will open up a fresh insight of simple, rapid and reliable detection of iodide and can find its future application in the biochemical analysis or clinical diagnosis

282

A colorimetric method for highly sensitive and accurate detection of iodide by finding the critical color in a color change process using silver triangular nanoplates  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: -- Highlights: •Demonstrated a new colorimetric strategy for iodide detection by silver nanoplates. •The colorimetric strategy is to find the critical color in a color change process. •The colorimetric strategy is more accurate and sensitive than common colorimetry. •Discovered a new morphological transformation phenomenon of silver nanoplates. -- Abstract: In this contribution, we demonstrated a novel colorimetric method for highly sensitive and accurate detection of iodide using citrate-stabilized silver triangular nanoplates (silver TNPs). Very lower concentration of iodide can induce an appreciable color change of silver TNPs solution from blue to yellow by fusing of silver TNPs to nanoparticles, as confirmed by UV–vis absorption spectroscopy and transmission electron microscopy (TEM). The principle of this colorimetric assay is not an ordinary colorimetry, but a new colorimetric strategy by finding the critical color in a color change process. With this strategy, 0.1 ?M of iodide can be recognized within 30 min by naked-eyes observation, and lower concentration of iodide down to 8.8 nM can be detected using a spectrophotometer. Furthermore, this high sensitive colorimetric assay has good accuracy, stability and reproducibility comparing with other ordinary colorimetry. We believe this new colorimetric method will open up a fresh insight of simple, rapid and reliable detection of iodide and can find its future application in the biochemical analysis or clinical diagnosis.

Yang, Xiu-Hua; Ling, Jian, E-mail: lingjian@ynu.edu.cn; Peng, Jun; Cao, Qiu-E., E-mail: qecao@ynu.edu.cn; Ding, Zhong-Tao; Bian, Long-Chun

2013-10-10

283

The New Multi-HAzard and MulTi-RIsK Assessment MethodS for Europe (MATRIX) Project - An overview of its major findings  

Science.gov (United States)

Recent major natural disasters, such as the 2011 T?hoku earthquake, tsunami and subsequent Fukushima nuclear accident, have raised awareness of the frequent and potentially far-reaching interconnections between natural hazards. Such interactions occur at the hazard level, where an initial hazard may trigger other events (e.g., an earthquake triggering a tsunami) or several events may occur concurrently (or nearly so), e.g., severe weather around the same time as an earthquake. Interactions also occur at the vulnerability level, where the initial event may make the affected community more susceptible to the negative consequences of another event (e.g., an earthquake weakens buildings, which are then damaged further by windstorms). There is also a temporal element involved, where changes in exposure may alter the total risk to a given area. In short, there is the likelihood that the total risk estimated when considering multiple hazard and risks and their interactions is greater than the sum of their individual parts. It is with these issues in mind that the European Commission, under their FP7 program, supported the New Multi-HAzard and MulTi-RIsK Assessment MethodS for Europe or MATRIX project (10.2010 to 12.2013). MATRIX set out to tackle multiple natural hazards (i.e., those of concern to Europe, namely earthquakes, landslides, volcanos, tsunamis, wild fires, storms and fluvial and coastal flooding) and risks within a common theoretical framework. The MATRIX work plan proceeded from an assessment of single-type risk methodologies (including how uncertainties should be treated), cascade effects within a multi-hazard environment, time-dependent vulnerability, decision making and support for multi-hazard mitigation and adaption, and an assessment of how the multi-hazard and risk viewpoint may be integrated into current decision making and risk mitigation programs, considering the existing single-hazard and risk focus. Three test sites were considered during the project: Naples, Cologne, and the French West Indies. In addition, a software platform, the MATRIX-Common IT sYstem (MATRIX-CITY), was developed to allow the evaluation of characteristic multi-hazard and risk scenarios in comparison to single-type analyses. This presentation therefore outlines the more significant outcomes of the project, in particular those dealing with the harmonization of single-type hazards, cascade event analysis, time-dependent vulnerability changes and the response of the disaster management community to the MATRIX point of view.

Fleming, Kevin; Zschau, Jochen; Gasparini, Paolo

2014-05-01

284

Reliability of change in lumbar MRI findings over time in patients with and without disc prosthesis - comparing two different image evaluation methods  

Energy Technology Data Exchange (ETDEWEB)

To assess the reliability of change in lumbar magnetic resonance imaging (MRI) findings evaluated retrospectively by direct comparison of images and by non-comparison. Pre-treatment and 2-year follow-up MRI was performed in 126 patients randomized to disc prosthesis surgery or non-surgical treatment. Two experienced radiologists independently evaluated progress and regress for Modic changes, disc findings, and facet arthropathy (FA) at L3/L4, L4/L5, and L5/S1, both by non-comparison and by comparison of initial and follow-up images. FA was evaluated at all levels, and other findings at non-operated levels. We calculated prevalence- and bias-adjusted kappa (PABAK) values for interobserver agreement. The impact of an adjacent prosthesis (which causes artefacts) and image evaluation method on PABAK was assessed using generalized estimating equations. Image comparison indicated good interobserver agreement on progress and regress (PABAK 0.63-1.00) for Modic changes, posterior high-intensity zone, disc height, and disc contour at L3-S1 and for nucleus pulposus signal and FA at L3/L4; and moderate interobserver agreement (PABAK 0.46-0.59) on decreasing nucleus signal and increasing FA at L4-S1. Image comparison indicated lower (but fair) interobserver agreement (PABAK 0.29) only for increasing FA at L5/S1 in patients with prosthesis in L4/L5 and/or L5/S1. An adjacent prosthesis had no overall impact on PABAK values (p {>=} 0.22). Comparison yielded higher PABAK values than non-comparison (p < 0.001). Regarding changes in lumbar MRI findings over time, comparison of images can provide moderate or good interobserver agreement, and better agreement than non-comparison. An adjacent prosthesis may not reduce agreement on change for most findings. (orig.)

Berg, Linda; Espeland, Ansgar [Haukeland University Hospital, Department of Radiology, Bergen (Norway); University of Bergen, Section for Radiology, Department of Surgical Sciences, Bergen (Norway); Gjertsen, Oeivind [Oslo University Hospital, Department of Neuroradiology, Oslo (Norway); Hellum, Christian [Oslo University Hospital, Department of Orthopaedics, Oslo (Norway); University of Oslo, Department of Orthopaedics, Oslo (Norway); Neckelmann, Gesche [Haukeland University Hospital, Department of Radiology, Bergen (Norway); Johnsen, Lars G. [University Hospital of Trondheim, National Centre for Diseases of the Spine, Trondheim (Norway); University Hospital of Trondheim, Orthopaedic Department, Trondheim (Norway); Eide, Geir E. [Haukeland University Hospital, Centre for Clinical Research, Bergen (Norway); University of Bergen, Department of Public Health and Primary Health Care, Bergen (Norway)

2012-12-15

285

Method of transient identification based on a possibilistic approach, optimized by genetic algorithm  

International Nuclear Information System (INIS)

This work develops a method for transient identification based on a possible approach, optimized by Genetic Algorithm to optimize the number of the centroids of the classes that represent the transients. The basic idea of the proposed method is to optimize the partition of the search space, generating subsets in the classes within a partition, defined as subclasses, whose centroids are able to distinguish the classes with the maximum correct classifications. The interpretation of the subclasses as fuzzy sets and the possible approach provided a heuristic to establish influence zones of the centroids, allowing to achieve the 'don't know' answer for unknown transients, that is, outside the training set. (author)

286

Fossil Find  

Science.gov (United States)

In this classroom activity, middle school students simulate a "dinosaur dig." The activity opens with background information for teachers about fossils. Working in groups, students excavate fossil sites created in advance by the teacher, or other group of students, and try to reconstruct a chicken skeleton. The activity closes with a two-page student worksheet that directs students to diagram the fossil site and includes probing questions to help them decode their findings.

287

Finding Colors  

Science.gov (United States)

In this chemistry challenge, learners combine acids and bases in a universal indicator to create five different colors. Using vinegar, washing soda, and Bogen universal indicator, the goal is to find combinations that create red, orange, yellow, green, and blue solutions. Background information explains a little about how acids and bases interact to affect the pH of a solution, and how the indicator changes color based on the pH. Safety notes are included.

Sciencenter

2014-08-27

288

Optimal Centroid Position Estimation  

Energy Technology Data Exchange (ETDEWEB)

The alignment of high energy laser beams for potential fusion experiments demand high precision and accuracy by the underlying positioning algorithms. This paper discusses the feasibility of employing online optimal position estimators in the form of model-based processors to achieve the desired results. Here we discuss the modeling, development, implementation and processing of model-based processors applied to both simulated and actual beam line data.

Candy, J V; McClay, W A; Awwal, A S; Ferguson, S W

2004-07-23

289

Charge Transfer Efficiency of the STIS CCD:The time dependence of charge loss and centroid shiftsfrom Internal Sparse Field data  

Science.gov (United States)

We describe the Internal Sparse Field test used to characterize relevant aspects of the decreasing Charge TransferEf ciency (CTE) of the STIS CCD with elapsed on-orbit time. We measure two main observational effectsof CTE: Fractional signal loss and centroid shift, using arti cial point-source spectra read out by ampli ersat both serial registers. We derive time constants of the increases of fractional signal loss (21.8% yr-1) and centroid shift (16.0% yr-1) due to CTE effects, and a very tight relation between the two. This relationshould be useful for science programs requiring sub-pixel astrometric accuracy. Finally, we compare results inthe two supported gain settings of the STIS CCD (gain=1 and gain= 4).

Goudfrooij, Paul; Maíz Apellániz, Jesús; Brown, Tom; Kimble, Randy

2006-02-01

290

New treatment method for developmental dysplasia of the hips after walking age. Arthroscopic reduction with limboplasty based on the findings of preoperative imaging  

International Nuclear Information System (INIS)

What makes treatment choice for developmental dysplasia of the hips diagnosed after walking age difficult is the poor understanding of prereduction conditions that obstruct the reduction in spatial terms. To evaluate these problems, we employed subtraction three-dimensional imaging to search for the factors involved in intraarticular obstruction. On the basis of the findings of preoperative subtraction three-dimensional imaging from computed tomography, we developed a new method, a minimum invasive arthroscopic reduction with limboplasty, for reduction of developmental dysplasia of the hips after walking age. The purposes of this report were to: describe the technique of the arthroscopic procedure, and evaluate our new method using radiographic parameters. Ten patients with ten hips with developmental dysplasia after walking age treated by arthroscopic reduction with limboplasty were included in this study. The mean age of the patients at reduction was 22.6 months (range, 18.6-29.7 months); mean age at follow up was 7.2 years (range, 3.9-10.9 years); and mean follow up was 5.4 years (range, 1.7-9.0 years). These ten hips were evaluated using radiographic measurements. Moderate or severe avascular necrosis of the femoral head was not observed. Two hips that had a spherical-shaped head with minimal residual height loss or coxa magna were classified as Kalamchi and MacEwen grade 1. Additional surgery had been performed for two hips classified as Severin group 4 during thps classified as Severin group 4 during the course of follow up. These two hips were classified as Severin group 1 at final examination. One more hip was classified as Severin group 4 at final examination, and additional surgery was recommended. The remaining seven hips (70%) therefore obtained good evaluations by arthroscopic reduction with limboplasty alone. We developed a new reduction method by using an arthroscopic procedure for the reduction of developmental dysplasia of the hips after walking age when this dysplasia failed to be reduced with nonoperative methods. The result of our new method is acceptable because good evaluations were obtained in 70% of hips 5.4 years after reduction by our new method alone. (author)

291

Ce{sup 3+} 5d-centroid shift and vacuum referred 4f-electron binding energies of all lanthanide impurities in 150 different compounds  

Energy Technology Data Exchange (ETDEWEB)

A review on the wavelengths of all five 4f-5d transitions for Ce{sup 3+} in about 150 different inorganic compounds (fluorides, chlorides, bromides, iodides, oxides, sulfides, selenides, nitrides) is presented. It provides data on the centroid shift and the crystal field splitting of the 5d-configuration which are then used to estimate the Eu{sup 2+} inter 4f-electron Coulomb repulsion energy U(6,A) in compound A. The four semi-empirical models (the redshift model, the centroid shift model, the charge transfer model, and the chemical shift model) on lanthanide levels that were developed past 12 years are briefly reviewed. It will be demonstrated how those models together with the collected data of this work and elsewhere can be united to construct schemes that contain the binding energy of electrons in the 4f and 5d states for each divalent and each trivalent lanthanide ion relative to the vacuum energy. As example the vacuum referred binding energy schemes for LaF{sub 3} and La{sub 2}O{sub 3} will be constructed. - Highlights: Black-Right-Pointing-Pointer An compilation on all five Ce{sup 3+} 4f-5d energies in 150 inorganic compounds is presented. Black-Right-Pointing-Pointer The relationship between the 5d centroid shift and host cation electronegativity id demonstrated. Black-Right-Pointing-Pointer The electronic structure scheme of the lanthanides in La{sub 2}O{sub 3} and LaF{sub 3} is presented.

Dorenbos, Pieter, E-mail: P.Dorenbos@tudelft.nl [Luminescence Materials Research group, Department of RRR, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)

2013-03-15

292

The impact of the in-orbit background and the X-ray source intensity on the centroiding accuracy of the Swift X-ray telescope  

CERN Document Server

The optical components of the Swift Gamma Ray Burst Explorer X-ray Telescope (XRT), consisting of the JET-X spare flight mirror and a charge coupled device of the type used in the EPIC program, were used in a re-calibration study carried out at the Panter facility, which is part of the Max Planck Institute for Extraterrestrial Physics. The objective of this study was to check the focal length and the off axis performance of the mirrors and to show that the half energy width (HEW) of the on-axis point spread function (PSF) was of the order of 16 arcsec at 1.5 keV (Nucl. Instr. and Meth. A 488 (2002) 543; SPIE 4140 (2000) 64) and that a centroiding accuracy better that 1 arcsec could be achieved within the 4 arcmin sampling area designated by the Burst Alert Telescope (Nucl. Instr. and Meth. A 488 (2002) 543). The centroiding accuracy of the Swift XRT's optical components was tested as a function of distance from the focus and off axis position of the PSF (Nucl. Instr. and Meth. A 488 (2002) 543). The presence ...

Ambrosi, R M; Hill, J; Cheruvu, C; Abbey, A F; Short, A D T

2002-01-01

293

Combined radioimmunoassay of 17-alpha-hydroxyprogesterone and 11-desoxycortisol, and of dehydroepiandrosterone-sulphate: Methods and some novel clinical findings  

International Nuclear Information System (INIS)

The radioimmunoassay (RIA) methods for determining 17-alpha-hydroxyprogesterone (17HOP), 11-desoxycortisol (Cpd.-S), and dehydroepiandrosterone-sulphate, are reported. The plasma levels of these hormones were measured in a series of 15 diagnostic groups including adrenal diseases, fertility-related problems and human growth hormone (HGH) deficiency states. The relations of DHEA-S and growth hormone were studied in a group of children with growth retardation who presented an absent response to HGH stimulation tests. The DHEA-S level found in these patients was significantly lower than that of their age-matched controls. Furthermore, in an etiologically different entity, i.e. head-injury patients, similar findings were also made. In a single case with HGH deficiency due to antibodies against HGH, DHEA-S levels were not detectable. It is suggested that the determination of DHEA-S plasma levels can provide further insight into the classification of patients with fertility-related problems. Furthermore, it appears that DHEA-S can be taken as an indicator for the availability of bioactive human growth hormone. The various forms of congenital adrenal hyperplasia (CAH) can be successfully screened and detected by the determination of the plasma levels of 17-alpha-hydroxyprogesterone (17HOP), of 11-desoxycortisol (Cpd.-S), and of dehydroepiandrosterone-sulphate (DHEA-S). These tests are also relevant in the investigation of patients with hirsutism, hyperandrogenism, and amenorth hirsutism, hyperandrogenism, and amenorrhea. RIA procedures for the measurement of these hormones are described and new clinical data on DHEA-S are presented in relation to fertility problems both in men and women, such as oligozoospermia, oligomenorrhea and aspermia and, in cases of human growth hormone (HGH), deficiency states such as retarded growth, head-injury patients and, in one case, HGH deficiency due to antibodies directed against HGH. The relations between normo- and hyperprolactinaemia and DHEA-S are also examined

294

MRI finding of hemangioblastomas  

International Nuclear Information System (INIS)

mages, all mural nodules were intensely enhanced. MRI provide to be a good diagnostic method to detect and characterize posterior fossa hemangioblastoma. The most common finding is Cystic posterior fossa lesion with enhancing mural nodule. Contrast enhancement is essential for specific diagnosis

295

Find far fish fast  

Science.gov (United States)

Science author Nicholas Makris from the Massachusetts Institute of Technology helped to create the new fish finding tool. He says that the fish finder will help scientists better understand how fish behave. It will also let scientists calculate the number of fish in different parts of the ocean â a task that is incredibly difficult using current methods for fish counting.

American Association for the Advancement of Science (AAAS;)

2006-02-02

296

Finding seed points for organ segmentation using example annotations  

Science.gov (United States)

Organ segmentation is important in diagnostic medicine to make current decision-support tools more effective and efficient. Performing it automatically can save time and labor. In this paper, a method to perform automatic identification of seed points for the segmentation of organs in three-dimensional (3D) non-annotated, full- body magnetic resonance (MR) and computed tomography (CT) volumes is presented. It uses 3D MR and CT acquisitions along with corresponding organ annotations from the Visual Concept Extraction Challenge in Radiology (VISCERAL) banchmark. A training MR or CT volume is first registered affinely with a carefully-chosen reference volume. The registration transform obtained is then used to warp the annotations accompanying that training volume. The process is repeated for several other training volumes. For each organ of interest, an overlap volume is created by merging the warped training annotations corresponding to it. Next, a 3D probability map for organ location on the reference volume is derived from each overlap volume. The centroid of each probability map is determined and it represents a suitable seed point for segmentation of each organ. Afterwards, the reference volume can be affinely mapped onto any non-annotated volume and the mapping applied to the pre-computed volume containing the centroid and the probability distribution for an organ of interest. Segmentation on the non-annotated volume may then be started using existing region-growing segmentation algorithms with the warped centroid as the seed point and the warped probability distribution as an aid to the stopping criterion. The approach yields very promising results.

Joyseeree, Ranveer; Müller, Henning

2014-03-01

297

Hpm and Vim Methods for Finding the Exact Solutions of the Nonlinear Dispersive Equations and Seventh-Order Sawada-Kotera Equation  

Science.gov (United States)

In this paper, nonlinear dispersive equations and seventh-order Sawada-Kotera equation are solved using homotopy perturbation method (HPM) and variational iteration method (VIM). The results obtained by the proposed methods are then compared with that of Adomian decomposition method (ADM). The comparisons demonstrate that the two obtained solutions are in excellent agreement. The numerical results calculated show that the methods can be accurately implemented to these types of nonlinear equations. The results of HPM and VIM confirm the correctness of those obtained by Adomian decomposition method.

Ganji, D. D.; Jamshidi, N.; Ganji, Z. Z.

298

Method of particle trajectory recognition in particle flows of high particle concentration using a candidate trajectory tree process with variable search areas  

Science.gov (United States)

The application relates to particle trajectory recognition from a Centroid Population comprised of Centroids having an (x, y, t) or (x, y, f) coordinate. The method is applicable to visualization and measurement of particle flow fields of high particle. In one embodiment, the centroids are generated from particle images recorded on camera frames. The application encompasses digital computer systems and distribution mediums implementing the method disclosed and is particularly applicable to recognizing trajectories of particles in particle flows of high particle concentration. The method accomplishes trajectory recognition by forming Candidate Trajectory Trees and repeated searches at varying Search Velocities, such that initial search areas are set to a minimum size in order to recognize only the slowest, least accelerating particles which produce higher local concentrations. When a trajectory is recognized, the centroids in that trajectory are removed from consideration in future searches.

Shaffer, Franklin D.

2013-03-12

299

Methods of Pest Control and Direct Yield Loss Assessment of Country Bean (Dolichos lablab) at Farmer`s Field Condition: A Survey Finding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A survey on farmer`s pest control methods and direct yield loss assessment of country bean (Dolichos lablab) was done during September 2000 to February 2001 in North Edilpur and South Mohadebpur villages of Sitakundu under Chittagong district. Results revealed that farmers used Fanfan, Nogos, Ripcord, Malathion, Roxion and Sumithion as chemical methods and applying ash and handpicking of insect pests as non-chemical method to control insect pests. The frequency of insecticide applicati...

Ahmed, K. U.; Rahman, M. M.; Alam, M. Z.; Ahmed, S. U.

2004-01-01

300

Finding Cyclic Frequent Itemsets  

Directory of Open Access Journals (Sweden)

Full Text Available Mining various types of association rules from supermarket datasets is an important data mining problem. One similar problem involves finding frequent itemsets and then deriving rules from frequent itemsets. The supermarket data is temporal. Considering time attributes in the supermarket dataset some association rules can be extracted which may hold for a small time interval and not throughout the data gathering period. Such rules are called as local association rules and corresponding frequent itemsets as locally frequent itemsets. Mahanta et al proposes an algorithm for extracting all locally frequent itemsets where each locally frequent itemset is associated with sequence time intervals in which it is frequent. The sequence of time intervals associated with a locally frequent itemsets may exhibit some interesting properties e.g. the itemsets may be cyclic in nature. In this paper we propose an alternative method of finding such cyclic frequent itemsets. The efficacy of the method is established through experimental results.

Mazarbhuiya, F. A.

2012-11-01

 
 
 
 
301

The Use of Qualitative Methods in Large-Scale Evaluation: Improving the Quality of the Evaluation and the Meaningfulness of the Findings  

Science.gov (United States)

In light of the current debate over the meaning of "scientifically based research", we argue that qualitative methods should be an essential part of large-scale program evaluations if program effectiveness is to be determined and understood. This article chronicles the challenges involved in incorporating qualitative methods into the large-scale…

Slayton, Julie; Llosa, Lorena

2005-01-01

302

Radiological findings after gastrectomy  

International Nuclear Information System (INIS)

In 63 patients after total gastrectomy and reconstruction of the small bowel described by Beal-Longmire, Roux and Tomoda radiological findings were correlated with clinical symptoms. No correlation could be found between clinical symptoms if dumping and oesophagitis caused by reflux on one side and increased length of intestinal transit time, increased diameter of intestinal loops and gastro-oesophageal reflux on the other side. Enlarged blind loops after termino-lateral oesophago-jejunostomy and insufficient ligations (operation technique by Tomoda) were correlated with higher incidence of pains. Patients operated by the method of Beal-Longmire and Roux showed better results than those operated with the method of Tomoda. (orig.)

303

Finding important anharmonic terms in the sixth-order potential energy function by the scaled hypersphere search method: An application to vibrational analyses of molecules and clusters  

Science.gov (United States)

A fitting method of the sixth-order potential energy function is proposed, where ab initio potential energy data for the fitting are sampled in directions containing maximal anharmonic downward distortions detected by the scaled hypersphere search (SHS) method. This technique has been applied to H2O, HCHO, HCOOH, C2H4, CH3OH, CH3CHO, CH3NH2, B2H6, (H2O)2, and (H2O)3, where, without using the symmetry, 176, 904, 1432, 2992, 2520, 2760, 3608, 6232, 768, and 1456 times single-point energy calculations, respectively, were required for obtaining anharmonic terms. Experimental IR peak positions of not only fundamentals but also overtones and combinations in the excitation energy range of 1000-4000 cm-1 could be reproduced very accurately by the post-vibrational self-consistent field theory employing potential functions obtained by the present SHS based polynomial fitting method.

Maeda, Satoshi; Watanabe, Yu; Ohno, Koichi

2008-04-01

304

Granulomatous mastitis: radiological findings  

Energy Technology Data Exchange (ETDEWEB)

Purpose: To evaluate the radiological, ultrasonographic, and magnetic resonance imaging (MRI) findings of idiopathic granulomatous mastitis. Material and Methods: Between April 2002 and June 2005, the mammography, ultrasound, color Doppler ultrasound, non enhanced MR, and dynamic MR findings of nine patients with the preliminary clinical diagnosis of malignancy and the final diagnosis of granulomatous mastitis were evaluated. Results: On mammography, asymmetrical focal densities with no distinct margins, ill-defined masses with spiculated contours, and bilateral multiple ill-defined nodules were seen. On ultrasound, in four patients a discrete, heterogenous hypoechoic mass, in two patients multiple abscesses, in one patient bilateral multiple central hypo peripheral hyperechoic lesions, in two patients heterogeneous hypo- and hyperechoic areas together with parenchymal distortion, and in one patient irregular hypoechoic masses with tubular extensions and abscess cavities were seen. Five of the lesions were vascular on color Doppler ultrasound. On MR mammography, the most frequent finding was focal or diffuse asymmetrical signal intensity changes that were hypointense on T1W images and hyperintense on T2W images, without significant mass effect. Nodular lesions were also seen. On dynamic contrast-enhanced mammography, mass-like enhancement, ring-like enhancement, and nodular enhancement were seen. The time-intensity curves differed from patient to patient and from lesion to lesion. Conclusion: The imaging findings of idiopathic granulomatous mastitis have a wide spectrum, and they are inconclusive for differentiating malignant and benign lesions.

Ozturk, M.; Mavili, E.; Kahriman, G.; Akcan, A.C.; Ozturk, F. [Depts. of Radiology, Surgery, and Pathology, Erciyes Univ. Medical Faculty, Kayseri (Turkey)

2007-02-15

305

Granulomatous mastitis: radiological findings  

International Nuclear Information System (INIS)

Purpose: To evaluate the radiological, ultrasonographic, and magnetic resonance imaging (MRI) findings of idiopathic granulomatous mastitis. Material and Methods: Between April 2002 and June 2005, the mammography, ultrasound, color Doppler ultrasound, non enhanced MR, and dynamic MR findings of nine patients with the preliminary clinical diagnosis of malignancy and the final diagnosis of granulomatous mastitis were evaluated. Results: On mammography, asymmetrical focal densities with no distinct margins, ill-defined masses with spiculated contours, and bilateral multiple ill-defined nodules were seen. On ultrasound, in four patients a discrete, heterogenous hypoechoic mass, in two patients multiple abscesses, in one patient bilateral multiple central hypo peripheral hyperechoic lesions, in two patients heterogeneous hypo- and hyperechoic areas together with parenchymal distortion, and in one patient irregular hypoechoic masses with tubular extensions and abscess cavities were seen. Five of the lesions were vascular on color Doppler ultrasound. On MR mammography, the most frequent finding was focal or diffuse asymmetrical signal intensity changes that were hypointense on T1W images and hyperintense on T2W images, without significant mass effect. Nodular lesions were also seen. On dynamic contrast-enhanced mammography, mass-like enhancement, ring-like enhancement, and nodular enhancement were seen. The time-intensity curves differed from patient to patient and from lesiered from patient to patient and from lesion to lesion. Conclusion: The imaging findings of idiopathic granulomatous mastitis have a wide spectrum, and they are inconclusive for differentiating malignant and benign lesions

306

Logic and intuitive methods of management systems study during direction finding of companies’ modernization development in health resort and tourism sphere  

Directory of Open Access Journals (Sweden)

Full Text Available The article analyses existing approaches to companies’ management systems in health resort and tourism sphere, gives general characteristic of fundamental updating companies, representing some scheme of companies description according to certain set of characteristics, including those from cited logic and intuitive methods.

Alexander S. Varyukhin

2011-02-01

307

Tarsal coalitions: CT findings  

International Nuclear Information System (INIS)

Purpose: To show the CT findings and the accuracy in determining the presence of osseous or figrocartilaginous tarsal coalitions. Materials and Methods: Ten CT scans performed between 5/00 and 6/01 with the diagnosis of tarsal coalitions were evaluated. The CT scans were done with a helical scanner and a multislice one, with 1 mm collimation thickness and were evaluated in the axial, coronal and sagittal plane with MPR reconstructions. Results: We identified 6 osseous coalitions, 2 cuboid-first cuneiform and 4 talocalcaneal ones and 10 fibrocartilaginous coalitions, 4 talocalcaneal and 6 calcaneonavicular ones. Conclusion: CT determines the presence of osseous bridges or the degenerative or bone deformities associated to the diagnosis of fibrocartilaginous coalitions. In complex cases, the use of MPR reconstructions helps to find the ideal plane to establish the diagnosis. Talocalcaneal coalition is best diagnosed by coronal MPR reconstruction. (author)

308

Selected imaging methods to assess treatment results in ovarian cancer - ultrasound examination and computed tomography versus '' second-look '' laparotomy findings  

International Nuclear Information System (INIS)

s there was no statistically significant difference between combined imaging results and CT alone for any anatomic location but combined CT/US results for the whole abdomen and pelvis were more accurate than the results of each modality performed separately - achieving statistical significance. US and CT performed before '' second-look '' laparotomy have high accuracy, which renders them important elements of the ovarian cancer treatment strategy. None of the evaluated methods appeared superior over the other when used separately although the CT results appeared slightly more accurate. A combination of both methods allows obtaining more accurate results than diagnostics based only on one of them. Nevertheless, it is impossible to eliminate '' second-look '' laparotomy from the procedures controlling the results of the ovarian cancer treatment due to the possibility of false negative imaging results. (author)

309

Laser-induced breakdown spectroscopy of archaeological findings with calibration-free inverse method: comparison with classical laser-induced breakdown spectroscopy and conventional techniques.  

Science.gov (United States)

A modified version of the calibration-free (CF) method was applied to the analysis of a set of archaeological brooches made of various copper-based alloys and coming from the archaeological site of Egnatia (Apulia, Southern Italy). The developed methodology consists in determining the plasma temperature by reversing the set of equations employed in the usual CF algorithm, and it is thus referred to as "inverse method". The plasma temperature is determined for one certified standard, by using its known elemental composition as an input data, and then applied to the set of unknown samples to evaluate their composition in a CF mode. The feasibility of such an approach is demonstrated by comparing the results obtained with classical LIBS (drawing calibration lines with a series of matrix-matched certified standards) and with independent measurements performed with a conventional technique (LA-ICP-MS). PMID:24528655

Gaudiuso, R; Dell'Aglio, M; De Pascale, O; Loperfido, S; Mangone, A; De Giacomo, A

2014-02-27

310

Methods of Pest Control and Direct Yield Loss Assessment of Country Bean (Dolichos lablab at Farmer`s Field Condition: A Survey Finding  

Directory of Open Access Journals (Sweden)

Full Text Available A survey on farmer`s pest control methods and direct yield loss assessment of country bean (Dolichos lablab was done during September 2000 to February 2001 in North Edilpur and South Mohadebpur villages of Sitakundu under Chittagong district. Results revealed that farmers used Fanfan, Nogos, Ripcord, Malathion, Roxion and Sumithion as chemical methods and applying ash and handpicking of insect pests as non-chemical method to control insect pests. The frequency of insecticide application during flowering stage to harvest was 9 to 15 with waiting period of only 3 to 20 days and 6 to 12 with waiting period of 3 to 25 days in North Edilpur and South Mohadebpur, respectively. The pod infestation by pod borer and aphids varied from 2.29 to 5.12% and from 2.83 to7.16% in North Edilpur and South Mohadebpur, respectively. Insect pests thus caused direct yield loss of 60.38-200.69 kg ha-1 in North Edilpur and 92.63-345.80 kg ha-1 in South Mohadebpur.

K.U. Ahmed

2004-01-01

311

Metáforas e Linguística de Corpus: metodologia de análise aplicada a um gênero de negócios / Metaphors and Corpus Linguistics: a method for finding metaphors in a business genre  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O presente trabalho visa a relatar o desenvolvimento de uma metodologia de identificação de metáforas em corpora eletrônicos. Como exemplo, foi tomado o gênero teleconferências de apresentação de resultados financeiros. A metodologia é do tipo "bottom-up" / "corpus-driven" e se baseia na identificaç [...] ão de palavras com frequência marcante (palavras-chave) e de seus padrões de co-ocorrência, seguido do cálculo de similaridade semântica entre essas palavras. Com isso, chega-se a um conjunto de palavras que são então interpretadas em seu co-texto, por meio de concordâncias. Abstract in english This paper aims at reporting the development of a method for metaphor identification in computer corpora. The method was tested on a particular corpus, namely of investment conference calls, and comprises procedures that work from the bottom up, and rely on marked frequency, collocation and semantic [...] similarity as signalling devices for metaphor. As such, the method is an example of corpus-driven research into metaphor. The application of these procedures yields a number of metaphor candidates, which are then checked manually through concordances.

Tony Berber, Sardinha.

312

Find an Endocrinologist  

Science.gov (United States)

... and charitable medical organization ABOUT AACE AACE Find an Endocrinologist The information in the AACE Find and ... greater medical health of the general public. Find an Endocrinologist Find an Endocrinologist in your area by ...

313

Finding Out Critical Points For Real-Time Path Planning  

Science.gov (United States)

Path planning for a mobile robot is a classic topic, but the path planning under real-time environment is a different issue. The system sources including sampling time, processing time, processes communicating time, and memory space are very limited for this type of application. This paper presents a method which abstracts the world representation from the sensory data and makes the decision as to which point will be a potentially critical point to span the world map by using incomplete knowledge about physical world and heuristic rule. Without any previous knowledge or map of the workspace, the robot will determine the world map by roving through the workspace. The computational complexity for building and searching such a map is not more than O( n2 ) The find-path problem is well-known in robotics. Given an object with an initial location and orientation, a goal location and orientation, and a set of obstacles located in space, the problem is to find a continuous path for the object from the initial position to the goal position which avoids collisions with obstacles along the way. There are a lot of methods to find a collision-free path in given environment. Techniques for solving this problem can be classified into three approaches: 1) the configuration space approach [1],[2],[3] which represents the polygonal obstacles by vertices in a graph. The idea is to determine those parts of the free space which a reference point of the moving object can occupy without colliding with any obstacles. A path is then found for the reference point through this truly free space. Dealing with rotations turns out to be a major difficulty with the approach, requiring complex geometric algorithms which are computationally expensive. 2) the direct representation of the free space using basic shape primitives such as convex polygons [4] and overlapping generalized cones [5]. 3) the combination of technique 1 and 2 [6] by which the space is divided into the primary convex region, overlap region and obstacle region, then obstacle boundaries with attribute values are represented by the vertices of the hypergraph. The primary convex region and overlap region are represented by hyperedges, the centroids of overlap form the critical points. The difficulty is generating segment graph and estimating of minimum path width. The all techniques mentioned above need previous knowledge about the world to make path planning and the computational cost is not low. They are not available in an unknow and uncertain environment. Due to limited system resources such as CPU time, memory size and knowledge about the special application in an intelligent system (such as mobile robot), it is necessary to use algorithms that provide the good decision which is feasible with the available resources in real time rather than the best answer that could be achieved in unlimited time with unlimited resources. A real-time path planner should meet following requirements: - Quickly abstract the representation of the world from the sensory data without any previous knowledge about the robot environment. - Easily update the world model to spell out the global-path map and to reflect changes in the robot environment. - Must make a decision of where the robot must go and which direction the range sensor should point to in real time with limited resources. The method presented here assumes that the data from range sensors has been processed by signal process unite. The path planner will guide the scan of range sensor, find critical points, make decision where the robot should go and which point is poten- tial critical point, generate the path map and monitor the robot moves to the given point. The program runs recursively until the goal is reached or the whole workspace is roved through.

Chen, Wei

1989-03-01

314

MANAGEMENT CONTROL SYSTEM AND THE CASE OF CSR IN THE TUNISIAN INDUSTRIAL COMPANIES: WHAT FINDINGS BY THE METHOD OF STRUCTURAL EQUATION?  

Directory of Open Access Journals (Sweden)

Full Text Available This study aims to the behavior of management control; it is providing a model to the behavior of integration of social responsibility in the management control tools. This model was validated with 306 Tunisian companies in the industrial sector. Through a questionnaire, the data collected are processed using exploratory and confirmatory analysis by the methods of structural equations. The results revealed that the management control system in industrial Tunisia is facing economic responsibility. This is in response to emerging pressures of uncertainty related to the environment, and in enrolling a strategy of domination by cost. In addition, the management control system is designed as a guidance tool actions and behaviors.

Hichem Dkhili

2013-01-01

315

Servicemembers and veterans with major traumatic limb loss from Vietnam war and OIF/OEF conflicts: Survey methods, participants, and summary findings  

Directory of Open Access Journals (Sweden)

Full Text Available Care of veterans and servicemembers with major traumatic limb loss from combat theaters is one of the highest priorities of the Department of Veteran Affairs. We achieved a 62% response rate in our Survey for Prosthetic Use from 298 Vietnam war veterans and 283 servicemembers/veterans from Operation Iraqi Freedom/Operation Enduring Freedom (OIF/OEF who sustained major traumatic limb loss. Participants reported their combat injuries; health status; quality of life; and prosthetic device use, function, rejection, and satisfaction. Despite the serious injuries experienced, health status was rated excellent, very good, or good by 70.7% of Vietnam war and 85.5% of OIF/OEF survey participants. However, many health issues persist for Vietnam war and OIF/OEF survey participants(respectively: phantom limb pain (72.2%/76.0%, chronic back pain (36.2%/42.1%, residual-limb pain (48.3%/62.9%, prosthesis-related skin problems (51.0%/58.0%, hearingloss (47.0%/47.0%, traumatic brain injury (3.4%/33.9%, depression (24.5%/24.0%, and posttraumatic stress disorder (37.6%/58.7%. Prosthetic devices are currently used by 78.2% of Vietnam war and 90.5% of OIF/OEF survey participants to improve function and mobility. On average, the annual rate for prosthetic device receipt is 10.7-fold higher for OIF/OEF than for Vietnam war survey participants. Findings from this cross-conflict survey identify many strengths in prosthetic rehabilitationfor those with limb loss and several areas for future attention.

Charles Maynard, PhD

2010-08-01

316

Factors influencing choices for colorectal cancer screening among previously unscreened African and Caucasian Americans: findings from a triangulation mixed methods investigation.  

Science.gov (United States)

We investigated factors that influence choice of colorectal cancer (CRC) screening test and assessed the most- and least-preferred options among fecal occult blood testing (FOBT), flexible sigmoidoscopy, colonoscopy, and double contrast barium enema among adults with varied race, gender, and geographic region demographics. Mixed methods data collection consisted of 10 focus group interviews and a survey of the 93 focus group participants. Participants were >or=50 years of age and reported not having been screened for colorectal cancer in the last ten years. Analyses examined differences by race, gender, and geographic location. Participants had modest knowledge about CRC and there were fewer correct answers to knowledge questions by African Americans. Participants recognized value of early detection, and identified health symptoms and their doctor's recommendation as influential for obtaining CRC screening. They chose colonoscopy and FOBT as the most preferred tests, while barium enema was least preferred. The analysis revealed intra-group variations in preference, though there were no significant differences by race, gender, or location. Openness of discussing this sensitive topic, lack of knowledge about colorectal cancer and screening costs, and diversity of preferences expressed within study groups suggest the importance of patient-physician dialogue about colorectal cancer screening options. New approaches to promoting colorectal cancer screening need to explore methods to facilitate patients establishing and expressing preferences among the screening options. PMID:19082695

Ruffin, Mack T; Creswell, John W; Jimbo, Masahito; Fetters, Michael D

2009-04-01

317

Factors Influencing Choices for Colorectal Cancer Screening Among Previously Unscreened African and Caucasian Americans: Findings from a Triangulation Mixed Methods Investigation  

Science.gov (United States)

We investigated factors that influence choice of colorectal cancer (CRC) screening test and assessed the most- and least-preferred options among fecal occult blood testing (FOBT), flexible sigmoidoscopy, colonoscopy, and double contrast barium enema among adults with varied race, gender, and geographic region demographics. Mixed methods data collection consisted of 10 focus group interviews and a survey of the 93 focus group participants. Participants were ?50 years of age and reported not having been screened for colorectal cancer in the last ten years. Analyses examined differences by race, gender, and geographic location. Participants had modest knowledge about CRC and there were fewer correct answers to knowledge questions by African Americans. Participants recognized value of early detection, and identified health symptoms and their doctor's recommendation as influential for obtaining CRC screening. They chose colonoscopy and FOBT as the most preferred tests, while barium enema was least preferred. The analysis revealed intra-group variations in preference, though there were no significant differences by race, gender, or location. Openness of discussing this sensitive topic, lack of knowledge about colorectal cancer and screening costs, and diversity of preferences expressed within study groups suggest the importance of patient-physician dialogue about colorectal cancer screening options. New approaches to promoting colorectal cancer screening need to explore methods to facilitate patients establishing and expressing preferences among the screening options. PMID:19082695

Ruffin, Mack T.; Creswell, John W.; Jimbo, Masahito

2014-01-01

318

A Fast and Stable Cluster Labeling Method for Support Vector Clustering  

Directory of Open Access Journals (Sweden)

Full Text Available Even though support vector clustering (SVC is able to handle arbitrary cluster shapes effectively, its popularity is frequently degraded by highly intensive time complexity, poor label performance and even instability for efficiency. To overcome such problems, a fast and stable cluster labeling (FSCL method is proposed. Based on stable equilibrium points, the FSCL first finds an appropriate division of support vectors. With a nonlinear sample sequence strategy presented here, the connected components profiled by support vectors (SVs can be determined in terms of sampling all stable equilibrium point pairs; and the FSCL prefers a density centroid constructed by one subset of SVs, along with a stable equilibrium point, to represent a component while avoiding local optimization. Finally, the remaining data points can be assigned the label of the nearest components with respect to a weighted distance. Time complexity analysis and comparative experiments suggest that the FSCL improves both the efficiency and clustering quality significantly while guaranteeing stability.  

Huina Li

2013-12-01

319

Application of Monte-Carlo method for finding of ionization and secondary emission coefficients and volt-ampere characteristics of Townsend discharge in hydrogen  

International Nuclear Information System (INIS)

The coefficients of ? secondary cathode emission for hydrogen is determined experimentally via calculation of the ionization numbers within the gaps by the Monte-Carlo method. In this case, one calculates the ionization frequencies, the Townsend ionization coefficients (demonstrating their nonlocality), the electron drift rate, the probability of the emitted electron return to the cathode. The calculated parameters are in line with the measured ones. One studied the gaps with pd=0.37-17 Torrxcm. It is shown that just for pd within the Paschen curve minimum vicinity the observed negative differential resistance of the Townsend discharge may be associated with the reduction of the probability of the electron return to the cathode at E/N increase

320

Costs and effects of a 'healthy living' approach to community development in two deprived communities: findings from a mixed methods study  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Inequalities in health have proved resistant to 'top down' approaches. It is increasingly recognised that health promotion initiatives are unlikely to succeed without strong local involvement at all stages of the process and many programmes now use grass roots approaches. A healthy living approach to community development (HLA was developed as an innovative response to local concerns about a lack of appropriate services in two deprived communities in Pembrokeshire, West Wales. We sought to assess feasibility, costs, benefits and working relationships of this HLA. Methods The HLA intervention operated through existing community forums and focused on the whole community and its relationship with statutory and voluntary sectors. Local people were trained as community researchers and gathered views about local needs though resident interviews. Forums used interview results to write action plans, disseminated to commissioning organisations. The process was supported throughout through the project. The evaluation used a multi-method before and after study design including process and outcome formative and summative evaluation; data gathered through documentary evidence, diaries and reflective accounts, semi-structured interviews, focus groups and costing proformas. Main outcome measures were processes and timelines of implementation of HLA; self reported impact on communities and participants; community-agency processes of liaison; costs. Results Communities were able to produce and disseminate action plans based on locally-identified needs. The process was slower than anticipated: few community changes had occurred but expectations were high. Community participants gained skills and confidence. Cross-sector partnership working developed. The process had credibility within service provider organisations but mechanisms for refocusing commissioning were patchy. Intervention costs averaged £58,304 per community per annum. Conclusions The intervention was feasible and inexpensive, with indications of potential impact at individual, community and policy planning levels. However, it is a long term process which requires sustained investment and must be embedded in planning and service delivery processes.

Skone Jon

2011-01-01

 
 
 
 
321

Measurement method for finding gas adsorption equilibrium isotherms by employing a gas chromatograph and using its integrator in a new way  

Science.gov (United States)

A method for measuring the adsorption ability of zeolites has been developed. The adsorption can be accurately measured over a wide range of pressures and temperatures. The range usually covered is partial pressures ranging from 0.2 to 20 bar (a) and temperatures from 10 to 50 °C. However, it may be extended to 0.1-25 bar (a) and -40-80°C. When a partial pressure below 2 bar (a) is to be used, the gas is diluted with helium. The method is built around a gas chromatograph (GC) equipped with a thermal conductivity detector (TCD) and having a programming and peak integrating unit. It also has an option using liquid nitrogen to allow work below ambient temperature. The GC has been modified with two special columns to be used alternately for purging with helium and as test chamber for the measurements. It is also equipped with a separate external flow and pressure-handling unit. The GC is used, not as a chromatograph, but instead to integrate suitably interrupted breakthrough curves. The primary measured data are evaluated using a program written in BASIC, which separates the part of the primary measured results that originates from the adsorption from the part that is induced by the measuring equipment. Using a calibration file that can easily be updated from within the program, this separation has achieved a high degree of accuracy. Using the adsorption data from these measurements, Langmuir-type isotherm equations are fitted, which accurately represent the adsorption of the tested gas both with respect to pressure and to temperature. It has been found that adsorption data measured in this way can achieve a standard deviation between measured and calculated data that typically varies around 1% over the whole measured range. In order to do this, however, in the case of nitrogen adsorption the sum of two Langmuir isotherms has to be used. This is not needed with oxygen or argon adsorption.

Eriksson, Tore; Sylwan, Christopher

2005-04-01

322

How possible is the development of an operational psychometric method to assess the presence of the 5-HTTLPR s allele? Equivocal preliminary findings  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Objective The s allele of the 5-hydroxytryptamine transporter-linked promoter region (5-HTTLPR polymorphism of the serotonin transporter gene has been found to be associated with neuroticism-related traits, affective temperaments and response to selective serotonin reuptake inhibitor (SSRI treatment. The aim of the current study was to develop a psychometric tool that could at least partially substitute for laboratory testing and could predict the presence of the s allele. Methods The study included 138 women of Caucasian origin, mean 32.20 ± 1.02 years old. All subjects completed the Hungarian standardised version of the Temperament Evaluation of the Memphis, Pisa, Paris, and San Diego Autoquestionnaire (TEMPS-A instrument and were genotyped for 5-HTTLPR using PCR. The statistical analysis included the calculation of the Index of Discrimination (D, Discriminant Function Analysis, creation of scales on the basis of the above and then item analysis and calculation of sensitivity and specificity. Results Four indices were eventually developed, but their psychometric properties were relatively poor and their joint application did not improve the outcome. Conclusions We could not create a scale that predicts the 5-HTTLPR genotype with sufficient sensitivity and specificity, therefore we could not substitute a psychometric scale for laboratory genetic testing in predicting genotype, and also possibly affective disorder characterisation and treatment.

Laszik Andras

2010-05-01

323

Knockout subtraction autoradiography: a novel ex vivo method to detect heteromers finds sparse KOP receptor/DOP receptor heterodimerization in the brain.  

Science.gov (United States)

Several methodological approaches suggest that receptor heteromers exist in cell systems, but their presence in physiological tissue is widely contentious. We describe a novel method to determine if heterodimers exist in brain tissue sections using autoradiographic binding comparisons from single and double gene knockout mice, where tissues either have a full receptor complement and can form heterodimers, or are incapable of making heterodimers. We have tested this model, which we have named Knockout Subtraction Autoradiography, to determine if heterodimerisation of the kappa (KOP) and delta opioid (DOP) receptors occurs, as evidence from binding studies in cell systems suggest they are present in the brain. Using labeling of putative KOP receptor/DOP receptor heterodimers with either [(3)H]bremazocine or with [(3)H]naltrindole, two ligands which were used to provide evidence suggesting that these opioid receptor subtypes heterodimerize, we have applied a subtraction equation model based on the principle that receptor gene double knockout of either MOP receptor/KOP receptor (DOP receptor expression only) or MOP receptor/DOP receptor (KOP receptor expression only) produces tissue incapable of making the KOP receptor/DOP receptor heterodimer. We have shown in most brain regions that the labeling fits a simple additive model of monomer labeling, but that in a few brain regions opioid receptor heterodimerization does occur. The data does not support the conclusion that KOP receptor/DOP receptor heterodimerisation is widespread in the central nervous system, but does indicate that this novel methodology can detect heterodimerisation, when ligands with distinct binding affinities for monomer and heterodimer forms exist. PMID:24657279

Yoo, Ji-Hoon; Bailey, Alexis; Borsodi, Anna; Tóth, Géza; Matifas, Audrey; Kieffer, Brigitte L; Kitchen, Ian

2014-05-15

324

Aplicação do delineamento simplex-centroide no estudo da cinética da oxidação de biodiesel B100 em mistura com antioxidantes sintéticos / The simplex-centroid design applied to study of the kinetics of the oxidation of B100 biodiesel in blend with synthetic antioxidants  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese [...] Abstract in english Antioxidants are an alternative to prevent or slow the degradation of the biofuel. In this study, it was evaluated the oxidative stability of B100 biodiesel from soybean oil in the presence of three commercial synthetic antioxidants, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and [...] tert-butylhydroquinone (TBHQ), pure or blended, from the experimental design of simplex-centroid mixture. The reaction order and rate constant were also calculated for all tests. The treatment containing pure TBHQ proved to be the most effective, proven by design, the optimum mix obtained and the rate constant. Binary and ternary mixtures containing TBHQ also showed appreciable antioxidant effect.

Dionísio, Borsato; Luiz Henrique, Dall' Antonia; Carmen Luísa B., Guedes; Elaine Cristina R., Maia; Heverson Renan de, Freitas; Ivanira, Moreira; Kelly Roberta, Spacino.

1726-17-01

325

Aplicação do delineamento simplex-centroide no estudo da cinética da oxidação de biodiesel B100 em mistura com antioxidantes sintéticos / The simplex-centroid design applied to study of the kinetics of the oxidation of B100 biodiesel in blend with synthetic antioxidants  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese [...] Abstract in english Antioxidants are an alternative to prevent or slow the degradation of the biofuel. In this study, it was evaluated the oxidative stability of B100 biodiesel from soybean oil in the presence of three commercial synthetic antioxidants, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and [...] tert-butylhydroquinone (TBHQ), pure or blended, from the experimental design of simplex-centroid mixture. The reaction order and rate constant were also calculated for all tests. The treatment containing pure TBHQ proved to be the most effective, proven by design, the optimum mix obtained and the rate constant. Binary and ternary mixtures containing TBHQ also showed appreciable antioxidant effect.

Dionísio, Borsato; Luiz Henrique, Dall' Antonia; Carmen Luísa B., Guedes; Elaine Cristina R., Maia; Heverson Renan de, Freitas; Ivanira, Moreira; Kelly Roberta, Spacino.

326

Abdominal aspergillosis: CT findings  

Energy Technology Data Exchange (ETDEWEB)

Objective: In order to retrospectively evaluate the CT findings of abdominal aspergillosis in immunocompromised patients. Materials and methods: CT scans were reviewed with regard to the sites, number, morphologic appearance, attenuation, and the contrast enhancement patterns of the lesions in six patients (5 women, 1 man; mean age, 43.4 years; range, 23-59 years) with pathologically proved abdominal aspergillosis by two gastrointestinal radiologists in consensus. Medical records were also reviewed to determine each patient's clinical status and outcome. Results: All patients were immunocompromised state: 4 patients received immunosuppressive therapy for solid organ transplantation and 2 patients received chemotherapy for acute myeloid leukemia. Aspergillosis involved blood vessels (n = 3), liver (n = 2), spleen (n = 2), gastrointestinal tract (n = 2), native kidney (n = 1), transplanted kidney (n = 1), peritoneum (n = 1), and retroperitoneum (n = 1). CT demonstrated solid organ or bowel infarction or perforation secondary to vascular thrombosis or pseudoaneurysm, multiple low-attenuating lesions of solid organs presenting as abscesses, concentric bowel wall thickening mimicking typhlitis, or diffuse or nodular infiltration of the peritoneum and retroperitoneum. Conclusion: Familiarity with findings commonly presenting as angioinvasive features or abscesses on CT, may facilitate the diagnosis of rare and fatal abdominal aspergillosis.

Yeom, Suk Keu, E-mail: pagoda20@hanmail.net [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap2-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of); Kim, Hye Jin, E-mail: kimhyejin@amc.seoul.kr [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap2-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of); Byun, Jae Ho, E-mail: jhbyun@amc.seoul.kr [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap2-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of); Kim, Ah Young, E-mail: aykim@amc.seoul.kr [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap2-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of); Lee, Moon-Gyu, E-mail: mglee@amc.seoul.kr [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap2-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of); Ha, Hyun Kwon, E-mail: hkha@amc.seoul.kr [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap2-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of)

2011-03-15

327

Radiological findings in angiofibroma  

International Nuclear Information System (INIS)

Surgery after pre-operative embolization has become the main treatment modality in angiofibroma therapy. As surgical planning is based on precise pre-operative tumour evaluation, knowledge of the characteristic growth patterns is of great interest. Analysis of tumour extension and blood supply, as well as methods of controlling intra-operative bleeding, help in determining the appropriate surgical approach. Though benign, angiofibroma demonstrates a locally aggressive nature. This fibrovascular tumour is characterised by typical radiological findings and by predictable growth patterns. The tumour extension and blood supply can be accurately determined by CT, MR imaging and angiography. With classic radiological findings, no pre-operative biopsy is necessary in most angiofibromas. Advances in radiological imaging have contributed to improved surgical planning and tumour resection. The surgeon is able to select the least traumatic approach with secure haemostatic control, which is also critical for avoiding the disturbance of facial skeletal growth in this group of young patients. Embolization, pre-operative autologous donation and the cell saver system for immediate retransfusion of the collected blood after filtration, are important tools for dealing with blood loss in angiofibroma surgery as they minimize homologous blood transfusion

328

Finding Cryptography in Object Code  

Energy Technology Data Exchange (ETDEWEB)

Finding and identifying Cryptography is a growing concern in the malware analysis community. In this paper, a heuristic method for determining the likelihood that a given function contains a cryptographic algorithm is discussed and the results of applying this method in various environments is shown. The algorithm is based on frequency analysis of opcodes that make up each function within a binary.

Jason L. Wright

2008-10-01

329

Studying Distance Students: Methods, Findings, Actions  

Science.gov (United States)

University of North Texas (UNT) Libraries began studying the library needs of distance learners in 2009 using a variety of approaches to explore and confirm these needs as well as obtain input into how to meet them. Approaches used to date include analysis of both quantitative and qualitative responses by online students to the LibQUAL+[R] surveys…

Wahl, Diane; Avery, Beth; Henry, Lisa

2013-01-01

330

Finding Maximal Quasiperiodicities in Strings  

DEFF Research Database (Denmark)

Apostolico and Ehrenfeucht defined the notion of a maximal quasiperiodic substring and gave an algorithm that finds all maximal quasiperiodic substrings in a string of length n in time O(n log2 n). In this paper we give an algorithm that finds all maximal quasiperiodic substrings in a string of length n in time O(n log n) and space O(n). Our algorithm uses the suffix tree as the fundamental data structure combined with efficient methods for merging and performing multiple searches in search trees. Besides finding all maximal quasiperiodic substrings, our algorithm also marks the nodes in the suffix tree that have a superprimitive path-label.

Brodal, Gerth StØlting; Pedersen, Christian N. S.

2000-01-01

331

MRI finding of hemangioblastomas  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study is to evaluate the findings of magnetic resonance imaging (MRI) of posterior fossa hemanangioblastoma and usefulness of contrast enhancement with Gd-DTPA. Seven patients with posterior fossa hemangioblastoma were studied with both pre- and post-enhanced MRI. The MR images were reviewed regarding the location, size, signal intensities of cysts and mural nodules, and their contrast enhancement pattern. Five tumors were located in cerebellar hemisphere, one in vermis, and one in posterior part of medulla. One patient with von Hippel-Lindau disease had a medullary hemangioblastoma with multiple pancreatic cysts. In 6 cases, the major portion of the tumor was cysts and had small mulkal nodules. The solid portion was relatively lange in one cases, cemprising half of the tumor cysts were oval shaped and their sized were 3-6.7 cm in diameter. In five cases(71%), septations were noted within the cysts. Cysts were isointense or slightly hyperintense on T1-weighted image and hyperintense on T2- weighted image compared with cerebrospinal fluid. Mural nodules were oval or rounded radiotherapy had better prognosis than those treated with radiotherapy alwas 0.5-2.5 cm in diameter. Mural nodules were isointense to gray matter. They were detected in five cases on T1-weighted images and one case on T2-weighted images. In two cases, vascular signal void area was noted in mural nodules. On contrast-enhanced T1-weighted images, all mural nodules were intensely enhanced. MRI provide to be a good diagnostic method to detect and characterize posterior fossa hemangioblastoma. The most common finding is Cystic posterior fossa lesion with enhancing mural nodule. Contrast enhancement is essential for specific diagnosis.

Park, Seung Cheol; Oh, Min Cheol; Chung, Hwan Hoon; Seol, Hye Young; Lee, Nam Joon; Kim, Jung Hyuk [Korea University College of Medicine, Seoul (Korea, Republic of)

1994-05-15

332

Find a Plume, Find a Vent  

Science.gov (United States)

This classroom activity gives students an appreciation for the difficulties deep sea researchers must face in order to find hydrothermal vents. Working in small groups, students can complete this Web investigation in a single class period. The printable handout includes a series of inquiry-based questions that prompt students to use what they already know about mid-ocean ridges to hypothesize about how scientists locate deep sea vents, detailed directions for a Web research project that takes them on a virtual deep sea journey investigating hydrothermal vents, and a worksheet that helps students apply their building knowledge to locate a vent in the northern Pacific Ocean.

333

DBGSA: a novel method of distance-based gene set analysis.  

Science.gov (United States)

When compared with single gene functional analysis, gene set analysis (GSA) can extract more information from gene expression profiles. Currently, several gene set methods have been proposed, but most of the methods cannot detect gene sets with a large number of minor-effect genes. Here, we propose a novel distance-based gene set analysis method. The distance between two groups of genes with different phenotypes based on gene expression should be larger if a certain gene set is significantly associated with the given phenotype. We calculated the distance between two groups with different phenotypes, estimated the significant P-values using two permutation methods and performed multiple hypothesis testing adjustments. This method was performed on one simulated data set and three real data sets. After a comparison and literature verification, we determined that the gene resampling-based permutation method is more suitable for GSA, and the centroid statistical and average linkage statistical distance methods are efficient, especially in detecting gene sets containing more minor-effect genes. We believe that this distance-based method will assist us in finding functional gene sets that are significantly related to a complex trait. Additionally, we have prepared a simple and publically available Perl and R package (http://bioinfo.hrbmu.edu.cn/dbgsa or http://cran.r-project.org/web/packages/DBGSA/). PMID:22786580

Li, Jin; Wang, Limei; Xu, Liangde; Zhang, Ruijie; Huang, Meilin; Wang, Ke; Xu, Jiankai; Lv, Hongchao; Shang, Zhenwei; Zhang, Mingming; Jiang, Yongshuai; Guo, Maozu; Li, Xia

2012-10-01

334

Finding solution by Tabu search  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, the method of finding the solution by Tabu search is addressed. Tabu search is one of the local search heuristics, which has been applied extensively in operations research works. In this paper, the basic concepts of the Tabu search heuristic and some examples of applying this search technique in operations research problems are presented.

Ratanamanee, W.

2003-11-01

335

MEMS AO for Planet Finding  

Science.gov (United States)

This slide presentation reviews a method for planet finding using microelectromechanical systems (MEMS) Adaptive Optics (AO). The use of a deformable mirror (DM) is described as a part of the instrument that was designed with a nulling interferometer. The strategy that is used is described in detail.

Rao, Shanti; Wallace, J. Kent; Shao, Mike; Schmidtlin, Edouard; Levine, B. Martin; Samuele, Rocco; Lane, Benjamin; Chakrabarti, Supriya; Cook, Timothy; Hicks, Brian; Jung, Paul

2008-01-01

336

O centróide da piscina de água quente do pacífico como um indicador dos fenômenos El Niño e La Niña / The centroid of the pacific warm pool as an index for the El Niño and La Niña phenomena  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Os fenômenos oceanográficos El Niño e La Niña foram analisados através do monitoramento da série temporal da componente zonal do centroide da piscina de água quente do Pacífico (PAQ) que descreve movimentos leste-oeste ao longo da faixa intertropical deste oceano. Utilizou-se uma série de dados de t [...] emperatura da superfície do Oceano Pacífico para classificar a PAQ e estimar o seu centroide entre 1981 e 2003. Todos os episódios de El Niño (1982-83; 1986-87; 1990-95; e 1997-98) e La Niña (1984-85; 1988-89; 1998-2000) existentes no período analisado puderam ser observados na série temporal de dados da componente zonal da PAQ (CZPAQ). Os episódios mais intensos de El Niño foram classificados pela ordenação decrescente dos maiores deslocamentos para leste (ranking). A série de dados da CZPAQ se apresentou em fase com o índice de Oscilação Sul e com a anomalia da temperatura superficial do oceano (TSO). As flutuações associadas ao movimento zonal do centroide da PAQ foram observadas no espectro de energia onde ficaram ressaltadas as flutuações interanuais associadas aos fenômenos El Niño e La Niña. Foram observados deslocamentos mais curtos para oeste durante os anos de La Niña, quando comparados aos deslocamentos para leste durante os eventos de El Niño. A migração zonal da PAQ, representada aqui pelo centroide, apresentou-se, portanto, como um indicador dos fenômenos El Niño e La Niña. A principal vantagem dessa técnica é a dependência de um único parâmetro arbitrário, que é o limiar da TSO para delinear a PAQ. Abstract in english The El Niño -La Niña oceanographic phenomena were analized making use of the zonal component of the Pacific warm pool (PAQ) which describes east-west displacements along the intertropical belt of this ocean. We manipulated an ocean surface temperature (TSO) timeseries to classify the PAQ and to esti [...] mate its centroid between 1981 and 2003. All the El Niño (1982-83; 1986-87; 1990-95; e 1997-98) and La Niña (1984-85; 1988-89; 1998-2000) episodes described in the academic literature were eminent in the timeserie of the zonal component of the Pacific warm pool (CZPAQ). The most intense El Niño episodes were ranked according to its furthest eastward displacement. The timeserie of the CZPAQ was in phase with both the TSO anomaly and the Southern Oscillation Index. The fluctuations associated to the CZPAQ were illustraded in the spectrum where interannual oscillations associated to the El Niño -La Niña phenomena were observed. Shorter migrations to the west during the La Niña years were notable in comparison to those eastward moviments during the El Niño events. Therefore, the zonal displacements of the PAQ, represented here by the centroid, were presented as having significant worth to indicate the El Niño and La Niña phenomena. The main advantage of this technique is that it depends on a single arbitrary parameter to represent the PAQ, the threshold of the ocean surface temperature in the Pacific Ocean.

Fabio Vieira, Machado; Victor de Amorim, d' Ávila.

337

O centróide da piscina de água quente do pacífico como um indicador dos fenômenos El Niño e La Niña / The centroid of the pacific warm pool as an index for the El Niño and La Niña phenomena  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Os fenômenos oceanográficos El Niño e La Niña foram analisados através do monitoramento da série temporal da componente zonal do centroide da piscina de água quente do Pacífico (PAQ) que descreve movimentos leste-oeste ao longo da faixa intertropical deste oceano. Utilizou-se uma série de dados de t [...] emperatura da superfície do Oceano Pacífico para classificar a PAQ e estimar o seu centroide entre 1981 e 2003. Todos os episódios de El Niño (1982-83; 1986-87; 1990-95; e 1997-98) e La Niña (1984-85; 1988-89; 1998-2000) existentes no período analisado puderam ser observados na série temporal de dados da componente zonal da PAQ (CZPAQ). Os episódios mais intensos de El Niño foram classificados pela ordenação decrescente dos maiores deslocamentos para leste (ranking). A série de dados da CZPAQ se apresentou em fase com o índice de Oscilação Sul e com a anomalia da temperatura superficial do oceano (TSO). As flutuações associadas ao movimento zonal do centroide da PAQ foram observadas no espectro de energia onde ficaram ressaltadas as flutuações interanuais associadas aos fenômenos El Niño e La Niña. Foram observados deslocamentos mais curtos para oeste durante os anos de La Niña, quando comparados aos deslocamentos para leste durante os eventos de El Niño. A migração zonal da PAQ, representada aqui pelo centroide, apresentou-se, portanto, como um indicador dos fenômenos El Niño e La Niña. A principal vantagem dessa técnica é a dependência de um único parâmetro arbitrário, que é o limiar da TSO para delinear a PAQ. Abstract in english The El Niño -La Niña oceanographic phenomena were analized making use of the zonal component of the Pacific warm pool (PAQ) which describes east-west displacements along the intertropical belt of this ocean. We manipulated an ocean surface temperature (TSO) timeseries to classify the PAQ and to esti [...] mate its centroid between 1981 and 2003. All the El Niño (1982-83; 1986-87; 1990-95; e 1997-98) and La Niña (1984-85; 1988-89; 1998-2000) episodes described in the academic literature were eminent in the timeserie of the zonal component of the Pacific warm pool (CZPAQ). The most intense El Niño episodes were ranked according to its furthest eastward displacement. The timeserie of the CZPAQ was in phase with both the TSO anomaly and the Southern Oscillation Index. The fluctuations associated to the CZPAQ were illustraded in the spectrum where interannual oscillations associated to the El Niño -La Niña phenomena were observed. Shorter migrations to the west during the La Niña years were notable in comparison to those eastward moviments during the El Niño events. Therefore, the zonal displacements of the PAQ, represented here by the centroid, were presented as having significant worth to indicate the El Niño and La Niña phenomena. The main advantage of this technique is that it depends on a single arbitrary parameter to represent the PAQ, the threshold of the ocean surface temperature in the Pacific Ocean.

Fabio Vieira, Machado; Victor de Amorim, d' Ávila.

2014-09-01

338

A novel method of spectrum stabilization  

International Nuclear Information System (INIS)

A new type of spectrum stabilizer for a scintillation spectrometer is described. A pulse light source DM 160 is used to introduce an artificial peak in the spectrum at a convenient energy. The centroid of pulse spectrum corresponding to artificial peak is compared with that of suitable reference pulses obtained from the DM 160 driver circuit. Any drift in artificial peak produces a d.c. voltage at the output of centroid comparator and this voltage is used to control the gain of variable gain amplifier to counter the drift. With suitable adjustment the effect of any variation in pulse height of DM 160 driving pulse can be compensated so that the spectrometer gain is independent of any variation, drift etc. in the height of pulse driving DM 160 tube. This circuit is simple and gives improved performance compared to 2 channel method of obtaining the control voltage for variable gain amplifier. (author)

339

CT findings of colonic diverticulitis  

Energy Technology Data Exchange (ETDEWEB)

Although colonic diverticulitis has no indication for operation, but in some mistaken cases were operated with a diagnosis of acute appendicitis. We evaluated the CT findings of colonic diverticulitis about 19 cases and of asymptomatic colonic diverticula about 15 cases retrospectively. Diagnosis was confirmed of barium enema and operation. CT are complementary methods of examination that can delineated the range of thickening of the colon and the extension of inflammatory changes around the colon. We also believe that CT findings of colonic diverticulitis are useful for differentiating from a diagnosis of appendicitis. (author)

Sasaki, Shigeru; Ohba, Satoru [Nagoya City Univ. (Japan). Medical School; Mizutani, Masaru [and others

1998-11-01

340

CT findings of colonic diverticulitis  

International Nuclear Information System (INIS)

Although colonic diverticulitis has no indication for operation, but in some mistaken cases were operated with a diagnosis of acute appendicitis. We evaluated the CT findings of colonic diverticulitis about 19 cases and of asymptomatic colonic diverticula about 15 cases retrospectively. Diagnosis was confirmed of barium enema and operation. CT are complementary methods of examination that can delineated the range of thickening of the colon and the extension of inflammatory changes around the colon. We also believe that CT findings of colonic diverticulitis are useful for differentiating from a diagnosis of appendicitis. (author)

 
 
 
 
341

Hysterosalpingographic findings in infertility  

International Nuclear Information System (INIS)

Four hundred and fifty four cases of H.S.G. in infertility were analyzed and following brief results were obtained. 1. Most frequent age group was 25-29 year old, and those number of patient were 188 (41.4%). 2. Most frequent abnormal uterine findings was intravasation (113 cases), and malposition (119), irregular margin (104), filling defect (37), and diverticulum (6) in decreasing order. 3. Most frequent abnormal tubal finding was obstruction (199 cases), and hydrosalpinx (99), diverticulosis (22), intravasation (17), peritubal adhesion (13), and beaded tube (10) in decreasing order. 4. Nagative findings was seen in 155 cases (34.1%) of uterus and in 227 cases (50.0%) of fallopian tubes. 5. Nagative findings in both uterus and fallopian tubes was seen only 87 cases (19.2%)

342

Hysterosalpingographic findings in infertility  

Energy Technology Data Exchange (ETDEWEB)

Four hundred and fifty four cases of H.S.G. in infertility were analyzed and following brief results were obtained. 1. Most frequent age group was 25-29 year old, and those number of patient were 188 (41.4%). 2. Most frequent abnormal uterine findings was intravasation (113 cases), and malposition (119), irregular margin (104), filling defect (37), and diverticulum (6) in decreasing order. 3. Most frequent abnormal tubal finding was obstruction (199 cases), and hydrosalpinx (99), diverticulosis (22), intravasation (17), peritubal adhesion (13), and beaded tube (10) in decreasing order. 4. Nagative findings was seen in 155 cases (34.1%) of uterus and in 227 cases (50.0%) of fallopian tubes. 5. Nagative findings in both uterus and fallopian tubes was seen only 87 cases (19.2%)

Park, M. S.; Kim, K. S.; Kim, J. S.; Bai, B. C. [Seoul Red Cross Hospital, Seoul (Korea, Republic of)

1981-12-15

343

Find a Healthcare Professional  

Science.gov (United States)

... 459073320|||40.6128631|||-75.5292302|||Dr. Frederic A. Stelzer, M.D.|||1501 North Cedar Crest Boulevard #110||| ... living-with-crohns-colitis/find-a-doctor/Frederic-Stelzer.html||| 336742213|||38.6354444|||-90.263063|||Dr. William ...

344

Find an Endocrinologist  

Science.gov (United States)

... Endocrinologist Learn About Clinical Trials Featured Resource Educational Infographics View Featured Resource Menopause Map™ View Find an ... Healthy Living Living Your Best Life with Diabetes Infographics Myth vs Fact Patient Alerts Scientific Statements Social ...

345

Aortic Coarctation: Radiologic Findings  

International Nuclear Information System (INIS)

Aortic coarctation is an infrequent vascular malformation that causes arterial hypertension. Some signs have been described in the physical examination. They strongly suggest the diagnosis, nevertheless it is not easy to identify these findings in all patients, and is in these cases where radiologic studies suggest and confirm the diagnosis. In this article we present the case of a patient with aortic coarctation and we correlate the radiographic, angiographic-spiral CT and renal Doppler findings.

346

Lasers, Let's Find 'Em!  

Science.gov (United States)

Students research particular types of lasers and find examples of how they are used in technology today. Teams present their findings by means of PowerPoint presentations, videos or brochures. The class takes notes on the presentations using a provided handout. This activity prepares students for the "go public" phase of the legacy cycle in which they solve the grand challenge by designing and producing a laser-based security system.

VU Bioengineering RET Program, School of Engineering,

347

Radiologic findings of emphysematous pyelonephritis  

International Nuclear Information System (INIS)

Emphysematous pyelonephritis is a rare, life threatening infection of kidney and the perinephric space, characterized by the production of gas within the renal parenchyma. The aim of this study is to analyze the clinical and radiologic characteristics of emphysematous pyelonephritis. We reviewed 7 cases of the emphysematous pyelonephritis. Six patients had plain abdominal radiographs, ultrasonograms and abdominal CT scans. Only one patient had plain radiograph and ultrasonogram. In 5 operated cases, CT findings were compared with surgical records. Plain radiographs showed characteristic diffuse mottling of gas in renal fossa. On sonogram, intrarenal gas was identified as echogenic foci with dirty shadows. CT scan showed inflammatory mass with gas and fluid levels in adjacent to the kidney. CT findings corresponded relatively wall with the surgical findings in regard to disease extent. Intrarenal gas in appropriate clinical setting is highly specific for emphysematous pyelonephritis. CT is the most sensitive method for demonstrating the disease extent as well as specific diagnosis

348

Imaging findings in pleuropulmonary blastoma  

Energy Technology Data Exchange (ETDEWEB)

Pleuropulmonary blastoma (PPB) is a rare tumor of the chest seen in young children and recently recognized as distinct from the pulmonary blastoma typically encountered in adults. The purpose of this study is to review and describe the findings of PPB on radiography and CT in four patients. Methods: Radiographs and CT findings were reviewed in four patients with pathologically proven PPB. All four cases demonstrated large masses in the right hemithorax with heterogeneous low attenuation, pleural effusion, contralateral mediastinal shift, and lack of chest wall invasion. When a large pleural-based mass is identified in a young child, PPB should be considered. Suggestive findings include absence of chest wall invasion, presence of pleural fluid, right-sided location, and heterogeneous low attenuation. (orig.)

Naffaa, Lena N.; Donnelly, Lane F. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States)

2005-04-01

349

A modified semi-supervised color image segmentation method  

Directory of Open Access Journals (Sweden)

Full Text Available The paper proposed a modified color image segmentation method basing on semi-supervised hidden Markov random fields (HMRF with constraints. Making use of MeanShift algorithm to get supervision information and, cluster number and initial values for cluster centroids, color images can be segmented effectively with the method in this paper by K-Means algorithm. The experimental results are very encouraging.

Chai Fangyong

2012-08-01

350

[Incidental bronchoscopic findings].  

Science.gov (United States)

Inflexible and flexible bronchoscopy represents a standard diagnostic procedure in pneumology. Besides lung carcinomas, which is the most frequent indication for diagnostic bronchoscopy, a plethora of clinical symptoms such as chronic persistent cough, hoarseness, unexplained dyspnea, hemoptysis, and suspicious findings on auscultation require further endoscopic evaluation. Moreover, bronchoscopy plays a central role in the diagnostic work-up of interstitial lung diseases and persistent lung infiltrates, in particular those of infectious origin (e.g., fungal, viral, tuberculous, and Pneumocystis jiroveci infections). In addition, diagnostic bronchoscopy has more recently been complemented by endobronchial ultrasound (EBUS). EBUS is predominantly employed for the accurate diagnosis and mediastinal staging of lung carcinomas, and the assessment of lympadenopathy-associated diseases such as sarcoidosis.Since endoscopic evaluation is typically preceded by computed tomography (CT) of the chest, genuine incidental findings occur relatively seldom and usually account for pathological findings that have been missed on conventional imaging approaches. For instance, characteristic incidental findings include benign and malignant tumors in the area of the endoscopic access and central airways, anatomical variations and (vascular) malformations, tracheal and bronchial airway alterations, and aspirated objects. This review focuses on bronchoscopic findings that have either been completely missed by conventional imaging or differently interpreted due to its radiologic morphology. PMID:25146679

Holland, A; Eberhardt, R

2014-09-01

351

CT findings of periappendiceal abscesses  

International Nuclear Information System (INIS)

CT has been widely used in the diagnosis of intra-abdominal abscesses, but its findings of periappendiceal abscesses are not well known. CT findings of 15 cases of periappendiceal abscesses were analyzed retrospectively. The results were as follows; 1.The most prevalent age groups were 5th. and 6th. decades and a male to female ratio was 7:8. 2.CT findings of periappendiceal abscesses were cystic low density mass in 7 cases (46.5%), solid soft tissue mass in 2 patients (13.5%) and mixed density mass in 6 cases (40%). 3.Associated CT findings were fat plane obliteration in 12 cases (80%), fascial thickening in 10 cases (66%), enhancing wall in 7 cases (46.5%), internal air density in 5 cases (33%), cecal wall thickening in 3 cases (20%) and ascites in 2 cases (13.5%). 4.Abscess was localized in RLQ medial to cecum in 10 cases (66%), extended to posterior pararenal space in 2 cases (13.5%), pelvic cavity in 2 cases (13.5%) and RUQ in 1 case (7%). We think that CT is an useful diagnostic method of periappendiceal abscesses especially when clinical findings are atypical

352

Hyperfunctioning parathyroid adenoma - radiological findings  

International Nuclear Information System (INIS)

Interest in increasing in the use of imaging methods during the preoperative investigation of patients with primary hyperparathyroidism. The authors report a case of hyper functioning adenoma of the parathyroid that emerged with skeletal manifestation where ultrasonography and scintigraphy were employed with Tc-99m sestamibi in the preoperative study of the parathyroids. In addition, radiologic finding, utilizing conventional radiology and computerized tomography, and the evolutive aspect of the lesions, four months after the beginning of the treatment, are also presented. (author)

353

Unhappiness and job finding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

It is puzzling that people feel quite unhappy when they become unemployed, while at the same time active labor market policies are needed to bring unemployed back to work more quickly. Using data from the German Socio-Economic Panel, we investigate whether there is indeed such a puzzle. First, we find that nearly half of the unemployed do not experience a drop in happiness, which might explain why at least some workers need to be activated. In addition to that, we find that even though unempl...

Gielen, Anne C.; Ours, Jan C.

2012-01-01

354

Computing travel time when the exact address is unknown: a comparison of point and polygon ZIP code approximation methods  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Travel time is an important metric of geographic access to health care. We compared strategies of estimating travel times when only subject ZIP code data were available. Results Using simulated data from New Hampshire and Arizona, we estimated travel times to nearest cancer centers by using: 1 geometric centroid of ZIP code polygons as origins, 2 population centroids as origin, 3 service area rings around each cancer center, assigning subjects to rings by assuming they are evenly distributed within their ZIP code, 4 service area rings around each center, assuming the subjects follow the population distribution within the ZIP code. We used travel times based on street addresses as true values to validate estimates. Population-based methods have smaller errors than geometry-based methods. Within categories (geometry or population, centroid and service area methods have similar errors. Errors are smaller in urban areas than in rural areas. Conclusion Population-based methods are superior to the geometry-based methods, with the population centroid method appearing to be the best choice for estimating travel time. Estimates in rural areas are less reliable.

Berke Ethan M

2009-04-01

355

Infecção pelo Papilomavírus Humano em Adolescentes: Relação com o Método Anticoncepcional, Gravidez, Fumo e Achados Citológicos Human Papillomavirus Infection in Adolescents: Relation to Contraceptive Method, Pregnancy, Smoking, and Cytologic Findings  

Directory of Open Access Journals (Sweden)

Full Text Available Objetivo: avaliar a influência da gravidez, do hábito de fumar, do método anticoncepcional e quais os achados citológicos mais freqüentes em adolescentes com infecção pelo HPV. Métodos: foram analisadas retrospectivamente 54.985 citologias de pacientes atendidas entre julho de 1993 e dezembro de 1998. Deste total, 6.498 exames (11,8% eram de pacientes com idade inferior a 20 anos, sendo que 326 (5,9% apresentavam sinais citológicos de infecção por HPV, associada ou não a neoplasia intra-epitelial cervical (NIC grau I. O grupo controle foi composto por 333 pacientes na mesma faixa etária, sem sinais citológicos de infecção por HPV. Resultados: a infecção pelo HPV foi mais freqüente nas adolescentes que fazem uso de anticoncepcionais orais (16,9% versus 13,8%, pPurpose: to evaluate the influence of pregnancy, habit of smoking, and the contraceptive method in HPV infection and the frequency of cytologic findings in adolescent women with HPV infection. Methods: a total of 54,985 cytologic examinations of patients seen between July, 1993 and December, 1998 were retrospectively analyzed. Of this total, 6,498 (11.8% examinations were from patients under 20 years old. Of the total of 6,498 cytologic examinations, 326 (5.9% presented signs of HPV infection, with or without grade I cervical intraepithelial neoplasia (CIN. Patients with diagnosis of grade II and III CIN were excluded. The control group consisted of 333 patients paired by age, without cytological signs of HPV infection. Results: in adolescents, HPV infection was more frequent in oral contraceptive users (16.9% versus 13.8%, p<0.01 and in those who presented with clue cells in cytologic smears (22.4% versus 14.7%, p<0.001. The frequency of HPV infection in couples who used condom was 0% versus 2.1% in the control group (p<0.01. The difference in the number of pregnant women (41.1% versus 44.1% and smokers (21.8% versus 16.5% was not statistically significant. Conclusions: HPV infection is more frequent in adolescent women in use of oral contraceptive and with clue cells as cytologic finding. HPV infection did not occur in couples who used condom. Gestation and the habit of smoking did not influence the incidence of HPV infection.

Eddie Fernando Candido Murta

2001-05-01

356

Helium leak finding plant  

International Nuclear Information System (INIS)

The invention concerns a helium leak finding plant with a mass spectrometer cell on the suction side of a molecular pump and a mechanical pre-pump, where a test sample or a test sensor is connected between the two pumps. The mechanical pre-pump consists of three successive stages. (orig./HP)

357

Tooth Tutoring: The Findings.  

Science.gov (United States)

Findings are reported on a three year cross-age tutoring program in which undergraduate dental hygiene students and college students from other disciplines trained upper elementary students to tutor younger students in the techniques of dental hygiene. Data includes pre-post scores on the Oral Hygiene Index of plaque for both experimental and…

Cone, Richard; And Others

358

Neuroblastoma: computed tomographic findings  

International Nuclear Information System (INIS)

To evaluate the characteristic CT findings of neuroblastoma, we studied neuroblastomas. We analysed CT findings of available 25 cases among pathologically proved 51 neuroblastomas from Jan. 1983 to Sept. 1990. The most frequent site of origin is adrenal gland (40%) and the second is retroperitoneum (32%) and the third ismediastinum (16%). Characteristic CT findings are as follows: Calcifications within the tumor is detected in 86% of abdominal neuroblastomas and 50% of mediastinal origin. Hemorrhagic and necrotic changes within the tumor is noted at 86% in the tumor of abdominal origin and 25% in mediastinal neuroblastomas. Contrast enhanced study showed frequently seperated enhanced appearance with/without solid contrast enhancement. Encasements of major great vessels such as aorta and IVC with/without displacement by metastatic lymph nodes or tumor are frequently seen in 90% of abdominal neuroblastomas. Multiple lymphadenopathy are detected in 95% of abdominal neuroblastomas and 25% of mediastinal neuroblastomas. The most common organ or contiguous direct invasion is kidney in 6 cases and the next one is liver but intraspinal canal invasion is also noted in 2 cases. We concluded that diagnosis of neuroblastoma would be easily obtained in masses of pediatric group from recognition of above characteristic findings

359

[Incidental radiological findings].  

Science.gov (United States)

All findings which arise in the context of radiological diagnostics, potentially affect the health of a subject but with no intention to detect the corresponding finding are considered to be incidental radiological findings (IF). The prevalence of IFs is increasing due to the wider use of modern imaging techniques, such as magnetic resonance imaging (MRI) and computed tomography (CT) in routine clinical practice and the inclusion of imaging, such as whole body MRI in large population-based cohorts. The reporting of radiological IFs can lead to further diagnostics and treatment. The management of IFs in the clinical routine is regulated by the guidelines of the various academic societies. The management of IFs in the setting of research studies differs depending on various factors, such as study design and health status of enrolled subjects. In general, IFs must be disclosed to the subject if the radiological IFs are potentially clinically relevant; however, subjects must also be protected from the consequences of false positive findings. This review article discusses radiological IFs in the setting of the clinical routine and research studies and provides a basic summary of the management recommendations for commonly occurring IFs. PMID:25099387

Weckbach, S; Schlett, C L; Bertheau, R C; Kauczor, H-U

2014-09-01

360

Radiological findings in NAO syndrome  

International Nuclear Information System (INIS)

Background: Diseases exhibiting osteolysis in children are rare hereditary conditions. Several types have been recognised with different clinical manifestations. One type includes subcutaneous nodules, arthropathy and osteolysis and has been termed NAO syndrome. Previous radiological reports have described the affected bones, usually the carpal and tarsal regions, but a detailed analysis of the radiological findings of both the axial as well as the appendicular skeleton has not been reported. Objectives: To describe the radiological findings in a large group of children with an autosomal recessive disease characterized by nodules, familial arthropathy and osteolysis. Materials and methods: The study comprises 14 patients from 9 families and all patients had the triad of nodulosis, arthropathy and osteolysis (NAO). Results: The most common radiological manifestations were osteopenia, undertubulation of long bones, arthritic changes, sclerotic sutures of the calvaria, osteolysis and muscle contractures. Other common findings were squared vertebrae, broad medial clavicles and brachycephaly. Progress of disease was documented in more than half of the patients. Conclusions: Our study is the first report of the detailed radiological findings of NAO syndrome. In NAO syndrome, both the axial and appendicular skeleton are involved (orig.)

 
 
 
 
361

Neuroradiological findings in Behcet's disease  

International Nuclear Information System (INIS)

Purpose: We present the typical neuroradiological findings in three patients with neuro-Behcet in comparison with a review of neuroradiological and histopathological findings described in the literature. Material and Methods: In three male patients aged 32-57 years with Behcet's disease and neurological symptoms cranial CT and MRI studies were carried out. Findings were monitored over a period of 6-18 months. Additionally, cerebral and renal DSA were performed in two patients. Results: In two patients we found acute inflammatory lesions located in the brainstem and the periventricular white matter, some of which were associated with an acute inflammatory disruption of the blood-brain barrier. Lesions decreased in size under treatment, but complete resolution was not consistently noted. In the third patient we found a thrombosis of the superior sagittal sinus but no other intracranial abnormalities. Conclusions: Our findings agree with those described in the literature as being typical of Behcet's disease. Inflammatory lesions most commonly occur in the brain stem, followed by the basal ganglia and the cortex and white matter of both the cerebrum and cerebellum. In contrast to venous sinus thrombosis, brainstem atrophy and cortical or cerebellar lesions, white matter lesions have little diagnostic value, irrespective of their location. The definitive diagnosis of Behcet's disease is made on the basis of clinical criteria. (orig.)

362

Find Arc Degree Measures  

Science.gov (United States)

This unit will introduce central angles, arcs of circles, congruent circles, and congruent arcs. Note taking time! Find the definition of a central angle, minor arc, major arc,semicircle, measure of a minor arc, and measure of a major arc from page 659 of your text from Class Zone: Class Zone Geometry Textbook Check your answers in the following links: Angles in Circles Arcs in Circles Now take notes from page 660 in your text from Class Zone ...

Neubert, Mrs.

2011-03-08

363

Finding Monster Waves  

Science.gov (United States)

In this lesson, students learn about the varying sizes of ocean waves, what causes such variation, and where to find giant waves. Students will learn the parts of a wave, and discuss wave height, wavelength, and wave period. They will explore variables that influence wave size through scientific visualizations. They will then experiment with creating waves on the National Geographic Wave Simulator and discuss how geography affects waves.

364

Heterotopic pregnancy: Sonographic findings  

Energy Technology Data Exchange (ETDEWEB)

To evaluate the sonographic findings of the heterotopic pregnancy which is increasing recently. Thirty-nine cases of heterotopic pregnancy after ovulation induction and IVF-ET (In Vitro Fertilization-Embryo Transfer) during the recent 3 years were analyzed. They were diagnosed by ultrasonography and proved surgically afterwards. Sonographic findings were analyzed focusing on gestational week of intrauterine pregnancy and location of ectopic pregnancy. In particular, adnexal mass was evaluated with regard to size and the characteristic findings such as ectopic gestational sac (echogenic ring). Also, overian cyst and fluid collection in cul-de-sac space were reviewed carefully. Heterotopic pregnancy was proved surgically by salpingectomy in 33 cases and by resection of cornus in six cases. Sonographic diagnosis using transvaginal ultrasound was made from five weeks to nine weeks two days (six weeks and four days in average) from last menstral period in all 39 cases. Ectopic pregnancy was identified in ampullary part in 29 cases, in the isthmic portion of tube in four cases and in the cornus of uterus in six cases. The intrauterine pregnancy was diagnosed by identifying the intrauterine gestational saccontaining a yolk sac in seven cases and the embryo with fetal heart beat in the remaining 32 cases. Adnexal masses of heterotopic pregnancy were less than 3 cm in diameter in 2 cases (57%), 3-4 cm in 11 cases (28%) and more than 4 cm in 6 cases (15%). A characteristic finding of ectopic mass was echogenic ring which was visible in 33 (84.6%) cases by transvaginal ultrasound. Six cases had pelvic hematosalpinx and two had pelvic hematoma. Of 10 cases (26%) which were identified to have ovarian hyperstimulation syndrome, eight (21%) had large amount of fluid collection in cul-de-sac and abdomen. Ultrasonographic identification of the intrauterine pregnancy and the ectopic chorion ring is effective for the early diagnosis of the heterotopic pregnancy.

Kwon, Tae Hee [CHA General Hospital of Seoul, Pochon CHA University College of Medicine, Seoul (Korea, Republic of)

1999-03-15

365

CT findings in melioidosis  

International Nuclear Information System (INIS)

Computed Tomography findings in 5 patients with melioidosis are presented. Lung lesions consisted of upper lobe infiltration with a small thin-walled cavity in 2 cases and lower lobe consolidation without cavity in another case. Pleural lesions may be seen as a small pleural nodule, effusion with associated lung lesion, hydropneumothorax as a complication or the end stage fibrothorax due to chronic empyema thoracis. In one case hepatosplenic microabscesses were observed. 13 refs., 7 figs

366

MELAS syndrome: neuroradiological findings  

International Nuclear Information System (INIS)

To assess the computed tomography (CT) and magnetic resonance (MR) findings in MELAS syndrome (mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes) and their contribution to the diagnosis of this entity. We present three patients in which a diagnosis of MELAS syndrome was confirmed by muscle biopsy. CT revealed pathological findings in two patients: bilateral calcifications in the basal nuclei in one and low-attenuation lesions in occipital lobes in the other. Initial or follow-up MR demonstrated pathological findings highly suggestive of MELAS syndrome in all the patients. They consisted of hyperintense lesions in T2-weighted images, located predominantly in the cortex of occipital and parietal lobes. Cerebellar atrophy was also observed in two patients. The clinical signs varied, but epileptic seizures, headache, vomiting, ataxia, muscle weakness and pyramidal involvement were among the major ones. Only one patient presented high lactic acid levels, and in two, the initial muscle biopsy was not conclusive enough to provide the definitive diagnosis. CT and, especially, MR are useful tools in the diagnosis of MELAS syndrome, particularly in those cases in which initial negative laboratory and histological results make diagnosis difficult. (Author) 21 refs

367

CT findings of slilcosis  

Energy Technology Data Exchange (ETDEWEB)

To describe chest radiographic and CT findings of silicosis, and to compare their findings. Ten coal miners and six stonemasons were included in this study. All were male and their mean age was 53.1. The mean duration of dust exposure was 15.2 years(range, 5-30 years) in coal miners and 25.3 years(range, 15-35 years) in stonemasons. Chest radiographs(n=16), conventional CT scans(n=4), and high resolution CT(HRCT) scans(n=13) were evaluated. Parenchymal abnormalities were interpreted on the basis of ILO standard films(1980) in chest radiographs and on the basis of CAP(College of American Pathologists, 1979) in CT(HRCT) films. Chest radiographs revealed large opacities(n=8), small opacities(n=6), and normal findings(n=2). Type r(n=4) and category 1/1(n=2) were most common for small opacities, while for large opacities, category B(n=4) and category c(n=4) were most common. These small and large opacities were located predominantly in the area of the upper and middle lung. Associated findings were emphysema(n=7), eggshell nodal calcifications(n=3), pneumothorax(n=3), C-P angle blunting(n=4), and pleural thickening(n=1). CT scans revealed micronodules(n=16), nodules(n=3), and progressive massive fibrosis(PMF, n=8). All these lesions were located in the upper and middle lungs, especially in the central portion of the posterior lung. PMF showed diffuse and homogenous(n=3) and puntate(n=2) calcifications, cavitations(n=5), air bronchograms(n=3), and necrosis(n=1). Peripheral paracicatrical emphysema was associated with PMF(n=8). Other findings were pneumothorax(n=4), emphysema(n=10), hilar and mediastinal nodal enlargement(n=11) bronchial wall thick- enings(n=6), bronchiectasis(n=1), pleural thickening(n=7), parenchymal fibrosis(n=1), and pulmonary tuberculosis(n=2). Small and large opacities in chest radiographs and micronodules, nodules, and PMFs in CT (HRCT) films were located predominately in the upper and middle lungs, especially in the central portion of the posterior lung in CT films. CT was superior to plain chest radiographs in the following ways : (1) in the early detection of small opacities, including subpleural micronodules, and in the precise evaluation of their concen-tration and topography ; (2) in the detection of cavitation or calcification within conglomerate large opacity lesions ; (3) in the detection of hilar and mediastinal nodal enlargements ; and (4) in quantitative assessment of the severity of emphysema.

Jung, Dong Hee; Kim, Kun Il; Son, Hyun Ju; Ro, Young Jin; Jung, Doo Young; Park, Jae Yeong; Lee, Jun Woo; Kim, Byung Soo [Pusan National Univ. College of Medicine, Pusan (Korea, Republic of)

1996-04-01

368

CT findings of mesenteric lymphangioma  

International Nuclear Information System (INIS)

Purpose: To study the CT findings of mesenteric lymphangioma (ML). Materials and methods: The CT findings of ML in five cases (8?40 years old, all male with average age of 29 years) proved by pathology were analyzed. Results: There were one case of solitary cyst and four cases of multiple cysts or (and) multi-loculated cysts. All had thin smooth wall and homogeneous density, and mesenteric vessels were seen in the cysts in three of the five cases. Four cases originated from small bowel mesentery, while one case was from colon mesentery. Conclusion: ML often manifests as huge multi-loculated thin wall cyst frequently originating from small mesentery. The presence mesenteric vessels in the cyst was pathognomonic of this disease

369

Find a Genetic Counselor  

Science.gov (United States)

... be of benefit to you. Longer consultations by phone are usually not possible. A scheduled appointment would be necessary to discuss your concerns. Each center varies with regard to referral requirements, payment methods, and services. Disclaimer of Warranties and Liabilities ...

370

MR findings of ulegyria  

International Nuclear Information System (INIS)

Magnetic resonance (MR) findings of the brains diagnosed to have ulegyria were reviewed. The reviewed subjects comprised six epileptic children, ranged from 2 to 16 years of age. All patients had convulsion of tonic-clonic type of various severity and had histories of ischemic-hypoxic or hypoglycemic episode in the perinatal or postnatal period. T1-weighted images demonstrated the findings precisely reflecting the salient macroscopic features of ulegyria; localized atrophy of the brain with mushroom-shaped cortical gyri with narrow roots and relatively spared wider crowns. T2-weighted images showed the areas of hyperintensity in the subcortical and deep white matter subjacent to the atrophic cortex, suggestive of cicatrical gliosis as well as cystic degeneration. The atrophic gyri were seen in the anterior and/or posterior parasagittal arterial border zones bilaterally with minimal asymmetry. Although these findings were nearly pathognomonic to ulegyria, polymicrogyria could mimic it since both are characterized by abnormally diminutive cortical gyri seen in epileptic children. In polymicrogyria, however, affected gyri are uniformly diminutive and not mushroom-shaped, the cortex is rather thickened than atrophic, the underlying white matter shows no focal hyperintensity, subcortical cystic changes are not present, and affected cortex is not restricted to arterial border zones. Even in one of our cases with extensive ulegyria, it was easy to differentiate it from polymicrogyria since parasagittal regions were most severely affected. Although the previous reports on ulegyria have been exclusively based on postmortem pathological examinations or experimental models, its easy recognition on MRI would contribute to further understanding of its clinical significance and mechanisms. (author)

371

MR findings of ulegyria  

Energy Technology Data Exchange (ETDEWEB)

Magnetic resonance (MR) findings of the brains diagnosed to have ulegyria were reviewed. The reviewed subjects comprised six epileptic children, ranged from 2 to 16 years of age. All patients had convulsion of tonic-clonic type of various severity and had histories of ischemic-hypoxic or hypoglycemic episode in the perinatal or postnatal period. T{sub 1}-weighted images demonstrated the findings precisely reflecting the salient macroscopic features of ulegyria; localized atrophy of the brain with mushroom-shaped cortical gyri with narrow roots and relatively spared wider crowns. T{sub 2}-weighted images showed the areas of hyperintensity in the subcortical and deep white matter subjacent to the atrophic cortex, suggestive of cicatrical gliosis as well as cystic degeneration. The atrophic gyri were seen in the anterior and/or posterior parasagittal arterial border zones bilaterally with minimal asymmetry. Although these findings were nearly pathognomonic to ulegyria, polymicrogyria could mimic it since both are characterized by abnormally diminutive cortical gyri seen in epileptic children. In polymicrogyria, however, affected gyri are uniformly diminutive and not mushroom-shaped, the cortex is rather thickened than atrophic, the underlying white matter shows no focal hyperintensity, subcortical cystic changes are not present, and affected cortex is not restricted to arterial border zones. Even in one of our cases with extensive ulegyria, it was easy to differentiate it from polymicrogyria since parasagittal regions were most severely affected. Although the previous reports on ulegyria have been exclusively based on postmortem pathological examinations or experimental models, its easy recognition on MRI would contribute to further understanding of its clinical significance and mechanisms. (author).

Momoshima, Suketaka; Shiga, Hayao; Yuasa, Yuji; Imai, Yutaka; Higuchi, Nobuya (Keio Univ., Tokyo (Japan). School of Medicine); Maezawa, Mariko

1991-08-01

372

CT findings of hypersensitivity pneumonitis  

International Nuclear Information System (INIS)

CT findings of 22 cases of hypersensitivity pneumonitis (HP) were evaluated on 1 cm slices. All cases were diagnosed by transbronchial lung biopsy and clinical information. The study population included 8 men and 14 women with a mean age of 43 years. The causative antigens were considered to be so-called summer type in 17 cases, air humidifier in 1, pigeon in 1 and paint spray (isocyanate was suspected) in 3. CT examinations were performed at a mean of 1.5 weeks after admission. In conclusion, characteristic CT findings of HP include combination of small nodular shadows and slight elevation of lung density. The size of nodular shadows was usually within 1 cm diameter, and their distribution was considered to be a centrilobular pattern, representing alveolitis and granuloma formation in a secondary lobule. It was thought that the slight elevation of lung density developed when the disease extended all over the secondary lobule and the nodules developed when the disease was limited to the centrilobular lesion. In most cases, significant changes in proximal bronchi and pulmonary vasculatures could not be detected. The presence of segmental or lobar distribution of the shadows was also suggested. In addition to the typical findings, various other findings were also revealed; irregular shaped dense shadows, subpleural curvilinear shadow and honeycombing formation, especially in chronic cases. These findings have caused some difficulty in distinguishing HP from other interstitial diseases. More precise information can probalty be obtained by thin slice CT than by 1 cm slice thicknesses, nevertheless, the standard method of CT should yield a useful diagnostic imaging. (author)

373

Spleen findings in drowning  

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A retrospective study of spleen findings in 42 victims of drowning and a comparison group of 42 cases of asphyxiation due to other causes (hanging, ligature strangulation and manual strangulation), that were matched for sex, age, body weight and build, was performed. Significantly smaller spleen weights (P < 0.05), spleen weight:body weight ratios (P < 0.01) and spleen weight:liver weight ratios (P < 0.01) were found in the victims of drowning. The difference in weight was 18%. A significant...

Haffner, H. Th; Graw, Matthias; Erdelkamp, J.

1994-01-01

374

Angiomatoid fibrohistiocytoma - radiological findings  

International Nuclear Information System (INIS)

The authors report a case of an 11-year-old girl with asthenia, anemia and right supraclavicular tumor. The chest roentgenogram and computed tomography showed a heterogeneous soft tissue mass with peripheral calcifications, beside the scapula. The histologic diagnosis after surgery was an angiomatoid fibrous histiocytoma. This rare type of tumor tend to occur in young adults and have a borderline feature, and it is described in the literature as a low-grade, malignant fibrous histiocytoma. the authors describe its radiological and histological findings. (author)

375

Sialoblastoma: MRI findings  

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Sialoblastoma is a rare, aggressive and potentially malignant salivary gland tumour diagnosed in the neonatal period. A total of 28 cases have been reported in the literature, but reports of the imaging findings are limited. We describe a neonate with a right parotid sialoblastoma. MRI showed a large facial mass, which was mostly hypointense to the brain on T1-weighted images and mildly hyperintense on T2-weighted images. There were foci of haemorrhage and necrosis. Heterogeneous and weak contrast enhancement was detected on contrast-enhanced images. The tumour invaded the maxilla and adjacent muscles. (orig.)

Yekeler, Ensar; Dursun, Memduh; Ucar, Adem; Genchellac, Hakan; Acunas, Gulden [Istanbul Faculty of Medicine, Department of Radiology, Istanbul (Turkey); Gun, Feryal; Kilincaslan, Huseyin [Istanbul Faculty of Medicine, Department of Paediatric Surgery, Istanbul (Turkey)

2004-12-01

376

Find-It! Consumer  

Science.gov (United States)

From the Washington State Library, Find-It! Consumer provides links to and information about over 100 consumer safety and protection Websites. Annotated Websites concerning Washington State or the entire United States may be searched by keyword or browsed by topic. The librarians have included a wonderful section on Top Searches, which gives guides to information and resources on a broad range of subjects, from insecticide in food to choosing an Internet service provider. Up-to-date recalls and new consumer information are also highlighted.

377

Ultrasonographic findings of Epicondylitis  

International Nuclear Information System (INIS)

To evaluate the usefulness of ultrasonographic findings of the common extensor and flexor tendon in evaluation of patients with lateral and medial epicondylitis. Thirty eight elbows from twenty four patients (mean age=45.2 years) were included. Ultrasonographic examination was performed to evaluate lateral or medial epicondylitis. Epicondylitis was divided into five groups according to the severity of disease: 1) normal, 2) tendinopathy, 3) tendinopathy with a partial tear, partial tear and 4) complete tear. Change in the size of a tendon, bony change of the epicondylitis, presence or absence of calcification or echogenic foci in the common tendon and hypervascularity for each categories were also assessed. In addition, these lesions were divided into the superficial and deep according to the location of lesions. According to the severity, there were 15 cases of normal, 13 tendinopathies, 8 tendinopathies with a partial tear, 2 partial tears and 0 complete tear. Bony change was seen only in tendinopathy, tendinopathy with partial tear and partial tear. Calcification or echogenic foci were only observed in cases with tendinopathy and tendinopathy with partial tear. Hypervascularity was only seen in one case of tendinopathy. With thorough understanding of ultrasonographic findings of epicondylitis, ultrasonographic examination can be especially useful and effective in evaluating the severity and location of lesions.

378

Ultrasonographic findings of Epicondylitis  

Energy Technology Data Exchange (ETDEWEB)

To evaluate the usefulness of ultrasonographic findings of the common extensor and flexor tendon in evaluation of patients with lateral and medial epicondylitis. Thirty eight elbows from twenty four patients (mean age=45.2 years) were included. Ultrasonographic examination was performed to evaluate lateral or medial epicondylitis. Epicondylitis was divided into five groups according to the severity of disease: 1) normal, 2) tendinopathy, 3) tendinopathy with a partial tear, partial tear and 4) complete tear. Change in the size of a tendon, bony change of the epicondylitis, presence or absence of calcification or echogenic foci in the common tendon and hypervascularity for each categories were also assessed. In addition, these lesions were divided into the superficial and deep according to the location of lesions. According to the severity, there were 15 cases of normal, 13 tendinopathies, 8 tendinopathies with a partial tear, 2 partial tears and 0 complete tear. Bony change was seen only in tendinopathy, tendinopathy with partial tear and partial tear. Calcification or echogenic foci were only observed in cases with tendinopathy and tendinopathy with partial tear. Hypervascularity was only seen in one case of tendinopathy. With thorough understanding of ultrasonographic findings of epicondylitis, ultrasonographic examination can be especially useful and effective in evaluating the severity and location of lesions.

Kwak, Seo Hyun; Song, In Sup; Lee, Jong Beum; Lee, Hwa Yeon; Yoo, Seung Min; Yang, Seong Jun [Yong San Hospital, Chung-Ang University College of Medicine, Seoul (Korea, Republic of); Seo, Kyung Mook [Chung-Ang University College of Medicine, Seoul (Korea, Republic of)

2002-09-15

379

Climate change: Recent findings  

International Nuclear Information System (INIS)

In the late eighties several reports have been published on climate change and sea level rise. In the meantime insights may have changed due to the availability of better and more observations and/or more advanced climate models. The aim of this report is to present the most recent findings with respect to climate change, in particular of sea level rise, storm surges and river peak flows. These climate factors are important for the safety of low-lying areas with respect to coastal erosion and flooding. In the first chapters a short review is presented of a few of the eighties reports. Furthermore, the predictions by state of the art climate models at that time are given. The reports from the eighties should be considered as 'old' information, whereas the IPCC supplement and work, for example, by Wigley should be considered as new information. To assess the latest findings two experts in this field were interviewed: dr J. Oerlemans and dr C.J.E. Schuurmans, a climate expert from the Royal Netherlands Meteorological Institute (KNMI). Their views are presented together with results published in recent papers on the subject. On the basis of this assessment, the report presents current knowledge regarding predictions of climate change (including sea-level rise) over the next century, together with an assessment of the uncertainties associated with these predictions. 14 figs., 11 tabs., 24 refs

380

Renal dysplasia: US findings  

International Nuclear Information System (INIS)

Renal dysplasia is a congenital anomaly with abnormal development of nephrotic and ductal structure and untreatable disease with absent renal function. To determine whether any consistent sonographic patterns exists,the sonograms of 27 pediatric patients with mastocytosis despotically kidney were reviewed. The diagnosis was proved by pathology in 16 cases and other radiologic imaging in 11 cases. In the classical multicystic despotically kidney(pelvoinfundibular atresia type, 10 cases), there were typical findings, such as absent communication between peripherally located variable sized cysts and presence of the largest cyst away from the renal hilum. One case was associated contralateral renal hydronephrosis. There cases were hydro nephrotic type which had medial location of the largest cyst with non communicating peripheral cysts. Segmental dysplasia with double collecting system and ureterocele (5 cases) and dysplasia due to parasite urethral valve (2 cases) showed hydronephrosis without identifiable peripheral cysts. Among the hypoplastic dysplastic kidney (7 cases) including ectopic kidneys (3cases), corticomedullary differentiation were hard to be identified in 2 cases. In conclusion, diagnosis of the renal dysplasia can be obtained by US only or US with other functional studies such as radionuclide scan(99mTc-DMSA or renogram) and IVP. US detection of renal dysplasia is easy, and US findings provide valuable information in the subsequent management

 
 
 
 
381

Brain venous pathologies: MRI findings  

International Nuclear Information System (INIS)

Purpose: To describe MRI findings of the different brain venous pathologies. Material and Methods: Between January 2002 and March 2004, 18 patients were studied 10 males and 8 females between 6 and 63 years old; with different brain venous pathologies. In all cases brain MRI were performed including morphological sequences with and without gadolinium injection and angiographic venous sequences. Results: 10 venous occlusions were found, 6 venous angiomas, and 2 presented varices secondary to arteriovenous dural fistula. Conclusion: Brain venous pathologies can appear in many different clinical contexts, with different prognosis and treatment. In all the cases brain MRI was the best imaging study to disclose typical morphologic abnormalities. (author)

382

CT findings of invasive pulmonary aspergillosis  

International Nuclear Information System (INIS)

Objective: To study the CT findings of IPA. Methods: CT scans were performed in eight cases aged 25-76 years with pathologically proved IPA, two cases underwent second CT after 4 weeks. Results: CT findings includes mass-like infiltrate (n = 3), consolidation (n = 3); multi-nodules (n = 2). Conclusions: Early CT findings of IPA consist of mass-like, consolidation or multi-nodules, the CT halo sign: strongly suggests early diagnosis of IPA

383

Radiologic findings in neurofibromatosis  

International Nuclear Information System (INIS)

Neurofibromatosis is an uncommon but certainly not a rare hereditary disorder, probably of neuralcrest origin, involving not only neuroectoderm and mesoderm but also endoderm and characterized by cafe au lait spots and cutaneous and subcutaneous tumors, with secondary mesodermal defects responsible for protean osseous abnormalities and various manifestations in other systems. This paper is a study of confirmed 143 cases of neurofibromatosis collected for past 8 years. In this analysis, special attention was given to the selected 37 cases which showed abnormal findings on radiological examinations. Overall male to female ratio was 1 : 1.3. The most frequent kind of abnormalities was vertebral kyphoscoliosis in 12 cases. Among the more pathognomonic but uncommon abnormalities to neurofibromatosis, we experienced each 2 cases of lambdoid defect, pseudoarthrosis and renovascular hypertension, and 1 cases of sphenoid bone absence.

384

Radiologic findings in neurofibromatosis  

Energy Technology Data Exchange (ETDEWEB)

Neurofibromatosis is an uncommon but certainly not a rare hereditary disorder, probably of neuralcrest origin, involving not only neuroectoderm and mesoderm but also endoderm and characterized by cafe au lait spots and cutaneous and subcutaneous tumors, with secondary mesodermal defects responsible for protean osseous abnormalities and various manifestations in other systems. This paper is a study of confirmed 143 cases of neurofibromatosis collected for past 8 years. In this analysis, special attention was given to the selected 37 cases which showed abnormal findings on radiological examinations. Overall male to female ratio was 1 : 1.3. The most frequent kind of abnormalities was vertebral kyphoscoliosis in 12 cases. Among the more pathognomonic but uncommon abnormalities to neurofibromatosis, we experienced each 2 cases of lambdoid defect, pseudoarthrosis and renovascular hypertension, and 1 cases of sphenoid bone absence.

Kim, Dai Young; Jeon, Seok Chol; Lee, Kwan Se; Yeon, Kyung Mo; Choo, Dong Woon [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1979-12-15

385

Ultrasonographic findings of retinoblastoma  

International Nuclear Information System (INIS)

Retinoblastoma is the most common intraocular tumor in infants and young children which has relatively favorable prognosis with early diagnosis and adequate treatment, however, it can be lethal if the treatment is delayed or inadequate. Clinically, early diagnosis is often difficult because of minimal subjective and objective signs and symptoms, and the patients are usually too young to complain visual disturbance. When ophthalmoscopicexamination is impossible due to presence of opaue media in front of tumor mass as associated inflammatory reaction, hemorrhage, corneal opacity, retinal detachment, etc, ultrasonography is necessary for diagnosis of retinoblastoma. Authors analyzed ultrasonographic al findings with pathological correlation on 10 cases of confirmed retinoblastoma during the period of March 1981 to September1982 at the Seoul National University Hospital. In all cases, ultrasonography demonstrates intraocular masses and all of which are cystic type.Reflectivity of masses are higher than retroorbital fat tissue in 8 cases, and 7 cases show irregular internal echogenic texture. There is no correlation between reflexivity and internal echogenic texture with microscopic findings as rosette, pseudo rosette and micro cysts. Calcifications are demonstrated by ultrasonography as strong reflectiveness with posterior sonic shadowing in 9 cases and 9 of 10 cases are well correlated with calcifications in pathologic specimens. Anechoic cystic areas are shown in 9 case Anechoic cystic areas are shown in 9 cases, and 6 of 10 cases are well correlated with necrosis in pathologic specimen. In all cases, there is no attenuation of sound within tumor masses, and no demonstrable choroidal excavation. Associated retinal detachment is hardly identifiable in irregular contour and internal texture of cystic tumor masses

386

Radiologic findings of dwarfism  

Energy Technology Data Exchange (ETDEWEB)

The stature of human is very important factor in human-being, especially in childhood. The stature depends on various different conditions, such as familial factor, constitutional factor, chromosomal anomalies, skeletal disorders, or endocrinopathies. The early diagnosis of dwarfism is very important problem, because if appropriate treatment is delayed, the complication or sequales are more increased. The survey of familial history or patient's past history, detail check up of physical examination, radiological evaluation, and other laboratory examinations are essentially needed for the accurate diagnosis of dwarfism. Among the patients admitted to Yonsei University college of Medicine, Severance Hospital since 1963, with chief complaint of short stature or other associated diseases, an analysis of radiological findings were made for the 72 cases of chromosomal anomalies, skeletal dysplasia, and cretinism in which radiologic evaluation was available. The conclusions are as follows; 1. The cause of short stature are chromosomal anomalies (48 cases), skeletal dysplasia (14 cases) and cretinism (10 cases). 2. in chromosomal anomalies, 43 cases of mongolism and 5 cease of Turner's syndrome are noted. In mongolism, 18 cases among the 30 cases below 1 year old are distributed below the 10 percentile of height. On radiologic findings, 11 paired ribs (22/43), congenital heart disease (14/43), decreased iliac index (8/12), and associated anomalies or diseases, such as pneumonia (14 cases), C1-C2 dislocation (1 case), imperforated anus (1 case), Morgagni's hernia (1 case) and leukemia with sepsis (1 case). In Turner's syndrome, decreased bone density (5/5), positive metacarpal sign (2/5), positive carpal sign (1/5), change of knee joint (3/5), hypoplasia of (1/3), and increased carrying angle of elbows (1/3) are noted.

Hwang, M. S.; Oh, K. K.; Park, C. Y.; Kim, D. H. [Yonsei University, College of Medicine, Seoul (Korea, Republic of); Kim, D. H. [Yonsei Univ., Seoul (Korea, Republic of)

1981-06-15

387

Tomographic and pathological findings in pulmonary sarcoidosis  

Energy Technology Data Exchange (ETDEWEB)

Objective: To analyze radiological findings observed at high-resolution computed tomography in patients with sarcoidosis, and establishing their correlation with pathological findings. Materials and Methods: High-resolution computed tomography findings in ten patients with sarcoidosis were reviewed and correlated with findings in specimens obtained by surgical biopsy or at necropsy of four of such patients. Results: The most frequently observed finding was presence of nodules with perilymphatic distribution, predominating along bronchovascular sheaths and pleural surface, with subpleural nodules and nodular scissurae. Other less frequent findings were ground-glass attenuation and interlobular septa thickening. Conclusion: In general, all the mentioned findings demonstrated anatomopathological correlation with development of granulomas in these regions. (author)

Melo, Alessandro Severo Alves de; Marchiori, Edson [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. of Radiology; Capone, Domenico [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Dept. of Pneumology

2011-07-15

388

Ultrasonographic and CT findings of the mesothelioma  

International Nuclear Information System (INIS)

Ultrasonographic and CT findings were reported in a 63 year-old female with a localized mesothelioma and in a 79 year-old male with a malignant mesothelioma. CT and ultrasonographic findings were not pathognomonic but both methods were very effective to elucidate the solid nature and extent of the tumor. (author)

389

Ultrasonographic findings of acute appendicitis  

International Nuclear Information System (INIS)

For the evaluation of acute appendicitis, many diagnostic methods, such as physical examination, laboratory findings, plain abdomen and barium enema have been widely used. But the overall accuracy was ranged from 50% to 84% and negative appendectomy rate was reported between 5% and 35%. In these days, high resolution ultrasonography is well known to be a good imaging modality in evaluation of acute appendicitis and its complications. Using high resolution ultrasonography, 138 patients with right lower quadrant abdominal pain were examined for 16 months. The results were compared to post-operative findings and clinical follow up study. The results were as follows: 1. The sex distribution of cases were 58 males and 80 females, and most common in the third decade (33.3%). 2. The positive ultrasonographic findings were in 69 cases (50%), those were simple appendicitis without complication in 46 cases (66.7%), acute appendicitis with periappendicitis in 9 cases (13.0%), acute appendicitis with abscess in 6 cases (8.7%), acute appendicitis with appendicolith in 4 cases (5.8%) and perforated appendicitis in 4 cases (16%). 3. The ultrasonographic findings of normal appendix were in 69 cases (50%), those were nonvisualization of appendix in 62 cases (91.3%) and visualization of normal appendix with single thin echogenic wall in 6 cases (8.7%). 4. In the 50 cases of control group, the visualization of normal appendix on ultrasonography were in 8 cases (16%). 5. The overall accuwere in 8 cases (16%). 5. The overall accuracy was 95.7% with 97.1% of sensitivity and 94.4% of specificity

390

Pupillographic findings in neglect  

Digital Repository Infrastructure Vision for European Research (DRIVER)

OBJECTIVES—Unilateral sensory neglect has been attributed to various defects, including a hemispatial attention-arousal deficit. However, support for this hypothesis has only been indirect. Therefore, the purpose of this study was to further test the hemispatial attentional-arousal hypothesis by measuring pupillary response as an index of arousal.?METHODS—There were two experimental subjects with neglect and six matched controls. Stimuli (Arabic numbers) were presen...

Kim, M.; Schwartz, R.; Heilman, K.

1999-01-01

391

Calcaneal tendon: imaging findings  

International Nuclear Information System (INIS)

We reviewed the radiological and clinical features of 23 patients with calcaneal tendon diseases, who were submitted to ultrasound or magnetic resonance imaging. The objective of this study was to characterize the lesions for a precise diagnosis of calcaneal tendon injuries. A wide range of calcaneal tendon diseases include degenerative lesions, inflammation of the peritendinous tissue such as peritendinitis and bursitis, and rupture. Imaging methods are essential in the diagnosis, treatment and follow-up of calcaneal tendon diseases. (author)

392

Finding polynomials of best approximation with weight  

Science.gov (United States)

A new iterative method for finding the parameters of polynomials of best approximation with weight in C[-1, 1] is presented. It is based on the representation of the error in the trigonometric form in terms of the phase function. The iterative method of finding the corrections to the phase functions that determine the joint motion of the zeros and the e-points of the error is based on inverse analysis, perturbation theory, and asymptotic formulae for extremal polynomials. Bibliography: 24 titles.

Lebedev, V. I.

2008-02-01

393

Radiographic findings in immunodeficiency  

International Nuclear Information System (INIS)

This paper reviews the chest radiographs and high-resolution CT (HRCT) scans in patients with immunodeficiency disorders and define the role of HRCT. Thirty-three cases were retrospectively graded according to the consensus of two radiologists. Patients with HIV seropositivity and asthma were excluded. HRCT was performed in 12 cases with standard techniques. Diagnoses included common variable hypogammaglobulinemia (n = 19), X-linked agammaglobulinemia (n = 4), chronic mucocutaneous candidiasis (n = 4), and selective immunoglobulin g deficiencies (n = 2). Chest radiographs showed bronchiectasis in 11 of 33 cases with a predominant lower lobe distribution (82%). Nodules were present in six cases and mucus plugs in four cases. HRCT showed bronchiectasis in nine of 12 cases; in five of these nine cases, bronchiectasis was not apparent on chest radiographs. Other HRCT findings included segmental air trapping (four of 12), mucus plugs (three of 12), hazy consolidation (four of 12), nodules (five of 12), and bronchiolectasis (two of 12). Therapy was altered in seven of 12 cases in which HRCT was performed. Most pertinent to clinical management were the presence of a thymoma (n = 1) and severe focal of diffuse bronchiectasis

394

CT findings of hydranencephaly  

International Nuclear Information System (INIS)

Hydranencephaly is a destructive a developmental disorder that results in partial or complete absence of cerebral hemispheres with resulting cavity, filled with CSF. But it does not involve the skull, meninges and cerebellum. CT prove to be unique tool in diagnosis of hydranencephaly. We analysed CT findings of 6 patients with hydranencephaly who visited