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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

1979-10-19

2

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

CERN Multimedia

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

3

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

4

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.

5

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 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

2009-03-01

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

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

8

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

9

Path integral centroid molecular dynamics method for Bose and Fermi statistics: formalism and simulation  

Science.gov (United States)

A method is proposed for path integral centroid molecular dynamics (CMD) extended to Bose/Fermi statistics. It is based on the `pseudo-Boltzmann' canonical partition function of quantum statistical mechanics. An extended technique of path integral molecular dynamics (PIMD) is further presented for the calculation of thermodynamic properties and centroid mean force of Bose/Fermi systems. Bosonic PIMD and CMD simulations have been performed for 4He and the ideal Bose gas, respectively. The remnant of ? transition is observed for 4He, while Bose statistics causes a decay of the centroid velocity autocorrelation function of the ideal Bose gas in a nanosecond scale.

Kinugawa, Kenichi; Nagao, Hidemi; Ohta, Koji

1999-07-01

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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

11

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.

2009-11-10

12

Initial evaluation of Centroidal Voronoi Tessellation method for statistical sampling and function integration.  

Energy Technology Data Exchange (ETDEWEB)

A recently developed Centroidal Voronoi Tessellation (CVT) unstructured sampling method is investigated here to assess its suitability for use in statistical sampling and function integration. CVT efficiently generates a highly uniform distribution of sample points over arbitrarily shaped M-Dimensional parameter spaces. It has recently been shown on several 2-D test problems to provide superior point distributions for generating locally conforming response surfaces. In this paper, its performance as a statistical sampling and function integration method is compared to that of Latin-Hypercube Sampling (LHS) and Simple Random Sampling (SRS) Monte Carlo methods, and Halton and Hammersley quasi-Monte-Carlo sequence methods. Specifically, sampling efficiencies are compared for function integration and for resolving various statistics of response in a 2-D test problem. It is found that on balance CVT performs best of all these sampling methods on our test problems.

Romero, Vicente Jose; Peterson, Janet S. (Florida State University, Tallahassee, FL); Burkhardt, John V. (Florida State University, Tallahassee, FL); Gunzburger, Max Donald (Florida State University, Tallahassee, FL)

2003-09-01

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

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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

2004-03-08

15

Repeatability and precision of a weighted centroid method for estimating dynamic in vivo tibiofemoral surface interactions in sheep.  

Science.gov (United States)

Persistent changes in joint biomechanics resulting from knee injury are thought to contribute to progressive cartilage damage and post-traumatic osteoarthritis (PTOA). The identification and quantification of in vivo tibiofemoral surface interactions are critical to understanding them, particularly abnormal interactions that are damaging to articular cartilage and other structures of the knee. In this study, we describe an approach for understanding such potential interactions by using a weighted centroid derived from in vivo stifle kinematics in sheep. Collectively, repeatability and sensitivity analyses indicate that the magnitude of the changes in tibiofemoral centroid location resulting from combined ligament transection is greater than the repeatability and precision of the current weighted centroid approach, making this method useful for describing the changes in dynamic surface interactions that may be relevant in the pathogenesis of PTOA in this stifle injury model. PMID:23742689

Beveridge, Jillian E; Shrive, Nigel G; Frank, Cyril B

2014-12-01

16

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 tr...

2013-01-01

17

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

18

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

19

A new method based on morphologic filter and ant colony algorithm to enhance centroid detection accuracy of Shack-Hartmann wavefront sensor  

Science.gov (United States)

Shack-Hartmann wavefront sensor (SHWFS) is widely used in adaptive optics systems. Its centroid detecting error is one of the main error sources in adaptive optical systems. There are many factors affecting the detecting accuracy such as photon shot noise, readout noise, background level of CCD camera and number of detecting pixels. It is very effective to enhance the centroid accuracy by setting the threshold for the images of the SHWFS. But in daytime, the sky background is strong and changes very fast. The threshold cannot be chosen automatically either. In this paper, a new method based on the morphologic filter and ant colony algorithm is proposed to improve the SHWFS centroid detecting accuracy. The principle of the morphologic filter and the ant colony algorithm is introduced and the simulation results are also presented. The results show the proposed method can enhance SHWFS centroid accuracy very well.

Zhang, Yanyan; Li, Mei; Rao, Changhui

2008-12-01

20

Weighted Centroid Modified Simplex and Linear Constrained Response Surface Optimization Methods for the Xbar-R Chart Variable Determination  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: Although economic Xbar-R chart designs do guarantee the minimal operating cost, they typically have poor levels of statistical performance measures. The obvious limitation of the economic design is that the Type I error rate seems to be very high for many situations and will cause a large number of false alarms. This situation leads to an investigation of appropriate levels of control chart variables which consist of a sample size, an interval between samples or sampling frequency and the control chart limits. Approach: Evolutionary operations via the weighed centroid modified simplex, WCMSM and linear constrained response surface optimization, LCRSOM, methods are applied to optimize the Xbar-R chart variables in the analytical model called as the operating cost function. WCMSM allows the simplex to converge more rapidly towards an optimum via the weighted centroid of the hyperface by expansion and multiple ways of simplex contraction along the line of conventional reflection in order to speed up the convergence. LCRSOM is a combination of the principles of experimental designs, least squares and related mathematical programming models to approach the optimum. Results: The computational results for economic Xbar-R charts via both methods reveal that the process quality level affects the total cost more than relevant errors from selecting and inspecting samples including identifying assignable causes. However, total costs obtained from the LCRSOM seem to be better for all process scenarios. Conclusions: On Xbar-R charts, if a process is at the high quality level the total cost is better than a process with a low quality level without a consideration of errors from selecting/inspecting samples and identifying assignable causes.

Pongchanun Luangpaiboon

2011-01-01

 
 
 
 
21

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

Energy Technology Data Exchange (ETDEWEB)

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.

Romero, Vicente J. [Model Validation and Uncertainty Quantification Department, Sandia National Laboratories, Albuquerque, NM 87185-0828 (United States)]. E-mail: vjromer@sandia.gov; Burkardt, John V. [School of Computational Science and Information Technology, Florida State University, Tallahassee, FL 32306-4120 (United States)]. E-mail: burkardt@csit.fsu.edu; Gunzburger, Max D. [School of Computational Science and Information Technology, Florida State University, Tallahassee, FL 32306-4120 (United States)]. E-mail: gunzburg@csit.fsu.edu; Peterson, Janet S. [School of Computational Science and Information Technology, Florida State University, Tallahassee, FL 32306-4120 (United States)]. E-mail: jspeters@csit.fsu.edu

2006-10-15

22

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

23

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

24

Adaptive centroid optimization for Shack-Hartmann wavefront sensor  

Science.gov (United States)

The accuracy of the Shack-Hartmann wavefront sensor (SHWS) for measuring the distortion wavefront is mainly dependent upon the measurement accuracy of the centroid of the focal spot. Many methods have been presented to improve the accuracy of the wavefront centroid measurement, but most of them are based on a point of improvement. Propose a complete centroid optimization method. Based on analyzing background noise of the focal spot image, the method of adaptive threshold denoising is introduced, then the sub-aperture detection windows are optimized by modified watershed algorithm, and the centroid of the focal spot is calculated by the higher moment centroid algorithm in an optimized window, where the linear interpolation have been used. Simulation and experimental results showed that the centroid detection window could automatically adjust its size, matching perfect with spot distribution area, and the proposed method could reach high precision and repeatability of focal spot centroid in some certain SNR.

Gan, Jinrui; Jing, Wenbo; Wang, Xiaoman

2013-12-01

25

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

26

Research on Centroid Position for Stairs Climbing Stability of Search and Rescue Robot  

Directory of Open Access Journals (Sweden)

Full Text Available This paper represents the relationship between the stability of stairs climbing and the centroid position of the search and rescue robot. The robot system is considered as a mass point-plane model and the kinematics features are analyzed to find the relationship between centroid position and the maximal pitch angle of stairs the robot could climb up. A computable function about this relationship is given in this paper. During the stairs climbing, there is a maximal stability-keeping angle depends on the centroid position and the pitch angle of stairs, and the numerical formula is developed about the relationship between the maximal stability-keeping angle and the centroid position and pitch angle of stairs. The experiment demonstrates the trustworthy and correction of the method in the paper.

Yan Guo

2011-01-01

27

The generalized centroid difference method for picosecond sensitive determination of lifetimes of nuclear excited states using large fast-timing arrays  

Energy Technology Data Exchange (ETDEWEB)

A novel method for direct electronic “fast-timing” lifetime measurements of nuclear excited states via ?–? coincidences using an array equipped with N?N equally shaped very fast high-resolution LaBr{sub 3}(Ce) scintillator detectors is presented. Analogous to the mirror symmetric centroid difference method, the generalized centroid difference method provides two independent “start” and “stop” time spectra obtained by a superposition of the N(N?1)?–? time difference spectra of the N detector fast-timing system. The two fast-timing array time spectra correspond to a forward and reverse gating of a specific ?–? cascade. Provided that the energy response and the electronic time pick-off of the detectors are almost equal, a mean prompt response difference between start and stop events is calibrated and used as a single correction for lifetime determination. These combined fast-timing arrays mean ?–? time-walk characteristics can be determined for 40keVmethod over the total dynamic range is mainly determined by the statistics. The setup of an N=4 detector fast-timing array delivered an absolute time resolving power of 3 ps for 10 000 ?–? events per total fast timing array start and stop time spectrum. The new method is tested over the total dynamic range by the measurements of known picosecond lifetimes in standard ?-ray sources.

Régis, J.-M., E-mail: regis@ikp.uni-koeln.de [Institut für Kernphysik der Universität zu Köln, Zülpicher Str. 77, 50937 Köln (Germany); Mach, H. [Departamento de Física Atómica y Nuclear, Universidad Complutense, 28040 Madrid (Spain); Simpson, G.S. [Laboratoire de Physique Subatomique et de Cosmologie Grenoble, 53, rue des Martyrs, 38026 Grenoble Cedex (France); Jolie, J.; Pascovici, G.; Saed-Samii, N.; Warr, N. [Institut für Kernphysik der Universität zu Köln, Zülpicher Str. 77, 50937 Köln (Germany); Bruce, A. [School of Computing, Engineering and Mathematics, University of Brighton, Lewes Road, Brighton BN2 4GJ (United Kingdom); Degenkolb, J. [Institut für Kernphysik der Universität zu Köln, Zülpicher Str. 77, 50937 Köln (Germany); Fraile, L.M. [Departamento de Física Atómica y Nuclear, Universidad Complutense, 28040 Madrid (Spain); Fransen, C. [Institut für Kernphysik der Universität zu Köln, Zülpicher Str. 77, 50937 Köln (Germany); Ghita, D.G. [Horia Hulubei National Institute for Physics and Nuclear Engineering, 77125 Bucharest (Romania); and others

2013-10-21

28

An efficient g-centroid location algorithm for cographs  

Directory of Open Access Journals (Sweden)

Full Text Available In 1998, Pandu Rangan et al. Proved that locating the g-centroid for an arbitrary graph is 𝒩𝒫-hard by reducing the problem of finding the maximum clique size of a graph to the g-centroid location problem. They have also given an efficient polynomial time algorithm for locating the g-centroid for maximal outerplanar graphs, Ptolemaic graphs, and split graphs. In this paper, we present an O(nm time algorithm for locating the g-centroid for cographs, where n is the number of vertices and m is the number of edges of the graph.

V. Prakash

2005-07-01

29

Weighted Centroid Correction Localization in Cellular Systems  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: There is a large demand for wireless Location-Based Service (LBS and it is provided by many wireless cellular systems. In process of positioning a Mobile Station (MS, the computing speed is as important as the positioning accuracy and the algorithm should also be resistant to environmental influences. Approach: A new positioning method based on Weighted Centroid Correction Localization (WCCL for wireless cellular systems is introduced in this article. Firstly, referring to the receiving-state of an MS in cellular systems, it computes a weighted centroid of surrounding Base Stations (BSs as a rough approximate position of the MS. Then, according to the distances between the MS and the BSs being less or bigger than the computed distances between the BSs and the weighted centroid, it corrects the coordinate of the weighted centroid towards the directions of the BSs by moving it closer or farther in turn. Results: According to our experiments, WCCL improves the positioning accuracy, as well as to provide a better resistance to environmental influences. Conclusion: As a modified centroid-based localization algorithm, WCCL obtains weighting factors from the receiving-state of MS in multi-cells structured cellular systems and obtains a better positioning result in cellular systems without updating the network equipment. Therefore, for the cellular positioning problem, WCCL algorithm can be an alternate solution.

Rong-Zheng Li

2011-01-01

30

A quantum generalization of intrinsic reaction coordinate using path integral centroid coordinates  

Energy Technology Data Exchange (ETDEWEB)

We propose a generalization of the intrinsic reaction coordinate (IRC) for quantum many-body systems described in terms of the mass-weighted ring polymer centroids in the imaginary-time path integral theory. This novel kind of reaction coordinate, which may be called the ''centroid IRC,'' corresponds to the minimum free energy path connecting reactant and product states with a least amount of reversible work applied to the center of masses of the quantum nuclei, i.e., the centroids. We provide a numerical procedure to obtain the centroid IRC based on first principles by combining ab initio path integral simulation with the string method. This approach is applied to NH{sub 3} molecule and N{sub 2}H{sub 5}{sup -} ion as well as their deuterated isotopomers to study the importance of nuclear quantum effects in the intramolecular and intermolecular proton transfer reactions. We find that, in the intramolecular proton transfer (inversion) of NH{sub 3}, the free energy barrier for the centroid variables decreases with an amount of about 20% compared to the classical one at the room temperature. In the intermolecular proton transfer of N{sub 2}H{sub 5}{sup -}, the centroid IRC is largely deviated from the ''classical'' IRC, and the free energy barrier is reduced by the quantum effects even more drastically.

Shiga, Motoyuki [Center for Computational Science and E-systems, Japan Atomic Energy Agency, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8587 (Japan); Fujisaki, Hiroshi [Department of Physics, Nippon Medical School, 2-297-2, Kosugi-cho, Nakahara, Kawasaki 211-0063 (Japan); Molecular Scale Team, Integrated Simulation of Living Matter Group, Computational Science Research Program, RIKEN, 2-1 Hirosawa, Wako 351-0198 (Japan)

2012-05-14

31

Diagnosis of multiple cancer types by shrunken centroids of gene expression.  

Science.gov (United States)

We have devised an approach to cancer class prediction from gene expression profiling, based on an enhancement of the simple nearest prototype (centroid) classifier. We shrink the prototypes and hence obtain a classifier that is often more accurate than competing methods. Our method of "nearest shrunken centroids" identifies subsets of genes that best characterize each class. The technique is general and can be used in many other classification problems. To demonstrate its effectiveness, we show that the method was highly efficient in finding genes for classifying small round blue cell tumors and leukemias. PMID:12011421

Tibshirani, Robert; Hastie, Trevor; Narasimhan, Balasubramanian; Chu, Gilbert

2002-05-14

32

Modified S2 and Pattern Search Methods to Find Optimal Cluster Centroid for Multi-Variable Functions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Identification of useful clusters in large datasets has attracted considerable interest in clustering process. Since data in the World Wide Web is increasing exponentially that affects on clustering accuracy and decision making, change in the concept between every cluster occurs named concept drift. To detect the difference of cluster distributions between the current data subset and previous clustering result, an algorithm called Drifting Concept Detection (DCD) and proper data labeling need...

2012-01-01

33

Micro-pixel accuracy centroid displacement estimation and detector calibration  

CERN Multimedia

Precise centroid estimation plays a critical role in accurate astrometry using telescope images. Conventional centroid estimation fits a template point spread function (PSF) to the image data. Because the PSF is typically not known to high accuracy due to wavefront aberrations and uncertainties in optical system, a simple Gaussian function is commonly used. PSF knowledge error leads to systematic errors in the conventional centroid estimation. In this paper, we present an accurate centroid estimation algorithm by reconstructing the PSF from well sampled (above Nyquist frequency) pixelated images. In the limit of an ideal focal plane array whose pixels have identical response function (no inter-pixel variation), this method can estimate centroid displacement between two 32$\\times$32 images to sub-micropixel accuracy. Inter-pixel response variations exist in real detectors, {\\it e.g.}~CCDs, which we can calibrate by measuring the pixel response of each pixel in Fourier space. The Fourier transforms of the inter...

Zhai, Chengxing; Goullioud, Renaud; Nemati, Bijan

2011-01-01

34

Deterministic methods to find primes  

CERN Document Server

Given a large positive integer $N$, how quickly can one construct a prime number larger than $N$ (or between $N$ and $2N$)? Using probabilistic methods, one can obtain a prime number in time at most $\\log^{O(1)} N$ with high probability by selecting numbers between $N$ and $2N$ at random and testing each one in turn for primality until a prime is discovered. However, if one seeks a deterministic method, then the problem is much more difficult, unless one assumes some unproven conjectures in number theory; brute force methods give a $O(N^{1+o(1)})$ algorithm, and the best unconditional algorithm, due to Odlyzko, has a run time of $O(N^{1/2 + o(1)})$. In this paper we discuss an approach that may improve upon the $O(N^{1/2+o(1)})$ bound, by suggesting a strategy to determine in time $O(N^{1/2-c})$ for some $c>0$ whether a given interval in $[N,2N]$ contains a prime. While this strategy has not been fully implemented, it can be used to establish partial results, such as being able to determine the \\emph{parity} ...

Polymath, D H J

2010-01-01

35

A variational centroid density procedure for the calculation of transmission coefficients for asymmetric barriers at low temperature  

International Nuclear Information System (INIS)

The low temperature behavior of the centroid density method of Voth, Chandler, and Miller (VCM) [J. Chem. Phys. 91, 7749 (1989)] is investigated for tunneling through a one-dimensional barrier. We find that the bottleneck for a quantum activated process as defined by VCM does not correspond to the classical bottleneck for the case of an asymmetric barrier. If the centroid density is constrained to be at the classical bottleneck for an asymmetric barrier, the centroid density method can give transmission coefficients that are too large by as much as five orders of magnitude. We follow a variational procedure, as suggested by VCM, whereby the best transmission coefficient is found by varying the position of the centroid until the minimum value for this transmission coefficient is obtained. This is a procedure that is readily generalizable to multidimensional systems. We present calculations on several test systems which show that this variational procedure greatly enhances the accuracy of the centroid density method compared to when the centroid is constrained to be at the barrier top. Furthermore, the relation of this procedure to the low temperature periodic orbit or ''instanton'' approach is discussed. copyright 1995 American Institute of Physics

1995-09-01

36

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

37

Halftoning with Weighted Centroidal Voronoi Tessellations  

Science.gov (United States)

We propose a method for halftoning grayscale images by drawing weighted centroidal Voronoi tessellations (WCVTs) with black lines on white image planes. Based on the fact that CVT approaches a uniform hexagonal lattice asymptotically, we derive a relationship of darkness between input grayscale images and the corresponding halftone images. Then the derived relationship is used for adjusting the contrast of the halftone images. Experimental results show that the generated halftone images can reproduce the original tone in the input images faithfully.

Inoue, Kohei; Urahama, Kiichi

38

Estimating the Doppler centroid of SAR data  

Digital Repository Infrastructure Vision for European Research (DRIVER)

After reviewing frequency-domain techniques for estimating the Doppler centroid of synthetic-aperture radar (SAR) data, the author describes a time-domain method and highlights its advantages. In particular, a nonlinear time-domain algorithm called the sign-Doppler estimator (SDE) is shown to have attractive properties. An evaluation based on an existing SEASAT processor is reported. The time-domain algorithms are shown to be extremely efficient with respect to requirements on calculations an...

2009-01-01

39

Weighted Centroid Correction Localization in Cellular Systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Problem statement: There is a large demand for wireless Location-Based Service (LBS) and it is provided by many wireless cellular systems. In process of positioning a Mobile Station (MS), the computing speed is as important as the positioning accuracy and the algorithm should also be resistant to environmental influences. Approach: A new positioning method based on Weighted Centroid Correction Localization (WCCL) for wireless cellular systems is introduced in...

Rong-Zheng Li; Xin-Long Luo; Jia-Ru Lin

2011-01-01

40

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

 
 
 
 
41

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.)

1981-09-15

42

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

43

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

44

GPU-Assisted Computation of Centroidal Voronoi Tessellation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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-...

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

2011-01-01

45

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

46

On Centroidal Voronoi Tessellation-Energy Smoothness and Fast Computation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Centroidal Voronoi tessellation (CVT) is a particular type of Voronoi tessellation that has many applications in computational sciences and engineering, including computer graphics. The prevail- ing method for computing CVT is Lloyd's method, which has linear convergence and is inefficient in practice. We develop new efficient methods for CVT computation and demonstrate the fast convergence of these methods. Specifically, we show that the CVT energy function has 2nd order smoothness for conve...

Liu, Yang; Wang, Wenping; Le?vy, Bruno; Sun, Feng; Yan, Dong-ming; Lu, Lin; Yang, Chenglei

2009-01-01

47

Estimating the Doppler centroid of SAR data  

DEFF Research Database (Denmark)

After reviewing frequency-domain techniques for estimating the Doppler centroid of synthetic-aperture radar (SAR) data, the author describes a time-domain method and highlights its advantages. In particular, a nonlinear time-domain algorithm called the sign-Doppler estimator (SDE) is shown to have attractive properties. An evaluation based on an existing SEASAT processor is reported. The time-domain algorithms are shown to be extremely efficient with respect to requirements on calculations and memory, and hence they are well suited to real-time systems where the Doppler estimation is based on raw SAR data. For offline processors where the Doppler estimation is performed on processed data, which removes the problem of partial coverage of bright targets, the Î?E estimator and the CDE (correlation Doppler estimator) algorithm give similar performance. However, for nonhomogeneous scenes it is found that the nonlinear SDE algorithm, which estimates the Doppler-shift on the basis of data signs alone, gives superior performance

Madsen, Søren Nørvang

1989-01-01

48

An Automatic Method of Finding Topic Boundaries  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article outlines a new method of locating discourse boundaries based on lexical cohesion and a graphical technique called dotplotting. The application of dotplotting to discourse segmentation can be performed either manually, by examining a graph, or automatically, using an optimization algorithm. The results of two experiments involving automatically locating boundaries between a series of concatenated documents are presented. Areas of application and future directions...

Reynar, Jeffrey C.

1994-01-01

49

Diagnosis of multiple cancer types by shrunken centroids of gene expression  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have devised an approach to cancer class prediction from gene expression profiling, based on an enhancement of the simple nearest prototype (centroid) classifier. We shrink the prototypes and hence obtain a classifier that is often more accurate than competing methods. Our method of “nearest shrunken centroids” identifies subsets of genes that best characterize each class. The technique is general and can be used in many other classification problems. To demonstrate its effectiveness, ...

Tibshirani, Robert; Hastie, Trevor; Narasimhan, Balasubramanian; Chu, Gilbert

2002-01-01

50

2D Centroidal Voronoi Tessellations with Constraints  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We tackle the problem of constructing 2D centroidal Voronoi tessellations with constraints through an efficient and robust construction of bounded Voronoi diagrams, the pseudo-dual of the constrained Delaunay triangulation. We exploit the fact that the cells of the bounded Voronoi diagram can be obtained by clipping the ordinary ones against the constrained Delaunay edges. The clipping itself is efficiently computed by identifying for each constrained edge the (connected) set of triangles who...

Tournois, Jane; Alliez, Pierre; Devillers, Olivier

2010-01-01

51

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

CERN Multimedia

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

52

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

53

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 population. (orig.)

2007-08-01

54

Computing 2D Periodic Centroidal Voronoi Tessellation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, we propose an efficient algorithm to compute the centroidal Voronoi tessellation in 2D periodic space. We first present a simple algorithm for constructing the periodic Voronoi diagram (PVD) from a Euclidean Voronoi diagram. The presented PVD algorithm considers only a small set of periodic copies of the input sites, which is more efficient than previous approaches requiring full copies of the sites (9 in 2D and 27 in 3D). The presented PVD algorithm is applied in a fast Newton...

Yan, Dong-ming; Wang, Kai; Le?vy, Bruno; Alonso, Laurent

2011-01-01

55

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

56

Method of Finding Hamilton Routes in Transport Network  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article discusses a solution method for Hamilton Problem, which either finds the task's solution, or indicates that the task is unsolvable. Offered method has significantly smaller requirements for computing resources than known algorithms.

Garashchenko, Irina; Panishev, Anatoliy

2008-01-01

57

Computing the apparent centroid of radar targets  

Energy Technology Data Exchange (ETDEWEB)

A high-frequency multibounce radar scattering code was used as a simulation platform for demonstrating an algorithm to compute the ARC of specific radar targets. To illustrate this simulation process, several targets models were used. Simulation results for a sphere model were used to determine the errors of approximation associated with the simulation; verifying the process. The severity of glint induced tracking errors was also illustrated using a model of an F-15 aircraft. It was shown, in a deterministic manner, that the ARC of a target can fall well outside its physical extent. Finally, the apparent radar centroid simulation based on a ray casting procedure is well suited for use on most massively parallel computing platforms and could lead to the development of a near real-time radar tracking simulation for applications such as endgame fuzing, survivability, and vulnerability analyses using specific radar targets and fuze algorithms.

Lee, C.E.

1996-12-31

58

Accurate Alignment of Plasma Channels Based on Laser Centroid Oscillations  

Energy Technology Data Exchange (ETDEWEB)

A technique has been developed to accurately align a laser beam through a plasma channel by minimizing the shift in laser centroid and angle at the channel outptut. If only the shift in centroid or angle is measured, then accurate alignment is provided by minimizing laser centroid motion at the channel exit as the channel properties are scanned. The improvement in alignment accuracy provided by this technique is important 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

2011-03-23

59

Accurate Alignment of Plasma Channels Based on Laser Centroid Oscillations  

International Nuclear Information System (INIS)

A technique has been developed to accurately align a laser beam through a plasma channel by minimizing the shift in laser centroid and angle at the channel outptut. If only the shift in centroid or angle is measured, then accurate alignment is provided by minimizing laser centroid motion at the channel exit as the channel properties are scanned. The improvement in alignment accuracy provided by this technique is important for minimizing electron beam pointing errors in laser plasma accelerators.

2011-04-01

60

Alternative method to find orbits in chaotic systems  

CERN Document Server

We present here a new method which applies well ordered symbolic dynamics to find unstable periodic and non-periodic orbits in a chaotic system. The method is simple and efficient and has been successfully applied to a number of different systems such as the H\\'enon map, disk billiards, stadium billiard, wedge billiard, diamagnetic Kepler problem, colinear Helium atom and systems with attracting potentials. The method seems to be better than earlier applied methods.

Hansen, K T

1995-01-01

 
 
 
 
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)

2007-01-01

62

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

63

Modified string method for finding minimum energy path  

CERN Document Server

We present an efficient algorithm to calculate minimum energy path (MEP) and energy barriers between locally minimum points on the multidimensional potential energy surface (PES). Our method dwells the original idea of the String method [Phys. Rev. B 66, 052301 (2002)] to evolve a smooth string along a direction normal to the string. The algorithm works by identifying hyperplanes, at each discretized point, normal to path. The intermediate configurations at these discretized points are then relaxed with their motion confined to their corresponding hyperplanes. Thus the problem of finding MEP on the PES is remodeled as a set of constrained minimization problem. This provides the flexibility of using minimization algorithms faster than the steepest descent method used in the simplified string method [J. Chem. Phys.,126(16),164103 (2007)]. In our method, since each intermediate image relaxes independently, if their step lengths are not controlled kinks can form easily. We propose using a mixing scheme to advance...

Samanta, Amit

2010-01-01

64

Optimization of Existing Centroiding Algorithms for Shack Hartmann Sensor  

CERN Document Server

Three centroiding techniques to estimate the position of the spots in a Shack Hartmann sensor: Normalized Centre of Gravity (CoG), Iteratively Weighted Centre of Gravity (IWCoG) and Intensity Weighted (IWC) centroiding are studied in comparison. The spot pattern at the focal plane of a Shack Hartmann sensor was simulated by including the effect of a background noise. We present the results of optimization of the performance of each of the centroiding techniques as a function of Signal to Noise Ratio (SNR) at different experimental conditions.

Vyas, Akondi; Prasad, B R

2009-01-01

65

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

66

Time-domain calculation of spectral centroid from backscattered ultrasound signals.  

Science.gov (United States)

Spectral centroid estimation from backscattered ultrasound RF signals is the preliminary step for quantitative ultrasound analysis in many medical applications. The traditional approach of estimating the spectral centroid in the frequency domain takes a long time because discrete Fourier transform (DFT) processing for each RF segment is required. To avoid this, we propose time-domain methods to estimate the spectral centroid in this paper. First, we derive the continuous-time-domain equations for the spectral centroid estimation using Parseval's theorem and Hilbert transform theory. Then, we extend the method to the discrete-time domain to ease the implementation while maintaining the same accuracy as the calculation in the frequency domain. From the result, we observe that it is not practical to apply the discrete-time equations directly, because a high sampling rate is needed to approximate the time derivative in the discrete-time domain. Therefore, we also derive the feasible version of the discrete-time equations using a circular autocorrelation function, which has no constraints on the sampling rate for real RF signals acquired from pulse-echo ultrasound systems. Simulation results using numerical phantoms show that the time-domain calculation is approximately 4.4 times faster on average than the frequency-domain method when the software's built-in functions were used. The average estimation error compared with that of the frequency-domain method using DFT is less than 0.2% for the entire propagation depths. The proposed time-domain approach to estimate the spectral centroid can be easily implemented in real-time ultrasound systems. PMID:22711414

Kim, Hyungsuk; Heo, Seo Weon

2012-06-01

67

Ambiguity Of Doppler Centroid In Synthetic-Aperture Radar  

Science.gov (United States)

Paper discusses performances of two algorithms for resolution of ambiguity in estimated Doppler centroid frequency of echoes in synthetic-aperture radar. One based on range-cross-correlation technique, other based on multiple-pulse-repetition-frequency technique.

Chang, Chi-Yung; Curlander, John C.

1991-01-01

68

An Investigation of Spectral Subband Centroids for Speaker Authentication  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Most conventional features used in speaker authentication are based on estimation of spectral envelopes in one way or another, in the form of cepstrums, e.g., Mel-scale Filterbank Cepstrum Coefficients (MFCCs), Linear-scale Filterbank Cepstrum Coefficients (LFCCs) and Relative Spectral Perceptual Linear Prediction (RASTA-PLP). In this study, Spectral Subband Centroids (SSCs) are examined. These features are the centroid frequency in each subband. They have properties similar to the formant fr...

Poh, Norman; Sanderson, Conrad; Bengio, Samy

2003-01-01

69

An Investigation of Spectral Subband Centroids for Speaker Authentication  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Most conventional features used in speaker authentication are based on estimation of spectral envelopes in one way or another, in the form of cepstrums, e.g., Mel-scale Filterbank Cepstrum Coefficients (MFCCs), Linear-scale Filterbank Cepstrum Coefficients (LFCCs) and Relative Spectral Perceptual Linear Prediction (RASTA-PLP). In this study, Spectral Subband Centroids (SSCs) are examined. These features are the centroid frequency in each subband. They have properties similar to the formant fr...

Poh, Norman; Sanderson, Conrad; Bengio, Samy

2004-01-01

70

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

71

A study on the uncertainties of the centroid depth of the 2013 Lushan earthquake from teleseimic body wave data  

Science.gov (United States)

Centroid depth of earthquakes is essential for seismic hazard mitigation. But, various studies provided different solutions for the centroid depth of the damaging 2013 Lushan earthquake, thus hindering further studies of the earthquake processes. To resolve its centroid depth and assess the uncertainties, we apply the teleseismic cut and paste method to invert for centroid depth with teleseismic body waves in the epicentral distance of 30°-90°. We performed the inversion for P waves only as well the case of both P and SH waves and found that both cases lead to depth solutions with difference less than 0.5 km. We also investigated the effects on depth inversion from azimuth gap of seismic stations, source duration, and corner frequency of filter. These various tests show that even azimuthal distribution of seismic stations is helpful for accurate depth inversion. It is also found that estimate of centroid depth is sensitive to source duration. Moreover, the depth is biased to larger values when corner frequency of low-pass filter is very low. The uncertainty in the velocity model can also generate some error in the depth estimation (~1.0 km).With all the above factors considered, the centroid depth of Lushan earthquake is proposed to be around 12 km, with uncertainty about 2 km.

Chen, Weiwen; Wang, Decai; Wei, Shengji

2013-08-01

72

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

73

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

74

Automatic extraction of nuclei centroids of mouse embryonic cells from fluorescence microscopy images.  

Science.gov (United States)

Accurate identification of cell nuclei and their tracking using three dimensional (3D) microscopic images is a demanding task in many biological studies. Manual identification of nuclei centroids from images is an error-prone task, sometimes impossible to accomplish due to low contrast and the presence of noise. Nonetheless, only a few methods are available for 3D bioimaging applications, which sharply contrast with 2D analysis, where many methods already exist. In addition, most methods essentially adopt segmentation for which a reliable solution is still unknown, especially for 3D bio-images having juxtaposed cells. In this work, we propose a new method that can directly extract nuclei centroids from fluorescence microscopy images. This method involves three steps: (i) Pre-processing, (ii) Local enhancement, and (iii) Centroid extraction. The first step includes two variations: first variation (Variant-1) uses the whole 3D pre-processed image, whereas the second one (Variant-2) modifies the preprocessed image to the candidate regions or the candidate hybrid image for further processing. At the second step, a multiscale cube filtering is employed in order to locally enhance the pre-processed image. Centroid extraction in the third step consists of three stages. In Stage-1, we compute a local characteristic ratio at every voxel and extract local maxima regions as candidate centroids using a ratio threshold. Stage-2 processing removes spurious centroids from Stage-1 results by analyzing shapes of intensity profiles from the enhanced image. An iterative procedure based on the nearest neighborhood principle is then proposed to combine if there are fragmented nuclei. Both qualitative and quantitative analyses on a set of 100 images of 3D mouse embryo are performed. Investigations reveal a promising achievement of the technique presented in terms of average sensitivity and precision (i.e., 88.04% and 91.30% for Variant-1; 86.19% and 95.00% for Variant-2), when compared with an existing method (86.06% and 90.11%), originally developed for analyzing C. elegans images. PMID:22590505

Bashar, Md Khayrul; Komatsu, Koji; Fujimori, Toshihiko; Kobayashi, Tetsuya J

2012-01-01

75

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

76

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

77

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 Union

1998-11-01

78

Robust of Doppler Centroid for Mapping Sea Surface Current by Using Radar Satellite Data  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: Sea surface current retrieving from Synthetic Aperture Radar (SAR is required standard methods due to the complexity of sea surface ocean imaging in SAR data. In this context, various analytical models have been developed which describe overall effects of sea surface roughness on the Doppler signal mechanisms. Nevertheless, such models are limited in the complexity of the sea surface current estimation that can be used. In fact, the resolution of the sea surface Doppler velocity in azimuth direction is typically coarser as compared to the normalized radar cross section image. Approach: This study introduced a new method to retrieve sea surface current from RADARSAT-1 SAR Standard beam mode (S2 data. The method was based on the utilization of the Wavelength Diversity Ambiguity Resolving (WDAR and Multi Look beat Frequency (MLBF algorithms to remove Doppler centroid (fDC ambiguity. Results: The result showed that the proposed methods are able to correct Doppler centroid (fDC ambiguity and produced fine spatial sea surface current variations in S2 mode data. The current velocities were ranged between 0.18 and 0.78 m sec-1 with standard error of 0.11 m sec-1. Conclusion: In conclusion, RADARSAT-1 SAR standard beam mode (S2 data can be utilized to retrieve real time sea surface current. Both WDAR and MLBF algorithms are able to provide accurately information on Doppler Centroid (fDC in which accurately real time sea surface current can be retrieved from SAR data.

Mazlan Hashim

2009-01-01

79

Fixed J spectral distribution in large shell model spaces. II. Fixed J configuration centroids and widths  

International Nuclear Information System (INIS)

A method is developed to exactly calculate the fixed J configuration centroid energies and widths. The resulting approximate level densities for "2"0"4Pb and "2"0"2Pb show large departures with respect to the gaussian approximate level densities. The goodness of the polynomial expansion of fixed J configuration moments is studied and a simple improvement to this approximation is proposed which gives very good results

1981-01-01

80

Using centroid based nearest neighbor classifier in predicting small molecule activity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Small molecules, especially those which alter biological processes and disease states, are of significant interest. Predicting the specific bioactivities of small molecules is a general problem that has attracted particular attention. Nearest Neighbor(NN) classification is one of the most widely used methods for small molecule classification, but it suffers from both speed and overfitting. We propose a variation, namely Centroid based Nearest Neighbor (CBNN) classifier to solve NN problems, a...

Hormozdiari, Farhad

2009-01-01

 
 
 
 
81

A Statistical Study of Beam Centroid Oscillations in a Solenoid Transport Channel  

Energy Technology Data Exchange (ETDEWEB)

A recent theory of transverse centroid oscillations in solenoidally focused beam transport lattices presented in Ref. [1] is applied to statistically analyze properties of the centroid orbit in the Neutralized Drift Compression Experiment (NDCX) at the Lawrence Berkeley National Laboratory. Contributions to the amplitude of the centroid oscillations from mechanical misalignments and initial centroid errors exiting the injector are analyzed. Measured values of the centroid appear consistent with expected alignment tolerances. Correction of these errors is discussed.

Lund, S; Wootton, C; Coleman, J; Lidia, S; Seidl, P

2009-05-07

82

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

83

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

84

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

85

Relation between medium fluid temperature and centroid subchannel temperatures of a nuclear fuel bundle mock-up  

International Nuclear Information System (INIS)

The subchannel method used in nuclear fuel bundle thermal-hydraulic analysis lies in the statement that subchannel fluid temperatures are taken at mixed mean values. However, the development of mixing correlations and code assessment procedures are, sometimes in the literature, based upon the assumption of identity between lumped and local (subchannel centroid) temperature values. The present paper is concerned with the presentation of an approach for correlating lumped to centroid subchannel temperatures, based upon previously formulated models by the author, applied to a nine heated tube bundle experimental data set. (Author)

1986-03-17

86

An integrating factor matrix method to find first integrals  

Energy Technology Data Exchange (ETDEWEB)

In this paper we develop an integrating factor matrix method to derive conditions for the existence of first integrals. We use this novel method to obtain first integrals, along with the conditions for their existence, for two- and three-dimensional Lotka-Volterra systems with constant terms. The results are compared to previous results obtained by other methods.

Saputra, K V I [Faculty of Science and Mathematics, University Pelita Harapan, Jl. MH Thamrin Boulevard, Tangerang Banten, 15811 (Indonesia); Quispel, G R W [Department of Mathematics and Statistical Science, La Trobe University, Bundoora 3086 (Australia); Van Veen, L, E-mail: kie.saputra@staff.uph.ed [Faculty of Science, University of Ontario Institute of Technology, 2000 Simcoe St N., Oshawa, Ontario, L1H 7K4 (Canada)

2010-06-04

87

An integrating factor matrix method to find first integrals  

CERN Document Server

In this paper we developed an integrating factor matrix method to derive conditions for the existence of first integrals. We use this novel method to obtain first integrals, along with the conditions for their existence, for two and three dimensional Lotka-Volterra systems with constant terms. The results are compared to previous results obtained by other methods.

Saputra, K V I; van Veen, L

2010-01-01

88

A homotopy method for finding eigenvalues and eigenvectors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Suppose we want to find the eigenvalues and eigenvectors for the linear operator L, and suppose that we have solved this problem for some other "nearby" operator K. In this paper we show how to represent the eigenvalues and eigenvectors of L in terms of the corresponding properties of K.

Soileau, Kerry M.

2007-01-01

89

Centroid Detection by Gaussian Pattern Matching in Adaptive Optics  

CERN Document Server

Shack Hartmann wavefront sensor is a two dimensional array of lenslets which is used to detect the incoming phase distorted wavefront through local tilt measurements made by recording the spot pattern near the focal plane. Wavefront reconstruction is performed in two stages - (a) image centroiding to calculate local slopes, (b) formation of the wavefront shape from local slope measurement. Centroiding accuracy contributes to most of the wavefront reconstruction error in Shack Hartmann sensor based adaptive optics system with readout and background noise. It becomes even more difficult in atmospheric adaptive optics case, where scintillation effects may also occur. In this paper we used a denoising technique based on thresholded Zernike reconstructor to minimize the effects due to readout and background noise. At low signal to noise ratio, this denoising technique can be improved further by taking the advantage of the shape of the spot. Assuming a Gaussian pattern for individual spots, it is shown that the cen...

Vyas, Akondi; Prasad, B Raghavendra

2009-01-01

90

Markovian Method of Finding the Availability of Repairable Systems  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper the transition probability matrix is used to tackle the problem of the availability of repairable systems. The method is applicable to a system governed by a two-parameter distribution for the life-time and repair-time. It will be concentrated on the Weibull and Gamma distributions without and/or with singularities. The method is involving matrices multiplication of massive size. For this purpose an arithmetic method is applied to carry out this multiplication that, in turn, represents the availability of a repairable system.

M. Y. Ashkar

2011-05-01

91

Uncertain Centroid based Partitional Clustering of Uncertain Data  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Clustering uncertain data has emerged as a challenging task in uncertain data management and mining. Thanks to a computational complexity advantage over other clustering paradigms, partitional clustering has been particularly studied and a number of algorithms have been developed. While existing proposals differ mainly in the notions of cluster centroid and clustering objective function, little attention has been given to an analysis of their characteristics and limits. In t...

Gullo, Francesco; Tagarelli, Andrea

2012-01-01

92

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 obtain...

Mohammad Zohrabi

2013-01-01

93

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Jang, Seogjoo

2013-01-01

94

General Method for Finding the Most Economical Distributed Router Architecture  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this work we present a novel method to determine the optimal parameters of a router architecture when certain router performance constraints are given. The total financial expense, or cost, is the optimality criterion. We introduce a general, essentially distributed, router architecture model, consisting of locally or remotely located forwarding engines or processing units gathered around a switch of variable speed. Given the following constraints: number of inputs, maximum line interface ...

2002-01-01

95

A Simple Method To Find All Lensed Quasars  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We demonstrate that gravitationally lensed quasars are easily recognized using image subtraction methods as time variable sources that are spatially extended. For Galactic latitudes |b|>20 deg, lensed quasars dominate the population of spatially extended variable sources, although there is some contamination from variable star pairs, variable star-quasar pairs and binary quasars that can be easily controlled using other information in the survey such as the object light curv...

Kochanek, C. S.; Mochejska, B.; Morgan, N. D.; Stanek, K. Z.

2005-01-01

96

Finding Methods for Innovative Packaging Development: The Card Approach  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Innovation strategies are crucial for corporate success and should be a top priority for packaging companies. However, to improve the innovativeness of packaging manufacturers, there is a need to increase the integration of product and packaging development and collaboration within the supply chain. New methods for innovative packaging development are needed. Packaging plays a valuable role in the marketing and distribution of products, and can thus add great value for actors in the su...

Magnusson, Amanda; Olander, Malin; Olsson, Annika

2013-01-01

97

Signature of B-CLL with different prognosis by Shrunken centroids of surface antigen expression profiling.  

Science.gov (United States)

With the aim of identifying the immunophenotypic profile of B-cell chronic lymphocytic leukemia (B-CLL) subsets with different prognosis, we investigated by flow cytometry the expression of 36 surface antigens in 123 cases, all with survivals. By analyzing results with unsupervised (hierarchical and K-means clustering) algorithms, three distinct immunophenotypic groups (I, II, and III) were identified, group I (51/123) with longer survivals, as compared to the group II (36/123) and III (36/123). The immunophenotypic signatures of these groups, as determined by applying the nearest Shrunken centroids method as class predictor, were characterized by the coordinated and differential expression of 12 surface markers, that is, group I: above-average expression of CD62L, CD54, CD49c, and CD25, below-average expression of CD38; group II: above-average expression of CD38, CD49d, CD29, and CD49e; and group III: below-average expression of the above markers, overexpression of CD23, CD20, SmIg, and CD79b. As opposed to groups II-III, group I B-CLLs lacked expression of ZAP-70 and activation-induced cytidine deaminase in the majority of cases, while more frequently had mutated IgV(H) genes and IgV(H) mutations consistent with antigen-driven selection. Our findings contribute to improve the immunophenotypical identification of disease subsets with different prognosis and suggest a set of surface antigens to be employed as prognosticators in routine diagnostic/prognostic procedures. PMID:15605425

Zucchetto, Antonella; Sonego, Paolo; Degan, Massimo; Bomben, Riccardo; Dal Bo, Michele; Russo, Stefania; Attadia, Vincenza; Rupolo, Maurizio; Buccisano, Francesco; Del Principe, Maria Ilaria; Del Poeta, Giovanni; Pucillo, Carlo; Colombatti, Alfonso; Campanini, Renato; Gattei, Valter

2005-07-01

98

Variational method for finding periodic orbits in a general flow.  

Science.gov (United States)

A variational principle is proposed and implemented for determining unstable periodic orbits of flows as well as unstable spatiotemporally periodic solutions of extended systems. An initial loop approximating a periodic solution is evolved in the space of loops toward a true periodic solution by a minimization of local errors along the loop. The "Newton descent" partial differential equation that governs this evolution is an infinitesimal step version of the damped Newton-Raphson iteration. The feasibility of the method is demonstrated by its application to the Hénon-Heiles system, the circular restricted three-body problem, and the Kuramoto-Sivashinsky system in a weakly turbulent regime. PMID:14995703

Lan, Yueheng; Cvitanovi?, Predrag

2004-01-01

99

Variational method for finding periodic orbits in a general flow  

CERN Multimedia

A variational principle for determining unstable periodic orbits of flows as well as unstable spatio-temporally periodic solutions of extended systems is proposed and implemented. An initial loop approximating a periodic solution is evolved in the space of loops toward a true periodic solution by a minimization of local errors along the loop. The ``\\descent'' partial differential equation that governs this evolution is an infinitesimal step version of the damped Newton-Raphson iteration. The feasibility of the method is demonstrated by its application to the H\\'enon-Heiles system, the circular restricted three-body problem, and the Kuramoto-Sivashinsky system in a weakly turbulent regime.

Lan, Y

2004-01-01

100

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.)

2009-12-01

 
 
 
 
101

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

102

A method for finding plasmasphere statistics from solar wind measurements  

International Nuclear Information System (INIS)

This paper gives the results of a calculation of the characteristic size of the plasmasphere based on a specific formulation of the prevailing view that its size is determined by a dynamic equilibrium between two essentially independent processes: depletion by magnetospheric convection and refill by flux from the ionosphere. The first of these processes exhibits a time behavior best described as being stochastic. The characteristic size of the plasmasphere is therefore also stochastic. The formulation given here combines simple models of dayside magnetic merging, corotation and convection patterns, and the refill process. It predicts statistical characteristics of the plasmasphere size from measurements of the solar wind convection electric field. From Mariner 5 measurements the method predicts the median value of the characteristic size of the plasmasphere to be 4.8 R/sub E/ with a 50% central range of 3.8--5.2 R/sub E/, values entirely compatible with observations. Although the method gives no information about the shape of the plasmapause, it has the advantage that it can be applied to geophysical situations different from those that exist at present. This is illustrated by applying it to a case in which the dipole strength is double the present value

1977-03-01

103

Findings from analysing and quantifying human error using current methods  

International Nuclear Information System (INIS)

In human reliability analysis (HRA), the scarcity of data means that, at best, judgement must be applied to transfer to the domain of the analysis what data are available for similar tasks. In particular for the quantification of tasks involving decisions, the analyst has to choose among quantification approaches that all depend to a significant degree on expert judgement. The use of expert judgement can be made more reliable by eliciting relative judgements rather than absolute judgements. These approaches, which are based on multiple criterion decision theory, focus on ranking the tasks to be analysed by difficulty. While these approaches remedy at least partially the poor performance of experts in the estimation of probabilities, they nevertheless require the calibration of the relative scale on which the actions are ranked in order to obtain the probabilities of interest. This paper presents some results from a comparison of some current HRA methods performed in the frame of a study of SLIM calibration options. The HRA quantification methods THERP, HEART, and INTENT were applied to derive calibration human error probabilities for two groups of operator actions. (author)

1999-01-01

104

Direct assessment of quantum nuclear effects on hydrogen bond strength by constrained-centroid ab initio path integral molecular dynamics  

Science.gov (United States)

The impact of quantum nuclear effects on hydrogen (H-) bond strength has been inferred in earlier work from bond lengths obtained from path integral molecular dynamics (PIMD) simulations. To obtain a direct quantitative assessment of such effects, we use constrained-centroid PIMD simulations to calculate the free energy changes upon breaking the H-bonds in dimers of HF and water. Comparing ab initio simulations performed using PIMD and classical nucleus molecular dynamics (MD), we find smaller dissociation free energies with the PIMD method. Specifically, at 50 K, the H-bond in (HF)2 is about 30% weaker when quantum nuclear effects are included, while that in (H2O)2 is about 15% weaker. In a complementary set of simulations, we compare unconstrained PIMD and classical nucleus MD simulations to assess the influence of quantum nuclei on the structures of these systems. We find increased heavy atom distances, indicating weakening of the H-bond consistent with that observed by direct calculation of the free energies of dissociation.

Walker, Brent; Michaelides, Angelos

2010-11-01

105

Ab initio centroid path integral molecular dynamics: Application to vibrational dynamics of diatomic molecular systems  

Science.gov (United States)

An ab initio centroid molecular dynamics (CMD) method is developed by combining the CMD method with the ab initio molecular orbital method. The ab initio CMD method is applied to vibrational dynamics of diatomic molecules, H2 and HF. For the H2 molecule, the temperature dependence of the peak frequency of the vibrational spectral density is investigated. The results are compared with those obtained by the ab initio classical molecular dynamics method and exact quantum mechanical treatment. It is shown that the vibrational frequency obtained from the ab initio CMD approaches the exact first excitation frequency as the temperature lowers. For the HF molecule, the position autocorrelation function is also analyzed in detail. The present CMD method is shown to well reproduce the exact quantum result for the information on the vibrational properties of the system.

Ohta, Yasuhito; Ohta, Koji; Kinugawa, Kenichi

2004-01-01

106

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

107

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

2002-01-01

108

On the applicability of centroid and ring polymer path integral molecular dynamics for vibrational spectroscopy  

Science.gov (United States)

Centroid molecular dynamics (CMD) and ring polymer molecular dynamics (RPMD) are two conceptually distinct extensions of path integral molecular dynamics that are able to generate approximate quantum dynamics of complex molecular systems. Both methods can be used to compute quasiclassical time correlation functions which have direct application in molecular spectroscopy; in particular, to infrared spectroscopy via dipole autocorrelation functions. The performance of both methods for computing vibrational spectra of several simple but representative molecular model systems is investigated systematically as a function of temperature and isotopic substitution. In this context both CMD and RPMD feature intrinsic problems which are quantified and investigated in detail. Based on the obtained results guidelines for using CMD and RPMD to compute infrared spectra of molecular systems are provided.

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

2009-05-01

109

Beam centroid and envelope model for the SLIA accelerator  

Science.gov (United States)

The RAM computer code has been developed to model the Spiral Line Induction Accelerator (SLIA), which is under development at Pulse Sciences Inc. (PSI). The code advances the beam centroid and envelope equations for a complete current pulse in this high-current recirculating accelerator. Since the beam cross-section is elliptical, in general, and the transverse x-y motions are coupled via an axial magnetic field, the beam envelope is modeled using a 4 × 4 covariance matrix. The envelope equation includes a correction for beam diamagnetism. Toroidal self-field contributions to the bending field and the transverse frequencies have been calculated; the results retain terms which were inconsistently omitted in previous derivations, leading to incorrect frequencies. The code uses a circuit model to compute the beam-loading effect on the accelerating voltage at each gap. The transverse gap forces, which drive the beam breakup (BBU) instability are also computed. Realistic field maps for all beamline elements (solenoids, stellarator coils, bending fields, and matching quadrupoles) are incorporated.

Hughes, Thomas P.; Genoni, Thomas C.

1996-05-01

110

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

Science.gov (United States)

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.

Tremsin, Anton S.; McPhate, Jason B.; Vallerga, John V.; Siegmund, Oswald H. W.; Bruce Feller, W.; Lehmann, Eberhard; Kaestner, Anders; Boillat, Pierre; Panzner, Tobias; Filges, Uwe

2012-10-01

111

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.

2012-10-01

112

Interpolating filter for centroid finding of induced charge in Multiwire Proportional Chambers (MWPCs) with strip cathodes  

Energy Technology Data Exchange (ETDEWEB)

An interpolating filter has been devised for reducing differential and integral nonlinearity in the measurements of the avalanche position in MWPCs by the charge induced on cathode strips. Theoretical computations and experimental results for the case of one amplifier per strip are presented showing a significant improvement of the linearity.

Gatti, E.; Longoni, A. (Politecnico di Milano (Italy). Ist. di Fisica); Radeka, V. (Brookhaven National Lab., Upton, NY (USA); Politecnico di Milano (Italy). Centro Elettronica Quantistica e Strumentazione Elettronica)

1984-03-01

113

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

114

A Method for Finding the Extreme of Certain Polynomials Using Inequalities of the Mean  

Directory of Open Access Journals (Sweden)

Full Text Available A polynomial y = p(x is continuous and differentiable on its domain R. Therefore, at any closed interval, the graph attains both the maximum and minimum values in the stationary points or the borders of the interval. The method commonly used to find the extremum is Calculus by using derivatives. This paper presents a method for finding the extremum of certain polynomials using inequalities of the mean based on de Alwis's work.

Kasiyah M. Junus

2006-11-01

115

A framework for fast probabilistic centroid-moment-tensor determination—inversion of regional static displacement measurements  

Science.gov (United States)

The determination of earthquake source parameters is an important task in seismology. For many applications, it is also valuable to understand the uncertainties associated with these determinations, and this is particularly true in the context of earthquake early warning (EEW) and hazard mitigation. In this paper, we develop a framework for probabilistic moment tensor point source inversions in near real time. Our methodology allows us to find an approximation to p(m|d), the conditional probability of source models (m) given observations (d). This is obtained by smoothly interpolating a set of random prior samples, using Mixture Density Networks (MDNs)-a class of neural networks which output the parameters of a Gaussian mixture model. By combining multiple networks as `committees', we are able to obtain a significant improvement in performance over that of a single MDN. Once a committee has been constructed, new observations can be inverted within milliseconds on a standard desktop computer. The method is therefore well suited for use in situations such as EEW, where inversions must be performed routinely and rapidly for a fixed station geometry. To demonstrate the method, we invert regional static GPS displacement data for the 2010 MW 7.2 El Mayor Cucapah earthquake in Baja California to obtain estimates of magnitude, centroid location and depth and focal mechanism. We investigate the extent to which we can constrain moment tensor point sources with static displacement observations under realistic conditions. Our inversion results agree well with published point source solutions for this event, once the uncertainty bounds of each are taken into account.

Käufl, Paul; Valentine, Andrew P.; O'Toole, Thomas B.; Trampert, Jeannot

2014-03-01

116

Finding the Beef: A Journalistic Summary Method for the Basic Writer.  

Science.gov (United States)

Intended to give basic students simultaneous practice in reading and writing with an emphasis on accuracy, conciseness, and precision, the "finding the beef" method centers itself on summaries of news events. The first step of the method is to supply students with the appropriate data blocks based on news events, preferably those relating to…

Madden, Thomas R.

117

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

118

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

119

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

120

Dynamic Charge Centroid on Data Retention of Double-Nanostructure Nonvolatile Memory  

Science.gov (United States)

Dynamic charge centroid on retention characteristics of nonvolatile memories with double nanostructures (DNSs), gadolinium oxide nanocrystal (Gd2O3-NC), and hafnium oxide charge-trapping layer (HfO2-CTL) was investigated. Compared with the conventional Gd2O3-NC memory, the DNS memories exhibited superior data retention. In addition, the DNS memory with thicker HfO2-CTL presented more charge loss because the trapped charge centroid was located close to the HfO2/tunneling layer interface. The tendency of charge loss was consistent with the dynamic charge centroid at the low-flat-band-voltage shift region, indicating that the charge centroid location was important for the data retention of DNS nonvolatile memories.

Wang, Jer-Chyi; Lin, Chih-Ting; Chen, Chia-Hsin; Huang, Po-Wei; Lai, Chao-Sung

2012-04-01

 
 
 
 
121

Measurements of ultrasonic backscattered spectral centroid shift from spine in vivo: methodology and preliminary results  

Science.gov (United States)

We have developed a technique to measure backscattered ultrasound from lumbar vertebrae using a commercial ultrasound scanner. The spectral centroid shift between the spine and reference phantom data is an index of attenuation within the spine. From measurements from 11 vertebrae, we found a correlation coefficient of r = -0.61 between spectral centroid shift and bone mineral density (BMD). This negative correlation is expected as denser, more highly attenuating bone would be expected to produce greater downshifts in spectral centroid. This is the first technique performing quantitative ultrasound measurements on trabecular bone in the spine. This study shows that (1) acquisition of ultrasonic backscatter data from human spine in vivo is feasible, and (2) spectral centroid shift exhibits a moderate negative correlation with BMD in accordance with expectations.

Wear, Keith A.; Garra, Brian S.; Pinet, Melanie C.; Felker, Steven; Mai, Jonathan

2003-05-01

122

Parallel shooting methods for finding steady state solutions to engine simulation models  

DEFF Research Database (Denmark)

Parallel single- and multiple shooting methods were tested for finding periodic steady state solutions to a Stirling engine model. The model was used to illustrate features of the methods and possibilities for optimisations. Performance was measured using simulation of an experimental data set as test case. A parallel speedup factor of 23 on 33 processors was achieved with multiple shooting. But fast transients at the beginnings of sub intervals caused significant overhead for the multiple shooting methods and limited the best speedup to 3.8 relative to the fastest sequential method: Single shooting with reduced dimension of the boundary value problem.

Andersen, Stig Kildegård; Thomsen, Per Grove

2007-01-01

123

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

124

A new method to find full complex roots of a complex dispersion equation for light propagation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new numerical method is presented to find full complex roots of a complex dispersion equation. For the application of the solution, the complex dispersion equation of a cylindrical metallic nanowire is investigated. By using this method, locus of Brewster angle, complex dispersion curves of Surface Plasmon Polaritons (SPPs) and complex bulk modes can be obtained in once calculation. Approximate analytical solution to the complex dispersion equation has also been derived to...

Wan, Li

2011-01-01

125

Particle-spring method for form finding grid shell structures consisting of flexible members:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper a general design method is described that can significantly reduce the effort needed for form finding grid shells consisting of flexible members. This design method is based on particle-spring models for simulating the behaviour of a grid shell during construction. Hereby, the stress limitations that follow from the material properties are taken into account to modify the grid shell geometry with a minimal deviation from a pre-defined target shape. It is demonstrated how a simpl...

2012-01-01

126

Possible method of finding the partial inelasticity coefficient K0 at superhigh energies  

International Nuclear Information System (INIS)

A method is proposed for finding the partial inelasticity coefficient K0 in individual events in hadron-nucleus collisions at superhigh energies. Its use ensures that the methodological errors are considerably smaller than in other methods. The value of K0 is found by measuring the fraction of the energy of the electron-nuclear cascade produced in dense matter by the primary hadron which is transferred to electron-photon showers and the energy going into nuclear disintegrations

1985-03-01

127

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

128

Application of a Root Finding Method for Tropospheric Ducting Produced by Trilinear Refractivity Profiles.  

Science.gov (United States)

Knowledge of whether or not all modes of consequence have been found is of paramount importance in numerical waveguide studies. A general root finding method (RFM), developed for vlf/lf propagation in the earth-ionosphere waveguide, locates all complex ze...

C. L. Goodhart R. A. Pappert

1977-01-01

129

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

Science.gov (United States)

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. PMID:18425214

Selaru, Florin M; Wang, Suna; Yin, Jing; Schulmann, Karsten; Xu, Yan; Mori, Yuriko; Olaru, Alexandru V; Sato, Fumiaki; Hamilton, James P; Abraham, John M; Schneider, Paul; Greenwald, Bruce D; Brabender, Jan; Meltzer, Stephen J

2007-01-01

130

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

1990-10-15

131

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.

132

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

133

A method for finding bounds on critical values for non-attractive interacting particle systems  

International Nuclear Information System (INIS)

The method is to use a computer to find a function for the process that always has negative expectation by considering all relevant configurations of 0's and 1's at the boundary of a finite process in one dimension. It is shown that a branching annihilating random walk will die out if the diffusion parameter ? is greater than 0.176. The method may also be applied to attractive processes, and is used for the contact process in one dimension obtaining the same values as Ziezold and Grillenberger (1988) for up to 10 places in from the boundaries. (author)

1998-10-16

134

A new method of finding all Roots of simple quaternionic polynomials  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Feng, Lianggui; Zhao, Kaiming

2011-01-01

135

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 speakerâ??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

136

SAFT Based Imaging and Centroid Technique for Classification of UT Signals from the Steam Generator of a Nuclear Power Plant  

International Nuclear Information System (INIS)

Many technical methods are used for nondestructive testing field for solid materials. Among those, ultrasonic inspection methods are widely used and one of the popular methods involves the extraction of an appropriate set of features followed by the use of a neural network for the classification of the signals in the feature space. This paper describes an approach which uses LMS method to determine the coordinates of the ultrasonic probe followed by the use of SAFT with centroid technique to estimate the location of the ultrasonic reflector. The method is employed for classifying UT-NDE signals from the steam generator tubes in a nuclear power plant. The classification results are presented for the ultrasonic signals from cracks and deposits within steam generator tubes.

2008-06-01

137

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

138

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

Directory of Open Access Journals (Sweden)

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

139

Collective Centroid Oscillations as an Emittance Preservation Diagnostic in Linear Collider Linacs  

Science.gov (United States)

Transverse bunch centroid oscillations, induced at operating beam currents at which transverse wakefields are substantial, and observed at Beam Position Monitors, are sensitive to the actual magnetic focusing, energy gain, and rf phase profiles in a linac, and are insensitive to misalignments and jitter sources. In the `pulse-stealing' set-up implemented at the SLC, they thus allow the frequent monitoring of the stability of the in-place emittance growth inhibiting or mitigating measures---primarily the energy scaled magnetic lattice and the rf phases necessary for BNS damping---independent of the actual emittance growth as driven by misalignments and jitter. We have developed a physically based analysis technique to meaningfully reduce this data. Oscillation beta-beating is a primary indicator of beam energy errors; shifts in the `invariant' amplitude reflect differential internal motion along the longitudinally extended bunch and thus are a sensitive indicator of the real rf phases in the machine; shifts in betatron phase advance contain corroborative information sensitive to both effects. Examples from initial SLC applications illustrate the method.

Adolphsen, C. E.; Bane, K. L. F.; Spence, W. L.; Woodley, M. D.

1997-05-01

140

The effect of event shape on centroiding in photon counting detectors  

International Nuclear Information System (INIS)

High resolution, CCD readout, photon counting detectors employ simple centroiding algorithms for defining the spatial position of each detected event. The accuracy of centroiding is very dependent upon a number of parameters including the profile, energy and width of the intensified event. In this paper, we provide an analysis of how the characteristics of an intensified event change as the input count rate increases and the consequent effect on centroiding. The changes in these parameters are applied in particular to the MIC photon counting detector developed at UCL for ground and space based astronomical applications. This detector has a maximum format of 3072x2304 pixels permitting its use in the highest resolution applications. Individual events, at light level from 5 to 1000k events/s over the detector area, were analysed. It was found that both the asymmetry and width of event profiles were strongly dependent upon the energy of the intensified event. The variation in profile then affected the centroiding accuracy leading to loss of resolution. These inaccuracies have been quantified for two different 3 CCD pixel centroiding algorithms and one 2 pixel algorithm. The results show that a maximum error of less than 0.05 CCD pixel occurs with the 3 pixel algorithms and 0.1 CCD pixel for the 2 pixel algorithm. An improvement is proposed by utilising straight pore MCPs in the intensifier and a 70 ?m air gap in front of the CCD. ((orig.))

1994-09-01

 
 
 
 
141

Light centroid shifts in observed stars due to microlensing by intervening disk stars  

CERN Document Server

The light centroid shifts caused by microlensing due to intervening stars for given source objects is investigated, and their relevance to the upcoming astrometric space missions, such as SIM and GAIA, are discussed. It turns out that, despite the effect of the sun and the planets, the dominant contribution comes from the stars in the galactic disk. The probability that a disk star introduces a centroid shift larger than 0.7 micro-arcsec at a given time reaches 100% for a source towards the Baade's window, while this probability is about 2% for a centroid shifts larger than 10 micro-arcsec. However, this contribution of disk stars to the centroid shift is not likely to vary much during the observation time of a typical photometric microlensing event; so it is possible to unambiguously observe the variation of the centroid shift by the lens object which lead to the photometric signature. On the other hand, a survey using astrometric detection can be used to infer information about the disk stars, a population ...

Dominik, M; Dominik, Martin; Sahu, Kailash C.

1998-01-01

142

New Method for Finding an Optimal Solution to Quadratic Programming Problems  

Directory of Open Access Journals (Sweden)

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

143

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 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. 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 the STRIPACK-based approaches, the new parallel algorithm results in significant speedups for the construction of spherical centroidal Voronoi tessellations.

D. W. Jacobsen

2013-02-01

144

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

145

Minima Hopping Accelerated Path Search: An Efficient Method for Finding Complex Chemical Reaction Pathways  

CERN Document Server

Based on Minima Hopping and its capabilities of exploring potential energy surfaces we have developed Minima Hopping Accelerated Path Search (MHAPS) which is a novel algorithm for efficiently finding the reaction paths of complex chemical reactions by sampling collections of energetically low-lying minima and first order saddle points of potential energy surfaces. For this new reaction path search method we developed a highly reliable approach for computing saddle points which is based on the idea of a bar rolling downwards the potential energy landscape. For Lennard-Jones benchmark systems, Minima Hopping Accelerated Path Search was compared to a known mode-following based approach for sampling collections of minima and first order transition states. Although we used a stabilized mode-following technique that reliably allows to follow distinct directions that are defined by the eigenvectors of the Hessian matrix, we observed that Minima Hopping Accelerated Path Search is far superior in finding lowest-barrie...

Schaefer, Bastian; Amsler, Maximilian; Goedecker, Stefan

2014-01-01

146

Minima hopping guided path search: An efficient method for finding complex chemical reaction pathways.  

Science.gov (United States)

The Minima Hopping global optimization method uses physically realizable molecular dynamics moves in combination with an energy feedback that guarantees the escape from any potential energy funnel. For the purpose of finding reaction pathways, we argue that Minima Hopping is particularly suitable as a guide through the potential energy landscape and as a generator for pairs of minima that can be used as input structures for methods capable of finding transition states between two minima. For Lennard-Jones benchmark systems we compared this Minima Hopping guided path search method to a known approach for the exploration of potential energy landscapes that is based on deterministic mode-following. Although we used a stabilized mode-following technique that reliably allows to follow distinct directions when escaping from a local minimum, we observed that Minima Hopping guided path search is far superior in finding lowest-barrier reaction pathways. We, therefore, suggest that Minima Hopping guided path search can be used as a simple and efficient way to identify energetically low-lying chemical reaction pathways. Finally, we applied the Minima Hopping guided path search approach to 75-atom and 102-atom Lennard-Jones systems. For the 75-atom system we found pathways whose highest energies are significantly lower than the highest energy along the previously published lowest-barrier pathway. Furthermore, many of these pathways contain a smaller number of intermediate transition states than the previously publish lowest-barrier pathway. In case of the 102-atom system Minima Hopping guided path search found a previously unknown and energetically low-lying funnel. PMID:24907985

Schaefer, Bastian; Mohr, Stephan; Amsler, Maximilian; Goedecker, Stefan

2014-06-01

147

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

Directory of Open Access Journals (Sweden)

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

148

Fast simulators for satellite cloud optical centroid pressure retrievals, 1. evaluation of OMI cloud retrievals  

Directory of Open Access Journals (Sweden)

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. A fast simulator is desirable in order 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 a fast simulator that provides 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 the fast simulator 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 in order 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, and the fact that CloudSat only observes a relatively small fraction of OMI pixel.

J. Joiner

2011-10-01

149

Centroid Position as a Function of Total Counts in a Windowed CMOS Image of a Point Source  

Energy Technology Data Exchange (ETDEWEB)

We obtained 960,200 22-by-22-pixel windowed images of a pinhole spot using the Teledyne H2RG CMOS detector with un-cooled SIDECAR readout. We performed an analysis to determine the precision we might expect in the position error signals to a telescope's guider system. We find that, under non-optimized operating conditions, the error in the computed centroid is strongly dependent on the total counts in the point image only below a certain threshold, approximately 50,000 photo-electrons. The LSST guider camera specification currently requires a 0.04 arcsecond error at 10 Hertz. Given the performance measured here, this specification can be delivered with a single star at 14th to 18th magnitude, depending on the passband.

Wurtz, R E; Olivier, S; Riot, V; Hanold, B J; Figer, D F

2010-05-27

150

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

Energy Technology Data Exchange (ETDEWEB)

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.

BURKARDT, JOHN; GUNZBURGER, MAX; PETERSON, JANET; BRANNON, REBECCA M.

2002-02-01

151

Measurements of ultrasonic backscattered spectral centroid shift from spine in vivo: methodology and preliminary results.  

Science.gov (United States)

Ultrasonic backscatter measurements from vertebral bodies (L3 and L4) in nine women were performed using a clinical ultrasonic imaging system. Measurements were made through the abdomen. The location of a vertebra was identified from the bright specular reflection from the vertebral anterior surface. Backscattered signals were gated to isolate signal emanating from the cancellous interiors of vertebrae. The spectral centroid shift of the backscattered signal, which has previously been shown to correlate highly with bone mineral density (BMD) in human calcaneus in vitro, was measured. BMD was also measured in the nine subjects' vertebrae using a clinical bone densitometer. The correlation coefficient between centroid shift and BMD was r = -0.61. The slope of the linear fit was -160 kHz / (g/cm(2)). The negative slope was expected because the attenuation coefficient (and therefore magnitude of the centroid downshift) is known from previous studies to increase with BMD. The centroid shift may be a useful parameter for characterizing bone in vivo. PMID:18723270

Garra, Brian S; Locher, Melanie; Felker, Steven; Wear, Keith A

2009-01-01

152

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

153

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

154

A VLSI centroid extractor for real-time target tracking applications  

Energy Technology Data Exchange (ETDEWEB)

The Automatic Centroid Extractor (ACE) is a CMOS VLSI chip that performs target extraction and centroiding functions for an extensible real-time target tracking system. Contiguous pixels whose intensities exceed a given threshold are grouped into separate objects, and three weighted sums of pixel intensities that can rapidly be converted to the target centroid and average intensity are calculated for each object. Proper assignment of contiguous pixels to their respective objects is guaranteed for all convex shapes and most concave shapes. Data for a NxM pixel image is processed in raster scan format with a maximum value of 1024 for N and M. ACE can process in excess of 500 objects per frame and accepts input at up to 20 Megapixels per second. To increase the flexibility of the chip, arbitrary circular regions of the image can be masked so that they do not enter the target extraction process. This allows any set of fixed targets to be ignored if they are not of interest. The chip is a full custom design containing approximately 200,000 transistors and is being fabricated using Hewlett Packard's CMOS40 process. The ACE chip interfaces directly to the Inmos Transputer over a serial link. The communication link is used to select the threshold and to specify the circular regions of the image that will be masked, as well as to transfer target centroids and status information. 2 refs., 2 figs.

Axelrod, T.S.; Tassinari, T.F.

1989-08-21

155

Study of finding out uranium deposit with geophysical methods at Zhongdong district Onyuan county Guangdong province  

International Nuclear Information System (INIS)

The soil natural thermoluminescence measurement and radon survey were chosen, whose penetrability is stronger, and their applied effects were studied in prospecting uranium deposit at Xiazhuang granite area. The 236 stations were measured respectively with these two methods at Zhongdong district Ongyuan county Guangdong province. The research results show that: 1. There are good effects which fractured zones were found out with radon survey. 2. The soil natural thermoluminescence measurement is one of the cumulative measurement methods. It can obviously respond the projected position of uranium deposit of intersected point type. 3. The sensitivity, stability and reappearance of the soil natural thermoluminescence is good, and it was less affected by human activity on the surface. The measured anomalies can reflect the variety of the radioactive field, so amplitude and width of anomalies can basically respond the distribution of uranium ore body. The problems to be solved in the future are: If the rocks above the 'intersection point type' uranium deposits are relatively intact, how much depth can it be found out with soil natural thermoluminescence method? A set of nuclear geophysical prospecting pattern on the different types of uranium deposits in Xiazhuang uranium ore field should be summarized so that they can be used to find out uranium deposits in granite area in the future. (authors)

2008-01-01

156

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

Directory of Open Access Journals (Sweden)

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

157

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

158

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

159

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

CERN Document Server

The use of Adaptive Optics in Extremely Large Telescopes brings new challenges, one of which is the treatment of Shack-Hartmann Wavefront sensors images. When using this type of sensors in conjunction with laser guide stars for sampling the pupil of telescopes with 30+ m in diameter, 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 Matched Filter have been considered as the best technique to compute the centroid of elongated spots, however they are not good at coping with the effect of a variation in the Sodium profile. In this work we propose a new technique using artificial neural networks, which take advantage of the neural network's ability to cope with changing conditions, outperforming existing techniques in this context. We have developed comprehensive simulations to explore this technique and compare it with existing algorithms.

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

2014-01-01

160

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 validat...

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

2012-01-01

 
 
 
 
161

Fast simulators for satellite cloud optical centroid pressure retrievals, 1. evaluation of OMI cloud retrievals  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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. A fast simulator is desirable in order 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 an...

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

2011-01-01

162

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...

Wu, Xia; Yu, Xiong; Jing, Hao

2011-01-01

163

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...

Xia Wu; Xiong Yu; Hao Jing

2011-01-01

164

Centroiding algorithms for high speed crossed-strip readout of microchannel plate detectors  

International Nuclear Information System (INIS)

Imaging microchannel plate (MCP) detectors with cross-strip (XS) readout anodes require centroiding algorithms to determine the location of the amplified charge cloud from the incident radiation, be it photon or particle. We have developed a massively parallel XS readout electronic system that employs an amplifier and ADC for each strip and uses this digital data to calculate the centroid of each event in real time using a field programmable gate array (FPGA). Doing the calculations in real time in the front end electronics using an FPGA enables a much higher input event rate, nearly two orders of magnitude faster by avoiding the bandwidth limitations of the raw data transfer to a computer. We report on our detailed efforts to optimize the algorithms used on both 18 and 40 mm diameter XS MCP detector with strip pitch of 640 ?m and readout with multiple 32 channel 'Preshape32' ASIC amplifiers (developed at Rutherford Appleton Laboratory). Each strip electrode is continuously digitized to 12 bits at 50 MHz with all 64 digital channels (128 for the 40 mm detector) transferred to a Xilinx Virtex 5 FPGA. We describe how events are detected in the continuous data stream and then multiplexed into firmware modules that spatially and temporally filter and weight the input after applying offset and gain corrections. We will contrast a windowed 'center of gravity' algorithm to a convolution with a special centroiding kernel in terms of resolution and distortion and show results with1 MHz.

2011-05-01

165

Statistical Properties of Line Centroid Velocity Increments in the rho Ophiuchi Cloud  

Science.gov (United States)

We present a comparison of histograms of CO (2-1) line centroid velocity increments in the rho Ophiuchi molecular cloud with those computed for spectra synthesized from a three-dimensional, compressible, but non-starforming and non-gravitating hydrodynamic simulation. Histograms of centroid velocity increments in the rho Ophiuchi cloud show clearly non-Gaussian wings, similar to those found in histograms of velocity increments and derivatives in experimental studies of laboratory and atmospheric flows, as well as numerical simulations of turbulence. The magnitude of these wings increases monotonically with decreasing separation, down to the angular resolution of the data. This behavior is consistent with that found in the phase of the simulation which has most of the properties of incompressible turbulence. The time evolution of the magnitude of the non-Gaussian wings in the histograms of centroid velocity increments in the simulation is consistent with the evolution of the vorticity in the flow. However, we cannot exclude the possibility that the wings are associated with the shock interaction regions. Moreover, in an active starforming region like the rho Ophiuchi cloud, the effects of shocks may be more important than in the simulation. However, being able to identify shock interaction regions in the interstellar medium is also important, since numerical simulations show that vorticity is generated in shock interactions.

Lis, D. C.; Keene, Jocelyn; Li, Y.; Phillips, T. G.; Pety, J.

1998-01-01

166

Inclusion of inversion symmetry in centroid molecular dynamics: A possible avenue to recover quantum coherence  

International Nuclear Information System (INIS)

Inversion symmetry is included in the operator formulation of the centroid molecular dynamics (CMD). This work involves the development of a symmetry-adapted CMD (SA-CMD), here particularly for symmetrization and antisymmetrization projections. A symmetry-adapted quasidensity operator, as defined by Blinov and Roy [J. Chem. Phys. 115, 7822 (2001)], is employed to obtain the centroid representation of quantum mechanical operators. Numerical examples are given for a single particle confined to one-dimensional symmetric quartic and symmetric double-well potentials. Two SA-CMD simulations are performed separately for both projections, and centroid position autocorrelation functions are obtained. For each projection, the quality of the approximation as well as the accuracy are similar to those of regular CMD. It is shown that individual trajectories from two separate SA-CMD simulations can be properly combined to recover trajectories for Boltzmann statistics. Position autocorrelation functions are compared to the exact quantum mechanical ones. This explicit account of inversion symmetry provides a qualitative improvement on the conventional CMD approach and allows the recovery of some quantum coherence

2006-10-28

167

Inclusion of inversion symmetry in centroid molecular dynamics: a possible avenue to recover quantum coherence.  

Science.gov (United States)

Inversion symmetry is included in the operator formulation of the centroid molecular dynamics (CMD). This work involves the development of a symmetry-adapted CMD (SA-CMD), here particularly for symmetrization and antisymmetrization projections. A symmetry-adapted quasidensity operator, as defined by Blinov and Roy [J. Chem. Phys. 115, 7822 (2001)], is employed to obtain the centroid representation of quantum mechanical operators. Numerical examples are given for a single particle confined to one-dimensional symmetric quartic and symmetric double-well potentials. Two SA-CMD simulations are performed separately for both projections, and centroid position autocorrelation functions are obtained. For each projection, the quality of the approximation as well as the accuracy are similar to those of regular CMD. It is shown that individual trajectories from two separate SA-CMD simulations can be properly combined to recover trajectories for Boltzmann statistics. Position autocorrelation functions are compared to the exact quantum mechanical ones. This explicit account of inversion symmetry provides a qualitative improvement on the conventional CMD approach and allows the recovery of some quantum coherence. PMID:17092059

Huh, Yoonjung; Roy, Pierre-Nicholas

2006-10-28

168

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

Directory of Open Access Journals (Sweden)

Full Text Available 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.

D. W. Jacobsen

2013-08-01

169

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

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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

170

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.

2010-01-01

171

The expanded FindCore method for identification of a core atom set for assessment of protein structure prediction.  

Science.gov (United States)

Maximizing the scientific impact of NMR-based structure determination requires robust and statistically sound methods for assessing the precision of NMR-derived structures. In particular, a method to define a core atom set for calculating superimpositions and validating structure predictions is critical to the use of NMR-derived structures as targets in the CASP competition. FindCore (Snyder and Montelione, Proteins 2005;59:673-686) is a superimposition independent method for identifying a core atom set and partitioning that set into domains. However, as FindCore optimizes superimposition by sensitively excluding not-well-defined atoms, the FindCore core may not comprise all atoms suitable for use in certain applications of NMR structures, including the CASP assessment process. Adapting the FindCore approach to assess predicted models against experimental NMR structures in CASP10 required modification of the FindCore method. This paper describes conventions and a standard protocol to calculate an "Expanded FindCore" atom set suitable for validation and application in biological and biophysical contexts. A key application of the Expanded FindCore method is to identify a core set of atoms in the experimental NMR structure for which it makes sense to validate predicted protein structure models. We demonstrate the application of this Expanded FindCore method in characterizing well-defined regions of 18 NMR-derived CASP10 target structures. The Expanded FindCore protocol defines "expanded core atom sets" that match an expert's intuition of which parts of the structure are sufficiently well defined to use in assessing CASP model predictions. We also illustrate the impact of this analysis on the CASP GDT assessment scores. PMID:24327305

Snyder, David A; Grullon, Jennifer; Huang, Yuanpeng J; Tejero, Roberto; Montelione, Gaetano T

2014-02-01

172

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

173

Finding Discontinuous Solutions to the Differential-Difference Equations by the Homotopy Analysis Method  

International Nuclear Information System (INIS)

An analytic method, namely the homotopy analysis method, is applied to nonlinear problems with discontinuity governed by the differential-difference equation. Purely analytic solutions are given for nonlinear problems with discontinuity with a global convergence. This method provides a new analytical approach to solve nonlinear problems with discontinuity. Comparisons are made between the results of the proposed method and the exact solutions. The results reveal that the proposed method is very effective and convenient

2013-02-01

174

Finding Discontinuous Solutions to the Differential-Difference Equations by the Homotopy Analysis Method  

Science.gov (United States)

An analytic method, namely the homotopy analysis method, is applied to nonlinear problems with discontinuity governed by the differential-difference equation. Purely analytic solutions are given for nonlinear problems with discontinuity with a global convergence. This method provides a new analytical approach to solve nonlinear problems with discontinuity. Comparisons are made between the results of the proposed method and the exact solutions. The results reveal that the proposed method is very effective and convenient.

Zou, Li; Zou, Dong-Yang; Wang, Zhen; Zong, Zhi

2013-02-01

175

Establishing the soft and hard tissue area centers (centroids) for the skull and introducing a newnon-anatomical cephalometric line  

International Nuclear Information System (INIS)

The purpose of this study was to demonstrate how to establish the area center (centroid) of both the soft and hard tissues of the outline of the lateral cephalometric skull image, and to introduce the concept of a new non-anatomical centroid line. Lateral cephalometric radiographs, size 12 x 14 inch, of fifty seven adult subjects were selected based on their pleasant, balanced profile, Class I skeletal and dental relationship and no major dental malocclusion or malrelationship. The area centers (centroids) of both soft and hard tissue skull were practically established using a customized software computer program called the m-file. Connecting the two centers introduced the concept of a new non-anatomical soft and hard centroids line. (author)

2008-01-01

176

A New Homotopy Analysis Method for Finding the Exact Solution of Systems of Partial Differential Equations  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, the application of a new homotopy analysis method presented for obtaining solutions of systems of non-linear partial differential equations. Theoretical considerations are discussed. To explain the capability and reliability of the new method some examples are provided. The results show that the new technique is very effective and convenient and comparison of the obtained solutions of this new method with those of applying homotopy analysis method have high accuracy.

M. Matinfar

2012-06-01

177

A New Homotopy Analysis Method for Finding the Exact Solution of Systems of Partial Differential Equations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, the application of a new homotopy analysis method presented for obtaining solutions of systems of non-linear partial differential equations. Theoretical considerations are discussed. To explain the capability and reliability of the new method some examples are provided. The results show that the new technique is very effective and convenient and comparison of the obtained solutions of this new method with those of applying homotopy analysis method have high accuracy.

2012-01-01

178

Moving Domestic Robotics Control Method Based on Creating and Sharing Maps with Shortest Path Findings and Obstacle Avoidance  

Directory of Open Access Journals (Sweden)

Full Text Available Control method for moving robotics in closed areas based on creation and sharing maps through shortest path findings and obstacle avoidance is proposed. Through simulation study, a validity of the proposed method is confirmed. Furthermore, the effect of map sharing among robotics is also confirmed together with obstacle avoidance with cameras and ultrasonic sensors.

Kohei Arai

2013-02-01

179

CT findings of pancreatic carcinoma. Evaluation with the combined method of early enhancement CT and high dose enhancement CT  

International Nuclear Information System (INIS)

Computed tomographic (CT) findings of pancreatic ductal adenocarcinoma were studied with the combined method of early enhancement CT and high dose enhancement CT in 72 carcinomas. Common Findings were change in pancreatic contour, abnormal attenuation in a tumor and dilatation of the main pancreatic duct. The incidence of abnormal attenuation and dilatation of the main pancreatic duct and bile duct was constant regardless of tumor size. The finding of hypoattenuation at early enhancement CT was most useful for demonstrating a carcinoma. However, this finding was negative in ten cases, five of which showed inhomogenous hyperattenuation at high dose enhancement CT. The detection of change in pancreatic contour and dilatation of the main pancreatic duct was most frequent at high dose enhancement CT. The finding of change in pancreatic contour and/or abnormal attenuation in a tumor could be detected in 47 cases at plain CT, 66 at early enhancement CT and 65 at high dose enhancement CT. Since the four cases in which neither finding was detected by any CT method showed dilatated main pancreatic duct, there was no case without abnormal CT findings. This combined CT method will be a reliable diagnostic technique in the imaging of pancreatic carcinoma. (author)

1995-06-01

180

Methods, Findings, and History in Attitude-Behavior Research: A Rejoinder to Hanson.  

Science.gov (United States)

Reviews Hanson's findings that laboratory research tends to demonstrate a positive correlation between attitudes and behavior while field research does not. This article, by adding date of publication, shows that the trend over time, presumably because of improved methodology, is toward more positive correlations in both settings. (Author/JAC)

Piliavin, Jane Allyn

1981-01-01

 
 
 
 
181

Functional minimization method addressed to the vacuum finding for an arbitrary driven quantum oscillator  

CERN Multimedia

The old problem exists for a driven (time-dependent) quantum oscillator: to differ the true vacuum state from the squeezed one. We suggest finding the true vacuum state by minimization of the functional containing the difference of the potential and kinetic energies of oscillator. Analytical and numerical examples confirming this offer are considered.

Anischenko, S V; Kalashnikov, V L

2008-01-01

182

A General Family of Fifth-Order Methods for Finding Simple Roots of Nonlinear Equations  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a new fifth-order family of methods free from second derivative is obtained. The new iterative family contains the King’s, which is one of the most well-known family of methods for solving nonlinear equations, and some other known methods as its particular case. To illustrate the efficiency and performance of proposed family, several numerical examples are presented. Numerical results illustrate better efficiency and performance of the presented methods in comparison with the other compared fifth-order methods. Therefore, the proposed family can be effectively used for solving nonlinear equations.

Behzad GHANBARI

2012-06-01

183

Mechanical form-Finding of the Timber Fabric Structures with Dynamic Relaxation Method  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Timber Fabric structures (TFS) initiate from a correspondence between textile principles and recent industrial developments in producing cross laminated timber panels. Several individual timber strips are interlaced according to a pattern and result in an innovative space structure. The obtained three-dimensional geometry can be regarded as the relaxed configuration of deformed panels under the imposed boundary conditions. We herein propose a form-finding procedure, which reproduces this def...

2013-01-01

184

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

185

A Method for Finding Structured Sparse Solutions to Non-negative Least Squares Problems with Applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Demixing problems in many areas such as hyperspectral imaging and differential optical absorption spectroscopy (DOAS) often require finding sparse nonnegative linear combinations of dictionary elements that match observed data. We show how aspects of these problems, such as misalignment of DOAS references and uncertainty in hyperspectral endmembers, can be modeled by expanding the dictionary with grouped elements and imposing a structured sparsity assumption that the combina...

Esser, Ernie; Lou, Yifei; Xin, Jack

2013-01-01

186

Variation of centroid distribution of magnetized layer in the Philippine Sea deduced from spectral analysis of marine magnetic anomalies  

Science.gov (United States)

A new global magnetic anomaly data was released [Quesnel et al, in press]. We used this CM4-corrected [Comprehensive Model 4; Sabaka et al., 2004], cleaned and leveled data to clarify the three-dimensional crustal magnetic structure of the Philippine Sea. One-dimensional and two-dimensional spectral analyses of marine magnetic anomalies [Makino et al., 1988; Tanaka, 2008] were applied to estimate the centroid depths of crustal magnetic layers (Zo) to constrain the lithospheric structure. There are some limitations in these methods: There are not enough data available to be applied in estimating Zo for one-dimensional spectral analysis, and the two-dimensional spectral analysis method remains still controversial. However, both methods give consistent results, and the obtained Zo distribution provides a comprehensive view of regional-scale features, which are well correlated with acoustic basement structures [Higuchi et al., 2007] and known tectonic regime. The results show occurrence of shallow magnetic layer areas with approximately less than 10 km in the Shikoku Basin. It also shows variations in deep and shallow magnetic layer areas in the Amami-Daito Province, which corresponds to spatial variation of the crustal thickness and acoustic basement structures. It is expected that Zo combined with multidisciplinary data should help to infer geophysical and geological information.

Tanaka, A.; Ishihara, T.

2009-04-01

187

Relative entropy of cone measures and $L_p$ centroid bodies  

CERN Multimedia

Let $K$ be a convex body in $\\mathbb R^n$. We introduce a new affine invariant, which we call $\\Omega_K$, that can be found in three different ways: as a limit of normalized $L_p$-affine surface areas, as the relative entropy of the cone measure of $K$ and the cone measure of $K^\\circ$, as the limit of the volume difference of $K$ and $L_p$-centroid bodies. We investigate properties of $\\Omega_K$ and of related new invariant quantities. In particular, we show new affine isoperimetric inequalities and we show a "information inequality" for convex bodies.

Paouris, Grigoris

2009-01-01

188

Centers and centroids of the cone-beam projection of a ball  

International Nuclear Information System (INIS)

In geometric calibration of cone-beam (CB) scanners, point-like marker objects such as small balls are imaged to obtain positioning information from which the unknown geometric parameters are extracted. The procedure is sensitive to errors in the positioning information, and one source of error is a small bias which can occur in estimating the detector locations of the CB projections of the centers of the balls. We call these detector locations the center projections. In general, the CB projection of a ball of uniform density onto a flat detector forms an ellipse. Inside the ellipse lie the center projection M, the ellipse center C and the centroid G of the intensity values inside the ellipse. The center projection is invariably estimated from C or G which are much easier to extract directly from the data. In this work, we quantify the errors incurred in using C or G to estimate M. We prove mathematically that the points C, G, M and O are always distinct and lie on the major axis of the ellipse, where O is the detector origin, defined as the orthogonal projection of the cone vertex onto the detector. (The ellipse can only degenerate to a circle if the ball is along the direct line of sight to O, and in this case all four points coincide.) The points always lie in the same order: O, M, G, C which establishes that the centroid has less geometric bias than the ellipse center for estimating M. However, our numerical studies indicate that the centroid bias is only 20% less than the ellipse center bias so the benefit in using centroid estimates is not substantial. For the purposes of quantifying the bias in practice, we show that the ellipse center bias ||CM|| can be conveniently estimated by eA/(? f-tilde) where A is the area of the elliptical projection, e is the eccentricity of the ellipse and f-tilde is an estimate of the focal length of the system. Finally, we discuss how these results are affected by physical factors such as beam hardening, and indicate extensions to balls of non-uniform density.

2011-12-07

189

METHOD FOR ESTIMATING METHANE EMISSIONS FROM UNDERGROUND COAL MINES: PRELIMINARY FINDINGS  

Science.gov (United States)

The paper discusses the development of an improved method for estimating global methane (CH4) emissions from underground coal mining. ince emissions data presently not available for surface mines, this method is currently restricted to underground mines. The EPA has embarked on a...

190

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

191

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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. 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...

Delorme, Philippe; Willott, Chris; Forveille, Thierry; Delfosse, Xavier; Reyle?, Ce?line; Bertin, Emmanuel; Albert, Loic; Artigau, Etienne; Robin, Annie; Allard, France; Doyon, Rene; Hill, Gary

2008-01-01

192

A Hybrid Method for Fast Finding the Reduct with the Best Classification Accuracy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Usually a dataset has a lot of reducts finding all of which is known to be an NP hard problem. On the other hand, different reducts of a dataset may provide different classification accuracies. Usually, for every dataset, there is only a reduct with the best classification accuracy to obtain this best one, firstly we obtain the group of attributes that are dominant for the given dataset by using the decision tree algorithm. Secondly we complete this group up to reducts by using discernibi...

Hacibeyoglu, M.; Arslan, A.; Kahramanli, S.

2013-01-01

193

FINDING CRITICAL BUCKLING LOAD OF RECTANGULAR PLATE USING INTEGRATED FORCE METHOD  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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. Mat...

2012-01-01

194

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...

2011-01-01

195

Finding the Exact Solution of Special Nonlinear Partial Differential Equations by Homotopy Analysis Method  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, the homotopy analysis method was used to solve nonlinear parabolic-hyperbolic partial differential equations. Examples are presented here to show the usability of the method for such equations. The results show that the HAM is very effective and convenient and that the obtained solutions of HAM have high accuracy.doi:10.14456/WJST.2014.36

Mashallah MATINFAR

2014-01-01

196

DiffCoEx: a simple and sensitive method to find differentially coexpressed gene modules  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Large microarray datasets have enabled gene regulation to be studied through coexpression analysis. While numerous methods have been developed for identifying differentially expressed genes between two conditions, the field of differential coexpression analysis is still relatively new. More specifically, there is so far no sensitive and untargeted method to identify gene modules (also known as gene sets or clusters that are differentially coexpressed between two conditions. Here, sensitive and untargeted means that the method should be able to construct de novo modules by grouping genes based on shared, but subtle, differential correlation patterns. Results We present DiffCoEx, a novel method for identifying correlation pattern changes, which builds on the commonly used Weighted Gene Coexpression Network Analysis (WGCNA framework for coexpression analysis. We demonstrate its usefulness by identifying biologically relevant, differentially coexpressed modules in a rat cancer dataset. Conclusions DiffCoEx is a simple and sensitive method to identify gene coexpression differences between multiple conditions.

Breitling Rainer

2010-10-01

197

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

198

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

CERN Document Server

Gravitational lens models with negative convergence (surface mass density projected onto the lens plane) inspired by modified gravity theories, exotic matter and energy have been recently examined to discuss possible demagnification of images and gravitational lensing shear, in such a way that a static and spherically symmetric modified spacetime metric depends on the inverse distance to the power of positive $n$ ($n=1$ for Schwarzschild metric, $n=2$ for Ellis wormhole) in the weak-field approximation [Kitamura, Nakajima and Asada, PRD 87, 027501 (2013), Izumi et al. to be published in PRD (2013)]. Some of the exotic lens models cause the attractive force on light rays like 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 l...

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

2013-01-01

199

A method to find tissue-specific novel sites of selective adenosine deamination  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Site-selective adenosine (A) to inosine (I) RNA editing by the ADAR enzymes has been found in a variety of metazoan from fly to human. Here we describe a method to detect novel site-selective A to I editing that can be used on various tissues as well as species. We have shown previously that there is a preference for ADAR2-binding to selectively edited sites over non-specific interactions with random sequences of double-stranded RNA. The method utilizes immunoprecipitation (IP) of intrinsic R...

Ohlson, Johan; Enstero?, Mats; Sjo?berg, Britt-marie; O?hman, Marie

2005-01-01

200

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

 
 
 
 
201

A simultaneous hit finding and timing method for pulse shape analysis of drift chamber signals  

International Nuclear Information System (INIS)

An algorithm for the analysis of the digitized signal waveform of drift chamber pulses is described which yields a good multihit resolution and an accurate drift time determination with little processing time. The method has been tested and evaluated with measured pulse shapes from the full size prototype of the OPAL central detector which were digitized by 100 MHz FADCs. (orig.)

1986-01-01

202

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

203

Preliminary Findings of a Format-based Foreign Language Teaching Method for School Children in the Basque Country.  

Science.gov (United States)

Describes the preliminary findings in the Basque Country of a project shared by four European countries to teach a second language or a foreign language to preschool and school-age children. The method used to teach the foreign language--English--is based on the use of dramatized formats. Examines level of language proficiency achieved with each…

Azpillaga, Beronika; Arzamendi, Jesus; Etxeberria, Feli; Garagorri, Xabier; Lindsay, Diana; Joaristi, Luis

2001-01-01

204

Dating of inkpad seals using the extraction rate method: preliminary findings.  

Science.gov (United States)

Inkpad seals are often placed on important documents, and determining the date when a seal was affixed can be important to assess the authenticity of a document. In this study, three different brands of inkpads and four different types of paper were used to make diachronic samples of the seals. A double-solvent extraction method was employed to date the inkpad seals by comparing extraction rates with inks of known age. Cyclohexane was selected as a weak solvent, and chlorobenzene was selected as a strong solvent. After testing, curves were created to show the relationship between the extraction percentage of ink and the date of the seals. The experimental results showed that the extraction rate method was applicable for the relative dating of inkpad seals in some cases where the seal was placed on the document within 6 months. PMID:24502316

Li, Biao; Bai, Feng; Mu, Huayan; Bao, Ren

2014-05-01

205

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

206

The relationship between vocational interests and intelligence: Do findings generalize across different assessment methods?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this study was to further explore the relationship between vocational interests and intelligence. There is some evidence in literature on the stable relationships between vocational interests and intelligence (cf. Ackerman & Heggestad, 1997). It should be noted that the majority of the previous studies have only used questionnaires for the assessment of vocational interests. Thus, it is of interest whether the results are also stable when different assessment methods are used. Ther...

Proyer, Rene T.

2007-01-01

207

Combined Calibration Method and its Realization for Direction Finding Antenna Systems with Patch Antennas  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A novel radio channel compensation method aiming to give optimal calibration for microstrip antenna array systems is presented in this paper, realized for an actual DOA measurement antenna system using microstrip antennas to sample the electromagnetic field, operating at 4.5GHz. This new approach considers mismatch between antennas and channel RF ports, channel transmission inequalities, and also decreases the effects of multipath propagation components of calibration reference signals by pla...

Magyar, A.; Miko, G.; Seller, R.

2007-01-01

208

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

International Nuclear Information System (INIS)

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, CTDIvol 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.)

2011-09-01

209

Adaptive Ant Colony Clustering Method Applied to Finding Closely Communicating Community  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 communicat...

Yan Liu; Lian Liu; Junyong Luo

2012-01-01

210

A new method to find a set of energetically optimal RNA secondary structures.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present a computer method to determine nucleic acid secondary structures. It is based on three steps: 1) the search for all possible helical regions relied on a mathematical approach derived from the convolution theorem; it uses a tetradimensional complex vector representation of the bases along the sequence; 2) a 'tree' search for a set of minimum free energy structures, by the aid of an approximate energy evaluation to reduce the computer time requirements; 3) the exact calculation and r...

Benedetti, G.; Santis, P.; Morosetti, S.

1989-01-01

211

Efficient Path Finding with the Sweep-Line Method using External Storage  

DEFF Research Database (Denmark)

The sweep-line method deletes states on-the-fly during state space exploration to reduce peak memory usage. This deletion of states prohibits the immediate generation of, e.g., an error-trace when the violation of a safety property is detected. We address this problem by combining the sweep-line method with storing a spanning tree of the explored state space in external storage on a magnetic disk. We show how this allows us to easily obtain paths in the state space, such as error-traces. A key property of the proposed technique is that it avoids searching in external storage during the state space exploration and gives the same reduction in peak memory usage as the stand-alone sweep-line method. We evaluate the proposed technique on a number of example systems, and compare its performance to a related technique. These practical experiments demonstrate how the suggested technique complements existing techniques based on using external storage.

Kristensen, Lars Michael; Mailund, Thomas

2003-01-01

212

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

213

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

2014-06-01

214

The use of multicriteria decision making methods to find the environmental costs of hydropower development alternatives  

International Nuclear Information System (INIS)

The conference paper deals with a decision support system (DSS) developed to find the costs of environmental goods. The system is based on multicriteria decision making and uses pairwise comparisons of two and two criteria. The criteria weights are calculated with linear regression. When one criterion is monetary, all criteria weights can be expressed in monetary units when the weights are known. The DSS has been tested on a hydropower project in the area of Sauda in Norway. To represent the decision makers, three panels each consisting of three persons were formed. The persons were selected from governmental agencies, the developers, the local environmental administration and a local politician. The DSS worked well with the panels. One problem was that impacts of hydropower projects are very site specific and also hard to quantify. Therefore, a considerable amount of time was used in creating a cognitive understanding of the issues involved and how they were represented by quantitative criteria. Some had also difficulties in accepting the principle of expressing environmental goods in monetary units. The results so far are preliminary. This research work is part of the Norwegian research programme Energy, Environment and Development. 3 refs., 4 figs., 2 tabs

1994-08-01

215

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 s...

2012-01-01

216

The relationship between vocational interests and intelligence: Do findings generalize across different assessment methods?  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this study was to further explore the relationship between vocational interests and intelligence. There is some evidence in literature on the stable relationships between vocational interests and intelligence (cf. Ackerman & Heggestad, 1997. It should be noted that the majority of the previous studies have only used questionnaires for the assessment of vocational interests. Thus, it is of interest whether the results are also stable when different assessment methods are used. Therefore, a nonverbal test was used in this study together with two questionnaires. Additionally, tests for general intelligence, verbal, numeric, and spatial ability, and memory were used. A sample of N = 138 persons was tested in a computerized setting. Results indicate that there is a positive relation between Realistic and Investigative interests and spatial ability. This result was found for both the questionnaires as well as the nonverbal test. Therefore, it can be assumed that this relation is stable for different assessment methods. The data is discussed with respect to current literature.

RENÉ T. PROYER

2006-12-01

217

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

Science.gov (United States)

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. PMID:15448187

Pedersen, Jakob Skou; Meyer, Irmtraud Margret; Forsberg, Roald; Simmonds, Peter; Hein, Jotun

2004-01-01

218

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

219

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

220

Is dark matter present in NGC4736? An iterative spectral method for finding mass distribution in spiral galaxies  

CERN Document Server

We present Iterative Spectral Method of reconstructing mass distribution in spiral galaxies in an infinitely thin axial symmetric disk approximation. The method, without extra assumptions and free parameters, overcomes all problems encountered in standard use of disk model and utilises only information that is available observationally. As an example we apply the method to the ringed Sab-type galaxy NGC4736 that breaks sphericity condition at larger radii. We find mass distribution in NGC4736 that agrees perfectly with its high resolution rotation curve (high resolution, however, is not a must in our method). Given the distribution one finds rotational velocity which is the same as the observed rotation curve (!). The obtained surface mass density is consistent with the I-band luminosity profile (M/L_I=0.7 in Solar units) and with the amount of hydrogen observed in outermost regions where rotation curve is not measured. In the framework of Newtonian gravitation, these findings put in question the presence of ...

Bratek, L; Kutschera, M; Bratek, Lukasz; Jalocha, Joanna; Kutschera, Marek

2006-01-01

 
 
 
 
221

Finding all the stationary points of a potential-energy landscape via numerical polynomial-homotopy-continuation method.  

Science.gov (United States)

The stationary points (SPs) of a potential-energy landscape play a crucial role in understanding many of the physical or chemical properties of a given system. However, unless they are found analytically, no efficient method is available to obtain all the SPs of a given potential. We present a method, called the numerical polynomial-homotopy-continuation method, which numerically finds all the SPs, and is embarrassingly parallelizable. The method requires the nonlinearity of the potential to be polynomial-like, which is the case for almost all of the potentials arising in physical and chemical systems. We also certify the numerically obtained SPs so that they are independent of the numerical tolerance used during the computation. It is then straightforward to separate out the local and global minima. As a first application, we take the XY model with power-law interaction, which is shown to have a polynomial-like nonlinearity, and we apply the method. PMID:21929056

Mehta, Dhagash

2011-08-01

222

[Research on the method of stress assessment--from the research findings of 2010].  

Science.gov (United States)

The Japanese Society for Occupational Mental Health has conducted research on assessment of the psychological load (i.e., stress) among workers. Investigations were conducted three times, and those were contract research projects assigned by the Ministry of Health, Labour and Welfare. In this project, the author was the primary researcher. In the latest research, a survey utilizing the Live Event Method was performed extensively nationwide; the survey covered 10,494 subjects (including 1,977 females) from all types of industry and occupation. The objective of this research was to reevaluate the Psychological Load Assessment Sheet used as an evaluation basis for the "Certification of workers' compensation related to mental disorders from psychological load." Two previous research investigations, conducted in 2002 and 2006, had suggested the need for such reevaluation. The outcomes revealed that, the longer the monthly overtime working hours, the higher the stress scores (in the range of 0 to 10), and the lower the appearance rate of stress. Subjects who performed 140 hours or more of overtime work per month, which fell under the category of "Extremely Excessive Overtime Work," showed 6.3 points, which was markedly high, and ranked fourth in the survey with 63 assessment items. The category, "Extremely Excessive Overtime Work," includes two working hour ranges, 120 hours or more and 160 hours or more; those working hour ranges were defined in the revision based on the latest research. Monthly overtime work of 120 hours or more, but less than 140 hours, was ranked ninth and scored 6.3 points. Monthly overtime work of 80 hours or more, but less than 100 hours, scored 5.3 points with a frequency of 14.2%. Based on the above results, new assessment items were added to the Psychological Load Assessment Sheet. This paper addresses and studies the issues explained above. PMID:23346811

Natsume, Makoto

2012-01-01

223

Weighted Centroid Algorithm for Estimating Primary User Location: Theoretical Analysis and Distributed Implementation  

CERN Multimedia

Information about primary user (PU) location is crucial in enabling several key capabilities in dynamic spectrum access networks, including improved spatio-temporal sensing, intelligent location-aware routing, as well as aiding spectrum policy enforcement. Compared to other proposed non-interactive localization algorithms, the weighted centroid localization (WCL) scheme uses only received signal strength information, which makes it simple and robust to variations in the propagation environment. In contrast to prior work, which focused mainly on proposing algorithmic variations and verifying their performance through simulations, in this paper we present the first theoretical framework for WCL performance analysis in terms of its localization error distribution parameterized by node density, node placement, shadowing variance and correlation distance. Using this analysis, we quantify the robustness of WCL to various physical conditions and provide guidelines, such as node placement, for practical deployment of...

Wang, Jun; Han, Yuxing; ?abri?, Danijela

2010-01-01

224

K-nearest Neighbour Method of Analysing the ECG Signal (To Find out the Different Disorders Related to Heart  

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Full Text Available Heart attack is very common thing now-a-days. This results because of many disorders occurring in the heart. These disorders can be found out by analysing the ECG signal. The conventional method of analysing the ECG signal is done by the doctors who are expert in that. So far there is no systematic procedure for analysing the ECG signal. The main goal of this study is to obtain a systematic method of analysing the Electrocardiogram (ECG from the patient and display the types of disorder. The ECG from the patient is taken and by loop analysis every point in the data is checked and analysed using two new methods namely the direct comparison method and kNN method. The ECG parameters such as shape of the waveform, heart rate, time interval, amplitude (voltage etc., are taken for analysis. kNN (K-Nearest Neighbour algorithm is a search algorithm which finds the nearest distance from the training data and this method is used to compare the corresponding predefined values of different disorders of the heart with the sampled data and the inference from the comparison results are displayed. In case of multiple disorders, the KNN finds the most prominent one. Simulation is done using MATLAB.

S. Jayalalitha

2014-01-01

225

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 Global CMT catalog (http://www.globalcmt.org). RCMT computation is based on the analysis of seismograms recorded at regional distances, and modeling of intermediate period surface waves. The Catalog is regularly updated a few months behind real time, and reports are published in Phys. Earth Planet. Int. and on the worldwide web (http://www.bo.ingv.it/RCMT). However, moment tensors can also be computed on the basis of data available in quasi-real time. Such preliminary solutions are available within one or a few hours after an earthquake occurs, and published as a Quick RCMTs. The European- Mediterranean RCMT Catalog currently includes more than 850 seismic moment tensor solutions, mainly located in the most seismically active areas, such as northern Greece and the Hellenic trench. In the consideration of the size of the Catalog, we developed a web-search interface that allows to query the SQL database on geographical, time and magnitudes (mb, Ms and Mw) ranges. The results can then be formatted and 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

226

Imaging texture and porosity in mudstone and shale : findings from petrographic, secondary, and ion-milled backscatter SEM methods  

Energy Technology Data Exchange (ETDEWEB)

Sea-level cycles are important for shale gas, impacting gas generation, storage and fracture development. The objectives of petrographic studies are to answer questions of sedimentology and geology and to provide a context for interpretations of indirect measurements. This presentation discussed imaging texture and porosity in mudstone and shales. Findings from petrographic, secondary, and ion-milled backscatter scanning electron microscopy (SEM) methods were presented. Important qualitative findings that impacted porosity measurements were offered, including observed pore types; pore size range; and rock matrix, texture and diagenesis. Questions to consider in a post-Darcy universe were identified. Areas of investigation, secondary and argon-ion milled backscatter SEM methods were explored. The presentation noted that secondary electron imaging of the larger area validated that the argon-ion milled area was representative. It was concluded that the relative abundance of pore types and their sizes should be verified by observations and that variations are expected. refs., figs.

Milner, M.; Petriello, J.; McLin, R.; Gathogo, P. [TerraTek Energy Solutions, Courtenay, BC (Canada)

2010-07-01

227

Method for Estimating the Number of Radiation Sources in the Problem of the Amplitude Monopulse Direction Finding  

Science.gov (United States)

We propose an algorithm for processing the signals received by a multichannel amplitude monopulse direction-finding system, which allows one to estimate the radiation-source number in the operating region of space. The decision on the number of sources is made on the basis of the threshold method. The threshold value is determined using the criterion of minimum of the sum of the conditional error probability.

Loginov, A. A.; Morozov, O. A.; Semenova, M. Yu.; Fidelman, V. R.

2013-12-01

228

A small probabilistic universal set of starting points for finding roots of complex polynomials by Newton's method  

CERN Document Server

We specify a small set, consisting of $O(d(\\log\\log d)^2)$ points, that intersects the basins under Newton's method of \\emph{all} roots of \\emph{all} (suitably normalized) complex polynomials of fixed degrees $d$, with arbitrarily high probability. This set is an efficient and universal \\emph{probabilistic} set of starting points to find all roots of polynomials of degree $d$ using Newton's method; the best known \\emph{deterministic} set of starting points consists of $\\lceil 1.1d(\\log d)^2\\rceil$ points.

Bollobás, Béla; Schleicher, Dierk

2010-01-01

229

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

230

Collective centroid oscillations as an emittance preservation diagnostic in linear collider linacs  

International Nuclear Information System (INIS)

Transverse bunch centroid oscillations, induced at operating beam currents at which transverse wakefields are substantial, and observed at Beam Position Monitors, are sensitive to the actual magnetic focusing, energy gain, and rf phase profiles in a linac, and are insensitive to misalignments and jitter sources. In the pulse stealing set-up implemented at the SLC, they thus allow the frequent monitoring of the stability of the in-place emittance growth inhibiting or mitigating measures--primarily the energy scaled magnetic lattice and the rf phases necessary for BNS damping--independent of the actual emittance growth as driven by misalignments and jitter. The authors have developed a physically based analysis technique to meaningfully reduce the data. Oscillation beta-beating is a primary indicator of beam energy errors; shifts in the invariant amplitude reflect differential internal motion along the longitudinally extended bunch and thus are a sensitive indicator of the real rf phases in the machine; shifts in betatron phase advance contain corroborative information sensitive to both effects

1997-05-12

231

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

232

Centroid neural network with a divergence measure for GPDF data clustering.  

Science.gov (United States)

An unsupervised competitive neural network for efficient clustering of Gaussian probability density function (GPDF) data of continuous density hidden Markov models (CDHMMs) is proposed in this paper. The proposed unsupervised competitive neural network, called the divergence-based centroid neural network (DCNN), employs the divergence measure as its distance measure and utilizes the statistical characteristics of observation densities in the HMM for speech recognition problems. While the conventional clustering algorithms used for the vector quantization (VQ) codebook design utilize only the mean values of the observation densities in the HMM, the proposed DCNN utilizes both the mean and the covariance values. When compared with other conventional unsupervised neural networks, the DCNN successfully allocates more code vectors to the regions where GPDF data are densely distributed while it allocates fewer code vectors to the regions where GPDF data are sparsely distributed. When applied to Korean monophone recognition problems as a tool to reduce the size of the codebook, the DCNN reduced the number of GPDFs used for code vectors by 65.3% while preserving recognition accuracy. Experimental results with a divergence-based k-means algorithm and a divergence-based self-organizing map algorithm are also presented in this paper for a performance comparison. PMID:18541496

Park, Dong-Chul; Kwon, Oh-Hyun; Chung, Jio

2008-06-01

233

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

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Full Text Available 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 were considered in the RCO program. Three sets of optimum proposed factor values were obtained corresponding to three extraction targets respectively. The set of optimum proposed factor values for polyphenol extraction given was chosen in further experiments as following: liquid and solid ratio (v/w 8, ethanol 67.3% (v/v, initial pH 1.75, temperature 55 °C for 4 h and extraction repeated for 4 times. The Wuweizi polyphenol extract (WPE was obtained with a yield of 16.37 mg/g and composition of polyphenols 1.847 mg/g, anthocyanins 0.179 mg/g, sugar 9.573 mg/g and protein 0.327 mg/g. The WPE demonstrated high scavenging activities against DPPH radicals.

Xiong Yu

2011-09-01

234

Identification of new human cadherin genes using a combination of protein motif search and gene finding methods.  

Science.gov (United States)

We have combined protein motif search and gene finding methods to identify genes encoding proteins containing specific domains. Particularly, we have focused on finding new human genes of the cadherin superfamily proteins, which represent a major group of cell-cell adhesion receptors contributing to embryonic neuronal morphogenesis. Models for three cadherin protein motifs were generated from over 100 already annotated cadherin domains and used to search the complete translated human genome. The genomic sequence regions containing motif "hits" were analyzed by eukaryotic GeneMark.hmm to identify the exon-intron structure of new genes. Three new genes CDH-J, PCDH-J and FAT-J were found. The predicted proteins PCDH-J and FAT-J were classified into protocadherin and FAT-like subfamilies, respectively, based on the number and organization of cadherin domains and presence of subfamily-specific conserved amino acid residues. Expression of FAT-J was shown in almost all tested tissues. The exon-intron organization of CDH-J was experimentally verified by PCR with specifically designed primers and its tissue-specific expression was demonstrated. The described methodology can be applied to discover new genes encoding proteins from families with well-characterized structural and functional domains. PMID:15003449

Hoeng, Julia C; Höng, Julia C; Ivanov, Nikolai V; Hodor, Paul; Xia, Menghang; Wei, Nan; Blevins, Richard; Gerhold, David; Borodovsky, Mark; Liu, Yuan

2004-03-19

235

Neutron radiography with sub-15 {mu}m resolution through event centroiding  

Energy Technology Data Exchange (ETDEWEB)

Conversion of thermal and cold neutrons into a strong {approx}1 ns electron pulse with an absolute neutron detection efficiency as high as 50-70% makes detectors with {sup 10}B-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 {mu}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 Multiplication-Sign 2 Timepix readout with >1.2 kHz frame rates provides the unique possibility to detect neutrons with sub-15 {mu}m resolution at several MHz/cm{sup 2} counting rates. The results of high resolution neutron radiography experiments presented in this paper, demonstrate the sub-15 {mu}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 10{sup 7} n/cm{sup 2}/s taking full advantage of high beam intensity of present brightest neutron imaging facilities.

Tremsin, Anton S., E-mail: ast@ssl.berkeley.edu [Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA 94720 (United States); McPhate, Jason B.; Vallerga, John V.; Siegmund, Oswald H.W. [Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA 94720 (United States); Bruce Feller, W. [NOVA Scientific, Inc. 10 Picker Road, Sturbridge, MA 01566 (United States); Lehmann, Eberhard; Kaestner, Anders; Boillat, Pierre; Panzner, Tobias; Filges, Uwe [Spallation Neutron Source Division, Paul Scherrer Institute, CH-5232 Villigen (Switzerland)

2012-10-01

236

Quantum size correction to the work function and the centroid of excess charge in positively ionized simple metal clusters  

Directory of Open Access Journals (Sweden)

Full Text Available  In this work, we have shown the important role of the finite-size correction to the work function in predicting the correct position of the centroid of excess charge in positively charged simple metal clusters with different values . For this purpose, firstly we have calculated the self-consistent Kohn-Sham energies of neutral and singly-ionized clusters with sizes in the framework of local spin-density approximation and stabilized jellium model (SJM as well as simple jellium model (JM with rigid jellium. Secondly, we have fitted our results to the asymptotic ionization formulas both with and without the size correction to the work function. The results of fittings show that the formula containing the size correction predict a correct position of the centroid inside the jellium while the other predicts a false position, outside the jellium sphere.

M. Payami

2003-12-01

237

4fn-15d centroid shift in lanthanides and relation with anion polarizability, covalency, and cation electronegativity  

International Nuclear Information System (INIS)

Data collected on the centroid shift of the 5d-configuration of Ce3+ in oxide and fluoride compounds were recently analyzed with a model involving the correlated motion between 5d-electron and ligand electrons. The correlation effects are proportional to the polarizability of the anion ligands and it leads, like covalency, to lowering of the 5d-orbital energies. By means of ab initio Hartree-Fock-LCAO calculations including configuration interaction the contribution from covalency and correlated motion to the centroid shift are determined separately for Ce3+ in various compounds. It will be shown that in fluoride compounds, covalency provides an insignificant contribution. In oxides, polarizability appears to be of comparable importance as covalency

2002-07-13

238

Matching contours in images through the use of curvature, distance to centroid and global optimization with order-preserving constraint  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a new methodology to establish the best global match of objects’ contours in images. The first step is the extraction of the sets of ordered points that define the objects’ contours. Then, by using the curvature value and its distance to the corresponded centroid for each point, an affinity matrix is built. This matrix contains information of the cost for all possible matches between the two sets of ordered points. Then, to determine the desired one-to-one glob...

Oliveira, Francisco P. M.; Tavares, Joa?o Manuel R. S.

2009-01-01

239

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

International Nuclear Information System (INIS)

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 ?-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 ?-Fe, the possible transition states are studied as a function of interstitial cluster size, and the lowest energy barriers correspond to defect migration along directions. However, this paper addresses whether migrating interstitial clusters can thermally change their direction, and the activation energies and corresponding mechanisms for changing the direction of these clusters are determined

2003-04-01

240

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

 
 
 
 
241

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

242

Mixed methods evaluation of targeted case finding for cardiovascular disease prevention using a stepped wedged cluster RCT  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background A pilot project cardiovascular prevention was implemented in Sandwell (West Midlands, UK. This used electronic primary care records to identify untreated patients at high risk of cardiovascular disease then invited these high risk patients for assessment by a nurse in their own general practice. Those found to be eligible for treatment were offered treatment. During the pilot a higher proportion of high risk patients were started on treatment in the intervention practices than in control practices. Following the apparent success of the prevention project, it was intended to extend the service to all practices across the Sandwell area. However the pilot project was not a robust evaluation. There was a need for an efficient evaluation that would not disrupt the planned rollout of the project. Methods/design Project nurses will sequentially implement targeted cardiovascular case finding in a phased way across all general practices, with the sequence of general practices determined randomly. This is a stepped wedge randomised controlled trial design. The target population is patients aged 35 to 74, without diabetes or cardiovascular disease whose ten-year cardiovascular risk, (determined from data in their electronic records is ?20%. The primary outcome is the number of high risk patients started on treatment, because these data could be efficiently obtained from electronic primary care records. From this we can determine the effects of the case finding programme on the proportion of high risk patients started on treatment in practices before and after implementation of targeted case finding. Cost-effectiveness will be modelled from the predicted effects of treatments on cardiovascular events and associated health service costs. Alongside the implementation it is intended to interview clinical staff and patients who participated in the programme in order to determine acceptability to patients and clinicians. Practical considerations meant that 26 practices in Sandwell could be randomised, including about 6,250 patients at high risk of cardiovascular disease. This gives sufficient power for evaluation. Discussion It is possible to design a stepped wedge randomised controlled trial using routine data to determine the primary outcome to evaluate implementation of a cardiovascular prevention programme.

Marshall Tom

2012-10-01

243

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

244

Quantum size correction to the work function and the centroid of excess charge in positively ionized simple metal clusters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this work, we have shown the important role of the finite-size correction to the work function in predicting the correct positions of the centroid of excess charge in positively charged simple metal clusters with different $r_s$ values ($2\\le r_s\\le7$). For this purpose, firstly we have calculated the self-consistent Kohn-Sham energies of neutral and singly-ionized clusters with sizes $2\\le N\\le 100$ in the framework of local spin-density approximation and stabilized jell...

Payami, M.

2002-01-01

245

Targeted quantitative bioanalysis in plasma using liquid chromatography/high-resolution accurate mass spectrometry: an evaluation of global selectivity as a function of mass resolving power and extraction window, with comparison of centroid and profile modes.  

Science.gov (United States)

There is a growing interest in exploring the use of liquid chromatography coupled with full-scan high resolution accurate mass spectrometry (LC/HRMS) in bioanalytical laboratories as an alternative to the current practice of using LC coupled with tandem mass spectrometry (LC/MS/MS). Therefore, we have investigated the theoretical and practical aspects of LC/HRMS as it relates to the quantitation of drugs in plasma, which is the most commonly used matrix in pharmacokinetics studies. In order to assess the overall selectivity of HRMS, we evaluated the potential interferences from endogenous plasma components by analyzing acetonitrile-precipitated blank human plasma extract using an LC/HRMS system under chromatographic conditions typically used for LC/MS/MS bioanalysis with the acquisition of total ion chromatograms (TICs) using 10 k and 20 k resolving power in both profile and centroid modes. From each TIC, we generated extracted ion chromatograms (EICs) of the exact masses of the [M + H](+) ions of 153 model drugs using different mass extraction windows (MEWs) and determined the number of plasma endogenous peaks detected in each EIC. Fewer endogenous peaks are detected using higher resolving power, narrower MEW, and centroid mode. A 20 k resolving power can be considered adequate for the selective determination of drugs in plasma. To achieve desired analyte EIC selectivity and simultaneously avoid missing data points in the analyte EIC peak, the MEW used should not be too wide or too narrow and should be a small fraction of the full width at half maximum (FWHM) of the profile mass peak. It is recommended that the optimum MEW be established during method development under the specified chromatographic and sample preparation conditions. In general, the optimum MEW, typically ? ±20 ppm for 20 k resolving power, is smaller for the profile mode when compared with the centroid mode. PMID:21913265

Xia, Yuan-Qing; Lau, Jim; Olah, Timothy; Jemal, Mohammed

2011-10-15

246

Applications of the functional variable method for finding the exact solutions of nonlinear evolution equations in mathematical physics  

Science.gov (United States)

In this paper, the functional variable method is proposed to seek the exact solutions of some nonlinear evolution equations. The validity and advantages of the proposed method is illustrated by the applications to the Asymmetric Nizhnik-Novikov-Vesselov equation, the breaking soliton equation, the Nizhnik-Novikov-Vesselov equation and the Painlevé integrable Burgers equations, which play an important role in mathematical physics. It is shown that the proposed method provides a very effective and powerful tool for solving nonlinear evolution equations.

Zayed, E. M. E.; Hoda, S. A.; Arnous, Ibrahim A. H.

2013-10-01

247

For a reasoned development of experimental methods in information and communication sciences Some epistemological findings of methodological pluralism  

Directory of Open Access Journals (Sweden)

Full Text Available If multidisciplinarity is necessary, first, for studying the widest possible set of communication phenomena (organizational, in groups, interpersonal, media, computer-mediated communication... and, secondly, for grasping the complexity of the different moments of the same phenomenon of communication (production, content, reception, circulation ..., methodological pluralism is also important. However, French research in communication sciences leaves in the shade a number of phenomena and moments of communication that could be better understood thanks to the experimental method. We will underline that the epistemological issues related to rational use of the experimental method in communication sciences are not negligible: it allows the study of objects that cannot be investigated with other methods and offers the opportunity to build knowledge by the refutation of hypotheses and theoretical propositions. We will clarify some epistemological misunderstandings concerning this method. First, it is actually a method of studying complex systems and communication processes. Secondly, its use is not incompatible with constructivism.

Didier COURBET

2013-07-01

248

Tibiofemoral centroid velocity correlates more consistently with cartilage damage than does contact path length in two ovine models of stifle injury.  

Science.gov (United States)

Anterior cruciate ligament (ACL) rupture and/or meniscal injury are known risk factors for post-traumatic osteoarthritis. We tested the hypothesis that increasingly abnormal tibiofemoral centroid path lengths and velocities would correlate with the severity of cartilage damage in injured sheep. Six sheep underwent combined ACL/medial collateral ligament transection (ACL/MCLx), five complete lateral meniscectomy (Mx), and four sham arthrotomy (Sham). Weighted centroids were used to estimate in vivo tibiofemoral cartilage contact path length during stance and the velocity of relative motion. Cartilage morphology was graded at dissection. Ligament transection significantly elongated plateau centroid path lengths and velocities, whereas condyle paths and velocities were reduced. Differences between plateau and femoral velocities (relative centroid velocity) were increased up to 10-fold over baseline values in the medial compartment. Reductions in Mx lateral compartment paths were significantly different from ACL/MCLx paths, but not relative to baseline or Sham values. Importantly, only centroid velocities consistently correlated with cartilage damage in either injury model, suggesting that while path length is valuable in detecting changes in the envelope of joint motion, it may average out meaningful peaks in the rate of relative motion that more closely relate to the mechanisms that might be damaging articular cartilage in these models. PMID:23832294

Beveridge, Jillian E; Heard, Bryan J; Shrive, Nigel G; Frank, Cyril B

2013-11-01

249

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...

Moffatt Suzanne; White Martin; Mackintosh Joan; Howel Denise

2006-01-01

250

?????????????????????? 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

251

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

252

Weighted Centroid Modified Simplex and Linear Constrained Response Surface Optimization Methods for the Xbar-R Chart Variable Determination  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Problem statement: Although economic Xbar-R chart designs do guarantee the minimal operating cost, they typically have poor levels of statistical performance measures. The obvious limitation of the economic design is that the Type I error rate seems to be very high for many situations and will cause a large number of false alarms. This situation leads to an investigation of appropriate levels of control chart variables which consist of a sample ...

Pongchanun Luangpaiboon

2011-01-01

253

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.

Novaes, Douglas D..

254

Finding Common Solutions of a Variational Inequality, a General System of Variational Inequalities, and a Fixed-Point Problem via a Hybrid Extragradient Method  

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Full Text Available Abstract We propose a hybrid extragradient method for finding a common element of the solution set of a variational inequality problem, the solution set of a general system of variational inequalities, and the fixed-point set of a strictly pseudocontractive mapping in a real Hilbert space. Our hybrid method is based on the well-known extragradient method, viscosity approximation method, and Mann-type iteration method. By constrasting with other methods, our hybrid approach drops the requirement of boundedness for the domain in which various mappings are defined. Furthermore, under mild conditions imposed on the parameters we show that our algorithm generates iterates which converge strongly to a common element of these three problems.

Guu Sy-Ming

2011-01-01

255

Improvements and New Findings in Monte Carlo Method with Complex-valued Weights for Neutron Leakage-corrected Assembly Calculations  

Science.gov (United States)

The author of this paper recently proposed a Monte Carlo calculation algorithm to solve a complex transport equation with complex-valued weights. The algorithm enables one to generate neutron leakage-corrected group constants and anisotropic diffusion coefficients for a unit fuel pin cell or assembly. The group constants are subsequently used for multi-group deterministic core calculations. The technique, however, had some limitations in applying itself to general problems. Some improvements have been done in this paper. The reflective boundary condition has newly become available. It has been found that a cumbersome weight cancellation of fission sources with positive and negative weights can be omitted in general fuel assembly geometries. A homogenization method of diffusion coefficients for a fuel assembly has been proposed.

Yamamoto, Toshihiro

2014-06-01

256

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)

2001-01-01

257

Experimental test of a newly proposed empirical relationship between the centroid and width of the giant quadrupole resonance and the neutron binding energy of the nucleus  

International Nuclear Information System (INIS)

Via the inelastic scattering of 50 MeV/nucleon 14N ions, the giant quadrupole resonance in 58Ni and 64Ni has been investigated to test experimentally a newly proposed relationship between the centroid and width of the giant quadrupole resonance and the neutron binding energy of the nucleus. Our results do not confirm the proposed relationship

1990-01-01

258

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.

259

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

2014-07-01

260

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

2013-10-10

 
 
 
 
261

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

262

Evidence-informed health policy 1 – Synthesis of findings from a multi-method study of organizations that support the use of research evidence  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Organizations have been established in many countries and internationally to support the use of research evidence by producing clinical practice guidelines, undertaking health technology assessments, and/or directly supporting the use of research evidence in developing health policy on an international, national, and state or provincial level. Learning from these organizations can reduce the need to 'reinvent the wheel' and inform decisions about how best to organize support for such organizations, particularly in low- and middle-income countries (LMICs. Methods We undertook a multi-method study in three phases – a survey, interviews, and case descriptions that drew on site visits – and in each of the second and third phases we focused on a purposive sample of those involved in the previous phase. We used the seven main recommendations that emerged from the advice offered in the interviews to organize much of the synthesis of findings across phases and methods. We used a constant comparative method to identify themes from across phases and methods. Results Seven recommendations emerged for those involved in establishing or leading organizations that support the use of research evidence in developing health policy: 1 collaborate with other organizations; 2 establish strong links with policymakers and involve stakeholders in the work; 3 be independent and manage conflicts of interest among those involved in the work; 4 build capacity among those working in the organization; 5 use good methods and be transparent in the work; 6 start small, have a clear audience and scope, and address important questions; and 7 be attentive to implementation considerations, even if implementation is not a remit. Four recommendations emerged for the World Health Organization (WHO and other international organizations and networks: 1 support collaborations among organizations; 2 support local adaptation efforts; 3 mobilize support; and 4 create global public goods. Conclusion This synthesis of findings from a multi-method study, along with the more detailed findings from each of the three phases of the study (which are reported in the three following articles in the series, provide a strong basis on which researchers, policymakers, international organizations (and networks like WHO can respond to the growing chorus of voices calling for efforts to support the use of research evidence in developing health policy.

Moynihan Ray

2008-12-01

263

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

International Nuclear Information System (INIS)

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.)

2012-12-01

264

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

265

Iterative Methods for Finding Common Solution of Generalized Equilibrium Problems and Variational Inequality Problems and Fixed Point Problems of a Finite Family of Nonexpansive Mappings  

Directory of Open Access Journals (Sweden)

Full Text Available We introduce a new method for a system of generalized equilibrium problems, system of variational inequality problems, and fixed point problems by using -mapping generated by a finite family of nonexpansive mappings and real numbers. Then, we prove a strong convergence theorem of the proposed iteration under some control condition. By using our main result, we obtain strong convergence theorem for finding a common element of the set of solution of a system of generalized equilibrium problems, system of variational inequality problems, and the set of common fixed points of a finite family of strictly pseudocontractive mappings.

Kangtunyakarn Atid

2010-01-01

266

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

267

Magnetic resonance imaging of anterior cruciate ligament tears: reevaluation of quantitative parameters and imaging findings including a simplified method for measuring the anterior cruciate ligament angle.  

Science.gov (United States)

We evaluated the diagnostic utility of magnetic resonance imaging (MRI) for predicting anterior cruciate ligament (ACL) tears using both quantitative parameters and nonquantitative imaging findings. MRI examinations were retrospectively evaluated in a group of patients with arthroscopically confirmed complete ACL tear and in a control group with arthroscopically confirmed intact ACL. We evaluated multiple MRI features to compare their sensitivity and specificity for detecting ACL tears. Particular emphasis is put on the evaluation of three different quantitative parameters, including a simplified method for measuring the ACL angle. With a threshold value of 45 degrees the ACL angle reached a sensitivity and specificity of 100% for detecting ACL tears. With a threshold value of 0 degrees the Blumensaat angle had a sensitivity of 90% and a specificity of 98%. Finally, a threshold value of 115 degrees gave the posterior cruciate ligament angle a sensitivity of 70% and a specificity of 82%. Discontinuity was found to be the most useful of the ACL abnormalities. Of the secondary findings anterior tibial displacement was the best predictor of ligamentous injury. However, ACL abnormalities and secondary findings, alone or combined, failed to surpass the diagnostic value of the ACL angle for predicting ACL tears. Quantitative parameters are thus good predictors of ACL tears and may increase the overall sensitivity and specificity of MRI. The ACL angle may be confidently measured in a single MRI section and can be considered to be the most reliable quantitative parameter for detecting ACL tears. PMID:14530852

Mellado, J M; Calmet, J; Olona, M; Giné, J; Saurí, A

2004-05-01

268

Reconstruction of an object from its noisy Fourier modulus: ideal estimate of the object to be reconstructed and a method that attempts to find that estimate.  

Science.gov (United States)

In general, the problem of reconstructing an object from its Fourier modulus has no solution when the Fourier modulus is contaminated by noise. Therefore a quasi solution, which we call the ideal estimate of the object to be reconstructed, is defined here based on the concept of territories of the convergence objects of the error-reduction algorithm, and a method that attempts to find that solution is presented. Keeping in mind that the ideal estimate is one of the output-stagnation objects of the hybrid input-output algorithm, we modify the hybrid input-output algorithm so that the output-stagnation objects can be located even when the value of the feedback parameter is not infinitesimally small, and this modified algorithm is combined with the hybrid input-output algorithm itself. The results of computer simulations carried out to test the performance of the proposed method are shown. PMID:18324068

Takajo, H; Shizuma, T; Takahashi, T; Takahata, S

1999-09-10

269

An X-ray method for detecting substructure in galaxy clusters - Application to Perseus, A2256, Centaurus, Coma, and Sersic 40/6  

Science.gov (United States)

We use the moments of the X-ray surface brightness distribution to constrain the dynamical state of a galaxy cluster. Using X-ray observations from the Einstein Observatory IPC, we measure the first moment FM, the ellipsoidal orientation angle, and the axial ratio at a sequence of radii in the cluster. We argue that a significant variation in the image centroid FM as a function of radius is evidence for a nonequilibrium feature in the intracluster medium (ICM) density distribution. In simple terms, centroid shifts indicate that the center of mass of the ICM varies with radius. This variation is a tracer of continuing dynamical evolution. For each cluster, we evaluate the significance of variations in the centroid of the IPC image by computing the same statistics on an ensemble of simulated cluster images. In producing these simulated images we include X-ray point source emission, telescope vignetting, Poisson noise, and characteristics of the IPC. Application of this new method to five Abell clusters reveals that the core of each one has significant substructure. In addition, we find significant variations in the orientation angle and the axial ratio for several of the clusters.

Mohr, Joseph J.; Fabricant, Daniel G.; Geller, Margaret J.

1993-01-01

270

Determination of the centroid depths of the depth profiles of ion-implanted analytes by angle-resolved electron microbeam analysis  

International Nuclear Information System (INIS)

Angle-resolved signal ratio electron microbeam analysis (AR/SR/EMA) was applied for the determination of the centroid depth of the ion-implanted depth profile of 100 keV 1016 cm-2 P in Si. The experiment is part of an investigation on the suitability of AR/SR/EMA for application in the (non-destructive) calibration of ion-implanted reference materials. (author)

1990-07-01

271

Ce3+ 5d-centroid shift and vacuum referred 4f-electron binding energies of all lanthanide impurities in 150 different compounds  

International Nuclear Information System (INIS)

A review on the wavelengths of all five 4f–5d transitions for Ce3+ 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 Eu2+ 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 LaF3 and La2O3 will be constructed. - Highlights: ? An compilation on all five Ce3+ 4f–5d energies in 150 inorganic compounds is presented. ? The relationship between the 5d centroid shift and host cation electronegativity id demonstrated. ? The electronic structure scheme of the lanthanides in La2O3 and LaF3 is presented.

2013-03-01

272

Pseudometrically constrained centroidal voronoi tessellations: Generating uniform antipodally symmetric points on the unit sphere with a novel acceleration strategy and its applications to diffusion and three-dimensional radial MRI.  

Science.gov (United States)

PURPOSE: The purpose of this work is to investigate the hypothesis that uniform sampling measurements that are endowed with antipodal symmetry play an important role in image quality when the raw data and image data are related through the Fourier relationship. Currently, it is extremely challenging to generate large and uniform antipodally symmetric point sets suitable for three-dimensional radial MRI. A novel approach is proposed to solve this long-standing problem in a unique and optimal way. METHODS: The proposed method is based on constrained centroidal Voronoi tessellations of the upper hemisphere with a novel pseudometric. RESULTS: The time complexity of the proposed tessellations was shown to be effectively linear, i.e., on the order of the number of sampling measurements. For small sample size, the proposed method was comparable with the state-of-the-art method (a direct iterative minimization of the electrostatic potential energy of a collection of electrons antipodal-symmetrically distributed on the unit sphere) in terms of the sampling uniformity. For large sample size, in which the state-of-the-art method is infeasible, the reconstructed images from the proposed method has less streak and ringing artifacts, when compared with those of the commonly used methods. CONCLUSION: This work proposed a unique and optimal approach to solving a long-standing problem in generating uniform sampling points for three-dimensional radial MRI. Magn Reson Med, 2013. © 2013 Wiley Periodicals, Inc. PMID:23483638

Koay, Cheng Guan

2013-03-11

273

A Hierarchical Finite Element Method for Quantum Field Theory  

CERN Document Server

We study a model of scalar quantum field theory in which space-time 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. This renormalization dynamics has a fixed point at the celebrated cotangent formula of the Finite Element Method, which approximates the two dimensional Laplacian.

Kar, Arnab; Rajeev, S G

2013-01-01

274

Method for fast detecting the intersection of a plane and a cube in an octree structure to find point sets within a convex region  

Science.gov (United States)

Performing efficient view frustum culling is a fundamental problem in computer graphics. In general, an octree is used for view frustum culling. The culling checks the intersection of each octree node (cube) against the planes of the view frustum. However, this involves many calculations. We propose a method for fast detecting the intersection of a plane and a cube in an octree structure. When we check which child of the octree node intersects a plane, we compare the coordinates of the corner of the node and the plane. Using an octree, we calculate the vertices of the child node by using the vertices of the parent node. To find points within a convex region, a visibility test is performed by AND operation with the result of three or more planes. In experiments, we tested the problem of searching for the visible point with a camera. The method was two times faster than the conventional method, which detects a visible octree node by using the inner product of the plane and each corner of the node.

Fujimoto, K.,; Kimura, N.; Moriya, T.

2012-01-01

275

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)

The aim of the study was to establish the correlations between US and CT (analyzed separately and in combination) and relaparotomy findings both in relation to whole abdomen and pelvis examination and to particular anatomical localizations. A retrospective analysis of 102 ovarian cancer patients was performed in order to examine the accuracy of ultrasound examination (US) and computed tomography (CT) for the assessment of treatment results before second-look laparotomy and to evaluate the correlations between imaging and relaparotomy findings. Statistically significant correlation was found between US and CT (analyzed separately and in combination) and relaparotomy findings both in relation to whole abdomen and pelvis examination and to particular anatomical localizations. In subgroup 1 (54 patients after radical tumor excision, radical hysterectomy and partial omentectomy) CT results and combined CT/US results were statistically significantly more accurate than US results in relation to pathologic changes in the parenchymal organs and in the assessment of the presence of intraperitoneal fluid. In subgroup 2 (48 patients after debulking or exploratory surgery) CT and US/CT in combination were statistically significantly superior, as compared to US alone for examination of pelvic structures and combined CT/US - statistically superior when compared to US as far as parenchymal organs of the abdomen are concerned. In both subgroups 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)

2005-01-01

276

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 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)

2010-07-01

277

Topics in numerical relativity: Solving the initial value problem using adaptive mesh refinement, examining evolution stability using spectral methods, and finding apparent horizons using a mean curvature-level set method  

Science.gov (United States)

Various topics in numerical relativity will be discussed, including solving the initial value problem using adaptive mesh refinement, examining evolution stability using spectral methods, and finding apparent horizons using a mean curvature-level set method. We use the ADM 3+1 formalism, which separates the Einstein equations into four constraint equations and twelve evolution equations. The four constraint equations are then transformed via a York- Lichnerowicz transverse traceless decomposition. We give a brief discussionon variations of this decomposition. We discuss the implementation of a parallel multigrid solver with adaptive mesh refinement for solving the initial value constraint equations. Using our multigrid solver, we solve for a new class of initial data: distorted black holes using the puncture method. The ADM evolution equations have known instabilities. We explore the instabilities inherent in the evolution equations with an evolution code implemented using spectral methods with a Runge-Kutta integrator via the method of lines. An overview of spectral methods is given. We compare the results of evolving the full ADM evolution equations with stability predictions from integrating the constraint equations. Evolution instabilities can be contained by adding multiples of the constraints to the evolution equations. We show how to implicitly dictate the behavior of constraint violation during an evolution by manipulating additional constraint terms. After solving for initial data or during an evolution, it is often necessary to locate the position of the apparent horizon. We rewrite the apparent horizon equation as a surface evolving along its normal vector according to the speed of the apparent horizon equation. Instead of evolving a two dimensional surface and assuming a star shaped topology, we evolve a three dimensional surface via the level set method. This allows us to find multiple apparent horizons of any topology in generic spacetimes, either analytic or numerically generated.

Lowe, Lisa L.

278

Quality by Design approach in the development of a solvent-modified micellar electrokinetic chromatography method: finding the design space for the determination of amitriptyline and its impurities.  

Science.gov (United States)

A solvent-modified micellar electrokinetic chromatography method was set up for the simultaneous determination of the tricyclic antidepressant amitriptyline (AMI) and its main impurities. The method was developed following Quality by Design (QbD) principles according to ICH Guideline Q8(R2). QbD approach made it possible to find the design space (DS), where quality was assured. After a scouting phase, aimed at selecting a suitable capillary electrophoresis pseudostationary phase, risk assessment tools were employed to define the critical process parameters (CPPs) to be considered in a screening phase (applied voltage, concentration and pH of the background electrolyte, concentration of the surfactant sodium dodecyl sulphate, of the cosurfactant n-butanol and of the organic modifiers acetonitrile and urea). The effects of the seven selected CPPs on critical quality attributes (CQAs), namely resolution values between critical peak pairs and analysis time, were investigated throughout the knowledge space by means of a symmetric screening matrix. Response surface study was then carried out on four selected CPPs by applying a Doehlert Design. Monte-Carlo simulations were performed in order to estimate the probability of meeting the desired specifications on CQAs, and thus to define the DS by means of a risk of failure map. Additional points at the edges of the DS were tested in order to verify the requirements for CQAs to be fulfilled. A control strategy was implemented by defining system suitability tests. The developed method was validated following ICH Guideline Q2(R1), including robustness assessment by Plackett-Burman design, and was applied to the analysis of real samples of amitriptyline coated tablets. PMID:24176512

Furlanetto, S; Orlandini, S; Pasquini, B; Del Bubba, M; Pinzauti, S

2013-11-13

279

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

280

Computerized image-searching method for finding correct patients for misfiled chest radiographs in a PACS server by use of biological fingerprints.  

Science.gov (United States)

We have developed an automated image-searching method based on biological fingerprints for identifying correct patients in misfiled chest radiographs in a picture archiving and communication system (PACS) server. We used five biological fingerprints including distinctive anatomic structures in a misfiled chest radiograph of an unknown patient to find another image of the same patient stored with correct patient information in a PACS server. The correlation values were determined for the corresponding biological fingerprints in all images in the image server. The correlation indices as a measure of the overall similarity of the two images were determined from the summation of five correlation values and the combination of correlation values with the weighting factors. Finally, the correct patient was identified automatically by the image with the highest correlation index. By use of the summation of five correlation values as the correlation index, 78.0% (156/200) of the 200 patients for misfiled images were correctly identified in the database. When we applied the weighting factors for each biological fingerprint to determine the correlation index, the performance in identifying the correct patient was improved to 87.5% (175/200). An additional 5.0% (10/200) of images were included in the Top 10 ranking of the correlation index in the database. These cases could be identified manually by radiology personnel. We conclude that the automated image-searching method based on biological fingerprints with weighting factors would be useful for identification of the correct patient in the case of misfiled chest radiographs in a PACS server. PMID:23771325

Toge, Risa; Morishita, Junji; Sasaki, Yasuo; Doi, Kunio

2013-07-01

 
 
 
 
281

Accuracy of unfolded map method for determining the left ventricular border. Evaluation of the cut-off value from autopsy finding  

Energy Technology Data Exchange (ETDEWEB)

To improve the quantification of the left ventricular surface area (LVSA) by unfolded map method, we evaluated the cut-off value for determining the left ventricular border. The LVSA measured by unfolded map was compared with those measured using myocardial phantom and autopsy findings. The relative error (RE) was calculated as difference between LVSA in phantom and area of unfolded map. In phantom study, the cut-off value was calculated as 73.3{+-}0.5% when the RE was zero. In autopsy study, the cut-off value was 74.0{+-}7.2%. The area of unfolded map had good correlation with LVSA at autopsy when the cut-off value was 74% (r=0.83, p<0.003). The diameter of left ventricle at autopsy was compared with that of beating heart obtained by two-dimensional echocardiography, because the area of unfolded map was greater than LVSA at autopsy. The ratio of LVSA at autopsy to beating heart was calculated as 1.37. The suitable cut-off value was evaluated as 55.6% when the unfolded map area obtained by autopsy was increased 1.37 magnifications. There was a good correlation between LVSA of unfolded map (cut-off=56%) and the LVSA at autopsy (r=0.90, p<0.001). These results suggest that the cut-off value for determining the left ventricular border in vivo is 56%. (author)

Sugibayashi, Keiichi; Abe, Yoshiteru; Suga, Yutaka [Kansai Medical Univ., Moriguchi, Osaka (Japan)] [and others

1996-09-01

282

Experimental Test of Data Analysis Methods from Staggered Pair X-ray Beam Position Monitors at Bending Magnet Beamlines  

International Nuclear Information System (INIS)

Different methods have been proposed to calculate the vertical position of the photon beam centroid from the four blade currents of staggered pair X-ray beam position monitors (XBPMs) at bending magnet beamlines since they emerged about 15 years ago. The original difference-over-sum method introduced by Peatman and Holldack is still widely used, even though it has been proven to be rather inaccurate at large beam displacements. By systematically generating bumps in the electron orbit of the ANKA storage ring and comparing synchronized data from electron BPMs and XBPM blade currents, we have been able to show that the log-ratio method by S. F. Lin, B.G. Sun et al. is superior (meaning the characteristic being closer to linear) to the ratio method, which in turn is superior to the difference over sum method. These findings are supported by simulations of the XBPM response to changes of the beam centroid. The heuristic basis for each of the methods is investigated. The implications on using XBPM readings for orbit correction are discussed

2013-03-22

283

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2010-01-01

284

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 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

1982-06-21

285

H.U.B city steps: methods and early findings from a community-based participatory research trial to reduce blood pressure among african americans  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Community-based participatory research (CBPR has been recognized as an important approach to develop and execute health interventions among marginalized populations, and a key strategy to translate research into practice to help reduce health disparities. Despite growing interest in the CBPR approach, CBPR initiatives rarely use experimental or other rigorous research designs to evaluate health outcomes. This behavioral study describes the conceptual frameworks, methods, and early findings related to the reach, adoption, implementation, and effectiveness on primary blood pressure outcomes. Methods The CBPR, social support, and motivational interviewing frameworks are applied to test treatment effects of a two-phased CBPR walking intervention, including a 6-month active intervention quasi experimental phase and 12-month maintenance randomized controlled trial phase to test dose effects of motivational interviewing. A community advisory board helped develop and execute the culturally-appropriate intervention components which included social support walking groups led by peer coaches, pedometer diary self-monitoring, monthly diet and physical activity education sessions, and individualized motivational interviewing sessions. Although the study is on-going, three month data is available and reported. Analyses include descriptive statistics and paired t tests. Results Of 269 enrolled participants, most were African American (94% females (85% with a mean age of 43.8 (SD = 12.1 years. Across the 3 months, 90% of all possible pedometer diaries were submitted. Attendance at the monthly education sessions was approximately 33%. At the 3-month follow-up 227 (84% participants were retained. From baseline to 3-months, systolic BP [126.0 (SD = 19.1 to 120.3 (SD = 17.9 mmHg; p Conclusions This CBPR study highlights implementation factors and signifies the community's active participation in the development and execution of this study. Reach and representativeness of enrolled participants are discussed. Adherence to pedometer diary self-monitoring was better than education session participation. Significant decreases in the primary blood pressure outcomes demonstrate early effectiveness. Importantly, future analyses will evaluate long-term effectiveness of this CBPR behavioral intervention on health outcomes, and help inform the translational capabilities of CBPR efforts.

Molaison Elaine

2011-06-01

286

Accelerated steered response power method for sound source localization via clustering search  

Science.gov (United States)

The steered response power-phase transform (SRP-PHAT) sound source localization algorithm is robust in a real environment. However, the large computation complexity limits the practical application of SRP-PHAT. For a microphone array, each location corresponds to a set of time differences of arrival (TDOAs), and this paper collects them into a TDOA vector. Since the TDOA vectors in the adjacent regions are similar, we present a fast algorithm based on clustering search to reduce the computation complexity of SRP-PHAT. In the training stage, the K-means or Iterative Self-Organizing Data Analysis Technique (ISODATA) clustering algorithm is used to find the centroid in each cluster with similar TDOA vectors. In the procedure of sound localization, the optimal cluster is found by comparing the steered response powers (SRPs) of all centroids. The SRPs of all candidate locations in the optimal cluster are compared to localize the sound source. Experiments both in simulation environments and real environments have been performed to compare the localization accuracy and computational load of the proposed method with those of the conventional SRP-PHAT algorithm. The results show that the proposed method is able to reduce the computational load drastically and maintains almost the same localization accuracy and robustness as those of the conventional SRP-PHAT algorithm. The difference in localization performance brought by different clustering algorithms used in the training stage is trivial.

Zhao, XiaoYan; Tang, Jie; Zhou, Lin; Wu, ZhenYang

2013-07-01

287

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

288

[Usefulness of comparing of magnetic resonance imaging (MRI) findings prior to repeat biopsy and negative initial biopsy as a decision-making method for repeat prostate biopsy].  

Science.gov (United States)

We retrospectively reviewed the data from a cohort of 44 patients with one initial negative transrectal ultrasound-guided prostate biopsy who underwent a repeat biopsy from 2006 to 2013. At each biopsy session, we checked patient age, serum prostate specific antigen (PSA), prostate volume, PSA density, PSA velocity, months from the initial biopsy session, multiparametric magnetic resonance imaging (MRI) findings (T2-weighted, dynamic contrast-enhanced and diffusion-weighted, 1.5 Tesla pelvic-phased array) prior to repeat biopsy and initial negative biopsy. Mean age was 68.2±8.82 years. PSA was 11.5±7.65 ng/ml before repeat biopsy. Prostate cancer was detected in 15 (34.0%) patients at repeat biopsy. In univariate and multivariate analysis, positive MRI findings before repeat biopsy were significant independent predictors of a positive repeat biopsy. At per patient analysis, the sensitivity, specificity, positive and negative predictive values were 66.6, 68.9, 71.4 and 80.0% for MRI before repeat biopsy. No suspicious lesion on MRI before repeat biopsy was relevant to negative biopsy. According to the comparison of MRI findings prior to repeat biopsy and negative initial biopsy, suspicious MRI findings at the peripheral zone before repeat biopsy and initial negative biopsy were relevant to a high cancer detection rate (83.3%) at repeat prostate biopsy. These results suggested that the absence of a suspicious lesion on MRI before repeat biopsy could guide the avoidance of repeat biopsy and suspicious MRI findings at the peripheral zone before repeat biopsy and initial negative biopsy could guide repeat biopsy. PMID:24882227

Sawazaki, Harutake; Sengiku, Atsushi; Imamura, Masaaki; Takahashi, Takeshi; Ogura, Keiji; Kobayashi, Hisato

2014-04-01

289

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.)

1980-01-01

290

A generalized F-expansion method to find abundant families of Jacobi Elliptic Function solutions of the (2 + 1)-dimensional Nizhnik-Novikov-Veselov equation  

International Nuclear Information System (INIS)

In the present paper, a generalized F-expansion method is proposed by further studying the famous extended F-expansion method and using a generalized transformation to seek more types of solutions of nonlinear partial differential equations. With the aid of symbolic computation, we choose (2 + 1)-dimensional Nizhnik-Novikov-Veselov equations to illustrate the validity and advantages of the method. As a result, abundant new exact solutions are obtained including Jacobi Elliptic Function solutions, soliton-like solutions, trigonometric function solution etc. The method can be also applied to other nonlinear partial differential equations

2006-02-01

291

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  

Directory of Open Access Journals (Sweden)

Full Text Available 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

2010-01-01

292

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

293

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 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

2007-02-01

294

Find a modern and quick method to determine the U value and the thermal characteristics of a building envelope using an IR camera  

Digital Repository Infrastructure Vision for European Research (DRIVER)

  The overall heat transfer coefficient of a building wall, the U value, is an interesting parameter to deduce the heat loss rate through the wall. The current method to determine this U value is well known, but is requires a lot of time to be performed. In this work a new idea of methodology is presented to get an accurate idea of the U value in a really smaller time, using an IR camera. IR thermography is a non destructive method that is mainly used today to carry out qualitative observati...

Thouvenel, Julie

2012-01-01

295

Method and Apparatus for Segmenting a Speech Waveform.  

Science.gov (United States)

A system that synchronously segments a speech waveform using pitch period and a center of the pitch waveform. The pitch waveform center is determined by finding a local minimum of a centroid histogram waveform of the low-pass filtered speech waveform for ...

G. S. Kang L. J. Fransen

1995-01-01

296

Splitting Methods for Convex Clustering  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Clustering is a fundamental problem in many scientific applications. Standard methods such as $k$-means, Gaussian mixture models, and hierarchical clustering, however, are beset by local minima, which are sometimes drastically suboptimal. Recently introduced convex relaxations of $k$-means and hierarchical clustering shrink cluster centroids toward one another and ensure a unique global minimizer. In this work we present two splitting methods for solving the convex clusterin...

Chi, Eric C.; Lange, Kenneth

2013-01-01

297

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  

Directory of Open Access Journals (Sweden)

Full Text Available 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 identificação 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.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

2011-01-01

298

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

299

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

300

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

 
 
 
 
301

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

2008-04-01

302

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

303

???: FindPept  

Full Text Available 09000 09910 ????????????????? | ????????? FindPept WWW ExPASy|http://e xpasy.org/tools/findpept.html ?? ??? MS?????????????????????? ??????????? ???????????? FindPept, a tool to identif

304

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

305

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

306

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.

307

Glossopharyngeal neuralgia: MR findings  

International Nuclear Information System (INIS)

Objective: To investigate the possibility of MRI on visualizing the relationship between glossopharyngeal nerve and surrounding vessels, and to evaluate the significance of MRI in the diagnosis and treatment of glossopharyngeal neuralgia. Methods: MRI findings were analyzed retrospectively in 12 patients with glossopharyngeal neuralgia, and were compared with surgical findings and effect of pain relief. Results: The artery compression or contact of the glossopharyngeal entry zone, as revealed during operation in 10 patients with glossopharyngeal neuralgia, was visualized on MRI in 9 and not seen in 1. The venous compression of the glossopharyngeal entry zone was not identified on MRI in 1. The conglutinative arachnoids of the glossopharyngeal entry, zone was not visualized on MRI in 1. MRI demonstrated the affected glossopharyngeal nerve root entry zone was compressed or contacted by the posterior inferior cerebellar artery. (PICA) in 8 patients and by the vertebral artery in 1 patient. One patient's offending vessel was confirmed to be the anterior inferior cerebellar artery (AICA) by the operation, and the surgical findings were corresponded with MRI in others. Vascular compression or' contact of the affected glossopharyngeal nerve was not visualized on MRI in 3 patients, and operation confirmed that the glossopharyngeal nerve root entry zone was compressed by unknown artery in 1, by small vein in 1, and by conglutinative arachnoids in 1, respectively. Eight patients presented with symptoms of the ipsilateral trigeminal neuralgia concurrently. The compression of the affected trigeminal nerve root by superior cerebellar artery (SCA) was visualized on MRI in 6 patients, and operation did not reveal the source of artery compression in 1 and corresponded with MRI findings in other 5 cases. Vascular compression of affected trigeminal nerve was not visualized on MRI in 2 patients, and intraoperative inspection revealed that trigeminal nerve root was compressed by draining vein of brainstem in 1 and not compressed by any vessels in 1. All patient's neuralgia resolved alter microvascular decompression of glossopharyngeal nerve and trigeminal nerve. Conclusion: It is possible to visualize the glossopharyngeal and surrounding arteries on MRI, and it is of great significance in the diagnosis and treatment of this kind of glossopharyngeal neuralgia. (authors)

2007-03-01

308

MRI finding of hemangioblastomas  

International Nuclear Information System (INIS)

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

1994-05-01

309

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

310

Finding beam focus errors automatically  

International Nuclear Information System (INIS)

An automated method for finding beam focus errors using an optimization program called COMFORT-PLUS. The steps involved in finding the correction factors using COMFORT-PLUS has been used to find the beam focus errors for two damping rings at the SLAC Linear Collider. The program is to be used as an off-line program to analyze actual measured data for any SLC system. A limitation on the application of this procedure is found to be that it depends on the magnitude of the machine errors. Another is that the program is not totally automated since the user must decide a priori where to look for errors

1987-03-16

311

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.

312

Analysis of apparent integrated backscatter coefficient and backscattered spectral centroid shift in Calcaneus in vivo for the ultrasonic evaluation of osteoporosis.  

Science.gov (United States)

The purposes of our study were to evaluate the correlation among apparent integrated backscatter coefficient (AIB), spectral centroid shift (SCS) of ultrasonic backscatter signals and bone mineral density (BMD) and to examine the effectiveness of ultrasound variables as predictors of osteoporosis. A total of 1011 persons aged 21-80 y old were included. All study participants underwent BMD measurements of the lumbar spine (LSBMD) and the femoral neck (FNBMD). The participants also underwent calcaneal measurements to determine AIB and SCS with central frequencies of 3.5 (one transducer) and 5.0 MHz (the other transducer). AIB decreased with age and was positively correlated with BMD, while SCS increased with age and was negatively correlated with BMD. The correlation coefficient of SCS with LSBMD and FNBMD at 3.5 MHz was -0.72 and -0.70, respectively. The correlation coefficient at 5.0 MHz was -0.75 and -0.74, respectively. The correlation coefficient of AIB with LSBMD and FNBMD at 3.5 MHz was 0.65 and 0.63. The correlation coefficient at 5.0 MHz was 0.59 and 0.55, respectively. The correlation between SCS and BMD was significantly better than the correlation between AIB and BMD. Using receiver operating characteristic analysis, a significant difference was found between the areas under the curve for SCS and AIB at 3.5 MHz (0.781 vs. 0.715, respectively, p < 0.05), as well as at 5.0 MHz (0.782 vs. 0.709, respectively, p < 0.05). The optimum T-score threshold for SCS was -1.3 for both transducers. The sensitivity and specificity of SCS at 3.5 MHz and 5.0 MHz for the optimum threshold were 64%, 85%, 63% and 86%, respectively. In conclusion, the correlations among the ultrasound parameters and BMDs are strong. SCS performs better than AIB in differentiating patients with osteoporosis. Ultrasound variables may be taken into consideration as predictors of osteoporosis in the future considering its portability. PMID:24642217

Jiang, Yun-qi; Liu, Cheng-cheng; Li, Ruo-yu; Wang, Wen-ping; Ding, Hong; Qi, Qing; Ta, Dean; Dong, Jian; Wang, Wei-qi

2014-06-01

313

Sonographic Findings of Human Fascioliasis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background/Objective: Ultrasonography is an imaging modality which is easy to use and less expensive than other imaging methods. It is becoming more widely available in regions of the world where Fasciola hepatica infestation is prevalent. In this report, we described the sonographic findings of hepatic lesions in patients with fascioliasis. Patients and Methods: In this cross-sectional study, 248 patients with confirmed hepatic fascioliasis from Guilan province who were referred by internist...

2006-01-01

314

Improve the Robustness of Range-Free Localization Methods on Wireless Sensor Networks using Recursive Position Estimation Algorithms  

Directory of Open Access Journals (Sweden)

Full Text Available The position of a sensor node at wireless sensor networks determines the received data sensing accuracy. By the knowledge of sensor positioning, the location of target sensed can be estimated. Localization techniques used to find out the position of sensor node by considering the distance of this sensor from the vicinity reference nodes. Centroid Algorithm is a robust, simple and low cost localization technique without dependence on hardware requirement. We propose Recursive Position Estimation Algorithm to obtain the more accurate node positioning on range-free localization technique. The simulation result shows that this algorithm has the ability on increasing position accuracy up to 50%. The trade off factor shows the smaller the number of reference nodes the higher the computational time required. The new method on the availability on sensor power controlled is proposed to optimize the estimated position.

Gamantyo Hendrantoro

2011-12-01

315

Radiological findings in pulmonary sequestration  

International Nuclear Information System (INIS)

Pulmonary sequestration is a rare congenital disorder, the clinical diagnosis of which is difficult and requires the aid of imaging methods. We present our experience in 5 patients with pulmonary sequestration (4 intralobar and 1 extralobar) confirmed by pathology. We assess the radiological findings using the different imaging techniques. (Author) 16 refs

1994-01-01

316

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

317

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

318

Radiologic findings of anthracofibrosis  

International Nuclear Information System (INIS)

To evaluate the CT findings of bronchial anthracofibrosis. Fourteen patients with bronchoscopically confirmed anthracofibrosis were involved in this study. CT findings (n=3D12) were retrospectively analysed; the pattern, distri-bution and extent of bronchial and parenchymal abnormalities and additional findings such as mediastinal lymphadenopathy and pleural effusion were assessed. Age, sex, and occupational and disease history were history were also reviewed. Patients were aged between 63 and 95 (mean, 71.3) years, and ten were female. Only one patient had an occupational history, but four had a history of pulmonary tuberculosis. Frequent radiologic findings were bronchial wall thickening(n=3D6), atelectasis(n=3D8), mediastinal lymphad-enopathy(n=3D7) and mass(n=3D4). Other accompanying findings were bronchial wall calcification(n=3D3), consolidation(n=3D2) and pleural effusion(n=3D2). Right upper (n=3D7) and right middle lobe(n=3D7) were the most commonly involved sites, and multifocal involvement (n=3D7) was frequent. Bronchial wall thickening, atelectasis and mediastinal lymphadenopathy were characteristic CT findings of anthracofibrosis. When such findings are noted in older or aged female patients, anthracofibrosis should be included in the differential diagnosis

1998-09-01

319

Finding an NQT position  

...Finding an NQT position Institute of Physics This site uses cookies. By continuing to use this site you agree to our use of ... IOP Institute of Physics For physics bull; For physicists bull; For all Home News About us Contact us Calendar MyIOP Search ...Careers Policy Resources You are here Education I am new to teaching physics Student teachers Finding an NQT position I ...am new to teaching physics Student teachers Student teacher affiliation Finding an NQT position When to look Where to look Extra Responsibilities Interviews Physicists ...

320

Fact Finding Nuclear Energy; Fact Finding Kernenergie  

Energy Technology Data Exchange (ETDEWEB)

Facts and figures on nuclear energy are presented to enable a discussion on the role of nuclear power in the transition to a sustainable energy supply for the Netherlands. The following issues are presented: Nuclear technology, safety and security (including non-proliferation and protection against terrorism); Environmental aspects (including greenhouse gas emissions of the nuclear energy lifecycle); Nuclear power and the power market (including impact of nuclear power on electricity market prices); Economic aspects (including costs of nuclear power and external costs and benefits); Policy issues (including sustainable development); Social acceptance of nuclear energy; Knowledge infrastructure for nuclear energy in the Netherlands; and Nuclear power in long term energy scenarios for the Netherlands and Europe. Using two long-term energy scenarios the report also presents a social impact analysis of an increasing share of nuclear power in the Dutch electricity supply. [Dutch] In dit onderzoek zijn feiten en gegevens over kernenergie verzameld op basis van bestaande inzichten en een veelheid aan literatuur (fact finding). Voor technologische expertise heeft ECN zich laten bijstaan door de Nucleair Research and consultancy Group (NRG). Op basis van de fact-finding studie bereidt de SER een advies voor over de rol van kernenergie in de toekomstige nationale elektriciteitsproductie. In de eerste acht hoofdstukken worden feiten en gegevens gepresenteerd over verschillende onderwerpen die bij kernenergie van belang zijn. In Hoofdstuk 2 wordt de kernenergietechnologie beschreven, inclusiefde veiligheid van kernenergie besproken, omdat die nauw met de technologie samenhangt. Hierbij gaat het om de technische veiligheid van de installaties, maar ook om beveiliging tegen misbruik van technologie en nucleair materiaal, waaronder beveiliging tegen terrorisme. De milieuaspecten door radioactiviteit en door emissies van kooldioxide die met het gebruik van kernenergie samenhangen worden in Hoofdstuk 3 besproken. In hoofdstuk 4 wordt eerst uitgelegd hoe de elektriciteitsprijs in een geliberaliseerde elektriciteitsmarkt tot stand komt en wordt nagegaan of uitbreiding van het productievermogen met kernenergie daar invloed op zou kunnen hebben. Ook wordt de concurrentie met andere elektriciteitsproductietechnologieen besproken. Verder komen mededingingsaspecten aan de orde en inpassing in het Nederlandse elektriciteitssysteem. In Hoofdstuk 5 wordt een overzicht gegeven van kosteninformatie over kernenergie. Daarnaast wordt de economische rentabiliteit van kernenergie besproken, evenals externe kosten en baten. In Hoofdstuk 6 wordt eerst ingegaan op de vraag aan welke voorwaarden kernenergie moet voldoen om een rol te kunnen spelen in (een overgangsfase naar) een duurzame energievoorziening. Hierna wordt de rol van de overheid besproken bij het maken van keuzes over voorwaarden van kernenergie en het vertalen daarvan in wet- en regelgeving. Ook wordt een overzicht gegeven van het kernenergiebeleid in een aantal andere Europese landen. Hoofdstuk 7 gaat over maatschappelijke acceptatie en bespreekt hoe risicoperceptie van kernenergie wordt onderzocht. Daarnaast worden resultaten gepresenteerd van onderzoek naar opvattingen en meningen van de bevolking over kernenergie. In Hoofdstuk 8 wordt de Nederlandse kennisinfrastructuur op het gebied van kernenergie beschreven, alsmede de nucleaire kennis bij de overheid en de toekomstige kennisinfrastructuur. Hoofdstuk 9 geeft een overzicht van verschillende Nederlandse en Europese lange termijn toekomstscenario's voor de elektriciteitsvoorziening en de rol die kernenergie daarin kan spelen. Om een beeld te kunnen geven van mogelijke maatschappelijke gevolgen van uitbreiding van kernenergie in Nederland, is een maatschappelijke impact analyse uitgevoerd. Een dergelijke analyse beschrijft op systematische wijze de mogelijke economische en sociale effecten van een nieuwe kerncentrale en de effecten op het milieu. De resultaten van deze analyse worden beschreven in Hoofdstuk 10. Bij de analyse is gebru

Scheepers, M.J.J.; Seebregts, A.J.; Lako, P. [ECN-Beleidsstudies, Petten (Netherlands); Blom, F.J.; Van Gemert, F. [Sociaal-Economische Raad SER, Den Haag (Netherlands)

2007-09-15

 
 
 
 
321

Soft tissue masses: Ultrasonographic findings  

International Nuclear Information System (INIS)

Ultrasonography is a readily available, noninvasive and relatively inexpensive method in detecting a soft tissue mass and determining its size and consistency. Although it does not provide the anatomic details that CT or MR offer in the evaluation of soft tissue masses, ultrasound, nevertheless, plays an important role in the diagnostic workup of suspected soft tissue masses and remains a preferred diagnostic modality especially in evaluating an extremity mass without bony abnormality on plain radiographs. Therefore, we describe the ultrasonographic findings of soft tissue masses and correlate them with pathologic findings.

2001-12-01

322

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

323

Find a Dentist  

Science.gov (United States)

... information you need from the Academy of General Dentistry Tuesday, May 27, 2014 About | Contact Find an ... more. Disclaimer of Liabilities The Academy of General Dentistry's (AGD) Web site provides a listing of members ...

324

Find a Free Clinic  

Science.gov (United States)

... Membership Benefits Members Only Area Login Find a Free or Charitable Clinic Search for clinics near ... Within ... 7 8 9 … next › last » National Association of Free & Charitable Clinics Address 1800 Diagonal Road, Suite 600 ...

325

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%)

1981-12-01

326

Finding a PTSD Therapist  

Science.gov (United States)

... National Center for PTSD » Public » Finding a Therapist PTSD: National Center for PTSD PTSD PTSD Home For the Public Public Section ... Health Connect with us Share this page Search PTSD Site Choose Section Enter Term and Search Advanced ...

327

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,

328

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.

2010-01-01

329

Radiologic findings of emphysematous pyelonephritis  

Energy Technology Data Exchange (ETDEWEB)

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.

Jung, Jung Im; Byun, Jae Young; Kim, Taek Geun; Ro, Hee Jeoug; Shinn, Kyung Sub [Catholic University Medical College, Seoul (Korea, Republic of)

1995-01-15

330

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

331

Videonystagmographic Finding in Meniere's Patients  

Directory of Open Access Journals (Sweden)

Full Text Available Back ground and Objective: Vertigo is the most common complaints of patients who refer to physician and menier's disease is one of the most common causes of it. Diagnose of menier's disease depend on clinical finding. Vestibular tests are affect the treatment method and prognosis of disease, to differentiate it from other causes of vertigo as well. In this study we performed evaluation and analysis of videonystagmoghrapy (VNG finding in menier's disease.Subjects and Methods: Total 61 patients with menier’s disease referred to ENT outpatient department of Imam Khomeini and Apadana Hospitals were evaluated with VNG and Sacade, Smooth pursuit, Optokinetic, Positional and caloric tests. SPSS 16 software for data analysis was used.Results: Directional preponderance was found in 11.44%, unilateral weakness in 39.33% and Latency of sacad in 42.6% with abnormal results.Conclusion: There was no significant correlation between severity of vertigo, severity of hearing loss, duration of Disease and videonysta- gmography finding. Unilateral weakness was most important finding in this study. Sci Med J 2011; 10(3:289-293

Saki Nasser

2011-07-01

332

Fibrosing mediastinitis - radiological findings  

International Nuclear Information System (INIS)

The authors report a diffuse pattern case of idiopathic fibrosing mediastinitis in a 25-year-old woman with headache, face and chest swelling, and pain in the right upper extremity. The chest radiographic finding was a mediastinal mass and a diffuse soft process in the computed tomography. The diagnosis was made after exploratory surgery. The patient has been under steroid therapy for two years without detectable changes in radiographic findings. The authors also report the differential diagnosis and the radiological imaging role in the diagnosis and follow-up of patients with fibrosing mediastinitis. (author)

1996-01-01

333

Antrochoanal polyp: CT findings  

International Nuclear Information System (INIS)

An antrochoanal polyp is a solitary polypoid mass that arises from the maxillary sinus, and protrudes through the natural ostium into the middle meatus, and reaches the choana. The polyp does not differ histologically from an ordinary nasal polyp, which is composed of edematous, hyperplastic submucosal connective tissue stroma, and is relatively hypocellular. In this sequence of events, its computed tomographic(CT) findings are characteristic. We retrospectively analyzed CT studies of nine cases, all of which showed similar CT findings: a solitary, homogeneous, hypodense mass without bony destruction that extends from the maxillary sinus through the widened ostium into choana

1992-07-01

334

Intrathoracic gossypiboma: imaging findings  

International Nuclear Information System (INIS)

The authors report three cases of intrathoracic foreign body that is defined as a cotton matrix mass, mostly retained surgical sponge, a rare complication of a thoracic surgery. The patients were evaluated by chest radiography and computed tomography with the imaging findings confirmed after thoracotomy and anatomopathological study. The mainly imaging findings consisted of intrathoracic masses in patients with previous thoracic surgery that return to hospital with lower respiratory tract symptoms in different period after surgery procedure. The three cases were related with a brief review of the literature. (author)

2006-10-01

335

Union-Find Volume Segmentation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present an efficient method to segment large 3d images that takes the whole 3-dimensional structure into account. We use a Union-Find data structure to record and maintain the necessary informations during the segmentation process. This structure leads to a volume labelling and facilitates interactive process by linking directly voxels to the volume they belong to. Moreover the global integration of all the data enhances the accuracy of statistical merging criteria.

Fiorio, Christophe; Gustedt, Jens; Lange, Thomas

2000-01-01

336

Primary cerebral lymphoma: radiological findings  

International Nuclear Information System (INIS)

We present four cases of primary cerebral lymphoma in non-immunodepressed adult patients. All cases were dsemonstrated with pathological study. CAT study showed solitary or multiple isodense lesions, which incorporated avidly and homoneneously the contrast. Arteriography performed in three patients and magnetic resonance, performed in one did not help for diagnosis. We also review the radiological findings obtained with different imaging methods, and suggest the criteria which could be useful for early diagnosis (Author)

1990-01-01

337

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)

1986-05-15

338

Neuroblastoma: computed tomographic findings  

Energy Technology Data Exchange (ETDEWEB)

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.

Yoon, Choon Sik; Ahn, Chang Su; Kim, Myung Jun; Oh, Ki Keun [College of Medicine, Yonsei University, Seoul (Korea, Republic of)

1994-01-15

339

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

1994-01-01

340

Implementing Institutional Research Findings.  

Science.gov (United States)

Although many agree that institutional research in higher education has come of age and is accepted as a part of institutional management, great variations exist in the extent to which institutional research findings are synthesized and utilized in management decision-making. A number of reasons can be identified as accounting for this phenomenon,…

Blai, Boris, Jr.

 
 
 
 
341

Find A Grave  

Science.gov (United States)

Looking for genealogical information about long deceased relatives can often prove to be troubling and at times expensive, to say nothing of locating where they might be buried in order to pay your respects. Find a Grave is an excellent way to locate the burial places of family and friends, and it is completely free of charge. From their site, visitors can search for the graves of relatives and ancestors by typing in their surname, which will allow the search engine to query over 3.8 million burial records. Additionally, visitors can search through different cemeteries and make their own contributions to the Web site about family members and other loved ones. Along with making contributions to the site's database (a prime reason that the site has so many burial records), visitors make join discussion forums or share their success stories about locating burial sites and so on. For visitors looking to find the burial place of a famous individual, Find A Grave has another massive database, searchable by name, location, and date, with many of the entries containing a photograph of the famous individual and some brief biographical information. While the subject of death is a rather emotive and personal one, Find A Grave has done a fine job of providing an important information source for many individuals, attested to by the many success stories posted on the site.

2000-01-01

342

MR findings of craniopharyngioma  

International Nuclear Information System (INIS)

Craniopharyngioma is a benign, slow-growing tumor that constitues 3-9% of all intracranial tumors, and arises from epithelial remnants of the Rathke's pouch. We analyzed MR (2.0T) findings of ten cases with surgically proved craniopharyngioma retrospectively. CT was available in five cases, and Gd-DTPA was used in six cases. Characteristic findings of craniopharyngioma in MRI included multilocularity and variable signal intensities within each loculus that were more prominent in T1WI. Detection rate of calcification in MR was 60%. Six cases with Gd-DTPA enhancement revealed irregular or rim-like enhancement. MRI provides useful information regarding the location, extent and biochemical characteristics of the oraniopharyngioma as well as its relationship to the neighboring structures which will be valuable in planning surgical resection

1992-11-01

343

Radiological findings of clonorchiasis  

International Nuclear Information System (INIS)

Radiological findings of clonorchiasis, based on plain film, upper gastrointestinal series, hypotonicduodenography and percutaneous transhepatic cholangiography, were presented in 11 cases of clonorchiasis pathologically confirmed at Seoul National University Hospital during the period from July 1974 to May 1979. No specific features were noted in plain film of simple abdomen, upper gastrointestinal series and hypotonic duodenography, as expected. Percutaneous transhepatic cholangiographic findings are as follows: 1. dilatation of intrahepatic bile ducts, more pronounced in the periphery: 10/11 cases. 2. irregular contour of intrahepatic duct: 9/11 cases. 3. Filling defects: 9/11 cases. 4. hazy appearance of intrahepatic duct: 8/11 cases. 5. irregular contour of common bile duct: 7/11 cases. 6. dilatation of common bile duct: 3/11 cases. 7. enlargement of gallbladder:3/11 cases.

1980-06-01

344

Heterotopic pregnancy: Sonographic findings  

International Nuclear Information System (INIS)

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.

1999-03-01

345

Find Us - EEB  

...is a federation of citizens' environmental organisations based in Brussels, Boulevard de Waterloo since 1974'> 'Federation, Brussels, environmental issues, Boulevard ...de Waterloo'> Find Us - EEB EEB Search EEB Intranet Home About EEB How the EEB Works ... de Waterloo, B-1000 Brussels Tel.: +32 2 289 10 90 Fax: +32 2 289 10 99 Email ... de Waterloo, B-1000 Brussels Tel.: +32 2 289 10 90; Fax: +32 2 289 10 99;...

346

CT findings of slilcosis  

International Nuclear Information System (INIS)

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

1996-04-01

347

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.)

1999-08-01

348

A comparison of methods for calculating population exposure estimates of daily weather for health research  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background To explain the possible effects of exposure to weather conditions on population health outcomes, weather data need to be calculated at a level in space and time that is appropriate for the health data. There are various ways of estimating exposure values from raw data collected at weather stations but the rationale for using one technique rather than another; the significance of the difference in the values obtained; and the effect these have on a research question are factors often not explicitly considered. In this study we compare different techniques for allocating weather data observations to small geographical areas and different options for weighting averages of these observations when calculating estimates of daily precipitation and temperature for Australian Postal Areas. Options that weight observations based on distance from population centroids and population size are more computationally intensive but give estimates that conceptually are more closely related to the experience of the population. Results Options based on values derived from sites internal to postal areas, or from nearest neighbour sites – that is, using proximity polygons around weather stations intersected with postal areas – tended to include fewer stations' observations in their estimates, and missing values were common. Options based on observations from stations within 50 kilometres radius of centroids and weighting of data by distance from centroids gave more complete estimates. Using the geographic centroid of the postal area gave estimates that differed slightly from the population weighted centroids and the population weighted average of sub-unit estimates. Conclusion To calculate daily weather exposure values for analysis of health outcome data for small areas, the use of data from weather stations internal to the area only, or from neighbouring weather stations (allocated by the use of proximity polygons, is too limited. The most appropriate method conceptually is the use of weather data from sites within 50 kilometres radius of the area weighted to population centres, but a simpler acceptable option is to weight to the geographic centroid.

Dear Keith BG

2006-09-01

349

Kernicterus: Acute MR imaging findings  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: To investigate the cranial magnetic resonance imaging findings of kernicterus in the acute stage. Material And Methods: Nine neonates who admitted with jaundice, encephalopathy and indirect hyperbilirubinemia (mean, 35.9 mg/dL were prospectively evaluated with cranial magnetic resonance imaging. Pathological signal changes were evaluated paying particular attention to globus pallidus. Results: Six of nine patients demonstrated bilateral, symmetrical, increased signal intensity in the globus pallidus on Tl-weighted imaging in various degrees. These lesions were not apparent on T2-weighted images. In one patient without globus pallidus involvement multiple parenchymal punctate Tl hyperintense lesions consistent with hemorrhage were seen. The magnetic resonance imaging studies of other two patients showed no evidence of abnormality. Conclusion: The involvement of globus pallidus seen as hyperintense on Tl-weighted magnetic resonance imaging, is a common and characteristic finding of acute kernicterus.

Manav, A.

2004-01-01

350

MR findings of spondylolysis  

International Nuclear Information System (INIS)

We reviewed MR images of 50 patients with spondylolisthesis to disclose MR findings of spondylolysis. In almost half of our series, spondylolysis was detected as a low signal intensity band traversing in the pairs interarticularis on both T1 and T2 weighted images. Sagittal images was superior to axial image in detection of the low signal intensity band. In some patients, a focal high signal intensity accompanying the low signal intensity band was considered to be fluid collection within pseudoarthrosis due to spondylolysis on T2-weighted image. (author)

1994-08-01

351

Mineral find highlights cruise  

Science.gov (United States)

Heavy minerals with potential commercial value were discovered last month by the U.S. Geological Survey (USGS) in seafloor deposits off the coasts of Virginia and Georgia. The USGS sent the research vessel J. W. Powell on a 25-day cruise along the East Coast to assess the concentrations of commercially important minerals in that segment of the U.S. Exclusive Economic Zone (EEZ).Assistant Secretary of the Interior Robert Broadbent called the findings of the Powell “promising” and said they served as a “reminder of just how little we do know about the seafloor resources just a few miles offshore.”

Katzoff, Judith A.

352

CT findings of hypersensitivity pneumonitis  

Energy Technology Data Exchange (ETDEWEB)

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).

Kobayashi, Hideo; Matsuoka, Rokuro; Mieno, Tatsuhiko; Kitamura, Satoshi

1989-04-01

353

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

1993-12-01

354

Renal dysplasia: US findings  

Energy Technology Data Exchange (ETDEWEB)

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

Ha, Doo Hoe; Oh, Ki Keun; Jung, Woo Hee; Yoon, Choon Sik; Ahn, Chang Soo; Kim, Myung Joon [Yonsei University College of Medicine, Seoul (Korea, Republic of)

1993-12-15

355

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.

2002-09-01

356

An Automated Method for Characterizing the Relaxedness of Galaxy Clusters  

Energy Technology Data Exchange (ETDEWEB)

Relaxed galaxy clusters are useful tools for probing cosmological parameters like the gas mass fraction of the universe. Selecting relaxed clusters for this purpose can be a time-consuming and subjective task, so we present methods to automate parts of the process. We fit elliptical isophotes to a diverse sample of Chandra cluster data and summarize other methods for quantifying relaxedness which will be included in future work. Analysis of the results of tests from isophote fitting, combined with numerical simulations of cluster structures and comparison to previous classifications will allow us to formulate criteria for selection of relaxed clusters. We find that they tend to have core radii less than approximately 60 kpc from King model fits, shifts in isophote centroids of less than 25 kpc over a range in semi-major axes of several hundred kpc, and significantly greater surface brightness profile gradients within 30 kpc of their cores than unrelaxed clusters. These criteria will help with future cosmological work as larger amounts of cluster data are taken and need objective classification.

George, Matt; /Harvard Coll. Observ. /SLAC

2005-12-15

357

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)

2006-01-01

358

Subdural empyema: CT findings  

Energy Technology Data Exchange (ETDEWEB)

CT scans in 49 patients with surgically proven subdural empyema were evaluated. The empyemas were crescentic or lentiform extra-axial hypodense collections (density approximating that of cerebrospinal fluid) with prominent, sharply etched medial rim enhancement. Enhancement of the adjacent cerebral cortex was identified in many cases. Mass effect was always present and in 10 cases so extensive that it overshadowed a small extra-axial collection. CT allowed for precise localization of the lesion, including contiguous or isolated involvement of the interhemispheric subdural space. Mortality was 12% (6/49 cases), a marked improvement when compared with mortality figures obtained prior to the advent of CT (40%). CT findings indicative of involvement of the adjacent parenchyma via retrograde thrombophlebitis with resultant infarction and/or abscess formation were associated with poor prognosis. Improvement in prognosis since the advent of CT is the direct result of early accurate diagnosis and timely intervention.

Zimmerman, R.D.; Leeds, N.E.; Danziger, A.

1984-02-01

359

Subdural empyema: CT findings  

International Nuclear Information System (INIS)

CT scans in 49 patients with surgically proven subdural empyema were evaluated. The empyemas were crescentic or lentiform extra-axial hypodense collections (density approximating that of cerebrospinal fluid) with prominent, sharply etched medial rim enhancement. Enhancement of the adjacent cerebral cortex was identified in many cases. Mass effect was always present and in 10 cases so extensive that it overshadowed a small extra-axial collection. CT allowed for precise localization of the lesion, including contiguous or isolated involvement of the interhemispheric subdural space. Mortality was 12% (6/49 cases), a marked improvement when compared with mortality figures obtained prior to the advent of CT (40%). CT findings indicative of involvement of the adjacent parenchyma via retrograde thrombophlebitis with resultant infarction and/or abscess formation were associated with poor prognosis. Improvement in prognosis since the advent of CT is the direct result of early accurate diagnosis and timely intervention

1984-01-01

360

CT findings in mucopolysaccharidoses  

International Nuclear Information System (INIS)

The CT findings for four patients with mucopolysaccharidosis were analyzed using a Delta scan-25 (Ohio Nuclear). In three cases of Hunter's syndrome (MPS IIA 13-year-old male, MPS IIB 12-year-old male, and 25-year-old male), a dilatation of the cortical sulci was observed. Moderate dilatations were also seen in the basal cistern, the quadrigeminal cistern, and the ambient cistern. In one case of Hunter's syndrome, a low-density area was observed in the bilateral tharamic regions. An irregular low-density area was also seen in the white matter in some cases. PVL was not apparent in any case. Marked ventricular dilations were observed in cases with mental retardation, for example, in one case of Hurler's syndrome (8-year-old male) and one case of MPS IIA. The circulation and absorbtion of CSF in cortical snbarachnoid spaces were supposed to be moderately retarded by metrizamide CT cisternography. (author)

1981-01-01

 
 
 
 
361

Trochanteric bursitis: radiological findings  

International Nuclear Information System (INIS)

To describe the radiological findings associated with trochanteric bursitis. Six patients studied by means of plain radiography (n=6), CT(n=4) and MR(n=2). The conventional radiography study was normal in two patients and disclosed bone abnormalities in four. US showed a hypoechoic or anechoic collection in all the patients. Two patients presented areas suggestive of calcification, and septa were observed in one. CT disclosed the presence of well defined, low-attenuation, unenhanced collections. MR images identified collections with a signal intensity similar to that of water. Trochanteric bursitis is a relatively common cause of hip pain, and can involve any one of a number of etiologies. US is a good imaging technique for diagnosing this pathology. (Author) 10 refs

1997-01-01

362

Aortographic findings of Takayasu's arteritis  

International Nuclear Information System (INIS)

Takayasu's arteritis is a stenosing inflammatory process of unknown etiology affecting not only the aortic arch and its branches, but also the abdominal aorta, its branches and the pulmonary arteries. During the period from August 1971 to August 1973, 9 cases with Takayasu's arteries have been observed in the Seoul National University Hospital. The diagnosis was mainly based upon the aortography, which is the only practical method of delineating the extent and nature of the vascular involvement. The purpose of this paper is describe and analyze the radiographic findings, especially aortographic aspect. The results obtained are as follows: 1. The 9 cases are all female and two thirds are under 30 years of age. Headache, dizziness, absent or weak radial pulse and hypertension are the most common symptoms and signs. The laboratory data are generally unremarkable, except elevation of E.S.R. and gamma globulin fraction on electrophoresis. 2. Conventional roentgenography of the chest may be helpful but not specific in diagnosis of Takayasu's arteritis. 3. The aortographic findings are characteristic and pathognomonic in diagnosis of Takayasu's arteritis. In our cases, the most common findings are stenosis or occlusion of subclavian artery, diffuse narrowing with irregular contour of descending aorta, renal artery involvement, narrowing and aneurysmal dilatation of abdominal aorta, and multiple sites involvement. 4. Therefore, value of total aortography was stressed

1973-12-01

363

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

1999-09-01

364

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

365

Finding Communities of Related Genes  

CERN Document Server

We present an automated method of identifying communities of functionally related genes from the biomedical literature. These communities encapsulate human gene and protein interactions and identify groups of genes that are complementary in their function. We use graphs to represent the network of gene cooccurrences in articles mentioning particular keywords, and find that these graphs consist of one giant connected component and many small ones. In addition, the vertex degree distribution of the graphs follows a power law, whose exponent we determine. We then use an algorithm based on betweenness centrality to identify community structures within the giant component. The different structures are then aggregated into a final list of communities, whose members are weighted according to how strongly they belong to them. Our method is efficient enough to be applicable to the entire Medline database, and yet the information it extracts is significantly detailed, applicable to a particular problem, and interesting...

Wilkinson, D; Wilkinson, Dennis; Huberman, Bernardo A.

2002-01-01

366

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

367

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)

1985-01-01

368

CT findings in mucopolysaccharidoses  

Energy Technology Data Exchange (ETDEWEB)

The CT findings for four patients with mucopolysaccharidosis were analyzed using a Delta scan-25 (Ohio Nuclear). In three cases of Hunter's syndrome (MPS IIA 13-year-old male, MPS IIB 12-year-old male, and 25-year-old male), a dilatation of the cortical sulci was observed. Moderate dilatations were also seen in the basal cistern, the quadrigeminal cistern, and the ambient cistern. In one case of Hunter's syndrome, a low-density area was observed in the bilateral tharamic regions. An irregular low-density area was also seen in the white matter in some cases. PVL was not apparent in any case. Marked ventricular dilations were observed in cases with mental retardation, for example, in one case of Hurler's syndrome (8-year-old male) and one case of MPS IIA. The circulation and absorbtion of CSF in cortical subarachnoid spaces were supposed to be moderately retarded by metrizamide CT cisternography.

Tsuchida, T.; Nemoto, S.; Futiwara, K.; Hayakawa, I. (Bokuto Municipal Hospital, Tokyo (Japan)); Nihei, K.

1981-02-01

369

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

1991-12-01

370

Findings of autopsy imaging  

International Nuclear Information System (INIS)

Described is the outline of autopsy imaging (Ai) by CT, MRI and ultrasonography (US) as the reading of the postmortem images is becoming important for radiologist on site. The present major Ai modality is CT, where the cause of death can be identified in most cases of injuries like that by traffic accident, and of intracranial hemorrhagic lesions. It is difficult for CT alone to determine the cause due to acute heart failure, for which Ai by enhanced CT (2-min heart massage during the intravenous infusion of a contrast agent) has been introduced. CT findings in Ai are varied according to the death cause, anabiotic treatment conducted and postmortem changes. The second item includes the gastrointestinal tract dilation, rib fracture, pneumo- or hemo-thorax, bruise or rupture, and intravascular gas, and the third, the blood hypostasis, which emphasizing the shadow at the gravity-loaded portions in Ai CT. MRI signals vary dependently on the temperature and the inversion time should be shortened to suppress the cerebrospinal signal at Ai of the cold body like that stored in a refrigerator. US can detect clear, macroscopic morphological changes and the portable machine has been in practice at autopsy onsite. As sound speed depends on the temperature in water, Ai US images are obscure relative to living body due to the low temperature. Authors think the problem to identify the cause of death will be mostly solved in Japan when radiological technologists more actively participate in Ai. (K.T.)

2009-05-01

371

Tomography finds waste sites  

Science.gov (United States)

Geophysical diffraction tomography (GDT), a remote sensing method, is being developed for hazardous waste site characterization by researchers at Oak Ridge National Laboratory, Tenn., with the support of the U.S. Army Toxic and Hazardous Materials Agency, Aberdeen Proving Ground, Md.More accurate assessment of hazardous sites translates into more efficient and less costly cleanup efforts by defining parameters such as waste site boundaries, geophysical site characteristics, buried container leakage, and hazardous material migration. Remote sensing devices eliminate the potential for environmental damage, safety hazards, or high costs associated with intrusive site characterization techniques.

Bush, Susan M.

372

CT findings of automastoidectomy  

International Nuclear Information System (INIS)

Cholesteatoma of the middle ear and mastoid sometimes destroys the posterior wall of the external auditory canal(EAC), and this phenomenon is termed as 'automastoidectomy'. During the past two years the authors reviewed the CT features of automastoidectomy in eight patients with middle ear cholesteatoma, There was a variable amount of the cholesteatomatous mass or debris within the mastoid cavity in all patients, of whom air collection was found in four. Interestingly, the site and pattern of the erosion of the EAC were nearly identical between patients with air in the mastoid cavity and those without it. Air in the mastiod cavity was the only clue of the expulsion of the cholesteatoma. So, we think that the expulsion of the cholesteatoma might be predicted when the erosion of the EAC is present in patients with cholesteatoma in the mastoid cavity. CT clearly depicted associated complications caused by the cholesteatoma, such as ossicular destruction (n=8), the erosion of the facial nerve canal (n=2), the erosion of the lateral semicircular canal (n=2), the erosion of the tegmen (n=1), the erosion of the sigmoid sinus plate (n=1), the erosion of the superior semicircular canal (n=1), and the erosion of the vestibule (n=1). Although much of the natural history of the middle ear cholesteatoma still remains to be determined, we thick that careful evaluation of one type of possible progression of the disease will help us understand its clinical course. Moreover, our findings strongly support the use of CT for evaluation of 'automastoidectomy' seen in many cases of cholesteatoma

1992-01-01

373

CT findings of automastoidectomy  

Energy Technology Data Exchange (ETDEWEB)

Cholesteatoma of the middle ear and mastoid sometimes destroys the posterior wall of the external auditory canal(EAC), and this phenomenon is termed as 'automastoidectomy'. During the past two years the authors reviewed the CT features of automastoidectomy in eight patients with middle ear cholesteatoma, There was a variable amount of the cholesteatomatous mass or debris within the mastoid cavity in all patients, of whom air collection was found in four. Interestingly, the site and pattern of the erosion of the EAC were nearly identical between patients with air in the mastoid cavity and those without it. Air in the mastiod cavity was the only clue of the expulsion of the cholesteatoma. So, we think that the expulsion of the cholesteatoma might be predicted when the erosion of the EAC is present in patients with cholesteatoma in the mastoid cavity. CT clearly depicted associated complications caused by the cholesteatoma, such as ossicular destruction (n=8), the erosion of the facial nerve canal (n=2), the erosion of the lateral semicircular canal (n=2), the erosion of the tegmen (n=1), the erosion of the sigmoid sinus plate (n=1), the erosion of the superior semicircular canal (n=1), and the erosion of the vestibule (n=1). Although much of the natural history of the middle ear cholesteatoma still remains to be determined, we thick that careful evaluation of one type of possible progression of the disease will help us understand its clinical course. Moreover, our findings strongly support the use of CT for evaluation of 'automastoidectomy' seen in many cases of cholesteatoma.

Kim, Hyung Jin; Chung, Hae Gyeong; Kim, Jae Hyoung; Hwang, Eui Gee; Ma, Yong Woon; Chung, Sung Hoon [College of Medicine, Gyeongsang National University, Jinju (Korea, Republic of)

1992-01-15

374

The color doppler ultrasonography findings of leptospirosis  

International Nuclear Information System (INIS)

Objective: To study the color ultrasonography findings of leptospirosis. Methods: The color ultrasonography findings of heart, liver, spleen, kidney, lymph node and gastrocnemius in 51 cases of leptospirosis were studied retrospectively. Results: Changes of the color ultrasonography findings were showed in all cases. The changes of liver, kidney, lymph node and gastrocnemius were conspicuous, and the positive rates were 62%, 47%, 88% and 90%. Conclusion: Changes of the color ultrasonography findings of heart, liver, spleen, kidney, lymph node and gastrocnemius can be found in leptospirosis cases, without specificity. (authors)

2009-08-01

375

Finding physics signals with event deconstruction  

CERN Document Server

We develop a matrix element based reconstruction method called event deconstruction. The method uses information from the hard matrix element and a parton shower to assign probabilities to whether a final state was initiated by a signal or background process. We apply this method in the signal process of a Z' decaying to boosted top quarks in an all hadronic final state and discuss envisioned improvements of the method. We find that event deconstruction can considerably improve on existing reconstruction techniques.

Soper, Davison E

2014-01-01

376

Finding physics signals with event deconstruction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We develop a matrix element based reconstruction method called event deconstruction. The method uses information from the hard matrix element and a parton shower to assign probabilities to whether a final state was initiated by a signal or background process. We apply this method in the signal process of a Z' decaying to boosted top quarks in an all hadronic final state and discuss envisioned improvements of the method. We find that event deconstruction can considerably impr...

Soper, Davison E.; Spannowsky, Michael

2014-01-01

377

Presentation of findings  

International Nuclear Information System (INIS)

The conference served an important purpose in bringing together and consolidating information on the termination of nuclear practices from around the world, and the Proceedings will therefore represent a very valuable overview of the current situation. I should add, however, that the information presented at the conference was concentrated on the decommissioning of large nuclear facilities. A concerted international effort should be made to obtain a realistic picture of the scope of the decommissioning task to be expected from the many other practices using radioactive material, for example in medical, industrial and research applications. In this regard, one notes that the IAEA is currently compiling information on the magnitude of this problem, and urge it to continue with this work. This should provide a solid basis for an international discussion of actions to begin solving the problem. A great deal of practical decommissioning experience that has been accumulated was presented at the conference.The international community should consider ways to make this information more widely available. The IAEA could contribute to this by means of a Web-based chat room dedicated to decommissioning. One conclusion from the discussion was that the IAEA should ensure that its safety standards on decommissioning are reviewed, improved and updated, and provide more detailed guidance on practical issues. Turning to the main findings from Sessions 2.A - 2.E, six major topics emerged: the importance of early and thorough planning; social issues; funding; waste management issues; long term retention of knowledge; and the removal of regulatory controls. With regard to the issue of early planning for decommissioning, emphasis was placed during the conference on the importance of planning decommissioning thoroughly. Planning should start as early as possible, ideally at the design stage of a facility, as required by the Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management. The overall decommissioning strategy to be adopted should be identified as early as possible in the planning process. The presentations and discussions at this conference indicated a distinct shift towards immediate dismantling as a preferred strategy. Turning to social issues, the participation of the public, including community leaders, work forces and interest groups, in the decision making processes should be initiated as early as possible and should continue throughout the process. The aim is to minimize the negative social and economic effects of decommissioning. In the discussion on waste management issues, it was noted that there was progress on the provision of national repositories for radioactive waste would be of great benefit to decommissioning. The long term retention of knowledge is of great importance in two respects: people and records. Funding is clearly vital to decommissioning. Provision needs to be made to ensure that sufficient funds will be available, with a high degree of confidence, when they are needed. An appropriate mechanism should be in place before a new facility is licensed to operate. With regard to the removal of regulatory controls, it was noted that the recycling or reuse of materials from decommissioning can greatly reduce the amount of waste that needs to be disposed of in a repository.This can preserve resources and repository capacity. Criteria for the international trade in such materials are needed, and therefore should be internationally agreed. A great deal of work has been done aimed at establishing criteria for the removal of materials from regulatory control.Work aimed at reaching international consensus on an acceptable methodology, including codes and scenarios, for establishing clearance levels should continue. Questions remain as to whether the criteria for the release of sites should be the same as those for materials, whether natural and artificial radionuclides can be subject to the same criteria, and whether there is a market for materials released from a nuclear fa

2003-08-01

378

Finding Ernst Mayr's Plato.  

Science.gov (United States)

Many biologists have accepted Ernst Mayr's claim that evolutionary biology undermined an essentialist or typological view of species that had its roots in Platonic philosophy. However, Mayr has been accused of failing to support with textual evidence his attributions to Plato of these sorts of views about biology. Contemporary work in history and philosophy of biology often seems to take onboard Mayr's account of Plato's view of species. This paper seeks to provide a critical account of putative inconsistencies between an evolutionary view of species and Platonic philosophy with renewed attention to the Platonic texts in light of recent Plato scholarship; I argue that claims that Plato held an essentialist view of species inconsistent with evolutionary biology are inadequately supported by textual evidence. If Mayr's essentialist thesis fails, one might think that the intuition that Platonic philosophy is in tension with Darwinian evolution could nonetheless be accounted for by Plato's apparent privileging of a certain sort of teleological explanation, a thesis that Mayr suggests in his 1959 paper on Louis Agassiz. However, this thesis also faces difficulties. Ernst Mayr's Plato is more likely to be found in the writings of anti-evolutionary 19th century biologists like Mayr's frequent target, Agassiz, than in a cautious reading of the Platonic dialogues themselves. Interlocutors in discussions of the history of biological thought and classificatory methods in biology should be cautious in ascribing views about biology to Plato and using terms like "Platonic essentialism." PMID:24135002

Powers, Jack

2013-12-01

379

Hippocampal malrotation: MRI findings  

International Nuclear Information System (INIS)

Purpose: To demonstrate the common features of hippocampus malrotation in patients with epilepsy by volumetric and high-resolution MRI. Material and methods: MRI study was performed in 5 patients (2 females and 3 males) ages ranged between 6-41 years (average: 25 years), all of them with epilepsy diagnosis. MRI was performed with a 1.5 T (GE Signa). The epilepsy protocol include sagittal T1, axial T1 and T2, coronal FLAIR, coronal T2 (high-resolution) and volumetric 3D SPGR IR 1.5 mm thick sequences. Results: The common features found in all patients were: a) Incomplete inversion and round configuration of the hippocampus; b) Unilateral affectation; c) Variable affectation of the hippocampus; d) Normal signal intensity; e) Modification of the inner structure of the hippocampus; f) Abnormal angularity of the collateral sulcus; g) Abnormal position and size of the fornix; h) Normal size of the temporal lobe; and i) Enlargement of the temporal horn with particular configuration. Conclusion: Hippocampus malrotation is a malformation that should be included in the differential diagnosis of the epilepsy patients. MRI provides accurate information for the diagnosis. (author)

2001-01-01

380

Sonographic Findings of Human Fascioliasis  

Directory of Open Access Journals (Sweden)

Full Text Available Background/Objective: Ultrasonography is an imaging modality which is easy to use and less expensive than other imaging methods. It is becoming more widely available in regions of the world where Fasciola hepatica infestation is prevalent. In this report, we described the sonographic findings of hepatic lesions in patients with fascioliasis. Patients and Methods: In this cross-sectional study, 248 patients with confirmed hepatic fascioliasis from Guilan province who were referred by internists or infectious disease specialists to private sonographic offices were studied. Abdominal sonography was performed in supine and left decubitus positions using an Aloka 288 scanner and a 3.5 MHz transducer. Results: Out of 176 hepatobiliary involvement, the right lobe of liver and the periportal area with echoic or hypoechoic lesions, had the most involvement (45.2%. There were lesions in the gallbladder of 34 (13.7% and biliary tracts of 17 (7% patients. There was coincident in-volvement of both liver and biliary tracts in 13 (5.2% patients. Conclusion: Sonography is a useful method to confirm hepatobiliary lesions in human fascio-liasis and can facilitate the diagnosis of this condition, particularly in areas where it is endemic.

F. Mansour Ghanaei

2006-08-01

 
 
 
 
381

MRI findings of vermian medulloblastoma  

International Nuclear Information System (INIS)

To find characteristic MRI features of vermian medulloblastoma. Materials and methods; MRI studies and medical records were retrospectively reviewed for 12 patients with surgically proven midline medulloblastoma. The assessment concerned appearance of the mass in relation to surrounding structures: MR signal intensity; the enhancement pattern; the mass's location and size: presence of a cystic/necrotic area, calcification, or vascular void: extension through the foramen Luschka: degree of hydrocephalus: and presence of tonsillar herniation. The midline medulloblastoma commonly showed roundish moon-surface appearance, especially on the axial T2-weighted images. All tumors showed heterogeneous signal intensities mainly due to intratumoral cystic/necrotic or hemorrhagic changes. The tumors were commonly located at mid-and/or inferior vermis. Occasionally the tumors extended through the foramen Luschka, and caused obstructive hydrocephalus of moderate to severe degree. Post-contrast study showed heterogeneous, dense contrast enhancement in the majority of patients. The MR finding of the moon-surface appearance formed by both the mass and the intratumoral cystic/necrotic change as seen on axial T2-weighted images could be helpful in the diagnosis of vermian medulloblastoma

1996-01-01

382

Ultrasonographic findings of ovarian tumors  

International Nuclear Information System (INIS)

The ultrasound is easily available and noninvasive diagnostic method without radiation hazard. We can approach to differential diagnosis of ovarian tumors by gray scale ultrasound which can display the detailed structure of soft tissue. In department of radiology, Korea Veterans Hospital, 27 cases of histologically confirmed ovarian tumors collected from March 1984 to February 1986 were analyzed. The results were as follows: 1. The age distribution was from 13 to 72 years. 2. The histologic diagnosis of ovarian tumors (27 cases) are as follows; teratoma (14), mucinous cystadenoma (8), mucinous cystadenocarcinoma (1), serous cystadenoma (2), Krukenburg tumor (1) and malignant thecoma (1). 3. The long diameter of ovarian tumors ranges from 4 cm to 28 cm. In these, mucinous cystadenoma is the largest and their size are as follows; less than 10 cm; 25%, 11-15 cm; 12%, 16-20 cm; 25% and more than 20 cm; 38%. 4. The ultrasonographic findings of teratoma (14) were mainly cystic (8) or echogenic (6). There were echogenic solid components showing distal acoustic shadowing or fat-fluid level within cystic masses. Echogenecity of solid masses was heterogenous. 5. The ultrasonographic findings of mucinous cystadenoma and cystadenocarcinoma (9) were unilocular cystic (3) or multilocular cystic (6). There were variable amount of echogenic component within cystic masses. 6. Those of serous cystadenoma (2) were unilocular cystic (1) or multilocular cystic (1). 7. Krukenburg tumor (1) and Malignant thecoma (1) were heterogenously echogenic.

1986-10-01

383

Ultrasonographic findings of ovarian tumors  

Energy Technology Data Exchange (ETDEWEB)

The ultrasound is easily available and noninvasive diagnostic method without radiation hazard. We can approach to differential diagnosis of ovarian tumors by gray scale ultrasound which can display the detailed structure of soft tissue. In department of radiology, Korea Veterans Hospital, 27 cases of histologically confirmed ovarian tumors collected from March 1984 to February 1986 were analyzed. The results were as follows: 1. The age distribution was from 13 to 72 years. 2. The histologic diagnosis of ovarian tumors (27 cases) are as follows; teratoma (14), mucinous cystadenoma (8), mucinous cystadenocarcinoma (1), serous cystadenoma (2), Krukenburg tumor (1) and malignant thecoma (1). 3. The long diameter of ovarian tumors ranges from 4 cm to 28 cm. In these, mucinous cystadenoma is the largest and their size are as follows; less than 10 cm; 25%, 11-15 cm; 12%, 16-20 cm; 25% and more than 20 cm; 38%. 4. The ultrasonographic findings of teratoma (14) were mainly cystic (8) or echogenic (6). There were echogenic solid components showing distal acoustic shadowing or fat-fluid level within cystic masses. Echogenecity of solid masses was heterogenous. 5. The ultrasonographic findings of mucinous cystadenoma and cystadenocarcinoma (9) were unilocular cystic (3) or multilocular cystic (6). There were variable amount of echogenic component within cystic masses. 6. Those of serous cystadenoma (2) were unilocular cystic (1) or multilocular cystic (1). 7. Krukenburg tumor (1) and Malignant thecoma (1) were heterogenously echogenic.

Kwon, Yang Sook; Kim, Soo Han; Kim, Seung Hyup; Shin, Hyun Ja [Korea Veterans Hospital, Seoul (Korea, Republic of)

1986-10-15

384

Congenital mediastinal cysts: imaging findings  

International Nuclear Information System (INIS)

Congenital mediastinal cysts are uncommon benign lesions generally caused by an abnormal embryological development of the foregut or coelomic cavity. They are expansive lesions, frequently asymptomatic that may manifest as a result from compression of adjacent structures. Bronchogenic, pericardial, enteric, thymic, esophageal duplication cysts and lymphangiomas are the main entities in this group of lesions. Congenital mediastinal cysts morphology is typical and imaging methods allow a correct diagnosis in a great number of cases. Surgical treatment is indicated only in cases of symptomatic lesions, considering that these lesions present no potential for malignant degeneration. The present study was aimed at commenting and illustrating the most relevant imaging findings of these lesions based on a retrospective review of ten cases collected in the records of the involved institutions. (author)

2009-01-01

385

Primary thyroid lymphoma: CT findings  

Energy Technology Data Exchange (ETDEWEB)

Introduction: To evaluate the computed tomographic (CT) findings of primary thyroid lymphoma. Methods and material: The clinicopathological data and CT images of nine patients with primary thyroid lymphoma were retrospectively reviewed. The CT appearances were classified into three types: type 1, a solitary nodule surrounded by normal thyroid tissue; type 2, multiple nodules in the thyroid, and type 3, a homogeneously enlarged both thyroid glands with a reduced attenuation with or without peripheral thin hyperattenuating thyroid tissue. Results: All patients had a rapidly enlarging thyroid mass and coexistent Hashimoto's thyroiditis. One patient showed type 1 pattern, three type 2, and five type 3. Six patients had homogeneous tumor isoattenuating to surrounding muscles. The tumors had a strong tendency to compress normal remnant thyroid and the surrounding structure without invasion. Conclusion: Primary thyroid lymphoma should be included in the differential diagnosis when old female had a homogeneous thyroidal mass isoattenuating to muscles, which does not invade surrounding structures.

Kim, Hyo-Cheol; Han, Moon Hee E-mail: hanmh@radcom.snu.ac.kr; Kim, Keon Ha; Jae, Hwan Jun; Lee, Sang Hyun; Kim, Sam Soo; Kim, Kwang Hyun; Chang, Kee-Hyun

2003-06-01

386

Arthroscopic findings after shoulder dislocation  

Directory of Open Access Journals (Sweden)

Full Text Available Background/Aim. Recurrent instability of the shoulder joint is frequently difficult to differentiate from diseased or injured rotator cuff or tendon of the forearm flexor (m. biceps brachii. Shoulder joint arthroscopy has been only recently introduced into instable shoulder joint lesion examination. The aim of this study was to present and analyze an arthroscopic finding on instable shoulder joint in order to determine causes and mechanisms of instability, as well as principles of surgical treatment. Methods. Arthroscopy of the shoulder joint was performed in 158 patients with at least one documented shoulder joint dislocation. These patients were divided into two groups. The group I included the patients with one to three dislocations, while the group II those with more than three dislocations. Preoperative diagnosis was based on anamnestic data and clinical examination using specific tests, and on the diagnosis of shoulder joint using radiography or computed tomography. Results. Out of the total number of the patients 138 (87.34% had injury of the anterior patellar brim, 119 (75.32% had failure of the anterior capsule, 126 (79.75% had compressive cartilage injury of the posterior part of the head of the upper arm bone (Hill-Sachs lesion, 102 (64.56% had insufficiency of glenohumeral tendon, 11 (6.96 had complete cut of the rotator cuff, 23 (14.56% had injury of the posterior patellar brim, 12 (7.59% had injury of the upper anterior-posterior patellar brim (SLAP. Conclusion. According to the obtained results it could be concluded that there is no a unique injury that leads to shoulder joint instability. It is necessary to point out to the significance of anamnesis and clinical examination in making diagnosis. Arthroscopic diagnostics is indicated in clinically unreliable findings as an additional method for determining operative treatment.

Medenica Ivica

2009-01-01

387

Subungual glomus tumors: imaging findings  

International Nuclear Information System (INIS)

Objective: to evaluate main imaging findings of subungual glomus tumors. Materials and methods: retrospective study of eight cases of subungual glomus tumors from the archives of two private clinics in Goiania, GO, Brazil. Plain radiographs were obtained in five cases, Doppler ultrasonography in five, and magnetic resonance imaging in five cases. Results: mean age of the patients included in the present study was 39 years, with female predominance (7:1). Tumors didn't present prevalence in any specific finger and in most of cases the tumor was located in the medial subungual region. Plain radiography was positive in five cases, demonstrating pressure erosion. Doppler ultrasonography was positive in five cases, demonstrating a hypoechoic and hyper vascularized solid nodule. Magnetic resonance imaging was positive in all of the cases, showing a solid nodule, hypointense on T1-, hyperintense on T2-weighted image, with homogeneous contrast uptake. All the patients underwent surgical excision of the lesion with histopathological confirmation. Conclusion: in most of cases, glomus tumors are subungual. The diagnosis is clinical and generally is lately achieved. Imaging methods are useful tools for the early diagnosis besides aiding in the surgical planning, considering that the treatment of choice is surgical excision (author)

2009-01-01

388

Finding Flow Experience in Music Activity  

Directory of Open Access Journals (Sweden)

Full Text Available This research is aim to describe how one finding flow experience in his music activity, experiencing flow and feeling the impact of flow experience to his music career and life. The research method used is qualitative, intrinsic study case. The participants are two famous jazz musicians in Bandung, West Java, Indonesia. Data collecting used are in-depth interview, participant observation and document. The result shows that participant who has environment support especially from his music teacher is not only easier to find and experience flow, but also find happiness as impact of his flow experience. On the other hand, another participant who doesn’t have environment support especially from his family and have personality disposition to use his cognition, is struggling to find his flow experience in playing music, but then he finally find it when composing music.

Dewi Sartika

2014-03-01

389

Finding an Eye Care Professional  

Science.gov (United States)

... an Eye Care Professional Finding an Eye Care Professional Finding an Eye Care Professional PDF* The National ... website can be addressed to the NEI Website Manager . NIH...Turning Discovery Into Health ®

390

CT findings of Wilson's disease  

International Nuclear Information System (INIS)

Thirteen cases of Wilson's disease were examined by computerized tomography. Two of them were latent cases. The other 11 were typical cases with a Kayser-Fleisher ring and neurological signs, and in which the ceruloplasmin level in serum was low. The caudate heads were measured by Barr's method using two ratios, FH/CC and CC/OT. The CT findings were as follows: (1) caudate head atrophy (10 cases), (2) cerebral atrophy and/or ventricular dilatation (7 cases), (3) symmetrical low density of thalamus (3 cases), (4) symmetrical low density of pallidum (2 cases), (5) low density of midbrain (2 cases), (6) symmetrical low density of putamen (1 case), (7) pons atrophy (1 case), (8) cerebellar atrophy (1 case), (9) low density of r-temporal area (1 case). All of them except for the two latent cases showed some abnormal findings on CT. Only one symptomatic case showed no caudate atrophy one year after the onset, though two other cases already showed marked atrophy after only 10 months. It was stressed that the low-density lesions in the thalamic area were found with a high frequency. There was no correlation between the duration of illness and the degree of caudate atrophy among the patients with Wilson's disease as compared with those with Huntington's chorea. As in a previous study of pneumoencephalography, we failed also to distinguish the two diseases by measuring the ratios on CT films. It may be valuable to study the progression of the CNS lesions of Wilson's disease by using CT repeatedly. (author)

1980-01-01

391

HEMATOLOGIC FINDINGS IN OPERATING ROOM STAFFS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Introduction. Long term exposure to trace amounts of anesthetic vapors and gases may produce hematologic and hepatic disorders in human. Since operating room (OR) staffs are exposed to these agents, we decided to study their hematopoietic and hepatic systems in comparison with ordinary ward staffs. Methods. Seventy staffs from OR were compared with a matched similar number of ward staffs about their hematologic and hepatic laboratory findings in a historical cohort study. Findings. ...

Soltani, H.; Saghaei, H.

2000-01-01

392

Method for finding firing sequences for the reachability problem of Petri nets with mathematical programming technique; Suri keikakuho ni yoru petri net no katatsu mondai ni okeru hakka keiretsu no sosaku shuho  

Energy Technology Data Exchange (ETDEWEB)

This paper describes a method to expand a matrix equation so that a firing condition in transition can be considered and search the firing sequences in the reachability problem of Petri nets. An attempt has been made to formulate a firing sequence searching problem as a complete integer solution planning problem, and contract it by using a kind of negative-state enumeration method. Effectiveness of this method was discussed through simple numerical examples. This method would allow efficient search of a systematized firing sequence, using partial assembly of reachable markings as the object. The proposed method of contracting the firing sequence searching problem is based on a linearity planning method that can solve a problem with an amount of calculation in the order of multiple term formula for the size of the problem. However, if the size of the subject Petri net grows larger to a certain extent, it is not possible to avoid remarkable increase in the required calculation time and memory capacity. It is intended to discuss, while considering these points, further improvement in the efficiency of this method, such as introduction of an analysis method of the large-size linearity planning problem. 9 refs., 1 fig., 1 tab.

Fujii, Y.; Sekiguchi, Y. [Yokohama National University, Yokohama (Japan)

1996-01-20

393

The multidimensional evaluation and treatment of anxiety in children and adolescents: rationale, design, methods and preliminary findings Avaliação multidimensional e tratamento da ansiedade em crianças e adolescentes: marco teórico, desenho, métodos e resultados preliminares  

Digital Repository Infrastructure Vision for European Research (DRIVER)

OBJECTIVE: This study aims to describe the design, methods and sample characteristics of the Multidimensional Evaluation and Treatment of Anxiety in Children and Adolescents - the PROTAIA Project. METHOD: Students between 10 and 17 years old from all six schools belonging to the catchment area of the Primary Care Unit of Hospital de Clínicas de Porto Alegre were included in the project. It comprises five phases: (1) a community screening phase; (2) a psychiatric diagnostic phase; (3) a multi...

Giovanni Abrahão Salum; Luciano Rassier Isolan; Vera Lúcia Bosa; Andrea Goya Tocchetto; Stefania Pigatto Teche; Ilaine Schuch; Jandira Rahmeier Costa; Marianna de Abreu Costa; Rafaela Behs Jarros; Maria Augusta Mansur; Daniela Knijnik; Estácio Amaro Silva; Christian Kieling; Maria Helena Oliveira; Elza Medeiros

2011-01-01

394

MR findings in intralabyrinthine schwannomas  

International Nuclear Information System (INIS)

AIM: Intralabyrinthine schwannomas (ILS) are rare benign tumours. They are not always recognized on routine magnetic resonance imaging (MRI). We aimed to study the clinical presentation and MRI findings in our patients with ILS. MATERIALS AND METHODS: Retrospective analysis of patients with vestibular schwannomas treated at this center. RESULTS: Of 144 vestibular schwannomas studied at this centre, three patients had an ILS. The most common presenting symptoms were unilateral hearing loss, tinnitus and vertigo. Two patients demonstrated a progressive sensorineural hearing loss (SNHL). The third patient had a severe SNHL at presentation. MRI enhanced with contrast medium was positive in the two patients with progressive SNHL and negative in the patient with the severe SNHL. CONCLUSION: This series demonstrates the ability of MRI to identify schwannomas filling the labyrinth, and also its inability to identify extremely small ILS. It underlines the importance of sending the cristae of patients undergoing labyrinthectomy for presumed Meniere's disease for histological examination. Montague, M.-L. et al. (2002)

2002-05-01

395

MR findings in intralabyrinthine schwannomas  

Energy Technology Data Exchange (ETDEWEB)

AIM: Intralabyrinthine schwannomas (ILS) are rare benign tumours. They are not always recognized on routine magnetic resonance imaging (MRI). We aimed to study the clinical presentation and MRI findings in our patients with ILS. MATERIALS AND METHODS: Retrospective analysis of patients with vestibular schwannomas treated at this center. RESULTS: Of 144 vestibular schwannomas studied at this centre, three patients had an ILS. The most common presenting symptoms were unilateral hearing loss, tinnitus and vertigo. Two patients demonstrated a progressive sensorineural hearing loss (SNHL). The third patient had a severe SNHL at presentation. MRI enhanced with contrast medium was positive in the two patients with progressive SNHL and negative in the patient with the severe SNHL. CONCLUSION: This series demonstrates the ability of MRI to identify schwannomas filling the labyrinth, and also its inability to identify extremely small ILS. It underlines the importance of sending the cristae of patients undergoing labyrinthectomy for presumed Meniere's disease for histological examination. Montague, M.-L. et al. (2002)

Montague, Mary-Louise; Kishore, Ameet; Hadley, Donald M.; O' Reilly, Brian

2002-05-01

396

Correlation of Imaging Findings with Pathologic Findings of Sclerosing Adenosis  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study was to evaluate the mammographic and sonographic findings of pure sclerosing adenosis. We retrospectively reviewed the mammographic and sonographic findings in 40 cases of pure sclerosing adenosis confirmed by core needle biopsy (n = 23), vacuum-assisted biopsy (n = 7), excision biopsy (n = 9), and lumpectomy (n = 1) from January 2002 to March 2010. All imaging findings were analyzed according to the American College of Radiology (ACR) breast imaging reporting and data system (BI-RADS). Radiologic features were correlated with pathologic findings. Although most mammograms showed negative findings (57%), calcification was the most common abnormal finding of sclerosing adenosis. On sonography, the most common finding was a circumscribed oval hypoechoic mass without posterior features (78%). Most masses showed BI-RADS category 3, (75%, 27/36). Five cases showed categories 4 or 5 (14%, 5/36). Most mammographic and sonographic findings of sclerosing adenosis are non-specific and non-pathognomonic, even though sometimes sclerosing adenosis can be radiologically or histopathologically confused with malignancy

Choi, Bo Bae; Shu, Kwang Sun [Chungnam National University Hospital, Daejeon (Korea, Republic of)

2012-03-15

397

On König's root finding algorithms  

DEFF Research Database (Denmark)

In this paper, we first recall the definition of a family of root-finding algorithms known as König's algorithms. We establish some local and some global properties of those algorithms. We give a characterization of rational maps which arise as König's methods of polynomials with simple roots. We then estimate the number of non-repelling cycles König's methods of polynomials may have. We finally study the geometry of the Julia sets of König's methods of polynomials and produce pictures of parameter spaces for König's methods of cubic polynomials.

Buff, Xavier; Henriksen, Christian

2003-01-01

398

Recurrent pseudotumoral hemicerebellitis: neuroimaging findings  

International Nuclear Information System (INIS)

We present the case of a 13-year-old girl with pseudotumoral hemicerebellitis that recurred 22 months after the first episode together with conventional MR imaging findings and diffusion-weighted imaging and MR spectroscopy findings. A mirror pattern of involvement was present with the contralateral hemisphere affected in the second episode. Recurrent hemicerebellitis is unique and recognition of the radiological findings allows accurate diagnosis that can be a challenge clinically. (orig.)

2008-04-01

399

Recurrent pseudotumoral hemicerebellitis: neuroimaging findings  

Energy Technology Data Exchange (ETDEWEB)

We present the case of a 13-year-old girl with pseudotumoral hemicerebellitis that recurred 22 months after the first episode together with conventional MR imaging findings and diffusion-weighted imaging and MR spectroscopy findings. A mirror pattern of involvement was present with the contralateral hemisphere affected in the second episode. Recurrent hemicerebellitis is unique and recognition of the radiological findings allows accurate diagnosis that can be a challenge clinically. (orig.)

Oguz, Kader K. [Hacettepe University, Department of Radiology, Faculty of Medicine, Ankara (Turkey); Haliloglu, Goknur; Topcu, Meral [Hacettepe University, Department of Paediatric Neurology, Faculty of Medicine, Ankara (Turkey); Alehan, Dursun [Hacettepe University, Department of Paediatric Cardiology, Faculty of Medicine, Ankara (Turkey)

2008-04-15

400

Radiological findings in lipoid proteinosis  

International Nuclear Information System (INIS)

Lipoid proteinosis is a rare disease which is known particularly to dermatologists and ear, nose and throat specialists. The characteristic radiological findings were first described in 1943. The findings in the patients examined radiologically in our clinic are illustrated. Typical radiological findings occur in the gastro-intestinal tract and, particularly, in the brain, and computer tomographic pictures are published for the first time. The pathology, clinical features, mode of inheritance and treatment are discussed. (orig.)

1981-01-01