WorldWideScience
 
 
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

Digital centroid-finding electronics for high-rate detectors  

International Nuclear Information System (INIS)

Fast centroid-finding electronics are being developed for a range of position-sensitive gas proportional detectors. Each cathode strip feeds a preamplifier, shaper and a free-running ADC. Increased total count rate is achieved by dividing the detector into several segments with parallel processing that introduces no common dead time. Each segment has central-channel finding logic and event listing realized in a FPGA, followed by a DSP that performs the centroid calculation and histogramming. Measured count-rate per segment exceeds 106 per second, with virtually no dead time

1999-01-01

4

Digital centroid-finding electronics for high-rate detectors  

Energy Technology Data Exchange (ETDEWEB)

Fast centroid-finding electronics are being developed for a range of position-sensitive gas proportional detectors. Each cathode strip feeds a preamplifier, shaper and a free-running ADC. Increased total count rate is achieved by dividing the detector into several segments with parallel processing that introduces no common dead time. Each segment has central-channel finding logic and event listing realized in a FPGA, followed by a DSP that performs the centroid calculation and histogramming. Measured count-rate per segment exceeds 10{sup 6} per second, with virtually no dead time.

Pietraski, P.J.; Zojceski, Z.; Siddons, D.P.; Smith, G.C.; Yu, B. [Brookhaven National Lab., Upton, NY (United States)

1999-08-01

5

Capacitive charge division in centroid finding cathode readouts in MWPCs  

Energy Technology Data Exchange (ETDEWEB)

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

Smith, G.C.; Fischer, J.; Radeka, V.

1987-10-01

6

Capacitive charge division in centroid finding cathode readouts in MWPCs  

Energy Technology Data Exchange (ETDEWEB)

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

Smith, G.C.; Fischer, J.; Radeka, V.

1987-01-01

7

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 memor...

Payman Moallem; ?Aliakbar Shaemi?

8

Enhancing K-Means Algorithm with Semi-Unsupervised Centroid Selection Method  

Directory of Open Access Journals (Sweden)

Full Text Available The k-means algorithm is one of the frequently used clustering methods in data mining, due to its performance in clustering massive data sets. The final clustering result of the kmeans clustering algorithm is based on the correctness of the initial centroids, which are selected randomly. The original k-means algorithm converges to local minimum, not the global optimum. The k-means clustering performance can be enhanced if the initial cluster centers are found. To find the initial cluster centers a series of procedure is performed. Data in a cell is partitioned using a cutting plane that divides cell in two smaller cells. The plane is perpendicular to the data axis with very high variance and is intended to minimize the sum squared errors of the two cells as much as possible, while at the same time keep the two cells far apart as possible. Cells are partitioned one at a time until the number of cells equals to the predefined number of clusters, K. The centers of the K cells become the initial cluster centers for K-means. In this paper, an efficient method for computing initial centroids is proposed. A Semi Unsupervised Centroid Selection Method is used to compute the initial centroids. Gene dataset is used to experiment the proposed approach of data clustering using initial centroids. The experimental results illustrate that the proposed method is vey much apt for the gene clustering applications.

R. Shanmugasundaram; S. Sukumaran

2010-01-01

9

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; ?Aliakbar Shaemi?

2007-01-01

10

Centroid method: an alternative method of determining coronal curvature in scoliosis. A comparative study versus Cobb method in the degenerative spine.  

UK PubMed Central (United Kingdom)

BACKGROUND CONTEXT: Although the Cobb method is considered the gold standard, the centroid method may offer a reasonable alternative in adult scoliosis because it has better inter- and intraobserver reliabilities in adolescent scoliosis. PURPOSE: To compare the reliabilities of the Cobb and the centroid methods for measuring coronal curvature in degenerative scoliosis in older patients. STUDY DESIGN: Observational study involving three examiners. PATIENT SAMPLE: Sixty whole spine posteroanterior (PA) radiographs were collected. OUTCOME MEASURES: Data were analyzed to determine inter- and intraobserver reliabilities. METHODS: Sixty whole spine PA radiographs of patients older than 60 years were collected to compare the reliabilities of the centroid and the Cobb methods for measuring coronal curvature in degenerative scoliosis. Three examiners using both methods independently measured radiographs twice. Data were analyzed to determine inter- and intraobserver reliabilities. RESULTS: Intraobserver comparisons of all the 60 radiographs revealed that inter- and intraclass correlation coefficients (ICCs) of the Cobb and the centroid methods were both excellent (greater than 0.979 vs. greater than 0.918), and mean absolute differences (MADs) were similar (less than 1.58 vs. less than 2.02). In interobserver comparisons, ICCs of the Cobb method were higher than that of the centroid method (greater than 0.922 vs. greater than 0.799), and the MADs of the Cobb method were lower than that of the centroid method (less than 2.91 vs. less than 4.84). Comparisons of radiographs subdivided by severity showed that the ICCs of the Cobb and the centroid methods were both excellent (greater than 0.819 vs. greater than 0.801), and their MADs were similar (less than 2.29 vs. less than 2.53) for intraobserver comparisons. Interobserver comparisons showed that ICCs and MADs were dependent on the severity of coronal curvature, and the ICCs of the Cobb method (greater than 0.698) were greater than that of the centroid method (greater than 0.507). Furthermore, MAD values for the Cobb method were lower than that for the centroid method (less than 3.59 vs. less than 6.07). Moreover, these results are contradictory to the previous study, which showed the higher reliability of the centroid method in measures of adolescent scoliosis. CONCLUSIONS: In the present study, the reliability of the centroid method was found to be more susceptible to the severity of disease in older patients, despite its demonstrated greater reliability in adolescent scoliosis. Our findings show that the selective use of these two methods in old and young patients can increase the reliabilities of measurements made.

Hong JY; Suh SW; Modi HN; Lee JM; Park SY

2013-04-01

11

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

UK PubMed Central (United Kingdom)

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 B; Samant S; Mittauer K; Lee S; Huang Y; Li J; Kahler D; Liu C

2013-10-01

12

Capacitive charge division in centroid finding cathode readouts in MWPCs. Revision 1/93  

Energy Technology Data Exchange (ETDEWEB)

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

Smith, G.C.; Fischer, J.; Radeka, V.

1987-10-01

13

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

International Nuclear Information System (INIS)

[en] 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

14

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

Energy Technology Data Exchange (ETDEWEB)

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.

Yin Xiaoming; Li Xiang; Zhao Liping; Fang Zhongping

2009-11-10

15

WEDGE-AND-STRIP ANODES FOR CENTROID-FINDING POSITION-SENSITIVE PHOTOM AND PARTICLE DETECTORS  

Energy Technology Data Exchange (ETDEWEB)

We discuss new anode geometries, employing position-dependent charge partitioning, which can be used with microchannel plates, planar proportional counters, and mesh dynode electron multipliers to obtain a two-dimensional position signal from each detected photon or particle. Only three or four anode electrodes and signal paths are required, yet images comprised of a number of detected events have little geometric distortion and the resolution is not limited by thermal noise inherent in resistive sheet anodes. We present an analysis of the geometrical image nonlinearity in the relationship between event centroid location and the charge partition ratios. Fabrication and testing of two wedge-and-strip anode systems are discussed. Images obtained with EUV radiation and microchannel plates that verify the predicted performance of this readout system are shown. We emphasize that the spatial resolution of the wedge-and-strip anode is in no way limited by the coarseness of the anode conductor pattern. The resolution is of the order of 0.4% of the image field size, and could be further improved by adopting low noise signal circuitry. Tradeoffs encountered in the design of practical x-ray, EUV, and charge particle image systems are discussed.

Martin, C.; Jelinsky, P.; Lampto, M.; Malina, R.F.; Anger, H.O.

1981-02-01

16

Wedge-and-strip anodes for centroid-finding position-sensitive photon and particle detectors  

Energy Technology Data Exchange (ETDEWEB)

We discuss new anode geometries, employing position-dependent charge partitioning, which can be used with microchannel plates, planar proportional counters, and mesh dynode electron multipliers to obtain a two-dimensional position signal from each detected photon or particle. Only three or four anode electrodes and signal paths are required, yet images comprised of a number of detected events have little geometric distortion and the resolution is not limited by thermal noise inherent in resistive sheet anodes. We present an analysis of the geometrical image nonlinearity in the relationship between event centroid location and the charge partition ratios. Fabrication and testing of two wedge-and-strip anode systems are discussed. Images obtained with EUV radiation and microchannel plates that verify the predicted performance of this readout system are shown. We emphasize that the spatial resolution of the wedge-and-strip anode is in no way limited by the coarseness of the anode conductor pattern. The resolution is of the order of 0.4% of the image field size, and could be further improved by adopting low noise signal circuitry. Tradeoffs encountered in the design of practical x-ray, EUV, and charge particle image systems are discussed.

Martin, C.; Jelinsky, P.; Lampton, M.; Malina, R.F.; Anger, H.O.

1981-07-01

17

Use of the centroid method of occlusion for studying the vertical and horizontal relationship of the mandible and maxilla.  

UK PubMed Central (United Kingdom)

The aim of the present study was to verify whether the centroid method of occlusion for studying mandibular and maxillary growth enables accurate determination of vertical occlusal patterns (open and deep bite). Lateral cephalograms were obtained of Japanese adult females aged over 18 years of age with a Class II malocclusion (61 open bite and 47 deep bite), or a Class III type open bite (70 subjects) or deep bite (21 subjects) malocclusion. One-way analysis of variance followed by a Bonferroni's t-test was used to compare the results among these four groups. The Deltaabc area, which comprised the palatal, Ar-Gn, and A-B planes, was shown to be significantly larger in the open bite than in the deep bite group for both Class II and Class III malocclusion types (P < 0.01). There was no difference in the Deltaabc area between the Class II and Class III open bite groups or between the Class II and Class III deep bite groups. These findings suggest that the centroid method of occlusion is a versatile diagnostic technique that can accurately differentiate between vertical occlusal patterns of Class II and III types of malocclusion limited to Japanese adult females. The analytical method is also unaffected by gnathostatic differences according to Angle classification.

Murata S

2007-12-01

18

A fast method for computing the centroid of a type-2 fuzzy set.  

UK PubMed Central (United Kingdom)

Type reduction does the work of computing the centroid of a type-2 fuzzy set. The result is a type-1 fuzzy set from which a corresponding crisp number can then be obtained through defuzzification. Type reduction is one of the major operations involved in type-2 fuzzy inference. Therefore, making type reduction efficient is a significant task in the application of type-2 fuzzy systems. Liu introduced a horizontal slice representation, called the ?-plane representation, and proposed a type-reduction method for a type-2 fuzzy set. By exploring some useful properties of the ?-plane representation and of the type reduction for interval type-2 fuzzy sets, a fast method is developed for computing the centroid of a type-2 fuzzy set. The number of computations and comparisons involved is greatly reduced. Convergence in each iteration can then speed up, and type reduction can be done much more efficiently. The effectiveness of the proposed method is analyzed mathematically and demonstrated by experimental results.

Wu HJ; Su YL; Lee SJ

2012-06-01

19

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

20

A walk-free centroid method for lifetime measutement of 207Pb 569.7 keV state  

International Nuclear Information System (INIS)

[en] An improvement have been made in acquiring data of delayed coincidence spectra with ND-620 data acquisition system and off-line data analysis program. The delayed and anti-delayed coincidence spectra can be obtained in one run. The difference of their centroids is the mean lifetime ?. The centroid position of a delayed coincidence spectrum is the zero time of another delayed coincidence spectrum, so the requirement of measuring prompt time spectrum is avoided. The walk of prompt and delayed coincidence spectrum coming from different run are resolved and the walk during the measurement is compensated partly. The delayed coincidence time spectra of 207Pb 569.7 keV state are measured and the half lifetime is calculated via three different methods (slop method, convolution method, centroid shift). The final value of half lifetime is 129.5±1.4ps. THe experimental reduced transition probability is compared with theoretical values

1988-01-01

 
 
 
 
21

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.

2006-01-01

22

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; Xiao-ping Rui; Feng Li

2013-01-01

23

Localization Accuracy Improved Methods Based on Adaptive Weighted Centroid Localization Algorithm in Wireless Sensor Networks  

Directory of Open Access Journals (Sweden)

Full Text Available Generally, see Localization of nodes is a key technology for application of wireless sensor network. Having a GPS receiver on every sensor node is costly. In the past, several approaches, including range-based and range-free, have been proposed to calculate positions for randomly deployed sensor nodes. Most of them use some special nodes, called anchor nodes, which are assumed to know their own locations. Other sensors compute their locations based on the information provided by these anchor nodes. This paper uses a single mobile anchor node to move in the sensing field and broadcast its current position periodically. We provide an adaptive weighted centroid localization algorithm that uses coefficients, which are decided by the influence of mobile anchor node to unknown nodes, to prompt localization accuracy. We also suggest a criterion which is used to select mobile anchor node which involve in computing the position of nodes for improving localization accuracy. The localization accuracy of adaptive weighted centroid localization algorithm is better than maximum likelihood estimation which is used very often.

Chang-Woo Song; Jun-Ling Ma; Jung-Hyun Lee; Kyung-Yong Chung; Kee-Wook Rim

2010-01-01

24

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; Pellumb Kllogjeri

2012-01-01

25

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; Jitendra Agrawal

2010-01-01

26

Depth to the bottom of magnetic sources (DBMS) from aeromagnetic data of Central India using modified centroid method for fractal distribution of sources  

Science.gov (United States)

The depth to the bottom of the magnetic sources (DBMS) has been estimated from the aeromagnetic data of Central India. The conventional centroid method of DBMS estimation assumes random uniform uncorrelated distribution of sources and to overcome this limitation a modified centroid method based on scaling distribution has been proposed. Shallower values of the DBMS are found for the south western region. The DBMS values are found as low as 22 km in the south west Deccan trap covered regions and as deep as 43 km in the Chhattisgarh Basin. In most of the places DBMS are much shallower than the Moho depth, earlier found from the seismic study and may be representing the thermal/compositional/petrological boundaries. The large variation in the DBMS indicates the complex nature of the Indian crust.

Bansal, A. R.; Anand, S. P.; Rajaram, Mita; Rao, V. K.; Dimri, V. P.

2013-09-01

27

Centroid motion in periodically focused beams  

International Nuclear Information System (INIS)

The role of the centroid dynamics in the transport of periodically focused particle beams is investigated. A Kapchinskij-Vladimirskij equilibrium distribution for an off-axis beam is derived. It is shown that centroid and envelope dynamics are uncoupled and that unstable regions for the centroid dynamics overlap with previously stable regions for the envelope dynamics alone. Multiparticle simulations validate the findings. The effects of a conducting pipe encapsulating the beam are also investigated. It is shown that the charge induced at the pipe may generate chaotic orbits which can be detrimental to the adequate functioning of the transport mechanism.

1505-01-00

28

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; A.M. Natarajan

2009-01-01

29

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

2005-01-01

30

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; Xin-Long Luo; Jia-Ru Lin

2011-01-01

31

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

UK PubMed Central (United Kingdom)

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(3) molecule and N(2)H(5) (-) 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(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(2)H(5) (-), 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 M; Fujisaki H

2012-05-01

32

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

33

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

Scientific Electronic Library Online (English)

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

Cini, João Rafael de Moraes; Borsato, Dionísio; Guedes, Carmen Luísa Barbosa; Silva, Hágata Cremasco da; Coppo, Rodolfo Lopes

2013-01-01

34

Optical location of centroids of nonoverlapping objects.  

UK PubMed Central (United Kingdom)

We present an optical technique for finding the centroids of nonoverlapping objects in a scene, thus locating the objects and preserving the underlying advantage of matched filtering approaches to pattern recognition. One is then free to extract any feature desired at these centroid locations rather than restricted to the matched filter test statistic. Furthermore, this allows general feature extraction avoiding prior scene segmentation into individual objects. The technique can also be used for tracking the motion of rigid or nonrigid objects. It consists of cross-correlating the input f(x,y) with a windowed version of the function x + iy and detecting the zeros of the magnitude of the resulting correlation. At these points the x and y first moments vanish. The window is selected based on the size and separation of the objects in a scene. Experimental verification as well as restrictions are also presented.

Freeman MO; Saleh BE

1987-07-01

35

Optical location of centroids of nonoverlapping objects.  

Science.gov (United States)

We present an optical technique for finding the centroids of nonoverlapping objects in a scene, thus locating the objects and preserving the underlying advantage of matched filtering approaches to pattern recognition. One is then free to extract any feature desired at these centroid locations rather than restricted to the matched filter test statistic. Furthermore, this allows general feature extraction avoiding prior scene segmentation into individual objects. The technique can also be used for tracking the motion of rigid or nonrigid objects. It consists of cross-correlating the input f(x,y) with a windowed version of the function x + iy and detecting the zeros of the magnitude of the resulting correlation. At these points the x and y first moments vanish. The window is selected based on the size and separation of the objects in a scene. Experimental verification as well as restrictions are also presented. PMID:20489957

Freeman, M O; Saleh, B E

1987-07-15

36

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

37

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

Energy Technology Data Exchange (ETDEWEB)

The low temperature behavior of the centroid density method of Voth, Chandler, and Miller (VCM) [J. Chem. Phys. {bold 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} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Messina, M.; Schenter, G.K.; Garrett, B.C. [Environmental Molecular Sciences Laboratory, Pacific Northwest Laboratory, Richland, Washington 99352 (United States)

1995-09-01

38

Centroid Bodies and the Logarithmic Laplace Transform - A Unified Approach  

CERN Multimedia

We unify and slightly improve several bounds on the isotropic constant of high-dimensional convex bodies; in particular, a linear dependence on the body's psi-2 constant is obtained. Along the way, we present some new bounds on the volume of L_p-centroid bodies and yet another equivalent formulation of Bourgain's hyperplane conjecture. Our method is a combination of the L_p-centroid body technique of Paouris and the logarithmic Laplace transform technique of the first named author.

Klartag, Bo'az

2011-01-01

39

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 sl...

Rong, G; Liu, Y; Wang, W; Yin, X; Gu, D; Guo, X

40

Uncertain Centroid based Partitional Clustering of Uncertain Data  

CERN Document Server

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 this work, we theoretically investigate major existing methods of partitional clustering, and alternatively propose a well-founded approach to clustering uncertain data based on a novel notion of cluster centroid. A cluster centroid is seen as an uncertain object defined in terms of a random variable whose realizations are derived based on all deterministic representations of the objects to be clustered. As demonstrated theoretically and experimentally, this allows for better representing a cluster of uncertain objects, thus supporting a co...

Gullo, Francesco

2012-01-01

 
 
 
 
41

A New Derivation of Centroid Defuzzification  

UK PubMed Central (United Kingdom)

We describe a new symmetry-based derivation of centroid defuzzification.The Need for Defuzzification. Fuzzy logic and fuzzy control start with the knowledge expressed byexperts in terms of words from a natural language, and end up with control or decision recommendations;see, e.g., [1, 2, 4].As a result of the standard fuzzy control methodology, we get a fuzzy set (membership function) (u)which describes, for each possible control value u, how reasonable it is to use this particular value. Inautomatic control applications, we want to transform this fuzzy recommendation into a single value u of thecontrol that will actually be applied. This transformation from a fuzzy set to a (non-fuzzy) number is calleda defuzzification.What defuzzification should we apply?The Main Idea Behind the Standard Choice of a Defuzzification. In order to find out whatdefuzzification is the best, let us recall the meaning of the values (u). In fuzzy control, the values (u) areobtained indirect...

Mourad Oussalah

42

Lp Centroidal Voronoi Tesselation and its applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper introduces Lp -Centroidal Voronoi Tessellation (Lp -CVT), a generalization of CVT that minimizes a higher-order moment of the coordinates on the Voronoi cells. This generalization allows for aligning the axes of the Voronoi cells with a predefined background tensor field (anisotropy). Lp ...

Lévy, Bruno; Liu, Yang

43

Maser Source Finding Methods in HOPS  

CERN Multimedia

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

44

A New Derivation of Centroid Defuzzification  

UK PubMed Central (United Kingdom)

We describe a new symmetry-basedderivation of centroid defuzzification.The Need for Defuzzification. Fuzzy logic and fuzzycontrol start with the knowledge expressed by experts interms of words from a natural language, and end up withcontrol or decision recommendations; see, e.g., [1], [2], [4].As a result of the standard fuzzy control methodology,we get a fuzzy set (membership function) (u) which describes,for each possible control value u, how reasonableit is to use this particular value. In automatic controlapplications, we want to transform this fuzzy recommendationinto a single value u of the control that will actuallybe applied. This transformation from a fuzzy set toa (non-fuzzy) number is called a defuzzification.What defuzzification should we apply?The Standard Choice of a Defuzzification is:u =Ru Delta (u) duR(u) du: (1)This formula is called centroid defuzzification, becauseit resembles a formula from mechanics that describes thecenter of m...

Mourad Oussalah; Vladik Kreinovich

45

Centroid neural network for unsupervised competitive learning.  

UK PubMed Central (United Kingdom)

An unsupervised competitive learning algorithm based on the classical -means clustering algorithm is proposed. The proposed learning algorithm called the centroid neural network (CNN) estimates centroids of the related cluster groups in training date. This paper also explains algorithmic relationships among the CNN and some of the conventional unsupervised competitive learning algorithms including Kohonen's self-organizing map (SOM) and Kosko's differential competitive learning (DCL) algorithm. The CNN algorithm requires neither a predetermined schedule for learning coefficient nor a total number of iterations for clustering. The simulation results on clustering problems and image compression problems show that CNN converges much faster than conventional algorithms with compatible clustering quality while other algorithms may give unstable results depending on the initial values of the learning coefficient and the total number of iterations.

Park DC

2000-01-01

46

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

CERN Document Server

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

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

2010-01-01

47

Global Optimization of Centroidal Voronoi Tessellation with Monte Carlo Approach.  

UK PubMed Central (United Kingdom)

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

Lu L; Sun F; Pan H; Wang W

2012-01-01

48

Myopic aberrations: impact of centroiding noise in Hartmann Shack wavefront sensing.  

UK PubMed Central (United Kingdom)

PURPOSE: The presence of photon noise and readout noise can lead to centroiding errors in a Hartmann Shack wavefront sensor (HS) and hence limit the accuracy of wavefront reconstruction. The aim of this paper is to compare, via Monte Carlo simulations, the accuracy of various centroiding methods in detecting noisy focal spot patterns of the HS while sensing ocular aberrations of myopic eyes. METHODS: Myopic ocular aberrations were randomly simulated by using the modal statistics obtained from the measurements of 41 myopic subjects. HS spot patterns were simulated using a fast Fourier method where photon noise and readout noise were added using appropriate statistics. Adopting five different centroiding techniques: (1) centre of gravity, (2) weighted centre of gravity, (3) intensity weighted centroiding, (4) iteratively weighted centre of gravity and (5) matched filter based centroiding along with a zonal based wavefront sensing approach; the wavefronts were estimated and compared, by calculating the root mean square (RMS) wavefront error, with the initially simulated wavefront. The magnitude of readout noise was varied in terms of the maximum number of photons and electrons per subaperture per frame. The RMS error was calculated for each of the centroiding algorithms. RESULTS: For higher magnitude of readout noise and lesser number of photons per subaperture per frame (n), matched filter, iteratively weighted centre of gravity and intensity weighted centroiding outperform centre of gravity and weighted centre of gravity methods, for an appropriately chosen focal length and subaperture pitch. The plots of RMS error as a function of 'n' show that for lower amplitude of readout noise, computationally efficient centre of gravity and intensity weighted centroiding methods can be safely adopted to obtain high enough reconstruction accuracy. Also, even at greater readout noise levels, for a large enough 'n', intensity weighted centroiding is enough to sense the aberrations with high accuracy. It is shown that the wavefront sensing accuracy depends on the size of the spots and bit resolution of the camera. CONCLUSION: Five different centroid detection methods used in a HS in the presence of photon noise and readout noise were analysed in the context of sensing ocular aberrations of myopic subjects and identify cases under which each of these methods is appropriate.

Akondi V; Vohnsen B

2013-07-01

49

Prediction of RNA secondary structure using generalized centroid estimators.  

UK PubMed Central (United Kingdom)

MOTIVATION: Recent studies have shown that the methods for predicting secondary structures of RNAs on the basis of posterior decoding of the base-pairing probabilities has an advantage with respect to prediction accuracy over the conventionally utilized minimum free energy methods. However, there is room for improvement in the objective functions presented in previous studies, which are maximized in the posterior decoding with respect to the accuracy measures for secondary structures. RESULTS: We propose novel estimators which improve the accuracy of secondary structure prediction of RNAs. The proposed estimators maximize an objective function which is the weighted sum of the expected number of the true positives and that of the true negatives of the base pairs. The proposed estimators are also improved versions of the ones used in previous works, namely CONTRAfold for secondary structure prediction from a single RNA sequence and McCaskill-MEA for common secondary structure prediction from multiple alignments of RNA sequences. We clarify the relations between the proposed estimators and the estimators presented in previous works, and theoretically show that the previous estimators include additional unnecessary terms in the evaluation measures with respect to the accuracy. Furthermore, computational experiments confirm the theoretical analysis by indicating improvement in the empirical accuracy. The proposed estimators represent extensions of the centroid estimators proposed in Ding et al. and Carvalho and Lawrence, and are applicable to a wide variety of problems in bioinformatics. AVAILABILITY: Supporting information and the CentroidFold software are available online at: http://www.ncrna.org/software/centroidfold/.

Hamada M; Kiryu H; Sato K; Mituyama T; Asai K

2009-02-01

50

Feature based registration of fluorescent LSCM imagery using region centroids  

Science.gov (United States)

We present a novel semi-automated registration technique for 3D volume reconstruction from fluorescent laser scanning confocal microscope (LSCM) imagery. The developed registration procedure consists of (1) highlighting segmented regions as salient feature candidates, (2) defining two region correspondences by a user, (3) computing a pair of region centroids, as control points for registration, and (4) transforming images according to estimated transformation parameters determined by solving a set of linear equations with input control points. The presented semi-automated method is designed based on our observations that (a) an accurate point selection is much harder for a human than an accurate region (segment) selection, (b) a centroid selection of any region is less accurate by a human than by a computer, and (c) registration based on structural shape of a region rather than on intensity-defined point is more robust to noise and to morphological deformation of features across stacks. We applied the method to image mosaicking and image alignment registration steps and evaluated its performance with 20 human subjects on LSCM images with stained blood vessels. Our experimental evaluation showed significant benefits of automation for 3D volume reconstruction in terms of achieved accuracy, consistency of results and performance time. In addition, the results indicate that the differences between registration accuracy obtained by experts and by novices disappear with an advanced automation while the absolute registration accuracy increases.

Lee, Sang-Chul; Bajcsy, Peter

2005-04-01

51

An Automatic Method of Finding Topic Boundaries  

CERN Multimedia

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 for this work are also outlined.

Reynar, J C

1994-01-01

52

The Schrödinger formulation of the Feynman path centroid density  

CERN Document Server

We present an analysis of the Feynman path centroid density that provides new insight into the correspondence between the path integral and the Schrödinger formulations of statistical mechanics. The path centroid density is a central concept for several approximations (centroid molecular dynamics, quantum transition state theory, and pure quantum self-consistent harmonic approximation) that are used in path integral studies of thermodynamic and dynamical properties of quantum particles. The centroid density is related to the quasi-static response of the equilibrium system to an external force. The path centroid dispersion is the canonical correlation of the position operator, that measures the linear change in the mean position of a quantum particle upon the application of a constant external force. At low temperatures, this quantity provides an approximation to the excitation energy of the quantum system. In the zero temperature limit, the particle's probability density obtained by fixed centroid path integ...

Ramírez, R; Ram\\'irez, Rafael; López-Ciudad, Telesforo

1999-01-01

53

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

54

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

55

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

International Nuclear Information System (INIS)

[en] Purpose: Pixel size is an important parameter of gamma camera and SPECT. A number of Methods are used for its accurate measurement. In the original count-centroid method, where the image of a point source(PS) is acquired and its count-centroid calculated to represent PS position in the image, background counts are inevitable. Thus the measured count-centroid (Xm) is an approximation of the true count-centroid (Xp) of the PS, i.e. Xm=Xp+(Xb-Xp)/(1+Rp/Rb), where Rp is the net counting rate of the PS, Xb the background count-centroid and Rb the background counting rate. To get accurate measurement, Rp must be very big, which is unpractical, resulting in the variation of measured pixel size. Rp-independent calculation of PS count-centroid is desired. Methods: The proposed method attempted to eliminate the effect of the term (Xb-Xp)/(1+Rp/Rb) by bringing Xb closer to Xp and by reducing Rb. In the acquired PS image, a circular ROI was generated to enclose the PS, the pixel with the maximum count being the center of the ROI. To choose the diameter (D) of the ROI, a Gaussian count distribution was assumed for the PS, accordingly, K=I-(0.5)D/R percent of the total PS counts was in the ROI, R being the full width at half maximum of the PS count distribution. D was set to be 6*R to enclose most (K=98.4%) of the PS counts. The count-centroid of the ROI was calculated to represent Xp. The proposed method was tested in measuring the pixel size of a well-tuned SPECT, whose pixel size was estimated to be 3.02 mm according to its mechanical and electronic setting (128*128 matrix, 387 mm UFOV, ZOOM=1). For comparison, the original method, which was use in the former versions of some commercial SPECT software, was also tested. 12 PSs were prepared and their image acquired and stored. The net counting rate of the PSs increased from 10cps to 1183cps. Results: Using the proposed method, the measured pixel size (in mm) varied only between 3.00 and 3.01( mean= 3.01±0.00) as Rp increased, and the difference between the measured and estimated pixel size was

2004-01-01

56

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

CERN Multimedia

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

57

Finding Loop Invariants Based on Wu's Characteristic Set Method  

Directory of Open Access Journals (Sweden)

Full Text Available Loop invariants are important parts in program verification and proof. Correspondingly, techniques for automatically checking and finding invariants have been studied for many years. In present study, an approach using Wu's characteristic set method for automatically finding polynomial invariants of imperative programs is presented. Present method is based on the algebraic theory of polynomial set over polynomial rings, which have wider application domain. We implement this method with the computer algebra tools MMP. The application of the method is demonstrated on a few examples. Compared with other polynomial algebraic approaches, our method is more efficient through experiments.

Yong Cao; Qing-Xin Zhu

2010-01-01

58

Consolidating boundary methods for finding the eigenstates of billiards  

Energy Technology Data Exchange (ETDEWEB)

The plane-wave decomposition method, a widely used means of numerically finding eigenstates of the Helmholtz equation in billiard systems is described as a variant of the mathematically well-established boundary integral method (BIM). A new unified framework encompassing the two methods is discussed. Furthermore, a third numerical method, which we call the gauge freedom method is derived from the BIM equations. This opens the way to further improvements in eigenstate search techniques.

Cohen, Doron [Department of Physics, Ben-Gurion University, Beer-Sheva (Israel); Lepore, Natasha [Department of Physics, Harvard University, Cambridge, MA (United States); Heller, Eric J [Department of Physics, Harvard University, Cambridge, MA (United States)

2004-02-13

59

Consolidating boundary methods for finding the eigenstates of billiards  

International Nuclear Information System (INIS)

[en] The plane-wave decomposition method, a widely used means of numerically finding eigenstates of the Helmholtz equation in billiard systems is described as a variant of the mathematically well-established boundary integral method (BIM). A new unified framework encompassing the two methods is discussed. Furthermore, a third numerical method, which we call the gauge freedom method is derived from the BIM equations. This opens the way to further improvements in eigenstate search techniques

2004-02-13

60

New Methods in Finding Binary Constant Weight Codes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis presents new methods for finding optimal and near-optimal constant weight binary codes with distance d and weight w such that d=2(w-1). These methods have led to the discovery of a number of new codes which are being submitted for publication. Improvements in methods for generating lexic...

Taub, David

 
 
 
 
61

Robust EM continual reassessment method in oncology dose finding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The continual reassessment method (CRM) is a commonly used dose-finding design for phase I clinical trials. Practical applications of this method have been restricted by two limitations: (1) the requirement that the toxicity outcome needs to be observed shortly after the initiation of the treatment;...

Yuan, Y; Yin, G

62

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

63

Plasma Channel Diagnostic Based on Laser Centroid Oscillations  

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-09-09

64

Plasma Channel Diagnostic Based on Laser Centroid Oscillations  

International Nuclear Information System (INIS)

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

2010-01-01

65

Focusing SAR data with time-varying Doppler centroid  

Science.gov (United States)

SAR data spatially sampled at the Nyquist limit can be correctly processed if the Doppler centroid is precisely known. Whenever the Doppler centroid shows rapid variations either with range or azimuth, more care is required in order to take advantage of the computational efficiency of frequency domain techniques. In this paper it is shown that such focusing techniques can still be exploited, provided that SAR raw data are previously modified and a space-varying monodimensional filter is applied to the focused image. The computational cost increases, but it is still smaller than time-space domain processing. Results obtained with simulated SIR-C/X-SAR data and SPOTlight geometries are presented.

Prati, Claudio; Rocca, Fabio

1992-05-01

66

Analysis of optimal centroid estimation applied to Shack Hartmann sensing  

Science.gov (United States)

The problem of estimating the centroid of an incoherently imaged point with a CCD array is analyzed. An exact analysis is presented that uses the actual short-exposure function at the CCD instead of the traditional Gaussian approximation. The analysis shows that, for Poisson noise, the centroid variance depends on the CCD size and that truncation effects play a significant part in determining the optimum CCD size. The effects of this on a wave-front reconstruction formed by a Shack Hartmann sensor are described.

Irwan, Roy; Lane, Richard. G.

1999-11-01

67

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

68

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

International Nuclear Information System (INIS)

[en] 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

2009-01-01

69

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

1998-01-01

70

Resolution enhancement of Doppler frequency measurements using a centroid technique  

Energy Technology Data Exchange (ETDEWEB)

A centroid-based technique for locating peaks in the frequency spectrum is demonstrated to have the potential for substantially enhancing the resolution of Fourier-based laser Doppler velocimetry measurements. The effect of data windowing and signal-to-noise ratio on the potential resolution improvement is also analyzed. (orig.)

Naguib, A. [Mechanical Engineering, Michigan State University East Lansing, MI (United States)

2002-05-01

71

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

72

Computed tomographic methods and findings in adenomyomatosis of the gallbladder  

International Nuclear Information System (INIS)

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

2002-01-01

73

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

International Nuclear Information System (INIS)

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

2004-01-01

74

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

International Nuclear Information System (INIS)

[en] 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, applied to a nine heated tube bundle experimental data set. (Author)

1986-01-01

75

A Method to Find Community Structures Based on Information Centrality  

CERN Multimedia

Community structures are an important feature of many social, biological and technological networks. Here we propose a new method for detecting such communities based on the idea proposed by Girvan and Newman of using centrality measures to define the community boundaries. We develop an algorithm of hierarchical clustering that consists in finding and removing iteratively the edge with the highest information centrality. We test the algorithm on computer generated and real-world networks whose community structure is already known or has been studied by means of other methods. We show that our algorithm, although not fast, is very effective especially when the communities are very mixed and hardly detectable by the other methods.

Fortunato, S; Marchiori, M; Fortunato, Santo; Latora, Vito; Marchiori, Massimo

2004-01-01

76

A method for finding three-dimensional magnetic skeletons  

International Nuclear Information System (INIS)

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

2010-01-01

77

A Simple Method To Find All Lensed Quasars  

CERN Multimedia

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 curves and colors. This will allow planned large-scale synoptic surveys to find lensed quasars almost down to their detection limits without the need for extensive follow-up observations.

Kochanek, C S; Morgan, N D; Stanek, K Z

2006-01-01

78

Energy centroids in transfer reactions on complex target states  

International Nuclear Information System (INIS)

Using a mixed-configuration and multishell codes, the partial shell occupancies of target states in nickel isotopes have been calculated and then applied the Bansal sum rules to obtain values for the centroids of residual nuclei with mass= A + 1, where A is the target mass number. These calculations are limited to targets having only neutron shell active, the protons forming a closed shell. (author).

1976-12-31

79

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

CERN Multimedia

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

Jang, Seogjoo

2013-01-01

80

Robust EM Continual Reassessment Method in Oncology Dose Finding.  

Science.gov (United States)

The continual reassessment method (CRM) is a commonly used dose-finding design for phase I clinical trials. Practical applications of this method have been restricted by two limitations: (1) the requirement that the toxicity outcome needs to be observed shortly after the initiation of the treatment; and (2) the potential sensitivity to the prespecified toxicity probability at each dose. To overcome these limitations, we naturally treat the unobserved toxicity outcomes as missing data, and use the expectation-maximization (EM) algorithm to estimate the dose toxicity probabilities based on the incomplete data to direct dose assignment. To enhance the robustness of the design, we propose prespecifying multiple sets of toxicity probabilities, each set corresponding to an individual CRM model. We carry out these multiple CRMs in parallel, across which model selection and model averaging procedures are used to make more robust inference. We evaluate the operating characteristics of the proposed robust EM-CRM designs through simulation studies and show that the proposed methods satisfactorily resolve both limitations of the CRM. Besides improving the MTD selection percentage, the new designs dramatically shorten the duration of the trial, and are robust to the prespecification of the toxicity probabilities. PMID:22375092

Yuan, Ying; Yin, Guosheng

2011-09-01

 
 
 
 
81

Robust EM Continual Reassessment Method in Oncology Dose Finding.  

UK PubMed Central (United Kingdom)

The continual reassessment method (CRM) is a commonly used dose-finding design for phase I clinical trials. Practical applications of this method have been restricted by two limitations: (1) the requirement that the toxicity outcome needs to be observed shortly after the initiation of the treatment; and (2) the potential sensitivity to the prespecified toxicity probability at each dose. To overcome these limitations, we naturally treat the unobserved toxicity outcomes as missing data, and use the expectation-maximization (EM) algorithm to estimate the dose toxicity probabilities based on the incomplete data to direct dose assignment. To enhance the robustness of the design, we propose prespecifying multiple sets of toxicity probabilities, each set corresponding to an individual CRM model. We carry out these multiple CRMs in parallel, across which model selection and model averaging procedures are used to make more robust inference. We evaluate the operating characteristics of the proposed robust EM-CRM designs through simulation studies and show that the proposed methods satisfactorily resolve both limitations of the CRM. Besides improving the MTD selection percentage, the new designs dramatically shorten the duration of the trial, and are robust to the prespecification of the toxicity probabilities.

Yuan Y; Yin G

2011-09-01

82

A method to find palindromes in nucleic acid sequences  

Science.gov (United States)

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

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

2013-01-01

83

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

2013-01-01

84

Model Independent Analysis of Beam Centroid Dynamics in Accelerators  

International Nuclear Information System (INIS)

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

2003-01-01

85

Evolutionary method for finding communities in bipartite networks.  

UK PubMed Central (United Kingdom)

An important step in unveiling the relation between network structure and dynamics defined on networks is to detect communities, and numerous methods have been developed separately to identify community structure in different classes of networks, such as unipartite networks, bipartite networks, and directed networks. Here, we show that the finding of communities in such networks can be unified in a general framework-detection of community structure in bipartite networks. Moreover, we propose an evolutionary method for efficiently identifying communities in bipartite networks. To this end, we show that both unipartite and directed networks can be represented as bipartite networks, and their modularity is completely consistent with that for bipartite networks, the detection of modular structure on which can be reformulated as modularity maximization. To optimize the bipartite modularity, we develop a modified adaptive genetic algorithm (MAGA), which is shown to be especially efficient for community structure detection. The high efficiency of the MAGA is based on the following three improvements we make. First, we introduce a different measure for the informativeness of a locus instead of the standard deviation, which can exactly determine which loci mutate. This measure is the bias between the distribution of a locus over the current population and the uniform distribution of the locus, i.e., the Kullback-Leibler divergence between them. Second, we develop a reassignment technique for differentiating the informative state a locus has attained from the random state in the initial phase. Third, we present a modified mutation rule which by incorporating related operations can guarantee the convergence of the MAGA to the global optimum and can speed up the convergence process. Experimental results show that the MAGA outperforms existing methods in terms of modularity for both bipartite and unipartite networks.

Zhan W; Zhang Z; Guan J; Zhou S

2011-06-01

86

Contact lens assessment in youth: methods and baseline findings.  

UK PubMed Central (United Kingdom)

PURPOSE: To describe the Contact Lens Assessment in Youth (CLAY) Study design and report baseline data for a multicenter, retrospective, observational chart review of children, teenagers, and young adult soft contact lens (SCL) wearers. METHODS: Clinical charts of SCL wearers aged 8 to 33 years were reviewed at six colleges of optometry. Data were captured retrospectively for eye care visits from January 2006 through September 2009. Patient demographics, SCL parameters, wearing schedules, care systems, and biomicroscopy findings and complications that interrupted SCL wear were entered into an online database. RESULTS: Charts from 3549 patients (14,276 visits) were reviewed; 78.8% were current SCL wearers and 21.2% were new fits. Age distribution was 8 to <13 years (n = 260, 7.3%), 13 to <18 years (n = 879, 24.8%), 18 to <26 years (n = 1,274, 36.0%), and 26 to <34 years (n = 1,136, 32.0%). The sample was 63.2% females and 37.7% college students. At baseline, 85.2% wore spherical SCLs, 13.5% torics, and 0.1% multifocals. Silicone hydrogel lenses were worn by 39.3% of the cohort. Daily wear was reported by 82.1%, whereas 17.9% reported any or occasional overnight wear. Multipurpose care systems were used by 78.1%, whereas another 9.9% indicated hydrogen peroxide solutions use. CONCLUSIONS: This data represent the SCL prescribing and wearing patterns for children, teenager, and young adult SCL wearers who presented for eye care in North American academic clinics. This will provide insight into SCL utilization, change in SCL refractive correction, and risk factors for SCL-related complications by age group.

Lam DY; Kinoshita BT; Jansen ME; Mitchell GL; Chalmers RL; McMahon TT; Richdale K; Sorbara L; Wagner H

2011-06-01

87

Combined centroid-envelope dynamics of intense, magnetically focused charged beams surrounded by conducting walls  

International Nuclear Information System (INIS)

In this paper we analyze the combined envelope-centroid dynamics of magnetically focused high-intensity charged beams surrounded by conducting walls. Similar to the case where conducting walls are absent, it is shown that the envelope and centroid dynamics decouple from each other. Mismatched envelopes still decay into equilibrium with simultaneous emittance growth, but the centroid keeps oscillating with no appreciable energy loss. Some estimates are performed to analytically obtain characteristics of halo formation seen in the full simulations.

2006-01-01

88

Methods to find out the expression of activated genes  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract This review deals with the methods of identifying genes that have been activated by inner or outer impulses. The activation and subsequent expression of a gene can be detected by its transcription into a corresponding messenger ribonucleic acid (mRNA). Principles of the methods for identification of individual activated genes, as well as groups of activated genes are described, the former methods being mostly based on subtractive hybridization and serial analysis of gene expression (SAGE), the latter on microarrays. Examples of gene activation by the hormone 17beta-estradiol (E2) are given.

Cekan Sten Z

2004-01-01

89

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

90

Generalized method for finding community structures in networks  

CERN Multimedia

To date, most algorithms aiming to find community structures in networks mainly focus on unipartite or bipartite networks. However, to our knowledge, there is no algorithm specifically designed for the mixture network, a third type defined in our paper that represents a wide range of real-world networks. Interestingly, unipartite and bipartite networks can be viewed as limiting cases of a mixture network, suggesting that the mixture network can be considered as a general condition. Based on this observation, we propose a probabilistic model based on the link community model for a unipartite, undirected network [B. Ball, B. Karrer, and M. E. Newman, Phys. Rev. E 84, 036103 (2011)] by redefining this model in the context of a bipartite network and generalizing the bipartite network version model to a mixture network, the general condition, which can be used to find modules in unipartite, bipartite, and mixture networks in a unified framework. We show that both the model of Ball et al. (unipartite, undirected ne...

Chang, Chang

2013-01-01

91

Finding function: evaluation methods for functional genomic data  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Accurate evaluation of the quality of genomic or proteomic data and computational methods is vital to our ability to use them for formulating novel biological hypotheses and directing further experiments. There is currently no standard approach to evaluation in functional genomics. Our analysis of existing approaches shows that they are inconsistent and contain substantial functional biases that render the resulting evaluations misleading both quantitatively and qualitatively. These problems make it essentially impossible to compare computational methods or large-scale experimental datasets and also result in conclusions that generalize poorly in most biological applications. Results We reveal issues with current evaluation methods here and suggest new approaches to evaluation that facilitate accurate and representative characterization of genomic methods and data. Specifically, we describe a functional genomics gold standard based on curation by expert biologists and demonstrate its use as an effective means of evaluation of genomic approaches. Our evaluation framework and gold standard are freely available to the community through our website. Conclusion Proper methods for evaluating genomic data and computational approaches will determine how much we, as a community, are able to learn from the wealth of available data. We propose one possible solution to this problem here but emphasize that this topic warrants broader community discussion.

Myers Chad L; Barrett Daniel R; Hibbs Matthew A; Huttenhower Curtis; Troyanskaya Olga G

2006-01-01

92

Time delay and magnification centroid due to gravitational lensing by black holes and naked singularities  

CERN Multimedia

We model the massive dark object at the center of the Galaxy as a Schwarzschild black hole as well as Janis-Newman-Winicour naked singularities, characterized by the mass and scalar charge parameters, and study gravitational lensing (particularly time delay, magnification centroid, and total magnification) by them. We find that the lensing features are qualitatively similar (though quantitatively different) for the Schwarzschild black holes, weakly naked, and marginally strongly naked singularities. However, the lensing characteristics of strongly naked singularities are qualitatively very different from those due the Schwarzschild black holes. The images produced by Schwarzschild black hole lenses and weakly naked and marginally strongly naked singularity lenses always have positive time delays. On the other hand, the strongly naked singularity lenses can give rise to images with positive, zero, or negative time delays. In particular, for a large angular source position the direct image (the outermost image ...

Virbhadra, K S

2007-01-01

93

METHOD FOR FINDING GENETIC MARKERS OF SOMACLONAL VARIATION  

UK PubMed Central (United Kingdom)

The invention provides a method for obtaining molecular markers for use as a diagnostic and quality control tool to identify genomic polymorphisms that arise during the process of tissue culture of i(in vitro) propagated plants. By using a representational difference analysis (RDA) adapted for plant genomes, a set of nucleic acid difference sequences between normal and off-type plant genomes are obtained. The invention further provides a method for isolating sets of variant sequences which are common to many naturally occurring or tissue culture-generated off-types of the same cultivar or species, in addition to variant sequences present in all off-types, regardless of the phenotypic mutation, and/or in all off-types that exhibit the same mutation. Detection of somaclonal variation by the method of the invention may present an opportunity to optimize tissue culture conditions and to optimize plant multiplication rates without producing a significant number of off-types.

CULLIS Christopher A.; RADEMAN Samantha; KUNERT Karl

94

Finding the Stationary States of Markov Chains by Iterative Methods  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, we develop new methods for approximating dominant eigenvector of column-stochastic matrices. We analyze the Google matrix, and present an averaging scheme with linear rate of convergence in terms of 1-norm distance. For extending this convergence result onto general case, we assume ex...

Nesterov, Yurii; Nemirovski, Arkadi

95

Research on Language Learning Strategies: Methods, Findings, and Instructional Issues.  

Science.gov (United States)

Surveys research on formal and informal second-language learning strategies, covering the effectiveness of research methods involving making lists, interviews and thinking aloud, note-taking, diaries, surveys, and training. Suggestions for future and improved research are presented. (131 references) (CB)

Oxford, Rebecca; Crookall, David

1989-01-01

96

Variational method for finding periodic orbits in a general flow  

CERN Document Server

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

97

Variational method for finding periodic orbits in a general flow.  

UK PubMed Central (United Kingdom)

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.

Lan Y; Cvitanovi? P

2004-01-01

98

Finding Similarities in Ancient Ceramics by EDXRF and Multivariate Methods  

International Nuclear Information System (INIS)

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

1999-01-01

99

Estimation Normal Vector of Triangular Mesh Vertex by Angle and Centroid Weights and its Application  

Digital Repository Infrastructure Vision for European Research (DRIVER)

To compute vertex normal of triangular meshes more accurately, this paper presents an improved algorithm based on angle and centroid weights. Firstly, four representational algorithms are analyzed by comparing their weighting characteristics such as angles, areas and centroids. The drawbacks of e...

Yueping Chen; Jian Gao; Hao Wen; Xin Chen

100

Improvement of structure conservation index with centroid estimators.  

UK PubMed Central (United Kingdom)

RNAz, a support vector machine (SVM) approach for identifying functional non-coding RNAs (ncRNAs), has been proven to be one of the most accurate tools for this goal. Among the measurements used in RNAz, the Structure Conservation Index (SCI) which evaluates the evolutionary conservation of RNA secondary structures in terms of folding energies, has been reported to have an extremely high discrimination capability. However, for practical use of RNAz on the genome-wide search, a relatively high false discovery rate has unfortunately been estimated. It is conceivable that multiple alignments produced by a standard aligner that does not consider any secondary structures are not suitable for identifying ncRNAs in some cases and incur high false discovery rate. In this study, we propose C-SCI, an improved measurement based on the SCI applying gamma-centroid estimators to incorporate the robustness against low quality multiple alignments. Our experiments show that the C-SCI achieves higher accuracy than the original SCI for not only human-curated structural alignments but also low quality alignments produced by CLUSTAL W. Furthermore, the accuracy of the C-SCI on CLUSTAL W alignments is comparable with that of the original SCI on structural alignments generated with RAF for which 4.7-fold expensive computational time is required on average.

Okada Y; Sato K; Sakakibara Y

2010-01-01

 
 
 
 
101

Improvement of structure conservation index with centroid estimators.  

Science.gov (United States)

RNAz, a support vector machine (SVM) approach for identifying functional non-coding RNAs (ncRNAs), has been proven to be one of the most accurate tools for this goal. Among the measurements used in RNAz, the Structure Conservation Index (SCI) which evaluates the evolutionary conservation of RNA secondary structures in terms of folding energies, has been reported to have an extremely high discrimination capability. However, for practical use of RNAz on the genome-wide search, a relatively high false discovery rate has unfortunately been estimated. It is conceivable that multiple alignments produced by a standard aligner that does not consider any secondary structures are not suitable for identifying ncRNAs in some cases and incur high false discovery rate. In this study, we propose C-SCI, an improved measurement based on the SCI applying gamma-centroid estimators to incorporate the robustness against low quality multiple alignments. Our experiments show that the C-SCI achieves higher accuracy than the original SCI for not only human-curated structural alignments but also low quality alignments produced by CLUSTAL W. Furthermore, the accuracy of the C-SCI on CLUSTAL W alignments is comparable with that of the original SCI on structural alignments generated with RAF for which 4.7-fold expensive computational time is required on average. PMID:19908361

Okada, Yohei; Sato, Kengo; Sakakibara, Yasubumi

2010-01-01

102

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

103

On the calculation of single-particle time correlation functions from Bose-Einstein centroid dynamics.  

UK PubMed Central (United Kingdom)

The calculation of single-particle time correlation functions using the Bose-Einstein centroid dynamics formalism is discussed. A new definition of the quasidensity operator is used to calculate the centroid force on a given particle for an anharmonic system. The force includes correlation effects due to quantum statistics and is used for the calculation of the classical-like dynamics of phase-space centroid variables within the centroid molecular dynamics approximation. Time correlation functions are then obtained for single-particle quantities. These correspond to the double-Kubo transform of exact quantum-mechanical correlation functions. The centroid dynamics results are compared to those of exact basis-set calculations and a good agreement is found. The level of accuracy is in fact the same as what was observed earlier for the calculation of center-of-mass correlation functions for Fermi-Dirac and Bose-Einstein statistics, and for any correlation function for Boltzmann statistics. These results show that it is now possible to use Bose-Einstein centroid molecular dynamics to calculate single-particle correlation functions for systems where quantum exchange effects are present.

Moffatt P; Blinov N; Roy PN

2004-03-01

104

An Efficient Range Partitioning Method for Finding Frequent Patterns from Huge Database  

Directory of Open Access Journals (Sweden)

Full Text Available Data mining is finding increasing acceptance inscience and business areas that need to analyzelarge amounts of data to discover trends that theycould not otherwise find. Different applications mayrequire different data mining techniques. The kindsof knowledge that could be discovered from adatabase are categorized into association rulesmining, sequential patterns mining, classification,and clustering. In this paper we present an efficientrange partitioning method for finding frequentpattern from huge database. It is based on key baseddivision for finding the local frequent pattern(LFP). After finding the partition frequent patternfrom the subdivided local database, we then find theglobal frequent pattern from the local database andperform the pruning from the whole database.

Ms. Ruchita Gupta; Dr.C.S.Satsangi

2012-01-01

105

Time delay and magnification centroid due to gravitational lensing by black holes and naked singularities  

International Nuclear Information System (INIS)

We model the massive dark object at the center of the Galaxy as a Schwarzschild black hole as well as Janis-Newman-Winicour naked singularities, characterized by the mass and scalar charge parameters, and study gravitational lensing (particularly time delay, magnification centroid, and total magnification) by them. We find that the lensing features are qualitatively similar (though quantitatively different) for Schwarzschild black holes, weakly naked, and marginally strongly naked singularities. However, the lensing characteristics of strongly naked singularities are qualitatively very different from those due to Schwarzschild black holes. The images produced by Schwarzschild black hole lenses and weakly naked and marginally strongly naked singularity lenses always have positive time delays. On the other hand, strongly naked singularity lenses can give rise to images with positive, zero, or negative time delays. In particular, for a large angular source position the direct image (the outermost image on the same side as the source) due to strongly naked singularity lensing always has a negative time delay. We also found that the scalar field decreases the time delay and increases the total magnification of images; this result could have important implications for cosmology. As the Janis-Newman-Winicour metric also describes the exterior gravitational field of a scalar star, naked singularities as well as scalar star lenses, if these exist in nature, will serve as more efficient cosmic telescopes than regular gravitational lenses.

2008-06-15

106

Enhancement of proteinase inhibitory activity of recombinant human cystatin C using random-centroid optimization.  

UK PubMed Central (United Kingdom)

We had previously written a random-centroid optimization computer program for genetics (RCG) to optimize protein engineering, which was successfully applied to modify single site of the 16 amino acid residues at the active site of B. stearothermophilys neutral protease for improving thermostability [J. Agric. Food Chem., 46 (1998) 1655]. The same program was applied in this study to double-site mutation of the entire sequence of human cystatin C (HCC) with 120 residues for improving its protease inhibitory activity. The RCG program selected two sites simultaneously and amino acid residues to replace the sites selected in the sequence in order to find the best papain-inhibitory activity and stability of the protease inhibitor. Twenty-three double mutants and twenty-two single mutants were expressed by Pichia pastoris. Of the total 45 mutants, G12W/H86V mutant showed a 5-fold increase in the bioactivity over the recombinant wild-type (WT) cystatin. Also, P13F mutant exhibited a half-life temperature (T1/2) 5.2 degrees C higher than 68.2 degrees C of WT in addition to a 56% greater papain inhibitory activity. Mutation for diminishing beta-sheet content reduced polymerization of cystatin C, thus improving papain-inhibitory activity. The approach using RCG was able to improve the functional properties of cystatin by least relying on the prior knowledge of its molecular structure.

Ogawa M; Nakamura S; Scaman CH; Jing H; Kitts DD; Dou J; Nakai S

2002-09-01

107

Centroid based clustering of high throughput sequencing reads based on n-mer counts.  

UK PubMed Central (United Kingdom)

BACKGROUND: Many problems in computational biology require alignment-free sequence comparisons. One of thecommon tasks involving sequence comparison is sequence clustering. Here we apply methods ofalignment-free comparison (in particular, comparison using sequence composition) to the challengeof sequence clustering. RESULTS: We study several centroid based algorithms for clustering sequences based on word counts. Study oftheir performance shows that using k-means algorithm with or without the data whitening is efficientfrom the computational point of view. A higher clustering accuracy can be achieved using the softexpectation maximization method, whereby each sequence is attributed to each cluster with a specificprobability. We implement an open source tool for alignment-free clustering. It is publicly availablefrom github: https://github.com/luscinius/afcluster. CONCLUSIONS: We show the utility of alignment-free sequence clustering for high throughput sequencing analysisdespite its limitations. In particular, it allows one to perform assembly with reduced resources and aminimal loss of quality. The major factor affecting performance of alignment-free read clustering isthe length of the read.

Solovyov A; Lipkin WI

2013-09-01

108

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

Energy Technology Data Exchange (ETDEWEB)

The optical components of the Swift Gamma Ray Burst Explorer X-ray Telescope (XRT), consisting of the JET-X spare flight mirror and a charge coupled device of the type used in the EPIC program, were used in a re-calibration study carried out at the Panter facility, which is part of the Max Plank Institute for Extraterrestrial Physics. The objective of this study was to check the focal length and the off axis performance of the mirrors and to show that the half energy width (HEW) of the on-axis point spread function (PSF) was of the order of 16 arcsec at 1.5 keV (Nucl. Instr. and Meth. A 488 (2002) 543; SPIE 4140 (2000) 64) and that a centroiding accuracy better that 1 arcsec could be achieved within the 4 arcmin sampling area designated by the Burst Alert Telescope (Nucl. Instr. and Meth. A 488 (2002) 543). The centroiding accuracy of the Swift XRT's optical components was tested as a function of distance from the focus and off axis position of the PSF (Nucl. Instr. and Meth. A 488 (2002) 543). The presence of background events in the image frame introduced errors in the centroiding process, making the choice of centroiding algorithm important (Nucl. Instr. and Meth. A 488 (2002) 543). Since the objective of Swift is to rapidly investigate the X-ray afterglows of Gamma Ray Bursts the possibility of detecting a bright source with intensity greater than 25 Crab could not be excluded and therefore the impact of a saturated PSF core on the centroiding accuracy was investigated by experimental methods.

Ambrosi, R.M. E-mail: rma@star.le.ac.uk; Hutchinson, I.B.; Hill, J.; Cheruvu, C.; Abbey, A.F.; Short, A.D.T

2002-11-01

109

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

DEFF Research Database (Denmark)

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

Watt, Dominic; Fabricius, Anne

2011-01-01

110

Ranked centroid projection: a data visualization approach with self-organizing maps.  

UK PubMed Central (United Kingdom)

The self-organizing map (SOM) is an efficient tool for visualizing high-dimensional data. In this paper, the clustering and visualization capabilities of the SOM, especially in the analysis of textual data, i.e., document collections, are reviewed and further developed. A novel clustering and visualization approach based on the SOM is proposed for the task of text mining. The proposed approach first transforms the document space into a multidimensional vector space by means of document encoding. Afterwards, a growing hierarchical SOM (GHSOM) is trained and used as a baseline structure to automatically produce maps with various levels of detail. Following the GHSOM training, the new projection method, namely the ranked centroid projection (RCP), is applied to project the input vectors to a hierarchy of 2-D output maps. The RCP is used as a data analysis tool as well as a direct interface to the data. In a set of simulations, the proposed approach is applied to an illustrative data set and two real-world scientific document collections to demonstrate its applicability.

Yen GG; Wu Z

2008-02-01

111

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

UK PubMed Central (United Kingdom)

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

Faisal TR; Hristozov N; Rey AD; Western TL; Pasini D

2012-09-01

112

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

Science.gov (United States)

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

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

2012-09-01

113

Finding-equal regression method and its application in predication of U resources  

International Nuclear Information System (INIS)

The commonly adopted deposit model method in mineral resources predication has two main part: one is model data that show up geological mineralization law for deposit, the other is statistics predication method that accords with characters of the data namely pretty regression method. This kind of regression method may be called finding-equal regression, which is made of the linear regression and distribution finding-equal method. Because distribution finding-equal method is a data pretreatment which accords with advanced mathematical precondition for the linear regression namely equal distribution theory, and this kind of data pretreatment is possible of realization. Therefore finding-equal regression not only can overcome nonlinear limitations, that are commonly occurred in traditional linear regression or other regression and always have no solution, but also can distinguish outliers and eliminate its weak influence, which would usually appeared when Robust regression possesses outlier in independent variables. Thus this newly finding-equal regression stands the best status in all kind of regression methods. Finally, two good examples of U resource quantitative predication are provided

1995-01-01

114

Quantum Imaging beyond the Diffraction Limit by Centroid Measurements  

CERN Multimedia

I propose a quantum imaging method that can beat the Rayleigh-Abbe diffraction limit and achieve de Broglie resolution without requiring a multiphoton absorber as the detector. Using the same non-classical states of light as those for quantum lithography, the proposed method requires only intensity measurements, followed by image post-processing, to produce the same complex image patterns as those in quantum lithography. The method is expected to be experimentally realizable using current technology.

Tsang, Mankei

2009-01-01

115

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

International Nuclear Information System (INIS)

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

2005-01-01

116

Analysis of optimal centroid estimation applied to Shack-Hartmann sensing.  

UK PubMed Central (United Kingdom)

The problem of estimating the centroid of an incoherently imaged point with a CCD array is analyzed. An exact analysis is presented that uses the actual short-exposure function at the CCD instead of the traditional Gaussian approximation. The analysis shows that, for Poisson noise, the centroid variance depends on the CCD size and that truncation effects play a significant part in determining the optimum CCD size. The effects of this on a wave-front reconstruction formed by a Shack-Hartmann sensor are described.

Irwan R; Lane RG

1999-11-01

117

Analysis of optimal centroid estimation applied to Shack-Hartmann sensing.  

Science.gov (United States)

The problem of estimating the centroid of an incoherently imaged point with a CCD array is analyzed. An exact analysis is presented that uses the actual short-exposure function at the CCD instead of the traditional Gaussian approximation. The analysis shows that, for Poisson noise, the centroid variance depends on the CCD size and that truncation effects play a significant part in determining the optimum CCD size. The effects of this on a wave-front reconstruction formed by a Shack-Hartmann sensor are described. PMID:18324213

Irwan, R; Lane, R G

1999-11-10

118

On the Reversibility of Newton-Raphson Root-Finding Method  

Energy Technology Data Exchange (ETDEWEB)

Reversibility of a computational method is the ability to execute the method forward as well as backward. Reversible computational methods are generally useful in undoing incorrect computation in a speculative execution setting designed for efficient parallel processing. Here, reversibility is explored of a common component in scientific codes, namely, the Newton-Raphson root-finding method. A reverse method is proposed that is aimed at retracing the sequence of points that are visited by the forward method during forward iterations. When given the root, along with the number of iterations, of the forward method, this reverse method is aimed at backtracking along the reverse sequence of points to finally recover the original starting point of the forward method. The operation of this reverse method is illustrated on a few example functions, serving to highlight the method's strengths and shortcomings.

Perumalla, Kalyan S [ORNL; Wright, John P [ORNL; Kuruganti, Phani Teja [ORNL

2008-07-01

119

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.

120

Unified framework for finding eigenstates of Helmholtz equation using boundary methods  

CERN Document Server

The powerful plane-wave decomposition method (PWDM) for finding eigenstates of Helmholtz equation can be regarded as a variant of the mathematically well-established boundary integral method (BIM). The capabilities of the BIM and the PWDM are discussed using a unified framework. This opens the way to further improvements.

Cohen, D; Heller, E J; Cohen, Doron; Lepore, Natasha; Heller, Eric J.

2001-01-01

 
 
 
 
121

ALIGNMENT APPARATUS FOR ALIGNING DYNAMIC CENTROID OF LOWER LIMB PROSTHESIS  

UK PubMed Central (United Kingdom)

A drive unit for the central alignment of the artificial leg is provided, which is able to find dynamic center and makes the center alignment process facilitated. A drive unit for the central alignment of the artificial leg comprises: a frame(100) an inclination drive unit(110) which is installed at the upper part of the frame and makes a stump operate to the right and left slantingly and a front and back inclining drive unit(120) in which a rotation plate is installed to be fixed and the stump is selectively fixed to the driving shaft to operate the stump backward and forward.

SEON DONG YUN

122

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

CERN Document Server

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 verify our method.

Wan, Li

2011-01-01

123

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

124

Level set methods for finding critical points of mountain pass type  

CERN Multimedia

Computing mountain passes is a standard way of finding critical points. We describe a numerical method for finding critical points that is convergent in the nonsmooth case and locally superlinearly convergent in the smooth finite dimensional case. We apply these techniques to describe a strategy for the Wilkinson problem of calculating the distance of a matrix to a closest matrix with repeated eigenvalues. Finally, we relate critical points of mountain pass type to nonsmooth and metric critical point theory.

Lewis, Adrian S

2009-01-01

125

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

2010-01-01

126

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 includ...

Xia Wu; Xiong Yu; Hao Jing

127

Centroid-based summarization of multiple documents sentence extraction, utility-based evaluation and user studies  

CERN Multimedia

We present a multi-document summarizer, called MEAD, which generates summaries using cluster centroids produced by a topic detection and tracking system. We also describe two new techniques, based on sentence utility and subsumption, which we have applied to the evaluation of both single and multiple document summaries. Finally, we describe two user studies that test our models of multi-document summarization.

Radev, D R; Budzikowska, M; Radev, Dragomir R.; Jing, Hongyan; Budzikowska, Malgorzata

2000-01-01

128

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

129

A hybrid method for the exact planted (l, d) motif finding problem and its parallelization.  

UK PubMed Central (United Kingdom)

BACKGROUND: Given a set of DNA sequences s1, ..., st, the (l, d) motif problem is to find an l-length motif sequence M , not necessary existing in any of the input sequences, such that for each sequence si, 1 ? i ? t, there is at least one subsequence differing with at most d mismatches from M. Many exact algorithms have been developed to solve the motif finding problem in the last three decades. However, the problem is still challenging and its solution is limited to small values of l and d. RESULTS: In this paper we present a new efficient method to improve the performance of the exact algorithms for the motif finding problem. Our method is composed of two main steps: First, we process q ? t sequences to find candidate motifs. Second, the candidate motifs are searched in the remaining sequences. For both steps, we use the best available algorithms. Our method is a hybrid one, because it integrates currently existing algorithms to achieve the best running time. In this paper, we show how the optimal value of q is determined to achieve the best running time. Our experimental results show that there is about 24% speed-up achieved by our method compared to the best existing algorithm. Furthermore, we also present a parallel version of our method running on shared memory architecture. Our experiments show that the performance of our algorithm scales linearly with the number of processors. Using the parallel version, we were able to solve the (21, 8) challenging instance using 8 processors in 20.42 hours instead of 6.68 days of the serial version. CONCLUSIONS: Our method speeds up the solution of the exact motif problem. Our method is generic, because it can accommodate any new faster algorithm based on traditional methods. We expect that our method will help to discover longer motifs. The software we developed is available for free for academic research at http://www.nubios.nileu.edu.eg/tools/hymotif.

Abbas MM; Abouelhoda M; Bahig HM

2012-01-01

130

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

131

Methods for synthesizing findings on moderation effects across multiple randomized trials.  

UK PubMed Central (United Kingdom)

This paper presents new methods for synthesizing results from subgroup and moderation analyses across different randomized trials. We demonstrate that such a synthesis generally results in additional power to detect significant moderation findings above what one would find in a single trial. Three general methods for conducting synthesis analyses are discussed, with two methods, integrative data analysis and parallel analyses, sharing a large advantage over traditional methods available in meta-analysis. We present a broad class of analytic models to examine moderation effects across trials that can be used to assess their overall effect and explain sources of heterogeneity, and present ways to disentangle differences across trials due to individual differences, contextual level differences, intervention, and trial design.

Brown CH; Sloboda Z; Faggiano F; Teasdale B; Keller F; Burkhart G; Vigna-Taglianti F; Howe G; Masyn K; Wang W; Muthén B; Stephens P; Grey S; Perrino T

2013-04-01

132

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

CERN Multimedia

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

Censor, Yair; Reich, Simeon

2012-01-01

133

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

Energy Technology Data Exchange (ETDEWEB)

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

Lee, M.J.; Clearwater, S.H.; Kleban, S.D.; Selig, L.J.

1987-02-01

134

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

International Nuclear Information System (INIS)

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

1987-01-01

135

Genetically Informative Research on Adolescent Substance Use: Methods, Findings, and Challenges  

Science.gov (United States)

Objective: To provide an overview of the genetic epidemiology of substance use and misuse in adolescents. Method: A selective review of genetically informative research strategies, their limitations, and key findings examining issues related to the heritability of substance use and substance use disorders in children and adolescents is presented.…

Lynskey, Michael T.; Agrawal, Arpana; Heath, Andrew C.

2010-01-01

136

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

International Nuclear Information System (INIS)

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

2005-01-01

137

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.

1990-01-01

138

Method to find the electron distribution function from cylindrical probe data  

International Nuclear Information System (INIS)

Druyvesteyn's method finds the distribution of electron speeds from the second derivative of probe data using the assumption that the distribution is spherically symmetric. For the disk probe, the data are more directly related to the velocity distribution projected onto the direction normal to the probe surface. The projected distribution is less sensitive to noise because it is related to the first derivative of the data rather than the second. For the cylindrical probe, the data are more directly related to the distribution of energies projected onto the plane perpendicular to the probe axis. A method is developed for recovering this projected distribution from digitized probe data. The method is mathematically more complex than Druyvesteyn's method, but has the advantage of being less sensitive to noise. The methods are compared using noise-free simulated data and using noisy data from a double-plasma device with multidipolar magnetic confinement.

2006-01-01

139

A method for finding single-nucleotide polymorphisms with allele frequencies in sequences of deep coverage  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The allele frequencies of single-nucleotide polymorphisms (SNPs) are needed to select an optimal subset of common SNPs for use in association studies. Sequence-based methods for finding SNPs with allele frequencies may need to handle thousands of sequences from the same genome location (sequences of deep coverage). Results We describe a computational method for finding common SNPs with allele frequencies in single-pass sequences of deep coverage. The method enhances a widely used program named PolyBayes in several aspects. We present results from our method and PolyBayes on eighteen data sets of human expressed sequence tags (ESTs) with deep coverage. The results indicate that our method used almost all single-pass sequences in computation of the allele frequencies of SNPs. Conclusion The new method is able to handle single-pass sequences of deep coverage efficiently. Our work shows that it is possible to analyze sequences of deep coverage by using pairwise alignments of the sequences with the finished genome sequence, instead of multiple sequence alignments.

Wang Jianmin; Huang Xiaoqiu

2005-01-01

140

A numerical study of bunched beam transverse e-p instability based on the centroid model  

Energy Technology Data Exchange (ETDEWEB)

In a recent theoretical study of the transverse electron-proton (e-p) instability, an asymptotic solution has been found for the equations describing the centroid motion of the traversing proton bunch and the stationary background electrons. It was shown that the combination of finite proton bunch length, non-uniform proton line density, and the single-pass e-p interaction cause the instability to evolve intricately in space and time even in the linear regime. This paper reports a numerical study of the e-p instability based on the same centroid equations. The purpose of the work is to compare the numerical solution with the analytic solution and to use the numerical approach to investigate the early development of the instability not covered by the asymptotic solution. In particular, the instability threshold and the initial growth of the instability are studied for various proton-beam conditions, fraction of charge neutralization, and initial perturbations.

Wang, T. F. (Tai-Sen F.)

2003-01-01

 
 
 
 
141

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

Science.gov (United States)

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

Yonemoto, Haruka; Asai, Kiyoshi; Hamada, Michiaki

2013-01-01

142

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

Directory of Open Access Journals (Sweden)

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

Haruka Yonemoto; Kiyoshi Asai; Michiaki Hamada

2013-01-01

143

Experimental evaluation of centroiding algorithms at different light intensity and noise levels  

Science.gov (United States)

In this paper, we present results from an experimental evaluation of centroiding algorithms, simple center of gravity (CoG) and weighted center of gravity (WCoG) in a Shack Hartmann wavefront sensor at different light levels and background noise conditions. CoG performs better than WCoG at good light conditions. WCoG performs better than CoG algorithm at low light level conditions and in cases of high intensity.

Roopashree, M. B.; Vyas, Akondi; Prasad, B. Raghavendra

2011-10-01

144

Tuberculosis Case Finding: Evaluation of a Paper Slip Method to Trace Contacts  

Science.gov (United States)

Setting South Africa has the third highest tuberculosis (TB) burden in the world. Intensified case finding, recommended by WHO, is one way to control TB. Objective To evaluate the effectiveness and acceptability of a paper slip method for TB contact tracing. Method TB patients were offered paper slips to give to their contacts, inviting them for TB screening. The number of contacts screened and the proportion diagnosed with TB was calculated. Contacts that returned to the clinic after receiving the slips were interviewed. A focus group discussion (FGD) with TB patients was held to determine their acceptability. Results From 718 paper slips issued, a 26% TB contact tracing rate was found, with a 12% case detection rate. The majority (68%) of contacts were screened within 2 weeks of receiving the slip. Age and gender were not significantly associated with time to screening. 16% of the contacts screened did not reside with the TB patients. 98% of the contacts said the method was acceptable. FGD findings show that this method is acceptable and may prevent stigma associated with TB/HIV. Conclusion This simple, inexpensive method yields high contact tracing and case detection rates and potentially would yield additional benefits outside households.

Mwansa-Kambafwile, Judith; McCarthy, Kerrigan; Gharbaharan, Varanna; Venter, Francois W. D.; Maitshotlo, Boitumelo; Black, Andrew

2013-01-01

145

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; V. Ricny; M. Slanina

2013-01-01

146

A compilation of jet finding algorithms  

Energy Technology Data Exchange (ETDEWEB)

Technical descriptions of jet finding algorithms currently in use in p{anti p} collider experiments (CDF, UA1, UA2), e{sup +}e{sup {minus}} experiments and Monte-Carlo event generators (LUND programs, ISAJET) have been collected. For the hadron collider experiments, the clustering methods fall into two categories: cone algorithms and nearest-neighbor algorithms. In addition, UA2 has employed a combination of both methods for some analysis. While there are clearly differences between the cone and nearest-neighbor algorithms, the authors have found that there are also differences among the cone algorithms in the details of how the centroid of a cone cluster is located and how the E{sub T} and P{sub T} of the jet are defined. The most commonly used jet algorithm in electron-positron experiments is the JADE-type cluster algorithm. Five various incarnations of this approach have been described.

Flaugher, B. [Fermilab, Batavia, IL (United States); Meier, K. [DESY, Hamburg (Germany)

1992-12-31

147

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-04-28

148

Fractional dose-finding methods with late-onset toxicity in phase I clinical trials.  

UK PubMed Central (United Kingdom)

In Phase I clinical trials, the algorithm-based dose-finding methods, such as the 3 + 3 and up-and-down designs, do not impose any dose-toxicity curve. In contrast, model-based designs, such as the continual reassessment method (CRM), assume a parametric model to borrow information from all the doses under consideration. For these conventional dose-finding methods, toxicity outcomes need to be observed shortly after the treatment, so that newly enrolled patients can be treated without delay. However, in the case of late-onset toxicity, patients' outcomes may not be observed quickly enough to keep up with the speed of enrollment, and thus toxicity data may not be available when that information is needed. Patients who have not experienced toxicity by the decision-making time may yet experience toxicity later during the rest of the follow-up. Ignoring such late-onset toxicity information may lead to biased estimation of the dose toxicity probabilities and thus compromise the trial's performance. To expand the applicability of the 3 + 3, up-and-down, and CRM designs with late-onset toxicity, we propose to redistribute the mass of the censored observation to the right and utilize the fractional contribution for the unobserved toxicity outcome. We evaluate the operating characteristics of the proposed fractional designs through extensive simulation studies. The fractional designs satisfactorily resolve the issues associated with late-onset toxicity, and are compared favorably with other available methods.

Yin G; Zheng S; Xu J

2013-01-01

149

Methods and findings of a systems interaction study of a Westinghouse PWR  

International Nuclear Information System (INIS)

This paper describes the methods and findings of a systems interaction study of a Westinghouse PWR. BNL conducted the study as a methods application that was performed to support the resolution of Unresolved Safety Issue A-17 on Systems Interactions. The method calls for a fault tree model of the plant to be developed in stages, corresponding to successively increasing levels of scope and detail. A functional model is developed first, resolved only to sufficient detail to reflect support system dependences; this guides the subsequent searches for spatial and induced-human interactions. This process has led to the identification of an active single failure causing loss of low pressure injection following a large or medium LOCA.

1985-03-01

150

A group-theory method to find stationary states in nonlinear discrete symmetry systems  

Science.gov (United States)

In the field of nonlinear optics, the self-consistency method has been applied to searching optical solitons in different media. In this paper, we generalize this method to other systems, adapting it to discrete symmetry systems by using group theory arguments. The result is a new technique that incorporates symmetry concepts into the iterative procedure of the self-consistency method, that helps the search of symmetric stationary solutions. An efficient implementation of this technique is also presented, which restricts the computational work to a reduced section of the entire domain and is able to find different types of solutions by specifying their symmetry properties. As a practical application, we develop an efficient algorithm for solving the nonlinear Schrödinger equation with a discrete symmetry potential.

Zacarés, M.; Arevalillo-Herráez, M.; Abraham, S.

2010-01-01

151

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

International Nuclear Information System (INIS)

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

2003-03-31

152

Numerical method for finding decoherence-free subspaces and its applications  

Science.gov (United States)

In this work, inspired by the study of semidefinite programming for block-diagonalizing matrix *-algebras, we propose an algorithm that can find the algebraic structure of decoherence-free subspaces (DFS's) for a given noisy quantum channel. We prove that this algorithm will work for all cases with probability 1, and it is more efficient than the algorithm proposed by J. A. Holbrook, D. W. Kribs, and R. Laflamme, [Quantum. Inf. Proc.1570-075510.1023/B:QINP.0000022737.53723.b4 80, 381 (2003)]. In fact, our results reveal that this previous algorithm only works for special cases. As an application, we discuss how this method can be applied to increase the efficiency of an optimization procedure for finding an approximate DFS.

Wang, Xiaoting; Byrd, Mark; Jacobs, Kurt

2013-01-01

153

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

Science.gov (United States)

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

Song, Yun S; Steinrücken, Matthias

2011-12-29

154

Using a Euclid distance discriminant method to find protein coding genes in the yeast genome.  

UK PubMed Central (United Kingdom)

The Euclid distance discriminant method is used to find protein coding genes in the yeast genome, based on the single nucleotide frequencies at three codon positions in the ORFs. The method is extremely simple and may be extended to find genes in prokaryotic genomes or eukaryotic genomes with less introns. Six-fold cross-validation tests have demonstrated that the accuracy of the algorithm is better than 93%. Based on this, it is found that the total number of protein coding genes in the yeast genome is less than or equal to 5579 only, about 3.8-7.0% less than 5800-6000, which is currently widely accepted. The base compositions at three codon positions are analyzed in details using a graphic method. The result shows that the preference codons adopted by yeast genes are of the RGW type, where R, G and W indicate the bases of purine, non-G and A/T, whereas the 'codons' in the intergenic sequences are of the form NNN, where N denotes any base. This fact constitutes the basis of the algorithm to distinguish between coding and non-coding ORFs in the yeast genome. The names of putative non-coding ORFs are listed here in detail.

Zhang CT; Wang J; Zhang R

2002-02-01

155

A method for finding the ridge between saddle points applied to rare event rate estimates.  

UK PubMed Central (United Kingdom)

A method is presented for finding the ridge between first order saddle points on a multidimensional surface. For atomic scale systems, such saddle points on the energy surface correspond to atomic rearrangement mechanisms. Information about the ridge can be used to test the validity of the harmonic approximation to transition state theory, in particular to verify that second order saddle points--maxima along the ridge--are high enough compared to the first order saddle points. New minima along the ridge can also be identified during the path optimisation, thereby revealing additional transition mechanisms. The method is based on a string of discretisation points along a path between the first order saddle points and using an iterative optimisation which requires only the force acting on the atoms. At each iteration during the optimisation, the force is inverted along an unstable eigenmode perpendicular to the path. The method is applied to Al adatom diffusion on the Al(100) surface to find the ridge between 2-, 3- and 4-atom concerted displacements and hop mechanisms. A correction to the harmonic approximation of transition state theory was estimated by direct evaluation of the configuration integral along the ridge.

Maronsson JB; Jónsson H; Vegge T

2012-02-01

156

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

UK PubMed Central (United Kingdom)

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

Song YS; Steinrücken M

2012-03-01

157

A method for finding the ridge between saddle points applied to rare event rate estimates  

DEFF Research Database (Denmark)

A method is presented for finding the ridge between first order saddle points on a multidimensional surface. For atomic scale systems, such saddle points on the energy surface correspond to atomic rearrangement mechanisms. Information about the ridge can be used to test the validity of the harmonic approximation to transition state theory, in particular to verify that second order saddle points—maxima along the ridge—are high enough compared to the first order saddle points. New minima along the ridge can also be identified during the path optimisation, thereby revealing additional transition mechanisms. The method is based on a string of discretisation points along a path between the first order saddle points and using an iterative optimisation which requires only the force acting on the atoms. At each iteration during the optimisation, the force is inverted along an unstable eigenmode perpendicular to the path. The method is applied to Al adatom diffusion on the Al(100) surface to find the ridge between 2-,3- and 4-atom concerted displacements and hop mechanisms. A correction to the harmonic approximation of transition state theory was estimated by direct evaluation of the configuration integral along the ridge.

Maronsson, Jon Bergmann; Jónsson, Hannes

2012-01-01

158

A Pattern Matching method for finding Noun and Proper Noun Translations from Noisy Parallel Corpora  

CERN Multimedia

We present a pattern matching method for compiling a bilingual lexicon of nouns and proper nouns from unaligned, noisy parallel texts of Asian/Indo-European language pairs. Tagging information of one language is used. Word frequency and position information for high and low frequency words are represented in two different vector forms for pattern matching. New anchor point finding and noise elimination techniques are introduced. We obtained a 73.1\\% precision. We also show how the results can be used in the compilation of domain-specific noun phrases.

Fung, P

1995-01-01

159

Efficient method of finding scaling exponents from finite-size Monte-Carlo simulations  

CERN Multimedia

Monte-Carlo simulations are routinely used for estimating the scaling exponents of complex systems. However, due to finite-size effects, determining the exponent values is often difficult and not reliable. Here we present a novel technique of dealing with the problem of finite-size scaling. This new method allows not only to decrease the uncertainties of the scaling exponents, but makes it also possible to determine the exponents of the asymptotic corrections to the scaling laws. The efficiency of the technique is demonstrated by finding the scaling exponent of uncorrelated percolation cluster hulls.

Mandre, Indrek; 10.1140/epjb/e2012-30954-7

2013-01-01

160

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

 
 
 
 
161

DISCO-SCA and properly applied GSVD as swinging methods to find common and distinctive processes.  

UK PubMed Central (United Kingdom)

BACKGROUND: In systems biology it is common to obtain for the same set of biological entities information from multiple sources. Examples include expression data for the same set of orthologous genes screened in different organisms and data on the same set of culture samples obtained with different high-throughput techniques. A major challenge is to find the important biological processes underlying the data and to disentangle therein processes common to all data sources and processes distinctive for a specific source. Recently, two promising simultaneous data integration methods have been proposed to attain this goal, namely generalized singular value decomposition (GSVD) and simultaneous component analysis with rotation to common and distinctive components (DISCO-SCA). RESULTS: Both theoretical analyses and applications to biologically relevant data show that: (1) straightforward applications of GSVD yield unsatisfactory results, (2) DISCO-SCA performs well, (3) provided proper pre-processing and algorithmic adaptations, GSVD reaches a performance level similar to that of DISCO-SCA, and (4) DISCO-SCA is directly generalizable to more than two data sources. The biological relevance of DISCO-SCA is illustrated with two applications. First, in a setting of comparative genomics, it is shown that DISCO-SCA recovers a common theme of cell cycle progression and a yeast-specific response to pheromones. The biological annotation was obtained by applying Gene Set Enrichment Analysis in an appropriate way. Second, in an application of DISCO-SCA to metabolomics data for Escherichia coli obtained with two different chemical analysis platforms, it is illustrated that the metabolites involved in some of the biological processes underlying the data are detected by one of the two platforms only; therefore, platforms for microbial metabolomics should be tailored to the biological question. CONCLUSIONS: Both DISCO-SCA and properly applied GSVD are promising integrative methods for finding common and distinctive processes in multisource data. Open source code for both methods is provided.

Van Deun K; Van Mechelen I; Thorrez L; Schouteden M; De Moor B; van der Werf MJ; De Lathauwer L; Smilde AK; Kiers HA

2012-01-01

162

Mapping shape quantitative trait loci using a radius-centroid-contour model.  

UK PubMed Central (United Kingdom)

As the consequence of complex interactions between different parts of an organ, shape can be used as a predictor of structural-functional relationships implicated in changing environments. Despite such importance, however, it is no surprise that little is known about the genetic detail involved in shape variation, because no approach is currently available for mapping quantitative trait loci (QTLs) that control shape. Here, we address this problem by developing a statistical model that integrates the principle of shape analysis into a mixture-model-based likelihood formulated for QTL mapping. One state-of-the-art approach for shape analysis is to identify and analyze the polar coordinates of anatomical landmarks on a shape measured in terms of radii from the centroid to the contour at regular intervals. A procrustes analysis is used to align shapes to filter out position, scale and rotation effects on shape variation. To the end, the accurate and quantitative representation of a shape is produced with aligned radius-centroid-contour (RCC) curves, that is, a function of radial angle at the centroid. The high dimensionality of the RCC data, crucial for a comprehensive description of the geometric feature of a shape, is reduced by principal component (PC) analysis, and the resulting PC axes are treated as phenotypic traits, allowing specific QTLs for global and local shape variability to be mapped, respectively. The usefulness and utilization of the new model for shape mapping in practice are validated by analyzing a mapping data collected from a natural population of poplar, Populus szechuanica var tibetica, and identifying several QTLs for leaf shape in this species. The model provides a powerful tool to compute which genes determine biological shape in plants, animals and humans.

Fu G; Bo W; Pang X; Wang Z; Chen L; Song Y; Zhang Z; Li J; Wu R

2013-06-01

163

An operator method for finding exact solutions to vector Korteweg-de Vries equations  

Science.gov (United States)

We develop an operator method which helps finding exact solutions to nonlinear evolution equations (NLEs). Our working schema goes as follows: First we translate the given (NLE) into an appropriate operator version (ONLE). Second, we look for solutions to (ONLE) of the form U=(I+L)-1M, where both L and M are operator-valued functions of the space-time variables and the range of M locates in some appropriate Banach algebras which admits a functional ? that preserves the squares [i.e., ?(A2)=?(A)2]. Finally, a solution u of the given (NLE) can be obtained by setting u??(U). This method is named by the LM method. Using the LM method, we have rederived the famous Cole-Hopf transformation which reduces the nonlinear Burgers equation into the linear heat equation. The main part of this article is to use the LM method to study the vector Korteweg-de Vries (KdV) equations ut=uxxx+3(u2)x settled in finite-dimensional unital Banach algebras J. It is shown that these vector KdV equations admit soliton solutions. Specially, we have carried out a thorough study of the quaternionic KdV equation (i.e., the vector KdV equation settled in the Hamilton quaternion algebra H) and shown many interesting and surprising aspects of the quaternionic KdV solitons. Two of them read as follows. (a) The paradoxical energy symmetry breaking phenomenon: Two quaternionic KdV solitons with different energies can annihilate each other. (b) The surprising low-dimensional phenomenon: The interaction of any finitely many quaternionic KdV solitons which live in a unital three-dimensional subspace ? of H does not yield any effect to the part outside that subspace ? and thus their interaction behaves as if it were linear although the interaction between quaternionic KdV solitons is really nonlinear. The LM method can be thought as a complement to the famous bilinear operator method of Hirota. Hirota's method works very powerful for solving scalar equation but has difficulty with vector equations. The LM method helps overcoming this difficulty.

Huang, Sen-Zhong

2003-03-01

164

GeneWaltz--A new method for reducing the false positives of gene finding.  

UK PubMed Central (United Kingdom)

BACKGROUND: Identifying protein-coding regions in genomic sequences is an essential step in genome analysis. It is well known that the proportion of false positives among genes predicted by current methods is high, especially when the exons are short. These false positives are problematic because they waste time and resources of experimental studies. METHODS: We developed GeneWaltz, a new filtering method that reduces the risk of false positives in gene finding. GeneWaltz utilizes a codon-to-codon substitution matrix that was constructed by comparing protein-coding regions from orthologous gene pairs between mouse and human genomes. Using this matrix, a scoring scheme was developed; it assigned higher scores to coding regions and lower scores to non-coding regions. The regions with high scores were considered candidate coding regions. One-dimensional Karlin-Altschul statistics was used to test the significance of the coding regions identified by GeneWaltz. RESULTS: The proportion of false positives among genes predicted by GENSCAN and Twinscan were high, especially when the exons were short. GeneWaltz significantly reduced the ratio of false positives to all positives predicted by GENSCAN and Twinscan, especially when the exons were short. CONCLUSIONS: GeneWaltz will be helpful in experimental genomic studies. GeneWaltz binaries and the matrix are available online at http://en.sourceforge.jp/projects/genewaltz/.

Misawa K; Kikuno RF

2010-01-01

165

A MODIFIED ALGORITHM FOR THRESHOLDING AND DETECTION OF FACIAL INFORMATION FROM COLOR IMAGES USING COLOR CENTROID SEGMENTATION AND CONTOURLET TRANSFORM  

Directory of Open Access Journals (Sweden)

Full Text Available Human face detection plays an important role in many application areas such as video surveillance, human computer interface, face recognition, face search and face image database management etc. In human face detection applications, face region usually form an inconsequential part of images. Preliminary segmentation of images into regions that contain "non-face" objects and regions that may contain "face" can greatly accelerate the process of human face detection. This can be done using skin color segmentation, where given image is segmented based on color as 'skin region' and 'non skin regions'. Thus we can say that the skin regions may contain face and other regions don't. Color information based methods take a great attention, because colors have obviously character and robust visual cue for detection. This paper proposes a method based on RGB color centroids segmentation (CCS) for face detection. This paper includes two parts, first part is color image thresholding based on CCS to perform skin color segmentation and the then detection of human face from detected skin regions. CCS method has some shortcomings as it fails when the skin color of the subject lacks chroma. This happens especially with subjects having too darker or too lighter skin tones. This shortcoming of CCS can be overcome using Contourlet Transformation. In this paper, we pursue a two dimensional transform that can capture the intrinsic geometrical structure that is key in visual information.

Sunish Kumar O S; Akash G Kamal

2011-01-01

166

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

CERN Multimedia

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

167

Super-resolution imaging reveals a difference between SERS and luminescence centroids.  

UK PubMed Central (United Kingdom)

Super-resolution optical imaging of Rhodamine 6G surface-enhanced Raman scattering (SERS) and silver luminescence from colloidal silver aggregates are measured with sub-5 nm resolution and found to originate from distinct spatial locations on the nanoparticle surface. Using correlated scanning electron microscopy, the spatial origins of the two signals are mapped onto the nanoparticle structure, revealing that, while both types of emission are plasmon-mediated, SERS is a highly local effect, probing only a single junction in a nanoparticle aggregate, whereas luminescence probes all collective plasmon modes within the nanostructure. Calculations using the discrete-dipole approximation to calculate the weighted centroid position of both the |E|(2)/|E(inc)|(2) and |E|(4)/|E(inc)|(4) electromagnetic fields were compared to the super-resolution centroid positions of the SERS and luminescence data and found to agree with the proposed plasmon dependence of the two emission signals. These results are significant to the field of SERS because they allow us to assign the exact nanoparticle junction responsible for single-molecule SERS emission in higher order aggregates and also provide insight into how SERS is coupled into the plasmon modes of the underlying nanostructure, which is important for developing new theoretical models to describe SERS emission.

Weber ML; Litz JP; Masiello DJ; Willets KA

2012-02-01

168

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

169

A novel method for finding non-small cell lung cancer diagnosis biomarkers.  

UK PubMed Central (United Kingdom)

BACKGROUND: One of the most common causes of worldwide cancer premature death is non-small cell lung carcinoma (NSCLC) with a very low survival rate of 8%-15%. Since patients with an early stage diagnosis can have up to four times the survival rate, discovering cost-effective biological markers that can be used to improve the diagnosis and prognosis of the disease is an important clinical challenge.In the last few years, significant progress has been made to address this challenge with identified biomarkers ranging from 5-gene signatures to 133-gene signatures. However, A typical molecular sub-classification method for lung carcinomas would have a low predictive accuracy of 68%-71% because datasets of gene-expression profiles typically have tens of thousands of genes for just few hundreds of patients. This type of datasets create many technical challenges impacting the accuracy of the diagnostic prediction. RESULTS: We discovered that a small set of nine gene-signatures (JAG1, MET, CDH5, ABCC3, DSP, ABCD3, PECAM1, MAPRE2 and PDF5) from the dataset of 12,600 gene-expression profiles of NSCLC acts like an inference basis for NSCLC lung carcinoma and hence can be used as genetic markers. This very small and previously unknown set of biological markers gives an almost perfect predictive accuracy (99.75%) for the diagnosis of the disease the sub-type of cancer. Furthermore, we present a novel method that finds genetic markers for sub-classification of NSCLC. We use generalized Lorenz curves and Gini ratios to overcome many challenges arose from datasets of gene-expression profiles. Our method discovers novel genetic changes that occur in lung tumors using gene-expression profiles. CONCLUSIONS: While proteins encoded by some of these gene-signatures (e.g., JAG1 and MAPRE2) have been showed to involve in the signal transduction of cells and proliferation control of normal cells, specific functions of proteins encoded by other gene-signatures have not yet been determined. Hence, this work opens new questions for structural and molecular biologists about the role of these gene-signatures for the disease.

Tran QN

2013-01-01

170

Cross-Lingual Information Retrieval Problems: Methods and findings for three language pairs  

UK PubMed Central (United Kingdom)

In this paper we will discss dictionary-baWxcross-la ngage informaion retrieval (CLIR) methods, a dreport recent findings a nd problems. We will consider three la ngage paq9q for CLIR: Finnish to English,English to Finnish, Swedish to English. We show tha t Finnish a nd Swedish ha ve specia l feat res, e.g., thefreq ency of homograO6a nd ahigh freq ency of compo nd words thaaffect retrieva effectiveness.Especia)y correct word formnormaliza ion a d compo ndsplitting are essentia,O We report findingsconcerning the effectiveness ofvario s q erytra nslation methods, q ery str ctres and ling istic toolssed for CLIR. We aso point ot some problems and deficiencies in s ch tools.1. Introdu tionThere is an increaing amo nt of fll text materia9 in vaq) s laq aes a vailaq;q throgh the Internet andother informa,q n s ppliers. ThereforeCross-la ngageinformationretrieval (CLIR)hasbecome animportat new resea,xarea (OaWq & Dorr, 1996; Pirkola, 1999). It is a process of selecting d raz ingdoc ments in a,z,) a e different from the qery la ngage. One of the man aq;z9)Fes to CLIR is ba edon bilinga l tra nsla tion dictiona ries. For a n overview of the aFqW6z)es, see (H ll & Greffenstette, 1996;Oa rd & Dorr, 1996; Pirkola, 1999).The main problemssociaxq) with dictionary-b a ed CLIR aqW (1) phra eidentificaO9; and traslation,(2) so rcela nga ge ambig ity, (3)tra nsla tion ambig ity, (4) thecoverage ofdictionaries, (5) theprocessing of inflected words, d (6) ntraxla table keys, in paq ic laqproper names spelled differentlyin different la, a es. Translation ambiguity refers to the proportion l incre se of b d keys due totr nsl tion. Rese rch h s developed m ny effective methods to...

Turid Hedlund; Heikki Keskusta; Lervo Jrvelin

171

A novel method for finding non-small cell lung cancer diagnosis biomarkers  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background One of the most common causes of worldwide cancer premature death is non-small cell lung carcinoma (NSCLC) with a very low survival rate of 8%-15%. Since patients with an early stage diagnosis can have up to four times the survival rate, discovering cost-effective biological markers that can be used to improve the diagnosis and prognosis of the disease is an important clinical challenge. In the last few years, significant progress has been made to address this challenge with identified biomarkers ranging from 5-gene signatures to 133-gene signatures. However, A typical molecular sub-classification method for lung carcinomas would have a low predictive accuracy of 68%-71% because datasets of gene-expression profiles typically have tens of thousands of genes for just few hundreds of patients. This type of datasets create many technical challenges impacting the accuracy of the diagnostic prediction. Results We discovered that a small set of nine gene-signatures (JAG1, MET, CDH5, ABCC3, DSP, ABCD3, PECAM1, MAPRE2 and PDF5) from the dataset of 12,600 gene-expression profiles of NSCLC acts like an inference basis for NSCLC lung carcinoma and hence can be used as genetic markers. This very small and previously unknown set of biological markers gives an almost perfect predictive accuracy (99.75%) for the diagnosis of the disease the sub-type of cancer. Furthermore, we present a novel method that finds genetic markers for sub-classification of NSCLC. We use generalized Lorenz curves and Gini ratios to overcome many challenges arose from datasets of gene-expression profiles. Our method discovers novel genetic changes that occur in lung tumors using gene-expression profiles. Conclusions While proteins encoded by some of these gene-signatures (e.g., JAG1 and MAPRE2) have been showed to involve in the signal transduction of cells and proliferation control of normal cells, specific functions of proteins encoded by other gene-signatures have not yet been determined. Hence, this work opens new questions for structural and molecular biologists about the role of these gene-signatures for the disease.

Tran Quoc-Nam

2013-01-01

172

Reconciling incongruous qualitative and quantitative findings in mixed methods research: exemplars from research with drug using populations.  

UK PubMed Central (United Kingdom)

Mixed methods research is increasingly being promoted in the health sciences as a way to gain more comprehensive understandings of how social processes and individual behaviours shape human health. Mixed methods research most commonly combines qualitative and quantitative data collection and analysis strategies. Often, integrating findings from multiple methods is assumed to confirm or validate the findings from one method with the findings from another, seeking convergence or agreement between methods. Cases in which findings from different methods are congruous are generally thought of as ideal, whilst conflicting findings may, at first glance, appear problematic. However, the latter situation provides the opportunity for a process through which apparently discordant results are reconciled, potentially leading to new emergent understandings of complex social phenomena. This paper presents three case studies drawn from the authors' research on HIV risk amongst injection drug users in which mixed methods studies yielded apparently discrepant results. We use these case studies (involving injection drug users [IDUs] using a Needle/Syringe Exchange Program in Los Angeles, CA, USA; IDUs seeking to purchase needle/syringes at pharmacies in Tijuana, Mexico; and young street-based IDUs in San Francisco, CA, USA) to identify challenges associated with integrating findings from mixed methods projects, summarize lessons learned, and make recommendations for how to more successfully anticipate and manage the integration of findings. Despite the challenges inherent in reconciling apparently conflicting findings from qualitative and quantitative approaches, in keeping with others who have argued in favour of integrating mixed methods findings, we contend that such an undertaking has the potential to yield benefits that emerge only through the struggle to reconcile discrepant results and may provide a sum that is greater than the individual qualitative and quantitative parts.

Wagner KD; Davidson PJ; Pollini RA; Strathdee SA; Washburn R; Palinkas LA

2012-01-01

173

Qualitative findings from a mixed methods evaluation of once-weekly therapeutic community day services for people with personality disorder.  

UK PubMed Central (United Kingdom)

BACKGROUND: This paper presents qualitative findings from a mixed methods study of four one-day-a-week therapeutic communities (TCs) in the north of England for people with personality disorder. Quantitative findings from the study are presented separately. AIMS: The study aimed to ascertain whether one-day-a-week TCs can be effective in addressing the problems associated with personality disorder. METHOD: The qualitative component of the study comprised semi-structured interviews with service users, service user consultants, staff and referrers. This paper reports findings from the interviews with service users. FINDINGS: The qualitative findings indicate underlying changes in thinking that may account for some of the measurable changes in members' mental health and functioning reported in the quantitative findings. In particular, the services enable individuals to address two main problem areas: relating to others and self-harm. CONCLUSIONS: The study suggests that once-weekly TCs provide an effective therapeutic approach to the problems associated with personality disorder.

Hodge S; Barr W; Göpfert M; Hellin K; Horne A; Kirkcaldy A

2010-02-01

174

Mental states of adolescents exposed to war in Uganda: finding appropriate methods of rehabilitation.  

UK PubMed Central (United Kingdom)

BACKGROUND: Reintegration after war brings with it enormous challenges. One such challenge is to find appropriate methods of rehabilitation during the reintegration process. This article describes the rehabilitation, using traditional therapy, of formerly abducted adolescents exposed to war events who have experienced psychological distress. METHODOLOGY: In a cross-sectional design, 294 adolescents aged 12 to19 at three rehabilitation centres participated in the study. Two checklists specifically designed for the study were administered to the adolescents and social workers: the War Experiences Checklist and Psychological State Checklist. The War Experiences Checklist includes 54 different war events broadly categorised under nine themes: separation, role in combat, deprivations, rituals in captivity, injury and being a victim of violence, witness to traumatic war events, laying landmines and staging ambushes, participation in violence, and sexual abuse. The Psychological State Checklist consists of 22 items. Structured interviews were used with centre coordinators and traditional leaders to elicit information on strategies of rehabilitation and traditional therapies of rehabilitation respectively. Descriptive statistics were used to analyse data from the checklists while data from the interviews were triangulated and subjected to thematic examination in a multistage analyses. RESULTS: Adolescents were exposed to disquieting war events and participated in dreadful atrocities. Consequently, many were psychologically distressed with unhealthy mental states that needed cleansing according to the native Acholi traditional practices of reconciliation and reintegration. Four rituals used in the rehabilitation and reintegration are critically examined in this paper. CONCLUSION: Although mired in controversy over legitimacy, scope, and disagreement over procedures, the traditional structures for reconciliation and reintegration, such as the cleansing rituals, are still widely recognised and can play an important role in the process of reintegration at the local level.

Amone-P'Olak K

2006-01-01

175

Shack-Hartmann wavefront sensing with elongated sodium laser beacons: centroiding versus matched filtering.  

UK PubMed Central (United Kingdom)

We describe modeling and simulation results for the Thirty Meter Telescope on the degradation of sodium laser guide star Shack-Hartmann wavefront sensor measurement accuracy that will occur due to the spatial structure and temporal variations of the mesospheric sodium layer. By using a contiguous set of lidar measurements of the sodium profile, the performance of a standard centroid and of a more refined noise-optimal matched filter spot position estimation algorithm is analyzed and compared for a nominal mean signal level equal to 1000 photodetected electrons per subaperture per integration time, as a function of subaperture to laser launch telescope distance and CCD pixel readout noise. Both algorithms are compared in terms of their rms spot position estimation error due to noise, their associated wavefront error when implemented on the Thirty Meter Telescope facility adaptive optics system, their linear dynamic range, and their bias when detuned from the current sodium profile.

Gilles L; Ellerbroek B

2006-09-01

176

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-10-01

177

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; AmirMasoud Rahmani; MohammadReza EffatParvar; Mehdi Dehghan

2011-01-01

178

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

179

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

180

Determination of coordinates of seismic observation points by the method of sound direction finding  

Energy Technology Data Exchange (ETDEWEB)

An examination is made of the theoretical and experimental aspects of the technique for automatic determination of the observation point coordinates using sound direction finding and multichannel systems for collection and processing of the seismic information. Multichannel placement of the seismic receivers is irradiated by a sound impulse from several sources arranged on a field, and by recording the time for arrival of the sound waves and the known sound velocity in air, the coordinates are computed for all the seismic receivers on the field. Experimental work indicated the high accuracy and reliability of isolating the sound signals by their amplitude and frequency parameters.

Yeliseyev, B.A.; Mashinskiy, E.I.; Saprykin, S.N.; Vedernikov, G.V.

1984-01-01

 
 
 
 
181

Thermal analysis of parabolic concentrator for finding optical efficiency by different methods with varying parameters.  

Directory of Open Access Journals (Sweden)

Full Text Available Parabolic concentrator is used to utilize the solar energy for heating purpose. Thermal tests are performed on concentrator at different time periods and at different masses to find the variation in the optical efficiency and heat loss factor. The results verified by graphical test can be used to design the concentrator for the desired output. It was found that the system gave almost the same values of optical efficiency, for the various masses of water on different days. The value of optical efficiency factor increases slightly by reducing the mass of water. The value of optical efficiency for the parabolic concentrator is obtained as 35%.

Abhijeet Auti; Dr. T. P. Singh; Dr. Dilip R. Pangavhane

2013-01-01

182

The Exploration of the Artistic Methods and Significances of Cartoonised Characters of A Good Man Is Hard to Find  

Directory of Open Access Journals (Sweden)

Full Text Available Flannery O’Connor is one of the 20th Century Southern American writers, whose usual theme of absurdity and alienation is well embodied in her classic short story A Good Man Is Hard to Find. This paper mainly deals with the cartoonised characters, especially the granny. The artistic methods used to describe the characters are closely related to the following: realistic method, exaggerative method, metaphorical method, and symbolic method. This article attempts to explore the artistic methods used to describe the characters and their significances and also their contributions to the theme of absurdity and alienation. Key words: A Good Man Is Hard to Find, cartoonised character, absurdity Résumé Flannery O’Connor est une des femmes écrivains très connues des Etats-Unis du IIe siècle. Son recueil des nouvelles « A Good Man Is Hard to Find » attire surtout plus d’attention des lecteurs. Il décris des personnages humouristiques très vives, ce qui se traduit en évidence par la grand-mère. Les méthodes de description des personnages caricaturistes( les méthodes artistiques) peuvent de résumer en : méthodes réalistique, méthode exagérative, méthode métaphorique et méthode symbolique. Cette thèse part des personnages humoristiques et cherche les formes de description et les significations des personnages dans des oeuves pour dévoiler le thème d’absurdité. Mots-clés: A Good Man Is Hard to Find, les personnages humoristiques, l’absurdité. ? ? ???? •???? 20???????????????????????????????????????????????????????????????????????????????????????? (????)???????????????????????????????????????????????????????????????????????????????????

Ke-ke ZHANG

2005-01-01

183

Finding the Social Value of Forests Through Stated Preference Methods: A Mediterranean Forest Valuation Exercise  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A declaração de preferências corresponde ao método mais comum para estimar o valor social das florestas ou dos seus atributos. Este artigo ilustra o uso deste método para estimar o valor de algumas funções recreativas das florestas mediterrâneas, assim como do sequestro de CO2 e da prevenção da erosão do solo. Analisa também os resultados de aproximações de ordenação contingente no âmbito de métodos que envolvem a declaração de preferências. Abstract in english There are several methods to estimate the social value of forests or forest attributes, the most widely used being the stated preference methods. This paper illustrates the use of such methods to estimate some recreational functions of Mediterranean forests, as well as CO2 sequestration and soil erosion prevention. It also compares the results from a contingent ranking and a choice experiment method application.

Riera, Pere; Mogas, Joan

2004-06-01

184

Finding capability of ash content of coal by electronic paramagnetic-resonance method  

International Nuclear Information System (INIS)

[en] In this article author investigated capability of ash content of coal by electronic paramagnetic-resonance method. Numerical attribute of substances for electronic paramagnetic-resonance method found on those, what of area at curved of resonance absorption, determinate on to experimental spectrum, proportional amount paramagnetic fraction in substances. In connection therewith is direct research up to analytic definition of concentration paramagnetic centers in substances

1978-01-01

185

Finding a compromise between chemical and radiological risk assessment methods for mixed waste sites  

International Nuclear Information System (INIS)

The purpose of this paper is to (1) outline the fundamental similarities and differences between the presently accepted radiological and chemical risk assessment methods, (2) examine the significant differences in analytical results and decision making that can result if either is used to the exclusion of the other and (3) to suggest a hybrid method that utilizes the strong points of each to arrive at a balanced contaminant impact data base for decision making. The approach taken to facilitate these comparisons is to quantitatively assess the collective risk at a simplified site, contaminated with a short list of chemicals and radionuclides. The site is assessed first using exclusively the suggested Superfund toxic chemical methodology for both chemicals and radionuclides, followed by the same analysis using accepted radiological methods for both contaminant categories. Both the methods and the results of these calculations are compared and contrasted. Logical mitigation decisions that might result from each set of calculations are examined. The same site is finally analyzed using a method that incorporates the best of both of the previously used methods and the results are analyzed on the basis of the decision-making utility of the results. Conclusions are drawn relative to several topics or prime importance. These are: acceptable risk bases, key assumptions, statistical inputs, prioritizing contaminants, environmental models, cumulative risk, and risk assessments for non-human receptors.

1990-11-02

186

Finding confidence limits on population growth rates: bootstrap and analytic methods.  

UK PubMed Central (United Kingdom)

When predicting population dynamics, the value of the prediction is not enough and should be accompanied by a confidence interval that integrates the whole chain of errors, from observations to predictions via the estimates of the parameters of the model. Matrix models are often used to predict the dynamics of age- or size-structured populations. Their parameters are vital rates. This study aims (1) at assessing the impact of the variability of observations on vital rates, and then on model's predictions, and (2) at comparing three methods for computing confidence intervals for values predicted from the models. The first method is the bootstrap. The second method is analytic and approximates the standard error of predictions by their asymptotic variance as the sample size tends to infinity. The third method combines use of the bootstrap to estimate the standard errors of vital rates with the analytical method to then estimate the errors of predictions from the model. Computations are done for an Usher matrix models that predicts the asymptotic (as time goes to infinity) stock recovery rate for three timber species in French Guiana. Little difference is found between the hybrid and the analytic method. Their estimates of bias and standard error converge towards the bootstrap estimates when the error on vital rates becomes small enough, which corresponds in the present case to a number of observations greater than 5000 trees.

Picard N; Chagneau P; Mortier F; Bar-Hen A

2009-05-01

187

Using centroid time-delays to characterize source durations and identify earthquakes with unique characteristics  

Science.gov (United States)

The relationship between M0 and the rupture duration is often difficult to establish. This is particularly true for large earthquakes for which the moment rate functions (MRF) generally have complicated shapes, and the estimated durations can vary considerably depending on the methodology used to evaluate the MRF. In this work, we show that the centroid time-delay (?c) provides an alternative estimate of the source duration. Inverted MRFs often end gradually, making the end of coseismic rupture difficult to detect. In such cases, when the rupture duration is not well defined, the time-delay ?c is a useful quantity to represent the first-order temporal characteristics of the rupture process. Variations in stress parameter ?? can be investigated by assuming a standard scaling relationship between the seismic moment M0 and ?c. This simple scaling relationship can also be used to identify unusual earthquakes, with unique source properties, such as events involving complicated rupture processes or earthquakes characterized by unusual rupture velocities, stress drops or aspect ratios.

Duputel, Zacharie; Tsai, Victor C.; Rivera, Luis; Kanamori, Hiroo

2013-07-01

188

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

189

The Velocity Centroid Periodicity of L2 Puppis' SiO Maser Emission  

Science.gov (United States)

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.; Indermuehle, Balthasar

2013-09-01

190

THE VELOCITY CENTROID PERIODICITY OF L2 PUPPIS' SiO MASER EMISSION  

International Nuclear Information System (INIS)

[en] 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

2013-09-01

191

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

1997-08-01

192

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

Directory of Open Access Journals (Sweden)

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.

Xia Wu; Xiong Yu; Hao Jing

2011-01-01

193

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.

Clare O'Callaghan; Philippa Barry

2009-01-01

194

[Direct measurement of venous pressure in the lower limbs. Methods and findings  

UK PubMed Central (United Kingdom)

The authors discuss the determination of the venous pressure as a routine examination. They describe their method and specify in turn : -- the choice of the place of determination : the dorsal venous arch of the foot ; -- the choice of the type of overload : stepping on site with toes in extension ; -- the surrounding temperature : a diminution of the room temperature considerably affecting the filling time ; -- the investigation, for therapeutic purposes, of the causes of venous insufficiency, putting pneumatic cuffs at various levels. Finally the authors explain this method by means of some examples of results obtained.

Kuiper JP; Brakkee AJ

1978-07-01

195

An efficient search method for finding the critical slip surface using the compositional Monte Carlo technique  

International Nuclear Information System (INIS)

[en] Locating the critical slip surface and the associated minimum factor of safety are two complementary parts in a slope stability analysis. A large number of computer programs exist to solve slope stability problems. Most of these programs, however, have used inefficient and unreliable search procedures to locate the global minimum factor of safety. This paper presents an efficient and reliable method to determine the global minimum factor of safety coupled with a modified version of the Monte Carlo technique. Examples arc presented to illustrate the reliability of the proposed method

2008-01-01

196

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Problem statement: A homotopy method has proven to be reliable for computing all of the isolated solutions of a multivariate polynomial system. The multi-homogeneous Bézout number of a polynomial system is the number of paths that one has to trace in order to compute all of its isolated solut...

Hassan M.S. Bawazir; Ali A. Rahman

197

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.

G. S. Doiphode; S. C. Patodi

2012-01-01

198

Finding Simple Rules for Discriminating Folding Rate Change upon Single Mutation by Statistical and Learning Methods.  

UK PubMed Central (United Kingdom)

Protein folding rate is one of the important information understanding the variations in protein folding kinetics. The accurate discrimination of protein folding rate change is helpful and useful in protein design. However, there are fewer studies on the influence of amino acid substitution to protein folding rates. In our earlier studies, we constructed a dataset of 467 mutants upon amino acid substitution and proposed novel methods for discriminating and predicting the accelerating and decelerating mutants during the folding process. Here, this work aimed to effectively develop the rules for discriminating protein folding rate change upon single point mutation. In this paper, the study constructed a non-redundant dataset F661 that consists of 661 mutants, and then analyzed the dataset systematically and implemented different data mining techniques to build discrimination rules. Furthermore, the rules obtained from different methods were interpreted, evaluated, compared and integrated. The results showed that the present approach may effectively develop the knowledge from these mutants and the rule quality may be improved by combining the statistical and learning methods, which increases the understanding of discriminating protein folding rate change upon single mutation. The details of the rules along with relevant information have been integrated and available freely at http://bioinformatics.myweb.hinet.net/rulefr.htm.

Huang LT

2013-07-01

199

Inventory methods for finding historically cultivated hop (Humulus lupulus L.) in Sweden  

UK PubMed Central (United Kingdom)

The relationship between the conservation of plant genetic resources and their culture history is intimate. Consequently, biodiversity research must also take into account historical and cultural factors. An inventory of plants collected from all over Sweden was made with the aim of establishing a national Swedish gene bank for once cultivated hop. Only female hop, which could be regarded as cultivated hop on the basis of history, were selected. In this study, two different inventory methods were used: one based on plant habitat and the other involving the use of historical documents, primarily large-scale maps from the first half of the seventeenth century, used to locate their cultivars today. The documented history of the hop, combined with its biology, is the basis for the methods used. Hop is the only Swedish crop that according to a 1442 law had to be cultivated. The law lasted for over 400 years. Since the hop is a perennial, dioecious plant and only female individuals are cultivated, over time very few genetic recombination events are expected. Today, it is possible to connect and identify living plants using historical documents. The degree of connection between today's living plants and the historical evidence for hop cultivation differ between the two methods.

Strese Else-MarieKarlsson; Karsvall Olof; Tollin Clas

2010-02-01

200

A method for finding consensus breakpoints in the cancer genome from copy number data.  

UK PubMed Central (United Kingdom)

MOTIVATION: Recurrent DNA breakpoints in cancer genomes indicate the presence of critical functional elements for tumor development. Identifying them can help determine new therapeutic targets. High-dimensional DNA microarray experiments like arrayCGH afford the identification of DNA copy number breakpoints with high precision, offering a solid basis for computational estimation of recurrent breakpoint locations. RESULTS: We introduce a method for identification of recurrent breakpoints (consensus breakpoints) from copy number aberration datasets. The method is based on weighted kernel counting of breakpoints around genomic locations. Counts larger than expected by chance are considered significant. We show that the consensus breakpoints facilitate consensus segmentation of the samples. We apply our method to three arrayCGH datasets and show that by using consensus segmentation we achieve significant dimension reduction, which is useful for the task of prediction of tumor phenotype based on copy number data. We use our approach for classification of neuroblastoma tumors from different age groups and confirm the recent recommendation for the choice of age cut-off for differential treatment of 18 months. We also investigate the (epi)genetic properties at consensus breakpoint locations for seven datasets and show enrichment in overlap with important functional genomic regions. AVAILABILITY: Implementation in R of our approach can be found at http://www.mpi-inf.mpg.de/ ?laura/FeatureGrouping.html. CONTACT: laura@mpi-inf.mpg.de. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Tolo?i L; Theißen J; Halachev K; Hero B; Berthold F; Lengauer T

2013-07-01

 
 
 
 
201

A new method for finding clusters of galaxies at z>1  

CERN Document Server

At large redshifts, a cluster or group may be too distant for the galaxies within the cluster to be detected individually. However, the light from these ``undetected'' galaxies still modulates the surface brightness of the background sky. Clusters can appear as 10"-1.5' sized fluctuations in the surface brightness of the EBL. The fluctuations have central surface brightnesses between roughly 26 and 28 mag/sqr-arcsec (in V) for clusters between z=1 and z=2, and are brighter than the fluctuations produced by background field galaxies. While such low surface brightnesses are difficult to achieve with direct high-resolution imaging, we demonstrate that they are easily reached in short exposures through smoothing the sky in very flat CCD images. For a reasonable extrapolation of the properties and space densities of clusters and groups, we find that for a wide range of cosmological assumptions there should be tens of clusters per square degree visible in the extragalactic background. The detection rate can range b...

Dalcanton, J J

1994-01-01

202

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

CERN Multimedia

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 telescopes. We have so far analysed over 350 square degrees and found 770 brown dwarf candidates brighter than z'{AB}=22.5. We currently have J-band photometry for 220 of these candidates, which confirms 37% as potential L or T dwarfs. Some are among the reddest and farthest brown dwarfs currently known, including an independent identification of the recently published ULAS J003402.77-005206.7 and the discovery of a second brown dwarf later than T8, CFBDS J005910.83-011401.3. Infrared spectra of three T dwarf candidates ...

Delorme, Philippe; Forveille, Thierry; Delfosse, Xavier; Reylé, Céline; Bertin, Emmanuel; Albert, Loic; Artigau, Etienne; Robin, Annie C; Allard, France; Doyon, Rene; Hill, Gary J

2008-01-01

203

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

Science.gov (United States)

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

Boyd, John P.

2013-08-01

204

Finding future high-cost cases: comparing prior cost versus diagnosis-based methods.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To examine the value of two kinds of patient-level dat a (cost and diagnoses) for identifying a very small subgroup of a general population with high future costs that may be mitigated with medical management. DATA SOURCES: The study used the MEDSTAT Market Scan (R) Research Database, consisting of inpatient and ambulatory health care encounter records for individuals covered by employee- sponsored benefit plans during 1997 and 1998. STUDY DESIGN: Prior cost and a diagnostic cost group (DCG) risk model were each used with 1997 data to identify 0.5-percent-sized "top groups" of people most likely to be expensive in 1998. We compared the distributions of people, cost, and diseases commonly targeted for disease management for people in the two top groups and, as a bench mark, in the full population. PRINCIPAL FINDINGS: the prior cost- and DCG-identified top groups overlapped by only 38 percent. Each top group consisted of people with high year-two costs and high rates of diabetes, heart failure, major lung disease, and depression. The DCG top group identified people who are both somewhat more expensive ($27,292 vs. $25,981) and more likely ( 49.4 percent vs. 43.8 percent ) th an the prior-cost top group to have at least one of the diseases commonly targeted for disease management. The overlap group average cost was $46,219. CONCLUSIONS: Diagnosis-based risk models are at least as powerful as prior cost for identifying people who will be expensive. Combined cost and diagnostic data are even more powerful and more operation ally useful, especially because the diagnostic information identifies the medical problems that may be managed to achieve better out comes and lower costs.

Ash AS; Zhao Y; Ellis RP; Schlein Kramer M

2001-12-01

205

1001 optimal PDB structure alignments: integer programming methods for finding the maximum contact map overlap.  

UK PubMed Central (United Kingdom)

Protein structure comparison is a fundamental problem for structural genomics, with applications to drug design, fold prediction, protein clustering, and evolutionary studies. Despite its importance, there are very few rigorous methods and widely accepted similarity measures known for this problem. In this paper we describe the last few years of developments on the study of an emerging measure, the contact map overlap (CMO), for protein structure comparison. A contact map is a list of pairs of residues which lie in three-dimensional proximity in the protein's native fold. Although this measure is in principle computationally hard to optimize, we show how it can in fact be computed with great accuracy for related proteins by integer linear programming techniques. These methods have the advantage of providing certificates of near-optimality by means of upper bounds to the optimal alignment value. We also illustrate effective heuristics, such as local search and genetic algorithms. We were able to obtain for the first time optimal alignments for large similar proteins (about 1,000 residues and 2,000 contacts) and used the CMO measure to cluster proteins in families. The clusters obtained were compared to SCOP classification in order to validate the measure. Extensive computational experiments showed that alignments which are off by at most 10% from the optimal value can be computed in a short time. Further experiments showed how this measure reacts to the choice of the threshold defining a contact and how to choose this threshold in a sensible way.

Caprara A; Carr R; Istrail S; Lancia G; Walenz B

2004-01-01

206

1001 optimal PDB structure alignments: integer programming methods for finding the maximum contact map overlap.  

Science.gov (United States)

Protein structure comparison is a fundamental problem for structural genomics, with applications to drug design, fold prediction, protein clustering, and evolutionary studies. Despite its importance, there are very few rigorous methods and widely accepted similarity measures known for this problem. In this paper we describe the last few years of developments on the study of an emerging measure, the contact map overlap (CMO), for protein structure comparison. A contact map is a list of pairs of residues which lie in three-dimensional proximity in the protein's native fold. Although this measure is in principle computationally hard to optimize, we show how it can in fact be computed with great accuracy for related proteins by integer linear programming techniques. These methods have the advantage of providing certificates of near-optimality by means of upper bounds to the optimal alignment value. We also illustrate effective heuristics, such as local search and genetic algorithms. We were able to obtain for the first time optimal alignments for large similar proteins (about 1,000 residues and 2,000 contacts) and used the CMO measure to cluster proteins in families. The clusters obtained were compared to SCOP classification in order to validate the measure. Extensive computational experiments showed that alignments which are off by at most 10% from the optimal value can be computed in a short time. Further experiments showed how this measure reacts to the choice of the threshold defining a contact and how to choose this threshold in a sensible way. PMID:15072687

Caprara, Alberto; Carr, Robert; Istrail, Sorin; Lancia, Giuseppe; Walenz, Brian

2004-01-01

207

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

2006-01-01

208

3D Superalloy Grain Segmentation Using a Multichannel Edge-Weighted Centroidal Voronoi Tessellation Algorithm.  

UK PubMed Central (United Kingdom)

Accurate grain segmentation on 3D superalloy images is very important in materials science and engineering. From grain segmentation, we can derive the underlying superalloy grains' micro-structures, based on how many important physical, mechanical, and chemical properties of the superalloy samples can be evaluated. Grain segmentation is, however, usually a very challenging problem because: 1) even a small 3D superalloy sample may contain hundreds of grains; 2) carbides and noises may degrade the imaging quality; and 3) the intensity within a grain may not be homogeneous. In addition, the same grain may present different appearances, e.g., different intensities, under different microscope settings. In practice, a 3D superalloy image may contain multichannel information where each channel corresponds to a specific microscope setting. In this paper, we develop a multichannel edge-weighted centroidal Voronoi tessellation (MCEWCVT) algorithm to effectively and robustly segment the superalloy grains from 3D multichannel superalloy images. MCEWCVT performs segmentation by minimizing an energy function, which encodes both the multichannel voxel-intensity similarity within each cluster in the intensity domain and the smoothness of segmentation boundaries in the 3D image domain. In the experiment, we first quantitatively evaluate the proposed MCEWCVT algorithm on a four-channel Ni-based 3D superalloy data set (IN100) against the manually annotated ground-truth segmentation. We further evaluate the MCEWCVT algorithm on two synthesized four-channel superalloy data sets. The qualitative and quantitative comparisons of 18 existing image segmentation algorithms demonstrate the effectiveness and robustness of the proposed MCEWCVT algorithm.

Cao Y; Ju L; Zhou Y; Wang S

2013-10-01

209

3D Superalloy Grain Segmentation Using a Multichannel Edge-Weighted Centroidal Voronoi Tessellation Algorithm.  

Science.gov (United States)

Accurate grain segmentation on 3D superalloy images is very important in materials science and engineering. From grain segmentation, we can derive the underlying superalloy grains' micro-structures, based on how many important physical, mechanical, and chemical properties of the superalloy samples can be evaluated. Grain segmentation is, however, usually a very challenging problem because: 1) even a small 3D superalloy sample may contain hundreds of grains; 2) carbides and noises may degrade the imaging quality; and 3) the intensity within a grain may not be homogeneous. In addition, the same grain may present different appearances, e.g., different intensities, under different microscope settings. In practice, a 3D superalloy image may contain multichannel information where each channel corresponds to a specific microscope setting. In this paper, we develop a multichannel edge-weighted centroidal Voronoi tessellation (MCEWCVT) algorithm to effectively and robustly segment the superalloy grains from 3D multichannel superalloy images. MCEWCVT performs segmentation by minimizing an energy function, which encodes both the multichannel voxel-intensity similarity within each cluster in the intensity domain and the smoothness of segmentation boundaries in the 3D image domain. In the experiment, we first quantitatively evaluate the proposed MCEWCVT algorithm on a four-channel Ni-based 3D superalloy data set (IN100) against the manually annotated ground-truth segmentation. We further evaluate the MCEWCVT algorithm on two synthesized four-channel superalloy data sets. The qualitative and quantitative comparisons of 18 existing image segmentation algorithms demonstrate the effectiveness and robustness of the proposed MCEWCVT algorithm. PMID:23797261

Cao, Yu; Ju, Lili; Zhou, Youjie; Wang, Song

2013-06-19

210

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 placing the calibration reference signal feeding network on the microstrip antenna array bearer, directly beside the antenna patches. It is combined with orthogonal spread spectrum calibration signal utility for continuous uninterrupted measurements. The spread spectrum calibration signal is orthogonal to the continuous wave (CW) signal to be measured, therefore, the 2 signals can be separated in the receiver, enabling them to be present simultaneously. DOA measurement results are shown, measured with the realized integrated microstrip patch antenna array with calibration network hardware.

A. Magyar; G. Miko; R. Seller

2007-01-01

211

Training in Information Management for Army Brigade and Battalion Staff: Methods and Preliminary Findings  

Canada Institute for Scientific and Technical Information (Canada)

Training, training Support software, and measurement instruments were developed to help Army brigade and below staff manage information and overcome information overload in a digital messaging environment. Development of the training was guided by two theoretical models: a model of team adaptations to stress and a model of adaptive decision making. The instruction focused on selected skills concerning critical thinking and team coordination. The results of a pilot study suggest that training may have beneficial effects on the targeted skills. Measures of decision accuracy, decision making processes, information filtering, and information production were developed. Methods of automating the training and measures, and approaches to feedback and adaptation of instruction, practice, and testing are described. Concepts for a system architecture are presented.

1997-01-01

212

Finding Disease Variants in Mendelian Disorders By Using Sequence Data: Methods and Applications  

Science.gov (United States)

Many sequencing studies are now underway to identify the genetic causes for both Mendelian and complex traits. Via exome-sequencing, genes harboring variants implicated in several Mendelian traits have already been identified. The underlying methodology in these studies is a multistep algorithm based on filtering variants identified in a small number of affected individuals and depends on whether they are novel (not yet seen in public resources such as dbSNP), shared among affected individuals, and other external functional information on the variants. Although intuitive, these filter-based methods are nonoptimal and do not provide any measure of statistical uncertainty. We describe here a formal statistical approach that has several distinct advantages: (1) it provides fast computation of approximate p values for individual genes, (2) it adjusts for the background variation in each gene, (3) it allows for incorporation of functional or linkage-based information, and (4) it accommodates designs based on both affected relative pairs and unrelated affected individuals. We show via simulations that the proposed approach can be used in conjunction with the existing filter-based methods to achieve a substantially better ranking of a gene relevant for disease when compared to currently used filter-based approaches, this is especially so in the presence of disease locus heterogeneity. We revisit recent studies on three Mendelian diseases and show that the proposed approach results in the implicated gene being ranked first in all studies, and approximate p values of 10?6 for the Miller Syndrome gene, 1.0 × 10?4 for the Freeman-Sheldon Syndrome gene, and 3.5 × 10?5 for the Kabuki Syndrome gene.

Ionita-Laza, Iuliana; Makarov, Vlad; Yoon, Seungtai; Raby, Benjamin; Buxbaum, Joseph; Nicolae, Dan L.; Lin, Xihong

2011-01-01

213

Hidden outpatient oncology clinical nursing minimum data set: findings from an Italian multi-method study.  

UK PubMed Central (United Kingdom)

PURPOSE: The main aim of this study was to present the hidden Clinical Nursing Minimum Data Set adopted by Italian nurses in outpatient oncology settings. METHODS: A multi-method study design articulated in three phases was conducted from November 2009 to December 2010. A cross-sectional study design involving outpatient oncology centres located in the 20 Italian regions was undertaken in order to collect structured nursing records used by nurses in the documentation of daily nursing care. An evaluation of the items contained in each nursing record was performed in order to individuate homogeneities. A content analysis of the items was therefore undertaken in order to categorise them in assessment, problems, intervention, and outcomes. RESULTS: A total of 1080 different items from the structured nursing records were counted, comprising on average 29 items (range 8-175; ±40.4) for each record. A total of 330 (30.6%) out of 1080 were categorised as assessment items, 146 (13.5%) as problems, 583 (54.0%) as interventions and 21 (1.9%) as outcomes items. CONCLUSION: Italian nurses have developed a micro-system Clinical Nursing Minimum Data Set capturing and documenting several types of clinical data, following their implicit representation of what it is important to document: much consideration is given to nursing surveillance/monitoring and to at-risk problems, indicating the importance of the nursing role in the prevention and early recognition of a patient's clinical deterioration. However, there is a need to develop a macro-system national NMDS which will be useful for evaluating nursing outcomes and making decisions on workforce resources.

Palese A; Zanini A; Carlevaris E; Morandin A; Carpanelli I; Dante A

2013-08-01

214

The energy dependence of the centroid frequency and phase lag of the QPOs in GRS 1915+105  

CERN Document Server

We present a study of the centroid frequencies and phase lags of the quasi-periodic oscillations (QPOs) as functions of photon energy for GRS 1915+105. It is found that the centroid frequencies of the 0.5-10 Hz QPOs and their phase lags are both energy dependent, and there exists an anti-correlation between the QPO frequency and phase lag. These new results challenge the popular QPO models, because none of them can fully explain the observed properties. We suggest that the observed QPO phase lags are partially due to the variation of the QPO frequency with energy, especially for those with frequency higher than 3.5 Hz.

Qu, J L; Lu, Y; Song, M L; Zhang, S; Ding, G Q

2009-01-01

215

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

International Nuclear Information System (INIS)

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

2004-01-01

216

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-04-01

217

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

International Nuclear Information System (INIS)

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

2003-01-01

218

Novel survey method finds dramatic decline of wild cotton-top tamarin population.  

UK PubMed Central (United Kingdom)

The cotton-top tamarin (Saguinus oedipus) is a critically endangered primate, endemic to the tropical forests of Colombia. Population monitoring is essential to evaluate the success of conservation efforts, yet standard survey methods are ineffective because animals flee silently before they are seen. We developed a novel technique that combines the use of playbacks of territorial vocalizations with traditional transect surveys. We used remote sensing to identify potential habitat within the species' historic range, and visited the 27% that we could survey safely. Of this, only 99 km(2) was extant forest, containing an estimated 2,045 animals (95% confidence interval 1,587-2,634). Assuming comparable densities in non-surveyed areas, approximately 7,394 wild cotton-top tamarins remain in Colombia. With 20-30,000 animals exported to the United States in the late 1960s, this must represent a precipitous decline. Habitat destruction and capture for the illegal pet trade are ongoing. Urgent conservation measures are required to prevent extinction in the wild.

Savage A; Thomas L; Leighty KA; Soto LH; Medina FS

2010-01-01

219

A COMPARATIVE STUDY TO FIND A SUITABLE METHOD FOR TEXT DOCUMENT CLUSTERING  

Directory of Open Access Journals (Sweden)

Full Text Available Text mining is used in various text related tasks such as information extraction, concept/entity extraction,document summarization, entity relation modeling (i.e., learning relations between named entities),categorization/classification and clustering. This paper focuses on document clustering, a field of textmining, which groups a set of documents into a list of meaningful categories. The main focus of thispaper is to present a performance analysis of various techniques available for document clustering. Theresults of this comparative study can be used to improve existing text data mining frameworks andimprove the way of knowledge discovery. This paper considers six clustering techniques for documentclustering. The techniques are grouped into three groups namely Group 1 - K-means and its variants(traditional K-means and K* Means algorithms), Group 2 - Expectation Maximization and its variants(traditional EM, Spherical Gaussian EM algorithm and Linear Partitioning and Reallocation clustering(LPR) using EM algorithms), Group 3 - Semantic-based techniques (Hybrid method and Feature-basedalgorithms). A total of seven algorithms are considered and were selected based on their popularity inthe text mining field. Several experiments were conducted to analyze the performance of the algorithmand to select the winner in terms of cluster purity, clustering accuracy and speed of clustering.

Mrs.S.C.Punitha; Dr.M.Punithavalli

2012-01-01

220

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

 
 
 
 
221

Dragon method for finding novel tyrosinase inhibitors: Biosilico identification and experimental in vitro assays.  

Science.gov (United States)

QSAR (quantitative structure-activity relationship) studies of tyrosinase inhibitors employing Dragon descriptors and linear discriminant analysis (LDA) are presented here. A data set of 653 compounds, 245 with tyrosinase inhibitory activity and 408 having other clinical uses were used. The active data set was processed by k-means cluster analysis in order to design training and prediction series. Seven LDA-based QSAR models were obtained. The discriminant functions applied showed a globally good classification of 99.79% for the best model Class=-96.067+1.988 x 10(2)X0Av +9 1.907 BIC3 + 6.853 CIC1 in the training set. External validation processes to assess the robustness and predictive power of the obtained model were carried out. This external prediction set had an accuracy of 99.44%. After that, the developed models were used in ligand-based virtual screening of tyrosinase inhibitors from the literature and never considered in either training or predicting series. In this case, all screened chemicals were correctly classified by the LDA-based QSAR models. As a final point, these fitted models were used in the screening of new bipiperidine series as new tyrosinase inhibitors. These methods are an adequate alternative to the process of selection/identification of new bioactive compounds. The biosilico assays and in vitro results of inhibitory activity on mushroom tyrosinase showed good correspondence. It is important to stand out that compound BP4 (IC(50)=1.72 microM) showed higher activity in the inhibition against the enzyme than reference compound kojic acid (IC(50)=16.67 microM) and l-mimosine (IC(50)=3.68 microM). These results support the role of biosilico algorithm for the identification of new tyrosinase inhibitor compounds. PMID:17637486

Casañola-Martín, Gerardo M; Marrero-Ponce, Yovani; Khan, Mahmud Tareq Hassan; Ather, Arjumand; Khan, Khalid M; Torrens, Francisco; Rotondo, Richard

2007-02-23

222

Digital animation as a method to disseminate research findings to the community using a community-based participatory approach.  

UK PubMed Central (United Kingdom)

Community-based participatory research (CBPR) has garnered increasing interest over the previous two decades as researchers have tackled increasingly complex health problems. In academia, professional presentations and articles are major ways that research is disseminated. However, dissemination of research findings to the people and communities who participated in the research is many times forgotten. In addition, little scholarly literature is focused on creative dissemination of research findings to the community using CBPR methods. We seek to fill this gap in the literature by providing an exemplar of research dissemination and partnership strategies that were used to complete this project. In this paper, we present a novel approach to the dissemination of research findings to our targeted communities through digital animation. We also provide the foundational thinking and specific steps that were taken to select this specific dissemination product development and distribution strategy.

Vaughn NA; Jacoby SF; Williams T; Guerra T; Thomas NA; Richmond TS

2013-03-01

223

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

Science.gov (United States)

The centroid-moment-tensor (CMT) algorithm provides a straightforward, rapid method for the determination of seismic source parameters from waveform data. As such, it has found widespread application, and catalogues of CMT solutions - particularly the catalogue maintained by the Global CMT Project - are routinely used by geoscientists. However, there have been few attempts to quantify the uncertainties associated with any given CMT determination: whilst catalogues typically quote a 'standard error' for each source parameter, these are generally accepted to significantly underestimate the true scale of uncertainty, as all systematic effects are ignored. This prevents users of source parameters from properly assessing possible impacts of this uncertainty upon their own analysis. The CMT algorithm determines the best-fitting source parameters within a particular modelling framework, but any deficiencies in this framework may lead to systematic errors. As a result, the minimum-misfit source may not be equivalent to the 'true' source. We suggest a pragmatic solution to uncertainty assessment, based on accepting that any 'low-misfit' source may be a plausible model for a given event. The definition of 'low-misfit' should be based upon an assessment of the scale of potential systematic effects. We set out how this can be used to estimate the range of values that each parameter might take, by considering the curvature of the misfit function as minimised by the CMT algorithm. This approach is computationally efficient, with cost similar to that of performing an additional iteration during CMT inversion for each source parameter to be considered. The source inversion process is sensitive to the various choices that must be made regarding dataset, earth model and inversion strategy, and for best results, uncertainty assessment should be performed using the same choices. Unfortunately, this information is rarely available when sources are obtained from catalogues. As already indicated by Valentine and Woodhouse (2010), researchers conducting comparisons between data and synthetic waveforms must ensure that their approach to forward-modelling is consistent with the source parameters used; in practice, this suggests that they should consider performing their own source inversions. However, it is possible to obtain rough estimates of uncertainty using only forward-modelling.

Valentine, Andrew P.; Trampert, Jeannot

2012-11-01

224

Method for finding round trip routes on road network data. Doro nettowaku ni okeru junkai haiso keiro tansaku  

Energy Technology Data Exchange (ETDEWEB)

In recent years, with the development of computer map-making technique, researches concerning geographic data base for displaying maps in computers in digital form and for storing, managing, searching and processing the map data have become very popular. In this paper, a heuristic route finding algorithm was proposed for finding the shortest round trip route rounding arbitrary plural nodes on road network data stored in digital road maps so as to raise the efficiency of the circulating system. This method for finding round trip routes is based on the fact that when people look at a map and decide the shortest round trip route, they would imagine a frame including all tour nodes and then decide the approximate route. In order to verify the result of the method of this paper the time complexity of the proposed algorithm was analyzed and simulation experiments were carried out. The practice time and accuracy obtained were compared with those of the greedy method and the hopfield type neural network. 18 refs., 5 figs.

Uchimura, K.; Kanki, K. (Kumamoto Univ., Kumamoto (Japan))

1994-04-20

225

Lecturers and students as stakeholders for education commissioning for learning disability nursing: Focus group findings from a multiple method study.  

UK PubMed Central (United Kingdom)

BACKGROUND: In England, the numbers of learning disability nurses are declining; a need for urgent attention to workforce planning issues has been advocated. This paper considers views of lecturers, students and potential students as legitimate stakeholders for future education commissioning for this field of nursing. OBJECTIVES: This project aimed to undertake a strategic review of learning disability nursing educational commissioning, to provide an 'evidence based' evaluation to inform future strategic commissioning of learning disability nursing for one Health Authority, UK. DESIGN: The project adopted a structured multiple methods approach to generate evidence from a number of data sources, this paper reports on the findings from one method [focus groups] used for two groups of stakeholders. INFORMANTS: Informants comprised 10 learning disability nursing students studying at a Higher Education Institution, 25 health and social care students studying at a Further Education College, and 6 academic staff from 5 universities; all informants were from the south of England. METHODS: The method reported on in this paper is focus group methodology. Once completed, transcripts made were read in full, and subjected to content analysis. RESULTS: The process of content analysis led to the development of 11 theoretical categories that describe the multiplicity of views of informants, as to issues of importance for this element of the health workforce. CONCLUSION: The paper concludes by identifying key messages from these informants. It is suggested that both method and findings have national and international resonance, as stakeholder engagement is a universal issue in health care education commissioning.

Gates B; Statham M

2013-10-01

226

The centroid shift of the 5d levels of Ce3+ with respect to the 4f levels in ionic crystals, a theoretical investigation  

International Nuclear Information System (INIS)

[en] The centroid shifts of the 5d level of Ce3+ in BaF2, LaAlO3 and LaCl3 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

2002-06-21

227

Franck-Condon factors and r-centroids for the B-X bands of 10B18O and 11B18O molecules  

Directory of Open Access Journals (Sweden)

Full Text Available Frank–Condon factors and r-centroids have been calculated for the B2S+ –X2S+ bands of the 10B18O and 11B18O isotopic molecules assuming that both the B and X states follow a Morse potential curve. The calculated q n'n" values are compared with observed band intensities and the relationship between the r-centroids and the band positions has been determined and is discussed.

MIROSLAV KUZMANOVIC; ANKICA ANTIC-JOVANOVIC; DIMITRIJE PESIC; VOJISLAV BOJOVIC

2005-01-01

228

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 Multimedia

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

229

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2003-07-01

230

Paradigm shift in gene-finding method: From bench-top approach to desk-top approach (review).  

Science.gov (United States)

Gene-finding methods are classified into homology-based bench-top approach (degenerate cDNA-PCR and cDNA selection), ab initio bench-top approach (cDNA subtraction, two-hybrid system, and exon trapping), homology-based desk-top approach (BLAST search), ab initio desk-top approach (Fgenesh and GENSCAN programs), and hybrid desk-top approach (GenomeScan program). cDNA-library screening, cDNA-PCR, and RACE are used to isolate cDNAs for complete coding sequences. Because WNT signaling molecules are potent targets for oncology, regenerative medicine, and other fields of medical science, we have cloned and characterized many human genes encoding WNT signaling molecules, including 13 out of 19 human WNT genes, and 9 out of 10 human FZD genes. We used degenerate cDNA-PCR and cDNA-library screening in the 20th century, while we use BLAST program and cDNA-PCR in the 21st century. The interval between gene-finding and manuscript-publication in my laboratory was 17.2+/-7.5 (mean +/- SD) months in the 20th century (n=13), 11.5+/-7.8 months in 2001 (n=19), and 5.5+/-1.6 months in 2002 (n=13). The interval using desk-top gene-finding approach (7.2+/-2.6 months, n=30) was significantly shorter than that using bench-top approach (19.8+/-8.0 months, n=15) (p=0.003). Gene-finding has been significantly accelerated due to paradigm shift from bench-top approach to desk-top approach. Dramatic increase of information about human genome, transcriptome and proteome accompanied by improvements of genomics, proteonics and bioinformatics technologies will accelerate paradigm shift from bench-top science to desk-top science. PMID:12429991

Katoh, Masaru

2002-12-01

231

Paradigm shift in gene-finding method: From bench-top approach to desk-top approach (review).  

UK PubMed Central (United Kingdom)

Gene-finding methods are classified into homology-based bench-top approach (degenerate cDNA-PCR and cDNA selection), ab initio bench-top approach (cDNA subtraction, two-hybrid system, and exon trapping), homology-based desk-top approach (BLAST search), ab initio desk-top approach (Fgenesh and GENSCAN programs), and hybrid desk-top approach (GenomeScan program). cDNA-library screening, cDNA-PCR, and RACE are used to isolate cDNAs for complete coding sequences. Because WNT signaling molecules are potent targets for oncology, regenerative medicine, and other fields of medical science, we have cloned and characterized many human genes encoding WNT signaling molecules, including 13 out of 19 human WNT genes, and 9 out of 10 human FZD genes. We used degenerate cDNA-PCR and cDNA-library screening in the 20th century, while we use BLAST program and cDNA-PCR in the 21st century. The interval between gene-finding and manuscript-publication in my laboratory was 17.2+/-7.5 (mean +/- SD) months in the 20th century (n=13), 11.5+/-7.8 months in 2001 (n=19), and 5.5+/-1.6 months in 2002 (n=13). The interval using desk-top gene-finding approach (7.2+/-2.6 months, n=30) was significantly shorter than that using bench-top approach (19.8+/-8.0 months, n=15) (p=0.003). Gene-finding has been significantly accelerated due to paradigm shift from bench-top approach to desk-top approach. Dramatic increase of information about human genome, transcriptome and proteome accompanied by improvements of genomics, proteonics and bioinformatics technologies will accelerate paradigm shift from bench-top science to desk-top science.

Katoh M

2002-12-01

232

Quantitative findings from a mixed methods evaluation of once-weekly therapeutic community day services for people with personality disorder.  

UK PubMed Central (United Kingdom)

BACKGROUND: Quantitative findings are presented from a mixed methods study of four one-day-a-week therapeutic communities for people with personality disorder (qualitative findings from the same study are reported in a separate paper). The evaluation assessed both the clinical efficacy of the model and its acceptability to service users, service employees and those who refer clients to the services. AIMS: The study aimed to clarify whether one-day therapeutic communities can be effective for people with personality disorder. METHOD: Changes in the functioning of service users who attended the day services were assessed every 12 weeks for up to 1 year. RESULTS: We found significant improvements in both the mental health and social functioning of service users. Changes in patterns of self-harm and service use were suggestive of possible underlying improvements but failed to reach significance levels. We also found evidence of the possible offset of costs within 16 months of an individual leaving one of the services. CONCLUSIONS: This study suggests one-day therapeutic communities may be both clinically- and cost-effective for people with personality disorder.

Barr W; Kirkcaldy A; Horne A; Hodge S; Hellin K; Göpfert M

2010-10-01

233

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 3D radial MRI  

CERN Multimedia

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 when the raw data and image data are related through the Fourier relationship as in q-space diffusion MRI and 3D radial MRI. Currently, it is extremely challenging to generate large uniform antipodally symmetric point sets suitable for 3D radial MRI. A novel approach is proposed to solve this important and long-standing problem. Methods: The proposed method is based upon constrained centroidal Voronoi tessellations of the upper hemisphere with a novel pseudometric. Geometrically intuitive approach to tessellating the upper hemisphere is also proposed. Results: The average time complexity of the proposed centroidal tessellations was shown to be effectively on the order of the product of the number of iterations and the number of generators. For small sample size, the proposed method was comparable to the state-of-the-art iterative method in terms ...

Koay, Cheng Guan

2012-01-01

234

A Body-oriented Method for Finding a Linear Form of the Dynamic Equation of Fully Parallel Robots  

UK PubMed Central (United Kingdom)

In order to identify the dynamic parameters in nonlinear adaptive control the robot's dynamic equation has to be written in a linear form. Many methods have been proposed for serial robots, but for parallel robots, the few solutions proposed so far lead to complicated equations that are not readily usable for real-time implementation. In this paper we propose a new method based on the virtual work principle to find a linear form of the dynamic equation of robots. Compared to other methods, it has the advantage that it does not need to open the closed loop structure into a tree-structure robot. It considers rather each body separately using its Jacobian matrix to project the forces into the joint space of the robot. Thus, simplification can be made at the very beginning of the modeling. This is very efficient when used to model fully parallel robots. As an illustration, the proposed method is applied to the 3 dof DELTA parallel robot.

A. Codourey; E. Burdet

235

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

UK PubMed Central (United Kingdom)

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. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res XX:1-12, 2013.

Beveridge JE; Heard BJ; Shrive NG; Frank CB

2013-07-01

236

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

CERN Multimedia

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

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

2003-01-01

237

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 from 126 men and women aged over 60 within a randomised controlled trial. Participants received a full welfare benefits assessment which successfully identified additional financial and non-financial resources for 60% of them. A range of demographic, health and social outcome measures were assessed at baseline, 6, 12 and 24 month follow up. Qualitative data were collected from a sub-sample of 25 participants purposively selected to take part in individual interviews to examine the perceived impact of welfare rights advice. Results Separate analysis of the quantitative and qualitative data revealed discrepant findings. The quantitative data showed little evidence of significant differences of a size that would be of practical or clinical interest, suggesting that the intervention had no impact on these outcome measures. The qualitative data suggested wide-ranging impacts, indicating that the intervention had a positive effect. Six ways of further exploring these data were considered: (i) treating the methods as fundamentally different; (ii) exploring the methodological rigour of each component; (iii) exploring dataset comparability; (iv) collecting further data and making further comparisons; (v) exploring the process of the intervention; and (vi) exploring whether the outcomes of the two components match. Conclusion The study demonstrates how using mixed methods can lead to different and sometimes conflicting accounts and, using this six step approach, how such discrepancies can be harnessed to interrogate each dataset more fully. Not only does this enhance the robustness of the study, it may lead to different conclusions from those that would have been drawn through relying on one method alone and demonstrates the value of collecting both types of data within a single study. More widespread use of mixed methods in trials of complex interventions is likely to enhance the overall quality of the evidence base.

Moffatt Suzanne; White Martin; Mackintosh Joan; Howel Denise

2006-01-01

238

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

UK PubMed Central (United Kingdom)

Abstract 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.

Baú TR; Garcia S; Ida EI

2013-07-01

239

Franck-Condon factors, r-centroids electronic transition moments, and Einstein coefficients for many nitrogen and oxygen band systems. Technical report, 1 Dec 89-30 Sep 91  

Energy Technology Data Exchange (ETDEWEB)

Air fluorescence models require accurate Franck-Condon factors and Einstein coefficients for analyzing the intensities of nitrogen and oxygen atom emissions produced by electron bombardment of air, such as in the aurora, high-altitude nuclear explosions, and rocket-borne electron gun experiments. In our previous report, improved vibrational and rotational constants based on the latest available spectroscopic measurements for several excited and ionic states important in air fluorescence modeling were derived. These constants have been used in the present work to calculate band origins, Franck-Condon factors, and r-centroids for many band systems of nitrogen and oxygen. These results, together with electronic transition moments obtained from published papers or derived here from published emission data and measured upper-state lifetimes, have been used to compute Einstein coefficients by the r-centroid method. Einstein coefficients by integration of the product of the electronic transition moment function and vibrational wavefunctions have also been computed for comparison. For band systems involving 'perturbed' electronic states, Einstein coefficients have been derived by simply normalizing published emission data to measured upper-state lifetimes.

Gilmore, F.R.; Laher, R.R.; Espy, P.J.

1992-02-01

240

Identificación de sitios en proteínas usando métodos de aprendizaje de máquina Finding protein sites using machine learning methods  

Directory of Open Access Journals (Sweden)

Full Text Available Con el crecimiento de las bases de datos de estructuras tridimensionales determinadas por rayos-x NMR (resonancia magnética nuclear) y de estructuras predichas por computador, se deriva la necesidad de sistemas automáticos que provean anotaciones iniciales. Se ha desarrollado un nuevo método para reconocer sitios en estructura terciaria de proteinas. El método propuesto se basa en un algoritmo previamente reportado para crear descripciones de microambientes en proteínas usando propiedades físicas y químicas con varios niveles de detalle. El método de reconocimiento toma tres entradas: 1.Un conjunto de sitios que comparte un rol funcional o estructural. 2.Un conjunto de no sitios que no tienen este rol. 3. Un sitio del cual se ignora si tiene la característica buscada o no. Se construyo un clasificador con máquina con vectores de soporte usan vectores de características en que cada componente representa una propiedad en un volumen dado. La validación contra un conjunto de prueba independiente muestra que este enfoque tiene alta sensibilidad y especificidad. También se describen los resultados de escanear cuatro proteínas con sitios de unión a calcio (con el calcio removido) usando una rejilla tridimensional de puntos de prueba separada a 1.25 ámstroms. El sistema encuentra los sitios en las proteínas ubicando puntos en los sitios de unión o cerca de estos. Los resultados muestran que puedan usarse descripciones de propiedades junto con máquinas de soporte para reconocer sitios en proteínas no anotadas.The increasing amount of protein three-dimensional (3D) structures determined by x-ray and NMR technologies as well as structures predicted by computational methods results in the need for automated methods to provide inital annotations. We have developed a new method for recognizing sites in three-dimensional protein structures. Our method is based on a previosly reported algorithm for creating descriptions of protein microenviroments using physical and chemical properties at multiple levels of detail. The recognition method takes three inputs: 1. A set of control nonsites that share some structural or functional role. 2. A set of control nonsites that lack this role. 3. A single query site. A support vector machine classifier is built using feature vectors where each component represents a property in a given volume. Validation against an independent test set shows that this recognition approach has high sensitivity and specificity. We also describe the results of scanning four calcium binding proteins (with the calcium removed) using a three dimensional grid of probe points at 1.25 angstrom spacing. The system finds the sites in the proteins giving points at or near the blinding sites. Our results show that property based descriptions along with support vector machines can be used for recognizing protein sites in unannotated structures.

Bobadilla Molina Jaime Leonardo; Niño Fernando; Mojica Tobías

2003-01-01

 
 
 
 
241

Walking and cycling to work despite reporting an unsupportive environment: insights from a mixed-method exploration of counterintuitive findings.  

UK PubMed Central (United Kingdom)

BACKGROUND: Perceptions of the environment appear to be associated with walking and cycling. We investigated the reasons for walking and cycling to or from work despite reporting an unsupportive route environment in a sample of commuters. METHODS: This mixed-method analysis used data collected as part of the Commuting and Health in Cambridge study. 1164 participants completed questionnaires which assessed the travel modes used and time spent on the commute and the perceived environmental conditions on the route to work. A subset of 50 also completed qualitative interviews in which they discussed their experiences of commuting. Participants were included in this analysis if they reported unsupportive conditions for walking or cycling on their route (e.g. heavy traffic) in questionnaires, walked or cycled all or part of the journey to work, and completed qualitative interviews. Using content analysis of these interviews, we investigated their reasons for walking or cycling. RESULTS: 340 participants reported walking or cycling on the journey to work despite unsupportive conditions, of whom 15 also completed qualitative interviews. From these, three potential explanations emerged. First, some commuters found strategies for coping with unsupportive conditions. Participants described knowledge of the locality and opportunities for alternative routes more conducive to active commuting, as well as their cycling experience and acquired confidence to cycle in heavy traffic. Second, some commuters had other reasons for being reliant on or preferring active commuting despite adverse environments, such as childcare arrangements, enjoyment, having more control over their journey time, employers' restrictions on car parking, or the cost of petrol or parking. Finally, some survey respondents appeared to have reported not their own environmental perceptions but those of others such as family members or 'the public', partly to make a political statement regarding the adversity of active commuting in their setting. CONCLUSIONS: Participants report walking and cycling to work despite adverse environmental conditions. Understanding this resilience might be just as important as investigating 'barriers' to cycling. These findings suggest that developing knowledge of safe walking and cycling routes, improving cycling confidence and restricting workplace parking may help to encourage walking and cycling to and from work.

Guell C; Panter J; Ogilvie D

2013-01-01

242

Finding Information in (Very Large) Digital Libraries: A Deep Log Approach to Determining Differences in Use According to Method of Access  

Science.gov (United States)

|This report presents the early findings of an exploratory deep log analysis (DLA) of journal usage on OhioLINK, reporting on the information seeking methods of users. Compared to the users who sought information by browsing journals, those who conducted searches to find information and articles tended to record longer session times and viewed…

Nicholas, David; Huntington, Paul; Jamali, Hamid R.; Tenopir, Carol

2006-01-01

243

Linking health and environmental data in geographical analysis: it's so much more than centroids.  

UK PubMed Central (United Kingdom)

Programs and studies increasingly use existing data from multiple sources (e.g., surveillance systems, health registries, or governmental agencies) for analysis and inference. These data usually have been collected on different geographical or spatial units, with each varying from the ones of interest. Combining such disparate data creates statistical challenges. Florida's efforts to move toward implementing the Centers for Disease Control and Prevention (CDC)'s Environmental Public Health Tracking (EPHT) program aptly illustrate these concerns, which are typical of studies designed to measure the association between environmental and health outcomes. In this paper, we develop models of spatial associations between myocardial infarctions (MIs) and ambient ozone levels in Florida during August 2005 and use these models to illustrate the problems that can occur when making inferences from aggregated data, the concept of spatial support, and the importance of correct uncertainty assessment. Existing data on hospital discharges and emergency department visits were obtained from Florida's Agency for Health Care Administration. Environmental data were obtained from Florida's Department of Environmental Protection; sociodemographic data were obtained from the US Census Bureau; and data from CDC's Behavioral Risk Factor Surveillance System were used to provide additional information on other risk factors. We highlight the opportunities and challenges associated with combining disparate spatial data for EPHT analyses. We compare the results from two different approaches to data linkage, focusing on the need to account for spatial scale and the support of spatial data in the analysis. We use geographically weighted regression, not as a visual mapping tool, but as an inferential tool designed to indicate the need for spatial coefficients, a test that cannot be made by using the majority of Bayesian models. Finally, we use geostatistical simulation methods for uncertainty analysis to demonstrate its importance in models with predicted covariates. Our focus is on relatively simple methods and concepts that can be implemented with ESRI's(®) ArcGIS(®) software.

Young LJ; Gotway CA; Yang J; Kearney G; DuClos C

2009-10-01

244

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

CERN Multimedia

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

Jacobi, Martin Nilsson

2008-01-01

245

High-resolution CT as a method of demonstrating normal and pathological findings in the petrous bone  

Energy Technology Data Exchange (ETDEWEB)

Apart from the detailed and accurate imaging of the petrous bone skeleton, high-resolution CT also supplies images of the normal and pathological intratemporal soft tissues. Owing to this wider range of findings, CT has almost completely replaced conventional tomography in the radiological imaging of the petrous bone. However, this very fact should prevent radiologists from applying high-resolution CT indiscriminately in otological radiodiagnostics.

Koester, O.; Straehler-Pohl, H.J.

1985-01-01

246

Hybrid Extragradient-Type Methods for Finding a Common Solution of an Equilibrium Problem and a Family of Strict Pseudo-Contraction Mappings  

Directory of Open Access Journals (Sweden)

Full Text Available This paper proposes a new hybrid variant of extragradient methods for finding a common solution of an equilibrium problem and a family of strict pseudo-contraction mappings. We present an algorithmic scheme that combine the idea of an extragradient method and a successive iteration method as a hybrid variant. Then, this algorithm is modified by projecting on a suitable convex set to get a better convergence property. The convergence of two these algorithms are investigated under certain assumptions.

Pham Ngoc Anh; Tran Dinh Quoc; Dang Xuan Son

2012-01-01

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

2013-01-01

248

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

249

OMERACT 10 Sharp Symposium: important findings in examination of imaging methods for measurement of joint damage in rheumatoid arthritis.  

UK PubMed Central (United Kingdom)

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

Strand V; Kingsbury SR; Woodworth T; Landewé R; Ostergaard M; Peterfy C; van der Heijde D; D'Agostino MA; Maksymowych W; Tak PP; Wells G; Conaghan PG

2011-09-01

250

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

DEFF Research Database (Denmark)

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

Strand, Vibeke; Kingsbury, Sarah R

2011-01-01

251

Plotting of liquidus surface in the system In - InP - GaAs - InAs using simplex-centroidal planning  

Energy Technology Data Exchange (ETDEWEB)

Liquidus surface in the In-InP-GaAs-InAs system is plotted using simplex-centroidal planning. The analysis of the results obtained permitted the statement that growth of indium phosphide concentration increases liquidus temperature in quasiternary cross section of the system with constant indium content, increase of indium arsenide content gives the inverse result, while change of gallium arsenide concentration does not result in essential change of liquidus temperature (at constant concentration ratio of the other two compounds).

Selin, A.A.; Vigdorovich, V.N.; Batura, V.P. (Moskovskij Inst. Ehlektronnoj Tekhniki (USSR))

1982-10-01

252

Methods dentists use to diagnose primary caries lesions prior to restorative treatment: findings from The Dental PBRN.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To (1) quantify the diagnostic techniques used by Dental Practice-Based Research Network (DPBRN) dentists before they decide to treat primary caries lesions surgically and (2) examine whether certain dentist, practice, and patient characteristics are associated with their use. METHODS: A total of 228 DPBRN dentists recorded information on 5676 consecutive restorations inserted due to primary caries lesions on 3751 patients. Practitioner-investigators placed a mean of 24.9 (SD=12.4) restorations. Lesions were categorised as posterior proximal, anterior proximal, posterior occlusal, posterior smooth, or anterior smooth. Techniques used to diagnose the lesion were categorised as clinical assessment, radiographs, and/or optical. Statistical analysis utilised generalised mixed-model ANOVA to account for the hierarchical structure of the data. RESULTS: By lesion category, the diagnostic technique combinations used most frequently were clinical assessment plus radiographs for posterior proximal (47%), clinical assessment for anterior proximal (51%), clinical assessment for posterior occlusal (46%), clinical assessment for posterior smooth (77%), and clinical assessment for anterior smooth (80%). Diagnostic technique was significantly associated with lesion category after adjusting for clustering in dentists (p<0.0001). CONCLUSION: These results - obtained during actual clinical procedures rather than from questionnaire-based hypothetical scenarios - quantified the diagnostic techniques most commonly used during the actual delivery of routine restorative care. Diagnostic technique varied by lesion category and with certain practice and patient characteristics.

Rindal DB; Gordan VV; Litaker MS; Bader JD; Fellows JL; Qvist V; Wallace-Dawson MC; Anderson ML; Gilbert GH

2010-12-01

253

DCE-MRI analysis methods for predicting the response of breast cancer to neoadjuvant chemotherapy: Pilot study findings.  

Science.gov (United States)

PURPOSE: The purpose of this pilot study is to determine (1) if early changes in both semiquantitative and quantitative DCE-MRI parameters, observed after the first cycle of neoadjuvant chemotherapy in breast cancer patients, show significant difference between responders and nonresponders and (2) if these parameters can be used as a prognostic indicator of the eventual response. METHODS: Twenty-eight patients were examined using DCE-MRI pre-, post-one cycle, and just prior to surgery. The semiquantitative parameters included longest dimension, tumor volume, initial area under the curve, and signal enhancement ratio related parameters, while quantitative parameters included K(trans) , ve , kep , vp , and ?i estimated using the standard Tofts-Kety, extended Tofts-Kety, and fast exchange regime models. RESULTS: Our preliminary results indicated that the signal enhancement ratio washout volume and kep were significantly different between pathologic complete responders from nonresponders (P?

Li, Xia; Arlinghaus, Lori R; Ayers, Gregory D; Chakravarthy, A Bapsi; Abramson, Richard G; Abramson, Vandana G; Atuegwu, Nkiruka; Farley, Jaime; Mayer, Ingrid A; Kelley, Mark C; Meszoely, Ingrid M; Means-Powell, Julie; Grau, Ana M; Sanders, Melinda; Bhave, Sandeep R; Yankeelov, Thomas E

2013-05-01

254

Design, methods and demographic findings of the DEMINVALL survey: a population-based study of Dementia in Valladolid, Northwestern Spain  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background This article describes the rationale and design of a population-based survey of dementia in Valladolid (northwestern Spain). The main aim of the study was to assess the epidemiology of dementia and its subtypes. Prevalence of anosognosia in dementia patients, nutritional status, diet characteristics, and determinants of non-diagnosed dementia in the community were studied. The main sociodemographic, educational, and general health status characteristics of the study population are described. Methods Cross-over and cohort, population-based study. A two-phase door-to-door study was performed. Both urban and rural environments were included. In phase 1 (February 2009 – February 2010) 28 trained physicians examined a population of 2,989 subjects (age: ? 65 years). The seven-minute screen neurocognitive battery was used. In phase 2 (May 2009 – May 2010) 4 neurologists, 1 geriatrician, and 3 neuropsychologists confirmed the diagnosis of dementia and subtype in patients screened positive by a structured neurological evaluation. Specific instruments to assess anosognosia, the nutritional status and diet characteristics were used. Of the initial sample, 2,170 subjects were evaluated (57% female, mean age 76.5?±?7.8, 5.2% institutionalized), whose characteristics are described. 227 persons were excluded for various reasons. Among those eligible were 592 non-responders. The attrition bias of non-responders was lower in rural areas. 241 screened positive (11.1%). Discussion The survey will explore some clinical, social and health related life-style variables of dementia. The population size and the diversification of social and educational backgrounds will contribute to a better knowledge of dementia in our environment.

Tola-Arribas Miguel Angel; Garea María José; Yugueros María Isabel; Ortega-Valín Fernando; Cerón Ana; Fernández-Malvido Beatriz; González-Touya Marta; San José Antonio; Botrán Ana; Iglesias Vanessa; Díaz-Gómez Bárbara

2012-01-01

255

Rapid Centroid Moment Tensor (CMT) Inversion in 3D Earth Structure Model for Earthquakes in Southern California  

Science.gov (United States)

Accurate and rapid CMT inversion is important for seismic hazard analysis. We have developed an algorithm for very rapid CMT inversions in a 3D Earth structure model and applied it on small to medium-sized earthquakes recorded by the Southern California Seismic Network (SCSN). Our CMT inversion algorithm is an integral component of the scattering-integral (SI) method for full-3D waveform tomography (F3DT). In the SI method for F3DT, the sensitivity (Fréchet) kernels are constructed through the temporal convolution between the earthquake wavefield (EWF) from the source and the receiver Green tensor (RGT) from the receiver. In this study, our RGTs were computed in a 3D seismic structure model for Southern California (CVM4SI1) using the finite-difference method, which allows us to account for 3D path effects in our source inversion. By storing the RGTs, synthetic seismograms for any source in our modeling volume could be generated rapidly by applying the reciprocity principle. An automated waveform-picking algorithm based on continuous wavelet transform is applied on observed waveforms to pick P, S and surface waves. A grid-searching algorithm is then applied on the picked waveforms to find an optimal focal mechanism that minimizes the amplitude misfit and maximize the weighted correlation coefficient. The grid-search result is then used as the initial solution in a gradient-based optimization algorithm that minimizes the L2 norm of the generalized seismological data functionals (GSDF), which quantifies waveform differences between observed and synthetic seismograms using frequencies-dependent phase-delay and amplitude anomalies. In general, our CMT solutions agree with solutions inverted using other methods and provide better fit to the observed waveforms.

Mu, D.; Lee, E.; Chen, P.; Jordan, T. H.; Maechling, P. J.

2010-12-01

256

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

International Nuclear Information System (INIS)

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

2001-01-01

257

Automatic NC-Data generation method for 5-axis cutting of turbine-blades by finding Safe heel-angles and adaptive path-intervals  

International Nuclear Information System (INIS)

In this paper, an efficient method for generating 5-axis cutting data for a turbine blade is presented. The interference elimination of 5-axis cutting currently is very complicated, and it takes up a lot of time. The proposed method can generate an interference-free tool path, within an allowance range. Generating the cutting data just point to the cutting process and using it to obtain NC data by calculating the feed rate, allows us to maintain the proper feed rate of the 5-axis machine. This paper includes the algorithms for: (1) CL data generation by detecting an interference-free heel angle, (2) finding the optimal tool path interval considering the cusp-height, (3) finding the adaptive feed rate values for each cutter path, and (4) the inverse kinematics depending on the structure of the 5-axis machine, for generating the NC data.

2004-01-01

258

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

Directory of Open Access Journals (Sweden)

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

Abdoljabbar Asadi; Azad Shojaei; Salar Saeidi; Salah Karimi; Ebad Karimi

2012-01-01

259

Interpreting regional myocardial magnetic resonance imaging data: A new method for collation with angiographic findings in patients with coronary artery disease  

International Nuclear Information System (INIS)

The magnetic resonance imaging (MRI) assessment of myocardial function and perfusion is a valuable complementary technique to coronary angiography. We describe a method of presenting and collating regional MRI data with the angiographic findings as annotated by the Green Lane reporting system. Routine clinical use of this approach is likely to increase the accuracy of MRI data interpretation and to influence both medical and interventional treatment strategies. Sensky, P.R. (2002).

2002-01-01

260

Interpreting regional myocardial magnetic resonance imaging data: A new method for collation with angiographic findings in patients with coronary artery disease  

Energy Technology Data Exchange (ETDEWEB)

The magnetic resonance imaging (MRI) assessment of myocardial function and perfusion is a valuable complementary technique to coronary angiography. We describe a method of presenting and collating regional MRI data with the angiographic findings as annotated by the Green Lane reporting system. Routine clinical use of this approach is likely to increase the accuracy of MRI data interpretation and to influence both medical and interventional treatment strategies. Sensky, P.R. (2002)

Sensky, Penelope R.; Hudson, Norah M.; Keal, Richard P.; Samani, Nilesh J.; Cherryman, Graham R

2002-06-01

 
 
 
 
261

Finding Factors  

Science.gov (United States)

This lesson is designed to develop students' abilities to find factors of whole numbers. The lesson also introduces prime numbers. This lesson provides links to discussions and activities related to factors as well as suggested ways to integrate them into the lesson. Finally, the lesson provides links to follow-up lessons designed for use in succession with the current one.

2010-01-01

262

Case management of individuals with long-term conditions by community matrons: report of qualitative findings of a mixed method evaluation.  

UK PubMed Central (United Kingdom)

Aim To consider findings from a study that evaluated case management of individuals with long-term conditions (LTCs) by a community matron (CM) service. The paper highlights issues related to the implementation of a new role and the impact this had on the experience of care across hospital and community settings for patients and their carers. BACKGROUND: The introduction of the role of CM was intended to increase effective management of patients with complex comorbid LTCs through the introduction of case management, thereby reducing unplanned hospital admissions. METHODS: The overall methodological approach was one of mixed methods. This paper reports the qualitative findings from CMs (n = 15); patients (n = 13); family carers (n = 8); and secondary care staff who interface with the CM service (n = 7). Data were collected between October 2009 and May 2010. Findings A thematic analysis resulted in the identification of four themes: (1) visibility; (2) interpersonal relationships; (3) leadership; and (4) systems/professional boundaries. Patients enjoyed being seen as a whole and family carers appreciated the coordination aspect of the role. Difficulties arose from the limited understanding of the CM role and from a lack of a shared vision across healthcare professionals concerning the role and its goals.

Randall S; Daly G; Thunhurst C; Mills N; Guest DA; Barker A

2013-02-01

263

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

264

Oscar — Using Byte Pairs to Find File Type and Camera Make of Data Fragments  

Science.gov (United States)

Mapping out the contents of fragmented storage media is hard if the file system has been corrupted, especially as the current forensic tools rely on meta information to do their job. If it was possible to find all fragments belonging to a certain file type, it would also be possible to recover a lost file. Such a tool could for example be used in the hunt for child pornography. The Oscar method identifies the file type of data fragments based solely on statistics calculated from their structure. The method does not need any meta data to work. We have previously used the byte frequency distribution and the rate of change between consecutive bytes as basis for the statistics, as well as calculating the 2-gram frequency distribution to create a model of different file types. This paper present a variant of the 2-gram method, in that it uses a dynamic smoothing factor. In this way we take the amount of data used to create the centroid into consideration. A previous experiment on file type identification is extended with .mp3 files reaching a detection rate of 76% with a false positives rate of 0.4%. We also use the method to identify the camera make used to capture a .jpg picture from a fragment of the picture. The result shows that we can clearly separate a picture fragment coming from a Fuji or Olympus cameras from a fragment of a picture of the other camera makes used in our test.

Karresand, Martin; Shahmehri, Nahid

265

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

CERN Multimedia

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

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

2002-01-01

266

Find It!  

Science.gov (United States)

In this activity students will learn the basic concept of Global Positioning Systems (GPS) using triangulation and measurement on a small scale in the classroom. Students discover how GPS and navigation integrate mathematic and scientific concepts to create a standard for locating people and objects. This activity helps students understand both the need for and methods of navigation. Pre-requisites: Students should have knowledge of measuring lengths and using a ruler.

Shah, Jay; Zarske, Malinda S.; Yowell, Janet

2006-01-01

267

California Pregnancy-Associated Mortality Review: Mixed Methods Approach for Improved Case Identification, Cause of Death Analyses and Translation of Findings.  

UK PubMed Central (United Kingdom)

After several decades of declining rates, maternal mortality climbed in California from a three-year moving average of 9.4 deaths per 100,000 live births in 1999-2001 to a high of 14.0 deaths per 100,000 live births in 2006-2008 (p < 0.001). The Maternal, Child and Adolescent Health Division of the California Department of Public Health developed a mixed method approach to identify and investigate maternal deaths to inform prevention strategies. This paper describes the methodology of the California Pregnancy-Associated Mortality Review (CA-PAMR) and its advantages for improved surveillance, cause of death analysis, and translation of findings. From 2002 to 2004, 1,598,792 live births occurred in California and 555 women died while pregnant or within one year of pregnancy. A screening algorithm identified cases for review that were likely to be pregnancy-related. Medical records were then abstracted and reviewed by a multidisciplinary committee to determine cause of death, contributing factors, and opportunities for quality improvement. Mixed methods were used to analyze, synthesize and translate Committee recommendations for improved care. Of 211 cases selected for review, 145 deaths were determined to be pregnancy-related. CA-PAMR methods corrected misclassification of cases and more accurately identified the leading causes of death. Cardiovascular disease emerged as the leading cause of pregnancy-related deaths (20 %), and African-American women were disproportionately represented among cardiovascular deaths. Overall, the chance to prevent the fatal outcome appeared good or strong in 40 % of cases reviewed. The CA-PAMR methodology resulted in additional case finding, improved accuracy of the causes of pregnancy-related deaths, and evidence to guide development of prevention and quality improvement efforts.

Mitchell C; Lawton E; Morton C; McCain C; Holtby S; Main E

2013-04-01

268

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)

[en] 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

2012-01-01

269

Using a simplex centroid to study the effects of pH, temperature and lactulose on the viability of Bifidobacterium animalis subsp. lactis in a model system.  

Science.gov (United States)

This paper reports on the effects of lactulose (0-10 g/l) on Bifidobacterium animalis subsp. lactis, along with the influence of pH (4.5-8.5) and temperature (15-45 °C); the three factors were combined through a simplex centroid. The experiments were performed in a laboratory medium and the data of cells counts were modeled through the Weibull equation for the evaluation of the first reduction time, the shape parameter and the death time. These fitting parameters were used as input values to build a desirability profile and a second-order model through the DoE approach (Design of Experiments). The medium containing glucose was used as control. The prebiotic enhanced the viability of the microbial target, by prolonging the first reduction time and inducing a shoulder phase in the death kinetic; moreover, in some combinations the statistical analysis highlighted a kind of interaction with the pH. PMID:23916721

Altieri, Clelia; Bevilacqua, Antonio; Perricone, Marianne; Sinigaglia, Milena

2013-07-31

270

Using a simplex centroid to study the effects of pH, temperature and lactulose on the viability of Bifidobacterium animalis subsp. lactis in a model system.  

UK PubMed Central (United Kingdom)

This paper reports on the effects of lactulose (0-10 g/l) on Bifidobacterium animalis subsp. lactis, along with the influence of pH (4.5-8.5) and temperature (15-45°C); the three factors were combined through a simplex centroid. The experiments were performed in a laboratory medium and the data of cells counts were modeled through the Weibull equation for the evaluation of the first reduction time, the shape parameter and the death time. These fitting parameters were used as input values to build a desirability profile and a second order model through the DoE approach (Design of Experiments). The medium containing glucose was used as control. The prebiotic enhanced the viability of the microbial target, by prolonging the first reduction time and inducing a shoulder phase in the death kinetic; moreover, in some combinations the statistical analysis highlighted a kind of interaction with the pH.

Altieri C; Bevilacqua A; Perricone M; Sinigaglia M

2013-07-01

271

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

UK PubMed Central (United Kingdom)

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.

Toge R; Morishita J; Sasaki Y; Doi K

2013-07-01

272

Feasibility, acceptability, and effects of gentle hatha yoga for women with major depression: findings from a randomized controlled mixed-methods study.  

UK PubMed Central (United Kingdom)

Major depressive disorder (MDD) is a common, debilitating chronic condition in the United States and worldwide. Particularly in women, depressive symptoms are often accompanied by high levels of stress and ruminations, or repetitive self-critical negative thinking. There is a research and clinical imperative to evaluate complementary therapies that are acceptable and feasible for women with depression and that target specific aspects of depression in women, such as ruminations. To begin to address this need, we conducted a randomized, controlled, mixed-methods community-based study comparing an 8-week yoga intervention with an attention-control activity in 27 women with MDD. After controlling for baseline stress, there was a decrease in depression over time in both the yoga group and the attention-control group, with the yoga group having a unique trend in decreased ruminations. Participants in the yoga group reported experiencing increased connectedness and gaining a coping strategy through yoga. The findings provide support for future large scale research to explore the effects of yoga for depressed women and the unique role of yoga in decreasing rumination.

Kinser PA; Bourguignon C; Whaley D; Hauenstein E; Taylor AG

2013-06-01

273

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

International Nuclear Information System (INIS)

[en] 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

1982-01-01

274

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.

Zoellner Jamie M; Connell Carol C; Madson Michael B; Wang Bo; Reed Vickie; Molaison Elaine; Yadrick Kathleen

2011-01-01

275

Finding the plug  

Energy Technology Data Exchange (ETDEWEB)

A pressure pulse through a pipeline can locate plugs, saving oil companies a lot of money. More and more oil extraction takes place on the ocean floor - not the easiest place to reach when it comes to maintaining and repairing pipelines that do not function the way they should. Researchers at the Norwegian University of Science and Technology have developed and patented a new technique called the pressure pulse method for finding plugs in oil pipelines on the ocean floor. (AG)

Oksholen, Tore

2009-07-01

276

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

A survey on farmer`s pest control methods and direct yield loss assessment of country bean (Dolichos lablab) was done during September 2000 to February 2001 in North Edilpur and South Mohadebpur villages of Sitakundu under Chittagong district. Results revealed that farmers used Fanfan, Nogos,...

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

277

Finding of experience of the use of computer-integrated forms and methods of teaching in the process of preparation of future teachers of initial school  

Directory of Open Access Journals (Sweden)

Full Text Available Theoretically grounded and experimentally examined that one of the trends of future teachers training for the integrated activity is gaining experience in using the integrated organization forms of learning. It is realized in the process of specially organized student's learning and during their pedagogical practice. It was promoted by conducting the special course The integrated forms of learning organization in primary school with the use of interactive forms and methods of learning, fulfilling the aimed tasks while passing pedagogical practice.

Sinopalnikova N.N.

2010-01-01

278

Return to work among employees with common mental disorders: study design and baseline findings from a mixed-method follow-up study.  

UK PubMed Central (United Kingdom)

AIMS: Most research on return-to-work (RTW) has focused on musculoskeletal disorders. To study RTW in employees sick-listed with common mental disorders (CMD), e.g., stress, depression, and anxiety, the National Research Centre for the Working Environment initiated a study on ''Common Mental Disorders, Return-to-work, and Long-term Sickness Absence'' (CORSA). The aim of the study is (1) to identify predictors of RTW from the environmental, the individual, and the health-related domain and (2) to explore the RTW process based on study participants' experiences. The purpose of this paper is to present the study design and the characteristics of the participants, including analyses on non-response and the prevalence of major depression. METHODS: CORSA is a mixed-method follow-up study encompassing quantitative and qualitative analyses in a cohort of employees sick-listed with CMD. Participants were all employees who suffered from CMD and whose applications for sickness absence benefits were processed by the Job Centre Copenhagen (a subunit of the municipality) between July and December 2007 (n = 721). Data on predictors for RTW were collected from (1) administrative application forms filled out by all participants when applying for benefits (n = 721), and (2) baseline questionnaires sent to all participants (responders: n = 298). Data on RTW was retrieved from a national sickness absence registry and from 6-month follow-up questionnaires (n = 226). To explore the RTW process we will primarily use data from in-depth interviews with selected participants (n = 16) supplemented with data from the two questionnaires. CONCLUSIONS: The mixed method design allows for a more comprehensive understanding of RTW by triangulating qualitative and quantitative methods.

Nielsen MB; Bültmann U; Amby M; Christensen U; Diderichsen F; Rugulies R

2010-12-01

279

'Finding a good thing': the use of quantitative and qualitative methods to evaluate an exercise class and promote exercise for adults with mobility impairments.  

UK PubMed Central (United Kingdom)

PURPOSE: Physical inactivity in people with severe disabilities is common and has severe consequences. Conditioning classes are one way to increase activity and promote its health related outcomes. This paper reports the results of an evaluation of a community based conditioning class for adults with mobility impairments. METHOD: The study uses two methods with two samples: a quantitative self-report methodology and a quantitative interview. RESULTS: The quantitative evaluation found no significant increases in standard self-report measures of physical activity, functional status, quality of life, depression, or exercise self-efficacy. The lack of significant quantitative results may be due to limits in study design. The open-ended qualitative interviews with 16 class participants show important physical, social and psychological improvements. The juxtaposition of these two perspectives allows researchers to recognize the limitations in their choice of methods and the challenges faced by researchers evaluating small community based programmes for this limited population. CONCLUSION: In this case, the qualitative evaluation captured the positive experiences of the exercise class participants.

Maher EJ; Kinne S; Patrick DL

1999-09-01

280

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.

Gayle E. Reiber, MPH, PhD; Lynne V. McFarland, PhD; Sharon Hubbard, MS; Charles Maynard, PhD; David K. Blough, PhD; Jeffrey M. Gambel, MD, MPH, MSW; Douglas G. Smith, MD

2010-01-01

 
 
 
 
281

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

UK PubMed Central (United Kingdom)

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%), hearing loss (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 rehabilitation for those with limb loss and several areas for future attention.

Reiber GE; McFarland LV; Hubbard S; Maynard C; Blough DK; Gambel JM; Smith DG

2010-01-01

282

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

2008-01-01

283

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

Directory of Open Access Journals (Sweden)

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

Snooks Helen A; Evans Bridie; Cohen David; Nugent Michael; Rapport Frances; Skone Jon; Meredith Angie; Davies Tricia; O'Sullivan Diana

2011-01-01

284

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.

Gonda Xenia; Fountoulakis Konstantinos N; Rihmer Zoltan; Laszik Andras; Akiskal Hagop S; Bagdy Gyorgy

2010-01-01

285

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.

Kristalina Prima; Wirawan; Gamantyo Hendrantoro

2011-01-01

286

Chilaiditi syndrome: sonographic findings.  

UK PubMed Central (United Kingdom)

BACKGROUND AND METHODS: Sonographic (US) findings of Chilaiditi syndrome have been rarely reported in the literature. We reviewed 18 cases of Chilaiditi syndrome to pinpoint its US pattern. RESULTS: (1) US showed gas echoes of different sizes superimposed over the entire liver in two cases and over the right hepatic lobe in six cases, leading to a high suspicion of Chilaiditi syndrome. (2) US showed a small gas echo in the hepatodiaphragmatic space, mimicking pneumoperitoneum in eight cases. In this instance, altering the patient's position allowed for confirmation of the lack of a change in the location of the gas echo, unlike cases of pneumoperitoneum. (3) The hepatic surface appeared as a hyperechoic mass in two cases. CONCLUSION: Knowledge of US patterns of Chilaiditi syndrome helps avoid confusion with pneumoperitoneum or hepatic masses.

Sato M; Ishida H; Konno K; Hamashima Y; Naganuma H; Komatsuda T; Ishida J; Watanabe S

2000-07-01

287

Finding Cryptography in Object Code  

Energy Technology Data Exchange (ETDEWEB)

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

Jason L. Wright

2008-10-01

288

Characterization of uncertainty in the classification of multivariate assays: application to PAM50 centroid-based genomic predictors for breast cancer treatment plans  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Multivariate assays (MVAs) for assisting clinical decisions are becoming commonly available, but due to complexity, are often considered a high-risk approach. A key concern is that uncertainty on the assay's final results is not well understood. This study focuses on developing a process to characterize error introduced in the MVA's results from the intrinsic error in the laboratory process: sample preparation and measurement of the contributing factors, such as gene expression. Methods Using the PAM50 Breast Cancer Intrinsic Classifier, we show how to characterize error within an MVA, and how these errors may affect results reported to clinicians. First we estimated the error distribution for measured factors within the PAM50 assay by performing repeated measures on four archetypal samples representative of the major breast cancer tumor subtypes. Then, using the error distributions and the original archetypal sample data, we used Monte Carlo simulations to generate a sufficient number of simulated samples. The effect of these errors on the PAM50 tumor subtype classification was estimated by measuring subtype reproducibility after classifying all simulated samples. Subtype reproducibility was measured as the percentage of simulated samples classified identically to the parent sample. The simulation was thereafter repeated on a large, independent data set of samples from the GEICAM 9906 clinical trial. Simulated samples from the GEICAM sample set were used to explore a more realistic scenario where, unlike archetypal samples, many samples are not easily classified. Results All simulated samples derived from the archetypal samples were classified identically to the parent sample. Subtypes for simulated samples from the GEICAM set were also highly reproducible, but there were a non-negligible number of samples that exhibit significant variability in their classification. Conclusions We have developed a general methodology to estimate the effects of intrinsic errors within MVAs. We have applied the method to the PAM50 assay, showing that the PAM50 results are resilient to intrinsic errors within the assay, but also finding that in non-archetypal samples, experimental errors can lead to quite different classification of a tumor. Finally we propose a way to provide the uncertainty information in a usable way for clinicians.

Ebbert Mark TW; Bastien Roy RL; Boucher Kenneth M; Martín Miguel; Carrasco Eva; Caballero Rosalía; Stijleman Inge J; Bernard Philip S; Facelli Julio C

2011-01-01

289

Characterization of uncertainty in the classification of multivariate assays: application to PAM50 centroid-based genomic predictors for breast cancer treatment plans.  

UK PubMed Central (United Kingdom)

BACKGROUND: Multivariate assays (MVAs) for assisting clinical decisions are becoming commonly available, but due to complexity, are often considered a high-risk approach. A key concern is that uncertainty on the assay's final results is not well understood. This study focuses on developing a process to characterize error introduced in the MVA's results from the intrinsic error in the laboratory process: sample preparation and measurement of the contributing factors, such as gene expression. METHODS: Using the PAM50 Breast Cancer Intrinsic Classifier, we show how to characterize error within an MVA, and how these errors may affect results reported to clinicians. First we estimated the error distribution for measured factors within the PAM50 assay by performing repeated measures on four archetypal samples representative of the major breast cancer tumor subtypes. Then, using the error distributions and the original archetypal sample data, we used Monte Carlo simulations to generate a sufficient number of simulated samples. The effect of these errors on the PAM50 tumor subtype classification was estimated by measuring subtype reproducibility after classifying all simulated samples. Subtype reproducibility was measured as the percentage of simulated samples classified identically to the parent sample. The simulation was thereafter repeated on a large, independent data set of samples from the GEICAM 9906 clinical trial. Simulated samples from the GEICAM sample set were used to explore a more realistic scenario where, unlike archetypal samples, many samples are not easily classified. RESULTS: All simulated samples derived from the archetypal samples were classified identically to the parent sample. Subtypes for simulated samples from the GEICAM set were also highly reproducible, but there were a non-negligible number of samples that exhibit significant variability in their classification. CONCLUSIONS: We have developed a general methodology to estimate the effects of intrinsic errors within MVAs. We have applied the method to the PAM50 assay, showing that the PAM50 results are resilient to intrinsic errors within the assay, but also finding that in non-archetypal samples, experimental errors can lead to quite different classification of a tumor. Finally we propose a way to provide the uncertainty information in a usable way for clinicians.

Ebbert MT; Bastien RR; Boucher KM; Martín M; Carrasco E; Caballero R; Stijleman IJ; Bernard PS; Facelli JC

2011-01-01

290

A simple and robust method to extend the dynamic range of an aberrometer.  

UK PubMed Central (United Kingdom)

We present an algorithm to extend significantly the dynamic range of a Shack-Hartmann wavefront sensor. With this method, the recorded Shack-Hartmann spots are not constrained to stay in the field of view of their lenslet. The proposed algorithm is computationally effective, robust to a high level of noise on the measured centroid positions and also to missing centroid values. The principle is closely related to the description of wavefronts using Zernike polynomials, which makes optimization for a given sensor and application achievable thanks to numerical simulation. These features make it useful for the measurements of highly aberrated eyes.

Leroux C; Dainty C

2009-10-01

291

Finding a Neurosurgeon  

Science.gov (United States)

Tip: Finding A Neurosurgeon The first step in getting proper treatment for Chiari is to find the right doctor. While many patients are referred first to a neurologist, given that the only real treatment for Chiari ...

292

Find an Oncologist  

Science.gov (United States)

Find an Oncologist Database The Find an Oncologist Database is made available by ASCO as a resource for informational purposes. The database includes the names of physicians and other health professionals ...

293

Dermoscopic findings of pilomatricomas.  

UK PubMed Central (United Kingdom)

BACKGROUND: To the best of our knowledge, no specific dermoscopic criteria have been described in the medical literature for the diagnosis of pilomatricomas. OBJECTIVES: To evaluate the morphological findings of pilomatricomas under dermoscopic observation. MATERIAL AND METHODS: Dermoscopic examination (using the Dermlite Foto; 3Gen, LLC, Dana Point, Calif., USA) of 10 patients with pilomatricomas was performed to evaluate specific dermoscopic criteria and patterns. RESULTS: The most frequently occurring dermoscopic features were found to be: irregular white structures (80%) and white streaks (70%); vascular structures in all lesions (reddish homogeneous area in 90%, hairpin vessels in 70%, linear-irregular vessels in 70% and dotted vessels in 40%); ulceration (60%), and structureless gray-blue areas in 20% of cases. The results of our study reveal that the absence of specific dermoscopic criteria for other skin tumors and the presence of irregular white structures and polymorphous/atypical vessels is the most frequent dermoscopic pattern in pilomatricomas. CONCLUSIONS: Dermoscopy may be a useful tool for improving the recognition of pilomatricomas. However, dermoscopy does not assure 100% diagnostic accuracy and pilomatricomas may represent in some cases, above all in elderly patients, a dermoscopic pitfall, being difficult to differentiate dermoscopically from other lesions, such as melanoma or basal cell carcinoma.

Zaballos P; Llambrich A; Puig S; Malvehy J

2008-01-01

294

[Neurobiological findings in schizophrenia].  

UK PubMed Central (United Kingdom)

BACKGROUND: Schizophrenia is a syndrome with important neurobiological abnormalities which have not yet been fully clarified and whose aetiology is poorly understood. MATERIAL AND METHODS: The paper gives a survey of the most important neurobiological abnormalities found in schizophrenia, based on relevant research publications, mainly from the most recent decades. RESULTS AND INTERPRETATIONS: Pathomorphological findings in schizophrenia include ventricular and cortical sulcal enlargement, reduction of cortical thickness, cellular changes with reduction of dendrites and synapses, presumably resulting in reduced cortico-cortical and cortico-subcortical connections. These abnormalities are thought to be mainly developmental in origin, mostly on a genetic basis, but also with varying contributions from prenatal or perinatal damage. In a subgroup of schizophrenics there is a poorly understood neurodegenerative process going on also after the debut of the psychosis. Neurochemically, interest has focused mostly on dopaminergic dysfunction, but other transmitters like serotonin, glutamate and GABA are also involved, as is probably the neurotensin peptide. There is also increasing evidence of disturbed cell membrane composition and function in schizophrenia, especially with regard to polyunsaturated fatty acids.

Lingjaerde O

2002-09-01

295

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.

Hanigan Ivan; Hall Gillian; Dear Keith BG

2006-01-01

296

Performance analysis of k-means with different initialization methods for high dimensional data  

Directory of Open Access Journals (Sweden)

Full Text Available Developing effective clustering method for high dimensional dataset is a challengingproblem due to the curse of dimensionality. Among all the partition based clusteringalgorithms, k-means is one of the most well known methods to partition a dataset intogroups of patterns. However, the k-means method converges to one of many localminima. And it is known that, the final result depends on the initial starting points(means). Many methods have been proposed to improve the performance of k-meansalgorithm. In this paper, we have analyzed the performance of our proposed method withthe existing works. In our proposed method, we have used Principal Component Analysis(PCA) for dimension reduction and to find the initial centroid for k-means. Next we haveused heuristics approach to reduce the number of distance calculation to assign the datapoint to cluster. By comparing the results on iris data set, it was found that the resultsobtained by the proposed method are more effective than the existing method.

Tajunisha; Saravanan

2010-01-01

297

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

298

Retinal findings in Takayasu's arteritis.  

UK PubMed Central (United Kingdom)

PURPOSE: To describe unusual as well as typical ocular findings in eight patients with Takayasu's disease. METHODS: The ophthalmic manifestations and clinical courses of eight patients with Takayasu's disease were evaluated. RESULTS: All patients had clinical and angiographic evidence of pulseless disease. Typical findings included retinal venous congestion, fluorescein staining, capillary drop-out, microaneurysms and arteriovenous shunting. Unusual findings included cotton wool spots, anterior ischemic neuropathy and retinal emboli. In one case microaneurysms disappeared after carotid bypass surgery. Several patients had profound, transient, visual loss with changes in head posture. CONCLUSION: Takayasu's disease can cause a variety of retinal manifestations. Less common findings include cotton wool spots, anterior ischemic optic neuropathy and retinal emboli.

Karam EZ; Muci-Mendoza R; Hedges TR 3rd

1999-04-01

299

METHOD  

UK PubMed Central (United Kingdom)

The present invention provides methods and uses for treating pyropheophytin-containing compositions, particularly in order to remove pyropheophytin therefrom. The compositions are typically plant, algal, or bacterial derived products such as vegetable oils. The method comprises a step of contacting the compositions with an enzyme having pyropheophytinase activity. Also provided are related apparatus and products for performing such methods and uses.

SOEE JOERN BORCH; POULSEN CHARLOTTE HORSMANS; ZARGAHI MASOUD RAJABI; SOERENSEN JENS FRISBAEK; JOERGENSEN TINA; BRUNSTEDT JANNE; MIKKELSEN RENE; MADRID SUSAN MAMPUSTI

300

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

 
 
 
 
301

A modified semi-supervised color image segmentation method  

Directory of Open Access Journals (Sweden)

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

Wei Hongru; Chai Fangyong

2012-01-01

302

Ophthalmologic findings in Aicardi syndrome.  

UK PubMed Central (United Kingdom)

BACKGROUND: Aicardi syndrome is a rare X-linked disorder that has been characterized classically by agenesis of the corpus callosum, seizures, and the finding of chorioretinal lacunae. This triad has been augmented more recently by central nervous system and ocular findings. The goal of this study was to determine how frequently other ophthalmologic findings are associated with Aicardi syndrome. METHODS: A single ophthalmologist recorded the ocular and adnexal findings of 40 girls with this disorder at the annual meeting of an Aicardi syndrome family support group. For each subject, the examiner performed facial anthropometrics, portable biomicroscopy, and, where feasible, indirect ophthalmoscopy. RESULTS: The most common findings were chorioretinal lacunae in 66 (88%) of 75 eyes and optic nerve abnormalities in 61 (81%) of 75 eyes. Other less common findings included persistent pupillary membrane in 4 (5%) of 79 eyes and anterior synechiae in 1 of 79 eyes (1%). CONCLUSIONS: Although the ophthalmic hallmark and defining feature of Aicardi syndrome is the cluster of distinctive chorioretinal lacunae surrounding the optic nerve(s), the spectrum of ocular, papillary, and retinal anomalies varies widely, from nearly normal to dysplasia of the optic nerve and to severe microphthalmos.

Fruhman G; Eble TN; Gambhir N; Sutton VR; Van den Veyver IB; Lewis RA

2012-06-01

303

Find a Blood Establishment  

Science.gov (United States)

... Find a Blood Establishment. Welcome to the eBER Public Query application. You may use this application to review blood ... More results from www.fda.gov/biologicsbloodvaccines/guidancecomplianceregulatoryinformation/establishmentregistration

304

Find an Endocrinologist  

Science.gov (United States)

... Careers AACE Mailing Lists AACE Endo Source Join AACE Apply for AACE Membership today using our easy ... scientific, educational and charitable medical organization ABOUT AACE AACE Find an Endocrinologist City/State/Country Search Note: ...

305

Find a Cancer Center  

Science.gov (United States)

Find the locations of NCI-designated cancer centers by area, region, state, or name that includes contact information to help health care providers and cancer patients with referrals to clinical trials.

306

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,

307

Sylfiden findes : en svævebog  

DEFF Research Database (Denmark)

Sylfiden findes. Men hvordan kan sylfiden findes - og bare være en drøm? Denne ’svævebog’ fortolker længslen i Bournonvilles internationale ballethit - gennem nye fotos af katastrofefotografen Jan Grarup samt fortolkende svæveessays, meddigtende flakserier, en sylfidescrapbog med anmeldelser af balletdansere i hovedpartierne i Sylfiden fra 1836 til 2008, et sylfideleksikon og sylfideord for børn. En videnskabelig bog, formidlet for både ballethistorikeren, balletelskeren, balletbegynderen og romantikdyrkeren. Resumé på engelsk, fransk, spansk og russisk.

Christensen, Anne Middelboe

2008-01-01

308

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

309

METHOD  

UK PubMed Central (United Kingdom)

The present invention provides a method of selectively activating and/or targeting stem cells which enables the cells to then be manipulated mechanically in a remote manner wherein the method comprises magnetically manipulating a stem cell in vivo or in vitro by the association of a magnetisable particle within the stem cell.

DOBSON JON; EL HAJ ALICIA

310

CT findings of colonic diverticulitis  

International Nuclear Information System (INIS)

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

1998-01-01

311

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

312

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

313

Radiologic findings of emphysematous pyelonephritis  

International Nuclear Information System (INIS)

[en] 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

1995-01-01

314

Imaging findings in pleuropulmonary blastoma  

International Nuclear Information System (INIS)

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.)

2005-01-01

315

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

316

Finding Initial Parameters of Neural Network for Data Clustering  

Directory of Open Access Journals (Sweden)

Full Text Available K-means fast learning artificial neural network (K-FLANN) algorithm begins with the initialization oftwoparameters vigilance and tolerance which are the key to get optimal clustering outcome. The optimizationtask is to change these parameters so a desired mapping between inputs and outputs (clusters) of the K-FLANN is achieved. This study presents finding thebehavioral parameters of K-FLANN that yield goodclustering performance using an optimization methodknown as Differential Evolution. DE algorithm is asimple efficient meta-heuristic for global optimization over continuous spaces. The K-FLANN algorithmismodified to select winning neuron (centroid) for adata member in order to improve the matching rate frominput to output. The experiments were performed toevaluate the proposed work using machine learningartificial data sets for classification problems and synthetic data sets. The simulation results haverevealedthat optimization of K-FLANN has given quite promising results in terms of convergence rate and accuracywhen compared with other algorithms. Also the comparisons are made between K-FLANN and modified K-FLANN.

Suneetha Chittineni; Raveendra Babu Bhogapathi

2013-01-01

317

CT findings of ganglioneuroma  

International Nuclear Information System (INIS)

Ganglioneuroma is a relatively uncommon benign tumor and has no pathognomonic radiological findings;diagnosis is therefore difficult. In order to better diagnose this tumor we analysed its CT findings and pathologic correlation. Seventeen tumors in 16 patients(M:F=3D9:7) diagnosed as ganglioneuroma between 1992 and 1996 were retrospectively analysed with regard to location, size, contour, long axis of the mass, enhancement pattern, calcification, necrosis and capsulation, all as seen on CT, and compared with histo-pathologic findings. Tumors were 1.5 to 10(mean, 5.6) cm in size, and their location was mediastinal(n=3D12), cervical(n=3D2), retroperitoneal (n=3D2) or adrenal(n=3D1). Fifteen had an oval or round contour and two were dumb-bell-shaped. The long axis of the lesion was craniocaudal in 14 cases and non-specific in three. Thirteen lesions showed heterogeneous enhancement, and four homogeneous. Capsule-like enhancement was noted on CT scans in eight cases;there was no definite correlation between enhancement pattern and pathologic findings. Calcification was seen in six cases and an inner low-density lesion in two. Ganglioneuroma is a benign neurogenic tumor, occurring most frequently at the posterior mediastinum. General CT findings of this tumor are a well-defined oval shape with a variable enhancement pattern, but several cases showed focal calcification or inner low density. For accurate diagnosis of ganglioneuroma both common and uncommon findings must therefore be considered.=20

1998-01-01

318

Finding biomedical categories in Medline®  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background There are several humanly defined ontologies relevant to Medline. However, Medline is a fast growing collection of biomedical documents which creates difficulties in updating and expanding these humanly defined ontologies. Automatically identifying meaningful categories of entities in a large text corpus is useful for information extraction, construction of machine learning features, and development of semantic representations. In this paper we describe and compare two methods for automatically learning meaningful biomedical categories in Medline. The first approach is a simple statistical method that uses part-of-speech and frequency information to extract a list of frequent nouns from Medline. The second method implements an alignment-based technique to learn frequent generic patterns that indicate a hyponymy/hypernymy relationship between a pair of noun phrases. We then apply these patterns to Medline to collect frequent hypernyms as potential biomedical categories. Results We study and compare these two alternative sets of terms to identify semantic categories in Medline. We find that both approaches produce reasonable terms as potential categories. We also find that there is a significant agreement between the two sets of terms. The overlap between the two methods improves our confidence regarding categories predicted by these independent methods. Conclusions This study is an initial attempt to extract categories that are discussed in Medline. Rather than imposing external ontologies on Medline, our methods allow categories to emerge from the text.

Yeganova Lana; Kim Won; Comeau Donald C; Wilbur W John

2012-01-01

319

Dawn: Find a Meteorite  

Science.gov (United States)

This activity introduces the importance of meteorites to the understanding of the origin of the Solar System. Finding meteorites can be difficult because most meteorites look like Earth rocks to the casual or untrained eye. Even to the trained eye, recognizing meteorites can be difficult. Since scientists believe that some meteorites are pieces of the asteroid Vesta, they may be very old remnants of the Solar System in its earliest stages. This activity provides information and insight that allows participants to share scientists' expectations, based on meteoritic samples, of what we will find when the NASA's Dawn Mission visits Vesta and Ceres.

Risvey, John

2005-01-01

320

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

 
 
 
 
321

Vertebral sarcoidosis: imaging findings  

Energy Technology Data Exchange (ETDEWEB)

Sarcoidosis is a multisystemic disease of unknown aetiology characterised by noncaseating granulomatous inflammation with varying presentation and prognosis. Osseous disease reported in 1-13 % of cases commonly involves hands and feet; however, vertebral sarcoidosis is rare. This report describes the radiologic, CT, MRI and radionuclide imaging findings of vertebral involvement of a case with sarcoidosis. (orig.)

Poyanli, A.; Sencer, S.; Acunas, B. [Dept. of Radiology, Istanbul Medical Faculty, Istanbul (Turkey); Poyanli, O.; Akan, K. [Department of Orthopaedics and Traumatology, Goeztepe SSK Educational Hospital, Istanbul (Turkey); Sayrak, H. [Department of Pathology, Goeztepe SSK Educational Hospital, Istanbul (Turkey)

2000-01-01

322

Poland's syndrome: radiologic findings  

International Nuclear Information System (INIS)

[en] Poland's syndrome is a rare non-inherited congenital anomaly. The authors describe the classic radiologic findings of Poland's syndrome by reporting the case of a male four-year old patient with asymmetry of hands and chest, illustrating the fundamental imaging criteria for a conclusive diagnosis. (author)

2012-01-01

323

Find a Healthcare Professional  

Science.gov (United States)

... 8.227512|||Emil Chuang, M.D.|||||||||||||||||||||, Gastroenterology|||Physician|||Nestlé Health Science||||||http://www.ccfa.org/living-with- ... find-a-doctor/Emil-Chuang.html|||Avenue 55 Nestle REL2 3-24 1800, Vevey Switzerland 336724352|||41. ...

324

Ct findings of enteric fistula  

Energy Technology Data Exchange (ETDEWEB)

Enteric fistulae result from gastrointestinal perforations in which communication is established between the site of perforation and another hollow viscus, potential space, or skin surface. Certain types of enteric fistulae are difficult to demonstrate by conventional radiographic methods, and CT is unique in its ability to demonstrate the extent and nature of extraluminal changes. The purpose of this study is to illustrate the CT findings of enteric fistulae occurring in a variety of abdominal and pelvic organs. (author). 5 refs., 10 figs.

Hwang, Jae Cheol; Ha, Hyun Kwon; Weon, Young Cheol; Lee, Moon Gyu; Kim, Pyo Nyun; Auh, Yong Ho [Asan Medical Center, Seoul (Korea, Republic of)

1997-12-01

325

Ct findings of enteric fistula  

International Nuclear Information System (INIS)

Enteric fistulae result from gastrointestinal perforations in which communication is established between the site of perforation and another hollow viscus, potential space, or skin surface. Certain types of enteric fistulae are difficult to demonstrate by conventional radiographic methods, and CT is unique in its ability to demonstrate the extent and nature of extraluminal changes. The purpose of this study is to illustrate the CT findings of enteric fistulae occurring in a variety of abdominal and pelvic organs. (author). 5 refs., 10 figs.

1997-01-01

326

Radiological findings of clonorchiasis  

Energy Technology Data Exchange (ETDEWEB)

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.

Kang, I. W.; Seo, H. S.; Lim, D. R.; Yeon, K. M. [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1980-06-15

327

[Imaging findings in neurocysticercosis].  

UK PubMed Central (United Kingdom)

Neurocysticercosis, caused by the larvae of Taenia solium, is the parasitic infection that most commonly involves the central nervous system in humans. Neurocysticercosis is endemic in practically all developing countries, and owing to globalization and immigration it is becoming more common in developed countries like those in western Europe. The most common clinical manifestations are epilepsy, focal neurologic signs, and intracranial hypertension. The imaging findings depend on the larval stage of Taenia solium, on the number and location of the parasites (parenchymal, subarachnoid, or intraventricular), as well as on the host's immune response (edema, gliosis, arachnoiditis) and on the development of secondary lesions (arteritis, infarcts, or hydrocephalus). The diagnosis of this parasitosis must be established on the basis of the clinical and radiological findings, especially in the appropriate epidemiological context, with the help of serological tests.

Sarria Estrada S; Frascheri Verzelli L; Siurana Montilva S; Auger Acosta C; Rovira Cañellas A

2013-03-01

328

[Imaging findings in neurocysticercosis].  

Science.gov (United States)

Neurocysticercosis, caused by the larvae of Taenia solium, is the parasitic infection that most commonly involves the central nervous system in humans. Neurocysticercosis is endemic in practically all developing countries, and owing to globalization and immigration it is becoming more common in developed countries like those in western Europe. The most common clinical manifestations are epilepsy, focal neurologic signs, and intracranial hypertension. The imaging findings depend on the larval stage of Taenia solium, on the number and location of the parasites (parenchymal, subarachnoid, or intraventricular), as well as on the host's immune response (edema, gliosis, arachnoiditis) and on the development of secondary lesions (arteritis, infarcts, or hydrocephalus). The diagnosis of this parasitosis must be established on the basis of the clinical and radiological findings, especially in the appropriate epidemiological context, with the help of serological tests. PMID:22632836

Sarria Estrada, S; Frascheri Verzelli, L; Siurana Montilva, S; Auger Acosta, C; Rovira Cañellas, A

2012-05-26

329

BIOMOD - preliminary findings  

International Nuclear Information System (INIS)

Certain preliminary findings on the workings of the biosphere code BIOMOD are presented. These are intended as the basis for technical discussions relating to the development of BIOMOD1. Discussion is restricted to observations on the relationships between user-defined input and i) relative significance of different pathways for activity transfer to man, ii) total activity consumption by man, and iii) activity released to dose conversion factors to be used in SYVAC. (author)

1983-01-01

330

Heterotopic pregnancy: Sonographic findings  

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-03-15

331

Heterotopic pregnancy: Sonographic findings  

International Nuclear Information System (INIS)

[en] 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.

1999-01-01

332

MR findings of polymyositis / dermatomyositis  

International Nuclear Information System (INIS)

The purpose of this study was to evaluate the MR findings and useful sequences in Polymyositis/ Dermatomyositis, and to correlate MR findings with disease activity. Materials and Methods: The study included nine clinically proven cases of Polymyositis/Dermatomyositis, eight involving the thigh and one, the shoulder (2 cases, 1 follow-up). The contrast between affected and normal muscles and difference in signal intensity ratio in the muscle groups were retrospectively evaluated on Gd-enhanced T1WI and T2WI. We also evaluated the magnitude of involvement of muscle groups, fatty replacement of muscle and change of subcutaneous fat layer, and correlated signal intensity ratio with serum level of muscle enzymes. Differences in signal intensity ratio and the frequency of chemical shift artifact were evaluated on T2WI as active and inactive groups classified according to clinical findings, and the chemical shift artifact was correlated with the finding of Gd-enhanced T1WI. Except in the case of one shoulder, statistical analysis was assessed by the Anova test and-test. Results: On Gd-enhanced T1WI and T2WI contrast was 0.54 and 0.82, respectively and p value was 0.02. With regard to difference in signal intensity ratios of muscle groups, as seen on Gd-enhanced T1WI and T2WI, p valves were 0.07 and

1998-01-01

333

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.)

1999-01-01

334

Imaging findings of tarsal chondroblastoma  

International Nuclear Information System (INIS)

Objective: To analysis the imaging features of the chondroblastoma in the tarsal bone. Methods: The locations of 134 cases of pathologically confirmed chondroblastoma were retrospectively analyzed. Eleven of them were in tarsal bones and their X-ray and CT findings were analyzed. Results: Of the 11 cases of tarsal chondroblastoma, 6 were in talus, 3 were in calcaneus and 2 cases were in navicular bones. They were examined by the X-ray and 5 cases had additional CT scans. The common locations were the posterior portion of the talus and calcaneus. The X-ray findings included expansive destruction (10/11), mild osteosclerosis (11/11), bone ridge (9/11), articular facet destruction (7/11) and spot or patching calcification (6/11). The imaging findings of CT included articular facets destruction (5/5), bone ridge (5/5) and spot or patching calcification (2/5). Conclusion: The talus and the calcaneus are the frequently involved location of tarsal chondroblastoma. Its X-ray and CT findings are characteristic but not exclusive. (authors)

2010-01-01

335

MR findings of ulegyria  

International Nuclear Information System (INIS)

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

1991-01-01

336

[Acute appendicitis, echographic findings  

UK PubMed Central (United Kingdom)

A case of acute appendicitis in which an appendicolith was present is described. The diagnosis was made by plain abdominal radiography and ultrasound, and was confirmed at surgery. The plain abdominal film showed a lamellated, round calcification, projecting over the right iliac wing. Ultrasound revealed a tubular, hypoechogenic structure, containing an oval hyperechogenic area with acoustic shadow. The recent literature was reviewed, and the "graded compression" technique is described. A summary is given of the ultrasound findings of acute appendicitis, and of its most important differential diagnoses in childhood: mesenterial adenitis, and--less frequently--terminal ileitis.

Baeyaert M

1989-02-01

337

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).

1994-01-01

338

Find-It! Consumer  

Science.gov (United States)

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

339

Ultrasonographic findings of Epicondylitis  

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-09-15

340

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.

2002-01-01

 
 
 
 
341

Finding Optimal Flows Efficiently  

CERN Multimedia

Among the models of quantum computation, the One-way Quantum Computer is one of the most promising proposals of physical realization, and opens new perspectives for parallelization by taking advantage of quantum entanglement. Since a one-way quantum computation is based on quantum measurement, which is a fundamentally nondeterministic evolution, a sufficient condition of global determinism has been introduced as the existence of a causal flow in a graph that underlies the computation. A O(n^3)-algorithm has been introduced for finding such a causal flow when the numbers of output and input vertices in the graph are equal, otherwise no polynomial time algorithm was known for deciding whether a graph has a causal flow or not. Our main contribution is to introduce a O(n^2)-algorithm for finding a causal flow, if any, whatever the numbers of input and output vertices are. This answers the open question stated by Danos and Kashefi and by de Beaudrap. Moreover, we prove that our algorithm produces an optimal flow (...

Mhalla, Mehdi

2007-01-01

342

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

1993-01-01

343

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

344

MRI findings in neuroferritinopathy.  

Science.gov (United States)

Neuroferritinopathy is a neurodegenerative disease which demonstrates brain iron accumulation caused by the mutations in the ferritin light chain gene. On brain MRI in neuroferritinopathy, iron deposits are observed as low-intensity areas on T2WI and as signal loss on T2(?)WI. On T2WI, hyperintense abnormalities reflecting tissue edema and gliosis are also seen. Another characteristic finding is the presence of symmetrical cystic changes in the basal ganglia, which are seen in the advanced stages of this disorder. Atrophy is sometimes noted in the cerebellar and cerebral cortices. The variety in the MRI findings is specific to neuroferritinopathy. Based on observations of an excessive iron content in patients with chronic neurologic disorders, such as Parkinson disease and Alzheimer disease, the presence of excess iron is therefore recognized as a major risk factor for neurodegenerative diseases. The future development of multimodal and advanced MRI techniques is thus expected to play an important role in accurately measuring the brain iron content and thereby further elucidating the neurodegenerative process. PMID:21808735

Ohta, Emiko; Takiyama, Yoshihisa

2011-07-21

345

MRI findings in neuroferritinopathy.  

UK PubMed Central (United Kingdom)

Neuroferritinopathy is a neurodegenerative disease which demonstrates brain iron accumulation caused by the mutations in the ferritin light chain gene. On brain MRI in neuroferritinopathy, iron deposits are observed as low-intensity areas on T2WI and as signal loss on T2(?)WI. On T2WI, hyperintense abnormalities reflecting tissue edema and gliosis are also seen. Another characteristic finding is the presence of symmetrical cystic changes in the basal ganglia, which are seen in the advanced stages of this disorder. Atrophy is sometimes noted in the cerebellar and cerebral cortices. The variety in the MRI findings is specific to neuroferritinopathy. Based on observations of an excessive iron content in patients with chronic neurologic disorders, such as Parkinson disease and Alzheimer disease, the presence of excess iron is therefore recognized as a major risk factor for neurodegenerative diseases. The future development of multimodal and advanced MRI techniques is thus expected to play an important role in accurately measuring the brain iron content and thereby further elucidating the neurodegenerative process.

Ohta E; Takiyama Y

2012-01-01

346

CT findings of hypersensitivity pneumonitis  

International Nuclear Information System (INIS)

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

1989-01-01

347

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

348

Radiologic findings in neurofibromatosis  

International Nuclear Information System (INIS)

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

1979-01-01

349

MR findings in mannosidosis  

International Nuclear Information System (INIS)

MR findings are reported in three patients presenting mannosidosis. Among a family of 8 children, 4 presented typical clinical and biological abnormalities related to mannosidosis. Brain MR examinations including sagittal T1 and axial T2 sections were obtained in three patients of this family (one 25-year-old male, one 34-year-old female, and one 35-year-old female). MR scans demonstrate seven types of modifications: brachycephaly, thick calvaria, verticalization of the chiasmatic sulcus, poor pneumatization of the sphenoid body, partial empty sella turcica, cerebellar atrophy, and white matter signal modifications. High signal abnormalities involving the parieto-occipital white matter are identified on axial T2-weighted scans in the three patients and are probably related to demyelination and associated gliosis as described previously by several authors on specimens. (orig.).

1990-01-01

350

Subdural empyema: CT findings  

International Nuclear Information System (INIS)

[en] 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

351

Ultrasonographic findings of retinoblastoma  

Energy Technology Data Exchange (ETDEWEB)

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

Chung, Sung Hoo; Kang, Ik Won; Park, Yang Hee; Kim, Chu Wan; Chi, Je Geun [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1982-12-15

352

Ultrasonographic findings of retinoblastoma  

International Nuclear Information System (INIS)

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

1982-01-01

353

Hub-Based Community Finding  

CERN Multimedia

This article presents a hub-based approach to community finding in complex networks. After identifying the network nodes with highest degree (the so-called hubs), the network is flooded with wavefronts of labels emanating from the hubs, accounting for the identification of the involved communities. The simplicity and potential of this method, which is presented for direct/undirected and weighted/unweighted networks, is illustrated with respect to the Zachary karate club data, image segmentation, and concept association. Attention is also given to the identification of the boundaries between communities.

Costa, L F

2004-01-01

354

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

355

Arthroscopic findings of Kienbock's disease.  

UK PubMed Central (United Kingdom)

PURPOSE: Kienböck's disease affects the lunate bone, and osteoarthritic changes progress as the disease advances; however, relatively few studies have reported the arthroscopic findings of Kienböck's disease, and these reports have been in small populations. The purpose of this study was to review arthroscopic findings in a larger population than studied in previous reports. METHODS: We retrospectively reviewed 57 patients who underwent radial osteotomy for Kienböck's disease after arthroscopy of both the radiocarpal and midcarpal joints. All arthroscopic findings were classified as follows in terms of the location of osteoarthritic changes: lunate fossa of the radius, proximal/distal surface of the lunate bone, and capitate head. Radiological stages were classified according to the modified Lichtman's classification system. RESULTS: All but two patients had cartilage lesions in the proximal lunate cartilage. Older patients had significantly more cartilage lesions, but radiological stage showed no correlation with the number of cartilage lesions. CONCLUSIONS: This study demonstrated that the proximal lunate bone was affected in most cases of Kienböck's disease and that older patients had more cartilage lesions.

Tatebe M; Hirata H; Shinohara T; Yamamoto M; Okui N; Kurimoto S; Imaeda T

2011-11-01

356

PROBLEMS FINDING METATHINKING  

Directory of Open Access Journals (Sweden)

Full Text Available The article reflects the results of the study, the main aim of which was the designation of the basic problems of diagnosis of metathinking. In accordance with the purpose of the article presents the main diagnostic methods for metathinking, high-lighted the advantages and disadvantages of the presented methods. Based on the identified strengths and weaknesses of the main problems identified diagnostic metathinking. The article shows the results of the pilot experiment aimed to study the development of metathinking in high school. The key issues associated with the high level of uncertainty in the diagnosis of critical parameters metathinking are presented. It is concluded that the isolated problem diagnosis of metathinking, somehow, linked to each other and the solution of one problem without solving the other, is not possible. In conclusion it is also stated that the analysis of problems of diagnosis metathinking is connected with the general problem of research metathinking and metacognitive processes in general.

Samoylichenko Alexander Konstantinovich

2012-01-01

357

Calcaneal tendon: imaging findings  

International Nuclear Information System (INIS)

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

2003-01-01

358

CT findings of invasive pulmonary aspergillosis  

International Nuclear Information System (INIS)

[en] 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

1999-01-01

359

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.)

2009-01-01

360

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

 
 
 
 
361

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.

1991-01-01

362

Ultrasonographic findings of acute appendicitis  

Energy Technology Data Exchange (ETDEWEB)

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

Moon, Min Joo; Lee, Hae Ryeon; Oh, Eun Oak [Koryo General Hospital, Seoul (Korea, Republic of)

1989-04-15

363

Ultrasonographic findings of acute appendicitis  

International Nuclear Information System (INIS)

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

1989-01-01

364

Bayesian models for finding and grouping junctions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, we propose two Bayesian methods for detecting and grouping junctions. Our junction detection method evolves from the Kona approach, and it is based on a competitive greedy procedure inspired in the region competition method. Then, junction grouping is accomplished by finding connectin...

Cazorla Quevedo, Miguel Ángel; Escolano Ruiz, Francisco; Gallardo López, Domingo; Rizo Aldeguer, Ramón

365

Ultrasonographic finding of intrahepatic stones  

Energy Technology Data Exchange (ETDEWEB)

Correct diagnosis of intrahepatic stone with differentiation from extrahepatic stone is very important because of their different surgical procedure. The ultrasonography is very simple and noninvasive diagnostic method for detection of intrahepatic stone than other method. So the authors analysed the ultrasonographic findings of 30 patients with intrahepatic stones and the results are as follows: 1. Among 30 cases, 13(43.3%) were male, 17(56.7%) were female with predominancy in 5th and 6th decades. 2. 1) In distribution of stones 16 cases(53.5%) were in the left duct, 11 cases(36.7%) in both ducts, 3 cases(10%) in the right duct. 2) In location of intrahepatic stones, 9 cases(30%) were only in the intrahepatic ducts, 21 cases (70%) associated stones in the extrahepatic duct and or GB. 3. In sonography of 30 cases of intrahepatic stones 1) The shape of stone was round in 27 cases(90%) and tubular due to impacted stone in 3 cases (10%) 2) The echogenicity of stones was strong in 25 cases(83.3%) and weak in 5 cases(16.7%). 3) The shadow posterior to stones was strong in 23 cases(76.7%) and weak in 7 cases(23.3%) 4. As associated findings, metastatic lesion in liver 2 cases(6.7%), liver cirrhosis 2 cases(6.7%), hepatic and perihepatic abscess 4 cases(13.3%)were found liver(13.3%) were found

Lee, Wang Yul; Koh, Byung Hee; Cho, On Koo; Hahm, Chang Kok [Hanyang University College of Medicine, Seoul (Korea, Republic of)

1983-12-15

366

Electrophoretic finding of bisalbuminemia.  

UK PubMed Central (United Kingdom)

BACKGROUND: Bisalbuminemia or alloalbuminemia is a rare inherited or acquired condition characterized by the presence of two albumin fractions during electrophoretical separation of serum proteins. METHODS: Bisalbuminemia was incidentally detected by agarose gel electrophoresis (AGE) during standard laboratory investigation of a 36-year old female patient, referred to our laboratory with the diagnosis of immune thrombocytopenia. RESULTS: The electrophoregram showed dysproteinemia with the presence of two distinct albumin bands. This initiated testing of other family members - mother, father, and son of the patient. CONCLUSIONS: We report a case of inherited bisalbuminemia in a Bulgarian family with two affected members of four investigated. This is the first report of inherited bisalbuminemia in the Plovdiv region and could be of great interest to laboratory practitioners and clinicians providing some new data on the protein evolution and the clinical approach.

Markova V; Nenova I; Deneva T; Beleva E; Grudeva-Popova J

2013-01-01

367

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)

2009-01-01

368

Finding Ernst Mayr's Plato.  

UK PubMed Central (United Kingdom)

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."

Powers J

2013-10-01

369

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

370

MRI findings of vermian medulloblastoma  

Energy Technology Data Exchange (ETDEWEB)

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.

Jung, Seung Eun; Choi, Kyu Ho; Chung, Myung Hee; Yang, Il Kwon; Shinn, Kyung Sub; Park, Young Sub [Catholic Univ. College of Medicine, Seoul (Korea, Republic of)

1996-01-01

371

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

372

Hematological findings in Noonan syndrome  

Directory of Open Access Journals (Sweden)

Full Text Available OBJECTIVE: Noonan syndrome is a multiple congenital anomaly syndrome, and bleeding diathesis is considered part of the clinical findings. The purpose of this study was to determine the frequency of hemostatic abnormalities in a group of Noonan syndrome patients. METHOD: We studied 30 patients with clinical diagnosis of Noonan syndrome regarding their hemostatic status consisting of bleeding time, prothrombin time, activated partial thromboplastin time and thrombin time tests, a platelet count, and a quantitative determination of factor XI. RESULTS: An abnormal laboratory result was observed in 9 patients (30%). Although coagulation-factor deficiencies, especially factor XI deficiency, were the most common hematological findings, we also observed abnormalities of platelet count and function in our screening. CONCLUSIONS: Hemostatic abnormalities are found with some frequency in Noonan syndrome patients (30% in our sample). Therefore, we emphasize the importance of a more extensive hematological investigation in these patients, especially prior to an invasive procedure, which is required with some frequency in this disorder.

Bertola Débora R.; Carneiro Jorge David A.; D'Amico Élbio Antônio; Kim Chong A.; Albano Lilian Maria José; Sugayama Sofia M.M.; Gonzalez Claudette H.

2003-01-01

373

Radiologic findings of epiploic appendagitis  

International Nuclear Information System (INIS)

[en] Full text: Introduction: Epiploic appendagitis is a rare condition characterized by the ischemia and inflammation of the epiploic appendices of the colon. Its clinical features can mimic acute abdominal diseases such as diverticulitis and appendicitis. Objectives: The aim of this report is to present typical ultrasonography (US) and computed tomography (CT) features of this benign disease. Materials and method: A 44 year old man admitted to emergency department with a localized pain to umbilical region. His physical examination revealed rebound tenderness. He had no fever and his laboratory findings were normal. US examination showed a hyperechoic mass with a hypoechoic rim posterior to abdominal wall. Results: He was diagnosed with epiploic appendagitis and CT features confirmed the diagnosis. After a 5-day antibiotic treatment his clinical symptoms resolved. Conclusion: Epiploic appendagitis should be considered in the differential diagnosis of patients with an acute onset, localized pain. Because it is managed medically and has a self limited course, recognition of radiologic findings of this entity is important

2012-01-01

374

Dermoscopic findings in pyogenic granuloma.  

UK PubMed Central (United Kingdom)

BACKGROUND: To the best of our knowledge, no specific dermoscopic criteria have been described in the medical literature for the diagnosis of pyogenic granuloma. OBJECTIVES: To evaluate the morphological findings of pyogenic granuloma under dermoscopic observation. METHODS: Dermoscopic examination (using the DermLite Foto; 3Gen, LLC, Dana Point, CA, U.S.A.) of 13 patients with pyogenic granulomas was performed to evaluate specific dermoscopic criteria. RESULTS: The most frequently occurring dermoscopic features were found to be: reddish homogeneous area (92%), white collarette (85%), "white rail" lines that intersect the lesion (31%) and ulceration (46%). The results of our study reveal that the absence of specific dermoscopic criteria for other skin tumours and a reddish homogeneous area surrounded by a white collarette are the most frequent dermoscopic pattern in pyogenic granulomas (85%). CONCLUSIONS: Dermoscopy is a useful tool for improving the recognition of pyogenic granuloma.

Zaballos P; Llambrich A; Cuéllar F; Puig S; Malvehy J

2006-06-01

375

MR findings of tuberous sclerosis  

Energy Technology Data Exchange (ETDEWEB)

Magnetic resonance (MR) imaging of thirteen patients with tuberous sclerosis were reviewed. Seven patients underwent computed tomography (CT). The characteristic MR finding of tuberous sclerosis was those of subependymal nodules which were best seen on short repetition time (TR) spin-echo images. Hypointensities within the nodules consistent with calcification were most evident on long TR images. Contrast enhancing lesions, indicative subependymal giant cell astrocytoma, occurred in four cases. Cortical tubers (n = 11) and white matter lesions (n = 8) exhibited long T1 and T2 relaxation characteristics although reversed pattern was noted in one newborn patient. Cortical tubers and white matter lesions had more irregular shapes in early childhood patients. MR imaging is the sensitive method in detection of gyral tubers and white matter lesions and also valuable in detecting giant cell astrocytoma.

Moon, Woo Kyung; Kim, In One; Kim, Woo Sun; Yeon, Kyung Mo; Choo, Sung Wook; Hwang, Yong Seung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1992-11-15

376

MR findings of tuberous sclerosis  

International Nuclear Information System (INIS)

Magnetic resonance (MR) imaging of thirteen patients with tuberous sclerosis were reviewed. Seven patients underwent computed tomography (CT). The characteristic MR finding of tuberous sclerosis was those of subependymal nodules which were best seen on short repetition time (TR) spin-echo images. Hypointensities within the nodules consistent with calcification were most evident on long TR images. Contrast enhancing lesions, indicative subependymal giant cell astrocytoma, occurred in four cases. Cortical tubers (n = 11) and white matter lesions (n = 8) exhibited long T1 and T2 relaxation characteristics although reversed pattern was noted in one newborn patient. Cortical tubers and white matter lesions had more irregular shapes in early childhood patients. MR imaging is the sensitive method in detection of gyral tubers and white matter lesions and also valuable in detecting giant cell astrocytoma.

1992-01-01

377

[Arthroscopic findings after shoulder dislocation].  

UK PubMed Central (United Kingdom)

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 analyse 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 I; Radunovi? A; Madzarac D; Zori? M; Bokonji? D; Stojkovi? B

2009-07-01

378

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; Radunovi? Aleksandar; Madžarac Dragan; Zori? Miodrag; Bokonji? Dubravko; Stojkovi? Bratislav

2009-01-01

379

MR findings of polymyositis / dermatomyositis  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study was to evaluate the MR findings and useful sequences in Polymyositis/ Dermatomyositis, and to correlate MR findings with disease activity. Materials and Methods: The study included nine clinically proven cases of Polymyositis/Dermatomyositis, eight involving the thigh and one, the shoulder (2 cases, 1 follow-up). The contrast between affected and normal muscles and difference in signal intensity ratio in the muscle groups were retrospectively evaluated on Gd-enhanced T1WI and T2WI. We also evaluated the magnitude of involvement of muscle groups, fatty replacement of muscle and change of subcutaneous fat layer, and correlated signal intensity ratio with serum level of muscle enzymes. Differences in signal intensity ratio and the frequency of chemical shift artifact were evaluated on T2WI as active and inactive groups classified according to clinical findings, and the chemical shift artifact was correlated with the finding of Gd-enhanced T1WI. Except in the case of one shoulder, statistical analysis was assessed by the Anova test and-test. Results: On Gd-enhanced T1WI and T2WI contrast was 0.54 and 0.82, respectively and p value was 0.02. With regard to difference in signal intensity ratios of muscle groups, as seen on Gd-enhanced T1WI and T2WI, p valves were 0.07 and < 0.01, respectively. Muscle involvement was thus clearly visualized on T2WI. The order of frequency of involved muscle groups was vastus muscles, gluteus maximus, sartorius muscles, adductor muscles, gracilis muscle, and hamstring muscles. Fatty replacement and subcutaneous fatty change were visualized in five cases and one, respectively. The correlation coefficient between the signal intensity seen on T2WI and muscle enzymes was 0.59 (CPK) and 0.52 (LDH). The chemical-shift artifact was detected in both clinical groups (four active two inactive) and corresponded to one case of muscle involvement and five of perimuscular edema, as seen on Gd-enhanced T1WI. Conclusion: T2WI is useful for the evaluation of muscle involvement and correlated closely with disease activity; signal intensity ratio could not be substituted for the serum level of muscle enzymes. The group of thigh muscles most affected was the vastus muscles, while the hamstring muscles were least affected. The chemical-shift artifact corresponded mainly to perimuscular edema and did not correlate with disease activity.

Lee, Hak Soo; Joo, Kyung Bin; Moon, Won Jin; Lee, Tae Hee; Park, Ki Ho; Park, Dong Woo; Hahm, Chang Kok [Hanyang Univ. College of Medicine, Seoul (Korea, Republic of)

1998-07-01

380

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

 
 
 
 
381

AMTA's Find a Massage Therapist  

Science.gov (United States)

find a massage therapist Find (keyword or name) Location (city, state, or zip - Near me ) Browse techniques Questions to ask a therapist Choosing a type of massage Learn about credentials Go to full site american ...

382

CT finding of tuberculous meningitis  

International Nuclear Information System (INIS)

[en] Computerized tomographic findings of three cases with tuberculous meningitis in childhood were reported and compared with pathological findings in 2 autopsy cases of tuberculous meningitis. (J.P.N.)

1982-01-01

383

Going Local to Find Help  

Science.gov (United States)

... Past Issues Cover Story: Traumatic Brain Injury Going Local to Find Help Past Issues / Fall 2008 Table ... I need any special treatment or therapy? Finding local health and social services for survivors of TBI ...

384

Reporting of critical findings in neuroradiology.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The objective of our study was to assess compliance among academic neuroradiologists in reporting institutionally derived critical findings. MATERIALS AND METHODS: We analyzed 3054 neuroradiology CT and MRI reports generated in 1 month. Reports were categorized by whether or not they contained a critical finding based on a previously established list. The reports were subcategorized by whether the reporting neuroradiologist flagged the report as containing a critical finding and whether the radiologist verbally communicated the critical finding to the referring clinician. Reports were divided into day or night categories and the frequency of critical findings for each time period was calculated. RESULTS: Of the 3054 reports included in this study, 301 (9.9%) had critical findings. Of those 301 reports, 233 (77.4%) were flagged and the referring clinician was called. Of the remaining 68 reports with critical findings, the reporting radiologist did not call the clinician about 35.3% of them (24/68). Of the 2753 reports without critical findings, 2658 (96.5%) were appropriately not flagged and the clinician was not called. However, radiologists called clinicians about 3.5% (95/2753) of the reports without critical findings and erroneously flagged 68.4% (65/95) of those reports as critical. A majority of the cases with critical findings were reported at night (55.1%) despite the fact that 67.2% of the studies occurred during the day. CONCLUSION: Compliance with reporting and communicating critical findings must be monitored. Calling clinicians to report noncritical findings may result in unnecessary interruptions in work flow for radiologists and referring health care providers.

Viertel VG; Trotter SA; Babiarz LS; Alluwaimi F; Nagy PG; Lewin JS; Yousem DM

2013-05-01

385

EEG Findings in Behçet’s Syndrome  

Directory of Open Access Journals (Sweden)

Full Text Available Objective: To evaluate the electroencephalographic features and their relation with clinical signs in Behcet Syndrome (BS). Material and Methods: In this study, electroencephalographic records (EEG) of 40 patients (26 male and 14 female) diagnosed by BS with headache, vertigo, convulsion, cognitive impairment and psychiatrical symptoms are analyzed. Results: Sixteen (40 %) patients had normal EEG findings and 24 (60 %) of them had abnormal findings (n:11 slow activities, n:10 theta and/or sharp theta activities, n:3 diffuse alpha pattern). These findings were observed bilaterally in 18 patients, but in 4 of them, they were localized to right parietooccipital, temporocentral and posterior temporal areas, and in 2 of them they were localized to left temporocentral areas.Conclusion: The changes were nonspesific without lateralization in EEG and these findings were not correlated with neurological symptoms and/or findings in BS.

Ay?e Filiz Koç,; Deniz YERDELEN; Hacer BOZDEM?R; Eren ERKEN

2005-01-01

386

Chronic eosinophilic pneumonia: CT findings  

International Nuclear Information System (INIS)

Objective: To assess the usefulness of computerized tomography (CT) in the diagnosis of chronic eosinophilic pneumonia. Material and Methods: A double helical CT was performed in 6 patients referred to our center because of a chest X-ray with pulmonary infiltrates. Clinical presentation was cough, fever and eosinophilia in peripheral blood. Patients' age ranged from 25 to 55 years; 4 were women and 2 were men, one of the latter had a history of bronchial asthma. All patients received treatment with corticosteroids, with remission of the clinical and radiological parameters. Three patients underwent a control CT. Results: Findings consisted in focal parenchymal alterations, with areas of pulmonary consolidation and areas of 'ground glass' appearance; both patterns coexisted in certain areas. In 3 cases the lesions extended from the apices to the pulmonary bases, with predominance of the upper and middle fields. In 1 patient, there was frank predominance in the left hemi thorax. In another patient, who had a history of asthma, there were signs of pulmonary hyperinflation, with diffuse thickening of the bronchial walls, added to the previously mentioned findings, which involved the entire lung. In the mediastinum, 1 patient had lymph nodes larger than 1 cm, 3 had lymph nodes that were not enlarged but were more numerous than usual, and in the remaining patients no lymph nodes were found. The control CT's showed almost total resolution of the pulmonary infiltrates. Conclusion: The combination of eosinophilia and characteristic pulmonary infiltrates with a likely clinical presentation, associated with an optimal response to treatment with corticosteroids allows to make a reliable diagnosis and avoids the need for a pulmonary biopsy. (author)

2002-01-01

387

CT findings of Wilson's disease  

International Nuclear Information System (INIS)

[en] 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

388

Effective retention strategies for midcareer critical care nurses: a Q-method study.  

UK PubMed Central (United Kingdom)

BACKGROUND: Midcareer nurses continue to be overlooked in the current nursing shortage that is amplified in intensive care units (ICUs) requiring greater numbers of specialized nurses. OBJECTIVES: The aim of this study was to discover what midcareer critical care nurses perceive would be effective retention strategies. METHODS: As a combination of both qualitative and quantitative approaches, Q methodology was used to allow for the development of innovative strategies as well as to provide an understanding of a population of viewpoints and preferences that can guide retention efforts. Forty ICU nurses between the ages of 25 and 44 years from within a Canadian academic health science corporation completed a 45-item Q sort representing their ideas for increasing staff retention. Data were analyzed using centroid factor extraction and varimax rotation in PQMethod version 2.11. RESULTS: Four viewpoints emerged: The Healthy Workplace and Respect Seeker, The Flexibility and Reward Seeker, The Professional Development and Teamwork Seeker, and The Lifestyle Seeker. Correlations between the factors were appropriately weak, with seemingly distinct demographics characterizing each. DISCUSSION: These findings suggest a possible association between perceptions and both years of nursing experience as well as age. Implications from the study include the need to involve frontline nurses in developing strategies that will retain them. Following further investigation of the nurses' preferred strategies, it may be necessary for organizations to develop an array of retention strategies rather than implementing a single solution. In future research, generational preferences and the possible dissonance between nurse managers and frontline nurses' perceptions should be explored.

Lobo VM; Fisher A; Baumann A; Akhtar-Danesh N

2012-07-01

389

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).

2002-01-01

390

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

391

Tuberculous spondylodiscitis: MR imaging findings  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: To evaluate the MR imaging findings of tuberculous spondylodiscitis. Materials and Methods: We retrospectively evaluated the MR images of 15 patients who were diagnosed as tuberculous spondylodiscitis with percutaneous or intraoperative biopsy. Tl and T2-weighted axial and sagittal and post-contrast axial and sagittal Tl-weighted spin-echo sequences were reviewed. Results: Involvement of the vertebrae and discs were seen in all patients. The most common involvement site was thoracolumbar region. Typically, affected vertebrae and discs were hyperintense on T2-weighted images, hypointense on Tl-weighted images and showed contrast enhancement. There were paravertebral soft tissue masses in 14, vertebral body compression in 12, epidural extension in ten, kyphosis in seven, involvement of the posterior vertebral elements in two and skip lesions in three patients. Conclusion: The characteristic MR imaging features of tuberculous spondylodiscitis include Tl and T2 prolongation of the affected vertebrae and discs with contrast enhancement, vertebral bony destruction with associated paravertebral soft tissue mass, often abscess formation, epidural extension, and kyphosis. MR imaging is a reliable modality in demonstrating and characterizing the spinal tuberculosis.

Y?k?lmaz, A.; Co?kun, A.; Koç, K.; Durak, A., C.; Karahan, Ö., ?.

2004-01-01

392

Aspectos radiográficos e ultra-sonográficos dos pacientes submetidos a alongamento ósseo pelo método de Ilizarov/ Radiographic and sonographic findings in patients submitted to limb lengthening using the Ilizarov method  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Neste trabalho foram monitorados, por meio de radiografias simples e ultra-sonografias, dez pacientes submetidos a alongamento ósseo com o uso do fixador externo de Ilizarov, no período de março de 2001 a março de 2002. Os pacientes submetidos ao método de Ilizarov foram principalmente crianças e adolescentes, para correção de anomalias congênitas (seis casos). A correção do encurtamento se deveu a trauma complicado com osteomielite em três pacientes e a resse (more) cção tumoral em um paciente. O fêmur esteve envolvido em 60% dos casos, a tíbia em 30% e a fíbula em 10%. Os achados radiográficos encontrados na evolução normal do regenerado ósseo foram um centro radiotransparente, ossificação linear, reação periosteal, aumento das partes moles e ossificação completa. Os achados da formação do osso novo na ultra-sonografia foram o regenerado anecóico, ecos esparsos no sítio de distração, ecos lineares alinhados longitudinalmente, ecos grosseiros e amorfos e calcificação completa. Ocorreram 15 complicações em seis pacientes: cisto no regenerado (cinco casos), infecção adjacente aos pinos (quatro casos), coleção em partes moles (três casos), consolidação precoce (dois casos) e retardo na consolidação (um caso). Abstract in english Ten patients treated with Ilizarov external fixator for limb lengthening were monitored with radiographs and sonography examinations between March, 2001 and March, 2002. Most of the patients were children and adolescents who were submitted to surgery for correction of congenital deformities (six cases). In three patients shortening was secondary to post-traumatic osteomielitis and in one patient due to tumor resection. The femur was affected in 60%, tibia in 30% and fibul (more) a in 10% of the cases. The main radiographic findings of bone regeneration during the normal process of limb lengthening were lucent areas, linear ossification, periosteal reaction, soft tissue abnormalities and complete consolidation. Sonographic findings of new bone formation included anechoic areas, sparse echogenic foci within the distraction site, linear longitudinally oriented echogenic foci, amorphous and coarse echogenic foci and complete calcification. There were 15 complications in six patients: fluid collection at the distraction site (five cases), pin site infection (four cases), soft tissue collection (three cases), premature consolidation (two cases) and delayed consolidation (one case).

Souza, Patrícia Martins e; Marchiori, Edson; Dinoá, Vanessa A.; Knackfuss, Irocy G.

2003-12-01

393

Aspectos radiográficos e ultra-sonográficos dos pacientes submetidos a alongamento ósseo pelo método de Ilizarov Radiographic and sonographic findings in patients submitted to limb lengthening using the Ilizarov method  

Directory of Open Access Journals (Sweden)

Full Text Available Neste trabalho foram monitorados, por meio de radiografias simples e ultra-sonografias, dez pacientes submetidos a alongamento ósseo com o uso do fixador externo de Ilizarov, no período de março de 2001 a março de 2002. Os pacientes submetidos ao método de Ilizarov foram principalmente crianças e adolescentes, para correção de anomalias congênitas (seis casos). A correção do encurtamento se deveu a trauma complicado com osteomielite em três pacientes e a ressecção tumoral em um paciente. O fêmur esteve envolvido em 60% dos casos, a tíbia em 30% e a fíbula em 10%. Os achados radiográficos encontrados na evolução normal do regenerado ósseo foram um centro radiotransparente, ossificação linear, reação periosteal, aumento das partes moles e ossificação completa. Os achados da formação do osso novo na ultra-sonografia foram o regenerado anecóico, ecos esparsos no sítio de distração, ecos lineares alinhados longitudinalmente, ecos grosseiros e amorfos e calcificação completa. Ocorreram 15 complicações em seis pacientes: cisto no regenerado (cinco casos), infecção adjacente aos pinos (quatro casos), coleção em partes moles (três casos), consolidação precoce (dois casos) e retardo na consolidação (um caso).Ten patients treated with Ilizarov external fixator for limb lengthening were monitored with radiographs and sonography examinations between March, 2001 and March, 2002. Most of the patients were children and adolescents who were submitted to surgery for correction of congenital deformities (six cases). In three patients shortening was secondary to post-traumatic osteomielitis and in one patient due to tumor resection. The femur was affected in 60%, tibia in 30% and fibula in 10% of the cases. The main radiographic findings of bone regeneration during the normal process of limb lengthening were lucent areas, linear ossification, periosteal reaction, soft tissue abnormalities and complete consolidation. Sonographic findings of new bone formation included anechoic areas, sparse echogenic foci within the distraction site, linear longitudinally oriented echogenic foci, amorphous and coarse echogenic foci and complete calcification. There were 15 complications in six patients: fluid collection at the distraction site (five cases), pin site infection (four cases), soft tissue collection (three cases), premature consolidation (two cases) and delayed consolidation (one case).

Patrícia Martins e Souza; Edson Marchiori; Vanessa A. Dinoá; Irocy G. Knackfuss

2003-01-01

394

APPARATUS AND METHODS FOR PERCUTANEOUS COCHLEAR IMPLANTATION  

UK PubMed Central (United Kingdom)

A method and apparatus of percutaneous cochlear implantation (PCI). In one embodiment, the method includes the steps of (a) implanting a plurality of anchor members in a skull of a patient surrounding an ear of the patient, (b) attaching a docking frame to the plurality of anchor members, wherein the docking frame has a docking platform and a plurality of fiducial members, (c) acquiring a computed-tomography (CT) image of an area of the patient's head including the ear and the plurality of fiducial members, (d) determining a centroid of each of the plurality of fiducial members and a trajectory for a PCI according to the CT image, (e) configuring a parallel robot by a computer processor according to the CT image such that a top platform of the parallel robot is aligned with the trajectory with respect to the centroids of the plurality of fiducial members, (f) attaching the configured parallel robot to the docking frame, and (g) performing the PCI using one or more surgical tools received by the top platform of the parallel robot.

LABADIE ROBERT F; FITZPATRICK J M; MITCHELL JASON E; BLACHON GREGOIRE S; TOENNIES JENNA; WEBSTER III ROBERT J; WITHROW THOMAS J

395

Diagnostic methods in finding out the causes of infertility, results of HSG examination and laparoscopy in infertile women examined at the Gynecological Ward of the City Hospital; Metody diagnostyczne w dochodzeniu do przyczyn nieplodnosci, wyniki badan HSG i laparoskopii u nieplodnych pacjentek badanych w Oddziale Ginekologicznym Szpitala Miejskiego  

Energy Technology Data Exchange (ETDEWEB)

The paper presents diagnostic methods and the results of hysterosalpingography (HSG) and laparoscopy examination, with special attention being drawn to the usefulness of these methods in finding out the causes of infertility. 51 patients with primary and second infertility were examined. HSG and laparoscopy make it possible to diagnose correctly the cause of infertility. They also enable adequate and early classification of patients for further diagnosis and treatment at highly specialized centers dealing with the problems of infertility. (author) 8 refs, 3 tabs

Kwasniewski, S.; Kukulski, P.; Szymanski, J.; Kwasniewska, A. [Szpital Miejski, Pruszkow (Poland)

1993-12-31

396

Radiological findings in lipoid proteinosis  

Energy Technology Data Exchange (ETDEWEB)

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.

Walter, E.; Petersen, D.

1981-08-01

397

Physicians' misunderstanding of normal findings.  

UK PubMed Central (United Kingdom)

Gorry, Pauker, and Schwartz [1] demonstrated that a normal test result, when assessed quantitatively, can sometimes be extremely valuable in differential diagnosis. In the present study we extend the principle of the normal finding to include signs and symptoms. This extension proved to be clinically valuable for the present population of patients with acute cough, because the identified normal findings provided significant (p less than 0.001) information predictive of radiographic pneumonia and unrelated to that provided by the abnormal findings. This suggests that both types of findings should be used to diagnose pneumonia efficiently. Another result of the extension of this principle to signs and symptoms was the identification of the clinicians' use (p less than 0.001) of abnormal findings but not (p greater than 0.75) normal findings when managing patients with acute cough. Several possible causes for this misuse of normal findings are discussed, including limitations in the clinicians' cognitive processing of "absent problems," emphasis on abnormal findings by patients, and confusing epidemiological terminology that discourages the recognition of pertinent normal findings.

Christensen-Szalanski JJ; Bushyhead JB

1983-01-01

398

CT findings of infant epilepsy  

Energy Technology Data Exchange (ETDEWEB)

CT diagnosis of infantile epilepsy was evaluated. High incidence of abnormal CT findings in infantile spasms and Lennox-Gastaut syndrome was same as in other reports. Comparison between CT findings and neurological complications and that between CT findings and electroencephalogram findings revealed a stronger relationship existing in the former. This suggested that CT is more useful as a measure to detect underlying diseases which are due to organic change of the brain to cause epilepsy, rather than as that to disclose epileptic primary lesions of functional change.

Hojoh, Hiroatsu; Kataoka, Kenkichi; Nakagawa, Yoshihiro (Children' s Medical Center, Shizuoka (Japan)); Nakano, Shozo; Tomita, Yutaka

1982-10-01

399

Ultrasonographic findings in perforated appendicitis  

Energy Technology Data Exchange (ETDEWEB)

A retrospective analysis of surgically confirmed 45cases of perforated appendicitis was performed to evaluate sonographic findings. Inflamed appendix was visualized sonographic findings. Inflamed appendix was visualized sonographically in 42 of 45 cases. Common associated findings were loculated perpendicular fluid collection(76%), loss of appendiceal wall(76%), irregular thickening of appendiceal wall(74%)and hypertrophy of pericecal fat(57%), Other uncommon findings were free peritoneal fluid(24%), appendicoloth(19%), intramural gas(10%), and luminal dilatation of appendix(7%), Thirty-four of 45 cases could be diagnosed sonographically before surgery. The results show that ultrasonography is a useful technique in the diagnosis of perforated appendicitis and the evaluation of complication

Kim, Ye Kyung; Lim, H. K.; Bae, S. H.; Oh, Y. J.; Lee, K. W.; Jhu, I. O. [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1990-12-15