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Sample records for analyse zum snr

  1. SNR estimation for the baseband assembly

    NASA Technical Reports Server (NTRS)

    Simon, M. K.; Mileant, A.

    1986-01-01

    The expected value and the variance of the Baseband Assembly symbol signal-to-noise ratio (SNR) estimation algorithm are derived. The SNR algorithm treated here is designated as the Split Symbol Moments Estimator (SSME). It consists of averaging the first two moments of the integrated half symbols. The SSME is a biased, consistent estimator. The SNR degradation factor due to the jitter in the subcarrier demodulation and symbol synchronization loops is taken into account. Curves of the expected value of the SNR estimator versus the actual SNR are presented.

  2. Analysis and improvement of SNR using time slicing

    NASA Astrophysics Data System (ADS)

    Karanam, Srikrishna; Singh, Amarjot; Kumar, Devinder; Choubey, Akash; Bacchuwar, Ketan

    2011-06-01

    Noise is a very important factor which in most cases, plays an antagonistic role in the vast field of image processing. Thus noise needs to be studied in great depth in order to improve the quality of images. The quantity of signal in an image, corrupted by noise is generally described by the term Signal-to-Noise ratio. Capturing multiple photos at different focus settings is a powerful approach for improving SNR. The paper analyses a frame work for optimally balancing the tradeoff's between defocus and sensor noise by experimenting on synthetic as well as real video sequences. The method is first applied to synthetic image where the improvement in SNR is studied by the ability of Hough transform to extract the number of lines with respect to the variation in SNR. The paper further experiments on real time video sequences while the improvement in SNR is analyzed using different edge operators like Sobel, Canny, Prewitt, Roberts and Laplacian. The result obtained is further analyzed using different edge operators. The main aim is to detect the edges at different values of SNR which will be a prominent measure of the signal strength as well as clarity of an image. The paper also explains in depth the modeling of noise leading to better understanding of SNR. The results obtain from both synthetic image and real time video sequences elaborate the increase in SNR with the increment in the total number of time slices in a fixed budget leading to clear pictures. This technique can be very effectively applied to capture high quality images from long distances.

  3. The influence of SNR on MTF measurement

    NASA Astrophysics Data System (ADS)

    Zhang, Muxin; Liu, Liying; Li, Ye; Huan, Kewei; Zheng, Feng; Shi, Xiaoguang

    2015-11-01

    The Modulation Transfer Function (MTF) is a fundamental imaging system design specification and system quality metric often used in remote sensing. The MTF describes the attenuation of sinusoidal waveforms as a function of spatial frequency. Practically, MTF is a metric quantifying the sharpness of the reconstructed image. The Knife-Edge method is becoming widely applied for its advantage of simplified target and accurate computer calculation. Noise in CCD image system is inevitable, thus the SNR becomes a factor influencing the MTF measurement. In this paper, we build relationships between SNR, luminance and MTF. In conclusion, SNR is related with luminance levels linearly. SNR rises with increasing luminance. The higher SNR, the more curves conform to the theoretical MTF.

  4. SNR characterization in distributed acoustic sensing

    NASA Astrophysics Data System (ADS)

    Gabai, Haniel; Eyal, Avishay

    2016-05-01

    In this paper we study the SNR associated with acoustic detection in Rayleigh-based Distributed Acoustic Sensing (DAS) systems. The study is focused on phase sensitive DAS due to its superiority in terms of linearity and sensitivity. Since DAS is based on coherent interference of backscattered light from multiple scatterers it is prone to signal fading. When left unresolved, the issue of signal fading renders the associated SNR randomly dependent on position and time. Hence, its proper measurement and characterization requires statistical tools. Here such tools are introduced and a methodology for finding the mean SNR and its distribution is implemented in both experiment and simulation. It is shown that the distribution of the DAS-SNR can be obtained from the distribution of backscattered power in OTDR and the mean DAS-SNR is proportional to the energy of the interrogation pulse.

  5. Comparison of IRST systems by SNR

    NASA Astrophysics Data System (ADS)

    Kim, Charles C.; Meyer, Ron

    2014-05-01

    Infrared (IR) cameras are widely used in systems to search and track. IR search and track (IRST) systems are most often available in one of two distinct spectral bands: mid-wave IR (MWIR) or long-wave IR (LWIR). Many have compared both systems in a number of ways. The comparison included field data and analysis under different scenarios. Yet, it is a challenge to make a right decision in choosing one band over the other band for a new scenario. In some respects, the attempt is like choosing between an apple and an orange. The signal-to-noise ratio (SNR) of a system for a point-like target is one criterion that helps one to make an informed decision. The formula for SNR commonly uses noise equivalent irradiance (NEI) that requires front optics. Such formalism cannot compare two bands before a camera is built complete with front optics. We derive a formula for SNR that utilizes noise equivalent differential temperature (NEDT) that does not require front optics. The formula is further simplified under some assumptions, which identifies critical parameters and provides an insight in comparing two bands. We have shown an example for a simple case.

  6. A CHANDRA OBSERVATION OF SNR 0540 - 697

    SciTech Connect

    Seward, F. D.; Williams, R. M.; Chu, Y.-H.; Gruendl, R. A.; Dickel, J. R.

    2010-07-15

    This paper describes a Chandra observation of SNR 0540 - 697 within the H II complex N159 in the Large Magellanic Cloud (LMC). Scattering from the nearby bright source LMC X-1, which obscures the western edge of the remnant, has been removed. Larger than previously believed, the 2.'0 x 2.'8 remnant is defined by optical filaments and two lobes of X-ray emission. A band of intervening material absorbs X-rays from the central part of the remnant. The N Lobe of the remnant is relatively bright and well defined, while emission from the S Lobe is much weaker. There is structure within the N Lobe but no clear X-ray emission from an outer shell indicating a shock in the interstellar medium. The X-ray spectrum is thermal with emission lines from Fe, Mg, and Si. The observed temperature and luminosity of the hot gas are 0.6 keV and 6 x 10{sup 35} erg s{sup -1}, respectively. These are consistent with characteristics expected for older remnants. There is also diffuse thermal X-ray emission north of N159 extending into N160, evidence for a larger remnant or bubble.

  7. CO observation of SNR IC 443

    NASA Astrophysics Data System (ADS)

    Zhang, Zhiyu; Gao, Yu; Wang, Junzhi

    2010-07-01

    We present our 12CO and 13CO mapping observations of SNR IC 443 interacting with molecular clouds. It is the first large-scale high-resolution 13CO mapping observation in the surrounding region. The morphologies of IC 443 in 12CO and 13CO are compared with the optical, infrared, Spitzer far-infrared, X-ray, and neutral atomic gas (HI). We also make comparison and analysis in the kinematics, using the date-cubes of 12CO, 13CO and HI, to help distinguish the complicated gas motions in the shocked regions. Based on the work of Wang & Scoville (1992), we present a new model to explain the coexistence of multiple shocks with different speeds in a pc-scale region at the central clump B. We test this new model by analyzing the HI and CO distribution in both velocity and space domain. We also establish the relationship between the dissociation rate of shocked molecular gas and the shock velocity in this region. Finally, we derive the optical depth of 12CO with the 13CO spectra in clump B, and discuss the validity of the assumption of optically thin emission for the shocked 12CO.

  8. Impact of CCD camera SNR on polarimetric accuracy.

    PubMed

    Chen, Zhenyue; Wang, Xia; Pacheco, Shaun; Liang, Rongguang

    2014-11-10

    A comprehensive charge-coupled device (CCD) camera noise model is employed to study the impact of CCD camera signal-to-noise ratio (SNR) on polarimetric accuracy. The study shows that the standard deviations of the measured degree of linear polarization (DoLP) and angle of linear polarization (AoLP) are mainly dependent on the camera SNR. With increase in the camera SNR, both the measurement errors and the standard deviations caused by the CCD camera noise decrease. When the DoLP of the incident light is smaller than 0.1, the camera SNR should be at least 75 to achieve a measurement error of less than 0.01. When the input DoLP is larger than 0.5, a SNR of 15 is sufficient to achieve the same measurement accuracy. An experiment is carried out to verify the simulation results.

  9. Fe K and ejecta emission in SNR G15.9+0.2 with XMM-Newton

    NASA Astrophysics Data System (ADS)

    Maggi, Pierre; Acero, Fabio

    2016-06-01

    We present a study of the Galactic supernova remnant SNR G15.9+0.2 with archival XMM-Newton observations. Using EPIC's collective power, we report for the first time the detection of Fe K line emission from SNR G15.9+0.2. We measure the line properties (e.g. centroid energy and width) and find evidence for spatial variations. We discuss how SNR G15.9+0.2 fits within the current sample of SNRs with detected Fe K emission and found that it is the core-collapse SNR with the lowest Fe K centroid energy. We also present some caveats to the use of Fe K line centroid energies as typing tools for SNRs. We analyse the emission-line rich X-ray spectra extracted from various regions. The abundances of Mg, Si, S, Ar, and Ca are super-solar and their ratios strongly suggests that the progenitor of SNR G15.9+0.2 was a massive star, strengthening the physical association to a candidate Central Compact Object detected with Chandra. Using the absorption column density and ambient medium density constrained by the X-ray spectral analysis, we revise the measurements of the age and distance to the SNR.

  10. SNR of swept SLEDs and swept lasers for OCT.

    PubMed

    Johnson, Bart; Atia, Walid; Flanders, Dale C; Kuznetsov, Mark; Goldberg, Brian D; Kemp, Nate; Whitney, Peter

    2016-05-16

    A back-to-back comparison of a tunable narrow-band-filtered SLED (TSLED) and a swept laser are made for OCT applications. The two sources are similar in terms of sweep speed, tuning range and coherence length. A fundamental issue with a TSLED is that the RIN is proportional to 1/linewidth, meaning that the longer the coherence length, the higher the RIN and clock jitter. We show that the TSLED has an SNR limit that causes noise streaks at points of high reflection in images. The laser, which is shot noise limited, does not exhibit this effect. We add noise terms proportional to the sample power times reference power to standard swept source SNR expressions to account for the SNR limit. PMID:27409939

  11. Customer oriented SNR scalability scheme for scalable video coding

    NASA Astrophysics Data System (ADS)

    Li, Z. G.; Rahardja, S.

    2005-07-01

    Let the whole region be the whole bit rate range that customers are interested in, and a sub-region be a specific bit rate range. The weighting factor of each sub-region is determined according to customers' interest. A new type of region of interest (ROI) is defined for the SNR scalability as the gap between the coding efficiency of SNR scalability scheme and that of the state-of-the-art single layer coding for a sub-region is a monotonically non-increasing function of its weighting factor. This type of ROI is used as a performance index to design a customer oriented SNR scalability scheme. Our scheme can be used to achieve an optimal customer oriented scalable tradeoff (COST). The profit can thus be maximized.

  12. Tracking low SNR targets using particle filter with flow control

    NASA Astrophysics Data System (ADS)

    Moshtagh, Nima; Romberg, Paul M.; Chan, Moses W.

    2014-06-01

    In this work we study the problem of detecting and tracking challenging targets that exhibit low signal-to-noise ratios (SNR). We have developed a particle filter-based track-before-detect (TBD) algorithm for tracking such dim targets. The approach incorporates the most recent state estimates to control the particle flow accounting for target dynamics. The flow control enables accumulation of signal information over time to compensate for target motion. The performance of this approach is evaluated using a sensitivity analysis based on varying target speed and SNR values. This analysis was conducted using high-fidelity sensor and target modeling in realistic scenarios. Our results show that the proposed TBD algorithm is capable of tracking targets in cluttered images with SNR values much less than one.

  13. SNR and noise measurements for medical imaging: I. A practical approach based on statistical decision theory.

    PubMed

    Tapiovaara, M J; Wagner, R F

    1993-01-01

    A method of measuring the image quality of medical imaging equipment is considered within the framework of statistical decision theory. In this approach, images are regarded as random vectors and image quality is defined in the context of the image information available for performing a specified detection or discrimination task. The approach provides a means of measuring image quality, as related to the detection of an image detail of interest, without reference to the actual physical mechanisms involved in image formation and without separate measurements of signal transfer characteristics or image noise. The measurement does not, however, consider deterministic errors in the image; they need a separate evaluation for imaging modalities where they are of concern. The detectability of an image detail can be expressed in terms of the ideal observer's signal-to-noise ratio (SNR) at the decision level. Often a good approximation to this SNR can be obtained by employing sub-optimal observers, whose performance correlates well with the performance of human observers as well. In this paper the measurement of SNR is based on implementing algorithmic realizations of specified observers and analysing their responses while actually performing a specified detection task of interest. Three observers are considered: the ideal prewhitening matched filter, the non-prewhitening matched filter, and the DC-suppressing non-prewhitening matched filter. The construction of the ideal observer requires an impractical amount of data and computing, except for the most simple imaging situations. Therefore, the utilization of sub-optimal observers is advised and their performance in detecting a specified signal is discussed. Measurement of noise and SNR has been extended to include temporally varying images and dynamic imaging systems. PMID:8426870

  14. Whole Symbol Moments SNR Estimator (WSME) Analysis and Implementation

    NASA Astrophysics Data System (ADS)

    Kuperman, I.; Satorius, E.

    2012-08-01

    Adaptive data rate (ADR) functionality was added to the Mars Reconnaissance Orbiter (MRO) Electra software-defined radio (SDR) via software and firmware uploads to its modem in October 2011. An integral part of ADR is the symbol signal-to-noise ratio (SNR) estimation algorithm. The Whole Symbol Moments SNR Estimator (WSME) algorithm has been developed for ADR control and was included in the October 2011 upload. It is the subject of this article. The WSME architecture is described and performance results are presented via analysis, simulation, and data from an inflight MRO test on March 5, 2012.

  15. Rigorous Estimation of SNR of a PSK Communication Link

    NASA Technical Reports Server (NTRS)

    Manning, Robert M.

    2006-01-01

    An improved method of estimating the signal-to-noise ratio (SNR) of a phase-shift keying (PSK) communication link is founded on a rigorous statistical analysis of the input to, and the output from, the PSK demodulator in the receiver. The improved method is free of unwarranted simplifying assumptions and does not require the use of a propagation receiver.

  16. Improved Diffusion Imaging through SNR-Enhancing Joint Reconstruction

    PubMed Central

    Haldar, Justin P.; Wedeen, Van J.; Nezamzadeh, Marzieh; Dai, Guangping; Weiner, Michael W.; Schuff, Norbert; Liang, Zhi-Pei

    2012-01-01

    Quantitative diffusion imaging is a powerful technique for the characterization of complex tissue microarchitecture. However, long acquisition times and limited signal-to-noise ratio (SNR) represent significant hurdles for many in vivo applications. This paper presents a new approach to reduce noise while largely maintaining resolution in diffusion weighted images, using a statistical reconstruction method that takes advantage of the high level of structural correlation observed in typical datasets. Compared to existing denoising methods, the proposed method performs reconstruction directly from the measured complex k-space data, allowing for Gaussian noise modeling and theoretical characterizations of the resolution and SNR of the reconstructed images. In addition, the proposed method is compatible with many different models of the diffusion signal (e.g., diffusion tensor modeling, q-space modeling, etc.). The joint reconstruction method can provide significant improvements in SNR relative to conventional reconstruction techniques, with a relatively minor corresponding loss in image resolution. Results are shown in the context of diffusion spectrum imaging tractography and diffusion tensor imaging, illustrating the potential of this SNR-enhancing joint reconstruction approach for a range of different diffusion imaging experiments. PMID:22392528

  17. SNR improvement for hyperspectral application using frame and pixel binning

    NASA Astrophysics Data System (ADS)

    Rehman, Sami Ur; Kumar, Ankush; Banerjee, Arup

    2016-05-01

    Hyperspectral imaging spectrometer systems are increasingly being used in the field of remote sensing for variety of civilian and military applications. The ability of such instruments in discriminating finer spectral features along with improved spatial and radiometric performance have made such instruments a powerful tool in the field of remote sensing. Design and development of spaceborne hyper spectral imaging spectrometers poses lot of technological challenges in terms of optics, dispersion element, detectors, electronics and mechanical systems. The main factors that define the type of detectors are the spectral region, SNR, dynamic range, pixel size, number of pixels, frame rate, operating temperature etc. Detectors with higher quantum efficiency and higher well depth are the preferred choice for such applications. CCD based Si detectors serves the requirement of high well depth for VNIR band spectrometers but suffers from smear. Smear can be controlled by using CMOS detectors. Si CMOS detectors with large format arrays are available. These detectors generally have smaller pitch and low well depth. Binning technique can be used with available CMOS detectors to meet the large swath, higher resolution and high SNR requirements. Availability of larger dwell time of satellite can be used to bin multiple frames to increase the signal collection even with lesser well depth detectors and ultimately increase the SNR. Lab measurements reveal that SNR improvement by frame binning is more in comparison to pixel binning. Effect of pixel binning as compared to the frame binning will be discussed and degradation of SNR as compared to theoretical value for pixel binning will be analyzed.

  18. Chandra ACIS Survey of M33: The SNR Population

    NASA Astrophysics Data System (ADS)

    Plucinsky, Paul; Long, Knox S.; Gaetz, Terrance; Tuellmann, Ralph

    The Chandra ACIS Survey of M33 (ChASeM33) is a large program to survey the inner re-gions of the M33 galaxy. The survey consists of 7 different fields observed for 200 ks (each field observed twice for 100 ks), covering 70the key projects of the ChASeM33 project is to characterize the SNR population in M33. We have detected 82 of 137 optically-identified SNRs and SNR candidates with a limiting X-ray luminosity of 2.0e34 ergs/s (0.35-2.0 keV), yielding confirmation of (or at least strongly supporting) their SNR identifications. This represents the largest sample of remnants detected at optical and X-ray wavelengths in any galaxy, including the Milky Way. With the high angular resolution of Chandra, we are able to study the X-ray morphology of the bright remnants for the first time. A spectral analysis of the seven X-ray brightest SNRs reveals that two, G98-31 and G98-35, have spectra that appear to indicate enrichment by ejecta from core-collapse supernova explosions. A comparison of the X-ray lu-minosity function of the SNRs in M33 to the LMC and SMC indicates that the LMC, and to a lesser extent the SMC, have more, high luminosity SNRs than M33. We did not discover any close analogs of Cas A, Kepler's SNR, Tycho's SNR or the Crab Nebula in the regions of M33 surveyed, but we have found an X-ray source with a power law spectrum coincident with a small-diameter radio source that may be the first pulsar-wind nebula recognized in M33.

  19. HYPR: constrained reconstruction for enhanced SNR in dynamic medical imaging

    NASA Astrophysics Data System (ADS)

    Mistretta, C.; Wieben, O.; Velikina, J.; Wu, Y.; Johnson, K.; Korosec, F.; Unal, O.; Chen, G.; Fain, S.; Christian, B.; Nalcioglu, O.; Kruger, R. A.; Block, W.; Samsonov, A.; Speidel, M.; Van Lysel, M.; Rowley, H.; Supanich, M.; Turski, P.; Wu, Yan; Holmes, J.; Kecskemeti, S.; Moran, C.; O'Halloran, R.; Keith, L.; Alexander, A.; Brodsky, E.; Lee, J. E.; Hall, T.; Zagzebski, J.

    2008-03-01

    During the last eight years our group has developed radial acquisitions with angular undersampling factors of several hundred that accelerate MRI in selected applications. As with all previous acceleration techniques, SNR typically falls as least as fast as the inverse square root of the undersampling factor. This limits the SNR available to support the small voxels that these methods can image over short time intervals in applications like time-resolved contrast-enhanced MR angiography (CE-MRA). Instead of processing each time interval independently, we have developed constrained reconstruction methods that exploit the significant correlation between temporal sampling points. A broad class of methods, termed HighlY Constrained Back PRojection (HYPR), generalizes this concept to other modalities and sampling dimensions.

  20. Radiometric calibration and SNR calculation of a SWIR imaging telescope

    SciTech Connect

    Yilmaz, Ozgur; Turk, Fethi; Selimoglu, Ozgur

    2012-09-06

    Radiometric calibration of an imaging telescope is usually made using a uniform illumination sphere in a laboratory. In this study, we used the open-sky images taken during bright day conditions to calibrate our telescope. We found a dark signal offset value and a linear response coefficient value for each pixel by using three different algorithms. Then we applied these coefficients to the taken images, and considerably lowered the image non-uniformity. Calibration can be repeated during the operation of telescope with an object that has better uniformity than open-sky. Also SNR (Signal to Noise Ratio) of each pixel was calculated from the open-sky images using the temporal mean and standard deviations. It is found that SNR is greater than 80 for all pixels even at low light levels.

  1. Stochastic acceleration and magnetic damping in Tycho's SNR

    NASA Astrophysics Data System (ADS)

    Wilhelm, Alina; Telezhinsky, Igor; Dwarkadas, Vikram; Pohl, Martin

    2016-06-01

    Tycho's Supernova remnant (SNR) is also known as historical Supernova SN 1572 of Type Ia. Having exploded in a relatively clean environment and with a known age, it represents an ideal astrophysical testbed for the study of cosmic-ray acceleration and related phenomena. A number of studies suggest that shock acceleration with very efficient magnetic-field amplification is needed to explain the rather soft radio spectrum and the narrow rims observed in X-rays. We show that the wideband spectrum of Tycho's SNR can be alternatively well explained when accounting for stochastic acceleration as a secondary process. The re-acceleration of particles in the turbulent region immediately downstream of the shock provided by the fast-mode waves is efficient enough to impact particle spectra over several decades in energy. Our self-consistent model contains hydrodynamic simulations of the SNR plasma flow. The particle spectra are obtained from the time-dependent transport equation and the background magnetic field is computed either from the induction equation or it follows analytic profiles depending on the considered model. Although not as efficient as standard diffusive shock acceleration, stochastic acceleration leaves its imprint on the particle spectra. This is especially notable in the emission at radio wavelengths and soft γ-rays. Excessively strong magnetic fields and the so-called Alfvénic drift are not required in this scenario. The narrow X-ray and radio rims arise from damping of the turbulent magnetic field. We find a lower limit for the downstream magnetic field strength, Bd = 173 µG and investigate the energy-dependence of the X-ray filament width. We conclude that stochastic re-acceleration is an important mechanism for modifying particle and emission spectra in SNR and that the magnetic-field damping should be taken into account to properly explain the synchrotron intensity profiles of Tycho.

  2. A new method of pulse edge detection in low SNR

    NASA Astrophysics Data System (ADS)

    Fan, Xiaolei; Li, Tao; Su, Shaoying; Chen, Zengping

    2015-12-01

    In this paper, we propose a new pulse edge detection method based on short time Fourier transform (STFT) and difference of boxes (DOB) filter. Firstly, detect the coarse starting and ending positions in frequency domain after STFT. Then obtain the precise pulse edge through DOB filter. It achieves a better performance than the classical energy detection (ED) method, especially when signal to noise ratio (SNR) is low. Simulation results and real data application validate the effectiveness of the proposed method.

  3. SNR-adaptive stream weighting for audio-MES ASR.

    PubMed

    Lee, Ki-Seung

    2008-08-01

    Myoelectric signals (MESs) from the speaker's mouth region have been successfully shown to improve the noise robustness of automatic speech recognizers (ASRs), thus promising to extend their usability in implementing noise-robust ASR. In the recognition system presented herein, extracted audio and facial MES features were integrated by a decision fusion method, where the likelihood score of the audio-MES observation vector was given by a linear combination of class-conditional observation log-likelihoods of two classifiers, using appropriate weights. We developed a weighting process adaptive to SNRs. The main objective of the paper involves determining the optimal SNR classification boundaries and constructing a set of optimum stream weights for each SNR class. These two parameters were determined by a method based on a maximum mutual information criterion. Acoustic and facial MES data were collected from five subjects, using a 60-word vocabulary. Four types of acoustic noise including babble, car, aircraft, and white noise were acoustically added to clean speech signals with SNR ranging from -14 to 31 dB. The classification accuracy of the audio ASR was as low as 25.5%. Whereas, the classification accuracy of the MES ASR was 85.2%. The classification accuracy could be further improved by employing the proposed audio-MES weighting method, which was as high as 89.4% in the case of babble noise. A similar result was also found for the other types of noise.

  4. The multipath and SNR Quality in civil code L2

    NASA Astrophysics Data System (ADS)

    Polezel, W. G.; Souza, E. M.; Monico, J. F.

    2007-12-01

    The new generation of GPS satellites, with the addition of the new L2C civil code, may provide to the users better positioning capabilities. The new code in the L2 may increase the signal robustness, improve resistance to interference, reduce tracking noise and consequently, improve accuracy and provide better positioning inside buildings and in wooded areas. The second civil frequency code will eliminate the need of using fragile semi- codeless tracking techniques currently used in connection with L2. The L2C has a different structure that allows civil and military share the same code. L2C owns two codes of different length: moderate code (CM) and long code (CL). The CM was chosen to have 10.230 chips repeated to every 20 millisecond. The CL was chosen to have 767250 chips with period of 1.5 second. The main reasons for these choices were due to excellent correlation properties. Furthermore, L2C enhances performance by having no data modulation on CL code, which improves, among others, the threshold tracking performance. Comparing the L2C acquisition with the C/A, the CM code is ten times longer than the C/A and the two components have half the total power. This is an important feature for many low-power applications. Although this signal has several advantages, some investigations about its performance are necessary, mainly about the provided accuracy under some effects, for example, multipath. Thus, this paper aims to analyze the L2C signal, as well as its quality using some parameters, such as Signal to Noise Ratio (SNR) and multipath level (MP). The experiment was realized at Sao Paulo State University UNESP in Presidente Prudente, Brazil. The data were collected by two receivers of different brands, both able to collect the L2C signal, and connected to the same antenna, thought the use of a splitter. The results showed that the MP and SNR values were better for the modernized satellites. Furthermore, the SNR values of the two receivers were similar while the

  5. Physik gestern und heute Von der Metallstange zum Hochenergielaser

    NASA Astrophysics Data System (ADS)

    Heering, Peter

    2002-05-01

    Im Mai 1752 wurde in Marly bei Paris auf Anregung des amerikanischen Forschers und Politikers Benjamin Franklin erstmals die elektrische Natur des Blitzes nachgewiesen. Damals beschrieb Franklin auch eine technische Vorrichtung, die als Schutz von Gebäuden vor Blitzschlägen dienen sollte: den Blitzableiter. Diese aus heutiger Sicht scheinbar triviale Vorrichtung wurde aber keineswegs unmittelbar akzeptiert. Und bis heute ist die Forschung zum Schutz von Einrichtungen vor Blitzschlägen nicht abgeschlossen.

  6. Shocked Molecular Gas in the SNR 3C391

    NASA Astrophysics Data System (ADS)

    Bock, D. C.-J.; Wright, M. C. H.; Frail, D. A.; Gaensler, B. M.; Wilner, D. J.

    1999-05-01

    The discovery of OH (1720 MHz) masers in supernova remnants (SNRs) provides us with a convenient method for identifying promising candidates for studies of SNR/molecular cloud interactions. One remnant which is an ideal subject is 3C391. Here, single dish observations reveal a myriad of molecular lines from a giant shocked cloud at the blast-wave of the remnant. We present recent millimeter-wave observations of 3C391 with the Berkeley-Illinois-Maryland Association (BIMA) array. We have imaged the region towards the OH maser in HCN (J=1--0) and HCO+ (J=1--0) at a resolution of 4 arcsec. The morphology and brightness of the emission in HCO+ and HCN are similar; we resolve the shocked cloud seen by Frail and Mitchell (1998) into several clumps of characteristic size 10 arcsec. The maser is midway between two of these clumps, rather than being coincident with the peak column density. The clumps all have similar spectra with line-widths of ~ 30 km s(-1) , although there is evidence for a velocity gradient between the clumps. We examine the physical conditions of the shocked environment and discuss the relative abundances of the molecules. A companion study of the interaction between the SNR W51C and an associated molecular cloud is underway.

  7. Carrier tracking by smoothing filter improves symbol SNR

    NASA Technical Reports Server (NTRS)

    Pomalaza-Raez, Carlos A.; Hurd, William J.

    1986-01-01

    The potential benefit of using a smoothing filter to estimate carrier phase over use of phase locked loops (PLL) is determined. Numerical results are presented for the performance of three possible configurations of the deep space network advanced receiver. These are residual carrier PLL, sideband aided residual carrier PLL, and finally sideband aiding with a Kalman smoother. The average symbol signal to noise ratio (SNR) after losses due to carrier phase estimation error is computed for different total power SNRs, symbol rates and symbol SNRs. It is found that smoothing is most beneficial for low symbol SNRs and low symbol rates. Smoothing gains up to 0.4 dB over a sideband aided residual carrier PLL, and the combined benefit of smoothing and sideband aiding relative to a residual carrier loop is often in excess of 1 dB.

  8. Suzaku observations of SNR1987A - a rusty remnent?

    NASA Astrophysics Data System (ADS)

    Hasinger, G.; Itoh, M.; Bamba, A.; Terada, Y.; Mori, K.; Kenzaki, K.; Suzaku Snr1987A Observation Team

    We report results of Suzaku observations of SNR1987A focused on the XIS data The observations were made on November 4 2005 day 6829 after the explosion The spectrum is described with two-component thermal emission models The temperatures of the two components are sim 0 3 keV and sim 2 7 keV respectively The X-ray flux in 0 5-2 keV band was 2 28 pm 0 06 times 10 -12 erg cm -2 s -1 which follows the exponential rise with the time scale of sim 800 days since day sim 4000 after the explosion Assuming that the two components have the same elemental abundances deficiency of O and Fe was observed while the abundances of N Si and S showed higher values than the average of the LMC One of the possible interpretations of the deficiency of O and Fe is that these elements are confined in dust grains

  9. SNR and Contrast Enhancement Techniques for the Photoacoustic Radar Imaging

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Mandelis, Andreas

    2016-07-01

    This paper presents two methods for photoacoustic signal enhancement in biological tissues. One such method is based on the fact that temperature can affect the signals of the photoacoustic radar. Therefore, thermally assisted methods have been used for photoacoustic imaging contrast improvement. Another method is based on harmonic wavelength modulation which results in a differential PA radar signal to strengthen early cancer detection. Two chirped waveforms modulated out-of-phase between 680 nm and 800 nm can effectively suppress the background noise, greatly enhance the SNR and detect small variations in hemoglobin oxygenation levels, thereby distinguishing pre-malignant tumors. Experimental results demonstrate the accuracy of the frequency-modulated differential measurement with sheep blood at different hemoglobin oxygenation (S_tO2) levels.

  10. Recent developments on the SNR-CR connection

    NASA Astrophysics Data System (ADS)

    Amato, Elena

    2016-06-01

    The last few years have been rich of progress both for the science of Supernova Remnants and for Cosmic Rays. We have learnt from X-ray observations of SNRs that they host multi-TeV electrons and amplified magnetic fields, likely hints of efficient CR acceleration. We have seen gamma-ray emission from SNRs and gathered direct evidence of the presence of relativistic hadrons at least in a couple of these sources. Finally we have learnt how to properly use optical emission lines as a diagnostic of efficient CR acceleration in SNRs. On the CR side, direct experiments have shown the first clear evidence of structure in the spectra of protons and He nuclei below the knee, and in the meantime very recent measurements cast doubt about the position of the protons' knee. After briefly reviewing these recent developments, I will discuss whether and how they fit within the current theoretical framework of the SNR-CR connection.

  11. Using the GPS SNR Technique to Detect Volcanic Plumes

    NASA Astrophysics Data System (ADS)

    Naik, S. R.; Mattia, M.; Larson, K. M.; Rossi, M.; Bruno, V.; Coltelli, M.; Ohta, Y.; Schneider, D. J.

    2015-12-01

    Detection of volcanic plumes, especially ash-laden ones, is important both for public health and aircraft safety. A variety of geophysical tools and satellite data are used to monitor volcanic eruptions and to predict the movement of ash. However, satellite-based methods are restricted by time of day and weather, while radars are often unavailable because of cost/ portability. GPS instruments are frequently deployed near volcanos, but typically they have only been used to measure deformation. Here a method is proposed to detect volcanic plumes using GPS signal to noise ratio (SNR) data. The strengths and limitations of the method are assessed using GPS data collected during eruptions at Mt. Redoubt (2009) and Mt. Etna (2013). Plume detections are compared with independently collected seismic and radar data.

  12. An SNR improvement of passive SAW tags with 5-bit Barker code sequence

    NASA Astrophysics Data System (ADS)

    Bae, Hyunchul; Kim, Jaekwon; Burm, Jinwook

    2012-07-01

    Passive surface acoustic wave (SAW) tags require a large signal-to-noise ratio (SNR) in order to increase the interrogation range. For the purpose of achieving high SNR for radio frequency identification (RFID) communication systems, Barker codes, a binary phase shift keying (BPSK) modulation technique, have been adopted in this study. Passive SAW RFID tags were designed with 5-bit Barker code sequences to generate BPSK modulated signals. Through the SNR analysis, the improvements in SNR were about 11 dB using Barker codes along with a correlator, which can be further improved by optimisation in the correlator.

  13. SNR 1987A: the birth of a Supernova Remnant

    NASA Astrophysics Data System (ADS)

    Bouchet, Patrice; Danziger, John

    Observations show that the infrared emission from dust observed in Supernovae and Supernova Remants originates both from the freshly synthesized dust in the expanding envelope and from pre-existing dust in the CSM. There are some few cases where it is suggested that dust formed recently in the CSM as a result of interaction with the expanding emvelope. The mass of dust in these various environments is, with a few exceptions, poorly determined. However the few estimates of the dust mass condensed in the ejecta make questionable so far any claims for supernovae being significant dust factories. This is the case in particular for SNR 1987A. We present up to date multiwavelength observations of this incipient remnant obtained with the VLT, Gemini, Chandra, Hubble and Spitzer Space Telescope. The various light curves show that the morphology and luminosity of the remnant are rapidly changing at X-ray, optical, and infrared wavelengths as the blast wave from the explosion expands into the circumstellar equatorial ring produced by mass loss from the progenitor 20000 years before the explosion. The observed IR/soft-X-ray flux ratio (IRX) is consistent with that of a dusty plasma with standard LMC dust abundances. This ratio decreased between days 6190 and 7137, providing the first direct observation of dust destruction, and has been remarkably stable since that date (up to day 8000), which might indicate that the episode of destruction has terminated. We show that the main components of the dust grains present in the ring are silicates and a model consistent with the observations has been elaborated. There remain some spectral features which are not explained. In addition, the lack of a strong correlation between images obtained in the visible (hot spots) and in the mid-infrared (dust clumps) also makes the precise location of the soft X-ray emitting region uncertain. The composition of the grains that have condensed in the ejecta of SN 1987A is still not known with

  14. Multi-frequency observations of SNR J0453-6829 in the LMC. A composite supernova remnant with a pulsar wind nebula

    NASA Astrophysics Data System (ADS)

    Haberl, F.; Filipović, M. D.; Bozzetto, L. M.; Crawford, E. J.; Points, S. D.; Pietsch, W.; De Horta, A. Y.; Tothill, N.; Payne, J. L.; Sasaki, M.

    2012-07-01

    Context. The Large Magellanic Cloud (LMC) is rich in supernova remnants (SNRs), which can be investigated in detail with radio, optical, and X-ray observations. SNR J0453-6829 is an X-ray and radio-bright remnant in the LMC, within which previous studies revealed the presence of a pulsar wind nebula (PWN), making it one of the most interesting SNRs in the Local Group of galaxies. Aims: We study the emission of SNR J0453-6829 to improve our understanding of its morphology, spectrum, and thus the emission mechanisms in the shell and the PWN of the remnant. Methods: We obtained new radio data with the Australia Telescope Compact Array and analysed archival XMM-Newton observations of SNR J0453-6829. We studied the morphology of SNR J0453-6829 from radio, optical, and X-ray images and investigated the energy spectra in the different parts of the remnant. Results: Our radio results confirm that this LMC SNR hosts a typical PWN. The prominent central core of the PWN exhibits a radio spectral index αCore of -0.04 ± 0.04, while in the rest of the SNR shell the spectral slope is somewhat steeper with αShell = -0.43 ± 0.01. We detect regions with a mean polarisation of P ≅ (12 ± 4)% at 6 cm and (9 ± 2)% at 3 cm. The full remnant is of roughly circular shape with dimensions of (31 ± 1) pc × (29 ± 1) pc. The spectral analysis of the XMM-Newton EPIC and RGS spectra allowed us to derive physical parameters for the SNR. Somewhat depending on the spectral model, we obtain for the remnant a shock temperature of around 0.2 keV and estimate the dynamical age to 12 000-15 000 years. Using a Sedov model we further derive an electron density in the X-ray emitting material of 1.56 cm-3, typical for LMC remnants, a large swept-up mass of 830 M⊙, and an explosion energy of 7.6 × 1050 erg. These parameters indicate a well evolved SNR with an X-ray spectrum dominated by emission from the swept-up material.

  15. SNR bounds of FSO links and its evaluation for selected beams

    NASA Astrophysics Data System (ADS)

    Eyyuboğlu, Halil T.; Bayraktar, Mert

    2015-09-01

    We formulate the signal-to-noise ratio (SNR) for free-space optical links. Upon inserting typical operating parameters, it is seen that SNR well approximates to the inverse of aperture averaged scintillation parameter. By adopting a common source beam power of 10 mW, we select three different source sizes of Gaussian, annular Gaussian (AG), and cosh-Gaussian beams. We then evaluate the SNR of these beams. Our results indicate that when fixed aperture opening is used, fully and partially coherent beams yield almost the same SNR performance. On the other hand, however, focusing and lowering wavelength of operation appear to be quite instrumental in improving the SNR performance. In this context, medium-sized AGB seems to exhibit the best performance.

  16. An octahedral shear strain-based measure of SNR for 3D MR elastography

    NASA Astrophysics Data System (ADS)

    McGarry, M. D. J.; Van Houten, E. E. W.; Perriñez, P. R.; Pattison, A. J.; Weaver, J. B.; Paulsen, K. D.

    2011-07-01

    A signal-to-noise ratio (SNR) measure based on the octahedral shear strain (the maximum shear strain in any plane for a 3D state of strain) is presented for magnetic resonance elastography (MRE), where motion-based SNR measures are commonly used. The shear strain, γ, is directly related to the shear modulus, μ, through the definition of shear stress, τ = μγ. Therefore, noise in the strain is the important factor in determining the quality of motion data, rather than the noise in the motion. Motion and strain SNR measures were found to be correlated for MRE of gelatin phantoms and the human breast. Analysis of the stiffness distributions of phantoms reconstructed from the measured motion data revealed a threshold for both strain and motion SNR where MRE stiffness estimates match independent mechanical testing. MRE of the feline brain showed significantly less correlation between the two SNR measures. The strain SNR measure had a threshold above which the reconstructed stiffness values were consistent between cases, whereas the motion SNR measure did not provide a useful threshold, primarily due to rigid body motion effects.

  17. Optimal filters - A unified approach for SNR and PCE. [Peak-To-Correlation-Energy

    NASA Technical Reports Server (NTRS)

    Juday, Richard D.

    1993-01-01

    A unified approach for a general metric that encompasses both the signal-to-noise ratio (SNR) and the peak-to-correlation (PCE) ratio in optical correlators is described. In this approach, the connection between optimizing SNR and optimizing PCE is achieved by considering a metric in which the central correlation irradiance is divided by the total energy of the correlation plane. The peak-to-total energy (PTE) is shown to be optimized similarly to SNR and PCE. Since PTE is a function of the search values G and beta, the optimal filter is determined with only a two-dimensional search.

  18. [Analysis of the effect of detector's operating temperature on SNR in space-based remote sensor].

    PubMed

    Li, Zhan-feng; Wang, Shu-rong; Huang, Yu

    2012-03-01

    Limb viewing is a new viewing geometry for space-based atmospheric remote sensing, but the spectral radiance of atmosphere scattering reduces rapidly with limb height. So the signal-noise-ratio (SNR) is a key performance parameter of limb remote sensor. A SNR model varying with detector's temperature is proposed, based on analysis of spectral radiative transfer and noise' source in representative instruments. The SNR at limb height 70 km under space conditions was validated by simulation experiment on limb remote sensing spectrometer prototype. Theoretic analysis and experiment's results indicate congruously that when detector's temperature reduces to some extent, a maximum SNR will be reached. After considering the power consumption, thermal conductivity and other issues, optimal operating temperature of detector can be decided.

  19. Spatially Resolved Spectroscopy of the SNR IC443

    NASA Astrophysics Data System (ADS)

    Gorenstein, P.

    1998-07-01

    IC 443 is a supernova remnant of intermediate age, i.e. a few thousand years. It is especially interesting because part of its periphery is expanding into a molecular cloud while other sections are expanding into a typical interstellar medium of much lower density. Since the evolution of a supernova remnant through its various phases is affected by the density of the medium it expands into with the reasonable assumption that the supernova explosion was approximately symmetric we have an opportunity to observe a single object in two phases simultaneously. It was observed by ASCA in April, 1993 for a short period during the PV phase and more thoroughly in a 42 ksec exposure in March, 1994. The latter measurement provides most of the results that have been reported. Most of the analysis took place after the grant ended but is included here for completeness. The data was sent simultaneously to US and Japanese Pls. We worked independently. The software set of FTOOLs was used to construct images and spectra. They were judged to be rather unintuitive and not at all user friendly. I found I was using one FTOOL to read the header to obtain information that would only be provided to another FTOOL. The Japanese investigators were more successful. They analyzed the data and published results more rapidly. The scientific results summarized below are based primarily on their publications. Since IC 443 is an interesting example of a middle aged SNR in which a variety of processes are occurring it is one of a class. IC 443 exhibits shell-like emission in hard X-rays and extended soft X-rays with thin thermal spectra. It resembles SN 1006 in these respects. IC 443 contains hard X-rays in a semi-circular shell surrounding the thermal component. The total hard X-ray flux in the ASCA FOV is only a half of the Ginga hard component; which suggests that the hard X-rays are not confined only in the shell but some are extended larger than the ASCA FOV of eq 1 degree diameter. Japanese

  20. Spatially Resolved Spectroscopy of the SNR IC443

    NASA Technical Reports Server (NTRS)

    Gorenstein, P.

    1998-01-01

    IC 443 is a supernova remnant of intermediate age, i.e. a few thousand years. It is especially interesting because part of its periphery is expanding into a molecular cloud while other sections are expanding into a typical interstellar medium of much lower density. Since the evolution of a supernova remnant through its various phases is affected by the density of the medium it expands into with the reasonable assumption that the supernova explosion was approximately symmetric we have an opportunity to observe a single object in two phases simultaneously. It was observed by ASCA in April, 1993 for a short period during the PV phase and more thoroughly in a 42 ksec exposure in March, 1994. The latter measurement provides most of the results that have been reported. Most of the analysis took place after the grant ended but is included here for completeness. The data was sent simultaneously to US and Japanese Pls. We worked independently. The software set of FTOOLs was used to construct images and spectra. They were judged to be rather unintuitive and not at all user friendly. I found I was using one FTOOL to read the header to obtain information that would only be provided to another FTOOL. The Japanese investigators were more successful. They analyzed the data and published results more rapidly. The scientific results summarized below are based primarily on their publications. Since IC 443 is an interesting example of a middle aged SNR in which a variety of processes are occurring it is one of a class. IC 443 exhibits shell-like emission in hard X-rays and extended soft X-rays with thin thermal spectra. It resembles SN 1006 in these respects. IC 443 contains hard X-rays in a semi-circular shell surrounding the thermal component. The total hard X-ray flux in the ASCA FOV is only a half of the Ginga hard component; which suggests that the hard X-rays are not confined only in the shell but some are extended larger than the ASCA FOV of eq 1 degree diameter. Japanese

  1. The upper limits of the SNR in radiography and CT with polyenergetic x-rays.

    PubMed

    Shikhaliev, Polad M

    2010-09-21

    The aim of the study is to determine the upper limits of the signal-to-noise ratio (SNR) in radiography and computed tomography (CT) with polyenergetic x-ray sources. In x-ray imaging, monoenergetic x-rays provide a higher SNR compared to polyenergetic x-rays. However, the SNR in polyenergetic x-ray imaging can be increased when a photon-counting detector is used and x-rays are optimally weighted according to their energies. For a particular contrast/background combination and at a fixed x-ray entrance skin exposure, the SNR in energy-weighting x-ray imaging depends on tube voltage and can be maximized by selecting the optimal tube voltage. The SNR in energy-weighted x-ray images acquired at this optimal tube voltage is the highest SNR that can be achieved with polyenergetic x-ray sources. The optimal tube voltages and the highest SNR were calculated and compared to the SNR of monoenergetic x-ray imaging. Monoenergetic, energy-weighting polyenergetic and energy-integrating polyenergetic x-ray imagings were simulated at a fixed entrance skin exposure of 20 mR. The tube voltages varied in the range of 30-140 kVp with 10 kV steps. Contrast elements of CaCO(3), iodine, adipose and tumor with thicknesses of 280 mg cm(-2), 15 mg cm(-2), 1 g cm(-2) and 1 g cm(-2), respectively, inserted in a soft tissue background with 10 cm and 20 cm thicknesses, were used. The energy weighting also improves the contrast-to-noise ratio (CNR) in CT when monoenergetic CT projections are optimally weighted prior to CT reconstruction (projection-based weighting). Alternatively, monoenergetic CT images are reconstructed, optimally weighted and composed to yield a final CT image (image-based weighting). Both projection-based and image-based weighting methods improve the CNR in CT. An analytical approach was used to determine which of these two weighting methods provides the upper limit of the CNR in CT. The energy-weighting method was generalized and expanded as a weighting method applicable

  2. Influence of range-gated intensifiers on underwater imaging system SNR

    NASA Astrophysics Data System (ADS)

    Wang, Xia; Hu, Ling; Zhi, Qiang; Chen, Zhen-yue; Jin, Wei-qi

    2013-08-01

    Range-gated technology has been a hot research field in recent years due to its high effective back scattering eliminating. As a result, it can enhance the contrast between a target and its background and extent the working distance of the imaging system. The underwater imaging system is required to have the ability to image in low light level conditions, as well as the ability to eliminate the back scattering effect, which means that the receiver has to be high-speed external trigger function, high resolution, high sensitivity, low noise, higher gain dynamic range. When it comes to an intensifier, the noise characteristics directly restrict the observation effect and range of the imaging system. The background noise may decrease the image contrast and sharpness, even covering the signal making it impossible to recognize the target. So it is quite important to investigate the noise characteristics of intensifiers. SNR is an important parameter reflecting the noise features of a system. Through the use of underwater laser range-gated imaging prediction model, and according to the linear SNR system theory, the gated imaging noise performance of the present market adopted super second generation and generation Ⅲ intensifiers were theoretically analyzed. Based on the active laser underwater range-gated imaging model, the effect to the system by gated intensifiers and the relationship between the system SNR and MTF were studied. Through theoretical and simulation analysis to the image intensifier background noise and SNR, the different influence on system SNR by super second generation and generation Ⅲ ICCD was obtained. Range-gated system SNR formula was put forward, and compared the different effect influence on the system by using two kind of ICCDs was compared. According to the matlab simulation, a detailed analysis was carried out theoretically. All the work in this paper lays a theoretical foundation to further eliminating back scattering effect, improving

  3. Hot Gas in SMC SNR 0057-7226 and the Giant H 2 Region N66

    NASA Astrophysics Data System (ADS)

    Danforth, C. W.; Hoopes, C. G.; Sankrit, R.; Chu, Y.-H.; Sembach, K. R.; Blair, W. P.

    2001-12-01

    The supernova remnant SNR 0057-7226 and the dense, young cluster NGC 346 lie within the giant H 2 region N66, the most active star formation site in the SMC. Far Ultraviolet Spectroscopic Explorer (FUSE) observations of the Wolf-Rayet binary system HD 5980, which lies behind the SNR, show high velocity, O 6 and C 3 absorption associated with the far side of the remnant (Hoopes et al 2001, ApJ, 558, L35). Chandra ACIS-I and ROSAT HRI images of N66 show the diffuse X-ray emission associated with the SNR, but little or no diffuse emission around the core of the central cluster. We present high-dispersion, long-slit optical echelle observations of five positions within N66 including positions across the SNR 0057-7226 and NGC 346. These data show bright Hα emission at the SMC rest velocity (v ~155 km s-1). Where the spectrograph slits intersect the SNR, faint Hα emission at high (v ~300 km s-1) and low (v ~50 km s-1) velocities reveals clumps of material on the back and front sides of the SNR shell. Ten FUSE observations of sight lines toward stars in N66--including four toward NGC 346 cluster stars--provide sensitive absorption-line measurements of several ionic species including O 6 which traces hot (T ~3*E5 K), highly-ionized gas and Fe 2 which traces cooler (T ~104 K), ionized and neutral gas. We also present ground based optical narrowband images in Hα , [S 2], and [O 3] which show the morphology of the H 2 region. We use this data set to study the kinematics of the gas in this complex region and to model the properties of the SNR-ISM interaction. This work is supported by NASA Contract NAS5-32985 to the Johns Hopkins University.

  4. Zum Stellenwert der Unterdruck-Instillationstherapie in der Dermatologie.

    PubMed

    Müller, Cornelia Sigrid Lissi; Burgard, Barbara; Zimmerman, Monika; Vogt, Thomas; Pföhler, Claudia

    2016-08-01

    Die Methoden zur Behandlung akuter und chronischer Wunden unterliegen einer steten Weiterentwicklung, Reevaluierung und Anwendung innovativer Therapieformen. Die Vakuumtherapie zur Wundbehandlung gehört zu den etablierten Behandlungsmodalitäten. Ein innovatives Verfahren kombiniert die Vakuumtherapie mit der automatisierten, kontrollierten Zufuhr und Drainage wirkstoffhaltiger Lösungen zur topischen Wundbehandlung im Wundbett und auch wirkstofffrei durch Instillation physiologischer Kochsalzlösung (Unterdruck-Instillationstherapie). Hierdurch können die Effekte der konventionellen Vakuumtherapie mit denen der lokalen Antisepsis kombiniert werden. Hierdurch kommt es zu einer Reduktion der Wundfläche, einer Induktion von Granulationsgewebe sowie einer Reduktion der Keimbesiedelung der Wunden. Bisher publizierte Studien konzentrieren sich auf die Anwendung dieses Therapieverfahrens zur Behandlung orthopädisch-chirurgischer Krankheiten. Die Datenlage bezüglich der Vakuum-Instillationstherapie in der Dermatochirurgie beschränkt sich derzeit auf Fallberichte und Einzelfallerfahrungen. Randomisierte, prospektive Studien zum Vergleich der Vakuum-Instillationstherapie zur Behandlung dermatologischer Krankheitsbilder existieren bislang nicht. Ziele des vorliegenden Artikels sind die Vorstellung der Vakuumtherapie mit Instillation einschließlich ihres Wirkprinzips, deren mögliche Komplikationen, die Diskussion erdenklicher Kontraindikationen sowie eine Übersicht über die aktuell verfügbare Datenlage. Zusammenfassend scheint sich die Evidenz zu verdichten, dass mittels Unterdruck-Instillationstherapie sowohl einfache als auch komplizierte Wunden effizient behandelt werden können, was sich in einer deutlichen Beschleunigung der Wundgranulation mit konsekutiv früher möglichem Defektverschluss äußert. PMID:27509413

  5. Enhanced leavening ability of baker's yeast by overexpression of SNR84 with PGM2 deletion.

    PubMed

    Lin, Xue; Zhang, Cui-Ying; Bai, Xiao-Wen; Xiao, Dong-Guang

    2015-06-01

    Dough-leavening ability is one of the main aspects considered when selecting a baker's yeast strain for baking industry. Generally, modification of maltose metabolic pathway and known regulatory networks of maltose metabolism were used to increase maltose metabolism to improve leavening ability in lean dough. In this study, we focus on the effects of PGM2 (encoding for the phosphoglucomutase) and SNR84 (encoding for the H/ACA snoRNA) that are not directly related to both the maltose metabolic pathway and known regulatory networks of maltose metabolism on the leavening ability of baker's yeast in lean dough. The results show that the modifications on PGM2 and/or SNR84 are effective ways in improving leavening ability of baker's yeast in lean dough. Deletion of PGM2 decreased cellular glucose-1-phosphate and overexpression of SNR84 increased the maltose permease activity. These changes resulted in 11, 19 and 21% increases of the leavening ability for PGM2 deletion, SNR84 overexpression and SNR84 overexpression combining deleted PGM2, respectively.

  6. Is the gamma-ray emission from the SNR HESS J1731-347 leptonic dominated ?

    NASA Astrophysics Data System (ADS)

    Acero, Fabio; Renaud, Matthieu; Lemoine-Goumard, Marianne; Rousseau, Romain

    2012-07-01

    HESS J1731-347 is the first supernova remnant (SNR) that has been discovered based on TeV observation. First an unassociated source discovered in the survey of the Galactic plane by the HESS experiment, it has later been identified as a new SNR (through radio and X-rays observations) and is now the 4th object in the restricted club of SNRs with a TeV shell morphology. This new SNR shares many similarities with the brightest TeV SNR RX J1713.7-3946: comparable TeV luminosities, lack of thermal X-ray emission and the remnants from a gravitational core collapse (compact objects observed at the center). Using the spectral and morphological information derived in TeV, the GeV emission of the SNR is investigated with data from the Fermi Gamma-ray Space Telescope in order to test whether the nature of the gamma-ray emission is of leptonic (as it has been found for RX J1713.7-3946) or hadronic origin.

  7. Enhanced leavening ability of baker's yeast by overexpression of SNR84 with PGM2 deletion.

    PubMed

    Lin, Xue; Zhang, Cui-Ying; Bai, Xiao-Wen; Xiao, Dong-Guang

    2015-06-01

    Dough-leavening ability is one of the main aspects considered when selecting a baker's yeast strain for baking industry. Generally, modification of maltose metabolic pathway and known regulatory networks of maltose metabolism were used to increase maltose metabolism to improve leavening ability in lean dough. In this study, we focus on the effects of PGM2 (encoding for the phosphoglucomutase) and SNR84 (encoding for the H/ACA snoRNA) that are not directly related to both the maltose metabolic pathway and known regulatory networks of maltose metabolism on the leavening ability of baker's yeast in lean dough. The results show that the modifications on PGM2 and/or SNR84 are effective ways in improving leavening ability of baker's yeast in lean dough. Deletion of PGM2 decreased cellular glucose-1-phosphate and overexpression of SNR84 increased the maltose permease activity. These changes resulted in 11, 19 and 21% increases of the leavening ability for PGM2 deletion, SNR84 overexpression and SNR84 overexpression combining deleted PGM2, respectively. PMID:25877163

  8. SNR Wall Effect Alleviation by Generalized Detector Employed in Cognitive Radio Networks.

    PubMed

    Shbat, Modar Safir; Tuzlukov, Vyacheslav

    2015-01-01

    The most commonly used spectrum sensing techniques in cognitive radio (CR) networks, such as the energy detector (ED), matched filter (MF), and others, suffer from the noise uncertainty and signal-to-noise ratio (SNR) wall phenomenon. These detectors cannot achieve the required signal detection performance regardless of the sensing time. In this paper, we explore a signal processing scheme, namely, the generalized detector (GD) constructed based on the generalized approach to signal processing (GASP) in noise, in spectrum sensing of CR network based on antenna array with the purpose to alleviate the SNR wall problem and improve the signal detection robustness under the low SNR. The simulation results confirm our theoretical issues and effectiveness of GD implementation in CR networks based on antenna array. PMID:26151216

  9. Towards optimum demodulation of bandwidth-limited and low SNR square-wave subcarrier signals

    NASA Technical Reports Server (NTRS)

    Feria, Y.; Hurd, W.

    1995-01-01

    The optimum phase detector is presented for tracking square-wave subcarriers that have been bandwidth limited to a finite number of harmonics. The phase detector is optimum in the sense that the loop signal-to-noise ratio (SNR) is maximized and, hence, the rms phase tracking error is minimized. The optimum phase detector is easy to implement and achieves substantial improvement. Also presented are the optimum weights to combine the signals demodulated from each of the harmonics. The optimum weighting provides SNR improvement of 0.1 to 0.15 dB when the subcarrier loop SNR is low (15 dB) and the number of harmonics is high (8 to 16).

  10. SNR Wall Effect Alleviation by Generalized Detector Employed in Cognitive Radio Networks

    PubMed Central

    Shbat, Modar Safir; Tuzlukov, Vyacheslav

    2015-01-01

    The most commonly used spectrum sensing techniques in cognitive radio (CR) networks, such as the energy detector (ED), matched filter (MF), and others, suffer from the noise uncertainty and signal-to-noise ratio (SNR) wall phenomenon. These detectors cannot achieve the required signal detection performance regardless of the sensing time. In this paper, we explore a signal processing scheme, namely, the generalized detector (GD) constructed based on the generalized approach to signal processing (GASP) in noise, in spectrum sensing of CR network based on antenna array with the purpose to alleviate the SNR wall problem and improve the signal detection robustness under the low SNR. The simulation results confirm our theoretical issues and effectiveness of GD implementation in CR networks based on antenna array. PMID:26151216

  11. SNR Wall Effect Alleviation by Generalized Detector Employed in Cognitive Radio Networks.

    PubMed

    Shbat, Modar Safir; Tuzlukov, Vyacheslav

    2015-07-03

    The most commonly used spectrum sensing techniques in cognitive radio (CR) networks, such as the energy detector (ED), matched filter (MF), and others, suffer from the noise uncertainty and signal-to-noise ratio (SNR) wall phenomenon. These detectors cannot achieve the required signal detection performance regardless of the sensing time. In this paper, we explore a signal processing scheme, namely, the generalized detector (GD) constructed based on the generalized approach to signal processing (GASP) in noise, in spectrum sensing of CR network based on antenna array with the purpose to alleviate the SNR wall problem and improve the signal detection robustness under the low SNR. The simulation results confirm our theoretical issues and effectiveness of GD implementation in CR networks based on antenna array.

  12. Highly accurate SNR measurement using the covariance of two SEM images with the identical view.

    PubMed

    Oho, Eisaku; Suzuki, Kazuhiko

    2012-01-01

    Quality of an SEM image is strongly influenced by the extent of noise. As a well-known method in the field of SEM, the covariance is applied to measure the signal-to-noise ratio (SNR). This method has potential ability for highly accurate measurement of the SNR, which is hardly known until now. If the precautions discussed in this article are adopted, that method can demonstrate its real ability. These precautions are strongly related to "proper acquisition of two images with the identical view," "alignment of an aperture diaphragm," "reduction of charging phenomena," "elimination of particular noises," and "accurate focusing," As necessary, characteristics in SEM signal and noise are investigated from a few standpoints. When using the maximum performance of this measurement, SNR of many SEM images obtained in a variety of the SEM operating conditions and specimens can be measured accurately.

  13. High Velocity Gas in the Line of Sight to the Vela SNR

    NASA Technical Reports Server (NTRS)

    Nichols, Joy S.; Slavin, Jonathan D.

    2004-01-01

    One of the best objects for study of the structure, kinematics, and evolutionary status of a middle-aged supernova remnant (SNR) is the VELA SNR, due to its proximity, extensive optical filamentary structure, and an abundance of hot background stars for absorption line research. The VELA remnant is 7.3 degrees in diameter, based on x-ray imagery with ROSAT, with the pulsar nearly centered in the remnant. The western region of the remnant has much lower x-ray surface brightness than the remainder of the remnant and in fact escaped earlier detection with previous instrumentation. The remnant is believed to be about 11,000 years old.

  14. Thermally enhanced signal strength and SNR improvement of photoacoustic radar module

    PubMed Central

    Wang, Wei; Mandelis, Andreas

    2014-01-01

    A thermally enhanced method for improving photoacoustic imaging depth and signal-to-noise (SNR) ratio is presented in this paper. Experimental results showed that the maximum imaging depth increased by 20% through raising the temperature of absorbing biotissues (ex-vivo beef muscle) uniformly from 37 to 43°C, and the SNR was increased by 8%. The parameters making up the Gruneisen constant were investigated experimentally and theoretically. The studies showed that the Gruneisen constant of biotissues increases with temperature, and the results were found to be consistent with the photoacousitc radar theory. PMID:25136501

  15. Estimators of The Magnitude-Squared Spectrum and Methods for Incorporating SNR Uncertainty.

    PubMed

    Lu, Yang; Loizou, Philipos C

    2011-07-01

    Statistical estimators of the magnitude-squared spectrum are derived based on the assumption that the magnitude-squared spectrum of the noisy speech signal can be computed as the sum of the (clean) signal and noise magnitude-squared spectra. Maximum a posterior (MAP) and minimum mean square error (MMSE) estimators are derived based on a Gaussian statistical model. The gain function of the MAP estimator was found to be identical to the gain function used in the ideal binary mask (IdBM) that is widely used in computational auditory scene analysis (CASA). As such, it was binary and assumed the value of 1 if the local SNR exceeded 0 dB, and assumed the value of 0 otherwise. By modeling the local instantaneous SNR as an F-distributed random variable, soft masking methods were derived incorporating SNR uncertainty. The soft masking method, in particular, which weighted the noisy magnitude-squared spectrum by the a priori probability that the local SNR exceeds 0 dB was shown to be identical to the Wiener gain function. Results indicated that the proposed estimators yielded significantly better speech quality than the conventional MMSE spectral power estimators, in terms of yielding lower residual noise and lower speech distortion. PMID:21886543

  16. Approaching Ultimate Intrinsic SNR in a Uniform Spherical Sample with Finite Arrays of Loop Coils

    PubMed Central

    Vaidya, Manushka V.; Sodickson, Daniel K.; Lattanzi, Riccardo

    2015-01-01

    We investigated to what degree and at what rate the ultimate intrinsic (UI) signal-to-noise ratio (SNR) may be approached using finite radiofrequency detector arrays. We used full-wave electromagnetic field simulations based on dyadic Green’s functions to compare the SNR of arrays of loops surrounding a uniform sphere with the ultimate intrinsic SNR (UISNR), for increasing numbers of elements over a range of magnetic field strengths, voxel positions, sphere sizes, and acceleration factors. We evaluated the effect of coil conductor losses and the performance of a variety of distinct geometrical arrangements such as “helmet” and “open-pole” configurations in multiple imaging planes. Our results indicate that UISNR at the center is rapidly approached with encircling arrays and performance is substantially lower near the surface, where a quadrature detection configuration tailored to voxel position is optimal. Coil noise is negligible at high field, where sample noise dominates. Central SNR for practical array configurations such as the helmet is similar to that of close-packed arrangements. The observed trends can provide physical insights to improve coil design. PMID:26097442

  17. Capacity analysis of threshold-based SNR scheduler in LTE systems

    NASA Astrophysics Data System (ADS)

    Sulyman, Ahmed Iyanda; Ahmad, Ishtiaq; Hassanein, Hossam; Alshebeili, Saleh A.

    2013-12-01

    This paper presents the capacity analysis of a threshold-based SNR scheduler in the long-term evolution (LTE) cellular systems. LTE standard has adopted multiuser OFDMA, and stipulates adjacent subcarrier groupings for mapping the physical OFDM subcarriers into resource blocks that form the basic unit of radio resource management (RRM) in LTE network. The standard however did not specify the details of the RRM algorithm to be employed, leaving this aspect for vendors to differentiate their products. Popular RRM algorithms such as round-robin (RR), proportional fairness (PF), and maximum SNR (MaxSNR), have been implemented recently as operator-selectable options on LTE base station (BS). In this paper, we present a threshold-based SNR scheduler that has the capability of modeling all of the above-mentioned algorithms and thus allows vendors to combine the separate implementations of these algorithms into one generalized scheduling algorithm, where the threshold level used at any time instant defines the scheduling discipline to be realized. We derive the capacity enhancement achievable using the proposed scheduling scheme, and also present system-level simulations to corroborate the analysis. Our analytical and simulation results indicate that the proposed algorithm models the existing ones closely at different values of the threshold. The results also demonstrate the data rate enhancements, and the level of user fairness, achievable in the network for various levels of the threshold.

  18. GROND observations of GRB 160622A/SNR RCW 103/SGR 1617-5103

    NASA Astrophysics Data System (ADS)

    Schady, P.; Kann, D. A.; Greiner, J.

    2016-06-01

    We observed the field of GRB 160622A/SNR RCW 103/SGR 1617-5103 (Swift trigger 700791; D'Ai et al., GCN #19547. ATel #9180) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile).

  19. Estimators of The Magnitude-Squared Spectrum and Methods for Incorporating SNR Uncertainty

    PubMed Central

    Lu, Yang; Loizou, Philipos C.

    2011-01-01

    Statistical estimators of the magnitude-squared spectrum are derived based on the assumption that the magnitude-squared spectrum of the noisy speech signal can be computed as the sum of the (clean) signal and noise magnitude-squared spectra. Maximum a posterior (MAP) and minimum mean square error (MMSE) estimators are derived based on a Gaussian statistical model. The gain function of the MAP estimator was found to be identical to the gain function used in the ideal binary mask (IdBM) that is widely used in computational auditory scene analysis (CASA). As such, it was binary and assumed the value of 1 if the local SNR exceeded 0 dB, and assumed the value of 0 otherwise. By modeling the local instantaneous SNR as an F-distributed random variable, soft masking methods were derived incorporating SNR uncertainty. The soft masking method, in particular, which weighted the noisy magnitude-squared spectrum by the a priori probability that the local SNR exceeds 0 dB was shown to be identical to the Wiener gain function. Results indicated that the proposed estimators yielded significantly better speech quality than the conventional MMSE spectral power estimators, in terms of yielding lower residual noise and lower speech distortion. PMID:21886543

  20. Multi-GNSS and Multi-frequency SNR Multipath Reflectometry of Snow Depth

    NASA Astrophysics Data System (ADS)

    Tabibi, S.; Geremia-Nievinski, F.; van Dam, T. M.

    2015-12-01

    Global Navigation Satellite System multipath reflectometry (GNSS-MR) uses ground-based signals of opportunity to retrieve snow depth at an intermediate space scale. This technique is based on the signal-to-noise ratio (SNR) of the simultaneously received direct (line-of-sight) and coherently ground reflected signals. In this contribution, forward and inverse modeling of SNR observations is presented for GLONASS-MR, extending GPS-MR to multiple GNSS. The coupling of the surface and antenna responses from short-delay near-grazing incidence multipath from CDMA and FDMA satellite navigation systems are simulated using an electromagnetic forward model. The inverse model is used to estimate parameter corrections responsible for observation residuals to estimate snow depth. The correlation between snow depth retrievals using GPS L2C signal and GLONASS R2-C/A signal is excellent, with r2 value of 0.990. In a related approach, dual-frequency SNR-based GNSS-MR, which is based on linear combination of SNR observables, is used to estimate snow depth. This ionospheric delay free method synthesizes longer carrier wavelengths ("widelaning" or delta-k) to isolate the direct power contribution in environmental retrievals.

  1. A new SNR with TeV shell-type morphology: HESS J1731-347

    NASA Astrophysics Data System (ADS)

    H.E.S.S. Collaboration; Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Balzer, A.; Barnacka, A.; Barres de Almeida, U.; Becherini, Y.; Becker, J.; Behera, B.; Bernlöhr, K.; Bochow, A.; Boisson, C.; Bolmont, J.; Bordas, P.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Büsching, I.; Carrigan, S.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Chounet, L.-M.; Clapson, A. C.; Coignet, G.; Cologna, G.; Conrad, J.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; Drury, L. O'C.; Dubois, F.; Dubus, G.; Dutson, K.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Farnier, C.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gallant, Y. A.; Gast, H.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Goret, P.; Göring, D.; Häffner, S.; Hague, J. D.; Hampf, D.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hoffmann, A.; Hofmann, W.; Hofverberg, P.; Holler, M.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jamrozy, M.; Jung, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Keogh, D.; Khangulyan, D.; Khélifi, B.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Laffon, H.; Lamanna, G.; Lennarz, D.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Masbou, J.; Maurin, D.; Maxted, N.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Moderski, R.; Moulin, E.; Naumann, C. L.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nguyen, N.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; de Oña Wilhelmi, D.; Opitz, B.; Ostrowski, M.; Oya, I.; Panter, M.; Paz Arribas, M.; Pedaletti, G.; Pelletier, G.; Petrucci, P.-O.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raue, M.; Rayner, S. M.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Ruppel, J.; Ryde, F.; Sahakian, V.; Santangelo, A.; Schlickeiser, R.; Schöck, F. M.; Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Sikora, M.; Skilton, J. L.; Sol, H.; Spengler, G.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Szostek, A.; Tavernet, J.-P.; Terrier, R.; Tluczykont, M.; Valerius, K.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Vialle, J. P.; Viana, A.; Vincent, P.; Völk, H. J.; Volpe, F.; Vorobiov, S.; Vorster, M.; Wagner, S. J.; Ward, M.; White, R.; Wierzcholska, A.; Zacharias, M.; Zajczyk, A.; Zdziarski, A. A.; Zech, A.; Zechlin, H.-S.

    2011-07-01

    Aims: The recent discovery of the radio shell-type supernova remnant (SNR), G353.6-0.7, in spatial coincidence with the unidentified TeV source HESS J1731-347 has motivated further observations of the source with the High Energy Stereoscopic System (HESS) Cherenkov telescope array to test a possible association of the γ-ray emission with the SNR. Methods: With a total of 59 h of observation, representing about four times the initial exposure available in the discovery paper of HESS J1731-347, the γ-ray morphology is investigated and compared with the radio morphology. An estimate of the distance is derived by comparing the interstellar absorption derived from X-rays and the one obtained from 12CO and HI observations. Results: The deeper γ-ray observation of the source has revealed a large shell-type structure with similar position and extension (r ~ 0.25°) as the radio SNR, thus confirming their association. By accounting for the HESS angular resolution and projection effects within a simple shell model, the radial profile is compatible with a thin, spatially unresolved, rim. Together with RX J1713.7-3946, RX J0852.0-4622 and SN 1006, HESS J1731-347 is now the fourth SNR with a significant shell morphology at TeV energies. The derived lower limit on the distance of the SNR of 3.2 kpc is used together with radio and X-ray data to discuss the possible origin of the γ-ray emission, either via inverse Compton scattering of electrons or the decay of neutral pions resulting from proton-proton interaction.

  2. Type Ia SNR N103B: structure of the remnant and properties of the progenitor

    NASA Astrophysics Data System (ADS)

    Li, C.-J.; Chu, Y.-H.; Gruendl, R.; et al.

    2016-06-01

    N103B is a Type Ia supernova remnant (SNR) projected in the outskirt of the superbubble around the rich cluster NGC 1850 in the Large Magellanic Cloud (LMC). We have obtained Hubble Space Telescope (HST) images to study the physical structure of this SNR and its underlying stellar population. We have also obtained high- and medium-dispersion spectra of the SNR to identify the shocked gas components and to determine the excitation and abundances of the gas. The HST H-alpha image of N103B shows an incomplete filamentary elliptical shell and several groups of prominent knots. Our long-slit, high-dispersion spectra show that the filamentary shell is dominated by hydrogen Balmer lines; its lack of forbidden line emission indicates that the filamentary shell results from collisionless shocks into a mostly neutral medium. In contrast, the prominent knots show large velocity widths in both H-alpha line and [N II] 6548, 6583 lines. Furthermore, the [S II] 6716/6731 ratios in the knots imply electron densities >5000 /cm^-3. These spectral properties suggest that these knots are most likely circumstellar material ejected by the progenitor before the SN explosion. Interestingly, using our high-dispersion spectra, we found that the N103B SNR is inside a slow expanding shell (V_exp ~10 km/s). This kinematically identified shell is not visible morphologically. Considering the optical and X-ray properties of N103B and the discovery of the slow expanding shell encompassing the SNR, we suggest that the progenitor of N103B is a single-degenerate binary system; furthermore, the progenitor moved through the interstellar medium roughly along the minor axis of the filamentary elliptical shell. The supernova explosion center can be approximated by the center of the elliptical shell, and used to search for the surviving companion of the supernova. We suggest possible candidates for the surviving companion and implications on its mass and evolutionary stage.

  3. Fractal dimension analysis for spike detection in low SNR extracellular signals

    NASA Astrophysics Data System (ADS)

    Salmasi, Mehrdad; Büttner, Ulrich; Glasauer, Stefan

    2016-06-01

    Objective. Many algorithms have been suggested for detection and sorting of spikes in extracellular recording. Nevertheless, it is still challenging to detect spikes in low signal-to-noise ratios (SNR). We propose a spike detection algorithm that is based on the fractal properties of extracellular signals and can detect spikes in low SNR regimes. Semi-intact spikes are low-amplitude spikes whose shapes are almost preserved. The detection of these spikes can significantly enhance the performance of multi-electrode recording systems. Approach. Semi-intact spikes are simulated by adding three noise components to a spike train: thermal noise, inter-spike noise, and spike-level noise. We show that simulated signals have fractal properties which make them proper candidates for fractal analysis. Then we use fractal dimension as the main core of our spike detection algorithm and call it fractal detector. The performance of the fractal detector is compared with three frequently used spike detectors. Main results. We demonstrate that in low SNR, the fractal detector has the best performance and results in the highest detection probability. It is shown that, in contrast to the other three detectors, the performance of the fractal detector is independent of inter-spike noise power and that variations in spike shape do not alter its performance. Finally, we use the fractal detector for spike detection in experimental data and similar to simulations, it is shown that the fractal detector has the best performance in low SNR regimes. Significance. The detection of low-amplitude spikes provides more information about the neural activity in the vicinity of the recording electrodes. Our results suggest using the fractal detector as a reliable and robust method for detecting semi-intact spikes in low SNR extracellular signals.

  4. A Novel Speed Compensation Method for ISAR Imaging with Low SNR

    PubMed Central

    Liu, Yongxiang; Zhang, Shuanghui; Zhu, Dekang; Li, Xiang

    2015-01-01

    In this paper, two novel speed compensation algorithms for ISAR imaging under a low signal-to-noise ratio (SNR) condition have been proposed, which are based on the cubic phase function (CPF) and the integrated cubic phase function (ICPF), respectively. These two algorithms can estimate the speed of the target from the wideband radar echo directly, which breaks the limitation of speed measuring in a radar system. With the utilization of non-coherent accumulation, the ICPF-based speed compensation algorithm is robust to noise and can meet the requirement of speed compensation for ISAR imaging under a low SNR condition. Moreover, a fast searching implementation strategy, which consists of coarse search and precise search, has been introduced to decrease the computational burden of speed compensation based on CPF and ICPF. Experimental results based on radar data validate the effectiveness of the proposed algorithms. PMID:26225980

  5. A Novel Speed Compensation Method for ISAR Imaging with Low SNR.

    PubMed

    Liu, Yongxiang; Zhang, Shuanghui; Zhu, Dekang; Li, Xiang

    2015-01-01

    In this paper, two novel speed compensation algorithms for ISAR imaging under a low signal-to-noise ratio (SNR) condition have been proposed, which are based on the cubic phase function (CPF) and the integrated cubic phase function (ICPF), respectively. These two algorithms can estimate the speed of the target from the wideband radar echo directly, which breaks the limitation of speed measuring in a radar system. With the utilization of non-coherent accumulation, the ICPF-based speed compensation algorithm is robust to noise and can meet the requirement of speed compensation for ISAR imaging under a low SNR condition. Moreover, a fast searching implementation strategy, which consists of coarse search and precise search, has been introduced to decrease the computational burden of speed compensation based on CPF and ICPF. Experimental results based on radar data validate the effectiveness of the proposed algorithms. PMID:26225980

  6. Rigorous comparison of the spectral SNR of FTIR and EC-QCL spectroscopy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Childs, David T. D.; Hogg, Richard A.; Groom, Kristian M.; Revin, Dmitry G.; Rehman, Ihtesham U.; Cockburn, John W.; Matcher, Stephen J.

    2016-03-01

    FTIR spectroscopy using a thermal light source has been the dominant method for obtaining infrared spectra since the 1950's. Unfortunately the limited surface brightness and low spatial coherence of black-body radiators limits the spectral SNR in microspectroscopy and stand-off detection. Two recent innovations are addressing this problem a) FTIR instruments illuminated by high-spatial coherence broad-band supercontinuum sources and b) high spatial coherence narrow-band EC-QCL's. Here we ask whether these two approaches offer equivalent sensitivity. By noting an analogy with near-infrared optical coherence tomography we rigorously show that the high temporal coherence of the EC-QCL brings an additional, very large SNR advantage over an FTIR instrument illuminated by a supercontinuum source under otherwise matched conditions. Specifically if a spectrum containing N points is recorded by both instruments using the same illumination intensity and the same detector noise level, then the EC-QCL can deliver a given spectral SNR in a time xN shorter than the FTIR instrument. This factor can reach x100, potentially even x1000, in realistic applications. We exploit the analogy with OCT further by developing a mid-infrared "swept laser", using commercially available components, in which the tuning rate is much higher than in commercial EC-QCL devices. We use this swept laser to demonstrate the SNR advantage experimentally, using a custom-made EC-QCL spectrometer and PDMS polymer samples. We explore the potential upper limits on spectral acquisition rates, both from the fundamental kinetics of gain build-up in the external cavity and from likely mechanical limits on cavity tuning rates.

  7. SNR enhancement for composite application using multiple Doppler vibrometers based laser ultrasonic propagation imager

    NASA Astrophysics Data System (ADS)

    Truong, Thanh Chung; Lee, Jung Ryul

    2016-09-01

    In recent years, the technology of using laser ultrasonic propagation imaging for damage visualization of composite structures were applied to real-world applications. Among many choices of sensor for the Ultrasonic Propagation Imager, the laser interferometry has several advantages: it is non-invasive, and portable, and with extraordinarily long-range measurement. However, the critical issue with interferometry sensing is its low signal-to-noise ratio (SNR), where the background noise can mask the damage-induced waves and making it impossible to identify the damages, especially in composite structures. In this paper, we propose a hardware-based SNR enhancement technique using multiple Laser Doppler Vibrometers (LDVs). The out-of-plane mode of ultrasonic signals are measured by multiple LDVs at a common sensing point and then averaged in real time. We showed that the SNR enhancement in experiments was consistent with the theoretical prediction, and also the test results showed a clear improvement for damage visualization of structures using Ultrasonic Wave Propagation Imaging and Ultrasonic Wavenumber Imaging algorithms.

  8. Spatial variation of SNR in two- and three dimensional neuro-PET

    SciTech Connect

    Li, H.H.; Votaw, J.R.

    1997-04-01

    A method for region of interest (ROI) evaluation for three-dimensional (3-D) positron emission tomography (PET) in the sinogram space was implemented, according to the fully 3-D filtered back-projection algorithm. With this method, the statistical error in the image that propagates from the Poisson noise in the raw data was computed. The signal-to-noise ratio (SNR) for ROI`s at various locations inside a cylindrical phantom was computed from both scanner data and simulation data and was verified via the standard deviation method through multiple measurements. As a comparison, two-dimensional (2-D) scans were also collected and similar computations carried out. Results show that the SNR increases with radius due to decreased attenuation at the edge of the phantom. For 3-D scans, the SNR drops gradually for ROI`s outside the central 8 cm of the field of view (FOV). Also, it was found that the random events must be recorded and considered in the error computation.

  9. An Atypical Neon Rich Type 1-a SNR in the SMC: an Astronomical Vegas Strip?

    NASA Astrophysics Data System (ADS)

    Roper, Quentin; McEntaffer, R. L.

    2011-01-01

    Supernova Remnant (SNR) 0104-72.3 is a highly asymmetric SNR discovered in the Small Magellanic Cloud. Its metallicity-poor environment led Hughes and Smith et al. (1994) to conclude that 0104-72.3 was formed by a Type 2 supernova. However, in a recent Chandra observation, Fe-L emission was identified in the spectrum of 0104-72.3, and, when combined with its asymmetry, led Park et al. to conclude that 0104-72.3 was formed by a Type 1-a supernova. We, through this presentation, will support the findings of Park et al., and also introduce new results in the discovery of Ne IX ejecta emission, which is inconsistent with many of the extant explosion models of Type I-a supernovae. We will discuss the atypical nature of this SNR's birth, including the possibility of a doubly-degenerate merger of C-O white dwarves, or the possibility that this was formed by accretion onto an O-Ne-Mg white dwarf.

  10. GNSS-SNR-derived water surface heights based on Newton Interval Analysis

    NASA Astrophysics Data System (ADS)

    Reinking, Jörg

    2016-04-01

    The power of Global navigation satellite system (GNSS) signals is commonly recorded as signal-to-noise ratio (SNR) by GNSS receivers. SNR mainly depends on the direct signal but also on the reflected signal. Hence the analysis of SNR data allows the computation of heights of the reflecting surfaces by means of interference pattern technique (IPT). In classical IPT the distance between the antenna and the reflector is derived from the multipath pattern using a Lomb-Scargle Periodogram (LSP) analysis which is calculated separately for every satellite involved. The final reflector height is later estimated combining all those results A more sophisticated approach uses a consistent computation of the reflector height from all observations of all satellites in a single estimation step. This is achieved by replacing LSP analysis by an appropriate common least squares adjustment for all satellites. The sum of squares of residuals from such an adjustment depends on the reflector height and is used as an objective function. The reflector height is than derived in a global optimization process based on interval analysis. This approach additionally reduces the computational efforts compared to LSP. For a constant or only slowly changing reflector height, the height could be treated at least as a quasi-static non-time-depending function for a particular time window. In this one-dimensional case the global optimization can be carried out based on the Interval Newton Method. The method is demonstrated using a data set obtain from a measurement on the Weser river, Germany.

  11. Tracking performance of the polarity-type costas loop at low SNR for UQPSK signal. [Unbalanced Quadri-PSK

    NASA Technical Reports Server (NTRS)

    Park, Y. H.

    1981-01-01

    Carrier tracking performance of the polarity type costas loop is analyzed for unbalanced quadriphase-shift-keyed (UQPSK) signals at low SNR. Squaring losses for various SNR, IF bandwidth, and data rate ratios are presented. The RMS phase jitter for a particular loop is computed for various I and Q channel power and data rate ratios. Experimental results using a breadboard costas loop are also included.

  12. Empirical Evaluation of a New Method for Calculating Signal to Noise Ratio (SNR) for Microarray Data Analysis

    SciTech Connect

    Zhou, Jizhong; He, Zhili; Zhou, Jizhong

    2008-03-06

    Signal-to-noise-ratio (SNR) thresholds for microarray data analysis were experimentally determined with an oligonucleotide array that contained perfect match (PM) and mismatch (MM) probes based upon four genes from Shewanella oneidensis MR-1. A new SNR calculation, called signal to both standard deviations ratio (SSDR) was developed, and evaluated along with other two methods, signal to standard deviation ratio (SSR), and signal to background ratio (SBR). At a low stringency, the thresholds of SSR, SBR, and SSDR were 2.5, 1.60 and 0.80 with oligonucleotide and PCR amplicon as target templates, and 2.0, 1.60 and 0.70 with genomic DNA as target templates. Slightly higher thresholds were obtained at the high stringency condition. The thresholds of SSR and SSDR decreased with an increase in the complexity of targets (e.g., target types), and the presence of background DNA, and a decrease in the composition of targets, while SBR remained unchanged under all situations. The lowest percentage of false positives (FP) and false negatives (FN) was observed with the SSDR calculation method, suggesting that it may be a better SNR calculation for more accurate determination of SNR thresholds. Positive spots identified by SNR thresholds were verified by the Student t-test, and consistent results were observed. This study provides general guidance for users to select appropriate SNR thresholds for different samples under different hybridization conditions.

  13. Effects of WDRC release time and number of channels on output SNR and speech recognition

    PubMed Central

    Alexander, Joshua M.; Masterson, Katie

    2014-01-01

    Objectives The purpose of this study was to investigate the joint effects that wide dynamic range compression (WDRC) release time (RT) and number of channels have on recognition of sentences in the presence of steady and modulated maskers at different signal-to-noise ratios (SNRs). How the different combinations of WDRC parameters affect output SNR and the role this plays in the observed findings was also investigated. Design Twenty-four listeners with mild to moderate sensorineural hearing loss identified sentences mixed with steady or modulated maskers at 3 SNRs (−5, 0, +5 dB) that had been processed using a hearing aid simulator with 6 combinations of RT (40 and 640 ms) and number of channels (4, 8, and 16). Compression parameters were set using the Desired Sensation Level v5.0a prescriptive fitting method. For each condition, amplified speech and masker levels and the resultant long-term output SNR were measured. Results Speech recognition with WDRC depended on the combination of RT and number of channels, with the greatest effects observed at 0 dB input SNR, in which mean speech recognition scores varied by 10–12% across WDRC manipulations. Overall, effect sizes were generally small. Across both masker types and the three SNRs tested, the best speech recognition was obtained with 8 channels, regardless of RT. Increased speech levels, which favor audibility, were associated with the short RT and with an increase in the number of channels. These same conditions also increased masker levels by an even greater amount, for a net decrease in the long-term output SNR. Changes in long-term SNR across WDRC conditions were found to be strongly associated with changes in the temporal envelope shape as quantified by the Envelope Difference Index, however, neither of these factors fully explained the observed differences in speech recognition. Conclusions A primary finding of this study was that the number of channels had a modest effect when analyzed at each level of

  14. Intelligibility for Binaural Speech with Discarded Low-SNR Speech Components.

    PubMed

    Schoenmaker, Esther; van de Par, Steven

    2016-01-01

    Speech intelligibility in multitalker settings improves when the target speaker is spatially separated from the interfering speakers. A factor that may contribute to this improvement is the improved detectability of target-speech components due to binaural interaction in analogy to the Binaural Masking Level Difference (BMLD). This would allow listeners to hear target speech components within specific time-frequency intervals that have a negative SNR, similar to the improvement in the detectability of a tone in noise when these contain disparate interaural difference cues. To investigate whether these negative-SNR target-speech components indeed contribute to speech intelligibility, a stimulus manipulation was performed where all target components were removed when local SNRs were smaller than a certain criterion value. It can be expected that for sufficiently high criterion values target speech components will be removed that do contribute to speech intelligibility. For spatially separated speakers, assuming that a BMLD-like detection advantage contributes to intelligibility, degradation in intelligibility is expected already at criterion values below 0 dB SNR. However, for collocated speakers it is expected that higher criterion values can be applied without impairing speech intelligibility. Results show that degradation of intelligibility for separated speakers is only seen for criterion values of 0 dB and above, indicating a negligible contribution of a BMLD-like detection advantage in multitalker settings. These results show that the spatial benefit is related to a spatial separation of speech components at positive local SNRs rather than to a BMLD-like detection improvement for speech components at negative local SNRs. PMID:27080648

  15. IKT 16: the first X-ray confirmed composite SNR in the SMC

    NASA Astrophysics Data System (ADS)

    Maitra, C.; Ballet, J.; Filipović, M. D.; Haberl, F.; Tiengo, A.; Grieve, K.; Roper, Q.

    2015-12-01

    Aims: IKT 16 is an X-ray and radio-faint supernova remnant (SNR) in the Small Magellanic Cloud (SMC). A detailed X-ray study of this SNR with XMM-Newton confirmed the presence of a hard X-ray source near its centre, indicating the detection of the first composite SNR in the SMC. With a dedicated Chandra observation we aim to resolve the point source and confirm its nature. We also acquire new ATCA observations of the source at 2.1 GHz with improved flux density estimates and resolution. Methods: We perform detailed spatial and spectral analysis of the source. With the highest resolution X-ray and radio image of the centre of the SNR available today, we resolve the source and confirm its pulsar wind nebula (PWN) nature. Further, we constrain the geometrical parameters of the PWN and perform spectral analysis for the point source and the PWN separately. We also test for the radial variations of the PWN spectrum and its possible east west asymmetry. Results: The X-ray source at the centre of IKT 16 can be resolved into a symmetrical elongated feature centring a point source, the putative pulsar. Spatial modelling indicates an extent of 5.2'' of the feature with its axis inclined at 82° east from north, aligned with a larger radio feature consisting of two lobes almost symmetrical about the X-ray source. The picture is consistent with a PWN which has not yet collided with the reverse shock. The point source is about three times brighter than the PWN and has a hard spectrum of spectral index 1.1 compared to a value 2.2 for the PWN. This points to the presence of a pulsar dominated by non-thermal emission. The expected Ė is ~1037 erg s-1 and spin period <100 ms. However, the presence of a compact nebula unresolved by Chandra at the distance of the SMC cannot completely be ruled out. The reduced images (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/584/A

  16. VizieR Online Data Catalog: The first Fermi LAT SNR catalog (1SC) (Acero+, 2016)

    NASA Astrophysics Data System (ADS)

    Acero, F.; Ackermann, M.; Ajello, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bonino, R.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caputo, R.; Caragiulo, M.; Caraveo, P. A.; Casandjian, J. M.; Cavazzuti, E.; Cecchi, C.; Chekhtman, A.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; Cohen, J. M.; Cohen-Tanugi, J.; Cominsky, L. R.; Condon, B.; Conrad, J.; Cutini, S.; D'Ammando, F.; de Angelis, A.; de Palma, F.; Desiante, R.; Digel, S. W.; di Venere, L.; Drell, P. S.; Drlica-Wagner, A.; Favuzzi, C.; Ferrara, E. C.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Gomez-Vargas, G. A.; Grenier, I. A.; Grondin, M.-H.; Guillemot, L.; Guiriec, S.; Gustafsson, M.; Hadasch, D.; Harding, A. K.; Hayashida, M.; Hays, E.; Hewitt, J. W.; Hill, A. B.; Horan, D.; Hou, X.; Iafrate, G.; Jogler, T.; Johannesson, G.; Johnson!, A. S.; Ka, Mae T.; Katagiri, H.; Kataoka, J.; Katsuta, J.; Kerr, M.; Knodlseder, J.; Kocevski, D.; Kuss, M.; Laffon, H.; Lande, J.; Larsson, S.; Latronico, L.; Lemoine-Goumard, M.; Li, J.; Li, L.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Magill, J.; Maldera, S.; Marelli, M.; Mayer, M.; Mazziotta, M. N.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nemmen, R.; Nuss, E.; Ohsugi, T.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Perkins, J. S.; Pesce-Rollins, M.; Petrosian, V.; Piron, F.; Pivato, G.; Porter, T. A.; Raino, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Renaud, M.; Reposeur, T.; Rousseau, R.; Saz Parkinson, P. M.; Schmid, J.; Schulz, A.; Sgro, C.; Siskind, E. J.; Spada, F.; Spandre, G.; Spinelli, P.; Strong, A. W.; Suson, D. J.; Tajima, H.; Takahashi, H.; Tanaka, T.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Tibolla, O.; Torres, D. F.; Tosti, G.; Troja, E.; Uchiyama, Y.; Vianello, G.; Wells, B.; Wood, K. S.; Wood, M.; Yassine, M.; Den Hartog P. R.; Zimmer, S.

    2016-06-01

    We have systematically characterized the Fermi/LAT 1-100GeV emission from 36 months (from 2008 August 4 to 2011 August 4) in 279 regions containing known radio SNRs, identifying sources emitting in the regions and then determining the likelihood that the source nearest the SNR is associated with it. We found 102 candidates, 30 of which have sufficient spatial overlap and significance with the alternative IEMs to suggest they are the GeV counterparts to their corresponding radio SNRs and an additional 14 candidates which may also be related to the SNRs. (3 data files).

  17. SPR sensors in POF: a new experimental configuration for extended refractive index range and better SNR

    NASA Astrophysics Data System (ADS)

    Cennamo, N.; Coelho, L.; Guerreiro, A.; Jorge, P. A. S.; Zeni, L.

    2014-05-01

    In this work we present a new low cost SPR (Surface Plasmon Resonance) sensor configuration based on efficient higher-order mode filtering in plastic multimode fibers, using a tapered POF (Plastic Optical Fiber) after the sensor system, without decreasing the sensitivity of the sensor. In particular, we present the experimental results obtained with this new configuration. The experimental results have shown as the tapered POF after the sensor system influences the performances in terms of refractive index range and Signal-to-Noise Ratio (SNR).

  18. XMM-Newton observation of SNR J0533-7202 in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Kavanagh, P. J.; Sasaki, M.; Whelan, E. T.; Maggi, P.; Haberl, F.; Bozzetto, L. M.; Filipović, M. D.; Crawford, E. J.

    2015-07-01

    Aims: We present an X-ray study of the supernova remnant SNR J0533-7202 in the Large Magellanic Cloud (LMC) and determine its physical characteristics based on its X-ray emission. Methods: We observed SNR J0533-7202 with XMM-Newton (background flare-filtered exposure times of 18 ks EPIC-pn and 31 ks EPIC-MOS1, EPIC-MOS2). We produced X-ray images of the supernova remnant, performed an X-ray spectral analysis, and compared the results to multi-wavelength studies. Results: The distribution of X-ray emission is highly non-uniform, with the south-west region much brighter than the north-east. The detected X-ray emission is correlated with the radio emission from the remnant. We determine that this morphology is most likely due to the supernova remnant expanding into a non-uniform ambient medium and not an absorption effect. We estimate the remnant size to be 53.9 (±3.4) × 43.6 (±3.4) pc, with the major axis rotated ~64° east of north. We find no spectral signatures of ejecta emission and infer that the X-ray plasma is dominated by swept up interstellar medium. Using the spectral fit results and the Sedov self-similar solution, we estimate the age of SNR J0533-7202 to be ~17-27 kyr, with an initial explosion energy of (0.09-0.83) × 1051 erg. We detected an X-ray source located near the centre of the remnant, namely XMMU J053348.2-720233. The source type could not be conclusively determined due to the lack of a multi-wavelength counterpart and low X-ray counts. We found that it is likely either a background active galactic nucleus or a low-mass X-ray binary in the LMC. Conclusions: We detected bright thermal X-ray emission from SNR J0533-7202 and determined that the remnant is in the Sedov phase of its evolution. The lack of ejecta emission prohibits us from typing the remnant with the X-ray data. Therefore, the likely Type Ia classification based on the local stellar population and star formation history reported in the literature cannot be improved upon. Based on

  19. Markov random field based automatic alignment for low SNR imagesfor cryo electron tomography

    SciTech Connect

    Amat, Fernando; Moussavi, Farshid; Comolli, Luis R.; Elidan, Gal; Horowitz, Mark

    2007-07-21

    We present a method for automatic full precision alignmentof the images in a tomographic tilt series. Full-precision automaticalignment of cryo electron microscopy images has remained a difficultchallenge to date, due to the limited electron dose and low imagecontrast. These facts lead to poor signal to noise ratio (SNR) in theimages, which causes automatic feature trackers to generate errors, evenwith high contrast gold particles as fiducial features. To enable fullyautomatic alignment for full-precision reconstructions, we frame theproblem probabilistically as finding the most likely particle tracksgiven a set of noisy images, using contextual information to make thesolution more robust to the noise in each image. To solve this maximumlikelihood problem, we use Markov Random Fields (MRF) to establish thecorrespondence of features in alignment and robust optimization forprojection model estimation. The resultingalgorithm, called RobustAlignment and Projection Estimation for Tomographic Reconstruction, orRAPTOR, has not needed any manual intervention for the difficult datasets we have tried, and has provided sub-pixel alignment that is as goodas the manual approach by an expert user. We are able to automaticallymap complete and partial marker trajectories and thus obtain highlyaccurate image alignment. Our method has been applied to challenging cryoelectron tomographic datasets with low SNR from intact bacterial cells,as well as several plastic section and x-ray datasets.

  20. Digital test signal generation: An accurate SNR calibration approach for the DSN

    NASA Technical Reports Server (NTRS)

    Gutierrez-Luaces, Benito O.

    1993-01-01

    In support of the on-going automation of the Deep Space Network (DSN) a new method of generating analog test signals with accurate signal-to-noise ratio (SNR) is described. High accuracy is obtained by simultaneous generation of digital noise and signal spectra at the desired bandwidth (base-band or bandpass). The digital synthesis provides a test signal embedded in noise with the statistical properties of a stationary random process. Accuracy is dependent on test integration time and limited only by the system quantization noise (0.02 dB). The monitor and control as well as signal-processing programs reside in a personal computer (PC). Commands are transmitted to properly configure the specially designed high-speed digital hardware. The prototype can generate either two data channels modulated or not on a subcarrier, or one QPSK channel, or a residual carrier with one biphase data channel. The analog spectrum generated is on the DC to 10 MHz frequency range. These spectra may be up-converted to any desired frequency without loss on the characteristics of the SNR provided. Test results are presented.

  1. Improving detection of low SNR targets using moment-based detection

    NASA Astrophysics Data System (ADS)

    Young, Shannon R.; Steward, Bryan J.; Hawks, Michael; Gross, Kevin C.

    2016-05-01

    Increases in the number of cameras deployed, frame rate, and detector array sizes have led to a dramatic increase in the volume of motion imagery data that is collected. Without a corresponding increase in analytical manpower, much of the data is not analyzed to full potential. This creates a need for fast, automated, and robust methods for detecting signals of interest. Current approaches fall into two categories: detect-before-track (DBT), which are fast but often poor at detecting dim targets, and track-before-detect (TBD) methods which can offer better performance but are typically much slower. This research seeks to contribute to the near real time detection of low SNR, unresolved moving targets through an extension of earlier work on higher order moments anomaly detection, a method that exploits both spatial and temporal information but is still computationally efficient and massively parallelizable. It was found that intelligent selection of parameters can improve probability of detection by as much as 25% compared to earlier work with higherorder moments. The present method can reduce detection thresholds by 40% compared to the Reed-Xiaoli anomaly detector for low SNR targets (for a given probability of detection and false alarm).

  2. Improving GNSS-R sea level determination through inverse modeling of SNR data

    NASA Astrophysics Data System (ADS)

    Strandberg, Joakim; Hobiger, Thomas; Haas, Rüdiger

    2016-08-01

    This paper presents a new method for retrieving sea surface heights from Global Navigation Satellite Systems reflectometry (GNSS-R) data by inverse modeling of SNR observations from a single geodetic receiver. The method relies on a B-spline representation of the temporal sea level variations in order to account for its continuity. The corresponding B-spline coefficients are determined through a nonlinear least squares fit to the SNR data, and a consistent choice of model parameters enables the combination of multiple GNSS in a single inversion process. This leads to a clear increase in precision of the sea level retrievals which can be attributed to a better spatial and temporal sampling of the reflecting surface. Tests with data from two different coastal GNSS sites and comparison with colocated tide gauges show a significant increase in precision when compared to previously used methods, reaching standard deviations of 1.4 cm at Onsala, Sweden, and 3.1 cm at Spring Bay, Tasmania.

  3. Multifrequency Radio Observations of SNR J0536-6735 (N 59B) with Associated Pulsar

    NASA Astrophysics Data System (ADS)

    Bozzetto, L. M.; Filipovic, M. D.; Crawford, E. J.; De Horta, A. Y.; Stupar, M.

    2012-06-01

    We present a study of new Australian Telescope Compact Array (ATCA) observations of supernova remnant, SNR J0536-6735. This remnant appears to follow a shell morphology with a diameter of D=36×29 pc (with 1 pc uncertainty in each direction). There is an embedded HII region on the northern limb of the remnant which made various analysis and measurements (such as flux density, spectral index and polarisation) difficult. The radio-continuum emission followed the same structure as the optical emission, allowing for extent and flux density estimates at 20 cm. We estimate the surface brightness at 1 GHz of 2.55×10^{-21} Wm^{-2} Hz^{-1} sr^{-1} for the SNR. Also, we detect a distinctive radio-continuum point source which confirms the previous suggestion of this remnant being associated with pulsar wind nebula (PWN). The tail of this remnant is not seen in the radio-continuum images and is only seen in the optical and X-ray images.

  4. HESS J1640-465 - an exceptionally luminous TeV gamma-ray SNR

    NASA Astrophysics Data System (ADS)

    Eger, Peter; Ohm, Stefan

    HESS J1640-465 is among the brightest Galactic TeV gamma-ray sources ever discovered by the High Energy Stereoscopic System (H.E.S.S.). Its likely association with the shell-type supernova remnant (SNR) G338.3-0.0 at a distance of ˜10 kpc makes it the most luminous Galactic source in the TeV regime. Our recent analysis of follow-up observations with H.E.S.S. reveal a significantly extended TeV morphology with a substantial overlap with the northern part of the SNR shell. Furthermore, the source features a seamless powerlaw spectrum over four orders of magnitude from GeV to TeV energies, with a spectral index of Gamma = 2.15± 0.10_mathrm{stat}± 0.10_mathrm{sys} and a cut-off energy of E_c = 7.3(+2.5}_{-1.8) TeV. These new spectral and morphological results suggest that a significant fraction of the TeV emission is likely of hadronic origin where the product of total proton energy and mean target density could be as high as W_p n_H ˜ 4 × 10(52}(d/10mathrm{kpc) )(2) erg cm(-3) . This would make HESS J1640-465 one of the most extreme and efficient Galactic particle accelerators.

  5. Is Cir X-1 associated with SNR G321.9- 0.3?

    NASA Astrophysics Data System (ADS)

    Mignani, Roberto

    2000-07-01

    Cir X-1 is one of the most intriguing galactic X-ray sources. It is a ~ 16.6 d variable X/radio source, a type I X-ray burster and a QPO emitter, which, in spite of an ambiguous optical counterpart classification, identify it as an LMXB. The source is embedded in a radio nebula, with finer structures protruding towards the centre of the nearby SNR G321.9-0.3. This prompted the speculation about a connection between the two, with Cir X-1 being a runaway binary originated from the supernova explosion. In this case, a a significant proper motion would be expected for Cir X-1. Since this source has been already imaged by HST in 1992, one more WFPC2 image could allow to measure its proper motion in the expected direction. This, together with securing the association with the SNR, will constrain the age of the neutron star in Cir X-1, crucial to trace its magnetic field evolution in an accretion regime and to provide observational inputs to theoretical models. , bf This is a case where a single, very simple, and short observation can greatly contribute to solve an important astrophysical issue.

  6. Improving SNR of fiber Bragg grating sensor by digital signal processing

    NASA Astrophysics Data System (ADS)

    Ning, Jing; Yang, Shangming; Zhang, Yan; Cui, Hong-liang

    2007-09-01

    Traditionally, the broadband amplified spontaneous emission (ASE) source is considered to be used as the light source for the fiber Bragg grating (FBG) sensing technology. However, this kind of light source has some disadvantages - the huge volume and the high power consumption. These shortages will hamper the development of FBG sensing technology in some kind of applications such as unattended sensor and space environment. In this paper, the authors will present a new approach, the usage of the light emitted diode (LED) as the light source. The LED source is very compact, easy to integrate, and significantly reduced the cost and power consumption. But the light density of LED is so weak that the useful signal is almost buried by noise. A solution proposed by our group is to enhance SNR by digital signal processing (DSP) technology, including high frequency modulation, phase-lock amplifier, encoding on LED and decoding on the synchronistic detection. The experimental results show our effort could significantly increases the signal noise ratio (SNR) and make FBG sensor practical on application.

  7. The Northern Rims of SNR RCW 86 - Chandra's Recent Observations and their Implications for Particle Acceleration

    NASA Astrophysics Data System (ADS)

    Castro, D.

    2016-06-01

    The Chandra observations towards the northwest (NW) and northeast (NE) rims of supernova remnant (SNR) RCW 86 reveal great detail about the characteristics of the shocks, particle acceleration and the local environments in these 2 distinct regions. Both the NW and NE of RCW 86 show clear evidence of non-thermal X-ray emission, identified as synchrotron radiation from shock-accelerated electrons with TeV energies, interacting with the compressed, and probably amplified, local magnetic field. Magnetic field amplification (MFA) is broadly believed to result from, and contribute to, cosmic ray acceleration at the shocks of SNRs. However, we still lack a detailed understanding of the particle acceleration mechanism, and with this study we address the connection between the shock properties and ambient medium with MFA. The Chandra observations of RCW 86 allowed us to constrain the magnitude of the post-shock magnetic field in the NE and NW rims by deriving synchrotron filament widths, and also the densities in these regions, using thermal emission co-located with the non-thermal rims. I will discuss our analysis in detail and comment on how MFA appears to be related to certain characteristics of the SNR shock.

  8. SNR Loss: A new objective measure for predicting speech intelligibility of noise-suppressed speech

    PubMed Central

    Ma, Jianfen; Loizou, Philipos C.

    2010-01-01

    Most of the existing intelligibility measures do not account for the distortions present in processed speech, such as those introduced by speech-enhancement algorithms. In the present study, we propose three new objective measures that can be used for prediction of intelligibility of processed (e.g., via an enhancement algorithm) speech in noisy conditions. All three measures use a critical-band spectral representation of the clean and noise-suppressed signals and are based on the measurement of the SNR loss incurred in each critical band after the corrupted signal goes through a speech enhancement algorithm. The proposed measures are flexible in that they can provide different weights to the two types of spectral distortions introduced by enhancement algorithms, namely spectral attenuation and spectral amplification distortions. The proposed measures were evaluated with intelligibility scores obtained by normal-hearing listeners in 72 noisy conditions involving noise-suppressed speech (consonants and sentences) corrupted by four different maskers (car, babble, train and street interferences). Highest correlation (r=−0.85) with sentence recognition scores was obtained using a variant of the SNR loss measure that only included vowel/consonant transitions and weak consonant information. High correlation was maintained for all noise types, with a maximum correlation (r=−0.88) achieved in street noise conditions. PMID:21503274

  9. [Analysis and experimental verification of SNR for a far ultraviolet imaging spectrograph in 115-180 nm].

    PubMed

    Yu, Lei; Lin, Guan-yu; Qu, Yi; Wang, Shu-rong

    2010-11-01

    An 115-180 nm far ultraviolet limb imaging spectrograph prototype was developed for the detection of the ionosphere. For the particularity of the wavelength band in far ultraviolet, the signals accepted by the instrument are very weak. So the sensitivity and signal-noise-ratio (SNR) are two important performance parameters for the spectrograph. In the present paper, based on the signal statistical detection theory and the threshold detection theory, a method for calculation of the sensitivity and SNR has been proposed. Firstly, the probabilities of the accepted signals and system noises were analyzed. Secondly, the mathematical expressions of sensitivity and SNR of the instrument were deduced by introducing the detection probability factor and the false alarm rate factor. Based on the calculation of the sensitivity and the intensity of the particles radiation wavelengths, it was found that the sensitivity can meet the need of the detection. Finally, the SNR of the instrument were analyzed by using the method, and the coherent experiment was built to prove the results. The error of theoretic calculation and experimental results can be accepted. It indicates that the SNR analysis method is feasible. PMID:21284204

  10. A complete radio study of SNR G15.4+0.1 from new GMRT observations

    NASA Astrophysics Data System (ADS)

    Supan, L.; Castelletti, G.; Joshi, B. C.; Surnis, M. P.; Supanitsky, D.

    2015-04-01

    Aims: The supernova remnant (SNR) G15.4+0.1 is considered to be the possible counterpart of the γ-ray source HESS J1818-154. With the goal of getting a complete view of this remnant and understanding the nature of the γ-ray flux, we conducted a detailed radio study that includes the search for pulsations and a model of the broadband emission for the SNR G15.4+0.1/HESS J1818-154 system. Methods: Low-frequency imaging at 624 MHz and pulsar observations at 624 and 1404 MHz towards G15.4+0.1 were carried out with the Giant Metrewave Radio Telescope (GMRT). We correlated the new radio data with observations of the source at X-ray and infrared wavelengths from XMM-Newton and Herschel observatories, respectively. To characterize the neutral hydrogen (HI) medium towards G15.4+0.1, we used data from the Southern Galactic Plane Survey. We modelled the spectral energy distribution (SED) using both hadronic and leptonic scenarios. Results: From the combination of the new GMRT observations with existing data, we derived a continuum spectral index α = -0.62 ± 0.03 for the whole remnant. The local synchrotron spectra of G15.4+0.1, calculated from the combination of the GMRT data with 330 MHz observations from the Very Large Array, tends to be flatter in the central part of the remnant, accompanying the region where the blast wave is impinging molecular gas. No spectral index trace was found indicating the radio counterpart to the pulsar wind nebula proposed from X-ray observations. In addition, the search for radio pulsations yielded negative results. Emission at far-infrared wavelengths is observed in the region where the SNR shock is interacting with dense molecular clumps. We also identified HI features forming a shell that wraps most of the outer border of G15.4+0.1. Characteristic parameters were estimated for the shocked HI gas. We found that either a purely hadronic or leptonic model is compatible with the broadband emission known so far.

  11. Digital test signal generation: An accurate SNR calibration approach for the DSN

    NASA Technical Reports Server (NTRS)

    Gutierrez-Luaces, B. O.

    1991-01-01

    A new method of generating analog test signals with accurate signal to noise ratios (SNRs) is described. High accuracy will be obtained by simultaneous generation of digital noise and signal spectra at a given baseband or bandpass limited bandwidth. The digital synthesis will provide a test signal embedded in noise with the statistical properties of a stationary random process. Accuracy will only be dependent on test integration time with a limit imposed by the system quantization noise (expected to be 0.02 dB). Setability will be approximately 0.1 dB. The first digital SNR generator to provide baseband test signals is being built and will be available in early 1991.

  12. A Detailed Observation of a LMC SNR, DEM L241, with XMM-Newton

    NASA Astrophysics Data System (ADS)

    Bamba, Aya; Ueno, Masaru; Nakajima, Hiroshi; Mori, Koji; Koyama, Katsuji

    We report on an XMM-Newton observation of the supernova remnant (SNR) DEM L241 in the Large Magellanic Cloud. In the soft band image, the emission shows an elongated structure, like a killifish (Head and Tail), with a central point source, named as XMMU J053559.3-673509 (Eye). The Eye's spectrum is well reproduced with a power-law model. The source has neither significant coherent pulsations nor time variabilities. Its luminosity and spectrum remind us that the source might be a pulsar and/or pulsar wind nebula in DEM L241. The spectra of Head and Tail are well reproduced by a non-equilibrium ionization plasma model with over-abundant Ne and under-abundant Fe, suggesting that the progenitor of DEM L241 is a very massive star.

  13. Deep Morphological and Spectral Study of the SNR RCW 86 with Fermi-LAT

    NASA Astrophysics Data System (ADS)

    Ajello, M.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Bissaldi, E.; Bloom, E. D.; Bonino, R.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Bruel, P.; Buehler, R.; Caliandro, G. A.; Cameron, R. A.; Caragiulo, M.; Cavazzuti, E.; Charles, E.; Chekhtman, A.; Ciprini, S.; Cohen-Tanugi, J.; Condon, B.; Costanza, F.; Cutini, S.; D'Ammando, F.; de Palma, F.; Desiante, R.; Di Lalla, N.; Di Mauro, M.; Di Venere, L.; Drell, P. S.; Dubner, G.; Dumora, D.; Duvidovich, L.; Favuzzi, C.; Focke, W. B.; Fusco, P.; Gargano, F.; Gasparrini, D.; Giacani, E.; Giglietto, N.; Glanzman, T.; Green, D. A.; Grenier, I. A.; Guiriec, S.; Hays, E.; Hewitt, J. W.; Hill, A. B.; Horan, D.; Jogler, T.; Jóhannesson, G.; Jung-Richardt, I.; Kensei, S.; Kuss, M.; Larsson, S.; Latronico, L.; Lemoine-Goumard, M.; Li, J.; Li, L.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Magill, J.; Maldera, S.; Manfreda, A.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Negro, M.; Nuss, E.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Perkins, J. S.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Reposeur, T.; Schmid, J.; Schulz, A.; Sgrò, C.; Simone, D.; Siskind, E. J.; Spada, F.; Spandre, G.; Spinelli, P.; Thayer, J. B.; Tibaldo, L.; Torres, D. F.; Tosti, G.; Troja, E.; Uchiyama, Y.; Vianello, G.; Vink, J.; Wood, K. S.; Yassine, M.

    2016-03-01

    RCW 86 is a young supernova remnant (SNR) showing a shell-type structure at several wavelengths and is thought to be an efficient cosmic-ray (CR) accelerator. Earlier Fermi Large Area Telescope results reported the detection of γ-ray emission coincident with the position of RCW 86 but its origin (leptonic or hadronic) remained unclear due to the poor statistics. Thanks to 6.5 years of data acquired by the Fermi-LAT and the new event reconstruction Pass 8, we report the significant detection of spatially extended emission coming from RCW 86. The spectrum is described by a power-law function with a very hard photon index ({{Γ }}=1.42+/- {0.1}{{stat}}+/- {0.06}{{syst}}) in the 0.1-500 GeV range and an energy flux above 100 MeV of (2.91+/- {0.8}{{stat}}+/- {0.12}{{syst}}) × {10}-11 erg cm-2 s-1. Gathering all the available multiwavelength (MWL) data, we perform a broadband modeling of the nonthermal emission of RCW 86 to constrain parameters of the nearby medium and bring new hints about the origin of the γ-ray emission. For the whole SNR, the modeling favors a leptonic scenario in the framework of a two-zone model with an average magnetic field of 10.2 ± 0.7 μG and a limit on the maximum energy injected into protons of 2 × 1049 erg for a density of 1 cm-3. In addition, parameter values are derived for the north-east and south-west (SW) regions of RCW 86, providing the first indication of a higher magnetic field in the SW region.

  14. Observations of the Monoceros SNR/Rosette nebula interacting region with the HEGRA system of IACTs

    NASA Astrophysics Data System (ADS)

    Lucarelli, F.; Konopelko, A.; Fonseca, V.; HEGRA Collaboration

    2001-08-01

    The array of 5 imaging atmospheric ˇCerenkov telescopes (IACTs) deployed at La Palma of Canary Island, and operated by the HEGRA (High Energy Gamma Ray Astronomy) collaboration, was used for the observations of the interaction region of the Monoceros SNR with the dense Rosette nebula for a total of about 120 hrs and 20 hrs in ONsource and OFF-source mode, respectively. At present the performance of the IACTs array reveals the energy threshold of 500 GeV and the angular resolution of 0.1° for γrays. Using the HEGRA system of IACTs of rather large field of view (4.3 degree in diameter), we have mapped the extended sky region of 2° × 2° associated with the Monoceros SNR/Rosette nebula and which is centered towards the hard spectrum X-ray point source SAX J0635+533. The EGRET unidentified source of diffuse γ-ray emission (3EG J0634+0521) observed in the energy range between 100 MeV 10 GeV, was effectively in the field of view of our present observations. Based on the Monte Carlo simulations and real data we have studied the response of the IACTs array over its 5 · 10-3 str field of view with respect to the cosmic rays and diffuse γ-ray emission. We have derived a normalization function which takes into account the slightly non uniform sensitivity to the γ-ray fluxes (with the variation of 10%) within the angular distance of 1 deg from the joint optical axis of the telescopes' array after the analysis by mean scaled Width. Here we present the result of the data analysis and its physical interpretation. Correspondence to: F. Lucarelli (Fabrizio.Lucarelli@mpi-hd.mpg.de)

  15. NOTE: The utility of pelvic coil SNR testing in the quality assurance of a clinical MRgFUS system

    NASA Astrophysics Data System (ADS)

    Gorny, Krzysztof R.; Hangiandreou, Nicholas J.; Ward, Heidi A.; Hesley, Gina K.; Brown, Douglas L.; Felmlee, Joel P.

    2009-04-01

    During MRI-guided focused ultrasound (MRgFUS) treatments of uterine fibroids using ExAblate®2000, tissue ablations are delivered by a FUS transducer while MR imaging is performed with a pelvic receiver coil. The consistency of the pelvic coil performance is crucial for reliable MR temperature measurements as well as detailed anatomic imaging in patients. Test sonications in a gel phantom combined with MR thermometry are used to test the performance of the FUS transducer prior to each treatment. As we show, however, these tests do not adequately evaluate receiver coil performance prior to clinical use. This could become a problem since the posterior part of the coil is frequently moved and can malfunction. The aim of this work is to demonstrate the utility of the signal-to-noise ratio (SNR) as a reliable indicator of pelvic coil performance. Slight modification of the vendor-provided coil support was accomplished to assure reproducible coil positioning. The SNR was measured in a gel phantom using axial acquisitions from the 3D-localizer scan. MR temperature and SNR measurements were obtained using a degraded receiver coil (with posterior element removed) and a known faulty coil, and compared to those obtained with a fully functioning coil. While the MR temperature-based tests were insensitive to change in pelvic coil performance, (degraded, p = 0.24; faulty, p = 0.28), the SNR tests were highly sensitive to coil performance, (degraded, p < 0.001; faulty, p < 0.001). Additional clinical data illustrate the utility of SNR testing of the receiver coil. These tests require minimal (or possibly no) additional scan time and have proven to be effective in our clinical practice.

  16. Telemetry SNR improvement using the DSN Advanced Receiver with results for Pioneer 10

    NASA Technical Reports Server (NTRS)

    Hurd, W. J.; Brown, D. H.; Vilnrotter, V. A.; Wiggins, J. D.

    1988-01-01

    A series of tracking tests was conducted in the spring of 1987 to demonstrate the reduced tracking threshold and the improved telemetry singal-to-noise-ratio performance of the DSN Advanced Receiver compared to current operational DSN systems. The Pioneer 10 spacecraft, which is now out of the solar system, was tracked on foud days. The Advanced Receiver achieved an improvement in telemetry SNR of 1 to 1.5 dB over the operational system. It was demonstrated that the spacecraft carrier signal is stable enough for tracking with a receiver carrier loop bandwidth of 0.5 Hz in the one-way mode and 0.1 Hz in the three-way mode, and that the Advanced Receiver is stable at 0.1 Hz. This reduces tracking threshold by 10 to 15 dB compared to current receivers, which have minimum loop bandwidths of 1 to 3 Hz. Thus, the Advanced Receiver will enable tracking of the Pioneer 10 spacecraft until its power source fails, circa 2000, which would not be possible with the current DSN system.

  17. Optimizing binary phase and amplitude filters for PCE, SNR, and discrimination

    NASA Technical Reports Server (NTRS)

    Downie, John D.

    1992-01-01

    Binary phase-only filters (BPOFs) have generated much study because of their implementation on currently available spatial light modulator devices. On polarization-rotating devices such as the magneto-optic spatial light modulator (SLM), it is also possible to encode binary amplitude information into two SLM transmission states, in addition to the binary phase information. This is done by varying the rotation angle of the polarization analyzer following the SLM in the optical train. Through this parameter, a continuum of filters may be designed that span the space of binary phase and amplitude filters (BPAFs) between BPOFs and binary amplitude filters. In this study, we investigate the design of optimal BPAFs for the key correlation characteristics of peak sharpness (through the peak-to-correlation energy (PCE) metric), signal-to-noise ratio (SNR), and discrimination between in-class and out-of-class images. We present simulation results illustrating improvements obtained over conventional BPOFs, and trade-offs between the different performance criteria in terms of the filter design parameter.

  18. Modeling post-explosion anisotropies of ejecta in SNR Cassiopeia A

    NASA Astrophysics Data System (ADS)

    Orlando, S.; Miceli, M.; Pumo, M.; Bocchino, F.

    2016-06-01

    Supernova remnats (SNRs) show a complex morphology characterized by an inhomogeneous spatial distribution of ejecta, believed to reflect pristine structures and features of the progenitor supernova (SN) explosion. Filling the gap between SN explosions and their remnants is very important for a comprehension of the origin of present-day structure of ejecta in SNRs and to probe and constraint current models of SN explosions. The SNR Cassiopeia A (Cas A) is an attractive laboratory for studying the SNe-SNRs connection, being one of the best studied SNRs for which its 3D structure is known. We present a three-dimensional hydrodynamic model describing the evolution of Cas A from the immediate aftermath of the SN explosion to its expansion through the interstellar medium, taking into account the distribution of element abundances of the ejecta, the back reaction of accelerated cosmic rays at the shock front, and the deviations from equilibrium of ionizazion for the most important elements. We use the model to derive the physical parameters characterizing the SN explosion and reproducing the today morphology of Cas A.

  19. A Charge-Based Low-Power High-SNR Capacitive Sensing Interface Circuit

    PubMed Central

    Peng, Sheng-Yu; Qureshi, Muhammad S.; Hasler, Paul E.; Basu, Arindam; Degertekin, F. L.

    2008-01-01

    This paper describes a low-power approach to capacitive sensing that achieves a high signal-to-noise ratio. The circuit is composed of a capacitive feedback charge amplifier and a charge adaptation circuit. Without the adaptation circuit, the charge amplifier only consumes 1 μW to achieve the audio band SNR of 69.34dB. An adaptation scheme using Fowler-Nordheim tunneling and channel hot electron injection mechanisms to stabilize the DC output voltage is demonstrated. This scheme provides a very low frequency pole at 0.2Hz. The measured noise spectrums show that this slow-time scale adaptation does not degrade the circuit performance. The DC path can also be provided by a large feedback resistance without causing extra power consumption. A charge amplifier with a MOS-bipolar pseudo-resistor feedback scheme is interfaced with a capacitive micromachined ultrasonic transducer to demonstrate the feasibility of this approach for ultrasound applications. PMID:18787650

  20. X-ray emission from charge exchange in the Cygnus Loop SNR

    NASA Astrophysics Data System (ADS)

    Roberts, Shawn R.; Wang, Q. Daniel

    2015-05-01

    The Cygnus Loop has been the focus of substantial debate concerning the contribution of charge exchange (CX) to supernova remnant (SNR) X-ray emission. We take advantage of a distinct feature of CX, enhanced Kα forbidden line emission, and employ the energy centroid of the O VII Kα triplet as a diagnostic. Based on X-ray spectra extracted from an extensive set of Suzaku observations, we measure the energy centroid shifts of the triplet on and off the shock rim of the remnant. We find that enhanced forbidden to resonance line emission exists throughout much of the rim and this enhancement azimuthally correlates with non-radiative Hα filaments, a tracer of strong neutral-plasma interaction in the optical. We also show that alternative mechanisms cannot explain the observed enhancement. These results demonstrate the need to model the CX contribution to the X-ray emission of SNRs, particularly for shocks propagating in a partially neutral medium. Such modelling may be critically important to the correct measurements of the ionization, thermal, and chemical properties of SNRs.

  1. Sociopolitical Analyses.

    ERIC Educational Resources Information Center

    Van Galen, Jane, Ed.; And Others

    1992-01-01

    This theme issue of the serial "Educational Foundations" contains four articles devoted to the topic of "Sociopolitical Analyses." In "An Interview with Peter L. McLaren," Mary Leach presented the views of Peter L. McLaren on topics of local and national discourses, values, and the politics of difference. Landon E. Beyer's "Educational Studies and…

  2. X-ray, optical, and radio properties of the extensive SNR population in M83

    NASA Astrophysics Data System (ADS)

    Blair, W.; Long, S. K.; Winkler, F.; Soria, R.; Kuntz, D. K.; Plucinsky, P. P.; Dopita, A. M.

    2016-06-01

    The nearly face-on spiral galaxy M83 (d=4.6 Mpc) provides a significant opportunity for finding and studying a large and diverse sample of SNRs all at the same distance, given its active star formation, a starburst nuclear region, and at least six SNe since 1923. As the result of a concerted effort involving ground and spaced-based studies at radio (ATCA), optical and NIR (Magellan 6.5m and HST), and X-ray (Chandra) wavelengths, we have identified almost 300 SNRs in M83. Of these, at least 87 and 47 were detected in the X-ray and radio bands. Some 227 of the SNR candidates are within the regions observed in [Fe II] 1.64 microns with HST WFC3/IR, and we detect ∼100 of them, including ~8 in dusty regions where the [Fe II] emission was the primary means of identification. Follow-up ground-based spectroscopy of 99 of the 300 SNRs with Gemini-S and the GMOS instrument shows that essentially all of the SNRs identified in ground-based imaging have the [S II]/Halpha ratios expected of bona fide SNRs, and that most of the SNRs in the sample are “normal ISM-dominated” SNRs, in the sense that the line widths are narrow and the spectra look like radiative shocks. We have studied a number of interesting individual SNRs and historical SNe counterparts, as well as investigating the ensemble population of nearly 300 SNRs to better understand their properties as a group, their evolution, and their impact on their host galaxy. Of particular interest is a set of the smallest diameter (and hence presumably youngest) objects measured with HST, where the 0.04arcsec WFC3-UVIS pixels correspond to ~1 pc. One SNR has very broad emission lines and given its small size, was most likely a SN that occurred during the last century but was missed. A number of the other objects are comparable to the Crab Nebula or Cas A in size, but very few show the high velocities and spectral signatures of ejecta. Rather, their spectra show low velocities and “normal” ISM-dominated emissions, albeit

  3. An XMM Archival Study of the LMC SNR N132D

    NASA Astrophysics Data System (ADS)

    Plucinsky, Paul

    We propose to study the X-ray brightest supernova remnant (SNR) in the Large Magellanic Cloud (LMC) N132D to determine the abundances of the high Z products of nucleosynthesis (Si, S, Ca, Ar,etc.) relative to Fe and compare those values to current models of nucleosynthetic yields. We will also characterize the evolutionary parameters of the SNR (age, initial explosion energy, average initial ambient density) to place this remnant in context with studies of other remnants at different evolutionary stages. We intend to take advantage of the unique opportunity presented by the existing ~900 ks of observations acquired by XMM-Newton over the past 10 years. N132D has been routinely observed as a calibration target but the full scientific potential of these data have yet to be realized. These archival data represent the equivalent of a ``Large Program'' which would be difficult or impossible to acquire under a Guest Observer program. N132D has been extensively studied at other wavelengths and has been classified as an 'O-rich' remnant based on the optical spectra. The abundances derived from the optical suggest the progenitor was a massive star, perhaps as massive as 35 or more solar masses. The detection of only C, O, Ne, Mg, and Si in the ejecta suggest the progenitor may have been a WO Wolf Rayet star with an O rich mantle which did not mix with the deeper layers. The spectra of the bright optical knots do not show any emission from elements with higher Z than Si, yet the nucleosynthesis models predict significant quantities of these higher Z elements. Our preliminary analysis of the deep XMM-Newton data clearly show emission lines from S, Ar, Ca, and Fe, with indications of other possible lines between Ca and Fe. It is clear that the X-ray emitting and optically-emitting gas are probing different regions of the ejecta. Only with a complete characterization of all of the ejecta can a meaningful comparison to nucleosynthesis models be made and conclusions drawn about

  4. Performance of a novel LED lamp arrangement to reduce SNR fluctuation for multi-user visible light communication systems.

    PubMed

    Wang, Zixiong; Yu, Changyuan; Zhong, Wen-De; Chen, Jian; Chen, Wei

    2012-02-13

    This paper investigates the performance of our recently proposed LED lamp arrangement to reduce the SNR fluctuation from different locations in the room for multi-user visible light communications. The LED lamp arrangement consists of 4 LED lamps positioned in the corners and 12 LED lamps spread evenly on a circle. Our studies show that the SNR fluctuation under such a LED lamp arrangement is reduced from 14.5 dB to 0.9 dB, which guarantees that users can obtain almost identical communication quality, regardless of their locations. After time domain zero-forcing (ZF) equalization, the BER performances and channel capacities of 100-Mbit/s and 200-Mbit/s bipolar on-off-keying (OOK) signal with most significant inter-symbol interference (ISI) are very close to that of the channel without any ISI caused by this LED lamp arrangement.

  5. Observations of the radio source G6.6-0.1 positionally coincident with the W28 SNR

    NASA Technical Reports Server (NTRS)

    Andrews, M. D.; Basart, J. P.; Lamb, R. C.

    1985-01-01

    This paper reports scaled-array continuum and H76-alpha line observations of the radio source G6.6-0.1 which is positioned at the center of the W28 SNR. The source exhibits a bright core surrounded by extended emission which appears organized into arcs and wisps. G6.6-0.1 is interpreted as a compact H II region with a unique morphology.

  6. Performance of the split-symbol moments SNR estimator in the presence of inter-symbol interference

    NASA Technical Reports Server (NTRS)

    Shah, B.; Hinedi, S.

    1989-01-01

    The Split-Symbol Moments Estimator (SSME) is an algorithm that is designed to estimate symbol signal-to-noise ratio (SNR) in the presence of additive white Gaussian noise (AWGN). The performance of the SSME algorithm in band-limited channels is examined. The effects of the resulting inter-symbol interference (ISI) are quantified. All results obtained are in closed form and can be easily evaluated numerically for performance prediction purposes. Furthermore, they are validated through digital simulations.

  7. Star Forming Dense Cloud Cores in the TeV -ray SNR RX J1713.7-3946

    SciTech Connect

    Sano, H.; Sato, J.; Yamamoto, H.; Hayakawa, T.; Torii, K.; Moribe, N.; Kawamura, A.; Okuda, T.; Mizuno, N.; Onishi, T.; Maezawa, H.; Inoue, T.; Inutsuka, S.; Tanaka, T.; Mizuno, A.; Ogawa, H.; Stutzki, J.; Bertoldi, F.; Anderl, S.; Bronfman, L.; Koo, B.C.

    2010-10-27

    RX J1713.7-3946 is one of the TeV {gamma}-ray supernova remnants (SNRs) emitting synchrotron X rays. The SNR is associated with molecular gas located at {approx}1 kpc. We made new molecular observations toward the dense cloud cores, peaks A, C and D, in the SNR in the {sup 12}CO(J=2-1) and {sup 13}CO(J=2-1) transitions at angular resolution of 90 degrees. The most intense core in {sup 13}CO, peak C, was also mapped in the {sup 12}CO(J=4-3) transition at angular resolution of 38 degrees. Peak C shows strong signs of active star formation including bipolar outflow and a far-infrared protostellar source and has a steep gradient with a r{sup -2.2 {+-} 0.4} variation in the average density within radius r. Peak C and the other dense cloud cores are rim-brightened in synchrotron X rays, suggesting that the dense cloud cores are embedded within or on the outer boundary of the SNR shell. This confirms the earlier suggestion that the X rays are physically associated with the molecular gas (Fukui et al. 2003). We present a scenario where the densest molecular core, peak C, survived against the blast wave and is now embedded within the SNR. Numerical simulations of the shock-cloud interaction indicate that a dense clump can indeed survive shock erosion, since shock propagation speed is stalled in the dense clump. Additionally, the shock-cloud interaction induces turbulence and magnetic field amplification around the dense clump that may facilitate particle acceleration in the lower-density inter-clump space leading to the enhanced synchrotron X rays around dense cores.

  8. Clinical NECR in 18F-FDG PET scans: optimization of injected activity and variable acquisition time. Relationship with SNR

    NASA Astrophysics Data System (ADS)

    Carlier, T.; Ferrer, L.; Necib, H.; Bodet-Milin, C.; Rousseau, C.; Kraeber-Bodéré, F.

    2014-10-01

    The injected activity and the acquisition time per bed position for 18F-FDG PET scans are usually optimized by using metrics obtained from phantom experiments. However, optimal activity and time duration can significantly vary from a phantom set-up and from patient to patient. An approach using a patient-specific noise equivalent count rate (NECR) modelling has been previously proposed for optimizing clinical scanning protocols. We propose using the clinical NECR on a large population as a function of the body mass index (BMI) for deriving the optimal injected activity and acquisition duration per bed position. The relationship between the NEC and the signal-to-noise ratio (SNR) was assessed both in a phantom and in a clinical setting. 491 consecutive patients were retrospectively evaluated and divided into 4 BMI subgroups. Two criteria were used to optimize the injected activity and the time per bed position was adjusted using the NECR value while keeping the total acquisition time constant. Finally, the relationship between NEC and SNR was investigated using an anthropomorphic phantom and a population of 507 other patients. While the first dose regimen suggested a unique injected activity (665 MBq) regardless of the BMI, the second dose regimen proposed a variable activity and a total acquisition time according to the BMI. The NEC improvement was around 35% as compared with the local current injection rule. Variable time per bed position was derived according to BMI and anatomical region. NEC and number of true events were found to be highly correlated with SNR for the phantom set-up and partially confirmed in the patient study for the BMI subgroup under 28 kg m-2 suggesting that for the scanner, the nonlinear reconstruction algorithm used in this study and BMI < 28 kg m-2, NEC, or the number of true events linearly correlated with SNR2.

  9. High-speed and high-SNR photoacoustic microscopy based on a galvanometer mirror in non-conducting liquid

    NASA Astrophysics Data System (ADS)

    Kim, Jin Young; Lee, Changho; Park, Kyungjin; Han, Sangyeob; Kim, Chulhong

    2016-10-01

    Optical-resolution photoacoustic microscopy (OR-PAM), a promising microscopic imaging technique with high ultrasound resolution and superior optical sensitivity, can provide anatomical, functional, and molecular information at scales ranging from the microvasculature to single red blood cells. In particular, real-time OR-PAM imaging with a high signal-to-noise ratio (SNR) is a prerequisite for widespread use in preclinical and clinical applications. Although several technical approaches have been pursued to simultaneously improve the imaging speed and SNR of OR-PAM, they are bulky, complex, not sensitive, and/or not actually real-time. In this paper, we demonstrate a simple and novel OR-PAM technique which is based on a typical galvanometer immersed in non-conducting liquid. Using an opto-ultrasound combiner, this OR-PAM system achieves a high SNR and fast imaging speed. It takes only 2 seconds to acquire a volumetric image with a wide field of view (FOV) of 4 × 8 mm2 along the X and Y axes, respectively. The measured lateral and axial resolutions are 6.0 and 37.7 μm, respectively. Finally, as a demonstration of the system’s capability, we successfully imaged the microvasculature in a mouse ear in vivo. Our new method will contribute substantially to the popularization and commercialization of OR-PAM in various preclinical and clinical applications.

  10. High-speed and high-SNR photoacoustic microscopy based on a galvanometer mirror in non-conducting liquid

    PubMed Central

    Kim, Jin Young; Lee, Changho; Park, Kyungjin; Han, Sangyeob; Kim, Chulhong

    2016-01-01

    Optical-resolution photoacoustic microscopy (OR-PAM), a promising microscopic imaging technique with high ultrasound resolution and superior optical sensitivity, can provide anatomical, functional, and molecular information at scales ranging from the microvasculature to single red blood cells. In particular, real-time OR-PAM imaging with a high signal-to-noise ratio (SNR) is a prerequisite for widespread use in preclinical and clinical applications. Although several technical approaches have been pursued to simultaneously improve the imaging speed and SNR of OR-PAM, they are bulky, complex, not sensitive, and/or not actually real-time. In this paper, we demonstrate a simple and novel OR-PAM technique which is based on a typical galvanometer immersed in non-conducting liquid. Using an opto-ultrasound combiner, this OR-PAM system achieves a high SNR and fast imaging speed. It takes only 2 seconds to acquire a volumetric image with a wide field of view (FOV) of 4 × 8 mm2 along the X and Y axes, respectively. The measured lateral and axial resolutions are 6.0 and 37.7 μm, respectively. Finally, as a demonstration of the system’s capability, we successfully imaged the microvasculature in a mouse ear in vivo. Our new method will contribute substantially to the popularization and commercialization of OR-PAM in various preclinical and clinical applications. PMID:27708379

  11. Monitoring of the volcanic plume based on the post-fit phase residual of PPP analysis and SNR data

    NASA Astrophysics Data System (ADS)

    Ohta, Yusaku; Iguchi, Masato

    2016-04-01

    A volcanic explosion is one of the largest energy-release phenomena on earth. For example, vulcanian eruptions usually eject large amounts of rock mass, tephra, and volcanic ash. Ash fall from such events can seriously affect the structural integrity of buildings, in addition to disrupting land and air traffic. Therefore, the monitoring and prediction of ash fall is very important. In this study, using data from a dense GNSS network, we investigated the spatiotemporal development of the volcanic plume ejected by the vulcanian eruption in Sakurajima, southwestern Japan on July 24, 2012. We extracted the post-fit phase residuals (PPR) of ionosphere-free linear combinations for each satellite based on the precise point positioning approach. Temporal and spatial PPR anomalies clearly detected the movement of the volcanic plume. The maximum height of the crossing points of anomalous PPR paths was determined to be approximately 4000 m. We then compared the PPR with the signal-to-noise ratio (SNR) anomalies. Only the path passing just above the crater showed significant change in the SNR value, suggesting that the volcanic ash and the water vapor within the volcanic plume became separated after reaching a high altitude because of ash fall during the plume's lateral movement. In the presentation, we will introduce the eruption in Shin-dake (Kuchinoerabu island, southwestern Japan) on May 29, 2015 based on the SNR data.

  12. SPATIAL DISTRIBUTION OF X-RAY EMITTING EJECTA IN TYCHO’S SNR: INDICATIONS OF SHOCKED TITANIUM

    SciTech Connect

    Miceli, M.; Sciortino, S.; Orlando, S.; Troja, E.

    2015-06-01

    Young supernova remnants (SNRs) show characteristic ejecta-dominated X-ray emission that allows us to probe the products of explosive nucleosynthesis processes and to ascertain important information about the physics of supernova explosions. Hard X-ray observations have recently revealed the presence of the radioactive decay lines of {sup 44}Ti at ∼67.9 and ∼78.4 keV in Tycho’s SNR. Here, we analyze a set of XMM-Newton archive observations of Tycho’s SNR. We produce equivalent width (EW) maps of the Fe K and Ca xix emission lines and find indications for a stratification of the abundances of these elements and significant anisotropies. We then perform spatially resolved spectral analysis by identifying five different regions characterized by high/low values of the Fe K EW. We find that the spatial distribution of the Fe K emission is correlated with that of Cr xxii. We also detect the Ti K line complex in the spectra extracted from the two regions with the highest values of Fe and Cr EWs. The Ti line emission remains undetected in regions where Fe and Cr EWs are low. Our results indicate that the post-shock Ti is spatially colocated with other iron-peak nuclei in Tycho’s SNR, in agreement with the predictions of multi-D models of SNe Ia.

  13. Yet another plasma diagnostic with He-like triplet: Probing energetic electrons behind SNR shocks with ASTRO-H SXS

    NASA Astrophysics Data System (ADS)

    Sawada, Makoto; Kaastra, Jelle

    We present a new X-ray line diagnostic to probe energetic electrons behind SNR shocks. SNR shocks are believed to be acceleration sites of the Galactic cosmic rays up to knee energy. In the early stage of acceleration, particles must have sufficient energies to cross the shock to enter diffusive shock acceleration. This requires supra-thermal energies for electrons, however, we currently do not know how electrons depart from the thermal pool to attain such energies. Hence observational constraints on the amount and energy distribution of supra-thermal electrons are awaited. Here we propose a new X-ray line diagnostic using the He-like triplet to detect and characterise the energy distribution of supra-thermal electrons. We simulate X-ray spectra of SNR plasma interacting with energetic electrons and find that the forbidden line of the He-like triplet is enhanced via inner-shell ionisation process of Li-like ions. Such an effect can be precisely measured by high-resolution spectroscopy with the coming ASTRO-H SXS instrument.

  14. Real-time Signal-to-noise Ratio (SNR) Estimation for BPSK and QPSK Modulation Using the Active Communications Channel

    NASA Technical Reports Server (NTRS)

    Manning, Robert M. (Inventor)

    2007-01-01

    Method and apparatus for estimating signal-to-noise ratio (SNR) gamma of a composite input signal e(t) on a phase modulated (e.g., BPSK) communications link. A first demodulator receives the composite input signal and a stable carrier signal and outputs an in-phase output signal; a second demodulator receives the composite input signal and a phase-shifted version of the carrier signal and outputs a quadrature-phase output signal; and phase error theta(sub E)(t) contained within the composite input signal e(t) is calculated from the outputs of the first and second demodulators. A time series of statistically independent phase error measurements theta(sub E)(t(sub 1)), theta (sub E)(t(sub 2)),..., theta (sub E)(t(sub k)) is obtained from the composite input signal subtending a time interval delta t = t(sub k) - t(sub 1) whose value is small enough such that gamma(t) and sigma(t) can be taken to be constant in delta t. A biased estimate gamma(sup *) for the signal-to-noise ratio (SNR) gamma if the composite input signal is calculated using maximum likelihood (ML) estimation techniques, and an unbiased estimate gamma(sup ^) for the signal-to-noise ratio (SNR) gamma of the composite input signal is determined from the biased estimate gamma(sup *), such as by use of a look-up table.

  15. U17/snR30 is a ubiquitous snoRNA with two conserved sequence motifs essential for 18S rRNA production.

    PubMed

    Atzorn, Vera; Fragapane, Paola; Kiss, Tamás

    2004-02-01

    Saccharomyces cerevisiae snR30 is an essential box H/ACA small nucleolar RNA (snoRNA) required for the processing of 18S rRNA. Here, we show that the previously characterized human, reptilian, amphibian, and fish U17 snoRNAs represent the vertebrate homologues of yeast snR30. We also demonstrate that U17/snR30 is present in the fission yeast Schizosaccharomyces pombe and the unicellular ciliated protozoan Tetrahymena thermophila. Evolutionary comparison revealed that the 3'-terminal hairpins of U17/snR30 snoRNAs contain two highly conserved sequence motifs, the m1 (AUAUUCCUA) and m2 (AAACCAU) elements. Mutation analysis of yeast snR30 demonstrated that the m1 and m2 elements are essential for early cleavages of the 35S pre-rRNA and, consequently, for the production of mature 18S rRNA. The m1 and m2 motifs occupy the opposite strands of an internal loop structure, and they are located invariantly 7 nucleotides upstream from the ACA box of U17/snR30 snoRNAs. U17/snR30 is the first identified box H/ACA snoRNA that possesses an evolutionarily conserved role in the nucleolytic processing of eukaryotic pre-rRNA.

  16. EPIC Study of Two Enigmatic Sources: The Mouse and SNR 359.1-0.5

    NASA Technical Reports Server (NTRS)

    Pavlov, George

    2004-01-01

    The objective of the original proposal was to observe the Mouse pulsar wind nebula (associated with PSR J1744-2958) and the nearby supernova remnant G359.1-0.5, where the pulsar was probably born, with the XMM-Newton observatory to study the properties of these objects. SNR G359.1-0.5 was accepted as a Category C target and has not been observed. The Mouse was observed on April 27,2003 for 52 ks. The image analysis has shown that the Mouse is extended in the East-West direction, possibly along the direction of the pulsar's proper motion. The spectrum of this pulsar wind nebula can be described as an absorbed power law with the photon index GAMMA = 1.9 plus or minus 0.1, effective hydrogen column density n(sub H) = (2.6 plus or minus 0.1) x 10(exp 22) per square centimeter, and flux F = 1.8 x 10(exp -11) erg per square centimeter per second in the 1-10 keV energy range. Based on the n(sub H) value, the distance to the source is about 5 kpc, which results in the luminosity 3.7 x 10(exp 34) erg per second. We conclude that PSR J1744-2958 and the Mouse are not physically associated with G359.1-0.5, which lies at a larger distance. In addition to the Mouse, we also detected two Low-Mass X-ray Binaries, SLX 1744-299 and 1744-300, in the EPIC MOS and PN fields of view. The latter of these objects showed a Type I X-ray burst during our observation, with a rise time of 5 s and decay time of 60 s. A very strong pileup during the burst made the analysis of the burst properties unreliable. The spectral analysis of the persistent radiation from SLX 1744-299 and 1744-300 yields the hydrogen column densities of 3.2 plus or minus 0.1 and (3.6 plus or minus 0.2) x 10(exp 22) per square centimeter, respectively, which suggests that the sources are close to the Galactic center (d = 8-9 kpc). The spectra can be reasonably well fitted with a blackbody plus thin disk model, with the blackbody temperatures of 1.7 plus or minus 0.2 and 1.8 plus or minus 0.2 keV, respectively.

  17. Ein statistisches Modell zum Einfluß der thermischen Bewegung auf NMR-Festkörperspektren

    NASA Astrophysics Data System (ADS)

    Ploss, W.; Freude, D.; Pfeifer, H.; Schmiedel, H.

    Es wird ein statistisches Modell zum Einfluß der thermischen Bewegung auf die NMR-Linienform vorgestellt, das die Verschmälerung von Festkörper-Spektren bei wachsender Temperatur beschreibt. Das Modell geht von der Annahme aus, daß nach einer Ortsveränderung eines Kerns infolge thermischer Bewegung jede beliebige Kernresonanzfrequenz mit der durch das Festkörperspektrum vorgegebenen Wahrscheinlichkeit angenommen werden kann. Am Beispiel der Festkörper-Gaußlinie wird der Unterschied zu dem bekannten Modell von ANDERSON und WEISS verdeutlicht.Translated AbstractA Statistical Model for the Influence of Thermal Motion on N. M. R. Spectra in SolidsA theory is proposed which allows to describe the narrowing of n. m. r.-line width in the presence of thermal motions of the spins. The model is based on the assumption, that the local resonance frequency of a given spin immediately after the jump is distributed according to the n. m. r.-line shape of the rigid lattice. The difference to the well-known ANDERSON-WEISS-model of spectral narrowing is demonstrated for a gaussian line shape.

  18. Combining parallel detection of proton echo planar spectroscopic imaging (PEPSI) measurements with a data-consistency constraint improves SNR.

    PubMed

    Tsai, Shang-Yueh; Hsu, Yi-Cheng; Chu, Ying-Hua; Kuo, Wen-Jui; Lin, Fa-Hsuan

    2015-12-01

    One major challenge of MRSI is the poor signal-to-noise ratio (SNR), which can be improved by using a surface coil array. Here we propose to exploit the spatial sensitivity of different channels of a coil array to enforce the k-space data consistency (DC) in order to suppress noise and consequently to improve MRSI SNR. MRSI data were collected using a proton echo planar spectroscopic imaging (PEPSI) sequence at 3 T using a 32-channel coil array and were averaged with one, two and eight measurements (avg-1, avg-2 and avg-8). The DC constraint was applied using a regularization parameter λ of 1, 2, 3, 5 or 10. Metabolite concentrations were quantified using LCModel. Our results show that the suppression of noise by applying the DC constraint to PEPSI reconstruction yields up to 32% and 27% SNR gain for avg-1 and avg-2 data with λ = 5, respectively. According to the reported Cramer-Rao lower bounds, the improvement in metabolic fitting was significant (p < 0.01) when the DC constraint was applied with λ ≥ 2. Using the DC constraint with λ = 3 or 5 can minimize both root-mean-square errors and spatial variation for all subjects using the avg-8 data set as reference values. Our results suggest that MRSI reconstructed with a DC constraint can save around 70% of scanning time to obtain images and spectra with similar SNRs using λ = 5.

  19. THE PROGENITOR OF THE TYPE Ia SUPERNOVA THAT CREATED SNR 0519-69.0 IN THE LARGE MAGELLANIC CLOUD

    SciTech Connect

    Edwards, Zachary I.; Pagnotta, Ashley; Schaefer, Bradley E.

    2012-03-10

    Models for the progenitor systems of Type Ia supernovae can be divided into double-degenerate systems, which contain two white dwarfs, and single-degenerate systems, which contain one white dwarf plus one companion star (either a red giant, a subgiant, or a >1.16 M{sub Sun} main-sequence star). The white dwarf is destroyed in the supernova explosion, but any non-degenerate companion remains intact. We present the results of a search for an ex-companion star in SNR 0519-69.0, located in the Large Magellanic Cloud, based on images taken with the Hubble Space Telescope with a limiting magnitude of V = 26.05. SNR 0519-69.0 is confidently known to be from a Type Ia supernova based on its light echoes and X-ray spectra. The geometric center of the remnant (based on the H{alpha} and X-ray shell) is at 05:19:34.83, -69:02:06.92 (J2000). Accounting for the measurement uncertainties, the orbital velocity, and the kick velocity, any ex-companion star must be within 4.''7 of this position at the 99.73% confidence level. This circle contains 27 main-sequence stars brighter than V = 22.7, any one of which could be the ex-companion star left over from a supersoft source progenitor system. The circle contains no post-main-sequence stars, and this rules out the possibility of all other published single-degenerate progenitor classes (including symbiotic stars, recurrent novae, helium donors, and the spin-up/spin-down models) for this particular supernova. The only remaining possibility is that SNR 0519-69.0 was formed from either a supersoft source or a double-degenerate progenitor system.

  20. Timing considerations for preclinical MRgRT: effects of ion diffusion, SNR and imaging times on FXG gel calibration

    NASA Astrophysics Data System (ADS)

    Welch, M.; Foltz, W. D.; Jaffray, D. A.

    2015-01-01

    Sub-millimeter resolution images are required for gel dosimeters to be used in preclinical research, which is challenging for MR probed ferrous xylenol-orange (FXG) dosimeters due to ion diffusion and inadequate SNR. A preclinical 7 T MR, small animal irradiator and FXG dosimeters were used in all experiments. Ion diffusion was analyzed using high resolution (0.2 mm/pixel) T1 MR images collected every 5 minutes, post-irradiation, for an hour. Using Fick's second law, ion diffusion was approximated for the first hour post-irradiation. SNR, T1 map precision and calibration fit were determined for two MR protocols: (1) 10 minute acquisition, 0.35mm/pixel and 3mm slices, (2) 45 minute acquisition, 0. 25 mm/pixel and 2 mm slices. SNR and T1 map precision were calculated using a Monte Carlo simulation. Calibration curves were determined by plotting R1 relaxation rates versus depth dose data, and fitting a linear trend line. Ion diffusion was estimated as 0.003mm2 in the first hour post-irradiation. For protocols (1) and (2) respectively, Monte Carlo simulation predicted T1 precisions of 3% and 5% within individual voxels using experimental SNRs; the corresponding measured T1 precisions were 8% and 12%. The linear trend lines reported slopes of 27 ± 3 Gy*s (R2: 0.80 ± 0.04) and 27 ± 4 Gy*s (R2: 0.90 ± 0.04). Ion diffusion is negligible within the first hour post-irradiation, and an accurate and reproducible calibration can be achieved in a preclinical setting with sub-millimeter resolution.

  1. Combining parallel detection of proton echo planar spectroscopic imaging (PEPSI) measurements with a data-consistency constraint improves SNR.

    PubMed

    Tsai, Shang-Yueh; Hsu, Yi-Cheng; Chu, Ying-Hua; Kuo, Wen-Jui; Lin, Fa-Hsuan

    2015-12-01

    One major challenge of MRSI is the poor signal-to-noise ratio (SNR), which can be improved by using a surface coil array. Here we propose to exploit the spatial sensitivity of different channels of a coil array to enforce the k-space data consistency (DC) in order to suppress noise and consequently to improve MRSI SNR. MRSI data were collected using a proton echo planar spectroscopic imaging (PEPSI) sequence at 3 T using a 32-channel coil array and were averaged with one, two and eight measurements (avg-1, avg-2 and avg-8). The DC constraint was applied using a regularization parameter λ of 1, 2, 3, 5 or 10. Metabolite concentrations were quantified using LCModel. Our results show that the suppression of noise by applying the DC constraint to PEPSI reconstruction yields up to 32% and 27% SNR gain for avg-1 and avg-2 data with λ = 5, respectively. According to the reported Cramer-Rao lower bounds, the improvement in metabolic fitting was significant (p < 0.01) when the DC constraint was applied with λ ≥ 2. Using the DC constraint with λ = 3 or 5 can minimize both root-mean-square errors and spatial variation for all subjects using the avg-8 data set as reference values. Our results suggest that MRSI reconstructed with a DC constraint can save around 70% of scanning time to obtain images and spectra with similar SNRs using λ = 5. PMID:26484749

  2. Young Remnants of Type Ia Supernovae and Their Progenitors: A Study of SNR G1.9+0.3

    NASA Astrophysics Data System (ADS)

    Chakraborti, Sayan; Childs, Francesca; Soderberg, Alicia

    2016-03-01

    SNe Ia, with their remarkably homogeneous light curves and spectra, have been used as standardizable candles to measure the accelerating expansion of the universe. Yet, their progenitors remain elusive. Common explanations invoke a degenerate star (white dwarf) that explodes upon almost reaching the Chandrasekhar limit, by either steadily accreting mass from a companion star or violently merging with another degenerate star. We show that circumstellar interaction in young Galactic supernova remnants can be used to distinguish between these single and double degenerate (DD) progenitor scenarios. Here we propose a new diagnostic, the surface brightness index, which can be computed from theory and compared with Chandra and Very Large Array (VLA) observations. We use this method to demonstrate that a DD progenitor can explain the decades-long flux rise and size increase of the youngest known galactic supernova remnant (SNR), G1.9+0.3. We disfavor a single degenerate scenario for SNR G1.9+0.3. We attribute the observed properties to the interaction between a steep ejecta profile and a constant density environment. We suggest using the upgraded VLA, ASKAP, and MeerKAT to detect circumstellar interaction in the remnants of historical SNe Ia in the Local Group of galaxies. This may settle the long-standing debate over their progenitors.

  3. DISCOVERY OF VERY HIGH ENERGY {gamma}-RAY EMISSION FROM THE SNR G54.1+0.3

    SciTech Connect

    Acciari, V. A.; Benbow, W.; Aliu, E.; Boltuch, D.; Arlen, T.; Aune, T.; Bautista, M.; Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R.; Bradbury, S. M.; Butt, Y.; Byrum, K.; Cesarini, A.; Ciupik, L.; Cui, W.; Finley, J. P.; Duke, C.; Finnegan, G. E-mail: wakely@uchicago.ed

    2010-08-10

    We report the discovery of very high energy (VHE) gamma-ray emission from the direction of the SNR G54.1+0.3 using the VERITAS ground-based gamma-ray observatory. The TeV signal has an overall significance of 6.8{sigma} and appears pointlike given the resolution of the instrument. The integral flux above 1 TeV is 2.5% of the Crab Nebula flux and significant emission is measured between 250 GeV and 4 TeV, well described by a power-law energy spectrum dN/dE {approx} E {sup -{Gamma}} with a photon index {Gamma} = 2.39 {+-} 0.23{sub stat} {+-} 0.30{sub sys}. We find no evidence of time variability among observations spanning almost two years. Based on the location, the morphology, the measured spectrum, the lack of variability, and a comparison with similar systems previously detected in the TeV band, the most likely counterpart of this new VHE gamma-ray source is the pulsar wind nebula (PWN) in the SNR G54.1+0.3. The measured X-ray to VHE gamma-ray luminosity ratio is the lowest among all the nebulae supposedly driven by young rotation-powered pulsars, which could indicate a particle-dominated PWN.

  4. Late-Time Evolution of Composite Supernova Remnants: Deep Chandra Observations and Hydrodynamical Modeling of a Crushed Pulsar Wind Nebula in SNR G327.1-1.1

    NASA Technical Reports Server (NTRS)

    Temim, Tea; Slane, Patrick; Kolb, Christopher; Blondin, John; Hughes, John P.; Bucciantini, Niccolo

    2015-01-01

    In an effort to better understand the evolution of composite supernova remnants (SNRs) and the eventual fate of relativistic particles injected by their pulsars, we present a multifaceted investigation of the interaction between a pulsar wind nebula (PWN) and its host SNR G327.1-1.1. Our 350 ks Chandra X-ray observations of SNR G327.1-1.1 reveal a highly complex morphology; a cometary structure resembling a bow shock, prong-like features extending into large arcs in the SNR interior, and thermal emission from the SNR shell. Spectral analysis of the non-thermal emission offers clues about the origin of the PWN structures, while enhanced abundances in the PWN region provide evidence for mixing of supernova ejecta with PWN material. The overall morphology and spectral properties of the SNR suggest that the PWN has undergone an asymmetric interaction with the SNR reverse shock(RS) that can occur as a result of a density gradient in the ambient medium and or a moving pulsar that displaces the PWN from the center of the remnant. We present hydrodynamical simulations of G327.1-1.1 that show that its morphology and evolution can be described by a approx. 17,000 yr old composite SNR that expanded into a density gradient with an orientation perpendicular to the pulsar's motion. We also show that the RSPWN interaction scenario can reproduce the broadband spectrum of the PWN from radio to gamma-ray wavelengths. The analysis and modeling presented in this work have important implications for our general understanding of the structure and evolution of composite SNRs.

  5. Discovery of TeV Gamma-Ray Emission toward Supernova Remnant SNR G78.2+2.1

    NASA Astrophysics Data System (ADS)

    Aliu, E.; Archambault, S.; Arlen, T.; Aune, T.; Beilicke, M.; Benbow, W.; Bird, R.; Bouvier, A.; Bradbury, S. M.; Buckley, J. H.; Bugaev, V.; Byrum, K.; Cannon, A.; Cesarini, A.; Ciupik, L.; Collins-Hughes, E.; Connolly, M. P.; Cui, W.; Dickherber, R.; Duke, C.; Dumm, J.; Dwarkadas, V. V.; Errando, M.; Falcone, A.; Federici, S.; Feng, Q.; Finley, J. P.; Finnegan, G.; Fortson, L.; Furniss, A.; Galante, N.; Gall, D.; Gillanders, G. H.; Godambe, S.; Gotthelf, E. V.; Griffin, S.; Grube, J.; Gyuk, G.; Hanna, D.; Holder, J.; Huan, H.; Hughes, G.; Humensky, T. B.; Kaaret, P.; Karlsson, N.; Kertzman, M.; Khassen, Y.; Kieda, D.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; Lee, K.; Madhavan, A. S.; Maier, G.; Majumdar, P.; McArthur, S.; McCann, A.; Millis, J.; Moriarty, P.; Mukherjee, R.; Nelson, T.; O'Faoláin de Bhróithe, A.; Ong, R. A.; Orr, M.; Otte, A. N.; Pandel, D.; Park, N.; Perkins, J. S.; Pohl, M.; Popkow, A.; Prokoph, H.; Quinn, J.; Ragan, K.; Reyes, L. C.; Reynolds, P. T.; Roache, E.; Rose, H. J.; Ruppel, J.; Saxon, D. B.; Schroedter, M.; Sembroski, G. H.; Şentürk, G. D.; Skole, C.; Telezhinsky, I.; Tešić, G.; Theiling, M.; Thibadeau, S.; Tsurusaki, K.; Tyler, J.; Varlotta, A.; Vassiliev, V. V.; Vincent, S.; Wakely, S. P.; Ward, J. E.; Weekes, T. C.; Weinstein, A.; Weisgarber, T.; Welsing, R.; Williams, D. A.; Zitzer, B.

    2013-06-01

    We report the discovery of an unidentified, extended source of very-high-energy gamma-ray emission, VER J2019+407, within the radio shell of the supernova remnant SNR G78.2+2.1, using 21.4 hr of data taken by the VERITAS gamma-ray observatory in 2009. These data confirm the preliminary indications of gamma-ray emission previously seen in a two-year (2007-2009) blind survey of the Cygnus region by VERITAS. VER J2019+407, which is detected at a post-trials significance of 7.5 standard deviations in the 2009 data, is localized to the northwestern rim of the remnant in a region of enhanced radio and X-ray emission. It has an intrinsic extent of 0{.\\!\\!^\\circ }23 +/- {0{.\\!\\!^\\circ }03_stat} {}^{+0{.\\!\\!^\\circ }04}_{-0{.\\!\\!^\\circ }02sys} and its spectrum is well-characterized by a differential power law (dN/dE = N 0 × (E/TeV)-Γ) with a photon index of Γ = 2.37 ± 0.14stat ± 0.20sys and a flux normalization of N 0 = 1.5 ± 0.2stat ± 0.4sys × 10-12 photon TeV-1 cm-2 s-1. This yields an integral flux of 5.2 ± 0.8stat ± 1.4sys × 10-12 photon cm-2 s-1 above 320 GeV, corresponding to 3.7% of the Crab Nebula flux. We consider the relationship of the TeV gamma-ray emission with the GeV gamma-ray emission seen from SNR G78.2+2.1 as well as that seen from a nearby cocoon of freshly accelerated cosmic rays. Multiple scenarios are considered as possible origins for the TeV gamma-ray emission, including hadronic particle acceleration at the SNR shock.

  6. Detailed study of SNR G306.3-0.9 using XMM-Newton and Chandra observations

    NASA Astrophysics Data System (ADS)

    Combi, J. A.; García, F.; Suárez, A. E.; Luque-Escamilla, P. L.; Paron, S.; Miceli, M.

    2016-08-01

    Aims: We aim to study the spatial distribution of the physical and chemical properties of the X-ray emitting plasma of the supernova remnant (SNR) G306.3-0.9 in detail to obtain constraints on its ionization stage, the progenitor supernova explosion, and the age of the remnant. Methods: We used combined data from XMM-Newton and Chandra observatories to study the X-ray morphology of G306.3-0.9 in detail. A spatially resolved spectral analysis was used to obtain physical and geometrical parameters of different regions of the remnant. Spitzer infrared observations, available in the archive, were also used to constrain the progenitor supernova and study the environment in which the remnant evolved. Results: The X-ray morphology of the remnant displays a non-uniform structure of semi-circular appearance, with a bright southwest region and very weak or almost negligible X-ray emission in its northern part. These results indicate that the remnant is propagating in a non-uniform environment as the shock fronts are encountering a high-density medium, where enhanced infrared emission is detected. The X-ray spectral analysis of the selected regions shows distinct emission-line features of several metal elements, confirming the thermal origin of the emission. The X-ray spectra are well represented by a combination of two absorbed thermal plasma models: one in equilibrium ionization (VAPEC) with a mean temperature of ~0.19 keV, and another out of equilibrium ionization (VNEI) at a higher temperature of ~1.1 or 1.6-1.9 keV. For regions located in the northeast, central, and southwest part of the SNR, we found elevated abundances of Si, S, Ar, Ca, and Fe, typical of ejecta material. The outer regions located northwest and south show values of the abundances above solar but lower than to those found in the central regions. This suggests that the composition of the emitting outer parts of the SNR is a combination of ejecta and shocked material of the interstellar medium. The

  7. DISCOVERY OF TeV GAMMA-RAY EMISSION TOWARD SUPERNOVA REMNANT SNR G78.2+2.1

    SciTech Connect

    Aliu, E.; Archambault, S.; Arlen, T.; Aune, T.; Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R.; Benbow, W.; Bird, R.; Cannon, A.; Collins-Hughes, E.; Bouvier, A.; Bradbury, S. M.; Byrum, K.; Cesarini, A.; Connolly, M. P.; Ciupik, L.; Cui, W.; Duke, C.; and others

    2013-06-20

    We report the discovery of an unidentified, extended source of very-high-energy gamma-ray emission, VER J2019+407, within the radio shell of the supernova remnant SNR G78.2+2.1, using 21.4 hr of data taken by the VERITAS gamma-ray observatory in 2009. These data confirm the preliminary indications of gamma-ray emission previously seen in a two-year (2007-2009) blind survey of the Cygnus region by VERITAS. VER J2019+407, which is detected at a post-trials significance of 7.5 standard deviations in the 2009 data, is localized to the northwestern rim of the remnant in a region of enhanced radio and X-ray emission. It has an intrinsic extent of 0.23 Degree-Sign .23 {+-} 0. Degree-Sign 03{sub stat-0 Degree-Sign .02sys}{sup +0 Degree-Sign .04} and its spectrum is well-characterized by a differential power law (dN/dE = N{sub 0} Multiplication-Sign (E/TeV){sup -{Gamma}}) with a photon index of {Gamma} = 2.37 {+-} 0.14{sub stat} {+-} 0.20{sub sys} and a flux normalization of N{sub 0} = 1.5 {+-} 0.2{sub stat} {+-} 0.4{sub sys} Multiplication-Sign 10{sup -12} photon TeV{sup -1} cm{sup -2} s{sup -1}. This yields an integral flux of 5.2 {+-} 0.8{sub stat} {+-} 1.4{sub sys} Multiplication-Sign 10{sup -12} photon cm{sup -2} s{sup -1} above 320 GeV, corresponding to 3.7% of the Crab Nebula flux. We consider the relationship of the TeV gamma-ray emission with the GeV gamma-ray emission seen from SNR G78.2+2.1 as well as that seen from a nearby cocoon of freshly accelerated cosmic rays. Multiple scenarios are considered as possible origins for the TeV gamma-ray emission, including hadronic particle acceleration at the SNR shock.

  8. Detailed 21 cm observations towards the TeV γ-ray SNR HESS J1731-347

    NASA Astrophysics Data System (ADS)

    Fukuda, Tatsuya; Yamamoto, Hiroaki; Fukui, Yasuo; Torii, Kazufumi; Hayakawa, Takahiro; Okuda, Takeshi; Sano, Hidetoshi; Yoshiike, Satoshi

    2012-10-01

    HESS J1731-347 is one of the unique SNRs which show the TeV gamma-ray shell like morphology. Our new study succeeded to reveal the distributions of the ISM proton that coincide well with the TeV gamma-ray distributions and discussed that both the hadronic and leptonic processes are possibly working in this region. However, the present ISM resolutions of a few arcmin of the given data sets are not sufficient to understand the detailed ISM distributions and the origin of the gamma-ray emission. We will use the ATCA to image 21cm radio continuum emission and HI emission in the region to a resolution of ~30" and study the interaction between the shock wave and the ISM in detail. Such results are a crucial component in testing for the origin of SNR gamma-rays.

  9. The x ray population in globular clusters and three crab-like SNR in the large Magellanic cloud

    NASA Technical Reports Server (NTRS)

    Helfand, David J.

    1993-01-01

    This document is to serve as the requisite Final Technical Report on grant NAG5-1557 which was awarded under the NASA ROSAT Guest Investigator Program to Columbia University. In response to the NASA Research Anouncement describing the first round of Guest Investigations to be carried out under the U.S.-German ROSAT Program (AO-1), the PI submitted several proposals, three of which were accepted in part: (1) the x-ray population of globular clusters; (2) three crab-like SNR in the Large Magellanic Cloud; and (3) x rays from nearby radio pulsars. The status of these three programs as of 31 May 1993, the termination date of the grant, is reported.

  10. Detailed investigation of the gamma-ray emission in the vicinity of SNR W28 with Fermi-LAT

    SciTech Connect

    Hanabata, Y.; Katagiri, H.; Hewitt, J.W.; Ballet, J.; Fukui, Y.; Hayakawa, T.; Lemoine-Goumard, M.; Strong, A. W.; Yamazaki, R. E-mail: katagiri@mx.ibaraki.ac.jp

    2014-05-10

    We present a detailed investigation of the γ-ray emission in the vicinity of the supernova remnant (SNR) W28 (G6.4–0.1) observed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. We detected significant γ-ray emission spatially coincident with TeV sources HESS J1800–240A, B, and C, located outside the radio boundary of the SNR. Their spectra in the 2-100 GeV band are consistent with the extrapolation of the power-law spectra of the TeV sources. We also identified a new source of GeV emission, dubbed Source W, which lies outside the boundary of TeV sources and coincides with radio emission from the western part of W28. All of the GeV γ-ray sources overlap with molecular clouds in the velocity range from 0 to 20 km s{sup –1}. Under the assumption that the γ-ray emission toward HESS J1800–240A, B, and C comes from π{sup 0} decay due to the interaction between the molecular clouds and cosmic rays (CRs) escaping from W28, they can be naturally explained by a single model in which the CR diffusion coefficient is smaller than the theoretical expectation in the interstellar space. The total energy of the CRs escaping from W28 is constrained through the same modeling to be larger than ∼2 × 10{sup 49} erg. The emission from Source W can also be explained with the same CR escape scenario.

  11. Detailed Investigation of the Gamma-Ray Emission in the Vicinity of SNR W28 with FERMI-LAT

    NASA Technical Reports Server (NTRS)

    Hanabata, Y.; Katagiri, H.; Hewitt, John William; Ballet, J.; Fukazawa, Y.; Fukui, Y.; Hayakawa, T.; Lemoine-Goumard, M.; Pedaletti, G.; Strong, A. W.; Torres, D. F.; Yamazaki, R.

    2014-01-01

    We present a detailed investigation of the Gamma-ray emission in the vicinity of the supernova remnant (SNR) W28 (G6.4-0.1) observed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. We detected significant ? -ray emission spatially coincident with TeV sources HESS J1800-240A, B, and C, located outside the radio boundary of the SNR. Their spectra in the 2-100 GeV band are consistent with the extrapolation of the power-law spectra of the TeV sources. We also identified a new source of GeV emission, dubbed Source W, which lies outside the boundary of TeV sources and coincides with radio emission from the western part of W28. All of the GeV Gamma-ray sources overlap with molecular clouds in the velocity range from 0 to 20 km s (exp-1). Under the assumption that the Gamma-ray emission toward HESS J1800-240A, B, and C comes from 3.14(exp0) decay due to the interaction between the molecular clouds and cosmic rays (CRs) escaping from W28, they can be naturally explained by a single model in which the CR diffusion coefficient is smaller than the theoretical expectation in the interstellar space. The total energy of the CRs escaping from W28 is constrained through the same modeling to be larger than is approximately 2 × 10(exp49) erg. The emission from Source W can also be explained with the same CR escape scenario.

  12. Detailed Investigation of the Gamma-Ray Emission in the Vicinity of SNR W28 with FERMI-LAT

    NASA Astrophysics Data System (ADS)

    Hanabata, Y.; Katagiri, H.; Hewitt, J. W.; Ballet, J.; Fukazawa, Y.; Fukui, Y.; Hayakawa, T.; Lemoine-Goumard, M.; Pedaletti, G.; Strong, A. W.; Torres, D. F.; Yamazaki, R.

    2014-05-01

    We present a detailed investigation of the γ-ray emission in the vicinity of the supernova remnant (SNR) W28 (G6.4-0.1) observed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. We detected significant γ-ray emission spatially coincident with TeV sources HESS J1800-240A, B, and C, located outside the radio boundary of the SNR. Their spectra in the 2-100 GeV band are consistent with the extrapolation of the power-law spectra of the TeV sources. We also identified a new source of GeV emission, dubbed Source W, which lies outside the boundary of TeV sources and coincides with radio emission from the western part of W28. All of the GeV γ-ray sources overlap with molecular clouds in the velocity range from 0 to 20 km s-1. Under the assumption that the γ-ray emission toward HESS J1800-240A, B, and C comes from π0 decay due to the interaction between the molecular clouds and cosmic rays (CRs) escaping from W28, they can be naturally explained by a single model in which the CR diffusion coefficient is smaller than the theoretical expectation in the interstellar space. The total energy of the CRs escaping from W28 is constrained through the same modeling to be larger than ~2 × 1049 erg. The emission from Source W can also be explained with the same CR escape scenario.

  13. OT2_pghavami_1: Herschel imaging of SNR G292.0+1.8: Cas A's older cousin?

    NASA Astrophysics Data System (ADS)

    Ghavamian, P.

    2011-09-01

    It is well-known that supernovae play a key role in creating and distributing elements throughout the universe, but less well-known is their contribution to the overall budget of dust in the ISM. Theoretical models suggest that core-collapse supernovae should produce large quantities of dust, but observational evidence for this is still debated. Even if significant quantities of dust are produced, does it survive the passage of the reverse shock to enter the ISM? Does the forward shock destroy all dust that it encounters? Near and mid-IR observations with Spitzer and AKARI have begun to answer these questions, but the long wavelength cameras of Herschel are necessary for a complete picture. We propose detailed observations of G292.0+1.8, a large Galactic supernova remnant (SNR) that has been called the "older cousin" of Cassiopeia A. One of the few known oxygen-rich remnants, G292 is a 3000 year old textbook example of a core-collapse SNR expanding into its own circumstellar medium (CSM), the wind of a red giant. It is one of the most well-studied SNRs at all wavelengths, from radio to X-rays. At 8' in diameter, it is large enough for the emission from the forward-shock CSM to be well-separated from that of the reverse-shocked ejecta, yet it is still small enough to be fully covered by Herschel in a reasonably small amount of time. We will obtain PACS and SPIRE imaging of the entire remnant. PACS observations will be sensitive to forward-shocked material, while SPIRE data will tell us whether large amounts of ejecta dust are present in the remnant. We will use the far-IR data in conjunction with X-ray and optical data to obtain a complete picture of the dynamical evolution of the remnant, and advance our understanding of the nature of dust in the universe.

  14. X-RAY EMISSION FROM HESS J1731-347/SNR G353.6-0.7 AND CENTRAL COMPACT SOURCE XMMS J173203-344518

    SciTech Connect

    Tian, W. W.; Li, Z.; Leahy, D. A.; Yang, J.; Lu, D.; Yang, X. J.; Yamazaki, R. E-mail: wtian@ucalgary.c

    2010-04-01

    We present new results of the HESS J1731-347/SNR G353.6-0.7 system from XMM-Newton and Suzaku X-ray observations and Delinha CO observations. We discover extended hard X-rays coincident with the bright, extended TeV source HESS J1731-347 and the shell of the radio supernova remnant (SNR). We find that spatially resolved X-ray spectra can generally be characterized by an absorbed power-law model, with a photon index of {approx}2, typical of non-thermal emission. A bright X-ray compact source, XMMS J173203-344518, is also detected near the center of the SNR. We find no evidence of a radio counterpart or an extended X-ray morphology for this source, making it unlikely to be a pulsar wind nebular (PWN). The spectrum of the source can be well fitted by an absorbed blackbody with a temperature of {approx}0.5 keV plus a power-law tail with a photon index of {approx}5, reminiscent of the X-ray emission of a magnetar. CO observations toward the inner part of the High Energy Stereoscopic System (HESS) source reveal a bright cloud component at -20 +- 4 km s{sup -1}, which is likely located at the same distance of {approx}3.2 kpc as the SNR. Based on the probable association between the X-ray and gamma-ray emissions and likely association between the CO cloud and the SNR, we argue that the extended TeV emission originates from the interaction between the SNR shock and the adjacent CO clouds rather than from a PWN.

  15. THE NEUTRAL INTERSTELLAR GAS TOWARD SNR W44: CANDIDATES FOR TARGET PROTONS IN HADRONIC {gamma}-RAY PRODUCTION IN A MIDDLE-AGED SUPERNOVA REMNANT

    SciTech Connect

    Yoshiike, S.; Fukuda, T.; Sano, H.; Ohama, A.; Moribe, N.; Torii, K.; Hayakawa, T.; Okuda, T.; Yamamoto, H.; Mizuno, N.; Onishi, T.; Fukui, Y.; Tajima, H.; Maezawa, H.; Mizuno, A.; Nishimura, A.; Kimura, K.; Ogawa, H.; Giuliani, A.; Koo, B.-C.

    2013-05-10

    We present an analysis of the interstellar medium (ISM) toward the {gamma}-ray supernova remnant (SNR) W44. We used NANTEN2 {sup 12}CO(J = 2-1) and {sup 12}CO(J = 1-0) data and Arecibo H I data in order to identify the molecular and atomic gas in the SNR. We confirmed that the molecular gas is located in the SNR shell with a primary peak toward the eastern edge of the shell. We newly identified high-excitation molecular gas along the eastern shell of the SNR in addition to the high-excitation broad gas previously observed inside the shell; the line intensity ratio between the {sup 12}CO(J = 2-1) and {sup 12}CO(J = 1-0) transitions in these regions is greater than {approx}1.0, suggesting a kinetic temperature of 30 K or higher, which is most likely due to heating by shock interaction. By comparing the ISM with {gamma}-rays, we find that target protons of hadronic origin are dominated by molecular protons of average density around 200 cm{sup -3}, where the possible contribution of atomic protons is 10% or less. This average density is consistent with the recent discovery of the low-energy {gamma}-rays suppressed in 50 MeV-10 GeV as observed with AGILE and Fermi. The {gamma}-ray spectrum differs from place to place in the SNR, suggesting that the cosmic-ray (CR) proton spectrum significantly changes within the middle-aged SNR perhaps due to the energy-dependent escape of CR protons from the acceleration site. We finally derive a total CR proton energy of {approx}10{sup 49} erg, consistent with the SN origin of the majority of the CRs in the Galaxy.

  16. X-Ray Emission from HESS J1731-347/SNR G353.6-0.7 and Central Compact Source XMMS J173203-344518

    NASA Astrophysics Data System (ADS)

    Tian, W. W.; Li, Z.; Leahy, D. A.; Yang, J.; Yang, X. J.; Yamazaki, R.; Lu, D.

    2010-04-01

    We present new results of the HESS J1731-347/SNR G353.6-0.7 system from XMM-Newton and Suzaku X-ray observations and Delinha CO observations. We discover extended hard X-rays coincident with the bright, extended TeV source HESS J1731-347 and the shell of the radio supernova remnant (SNR). We find that spatially resolved X-ray spectra can generally be characterized by an absorbed power-law model, with a photon index of ~2, typical of non-thermal emission. A bright X-ray compact source, XMMS J173203-344518, is also detected near the center of the SNR. We find no evidence of a radio counterpart or an extended X-ray morphology for this source, making it unlikely to be a pulsar wind nebular (PWN). The spectrum of the source can be well fitted by an absorbed blackbody with a temperature of ~0.5 keV plus a power-law tail with a photon index of ~5, reminiscent of the X-ray emission of a magnetar. CO observations toward the inner part of the High Energy Stereoscopic System (HESS) source reveal a bright cloud component at -20 ± 4 km s-1, which is likely located at the same distance of ~3.2 kpc as the SNR. Based on the probable association between the X-ray and γ-ray emissions and likely association between the CO cloud and the SNR, we argue that the extended TeV emission originates from the interaction between the SNR shock and the adjacent CO clouds rather than from a PWN.

  17. The Lighthouse nebula: a run-away pulsar, its PWN, jets and parent SNR

    NASA Astrophysics Data System (ADS)

    Pavan, L.; Bordas, P.; Puhlhofer, G.; et al.

    2016-06-01

    Some 10-20 kyr ago a pulsar was born from a core collapse event, receiving right away a strong kick. Nowadays this pulsar is powering the Lighthouse Nebula (IGR J11014-6103): a complex system of outflows comprising the bow-shock PWN, and two well collimated jets extending perpendicularly to the pulsar's direction of motion. Whereas sharing some clear commonalities with the well known Guitar Nebula, the Lighthouse nebula is the only such system where the parent supernova remnant is well visible and bright in X-rays. I will describe the results from our recent Chandra X-ray campaign, and follow-up optical and radio observations, analyse the properties of the PWN, and possible interpretations on the nature of the long helicoidal jets and of the other outflows that we identified. I will also discuss the link between this system and its parent supernova remnant MSH 11-61A, which could help shedding a light on the processes that give birth to such peculiar systems.

  18. Uranus' Persistent Patterns and Features from High-SNR Imaging in 2012-2014

    NASA Astrophysics Data System (ADS)

    Fry, Patrick M.; Sromovsky, Lawrence A.; de Pater, Imke; Hammel, Heidi B.; Marcus, Phillip

    2015-11-01

    Since 2012, Uranus has been the subject of an observing campaign utilizing high signal-to-noise imaging techniques at Keck Observatory (Fry et al. 2012, Astron. J. 143, 150-161). High quality observing conditions on four observing runs of consecutive nights allowed longitudinally-complete coverage of the atmosphere over a period of two years (Sromovsky et al. 2015, Icarus 258, 192-223). Global mosaic maps made from images acquired on successive nights in August 2012, November 2012, August 2013, and August 2014, show persistent patterns, and six easily distinguished long-lived cloud features, which we were able to track for long periods that ranged from 5 months to over two years. Two at similar latitudes are associated with dark spots, and move with the atmospheric zonal flow close to the location of their associated dark spot instead of following the flow at the latitude of the bright features. These features retained their morphologies and drift rates in spite of several close interactions. A second pair of features at similar latitudes also survived several close approaches. Several of the long-lived features also exhibited equatorward drifts and latitudinal oscillations. Also persistent are a remarkable near-equatorial wave feature and global zonal band structure. We will present imagery, maps, and analyses of these phenomena.PMF and LAS acknowledge support from NASA Planetary Astronomy Program; PMF and LAS acknowledge funding and technical support from W. M. Keck Observatory. We thank those of Hawaiian ancestry on whose sacred mountain we are privileged to be guests. Without their generous hospitality none of our groundbased observations would have been possible.

  19. Improvement of stress tolerance and leavening ability under multiple baking-associated stress conditions by overexpression of the SNR84 gene in baker's yeast.

    PubMed

    Lin, Xue; Zhang, Cui-Ying; Bai, Xiao-Wen; Feng, Bing; Xiao, Dong-Guang

    2015-03-16

    During the bread-making process, industrial baker's yeast cells are exposed to multiple baking-associated stresses, such as elevated high-temperature, high-sucrose and freeze-thaw stresses. There is a high demand for baker's yeast strains that could withstand these stresses with high leavening ability. The SNR84 gene encodes H/ACA snoRNA (small nucleolar RNA), which is known to be involved in pseudouridylation of the large subunit rRNA. However, the function of the SNR84 gene in baker's yeast coping with baking-associated stresses remains unclear. In this study, we explored the effect of SNR84 overexpression on baker's yeast which was exposed to high-temperature, high-sucrose and freeze-thaw stresses. These results suggest that overexpression of the SNR84 gene conferred tolerance of baker's yeast cells to high-temperature, high-sucrose and freeze-thaw stresses and enhanced their leavening ability in high-sucrose and freeze-thaw dough. These findings could provide a valuable insight for breeding of novel stress-resistant baker's yeast strains that are useful for baking.

  20. Improvement of stress tolerance and leavening ability under multiple baking-associated stress conditions by overexpression of the SNR84 gene in baker's yeast.

    PubMed

    Lin, Xue; Zhang, Cui-Ying; Bai, Xiao-Wen; Feng, Bing; Xiao, Dong-Guang

    2015-03-16

    During the bread-making process, industrial baker's yeast cells are exposed to multiple baking-associated stresses, such as elevated high-temperature, high-sucrose and freeze-thaw stresses. There is a high demand for baker's yeast strains that could withstand these stresses with high leavening ability. The SNR84 gene encodes H/ACA snoRNA (small nucleolar RNA), which is known to be involved in pseudouridylation of the large subunit rRNA. However, the function of the SNR84 gene in baker's yeast coping with baking-associated stresses remains unclear. In this study, we explored the effect of SNR84 overexpression on baker's yeast which was exposed to high-temperature, high-sucrose and freeze-thaw stresses. These results suggest that overexpression of the SNR84 gene conferred tolerance of baker's yeast cells to high-temperature, high-sucrose and freeze-thaw stresses and enhanced their leavening ability in high-sucrose and freeze-thaw dough. These findings could provide a valuable insight for breeding of novel stress-resistant baker's yeast strains that are useful for baking. PMID:25555226

  1. Multi-session complex averaging for high resolution high SNR 3T MR visualization of ex vivo hippocampus and insula

    NASA Astrophysics Data System (ADS)

    Stamm, Aymeric; Singh, Jolene M.; Scherrer, Benoit; Afacan, Onur; Warfield, Simon K.

    2015-03-01

    The hippocampus and the insula are responsible for episodic memory formation and retrieval. Hence, visualization of the cytoarchitecture of such structures is of primary importance to understand the underpinnings of conscious experience. Magnetic Resonance Imaging (MRI) offers an opportunity to non-invasively image these crucial structures. However, current clinical MR imaging operates at the millimeter scale while these anatomical landmarks are organized into sub-millimeter structures. For instance, the hippocampus contains several layers, including the CA3-dentate network responsible for encoding events and experiences. To investigate whether memory loss is a result of injury or degradation of CA3/dentate, spatial resolution must exceed one hundred micron, isotropic, voxel size. Going from one millimeter voxels to one hundred micron voxels results in a 1000× signal loss, making the measured signal close to or even way below the precision of the receiving coils. Consequently, the signal magnitude that forms the structural images will be biased and noisy, which results in inaccurate contrast and less than optimal signal-to-noise ratio (SNR). In this paper, we propose a strategy to perform high spatial resolution MR imaging of the hippocampus and insula with 3T scanners that enables accurate contrast (no systematic bias) and arbitrarily high SNR. This requires the collection of additional repeated measurements of the same image and a proper averaging of the k-space data in the complex domain. This comes at the cost of additional scan time, but long single-session scan times are not practical for obvious reasons. Hence, we also develop an approach to combine k-space data from multiple sessions, which enables the total scan time to be split into arbitrarily short sessions, where the patient is allowed to move and rest in-between. For validation, we hereby illustrate our multi-session complex averaging strategy by providing high spatial resolution 3T MR visualization

  2. Correlation of the genotoxic activation and kinetic properties of Salmonella enterica serovar Typhimurium nitroreductases SnrA and cnr with the redox potentials of nitroaromatic compounds and quinones.

    PubMed

    Salamanca-Pinzón, S G; Camacho-Carranza, R; Hernández-Ojeda, S L; Frontana-Uribe, B A; Espitia-Pinzón, C I; Espinosa-Aguirre, J J

    2010-05-01

    Bacterial nitroreductases (NRs) catalyse the oxygen-insensitive reduction of several nitro-substituted compounds and quinones. SnrA and cnr NRs have been previously identified in Salmonella enterica serovar Typhimurium; they reduce several environmental nitro compounds that display mutagenic activity in the Ames test. Although some of their biochemical properties have been reported, the substrate specificity of each protein over mutagenic nitro compounds is unknown; even more, the possible relationship between their capacity to activate nitro compounds into mutagens and the redox properties of putative substrates has been poorly investigated. We have purified SnrA and cnr and investigated their capacity to activate several mutagens in the Ames test as well as their kinetic parameters K(m) and V(max). Our results show that SnrA and cnr are able to activate 2,7-dinitrofluorene with the same efficiency and a similar mutagenic potency in the YG7132 tester strain; 1-nitropyrene and 1,3-dinitropyrene were efficiently activated by cnr, whereas 1,8-dinitropyrene, 1,6-dinitropyrene and 2-nitrofluorene were scarcely activated by either NR. The mutagenic potency of nitro compounds obtained in the presence of either enzyme correlates with their redox potential reported in the literature. On the other hand, a good correlation was obtained between the catalytic efficiency (V(max)/K(m)) of the purified cnr with the redox potential of eight molecules including nitro-substituted compounds and quinones. No correlation between redox potential and catalytic efficiency by SnrA was observed, suggesting that factors other than redox potential such as the structure of the compounds are involved in the catalytic efficiency of SnrA. PMID:20118186

  3. A CR-HYDRO-NEI MODEL OF MULTI-WAVELENGTH EMISSION FROM THE VELA JR. SUPERNOVA REMNANT (SNR RX J0852.0-4622)

    SciTech Connect

    Lee, Shiu-Hang; Nagataki, Shigehiro; Slane, Patrick O.; Patnaude, Daniel J.; Ellison, Donald C. E-mail: nagataki@yukawa.kyoto-u.ac.jp E-mail: dpatnaude@cfa.harvard.edu

    2013-04-10

    Based largely on energy budget considerations and the observed cosmic-ray (CR) ionic composition, supernova remnant (SNR) blast waves are the most likely sources of CR ions with energies at least up to the 'knee' near 10{sup 15} eV. Shocks in young shell-type TeV-bright SNRs are surely producing TeV particles, but the emission could be dominated by ions producing {pi}{sup 0}-decay emission or electrons producing inverse Compton gamma rays. Unambiguously identifying the GeV-TeV emission process in a particular SNR will not only help pin down the origin of CRs, it will also add significantly to our understanding of the diffusive shock acceleration (DSA) mechanism and improve our understanding of supernovae and the impact SNRs have on the circumstellar medium. In this study, we investigate the Vela Jr. SNR, an example of TeV-bright non-thermal SNRs. We perform hydrodynamic simulations coupled with nonlinear DSA and non-equilibrium ionization near the forward shock to confront currently available multi-wavelength data. We find, with an analysis similar to that used earlier for SNR RX J1713.7-3946, that self-consistently modeling the thermal X-ray line emission with the non-thermal continuum in our one-dimensional model strongly constrains the fitting parameters, and this leads convincingly to a leptonic origin for the GeV-TeV emission for Vela Jr. This conclusion is further supported by applying additional constraints from observation, including the radial brightness profiles of the SNR shell in TeV gamma rays, and the spatial variation of the X-ray synchrotron spectral index. We will discuss implications of our models on future observations by the next-generation telescopes.

  4. Infrared imaging and polarimetric observations of the pulsar wind nebula in SNR G21.5-0.9

    NASA Astrophysics Data System (ADS)

    Zajczyk, A.; Gallant, Y. A.; Slane, P.; Reynolds, S. P.; Bandiera, R.; Gouiffès, C.; Le Floc'h, E.; Comerón, F.; Koch Miramond, L.

    2012-06-01

    We present infrared observations of the supernova remnant G21.5-0.9 with the Very Large Telescope, the Canada-France-Hawaii Telescope and the Spitzer Space Telescope. Using the VLT/ISAAC camera equipped with a narrow-band [Fe II] 1.64 μm filter the entire pulsar wind nebula in SNR G21.5-0.9 was imaged. This led to detection of iron line-emitting material in the shape of a broken ring-like structure following the nebula's edge. The detected emission is limb-brightened. We also detect the compact nebula surrounding PSR J1833-1034, both through imaging with the CFHT/AOB-KIR instrument (K' band) and the IRAC camera (all bands) and also through polarimetric observations performed with VLT/ISAAC (Ks band). The emission from the compact nebula is highly polarised with an average value of the linear polarisation fraction PL^avg ≃ 0.47, and the swing of the electric vector across the nebula can be observed. The infrared spectrum of the compact nebula can be described as a power law of index αIR = 0.7 ± 0.3, and suggests that the spectrum flattens between the infrared and X-ray bands.

  5. Wiener filtering of surface EMG with a priori SNR estimation toward myoelectric control for neurological injury patients.

    PubMed

    Liu, Jie; Ying, Dongwen; Zhou, Ping

    2014-12-01

    Voluntary surface electromyogram (EMG) signals from neurological injury patients are often corrupted by involuntary background interference or spikes, imposing difficulties for myoelectric control. We present a novel framework to suppress involuntary background spikes during voluntary surface EMG recordings. The framework applies a Wiener filter to restore voluntary surface EMG signals based on tracking a priori signal to noise ratio (SNR) by using the decision-directed method. Semi-synthetic surface EMG signals contaminated by different levels of involuntary background spikes were constructed from a database of surface EMG recordings in a group of spinal cord injury subjects. After the processing, the onset detection of voluntary muscle activity was significantly improved against involuntary background spikes. The magnitude of voluntary surface EMG signals can also be reliably estimated for myoelectric control purpose. Compared with the previous sample entropy analysis for suppressing involuntary background spikes, the proposed framework is characterized by quick and simple implementation, making it more suitable for application in a myoelectric control system toward neurological injury rehabilitation. PMID:25443536

  6. A multiple model SNR/RCS likelihood ratio score for radar-based feature-aided tracking

    NASA Astrophysics Data System (ADS)

    Slocumb, Benjamin J.; Klusman, Michael E., III

    2005-09-01

    Most approaches to data association in target tracking use a likelihood-ratio based score for measurement-to-track and track-to-track matching. The classical approach uses a likelihood ratio based on kinematic data. Feature-aided tracking uses non-kinematic data to produce an "auxiliary score" that augments the kinematic score. This paper develops a nonkinematic likelihood ratio score based on statistical models for the signal-to-noise (SNR) and radar cross section (RCS) for use in narrowband radar tracking. The formulation requires an estimate of the target mean RCS, and a key challenge is the tracking of the mean RCS through significant "jumps" due to aspect dependencies. A novel multiple model approach is used track through the RCS jumps. Three solution are developed: one based on an α-filter, a second based on the median filter, and the third based on an IMM filter with a median pre-filter. Simulation results are presented that show the effectiveness of the multiple model approach for tracking through RCS transitions due to aspect-angle changes.

  7. Wiener Filtering of Surface EMG with a priori SNR Estimation Toward Myoelectric Control for Neurological Injury Patients

    PubMed Central

    Liu, Jie; Ying, Dongwen; Zhou, Ping

    2014-01-01

    Voluntary surface electromyogram (EMG) signals from neurological injury patients are often corrupted by involuntary background interference or spikes, imposing difficulties for myoelectric control. We present a novel framework to suppress involuntary background spikes during voluntary surface EMG recordings. The framework applies a Wiener filter to restore voluntary surface EMG signals based on tracking a priori signal to noise ratio (SNR) by using the decision-directed method. Semi-synthetic surface EMG signals contaminated by different levels of involuntary background spikes were constructed from a database of surface EMG recordings in a group of spinal cord injury subjects. After the processing, the onset detection of voluntary muscle activity was significantly improved against involuntary background spikes. The magnitude of voluntary surface EMG signals can also be reliably estimated for myoelectric control purpose. Compared with the previous sample entropy analysis for suppressing involuntary background spikes, the proposed framework is characterized by quick and simple implementation, making it more suitable for application in a myoelectric control system toward neurological injury rehabilitation. PMID:25443536

  8. An absence of ex-companion stars in the type Ia supernova remnant SNR 0509-67.5.

    PubMed

    Schaefer, Bradley E; Pagnotta, Ashley

    2012-01-12

    A type Ia supernova is thought to begin with the explosion of a white dwarf star. The explosion could be triggered by the merger of two white dwarfs (a 'double-degenerate' origin), or by mass transfer from a companion star (the 'single-degenerate' path). The identity of the progenitor is still controversial; for example, a recent argument against the single-degenerate origin has been widely rejected. One way to distinguish between the double- and single-degenerate progenitors is to look at the centre of a known type Ia supernova remnant to see whether any former companion star is present. A likely ex-companion star for the progenitor of the supernova observed by Tycho Brahe has been identified, but that claim is still controversial. Here we report that the central region of the supernova remnant SNR 0509-67.5 (the site of a type Ia supernova 400 ± 50 years ago, based on its light echo) in the Large Magellanic Cloud contains no ex-companion star to a visual magnitude limit of 26.9 (an absolute magnitude of M(V) = +8.4) within a region of radius 1.43 arcseconds. (This corresponds to the 3σ maximum distance to which a companion could have been 'kicked' by the explosion.) This lack of any ex-companion star to deep limits rules out all published single-degenerate models for this supernova. The only remaining possibility is that the progenitor of this particular type Ia supernova was a double-degenerate system. PMID:22237107

  9. An absence of ex-companion stars in the type Ia supernova remnant SNR 0509-67.5

    NASA Astrophysics Data System (ADS)

    Schaefer, Bradley E.; Pagnotta, Ashley

    2012-01-01

    A type Ia supernova is thought to begin with the explosion of a white dwarf star. The explosion could be triggered by the merger of two white dwarfs (a `double-degenerate' origin), or by mass transfer from a companion star (the `single-degenerate' path). The identity of the progenitor is still controversial; for example, a recent argument against the single-degenerate origin has been widely rejected. One way to distinguish between the double- and single-degenerate progenitors is to look at the centre of a known type Ia supernova remnant to see whether any former companion star is present. A likely ex-companion star for the progenitor of the supernova observed by Tycho Brahe has been identified, but that claim is still controversial. Here we report that the central region of the supernova remnant SNR 0509-67.5 (the site of a type Ia supernova 400 +/- 50 years ago, based on its light echo) in the Large Magellanic Cloud contains no ex-companion star to a visual magnitude limit of 26.9 (an absolute magnitude of MV = +8.4) within a region of radius 1.43 arcseconds. (This corresponds to the 3σ maximum distance to which a companion could have been `kicked' by the explosion.) This lack of any ex-companion star to deep limits rules out all published single-degenerate models for this supernova. The only remaining possibility is that the progenitor of this particular type Ia supernova was a double-degenerate system.

  10. An absence of ex-companion stars in the type Ia supernova remnant SNR 0509-67.5.

    PubMed

    Schaefer, Bradley E; Pagnotta, Ashley

    2012-01-11

    A type Ia supernova is thought to begin with the explosion of a white dwarf star. The explosion could be triggered by the merger of two white dwarfs (a 'double-degenerate' origin), or by mass transfer from a companion star (the 'single-degenerate' path). The identity of the progenitor is still controversial; for example, a recent argument against the single-degenerate origin has been widely rejected. One way to distinguish between the double- and single-degenerate progenitors is to look at the centre of a known type Ia supernova remnant to see whether any former companion star is present. A likely ex-companion star for the progenitor of the supernova observed by Tycho Brahe has been identified, but that claim is still controversial. Here we report that the central region of the supernova remnant SNR 0509-67.5 (the site of a type Ia supernova 400 ± 50 years ago, based on its light echo) in the Large Magellanic Cloud contains no ex-companion star to a visual magnitude limit of 26.9 (an absolute magnitude of M(V) = +8.4) within a region of radius 1.43 arcseconds. (This corresponds to the 3σ maximum distance to which a companion could have been 'kicked' by the explosion.) This lack of any ex-companion star to deep limits rules out all published single-degenerate models for this supernova. The only remaining possibility is that the progenitor of this particular type Ia supernova was a double-degenerate system.

  11. Detection of X-Ray Line Emission from the Shell of SNR B0540-69.3 with XMM-Newton RGS

    NASA Technical Reports Server (NTRS)

    vanderHeyden, K. J.; Cottam, J.; Paerels, F.; Kaastra, J. S.; Branduardi-Raymont, G.

    2000-01-01

    We present X-ray observations of PSR 0540-69.3 with the XMM-Newton observatory. The spectra obtained with the Reflection Grating Spectrometer reveal, for the first time, emission from ionized species of O, Ne and Fe originating from the SNR shell. Analysis of the emission line spectrum allows us to derive estimates of the temperature, ionization timescale, abundances, location, and velocity of the emitting gas.

  12. Extensive air showers generated by gamma-quanta from Geminga and Tycho's SNR at energy range 1 30 TeV

    NASA Astrophysics Data System (ADS)

    Sinitsyna, V. G.; Arsov, T. P.; Alaverdian, A. Y.; Borisov, S. S.; Musin, F. I.; Nikolsky, S. I.; Sinitsyna, V. Y.; Platonov, G. F.

    2006-01-01

    The gamma-quantum emitting objects in our Galaxy are supernova remnants and binary. The observed results of gamma-quantum sources Tycho Brahe and Geminga by the SHALON gamma-telescope are presented. The integral spectra of events from the source - k and background events, observing simultaneously with source's events - k, and the source image are presented. The energy spectra of Tycho's SNR and Geminga supernova remnant F(E>0.8TeV)˜E are harder than the Crab Nebula spectrum. Tycho's SNR has long been considered as a candidate cosmic ray source in Northern Hemisphere. A non-linear kinetic model of cosmic ray acceleration in supernova remnants was used for Tycho's SNR. The expected π°-decay gamma-quanta flux F˜Eγ-1 extends up to ˜30TeV, whereas the Inverse Compton gamma-ray flux has a cut-off above a few TeV. So, the detection of gamma-rays at energies of ˜10-30TeV by SHALON is evidence for hadron origin.

  13. An OH(1720 MHz) Maser and a Nonthermal Radio Source in Sgr B2(M): An SNR-Molecular Cloud Interaction Site?

    NASA Astrophysics Data System (ADS)

    Yusef-Zadeh, F.; Cotton, W.; Wardle, M.; Intema, H.

    2016-03-01

    Sgr B2 is a well-known star-forming molecular cloud complex in the Galactic center region showing evidence of high energy activity as traced by the Kα neutral Fe i line at 6.4 keV, as well as GeV and TeV γ-ray emission. Here, we present Very Large Array and GMRT observations with respective resolutions of ≈ 3\\buildrel{\\prime\\prime}\\over{.} 5× 1\\buildrel{\\prime\\prime}\\over{.} 2 and 25\\prime\\prime × 25\\prime\\prime and report the detection of an OH(1720 MHz) maser, with no accompanying OH 1665, 1667, and 1612 MHz maser emission. The maser coincides with a 150 MHz nonthermal radio source in Sgr B2(M). This rare class of OH(1720 MHz) masers or the so-called supernova remnant (SNR) masers, with no main line transitions, trace shocked gas and signal the interaction of an expanding SNR with a molecular cloud. We interpret the 150 MHz radio source as either the site of a SNR-molecular gas interaction or a wind-wind collision in a massive binary system. The interaction of the molecular cloud and the nonthermal source enhances the cosmic-ray ionization rate, allows the diffusion of cosmic rays into the cloud, and produces the variable 6.4 keV line, GeV, and TeV γ-ray emission from Sgr B2(M). The cosmic-ray electron interaction with the gas in the Galactic center can not only explain the measured high values of cosmic-ray ionization and heating rates but also contribute to nonthermal bremsstrahlung continuum emission, all of which are consistent with observations.

  14. Interstellar protons in the TeV γ-ray SNR HESS J1731-347: Possible evidence for the coexistence of hadronic and leptonic γ-rays

    SciTech Connect

    Fukuda, T.; Yoshiike, S.; Sano, H.; Torii, K.; Yamamoto, H.; Fukui, Y.; Acero, F.

    2014-06-10

    HESS J1731-347 (G353.6-0.7) is one of the TeV γ-ray supernova remnants (SNRs) that shows the shell-like morphology. We have made a new analysis of the interstellar protons toward the SNR by using both the {sup 12}CO(J = 1-0) and H I data sets. The results indicate that the TeV γ-ray shell shows significant spatial correlation with the interstellar protons at a velocity range from –90 km s{sup –1} to –75 km s{sup –1}. The total mass of the interstellar medium (ISM) protons is estimated to be 6.4 × 10{sup 4} M {sub ☉}, 25% of which is atomic gas, and the distance corresponding to the velocity range is ∼5.2 kpc, a factor of 2 larger than the previous figure, 3 kpc. We have identified the cold H I gas observed as self-absorption which shows significant correspondence with the northeastern γ-ray peak. While the good correspondence between the ISM protons and TeV γ-rays in the north of the SNR lends support to the hadronic scenario for the TeV γ-rays, the southern part of the shell shows a break in the correspondence; in particular, the southwestern rim of the SNR shell shows a significant decrease of the interstellar protons by a factor of two. We argue that this discrepancy can be explained due to leptonic γ-rays because this region coincides well with the bright shell that emits non-thermal radio continuum emission and non-thermal X-rays, suggesting that the γ-rays of HESS J1713-347 consist of both the hadronic and leptonic components. The leptonic contribution corresponds to ∼20% of the total γ-rays.

  15. Interstellar Protons in the TeV γ-Ray SNR HESS J1731-347: Possible Evidence for the Coexistence of Hadronic and Leptonic γ-Rays

    NASA Astrophysics Data System (ADS)

    Fukuda, T.; Yoshiike, S.; Sano, H.; Torii, K.; Yamamoto, H.; Acero, F.; Fukui, Y.

    2014-06-01

    HESS J1731-347 (G353.6-0.7) is one of the TeV γ-ray supernova remnants (SNRs) that shows the shell-like morphology. We have made a new analysis of the interstellar protons toward the SNR by using both the 12CO(J = 1-0) and H I data sets. The results indicate that the TeV γ-ray shell shows significant spatial correlation with the interstellar protons at a velocity range from -90 km s-1 to -75 km s-1. The total mass of the interstellar medium (ISM) protons is estimated to be 6.4 × 104 M ⊙, 25% of which is atomic gas, and the distance corresponding to the velocity range is ~5.2 kpc, a factor of 2 larger than the previous figure, 3 kpc. We have identified the cold H I gas observed as self-absorption which shows significant correspondence with the northeastern γ-ray peak. While the good correspondence between the ISM protons and TeV γ-rays in the north of the SNR lends support to the hadronic scenario for the TeV γ-rays, the southern part of the shell shows a break in the correspondence; in particular, the southwestern rim of the SNR shell shows a significant decrease of the interstellar protons by a factor of two. We argue that this discrepancy can be explained due to leptonic γ-rays because this region coincides well with the bright shell that emits non-thermal radio continuum emission and non-thermal X-rays, suggesting that the γ-rays of HESS J1713-347 consist of both the hadronic and leptonic components. The leptonic contribution corresponds to ~20% of the total γ-rays.

  16. Melker Meilensteine auf dem Weg in ein naturwissenschaftliches Zeitalter - Glanzlichter der Ausstellung zum Internationalen Astronomiejahr 2009 in der Melker Stiftsbibliothek.

    NASA Astrophysics Data System (ADS)

    Beck, Paul G.; Zotti, Georg

    2009-06-01

    Das Mittelalter wird weithin als die dunkle Epoche in der Geschichte der Europäischen Wissenschaften betrachtet, und insbesondere das Leben in den Klöstern galt lange Zeit als frei von jeglichem Interesse für Naturwissenschaften abseits der Medizin. Im Mittelalter galt die Astronomie bloß als Mittel zum Zweck, um religiöse und zivile Kalender erstellen zu können. Durch den Bestand der Handschriftenkammer der Melker Stiftsbibliothek eröffnet sich uns eine neue Sichtweise auf das gegen Ende des Mittelalters wachsende Interesse an den Naturwissenschaften. Dies wurde durch die starke Aufwertung der Klosterbibliothek im Rahmen der 'Melker Reform' im 15. Jahrhundert noch weiter verstärkt. Diese Epoche fällt mit der Frühphase der Universität Wien und der 'ersten Wiener Schule der Astronomie' zusammen. Dieser Artikel beleuchtet ausgewählte astronomischen Werke in der Melker Stiftsbibliothek zwischen dem frühen 9 und dem 18. Jahrhundert. Einen Schwerpunkt stellt das Wirken der Wiener Schule der Astronomie dar, wobei wir u.a. die Melker Abschrift von Peuerbachs Gutachten über den Kometen von 1456 sowie die im Stift Melk durchgeführte Beobachtung der Mondfinsternis von 1457 durch Regiomontanus und Peuerbach beleuchten. Dieser Beitrag ist der einführende Übersichtsartikel zum Ausstellungsprojekt in der Melker Stiftsbibliothek im Rahmen des Internationalen Jahres der Astronomie 2009. The medieval period is commonly seen as a dark epoch for science in Europe. Especially monasteries were seen as institutions without interest in natural sciences except for medicine. Astronomy was allegedly only a tool to construct religious and civil calendars. The inventory of the medieval manuscript collection of the library of the Abbey of Melk allows a new view on the growing interest in the exact sciences towards the end of the medieval ages. This interest was intensified through the increased importance of the monastery library due to the monastery reform

  17. The diffuse source at the center of LMC SNR 0509–67.5 is a background galaxy at z = 0.031

    SciTech Connect

    Pagnotta, Ashley; Walker, Emma S.; Schaefer, Bradley E.

    2014-06-20

    Type Ia supernovae (SNe Ia) are well-known for their use in the measurement of cosmological distances, but our continuing lack of concrete knowledge about their progenitor stars is both a matter of debate and a source of systematic error. In our attempts to answer this question, we presented unambiguous evidence that LMC SNR 0509–67.5, the remnant of an SN Ia that exploded in the Large Magellanic Cloud 400 ± 50 yr ago, did not have any point sources (stars) near the site of the original supernova explosion, from which we concluded that this particular supernova must have had a progenitor system consisting of two white dwarfs. There is, however, evidence of nebulosity near the center of the remnant, which could have been left over detritus from the less massive WD, or could have been a background galaxy unrelated to the supernova explosion. We obtained long-slit spectra of the central nebulous region using GMOS on Gemini South to determine which of these two possibilities is correct. The spectra show Hα emission at a redshift of z = 0.031, which implies that the nebulosity in the center of LMC SNR 0509–67.5 is a background galaxy, unrelated to the supernova.

  18. A new framework for particle detection in low-SNR fluorescence live-cell images and its application for improved particle tracking.

    PubMed

    Yang, Lei; Qiu, Zhen; Greenaway, Alan H; Lu, Weiping

    2012-07-01

    Image denoising and signal enhancement are two common steps to improve particle contrast for detection in low-signal-to-noise ratio (SNR) fluorescence live-cell images. However, denoising may oversmooth features of interest, particularly weak features, leading to false negative detection. Here, we propose a robust framework for particle detection in which image denoising in the grayscale image is not needed, so avoiding image oversmoothing. A key to our approach is the new development of a particle enhancement filter based on the recently proposed particle probability image to obtain significantly enhanced particle features and greatly suppressed background in low-SNR and low-contrast environments. The new detection method is formed by combining foreground and background markers with watershed transform operating in both particle probability and grayscale spaces; dynamical switchings between the two spaces can optimally make use the information in images for accurate determination of particle position, size, and intensity. We further develop the interacting multiple mode filter for particle motion modeling and data association by incorporating the extra information obtained from our particle detector to enhance the efficiency of multiple particle tracking. We find that our methods lead to significant improvements in particle detection and tracking efficiency in fluorescence live-cell applications. PMID:22552546

  19. New constraints on the TeV SNR shells RX J1713.7-3946 and HESS J1731-347

    NASA Astrophysics Data System (ADS)

    Puehlhofer, G.; Eger, P.; Doroshenko, V.; Cui, Y.; H. E. S. S. Collaboration

    2016-06-01

    Resolved TeV-emitting supernova remnants remain a small and precious class of sources to study cosmic ray acceleration in SNRs. We present new multi-wavelength results of the two prominent objects RX J1713.7-3946 and HESS J1731-347. For RX J1713.7-3946, extensive new H.E.S.S. data have permitted to study the nature of the TeV-emitting CR particles through improved broadband spectral studies, as well as through detailed investigations of morphological differences between TeV gamma-rays and X-rays. Concerning HESS J1731-347, the TeV morphology of the object and its surroundings has been studied using cosmic ray acceleration simulations of the object. The SNR also hosts a luminous X-ray emitting central compact object (CCO). Investigations of the CCO in X-rays and in the infrared have permitted to set interesting constraints on the SNR and its progenitor.

  20. A new framework for particle detection in low-SNR fluorescence live-cell images and its application for improved particle tracking.

    PubMed

    Yang, Lei; Qiu, Zhen; Greenaway, Alan H; Lu, Weiping

    2012-07-01

    Image denoising and signal enhancement are two common steps to improve particle contrast for detection in low-signal-to-noise ratio (SNR) fluorescence live-cell images. However, denoising may oversmooth features of interest, particularly weak features, leading to false negative detection. Here, we propose a robust framework for particle detection in which image denoising in the grayscale image is not needed, so avoiding image oversmoothing. A key to our approach is the new development of a particle enhancement filter based on the recently proposed particle probability image to obtain significantly enhanced particle features and greatly suppressed background in low-SNR and low-contrast environments. The new detection method is formed by combining foreground and background markers with watershed transform operating in both particle probability and grayscale spaces; dynamical switchings between the two spaces can optimally make use the information in images for accurate determination of particle position, size, and intensity. We further develop the interacting multiple mode filter for particle motion modeling and data association by incorporating the extra information obtained from our particle detector to enhance the efficiency of multiple particle tracking. We find that our methods lead to significant improvements in particle detection and tracking efficiency in fluorescence live-cell applications.

  1. Untersuchungen zum hydraulischen Grundbruch in Baugruben in homogenen Böden

    NASA Astrophysics Data System (ADS)

    Koltuk, Serdar; Fernandez-Steeger, Tomas M.; Azzam, Rafig

    2016-09-01

    In this study, two problems are discussed with respect to hydraulic heave. Firstly, the verification of safety against hydraulic heave according to DIN EN 1997-1 (2014-03) yields different results depending on the considered limit state conditions. It is demonstrated that this problem can be solved by using hydraulic gradients as a parameter for the limit state condition. Secondly, the form of a potential failure body appearing in three-dimensional groundwater models is unknown. Based on numerical analyses, it has been shown that an average hydraulic gradient that is determined by using an assumed three-dimensional failure body with the width suggested by Terzaghi for two-dimensional cases leads to a quicksand condition in an infinitesimal soil column directly adjacent to the wall, when its value is equal to the critical hydraulic gradient of the soil. The model tests show that Terzaghi's method or quicksand condition refers to certain deformations in an excavation base. The hydraulic gradient required for the first sign of a quicksand condition in loose sands may be lower than the theoretically required hydraulic gradient, whereas it is higher in dense sands.

  2. SNS shielding analyses overview

    SciTech Connect

    Popova, Irina; Gallmeier, Franz; Iverson, Erik B; Lu, Wei; Remec, Igor

    2015-01-01

    This paper gives an overview on on-going shielding analyses for Spallation Neutron Source. Presently, the most of the shielding work is concentrated on the beam lines and instrument enclosures to prepare for commissioning, save operation and adequate radiation background in the future. There is on-going work for the accelerator facility. This includes radiation-protection analyses for radiation monitors placement, designing shielding for additional facilities to test accelerator structures, redesigning some parts of the facility, and designing test facilities to the main accelerator structure for component testing. Neutronics analyses are required as well to support spent structure management, including waste characterisation analyses, choice of proper transport/storage package and shielding enhancement for the package if required.

  3. Spacelab Charcoal Analyses

    NASA Technical Reports Server (NTRS)

    Slivon, L. E.; Hernon-Kenny, L. A.; Katona, V. R.; Dejarme, L. E.

    1995-01-01

    This report describes analytical methods and results obtained from chemical analysis of 31 charcoal samples in five sets. Each set was obtained from a single scrubber used to filter ambient air on board a Spacelab mission. Analysis of the charcoal samples was conducted by thermal desorption followed by gas chromatography/mass spectrometry (GC/MS). All samples were analyzed using identical methods. The method used for these analyses was able to detect compounds independent of their polarity or volatility. In addition to the charcoal samples, analyses of three Environmental Control and Life Support System (ECLSS) water samples were conducted specifically for trimethylamine.

  4. Discovery of the VHE gamma-ray source HESS J1832-093 in the vicinity of SNR G22.7-0.2

    NASA Astrophysics Data System (ADS)

    HESS Collaboration; Abramowski, A.; Acero, F.; Aharonian, F.; Ait Benkhali, F.; Akhperjanian, A. G.; Angüner, E.; Anton, G.; Balenderan, S.; Balzer, A.; Barnacka, A.; Becherini, Y.; Becker Tjus, J.; Bernlöhr, K.; Birsin, E.; Bissaldi, E.; Biteau, J.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bordas, P.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Carrigan, S.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Chalme-Calvet, R.; Chaves, R. C. G.; Cheesebrough, A.; Chrétien, M.; Clapson, A.-C.; Colafrancesco, S.; Cologna, G.; Conrad, J.; Couturier, C.; Cui, Y.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; deWilt, P.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; Drury, L. O'C.; Dubus, G.; Dutson, K.; Dyks, J.; Dyrda, M.; Edwards, T.; Egberts, K.; Eger, P.; Espigat, P.; Farnier, C.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fernandez, D.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gajdus, M.; Gallant, Y. A.; Garrigoux, T.; Giavitto, G.; Giebels, B.; Glicenstein, J. F.; Grondin, M.-H.; Grudzińska, M.; Häffner, S.; Hahn, J.; Harris, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hervet, O.; Hillert, A.; Hinton, J. A.; Hofmann, W.; Hofverberg, P.; Holler, M.; Horns, D.; Jacholkowska, A.; Jahn, C.; Jamrozy, M.; Janiak, M.; Jankowsky, F.; Jung, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Khélifi, B.; Kieffer, M.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Kolitzus, D.; Komin, Nu.; Kosack, K.; Krakau, S.; Krayzel, F.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lefaucheur, J.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Lennarz, D.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; McComb, T. J. L.; Méhault, J.; Meintjes, P. J.; Menzler, U.; Meyer, M.; Moderski, R.; Mohamed, M.; Moulin, E.; Murach, T.; Naumann, C. L.; de Naurois, M.; Niemiec, J.; Nolan, S. J.; Oakes, L.; Ohm, S.; de Oña Wilhelmi, E.; Opitz, B.; Ostrowski, M.; Oya, I.; Panter, M.; Parsons, R. D.; Paz Arribas, M.; Pekeur, N. W.; Pelletier, G.; Perez, J.; Petrucci, P.-O.; Peyaud, B.; Pita, S.; Poon, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Raue, M.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Rob, L.; Romoli, C.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Sanchez, D. A.; Santangelo, A.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Sol, H.; Spengler, G.; Spies, F.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Szostek, A.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tluczykont, M.; Trichard, C.; Valerius, K.; van Eldik, C.; van Soelen, B.; Vasileiadis, G.; Venter, C.; Viana, A.; Vincent, P.; Völk, H. J.; Volpe, F.; Vorster, M.; Vuillaume, T.; Wagner, S. J.; Wagner, P.; Ward, M.; Weidinger, M.; Weitzel, Q.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Zabalza, V.; Zacharias, M.; Zajczyk, A.; Zdziarski, A. A.; Zech, A.; Zechlin, H.-S.

    2015-01-01

    The region around the supernova remnant (SNR) W41 contains several TeV sources and has prompted the HESS Collaboration to perform deep observations of this field of view. This resulted in the discovery of the new very high energy (VHE) source HESS J1832-093, at the position {RA=18^h 32^m 50^s ± 3^s_{stat} ± 2^s_{syst}}, {Dec=-9*deg;22'36" ± 32"}_{stat} ± 20^' '}_{syst} (J2000)}, spatially coincident with a part of the radio shell of the neighbouring remnant G22.7-0.2. The photon spectrum is well described by a power law of index Γ = 2.6 ± 0.3stat ± 0.1syst and a normalization at 1 TeV of Φ _0=(4.8 ± 0.8_stat± 1.0_syst) × 10^{-13} cm ^{-2} s^{-1} TeV^{-1}. The location of the gamma-ray emission on the edge of the SNR rim first suggested a signature of escaping cosmic rays illuminating a nearby molecular cloud. Then a dedicated XMM-Newton observation led to the discovery of a new X-ray point source spatially coincident with the TeV excess. Two other scenarios were hence proposed to identify the nature of HESS J1832-093. Gamma-rays from inverse Compton radiation in the framework of a pulsar wind nebula scenario or the possibility of gamma-ray production within a binary system are therefore also considered. Deeper multiwavelength observations will help to shed new light on this intriguing VHE source.

  5. Wavelet Analyses and Applications

    ERIC Educational Resources Information Center

    Bordeianu, Cristian C.; Landau, Rubin H.; Paez, Manuel J.

    2009-01-01

    It is shown how a modern extension of Fourier analysis known as wavelet analysis is applied to signals containing multiscale information. First, a continuous wavelet transform is used to analyse the spectrum of a nonstationary signal (one whose form changes in time). The spectral analysis of such a signal gives the strength of the signal in each…

  6. Apollo 14 microbial analyses

    NASA Technical Reports Server (NTRS)

    Taylor, G. R.

    1972-01-01

    Extensive microbiological analyses that were performed on the Apollo 14 prime and backup crewmembers and ancillary personnel are discussed. The crewmembers were subjected to four separate and quite different environments during the 137-day monitoring period. The relation between each of these environments and observed changes in the microflora of each astronaut are presented.

  7. Information Omitted From Analyses.

    PubMed

    2015-08-01

    In the Original Article titled “Higher- Order Genetic and Environmental Structure of Prevalent Forms of Child and Adolescent Psychopathology” published in the February 2011 issue of JAMA Psychiatry (then Archives of General Psychiatry) (2011;68[2]:181-189), there were 2 errors. Although the article stated that the dimensions of psychopathology were measured using parent informants for inattention, hyperactivity-impulsivity, and oppositional defiant disorder, and a combination of parent and youth informants for conduct disorder, major depression, generalized anxiety disorder, separation anxiety disorder, social phobia, specific phobia, agoraphobia, and obsessive-compulsive disorder, all dimensional scores used in the reported analyses were actually based on parent reports of symptoms; youth reports were not used. In addition, whereas the article stated that each symptom dimension was residualized on age, sex, age-squared, and age by sex, the dimensions actually were only residualized on age, sex, and age-squared. All analyses were repeated using parent informants for inattention, hyperactivity-impulsivity, and oppositional defiant disorder, and a combination of parent and youth informants for conduct disorder,major depression, generalized anxiety disorder, separation anxiety disorder, social phobia, specific phobia, agoraphobia, and obsessive-compulsive disorder; these dimensional scores were residualized on age, age-squared, sex, sex by age, and sex by age-squared. The results of the new analyses were qualitatively the same as those reported in the article, with no substantial changes in conclusions. The only notable small difference was that major depression and generalized anxiety disorder dimensions had small but significant loadings on the internalizing factor in addition to their substantial loadings on the general factor in the analyses of both genetic and non-shared covariances in the selected models in the new analyses. Corrections were made to the

  8. Vom Urknall zum Durchknall

    NASA Astrophysics Data System (ADS)

    Unzicker, Alexander

    Lautstarker Applaus erhob sich im Salon III/IV des Marriott-Hotels von Crystal City im amerikanischen Bundesstaat Virginia. In dem überfüllten Konferenzraum starrten alle wie gebannt auf die Leinwand, wo nicht mehr zu sehen war als ein nüchternes Diagramm aus zahlreichen Punkten und einer geschwungenen Kurve. Nureine eigenartige Personengruppe konnte sich davon zu Emotionen hinreißen lassen - Physiker auf der Jahrestagung der Astronomischen Gesellschaft, die ihren Begeisterungssturm noch minutenlang fortsetzten. Was war geschehen? Die im Diagramm aufgetragenen Daten bestätigten mit einer nie da gewesenen Genauigkeit ein fundamentales Naturgesetz zur Wärmeabstrahlung von heißen Körpern. 1900 von Max Planck entdeckt, leuchtete es nun in geradezu mathematischer Reinheit auf. Noch sensationeller war der Ursprung der Daten - Mikrowellensignale verschiedener Frequenzen, die nicht aus einem irdischen Labor stammten, sondern von einem heißen Urzustand des Universums! Ein Feuerball aus Wasserstoff und Helium, noch ohne jegliche Strukturen, die irgendwann Leben ermöglichen sollten, ließ damals seinem Licht freien Lauf. Mehr als zehn Milliarden Jahre war es bis zu den Detektoren des vom Menschen gebauten Satelliten COBE unterwegs, der wenige Tage zuvor die Daten übertragen hatte. Wenn ich das alles wie einen Film in meiner Vorstellung ablaufen lasse, bekomme ich immer eine Gänsehaut, als würde ich die inzwischen extrem abgekühlte Strahlung tatsächlich spüren. Ihre Gleichverteilung im Raum macht uns auch deutlich, dass wir uns nicht einbilden dürfen, an einem besonderen Ort im Universum zu leben - intelligente Aliens könnten sich seitdem überall entwickelt haben! Sollten sie - was nicht wahrscheinlich ist - uns wirklich von Zeit zu Zeit über die Schulter schauen, dann hätten sie an jenem Nachmittag des 13. Januar 1990, als der Vortrag stattfand, bestimmt anerkennend mit ihrem großen Kopf genickt.

  9. LDEF Satellite Radiation Analyses

    NASA Technical Reports Server (NTRS)

    Armstrong, T. W.; Colborn, B. L.

    1996-01-01

    Model calculations and analyses have been carried out to compare with several sets of data (dose, induced radioactivity in various experiment samples and spacecraft components, fission foil measurements, and LET spectra) from passive radiation dosimetry on the Long Duration Exposure Facility (LDEF) satellite, which was recovered after almost six years in space. The calculations and data comparisons are used to estimate the accuracy of current models and methods for predicting the ionizing radiation environment in low earth orbit. The emphasis is on checking the accuracy of trapped proton flux and anisotropy models.

  10. LDEF Satellite Radiation Analyses

    NASA Technical Reports Server (NTRS)

    Armstrong, T. W.; Colborn, B. L.

    1996-01-01

    This report covers work performed by Science Applications International Corporation (SAIC) under contract NAS8-39386 from the NASA Marshall Space Flight Center entitled LDEF Satellite Radiation Analyses. The basic objective of the study was to evaluate the accuracy of present models and computational methods for defining the ionizing radiation environment for spacecraft in Low Earth Orbit (LEO) by making comparisons with radiation measurements made on the Long Duration Exposure Facility (LDEF) satellite, which was recovered after almost six years in space. The emphasis of the work here is on predictions and comparisons with LDEF measurements of induced radioactivity and Linear Energy Transfer (LET) measurements. These model/data comparisons have been used to evaluate the accuracy of current models for predicting the flux and directionality of trapped protons for LEO missions.

  11. EEG analyses with SOBI.

    SciTech Connect

    Glickman, Matthew R.; Tang, Akaysha

    2009-02-01

    The motivating vision behind Sandia's MENTOR/PAL LDRD project has been that of systems which use real-time psychophysiological data to support and enhance human performance, both individually and of groups. Relevant and significant psychophysiological data being a necessary prerequisite to such systems, this LDRD has focused on identifying and refining such signals. The project has focused in particular on EEG (electroencephalogram) data as a promising candidate signal because it (potentially) provides a broad window on brain activity with relatively low cost and logistical constraints. We report here on two analyses performed on EEG data collected in this project using the SOBI (Second Order Blind Identification) algorithm to identify two independent sources of brain activity: one in the frontal lobe and one in the occipital. The first study looks at directional influences between the two components, while the second study looks at inferring gender based upon the frontal component.

  12. Network Class Superposition Analyses

    PubMed Central

    Pearson, Carl A. B.; Zeng, Chen; Simha, Rahul

    2013-01-01

    Networks are often used to understand a whole system by modeling the interactions among its pieces. Examples include biomolecules in a cell interacting to provide some primary function, or species in an environment forming a stable community. However, these interactions are often unknown; instead, the pieces' dynamic states are known, and network structure must be inferred. Because observed function may be explained by many different networks (e.g., for the yeast cell cycle process [1]), considering dynamics beyond this primary function means picking a single network or suitable sample: measuring over all networks exhibiting the primary function is computationally infeasible. We circumvent that obstacle by calculating the network class ensemble. We represent the ensemble by a stochastic matrix , which is a transition-by-transition superposition of the system dynamics for each member of the class. We present concrete results for derived from Boolean time series dynamics on networks obeying the Strong Inhibition rule, by applying to several traditional questions about network dynamics. We show that the distribution of the number of point attractors can be accurately estimated with . We show how to generate Derrida plots based on . We show that -based Shannon entropy outperforms other methods at selecting experiments to further narrow the network structure. We also outline an experimental test of predictions based on . We motivate all of these results in terms of a popular molecular biology Boolean network model for the yeast cell cycle, but the methods and analyses we introduce are general. We conclude with open questions for , for example, application to other models, computational considerations when scaling up to larger systems, and other potential analyses. PMID:23565141

  13. Network class superposition analyses.

    PubMed

    Pearson, Carl A B; Zeng, Chen; Simha, Rahul

    2013-01-01

    Networks are often used to understand a whole system by modeling the interactions among its pieces. Examples include biomolecules in a cell interacting to provide some primary function, or species in an environment forming a stable community. However, these interactions are often unknown; instead, the pieces' dynamic states are known, and network structure must be inferred. Because observed function may be explained by many different networks (e.g., ≈ 10(30) for the yeast cell cycle process), considering dynamics beyond this primary function means picking a single network or suitable sample: measuring over all networks exhibiting the primary function is computationally infeasible. We circumvent that obstacle by calculating the network class ensemble. We represent the ensemble by a stochastic matrix T, which is a transition-by-transition superposition of the system dynamics for each member of the class. We present concrete results for T derived from boolean time series dynamics on networks obeying the Strong Inhibition rule, by applying T to several traditional questions about network dynamics. We show that the distribution of the number of point attractors can be accurately estimated with T. We show how to generate Derrida plots based on T. We show that T-based Shannon entropy outperforms other methods at selecting experiments to further narrow the network structure. We also outline an experimental test of predictions based on T. We motivate all of these results in terms of a popular molecular biology boolean network model for the yeast cell cycle, but the methods and analyses we introduce are general. We conclude with open questions for T, for example, application to other models, computational considerations when scaling up to larger systems, and other potential analyses. PMID:23565141

  14. SNR G349.7+0.2: A γ-RAY SOURCE IN THE FAR 3 kpc ARM OF THE GALACTIC CENTER

    SciTech Connect

    Tian, W. W.; Leahy, D. A.

    2014-03-01

    We analyze the H I absorption profile for TeV supernova remnant (SNR) G349.7+0.2 based on updated knowledge of the inner Galaxy's structure. We significantly revise its kinematic distance from the previous ∼22 kpc to ∼11.5 kpc, indicating it is in the far 3 kpc arm of the Galactic center. We give a revised age of ∼1800 yr for G349.7+0.2 which has a low explosion energy of ∼2.5 × 10{sup 50} erg. This removes G349.7+0.2 from the set of brightest SNRs in radio and X-ray to γ-ray wavebands and helps us to better understand γ-ray emission originating from this remnant. However, one needs to use caution when discussing old kinematic distances of Galactic objects (e.g., SNRs, pulsars, and H II regions) in the range of –12° ≤ l ≤ 12° with distance estimates of ≥5.5 kpc.

  15. NOAA's National Snow Analyses

    NASA Astrophysics Data System (ADS)

    Carroll, T. R.; Cline, D. W.; Olheiser, C. M.; Rost, A. A.; Nilsson, A. O.; Fall, G. M.; Li, L.; Bovitz, C. T.

    2005-12-01

    NOAA's National Operational Hydrologic Remote Sensing Center (NOHRSC) routinely ingests all of the electronically available, real-time, ground-based, snow data; airborne snow water equivalent data; satellite areal extent of snow cover information; and numerical weather prediction (NWP) model forcings for the coterminous U.S. The NWP model forcings are physically downscaled from their native 13 km2 spatial resolution to a 1 km2 resolution for the CONUS. The downscaled NWP forcings drive an energy-and-mass-balance snow accumulation and ablation model at a 1 km2 spatial resolution and at a 1 hour temporal resolution for the country. The ground-based, airborne, and satellite snow observations are assimilated into the snow model's simulated state variables using a Newtonian nudging technique. The principle advantages of the assimilation technique are: (1) approximate balance is maintained in the snow model, (2) physical processes are easily accommodated in the model, and (3) asynoptic data are incorporated at the appropriate times. The snow model is reinitialized with the assimilated snow observations to generate a variety of snow products that combine to form NOAA's NOHRSC National Snow Analyses (NSA). The NOHRSC NSA incorporate all of the available information necessary and available to produce a "best estimate" of real-time snow cover conditions at 1 km2 spatial resolution and 1 hour temporal resolution for the country. The NOHRSC NSA consist of a variety of daily, operational, products that characterize real-time snowpack conditions including: snow water equivalent, snow depth, surface and internal snowpack temperatures, surface and blowing snow sublimation, and snowmelt for the CONUS. The products are generated and distributed in a variety of formats including: interactive maps, time-series, alphanumeric products (e.g., mean areal snow water equivalent on a hydrologic basin-by-basin basis), text and map discussions, map animations, and quantitative gridded products

  16. A 430 mW 16 b 170 MS/s CMOS pipelined ADC with 77.2 dB SNR and 97.6 dB SFDR

    NASA Astrophysics Data System (ADS)

    Hui, Zhang; Dan, Li; Lei, Wan; Hui, Zhang; Haijun, Wang; Yuan, Gao; Feili, Zhu; Ziqi, Wang; Xuexin, Ding

    2016-03-01

    A 16-bit 170 MS/s pipelined ADC implemented in 0.18 μm CMOS process is presented in this paper. An improved digital calibration method and a linearized sampling front-end are employed to achieve a high SFDR. The enlarged full scale range makes it possible to obtain a high SNR with smaller sampling capacitors, thus achieving higher speed and low power. This ADC attains an SNR of 77.2 dBFS, an SFDR of 97.6 dBc for a 10 MHz input signal, while preserving an SFDR > 80 dBc up to 300 MHz input frequency. The ADC consumes 430 mW from a 1.8 V supply and occupies a 17 mm2 active area. Project supported by the National Science and Technology Major Project (No. 2009ZX01034-002-001-016).

  17. PSR J2022 plus 3842: An Energetic Radio and X-Ray Pulsar Associated with SNR G76.9 plus 1.0

    NASA Technical Reports Server (NTRS)

    Arzoumanian, Z.; Gotthelf, E. V.; Ransom, S. M.; Kothes, R.; Landecker, T. L.

    2010-01-01

    We present Chandra X-ray Observatory, Robert C. Byrd Green Bank Radio Telescope (GBT), and Rossi X-ray Timing Explorer (RXTE) observations directed toward the radio supernova remnant (SNR) G76.9+1.0. The Chandra investigation reveals a hard, unresolved X-ray source coincident with the midpoint of the double-lobed radio morphology and surrounded by faint, compact X-ray nebulosity. These features suggest that an energetic neutron star is powering a pulsar wind nebula (PWN) seen in synchrotron emission. Indeed, the spatial relationship of the X-ray and radio emissions is remarkably similar to the extended emission around the Vela pulsar. A follow-up pulsation search with the GBT uncovered a highly-dispersed (DM = 427 +/- 1 pc/cu cm) and highly-scattered pulsar with a period of 24 ms. Its subsequently measured spin-down rate implies a characteristic age T(sub c) = 8.9 kyr, making PSR J2022+3842 the most rapidly rotating young radio pulsar known. With a spin-down luminosity E = 1.2 x 10(exp 38) erg/s, it is the second-most energetic Galactic pulsar known, after the Crab pulsar. The 24-ms pulsations have also been detected in the RXTE observation; the combined Chandra and RXTE spectral fit suggests that the Chandra point-source emission is virtually 100% pulsed. The 2-16 keV spectrum of the narrow (0.06 cycles FWHM) pulse is well-fitted by an absorbed power-law model with column density N(sub H) = (1.7 +/- 0.5) x 10(exp 22)/sq cm and photon index Gamma = 1.0 +/- 0.2, strongly suggestive of magnetospheric emission. For an assumed distance of 10 kpc, the 2-10 keV luminosity of L(sub X) = 6.9 x 10(exp 33) erg/s suggests one of the lowest known X-ray conversion efficiencies L(sub X)/ E = 5.8 x 10(exp -5), similar to that of the Vela pulsar. Finally, the PWN around PSR J2022+3842 revealed by Chandra is also underluminous, with F(sub PWN)/ F(sub PSR) < or approx.1 in the 2-10 keV band, a further surprise given the pulsar's high spin-down luminosity.

  18. EEO Implications of Job Analyses.

    ERIC Educational Resources Information Center

    Lacy, D. Patrick, Jr.

    1979-01-01

    Discusses job analyses as they relate to the requirements of Title VII of the Civil Rights Act of 1964, the Equal Pay Act of 1963, and the Rehabilitation Act of 1973. Argues that job analyses can establish the job-relatedness of entrance requirements and aid in defenses against charges of discrimination. Journal availability: see EA 511 615.

  19. Feed analyses and their interpretation.

    PubMed

    Hall, Mary Beth

    2014-11-01

    Compositional analysis is central to determining the nutritional value of feedstuffs for use in ration formulation. The utility of the values and how they should be used depends on how representative the feed subsample is, the nutritional relevance and analytical variability of the assays, and whether an analysis is suitable to be applied to a particular feedstuff. Commercial analyses presently available for carbohydrates, protein, and fats have improved nutritionally pertinent description of feed fractions. Factors affecting interpretation of feed analyses and the nutritional relevance and application of currently available analyses are discussed.

  20. Neural Spike-Train Analyses of the Speech-Based Envelope Power Spectrum Model

    PubMed Central

    Rallapalli, Varsha H.

    2016-01-01

    Diagnosing and treating hearing impairment is challenging because people with similar degrees of sensorineural hearing loss (SNHL) often have different speech-recognition abilities. The speech-based envelope power spectrum model (sEPSM) has demonstrated that the signal-to-noise ratio (SNRENV) from a modulation filter bank provides a robust speech-intelligibility measure across a wider range of degraded conditions than many long-standing models. In the sEPSM, noise (N) is assumed to: (a) reduce S + N envelope power by filling in dips within clean speech (S) and (b) introduce an envelope noise floor from intrinsic fluctuations in the noise itself. While the promise of SNRENV has been demonstrated for normal-hearing listeners, it has not been thoroughly extended to hearing-impaired listeners because of limited physiological knowledge of how SNHL affects speech-in-noise envelope coding relative to noise alone. Here, envelope coding to speech-in-noise stimuli was quantified from auditory-nerve model spike trains using shuffled correlograms, which were analyzed in the modulation-frequency domain to compute modulation-band estimates of neural SNRENV. Preliminary spike-train analyses show strong similarities to the sEPSM, demonstrating feasibility of neural SNRENV computations. Results suggest that individual differences can occur based on differential degrees of outer- and inner-hair-cell dysfunction in listeners currently diagnosed into the single audiological SNHL category. The predicted acoustic-SNR dependence in individual differences suggests that the SNR-dependent rate of susceptibility could be an important metric in diagnosing individual differences. Future measurements of the neural SNRENV in animal studies with various forms of SNHL will provide valuable insight for understanding individual differences in speech-in-noise intelligibility.

  1. Feed analyses and their interpretation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Compositional analysis is central to determining the nutritional value of feedstuffs. The utility of the values and how they should be used depends on how representative the feed subsample is, the nutritional relevance of the assays, analytical variability of the analyses, and whether a feed is suit...

  2. Mitogenomic analyses of caniform relationships.

    PubMed

    Arnason, Ulfur; Gullberg, Anette; Janke, Axel; Kullberg, Morgan

    2007-12-01

    Extant members of the order Carnivora split into two basal groups, Caniformia (dog-like carnivorans) and Feliformia (cat-like carnivorans). In this study we address phylogenetic relationships within Caniformia applying various methodological approaches to analyses of complete mitochondrial genomes. Pinnipeds are currently well represented with respect to mitogenomic data and here we add seven mt genomes to the non-pinniped caniform collection. The analyses identified a basal caniform divergence between Cynoidea and Arctoidea. Arctoidea split into three primary groups, Ursidae (including the giant panda), Pinnipedia, and a branch, Musteloidea, which encompassed Ailuridae (red panda), Mephitidae (skunks), Procyonidae (raccoons) and Mustelidae (mustelids). The analyses favored a basal arctoid split between Ursidae and a branch containing Pinnipedia and Musteloidea. Within the Musteloidea there was a preference for a basal divergence between Ailuridae and remaining families. Among the latter, the analyses identified a sister group relationship between Mephitidae and a branch that contained Procyonidae and Mustelidae. The mitogenomic distance between the wolf and the dog was shown to be at the same level as that of basal human divergences. The wolf and the dog are commonly considered as separate species in the popular literature. The mitogenomic result is inconsistent with that understanding at the same time as it provides insight into the time of the domestication of the dog relative to basal human mitogenomic divergences.

  3. Introduction to Project Materials Analyses

    ERIC Educational Resources Information Center

    Haley, Frances

    1972-01-01

    The author introduces twenty-six analyses, describes the method of analysis, includes a selection policy for this issue, and lists ten analysts. Each project, analyzed by the combined criteria of the CMAS and the NCSS Guidelines, is examined for background information, product characteristics, rationale and objectives, content, methodology,…

  4. Analysing Children's Drawings: Applied Imagination

    ERIC Educational Resources Information Center

    Bland, Derek

    2012-01-01

    This article centres on a research project in which freehand drawings provided a richly creative and colourful data source of children's imagined, ideal learning environments. Issues concerning the analysis of the visual data are discussed, in particular, how imaginative content was analysed and how the analytical process was dependent on an…

  5. Data Filtering in Instrumental Analyses with Applications to Optical Spectroscopy and Chemical Imaging

    ERIC Educational Resources Information Center

    Vogt, Frank

    2011-01-01

    Most measurement techniques have some limitations imposed by a sensor's signal-to-noise ratio (SNR). Thus, in analytical chemistry, methods for enhancing the SNR are of crucial importance and can be ensured experimentally or established via pre-treatment of digitized data. In many analytical curricula, instrumental techniques are given preference…

  6. Workload analyse of assembling process

    NASA Astrophysics Data System (ADS)

    Ghenghea, L. D.

    2015-11-01

    The workload is the most important indicator for managers responsible of industrial technological processes no matter if these are automated, mechanized or simply manual in each case, machines or workers will be in the focus of workload measurements. The paper deals with workload analyses made to a most part manual assembling technology for roller bearings assembling process, executed in a big company, with integrated bearings manufacturing processes. In this analyses the delay sample technique have been used to identify and divide all bearing assemblers activities, to get information about time parts from 480 minutes day work time that workers allow to each activity. The developed study shows some ways to increase the process productivity without supplementary investments and also indicated the process automation could be the solution to gain maximum productivity.

  7. Mitogenomic analyses of eutherian relationships.

    PubMed

    Arnason, U; Janke, A

    2002-01-01

    Reasonably correct phylogenies are fundamental to the testing of evolutionary hypotheses. Here, we present phylogenetic findings based on analyses of 67 complete mammalian mitochondrial (mt) genomes. The analyses, irrespective of whether they were performed at the amino acid (aa) level or on nucleotides (nt) of first and second codon positions, placed Erinaceomorpha (hedgehogs and their kin) as the sister group of remaining eutherians. Thus, the analyses separated Erinaceomorpha from other traditional lipotyphlans (e.g., tenrecs, moles, and shrews), making traditional Lipotyphla polyphyletic. Both the aa and nt data sets identified the two order-rich eutherian clades, the Cetferungulata (comprising Pholidota, Carnivora, Perissodactyla, Artiodactyla, and Cetacea) and the African clade (Tenrecomorpha, Macroscelidea, Tubulidentata, Hyracoidea, Proboscidea, and Sirenia). The study corroborated recent findings that have identified a sister-group relationship between Anthropoidea and Dermoptera (flying lemurs), thereby making our own order, Primates, a paraphyletic assembly. Molecular estimates using paleontologically well-established calibration points, placed the origin of most eutherian orders in Cretaceous times, 70-100 million years before present (MYBP). The same estimates place all primate divergences much earlier than traditionally believed. For example, the divergence between Homo and Pan is estimated to have taken place approximately 10 MYBP, a dating consistent with recent findings in primate paleontology.

  8. Biological aerosol warner and analyser

    NASA Astrophysics Data System (ADS)

    Schlemmer, Harry; Kürbitz, Gunther; Miethe, Peter; Spieweck, Michael

    2006-05-01

    The development of an integrated sensor device BiSAM (Biological Sampling and Analysing Module) is presented which is designed for rapid detection of aerosol or dust particles potentially loaded with biological warfare agents. All functional steps from aerosol collection via immuno analysis to display of results are fully automated. The core component of the sensor device is an ultra sensitive rapid analyser PBA (Portable Benchtop Analyser) based on a 3 dimensional immuno filtration column of large internal area, Poly HRP marker technology and kinetic optical detection. High sensitivity despite of the short measuring time, high chemical stability of the micro column and robustness against interferents make the PBA an ideal tool for fielded sensor devices. It is especially favourable to combine the PBA with a bio collector because virtually no sample preparation is necessary. Overall, the BiSAM device is capable to detect and identify living micro organisms (bacteria, spores, viruses) as well as toxins in a measuring cycle of typically half an hour duration. In each batch up to 12 different tests can be run in parallel together with positive and negative controls to keep the false alarm rate low.

  9. Magnesium-rich Ejecta in the SNR G284.3-1.8 Around the High-mass Gamma-Ray Binary 1FGL J1018.6-5856

    NASA Astrophysics Data System (ADS)

    Williams, Brian J.; Rangelov, Blagoy; Kargaltsev, Oleg; Pavlov, George G.

    2015-07-01

    We present results from two Chandra observations of the 16.6 day X-ray/γ-ray high-mass binary 1FGL J1018.6-5856 located at the center of the supernova remnant (SNR) G284.3-1.8. The binary spectra, separated by 0.25 in binary phase, are fit with an absorbed power-law model with {{Γ }}≈ 1.7-1.8 for both observations (the flux during the second observation is a factor of 1.7 smaller). In the high-resolution ACIS-I image we found a hint of extended emission ≈ 2\\prime\\prime -3″ southeast of the binary, significant at the 3σ level. Binary evolution codes reproduce the system’s observed properties with two massive stars with an initial 18 day period, undergoing mass transfer and leaving behind a heavy ≈ 2 {M}⊙ neutron star. The initial mass of the progenitor star in this scenario is 27 ± 4 {M}⊙ . Chandra and XMM-Newton images of the remnant show it has a relatively low X-ray surface brightness. The two brightest regions of extended X-ray emission, with luminosities ˜ {10}33 erg s-1 for d = 5 kpc, lie in the northern and western portions and show significantly different spectra. The northern patch is consistent with shocked ISM, with a low temperature and long ionization timescale. However, the western patch is dominated by ejecta, and shows significantly enhanced Mg content relative to other ejecta products. The abundance ratios inferred resemble those from the Large Magellanic Cloud remnant N49B. To our knowledge, this is only the second case of such Mg-rich ejecta found in an SNR. Nucleosynthesis models for core-collapse supernovae predict Mg-rich ejecta from very massive progenitors of \\gt 25 {M}⊙ .

  10. Analysing photonic structures in plants

    PubMed Central

    Vignolini, Silvia; Moyroud, Edwige; Glover, Beverley J.; Steiner, Ullrich

    2013-01-01

    The outer layers of a range of plant tissues, including flower petals, leaves and fruits, exhibit an intriguing variation of microscopic structures. Some of these structures include ordered periodic multilayers and diffraction gratings that give rise to interesting optical appearances. The colour arising from such structures is generally brighter than pigment-based colour. Here, we describe the main types of photonic structures found in plants and discuss the experimental approaches that can be used to analyse them. These experimental approaches allow identification of the physical mechanisms producing structural colours with a high degree of confidence. PMID:23883949

  11. THOR Turbulence Electron Analyser: TEA

    NASA Astrophysics Data System (ADS)

    Fazakerley, Andrew; Moore, Tom; Owen, Chris; Pollock, Craig; Wicks, Rob; Samara, Marilia; Rae, Jonny; Hancock, Barry; Kataria, Dhiren; Rust, Duncan

    2016-04-01

    Turbulence Heating ObserveR (THOR) is the first mission ever flown in space dedicated to plasma turbulence. The Turbulence Electron Analyser (TEA) will measure the plasma electron populations in the mission's Regions of Interest. It will collect a 3D electron velocity distribution with cadences as short as 5 ms. The instrument will be capable of measuring energies up to 30 keV. TEA consists of multiple electrostatic analyser heads arranged so as to measure electrons arriving from look directions covering the full sky, i.e. 4 pi solid angle. The baseline concept is similar to the successful FPI-DES instrument currently operating on the MMS mission. TEA is intended to have a similar angular resolution, but a larger geometric factor. In comparison to earlier missions, TEA improves on the measurement cadence. For example, MMS FPI-DES routinely operates at 30 ms cadence. The objective of measuring distributions at rates as fast as 5 ms is driven by the mission's scientific requirements to resolve electron gyroscale size structures, where plasma heating and fluctuation dissipation is predicted to occur. TEA will therefore be capable of making measurements of the evolution of distribution functions across thin (a few km) current sheets travelling past the spacecraft at up to 600 km/s, of the Power Spectral Density of fluctuations of electron moments and of distributions fast enough to match frequencies with waves expected to be dissipating turbulence (e.g. with 100 Hz whistler waves).

  12. [Network analyses in neuroimaging studies].

    PubMed

    Hirano, Shigeki; Yamada, Makiko

    2013-06-01

    Neurons are anatomically and physiologically connected to each other, and these connections are involved in various neuronal functions. Multiple important neural networks involved in neurodegenerative diseases can be detected using network analyses in functional neuroimaging. First, the basic methods and theories of voxel-based network analyses, such as principal component analysis, independent component analysis, and seed-based analysis, are described. Disease- and symptom-specific brain networks have been identified using glucose metabolism images in patients with Parkinson's disease. These networks enable us to objectively evaluate individual patients and serve as diagnostic tools as well as biomarkers for therapeutic interventions. Many functional MRI studies have shown that "hub" brain regions, such as the posterior cingulate cortex and medial prefrontal cortex, are deactivated by externally driven cognitive tasks; such brain regions form the "default mode network." Recent studies have shown that this default mode network is disrupted from the preclinical phase of Alzheimer's disease and is associated with amyloid deposition in the brain. Some recent studies have shown that the default mode network is also impaired in Parkinson's disease, whereas other studies have shown inconsistent results. These incongruent results could be due to the heterogeneous pharmacological status, differences in mesocortical dopaminergic impairment status, and concomitant amyloid deposition. Future neuroimaging network analysis studies will reveal novel and interesting findings that will uncover the pathomechanisms of neurological and psychiatric disorders. PMID:23735528

  13. Perturbation analyses of intermolecular interactions.

    PubMed

    Koyama, Yohei M; Kobayashi, Tetsuya J; Ueda, Hiroki R

    2011-08-01

    Conformational fluctuations of a protein molecule are important to its function, and it is known that environmental molecules, such as water molecules, ions, and ligand molecules, significantly affect the function by changing the conformational fluctuations. However, it is difficult to systematically understand the role of environmental molecules because intermolecular interactions related to the conformational fluctuations are complicated. To identify important intermolecular interactions with regard to the conformational fluctuations, we develop herein (i) distance-independent and (ii) distance-dependent perturbation analyses of the intermolecular interactions. We show that these perturbation analyses can be realized by performing (i) a principal component analysis using conditional expectations of truncated and shifted intermolecular potential energy terms and (ii) a functional principal component analysis using products of intermolecular forces and conditional cumulative densities. We refer to these analyses as intermolecular perturbation analysis (IPA) and distance-dependent intermolecular perturbation analysis (DIPA), respectively. For comparison of the IPA and the DIPA, we apply them to the alanine dipeptide isomerization in explicit water. Although the first IPA principal components discriminate two states (the α state and PPII (polyproline II) + β states) for larger cutoff length, the separation between the PPII state and the β state is unclear in the second IPA principal components. On the other hand, in the large cutoff value, DIPA eigenvalues converge faster than that for IPA and the top two DIPA principal components clearly identify the three states. By using the DIPA biplot, the contributions of the dipeptide-water interactions to each state are analyzed systematically. Since the DIPA improves the state identification and the convergence rate with retaining distance information, we conclude that the DIPA is a more practical method compared with the

  14. Perturbation analyses of intermolecular interactions

    NASA Astrophysics Data System (ADS)

    Koyama, Yohei M.; Kobayashi, Tetsuya J.; Ueda, Hiroki R.

    2011-08-01

    Conformational fluctuations of a protein molecule are important to its function, and it is known that environmental molecules, such as water molecules, ions, and ligand molecules, significantly affect the function by changing the conformational fluctuations. However, it is difficult to systematically understand the role of environmental molecules because intermolecular interactions related to the conformational fluctuations are complicated. To identify important intermolecular interactions with regard to the conformational fluctuations, we develop herein (i) distance-independent and (ii) distance-dependent perturbation analyses of the intermolecular interactions. We show that these perturbation analyses can be realized by performing (i) a principal component analysis using conditional expectations of truncated and shifted intermolecular potential energy terms and (ii) a functional principal component analysis using products of intermolecular forces and conditional cumulative densities. We refer to these analyses as intermolecular perturbation analysis (IPA) and distance-dependent intermolecular perturbation analysis (DIPA), respectively. For comparison of the IPA and the DIPA, we apply them to the alanine dipeptide isomerization in explicit water. Although the first IPA principal components discriminate two states (the α state and PPII (polyproline II) + β states) for larger cutoff length, the separation between the PPII state and the β state is unclear in the second IPA principal components. On the other hand, in the large cutoff value, DIPA eigenvalues converge faster than that for IPA and the top two DIPA principal components clearly identify the three states. By using the DIPA biplot, the contributions of the dipeptide-water interactions to each state are analyzed systematically. Since the DIPA improves the state identification and the convergence rate with retaining distance information, we conclude that the DIPA is a more practical method compared with the

  15. Uncertainty and Sensitivity Analyses Plan

    SciTech Connect

    Simpson, J.C.; Ramsdell, J.V. Jr.

    1993-04-01

    Hanford Environmental Dose Reconstruction (HEDR) Project staff are developing mathematical models to be used to estimate the radiation dose that individuals may have received as a result of emissions since 1944 from the US Department of Energy's (DOE) Hanford Site near Richland, Washington. An uncertainty and sensitivity analyses plan is essential to understand and interpret the predictions from these mathematical models. This is especially true in the case of the HEDR models where the values of many parameters are unknown. This plan gives a thorough documentation of the uncertainty and hierarchical sensitivity analysis methods recommended for use on all HEDR mathematical models. The documentation includes both technical definitions and examples. In addition, an extensive demonstration of the uncertainty and sensitivity analysis process is provided using actual results from the Hanford Environmental Dose Reconstruction Integrated Codes (HEDRIC). This demonstration shows how the approaches used in the recommended plan can be adapted for all dose predictions in the HEDR Project.

  16. Analyses to improve operational flexibility

    SciTech Connect

    Trikouros, N.G.

    1986-01-01

    Operational flexibility is greatly enhanced if the technical bases for plant limits and design margins are fully understood, and the analyses necessary to evaluate the effect of plant modifications or changes in operating modes on these parameters can be performed as required. If a condition should arise that might jeopardize a plant limit or reduce operational flexibility, it would be necessary to understand the basis for the limit or the specific condition limiting operational flexibility and be capable of performing a reanalysis to either demonstrate that the limit will not be violated or to change the limit. This paper provides examples of GPU Nuclear efforts in this regard. Examples of Oyster Creek and Three Mile Island operating experiences are discussed.

  17. Chemical analyses of provided samples

    NASA Technical Reports Server (NTRS)

    Becker, Christopher H.

    1993-01-01

    Two batches of samples were received and chemical analysis was performed of the surface and near surface regions of the samples by the surface analysis by laser ionization (SALI) method. The samples included four one-inch optics and several paint samples. The analyses emphasized surface contamination or modification. In these studies, pulsed sputtering by 7 keV Ar+ and primarily single-photon ionization (SPI) by coherent 118 nm radiation (at approximately 5 x 10(exp 5) W/cm(sup 2) were used. For two of the samples, also multiphoton ionization (MPI) at 266 nm (approximately 5 x 10(exp 11) W/cm(sup 2) was used. Most notable among the results was the silicone contamination on Mg2 mirror 28-92, and that the Long Duration Exposure Facility (LDEF) paint sample had been enriched in K and Na and depleted in Zn, Si, B, and organic compounds relative to the control paint.

  18. Isotopic signatures by bulk analyses

    SciTech Connect

    Efurd, D.W.; Rokop, D.J.

    1997-12-01

    Los Alamos National Laboratory has developed a series of measurement techniques for identification of nuclear signatures by analyzing bulk samples. Two specific applications for isotopic fingerprinting to identify the origin of anthropogenic radioactivity in bulk samples are presented. The first example is the analyses of environmental samples collected in the US Arctic to determine the impact of dumping of radionuclides in this polar region. Analyses of sediment and biota samples indicate that for the areas sampled the anthropogenic radionuclide content of sediments was predominantly the result of the deposition of global fallout. The anthropogenic radionuclide concentrations in fish, birds and mammals were very low. It can be surmised that marine food chains are presently not significantly affected. The second example is isotopic fingerprinting of water and sediment samples from the Rocky Flats Facility (RFP). The largest source of anthropogenic radioactivity presently affecting surface-waters at RFP is the sediments that are currently residing in the holding ponds. One gram of sediment from a holding pond contains approximately 50 times more plutonium than 1 liter of water from the pond. Essentially 100% of the uranium in Ponds A-1 and A-2 originated as depleted uranium. The largest source of radioactivity in the terminal Ponds A-4, B-5 and C-2 was naturally occurring uranium and its decay product radium. The uranium concentrations in the waters collected from the terminal ponds contained 0.05% or less of the interim standard calculated derived concentration guide for uranium in waters available to the public. All of the radioactivity observed in soil, sediment and water samples collected at RFP was naturally occurring, the result of processes at RFP or the result of global fallout. No extraneous anthropogenic alpha, beta or gamma activities were detected. The plutonium concentrations in Pond C-2 appear to vary seasonally.

  19. Genetic analyses of captive Alala (Corvus hawaiiensis) using AFLP analyses

    USGS Publications Warehouse

    Jarvi, Susan I.; Bianchi, Kiara R.

    2006-01-01

    affected by the mutation rate at microsatellite loci, thus introducing a bias. Also, the number of loci that can be studied is frequently limited to fewer than 10. This theoretically represents a maximum of one marker for each of 10 chromosomes. Dominant markers like AFLP allow a larger fraction of the genome to be screened. Large numbers of loci can be screened by AFLP to resolve very small individual differences that can be used for identification of individuals, estimates of pairwise relatedness and, in some cases, for parentage analyses. Since AFLP is a dominant marker (can not distinguish between +/+ homozygote versus +/- heterozygote), it has limitations for parentage analyses. Only when both parents are homozygous for the absence of alleles (-/-) and offspring show a presence (+/+ or +/-) can the parents be excluded. In this case, microsatellites become preferable as they have the potential to exclude individual parents when the other parent is unknown. Another limitation of AFLP is that the loci are generally less polymorphic (only two alleles/locus) than microsatellite loci (often >10 alleles/locus). While generally fewer than 10 highly polymorphic microsatellite loci are enough to exclude and assign parentage, it might require up to 100 or more AFLP loci. While there are pros and cons to different methodologies, the total number of loci evaluated by AFLP generally offsets the limitations imposed due to the dominant nature of this approach and end results between methods are generally comparable. Overall objectives of this study were to evaluate the level of genetic diversity in the captive population of Alala, to compare genetic data with currently available pedigree information, and to determine the extent of relatedness of mating pairs and among founding individuals.

  20. Imprecise probabilities in engineering analyses

    NASA Astrophysics Data System (ADS)

    Beer, Michael; Ferson, Scott; Kreinovich, Vladik

    2013-05-01

    Probabilistic uncertainty and imprecision in structural parameters and in environmental conditions and loads are challenging phenomena in engineering analyses. They require appropriate mathematical modeling and quantification to obtain realistic results when predicting the behavior and reliability of engineering structures and systems. But the modeling and quantification is complicated by the characteristics of the available information, which involves, for example, sparse data, poor measurements and subjective information. This raises the question whether the available information is sufficient for probabilistic modeling or rather suggests a set-theoretical approach. The framework of imprecise probabilities provides a mathematical basis to deal with these problems which involve both probabilistic and non-probabilistic information. A common feature of the various concepts of imprecise probabilities is the consideration of an entire set of probabilistic models in one analysis. The theoretical differences between the concepts mainly concern the mathematical description of the set of probabilistic models and the connection to the probabilistic models involved. This paper provides an overview on developments which involve imprecise probabilities for the solution of engineering problems. Evidence theory, probability bounds analysis with p-boxes, and fuzzy probabilities are discussed with emphasis on their key features and on their relationships to one another. This paper was especially prepared for this special issue and reflects, in various ways, the thinking and presentation preferences of the authors, who are also the guest editors for this special issue.

  1. Wide area microprobe analyser (WAMPA)

    NASA Astrophysics Data System (ADS)

    Rogoyski, A.; Skidmore, B.; Maheswaran, V.; Wright, I.; Zarnecki, J.; Pillinger, C.

    2006-10-01

    Wide area microprobe analyser (WAMPA) represents a new scientific instrument concept for planetary exploration. WAMPA builds on recently published research such as sensor webs and distributed microsensors [The sensor web: a new instrument concept, SPIE Symposium on Integrated Optics, 20 26 January 2001, San Jose, CA; Design considerations for distributed microsensor systems, Proceedings of the IEEE 1999 Custom Integrated Circuits Conference (CICC ’99), May 1999, pp. 279 286] but adds new sensor and localisation concepts. WAMPA is driven by the recurrent theme in spacecraft and sensor design to achieve smaller, lighter and lower cost systems. The essential characteristics of the WAMPA design that differentiates it from other space science instruments are that WAMPA is both a wide area instrument, consisting of a distributed set of sensors, and that each probe is designed to use little, if any, power. It achieves the former by being utilised in large numbers (>10), requiring that the individual probes be low mass (<100g) and low volume (<10cm). It is envisaged that the probes would be dispersed by landers or rovers as mission support instruments rather than primary science instruments and would be used in hostile environments and rugged terrains where the lander/rover could not be risked (see Fig. 1).

  2. Network analyses in systems pharmacology

    PubMed Central

    Berger, Seth I.; Iyengar, Ravi

    2009-01-01

    Systems pharmacology is an emerging area of pharmacology which utilizes network analysis of drug action as one of its approaches. By considering drug actions and side effects in the context of the regulatory networks within which the drug targets and disease gene products function, network analysis promises to greatly increase our knowledge of the mechanisms underlying the multiple actions of drugs. Systems pharmacology can provide new approaches for drug discovery for complex diseases. The integrated approach used in systems pharmacology can allow for drug action to be considered in the context of the whole genome. Network-based studies are becoming an increasingly important tool in understanding the relationships between drug action and disease susceptibility genes. This review discusses how analysis of biological networks has contributed to the genesis of systems pharmacology and how these studies have improved global understanding of drug targets, suggested new targets and approaches for therapeutics, and provided a deeper understanding of the effects of drugs. Taken together, these types of analyses can lead to new therapeutic options while improving the safety and efficacy of existing medications. Contact: ravi.iyengar@mssm.edu PMID:19648136

  3. Comparison between Inbreeding Analyses Methodologies.

    PubMed

    Esparza, Mireia; Martínez-Abadías, Neus; Sjøvold, Torstein; González-José, Rolando; Hernández, Miquel

    2015-12-01

    Surnames are widely used in inbreeding analysis, but the validity of results has often been questioned due to the failure to comply with the prerequisites of the method. Here we analyze inbreeding in Hallstatt (Austria) between the 17th and the 19th centuries both using genealogies and surnames. The high and significant correlation of the results obtained by both methods demonstrates the validity of the use of surnames in this kind of studies. On the other hand, the inbreeding values obtained (0.24 x 10⁻³ in the genealogies analysis and 2.66 x 10⁻³ in the surnames analysis) are lower than those observed in Europe for this period and for this kind of population, demonstrating the falseness of the apparent isolation of Hallstatt's population. The temporal trend of inbreeding in both analyses does not follow the European general pattern, but shows a maximum in 1850 with a later decrease along the second half of the 19th century. This is probably due to the high migration rate that is implied by the construction of transport infrastructures around the 1870's. PMID:26987150

  4. NOx analyser interefence from alkenes

    NASA Astrophysics Data System (ADS)

    Bloss, W. J.; Alam, M. S.; Lee, J. D.; Vazquez, M.; Munoz, A.; Rodenas, M.

    2012-04-01

    Nitrogen oxides (NO and NO2, collectively NOx) are critical intermediates in atmospheric chemistry. NOx abundance controls the levels of the primary atmospheric oxidants OH, NO3 and O3, and regulates the ozone production which results from the degradation of volatile organic compounds. NOx are also atmospheric pollutants in their own right, and NO2 is commonly included in air quality objectives and regulations. In addition to their role in controlling ozone formation, NOx levels affect the production of other pollutants such as the lachrymator PAN, and the nitrate component of secondary aerosol particles. Consequently, accurate measurement of nitrogen oxides in the atmosphere is of major importance for understanding our atmosphere. The most widely employed approach for the measurement of NOx is chemiluminescent detection of NO2* from the NO + O3 reaction, combined with NO2 reduction by either a heated catalyst or photoconvertor. The reaction between alkenes and ozone is also chemiluminescent; therefore alkenes may contribute to the measured NOx signal, depending upon the instrumental background subtraction cycle employed. This interference has been noted previously, and indeed the effect has been used to measure both alkenes and ozone in the atmosphere. Here we report the results of a systematic investigation of the response of a selection of NOx analysers, ranging from systems used for routine air quality monitoring to atmospheric research instrumentation, to a series of alkenes ranging from ethene to the biogenic monoterpenes, as a function of conditions (co-reactants, humidity). Experiments were performed in the European Photoreactor (EUPHORE) to ensure common calibration, a common sample for the monitors, and to unequivocally confirm the alkene (via FTIR) and NO2 (via DOAS) levels present. The instrument responses ranged from negligible levels up to 10 % depending upon the alkene present and conditions used. Such interferences may be of substantial importance

  5. Ergonomic analyses of downhill skiing.

    PubMed

    Clarys, J P; Publie, J; Zinzen, E

    1994-06-01

    The purpose of this study was to provide electromyographic feedback for (1) pedagogical advice in motor learning, (2) the ergonomics of materials choice and (3) competition. For these purposes: (1) EMG data were collected for the Stem Christie, the Stem Turn and the Parallel Christie (three basic ski initiation drills) and verified for the complexity of patterns; (2) integrated EMG (iEMG) and linear envelopes (LEs) were analysed from standardized positions, motions and slopes using compact, soft and competition skis; (3) in a simulated 'parallel special slalom', the muscular activity pattern and intensity of excavated and flat snow conditions were compared. The EMG data from the three studies were collected on location in the French Alps (Tignes). The analog raw EMG was recorded on the slopes with a portable seven-channel FM recorder (TEAC MR30) and with pre-amplified bipolar surface electrodes supplied with a precision instrumentation amplifier (AD 524, Analog Devices, Norwood, USA). The raw signal was full-wave rectified and enveloped using a moving average principle. This linear envelope was normalized according to the highest peak amplitude procedure per subject and was integrated in order to obtain a reference of muscular intensity. In the three studies and for all subjects (elite skiers: n = 25 in studies 1 and 2, n = 6 in study 3), we found a high level of co-contractions in the lower limb extensors and flexors, especially during the extension phase of the ski movement. The Stem Christie and the Parallel Christie showed higher levels of rhythmic movement (92 and 84%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8064970

  6. ITER Safety Analyses with ISAS

    NASA Astrophysics Data System (ADS)

    Gulden, W.; Nisan, S.; Porfiri, M.-T.; Toumi, I.; de Gramont, T. Boubée

    1997-06-01

    Detailed analyses of accident sequences for the International Thermonuclear Experimental Reactor (ITER), from an initiating event to the environmental release of activity, have involved in the past the use of different types of computer codes in a sequential manner. Since these codes were developed at different time scales in different countries, there is no common computing structure to enable automatic data transfer from one code to the other, and no possibility exists to model or to quantify the effect of coupled physical phenomena. To solve this problem, the Integrated Safety Analysis System of codes (ISAS) is being developed, which allows users to integrate existing computer codes in a coherent manner. This approach is based on the utilization of a command language (GIBIANE) acting as a “glue” to integrate the various codes as modules of a common environment. The present version of ISAS allows comprehensive (coupled) calculations of a chain of codes such as ATHENA (thermal-hydraulic analysis of transients and accidents), INTRA (analysis of in-vessel chemical reactions, pressure built-up, and distribution of reaction products inside the vacuum vessel and adjacent rooms), and NAUA (transport of radiological species within buildings and to the environment). In the near future, the integration of S AFALY (simultaneous analysis of plasma dynamics and thermal behavior of in-vessel components) is also foreseen. The paper briefly describes the essential features of ISAS development and the associated software architecture. It gives first results of a typical ITER accident sequence, a loss of coolant accident (LOCA) in the divertor cooling loop inside the vacuum vessel, amply demonstrating ISAS capabilities.

  7. Analyses of Transistor Punchthrough Failures

    NASA Technical Reports Server (NTRS)

    Nicolas, David P.

    1999-01-01

    The failure of two transistors in the Altitude Switch Assembly for the Solid Rocket Booster followed by two additional failures a year later presented a challenge to failure analysts. These devices had successfully worked for many years on numerous missions. There was no history of failures with this type of device. Extensive checks of the test procedures gave no indication for a source of the cause. The devices were manufactured more than twenty years ago and failure information on this lot date code was not readily available. External visual exam, radiography, PEID, and leak testing were performed with nominal results Electrical testing indicated nearly identical base-emitter and base-collector characteristics (both forward and reverse) with a low resistance short emitter to collector. These characteristics are indicative of a classic failure mechanism called punchthrough. In failure analysis punchthrough refers to an condition where a relatively low voltage pulse causes the device to conduct very hard producing localized areas of thermal runaway or "hot spots". At one or more of these hot spots, the excessive currents melt the silicon. Heavily doped emitter material diffuses through the base region to the collector forming a diffusion pipe shorting the emitter to base to collector. Upon cooling, an alloy junction forms between the pipe and the base region. Generally, the hot spot (punch-through site) is under the bond and no surface artifact is visible. The devices were delidded and the internal structures were examined microscopically. The gold emitter lead was melted on one device, but others had anomalies in the metallization around the in-tact emitter bonds. The SEM examination confirmed some anomalies to be cosmetic defects while other anomalies were artifacts of the punchthrough site. Subsequent to these analyses, the contractor determined that some irregular testing procedures occurred at the time of the failures heretofore unreported. These testing

  8. Pawnee Nation Energy Option Analyses

    SciTech Connect

    Matlock, M.; Kersey, K.; Riding In, C.

    2009-07-21

    Pawnee Nation of Oklahoma Energy Option Analyses In 2003, the Pawnee Nation leadership identified the need for the tribe to comprehensively address its energy issues. During a strategic energy planning workshop a general framework was laid out and the Pawnee Nation Energy Task Force was created to work toward further development of the tribe’s energy vision. The overarching goals of the “first steps” project were to identify the most appropriate focus for its strategic energy initiatives going forward, and to provide information necessary to take the next steps in pursuit of the “best fit” energy options. Description of Activities Performed The research team reviewed existing data pertaining to the availability of biomass (focusing on woody biomass, agricultural biomass/bio-energy crops, and methane capture), solar, wind and hydropower resources on the Pawnee-owned lands. Using these data, combined with assumptions about costs and revenue streams, the research team performed preliminary feasibility assessments for each resource category. The research team also reviewed available funding resources and made recommendations to Pawnee Nation highlighting those resources with the greatest potential for financially-viable development, both in the near-term and over a longer time horizon. Findings and Recommendations Due to a lack of financial incentives for renewable energy, particularly at the state level, combined mediocre renewable energy resources, renewable energy development opportunities are limited for Pawnee Nation. However, near-term potential exists for development of solar hot water at the gym, and an exterior wood-fired boiler system at the tribe’s main administrative building. Pawnee Nation should also explore options for developing LFGTE resources in collaboration with the City of Pawnee. Significant potential may also exist for development of bio-energy resources within the next decade. Pawnee Nation representatives should closely monitor

  9. The complete chemical structure of Saccharomyces cerevisiae rRNA: partial pseudouridylation of U2345 in 25S rRNA by snoRNA snR9

    PubMed Central

    Taoka, Masato; Nobe, Yuko; Yamaki, Yuka; Yamauchi, Yoshio; Ishikawa, Hideaki; Takahashi, Nobuhiro; Nakayama, Hiroshi; Isobe, Toshiaki

    2016-01-01

    We present the complete chemical structures of the rRNAs from the eukaryotic model organism, Saccharomyces cerevisiae. The final structures, as determined with mass spectrometry-based methodology that includes a stable isotope-labelled, non-modified reference RNA, contain 112 sites with 12 different post-transcriptional modifications, including a previously unidentified pseudouridine at position 2345 in 25S rRNA. Quantitative mass spectrometry-based stoichiometric analysis of the different modifications at each site indicated that 94 sites were almost fully modified, whereas the remaining 18 sites were modified to a lesser extent. Superimposed three-dimensional modification maps for S. cerevisiae and Schizosaccharomyces pombe rRNAs confirmed that most of the modified nucleotides are located in functionally important interior regions of the ribosomes. We identified snR9 as the snoRNA responsible for pseudouridylation of U2345 and showed that this pseudouridylation occurs co-transcriptionally and competitively with 2′-O-methylation of U2345. This study ends the uncertainty concerning whether all modified nucleotides in S. cerevisiae rRNAs have been identified and provides a resource for future structural, functional and biogenesis studies of the eukaryotic ribosome. PMID:27325748

  10. 49 CFR 1180.7 - Market analyses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 8 2013-10-01 2013-10-01 false Market analyses. 1180.7 Section 1180.7..., TRACKAGE RIGHTS, AND LEASE PROCEDURES General Acquisition Procedures § 1180.7 Market analyses. (a) For major and significant transactions, applicants shall submit impact analyses (exhibit 12) describing...

  11. 49 CFR 1180.7 - Market analyses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 8 2012-10-01 2012-10-01 false Market analyses. 1180.7 Section 1180.7..., TRACKAGE RIGHTS, AND LEASE PROCEDURES General Acquisition Procedures § 1180.7 Market analyses. (a) For major and significant transactions, applicants shall submit impact analyses (exhibit 12) describing...

  12. Test-Signal Generator For SNR Calibration

    NASA Technical Reports Server (NTRS)

    Gutierrez-Luaces, Benito O.

    1993-01-01

    Assembly of commercial and custom-made electronic equipment designed to generate noisy intermediate-frequency or baseband received phase-modulation data-communication signals with accurately known signal-to-noise ratios. Signals used to perform signal-to-noise-ratio calibrations and other tests of responses of data-communication receivers to noisy incoming signals. Underlying principle applicable to generation of test signals for other advanced data-communication receivers.

  13. Acceleration of cosmic rays in Tycho's SNR.

    NASA Astrophysics Data System (ADS)

    Morlino, G.; Caprioli, D.

    We apply the non-linear diffusive shock acceleration theory in order to describe the properties of SN 1572 (G120.1+1.4, hereafter simply Tycho). By analyzing its multi-wavelength spectrum, we show how Tycho's forward shock (FS) is accelerating protons up to ˜ 500 TeV, channeling into cosmic rays more than 10 per cent of its kinetic energy. We find that the streaming instability induced by cosmic rays is consistent with all the observational evidences indicating a very efficient magnetic field amplification (up to ˜ 300 mu G), in particular the X-ray morphology of the remnant. We are able to explain the gamma-ray spectrum from the GeV up to the TeV band, recently measured respectively by Fermi-LAT and VERITAS, as due to pion decay produced in nuclear collisions by accelerated nuclei scattering against the background gas. We also show that emission due to the accelerated electrons does not play a relevant role in the observed gamma-ray spectrum.

  14. Electron/proton spectrometer certification documentation analyses

    NASA Technical Reports Server (NTRS)

    Gleeson, P.

    1972-01-01

    A compilation of analyses generated during the development of the electron-proton spectrometer for the Skylab program is presented. The data documents the analyses required by the electron-proton spectrometer verification plan. The verification plan was generated to satisfy the ancillary hardware requirements of the Apollo Applications program. The certification of the spectrometer requires that various tests, inspections, and analyses be documented, approved, and accepted by reliability and quality control personnel of the spectrometer development program.

  15. MELCOR analyses for accident progression issues

    SciTech Connect

    Dingman, S.E.; Shaffer, C.J.; Payne, A.C.; Carmel, M.K. )

    1991-01-01

    Results of calculations performed with MELCOR and HECTR in support of the NUREG-1150 study are presented in this report. The analyses examined a wide range of issues. The analyses included integral calculations covering an entire accident sequence, as well as calculations that addressed specific issues that could affect several accident sequences. The results of the analyses for Grand Gulf, Peach Bottom, LaSalle, and Sequoyah are described, and the major conclusions are summarized. 23 refs., 69 figs., 8 tabs.

  16. 49 CFR 1180.7 - Market analyses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., an analysis of traffic flows indicating patterns of geographic competition or product competition... 49 Transportation 8 2011-10-01 2011-10-01 false Market analyses. 1180.7 Section 1180.7..., TRACKAGE RIGHTS, AND LEASE PROCEDURES General Acquisition Procedures § 1180.7 Market analyses. (a)...

  17. Aviation System Analysis Capability Executive Assistant Analyses

    NASA Technical Reports Server (NTRS)

    Roberts, Eileen; Kostiuk, Peter

    1999-01-01

    This document describes the analyses that may be incorporated into the Aviation System Analysis Capability Executive Assistant. The document will be used as a discussion tool to enable NASA and other integrated aviation system entities to evaluate, discuss, and prioritize analyses.

  18. 10 CFR 436.24 - Uncertainty analyses.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Procedures for Life Cycle Cost Analyses § 436.24 Uncertainty analyses. If particular items of cost data or... impact of uncertainty on the calculation of life cycle cost effectiveness or the assignment of rank order... and probabilistic analysis. If additional analysis casts substantial doubt on the life cycle...

  19. 10 CFR 436.24 - Uncertainty analyses.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Procedures for Life Cycle Cost Analyses § 436.24 Uncertainty analyses. If particular items of cost data or... impact of uncertainty on the calculation of life cycle cost effectiveness or the assignment of rank order... and probabilistic analysis. If additional analysis casts substantial doubt on the life cycle...

  20. 10 CFR 436.24 - Uncertainty analyses.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Procedures for Life Cycle Cost Analyses § 436.24 Uncertainty analyses. If particular items of cost data or... impact of uncertainty on the calculation of life cycle cost effectiveness or the assignment of rank order... and probabilistic analysis. If additional analysis casts substantial doubt on the life cycle...

  1. Operator-free flow injection analyser

    PubMed Central

    de Faria, Lourival C.

    1991-01-01

    A flow injection analyser has been constructed to allow an operator-free determination of up to 40 samples. Besides the usual FIA apparatus, the analyser includes a home-made sample introduction device made with three electromechanical three-way valves and an auto-sampler from Technicon which has been adapted to be commanded by an external digital signal. The analyser is controlled by a single board SDK-8085 microcomputer. The necessary interface to couple the analyser components to the microcomputer is also described. The analyser was evaluated for a Cr(VI)-FIA determination showing a very good performance with a relative standard deviation for 15 signals from the injection of 100 μl of a 1.0 mg.ml-1 standard Cr(VI) solution being equal to 0.5%. PMID:18924899

  2. Functional analyses and treatment of precursor behavior.

    PubMed

    Najdowski, Adel C; Wallace, Michele D; Ellsworth, Carrie L; MacAleese, Alicia N; Cleveland, Jackie M

    2008-01-01

    Functional analysis has been demonstrated to be an effective method to identify environmental variables that maintain problem behavior. However, there are cases when conducting functional analyses of severe problem behavior may be contraindicated. The current study applied functional analysis procedures to a class of behavior that preceded severe problem behavior (precursor behavior) and evaluated treatments based on the outcomes of the functional analyses of precursor behavior. Responding for all participants was differentiated during the functional analyses, and individualized treatments eliminated precursor behavior. These results suggest that functional analysis of precursor behavior may offer an alternative, indirect method to assess the operant function of severe problem behavior. PMID:18468282

  3. Functional Analyses and Treatment of Precursor Behavior

    PubMed Central

    Najdowski, Adel C; Wallace, Michele D; Ellsworth, Carrie L; MacAleese, Alicia N; Cleveland, Jackie M

    2008-01-01

    Functional analysis has been demonstrated to be an effective method to identify environmental variables that maintain problem behavior. However, there are cases when conducting functional analyses of severe problem behavior may be contraindicated. The current study applied functional analysis procedures to a class of behavior that preceded severe problem behavior (precursor behavior) and evaluated treatments based on the outcomes of the functional analyses of precursor behavior. Responding for all participants was differentiated during the functional analyses, and individualized treatments eliminated precursor behavior. These results suggest that functional analysis of precursor behavior may offer an alternative, indirect method to assess the operant function of severe problem behavior. PMID:18468282

  4. SCM Forcing Data Derived from NWP Analyses

    DOE Data Explorer

    Jakob, Christian

    2008-01-15

    Forcing data, suitable for use with single column models (SCMs) and cloud resolving models (CRMs), have been derived from NWP analyses for the ARM (Atmospheric Radiation Measurement) Tropical Western Pacific (TWP) sites of Manus Island and Nauru.

  5. 49 CFR 1180.7 - Market analyses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... OF TRANSPORTATION RULES OF PRACTICE RAILROAD ACQUISITION, CONTROL, MERGER, CONSOLIDATION PROJECT, TRACKAGE RIGHTS, AND LEASE PROCEDURES General Acquisition Procedures § 1180.7 Market analyses. (a) For... company's marketing plan and existing and potential competitive alternatives (inter- as well as...

  6. Quality control considerations in performing washability analyses

    SciTech Connect

    Graham, R.D.

    1984-10-01

    The author describes, in considerable detail, the procedures for carrying out washability analyses as laid down in ASTM Standard Test Method D4371. These include sampling, sample preparation, hydrometer standardisation, washability testing, and analysis of specific gravity fractions.

  7. 10 CFR 436.24 - Uncertainty analyses.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methodology and... by conducting additional analyses using any standard engineering economics method such as sensitivity... energy or water system alternative....

  8. 10 CFR 436.24 - Uncertainty analyses.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methodology and... by conducting additional analyses using any standard engineering economics method such as sensitivity... energy or water system alternative....

  9. Anthocyanin analyses of Vaccinium fruit dietary supplements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vaccinium fruit ingredients within dietary supplements were identified by comparisons with anthocyanin analyses of known Vaccinium profiles (demonstration of anthocyanin fingerprinting). Available Vaccinium supplements were purchased and analyzed; their anthocyanin profiles (based on HPLC separation...

  10. Comparison with Russian analyses of meteor impact

    SciTech Connect

    Canavan, G.H.

    1997-06-01

    The inversion model for meteor impacts is used to discuss Russian analyses and compare principal results. For common input parameters, the models produce consistent estimates of impactor parameters. Directions for future research are discussed and prioritized.

  11. Analyses and forecasts with LAWS winds

    NASA Technical Reports Server (NTRS)

    Wang, Muyin; Paegle, Jan

    1994-01-01

    Horizontal fluxes of atmospheric water vapor are studied for summer months during 1989 and 1992 over North and South America based on analyses from European Center for Medium Range Weather Forecasts, US National Meteorological Center, and United Kingdom Meteorological Office. The calculations are performed over 20 deg by 20 deg box-shaped midlatitude domains located to the east of the Rocky Mountains in North America, and to the east of the Andes Mountains in South America. The fluxes are determined from operational center gridded analyses of wind and moisture. Differences in the monthly mean moisture flux divergence determined from these analyses are as large as 7 cm/month precipitable water equivalent over South America, and 3 cm/month over North America. Gridded analyses at higher spatial and temporal resolution exhibit better agreement in the moisture budget study. However, significant discrepancies of the moisture flux divergence computed from different gridded analyses still exist. The conclusion is more pessimistic than Rasmusson's estimate based on station data. Further analysis reveals that the most significant sources of error result from model surface elevation fields, gaps in the data archive, and uncertainties in the wind and specific humidity analyses. Uncertainties in the wind analyses are the most important problem. The low-level jets, in particular, are substantially different in the different data archives. Part of the reason for this may be due to the way the different analysis models parameterized physical processes affecting low-level jets. The results support the inference that the noise/signal ratio of the moisture budget may be improved more rapidly by providing better wind observations and analyses than by providing better moisture data.

  12. A History of Rotorcraft Comprehensive Analyses

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne

    2013-01-01

    A history of the development of rotorcraft comprehensive analyses is presented. Comprehensive analyses are digital computer programs that calculate the aeromechanical behavior of the rotor and aircraft, bringing together the most advanced models of the geometry, structure, dynamics, and aerodynamics available in rotary wing technology. The development of the major codes of the last five decades from industry, government, and universities is described. A number of common themes observed in this history are discussed.

  13. Finite element analyses of CCAT preliminary design

    NASA Astrophysics Data System (ADS)

    Sarawit, Andrew T.; Kan, Frank W.

    2014-07-01

    This paper describes the development of the CCAT telescope finite element model (FEM) and the analyses performed to support the preliminary design work. CCAT will be a 25 m diameter telescope operating in the 0.2 to 2 mm wavelength range. It will be located at an elevation of 5600 m on Cerro Chajnantor in Northern Chile, near ALMA. The telescope will be equipped with wide-field cameras and spectrometers mounted at the two Nasmyth foci. The telescope will be inside an enclosure to protect it from wind buffeting, direct solar heating, and bad weather. The main structures of the telescope include a steel Mount and a carbon-fiber-reinforced-plastic (CFRP) primary truss. The finite element model developed in this study was used to perform modal, frequency response, seismic response spectrum, stress, and deflection analyses of telescope. Modal analyses of telescope were performed to compute the structure natural frequencies and mode shapes and to obtain reduced order modal output at selected locations in the telescope structure to support the design of the Mount control system. Modal frequency response analyses were also performed to compute transfer functions at these selected locations. Seismic response spectrum analyses of the telescope subject to the Maximum Likely Earthquake were performed to compute peak accelerations and seismic demand stresses. Stress analyses were performed for gravity load to obtain gravity demand stresses. Deflection analyses for gravity load, thermal load, and differential elevation drive torque were performed so that the CCAT Observatory can verify that the structures meet the stringent telescope surface and pointing error requirements.

  14. Prismatic analyser concept for neutron spectrometers

    SciTech Connect

    Birk, Jonas O.; Jacobsen, Johan; Hansen, Rasmus L.; Lefmann, Kim; Markó, Márton; Niedermayer, Christof; Freeman, Paul G.; Christensen, Niels B.; Månsson, Martin; Rønnow, Henrik M.

    2014-11-15

    Developments in modern neutron spectroscopy have led to typical sample sizes decreasing from few cm to several mm in diameter samples. We demonstrate how small samples together with the right choice of analyser and detector components makes distance collimation an important concept in crystal analyser spectrometers. We further show that this opens new possibilities where neutrons with different energies are reflected by the same analyser but counted in different detectors, thus improving both energy resolution and total count rate compared to conventional spectrometers. The technique can readily be combined with advanced focussing geometries and with multiplexing instrument designs. We present a combination of simulations and data showing three different energies simultaneously reflected from one analyser. Experiments were performed on a cold triple axis instrument and on a prototype inverse geometry Time-of-flight spectrometer installed at PSI, Switzerland, and shows excellent agreement with the predictions. Typical improvements will be 2.0 times finer resolution and a factor of 1.9 in flux gain compared to a focussing Rowland geometry, or of 3.3 times finer resolution and a factor of 2.4 in flux gain compared to a single flat analyser slab.

  15. Meta-analyses of randomized controlled trials.

    PubMed

    Sacks, H S; Berrier, J; Reitman, D; Ancona-Berk, V A; Chalmers, T C

    1987-02-19

    A new type of research, termed meta-analysis, attempts to analyze and combine the results of previous reports. We found 86 meta-analyses of reports of randomized controlled trials in the English-language literature. We evaluated the quality of these meta-analyses, using a scoring method that considered 23 items in six major areas--study design, combinability, control of bias, statistical analysis, sensitivity analysis, and application of results. Only 24 meta-analyses (28 percent) addressed all six areas, 31 (36 percent) addressed five, 25 (29 percent) addressed four, 5 (6 percent) addressed three, and 1 (1 percent) addressed two. Of the 23 individual items, between 1 and 14 were addressed satisfactorily (mean +/- SD, 7.7 +/- 2.7). We conclude that an urgent need exists for improved methods in literature searching, quality evaluation of trials, and synthesizing of the results.

  16. Geomagnetic local and regional harmonic analyses.

    USGS Publications Warehouse

    Alldredge, L.R.

    1982-01-01

    Procedures are developed for using rectangular and cylindrical harmonic analyses in local and regional areas. Both the linear least squares analysis, applicable when component data are available, and the nonlinear least squares analysis, applicable when only total field data are available, are treated. When component data are available, it is advantageous to work with residual fields obtained by subtracting components derived from a harmonic potential from the observed components. When only total field intensity data are available, they must be used directly. Residual values cannot be used. Cylindrical harmonic analyses are indicated when fields tend toward cylindrical symmetry; otherwise, rectangular harmonic analyses will be more advantageous. Examples illustrating each type of analysis are given.-Author

  17. A qualitative method for analysing multivoicedness

    PubMed Central

    Aveling, Emma-Louise; Gillespie, Alex; Cornish, Flora

    2015-01-01

    ‘Multivoicedness’ and the ‘multivoiced Self’ have become important theoretical concepts guiding research. Drawing on the tradition of dialogism, the Self is conceptualised as being constituted by a multiplicity of dynamic, interacting voices. Despite the growth in literature and empirical research, there remains a paucity of established methodological tools for analysing the multivoiced Self using qualitative data. In this article, we set out a systematic, practical ‘how-to’ guide for analysing multivoicedness. Using theoretically derived tools, our three-step method comprises: identifying the voices of I-positions within the Self’s talk (or text), identifying the voices of ‘inner-Others’, and examining the dialogue and relationships between the different voices. We elaborate each step and illustrate our method using examples from a published paper in which data were analysed using this method. We conclude by offering more general principles for the use of the method and discussing potential applications. PMID:26664292

  18. Advanced toroidal facility vaccuum vessel stress analyses

    SciTech Connect

    Hammonds, C.J.; Mayhall, J.A.

    1987-01-01

    The complex geometry of the Advance Toroidal Facility (ATF) vacuum vessel required special analysis techniques in investigating the structural behavior of the design. The response of a large-scale finite element model was found for transportation and operational loading. Several computer codes and systems, including the National Magnetic Fusion Energy Computer Center Cray machines, were implemented in accomplishing these analyses. The work combined complex methods that taxed the limits of both the codes and the computer systems involved. Using MSC/NASTRAN cyclic-symmetry solutions permitted using only 1/12 of the vessel geometry to mathematically analyze the entire vessel. This allowed the greater detail and accuracy demanded by the complex geometry of the vessel. Critical buckling-pressure analyses were performed with the same model. The development, results, and problems encountered in performing these analyses are described. 5 refs., 3 figs.

  19. Advanced laser stratospheric monitoring systems analyses

    NASA Technical Reports Server (NTRS)

    Larsen, J. C.

    1984-01-01

    This report describes the software support supplied by Systems and Applied Sciences Corporation for the study of Advanced Laser Stratospheric Monitoring Systems Analyses under contract No. NAS1-15806. This report discusses improvements to the Langley spectroscopic data base, development of LHS instrument control software and data analyses and validation software. The effect of diurnal variations on the retrieved concentrations of NO, NO2 and C L O from a space and balloon borne measurement platform are discussed along with the selection of optimum IF channels for sensing stratospheric species from space.

  20. Identifying, analysing and solving problems in practice.

    PubMed

    Hewitt-Taylor, Jaqui

    When a problem is identified in practice, it is important to clarify exactly what it is and establish the cause before seeking a solution. This solution-seeking process should include input from those directly involved in the problematic situation, to enable individuals to contribute their perspective, appreciate why any change in practice is necessary and what will be achieved by the change. This article describes some approaches to identifying and analysing problems in practice so that effective solutions can be devised. It includes a case study and examples of how the Five Whys analysis, fishbone diagram, problem tree analysis, and Seven-S Model can be used to analyse a problem.

  1. Uncertainty quantification approaches for advanced reactor analyses.

    SciTech Connect

    Briggs, L. L.; Nuclear Engineering Division

    2009-03-24

    The original approach to nuclear reactor design or safety analyses was to make very conservative modeling assumptions so as to ensure meeting the required safety margins. Traditional regulation, as established by the U. S. Nuclear Regulatory Commission required conservatisms which have subsequently been shown to be excessive. The commission has therefore moved away from excessively conservative evaluations and has determined best-estimate calculations to be an acceptable alternative to conservative models, provided the best-estimate results are accompanied by an uncertainty evaluation which can demonstrate that, when a set of analysis cases which statistically account for uncertainties of all types are generated, there is a 95% probability that at least 95% of the cases meet the safety margins. To date, nearly all published work addressing uncertainty evaluations of nuclear power plant calculations has focused on light water reactors and on large-break loss-of-coolant accident (LBLOCA) analyses. However, there is nothing in the uncertainty evaluation methodologies that is limited to a specific type of reactor or to specific types of plant scenarios. These same methodologies can be equally well applied to analyses for high-temperature gas-cooled reactors and to liquid metal reactors, and they can be applied to steady-state calculations, operational transients, or severe accident scenarios. This report reviews and compares both statistical and deterministic uncertainty evaluation approaches. Recommendations are given for selection of an uncertainty methodology and for considerations to be factored into the process of evaluating uncertainties for advanced reactor best-estimate analyses.

  2. FAME: Software for analysing rock microstructures

    NASA Astrophysics Data System (ADS)

    Hammes, Daniel M.; Peternell, Mark

    2016-05-01

    Determination of rock microstructures leads to a better understanding of the formation and deformation of polycrystalline solids. Here, we present FAME (Fabric Analyser based Microstructure Evaluation), an easy-to-use MATLAB®-based software for processing datasets recorded by an automated fabric analyser microscope. FAME is provided as a MATLAB®-independent Windows® executable with an intuitive graphical user interface. Raw data from the fabric analyser microscope can be automatically loaded, filtered and cropped before analysis. Accurate and efficient rock microstructure analysis is based on an advanced user-controlled grain labelling algorithm. The preview and testing environments simplify the determination of appropriate analysis parameters. Various statistic and plotting tools allow a graphical visualisation of the results such as grain size, shape, c-axis orientation and misorientation. The FAME2elle algorithm exports fabric analyser data to an elle (modelling software)-supported format. FAME supports batch processing for multiple thin section analysis or large datasets that are generated for example during 2D in-situ deformation experiments. The use and versatility of FAME is demonstrated on quartz and deuterium ice samples.

  3. Chemical Analyses of Silicon Aerogel Samples

    SciTech Connect

    van der Werf, I.; Palmisano, F.; De Leo, Raffaele; Marrone, Stefano

    2008-04-01

    After five years of operating, two Aerogel counters: A1 and A2, taking data in Hall A at Jefferson Lab, suffered a loss of performance. In this note possible causes of degradation have been studied. In particular, various chemical and physical analyses have been carried out on several Aerogel tiles and on adhesive tape in order to reveal the presence of contaminants.

  4. Amino acid analyses of Apollo 14 samples.

    NASA Technical Reports Server (NTRS)

    Gehrke, C. W.; Zumwalt, R. W.; Kuo, K.; Aue, W. A.; Stalling, D. L.; Kvenvolden, K. A.; Ponnamperuma, C.

    1972-01-01

    Detection limits were between 300 pg and 1 ng for different amino acids, in an analysis by gas-liquid chromatography of water extracts from Apollo 14 lunar fines in which amino acids were converted to their N-trifluoro-acetyl-n-butyl esters. Initial analyses of water and HCl extracts of sample 14240 and 14298 samples showed no amino acids above background levels.

  5. Multiphase Method for Analysing Online Discussions

    ERIC Educational Resources Information Center

    Häkkinen, P.

    2013-01-01

    Several studies have analysed and assessed online performance and discourse using quantitative and qualitative methods. Quantitative measures have typically included the analysis of participation rates and learning outcomes in terms of grades. Qualitative measures of postings, discussions and context features aim to give insights into the nature…

  6. Correlation Functions Aid Analyses Of Spectra

    NASA Technical Reports Server (NTRS)

    Beer, Reinhard; Norton, Robert H., Jr.

    1989-01-01

    New uses found for correlation functions in analyses of spectra. In approach combining elements of both pattern-recognition and traditional spectral-analysis techniques, spectral lines identified in data appear useless at first glance because they are dominated by noise. New approach particularly useful in measurement of concentrations of rare species of molecules in atmosphere.

  7. 49 CFR 1180.7 - Market analyses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... identify and address relevant markets and issues, and provide additional information as requested by the...). (b) For major transactions, applicants shall submit “full system” impact analyses (incorporating any... (including inter- and intramodal competition, product competition, and geographic competition) and...

  8. Cosmetology: Task Analyses. Competency-Based Education.

    ERIC Educational Resources Information Center

    Henrico County Public Schools, Glen Allen, VA. Virginia Vocational Curriculum Center.

    These task analyses are designed to be used in combination with the "Trade and Industrial Education Service Area Resource" in order to implement competency-based education in the cosmetology program in Virginia. The task analysis document contains the task inventory, suggested task sequence lists, and content outlines for the secondary courses…

  9. What's missing from avian global diversification analyses?

    PubMed

    Reddy, Sushma

    2014-08-01

    The accumulation of vast numbers of molecular phylogenetic studies has contributed to huge knowledge gains in the evolutionary history of birds. This permits subsequent analyses of avian diversity, such as how and why diversification varies across the globe and among taxonomic groups. However, available genetic data for these meta-analyses are unevenly distributed across different geographic regions and taxonomic groups. To comprehend the impact of this variation on the interpretation of global diversity patterns, I examined the availability of genetic data for possible biases in geographic and taxonomic sampling of birds. I identified three main disparities of sampling that are geographically associated with latitude (temperate, tropical), hemispheres (East, West), and range size. Tropical regions, which host the vast majority of species, are substantially less studied. Moreover, Eastern regions, such as the Old World Tropics and Australasia, stand out as being disproportionately undersampled, with up to half of communities not being represented in recent studies. In terms of taxonomic discrepancies, a majority of genetically undersampled clades are exclusively found in tropical regions. My analysis identifies several disparities in the key regions of interest of global diversity analyses. Differential sampling can have considerable impacts on these global comparisons and call into question recent interpretations of latitudinal or hemispheric differences of diversification rates. Moreover, this review pinpoints understudied regions whose biota are in critical need of modern systematic analyses.

  10. The Economic Cost of Homosexuality: Multilevel Analyses

    ERIC Educational Resources Information Center

    Baumle, Amanda K.; Poston, Dudley, Jr.

    2011-01-01

    This article builds on earlier studies that have examined "the economic cost of homosexuality," by using data from the 2000 U.S. Census and by employing multilevel analyses. Our findings indicate that partnered gay men experience a 12.5 percent earnings penalty compared to married heterosexual men, and a statistically insignificant earnings…

  11. Functional Analyses and Treatment of Precursor Behavior

    ERIC Educational Resources Information Center

    Najdowski, Adel C.; Wallace, Michele D.; Ellsworth, Carrie L.; MacAleese, Alicia N.; Cleveland, Jackie

    2008-01-01

    Functional analysis has been demonstrated to be an effective method to identify environmental variables that maintain problem behavior. However, there are cases when conducting functional analyses of severe problem behavior may be contraindicated. The current study applied functional analysis procedures to a class of behavior that preceded severe…

  12. Using Solo to Analyse Group Responses

    ERIC Educational Resources Information Center

    Reading, Chris; Lawrie, Christine

    2004-01-01

    The increased use of group work in teaching and learning has seen an increased need for knowledge about assessment of group work. This report considers exploratory research where the SOLO Taxonomy, previously used to analyse the quality of individual responses, is applied to group responses. The responses were created as part of an activity…

  13. Analysing Simple Electric Motors in the Classroom

    ERIC Educational Resources Information Center

    Yap, Jeff; MacIsaac, Dan

    2006-01-01

    Electromagnetic phenomena and devices such as motors are typically unfamiliar to both teachers and students. To better visualize and illustrate the abstract concepts (such as magnetic fields) underlying electricity and magnetism, we suggest that students construct and analyse the operation of a simply constructed Johnson electric motor. In this…

  14. Impact analyses after pipe rupture. [PWR; BWR

    SciTech Connect

    Chun, R.C.; Chuang, T.Y.

    1983-12-13

    Two of the French pipe whip experiments are reproduced with the computer code WIPS. The WIPS results are in good agreement with the experimental data and the French computer code TEDEL. This justifies the use of its pipe element in conjunction with its U-bar element in a simplified method of impact analyses.

  15. Analysing organic transistors based on interface approximation

    SciTech Connect

    Akiyama, Yuto; Mori, Takehiko

    2014-01-15

    Temperature-dependent characteristics of organic transistors are analysed thoroughly using interface approximation. In contrast to amorphous silicon transistors, it is characteristic of organic transistors that the accumulation layer is concentrated on the first monolayer, and it is appropriate to consider interface charge rather than band bending. On the basis of this model, observed characteristics of hexamethylenetetrathiafulvalene (HMTTF) and dibenzotetrathiafulvalene (DBTTF) transistors with various surface treatments are analysed, and the trap distribution is extracted. In turn, starting from a simple exponential distribution, we can reproduce the temperature-dependent transistor characteristics as well as the gate voltage dependence of the activation energy, so we can investigate various aspects of organic transistors self-consistently under the interface approximation. Small deviation from such an ideal transistor operation is discussed assuming the presence of an energetically discrete trap level, which leads to a hump in the transfer characteristics. The contact resistance is estimated by measuring the transfer characteristics up to the linear region.

  16. Neuronal network analyses: premises, promises and uncertainties

    PubMed Central

    Parker, David

    2010-01-01

    Neuronal networks assemble the cellular components needed for sensory, motor and cognitive functions. Any rational intervention in the nervous system will thus require an understanding of network function. Obtaining this understanding is widely considered to be one of the major tasks facing neuroscience today. Network analyses have been performed for some years in relatively simple systems. In addition to the direct insights these systems have provided, they also illustrate some of the difficulties of understanding network function. Nevertheless, in more complex systems (including human), claims are made that the cellular bases of behaviour are, or will shortly be, understood. While the discussion is necessarily limited, this issue will examine these claims and highlight some traditional and novel aspects of network analyses and their difficulties. This introduction discusses the criteria that need to be satisfied for network understanding, and how they relate to traditional and novel approaches being applied to addressing network function. PMID:20603354

  17. Reliability of chemical analyses of water samples

    SciTech Connect

    Beardon, R.

    1989-11-01

    Ground-water quality investigations require reliable chemical analyses of water samples. Unfortunately, laboratory analytical results are often unreliable. The Uranium Mill Tailings Remedial Action (UMTRA) Project`s solution to this problem was to establish a two phase quality assurance program for the analysis of water samples. In the first phase, eight laboratories analyzed three solutions of known composition. The analytical accuracy of each laboratory was ranked and three laboratories were awarded contracts. The second phase consists of on-going monitoring of the reliability of the selected laboratories. The following conclusions are based on two years experience with the UMTRA Project`s Quality Assurance Program. The reliability of laboratory analyses should not be taken for granted. Analytical reliability may be independent of the prices charged by laboratories. Quality assurance programs benefit both the customer and the laboratory.

  18. Identifying, analysing and solving problems in practice.

    PubMed

    Hewitt-Taylor, Jaqui

    When a problem is identified in practice, it is important to clarify exactly what it is and establish the cause before seeking a solution. This solution-seeking process should include input from those directly involved in the problematic situation, to enable individuals to contribute their perspective, appreciate why any change in practice is necessary and what will be achieved by the change. This article describes some approaches to identifying and analysing problems in practice so that effective solutions can be devised. It includes a case study and examples of how the Five Whys analysis, fishbone diagram, problem tree analysis, and Seven-S Model can be used to analyse a problem. PMID:22848969

  19. Sensitivity in risk analyses with uncertain numbers.

    SciTech Connect

    Tucker, W. Troy; Ferson, Scott

    2006-06-01

    Sensitivity analysis is a study of how changes in the inputs to a model influence the results of the model. Many techniques have recently been proposed for use when the model is probabilistic. This report considers the related problem of sensitivity analysis when the model includes uncertain numbers that can involve both aleatory and epistemic uncertainty and the method of calculation is Dempster-Shafer evidence theory or probability bounds analysis. Some traditional methods for sensitivity analysis generalize directly for use with uncertain numbers, but, in some respects, sensitivity analysis for these analyses differs from traditional deterministic or probabilistic sensitivity analyses. A case study of a dike reliability assessment illustrates several methods of sensitivity analysis, including traditional probabilistic assessment, local derivatives, and a ''pinching'' strategy that hypothetically reduces the epistemic uncertainty or aleatory uncertainty, or both, in an input variable to estimate the reduction of uncertainty in the outputs. The prospects for applying the methods to black box models are also considered.

  20. Analyses and characterization of double shell tank

    SciTech Connect

    Not Available

    1994-10-04

    Evaporator candidate feed from tank 241-AP-108 (108-AP) was sampled under prescribed protocol. Physical, inorganic, and radiochemical analyses were performed on tank 108-AP. Characterization of evaporator feed tank waste is needed primarily for an evaluation of its suitability to be safely processed through the evaporator. Such analyses should provide sufficient information regarding the waste composition to confidently determine whether constituent concentrations are within not only safe operating limits, but should also be relevant to functional limits for operation of the evaporator. Characterization of tank constituent concentrations should provide data which enable a prediction of where the types and amounts of environmentally hazardous waste are likely to occur in the evaporator product streams.

  1. [Clinical research=design*measurements*statistical analyses].

    PubMed

    Furukawa, Toshiaki

    2012-06-01

    A clinical study must address true endpoints that matter for the patients and the doctors. A good clinical study starts with a good clinical question. Formulating a clinical question in the form of PECO can sharpen one's original question. In order to perform a good clinical study one must have a knowledge of study design, measurements and statistical analyses: The first is taught by epidemiology, the second by psychometrics and the third by biostatistics.

  2. Inelastic and Dynamic Fracture and Stress Analyses

    NASA Technical Reports Server (NTRS)

    Atluri, S. N.

    1984-01-01

    Large deformation inelastic stress analysis and inelastic and dynamic crack propagation research work is summarized. The salient topics of interest in engine structure analysis that are discussed herein include: (1) a path-independent integral (T) in inelastic fracture mechanics, (2) analysis of dynamic crack propagation, (3) generalization of constitutive relations of inelasticity for finite deformations , (4) complementary energy approaches in inelastic analyses, and (5) objectivity of time integration schemes in inelastic stress analysis.

  3. Evaluation of the Technicon Axon analyser.

    PubMed

    Martínez, C; Márquez, M; Cortés, M; Mercé, J; Rodriguez, J; González, F

    1990-01-01

    An evaluation of the Technicon Axon analyser was carried out following the guidelines of the 'Sociedad Española de Química Clínica' and the European Committee for Clinical Laboratory Standards.A photometric study revealed acceptable results at both 340 nm and 404 nm. Inaccuracy and imprecision were lower at 404 nm than at 340 nm, although poor dispersion was found at both wavelengths, even at low absorbances. Drift was negligible, the imprecision of the sample pipette delivery system was greater for small sample volumes, the reagent pipette delivery system imprecision was acceptable and the sample diluting system study showed good precision and accuracy.Twelve analytes were studied for evaluation of the analyser under routine working conditions. Satisfactory results were obtained for within-run imprecision, while coefficients of variation for betweenrun imprecision were much greater than expected. Neither specimenrelated nor specimen-independent contamination was found in the carry-over study. For all analytes assayed, when comparing patient sample results with those obtained in a Hitachi 737 analyser, acceptable relative inaccuracy was observed.

  4. Department of Energy's team's analyses of Soviet designed VVERs

    SciTech Connect

    Not Available

    1989-09-01

    This document provides Appendices A thru K of this report. The topics discussed respectively are: radiation induced embrittlement and annealing of reactor pressure vessel steels; loss of coolant accident blowdown analyses; LOCA blowdown response analyses; non-seismic structural response analyses; seismic analyses; S'' seal integrity; reactor transient analyses; fire protection; aircraft impacts; and boric acid induced corrosion. (FI).

  5. Evaluation of Model Operational Analyses during DYNAMO

    NASA Astrophysics Data System (ADS)

    Ciesielski, Paul; Johnson, Richard

    2013-04-01

    A primary component of the observing system in the DYNAMO-CINDY2011-AMIE field campaign was an atmospheric sounding network comprised of two sounding quadrilaterals, one north and one south of the equator over the central Indian Ocean. During the experiment a major effort was undertaken to ensure the real-time transmission of these data onto the GTS (Global Telecommunication System) for dissemination to the operational centers (ECMWF, NCEP, JMA, etc.). Preliminary estimates indicate that ~95% of the soundings from the enhanced sounding network were successfully transmitted and potentially used in their data assimilation systems. Because of the wide use of operational and reanalysis products (e.g., in process studies, initializing numerical simulations, construction of large-scale forcing datasets for CRMs, etc.), their validity will be examined by comparing a variety of basic and diagnosed fields from two operational analyses (ECMWF and NCEP) to similar analyses based solely on sounding observations. Particular attention will be given to the vertical structures of apparent heating (Q1) and drying (Q2) from the operational analyses (OA), which are strongly influenced by cumulus parameterizations, a source of model infidelity. Preliminary results indicate that the OA products did a reasonable job at capturing the mean and temporal characteristics of convection during the DYNAMO enhanced observing period, which included the passage of two significant MJO events during the October-November 2011 period. For example, temporal correlations between Q2-budget derived rainfall from the OA products and that estimated from the TRMM satellite (i.e., the 3B42V7 product) were greater than 0.9 over the Northern Sounding Array of DYNAMO. However closer inspection of the budget profiles show notable differences between the OA products and the sounding-derived results in low-level (surface to 700 hPa) heating and drying structures. This presentation will examine these differences and

  6. Combustion Devices CFD Team Analyses Review

    NASA Technical Reports Server (NTRS)

    Rocker, Marvin

    2008-01-01

    A variety of CFD simulations performed by the Combustion Devices CFD Team at Marshall Space Flight Center will be presented. These analyses were performed to support Space Shuttle operations and Ares-1 Crew Launch Vehicle design. Results from the analyses will be shown along with pertinent information on the CFD codes and computational resources used to obtain the results. Six analyses will be presented - two related to the Space Shuttle and four related to the Ares I-1 launch vehicle now under development at NASA. First, a CFD analysis of the flow fields around the Space Shuttle during the first six seconds of flight and potential debris trajectories within those flow fields will be discussed. Second, the combusting flows within the Space Shuttle Main Engine's main combustion chamber will be shown. For the Ares I-1, an analysis of the performance of the roll control thrusters during flight will be described. Several studies are discussed related to the J2-X engine to be used on the upper stage of the Ares I-1 vehicle. A parametric study of the propellant flow sequences and mixture ratios within the GOX/GH2 spark igniters on the J2-X is discussed. Transient simulations will be described that predict the asymmetric pressure loads that occur on the rocket nozzle during the engine start as the nozzle fills with combusting gases. Simulations of issues that affect temperature uniformity within the gas generator used to drive the J-2X turbines will described as well, both upstream of the chamber in the injector manifolds and within the combustion chamber itself.

  7. Stable isotopic analyses in paleoclimatic reconstruction

    SciTech Connect

    Wigand, P.E.

    1995-09-01

    Most traditional paleoclimatic proxy data have inherent time lags between climatic input and system response that constrain their use in accurate reconstruction of paleoclimate chronology, scaling of its variability, and the elucidation of the processes that determine its impact on the biotic and abiotic environment. With the exception of dendroclimatology, and studies of short-lived organisms and pollen recovered from annually varved lacustrine sediments, significant periods of time ranging from years, to centuries, to millennia may intervene between climate change and its first manifestation in paleoclimatic proxy data records. Reconstruction of past climate through changes in plant community composition derived from pollen sequences and plant remains from ancient woodrat middens, wet environments and dry caves all suffer from these lags. However, stable isotopic analyses can provide more immediate indication of biotic response to climate change. Evidence of past physiological response of organisms to changes in effective precipitation as climate varies can be provided by analyses of the stable isotopic content of plant macrofossils from various contexts. These analyses consider variation in the stable isotopic (hydrogen, oxygen and carbon) content of plant tissues as it reflects (1) past global or local temperature through changes in meteoric (rainfall) water chemistry in the case of the first two isotopes, and (2) plant stress through changes in plant respiration/transpiration processes under differing water availability, and varying atmospheric CO, composition (which itself may actually be a net result of biotic response to climate change). Studies currently being conducted in the Intermountain West indicate both long- and short-term responses that when calibrated with modem analogue studies have the potential of revealing not only the timing of climate events, but their direction, magnitude and rapidity.

  8. Method of performing computational aeroelastic analyses

    NASA Technical Reports Server (NTRS)

    Silva, Walter A. (Inventor)

    2011-01-01

    Computational aeroelastic analyses typically use a mathematical model for the structural modes of a flexible structure and a nonlinear aerodynamic model that can generate a plurality of unsteady aerodynamic responses based on the structural modes for conditions defining an aerodynamic condition of the flexible structure. In the present invention, a linear state-space model is generated using a single execution of the nonlinear aerodynamic model for all of the structural modes where a family of orthogonal functions is used as the inputs. Then, static and dynamic aeroelastic solutions are generated using computational interaction between the mathematical model and the linear state-space model for a plurality of periodic points in time.

  9. Analyses of Shuttle Orbiter approach and landing

    NASA Technical Reports Server (NTRS)

    Ashkenas, I. L.; Hoh, R. H.; Teper, G. L.

    1982-01-01

    A study of the Shuttle Orbiter approach and landing conditions is summarized. The causes of observed PIO-like flight deficiencies are listed, and possible corrective measures are examined. Closed-loop pilot/vehicle analyses are described, and a description is given of path-attitude stability boundaries. The latter novel approach is found to be of great value in delineating and illustrating the basic causes of this multiloop pilot control problem. It is shown that the analytical results are consistent with flight test and fixed-base simulation. Conclusions are drawn concerning possible improvements in the Shuttle Orbiter/Digital Flight Control System.

  10. Further analyses of Rio Cuarto impact glass

    NASA Technical Reports Server (NTRS)

    Schultz, Peter H.; Bunch, T. E.; Koeberl, C.; Collins, W.

    1993-01-01

    Initial analyses of the geologic setting, petrology, and geochemistry of glasses recovered from within and around the elongate Rio Cuarto (RC) craters in Argentina focused on selected samples in order to document the general similarity with impactites around other terrestrial impact craters and to establish their origin. Continued analysis has surveyed the diversity in compositions for a range of samples, examined further evidence for temperature and pressure history, and compared the results with experimentally fused loess from oblique hypervelocity impacts. These new results not only firmly establish their impact origin but provide new insight on the impact process.

  11. Environmental monitoring final report: groundwater chemical analyses

    SciTech Connect

    Not Available

    1984-02-01

    This report presents the results of analyses of groundwater qualtiy at the SRC-I Demonstration Plant site in Newman, Kentucky. Samples were obtained from a network of 23 groundwater observation wells installed during previous studies. The groundwater was well within US EPA Interim Primary Drinking Water Standards for trace metals, radioactivity, and pesticides, but exceeded the standard for coliform bacteria. Several US EPA Secondary Drinking Water Standards were exceeded, namely, manganese, color, iron, and total dissolved solids. Based on the results, Dames and Moore recommend that all wells should be sterilized and those wells built in 1980 should be redeveloped. 1 figure, 6 tables.

  12. Analyses of containment structures with corrosion damage

    SciTech Connect

    Cherry, J.L.

    1996-12-31

    Corrosion damage to a nuclear power plant containment structure can degrade the pressure capacity of the vessel. For the low-carbon, low- strength steels used in containments, the effect of corrosion on material properties is discussed. Strain-to-failure tests, in uniaxial tension, have been performed on corroded material samples. Results were used to select strain-based failure criteria for corroded steel. Using the ABAQUS finite element analysis code, the capacity of a typical PWR Ice Condenser containment with corrosion damage has been studied. Multiple analyses were performed with the locations of the corrosion the containment, and the amount of corrosion varied in each analysis.

  13. Special analyses reveal coke-deposit structure

    SciTech Connect

    Albright, L.F.

    1988-08-01

    A scanning electron microscope (SEM) and an energy dispersive X-ray analyzer (EDAX) have been used to obtain information that clarifies the three mechanisms of coke formation in ethylene furnaces, and to analyze the metal condition at the exit of furnace. The results can be used to examine furnace operations and develop improved ethylene plant practices. In this first of four articles on the analyses of coke and metal samples, the coking mechanisms and coke deposits in a section of tube from an actual ethylene furnace (Furnace A) from a plant on the Texas Gulf Coast are discussed. The second articles in the series will analyze the condition of the tube metal in the same furnace. To show how coke deposition and metal condition dependent on the operating parameters of an ethylene furnace, the third article in the series will show the coke deposition in a Texas Gulf Coast furnace tube (Furnace B) that operated at shorter residence time. The fourth article discusses the metal condition in that furnace. Some recommendations, based on the analyses and findings, are offered in the fourth article that could help extend the life of ethylene furnace tubes, and also improve overall ethylene plant operations.

  14. Autisme et douleur – analyse bibliographique

    PubMed Central

    Dubois, Amandine; Rattaz, Cécile; Pry, René; Baghdadli, Amaria

    2010-01-01

    La présente analyse bibliographique a pour objectif de réaliser un bilan des travaux publiés dans le champ de la douleur et de l’autisme. L’article aborde, dans un premier temps, les études publiées concernant les modes d’expression de la douleur observés dans cette population. Différentes hypothèses permettant d’expliquer les particularités expressives des personnes avec autisme sont ensuite passées en revue : excès d’endorphines, particularités dans le traitement sensoriel, déficit sociocommunicatif. Cette analyse bibliographique aborde, pour terminer, la question de l’évaluation et de la prise en compte de la douleur chez les personnes avec autisme. Les auteurs concluent à l’absence d’homogénéité des résultats des études publiées et au besoin de poursuivre les recherches afin de parvenir à des données consensuelles sur un domaine d’étude encore peu exploité au plan scientifique. Sur un plan clinique, l’approfondissement des connaissances dans ce domaine devrait permettre de mettre au point des outils d’évaluation de la douleur et d’ainsi en assurer une meilleure prise en charge au quotidien. PMID:20808970

  15. Repeatability of published microarray gene expression analyses.

    PubMed

    Ioannidis, John P A; Allison, David B; Ball, Catherine A; Coulibaly, Issa; Cui, Xiangqin; Culhane, Aedín C; Falchi, Mario; Furlanello, Cesare; Game, Laurence; Jurman, Giuseppe; Mangion, Jon; Mehta, Tapan; Nitzberg, Michael; Page, Grier P; Petretto, Enrico; van Noort, Vera

    2009-02-01

    Given the complexity of microarray-based gene expression studies, guidelines encourage transparent design and public data availability. Several journals require public data deposition and several public databases exist. However, not all data are publicly available, and even when available, it is unknown whether the published results are reproducible by independent scientists. Here we evaluated the replication of data analyses in 18 articles on microarray-based gene expression profiling published in Nature Genetics in 2005-2006. One table or figure from each article was independently evaluated by two teams of analysts. We reproduced two analyses in principle and six partially or with some discrepancies; ten could not be reproduced. The main reason for failure to reproduce was data unavailability, and discrepancies were mostly due to incomplete data annotation or specification of data processing and analysis. Repeatability of published microarray studies is apparently limited. More strict publication rules enforcing public data availability and explicit description of data processing and analysis should be considered.

  16. Analyses of containment structures with corrosion damage

    SciTech Connect

    Cherry, J.L.

    1997-01-01

    Corrosion damage that has been found in a number of nuclear power plant containment structures can degrade the pressure capacity of the vessel. This has prompted concerns regarding the capacity of corroded containments to withstand accident loadings. To address these concerns, finite element analyses have been performed for a typical PWR Ice Condenser containment structure. Using ABAQUS, the pressure capacity was calculated for a typical vessel with no corrosion damage. Multiple analyses were then performed with the location of the corrosion and the amount of corrosion varied in each analysis. Using a strain-based failure criterion, a {open_quotes}lower bound{close_quotes}, {open_quotes}best estimate{close_quotes}, and {open_quotes}upper bound{close_quotes} failure level was predicted for each case. These limits were established by: determining the amount of variability that exists in material properties of typical containments, estimating the amount of uncertainty associated with the level of modeling detail and modeling assumptions, and estimating the effect of corrosion on the material properties.

  17. Used Fuel Management System Interface Analyses - 13578

    SciTech Connect

    Howard, Robert; Busch, Ingrid; Nutt, Mark; Morris, Edgar; Puig, Francesc; Carter, Joe; Delley, Alexcia; Rodwell, Phillip; Hardin, Ernest; Kalinina, Elena; Clark, Robert; Cotton, Thomas

    2013-07-01

    Preliminary system-level analyses of the interfaces between at-reactor used fuel management, consolidated storage facilities, and disposal facilities, along with the development of supporting logistics simulation tools, have been initiated to provide the U.S. Department of Energy (DOE) and other stakeholders with information regarding the various alternatives for managing used nuclear fuel (UNF) generated by the current fleet of light water reactors operating in the United States. An important UNF management system interface consideration is the need for ultimate disposal of UNF assemblies contained in waste packages that are sized to be compatible with different geologic media. Thermal analyses indicate that waste package sizes for the geologic media under consideration by the Used Fuel Disposition Campaign may be significantly smaller than the canisters being used for on-site dry storage by the nuclear utilities. Therefore, at some point along the UNF disposition pathway, there could be a need to repackage fuel assemblies already loaded and being loaded into the dry storage canisters currently in use. The implications of where and when the packaging or repackaging of commercial UNF will occur are key questions being addressed in this evaluation. The analysis demonstrated that thermal considerations will have a major impact on the operation of the system and that acceptance priority, rates, and facility start dates have significant system implications. (authors)

  18. Bioinformatics tools for analysing viral genomic data.

    PubMed

    Orton, R J; Gu, Q; Hughes, J; Maabar, M; Modha, S; Vattipally, S B; Wilkie, G S; Davison, A J

    2016-04-01

    The field of viral genomics and bioinformatics is experiencing a strong resurgence due to high-throughput sequencing (HTS) technology, which enables the rapid and cost-effective sequencing and subsequent assembly of large numbers of viral genomes. In addition, the unprecedented power of HTS technologies has enabled the analysis of intra-host viral diversity and quasispecies dynamics in relation to important biological questions on viral transmission, vaccine resistance and host jumping. HTS also enables the rapid identification of both known and potentially new viruses from field and clinical samples, thus adding new tools to the fields of viral discovery and metagenomics. Bioinformatics has been central to the rise of HTS applications because new algorithms and software tools are continually needed to process and analyse the large, complex datasets generated in this rapidly evolving area. In this paper, the authors give a brief overview of the main bioinformatics tools available for viral genomic research, with a particular emphasis on HTS technologies and their main applications. They summarise the major steps in various HTS analyses, starting with quality control of raw reads and encompassing activities ranging from consensus and de novo genome assembly to variant calling and metagenomics, as well as RNA sequencing.

  19. Transportation systems analyses: Volume 1: Executive Summary

    NASA Astrophysics Data System (ADS)

    1993-05-01

    The principal objective of this study is to accomplish a systems engineering assessment of the nation's space transportation infrastructure. This analysis addresses the necessary elements to perform man delivery and return, cargo transfer, cargo delivery, payload servicing, and the exploration of the Moon and Mars. Specific elements analyzed, but not limited to, include the Space Exploration Initiative (SEI), the National Launch System (NLS), the current expendable launch vehicle (ELV) fleet, ground facilities, the Space Station Freedom (SSF), and other civil, military and commercial payloads. The performance of this study entails maintaining a broad perspective on the large number of transportation elements that could potentially comprise the U.S. space infrastructure over the next several decades. To perform this systems evaluation, top-level trade studies are conducted to enhance our understanding of the relationships between elements of the infrastructure. This broad 'infrastructure-level perspective' permits the identification of preferred infrastructures. Sensitivity analyses are performed to assure the credibility and usefulness of study results. This executive summary of the transportation systems analyses (TSM) semi-annual report addresses the SSF logistics resupply. Our analysis parallels the ongoing NASA SSF redesign effort. Therefore, there could be no SSF design to drive our logistics analysis. Consequently, the analysis attempted to bound the reasonable SSF design possibilities (and the subsequent transportation implications). No other strategy really exists until after a final decision is rendered on the SSF configuration.

  20. Hierarchical regression for analyses of multiple outcomes.

    PubMed

    Richardson, David B; Hamra, Ghassan B; MacLehose, Richard F; Cole, Stephen R; Chu, Haitao

    2015-09-01

    In cohort mortality studies, there often is interest in associations between an exposure of primary interest and mortality due to a range of different causes. A standard approach to such analyses involves fitting a separate regression model for each type of outcome. However, the statistical precision of some estimated associations may be poor because of sparse data. In this paper, we describe a hierarchical regression model for estimation of parameters describing outcome-specific relative rate functions and associated credible intervals. The proposed model uses background stratification to provide flexible control for the outcome-specific associations of potential confounders, and it employs a hierarchical "shrinkage" approach to stabilize estimates of an exposure's associations with mortality due to different causes of death. The approach is illustrated in analyses of cancer mortality in 2 cohorts: a cohort of dioxin-exposed US chemical workers and a cohort of radiation-exposed Japanese atomic bomb survivors. Compared with standard regression estimates of associations, hierarchical regression yielded estimates with improved precision that tended to have less extreme values. The hierarchical regression approach also allowed the fitting of models with effect-measure modification. The proposed hierarchical approach can yield estimates of association that are more precise than conventional estimates when one wishes to estimate associations with multiple outcomes. PMID:26232395

  1. Waste Stream Analyses for Nuclear Fuel Cycles

    SciTech Connect

    N. R. Soelberg

    2010-08-01

    A high-level study was performed in Fiscal Year 2009 for the U.S. Department of Energy (DOE) Office of Nuclear Energy (NE) Advanced Fuel Cycle Initiative (AFCI) to provide information for a range of nuclear fuel cycle options (Wigeland 2009). At that time, some fuel cycle options could not be adequately evaluated since they were not well defined and lacked sufficient information. As a result, five families of these fuel cycle options are being studied during Fiscal Year 2010 by the Systems Analysis Campaign for the DOE NE Fuel Cycle Research and Development (FCRD) program. The quality and completeness of data available to date for the fuel cycle options is insufficient to perform quantitative radioactive waste analyses using recommended metrics. This study has been limited thus far to qualitative analyses of waste streams from the candidate fuel cycle options, because quantitative data for wastes from the front end, fuel fabrication, reactor core structure, and used fuel for these options is generally not yet available.

  2. Computational analyses of multilevel discourse comprehension.

    PubMed

    Graesser, Arthur C; McNamara, Danielle S

    2011-04-01

    The proposed multilevel framework of discourse comprehension includes the surface code, the textbase, the situation model, the genre and rhetorical structure, and the pragmatic communication level. We describe these five levels when comprehension succeeds and also when there are communication misalignments and comprehension breakdowns. A computer tool has been developed, called Coh-Metrix, that scales discourse (oral or print) on dozens of measures associated with the first four discourse levels. The measurement of these levels with an automated tool helps researchers track and better understand multilevel discourse comprehension. Two sets of analyses illustrate the utility of Coh-Metrix in discourse theory and educational practice. First, Coh-Metrix was used to measure the cohesion of the text base and situation model, as well as potential extraneous variables, in a sample of published studies that manipulated text cohesion. This analysis helped us better understand what was precisely manipulated in these studies and the implications for discourse comprehension mechanisms. Second, Coh-Metrix analyses are reported for samples of narrative and science texts in order to advance the argument that traditional text difficulty measures are limited because they fail to accommodate most of the levels of the multilevel discourse comprehension framework.

  3. ISFSI site boundary radiation dose rate analyses.

    PubMed

    Hagler, R J; Fero, A H

    2005-01-01

    Across the globe nuclear utilities are in the process of designing and analysing Independent Spent Fuel Storage Installations (ISFSI) for the purpose of above ground spent-fuel storage primarily to mitigate the filling of spent-fuel pools. Using a conjoining of discrete ordinates transport theory (DORT) and Monte Carlo (MCNP) techniques, an ISFSI was analysed to determine neutron and photon dose rates for a generic overpack, and ISFSI pad configuration and design at distances ranging from 1 to -1700 m from the ISFSI array. The calculated dose rates are used to address the requirements of 10CFR72.104, which provides limits to be enforced for the protection of the public by the NRC in regard to ISFSI facilities. For this overpack, dose rates decrease by three orders of magnitude through the first 200 m moving away from the ISFSI. In addition, the contributions from different source terms changes over distance. It can be observed that although side photons provide the majority of dose rate in this calculation, scattered photons and side neutrons take on more importance as the distance from the ISFSI is increased. PMID:16604670

  4. Chapter 9: Analyses Using Disease Ontologies

    PubMed Central

    Shah, Nigam H.; Cole, Tyler; Musen, Mark A.

    2012-01-01

    Advanced statistical methods used to analyze high-throughput data such as gene-expression assays result in long lists of “significant genes.” One way to gain insight into the significance of altered expression levels is to determine whether Gene Ontology (GO) terms associated with a particular biological process, molecular function, or cellular component are over- or under-represented in the set of genes deemed significant. This process, referred to as enrichment analysis, profiles a gene-set, and is widely used to makes sense of the results of high-throughput experiments. The canonical example of enrichment analysis is when the output dataset is a list of genes differentially expressed in some condition. To determine the biological relevance of a lengthy gene list, the usual solution is to perform enrichment analysis with the GO. We can aggregate the annotating GO concepts for each gene in this list, and arrive at a profile of the biological processes or mechanisms affected by the condition under study. While GO has been the principal target for enrichment analysis, the methods of enrichment analysis are generalizable. We can conduct the same sort of profiling along other ontologies of interest. Just as scientists can ask “Which biological process is over-represented in my set of interesting genes or proteins?” we can also ask “Which disease (or class of diseases) is over-represented in my set of interesting genes or proteins?“. For example, by annotating known protein mutations with disease terms from the ontologies in BioPortal, Mort et al. recently identified a class of diseases—blood coagulation disorders—that were associated with a 14-fold depletion in substitutions at O-linked glycosylation sites. With the availability of tools for automatic annotation of datasets with terms from disease ontologies, there is no reason to restrict enrichment analyses to the GO. In this chapter, we will discuss methods to perform enrichment analysis using any

  5. Phylogenomic Analyses Support Traditional Relationships within Cnidaria.

    PubMed

    Zapata, Felipe; Goetz, Freya E; Smith, Stephen A; Howison, Mark; Siebert, Stefan; Church, Samuel H; Sanders, Steven M; Ames, Cheryl Lewis; McFadden, Catherine S; France, Scott C; Daly, Marymegan; Collins, Allen G; Haddock, Steven H D; Dunn, Casey W; Cartwright, Paulyn

    2015-01-01

    Cnidaria, the sister group to Bilateria, is a highly diverse group of animals in terms of morphology, lifecycles, ecology, and development. How this diversity originated and evolved is not well understood because phylogenetic relationships among major cnidarian lineages are unclear, and recent studies present contrasting phylogenetic hypotheses. Here, we use transcriptome data from 15 newly-sequenced species in combination with 26 publicly available genomes and transcriptomes to assess phylogenetic relationships among major cnidarian lineages. Phylogenetic analyses using different partition schemes and models of molecular evolution, as well as topology tests for alternative phylogenetic relationships, support the monophyly of Medusozoa, Anthozoa, Octocorallia, Hydrozoa, and a clade consisting of Staurozoa, Cubozoa, and Scyphozoa. Support for the monophyly of Hexacorallia is weak due to the equivocal position of Ceriantharia. Taken together, these results further resolve deep cnidarian relationships, largely support traditional phylogenetic views on relationships, and provide a historical framework for studying the evolutionary processes involved in one of the most ancient animal radiations.

  6. Project analysis and integration economic analyses summary

    NASA Technical Reports Server (NTRS)

    Macomber, H. L.

    1986-01-01

    An economic-analysis summary was presented for the manufacture of crystalline-silicon modules involving silicon ingot/sheet, growth, slicing, cell manufacture, and module assembly. Economic analyses provided: useful quantitative aspects for complex decision-making to the Flat-plate Solar Array (FSA) Project; yardsticks for design and performance to industry; and demonstration of how to evaluate and understand the worth of research and development both to JPL and other government agencies and programs. It was concluded that future research and development funds for photovoltaics must be provided by the Federal Government because the solar industry today does not reap enough profits from its present-day sales of photovoltaic equipment.

  7. Precise Chemical Analyses of Planetary Surfaces

    NASA Technical Reports Server (NTRS)

    Kring, David; Schweitzer, Jeffrey; Meyer, Charles; Trombka, Jacob; Freund, Friedemann; Economou, Thanasis; Yen, Albert; Kim, Soon Sam; Treiman, Allan H.; Blake, David; Lisse, Carey

    1996-01-01

    We identify the chemical elements and element ratios that should be analyzed to address many of the issues identified by the Committee on Planetary and Lunar Exploration (COMPLEX). We determined that most of these issues require two sensitive instruments to analyze the necessary complement of elements. In addition, it is useful in many cases to use one instrument to analyze the outermost planetary surface (e.g. to determine weathering effects), while a second is used to analyze a subsurface volume of material (e.g., to determine the composition of unaltered planetary surface material). This dual approach to chemical analyses will also facilitate the calibration of orbital and/or Earth-based spectral observations of the planetary body. We determined that in many cases the scientific issues defined by COMPLEX can only be fully addressed with combined packages of instruments that would supplement the chemical data with mineralogic or visual information.

  8. Comparative Analyses of Plant Transcription Factor Databases

    PubMed Central

    Ramirez, Silvia R; Basu, Chhandak

    2009-01-01

    Transcription factors (TFs) are proteinaceous complex, which bind to the promoter regions in the DNA and affect transcription initiation. Plant TFs control gene expressions and genes control many physiological processes, which in turn trigger cascades of biochemical reactions in plant cells. The databases available for plant TFs are somewhat abundant but all convey different information and in different formats. Some of the publicly available plant TF databases may be narrow, while others are broad in scopes. For example, some of the best TF databases are ones that are very specific with just one plant species, but there are also other databases that contain a total of up to 20 different plant species. In this review plant TF databases ranging from a single species to many will be assessed and described. The comparative analyses of all the databases and their advantages and disadvantages are also discussed. PMID:19721806

  9. Anthocyanin analyses of Vaccinium fruit dietary supplements.

    PubMed

    Lee, Jungmin

    2016-09-01

    Vaccinium fruit ingredients within dietary supplements were identified by comparisons with anthocyanin analyses of known Vaccinium profiles (demonstration of anthocyanin fingerprinting). Available Vaccinium supplements were purchased and analyzed, their anthocyanin profiles (based on high-performance liquid chromatography [HPLC] separation) indicated if products' fruit origin listings were authentic. Over 30% of the Vaccinium fruit (cranberry, lingonberry, bilberry, and blueberry; 14 of 45) products available as dietary supplements did not contain the fruit listed as ingredients. Six supplements contained no anthocyanins. Five others had contents differing from labeled fruit (e.g., bilberry capsules containing Andean blueberry fruit). Of the samples that did contain the specified fruit (n = 27), anthocyanin content ranged from 0.04 to 14.37 mg per capsule, tablet, or teaspoon (5 g). Approaches to utilizing anthocyanins in assessment of sample authenticity, and a discussion of the challenges with anthocyanin profiles in quality control are both presented. PMID:27625778

  10. Gravitationswellen - ein neues Fenster zum Universum

    NASA Astrophysics Data System (ADS)

    Aufmuth, Peter; Rüdiger, Albrecht

    2000-01-01

    Die von der Allgemeinen Relativitätstheorie vorhergesagten Gravitationswellen sind bisher noch nicht direkt beobachtet worden. In Europa, Japan und den USA hat man mit dem Bau von großen Laserinterferometern begonnen, die dies ermöglichen sollen. Damit eröffnet sich die Aussicht, bisher verschlossene Bereiche des Weltalls durch Gravitationswellenastronomie zu studieren.

  11. Zum Stand der Rechnungen am Halleyschen Kometen

    NASA Astrophysics Data System (ADS)

    Landgraf, Werner

    1984-02-01

    Einzelheiten zur Bahnbestimmung des Halleyschen Kometen. U.a. angegeben sind verbesserte Bahnelemente aus 90 Beob. und Normalorten 1607 Sept 28 - 1983 Feb 13 unter Auflösung nach sekular veränderlichen nichtgravitativen Kräften nach einem Modell von Rickmann - Froeschlé mittlerer thermischer Trägheit

  12. Analyse de formes par moiré

    NASA Astrophysics Data System (ADS)

    Harthong, J.; Sahli, H.; Poinsignon, R.; Meyrueis, P.

    1991-01-01

    We present a mathematical analysis of moiré phenomena for shape recognition. The basic theoretical concept - and tool - will be the contour function. We show that the mathematical analysis is greatly simplified by the systematic recourse to this tool. The analysis presented permits a simultaneous treatment of two different modes of implementing the moiré technique : the direct mode (widely used and well-known), and the converse mode (scarcely used). The converse mode consists in computing and designing a grating especially for one model of object, in such a manner that if (and only if) the object is in conformity with the prescribed model, the resulting moiré fringes are parallel straight lines. We give explicit formulas and algorithms for such computations. Nous présentons une analyse mathématique du moiré permettant une reconnaissance des formes. Le concept théorique de base est celui de “ fonction de contour ”. Nous montrons que l'analyse mathématique est simplifiée en faisant appel à ces fonctions. De plus, la méthode proposée permet de traiter d'une manière unifiée les deux différents modes d'utilisation des techniques de moiré : le mode direct (le plus utilisé et le mieux connu), et le moiré inverse, qui consiste, pour un modèle d'objet donné, à calculer et réaliser un réseau spécifique, tel que si (et seulement si) un objet est conforme au modèle, les franges de moiré obtenues seront des lignes droites parallèles. Nous proposons des formules explicites et des algorithmes pour ces traitements.

  13. Statistical analyses of the relative risk.

    PubMed Central

    Gart, J J

    1979-01-01

    Let P1 be the probability of a disease in one population and P2 be the probability of a disease in a second population. The ratio of these quantities, R = P1/P2, is termed the relative risk. We consider first the analyses of the relative risk from retrospective studies. The relation between the relative risk and the odds ratio (or cross-product ratio) is developed. The odds ratio can be considered a parameter of an exponential model possessing sufficient statistics. This permits the development of exact significance tests and confidence intervals in the conditional space. Unconditional tests and intervals are also considered briefly. The consequences of misclassification errors and ignoring matching or stratifying are also considered. The various methods are extended to combination of results over the strata. Examples of case-control studies testing the association between HL-A frequencies and cancer illustrate the techniques. The parallel analyses of prospective studies are given. If P1 and P2 are small with large samples sizes the appropriate model is a Poisson distribution. This yields a exponential model with sufficient statistics. Exact conditional tests and confidence intervals can then be developed. Here we consider the case where two populations are compared adjusting for sex differences as well as for the strata (or covariate) differences such as age. The methods are applied to two examples: (1) testing in the two sexes the ratio of relative risks of skin cancer in people living in different latitudes, and (2) testing over time the ratio of the relative risks of cancer in two cities, one of which fluoridated its drinking water and one which did not. PMID:540589

  14. Reporting guidelines for population pharmacokinetic analyses.

    PubMed

    Dykstra, Kevin; Mehrotra, Nitin; Tornøe, Christoffer Wenzel; Kastrissios, Helen; Patel, Bela; Al-Huniti, Nidal; Jadhav, Pravin; Wang, Yaning; Byon, Wonkyung

    2015-06-01

    The purpose of this work was to develop a consolidated set of guiding principles for reporting of population pharmacokinetic (PK) analyses based on input from a survey of practitioners as well as discussions between industry, consulting and regulatory scientists. The survey found that identification of population covariate effects on drug exposure and support for dose selection (where population PK frequently serves as preparatory analysis to exposure-response modeling) are the main areas of influence for population PK analysis. The proposed guidelines consider two main purposes of population PK reports (1) to present key analysis findings and their impact on drug development decisions, and (2) as documentation of the analysis methods for the dual purpose of enabling review of the analysis and facilitating future use of the models. This work also identified two main audiences for the reports: (1) a technically competent group responsible for in-depth review of the data, methodology, and results, and (2) a scientifically literate, but not technically adept group, whose main interest is in the implications of the analysis for the broader drug development program. We recommend a generalized question-based approach with six questions that need to be addressed throughout the report. We recommend eight sections (Synopsis, Introduction, Data, Methods, Results, Discussion, Conclusions, Appendix) with suggestions for the target audience and level of detail for each section. A section providing general expectations regarding population PK reporting from a regulatory perspective is also included. We consider this an important step towards industrialization of the field of pharmacometrics such that non-technical audience also understands the role of pharmacometrics analyses in decision making. Population PK reports were chosen as representative reports to derive these recommendations; however, the guiding principles presented here are applicable for all pharmacometric reports

  15. Reporting guidelines for population pharmacokinetic analyses.

    PubMed

    Dykstra, Kevin; Mehrotra, Nitin; Tornøe, Christoffer Wenzel; Kastrissios, Helen; Patel, Bela; Al-Huniti, Nidal; Jadhav, Pravin; Wang, Yaning; Byon, Wonkyung

    2015-08-01

    The purpose of this work was to develop a consolidated set of guiding principles for the reporting of population pharmacokinetic (PK) analyses based on input from a survey of practitioners as well as discussions between industry, consulting, and regulatory scientists. The survey found that identification of population covariate effects on drug exposure and support for dose selection (in which population PK frequently serves as preparatory analysis for exposure-response modeling) are the main areas of influence for population PK analysis. The proposed guidelines consider 2 main purposes of population PK reports: (1) to present key analysis findings and their impact on drug development decisions, and (2) as documentation of the analysis methods for the dual purpose of enabling review of the analysis and facilitating future use of the models. This work also identified 2 main audiences for the reports: (1) a technically competent group responsible for in-depth review of the data, methodology, and results; and (2) a scientifically literate but not technically adept group, whose main interest is in the implications of the analysis for the broader drug development program. We recommend a generalized question-based approach with 6 questions that need to be addressed throughout the report. We recommend 8 sections (Synopsis, Introduction, Data, Methods, Results, Discussion, Conclusions, Appendix) with suggestions for the target audience and level of detail for each section. A section providing general expectations regarding population PK reporting from a regulatory perspective is also included. We consider this an important step toward industrialization of the field of pharmacometrics such that a nontechnical audience also understands the role of pharmacometric analyses in decision making. Population PK reports were chosen as representative reports to derive these recommendations; however, the guiding principles presented here are applicable for all pharmacometric reports

  16. Reporting guidelines for population pharmacokinetic analyses.

    PubMed

    Dykstra, Kevin; Mehrotra, Nitin; Tornøe, Christoffer Wenzel; Kastrissios, Helen; Patel, Bela; Al-Huniti, Nidal; Jadhav, Pravin; Wang, Yaning; Byon, Wonkyung

    2015-06-01

    The purpose of this work was to develop a consolidated set of guiding principles for reporting of population pharmacokinetic (PK) analyses based on input from a survey of practitioners as well as discussions between industry, consulting and regulatory scientists. The survey found that identification of population covariate effects on drug exposure and support for dose selection (where population PK frequently serves as preparatory analysis to exposure-response modeling) are the main areas of influence for population PK analysis. The proposed guidelines consider two main purposes of population PK reports (1) to present key analysis findings and their impact on drug development decisions, and (2) as documentation of the analysis methods for the dual purpose of enabling review of the analysis and facilitating future use of the models. This work also identified two main audiences for the reports: (1) a technically competent group responsible for in-depth review of the data, methodology, and results, and (2) a scientifically literate, but not technically adept group, whose main interest is in the implications of the analysis for the broader drug development program. We recommend a generalized question-based approach with six questions that need to be addressed throughout the report. We recommend eight sections (Synopsis, Introduction, Data, Methods, Results, Discussion, Conclusions, Appendix) with suggestions for the target audience and level of detail for each section. A section providing general expectations regarding population PK reporting from a regulatory perspective is also included. We consider this an important step towards industrialization of the field of pharmacometrics such that non-technical audience also understands the role of pharmacometrics analyses in decision making. Population PK reports were chosen as representative reports to derive these recommendations; however, the guiding principles presented here are applicable for all pharmacometric reports

  17. Database-Driven Analyses of Astronomical Spectra

    NASA Astrophysics Data System (ADS)

    Cami, Jan

    2012-03-01

    Spectroscopy is one of the most powerful tools to study the physical properties and chemical composition of very diverse astrophysical environments. In principle, each nuclide has a unique set of spectral features; thus, establishing the presence of a specific material at astronomical distances requires no more than finding a laboratory spectrum of the right material that perfectly matches the astronomical observations. Once the presence of a substance is established, a careful analysis of the observational characteristics (wavelengths or frequencies, intensities, and line profiles) allows one to determine many physical parameters of the environment in which the substance resides, such as temperature, density, velocity, and so on. Because of this great diagnostic potential, ground-based and space-borne astronomical observatories often include instruments to carry out spectroscopic analyses of various celestial objects and events. Of particular interest is molecular spectroscopy at infrared wavelengths. From the spectroscopic point of view, molecules differ from atoms in their ability to vibrate and rotate, and quantum physics inevitably causes those motions to be quantized. The energies required to excite vibrations or rotations are such that vibrational transitions generally occur at infrared wavelengths, whereas pure rotational transitions typically occur at sub-mm wavelengths. Molecular vibration and rotation are coupled though, and thus at infrared wavelengths, one commonly observes a multitude of ro-vibrational transitions (see Figure 13.1). At lower spectral resolution, all transitions blend into one broad ro-vibrational molecular band. The isotope. Molecular spectroscopy thus allows us to see a difference of one neutron in an atomic nucleus that is located at astronomical distances! Since the detection of the first interstellar molecules (the CH [21] and CN [14] radicals), more than 150 species have been detected in space, ranging in size from diatomic

  18. Efficient ALL vs. ALL collision risk analyses

    NASA Astrophysics Data System (ADS)

    Escobar, D.; Paskowitz, M.; Agueda, A.; Garcia, G.; Molina, M.

    2011-09-01

    In recent years, the space debris has gained a lot of attention due to the increasing amount of uncontrolled man-made objects orbiting the Earth. This population poses a significant and constantly growing thread to operational satellites. In order to face this thread in an independent manner, ESA has launched an initiative for the development of a European SSA System where GMV is participating via several activities. Apart from those activities financed by ESA, GMV has developed closeap, a tool for efficient conjunction assessment and collision probability prediction. ESÁs NAPEOS has been selected as computational engine and numerical propagator to be used in the tool, which can be considered as an add-on to the standard NAPEOS package. closeap makes use of the same orbit computation, conjunction assessment and collision risk algorithms implemented in CRASS, but at the same time both systems are completely independent. Moreover, the implementation in closeap has been validated against CRASS with excellent results. This paper describes the performance improvements implemented in closeap at algorithm level to ensure that the most time demanding scenarios (e.g., all catalogued objects are analysed against each other - all vs. all scenarios -) can be analysed in a reasonable amount of time with commercial-off-the-shelf hardware. However, the amount of space debris increases steadily due to the human activities. Thus, the number of objects involved in a full collision assessment is expected to increase notably and, consequently, the computational cost, which scales as the square of the number of objects, will increase as well. Additionally, orbit propagation algorithms that are computationally expensive might be needed to predict more accurately the trajectories of the space debris. In order to cope with such computational needs, the next natural step in the development of collision assessment tools is the use of parallelization techniques. In this paper we investigate

  19. High perfomance liquid chromatography in pharmaceutical analyses.

    PubMed

    Nikolin, Branko; Imamović, Belma; Medanhodzić-Vuk, Saira; Sober, Miroslav

    2004-05-01

    In testing the pre-sale procedure the marketing of drugs and their control in the last ten years, high performance liquid chromatography replaced numerous spectroscopic methods and gas chromatography in the quantitative and qualitative analysis. In the first period of HPLC application it was thought that it would become a complementary method of gas chromatography, however, today it has nearly completely replaced gas chromatography in pharmaceutical analysis. The application of the liquid mobile phase with the possibility of transformation of mobilized polarity during chromatography and all other modifications of mobile phase depending upon the characteristics of substance which are being tested, is a great advantage in the process of separation in comparison to other methods. The greater choice of stationary phase is the next factor which enables realization of good separation. The separation line is connected to specific and sensitive detector systems, spectrafluorimeter, diode detector, electrochemical detector as other hyphernated systems HPLC-MS and HPLC-NMR, are the basic elements on which is based such wide and effective application of the HPLC method. The purpose high performance liquid chromatography (HPLC) analysis of any drugs is to confirm the identity of a drug and provide quantitative results and also to monitor the progress of the therapy of a disease.1) Measuring presented on the Fig. 1. is chromatogram obtained for the plasma of depressed patients 12 h before oral administration of dexamethasone. It may also be used to further our understanding of the normal and disease process in the human body trough biomedical and therapeutically research during investigation before of the drugs registration. The analyses of drugs and metabolites in biological fluids, particularly plasma, serum or urine is one of the most demanding but one of the most common uses of high performance of liquid chromatography. Blood, plasma or serum contains numerous endogenous

  20. Growth curve analyses in selected duck lines.

    PubMed

    Maruyama, K; Vinyard, B; Akbar, M K; Shafer, D J; Turk, C M

    2001-12-01

    1. Growth patterns of male ducks from 4 lines (lines A, B, C and D) selected for market weight were analysed and compared to growth patterns of ducks in the respective line 7 generations earlier. Growth curves were analysed using procedures derived from the Weibull sigmoidal function and the linear-linear relative growth rate model and simple allometry. 2. The ducks were fed ad libitum under 24-h lighting throughout the experiment. At weekly intervals from the time of hatch through 70 d of age, 16 ducks from each line were killed to determine body, carcase, breast-muscle, leg and thigh-muscle, and abdominal fat weights. 3. Line A was the heaviest line, followed by line B, line C and line D. However, body weight, carcase weight and breast-muscle weight at 49 d of age were not significantly different between lines A and B. After 7 generations of selection, the breast-muscle yield was increased to >19% and the abdominal fat percent was reduced to <1.4% in all lines. 4. The Weibull growth curve analysis of body weight showed an increase in the asymptotes during selection, while the age of the inflection point remained constant in all lines (21.3 to 26.0 d). For breast-muscle growth, ducks reached the inflection point 12.8 to 14.3 d later than for body weight. Between line A and line B, asymptotes for body weight, asymptotes for breast-muscle weight and allometric growth coefficients of breast muscle and leg and thigh muscles from 14 to 49 d were not significantly different. 5. The relative growth rate model discriminated body and breast-muscle growth patterns of line A and line B. The initial decline in the relative body growth rate was less and the time to reach the transition was longer in line A than line B. On the other hand, the initial decline in the relative breast-muscle growth rate was greater in line A than line B. PMID:11811908

  1. Applications of Parallel Processing in Configuration Analyses

    NASA Technical Reports Server (NTRS)

    Sundaram, Ppchuraman; Hager, James O.; Biedron, Robert T.

    1999-01-01

    The paper presents the recent progress made towards developing an efficient and user-friendly parallel environment for routine analysis of large CFD problems. The coarse-grain parallel version of the CFL3D Euler/Navier-Stokes analysis code, CFL3Dhp, has been ported onto most available parallel platforms. The CFL3Dhp solution accuracy on these parallel platforms has been verified with the CFL3D sequential analyses. User-friendly pre- and post-processing tools that enable a seamless transfer from sequential to parallel processing have been written. Static load balancing tool for CFL3Dhp analysis has also been implemented for achieving good parallel efficiency. For large problems, load balancing efficiency as high as 95% can be achieved even when large number of processors are used. Linear scalability of the CFL3Dhp code with increasing number of processors has also been shown using a large installed transonic nozzle boattail analysis. To highlight the fast turn-around time of parallel processing, the TCA full configuration in sideslip Navier-Stokes drag polar at supersonic cruise has been obtained in a day. CFL3Dhp is currently being used as a production analysis tool.

  2. DNA microarray analyses in higher plants.

    PubMed

    Galbraith, David W

    2006-01-01

    DNA microarrays were originally devised and described as a convenient technology for the global analysis of plant gene expression. Over the past decade, their use has expanded enormously to cover all kingdoms of living organisms. At the same time, the scope of applications of microarrays has increased beyond expression analyses, with plant genomics playing a leadership role in the on-going development of this technology. As the field has matured, the rate-limiting step has moved from that of the technical process of data generation to that of data analysis. We currently face major problems in dealing with the accumulating datasets, not simply with respect to how to archive, access, and process the huge amounts of data that have been and are being produced, but also in determining the relative quality of the different datasets. A major recognized concern is the appropriate use of statistical design in microarray experiments, without which the datasets are rendered useless. A vigorous area of current research involves the development of novel statistical tools specifically for microarray experiments. This article describes, in a necessarily selective manner, the types of platforms currently employed in microarray research and provides an overview of recent activities using these platforms in plant biology.

  3. Phylogenomic Analyses Support Traditional Relationships within Cnidaria

    PubMed Central

    Zapata, Felipe; Goetz, Freya E.; Smith, Stephen A.; Howison, Mark; Siebert, Stefan; Church, Samuel H.; Sanders, Steven M.; Ames, Cheryl Lewis; McFadden, Catherine S.; France, Scott C.; Daly, Marymegan; Collins, Allen G.; Haddock, Steven H. D.; Dunn, Casey W.; Cartwright, Paulyn

    2015-01-01

    Cnidaria, the sister group to Bilateria, is a highly diverse group of animals in terms of morphology, lifecycles, ecology, and development. How this diversity originated and evolved is not well understood because phylogenetic relationships among major cnidarian lineages are unclear, and recent studies present contrasting phylogenetic hypotheses. Here, we use transcriptome data from 15 newly-sequenced species in combination with 26 publicly available genomes and transcriptomes to assess phylogenetic relationships among major cnidarian lineages. Phylogenetic analyses using different partition schemes and models of molecular evolution, as well as topology tests for alternative phylogenetic relationships, support the monophyly of Medusozoa, Anthozoa, Octocorallia, Hydrozoa, and a clade consisting of Staurozoa, Cubozoa, and Scyphozoa. Support for the monophyly of Hexacorallia is weak due to the equivocal position of Ceriantharia. Taken together, these results further resolve deep cnidarian relationships, largely support traditional phylogenetic views on relationships, and provide a historical framework for studying the evolutionary processes involved in one of the most ancient animal radiations. PMID:26465609

  4. Analyse de plomb dans les peintures

    NASA Astrophysics Data System (ADS)

    Broll, N.; Frezouls, J.-M.

    2002-07-01

    The analysis of lead in paints was previously used for the characterisation of pigments. In this way, the analysis is able to specify the century of the painting of a work of art. Recently this technique was also used to determine the toxicity of lead paints in building. This paper compared the result of several X-ray fluorescence spectrometer, either wave length/energy dispersion laboratory apparatus or X-ray microtube/radioactive source portable equipment's. L'analyse du plomb dans les peintures a jusqu'à présent été appliquée essentiellement pour caractériser les pigments lors de leur fabrication et pour identifier des rouvres d'art. Récemment cette technique est également utilisée pour déterminer la toxicité des peintures au plomb dans les bâtiments. Nous avons comparé les performances de plusieurs spectromètres de fluorescence X, soit de laboratoire à dispersion en longueur d'onde ou à dispersion en énergie (avec tube à rayonsX), soit portable avec source radioactive ou tube à rayons X.

  5. Comparative sequence analyses of sixteen reptilian paramyxoviruses

    USGS Publications Warehouse

    Ahne, W.; Batts, W.N.; Kurath, G.; Winton, J.R.

    1999-01-01

    Viral genomic RNA of Fer-de-Lance virus (FDLV), a paramyxovirus highly pathogenic for reptiles, was reverse transcribed and cloned. Plasmids with significant sequence similarities to the hemagglutinin-neuraminidase (HN) and polymerase (L) genes of mammalian paramyxoviruses were identified by BLAST search. Partial sequences of the FDLV genes were used to design primers for amplification by nested polymerase chain reaction (PCR) and sequencing of 518-bp L gene and 352-bp HN gene fragments from a collection of 15 previously uncharacterized reptilian paramyxoviruses. Phylogenetic analyses of the partial L and HN sequences produced similar trees in which there were two distinct subgroups of isolates that were supported with maximum bootstrap values, and several intermediate isolates. Within each subgroup the nucleotide divergence values were less than 2.5%, while the divergence between the two subgroups was 20-22%. This indicated that the two subgroups represent distinct virus species containing multiple virus strains. The five intermediate isolates had nucleotide divergence values of 11-20% and may represent additional distinct species. In addition to establishing diversity among reptilian paramyxoviruses, the phylogenetic groupings showed some correlation with geographic location, and clearly demonstrated a low level of host species-specificity within these viruses. Copyright (C) 1999 Elsevier Science B.V.

  6. Stereological analyses of the whole human pancreas

    PubMed Central

    Poudel, Ananta; Fowler, Jonas L.; Zielinski, Mark C.; Kilimnik, German; Hara, Manami

    2016-01-01

    The large size of human tissues requires a practical stereological approach to perform a comprehensive analysis of the whole organ. We have developed a method to quantitatively analyze the whole human pancreas, as one of the challenging organs to study, in which endocrine cells form various sizes of islets that are scattered unevenly throughout the exocrine pancreas. Furthermore, the human pancreas possesses intrinsic characteristics of intra-individual variability, i.e. regional differences in endocrine cell/islet distribution, and marked inter-individual heterogeneity regardless of age, sex and disease conditions including obesity and diabetes. The method is built based on large-scale image capture, computer-assisted unbiased image analysis and quantification, and further mathematical analyses, using widely-used software such as Fiji/ImageJ and MATLAB. The present study includes detailed protocols of every procedure as well as all the custom-written computer scripts, which can be modified according to specific experimental plans and specimens of interest. PMID:27658965

  7. Isolation and Analyses of Axonal Ribonucleoprotein Complexes

    PubMed Central

    Doron-Mandel, Ella; Alber, Stefanie; Oses, Juan A.; Medzihradszky, Katalin F.; Burlingame, Alma L.; Fainzilber, Mike; Twiss, Jeffery L.; Lee, Seung Joon

    2016-01-01

    Cytoskeleton-dependent RNA transport and local translation in axons are gaining increased attention as key processes in the maintenance and functioning of neurons. Specific axonal transcripts have been found to play roles in many aspects of axonal physiology including axon guidance, axon survival, axon to soma communication, injury response and regeneration. This axonal transcriptome requires long-range transport that is achieved by motor proteins carrying transcripts as messenger ribonucleoprotein (mRNP) complexes along microtubules. Other than transport, the mRNP complex plays a major role in the generation, maintenance and regulation of the axonal transcriptome. Identification of axonal RNA binding proteins (RBPs) and analyses of the dynamics of their mRNPs are of high interest to the field. Here we describe methods for the study of interactions between RNA and proteins in axons. First, we describe a protocol for identifying binding proteins for an RNA of interest by using RNA affinity chromatography. Subsequently, we discuss immunoprecipitation (IP) methods allowing the dissection of protein- RNA and protein-protein interactions in mRNPs under various physiological conditions. PMID:26794529

  8. CFD analyses of coolant channel flowfields

    NASA Technical Reports Server (NTRS)

    Yagley, Jennifer A.; Feng, Jinzhang; Merkle, Charles L.

    1993-01-01

    The flowfield characteristics in rocket engine coolant channels are analyzed by means of a numerical model. The channels are characterized by large length to diameter ratios, high Reynolds numbers, and asymmetrical heating. At representative flow conditions, the channel length is approximately twice the hydraulic entrance length so that fully developed conditions would be reached for a constant property fluid. For the supercritical hydrogen that is used as the coolant, the strong property variations create significant secondary flows in the cross-plane which have a major influence on the flow and the resulting heat transfer. Comparison of constant and variable property solutions show substantial differences. In addition, the property variations prevent fully developed flow. The density variation accelerates the fluid in the channels increasing the pressure drop without an accompanying increase in heat flux. Analyses of the inlet configuration suggest that side entry from a manifold can affect the development of the velocity profile because of vortices generated as the flow enters the channel. Current work is focused on studying the effects of channel bifurcation on the flow field and the heat transfer characteristics.

  9. Trend Analyses of Nitrate in Danish Groundwater

    NASA Astrophysics Data System (ADS)

    Hansen, B.; Thorling, L.; Dalgaard, T.; Erlandsen, M.

    2012-04-01

    This presentation assesses the long-term development in the oxic groundwater nitrate concentration and nitrogen (N) loss due to intensive farming in Denmark. Firstly, up to 20-year time-series from the national groundwater monitoring network enable a statistically systematic analysis of distribution, trends and trend reversals in the groundwater nitrate concentration. Secondly, knowledge about the N surplus in Danish agriculture since 1950 is used as an indicator of the potential loss of N. Thirdly, groundwater recharge CFC (Chlorofluorocarbon) age determination allows linking of the first two dataset. The development in the nitrate concentration of oxic groundwater clearly mirrors the development in the national agricultural N surplus, and a corresponding trend reversal is found in groundwater. Regulation and technical improvements in the intensive farming in Denmark have succeeded in decreasing the N surplus by 40% since the mid 1980s while at the same time maintaining crop yields and increasing the animal production of especially pigs. Trend analyses prove that the youngest (0-15 years old) oxic groundwater shows more pronounced significant downward nitrate trends (44%) than the oldest (25-50 years old) oxic groundwater (9%). This amounts to clear evidence of the effect of reduced nitrate leaching on groundwater nitrate concentrations in Denmark. Are the Danish groundwater monitoring strategy obtimal for detection of nitrate trends? Will the nitrate concentrations in Danish groundwater continue to decrease or are the Danish nitrate concentration levels now appropriate according to the Water Framework Directive?

  10. Evaluation of the Hitachi 717 analyser.

    PubMed

    Biosca, C; Antoja, F; Sierra, C; Douezi, H; Macià, M; Alsina, M J; Galimany, R

    1989-01-01

    The selective multitest Boehringer Mannheim Hitachi 717 analyser was evaluated according to the guidelines of the Comisión de Instrumentación de la Sociedad Española de Química Clinica and the European Committee for Clinical Laboratory Standards. The evaluation was performed in two steps: examination of the analytical units and evaluation in routine operation.THE EVALUATION OF THE ANALYTICAL UNITS INCLUDED A PHOTOMETRIC STUDY: the inaccuracy is acceptable for 340 and 405 nm; the imprecision ranges from 0.12 to 0.95% at 340 nm and from 0.30 to 0.73 at 405 nm, the linearity shows some dispersion at low absorbance for NADH at 340 nm, the drift is negligible, the imprecision of the pipette delivery system increases when the sample pipette operates with 3 mul, the reagent pipette imprecision is acceptable and the temperature control system is good.UNDER ROUTINE WORKING CONDITIONS, SEVEN DETERMINATIONS WERE STUDIED: glucose, creatinine, iron, total protein, AST, ALP and calcium. The within-run imprecision (CV) ranged from 0.6% for total protein and AST to 6.9% for iron. The between run imprecision ranged from 2.4% for glucose to 9.7% for iron. Some contamination was found in the carry-over study. The relative inaccuracy is good for all the constituents assayed.

  11. Evaluation of the Olympus AU-510 analyser.

    PubMed

    Farré, C; Velasco, J; Ramón, F

    1991-01-01

    The selective multitest Olympus AU-510 analyser was evaluated according to the recommendations of the Comision de Instrumentacion de la Sociedad Española de Quimica Clinica and the European Committee for Clinical Laboratory Standards. The evaluation was carried out in two stages: an examination of the analytical units and then an evaluation in routine work conditions. The operational characteristics of the system were also studied.THE FIRST STAGE INCLUDED A PHOTOMETRIC STUDY: dependent on the absorbance, the inaccuracy varies between +0.5% to -0.6% at 405 nm and from -5.6% to 10.6% at 340 nm; the imprecision ranges between -0.22% and 0.56% at 405 nm and between 0.09% and 2.74% at 340 nm. Linearity was acceptable, apart from a very low absorbance for NADH at 340 nm; and the imprecision of the serum sample pipetter was satisfactory.TWELVE SERUM ANALYTES WERE STUDIED UNDER ROUTINE CONDITIONS: glucose, urea urate, cholesterol, triglycerides, total bilirubin, creatinine, phosphate, iron, aspartate aminotransferase, alanine aminotransferase and gamma-glutamyl transferase.The within-run imprecision (CV%) ranged from 0.67% for phosphate to 2.89% for iron and the between-run imprecision from 0.97% for total bilirubin to 7.06% for iron. There was no carryover in a study of the serum sample pipetter. Carry-over studies with the reagent and sample pipetters shows some cross contamination in the iron assay.

  12. Biomechanical analyses of rising from a chair.

    PubMed

    Schultz, A B; Alexander, N B; Ashton-Miller, J A

    1992-12-01

    Quantification of the biomechanical factors that underlie the inability to rise from a chair can help explain why this disability occurs and can aid in the design of chairs and of therapeutic intervention programs. Experimental data collected earlier from 17 young adult and two groups of elderly subjects, 23 healthy and 11 impaired, rising from a standard chair under controlled conditions were analyzed using a planar biomechanical model. The joint torque strength requirements and the location of the floor reaction force at liftoff from the seat in the different groups and under several conditions were calculated. Analyses were also made of how body configurations and the use of hand force affect these joint torques and reaction locations. In all three groups, the required torques at liftoff were modest compared to literature data on voluntary strengths. Among the three groups rising with the use of hands, at the time of liftoff from the seat, the impaired old subjects, on an average, placed the reaction force the most anterior, the healthy old subjects placed it intermediately and the young subjects placed it the least anterior, within the foot support area. Moreover, the results suggest that, at liftoff, all subjects placed more importance on locating the floor reaction force to achieve acceptable postural stability than on diminishing the magnitudes of the needed joint muscle strengths.

  13. PRECLOSURE CONSEQUENCE ANALYSES FOR LICENSE APPLICATION

    SciTech Connect

    S. Tsai

    2005-01-12

    Radiological consequence analyses are performed for potential releases from normal operations in surface and subsurface facilities and from Category 1 and Category 2 event sequences during the preclosure period. Surface releases from normal repository operations are primarily from radionuclides released from opening a transportation cask during dry transfer operations of spent nuclear fuel (SNF) in Dry Transfer Facility 1 (DTF 1), Dry Transfer Facility 2 (DTF 2), the Canister Handling facility (CHF), or the Fuel Handling Facility (FHF). Subsurface releases from normal repository operations are from resuspension of waste package surface contamination and neutron activation of ventilated air and silica dust from host rock in the emplacement drifts. The purpose of this calculation is to demonstrate that the preclosure performance objectives, specified in 10 CFR 63.111(a) and 10 CFR 63.111(b), have been met for the proposed design and operations in the geologic repository operations area. Preclosure performance objectives are discussed in Section 6.2.3 and are summarized in Tables 1 and 2.

  14. Informative prior distributions for ELISA analyses.

    PubMed

    Klauenberg, Katy; Walzel, Monika; Ebert, Bernd; Elster, Clemens

    2015-07-01

    Immunoassays are capable of measuring very small concentrations of substances in solutions and have an immense range of application. Enzyme-linked immunosorbent assay (ELISA) tests in particular can detect the presence of an infection, of drugs, or hormones (as in the home pregnancy test). Inference of an unknown concentration via ELISA usually involves a non-linear heteroscedastic regression and subsequent prediction, which can be carried out in a Bayesian framework. For such a Bayesian inference, we are developing informative prior distributions based on extensive historical ELISA tests as well as theoretical considerations. One consideration regards the quality of the immunoassay leading to two practical requirements for the applicability of the priors. Simulations show that the additional prior information can lead to inferences which are robust to reasonable perturbations of the model and changes in the design of the data. On real data, the applicability is demonstrated across different laboratories, for different analytes and laboratory equipment as well as for previous and current ELISAs with sigmoid regression function. Consistency checks on real data (similar to cross-validation) underpin the adequacy of the suggested priors. Altogether, the new priors may improve concentration estimation for ELISAs that fulfill certain design conditions, by extending the range of the analyses, decreasing the uncertainty, or giving more robust estimates. Future use of these priors is straightforward because explicit, closed-form expressions are provided. This work encourages development and application of informative, yet general, prior distributions for other types of immunoassays.

  15. Verification against perturbed analyses and observations

    NASA Astrophysics Data System (ADS)

    Bowler, N. E.; Cullen, M. J. P.; Piccolo, C.

    2015-07-01

    It has long been known that verification of a forecast against the sequence of analyses used to produce those forecasts can under-estimate the magnitude of forecast errors. Here we show that under certain conditions the verification of a short-range forecast against a perturbed analysis coming from an ensemble data assimilation scheme can give the same root-mean-square error as verification against the truth. This means that a perturbed analysis can be used as a reliable proxy for the truth. However, the conditions required for this result to hold are rather restrictive: the analysis must be optimal, the ensemble spread must be equal to the error in the mean, the ensemble size must be large and the forecast being verified must be the background forecast used in the data assimilation. Although these criteria are unlikely to be met exactly it becomes clear that for most cases verification against a perturbed analysis gives better results than verification against an unperturbed analysis. We demonstrate the application of these results in a idealised model framework and a numerical weather prediction context. In deriving this result we recall that an optimal (Kalman) analysis is one for which the analysis increments are uncorrelated with the analysis errors.

  16. Genomic analyses of the CAM plant pineapple.

    PubMed

    Zhang, Jisen; Liu, Juan; Ming, Ray

    2014-07-01

    The innovation of crassulacean acid metabolism (CAM) photosynthesis in arid and/or low CO2 conditions is a remarkable case of adaptation in flowering plants. As the most important crop that utilizes CAM photosynthesis, the genetic and genomic resources of pineapple have been developed over many years. Genetic diversity studies using various types of DNA markers led to the reclassification of the two genera Ananas and Pseudananas and nine species into one genus Ananas and two species, A. comosus and A. macrodontes with five botanical varieties in A. comosus. Five genetic maps have been constructed using F1 or F2 populations, and high-density genetic maps generated by genotype sequencing are essential resources for sequencing and assembling the pineapple genome and for marker-assisted selection. There are abundant expression sequence tag resources but limited genomic sequences in pineapple. Genes involved in the CAM pathway has been analysed in several CAM plants but only a few of them are from pineapple. A reference genome of pineapple is being generated and will accelerate genetic and genomic research in this major CAM crop. This reference genome of pineapple provides the foundation for studying the origin and regulatory mechanism of CAM photosynthesis, and the opportunity to evaluate the classification of Ananas species and botanical cultivars.

  17. Reproducibility of neuroimaging analyses across operating systems

    PubMed Central

    Glatard, Tristan; Lewis, Lindsay B.; Ferreira da Silva, Rafael; Adalat, Reza; Beck, Natacha; Lepage, Claude; Rioux, Pierre; Rousseau, Marc-Etienne; Sherif, Tarek; Deelman, Ewa; Khalili-Mahani, Najmeh; Evans, Alan C.

    2015-01-01

    Neuroimaging pipelines are known to generate different results depending on the computing platform where they are compiled and executed. We quantify these differences for brain tissue classification, fMRI analysis, and cortical thickness (CT) extraction, using three of the main neuroimaging packages (FSL, Freesurfer and CIVET) and different versions of GNU/Linux. We also identify some causes of these differences using library and system call interception. We find that these packages use mathematical functions based on single-precision floating-point arithmetic whose implementations in operating systems continue to evolve. While these differences have little or no impact on simple analysis pipelines such as brain extraction and cortical tissue classification, their accumulation creates important differences in longer pipelines such as subcortical tissue classification, fMRI analysis, and cortical thickness extraction. With FSL, most Dice coefficients between subcortical classifications obtained on different operating systems remain above 0.9, but values as low as 0.59 are observed. Independent component analyses (ICA) of fMRI data differ between operating systems in one third of the tested subjects, due to differences in motion correction. With Freesurfer and CIVET, in some brain regions we find an effect of build or operating system on cortical thickness. A first step to correct these reproducibility issues would be to use more precise representations of floating-point numbers in the critical sections of the pipelines. The numerical stability of pipelines should also be reviewed. PMID:25964757

  18. Recent Advances in Cellular Glycomic Analyses

    PubMed Central

    Furukawa, Jun-ichi; Fujitani, Naoki; Shinohara, Yasuro

    2013-01-01

    A large variety of glycans is intricately located on the cell surface, and the overall profile (the glycome, given the entire repertoire of glycoconjugate-associated sugars in cells and tissues) is believed to be crucial for the diverse roles of glycans, which are mediated by specific interactions that control cell-cell adhesion, immune response, microbial pathogenesis and other cellular events. The glycomic profile also reflects cellular alterations, such as development, differentiation and cancerous change. A glycoconjugate-based approach would therefore be expected to streamline discovery of novel cellular biomarkers. Development of such an approach has proven challenging, due to the technical difficulties associated with the analysis of various types of cellular glycomes; however, recent progress in the development of analytical methodologies and strategies has begun to clarify the cellular glycomics of various classes of glycoconjugates. This review focuses on recent advances in the technical aspects of cellular glycomic analyses of major classes of glycoconjugates, including N- and O-linked glycans, derived from glycoproteins, proteoglycans and glycosphingolipids. Articles that unveil the glycomics of various biologically important cells, including embryonic and somatic stem cells, induced pluripotent stem (iPS) cells and cancer cells, are discussed. PMID:24970165

  19. Cyanide analyses for risk and treatability assessments

    SciTech Connect

    MacFarlane, I.D.; Elseroad, H.J.; Pergrin, D.E.; Logan, C.M.

    1994-12-31

    Cyanide, an EPA priority pollutant and target analyte, is typically measured as total. However, cyanide complexation, information which is not acquired through total cyanide analysis, is often a driver of cyanide toxicity and treatability. A case study of a former manufacture gas plant (MGP) is used to demonstrate the usability of various cyanide analytical methods for risk and treatability assessments. Several analytical methods, including cyanide amenable to chlorination and weak acid dissociable cyanide help test the degree of cyanide complexation. Generally, free or uncomplexed cyanide is more biologically available, toxic, and reactive than complexed cyanide. Extensive site testing has shown that free and weakly dissociable cyanide composes only a small fraction of total cyanide as would be expected from the literature, and that risk assessment will be more realistic considering cyanide form. Likewise, aqueous treatment for cyanide can be properly tested if cyanide form is accounted for. Weak acid dissociable cyanide analyses proved to be the most reliable (and potentially acceptable) cyanide method, as well as represent the most toxic and reactive cyanide forms.

  20. Transportation systems analyses. Volume 1: Executive summary

    NASA Astrophysics Data System (ADS)

    1992-11-01

    The principal objective is to accomplish a systems engineering assessment of the nation's space transportation infrastructure. This analysis addresses the necessary elements to perform crew delivery and return, cargo transfer, cargo delivery and return, payload servicing, and the exploration of the Moon and Mars. Specific elements analyzed, but not limited to, include: the Space Exploration Initiative (SEI), the National Launch System (NLS), the current expendable launch vehicle (ELV) fleet, ground facilities, the Space Station Freedom (SSF), and other civil, military and commercial payloads. The performance of this study entails maintaining a broad perspective on the large number of transportation elements that could potentially comprise the U.S. space infrastructure over the next several decades. To perform this systems evaluation, top-level trade studies are conducted to enhance our understanding of the relationship between elements of the infrastructure. This broad 'infrastructure-level perspective' permits the identification of preferred infrastructures. Sensitivity analyses are performed to assure the credibility and usefulness of study results. Conceptual studies of transportation elements contribute to the systems approach by identifying elements (such as ETO node and transfer/excursion vehicles) needed in current and planned transportation systems. These studies are also a mechanism to integrate the results of relevant parallel studies.

  1. Bayesian network learning for natural hazard analyses

    NASA Astrophysics Data System (ADS)

    Vogel, K.; Riggelsen, C.; Korup, O.; Scherbaum, F.

    2014-09-01

    Modern natural hazards research requires dealing with several uncertainties that arise from limited process knowledge, measurement errors, censored and incomplete observations, and the intrinsic randomness of the governing processes. Nevertheless, deterministic analyses are still widely used in quantitative hazard assessments despite the pitfall of misestimating the hazard and any ensuing risks. In this paper we show that Bayesian networks offer a flexible framework for capturing and expressing a broad range of uncertainties encountered in natural hazard assessments. Although Bayesian networks are well studied in theory, their application to real-world data is far from straightforward, and requires specific tailoring and adaptation of existing algorithms. We offer suggestions as how to tackle frequently arising problems in this context and mainly concentrate on the handling of continuous variables, incomplete data sets, and the interaction of both. By way of three case studies from earthquake, flood, and landslide research, we demonstrate the method of data-driven Bayesian network learning, and showcase the flexibility, applicability, and benefits of this approach. Our results offer fresh and partly counterintuitive insights into well-studied multivariate problems of earthquake-induced ground motion prediction, accurate flood damage quantification, and spatially explicit landslide prediction at the regional scale. In particular, we highlight how Bayesian networks help to express information flow and independence assumptions between candidate predictors. Such knowledge is pivotal in providing scientists and decision makers with well-informed strategies for selecting adequate predictor variables for quantitative natural hazard assessments.

  2. Characterization of branch complexity by fractal analyses

    USGS Publications Warehouse

    Alados, C.L.; Escos, J.; Emlen, J.M.; Freeman, D.C.

    1999-01-01

    The comparison between complexity in the sense of space occupancy (box-counting fractal dimension D(c) and information dimension D1) and heterogeneity in the sense of space distribution (average evenness index f and evenness variation coefficient J(cv)) were investigated in mathematical fractal objects and natural branch structures. In general, increased fractal dimension was paired with low heterogeneity. Comparisons between branch architecture in Anthyllis cytisoides under different slope exposure and grazing impact revealed that branches were more complex and more homogeneously distributed for plants on northern exposures than southern, while grazing had no impact during a wet year. Developmental instability was also investigated by the statistical noise of the allometric relation between internode length and node order. In conclusion, our study demonstrated that fractal dimension of branch structure can be used to analyze the structural organization of plants, especially if we consider not only fractal dimension but also shoot distribution within the canopy (lacunarity). These indexes together with developmental instability analyses are good indicators of growth responses to the environment.

  3. Local spin analyses using density functional theory

    NASA Astrophysics Data System (ADS)

    Abate, Bayileyegn; Peralta, Juan

    Local spin analysis is a valuable technique in computational investigations magnetic interactions on mono- and polynuclear transition metal complexes, which play vital roles in catalysis, molecular magnetism, artificial photosynthesis, and several other commercially important materials. The relative size and complex electronic structure of transition metal complexes often prohibits the use of multi-determinant approaches, and hence, practical calculations are often limited to single-determinant methods. Density functional theory (DFT) has become one of the most successful and widely used computational tools for the electronic structure study of complex chemical systems; transition metal complexes in particular. Within the DFT formalism, a more flexible and complete theoretical modeling of transition metal complexes can be achieved by considering noncollinear spins, in which the spin density is 'allowed to' adopt noncollinear structures in stead of being constrained to align parallel/antiparallel to a universal axis of magnetization. In this meeting, I will present local spin analyses results obtained using different DFT functionals. Local projection operators are used to decompose the expectation value of the total spin operator; first introduced by Clark and Davidson.

  4. Seismic Soil-Structure Interaction Analyses of a Deeply Embedded Model Reactor – SASSI Analyses

    SciTech Connect

    Nie J.; Braverman J.; Costantino, M.

    2013-10-31

    This report summarizes the SASSI analyses of a deeply embedded reactor model performed by BNL and CJC and Associates, as part of the seismic soil-structure interaction (SSI) simulation capability project for the NEAMS (Nuclear Energy Advanced Modeling and Simulation) Program of the Department of Energy. The SASSI analyses included three cases: 0.2 g, 0.5 g, and 0.9g, all of which refer to nominal peak accelerations at the top of the bedrock. The analyses utilized the modified subtraction method (MSM) for performing the seismic SSI evaluations. Each case consisted of two analyses: input motion in one horizontal direction (X) and input motion in the vertical direction (Z), both of which utilized the same in-column input motion. Besides providing SASSI results for use in comparison with the time domain SSI results obtained using the DIABLO computer code, this study also leads to the recognition that the frequency-domain method should be modernized so that it can better serve its mission-critical role for analysis and design of nuclear power plants.

  5. Integrated Field Analyses of Thermal Springs

    NASA Astrophysics Data System (ADS)

    Shervais, K.; Young, B.; Ponce-Zepeda, M. M.; Rosove, S.

    2011-12-01

    A group of undergraduate researchers through the SURE internship offered by the Southern California Earthquake Center (SCEC) have examined thermal springs in southern Idaho, northern Utah as well as mud volcanoes in the Salton Sea, California. We used an integrated approach to estimate the setting and maximum temperature, including water chemistry, Ipad-based image and data-base management, microbiology, and gas analyses with a modified Giggenbach sampler.All springs were characterized using GISRoam (tmCogent3D). We are performing geothermometry calculations as well as comparisons with temperature gradient data on the results while also analyzing biological samples. Analyses include water temperature, pH, electrical conductivity, and TDS measured in the field. Each sample is sealed and chilled and delivered to a water lab within 12 hours.Temperatures are continuously monitored with the use of Solinst Levelogger Juniors. Through partnership with a local community college geology club, we receive results on a monthly basis and are able to process initial data earlier in order to evaluate data over a longer time span. The springs and mudpots contained microbial organisms which were analyzed using methods of single colony isolation, polymerase chain reaction, and DNA sequencing showing the impact of the organisms on the springs or vice versa. Soon we we will collect gas samples at sites that show signs of gas. This will be taken using a hybrid of the Giggenbach method and our own methods. Drawing gas samples has proven a challenge, however we devised a method to draw out gas samples utilizing the Giggenbach flask, transferring samples to glass blood sample tubes, replacing NaOH in the Giggenbach flask, and evacuating it in the field for multiple samples using a vacuum pump. We also use a floating platform devised to carry and lower a levelogger, to using an in-line fuel filter from a tractor in order to keep mud from contaminating the equipment.The use of raster

  6. Fracturing and brittleness index analyses of shales

    NASA Astrophysics Data System (ADS)

    Barnhoorn, Auke; Primarini, Mutia; Houben, Maartje

    2016-04-01

    The formation of a fracture network in rocks has a crucial control on the flow behaviour of fluids. In addition, an existing network of fractures , influences the propagation of new fractures during e.g. hydraulic fracturing or during a seismic event. Understanding of the type and characteristics of the fracture network that will be formed during e.g. hydraulic fracturing is thus crucial to better predict the outcome of a hydraulic fracturing job. For this, knowledge of the rock properties is crucial. The brittleness index is often used as a rock property that can be used to predict the fracturing behaviour of a rock for e.g. hydraulic fracturing of shales. Various terminologies of the brittleness index (BI1, BI2 and BI3) exist based on mineralogy, elastic constants and stress-strain behaviour (Jin et al., 2014, Jarvie et al., 2007 and Holt et al., 2011). A maximum brittleness index of 1 predicts very good and efficient fracturing behaviour while a minimum brittleness index of 0 predicts a much more ductile shale behaviour. Here, we have performed systematic petrophysical, acoustic and geomechanical analyses on a set of shale samples from Whitby (UK) and we have determined the three different brittleness indices on each sample by performing all the analyses on each of the samples. We show that each of the three brittleness indices are very different for the same sample and as such it can be concluded that the brittleness index is not a good predictor of the fracturing behaviour of shales. The brittleness index based on the acoustic data (BI1) all lie around values of 0.5, while the brittleness index based on the stress strain data (BI2) give an average brittleness index around 0.75, whereas the mineralogy brittleness index (BI3) predict values below 0.2. This shows that by using different estimates of the brittleness index different decisions can be made for hydraulic fracturing. If we would rely on the mineralogy (BI3), the Whitby mudstone is not a suitable

  7. Phylogenomic analyses and improved resolution of Cetartiodactyla.

    PubMed

    Zhou, Xuming; Xu, Shixia; Yang, Yunxia; Zhou, Kaiya; Yang, Guang

    2011-11-01

    The remarkable antiquity, diversity, and significance in the ecology and evolution of Cetartiodactyla have inspired numerous attempts to resolve their phylogenetic relationships. However, previous analyses based on limited samples of nuclear genes or mitochondrial DNA sequences have generated results that were either inconsistent with one another, weakly supported, or highly sensitive to analytical conditions. Here, we present strongly supported results based upon over 1.4 Mb of an aligned DNA sequence matrix from 110 single-copy nuclear protein-coding genes of 21 Cetartiodactyla species, which represent major Cetartiodactyla lineages, and three species of Perissodactyla and Carnivora as outgroups. Phylogenetic analysis of this newly developed genomic sequence data using a codon-based model and recently developed models of the rate autocorrelation resolved the phylogenetic relationships of the major cetartiodactylan lineages and of those lineages with a high degree of confidence. Cetacea was found to nest within Artiodactyla as the sister group of Hippopotamidae, and Tylopoda was corroborated as the sole base clade of Cetartiodactyla. Within Cetacea, the monophyletic status of Odontoceti relative to Mysticeti, the basal position of Physeteroidea in Odontoceti, the non-monophyly of the river dolphins, and the sister relationship between Delphinidae and Monodontidae+Phocoenidae were strongly supported. In particular, the groups of Tursiops (bottlenose dolphins) and Stenella (spotted dolphins) were validated as unnatural groups. Additionally, a very narrow time frame of ∼3 My (million years) was found for the rapid diversification of delphinids in the late Miocene, which made it difficult to resolve the phylogenetic relationships within the Delphinidae, especially for previous studies with limited data sets. The present study provides a statistically well-supported phylogenetic framework of Cetartiodactyla, which represents an important step toward ending some of

  8. On study design in neuroimaging heritability analyses

    NASA Astrophysics Data System (ADS)

    Koran, Mary Ellen; Li, Bo; Jahanshad, Neda; Thornton-Wells, Tricia A.; Glahn, David C.; Thompson, Paul M.; Blangero, John; Nichols, Thomas E.; Kochunov, Peter; Landman, Bennett A.

    2014-03-01

    Imaging genetics is an emerging methodology that combines genetic information with imaging-derived metrics to understand how genetic factors impact observable structural, functional, and quantitative phenotypes. Many of the most well-known genetic studies are based on Genome-Wide Association Studies (GWAS), which use large populations of related or unrelated individuals to associate traits and disorders with individual genetic factors. Merging imaging and genetics may potentially lead to improved power of association in GWAS because imaging traits may be more sensitive phenotypes, being closer to underlying genetic mechanisms, and their quantitative nature inherently increases power. We are developing SOLAR-ECLIPSE (SE) imaging genetics software which is capable of performing genetic analyses with both large-scale quantitative trait data and family structures of variable complexity. This program can estimate the contribution of genetic commonality among related subjects to a given phenotype, and essentially answer the question of whether or not the phenotype is heritable. This central factor of interest, heritability, offers bounds on the direct genetic influence over observed phenotypes. In order for a trait to be a good phenotype for GWAS, it must be heritable: at least some proportion of its variance must be due to genetic influences. A variety of family structures are commonly used for estimating heritability, yet the variability and biases for each as a function of the sample size are unknown. Herein, we investigate the ability of SOLAR to accurately estimate heritability models based on imaging data simulated using Monte Carlo methods implemented in R. We characterize the bias and the variability of heritability estimates from SOLAR as a function of sample size and pedigree structure (including twins, nuclear families, and nuclear families with grandparents).

  9. Finite Element analyses of soil bioengineered slopes

    NASA Astrophysics Data System (ADS)

    Tamagnini, Roberto; Switala, Barbara Maria; Sudan Acharya, Madhu; Wu, Wei; Graf, Frank; Auer, Michael; te Kamp, Lothar

    2014-05-01

    Soil Bioengineering methods are not only effective from an economical point of view, but they are also interesting as fully ecological solutions. The presented project is aimed to define a numerical model which includes the impact of vegetation on slope stability, considering both mechanical and hydrological effects. In this project, a constitutive model has been developed that accounts for the multi-phase nature of the soil, namely the partly saturated condition and it also includes the effects of a biological component. The constitutive equation is implemented in the Finite Element (FE) software Comes-Geo with an implicit integration scheme that accounts for the collapse of the soils structure due to wetting. The mathematical formulation of the constitutive equations is introduced by means of thermodynamics and it simulates the growth of the biological system during the time. The numerical code is then applied in the analysis of an ideal rainfall induced landslide. The slope is analyzed for vegetated and non-vegetated conditions. The final results allow to quantitatively assessing the impact of vegetation on slope stability. This allows drawing conclusions and choosing whenever it is worthful to use soil bioengineering methods in slope stabilization instead of traditional approaches. The application of the FE methods show some advantages with respect to the commonly used limit equilibrium analyses, because it can account for the real coupled strain-diffusion nature of the problem. The mechanical strength of roots is in fact influenced by the stress evolution into the slope. Moreover, FE method does not need a pre-definition of any failure surface. FE method can also be used in monitoring the progressive failure of the soil bio-engineered system as it calculates the amount of displacements and strains of the model slope. The preliminary study results show that the formulated equations can be useful for analysis and evaluation of different soil bio

  10. Computational Analyses of Pressurization in Cryogenic Tanks

    NASA Technical Reports Server (NTRS)

    Ahuja, Vineet; Hosangadi, Ashvin; Lee, Chun P.; Field, Robert E.; Ryan, Harry

    2010-01-01

    A comprehensive numerical framework utilizing multi-element unstructured CFD and rigorous real fluid property routines has been developed to carry out analyses of propellant tank and delivery systems at NASA SSC. Traditionally CFD modeling of pressurization and mixing in cryogenic tanks has been difficult primarily because the fluids in the tank co-exist in different sub-critical and supercritical states with largely varying properties that have to be accurately accounted for in order to predict the correct mixing and phase change between the ullage and the propellant. For example, during tank pressurization under some circumstances, rapid mixing of relatively warm pressurant gas with cryogenic propellant can lead to rapid densification of the gas and loss of pressure in the tank. This phenomenon can cause serious problems during testing because of the resulting decrease in propellant flow rate. With proper physical models implemented, CFD can model the coupling between the propellant and pressurant including heat transfer and phase change effects and accurately capture the complex physics in the evolving flowfields. This holds the promise of allowing the specification of operational conditions and procedures that could minimize the undesirable mixing and heat transfer inherent in propellant tank operation. In our modeling framework, we incorporated two different approaches to real fluids modeling: (a) the first approach is based on the HBMS model developed by Hirschfelder, Beuler, McGee and Sutton and (b) the second approach is based on a cubic equation of state developed by Soave, Redlich and Kwong (SRK). Both approaches cover fluid properties and property variation spanning sub-critical gas and liquid states as well as the supercritical states. Both models were rigorously tested and properties for common fluids such as oxygen, nitrogen, hydrogen etc were compared against NIST data in both the sub-critical as well as supercritical regimes.

  11. Soil grain analyses at Meridiani Planum, Mars

    USGS Publications Warehouse

    Weitz, C.M.; Anderson, R.C.; Bell, J.F.; Farrand, W. H.; Herkenhoff, K. E.; Johnson, J. R.; Jolliff, B.L.; Morris, R.V.; Squyres, S. W.; Sullivan, R.J.

    2006-01-01

    Grain-size analyses of the soils at Meridiani Planum have been used to identify rock souces for the grains and provide information about depositional processes under past and current conditions. Basaltic sand, dust, millimeter-size hematite-rich spherules interpreted as concretions, spherule fragments, coated partially buried spherules, basalt fragments, sedimentary outcrop fragments, and centimeter-size cobbles are concentrated on the upper surfaces of the soils as a lag deposit, while finer basaltic sands and dust dominate the underlying soils. There is a bimodal distribution of soil grain sizes with one population representing grains <125 ??m and the other falling between 1-4.5 mm. Soils within craters like Eagle and Endurance show a much greater diversity of grain morphologies compared to the plains. The spherules found in the plains soils are approximately 1-2 mm smaller in size than those seen embedded in the outcrop rocks of Eagle and Endurance craters. The average major axis for all unfractured spherules measured in the soils and outcrop rocks is 2.87 ?? 1.18 mm, with a trend toward decreasing spherule sizes in both the soils and outcrop rocks as the rover drove southward. Wind ripples seen across the plains of Meridiani are dominated by similar size (1.3-1.7 mm) hematite-rich grains, and they match in size the larger grains on plains ripples at Gusev Crater. Larger clasts and centimeter-size cobbles that are scattered on the soils have several spectral and compositional types, reflecting multiple origins. The cobbles tend to concentrate within ripple troughs along the plains and in association with outcrop exposures. Copyright 2006 by the American Geophysical Union.

  12. Integrated Genomic Analyses in Bronchopulmonary Dysplasia

    PubMed Central

    Ambalavanan, Namasivayam; Cotten, C. Michael; Page, Grier P.; Carlo, Waldemar A.; Murray, Jeffrey C.; Bhattacharya, Soumyaroop; Mariani, Thomas J.; Cuna, Alain C.; Faye-Petersen, Ona M.; Kelly, David; Higgins, Rosemary D.

    2014-01-01

    Objective To identify single nucleotide polymorphisms (SNPs) and pathways associated with bronchopulmonary dysplasia (BPD) because O2 requirement at 36 weeks’ post-menstrual age risk is strongly influenced by heritable factors. Study design A genome-wide scan was conducted on 1.2 million genotyped SNPs, and an additional 7 million imputed SNPs, using a DNA repository of extremely low birth weight infants. Genome-wide association and gene set analysis was performed for BPD or death, severe BPD or death, and severe BPD in survivors. Specific targets were validated using gene expression in BPD lung tissue and in mouse models. Results Of 751 infants analyzed, 428 developed BPD or died. No SNPs achieved genome-wide significance (p<10−8) although multiple SNPs in adenosine deaminase (ADARB2), CD44, and other genes were just below p<10−6. Of approximately 8000 pathways, 75 were significant at False Discovery Rate (FDR) <0.1 and p<0.001 for BPD/death, 95 for severe BPD/death, and 90 for severe BPD in survivors. The pathway with lowest FDR was miR-219 targets (p=1.41E-08, FDR 9.5E-05) for BPD/death and Phosphorous Oxygen Lyase Activity (includes adenylate and guanylate cyclases) for both severe BPD/death (p=5.68E-08, FDR 0.00019) and severe BPD in survivors (p=3.91E-08, FDR 0.00013). Gene expression analysis confirmed significantly increased miR-219 and CD44 in BPD. Conclusions Pathway analyses confirmed involvement of known pathways of lung development and repair (CD44, Phosphorus Oxygen Lyase Activity) and indicated novel molecules and pathways (ADARB2, Targets of miR-219) involved in genetic predisposition to BPD. PMID:25449221

  13. Assessing the reproducibility of discriminant function analyses.

    PubMed

    Andrew, Rose L; Albert, Arianne Y K; Renaut, Sebastien; Rennison, Diana J; Bock, Dan G; Vines, Tim

    2015-01-01

    Data are the foundation of empirical research, yet all too often the datasets underlying published papers are unavailable, incorrect, or poorly curated. This is a serious issue, because future researchers are then unable to validate published results or reuse data to explore new ideas and hypotheses. Even if data files are securely stored and accessible, they must also be accompanied by accurate labels and identifiers. To assess how often problems with metadata or data curation affect the reproducibility of published results, we attempted to reproduce Discriminant Function Analyses (DFAs) from the field of organismal biology. DFA is a commonly used statistical analysis that has changed little since its inception almost eight decades ago, and therefore provides an opportunity to test reproducibility among datasets of varying ages. Out of 100 papers we initially surveyed, fourteen were excluded because they did not present the common types of quantitative result from their DFA or gave insufficient details of their DFA. Of the remaining 86 datasets, there were 15 cases for which we were unable to confidently relate the dataset we received to the one used in the published analysis. The reasons ranged from incomprehensible or absent variable labels, the DFA being performed on an unspecified subset of the data, or the dataset we received being incomplete. We focused on reproducing three common summary statistics from DFAs: the percent variance explained, the percentage correctly assigned and the largest discriminant function coefficient. The reproducibility of the first two was fairly high (20 of 26, and 44 of 60 datasets, respectively), whereas our success rate with the discriminant function coefficients was lower (15 of 26 datasets). When considering all three summary statistics, we were able to completely reproduce 46 (65%) of 71 datasets. While our results show that a majority of studies are reproducible, they highlight the fact that many studies still are not the

  14. Assessing the reproducibility of discriminant function analyses

    PubMed Central

    Andrew, Rose L.; Albert, Arianne Y.K.; Renaut, Sebastien; Rennison, Diana J.; Bock, Dan G.

    2015-01-01

    Data are the foundation of empirical research, yet all too often the datasets underlying published papers are unavailable, incorrect, or poorly curated. This is a serious issue, because future researchers are then unable to validate published results or reuse data to explore new ideas and hypotheses. Even if data files are securely stored and accessible, they must also be accompanied by accurate labels and identifiers. To assess how often problems with metadata or data curation affect the reproducibility of published results, we attempted to reproduce Discriminant Function Analyses (DFAs) from the field of organismal biology. DFA is a commonly used statistical analysis that has changed little since its inception almost eight decades ago, and therefore provides an opportunity to test reproducibility among datasets of varying ages. Out of 100 papers we initially surveyed, fourteen were excluded because they did not present the common types of quantitative result from their DFA or gave insufficient details of their DFA. Of the remaining 86 datasets, there were 15 cases for which we were unable to confidently relate the dataset we received to the one used in the published analysis. The reasons ranged from incomprehensible or absent variable labels, the DFA being performed on an unspecified subset of the data, or the dataset we received being incomplete. We focused on reproducing three common summary statistics from DFAs: the percent variance explained, the percentage correctly assigned and the largest discriminant function coefficient. The reproducibility of the first two was fairly high (20 of 26, and 44 of 60 datasets, respectively), whereas our success rate with the discriminant function coefficients was lower (15 of 26 datasets). When considering all three summary statistics, we were able to completely reproduce 46 (65%) of 71 datasets. While our results show that a majority of studies are reproducible, they highlight the fact that many studies still are not the

  15. Consumption Patterns and Perception Analyses of Hangwa

    PubMed Central

    Kwock, Chang Geun; Lee, Min A; Park, So Hyun

    2012-01-01

    Hangwa is a traditional food, corresponding to the current consumption trend, in need of marketing strategies to extend its consumption. Therefore, the purpose of this study was to analyze consumers’ consumption patterns and perception of Hangwa to increase consumption in the market. A questionnaire was sent to 250 consumers by e-mail from Oct 8∼23, 2009 and the data from 231 persons were analyzed in this study. Statistical, descriptive, paired samples t-test, and importance-performance analyses were conducted using SPSS WIN 17.0. According to the results, Hangwa was purchased mainly ‘for present’ (39.8%) and the main reasons for buying it were ‘traditional image’ (33.3%) and ‘taste’ (22.5%). When importance and performance of attributes considered in purchasing Hangwa were evaluated, performance was assessed to be lower than importance for all attributes. The attributes in the first quadrant with a high importance and a high performance were ‘a sanitary process’, ‘a rigorous quality mark’ and ‘taste’, which were related with quality of the products. In addition, those with a high importance but a low performance were ‘popularization through advertisement’, ‘promotion through mass media’, ‘conversion of thought on traditional foods’, ‘a reasonable price’ and ‘a wide range of price’. In conclusion, Hangwa manufacturers need to diversify products and extend the expiration date based on technologies to promote its consumption. In terms of price, Hangwa should become more available by lowering the price barrier for consumers who are sensitive to price. PMID:24471065

  16. Viscoelastic analyses of launch vehicle components

    SciTech Connect

    Chi, J.K.; Lin, S.R.

    1995-12-31

    Current analysis techniques for solid rocket propellant, and insulation used in space launch vehicles, have several shortcomings. The simplest linear elastic analysis method ignores the inherent viscoelastic behavior of these materials entirely. The relaxation modulus method commonly used to simulate time-dependent effects ignores the past loading history, while the rigorous viscoelastic finite-element analysis is often expensive and impractical. The response of viscoelastic materials is often characterized by the time-dependent relaxation moduli obtained from uniaxial relaxation tests. Since the relaxation moduli are functions of elapsed time, the viscoelastic analysis is not only dependent on the current stress or strain state but also the full loading history. As a preliminary step towards developing a procedure which will yield reasonably conservative results for analyzing the structural response of solid rocket motors, an equivalent-modulus approach was developed. To demonstrate its application, a viscoelastic thick-walled cylindrical material, confined by a stiff steel case and under an internal pressure condition, was analyzed using (1) the equivalent-modulus elastic quasi-static method, (2) an exact viscoelastic closed-form solution, and (3) the viscoelastic finite-element program. A combination of two springs and one viscous damper is used to represent the viscoelastic material with parameters obtained from stress-relaxation tests. The equivalent modulus is derived based on an accumulated quasi-static stress/strain state. The exact closed-form solution is obtained by the Laplace Transform method. The ABAQUS program is then used for the viscoelastic finite-element solution, where the loading-rate dependent moduli is represented by a Prony series expansion of the relaxation modulus. Additional analyses were performed for two space launch solid rocket motors for the purpose of comparing results from the equivalent-modulus approach and the ABAQUS program.

  17. Trend analyses with river sediment rating curves

    USGS Publications Warehouse

    Warrick, Jonathan A.

    2015-01-01

    Sediment rating curves, which are fitted relationships between river discharge (Q) and suspended-sediment concentration (C), are commonly used to assess patterns and trends in river water quality. In many of these studies it is assumed that rating curves have a power-law form (i.e., C = aQb, where a and b are fitted parameters). Two fundamental questions about the utility of these techniques are assessed in this paper: (i) How well to the parameters, a and b, characterize trends in the data? (ii) Are trends in rating curves diagnostic of changes to river water or sediment discharge? As noted in previous research, the offset parameter, a, is not an independent variable for most rivers, but rather strongly dependent on b and Q. Here it is shown that a is a poor metric for trends in the vertical offset of a rating curve, and a new parameter, â, as determined by the discharge-normalized power function [C = â (Q/QGM)b], where QGM is the geometric mean of the Q values sampled, provides a better characterization of trends. However, these techniques must be applied carefully, because curvature in the relationship between log(Q) and log(C), which exists for many rivers, can produce false trends in â and b. Also, it is shown that trends in â and b are not uniquely diagnostic of river water or sediment supply conditions. For example, an increase in â can be caused by an increase in sediment supply, a decrease in water supply, or a combination of these conditions. Large changes in water and sediment supplies can occur without any change in the parameters, â and b. Thus, trend analyses using sediment rating curves must include additional assessments of the time-dependent rates and trends of river water, sediment concentrations, and sediment discharge.

  18. Comparative mutational analyses of influenza A viruses

    PubMed Central

    Cheung, Peter Pak-Hang; Rogozin, Igor B.; Choy, Ka-Tim; Ng, Hoi Yee

    2015-01-01

    The error-prone RNA-dependent RNA polymerase (RdRP) and external selective pressures are the driving forces for RNA viral diversity. When confounded by selective pressures, it is difficult to assess if influenza A viruses (IAV) that have a wide host range possess comparable or distinct spontaneous mutational frequency in their RdRPs. We used in-depth bioinformatics analyses to assess the spontaneous mutational frequencies of two RdRPs derived from human seasonal (A/Wuhan/359/95; Wuhan) and H5N1 (A/Vietnam/1203/04; VN1203) viruses using the mini-genome system with a common firefly luciferase reporter serving as the template. High-fidelity reverse transcriptase was applied to generate high-quality mutational spectra which allowed us to assess and compare the mutational frequencies and mutable motifs along a target sequence of the two RdRPs of two different subtypes. We observed correlated mutational spectra (τ correlation P < 0.0001), comparable mutational frequencies (H3N2:5.8 ± 0.9; H5N1:6.0 ± 0.5), and discovered a highly mutable motif “(A)AAG” for both Wuhan and VN1203 RdRPs. Results were then confirmed with two recombinant A/Puerto Rico/8/34 (PR8) viruses that possess RdRP derived from Wuhan or VN1203 (RG-PR8×WuhanPB2, PB1, PA, NP and RG-PR8×VN1203PB2, PB1, PA, NP). Applying novel bioinformatics analysis on influenza mutational spectra, we provide a platform for a comprehensive analysis of the spontaneous mutation spectra for an RNA virus. PMID:25404565

  19. El Paso Electric photovoltaic-system analyses

    SciTech Connect

    Not Available

    1982-05-01

    Four analyses were performed on the Newman Power Station PV system. Two were performed using the Photovoltaic Transient Analysis Program (PV-TAP) and two with the SOLCEL II code. The first was to determine the optimum tilt angle for the array and the sensitivity of the annual energy production to variation in tilt angle. The optimum tilt angle was found to be 28/sup 0/, and variations of 2/sup 0/ produce losses of only 0.06% in the annual energy production. The second analysis assesses the power loss due to cell-to-cell variations in short circuit current and the degree of improvement attainable by sorting cells and matching modules. Typical distributions on short circuit current can cause losses of about 9.5 to 11 percent in peak array power, and sorting cells into 4 bins prior to module assembly can reduce the losses to about 6 to 8 percent. Using modules from the same cell bins in building series strings can reduce the losses to about 4.5 to 6 percent. Results are nearly the same if the array is operated at a fixed votage. The third study quantifies the magnitude and frequency of occurrence of high cell temperatures due to reverse bias caused by shadowing, and it demonstrates that cell temperatures achieved in reverse bias are higher for cells with larger shunt resistance. The last study assesses the adequacy of transient protection devices on the dc power lines to transients produced by array switching and lightning. Large surge capacitors on the dc power line effectively limit voltage excursions at the array and at the control room due to lightning. Without insertion of series resistors, the current may be limited only by cable and switch impedances, and all elements could be severely stressed. (LEW)

  20. SEDS Tether M/OD Damage Analyses

    NASA Technical Reports Server (NTRS)

    Hayashida, K. B.; Robinson, J. H.; Hill, S. A.

    1997-01-01

    The Small Expendable Deployer System (SEDS) was designed to deploy an endmass at the end of a 20-km-long tether which acts as an upper stage rocket, and the threats from the meteoroid and orbital debris (M/OD) particle environments on SEDS components are important issues for the safety and success of any SEDS mission. However, the possibility of severing the tether due to M/OD particle impacts is an even more serious concern, since the SEDS tether has a relatively large exposed area to the M/OD environments although its diameter is quite small. The threats from the M/OD environments became a very important issue for the third SEDS mission, since the project office proposed using the shuttle orbiter as a launch platform instead of the second stage of a Delta II expendable rocket, which was used for the first two SEDS missions. A series of hyper-velocity impact tests were performed at the Johnson Space Center and Arnold Engineering Development Center to help determine the critical particle sizes required to sever the tether. The computer hydrodynamic code or hydrocode called CTH, developed by the Sandia National Laboratories, was also used to simulate the damage on the SEDS tether caused by both the orbital debris and test particle impacts. The CTH hydrocode simulation results provided the much needed information to help determine the critical particle sizes required to sever the tether. The M/OD particle sizes required to sever the tether were estimated to be less than 0.1 cm in diameter from these studies, and these size particles are more abundant in low-Earth orbit than larger size particles. Finally, the authors performed the M/OD damage analyses for the three SEDS missions; i.e., SEDS-1, -2, and -3 missions, by using the information obtained from the hypervelocity impact test and hydrocode simulations results.

  1. PCR und ELISA - Alternativen zum Maustest für die Analyse des Botulismus-Neurotoxin-C1 Giftbildungspotentiales in Umweltproben? [PCR and ELISA - in vitro alternatives to the mouse-bioassay for assessing the botulinum-neurotoxin-C1 production potential in environmental samples?

    USGS Publications Warehouse

    Zechmeister, T.C.; Farnleitner, A.H.; Rocke, T.E.; Pittner, F.; Rosengarten, R.; Mach, R.L.; Herzig, A.; Kirschner, A.K.T.

    2002-01-01

    Botulism is one of the most important bird diseases world-wide and is caused by the intoxication with Botulinum-Neurotoxin-C1 (BoNt-C1), which is produced by toxigenic clostridia under appropriate conditions. Avian botulism leads regularly to large losses among the migrating bird populations breeding and resting at the saltwater pools of the Austrian national park Neusiedler See-Seewinkel. Despite of its ethical dubiousness and its high technical expense the mouse-bioassay is still used as the routine standard method for the detection of BoNt-C1. According to the 3R-concept, in vitro alternative methods for the qualitative detection of BoNt-C1 (immunostick-ELISA) and a corresponding BoNt-C1 gene fragment (nested-PCR) were established. In order to estimate the BoNt-C1 production potential the methods were tested with sediment samples from different saltwater pools subjected to cultivation conditions appropriate for in vitro BoNt-C1-production. With the mouse-bioassay, 52 out of 77 samples were found to have a positive toxin production potential. The immunostick-ELISA showed a similar sensitivity as the mouse-bioassay and exhibited a highly significant positive correlation (r=0.94; p<0.001) with the mouse-bioassay in detecting BoNt-C1. The nested-PCR approach revealed higher numbers of positive BoNt-C1 gene fragment detections as compared to the direct toxin analysis approaches. A weak correlation (r=0.21; p=0.07) with the mouse-bioassay was discernible, no correlation was found with the immunostick-ELISA (r=0.09; p=0.46). Obviously, the PCR approach detected the BoNt-C1 gene fragment in some of the samples where no toxin expression has occurred. Thus it is suggested that the qualitative immunostick-ELISA represents a potential in vitro alternative to the mouse-bioassay for assessing the BoNt-C1 production potential in environmental samples. In contrast, qualitative BoNt-C1 gene fragment detection via PCR led to an overestimation of the actual toxin production potential.

  2. Genome-Facilitated Analyses of Geomicrobial Processes

    SciTech Connect

    Kenneth H. Nealson

    2012-05-02

    that makes up chitin, virtually all of the strains were in fact capable. This led to the discovery of a great many new genes involved with chitin and NAG metabolism (7). In a similar vein, a detailed study of the sugar utilization pathway revealed a major new insight into the regulation of sugar metabolism in this genus (19). Systems Biology and Comparative Genomics of the shewanellae: Several publications were put together describing the use of comparative genomics for analyses of the group Shewanella, and these were a logical culmination of our genomic-driven research (10,15,18). Eight graduate students received their Ph.D. degrees doing part of the work described here, and four postdoctoral fellows were supported. In addition, approximately 20 undergraduates took part in projects during the grant period.

  3. Static and dynamic analyses of tensegrity structures

    NASA Astrophysics Data System (ADS)

    Nishimura, Yoshitaka

    Tensegrity structures are a class of truss structures consisting of a continuous set of tension members (cables) and a discrete set of compression members (bars). Since tensegrity structures are light weight and can be compactly stowed and deployed, cylindrical tensegrity modules have been proposed for space structures. From a view point of structural dynamics, tensegrity structures pose a new set of problems, i.e., initial shape finding. Initial configurations of tensegrity structures must be computed by imposing a pre-stressability condition to initial equilibrium equations. There are ample qualitative statements regarding the initial geometry of cylindrical and spherical tensegrity modules. Quantitative initial shape anlyses have only been performed on one-stage and two-stage cylindrical modules. However, analytical expressions for important geometrical parameters such as twist angles and overlap ratios lack the definition of the initial shape of both cylindrical and spherical tensegrity modules. In response to the above needs, a set of static and dynamic characterization procedures for tensegrity modules was first developed. The procedures were subsequently applied to Buckminster Fuller's spherical tensegrity modules. Both the initial shape and the corresponding pre-stress mode were analytically obtained by using the graphs of the tetrahedral, octahedral (cubic), and icosahedral (dodecahedral) groups. For pre-stressed configurations, modal analyses were conducted to classify a large number of infinitesimal mechanism modes. The procedures also applied tocyclic cylindrical tensegrity modules with an arbitrary number of stages. It was found that both the Maxwell number and the number of infinitesimal mechanism modes are independent of the number of stages in the axial direction. A reduced set of equilibrium equations was derived by incorporating cyclic symmetry and the flip, or quasi-flip, symmetry of the cylindrical modules. For multi-stage modules with more than

  4. First Super-Earth Atmosphere Analysed

    NASA Astrophysics Data System (ADS)

    2010-12-01

    The atmosphere around a super-Earth exoplanet has been analysed for the first time by an international team of astronomers using ESO's Very Large Telescope. The planet, which is known as GJ 1214b, was studied as it passed in front of its parent star and some of the starlight passed through the planet's atmosphere. We now know that the atmosphere is either mostly water in the form of steam or is dominated by thick clouds or hazes. The results will appear in the 2 December 2010 issue of the journal Nature. The planet GJ 1214b was confirmed in 2009 using the HARPS instrument on ESO's 3.6-metre telescope in Chile (eso0950) [1]. Initial findings suggested that this planet had an atmosphere, which has now been confirmed and studied in detail by an international team of astronomers, led by Jacob Bean (Harvard-Smithsonian Center for Astrophysics), using the FORS instrument on ESO's Very Large Telescope. "This is the first super-Earth to have its atmosphere analysed. We've reached a real milestone on the road toward characterising these worlds," said Bean. GJ 1214b has a radius of about 2.6 times that of the Earth and is about 6.5 times as massive, putting it squarely into the class of exoplanets known as super-Earths. Its host star lies about 40 light-years from Earth in the constellation of Ophiuchus (the Serpent Bearer). It is a faint star [2], but it is also small, which means that the size of the planet is large compared to the stellar disc, making it relatively easy to study [3]. The planet travels across the disc of its parent star once every 38 hours as it orbits at a distance of only two million kilometres: about seventy times closer than the Earth orbits the Sun. To study the atmosphere, the team observed the light coming from the star as the planet passed in front of it [4]. During these transits, some of the starlight passes through the planet's atmosphere and, depending on the chemical composition and weather on the planet, specific wavelengths of light are

  5. Residual Strength Analyses of Monolithic Structures

    NASA Technical Reports Server (NTRS)

    Forth, Scott (Technical Monitor); Ambur, Damodar R. (Technical Monitor); Seshadri, B. R.; Tiwari, S. N.

    2003-01-01

    Finite-element fracture simulation methodology predicts the residual strength of damaged aircraft structures. The methodology uses the critical crack-tip-opening-angle (CTOA) fracture criterion to characterize the fracture behavior of the material. The CTOA fracture criterion assumes that stable crack growth occurs when the crack-tip angle reaches a constant critical value. The use of the CTOA criterion requires an elastic- plastic, finite-element analysis. The critical CTOA value is determined by simulating fracture behavior in laboratory specimens, such as a compact specimen, to obtain the angle that best fits the observed test behavior. The critical CTOA value appears to be independent of loading, crack length, and in-plane dimensions. However, it is a function of material thickness and local crack-front constraint. Modeling the local constraint requires either a three-dimensional analysis or a two-dimensional analysis with an approximation to account for the constraint effects. In recent times as the aircraft industry is leaning towards monolithic structures with the intention of reducing part count and manufacturing cost, there has been a consistent effort at NASA Langley to extend critical CTOA based numerical methodology in the analysis of integrally-stiffened panels.In this regard, a series of fracture tests were conducted on both flat and curved aluminum alloy integrally-stiffened panels. These flat panels were subjected to uniaxial tension and during the test, applied load-crack extension, out-of-plane displacements and local deformations around the crack tip region were measured. Compact and middle-crack tension specimens were tested to determine the critical angle (wc) using three-dimensional code (ZIP3D) and the plane-strain core height (hJ using two-dimensional code (STAGS). These values were then used in the STAGS analysis to predict the fracture behavior of the integrally-stiffened panels. The analyses modeled stable tearing, buckling, and crack

  6. Runtime and Pressurization Analyses of Propellant Tanks

    NASA Technical Reports Server (NTRS)

    Field, Robert E.; Ryan, Harry M.; Ahuja, Vineet; Hosangadi, Ashvin; Lee, Chung P.

    2007-01-01

    Multi-element unstructured CFD has been utilized at NASA SSC to carry out analyses of propellant tank systems in different modes of operation. The three regimes of interest at SSC include (a) tank chill down (b) tank pressurization and (c) runtime propellant draw-down and purge. While tank chill down is an important event that is best addressed with long time-scale heat transfer calculations, CFD can play a critical role in the tank pressurization and runtime modes of operation. In these situations, problems with contamination of the propellant by inclusion of the pressurant gas from the ullage causes a deterioration of the quality of the propellant delivered to the test article. CFD can be used to help quantify the mixing and propellant degradation. During tank pressurization under some circumstances, rapid mixing of relatively warm pressurant gas with cryogenic propellant can lead to rapid densification of the gas and loss of pressure in the tank. This phenomenon can cause serious problems during testing because of the resulting decrease in propellant flow rate. With proper physical models implemented, CFD can model the coupling between the propellant and pressurant including heat transfer and phase change effects and accurately capture the complex physics in the evolving flowfields. This holds the promise of allowing the specification of operational conditions and procedures that could minimize the undesirable mixing and heat transfer inherent in propellant tank operation. It should be noted that traditional CFD modeling is inadequate for such simulations because the fluids in the tank are in a range of different sub-critical and supercritical states and elaborate phase change and mixing rules have to be developed to accurately model the interaction between the ullage gas and the propellant. We show a typical run-time simulation of a spherical propellant tank, containing RP-1 in this case, being pressurized with room-temperature nitrogen at 540 R. Nitrogen

  7. Descriptive and Experimental Analyses of Potential Precursors to Problem Behavior

    ERIC Educational Resources Information Center

    Borrero, Carrie S. W.; Borrero, John C.

    2008-01-01

    We conducted descriptive observations of severe problem behavior for 2 individuals with autism to identify precursors to problem behavior. Several comparative probability analyses were conducted in addition to lag-sequential analyses using the descriptive data. Results of the descriptive analyses showed that the probability of the potential…

  8. Non-destructive infrared analyses: a method for provenance analyses of sandstones

    NASA Astrophysics Data System (ADS)

    Bowitz, Jörg; Ehling, Angela

    2008-12-01

    Infrared spectroscopy (IR spectroscopy) is commonly applied in the laboratory for mineral analyses in addition to XRD. Because such technical efforts are time and cost consuming, we present an infrared-based mobile method for non-destructive mineral and provenance analyses of sandstones. IR spectroscopy is based on activating chemical bonds. By irradiating a mineral mixture, special bonds are activated to vibrate depending on the bond energy (resonance vibration). Accordingly, the energy of the IR spectrum will be reduced thereby generating an absorption spectrum. The positions of the absorption maxima within the spectral region indicate the type of the bonds and in many cases identify minerals containing these bonds. The non-destructive reflection spectroscopy operates in the near infrared region (NIR) and can detect all common clay minerals as well as sulfates, hydroxides and carbonates. The spectra produced have been interpreted by computer using digital mineral libraries that have been especially collected for sandstones. The comparison of all results with XRD, RFA and interpretations of thin sections demonstrates impressively the accuracy and reliability of this method. Not only are different minerals detectable, but also differently ordered kaolinites and varieties of illites can be identified by the shape and size of the absorption bands. Especially clay minerals and their varieties in combination with their relative contents form the characteristic spectra of sandstones. Other components such as limonite, hematite and amorphous silica also influence the spectra. Sandstones, similar in colour and texture, often can be identified by their characteristic reflectance spectra. Reference libraries with more than 60 spectra of important German sandstones have been created to enable entirely computerized interpretations and identifications of these dimension stones. The analysis of infrared spectroscopy results is demonstrated with examples of different sandstones

  9. Using a Log Analyser to Assist Research into Haptic Technology

    NASA Astrophysics Data System (ADS)

    Jónsson, Fannar Freyr; Hvannberg, Ebba Þóra

    Usability evaluations collect subjective and objective measures. Examples of the latter are time to complete a task. The paper describes use cases of a log analyser for haptic feedback. The log analyser reads a log file and extracts information such as time of each practice and assessment session, analyses whether the user goes off curve and measures the force applied. A study case using the analyser is performed using a PHANToM haptic learning environment application that is used to teach young visually impaired students the subject of polynomials. The paper answers six questions to illustrate further use cases of the log analyser.

  10. Integrated Waste Treatment Unit (IWTU) Input Coal Analyses and Off-Gass Filter (OGF) Content Analyses

    SciTech Connect

    Jantzen, Carol M.; Missimer, David M.; Guenther, Chris P.; Shekhawat, Dushyant; VanEssendelft, Dirk T.; Means, Nicholas C.

    2015-04-23

    in process piping and materials, in excessive off-gas absorbent loading, and in undesired process emissions. The ash content of the coal is important as the ash adds to the DMR and other vessel products which affect the final waste product mass and composition. The amount and composition of the ash also affects the reaction kinetics. Thus ash content and composition contributes to the mass balance. In addition, sodium, potassium, calcium, sulfur, and maybe silica and alumina in the ash may contribute to wall-scale formation. Sodium, potassium, and alumina in the ash will be overwhelmed by the sodium, potassium, and alumina from the feed but the impact from the other ash components needs to be quantified. A maximum coal particle size is specified so the feed system does not plug and a minimum particle size is specified to prevent excess elutriation from the DMR to the Process Gas Filter (PGF). A vendor specification was used to procure the calcined coal for IWTU processing. While the vendor supplied a composite analysis for the 22 tons of coal (Appendix A), this study compares independent analyses of the coal performed at the Savannah River National Laboratory (SRNL) and at the National Energy Technology Laboratory (NETL). Three supersacks a were sampled at three different heights within the sack in order to determine within bag variability and between bag variability of the coal. These analyses were also compared to the vendor’s composite analyses and to the coal specification. These analyses were also compared to historic data on Bestac coal analyses that had been performed at Hazen Research Inc. (HRI) between 2004-2011.

  11. The relationship among sea surface roughness variations, oceanographic analyses, and airborne remote sensing analyses

    NASA Technical Reports Server (NTRS)

    Oertel, G. F.; Wade, T. L.

    1981-01-01

    The synthetic aperture radar (SAR) was studied to determine whether it could image large scale estuaries and oceanic features such as fronts and to explain the electromagnetic interaction between SAR and the individual surface front features. Fronts were observed to occur at the entrance to the Chesapeake Bay. The airborne measurements consisted of data collection by SAR onboard an F-4 aircraft and real aperture side looking radar (SLAR) in Mohawk aircraft. A total of 89 transects were flown. Surface roughness and color as well as temperature and salinity were evaluated. Cross-frontal surveys were made. Frontal shear and convergence flow were obtained. Surface active organic materials, it was indicated, are present at the air-sea interface. In all, 2000 analyses were conducted to characterize the spatial and temporal variabilities associated with water mass boundaries.

  12. Molekulare Methoden zum Nachweis, zur Quantifizierung und zum Monitoring der Mykotoxinbildung lebensmittelrelevanter Pilze

    NASA Astrophysics Data System (ADS)

    Geisen, Rolf

    Schimmelpilze kommen ubiquitär vor und spielen besonders bei pflanzlichen Lebensmitteln und Rohprodukten eine besondere Rolle als Verderbsorganismen. Es wird geschätzt, dass 20-25 % der jährlichen Produktion an pflanzlichen Produkten durch Schimmelpilze verdorben werden (Smith et al., 1994). Viele der lebensmittelrelevanten Schimmelpilze sind zudem in der Lage, Mykotoxine, toxische Sekundärmetabolite, zu bilden, was das Ausmaß des Problems deutlich macht. Die wichtigsten mykotoxinbildenden Spezies gehören zu den Fusarien (Trichothecene, Fumonisine, Zearalenon), Aspergillen (Aflatoxin, Ochratoxin, Cyclopiazonsäure) und Penicillien (Patulin, Ochratoxin). Für viele Mykotoxine, wie die Aflatoxine, Ochratoxin, Fumonisine und Trichothecene sind Grenzwerte erlassen worden, die die Verkehrsfähigkeit betroffener Produkte regeln. Die Einhaltung der Grenzwerte kann sehr genau durch offizielle chemisch-analytische Methoden, wie HPLC, GC-MS etc. kontrolliert werden. Diese analytischen Methoden sind aber für die Anwendung eines HACCP-Ansatzes zur Kontrolle der Mykotoxinbildung nur bedingt geeignet, da sie Endpunktkontrollen darstellen und nur das über eine längere Zeit gebildete Mykotoxin bestimmen. Sie sagen daher nichts über die biologischen Bedingungen zur Zeit der Bildung durch den Pilz aus.

  13. Methods and Procedures for Shielding Analyses for the SNS

    SciTech Connect

    Gallmeier, Franz X.; Iverson, Erik B.; Remec, Igor; Lu, Wei; Popova, Irina

    2014-01-01

    In order to provide radiologically safe Spallation Neutron Source operation, shielding analyses are performed according to Oak Ridge National Laboratory internal regulations and to comply with the Code of Federal Regulations. An overview of on-going shielding work for the accelerator facility and neutrons beam lines, methods, used for the analyses, and associated procedures and regulations is presented. Methods used to perform shielding analyses are described as well.

  14. SENSITIVITY ANALYSIS FOR SALTSTONE DISPOSAL UNIT COLUMN DEGRADATION ANALYSES

    SciTech Connect

    Flach, G.

    2014-10-28

    PORFLOW related analyses supporting a Sensitivity Analysis for Saltstone Disposal Unit (SDU) column degradation were performed. Previous analyses, Flach and Taylor 2014, used a model in which the SDU columns degraded in a piecewise manner from the top and bottom simultaneously. The current analyses employs a model in which all pieces of the column degrade at the same time. Information was extracted from the analyses which may be useful in determining the distribution of Tc-99 in the various SDUs throughout time and in determining flow balances for the SDUs.

  15. Analysing harmonic motions with an iPhone’s magnetometer

    NASA Astrophysics Data System (ADS)

    Yavuz, Ahmet; Kağan Temiz, Burak

    2016-05-01

    In this paper, we propose an experiment for analysing harmonic motion using an iPhone’s (or iPad’s) magnetometer. This experiment consists of the detection of magnetic field variations obtained from an iPhone’s magnetometer sensor. A graph of harmonic motion is directly displayed on the iPhone’s screen using the Sensor Kinetics application. Data from this application was analysed with Eureqa software to establish the equation of the harmonic motion. Analyses show that the use of an iPhone’s magnetometer to analyse harmonic motion is a practical and effective method for small oscillations and frequencies less than 15-20 Hz.

  16. Tracing Success: Graphical Methods for Analysing Successful Collaborative Problem Solving

    ERIC Educational Resources Information Center

    Joiner, Richard; Issroff, Kim

    2003-01-01

    The aim of this paper is to evaluate the use of trace diagrams for analysing collaborative problem solving. The paper describes a study where trace diagrams were used to analyse joint navigation in a virtual environment. Ten pairs of undergraduates worked together on a distributed virtual task to collect five flowers using two bees with each…

  17. Training Residential Staff to Conduct Trial-Based Functional Analyses

    ERIC Educational Resources Information Center

    Lambert, Joseph M.; Bloom, Sarah E.; Kunnavatana, S. Shanun; Collins, Shawnee D.; Clay, Casey J.

    2013-01-01

    We taught 6 supervisors of a residential service provider for adults with developmental disabilities to train 9 house managers to conduct trial-based functional analyses. Effects of the training were evaluated with a nonconcurrent multiple baseline. Results suggest that house managers can be trained to conduct trial-based functional analyses with…

  18. 41 CFR 101-27.208 - Inventory analyses.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Inventory analyses. 101...-Management of Shelf-Life Materials § 101-27.208 Inventory analyses. (a) An inventory analysis shall be... the established shelf-life period. If the analysis indicates there are quantities which will not...

  19. 41 CFR 101-27.208 - Inventory analyses.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 2 2013-07-01 2012-07-01 true Inventory analyses. 101...-Management of Shelf-Life Materials § 101-27.208 Inventory analyses. (a) An inventory analysis shall be... the established shelf-life period. If the analysis indicates there are quantities which will not...

  20. 41 CFR 101-27.208 - Inventory analyses.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 2 2012-07-01 2012-07-01 false Inventory analyses. 101...-Management of Shelf-Life Materials § 101-27.208 Inventory analyses. (a) An inventory analysis shall be... the established shelf-life period. If the analysis indicates there are quantities which will not...

  1. 41 CFR 101-27.208 - Inventory analyses.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 41 Public Contracts and Property Management 2 2014-07-01 2012-07-01 true Inventory analyses. 101...-Management of Shelf-Life Materials § 101-27.208 Inventory analyses. (a) An inventory analysis shall be... the established shelf-life period. If the analysis indicates there are quantities which will not...

  2. 41 CFR 101-27.208 - Inventory analyses.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 41 Public Contracts and Property Management 2 2011-07-01 2007-07-01 true Inventory analyses. 101...-Management of Shelf-Life Materials § 101-27.208 Inventory analyses. (a) An inventory analysis shall be... the established shelf-life period. If the analysis indicates there are quantities which will not...

  3. 44 CFR 1.9 - Regulatory impact analyses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 44 Emergency Management and Assistance 1 2011-10-01 2011-10-01 false Regulatory impact analyses. 1... HOMELAND SECURITY GENERAL RULEMAKING; POLICY AND PROCEDURES General § 1.9 Regulatory impact analyses. (a) FEMA shall, in connection with any major rule, prepare and consider a Regulatory Impact Analysis....

  4. 9 CFR 590.580 - Laboratory tests and analyses.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Laboratory tests and analyses. 590.580... EGG PRODUCTS INSPECTION INSPECTION OF EGGS AND EGG PRODUCTS (EGG PRODUCTS INSPECTION ACT) Laboratory § 590.580 Laboratory tests and analyses. The official plant, at their expense, shall make tests...

  5. 9 CFR 590.580 - Laboratory tests and analyses.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Laboratory tests and analyses. 590.580... EGG PRODUCTS INSPECTION INSPECTION OF EGGS AND EGG PRODUCTS (EGG PRODUCTS INSPECTION ACT) Laboratory § 590.580 Laboratory tests and analyses. The official plant, at their expense, shall make tests...

  6. 9 CFR 590.580 - Laboratory tests and analyses.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Laboratory tests and analyses. 590.580... EGG PRODUCTS INSPECTION INSPECTION OF EGGS AND EGG PRODUCTS (EGG PRODUCTS INSPECTION ACT) Laboratory § 590.580 Laboratory tests and analyses. The official plant, at their expense, shall make tests...

  7. 9 CFR 590.580 - Laboratory tests and analyses.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Laboratory tests and analyses. 590.580... EGG PRODUCTS INSPECTION INSPECTION OF EGGS AND EGG PRODUCTS (EGG PRODUCTS INSPECTION ACT) Laboratory § 590.580 Laboratory tests and analyses. The official plant, at their expense, shall make tests...

  8. 43 CFR 46.130 - Mitigation measures in analyses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Mitigation measures in analyses. 46.130... Mitigation measures in analyses. (a) Bureau proposed action. The analysis of the proposed action and any... of the effects of any appropriate mitigation measures or best management practices that...

  9. 43 CFR 46.130 - Mitigation measures in analyses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Mitigation measures in analyses. 46.130... Mitigation measures in analyses. (a) Bureau proposed action. The analysis of the proposed action and any... of the effects of any appropriate mitigation measures or best management practices that...

  10. 43 CFR 46.130 - Mitigation measures in analyses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Mitigation measures in analyses. 46.130... Mitigation measures in analyses. (a) Bureau proposed action. The analysis of the proposed action and any... of the effects of any appropriate mitigation measures or best management practices that...

  11. 43 CFR 46.130 - Mitigation measures in analyses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Mitigation measures in analyses. 46.130... Mitigation measures in analyses. (a) Bureau proposed action. The analysis of the proposed action and any... of the effects of any appropriate mitigation measures or best management practices that...

  12. 43 CFR 46.130 - Mitigation measures in analyses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Mitigation measures in analyses. 46.130... Mitigation measures in analyses. (a) Bureau proposed action. The analysis of the proposed action and any... of the effects of any appropriate mitigation measures or best management practices that...

  13. Rational Analyses of Information Foraging on the Web

    ERIC Educational Resources Information Center

    Pirolli, Peter

    2005-01-01

    This article describes rational analyses and cognitive models of Web users developed within information foraging theory. This is done by following the rational analysis methodology of (a) characterizing the problems posed by the environment, (b) developing rational analyses of behavioral solutions to those problems, and (c) developing cognitive…

  14. What can we do about exploratory analyses in clinical trials?

    PubMed

    Moyé, Lem

    2015-11-01

    The research community has alternatively embraced then repudiated exploratory analyses since the inception of clinical trials in the middle of the twentieth century. After a series of important but ultimately unreproducible findings, these non-prospectively declared evaluations were relegated to hypothesis generating. Since the majority of evaluations conducted in clinical trials with their rich data sets are exploratory, the absence of their persuasive power adds to the inefficiency of clinical trial analyses in an atmosphere of fiscal frugality. However, the principle argument against exploratory analyses is not based in statistical theory, but pragmatism and observation. The absence of any theoretical treatment of exploratory analyses postpones the day when their statistical weaknesses might be repaired. Here, we introduce examination of the characteristics of exploratory analyses from a probabilistic and statistical framework. Setting the obvious logistical concerns aside (i.e., the absence of planning produces poor precision), exploratory analyses do not appear to suffer from estimation theory weaknesses. The problem appears to be a difficulty in what is actually reported as the p-value. The use of Bayes Theorem provides p-values that are more in line with confirmatory analyses. This development may inaugurate a body of work that would lead to the readmission of exploratory analyses to a position of persuasive power in clinical trials.

  15. Analyses of Response-Stimulus Sequences in Descriptive Observations

    ERIC Educational Resources Information Center

    Samaha, Andrew L.; Vollmer, Timothy R.; Borrero, Carrie; Sloman, Kimberly; Pipkin, Claire St. Peter; Bourret, Jason

    2009-01-01

    Descriptive observations were conducted to record problem behavior displayed by participants and to record antecedents and consequences delivered by caregivers. Next, functional analyses were conducted to identify reinforcers for problem behavior. Then, using data from the descriptive observations, lag-sequential analyses were conducted to examine…

  16. Descriptive Analyses of Pediatric Food Refusal and Acceptance

    ERIC Educational Resources Information Center

    Borrero, Carrie S. W.; Woods, Julia N.; Borrero, John C.; Masler, Elizabeth A.; Lesser, Aaron D.

    2010-01-01

    Functional analyses of inappropriate mealtime behavior typically include conditions to determine if the contingent delivery of attention, tangible items, or escape reinforce food refusal. In the current investigation, descriptive analyses were conducted for 25 children who had been admitted to a program for the assessment and treatment of food…

  17. 46 CFR Appendix B to Part 154 - Stress Analyses Definitions

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Stress Analyses Definitions B Appendix B to Part 154...—Stress Analyses Definitions The following are the standard definitions of stresses for the analysis of an independent tank type B: Normal stress means the component of stress normal to the plane of...

  18. 46 CFR Appendix B to Part 154 - Stress Analyses Definitions

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Stress Analyses Definitions B Appendix B to Part 154...—Stress Analyses Definitions The following are the standard definitions of stresses for the analysis of an independent tank type B: Normal stress means the component of stress normal to the plane of...

  19. 46 CFR Appendix B to Part 154 - Stress Analyses Definitions

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Stress Analyses Definitions B Appendix B to Part 154...—Stress Analyses Definitions The following are the standard definitions of stresses for the analysis of an independent tank type B: Normal stress means the component of stress normal to the plane of...

  20. 46 CFR Appendix B to Part 154 - Stress Analyses Definitions

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Stress Analyses Definitions B Appendix B to Part 154...—Stress Analyses Definitions The following are the standard definitions of stresses for the analysis of an independent tank type B: Normal stress means the component of stress normal to the plane of...

  1. 46 CFR Appendix B to Part 154 - Stress Analyses Definitions

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Stress Analyses Definitions B Appendix B to Part 154...—Stress Analyses Definitions The following are the standard definitions of stresses for the analysis of an independent tank type B: Normal stress means the component of stress normal to the plane of...

  2. Carrier tracking by smoothing filter can improve symbol SNR

    NASA Technical Reports Server (NTRS)

    Hurd, W. J.; Pomalaza-Raez, C. A.

    1985-01-01

    The potential benefit of using a smoothing filter to estimate carrier phase over use of phase locked loops (PLL) is determined. Numerical results are presented for the performance of three possible configurations of the deep space network advanced receiver. These are residual carrier PLL, sideband aided residual carrier PLL, and finally sideband aiding with a Kalman smoother. The average symbol signal to noise ratio (CNR) after losses due to carrier phase estimation error is computed for different total power SNRs, symbol rates and symbol SNRs. It is found that smoothing is most beneficial for low symbol SNRs and low symbol rates. Smoothing gains up to 0.4 dB over a sideband aided residual carrier PLL, and the combined benefit of smoothing and sideband aiding relative to a residual carrier loop is often in excess of 1 dB.

  3. Iterative deconvolution of x ray and optical SNR images

    NASA Technical Reports Server (NTRS)

    Nisenson, Peter; Standley, Clive; Hughes, John

    1992-01-01

    Blind Iterative Deconvolution (BID) is a technique which was originally developed to correct the degrading effects of atmospheric turbulence on astronomical images from single short exposure, high signal-to-noise-ratio frames. At the Center for Astro physics, we have implemented a version of BID following the general approach of Ayers and Dainty (1988), but extending the technique to use Wiener filtering, and developed it for application to high energy images from Einstein and ROSAT. In the optical, the point spread function (PSF) that degrades the images is due to a combination of telescope and atmospheric aberrations. At high energies, the degrading function is the instrument response function, which is known to be time and energy level unstable. In both cases, the PSF is poorly known, so BID can be used to extract the PSF from the image and then deconvolve the blurred image to produce a sharpened image. Other aspects of this technique are discussed.

  4. The X-ray evolution of SNR 1987A

    NASA Astrophysics Data System (ADS)

    Burrows, David N.; Frank, Kari A.; Park, Sangwook; McCray, Richard; Zhekov, Svetozar

    2016-06-01

    Due to its age and close proximity, the remnant of SN 1987A is the only supernova remnant in which we can study the early developmental stages in detail, providing insight into stellar evolution, the mechanisms of the supernova explosion, and the transition from supernova to supernova remnant as the debris begins to interact with the surrounding circumstellar medium (CSM). We present the latest results from 16 years of Chandra ACIS observations of SN 1987A, now covering 4600‑10600 days after the supernova. At approximately day 7500, the east-west asymmetry of the ring began to reverse, while the soft X-ray light curve switched from an exponential increase to a linear brightening. Since day 9700 the soft X-ray light curve has flattened and remained approximately constant at about 8×10^(12) ergs/cm^2/s, evidence that the blast wave has now left the dense material of the known equatorial ring and is beginning to probe the unknown territory beyond.

  5. X-ray Polarization Probes of SNR and PWN

    NASA Astrophysics Data System (ADS)

    Romani, Roger W.

    2016-04-01

    X-ray synchrotron radiation traces the high energy extrema of e+/e- accelerated by pulsar magnetospheres and supernova shocks. X-ray polarization lets us probe the unresolved geometry of these relativistic shock structures. I summarize what we know about magnetic field geometries in these nebulae and the prospects for learning more from X-ray polarimetry.

  6. Kinetic Simulations of SNR Shocks- Prospects for Particle Acceleration

    NASA Astrophysics Data System (ADS)

    Chapman, Sandra

    2006-02-01

    Recent kinetic simulations of supercritical, quasi-perpendicular shocksyield time varying shock solutions that cyclically reform on thespatio-temporal scales of the incoming protons. Whether a shock solution isstationary or reforming depends upon the plasma parameters which, for SNRshocks are ill defined but believed to be within thetime-dependent regime. We will first review the structure and evolution ofthe time dependentsolutions, and the acceleration processes of the ions and electrons inthese time dependent fields, for a proton-electron plasma. We will thenpresent recent results for a three component plasma: backgroundprotons; electrons; and a second heavier ion population. These accelerationmechanisms may generate a suprathermalïnjection$quot; population - a seed population for subsequentacceleration at the shock, which can in turn generate particles at cosmicray energies.

  7. Assessments of feline plasma biochemistry reference intervals for three in-house analysers and a commercial laboratory analyser.

    PubMed

    Baral, Randolph M; Dhand, Navneet K; Krockenberger, Mark B; Govendir, Merran

    2015-08-01

    For each species, the manufacturers of in-house analysers (and commercial laboratories) provide standard reference intervals (RIs) that do not account for any differences such as geographical population differences and do not overtly state the potential for variation between results obtained from serum or plasma. Additionally, biases have been demonstrated for in-house analysers which result in different RIs for each different type of analyser. The objective of this study was to calculate RIs (with 90% confidence intervals [CIs]) for 13 biochemistry analytes when tested on three commonly used in-house veterinary analysers, as well as a commercial laboratory analyser. The calculated RIs were then compared with those provided by the in-house analyser manufacturers and the commercial laboratory. Plasma samples were collected from 53 clinically normal cats. After centrifugation, plasma was divided into four aliquots; one aliquot was sent to the commercial laboratory and the remaining three were tested using the in-house biochemistry analysers. The distribution of results was used to choose the appropriate statistical technique for each analyte from each analyser to calculate RIs. Provided reference limits were deemed appropriate if they fell within the 90% CIs of the calculated reference limits. Transference validation was performed on provided and calculated RIs. Twenty-nine of a possible 102 provided reference limits (28%) were within the calculated 90% CIs. To ensure proper interpretation of laboratory results, practitioners should determine RIs for their practice populations and/or use reference change values when assessing their patients' clinical chemistry results.

  8. 25 CFR 162.521 - May a lessee incorporate its WEEL analyses into its WSR lease analyses?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false May a lessee incorporate its WEEL analyses into its WSR lease analyses? 162.521 Section 162.521 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER LEASES AND PERMITS Wind and Solar Resource Leases Weels § 162.521 May a...

  9. 25 CFR 162.521 - May a lessee incorporate its WEEL analyses into its WSR lease analyses?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false May a lessee incorporate its WEEL analyses into its WSR lease analyses? 162.521 Section 162.521 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER LEASES AND PERMITS Wind and Solar Resource Leases Weels § 162.521 May a...

  10. Shielding Analyses for VISION Beam Line at SNS

    SciTech Connect

    Popova, Irina; Gallmeier, Franz X

    2014-01-01

    Full-scale neutron and gamma transport analyses were performed to design shielding around the VISION beam line, instrument shielding enclosure, beam stop, secondary shutter including a temporary beam stop for the still closed neighboring beam line to meet requirement is to achieve dose rates below 0.25 mrem/h at 30 cm from the shielding surface. The beam stop and the temporary beam stop analyses were performed with the discrete ordinate code DORT additionally to Monte Carlo analyses with the MCNPX code. Comparison of the results is presented.

  11. A vector matching method for analysing logic Petri nets

    NASA Astrophysics Data System (ADS)

    Du, YuYue; Qi, Liang; Zhou, MengChu

    2011-11-01

    Batch processing function and passing value indeterminacy in cooperative systems can be described and analysed by logic Petri nets (LPNs). To directly analyse the properties of LPNs, the concept of transition enabling vector sets is presented and a vector matching method used to judge the enabling transitions is proposed in this article. The incidence matrix of LPNs is defined; an equation about marking change due to a transition's firing is given; and a reachable tree is constructed. The state space explosion is mitigated to a certain extent from directly analysing LPNs. Finally, the validity and reliability of the proposed method are illustrated by an example in electronic commerce.

  12. Contamination analyses of technology mirror assembly optical surfaces

    NASA Technical Reports Server (NTRS)

    Germani, Mark S.

    1991-01-01

    Automated electron microprobe analyses were performed on tape lift samples from the Technology Mirror Assembly (TMA) optical surfaces. Details of the analyses are given, and the contamination of the mirror surfaces is discussed. Based on the automated analyses of the tape lifts from the TMA surfaces and the control blank, we can conclude that the particles identified on the actual samples were not a result of contamination due to the handling or sampling process itself and that the particles reflect the actual contamination on the surface of the mirror.

  13. NMC stratospheric analyses during the 1987 Antarctic expedition

    NASA Technical Reports Server (NTRS)

    Gelman, Melvyn E.; Newman, Paul A.

    1988-01-01

    Stratospheric constant pressure analyses of geopotential height and temperature, produced as part of regular operations at the National Meteorological Center (NMC), were used by several participants of the Antarctic Ozone Expedition. A brief decription is given of the NMC stratospheric analyses and the data that are used to derive them. In addition, comparisons of the analysis values at the locations of radiosonde and aircraft data are presented to provide indications for assessing the representativeness of the NMC stratospheric analyses during the 1987 Antarctic winter-spring period.

  14. Nonlinear structural and life analyses of a combustor liner

    NASA Technical Reports Server (NTRS)

    Moreno, V.; Meyers, G. J.; Kaufman, A.; Halford, G. R.

    1982-01-01

    Three dimensional, nonlinear finite element structural analyses were performed for a simulated combustor liner specimen to assess the capability of nonlinear analyses using classical inelastic material models to represent the thermoplastic creep response of the one half scale component. Results indicate continued cyclic hardening and ratcheting while experimental data suggested a stable stress strain response after only a few loading cycles. The computed stress strain history at the critical location was put into two life prediction methods, strainrange partitioning and a Pratt and Whitney combustor life prediction method to evaluate their ability to predict cyclic crack initiation. It is found that the life prediction analyses over predicted the observed cyclic crack initiation life.

  15. Incorporating cost-benefit analyses into software assurance planning

    NASA Technical Reports Server (NTRS)

    Feather, M. S.; Sigal, B.; Cornford, S. L.; Hutchinson, P.

    2001-01-01

    The objective is to use cost-benefit analyses to identify, for a given project, optimal sets of software assurance activities. Towards this end we have incorporated cost-benefit calculations into a risk management framework.

  16. Nonlinear shell analyses of the space shuttle solid rocket boosters

    NASA Technical Reports Server (NTRS)

    Knight, Norman F., Jr.; Gillian, Ronnie E.; Nemeth, Michael P.

    1989-01-01

    A variety of structural analyses have been performed on the Solid Rocket Boosters (SRB's) to provide information that would contribute to the understanding of the failure which destroyed the Space Shuttle Challenger. This paper describes nonlinear shell analyses that were performed to characterize the behavior of an overall SRB structure and a segment of the SRB in the vicinity of the External Tank Attachment (ETA) ring. Shell finite element models were used that would accurately reflect the global load transfer in an SRB in a manner such that nonlinear shell collapse and ovalization could be assessed. The purpose of these analyses was to calculate the overall deflection and stress distributions for these SRB models when subjected to mechanical loads corresponding to critical times during the launch sequence. Static analyses of these SRB models were performed using a snapshot picture of the loads. Analytical results obtained using these models show no evidence of nonlinear shell collapse for the pre-liftoff loading cases considered.

  17. An early "Atkins' Diet": RA Fisher analyses a medical "experiment".

    PubMed

    Senn, Stephen

    2006-04-01

    A study on vitamin absorption which RA Fisher analysed for WRG Atkins and co-authored with him is critically examined. The historical background as well as correspondence between Atkins and Fisher is presented.

  18. Using Inequality Measures to Incorporate Environmental Justice into Regulatory Analyses

    EPA Science Inventory

    Abstract: Formally evaluating how specific policy measures influence environmental justice is challenging, especially in the context of regulatory analyses in which quantitative comparisons are the norm. However, there is a large literature on developing and applying quantitative...

  19. Flood frequency analyses with annual and partial flood series

    NASA Astrophysics Data System (ADS)

    Bezak, N.; Brilly, M.; Sraj, M.

    2012-04-01

    The objective of the study was (1) to analyse the influence of time scale of the data on the results, (2) to analyse the relations between discharge, volume and time of flood waves of the Sava river at Litija (Slovenia), (3) to perform flood frequency analyses of peak discharges with annual and partial data series and compare the results and (4) to explore the influence of threshold value by POT method. Calculations and analyses were made for the period 1953-2010. Daily scale data sets (considering also local maximum) were used. The flood frequency analyses were based on anual and partial data series. The differences between daily and hourly time scale data sets were explored. Daily and hourly time scale hydrographs were compared and differences were analysed. Differences were adequately small. Daily time series with included maximums were logical choice because of the length of the daily time series and because hourly time series were not continuous due to gauging equipment failures. Important objective of the study was to analyse the relationship between discharge, volume and duration of flood waves. Baseflow was separated from continuous daily discharge measurements on simple and complex hydrographs. Simple graphical method with three points was used. Many different coefficients like base flow index were calculated and different combinations of correlation coefficient of wave components were examined. Annual maximum series were used to study the relationship between wave components. Flood frequency analyses were made with annual maximum series and partial duration series. Log-normal distribution, Pearson distribution type 3, log-Pearson distribution type 3, Gumbel distribution, exponential distribution, GEV distribution and GL distribution were used for annual maximum series. Simple equation of linear transformation was used to determine the design discharge and procedure which is proposed in Flood Estimation Handbook was used with GEV and GL distribution

  20. Room response analyses to investigate waste disposal issues

    SciTech Connect

    Arguello, J.G.; Weatherby, J.R.; Stone, C.M.; Morgan, H.S.; Wawersik, W.R.

    1991-01-01

    The long-term structural behavior of WIPP disposal rooms under various hypothetical repository conditions has been studied at Sandia National Laboratories for the past few years. This paper presents an overview of structural analyses that address issues dealing with the condition of the room and its contents. The analyses represent a progression in the development of a model for disposal room response that has encountered and overcome many computational challenges along the way. 13 refs., 8 figs.

  1. Doubly Latent Multilevel Analyses of Classroom Climate: An Illustration

    ERIC Educational Resources Information Center

    Morin, Alexandre J. S.; Marsh, Herbert W.; Nagengast, Benjamin; Scalas, L. Francesca

    2014-01-01

    Many classroom climate studies suffer from 2 critical problems: They (a) treat climate as a student-level (L1) variable in single-level analyses instead of a classroom-level (L2) construct in multilevel analyses; and (b) rely on manifest-variable models rather than on latent-variable models that control measurement error at L1 and L2, and sampling…

  2. A comparison of subgroup analyses in grant applications and publications.

    PubMed

    Boonacker, Chantal W B; Hoes, Arno W; van Liere-Visser, Karen; Schilder, Anne G M; Rovers, Maroeska M

    2011-07-15

    In this paper, the authors compare subgroup analyses as outlined in grant applications and their related publications. Grants awarded by the Netherlands Organization for Health Research and Development (ZonMw) from 2001 onward that were finalized before March 1, 2010, were studied. Of the 79 grant proposals, 50 (63%) were intervention studies, 18 (23%) were diagnostic studies, and 6 (8%) were prognostic studies. Subgroups were mentioned in 49 (62%) grant applications and in 53 (67%) publications. In 20 of the 79 projects (25%), the publications were completely in agreement with the grant proposal; that is, subgroups that were prespecified in the grant proposal were reported and no new subgroup analyses were introduced in the publications. Of the 149 prespecified subgroups, 46 (31%) were reported in the final report or scientific publications, and 143 of the 189 (76%) reported subgroups were based on post-hoc findings. For 77% of the subgroup analyses in the publications, there was no mention of whether these were prespecified or post hoc. Justification for subgroup analysis and methods to study subgroups were rarely reported. The authors conclude that there is a large discrepancy between grant applications and final publications regarding subgroup analyses. Both nonreporting prespecified subgroup analyses and reporting post-hoc subgroup analyses are common. More guidance is clearly needed.

  3. Economic analyses of rubella and rubella vaccines: a global review.

    PubMed Central

    Hinman, Alan R.; Irons, Beryl; Lewis, Merle; Kandola, Kami

    2002-01-01

    OBJECTIVE: To investigate whether the incorporation of rubella vaccine into immunization programmes in developing countries is economically justified. METHODS: A MEDLINE search was conducted for articles published between 1970 and 2000 that dealt with economic analyses of rubella and rubella-containing vaccines. The Eastern Mediterranean, South-East Asia, and Africa regional Index Medicus databases and the LILACS database for Latin America and the Caribbean were also searched. FINDINGS: For developed countries, five cost- benefit analyses of rubella vaccine and five of measles-mumps-rubella vaccine as well as two cost-effectiveness analyses were found. For developing countries, five cost analyses and five cost-benefit analyses were found. All the cost-benefit analyses had a benefit:cost ratio greater than 1 and the cost-effectiveness studies indicated that rubella immunization was a cost-effective means of reducing the impact of congenital rubella syndrome. However, the methodologies were not standardized. CONCLUSION: The data support the inclusion of rubella vaccine in the immunization programmes of both developing and developed countries and indicate economic benefits comparable to those associated with hepatitis B vaccine and Haemophilus influenzae type b vaccine. More studies should be carried out on costs for care and immunization using standardized methodologies and locally obtained information. PMID:12075361

  4. Comparison of retrospective analyses of the global ocean heat content

    NASA Astrophysics Data System (ADS)

    Chepurin, Gennady A.; Carton, James A.

    1999-07-01

    In this study, we compare seven retrospective analyses of basin- to global-scale upper ocean temperature. The analyses span a minimum of 10 years during the 50-year period since World War II. Three of the analyses (WOA-94, WHITE, BMRC) are based on objective analysis and thus, do not rely on a numerical forecast model. The remaining four (NCEP, WAJSOWICZ, ROSATI, SODA) are based on data assimilation in which the numerical forecast is provided by some form of the Geophysical Fluid Dynamics Laboratory Modular Ocean Model driven by historical winds. The comparison presented here is limited to heat content in the upper 250 m, information that is available for all analyses. The results are presented in three frequency bands: seasonal, interannual (periods of 1-5 years), and decadal (periods of 5-25 years). At seasonal frequencies, all of the analyses are quite similar. Otherwise, the differences among analyses are limited to the regions of the western boundary currents, and some regions in the Southern Hemisphere. At interannual frequencies, significant differences appear between the objective analyses and the data assimilation analyses. Along the equator in the Pacific, where variability is dominated by El Niño, the objective analyses have somewhat noisier fields, as well as reduced variance prior to 1980 due to lack of observations. Still, the correlation among analyses generally exceeds 80% in this region. Along the equator in the Atlantic, the correlation is lower (30-60%) although inspection of the time series shows that the same biennial progression of warm and cool events appears in all analyses since 1980. In the midlatitude Pacific agreement among objective analyses and data assimilation analyses is good. The analysis of Rosati et al. [Rosati, A., Gudgel, R., Miyakoda, K., 1995. Decadal analysis produced from an ocean assimilation system. Mon. Weather Rev., 123, 2, 206.] differs somewhat from the others apparently because in this analysis, the forecast model

  5. Accelerated safety analyses - structural analyses Phase I - structural sensitivity evaluation of single- and double-shell waste storage tanks

    SciTech Connect

    Becker, D.L.

    1994-11-01

    Accelerated Safety Analyses - Phase I (ASA-Phase I) have been conducted to assess the appropriateness of existing tank farm operational controls and/or limits as now stipulated in the Operational Safety Requirements (OSRs) and Operating Specification Documents, and to establish a technical basis for the waste tank operating safety envelope. Structural sensitivity analyses were performed to assess the response of the different waste tank configurations to variations in loading conditions, uncertainties in loading parameters, and uncertainties in material characteristics. Extensive documentation of the sensitivity analyses conducted and results obtained are provided in the detailed ASA-Phase I report, Structural Sensitivity Evaluation of Single- and Double-Shell Waste Tanks for Accelerated Safety Analysis - Phase I. This document provides a summary of the accelerated safety analyses sensitivity evaluations and the resulting findings.

  6. ChemCam analyses of the Pahrump Hills sediments in the context of other sediments analysed by the Curiosity rover

    NASA Astrophysics Data System (ADS)

    Mangold, N.; Forni, O.; Blaney, D. L.; Milliken, R.; Nachon, M.; Le Deit, L.; Gasnault, O.; Clegg, S.; Fisk, M.; Grotzinger, J.; Hurowitz, J.; Kah, L. C.; Le Mouélic, S.; McLennan, S.; Maurice, S.; Stack, K.; Sumner, D. Y.; Wiens, R. C.; MSL Team

    2015-10-01

    We report the results of ChemCam observations at the location of Pahrump Hills, analysed by the rover during the end of 2014 and beginning of 2015. Although Pahrump Hills sediment compositions are overall close to that of the coarser conglomerates analysed earlier by the rover, these observations show a strong variability in texture and composition, suggesting variations in source material and a complex aqueous history.

  7. [Methods, challenges and opportunities for big data analyses of microbiome].

    PubMed

    Sheng, Hua-Fang; Zhou, Hong-Wei

    2015-07-01

    Microbiome is a novel research field related with a variety of chronic inflamatory diseases. Technically, there are two major approaches to analysis of microbiome: metataxonome by sequencing the 16S rRNA variable tags, and metagenome by shot-gun sequencing of the total microbial (mainly bacterial) genome mixture. The 16S rRNA sequencing analyses pipeline includes sequence quality control, diversity analyses, taxonomy and statistics; metagenome analyses further includes gene annotation and functional analyses. With the development of the sequencing techniques, the cost of sequencing will decrease, and big data analyses will become the central task. Data standardization, accumulation, modeling and disease prediction are crucial for future exploit of these data. Meanwhile, the information property in these data, and the functional verification with culture-dependent and culture-independent experiments remain the focus in future research. Studies of human microbiome will bring a better understanding of the relations between the human body and the microbiome, especially in the context of disease diagnosis and therapy, which promise rich research opportunities. PMID:26198938

  8. Using inequality measures to incorporate environmental justice into regulatory analyses.

    PubMed

    Harper, Sam; Ruder, Eric; Roman, Henry A; Geggel, Amelia; Nweke, Onyemaechi; Payne-Sturges, Devon; Levy, Jonathan I

    2013-08-30

    Formally evaluating how specific policy measures influence environmental justice is challenging, especially in the context of regulatory analyses in which quantitative comparisons are the norm. However, there is a large literature on developing and applying quantitative measures of health inequality in other settings, and these measures may be applicable to environmental regulatory analyses. In this paper, we provide information to assist policy decision makers in determining the viability of using measures of health inequality in the context of environmental regulatory analyses. We conclude that quantification of the distribution of inequalities in health outcomes across social groups of concern, considering both within-group and between-group comparisons, would be consistent with both the structure of regulatory analysis and the core definition of environmental justice. Appropriate application of inequality indicators requires thorough characterization of the baseline distribution of exposures and risks, leveraging data generally available within regulatory analyses. Multiple inequality indicators may be applicable to regulatory analyses, and the choice among indicators should be based on explicit value judgments regarding the dimensions of environmental justice of greatest interest.

  9. Residual Strength Analyses of Riveted Lap-Splice Joints

    NASA Technical Reports Server (NTRS)

    Seshadri, B. R.; Newman, J. C., Jr.

    2000-01-01

    The objective of this paper was to analyze the crack-linkup behavior in riveted-stiffened lap-splice joint panels with small multiple-site damage (MSD) cracks at several adjacent rivet holes. Analyses are based on the STAGS (STructural Analysis of General Shells) code with the critical crack-tip-opening angle (CTOA) fracture criterion. To account for high constraint around a crack front, the "plane strain core" option in STAGS was used. The importance of modeling rivet flexibility with fastener elements that accurately model load transfer across the joint is discussed. Fastener holes are not modeled but rivet connectivity is accounted for by attaching rivets to the sheet on one side of the cracks that simulated both the rivet diameter and MSD cracks. Residual strength analyses made on 2024-T3 alloy (1.6-mm thick) riveted-lap-splice joints with a lead crack and various size MSD cracks were compared with test data from Boeing Airplane Company. Analyses were conducted for both restrained and unrestrained buckling conditions. Comparison of results from these analyses and results from lap-splice-joint test panels, which were partially restrained against buckling indicate that the test results were bounded by the failure loads predicted by the analyses with restrained and unrestrained conditions.

  10. Designing forgiveness interventions: guidance from five meta-analyses.

    PubMed

    Recine, Ann C

    2015-06-01

    The Nursing Interventions Classification system includes forgiveness facilitation as part of the research-based taxonomy of nursing interventions. Nurses need practical guidance in finding the type of intervention that works best in the nursing realm. Five meta-analyses of forgiveness interventions were reviewed to illuminate best practice. The only studies included were meta-analyses of forgiveness interventions in which the authors calculated effect size. Forgiveness interventions were shown to be helpful in addressing mental/emotional health. Components of effective interventions include recalling the offense, empathizing with the offender, committing to forgive, and overcoming feelings of unforgiveness. The meta-analyses showed that people receiving forgiveness interventions reported more forgiveness than those who had no intervention. Forgiveness interventions resulted in more hope and less depression and anxiety than no treatment. A process-based intervention is more effective than a shorter cognitive decision-based model. Limitations of the meta-analyses included inconsistency of measures and a lack of consensus on a definition of forgiveness. Notwithstanding these limitations, the meta-analyses offer strong evidence of what contributes to the effectiveness of forgiveness interventions. The implications of the studies are useful for designing evidence-based clinical forgiveness interventions to enhance nursing practice. PMID:25487180

  11. Traditional difference-score analyses of reasoning are flawed.

    PubMed

    Heit, Evan; Rotello, Caren M

    2014-04-01

    Studies of the belief bias effect in syllogistic reasoning have relied on three traditional difference score measures: the logic index, belief index, and interaction index. Dube, Rotello, and Heit (2010, 2011) argued that the interaction index incorrectly assumes a linear receiver operating characteristic (ROC). Here, all three measures are addressed. Simulations indicated that traditional analyses of reasoning experiments are likely to lead to incorrect conclusions. Two new experiments examined the role of instructional manipulations on the belief bias effect. The form of the ROCs violated assumptions of traditional measures. In comparison, signal detection theory (SDT) model-based analyses were a better match for the form of the ROCs, and implied that belief bias and instructional manipulations are predominantly response bias effects. Finally, reanalyses of previous studies of conditional reasoning also showed non-linear ROCs, violating assumptions of traditional analyses. Overall, reasoning research using traditional measures is at risk of drawing incorrect conclusions.

  12. Role of optimization in interdisciplinary analyses of naval structures

    NASA Technical Reports Server (NTRS)

    Dhir, S. K.; Hurwitz, M. M.

    1984-01-01

    The need for numerical design optimization of naval structures is discussed. The complexity of problems that arise due to the significant roles played by three major disciplines, i.e., structural mechanics, acoustics, and hydrodynamics are discussed. A major computer software effort that has recently begun at the David W. Taylor Naval Ship R&D Center to accommodate large multidisciplinary analyses is also described. In addition to primarily facilitating, via the use of data bases, interdisciplinary analyses for predicting the response of the Navy's ships and related structures, this software effort is expected to provide the analyst with a convenient numerical workbench for performing large numbers of analyses that may be necessary for optimizing the design performance. Finally, an example is included that investigates several aspects of optimizing a typical naval structure from the viewpoints of strength, hydrodynamic form, and acoustic characteristics.

  13. Genetic Analyses in Health Laboratories: Current Status and Expectations

    NASA Astrophysics Data System (ADS)

    Finotti, Alessia; Breveglieri, Giulia; Borgatti, Monica; Gambari, Roberto

    Genetic analyses performed in health laboratories involve adult patients, newborns, embryos/fetuses, pre-implanted pre-embryos, pre-fertilized oocytes and should meet the major medical needs of hospitals and pharmaceutical companies. Recent data support the concept that, in addition to diagnosis and prognosis, genetic analyses might lead to development of personalized therapy. Novel frontiers in genetic testing involve the development of single cell analyses and non-invasive assays, including those able to predict outcome of cancer pathologies by looking at circulating tumor cells, DNA, mRNA and microRNAs. In this respect, PCR-free diagnostics appears to be one of the most interesting and appealing approaches.

  14. Fourier Transform Mass Spectrometry: The Transformation of Modern Environmental Analyses

    PubMed Central

    Lim, Lucy; Yan, Fangzhi; Bach, Stephen; Pihakari, Katianna; Klein, David

    2016-01-01

    Unknown compounds in environmental samples are difficult to identify using standard mass spectrometric methods. Fourier transform mass spectrometry (FTMS) has revolutionized how environmental analyses are performed. With its unsurpassed mass accuracy, high resolution and sensitivity, researchers now have a tool for difficult and complex environmental analyses. Two features of FTMS are responsible for changing the face of how complex analyses are accomplished. First is the ability to quickly and with high mass accuracy determine the presence of unknown chemical residues in samples. For years, the field has been limited by mass spectrometric methods that were based on knowing what compounds of interest were. Secondly, by utilizing the high resolution capabilities coupled with the low detection limits of FTMS, analysts also could dilute the sample sufficiently to minimize the ionization changes from varied matrices. PMID:26784175

  15. Department of Energy's team's analyses of Soviet designed VVERs

    SciTech Connect

    Not Available

    1989-09-01

    The purpose of this report is to summarize the results of the US Department of Energy (DOE) Analysis Team's analyses of Soviet designed VVERs (Water-cooled, Water-moderated Energy Reactor). The principle objective of this undertaking is to provide a basis to better understand the safety related features of the Soviet designed VVERs to be better prepared to respond domestically in the event of an accident at such a unit. The USDOE Team's analyses are presented together with supporting and background information. The report is structured to allow the reader to develop an understanding of safety related features of Soviet designed VVERs (as well as the probable behavior of these units under a variety of off normal conditions), to understand the USDOE Team's analyses of Soviet designed VVERs, and to formulate informed opinions.

  16. Affymetrix GeneChip microarray preprocessing for multivariate analyses.

    PubMed

    McCall, Matthew N; Almudevar, Anthony

    2012-09-01

    Affymetrix GeneChip microarrays are the most widely used high-throughput technology to measure gene expression, and a wide variety of preprocessing methods have been developed to transform probe intensities reported by a microarray scanner into gene expression estimates. There have been numerous comparisons of these preprocessing methods, focusing on the most common analyses-detection of differential expression and gene or sample clustering. Recently, more complex multivariate analyses, such as gene co-expression, differential co-expression, gene set analysis and network modeling, are becoming more common; however, the same preprocessing methods are typically applied. In this article, we examine the effect of preprocessing methods on some of these multivariate analyses and provide guidance to the user as to which methods are most appropriate.

  17. Finite element analyses of a linear-accelerator electron gun

    SciTech Connect

    Iqbal, M. E-mail: muniqbal@ihep.ac.cn; Wasy, A.; Islam, G. U.; Zhou, Z.

    2014-02-15

    Thermo-structural analyses of the Beijing Electron-Positron Collider (BEPCII) linear-accelerator, electron gun, were performed for the gun operating with the cathode at 1000 °C. The gun was modeled in computer aided three-dimensional interactive application for finite element analyses through ANSYS workbench. This was followed by simulations using the SLAC electron beam trajectory program EGUN for beam optics analyses. The simulations were compared with experimental results of the assembly to verify its beam parameters under the same boundary conditions. Simulation and test results were found to be in good agreement and hence confirmed the design parameters under the defined operating temperature. The gun is operating continuously since commissioning without any thermal induced failures for the BEPCII linear accelerator.

  18. A study on quantitative analyses before and after injection of contrast medium in spine examinations performed by using diffusion weighted image

    NASA Astrophysics Data System (ADS)

    Cho, Jae-Hwan; Lee, Hae-Kag; Kim, Yong-Kyun; Dong, Kyung-Rae; Chung, Woon-Kwan; Joo, Kyu-Ji

    2013-02-01

    This study examined the changes in the signal-to-noise ratio (SNR), the contrast-to-noise ratio (CNR) and the apparent diffusion coefficient (ADC) of metastatic cancer in the lumbar region by using diffusion weighted image taken with a 1.5 T (Tesla) magnetic resonance (MR) scanner before and after injecting a contrast medium. The study enrolled 30 healthy people and 30 patients with metastatic spine cancer from patients who underwent a lumbar MRI scan from January 2011 to October 2012. A 1.5 T MR scanner was used to obtain the diffusion weighted images (DWIs) before and after injecting the contrast medium. In the group with metastatic spine cancer, the SNR and the CNR were measured in three parts among the L1-L5 lumbar vertebrae, which included the part with metastatic spine cancer, the area of the spine with spine cancer, and the area of spine under the region with cancer. In the acquired ADC map image, the SNRs and the ADCs of the three parts were measured in ADC map images. Among the healthy subjects, the measurements were conducted for the lumbar regions of L3-L5. According to the results, in the group with metastatic spine cancer, the SNR in the DWI before the contrast medium had been injected was lowest in the part with spine cancer. In the DWI after the contrast medium had been injected, the SNR and the CNR were increased in all three parts. In the ADC map image after the contrast medium had been injected, the SNR decreased in all three parts compared to the SNR before the contrast had been injected. The ADC after had been injected the contrast medium was decreased in all three parts compared to that before the contrast medium had been injected. In the healthy group, the SNR was increased in the L3-L5 lumbar regions in the DWI. In the ADC map image, the SNR in all the three parts was decreased in the DWI after injecting the contrast medium had been injected. The ADC in the ADC map image was also decreased in all three parts.

  19. Models Extracted from Text for System-Software Safety Analyses

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.

    2010-01-01

    This presentation describes extraction and integration of requirements information and safety information in visualizations to support early review of completeness, correctness, and consistency of lengthy and diverse system safety analyses. Software tools have been developed and extended to perform the following tasks: 1) extract model parts and safety information from text in interface requirements documents, failure modes and effects analyses and hazard reports; 2) map and integrate the information to develop system architecture models and visualizations for safety analysts; and 3) provide model output to support virtual system integration testing. This presentation illustrates the methods and products with a rocket motor initiation case.

  20. Seismic hazard and site response analyses for Rio Caribe

    SciTech Connect

    Sully, J.P.; Gajardo, E.; Paga, M.; Fernandez, A.; Cascante, G.

    1995-12-01

    An evaluation of seismic hazard was performed for the proposed Rio Caribe offshore development in order to verify the seismic parameters for the engineering design. A compilation of the historical and instrumental data suggested that the seismic environment is different from that assumed in the API RP2A code. A series of sensitivity analyses for the seismic response were performed to evaluate uncertainties in the response taking into account both seismic and geotechnical variations. The results of these analyses are presented in this paper and applied to provide a more realistic design acceleration for the offshore platform.

  1. Iterative categorization (IC): a systematic technique for analysing qualitative data.

    PubMed

    Neale, Joanne

    2016-06-01

    The processes of analysing qualitative data, particularly the stage between coding and publication, are often vague and/or poorly explained within addiction science and research more broadly. A simple but rigorous and transparent technique for analysing qualitative textual data, developed within the field of addiction, is described. The technique, iterative categorization (IC), is suitable for use with inductive and deductive codes and can support a range of common analytical approaches, e.g. thematic analysis, Framework, constant comparison, analytical induction, content analysis, conversational analysis, discourse analysis, interpretative phenomenological analysis and narrative analysis. Once the data have been coded, the only software required is a standard word processing package. Worked examples are provided.

  2. Computational Aeroelastic Analyses of a Low-Boom Supersonic Configuration

    NASA Technical Reports Server (NTRS)

    Silva, Walter A.; Sanetrik, Mark D.; Chwalowski, Pawel; Connolly, Joseph

    2015-01-01

    An overview of NASA's Commercial Supersonic Technology (CST) Aeroservoelasticity (ASE) element is provided with a focus on recent computational aeroelastic analyses of a low-boom supersonic configuration developed by Lockheed-Martin and referred to as the N+2 configuration. The overview includes details of the computational models developed to date including a linear finite element model (FEM), linear unsteady aerodynamic models, unstructured CFD grids, and CFD-based aeroelastic analyses. In addition, a summary of the work involving the development of aeroelastic reduced-order models (ROMs) and the development of an aero-propulso-servo-elastic (APSE) model is provided.

  3. Publication bias in dermatology systematic reviews and meta-analyses.

    PubMed

    Atakpo, Paul; Vassar, Matt

    2016-05-01

    Systematic reviews and meta-analyses in dermatology provide high-level evidence for clinicians and policy makers that influence clinical decision making and treatment guidelines. One methodological problem with systematic reviews is the under representation of unpublished studies. This problem is due in part to publication bias. Omission of statistically non-significant data from meta-analyses may result in overestimation of treatment effect sizes which may lead to clinical consequences. Our goal was to assess whether systematic reviewers in dermatology evaluate and report publication bias. Further, we wanted to conduct our own evaluation of publication bias on meta-analyses that failed to do so. Our study considered systematic reviews and meta-analyses from ten dermatology journals from 2006 to 2016. A PubMed search was conducted, and all full-text articles that met our inclusion criteria were retrieved and coded by the primary author. 293 articles were included in our analysis. Additionally, we formally evaluated publication bias in meta-analyses that failed to do so using trim and fill and cumulative meta-analysis by precision methods. Publication bias was mentioned in 107 articles (36.5%) and was formally evaluated in 64 articles (21.8%). Visual inspection of a funnel plot was the most common method of evaluating publication bias. Publication bias was present in 45 articles (15.3%), not present in 57 articles (19.5%) and not determined in 191 articles (65.2%). Using the trim and fill method, 7 meta-analyses (33.33%) showed evidence of publication bias. Although the trim and fill method only found evidence of publication bias in 7 meta-analyses, the cumulative meta-analysis by precision method found evidence of publication bias in 15 meta-analyses (71.4%). Many of the reviews in our study did not mention or evaluate publication bias. Further, of the 42 articles that stated following PRISMA reporting guidelines, 19 (45.2%) evaluated for publication bias. In

  4. Design basis event consequence analyses for the Yucca Mountain project

    SciTech Connect

    Orvis, D.D.; Haas, M.N.; Martin, J.H.

    1997-02-01

    Design basis event (DBE) definition and analysis is an ongoing and integrated activity among the design and analysis groups of the Yucca Mountain Project (YMP). DBE`s are those that potentially lead to breach of the waste package and waste form (e.g., spent fuel rods) with consequent release of radionuclides to the environment. A Preliminary Hazards Analysis (PHA) provided a systematic screening of external and internal events that were candidate DBE`s that will be subjected to analyses for radiological consequences. As preparation, pilot consequence analyses for the repository subsurface and surface facilities have been performed to define the methodology, data requirements, and applicable regulatory limits.

  5. VIPRE modeling of VVER-1000 reactor core for DNB analyses

    SciTech Connect

    Sung, Y.; Nguyen, Q.; Cizek, J.

    1995-09-01

    Based on the one-pass modeling approach, the hot channels and the VVER-1000 reactor core can be modeled in 30 channels for DNB analyses using the VIPRE-01/MOD02 (VIPRE) code (VIPRE is owned by Electric Power Research Institute, Palo Alto, California). The VIPRE one-pass model does not compromise any accuracy in the hot channel local fluid conditions. Extensive qualifications include sensitivity studies of radial noding and crossflow parameters and comparisons with the results from THINC and CALOPEA subchannel codes. The qualifications confirm that the VIPRE code with the Westinghouse modeling method provides good computational performance and accuracy for VVER-1000 DNB analyses.

  6. Using Microsoft Office Excel 2007 to conduct generalized matching analyses.

    PubMed

    Reed, Derek D

    2009-01-01

    The generalized matching equation is a robust and empirically supported means of analyzing relations between reinforcement and behavior. Unfortunately, no simple task analysis is available to behavior analysts interested in using the matching equation to evaluate data in clinical or applied settings. This technical article presents a task analysis for the use of Microsoft Excel to analyze and plot the generalized matching equation. Using a data-based case example and a step-by-step guide for completing the analysis, these instructions are intended to promote the use of quantitative analyses by researchers with little to no experience in quantitative analyses or the matching law.

  7. Fracture mechanics analyses for skin-stiffener debonding

    NASA Technical Reports Server (NTRS)

    Raju, I. S.; Sistla, R.; Krishnamurthy, T.; Lotts, C. G.

    1993-01-01

    The debond configurations presently subjected to 3D FEM fracture mechanics analyses are respectively of the flange-skin strip and skin-stiffener configuration type. Two methods employing the virtual crack closure technique were used to evaluate the strain energy release rate, or 'G-value' distributions across the debond front. Both methods yielded nearly identical G-value distributions for the debond configurations studied; they were compared with plane strain and shell analyses results from the literature for the flange skin strip configuration, and found to be in good agreement. Mode II is dominant for the skin-stiffener debond configuration.

  8. The Vienna Temperature Series: Strengths and weaknesses for the use in climate change analyses

    NASA Astrophysics Data System (ADS)

    Auer, I.; Böhm, R.; Gruber, C.; Jurković, A.

    2010-09-01

    Strakosch-Grassmann (1932*) reports about the first instrumental measurements in Vienna in 1697 for a span of eight months only. Later, continuous measurements have been carried out at the observatory of the Jesuit College since 1734, at the k.k. Universitätssternwarte (astronomical observatory of the University of Vienna) since 1762. Unfortunately, most of the data before 1775 have gone lost. The HISTALP (http://www.zamg.ac.at/histalp) temperature series of Vienna is a composite of Wien-Universitätssternwarte, Wien-Favoritenstraße und Wien-Hohe Warte. It allows studying climate variability for more than 235 years and it has been used very often in national and international studies. Although the Vienna series has been homogenized and quality checked with highest carefulness some remaining uncertainties are persisting. This especially concerns uncertainties of the very early measurements due to insufficient sheltering, and measurements of the last 60 years due to an increasing trend of the Viennese urban heat island. *Strakosch-Graßmann G, 1932. Neue Quellen zur Geschichte der Witterung in Europa vom 16. Bis zum 18. Jahrhundert. Met. Zeitschr. 1932, S 397.

  9. Analysing the Implemented Curriculum of Mathematics in Preschool Education

    ERIC Educational Resources Information Center

    Zacharos, Konstantinos; Koustourakis, Gerasimos; Papadimitriou, Konstantina

    2014-01-01

    The purpose of this paper is to contribute to development of research tools for observation and analysis of educational practices used by teachers in preschool classrooms. More specifically, we approached the implemented curriculum of mathematics in Greek preschool education. We analysed the recorded data from a week of teaching practices in eight…

  10. Astronomy sortie mission definition study. Addendum: Follow-on analyses

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Results of design analyses, trade studies, and planning data of the Astronomy Sortie Mission Definition Study are presented. An in-depth analysis of UV instruments, nondeployed solar payload, and on-orbit access is presented. Planning data are considered, including the cost and schedules associated with the astronomy instruments and/or support hardware. Costs are presented in a parametric fashion.

  11. Note on the chromatographic analyses of marine polyunsaturated fatty acids

    USGS Publications Warehouse

    Schultz, D.M.; Quinn, J.G.

    1977-01-01

    Gas-liquid chromatography was used to study the effects of saponification/methylation and thin-layer chromatographic isolation on the analyses of polyunsaturated fatty acids. Using selected procedures, the qualitative and quantitative distribution of these acids in marine organisms can be determined with a high degree of accuracy. ?? 1977 Springer-Verlag.

  12. Chemical analyses of surface waters in Oklahoma, September - December, 1944

    USGS Publications Warehouse

    U.S. Geological Survey

    1945-01-01

    Red River at Denison Dam, Texas Sport samples were collected at the remainder of the stations. The analyses of the spot samples were made largely in a laboratory provided by the Oklahoma A. & M. College, under the supervision of Dr. O.M. Smith, Head, Department of Chemistry; Dr. S.R. Wood, Associate Professor of Chemistry; and W.W. Hastings, U.S. Geological Survey. The daily samples were analyzed in the water resources laboratory of the Geological Survey at Austin, Texas. These data have been summarized in a report to the Oklahoma Planning and Resources Board prepared by the U.S. Geological Survey, March 1, 1945. The streams of Oklahoma are classified into two major drainage basins: the Arkansas River and the Red River and their tributaries. The attached analyses are arranged in geographical order for their respective drainage basins, with records listed in downstream order for stations on the main stem first, followed by the analyses for the tributaries. When available, the mean daily discharge is given for the analyses.

  13. DEMOGRAPHY AND VIABILITY ANALYSES OF A DIAMONDBACK TERRAPIN POPULATION

    EPA Science Inventory

    The diamondback terrapin Malaclemys terrapin is a long-lived species with special management requirements, but quantitative analyses to support management are lacking. I analyzed mark-recapture data and constructed an age-classified matrix population model to determine the status...

  14. Engineering analyses of large precision cathode strip chambers for GEM

    SciTech Connect

    Horvath, J.A.; Belser, F.C.; Pratuch, S.M.; Wuest, C.R.; Mitselmakher, G.; Gordeev, A.; Johnson, C.V. |; Polychronakos, V.A.; Golutvin, I.A.

    1993-10-21

    Structural analyses of large precision cathode strip chambers performed up to the date of this publication are documented. Mechanical property data for typical chamber materials are included. This information, originally intended to be an appendix to the {open_quotes}CSC Structural Design Bible,{close_quotes} is presented as a guide for future designers of large chambers.

  15. Analyses of Selected Provisions of Proposed Energy Legislation: 2003

    EIA Publications

    2003-01-01

    This study responds to a July 31, 2003 request from Senator Byron L. Dorgan. The study is based primarily on analyses the Energy Information Administration has previously done for studies requested by Congress. It includes analysis of the Renewable Portfolio Standard, Renewable Fuels Standard, production in the Alaskan National Wildlife Refuge, the construction of an Alaskan Natural Gas pipeline, and various tax provisions.

  16. A Method to Improve Learning Analysing Communication in Team Working

    ERIC Educational Resources Information Center

    Bermejo, Miren; Sanchez, Ana; Gutierrez, Julian; Perez, Tomas A.

    2011-01-01

    In recent years learning how to work in teams has become a common subject in higher education. Communication between student team members can be monitored using a bulletin board system, and hence, analyse individual and group role development. The composition and distribution of roles in a team are relevant characteristics that will considerably…

  17. Matrix Summaries Improve Research Reports: Secondary Analyses Using Published Literature

    ERIC Educational Resources Information Center

    Zientek, Linda Reichwein; Thompson, Bruce

    2009-01-01

    Correlation matrices and standard deviations are the building blocks of many of the commonly conducted analyses in published research, and AERA and APA reporting standards recommend their inclusion when reporting research results. The authors argue that the inclusion of correlation/covariance matrices, standard deviations, and means can enhance…

  18. Talking about Brine Shrimps: Three Ways of Analysing Pupil Conversations.

    ERIC Educational Resources Information Center

    Tunnicliffe, Sue Dale; Reiss, Michael J.

    1999-01-01

    Applies three distinct analyses to recorded and transcribed student conversations (n=240) about brine shrimps. The complementary analytic methods provide information on the content of pupils' conversations in terms of the observations made, the ways in which pupils make sense of their observations, and the ways in which students use conversation…

  19. miRNA Expression Analyses in Prostate Cancer Clinical Tissues

    PubMed Central

    Bucay, Nathan; Shahryari, Varahram; Majid, Shahana; Yamamura, Soichiro; Mitsui, Yozo; Tabatabai, Z. Laura; Greene, Kirsten; Deng, Guoren; Dahiya, Rajvir; Tanaka, Yuichiro; Saini, Sharanjot

    2015-01-01

    A critical challenge in prostate cancer (PCa) clinical management is posed by the inadequacy of currently used biomarkers for disease screening, diagnosis, prognosis and treatment. In recent years, microRNAs (miRNAs) have emerged as promising alternate biomarkers for prostate cancer diagnosis and prognosis. However, the development of miRNAs as effective biomarkers for prostate cancer heavily relies on their accurate detection in clinical tissues. miRNA analyses in prostate cancer clinical specimens is often challenging owing to tumor heterogeneity, sampling errors, stromal contamination etc. The goal of this article is to describe a simplified workflow for miRNA analyses in archived FFPE or fresh frozen prostate cancer clinical specimens using a combination of quantitative real-time PCR (RT-PCR) and in situ hybridization (ISH). Within this workflow, we optimize the existing methodologies for miRNA extraction from FFPE and frozen prostate tissues and expression analyses by Taqman-probe based miRNA RT-PCR. In addition, we describe an optimized method for ISH analyses formiRNA detection in prostate tissues using locked nucleic acid (LNA)- based probes. Our optimized miRNA ISH protocol can be applied to prostate cancer tissue slides or prostate cancer tissue microarrays (TMA). PMID:26382040

  20. Commercial Photography: Task Analyses. Competency-Based Education.

    ERIC Educational Resources Information Center

    Endo, Paula; Morrell, Linda

    These task analyses are designed to be used in combination with the "Trade and Industrial Education Service Area Resource" in order to implement competency-based education in the commercial photography program in Virginia. The task analysis document contains the task inventory, suggested task sequence lists, and content outlines for the courses in…

  1. Creation of a knowledge management system for QT analyses.

    PubMed

    Tornøe, Christoffer W; Garnett, Christine E; Wang, Yaning; Florian, Jeffry; Li, Michael; Gobburu, Jogarao V

    2011-07-01

    An increasing number of thorough QT (TQT) reports are being submitted to the US Food and Drug Administration's interdisciplinary review team for QT (IRT-QT), requiring time-intensive quantitative analyses by a multidisciplinary review team within 45 days. This calls for systematic learning to guide future trials and policies by standardizing and automating the QT analyses to improve review efficiency, provide consistent advice, and enable pooled data analyses to answer key regulatory questions. The QT interval represents the time from initiation of ventricular depolarization to completion of ventricular repolarization recorded by electrocardiograph (ECG) and is used in the proarrhythmic risk assessment. The developed QT knowledge management system is implemented in the R package "QT." Data from 11 crossover TQT studies including time-matched ECGs and pharmacokinetic measurements following single doses of 400 to 1200 mg moxifloxacin were used for the QT analysis example. The automated workflow was divided into 3 components (data management, analysis, and archival). The generated data sets, scripts, tables, and graphs are automatically stored in a queryable repository and summarized in an analysis report. More than 100 TQT studies have been analyzed using the system since 2007. This has dramatically reduced the time needed to review TQT studies and has made the IRT-QT reviews consistent across reviewers. Furthermore, the system enables leveraging prior knowledge through pooled data analyses to answer policy-related questions and to understand the various effects that influence study results. PMID:20978278

  2. Speech Analyses of Four Children with Repaired Cleft Palates.

    ERIC Educational Resources Information Center

    Powers, Gene R.; And Others

    1990-01-01

    Spontaneous speech samples were collected from four three-year olds with surgically repaired cleft palates. Analyses showed that subjects were similar to one another with respect to their phonetic inventories but differed considerably in the frequency and types of phonological processes used. (Author/JDD)

  3. 44 CFR 1.9 - Regulatory impact analyses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... HOMELAND SECURITY GENERAL RULEMAKING; POLICY AND PROCEDURES General § 1.9 Regulatory impact analyses. (a... monetary terms, and the identification of those likely to receive the benefits; (2) A description of the potential costs of the rule, including any adverse effects that cannot be quantified in monetary terms,...

  4. Principal Components Analyses of Predictor Variables in Dental Education.

    ERIC Educational Resources Information Center

    Zullo, Thomas G.

    This study was undertaken to determine the degree of factorial invariance that exists in a battery of predictor variables commonly used in the selection of applicants for dental school. The following variables were used in the analyses performed: 13 subscores from the Dental Aptitude Test Battery, Overall QPA, Required Courses QPA, years of…

  5. Analysing the Social Networks constituted by Open Source communities

    NASA Astrophysics Data System (ADS)

    Concas, Giulio; Lisci, Manuela; Pinna, Sandro; Porruvecchio, Guido; Uras, Selene

    2008-11-01

    In this study on Open Source communities, we examined some important aspects about communication among participants to developers mailing lists. We utilized Social Network Analysis approach to analyse this particular kind of communities, in order to better understand interaction among members, individuate communicational flows and discover whether there is a subsequential community coordination and control.

  6. Medical Isotope Production Analyses In KIPT Neutron Source Facility

    SciTech Connect

    Talamo, Alberto; Gohar, Yousry

    2016-01-01

    Medical isotope production analyses in Kharkov Institute of Physics and Technology (KIPT) neutron source facility were performed to include the details of the irradiation cassette and the self-shielding effect. An updated detailed model of the facility was used for the analyses. The facility consists of an accelerator-driven system (ADS), which has a subcritical assembly using low-enriched uranium fuel elements with a beryllium-graphite reflector. The beryllium assemblies of the reflector have the same outer geometry as the fuel elements, which permits loading the subcritical assembly with different number of fuel elements without impacting the reflector performance. The subcritical assembly is driven by an external neutron source generated from the interaction of 100-kW electron beam with a tungsten target. The facility construction was completed at the end of 2015, and it is planned to start the operation during the year of 2016. It is the first ADS in the world, which has a coolant system for removing the generated fission power. Argonne National Laboratory has developed the design concept and performed extensive design analyses for the facility including its utilization for the production of different radioactive medical isotopes. 99Mo is the parent isotope of 99mTc, which is the most commonly used medical radioactive isotope. Detailed analyses were performed to define the optimal sample irradiation location and the generated activity, for several radioactive medical isotopes, as a function of the irradiation time.

  7. Creation of a knowledge management system for QT analyses.

    PubMed

    Tornøe, Christoffer W; Garnett, Christine E; Wang, Yaning; Florian, Jeffry; Li, Michael; Gobburu, Jogarao V

    2011-07-01

    An increasing number of thorough QT (TQT) reports are being submitted to the US Food and Drug Administration's interdisciplinary review team for QT (IRT-QT), requiring time-intensive quantitative analyses by a multidisciplinary review team within 45 days. This calls for systematic learning to guide future trials and policies by standardizing and automating the QT analyses to improve review efficiency, provide consistent advice, and enable pooled data analyses to answer key regulatory questions. The QT interval represents the time from initiation of ventricular depolarization to completion of ventricular repolarization recorded by electrocardiograph (ECG) and is used in the proarrhythmic risk assessment. The developed QT knowledge management system is implemented in the R package "QT." Data from 11 crossover TQT studies including time-matched ECGs and pharmacokinetic measurements following single doses of 400 to 1200 mg moxifloxacin were used for the QT analysis example. The automated workflow was divided into 3 components (data management, analysis, and archival). The generated data sets, scripts, tables, and graphs are automatically stored in a queryable repository and summarized in an analysis report. More than 100 TQT studies have been analyzed using the system since 2007. This has dramatically reduced the time needed to review TQT studies and has made the IRT-QT reviews consistent across reviewers. Furthermore, the system enables leveraging prior knowledge through pooled data analyses to answer policy-related questions and to understand the various effects that influence study results.

  8. Developing Critical Thinking about Reporting of Bayesian Analyses

    ERIC Educational Resources Information Center

    Pullenayegum, Eleanor M.; Guo, Qing; Hopkins, Robert B.

    2012-01-01

    Graduate students in the health sciences who hope to become independent researchers must be able to write up their results at a standard suitable for submission to peer-reviewed journals. Bayesian analyses are still rare in the medical literature, and students are often unclear on what should be included in a manuscript. Whilst there are published…

  9. Rainbow: A Framework for Analysing Computer-Mediated Pedagogical Debates

    ERIC Educational Resources Information Center

    Baker, Michael; Andriessen, Jerry; Lund, Kristine; van Amelsvoort, Marie; Quignard, Matthieu

    2007-01-01

    In this paper we present a framework for analysing when and how students engage in a specific form of interactive knowledge elaboration in CSCL environments: broadening and deepening understanding of a space of debate. The framework is termed "Rainbow," as it comprises seven principal analytical categories, to each of which a colour is assigned,…

  10. How to Critically Read Ecological Meta-Analyses

    ERIC Educational Resources Information Center

    Lortie, Christopher J.; Stewart, Gavin; Rothstein, Hannah; Lau, Joseph

    2015-01-01

    Meta-analysis offers ecologists a powerful tool for knowledge synthesis. Albeit a form of review, it also shares many similarities with primary empirical research. Consequently, critical reading of meta-analyses incorporates criteria from both sets of approaches particularly because ecology is a discipline that embraces heterogeneity and broad…

  11. Component Analyses Using Single-Subject Experimental Designs: A Review

    ERIC Educational Resources Information Center

    Ward-Horner, John; Sturmey, Peter

    2010-01-01

    A component analysis is a systematic assessment of 2 or more independent variables or components that comprise a treatment package. Component analyses are important for the analysis of behavior; however, previous research provides only cursory descriptions of the topic. Therefore, in this review the definition of "component analysis" is discussed,…

  12. 76 FR 63913 - Commercial Building Workforce Job/Task Analyses

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-14

    ... of Energy Efficiency and Renewable Energy Commercial Building Workforce Job/Task Analyses AGENCY... and utility ratepayer-funded energy efficiency programs and private sector commercial building... INFORMATION CONTACT: Sonal Kemkar, Building Technologies Program, Mailstop EE-2J, Office of Energy...

  13. NAA For Human Serum Analysis: Comparison With Conventional Analyses

    SciTech Connect

    Oliveira, Laura C.; Zamboni, Cibele B.; Medeiros, Jose A. G.; Azevedo, Maria R.

    2010-08-04

    Instrumental and Comparator methods of Neutron Activation Analysis (NAA) were applied to determine elements of clinical relevancy in serum samples of adult population (Sao Paulo city, Brazil). A comparison with the conventional analyses, Colorimetric for calcium, Titrymetric for chlorine and Ion Specific Electrode for sodium and potassium determination were also performed permitting a discussion about the performance of NAA methods for clinical chemistry research.

  14. Vibro-Acoustic FE Analyses of the Saab 2000 Aircraft

    NASA Technical Reports Server (NTRS)

    Green, Inge S.

    1992-01-01

    A finite element model of the Saab 2000 fuselage structure and interior cavity has been created in order to compute the noise level in the passenger cabin due to propeller noise. Areas covered in viewgraph format include the following: coupled acoustic/structural noise; data base creation; frequency response analysis; model validation; and planned analyses.

  15. Development and Analyses of the Coping Stress Inventory

    ERIC Educational Resources Information Center

    Gadzella, Bernadette M.; Pierce, Devin; Young, Adena

    2008-01-01

    This is a report on the development of a coping stress inventory and the analyses of the data collected from 344 participants. The Coping Stress Inventory, CSI, with 16 items intercorrelated in the categories (Behavioral, Emotional, and Cognitive Appraisal). The internal consistency for the CSI was 0.77. Responses to the CSI were compared (a)…

  16. Systematic Processing of Clementine Data for Scientific Analyses

    NASA Technical Reports Server (NTRS)

    Mcewen, A. S.

    1993-01-01

    If fully successful, the Clementine mission will return about 3,000,000 lunar images and more than 5000 images of Geographos. Effective scientific analyses of such large datasets require systematic processing efforts. Concepts for two such efforts are described: glogal multispectral imaging of the moon; and videos of Geographos.

  17. Analysing Harmonic Motions with an iPhone's Magnetometer

    ERIC Educational Resources Information Center

    Yavuz, Ahmet; Temiz, Burak Kagan

    2016-01-01

    In this paper, we propose an experiment for analysing harmonic motion using an iPhone's (or iPad's) magnetometer. This experiment consists of the detection of magnetic field variations obtained from an iPhone's magnetometer sensor. A graph of harmonic motion is directly displayed on the iPhone's screen using the "Sensor Kinetics"…

  18. "Analysing Genre: Language Use in Professional Settings." A Review.

    ERIC Educational Resources Information Center

    Drury, Helen

    1995-01-01

    "Analysing Genre," by Vijay K. Bhatia, is a timely addition to the literature on genre analysis in English for specific purposes. It is divided into three parts: the first provides theoretical background; the second explains how genre analysis works in different academic and professional settings; and the third exemplifies the application of genre…

  19. How Can the Relationship between Argumentation and Proof Be Analysed?

    ERIC Educational Resources Information Center

    Pedemonte, Bettina

    2007-01-01

    The paper presents a characterisation about argumentation and proof in mathematics. On the basis of contemporary linguistic theories, the hypothesis that proof is a special case of argumentation is put forward and Toulmin's model is proposed as a methodological tool to compare them. This model can be used to detect and analyse the structure of an…

  20. Phospholipid and Respiratory Quinone Analyses From Extreme Environments

    NASA Astrophysics Data System (ADS)

    Pfiffner, S. M.

    2008-12-01

    Extreme environments on Earth have been chosen as surrogate sites to test methods and strategies for the deployment of space craft in the search for extraterrestrial life. Surrogate sites for many of the NASA astrobiology institutes include the South African gold mines, Canadian subpermafrost, Atacama Desert, and acid rock drainage. Soils, sediments, rock cores, fracture waters, biofilms, and service and drill waters represent the types of samples collected from these sites. These samples were analyzed by gas chromatography mass spectrometry for phospholipid fatty acid methyl esters and by high performance liquid chromatography atmospheric pressure chemical ionization tandem mass spectrometry for respiratory quinones. Phospholipid analyses provided estimates of biomass, community composition, and compositional changes related to nutritional limitations or exposure to toxic conditions. Similar to phospholipid analyses, respiratory quinone analyses afforded identification of certain types of microorganisms in the community based on respiration and offered clues to in situ redox conditions. Depending on the number of samples analyzed, selected multivariate statistical methods were applied to relate membrane lipid results with site biogeochemical parameters. Successful detection of life signatures and refinement of methodologies at surrogate sites on Earth will be critical for the recognition of extraterrestrial life. At this time, membrane lipid analyses provide useful information not easily obtained by other molecular techniques.

  1. 24 CFR 81.65 - Other information and analyses.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Other information and analyses. 81.65 Section 81.65 Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development THE SECRETARY OF HUD'S REGULATION OF THE FEDERAL NATIONAL MORTGAGE ASSOCIATION...

  2. 24 CFR 81.65 - Other information and analyses.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 1 2011-04-01 2011-04-01 false Other information and analyses. 81.65 Section 81.65 Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development THE SECRETARY OF HUD'S REGULATION OF THE FEDERAL NATIONAL MORTGAGE ASSOCIATION...

  3. miRNA Expression Analyses in Prostate Cancer Clinical Tissues.

    PubMed

    Bucay, Nathan; Shahryari, Varahram; Majid, Shahana; Yamamura, Soichiro; Mitsui, Yozo; Tabatabai, Z Laura; Greene, Kirsten; Deng, Guoren; Dahiya, Rajvir; Tanaka, Yuichiro; Saini, Sharanjot

    2015-01-01

    A critical challenge in prostate cancer (PCa) clinical management is posed by the inadequacy of currently used biomarkers for disease screening, diagnosis, prognosis and treatment. In recent years, microRNAs (miRNAs) have emerged as promising alternate biomarkers for prostate cancer diagnosis and prognosis. However, the development of miRNAs as effective biomarkers for prostate cancer heavily relies on their accurate detection in clinical tissues. miRNA analyses in prostate cancer clinical specimens is often challenging owing to tumor heterogeneity, sampling errors, stromal contamination etc. The goal of this article is to describe a simplified workflow for miRNA analyses in archived FFPE or fresh frozen prostate cancer clinical specimens using a combination of quantitative real-time PCR (RT-PCR) and in situ hybridization (ISH). Within this workflow, we optimize the existing methodologies for miRNA extraction from FFPE and frozen prostate tissues and expression analyses by Taqman-probe based miRNA RT-PCR. In addition, we describe an optimized method for ISH analyses formiRNA detection in prostate tissues using locked nucleic acid (LNA)- based probes. Our optimized miRNA ISH protocol can be applied to prostate cancer tissue slides or prostate cancer tissue microarrays (TMA). PMID:26382040

  4. Guidelines for Meta-Analyses of Counseling Psychology Research

    ERIC Educational Resources Information Center

    Quintana, Stephen M.; Minami, Takuya

    2006-01-01

    This article conceptually describes the steps in conducting quantitative meta-analyses of counseling psychology research with minimal reliance on statistical formulas. The authors identify sources that describe necessary statistical formula for various meta-analytic calculations and describe recent developments in meta-analytic techniques. The…

  5. Frequency analyses for recent regional floods in the United States

    USGS Publications Warehouse

    Melcher, Nick B.; Martinez, Patsy G.

    1996-01-01

    During 1993-95, significant floods that resulted in record-high river stages, loss of life, and significant property damage occurred in the United States. The floods were caused by unique global weather patterns that produced large amounts of rain over large areas. Standard methods for flood-frequency analyses may not adequately consider the probability of recurrence of these global weather patterns.

  6. miRNA Expression Analyses in Prostate Cancer Clinical Tissues.

    PubMed

    Bucay, Nathan; Shahryari, Varahram; Majid, Shahana; Yamamura, Soichiro; Mitsui, Yozo; Tabatabai, Z Laura; Greene, Kirsten; Deng, Guoren; Dahiya, Rajvir; Tanaka, Yuichiro; Saini, Sharanjot

    2015-09-08

    A critical challenge in prostate cancer (PCa) clinical management is posed by the inadequacy of currently used biomarkers for disease screening, diagnosis, prognosis and treatment. In recent years, microRNAs (miRNAs) have emerged as promising alternate biomarkers for prostate cancer diagnosis and prognosis. However, the development of miRNAs as effective biomarkers for prostate cancer heavily relies on their accurate detection in clinical tissues. miRNA analyses in prostate cancer clinical specimens is often challenging owing to tumor heterogeneity, sampling errors, stromal contamination etc. The goal of this article is to describe a simplified workflow for miRNA analyses in archived FFPE or fresh frozen prostate cancer clinical specimens using a combination of quantitative real-time PCR (RT-PCR) and in situ hybridization (ISH). Within this workflow, we optimize the existing methodologies for miRNA extraction from FFPE and frozen prostate tissues and expression analyses by Taqman-probe based miRNA RT-PCR. In addition, we describe an optimized method for ISH analyses formiRNA detection in prostate tissues using locked nucleic acid (LNA)- based probes. Our optimized miRNA ISH protocol can be applied to prostate cancer tissue slides or prostate cancer tissue microarrays (TMA).

  7. 36 CFR 228.102 - Leasing analyses and decisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... at 43 CFR parts 1500-1508, and Forest Service implementing policies and procedures set forth in... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Leasing analyses and decisions. 228.102 Section 228.102 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT...

  8. Consumer Brand Choice: Individual and Group Analyses of Demand Elasticity

    ERIC Educational Resources Information Center

    Oliveira-Castro, Jorge M.; Foxall, Gordon R.; Schrezenmaier, Teresa C.

    2006-01-01

    Following the behavior-analytic tradition of analyzing individual behavior, the present research investigated demand elasticity of individual consumers purchasing supermarket products, and compared individual and group analyses of elasticity. Panel data from 80 UK consumers purchasing 9 product categories (i.e., baked beans, biscuits, breakfast…

  9. Exploration of Heterogeneity in Distributed Research Network Drug Safety Analyses

    ERIC Educational Resources Information Center

    Hansen, Richard A.; Zeng, Peng; Ryan, Patrick; Gao, Juan; Sonawane, Kalyani; Teeter, Benjamin; Westrich, Kimberly; Dubois, Robert W.

    2014-01-01

    Distributed data networks representing large diverse populations are an expanding focus of drug safety research. However, interpreting results is difficult when treatment effect estimates vary across datasets (i.e., heterogeneity). In a previous study, risk estimates were generated for selected drugs and potential adverse outcomes. Analyses were…

  10. Progressing from Initially Ambiguous Functional Analyses: Three Case Examples

    ERIC Educational Resources Information Center

    Tiger, Jeffrey H.; Fisher, Wayne W.; Toussaint, Karen A.; Kodak, Tiffany

    2009-01-01

    Most often functional analyses are initiated using a standard set of test conditions, similar to those described by Iwata, Dorsey, Slifer, Bauman, and Richman [Iwata, B. A., Dorsey, M. F., Slifer, K. J., Bauman, K. E., & Richman, G. S. (1994). "Toward a functional analysis of self-injury." "Journal of Applied Behavior Analysis, 27", 197-209…

  11. Analysing Collisions Using Minkowski Diagrams in Momentum Space

    ERIC Educational Resources Information Center

    Bokor, Nandor

    2011-01-01

    Momentum space and Minkowski diagrams are powerful tools for interpreting and analysing relativistic collisions in one or two spatial dimensions. All relevant quantities that characterize a collision, including the mass, velocity, momentum and energy of the interacting particles, both before and after collision, can be directly seen from a single…

  12. Investigations with Calculators: Abstracts and Critical Analyses of Research.

    ERIC Educational Resources Information Center

    Suydam, Marilyn N., Ed.

    The abstracts and critical analyses of research in this document were prepared and compiled to add to the fund of information on the effects of hand-held calculators on achievement and learning. Since many persons find it difficult to secure original copies of all research studies, the expanded abstracts should provide specific information…

  13. The Importance of Structure Coefficients in Parametric Analyses.

    ERIC Educational Resources Information Center

    Friedrich, Katherine R.

    The recognition that all parametric methods are interrelated, coupled with the notion that structure coefficients are often vital in factor and canonical analyses, suggests that structure coefficients may be important in univariate analysis as well. Using a small, heuristic data set, this paper discusses the importance of structure coefficients…

  14. How Extension Can Help Communities Conduct Impact Analyses.

    ERIC Educational Resources Information Center

    Wisconsin Univ., Madison. Dept. of Agricultural Journalism.

    Intended to provide guidance to Extension specialists and agents faced with requests for impact analyses from communities experiencing economic development, this report also summarizes issues that need to be considered. The first section, on private sector impacts, addresses questions on predicting changes in production, employment, and housing…

  15. 32 CFR 651.27 - Programmatic NEPA analyses.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 4 2014-07-01 2013-07-01 true Programmatic NEPA analyses. 651.27 Section 651.27 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY ENVIRONMENTAL ANALYSIS OF ARMY ACTIONS (AR 200-2) Records and Documents § 651.27 Programmatic NEPA...

  16. 32 CFR 651.27 - Programmatic NEPA analyses.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 4 2012-07-01 2011-07-01 true Programmatic NEPA analyses. 651.27 Section 651.27 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY ENVIRONMENTAL ANALYSIS OF ARMY ACTIONS (AR 200-2) Records and Documents § 651.27 Programmatic NEPA...

  17. 32 CFR 651.27 - Programmatic NEPA analyses.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Programmatic NEPA analyses. 651.27 Section 651.27 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY ENVIRONMENTAL ANALYSIS OF ARMY ACTIONS (AR 200-2) Records and Documents § 651.27 Programmatic NEPA...

  18. 32 CFR 651.27 - Programmatic NEPA analyses.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 4 2011-07-01 2011-07-01 false Programmatic NEPA analyses. 651.27 Section 651.27 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY ENVIRONMENTAL ANALYSIS OF ARMY ACTIONS (AR 200-2) Records and Documents §...

  19. 32 CFR 651.27 - Programmatic NEPA analyses.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 4 2013-07-01 2013-07-01 false Programmatic NEPA analyses. 651.27 Section 651.27 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY ENVIRONMENTAL ANALYSIS OF ARMY ACTIONS (AR 200-2) Records and Documents §...

  20. Analysing the Use of History of Mathematics through MKT

    ERIC Educational Resources Information Center

    Jankvist, Uffe Thomas; Mosvold, Reidar; Fauskanger, Janne; Jakobsen, Arne

    2015-01-01

    In this article, we analyse three "classical" cases of using history of mathematics in teacher training and reinterpret them using the framework of mathematical knowledge for teaching (MKT). We continue with a discussion of the potential benefits of applying MKT as a framework for discussion in research related to the use of history in…

  1. Activity Theory as a Framework for Analysing Knowledge Building

    ERIC Educational Resources Information Center

    Van Aalst, Jan; Hill, Cher M.

    2006-01-01

    Content analyses of computer databases parsed into notes or ideas do not shed adequate light on the role of collaboration and the Computer-Supported Collaborative Learning environment in knowledge building; analysis of what is happening in the classroom and how students interpret that is also needed. This study used ethnographic methods to explore…

  2. Diagnostic Comparison of Meteorological Analyses during the 2002 Antarctic Winter

    NASA Technical Reports Server (NTRS)

    Manney, Gloria L.; Allen, Douglas R.; Kruger, Kirstin; Naujokat, Barbara; Santee, Michelle L.; Sabutis, Joseph L.; Pawson, Steven; Swinbank, Richard; Randall, Cora E.; Simmons, Adrian J.; Long, Craig

    2005-01-01

    Several meteorological datasets, including U.K. Met Office (MetO), European Centre for Medium-Range Weather Forecasts (ECMWF), National Centers for Environmental Prediction (NCEP), and NASA's Goddard Earth Observation System (GEOS-4) analyses, are being used in studies of the 2002 Southern Hemisphere (SH) stratospheric winter and Antarctic major warming. Diagnostics are compared to assess how these studies may be affected by the meteorological data used. While the overall structure and evolution of temperatures, winds, and wave diagnostics in the different analyses provide a consistent picture of the large-scale dynamics of the SH 2002 winter, several significant differences may affect detailed studies. The NCEP-NCAR reanalysis (REAN) and NCEP-Department of Energy (DOE) reanalysis-2 (REAN-2) datasets are not recommended for detailed studies, especially those related to polar processing, because of lower-stratospheric temperature biases that result in underestimates of polar processing potential, and because their winds and wave diagnostics show increasing differences from other analyses between similar to 30 and 10 hPa (their top level). Southern Hemisphere polar stratospheric temperatures in the ECMWF 40-Yr Re-analysis (ERA-40) show unrealistic vertical structure, so this long-term reanalysis is also unsuited for quantitative studies. The NCEP/Climate Prediction Center (CPC) objective analyses give an inferior representation of the upper-stratospheric vortex. Polar vortex transport barriers are similar in all analyses, but there is large variation in the amount, patterns, and timing of mixing, even among the operational assimilated datasets (ECMWF, MetO, and GEOS-4). The higher-resolution GEOS-4 and ECMWF assimilations provide significantly better representation of filamentation and small-scale structure than the other analyses, even when fields gridded at reduced resolution are studied. The choice of which analysis to use is most critical for detailed transport

  3. Nonlinear Thermal Analyses of a Liquid Hydrogen Tank Wall

    NASA Technical Reports Server (NTRS)

    Smeltzer, Stanley S., III; Waters, W. Allen, Jr.

    2003-01-01

    A thermal evaluation of a composite tank wall design for a liquid hydrogen tank was performed in the present study. The primary focus of the current effort was to perform one-dimensional, temperature nonlinear, transient thermal analyses to determine the through-the-thickness temperature profiles. These profiles were used to identify critical points within the flight envelope that could have detrimental effects on the adhesive bondlines used in the construction of the tank wall. Additionally, this paper presents the finite element models, analysis strategies, and thermal analysis results that were determined for several vehicle flight conditions. The basic tank wall configuration used to perform the thermal analyses consisted of carbon-epoxy facesheets and a Korex honeycomb core sandwich that was insulated with an Airex cryogenic foam and an Alumina Enhanced Thermal Barrier (AETB-12). Nonlinear, transient thermal analyses were conducted using the ABAQUS finite element code. Tank wall models at a windward side location on the fuel tank were analyzed for three basic flight conditions: cold-soak (ground-hold), ascent, and re-entry. Additionally, three ambient temperature boundary conditions were applied to the tank wall for the cold-soak condition, which simulated the launch pad cooldown process. Time-dependent heating rates were used in the analyses of the ascent and reentry segments of the flight history along with temperature dependent material properties. The steady-state through-the-thickness temperature profile from the cold-soak condition was used as the initial condition for the ascent analyses. Results from the nonlinear thermal analyses demonstrated very good correlation with results from similar models evaluated by Northrop- Grumman using a different analysis tool. Wall through-the-thickness temperature gradients as a function of flight time were obtained for future incorporation into a full-scale thermostructural analysis to evaluate the adhesive bondlines

  4. Analyses of altimetry errors using Argo and GRACE data

    NASA Astrophysics Data System (ADS)

    Legeais, Jean-François; Prandi, Pierre; Guinehut, Stéphanie

    2016-05-01

    This study presents the evaluation of the performances of satellite altimeter missions by comparing the altimeter sea surface heights with in situ dynamic heights derived from vertical temperature and salinity profiles measured by Argo floats. The two objectives of this approach are the detection of altimeter drift and the estimation of the impact of new altimeter standards that requires an independent reference. This external assessment method contributes to altimeter calibration-validation analyses that cover a wide range of activities. Among them, several examples are given to illustrate the usefulness of this approach, separating the analyses of the long-term evolution of the mean sea level and its variability, at global and regional scales and results obtained via relative and absolute comparisons. The latter requires the use of the ocean mass contribution to the sea level derived from Gravity Recovery and Climate Experiment (GRACE) measurements. Our analyses cover the estimation of the global mean sea level trend, the validation of multi-missions altimeter products as well as the assessment of orbit solutions.Even if this approach contributes to the altimeter quality assessment, the differences between two versions of altimeter standards are getting smaller and smaller and it is thus more difficult to detect their impact. It is therefore essential to characterize the errors of the method, which is illustrated with the results of sensitivity analyses to different parameters. This includes the format of the altimeter data, the method of collocation, the temporal reference period and the processing of the ocean mass solutions from GRACE. We also assess the impact of the temporal and spatial sampling of Argo floats, the choice of the reference depth of the in situ profiles and the importance of the deep steric contribution. These analyses provide an estimation of the robustness of the method and the characterization of associated errors. The results also allow us

  5. Bayesian inference analyses of the polygenic architecture of rheumatoid arthritis.

    PubMed

    Stahl, Eli A; Wegmann, Daniel; Trynka, Gosia; Gutierrez-Achury, Javier; Do, Ron; Voight, Benjamin F; Kraft, Peter; Chen, Robert; Kallberg, Henrik J; Kurreeman, Fina A S; Kathiresan, Sekar; Wijmenga, Cisca; Gregersen, Peter K; Alfredsson, Lars; Siminovitch, Katherine A; Worthington, Jane; de Bakker, Paul I W; Raychaudhuri, Soumya; Plenge, Robert M

    2012-05-01

    The genetic architectures of common, complex diseases are largely uncharacterized. We modeled the genetic architecture underlying genome-wide association study (GWAS) data for rheumatoid arthritis and developed a new method using polygenic risk-score analyses to infer the total liability-scale variance explained by associated GWAS SNPs. Using this method, we estimated that, together, thousands of SNPs from rheumatoid arthritis GWAS explain an additional 20% of disease risk (excluding known associated loci). We further tested this method on datasets for three additional diseases and obtained comparable estimates for celiac disease (43% excluding the major histocompatibility complex), myocardial infarction and coronary artery disease (48%) and type 2 diabetes (49%). Our results are consistent with simulated genetic models in which hundreds of associated loci harbor common causal variants and a smaller number of loci harbor multiple rare causal variants. These analyses suggest that GWAS will continue to be highly productive for the discovery of additional susceptibility loci for common diseases. PMID:22446960

  6. Iterative categorization (IC): a systematic technique for analysing qualitative data.

    PubMed

    Neale, Joanne

    2016-06-01

    The processes of analysing qualitative data, particularly the stage between coding and publication, are often vague and/or poorly explained within addiction science and research more broadly. A simple but rigorous and transparent technique for analysing qualitative textual data, developed within the field of addiction, is described. The technique, iterative categorization (IC), is suitable for use with inductive and deductive codes and can support a range of common analytical approaches, e.g. thematic analysis, Framework, constant comparison, analytical induction, content analysis, conversational analysis, discourse analysis, interpretative phenomenological analysis and narrative analysis. Once the data have been coded, the only software required is a standard word processing package. Worked examples are provided. PMID:26806155

  7. Applications of MIDAS regression in analysing trends in water quality

    NASA Astrophysics Data System (ADS)

    Penev, Spiridon; Leonte, Daniela; Lazarov, Zdravetz; Mann, Rob A.

    2014-04-01

    We discuss novel statistical methods in analysing trends in water quality. Such analysis uses complex data sets of different classes of variables, including water quality, hydrological and meteorological. We analyse the effect of rainfall and flow on trends in water quality utilising a flexible model called Mixed Data Sampling (MIDAS). This model arises because of the mixed frequency in the data collection. Typically, water quality variables are sampled fortnightly, whereas the rain data is sampled daily. The advantage of using MIDAS regression is in the flexible and parsimonious modelling of the influence of the rain and flow on trends in water quality variables. We discuss the model and its implementation on a data set from the Shoalhaven Supply System and Catchments in the state of New South Wales, Australia. Information criteria indicate that MIDAS modelling improves upon simplistic approaches that do not utilise the mixed data sampling nature of the data.

  8. Residual Stresses and Critical Initial Flaw Size Analyses of Welds

    NASA Technical Reports Server (NTRS)

    Brust, Frederick W.; Raju, Ivatury, S.; Dawocke, David S.; Cheston, Derrick

    2009-01-01

    An independent assessment was conducted to determine the critical initial flaw size (CIFS) for the flange-to-skin weld in the Ares I-X Upper Stage Simulator (USS). A series of weld analyses are performed to determine the residual stresses in a critical region of the USS. Weld residual stresses both increase constraint and mean stress thereby having an important effect on the fatigue life. The purpose of the weld analyses was to model the weld process using a variety of sequences to determine the 'best' sequence in terms of weld residual stresses and distortions. The many factors examined in this study include weld design (single-V, double-V groove), weld sequence, boundary conditions, and material properties, among others. The results of this weld analysis are included with service loads to perform a fatigue and critical initial flaw size evaluation.

  9. Metabolomics Analyses of Cancer Cells in Controlled Microenvironments.

    PubMed

    Gravel, Simon-Pierre; Avizonis, Daina; St-Pierre, Julie

    2016-01-01

    The tumor microenvironment is a complex and heterogeneous milieu in which cancer cells undergo metabolic reprogramming to fuel their growth. Cancer cell lines grown in vitro using traditional culture methods represent key experimental models to gain a mechanistic understanding of tumor biology. This protocol describes the use of gas chromatography-mass spectrometry (GC-MS) to assess metabolic changes in cancer cells grown under varied levels of oxygen and nutrients that may better mimic the tumor microenvironment. Intracellular metabolite changes, metabolite uptake and release, as well as stable isotope ((13)C) tracer analyses are done in a single experimental setup to provide an integrated understanding of metabolic adaptation. Overall, this chapter describes some essential tools and methods to perform comprehensive metabolomics analyses. PMID:27581029

  10. Guide to Coupled Electrostatic-Structural Analyses with Arpeggio

    SciTech Connect

    Porter, Vicki L.

    2006-09-01

    Many applications in micromechanical systems (MEMS) involve electrostatically actuated parts. Arpeggio is a code for facilitating loose coupling between computational mechanics modules in a parallel computing environment. This document describes how to use Arpeggio for coupled elecromechanical analyses using examples commonly encountered in MEMS applications, namely the response of structures to loads imposed by electrostatic fields. For this type of analysis, Arpeggio is used to couple Adagio, a three dimensional finite element code for nonlinear, quasi static or implicit dynamic analysis of three-dimensional structures, with BEM, a boundary integral method code for the analysis of electrostatic fields. This guide describes the methodology used for the loose coupling and the commands the user needs in an input file to perform such an analysis. All commands related to coupled analyses are described and examples are provided.

  11. Star 48 solid rocket motor nozzle analyses and instrumented firings

    NASA Technical Reports Server (NTRS)

    Porter, R. L.

    1986-01-01

    The analyses and testing performed by NASA in support of an expanded and improved nozzle design data base for use by the U.S. solid rocket motor industry is presented. A production nozzle with a history of one ground failure and two flight failures was selected for analyses and testing. The stress analysis was performed with the Champion computer code developed by the U.S. Navy. Several improvements were made to the code. Strain predictions were made and compared to test data. Two short duration motor firings were conducted with highly instrumented nozzles. The first nozzle had 58 thermocouples, 66 strain gages, and 8 bondline pressure measurements. The second nozzle had 59 thermocouples, 68 strain measurements, and 8 bondline pressure measurements. Most of this instrumentation was on the nonmetallic parts, and provided significantly more thermal and strain data on the nonmetallic components of a nozzle than has been accumulated in a solid rocket motor test to date.

  12. Mission and sampling analyses for atmospheric satellite experiments

    NASA Technical Reports Server (NTRS)

    Harrison, Edwin F.

    1990-01-01

    Orbital analyses, instrument-viewing geometry studies, and sampling simulations are performed to define mission concepts for advanced atmospheric research satellite experiments. These analyses are conducted in collaboration with NASA Headquarters and working groups consisting of atmospheric scientists and experiment developers. Analytical techniques are developed and used to optimize geographical coverage, sensor-viewing geometries, data gathering strategies, sampling schemes, orbital characteristics, satellite launch times, and operational modes of the various experiments and mission concepts. Short-term (7 day) Shuttle Missions, the Upper Atmosphere Research Satellite (UARS), and multisatellite missions such as the Earth Observing System (EOS) are being studied. Atmospheric experiments which are being analyzed include nadir-viewing sounders, limb-emission scanners, laser systems, and solar-occultation techniques.

  13. Iterative categorization (IC): a systematic technique for analysing qualitative data

    PubMed Central

    2016-01-01

    Abstract The processes of analysing qualitative data, particularly the stage between coding and publication, are often vague and/or poorly explained within addiction science and research more broadly. A simple but rigorous and transparent technique for analysing qualitative textual data, developed within the field of addiction, is described. The technique, iterative categorization (IC), is suitable for use with inductive and deductive codes and can support a range of common analytical approaches, e.g. thematic analysis, Framework, constant comparison, analytical induction, content analysis, conversational analysis, discourse analysis, interpretative phenomenological analysis and narrative analysis. Once the data have been coded, the only software required is a standard word processing package. Worked examples are provided. PMID:26806155

  14. Computational Analyses of Offset Stream Nozzles for Noise Reduction

    NASA Technical Reports Server (NTRS)

    Dippold, Vance, III; Foster, Lancert; Wiese,Michael

    2007-01-01

    The Wind computational fluid dynamics code was used to perform a series of simulations on two offset stream nozzle concepts for jet noise reduction. The first concept used an S-duct to direct the secondary stream to the lower side of the nozzle. The second concept used vanes to turn the secondary flow downward. The analyses were completed in preparation of tests conducted in the NASA Glenn Research Center Aeroacoustic Propulsion Laboratory. The offset stream nozzles demonstrated good performance and reduced the amount of turbulence on the lower side of the jet plume. The computer analyses proved instrumental in guiding the development of the final test configurations and giving insight into the flow mechanics of offset stream nozzles. The computational predictions were compared with flowfield results from the jet rig testing and showed excellent agreement.

  15. Analyses of a new simplified large deployable reflector structure

    NASA Astrophysics Data System (ADS)

    Zheng, Fei; Chen, Mei; He, Jie

    New large deployable mesh reflectors are frequently used recently. Here we propose a new simplified large deployable reflector structure, with lower surface density and better package ratio both in radial direction and in height direction. Its surface modeling manner is fairly simple. Conceptual design of such a new simplified large deployable reflector structure is described. Deploying ability analyses of the structure with 30m diameter show that the structure can be deployed successfully. Surface precision analyses of the deployed structure show that it has potential to reach surface precision demand. A deploying test of a small deployable model with 3m diameter shows the deploying ability of the backbone. Such a new simplified large deployable reflector structure has potential to be used in future large deployable reflectors in space applications.

  16. An on-belt elemental analyser for the cement industry.

    PubMed

    Lim, C S; Tickner, J R; Sowerby, B D; Abernethy, D A; McEwan, A J; Rainey, S; Stevens, R; Manias, C; Retallack, D

    2001-01-01

    On-line control of raw mill feed composition is a key factor in the improved control of cement plants. A new and improved on-conveyor belt elemental analyser for cement raw mill feed based on neutron inelastic scatter and capture techniques has been developed and tested successfully in Adelaide Brighton's Birkenhead cement plant on highly segregated material with a depth range of 100 to 180 mm. Dynamic tests in the plant have shown analyser RMS total errors of 0.49, 0.52, 0.38 and 0.23 wt% (on a loss free basis) for CaO, SiO2, Al2O3 and Fe2O3 respectively, when 10-minute counting periods are used. PMID:11144240

  17. Multiple-Instrument Analyses of Single Micron-Size Particles

    NASA Astrophysics Data System (ADS)

    Admon, Uri; Donohue, David; Aigner, Helmut; Tamborini, Gabriele; Bildstein, Olivier; Betti, Maria

    2005-08-01

    Physical, chemical, and isotopic analyses of individual radioactive and other particles in the micron-size range, key tools in environmental research and in nuclear forensics, require the ability to precisely relocate particles of interest (POIs) in the secondary ion mass spectrometer (SIMS) or in another instrument, after having been located, identified, and characterized in the scanning electron microscope (SEM). This article describes the implementation, testing, and evaluation of the triangulation POIs re-location method, based on microscopic reference marks imprinted on or attached to the sample holder, serving as an inherent coordinate system. In SEM-to-SEM and SEM-to-SIMS experiments re-location precision better than 10 [mu]m and 20 [mu]m, respectively, is readily attainable for instruments using standard specimen stages. The method is fast, easy to apply, and facilitates repeated analyses of individual particles in different instruments and laboratories.

  18. A high-throughput label-free nanoparticle analyser

    NASA Astrophysics Data System (ADS)

    Fraikin, Jean-Luc; Teesalu, Tambet; McKenney, Christopher M.; Ruoslahti, Erkki; Cleland, Andrew N.

    2011-05-01

    Synthetic nanoparticles and genetically modified viruses are used in a range of applications, but high-throughput analytical tools for the physical characterization of these objects are needed. Here we present a microfluidic analyser that detects individual nanoparticles and characterizes complex, unlabelled nanoparticle suspensions. We demonstrate the detection, concentration analysis and sizing of individual synthetic nanoparticles in a multicomponent mixture with sufficient throughput to analyse 500,000 particles per second. We also report the rapid size and titre analysis of unlabelled bacteriophage T7 in both salt solution and mouse blood plasma, using just ~1 × 10-6 l of analyte. Unexpectedly, in the native blood plasma we discover a large background of naturally occurring nanoparticles with a power-law size distribution. The high-throughput detection capability, scalable fabrication and simple electronics of this instrument make it well suited for diverse applications.

  19. Dynamic behaviour of a rolling tyre: Experimental and numerical analyses

    NASA Astrophysics Data System (ADS)

    Gonzalez Diaz, Cristobal; Kindt, Peter; Middelberg, Jason; Vercammen, Stijn; Thiry, Christophe; Close, Roland; Leyssens, Jan

    2016-03-01

    Based on the results of experimental and numerical analyses, the effect of rotation on the tyre dynamic behaviour is investigated. Better understanding of these effects will further improve the ability to control and optimize the noise and vibrations that result from the interaction between the road surface and the rolling tyre. Therefore, more understanding in the complex tyre dynamic properties will contribute to develop tyre design strategies to lower the tyre/road noise while less affecting other tyre performances. The presented work is performed in the framework of the European industry-academia project TIRE-DYN, with partners Goodyear, Katholieke Universiteit Leuven and LMS International. The effect of rotation on the tyre dynamic behaviour is quantified for different operating conditions of the tyre, such as load, air pressure and rotation speed. By means of experimental and numerical analyses, the effects of rotation on the tyre dynamic behaviour are studied.

  20. The moral economy of austerity: analysing UK welfare reform.

    PubMed

    Morris, Lydia

    2016-03-01

    This paper notes the contemporary emergence of 'morality' in both sociological argument and political rhetoric, and analyses its significance in relation to ongoing UK welfare reforms. It revisits the idea of 'moral economy' and identifies two strands in its contemporary application; that all economies depend on an internal moral schema, and that some external moral evaluation is desirable. UK welfare reform is analysed as an example of the former, with reference to three distinct orientations advanced in the work of Freeden (1996), Laclau (2014), and Lockwood (1996). In this light, the paper then considers challenges to the reform agenda, drawn from third sector and other public sources. It outlines the forms of argument present in these challenges, based respectively on rationality, legality, and morality, which together provide a basis for evaluation of the welfare reforms and for an alternative 'moral economy'.